Foamed polyurethane material

Abstract

To provide a foamed urethane raw material having high toughness and impact resilience, a light weight, and capable of suppressing a change of physical property due to a long term usage, further excellent in demoldability.SOLUTION: A foamed polyurethane raw material comprising a cured product of a composition containing polytetramethylene glycol, a diisocyanate containing a diphenylmethane diisocyanate-based first diisocyanate, a blowing agent, a catalyst, and a foam stabilizer, wherein a mass ratio of the diisocyanate to a total mass of the cured product is 10 mass% to 18 mass%, a mass ratio of the first diisocyanate to the total mass of the cured product is 10 mass% to 18 mass%, the apparent density is 300 kg / m3 to 500 kg / m3, and the independent blowing rate is 0% to 20%, and a rebound resilience is more than 75% and 90% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a foamed polyurethane material.

Background Art

[0002] Foamed polyurethane materials are widely used in various applications such as sports goods like batting bats and protectors, and shoes. Such foamed polyurethane materials are disclosed, for example, in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Technologies related to foamed polyurethane materials have been conventionally studied, including Patent Document 1 and the like. However, the current situation is that the technologies for satisfying various properties of foamed polyurethane materials are insufficient.

[0005] The present disclosure has been made in view of such a situation, and the problem to be solved by the embodiments of the present disclosure is to provide a foamed polyurethane material having high toughness and resilience, being lightweight, suppressing changes in physical properties due to long-term use, and having good mold release properties during manufacturing.

Means for Solving the Problems

[0006] The present disclosure includes the following aspects. <1> It is composed of a cured product of a composition containing polytetramethylene glycol, a diisocyanate containing a first diisocyanate of diphenylmethane diisocyanate, a foaming agent, a catalyst, and a foam stabilizer. The mass ratio of the diisocyanate to the total mass of the cured product is 10% by mass to 18% by mass, The mass ratio of the first diisocyanate to the total mass of the cured product is 10% by mass to 18% by mass, The apparent density is 300 kg / m 3 ~500 kg / m 3 and it is a foamed polyurethane material with a closed cell ratio of 0% to 20% and a rebound resilience ratio of more than 75% and 90% or less. <2> The above composition contains a second diisocyanate having an isocyanate group content of more than 33.6% by mass, wherein the second diisocyanate contains one or more selected from the group consisting of toluene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, norbornene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. The foamed polyurethane material according to <1>. <3> At least a part of the diisocyanate is a prepolymer with polytetramethylene glycol. The foamed polyurethane material according to <1> or <2>. <4> The above composition contains a cell opener containing one or more selected from the group consisting of low molecular diol, polycaprolactone diol, monofunctional polyol of polypropylene glycol type, bifunctional polyol of polypropylene glycol type, polyether acetate ester, polybutene, and paraffin oil. The foamed polyurethane material according to any one of <1> to <3>. <5> The 30% compression set is 20% or less, the 30% compression hardness at 23°C is 0.2 MPa to 0.6 MPa, and it is for a baseball bat. The foamed polyurethane material according to any one of <1> to <4>. <6> The 30% compression hardness at 0°C is 0.2 MPa to 1.0 MPa, and it is for a baseball bat. The foamed polyurethane material according to any one of <1> to <5>. <7> The ratio of the 30% compression hardness at 0°C to the 30% compression hardness at 23°C is 200% or less, and it is for a baseball bat, the foamed polyurethane material according to any one of <1> to <6>.

Advantages of the Invention

[0007] According to an embodiment of the present disclosure, there is provided a foamed polyurethane material having high toughness and resilience, being lightweight, capable of suppressing changes in physical properties due to long-term use, and further having good demolding properties during manufacturing.

Modes for Carrying Out the Invention

[0008] Hereinafter, details of the foamed polyurethane material according to the present disclosure will be described.

[0009] In the present disclosure, a numerical range indicated using "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerically described stepwise range. Further, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, the content of each component means the total amount of a plurality of substances when there are a plurality of substances corresponding to each component, unless otherwise specified.

[0010] The foamed polyurethane material according to the present disclosure is composed of a cured product of a composition (hereinafter also referred to as "urethane raw material liquid") containing polytetramethylene glycol (PTMG), a diisocyanate containing a first diisocyanate of diphenylmethane diisocyanate (MDI) type, a foaming agent, a catalyst, and a foam stabilizer. The mass ratio of the diisocyanate (that is, all the diisocyanates in the urethane raw material liquid) to the total mass of the cured product is 10% by mass to 18% by mass, and the mass ratio of the first diisocyanate to the total mass of the cured product is 10% by mass to 18% by mass. In addition, the foamed polyurethane material according to the present disclosure has an apparent density of 300 kg / m 3 ~500 kg / m 3 and an independent bubble rate of 0% to 20%, and a resilience ratio of more than 75% and 90% or less. All the diisocyanates in the urethane raw material liquid may be referred to as "total diisocyanates".

[0011] In order to improve various properties of the foamed polyurethane material, various techniques have been studied. For example, Patent Document 1 describes a foamed polyurethane material obtained from a predetermined polytetraethylene glycol and 1,5-naphthalene diisocyanate and having a predetermined density and the like. However, in the technique described in Patent Document 1, it may be difficult to satisfy various properties required for the foamed polyurethane material. Specifically, when the main component of the diisocyanate is 1,5-naphthalene diisocyanate, the resulting polyurethane material tends to have a high closed cell rate and low elongation. Further, since the melting point of 1,5-naphthalene diisocyanate is 130°C, it is difficult to produce it as a monomer alone, and generally it is used in the form of a prepolymer. However, this prepolymer is likely to self-gel during storage and needs to be used within the same day or the next day, and there are significant limitations in the production process.

[0012] The foamed polyurethane material according to the present disclosure has a low proportion of diphenylmethane diisocyanate-based first diisocyanate and diisocyanate containing the first diisocyanate (i.e., total diisocyanate) with respect to the total amount of the cured product. That is, the foamed polyurethane material according to the present disclosure has a large soft segment ratio, and is obtained by reacting and foaming a urethane raw material liquid in which a foaming agent, a catalyst, and a foam stabilizer are used in combination. Therefore, the foamed polyurethane material according to the present disclosure is excellent in toughness and resilience, and furthermore, is lightweight and can suppress changes in physical properties due to long-term use. Thus, the foamed polyurethane material according to the present disclosure can satisfy many characteristics.

[0013] The foamed polyurethane material according to the present disclosure can be used for various applications, but is particularly suitable as a foamed polyurethane material for a hitting bat. The foamed polyurethane material according to the present disclosure does not have too high hardness and has high resilience. Therefore, when hitting a ball with a bat using the foamed polyurethane material for a hitting bat according to the present disclosure, the ball is difficult to bend, and the flying distance of the hit ball can be improved.

[0014] (PTMG) Examples of PTMG include polyalkylene glycol obtained by ring-opening polymerization of tetrahydrofuran. As PTMG, in addition to the tetramethylene oxy structure, a polyalkylene glycol having other alkylene structural units (ethylene oxy structural unit, propylene oxy structural unit, etc.) may be used. However, PTMG preferably has a tetramethylene oxy structural unit of 50% by mass or more (preferably 80% by mass or more, more preferably 90% by mass or more). PTMG may be used alone or in combination of two or more.

[0015] The number average molecular weight Mn of PTMG is preferably 2000 to 5000, more preferably 3000 to 4000. When the number average molecular weight Mn of PTMG is within the above range, the elongation of the obtained foamed polyurethane material is high, so it is tough and has excellent resilience.

[0016] Here, the number-average molecular weight Mn is the molecular weight obtained by assuming the number of functional groups to be 2 based on the measured value of the hydroxyl value according to JIS K0070 (1992). The average molecular weight of other components is also measured in the same manner.

[0017] The content of PTMG is preferably 79% by mass to 92% by mass, more preferably 82% by mass to 89% by mass, based on the cured product of the urethane composition. When the content of PTMG is within the above range, the elongation of the obtained foamed polyurethane material is high, so it is tough and has excellent resilience.

[0018] (Diisocyanate) The diisocyanate in the urethane raw material liquid necessarily contains an MDI-based diisocyanate (the first diisocyanate). That is, all the diisocyanates may be the first diisocyanate alone, or a combination of the first diisocyanate and a diisocyanate other than the MDI-based diisocyanate (for example, the second diisocyanate).

[0019] The diisocyanate may be used alone or in combination of two or more. When used alone, an MDI-based first diisocyanate is used as the diisocyanate.

[0020] The mass ratio of the diisocyanate (that is, all the diisocyanates) to the total mass of the cured product (hereinafter sometimes simply referred to as the "monomer mass ratio of all the diisocyanates") is 10% by mass to 18% by mass. By setting the monomer mass ratio of all the diisocyanates to 18% by mass or less, a high resilience rate can be obtained. Since the monomer mass ratio of the first diisocyanate is 10% by mass or more as described later, the monomer mass ratio of all the diisocyanates is also 10% by mass or more. From the viewpoint of increasing the resilience rate, the monomer mass ratio of all the diisocyanates is preferably 10% by mass to 18% by mass, more preferably 10% by mass to 15% by mass.

[0021] At least a part of the diisocyanate is preferably a prepolymer with polytetramethylene glycol. This enables the use of a diisocyanate with a high melting point such as phenylene diisocyanate (PDI) in liquid form and facilitates the improvement of the physical properties of the foamed polyurethane material. The prepolymer with polytetramethylene glycol is one of the prepolymer-modified isocyanates (or isocyanate-containing prepolymers).

[0022] In certain embodiments, a part of the diisocyanate may be a prepolymer with polytetramethylene glycol and may be used in combination with other diisocyanates that do not form prepolymers. In other embodiments, all of the diisocyanate may be a prepolymer with polytetramethylene glycol.

[0023] (The first diisocyanate of the MDI type) The first diisocyanate of the MDI type is a diisocyanate having a diphenylmethane diisocyanate skeleton. Examples of the first diisocyanate of the MDI type include 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-MDI, 2,2'-MDI, crude MDI (Cr-MDI), carbodiimide-modified MDI, prepolymer-modified MDI, and the like. Among these, 4,4'-MDI and prepolymer-modified MDI, which is a modified form of 4,4'-MDI, are preferred because they have high reactivity and the resulting polyurethane material has excellent toughness and resilience. The first diisocyanate of the MDI type may be used alone or in combination of two or more.

[0024] The mass ratio of the first diisocyanate to the total mass of the cured product (hereinafter sometimes simply referred to as "monomer mass ratio of the first diisocyanate") is 10% to 18% by mass. By setting the monomer mass ratio of the first diisocyanate to 10% by mass or more, good mold release properties can be obtained. As described above, since the monomer mass ratio of the total diisocyanate is 18% by mass or less, the monomer mass ratio of the first diisocyanate is also 18% by mass or less. From the viewpoint of ensuring reactivity and increasing the resilience modulus, the monomer mass ratio of the first diisocyanate is preferably 10% to 18% by mass, more preferably 12% to 15% by mass.

[0025] The monomer mass ratio of the first diisocyanate of 10% to 18% by mass corresponds to approximately 12 parts to 22 parts by mass with respect to 100 parts by mass of PTMG. Thereby, the resilience of the polyurethane material can be increased, and it is possible to prevent the hardness from becoming excessively high.

[0026] Here, examples of the prepolymer-modified isocyanate (MDI-based isocyanate-containing prepolymer) include prepolymer-modified isocyanates in which MDI-based isocyanate is modified with a divalent alcohol having 2 to 18 carbon atoms such as ethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and 1,10-decanediol; polypropylene glycol-based glycols; PTMG-based glycols; polycarbonate-based glycols, etc. In this prepolymer-modified isocyanate, the content of MDI-based isocyanate with respect to the prepolymer is preferably 10% to 50% by mass (more preferably 15% to 45% by mass) from the viewpoints of toughness, resilience, and low-temperature properties.

[0027] (The second diisocyanate) Together with the first diisocyanate of the MDI type, a second diisocyanate having an isocyanate group content of more than 33.6% by mass may be used. Thereby, the content of the isocyanate group can be increased with respect to the total of all diisocyanates. Therefore, while overall reducing the amount of diisocyanate required to obtain the desired properties, it is easy to increase the resilience and prevent the hardness from becoming excessively high.

[0028] The content of the isocyanate group (hereinafter also referred to as "NCO%") is the ratio of the mass of the isocyanate group to the molecular weight of the diisocyanate. The NCO% of the first diisocyanate of the MDI type is 33.6% by mass, and it is suitable because a higher diisocyanate weight ratio can be achieved by using it in combination with a second diisocyanate having a higher NCO% than this.

[0029] In the second diisocyanate having an NCO% of more than 33.6% by mass, the upper limit of the NCO% is not particularly limited. For example, phenylenediisocyanate (PDI) is 52.5% by mass. From the viewpoint of the resilience ratio, a higher NCO% is preferable. The second diisocyanate to be used in combination may be a single type or two or more types may be used.

[0030] The NCO% is a value measured in accordance with JIS K 1603-1:2007 (ISO14896:2000).

[0031] The second diisocyanate preferably contains one or more selected from the group consisting of toluene diisocyanate (TDI), phenylenediisocyanate (PDI), naphthalene diisocyanate (NDI), xylylene diisocyanate (XDI), hydrogenated XDI, norbornene diisocyanate (NBDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI).

[0032] PDI is preferably used in a small ratio of 0.5% by mass to 2.0% by mass with respect to the total mass of the cured product because the toughness and 30% compression set are improved. In addition, TDI is preferably used in a proportion of 1% by mass to 2.5% by mass based on the total mass of the cured product, as it can reduce the compression hardness, enhance the cell interconnectivity, and lower the closed-cell ratio. In addition, XDI, hydrogenated XDI (H6XDI), NBDI, IPDI, HDI, and NDI are preferably used in a small proportion relative to PTMG, as it can easily prevent the hardness from becoming excessively high.

[0033] Among these, PDI and TDI are more preferable from the viewpoints of reactivity, compression hardness, strength, cell interconnectivity, and storage stability.

[0034] When using PDI and NDI in combination, it is often used as a prepolymer and can be dissolved in the diisocyanate for use.

[0035] The mass ratio of the second diisocyanate to the total mass of the cured product is preferably 0.2% by mass to 5% by mass, and more preferably 0.5% by mass to 3% by mass.

[0036] The monomer mass ratio of the total diisocyanate is calculated by the following procedure. First, calculate the total input amount of all the components (polyol, cell opener, foam stabilizer, catalyst, blowing agent, isocyanate, etc.) introduced. Here, when water is used as the blowing agent, the gas loss is converted by the following formula and subtracted from the total input amount. Gas loss = amount of water × 44.01 (CO 2 molecular weight) × 18.016 (H 2 O molecular weight) In this way, the value obtained by subtracting the gas loss from the total input amount is taken as the total mass of the cured product. Next, determine the input amount of the diisocyanate (monomer). In addition, when using two or more types of diisocyanates, sum them all up. The ratio of this diisocyanate (monomer) amount to the total mass of the cured product, expressed as a percentage, is the monomer mass ratio of the total diisocyanate. Here, when a prepolymer is used as the diisocyanate, the amount of diisocyanate (monomer) in the prepolymer is calculated from the ratio of prepolymer synthesis (polyol / diisocyanate). The monomer weight ratio of the first diisocyanate is calculated by the following procedure. Calculate the MDI monomer used in the MDI monomer and / or MDI prepolymer, and obtain the input amount of the first diisocyanate. Divide this amount of the first diisocyanate (monomer) by the total mass of the cured product and express it as 100%, which is the monomer mass ratio of the first diisocyanate.

[0037] (Blowing agent) Examples of the blowing agent include water, low-boiling organic solvents (such as cyclopentane and dichloromethane), halogenated hydrocarbons, and mixtures thereof. Further, it is also preferable to use the so-called mechanical froth method in which an inert gas such as air or nitrogen is stirred with an oximixer or the like into the raw materials used to entrain bubbles. The blowing agent may be used alone or in combination of two or more.

[0038] When the blowing agent is water, its content is preferably 0.1 part by mass to 3.0 parts by mass, more preferably 0.5 part by mass to 1.2 parts by mass with respect to 100 parts by mass of PTMG. When water is used as the blowing agent, the lower the content, the lower the pseudo-crosslinking density of the foam and the higher the resilience modulus, which is preferable for the rebound of the hit ball. On the other hand, if the water content is low, there is a possibility of insufficient filling during mold molding, so the water content needs to be determined in consideration of the shape and performance.

[0039] (Catalyst) Examples of the catalyst include organometallic compound-based catalysts, amine-based catalysts, and imidazole-based catalysts.

[0040] Examples of the organometallic compound-based catalysts include organometallic catalysts such as tin-based, titanium-based, bismuth-based, and nickel-based catalysts. For example, there are stannous octylate and dibutyltin dilaurate of organotin compounds. Examples of amine catalysts include amine catalysts such as monoamines, diamines, triamines, cyclic amines, alcohol amines, and ether amines. For example, there are triethylenediamine, triethylamine, n-methylmorpholine, n-ethylmorpholine, N,N,N’,N’-tetramethylbutanediamine, and the like. Examples of imidazole catalysts include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, and the like. The catalyst may be used alone or in combination of two or more.

[0041] The content of the catalyst is preferably 0.1 part by mass to 3 parts by mass, more preferably 0.3 part by mass to 1 part by mass, based on 100 parts by mass of PTMG.

[0042] (Foam stabilizer) Examples of foam stabilizers include silicone compounds, fluorine compounds, and the like. The foam stabilizer may be used alone or in combination of two or more.

[0043] As the foam stabilizer, polyether-modified silicone is preferred. Examples of polyether-modified silicone include graft type with grafted polyether and block type of (polyether / silicone / polyether). Thereby, the closed cell ratio can be easily reduced. Further, when demolding during foam molding in a mold, the foamed polyurethane material can be taken out smoothly.

[0044] The content of the foam stabilizer is preferably 0.3 part by mass to 3 parts by mass, more preferably 0.5 part by mass to 2 parts by mass, based on 100 parts by mass of PTMG.

[0045] (Cell opener) The urethane raw material liquid may contain a cell opener. The cell opener is a component that functions as a foam breaker or defoaming agent. Since the cell opener has an appropriate compatibility with PTMG, it becomes easy to reduce the closed cell ratio without disturbing the cells (bubbles). Therefore, it is easy to enhance the toughness and resilience, and to reduce the 30% compression set. Furthermore, when demolding during foam molding in a mold, the foamed polyurethane material can be taken out more smoothly.

[0046] Examples of the cell opener include well-known foam breakers or defoaming agents such as low molecular weight diols, polycaprolactone diols, monofunctional polyols of the polypropylene glycol (PPG) type, bifunctional polyols of the PPG type, polyether acetate esterified products, polybutene, liquid polybutadiene, polyethylene wax, paraffin oil, long-chain aliphatic alcohols, etc. The molecular weight of the low molecular weight diol is preferably from 66 to 3000, more preferably from 100 to 1500. The cell opener may be used alone or in combination of two or more.

[0047] Among these, the cell opener preferably contains one or more selected from the group consisting of low molecular weight diols, polycaprolactone diols, monofunctional polyols of the PPG type, bifunctional polyols of the PPG type, polyether acetate esterified products, polybutene, and paraffin oil.

[0048] Examples of the bifunctional polyol of the PPG type include polyether polyols obtained by addition polymerization of propylene oxide (hereinafter also referred to as "PO") to a dihydric alcohol, or addition polymerization of propylene oxide and another alkylene oxide other than propylene oxide (such as ethylene oxide (hereinafter also referred to as "EO")). The addition polymerization of propylene oxide and another alkylene oxide may be random addition polymerization or block addition polymerization. Here, examples of the dihydric alcohol include dihydric alcohols having 2 to 10 carbon atoms such as ethylene glycol, propylene glycol, 1,3 - butanediol, 1,4 - butanediol, 1,6 - hexanediol, neopentyl glycol, 1,10 - decanediol, and the like.

[0049] The number average molecular weight Mn of the PPG - based difunctional polyol is preferably from 100 to 10000, more preferably from 400 to 4000. When the number average molecular weight Mn of the PPG - based difunctional polyol is within the above range, the effect of reducing the independent bubble ratio is appropriate, so the cells are not rough, there is no adverse effect on other physical properties, and moreover, the product appearance is good, which is preferable.

[0050] Among these, as the PPG - based difunctional polyol, a difunctional polyol having an ethylene oxide content of 0 mol% to 80 mol% (more preferably 0 mol% to 50 mol%) and a number average molecular weight Mn of 100 to 10000 (more preferably 800 to 3000) is preferable. Here, the ethylene oxide content is the ratio (molar ratio) of ethylene oxide to the total alkylene oxide content added by polymerization.

[0051] The content of the cell opener is preferably from 1 part by mass to 15 parts by mass, more preferably from 2 parts by mass to 10 parts by mass, based on 100 parts by mass of PTMG. When the content of the cell opener is within the above range, there is no adverse effect on the product appearance and the independent bubble ratio can be reduced, which is preferable.

[0052] (Polyfunctional polyol) The urethane raw material liquid may contain a polyfunctional polyol other than PTMG. The polyfunctional polyol may be used alone or in combination of two or more.

[0053] The polyfunctional polyol preferably has 3 or more functional groups from the viewpoint of reducing the 30% compression set, and it becomes easier to reduce the 30% compression set as the number of functional groups increases. From the viewpoint of making it easier to reduce the 30% compression set, the polyfunctional polyol preferably has 3 or 4 functional groups, and a trifunctional polyol is most preferred.

[0054] Examples of the polyfunctional polyol having 3 or more functional groups include trifunctional polyols. Examples of the trifunctional polyol include polyether polyols obtained by addition polymerization of alkylene oxides (ethylene oxide, propylene oxide, etc.) to a trivalent alcohol. The addition polymerization of a plurality of types of alkylene oxides may be random addition polymerization or block addition polymerization. Here, examples of the trivalent alcohol include trivalent alcohols having 3 to 10 carbon atoms such as glycerin and trimethylolpropane.

[0055] As the trifunctional polyol, a trifunctional polyol having an ethylene oxide content of 0 mol% to 20 mol% and a number average molecular weight Mn of 1000 to 6000, obtained by adding propylene oxide and ethylene oxide to trifunctional glycerin or trimethylolpropane, is preferred. Here, the ethylene oxide content is the ratio (molar ratio) of ethylene oxide to the total alkylene oxide content added by addition polymerization.

[0056] Examples of the polyfunctional polyol also include tetrafunctional polyols. Specifically, for example, polyether polyols obtained by addition polymerization of alkylene oxides to ethylenediamine, pentaerythritol, etc. are included.

[0057] In addition, examples of the polyfunctional polyol also include ester polyols obtained by condensation of adipic acid and short-chain diols such as ethylene glycol and 1,4-butanediol with polyfunctional triols such as glycerin.

[0058] The number average molecular weight Mn of the polyfunctional polyol is preferably from 100 to 10,000, more preferably from 400 to 5,000. By setting the number average molecular weight Mn of the polyfunctional polyol within the above range, it becomes easy to ensure toughness and reduce the 30% compression set.

[0059] The content of the polyfunctional polyol is preferably from 1 part by mass to 20 parts by mass, more preferably from 2 parts by mass to 10 parts by mass, based on 100 parts by mass of PTMG100. When the content of the polyfunctional polyol is within the above range, it is preferable because it can suppress a decrease in elongation and effectively reduce the 30% compression set.

[0060] (Other additives) In addition to the above components, the urethane raw material liquid may contain well-known additives such as plasticizers, antioxidants, colorants, ultraviolet absorbers, and inorganic fillers such as calcium carbonate. The additives may be used alone or in combination of two or more.

[0061] Examples of the plasticizer include end-capped polyether polyols, end-capped products of polyester polyols of adipic acid and low molecular diols, esters of monocarboxylic acids and monoalcohols, phthalic acid esters such as dioctyl phthalate, halogenated paraffins such as chlorinated paraffin, and phosphate esters. By using a plasticizer, it is possible to easily prevent the hardness from becoming excessively high.

[0062] The calculation of the parts by mass of each raw material component based on 100 parts by mass of PTMG100 was performed as follows. Each component weight was divided by the PTMG input amount (when using a PTMG-modified prepolymer as the diisocyanate, the amount of PTMG in the prepolymer was calculated from the ratio (polyol / diisocyanate) at the time of prepolymer synthesis and added together), and then multiplied by 100.

[0063] (Properties of the foamed polyurethane material) -Apparent density- The apparent density of the foamed polyurethane material is 300 kg / m3 ~500 kg / m 3 and preferably 350 kg / m 3 ~450 kg / m 3 is. By setting the apparent density of the foamed polyurethane material to 300 kg / m 3 or more, the toughness of the foamed polyurethane material is enhanced. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a batting bat, breakage due to impact during hitting is suppressed. Also, by setting the apparent density of the foamed polyurethane material to 500 kg / m 3 or less, the foamed polyurethane material is lightened. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a batting bat, a lightweight bat can be obtained.

[0064] The apparent density is measured by the following method. First, prepare a sample to be measured (approximate dimensions: 180 mm in length × 140 mm in width × 10 mm in thickness) in an environment of 23 ± 3°C. Next, measure the mass of the sample with a precision balance with an accuracy of 1 / 100 g. Next, using a digital gauge and a measuring head with a diameter of Φ10 mm, measure the thickness dimension of the sample at 9 points with a load of approximately 0.6 N with an accuracy of 1 / 100 mm, and obtain the average value. Measure the longitudinal dimension and the transverse dimension of the sample at 3 points each using a digital caliper, and obtain the average. Calculate the volume of the sample from the obtained dimensions. Then, obtain the apparent density using the formula: apparent density = mass / volume.

[0065] -Closed cell ratio- The closed cell ratio of the foamed polyurethane material is 0% to 20%, preferably 0% to 10%. By setting the closed cell ratio of the foamed polyurethane material to 0% to 20%, it becomes possible to suppress changes in physical properties due to long-term use. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a batting bat, the deterioration of the material characteristics is suppressed even by repeated batting. In addition, since it is less likely to tear, it is suitable for long-term use. Furthermore, during the formation of the foamed polyurethane material, it becomes easy to manufacture with an economical molding cycle. That is, when demolding, it is difficult to shrink after expansion and cooling, the product dimensions are stable, partial deformation is difficult to occur, and the workability is enhanced.

[0066] The closed cell ratio is measured in accordance with the Beckmann method (air comparison type specific gravity measurement method: ASTM D 2856-70). Specifically, a sample with a size of 20 mm × 20 mm × thickness mm is cut out from the measurement target, and the volume (cm 3 ) of the obtained sample is measured with a "930-type air comparison type specific gravity meter" manufactured by BECKMAN-TOSHIBA, LTD. (pressure method). The volume of this measured sample is taken as the measured value. On the other hand, the volume is measured with the sample not placed in the "930-type air comparison type specific gravity meter" to obtain a background measurement value (blank value). Then, the closed cell ratio (closed cell ratio per unit volume of space) Vc (%) is calculated by the following formula. Formula: Vc (%) = [(ΔV - E) / (V - E)] × 100 ΔV: {(measured value) - (blank value)} (cm 3 ) V: Apparent volume of the sample by the water immersion method (cm 3 ) E: Volume of the resin (polyurethane) (cm 3 ) = {(mass of the sample) / (true specific gravity of the sample)}

[0067] -Rebound resilience- The resilience modulus of the foamed polyurethane material is over 75%, preferably 80% or more. By setting the resilience modulus of the foamed polyurethane material to over 75%, excellent resilience can be obtained. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a batting bat, the flight distance of the hit ball is likely to increase. The higher the resilience modulus of the foamed polyurethane material for a batting bat, the more preferable it is. The upper limit of the resilience modulus of the foamed polyurethane material is not particularly limited, but is usually 90%.

[0068] The resilience modulus is measured in accordance with JIS K 6400 (1997 / Method A). A sample to be measured (approximate dimensions: 180 mm in length × 140 mm in width × 10 mm in thickness) is stored in an environment of 23 ± 3°C for one day or more. It is carried out using a "FR-1 type" manufactured by Kobunshi Keiki Co., Ltd. in an environment of 23 ± 3°C. In addition, for samples with a low isocyanate index, since the resin itself has tack, it may not be possible to accurately measure the resilience modulus due to the tack. Therefore, after talc powder (Micro Ace C-3 manufactured by Nippon Talc Co., Ltd.) is sprinkled on the sample surface and gently wiped off with a cloth, a measurement test is carried out.

[0069] -30% Compression set- The 30% compression set of the foamed polyurethane material is preferably 20% or less, more preferably 10% or less. By setting the 30% compression set of the foamed polyurethane material to 20% or less, deterioration due to long-term use can be suppressed. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a batting bat, the flight distance of the hit ball is likely to increase even by repeated hitting.

[0070] The 30% compression set is measured in accordance with JIS K 6400-4 (2004 / Method A). Specifically, a sample with a size of 20 mm × 20 mm is cut out from the measurement object, and the thickness of the obtained sample is measured. Next, the sample is sandwiched between two stainless steel plates through a spacer with a thickness corresponding to 70% of the sample thickness and fixed in a 30% compressed state. In that state, it is held in an oven at 70 °C for 22 hours. Next, it is taken out of the oven and the sample is removed from the stainless steel plate. Then, the thickness of the sample left at room temperature of 23 °C for 30 minutes is measured. And the 30% compression set is calculated based on the following formula. Formula: CS=(t0 - t) / t0×100 t0: Thickness of the sample before compression t: Thickness of the sample after compression

[0071] - 30% Compression hardness - The 30% compression hardness of the foamed polyurethane material at 23 °C is preferably 0.2 MPa to 0.6 MPa, more preferably 0.2 MPa to 0.4 MPa. By setting the 30% compression hardness of the foamed polyurethane material to 0.2 MPa or more, the toughness of the foamed polyurethane material is enhanced. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a baseball bat, breakage due to impact during hitting is less likely to occur. Also, even with the impact during hitting, there is no bottoming and the flying distance of the ball extends. Also, a 30% compression hardness of 0.2 MPa or more makes it easier to ensure the hitting feeling during hitting. On the other hand, by setting the 30% compression hardness to 0.6 MPa or less, deformation of the ball during hitting can be reduced, resulting in an increase in the flying distance and hitting speed.

[0072] When the foamed polyurethane material is used as the foamed polyurethane material for a baseball bat, it is preferable that the 30% compression set is 20% or less and the 30% compression hardness at 23 °C is 0.2 MPa to 0.6 MPa.

[0073] In addition, the 30% compression hardness of the foamed polyurethane material at 0°C is preferably from 0.2 MPa to 1.0 MPa, more preferably from 0.2 MPa to 0.6 MPa. By setting the 30% compression hardness of the foamed polyurethane material to 0.2 MPa or more, it becomes easy to maintain the resilience of the foamed polyurethane material even at low temperatures. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a batting bat, it becomes easy to maintain the flying distance during hitting even in cold seasons such as winter. Also, even with the impact during hitting, there is no bottoming out and the flying distance of the hit ball increases. On the other hand, by setting the 30% compression hardness to 1.0 MPa or less (more preferably 0.6 MPa or less), it is possible to reduce the deformation of the ball during hitting, which as a result leads to an increase in the flying distance and hitting speed.

[0074] The 30% compression hardness at 23°C and 0°C is measured in accordance with JIS K 6400-2 (2012). Specifically, a sample of size 20 mm × 20 mm is cut out from the measurement object, and the thickness of the obtained sample is measured. Next, the sample is compressed at a speed of 10 mm / min using a "Tensilon universal material testing machine UCT-500" manufactured by Ori-on Tech Co., Ltd. Then, the stress at 30% compression with respect to the sample thickness is measured, and the measured value is taken as the 30% compression hardness.

[0075] - 0°C / 23°C Compression Hardness Ratio - The ratio of the 30% compression hardness at 0°C to the 30% compression hardness at 23°C (hereinafter sometimes referred to as the "0°C / 23°C compression hardness ratio") is preferably 200% or less. Thereby, when the foamed polyurethane material is used as the foamed polyurethane material for a batting bat, the batting bat can be used throughout the year with little discomfort in hitting due to temperature differences regardless of the season.

[0076] The above-mentioned respective properties of the foamed polyurethane material can be obtained by adjusting the types and amounts of the components of the urethane raw material liquid for forming the foamed polyurethane material.

[0077] (Manufacturing Method of Foamed Polyurethane Material) The foamed polyurethane material can be manufactured according to a well-known method. For example, after mixing components such as polyol other than the isocyanate component to obtain a polyol component-containing solution, the isocyanate component is added to the polyol component-containing solution to prepare a urethane raw material liquid. After pouring this urethane raw material liquid into a mold having a desired shape, it is heated. Thereby, a foamed polyurethane material is obtained.

[0078] When manufacturing a foamed polyurethane material for a hitting bat, the foamed polyurethane material obtained as described above may be processed into the shape of the hitting part of the hitting bat, and as a mold into which the urethane raw material liquid is poured, a mold having the shape of the hitting part of the hitting bat may be used.

Example

[0079] Hereinafter, the present disclosure will be described more specifically with reference to examples. However, the present disclosure is not limited to these examples.

[0080] <Example 1> The following polyol component preheated to 50°C was precisely weighed into a poly cup and stirred at 3000 rpm for 1 minute using a “High-Speed Emulsification and Dispersion Machine T.K. Homodisper 2.5 Type (DH-2.5 / 1001)” manufactured by Primix Corporation to prepare a polyol component-containing solution.

[0081] - Polyol Component - · Polyol: Polytetramethylene glycol “PTMG3000 (manufactured by Mitsubishi Chemical Corporation, functional group number f = 2, Mn = 2877, OHv = 39.0)” 100 parts by mass · Foam stabilizer: Non-reactive silicone foam stabilizer “DOW CORNING TORAY SZ-1642 (manufactured by Toray Dow Corning Co., Ltd.)” 1 part by mass · Catalyst: Amine-based catalyst “DABCO 33-LV (manufactured by Air Products Japan Co., Ltd.)” 0.1 part by mass, imidazole-based catalyst “Kaolizer No. 120 (manufactured by Kao Corporation)” 0.2 part by mass · Blowing agent: Distilled water 0.9 part by mass

[0082] Next, 21.2 parts of a pre-heated isocyanate solution (equivalent to Index = 100) was added to the obtained polyol component-containing solution, and the mixture was stirred at 5000 rpm for 10 seconds using a "High-Speed Emulsification and Dispersion Machine T.K. Homodisper 2.5 Type (DH-2.5 / 1001)" manufactured by Primix Corporation to prepare a urethane raw material solution.

[0083] - Isocyanate Component - · MDI: Monomeric MDI "Millionate MT (manufactured by Tosoh Corporation, NCO% = 33.58 mass%)"

[0084] Next, a predetermined amount (about 100 g) of the obtained urethane raw material solution was poured into a rectangular depression formed by an aluminum frame mold (inner dimensions: 180 mm in length × 140 mm in width × 10 mm in thickness) and a lower plate (10 mm in thickness) that had been pre-heated to 50°C. After the urethane raw material solution was poured in, the upper lid (made of aluminum, 10 mm in thickness) was quickly placed on top and fixed at four points with a vise. In addition, the inner surfaces of the aluminum mold, lower plate, and upper lid (the contact surfaces with the urethane raw material solution) were pre-coated with a mold release agent "Limricate N848 (manufactured by Chukyo Yushi Co., Ltd.)" so that they could be peeled off after curing, and then heated at 100°C for 30 minutes.

[0085] Next, the aluminum container (the container consisting of the frame mold and the upper lid) fixed with a vise was held in an oven at 50°C for 10 minutes, then taken out of the oven and cooled at room temperature for 10 minutes. When the vise was removed, an expansion tendency was observed, so the vise was tightened again and cooled at room temperature for another 10 minutes. After that, the vise was removed, the upper lid and the lower plate were removed, and the polyurethane foam was taken out of the frame mold (demolding time: 20 minutes). Then, for the purpose of completing the reaction, it was placed in an oven at 50°C for 8 hours. In addition, for examples where expansion is observed in the foam after cooling at room temperature for 10 minutes, and examples where the foam is sticky and cannot be removed from the mold, check whether demolding is possible after holding it in the mold for another 10 minutes. Thereafter, check every 10 minutes, and if demolding is not possible even after 60 minutes, demold it after heating in an oven at 50°C for 8 hours while keeping it in the mold.

[0086] Through the above operations, a foamed polyurethane material was obtained.

[0087] <Examples 2 to 49, Comparative Examples 1 to 12> According to Tables 1 to 13, except for changing the types and amounts (parts) of the components, the target foamed polyurethane material was obtained in the same manner as in Example 1.

[0088] Also, in the tables, the MDI prepolymer, TDI prepolymer, and PDI prepolymer were each synthesized as follows.

[0089] (1) MDI prepolymer The following polyol and diisocyanate were prepared. · Polyol; PTMG3000 (manufactured by Mitsubishi Chemical) 500 g Functionality f = 2, Mn = 3000, OHv = 37.4 · Diisocyanate; Millionate MT (manufactured by Tosoh Corporation) 143.6 g Monomeric MDI, NCO% = 33.58 mass% The polyol and diisocyanate were charged into a 2-liter glass reactor equipped with a stirrer, thermometer, and oil bath, the headspace of the reactor was purged with nitrogen gas, and the reactor was heated. While maintaining the temperature at 75 to 85 °C, the polyol and diisocyanate were reacted. After 2 hours, the heating was stopped. The terminal isocyanate group concentration of the obtained MDI prepolymer was measured, and NCO% = 5.32 mass% was obtained. The measurement of NCO% was carried out in accordance with JIS K 1603-1:2007 (ISO14896:2000).

[0090] (2) TDI prepolymer The following polyol and diisocyanate were prepared. · Polyol; PTMG2000 (manufactured by Mitsubishi Chemical) 500 g Functionality f = 2, Mn = 2000, OHv = 56.1 · Diisocyanate; TDI (T-100) (manufactured by Tokyo Chemical Industry) 96.55 g 2,4-Toluene diisocyanate, NCO% = 48.3 mass% The TDI prepolymer was obtained in the same manner as described above for the MDI prepolymer. Further, the terminal isocyanate group concentration of the obtained TDI prepolymer was measured, and NCO% = 4.3 mass% was obtained.

[0091] (3) PDI prepolymer · Polyol; PTMG3000 (manufactured by Mitsubishi Chemical) 500 g Functionality number f = 2, Mn = 3000, OHv = 37.4 · Diisocyanate; PDI (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 71.25 g Para-phenylene diisocyanate, NCO% = 52.5 mass% The PDI prepolymer was obtained in the same manner as described above for the MDI prepolymer, except that the temperature was set to 80 to 110°C. Further, the terminal isocyanate group concentration of the obtained PDI prepolymer was measured, and NCO% = 4.09 mass% was obtained.

[0092] (Evaluation) The properties of the foamed urethane materials obtained in each example were measured, and various tests were conducted for evaluation.

[0093] The following shows various measurement methods and various tests performed in this example. Note that the various values of the present invention are the values measured by the following measurement methods.

[0094] (Measurement method) - Apparent density - The apparent density was measured by the following method. First, a sample for measurement (approximate dimensions: 180 mm in length × 140 mm in width × 10 mm in thickness) was prepared in an environment of 23 ± 3°C. Next, the weight of the sample was measured with a precision balance with an accuracy of 1 / 100 g. Next, using a digital gauge and a measuring head with a diameter of Φ10 mm, the thickness dimension of the sample was measured at 9 locations with a load of approximately 0.6 N with an accuracy of 1 / 100 mm, and the average value was obtained. The length and width dimensions of the sample were measured at 3 locations each using a digital caliper, and the average was obtained. From the obtained dimensions, the volume of the sample was calculated. Then, the apparent density was obtained using the formula: apparent density = weight / volume.

[0095] -Rebound resilience The rebound resilience was measured in accordance with JIS K 6400 (1997 / Method A). The measurement was carried out by storing a sample of the measurement object (approximate dimensions: 180 mm in length × 140 mm in width × 10 mm in thickness) in an environment of 23 ± 3°C for one day or more. The measurement was performed at 23 ± 3°C using a "FR-1 type" manufactured by Kobunshi Keiki Co., Ltd. In addition, after talc powder (Micro Ace C-3 manufactured by Nippon Talc Co., Ltd.) was sprinkled on the sample surface and gently wiped off with a cloth, the measurement test was carried out.

[0096] -Tensile strength and elongation The tensile strength and elongation were measured in accordance with JIS K 6400-5. The measurement was carried out by punching out the measurement object into a dumbbell No. 2 shape to obtain a sample, and for the obtained sample, using a "Tensilon universal material testing machine UCT-500" manufactured by Ori-on Tech Co., Ltd. at a speed of 200 mm / min. Then, the strength and elongation at the time of sample fracture were measured.

[0097] -Closed cell ratio The closed cell ratio was measured in accordance with the Beckmann method (air comparison type specific gravity measurement method: ASTM D 2856-70). Specifically, a sample with dimensions of 20 mm × 20 mm × thickness mm was cut out from the measurement object, and the volume (cm 3 ) of the obtained sample was measured using a "930 type air comparison type specific gravity meter" manufactured by BECKMAN-TOSHIBA, LTD. (pressure method). This measured volume of the sample was used as the measured value. On the other hand, the volume was measured with the sample not placed in the "930 type air comparison type specific gravity meter" to obtain a background measurement value (blank value). Then, the closed cell ratio (closed cell ratio per unit volume) Vc (%) was calculated by the following formula. Formula: Vc (%) = [(ΔV - E) / (V - E)] × 100 ΔV: {(Measured value) - (Blank value)} (cm 3 ) V: Apparent volume of the sample by water immersion method (cm 3 ) E: Volume of resin (polyurethane) (cm 3 ) = {(Weight of sample) / (True specific gravity of sample)}

[0098] -30% Compressive hardness The 30% compressive hardness at 23°C and 0°C was measured in accordance with JIS K 6400-2 (2012). Specifically, a 20 mm × 20 mm sample was cut out from the measurement object, and the thickness of the obtained sample was measured. Next, the sample was compressed at a speed of 10 mm / min using a "Tensilon universal material testing machine UCT-500" manufactured by Ori-on Tech Co., Ltd. Then, the stress at 30% compression with respect to the sample thickness was measured, and the measured value was taken as the 30% compressive hardness.

[0099] -30% Compressive set The 30% compressive set was measured in accordance with JIS K 6400-4 Method A (2004). Specifically, a 20 mm × 20 mm sample was cut out from the measurement object, and the thickness of the obtained sample was measured. Next, the sample was sandwiched between two stainless steel plates through a spacer with a thickness corresponding to 70% of the sample thickness and fixed in a 30% compressed state. In that state, it was held in an oven at 70°C for 22 hours. Next, it was taken out of the oven and the sample was removed from the stainless steel plates. Then, the thickness of the sample left standing at room temperature of 23°C for 30 minutes was measured. And the 30% compressive set was calculated based on the following formula. Formula: CS=(t0 - t) / t0×100 t0: Thickness of the sample before compression t: Thickness of the sample after compression

[0100] -Situation at demolding After taking out the foamed polyurethane foam from the mold. The situation at demolding of the obtained foamed polyurethane foam was evaluated. During demolding, the expansion (or contraction) of the foamed urethane foam and the condition of skin breakage were checked. In addition, odors (such as the odor of isocyanate) were also checked. In the table, the situation where the foamed urethane foam is overly expanded (or contracted) is denoted as "expansion (or contraction)", the situation where it is slightly expanded (or contracted) is denoted as "swelling (or shrinkage)", and the situation where it is slightly expanded (or contracted) is denoted as "slightly swollen (or slightly shrunk)". Also, the situation where the sample surface is peeled off from the main body or peeled is denoted as "skin loose". Also, when there were no particular problems during demolding, it was denoted as "good".

[0101] -Demolding time- When producing the foamed polyurethane material, as described above, the aluminum container (a container consisting of a frame type and an upper lid) fixed with a vise was held in an oven at 50 °C for 10 minutes, then taken out of the oven and cooled at room temperature for 10 minutes. After cooling at room temperature for 10 minutes, for examples where expansion is observed in the foam and examples where the foam is sticky and cannot be removed from the mold, after holding for an additional 10 minutes while still in the mold, check whether demolding is possible. Thereafter, check every 10 minutes, and those that require 60 minutes or more to demold were determined to have poor demoldability.

[0102] The measurement results of the physical properties and the results of various tests for each example are listed in Tables 1 to 13 below. Also, by comprehensively evaluating the above results, the material samples were classified into three categories of "◎", "○", and "X" according to the following criteria. In Tables 1 to 13, the monomer mass ratio of all diisocyanates is denoted as "total diisocyanate mass ratio", and the monomer mass ratio of the first diisocyanate is denoted as "first diisocyanate (MDI) mass ratio".

[0103] (1) Classification "〇" The monomer mass ratio of all diisocyanates, the monomer mass ratio of the first diisocyanate, the apparent density, the closed cell ratio, and the resilience ratio satisfy the ranges specified in this application, and economical production (demoldability within 50 minutes and good appearance) is possible. Furthermore, it is a sample that satisfies any one or more of the following A to C. A: The 30% compression set is 20% or less, and the 30% compression hardness at 23°C is 0.2 MPa to 0.6 MPa. B: The 30% compression hardness at 0°C is 0.2 MPa to 1.0 MPa. C: The ratio of the 30% compression hardness at 0°C to the 30% compression hardness at 23°C is 200% or less.

[0104] (2) Classification "◎" Among those that satisfy the classification "〇", samples that further satisfy all of A to C.

[0105] (3) Classification "×" Samples that do not satisfy the classification "〇". That is, at least one of the monomer mass ratio of all diisocyanates, the monomer mass ratio of the first diisocyanate, the apparent density, the closed cell ratio, and the rebound resilience does not satisfy the range specified in the present application, or samples for which economical production (demolding within 50 minutes or less and good appearance) is impossible.

[0106]

Table 1

[0107]

Table 2

[0108]

Table 3

[0109]

Table 4

[0110]

Table 5

[0111]

Table 6

[0112]

Table 7

[0113]

Table 8

[0114]

Table 9

[0115]

Table 10

[0116]

Table 11

[0117]

Table 12

[0118]

Table 13

[0119] From the above results, it can be seen that the foamed polyurethane material of the examples is lightweight, has a high resilience modulus, and a low closed cell rate, and is thus suitable as a foamed polyurethane material for, for example, a batting bat. Among these examples, those in which at least one of the 30% compression hardness at 23°C, the 30% compression hardness at 0°C, the 30% compression set, and the 0°C / 23°C compression hardness ratio satisfies the conditions defined in the present disclosure can be more preferably used as a foamed polyurethane material for a batting bat. In addition, it can be seen that the foamed polyurethane material of the example does not exhibit phenomena such as expansion (or shrinkage) and skin breakage during demolding, has good demoldability, high processability, and is easy to manufacture.

[0120] Regarding the details of the abbreviations and the like in the table, they are as follows.

[0121] - Polyol - · PTMG4000: Polytetramethylene glycol "PTMG4000 (manufactured by Mitsubishi Chemical Corporation, functional group number f = 2, Mn = 3728, OHv = 30.1)" · PTMG3000: Polytetramethylene glycol "PTMG3000 (manufactured by Mitsubishi Chemical Corporation, functional group number f = 2, Mn = 2877, OHv = 39.0)" · PTMG2000: Polytetramethylene ether glycol "PTMG2000 (manufactured by Mitsubishi Chemical Corporation, functional group number f = 2, Mn = 1951, OHv = 57.5)" · PTMG1500: Polytetramethylene ether glycol "PTMG1500 (manufactured by Mitsubishi Chemical Corporation, functional group number f = 2, Mn = 1500, OHv = 74.8)"

[0122] - Cell opener - · PL910: Polyether glycol "Sunnex PL910 (manufactured by Sanyo Chemical Industries, Ltd., PO / EO (molar ratio) = 84 / 16, functional group number f = 2, Mn = 898, OHv = 125)"

[0123] - Foam stabilizer - · Foam stabilizer: Non-reactive silicone foam stabilizer "DOW CORNING TORAY SZ-1642 (manufactured by Toray Dow Corning Co., Ltd.)"

[0124] - Catalyst - · 33-LV: Amine catalyst "DABCO 33-LV (manufactured by Air Products Japan Co., Ltd.)" · Kaolizer No.120: Imidazole-based catalyst "Kaolizer No.120 (manufactured by Kao Corporation)"

[0125] - Diisocyanate - · Millionate MT: Monomeric MDI "Millionate MT (manufactured by Tosoh Corporation)", NCO% = 33.58 mass% · TDI (T-65): Toluene diisocyanate "Coronate T-65 (manufactured by Tosoh Corporation)", NCO% = 48.3 mass% · TDI (T-100): 2,6-Toluene diisocyanate "(manufactured by Tokyo Chemical Industry Co., Ltd.)", NCO% = 48.3 mass% · HDI: Hexamethylene diisocyanate "(manufactured by Tokyo Chemical Industry Co., Ltd.)", NCO% = 50.0 mass% · IPDI: Isophorone diisocyanate "(manufactured by Tokyo Chemical Industry Co., Ltd.)", NCO% = 37.8 mass% · XDI: Xylylene diisocyanate "(manufactured by Tokyo Chemical Industry Co., Ltd.)", NCO% = 44.5 mass% · H6XDI: Hydrogenated XDI "Takenate 600 (manufactured by Mitsui Chemicals, Inc.)", NCO% = 43.3 mass% · H12MDI: Dicyclohexylmethane diisocyanate "(manufactured by Tokyo Chemical Industry Co., Ltd.)", NCO% = 31.8 mass% · MDI prepolymer PTMG3000 (Mitsubishi Chemical) / MDI (Millionate MT (manufactured by Tosoh Corporation)) = 100 / 28.72 NCO% = 5.32 · TDI prepolymer PTMG2000 (Mitsubishi Chemical) / TDI (T-100, manufactured by Tokyo Chemical Industry Co., Ltd.) = 100 / 19.31 NCO% = 4.3 · PDI prepolymer PTMG3000 (Mitsubishi Chemical) / PDI (manufactured by Fujifilm Wako Pure Chemical Corporation) = 100 / 14.25 NCO% = 4.09

Claims

1. It consists of a cured product of a composition containing polytetramethylene glycol, a diisocyanate containing a diphenylmethane diisocyanate-based first diisocyanate, a foaming agent, a catalyst, and a foam stabilizer, wherein the mass ratio of the diisocyanate to the total mass of the cured product is 10% by mass to 18% by mass, the mass ratio of the first diisocyanate to the total mass of the cured product is 10% by mass to 18% by mass, Apparent density: 300 kg / m ３ ~500kg / m ３ The closed cell rate is 0% to 20% and the rebound resilience is more than 75% but not more than 90%; the 30% compression set is 20% or less, the 30% compression hardness at 23 °C is 0.2 MPa to 0.6 MPa, and it is for a baseball bat, a foamed polyurethane material.

2. wherein the composition contains a second diisocyanate having an isocyanate group content of more than 33.6% by mass, the second diisocyanate contains one or more selected from the group consisting of toluene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, norbornene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, the foamed polyurethane material according to claim 1.

3. wherein at least a part of the diisocyanate is a prepolymer with polytetramethylene glycol, the foamed polyurethane material according to claim 1 or claim 2.

4. wherein the composition contains a cell opener containing one or more selected from the group consisting of low molecular diol, polycaprolactone-based diol, monofunctional polyol of polypropylene glycol-based, bifunctional polyol of polypropylene glycol-based, polyether acetate esterified product, polybutene, and paraffin oil, the foamed polyurethane material according to any one of claims 1 to 3.

5. the 30% compression hardness at 0 °C is 0.2 MPa to 1.0 MPa, and it is for a baseball bat, the foamed polyurethane material according to any one of claims 1 to 4.

6. the ratio of the 30% compression hardness at 0 °C to the 30% compression hardness at 23 °C is 200% or less, and it is for a baseball bat, the foamed polyurethane material according to any one of claims 1 to 5.

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