JP2023051463A - Foamed urethane raw material - Google Patents

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

The present disclosure relates to foamed polyurethane materials.

Polyurethane foam materials are widely used in various applications such as batting bats, sporting goods such as protectors, and shoes. Such a foamed polyurethane material is disclosed in Patent Document 1, for example.

JP-A-2020-12036

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

The present disclosure has been made in view of such circumstances, and the problem to be solved by the embodiments of the present disclosure is to achieve high toughness and rebound resilience, light weight, and physical properties due to long-term use. To provide a foamed polyurethane material capable of suppressing change and having good releasability during production.

The present disclosure includes the following aspects.
<1> 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,
The mass ratio of 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,
A foamed polyurethane material having an apparent density of 300 kg/m ³ to 500 kg/m ³ , a closed cell ratio of 0% to 20%, and a rebound resilience of more than 75% to 90% or less.
<2> 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 <1> The foamed polyurethane material described in .
<3> The polyurethane foam material according to <1> or <2>, wherein at least part of the diisocyanate is a prepolymer with polytetramethylene glycol.
<4> The composition comprises a group consisting of a low-molecular-weight diol, a polycaprolactone-based diol, a polypropylene glycol-based monofunctional polyol, a polypropylene glycol-based bifunctional polyol, a polyether acetic acid ester, a polybutene, and a paraffinic oil. The polyurethane foam material according to any one of <1> to <3>, including a cell opener including one or more selected.
<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 the composition of <1> to <4> is for a bat. The foamed polyurethane material according to any one of the above.
<6> The polyurethane foam material according to any one of <1> to <5>, which has a 30% compression hardness at 0° C. of 0.2 MPa to 1.0 MPa and is for a ball bat.
<7> Any one of <1> to <6>, wherein the ratio of 30% compression hardness at 0°C to 30% compression hardness at 23°C is 200% or less, and the composition is for a bat. The foamed polyurethane material described in .

According to the embodiments of the present disclosure, a foamed polyurethane material that has high toughness and impact resilience, is lightweight, can suppress changes in physical properties due to long-term use, and is easy to demold during manufacturing. is provided.

Details of the foamed polyurethane material according to the present disclosure will be described below.

In the present disclosure, a numerical range indicated using "to" means a range including the numerical values before and after "to" as the minimum and maximum values, respectively.
In the numerical ranges described step by step in the present disclosure, upper or lower limits described in a certain numerical range may be replaced with upper or lower limits of other numerical ranges described step by step. In addition, in the numerical ranges described in the present disclosure, upper or lower limits described in a certain numerical range may be replaced with values shown in Examples.
In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect.
In the present disclosure, the content of each component means the total amount of the multiple types of substances unless otherwise specified when there are multiple types of substances corresponding to each component.

The foamed polyurethane material according to the present disclosure is a composition ( hereinafter also referred to as "urethane raw material liquid"). 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% to 18% by mass, and the mass ratio of the first diisocyanate to the total mass of the cured product is 10% by mass. ~18% by mass.
Further, the foamed polyurethane material according to the present disclosure has an apparent density of 300 kg/m ³ to 500 kg/m ³ , a closed cell rate of 0% to 20%, and a rebound resilience of more than 75% to 90%. .
All the diisocyanates in the urethane raw material liquid may be called "total diisocyanates".

Various techniques have been studied in order to improve various properties of foamed polyurethane materials. For example, Patent Document 1 describes a foamed polyurethane material obtained from predetermined polytetraethylene glycol and 1,5-naphthalenediisocyanate and having a predetermined density and the like. However, with the technique described in Patent Document 1, it is sometimes difficult to satisfy the various properties required for foamed polyurethane materials. Specifically, when the main diisocyanate is 1,5-naphthalenediisocyanate, the resulting polyurethane material tends to have a high cell content and low elongation. In addition, since the melting point of 1,5-naphthalene diisocyanate is 130° C., it is difficult to produce 1,5-naphthalenediisocyanate as a monomer alone, and it is generally used in the form of a prepolymer. However, this prepolymer tends to self-gel during storage and must be used within the same day or the next day, which imposes considerable restrictions on the production process.

The foamed polyurethane material according to the present disclosure has a low proportion of the diphenylmethane diisocyanate-based first diisocyanate and the diisocyanate containing the first diisocyanate (that is, the total diisocyanate) relative 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 containing a foaming agent, a catalyst, and a foam stabilizer. Therefore, the foamed polyurethane material according to the present disclosure is excellent in toughness and impact resilience, 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 properties.

The foamed polyurethane material according to the present disclosure can be used for various purposes, and is particularly suitable as a foamed polyurethane material for a batting bat.
The foamed polyurethane material according to the present disclosure has not too high hardness and high impact resilience. Therefore, when a ball is hit with a bat using the foamed polyurethane material for a ball-hitting bat according to the present disclosure, the ball is less likely to flex, and the flight distance of the hit ball can be improved.

(PTMG)
Examples of PTMG include polyalkylene glycol obtained by ring-opening polymerization of tetrahydrofuran. PTMG may be polyalkylene glycol having other alkylene structural units (ethyleneoxy structural units, propyleneoxy structural units, etc.) in addition to the tetramethyleneoxy structure. However, PTMG preferably contains 50% by mass or more (preferably 80% by mass or more, more preferably 90% by mass or more) of tetramethyleneoxy structural units.
PTMG may be used individually by 1 type, and may be used together 2 or more types.

The number average molecular weight Mn of PTMG is preferably 2000-5000, more preferably 3000-4000.
When the number average molecular weight Mn of PTMG is within the above range, the elongation of the obtained polyurethane foam material is high, so that it is tough and has excellent impact resilience.

Here, the number-average molecular weight Mn is the molecular weight when the number of functional groups is determined as 2 from the hydroxyl value measured according to JIS K0070 (1992). The average molecular weights of other components are also measured in the same manner.

The content of PTMG is preferably 79% by mass to 92% by mass, more preferably 82% by mass to 89% by mass, relative to the cured product of the urethane composition.
When the content of PTMG is within the above range, the elongation of the obtained polyurethane foam material is high, so that it is tough and excellent in impact resilience.

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

Diisocyanate may be used individually by 1 type, and may be used together 2 or more types. When using one type alone, the first diisocyanate of MDI type is used as the diisocyanate.

The mass ratio of diisocyanate (that is, total diisocyanate) to the total mass of the cured product (hereinafter sometimes simply referred to as "monomer mass ratio of total diisocyanate") is 10% by mass to 18% by mass. A high impact resilience can be obtained by setting the monomer mass ratio of all diisocyanates to 18% by mass or less. As will be described later, since the monomer mass ratio of the first diisocyanate is 10% by mass or more, the monomer mass ratio of all diisocyanates is also 10% by mass or more.
The monomer mass ratio of all diisocyanates is preferably 10% by mass to 18% by mass, more preferably 10% by mass to 15% by mass, from the viewpoint of increasing the modulus of impact resilience.

At least part of the diisocyanate is preferably a prepolymer with polytetramethylene glycol. This makes it possible to use a diisocyanate with a high melting point such as phenylene diisocyanate (PDI) in liquid form, and facilitates improving the physical properties of the foamed polyurethane material.
A prepolymer with polytetramethylene glycol is one of the prepolymer-modified isocyanates (or isocyanate-containing prepolymers).

In some embodiments, some of the diisocyanates may be prepolymers with polytetramethylene glycol and may be used in combination with other diisocyanates that do not form prepolymers.
In other embodiments, all of the diisocyanates may be prepolymers with polytetramethylene glycol.

(MDI-based first diisocyanate)
The first MDI-based diisocyanate is a diisocyanate having a diphenylmethane diisocyanate skeleton.
Examples of the MDI-based first diisocyanate include 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-MDI, 2,2'-MDI, crude MDI (Cr-MDI), carbodiimide-modified Examples include 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 excellent toughness and impact resilience of the resulting polyurethane material.
The first MDI-based diisocyanate may be used singly or in combination of two or more.

The mass ratio of the first diisocyanate to the total mass of the cured product (hereinafter sometimes simply referred to as the "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 releasability can be obtained. As described above, since the monomer mass ratio of all diisocyanates is 18% by mass or less, the monomer mass ratio of the first diisocyanate is also 18% by mass or less.
The monomer mass ratio of the first diisocyanate is preferably 10% by mass to 18% by mass, more preferably 12% by mass to 15% by mass, from the viewpoint of ensuring reactivity and increasing the rebound resilience.

A monomer mass ratio of 10% by mass to 18% by mass in the first diisocyanate corresponds to approximately 12% by mass to 22% by mass with respect to 100% by mass of PTMG. As a result, it is possible to increase the impact resilience of the polyurethane material and prevent the hardness from becoming excessively high.

Here, the prepolymer-modified isocyanate (MDI-based isocyanate-containing prepolymer) includes ethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and 1,10 -divalent alcohols having 2 to 18 carbon atoms such as decanediol; polypropylene glycol-based glycols; PTMG-based glycols; and prepolymer-modified isocyanates obtained by modifying MDI-based isocyanates with polycarbonate-based glycols. In this prepolymer-modified isocyanate, the content of MDI-based isocyanate in the prepolymer is 10% by mass to 50% by mass (preferably 15% by mass to 45% by mass) from the viewpoint of toughness, impact resilience and low temperature properties. is good.

(second diisocyanate)
Along with the MDI-based first diisocyanate, a second diisocyanate having an isocyanate group content greater than 33.6% by weight may be used. Thereby, the content of isocyanate groups can be increased with respect to the total of all diisocyanates. Therefore, it becomes easy to increase the impact resilience and prevent the hardness from becoming excessively high while reducing the overall amount of diisocyanate required to obtain the desired properties.

The isocyanate group content (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 system is 33.6 mass%, which is higher than this. The combined use with the second diisocyanate having a high NCO % is preferable because a high diisocyanate weight ratio can be obtained.

In the second diisocyanate having an NCO% of more than 33.6% by mass, the upper limit of the NCO% is not particularly limited, but for example, phenylene diisocyanate (PDI) is 52.5% by mass. From the viewpoint of rebound resilience, the higher the NCO%, the better.
The second diisocyanate used in combination may be used alone or in combination of two or more.

NCO% is a value measured according to JIS K 1603-1:2007 (ISO14896:2000).

The second diisocyanate includes toluene diisocyanate (TDI), phenylene diisocyanate (PDI), naphthalene diisocyanate (NDI), xylylene diisocyanate (XDI), hydrogenated XDI, norbornene diisocyanate (NBDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate ( HDI).

PDI is preferred because it improves toughness and 30% compression set when used in a small proportion of 0.5% to 2.0% by weight with respect to the total weight of the cured product.
In addition, TDI is used in a proportion of 1% by mass to 2.5% by mass with respect to the total mass of the cured product, thereby lowering the compression hardness and increasing the open-cell property to lower the closed-cell ratio. preferred because it can
Further, XDI, hydrogenated XDI (H6XDI), NBDI, IPDI, HDI, and NDI are preferable because they can easily prevent the hardness from becoming excessively high when used in a small amount with respect to PTMG.

Among these, PDI and TDI are more preferable from the viewpoint of reactivity, compression hardness, strength, open-cell property and storage stability.

When PDI and NDI are used in combination, they may be used as a prepolymer or dissolved in diisocyanate.

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, more preferably 0.5% by mass to 3% by mass.

The monomer mass ratio of all diisocyanates is calculated by the following procedure.
First, the total amount of all ingredients (polyol, cell opener, foam stabilizer, catalyst, foaming agent, isocyanate, etc.) is calculated. Here, when water is used as the foaming agent, the gas loss is converted by the following formula and subtracted from the total input amount.
Gas loss = water amount x 44.01 ( _CO2 molecular weight) x 18.016 ( _H2O 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, the input amount of diisocyanate (monomer) is determined.
In addition, when two or more types of diisocyanates are used, all are totaled. This diisocyanate (monomer) amount is divided by the total mass of the cured product, and expressed as 100% 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 prepolymer synthesis ratio (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 to determine the first diisocyanate charge. The amount of the first diisocyanate (monomer) divided by the total mass of the cured product and displayed as 100% is the monomer mass ratio of the first diisocyanate.

(foaming agent)
Examples of foaming agents include water, low-boiling organic solvents (cyclopentane, dichloromethane, etc.), halogenated hydrocarbons, mixtures thereof, and the like. Furthermore, foaming by a so-called mechanical froth method, in which air or an inert gas such as nitrogen is stirred into the raw material to be used with an Oakes mixer or the like to entrain air bubbles, is also preferable. A foaming agent may be used individually by 1 type, and may be used in combination of 2 or more types.

When the foaming agent is water, the content is preferably 0.1 to 3.0 parts by mass, more preferably 0.5 to 1.2 parts by mass with respect to 100 parts by mass of PTMG. more preferred. When water is used as the foaming agent, the smaller the content, the lower the pseudo-crosslinking density of the foam, and the higher the rebound resilience, which is preferable for the rebound of a hit ball. On the other hand, if the water content is low, there is a possibility that the filling will be insufficient during molding, so it is necessary to determine the water content in consideration of the shape and performance.

(catalyst)
Examples of catalysts include organometallic compound-based catalysts, amine-based catalysts, imidazole-based catalysts, and the like.

Examples of organometallic compound catalysts include organometallic catalysts such as tin-based, titanium-based, bismuth-based, and nickel-based catalysts. Examples include organotin compounds such as stannous octoate and stannic dibutyl laurate. be.
Examples of amine-based catalysts include amine-based catalysts such as monoamines, diamines, triamines, cyclic amines, alcoholamines, and etheramines. Examples include triethylenediamine, triethylamine, n-methylmorpholine, n-ethyl Formoline, N,N,N',N'-tetramethylbutanediamine, and the like.
Examples of imidazole-based catalysts include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole and the like.
A catalyst may be used individually by 1 type, and may be used in combination of 2 or more types.

The content of the catalyst is preferably 0.1 to 3 parts by mass, more preferably 0.3 to 1 part by mass with respect to 100 parts by mass of PTMG.

(foam stabilizer)
Examples of foam stabilizers include silicone compounds and fluorine compounds. A foam stabilizer may be used individually by 1 type, and may be used in combination of 2 or more types.

Polyether-modified silicone is preferred as the foam stabilizer. Examples of the polyether-modified silicone include a graft type in which polyether is grafted, and a (polyether/silicone/polyether) block type. Thereby, the closed cell ratio can be easily reduced. Furthermore, the foamed polyurethane material can be taken out smoothly at the time of demolding when performing foam molding with a mold.

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

(cell opener)
The urethane raw material liquid may contain a cell opener. A cell opener is an ingredient that functions as a foam breaker or defoamer. Since the cell opener has moderate compatibility with PTMG, it becomes easy to reduce the closed cell ratio without damaging the cells (bubbles). Therefore, it is easy to increase the toughness and impact resilience, and to reduce the compression set by 30%. Furthermore, the foamed polyurethane material can be taken out more smoothly at the time of demolding during foam molding with a mold. .

Examples of cell openers include low-molecular-weight diols, polycaprolactone-based diols, polypropylene glycol (PPG)-based monofunctional polyols, PPG-based bifunctional polyols, polyether acetic esters, polybutene, liquid polybutadiene, polyethylene wax, and paraffin-based Known foam breakers or defoamers such as oils, long chain fatty alcohols and the like are included. The molecular weight of the low-molecular-weight diol is preferably 66-3000, more preferably 100-1500. A cell opener may be used individually by 1 type, and may be used in combination of 2 or more types.

Among these, the cell opener is selected from the group consisting of low-molecular-weight diols, polycaprolactone-based diols, PPG-based monofunctional polyols, PPG-based bifunctional polyols, polyether acetates, polybutenes, and paraffinic oils. preferably includes one or more of

As a PPG-based bifunctional polyol, addition polymerization of propylene oxide (hereinafter also referred to as "PO") to a dihydric alcohol, or propylene oxide and other alkylene oxides other than propylene oxide (ethylene oxide (hereinafter also referred to as "EO") and the like) are addition-polymerized polyether polyols. The addition polymerization of propylene oxide and other alkylene oxide may be random addition polymerization or block addition polymerization.
Examples of dihydric alcohols include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and 1,10-decanediol. and dihydric alcohols having 2 to 10 carbon atoms.

The number average molecular weight Mn of the PPG-based bifunctional polyol is preferably from 100 to 10,000, more preferably from 400 to 4,000.
When the number average molecular weight Mn of the PPG-based bifunctional polyol is within the above range, the effect of reducing the closed cell ratio is moderate, so the cells do not become rough, there is no adverse effect on other physical properties, and the product appearance is good. ,preferable.

Among these, the PPG-based bifunctional polyol has 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 800 to 3000) are preferred.
Here, the ethylene oxide content is the ratio (molar ratio) of ethylene oxide to the total content of addition-polymerized alkylene oxide.

The content of the cell opener is preferably 1 part by mass to 15 parts by mass, more preferably 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, the appearance of the product is not adversely affected and the closed cell ratio can be reduced, which is preferable.

(Polyfunctional polyol)
The urethane raw material liquid may contain polyfunctional polyols other than PTMG. Polyfunctional polyol may be used individually by 1 type, and may be used in combination of 2 or more types.

From the viewpoint of reducing the compression set by 30%, the polyfunctional polyol is preferably trifunctional or more, and the more the number of functional groups, the easier it is to reduce the compression set by 30%. From the viewpoint of facilitating the reduction of the 30% compression set, the polyfunctional polyol is preferably trifunctional or tetrafunctional, most preferably trifunctional polyol.

Examples of polyfunctional polyols having 3 or more functional groups include trifunctional polyols. Examples of trifunctional polyols include polyether polyols obtained by addition polymerization of alkylene oxides (ethylene oxide, propylene oxide, etc.) to trihydric alcohols. The addition polymerization of multiple types of alkylene oxides may be random addition polymerization or block addition polymerization. Examples of trihydric alcohols include trihydric alcohols having 3 to 10 carbon atoms such as glycerin and trimethylolpropane.

The trifunctional polyol is obtained by adding propylene oxide and ethylene oxide to trifunctional glycerin or trimethylolpropane, and has an ethylene oxide content of 0 mol% to 20 mol% and a number average molecular weight Mn. Trifunctional polyols with a VA of 1000 to 6000 are preferred.
Here, the ethylene oxide content is the ratio (molar ratio) of ethylene oxide to the total content of addition-polymerized alkylene oxide.

Examples of polyfunctional polyols include tetrafunctional polyols, and specific examples thereof include polyether polyols obtained by addition polymerization of alkylene oxide to ethylenediamine, pentaerythritol, or the like.

Other polyfunctional polyols 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.

The number average molecular weight Mn of the polyfunctional polyol is preferably 100-10,000, more preferably 400-5,000.
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.

The content of the polyfunctional polyol is preferably 1 part by mass to 20 parts by mass, more preferably 2 parts by mass to 10 parts by mass, based on 100 parts by mass of PTMG.
When the content of the polyfunctional polyol is within the above range, the decrease in elongation can be suppressed and the 30% compression set can be effectively decreased, which is preferable.

(Other additives)
In addition to the above components, the urethane raw material liquid may contain known additives such as plasticizers, antioxidants, colorants, ultraviolet absorbers, and inorganic fillers such as calcium carbonate. An additive may be used individually by 1 type, and may be used in combination of 2 or more types.

Examples of plasticizers include terminal-blocked polyether polyols, terminal-blocked polyester polyols of adipic acid and low-molecular-weight diols, esters of monocarboxylic acids and monoalcohols, phthalates such as dioctyl phthalate, and chlorinated paraffins. Halogenated paraffins, phosphate esters, and the like can be mentioned. By using a plasticizer, it is possible to easily prevent the hardness from becoming excessively high.

The parts by mass of each raw material component for 100 parts by mass of PTMG were calculated as follows.
Divide the weight of each component by the amount of PTMG input (when using a PTMG-modified prepolymer as the diisocyanate, calculate the amount of PTMG in the prepolymer from the ratio (polyol/diisocyanate) during prepolymer synthesis and add it up). , multiplied by 100.

(Characteristics of foamed polyurethane material)
-Apparent Density-
The apparent density of the foamed polyurethane material is 300 kg/m ³ to 500 kg/m ³ , preferably 350 kg/m ³ to 450 kg/m ³ . 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 ball-hitting bat, breakage due to impact when hitting a ball is suppressed.
Further, by setting the apparent density of the foamed polyurethane material to 500 kg/m ³ or less, the weight of the foamed polyurethane material is reduced. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a ball-hitting bat, a lightweight bat can be obtained.

Apparent density is measured by the following method.
First, a sample to be measured (approximate dimensions: length 180 mm, width 140 mm, thickness 10 mm) is prepared in an environment of 23±3°C. Next, the mass of the sample is measured with an accuracy of 1/100 g using a precision balance. Next, using a digital gauge, the thickness dimension of the sample is measured at 9 points with an accuracy of 1/100 mm using a probe with a diameter of Φ10 mm and a load of about 0.6 N, and the average value is obtained. The vertical dimension and horizontal dimension of the sample are measured at three points using a digital caliper, and the average is obtained. From each dimension obtained, the volume of the sample is calculated. Then, the apparent density is obtained by the formula: apparent density=mass/volume.

-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 is 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 ball-hitting bat, deterioration of the properties of the material is suppressed even with repeated hitting. Moreover, since it becomes hard to be torn, it is suitable for long-term use. Furthermore, when forming the foamed polyurethane material, it becomes easy to manufacture in an economical molding cycle. In other words, it is difficult to expand during demolding and shrink after cooling, so that product dimensions are stable, partial deformation is less likely to occur, and workability is improved.

The closed cell ratio is measured according to the Beckman method (comparative air specific gravity measurement method: ASTM D 2856-70). Specifically, a sample having a size of 20 mm×20 mm×thickness mm is cut out from the object to be measured, and the volume (cm ³ ) of the obtained sample is measured by BECKMAN-TOSHIBA, LTD. Measured with an air comparison type hydrometer 930 (pressurization method). The measured volume of the sample is used as the measured value. On the other hand, the volume is measured without placing the sample in the "930 type air comparison type hydrometer" to obtain a background measurement value (blank value). Then, the closed cell rate (closed cell rate per space volume) Vc (%) is calculated by the following formula.
Formula: Vc (%) = [(ΔVE) / (VE)] × 100
ΔV: {(measured value)−(blank value)} (cm ³ )
V: Apparent volume of sample by submersion method (cm ³ )
E: Volume (cm ³ ) of resin (polyurethane) = {(mass of sample)/(true specific gravity of sample)}

-Rebound resilience-
The impact resilience of the foamed polyurethane material is more than 75%, preferably 80% or more. Excellent rebound resilience can be obtained by setting the rebound resilience of the foamed polyurethane material to more than 75%. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a ball-hitting bat, the flight distance of a hit ball is likely to increase. As a foamed polyurethane material for a ball-hitting bat, the higher the modulus of rebound resilience, the better. Although the upper limit of the rebound resilience of the foamed polyurethane material is not particularly limited, it is usually 90%.

The impact resilience is measured according to JIS K 6400 (1997/A method). A sample to be measured (approximate dimensions: length 180 mm×width 140 mm×thickness 10 mm) is stored in an environment of 23±3° C. for one day or more. It is carried out in an environment of 23±3° C. using “FR-1 type” manufactured by Kobunshi Keiki Co., Ltd. A sample with a low isocyanate index has tackiness in the resin itself, and it may not be possible to measure the rebound resilience rate accurately due to the tackiness. Therefore, after sprinkling talc powder (Micro Ace C-3, manufactured by Nippon Talc Co., Ltd.) on the surface of the sample, lightly wiping it off with a cloth, the measurement test is performed.

-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 ball-hitting bat, the flight distance of the hit ball is likely to increase even with repeated hits.

30% compression set is measured according to JIS K 6400-4 (2004/A method). Specifically, a sample having a size of 20 mm×20 mm is cut out from the object to be measured, and the thickness of the obtained sample is measured. Next, the sample is sandwiched between two stainless steel plates via a spacer having a thickness corresponding to 70% of the thickness of the sample, and fixed in a 30% compressed state. This state is maintained in an oven at 70° C. for 22 hours. Next, take it out of the oven and remove the sample from the stainless steel plate. After that, the thickness of the sample is measured after being left at room temperature of 23° C. for 30 minutes. Then, the 30% compression set is calculated based on the following formula.
Formula: CS=(t0−t)/t0×100
t0: thickness of sample before compression t: thickness of sample after compression

-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 at 23° C. 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 ball-hitting bat, breakage due to impact at the time of hitting a ball is easily suppressed. In addition, even with the impact of hitting, the flight distance of the hit ball is extended without bottoming out. In addition, the 30% compression hardness of 0.2 MPa or more makes it easy to ensure a good hitting feel. On the other hand, by setting the 30% compression hardness to 0.6 MPa or less, the deformation of the ball when hit can be reduced, resulting in an increase in distance and speed.

When the foamed polyurethane material is used as a foamed polyurethane material for a ball bat, it preferably has a 30% compression set of 20% or less and a 30% compression hardness at 23° C. of 0.2 MPa to 0.6 MPa.

The 30% compression hardness at 0° C. of the foamed polyurethane material is preferably 0.2 MPa to 1.0 MPa, more preferably 0.2 MPa to 0.6 MPa. By setting the 30% compression hardness at 0°C of the polyurethane foam material to 0.2 MPa or more, it becomes easy to maintain the impact resilience of the polyurethane foam material even at low temperatures. Therefore, when the foamed polyurethane material is used as the foamed polyurethane material for a hitting ball bat, it becomes easy to maintain the flight distance when hitting a ball even in a cold season such as winter. In addition, even when the ball hits the ball, it does not bottom out and the flight distance of the ball increases. On the other hand, the 30% compression hardness is set to 1.0 MPa or less (more preferably 0.6 MPa or less) to reduce the deformation of the ball when hit, which results in an increase in distance and speed.

The 30% compression hardness at 23°C and 0°C is measured according to JIS K 6400-2 (2012). Specifically, a sample having a size of 20 mm×20 mm is cut out from the object to be measured, and the thickness of the obtained sample is measured. Next, the sample is compressed at a speed of 10 mm/min using “Tensilon Universal Material Testing Machine UCT-500” manufactured by Orion Tech Co., Ltd. Then, the stress at 30% compression is measured with respect to the thickness of the sample, and the measured value is defined as 30% compression hardness.

-0℃/23℃ compression hardness ratio-
The ratio of 30% compression hardness at 0°C to 30% compression hardness at 23°C (hereinafter sometimes referred to as "0°C/23°C compression hardness ratio") is preferably 200% or less. As a result, when the foamed polyurethane material is used as the foamed polyurethane material for a ball-hitting bat, the batting bat can be used in a state in which there is little sense of incongruity in hitting due to temperature differences throughout the year, regardless of the season.

Each of the above properties of the polyurethane foam material can be obtained by adjusting the types and amounts of the components of the urethane raw material liquid for forming the polyurethane foam material.

(Manufacturing method of polyurethane foam material)
A foamed polyurethane material can be manufactured according to a well-known method. For example, after mixing components other than the isocyanate component such as polyol to obtain a polyol component-containing solution, the isocyanate component is added to the polyol component-containing solution to prepare a urethane raw material solution. This urethane raw material liquid is poured into a mold having a desired shape and then heated. Thereby, a foamed polyurethane material is obtained.

When producing a polyurethane foam material for a ball-hitting bat, the polyurethane foam material obtained as described above may be processed into the shape of the ball-hitting portion of the bat. You may use the type|mold of the shape of the hitting part.

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

<Example 1>
Precisely weigh the following polyol components preheated to 50 ° C. in a plastic cup, and put them in "High-speed emulsifying/dispersing machine TK Homodisper 2.5 type (DH-2.5/1001)" manufactured by Primix Co., Ltd. and stirred at 3000 rpm for 1 minute to prepare a polyol component-containing solution.

-Polyol component-
- Polyol: Polytetramethylene glycol "PTMG3000 (manufactured by Mitsubishi Chemical Corporation, functional group 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 Dow Corning Toray Co., Ltd.) 1 part by mass Catalyst: Amine-based catalyst "DABCO 33-LV (manufactured by Air Products Japan Co., Ltd.)" 0.1 parts by mass, imidazole Catalyst "Kao Riser No. 120 (manufactured by Kao Corporation)" 0.2 parts by mass Blowing agent: Distilled water 0.9 parts by mass

Next, 21.2 parts of a preheated isocyanate liquid (equivalent to Index = 100) was added to the obtained polyol component-containing solution, and "High-speed emulsifying/dispersing machine T.K. 5 type (DH-2.5/1001)”, and stirred at 5000 rpm for 10 seconds to prepare a urethane raw material solution.

-Isocyanate component-
・ MDI: Monomeric MDI "Millionate MT (manufactured by Tosoh Corporation, NCO% = 33.58% by mass)"

Next, the obtained urethane raw material liquid was preheated to 50° C. and consisted of an aluminum frame mold (inner dimensions: length 180 mm, width 140 mm, thickness 10 mm) and a lower plate (thickness 10 mm). A predetermined amount (about 100 g) is put into the rectangular depression. After the urethane raw material liquid was added, a top lid (made of aluminum, thickness 10 mm) was quickly placed and fixed at four points with a vise.
In addition, the inner surfaces of the aluminum formwork, lower plate, and upper lid (surfaces in contact with the urethane raw material liquid) were coated with a mold release agent “Rimrikei N848 (manufactured by Chukyo Yushi Co., Ltd.) in advance so that they can be peeled off after curing. )” and heated at 100° C. for 30 minutes.

Next, the aluminum container (container consisting of a frame and an upper lid) fixed with a vise was held in an oven at 50° C. for 10 minutes, then removed from the oven and cooled to room temperature for 10 minutes. When the vise began to be removed, a tendency to expand was observed, so the vise was tightened again and the tube was cooled to room temperature for an additional 10 minutes. After that, the vice was removed, the upper lid and the lower plate were removed, and the polyurethane foam was removed from the frame mold (demolding time: 20 minutes). It was then placed in an oven at 50°C for 8 hours for the purpose of complete reaction.
In addition, in cases where the foam expands after cooling to room temperature for 10 minutes, or in cases where the foam becomes sticky and cannot be removed from the mold, it should be held in the mold for an additional 10 minutes and then checked to see if it can be removed from the mold. . Thereafter, the mold was checked every 10 minutes, and if the mold could not be demolded after 60 minutes, it was heated in an oven at 50°C for 8 hours while still in the mold, and then demolded.

A foamed polyurethane material was obtained by the above operation.

<Examples 2 to 49, Comparative Examples 1 to 12>
The target foamed polyurethane material was obtained in the same manner as in Example 1, except that the types and amounts (number of parts) of the components were changed according to Tables 1 to 13.

In the table, MDI prepolymer, TDI prepolymer and PDI prepolymer were each synthesized as follows.

(1) MDI Prepolymer The following polyols and diisocyanates were prepared.
· Polyol; PTMG3000 (manufactured by Mitsubishi Chemical) 500 g
Functional group number f=2, Mn=3000, OHv=37.4
・ Diisocyanate; Millionate MT (manufactured by Tosoh Corporation) 143.6 g
Monomeric MDI, NCO% = 33.58 mass%
A glass reactor with a capacity of 2 liters equipped with a stirrer, a thermometer, and an oil bath is charged with a polyol and a diisocyanate, and the space of the reactor is replaced with nitrogen gas to heat the reactor to 75 to 85 ° C. While maintaining the temperature, the polyol and the diisocyanate were allowed to react. After 2 hours, the heating was stopped. The terminal isocyanate group concentration of the obtained MDI prepolymer was measured to obtain NCO%=5.32% by mass.
The NCO% was measured according to JIS K 1603-1:2007 (ISO14896:2000).

(2) TDI Prepolymer The following polyols and diisocyanates were prepared.
· Polyol; PTMG2000 (manufactured by Mitsubishi Chemical) 500g
Functional group number f=2, Mn=2000, OHv=56.1
・ Diisocyanate; TDI (T-100) (manufactured by Tokyo Chemical Industry Co., Ltd.) 96.55 g
2,4-toluene diisocyanate, NCO% = 48.3% by weight
A TDI prepolymer was obtained in a manner similar to that described above for the MDI prepolymer. In addition, the terminal isocyanate group concentration of the obtained TDI prepolymer was measured, and NCO% = 4.3% by mass was obtained.

(3) PDI prepolymer polyol; PTMG3000 (manufactured by Mitsubishi Chemical) 500 g
Functional group number f=2, Mn=3000, OHv=37.4
Diisocyanate; PDI (manufactured by Fujifilm Wako Pure Chemical Industries) 71.25 g
Paraphenylene diisocyanate, NCO% = 52.5 wt%
The PDI prepolymer was obtained in the same manner as described above for the MDI prepolymer, except that the temperature was 80-110°C. Also, the terminal isocyanate group concentration of the obtained PDI prepolymer was measured to obtain NCO%=4.09% by mass.

(evaluation)
The properties of the foamed urethane material obtained in each example were measured, and various tests were conducted for evaluation.

Various measurement methods and various tests performed in the present examples are described below. Various values in the present invention are values measured by the following measuring methods.

(Measuring method)
－Apparent Density－
Apparent density was measured by the following method.
First, a sample to be measured (approximate dimensions: length 180 mm, width 140 mm, thickness 10 mm) was prepared in an environment of 23±3°C. Next, the weight of the sample was measured with an accuracy of 1/100 g using a precision balance. Next, using a digital gauge, the thickness dimension of the sample was measured at 9 points with an accuracy of 1/100 mm with a probe having a diameter of Φ10 mm and a load of about 0.6 N, and the average value was obtained. The vertical dimension and horizontal dimension of the sample were measured at three points using a digital caliper, and the average was obtained. From each dimension obtained, the volume of the sample was calculated. Then, the apparent density was determined by the formula: apparent density=weight/volume.

-Rebound resilience-
The impact resilience was measured according to JIS K 6400 (1997/A method). For the measurement, a sample to be measured (approximate dimensions: length 180 mm, width 140 mm, thickness 10 mm) is stored in an environment of 23±3° C. for one day or longer. It was carried out in an environment of 23±3° C. using “FR-1 type” manufactured by Kobunshi Keiki Co., Ltd. After sprinkling talc powder (Micro Ace C-3, manufactured by Nippon Talc Co., Ltd.) on the surface of the sample, it was lightly wiped off with a cloth, and then the measurement test was performed.

－Tensile Strength/Elongation－
Tensile strength and elongation were measured according to JIS K 6400-5. For the measurement, the object to be measured is punched into a dumbbell No. 2 shape, a sample is obtained, and the obtained sample is subjected to a speed of 200 mm / min with "Tensilon Universal Material Testing Machine UCT-500" manufactured by Orion Tech Co., Ltd. gone. Then, the strength and elongation at breakage of the sample were measured.

－Closed cell ratio－
The closed cell ratio was measured according to the Beckman method (air comparison type specific gravity measurement method: ASTM D 2856-70). Specifically, a sample having a size of 20 mm×20 mm×thickness mm is cut out from the object to be measured, and the volume (cm ³ ) of the obtained sample is measured by BECKMAN-TOSHIBA, LTD. It was measured with an "air comparison type specific gravity meter 930 type" manufactured by Fujikura (pressurization method). The measured volume of the sample was used as the measured value. On the other hand, the volume was measured without placing the sample in the "930 type air comparison type hydrometer" to obtain a background measurement value (blank value). Then, the closed cell rate (closed cell rate per space volume) Vc (%) was calculated by the following formula.
Formula: Vc (%) = [(ΔVE) / (VE)] × 100
ΔV: {(measured value)−(blank value)} (cm ³ )
V: Apparent volume of sample by submersion method (cm ³ )
E: Volume (cm ³ ) of resin (polyurethane) = {(weight of sample)/(true specific gravity of sample)}

-30% compression hardness-
30% compression hardness at 23° C. and 0° C. was measured according to JIS K 6400-2 (2012). Specifically, a sample having a size of 20 mm×20 mm was cut out from the object to be measured, and the thickness of the obtained sample was measured. Next, the sample was compressed at a speed of 10 mm/min using “Tensilon Universal Material Testing Machine UCT-500” manufactured by Orion Tech Co., Ltd. Then, the stress at 30% compression was measured with respect to the thickness of the sample, and the measured value was defined as 30% compression hardness.

-30% compression set-
The 30% compression set was measured according to JIS K 6400-4 A method (2004). Specifically, a sample having a size of 20 mm×20 mm was cut out from the object to be measured, and the thickness of the obtained sample was measured. Next, the sample was sandwiched between two stainless steel plates via a spacer having a thickness corresponding to 70% of the thickness of the sample, and fixed in a 30% compressed state. This state was maintained 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 plate. After that, the thickness of the sample which was left at room temperature of 23° C. for 30 minutes was measured. Then, the 30% compression set was calculated based on the following formula.
Formula: CS=(t0−t)/t0×100
t0: thickness of sample before compression t: thickness of sample after compression

-Situation at the time of demolding-
After removing the expanded polyurethane foam from the frame mould. The state of the resulting polyurethane foam at the time of demolding was evaluated.
As for the condition at the time of demolding, the expansion (or contraction) of the urethane foam and the breakage of the skin were confirmed. In addition, the odor (the odor of isocyanate) was also confirmed. In the table, the state in which the urethane foam expands (or shrinks) excessively is described as "expansion (or shrinkage)", and the state in which it expands (or shrinks) to some extent is described as "expansion (or shrinkage)". , and the state of slight expansion (or contraction) was indicated as "slightly swollen (or slightly contracted)". In addition, the state in which the sample surface was peeled off from the main body or the state in which it was peeled off was described as "skin loose". In addition, when there was no particular problem at the time of demolding, it was described as "good".

- Demolding time -
When producing the foamed polyurethane material, as described above, the aluminum container (container consisting of a frame and an upper lid) fixed with a vise was held in an oven at 50°C for 10 minutes, then removed from the oven and left at room temperature for 10 minutes. cooled. For cases where the foam expands after cooling to room temperature for 10 minutes, or for cases where the foam becomes sticky and cannot be removed from the mold, it is confirmed whether the foam can be demolded after holding it in the mold for an additional 10 minutes. After that, it was checked every 10 minutes, and if it took 60 minutes or more to remove from the mold, it was determined that the mold releasing property was poor.

Tables 1 to 13 below list the results of measuring the physical properties of each example and the results of various tests. Moreover, the above results were comprehensively evaluated, and 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 shown as "total diisocyanate mass ratio", and the monomer mass ratio of the first diisocyanate is shown as "first diisocyanate (MDI) mass ratio".

(1) Division "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 rebound resilience modulus satisfy the ranges specified in the present application, and economical production (removability of 50 minutes or less and good appearance) and further 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: 30% compression hardness at 0° C. is 0.2 MPa to 1.0 MPa.
C: The ratio of 30% compression hardness at 0°C to 30% compression hardness at 23°C is 200% or less.

(2) Division "◎"
Among the samples satisfying the category “◯”, these samples further satisfy all of A to C.

(3) Division "x"
It is a sample that does not satisfy the category "O". 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 impact resilience does not satisfy the range specified in the present application, or economical production (50 minutes It is a sample that cannot be demolded and has a good appearance described below.

From the above results, it can be seen that the foamed polyurethane materials of Examples are lightweight, have a high impact resilience, and have a low closed cell ratio, and are therefore suitable as, for example, foamed polyurethane materials for batting bats. Among these examples, at least one of 30% compression hardness at 23°C, 30% compression hardness at 0°C, 30% compression set, and 0°C/23°C compression hardness ratio are provided in this disclosure. The polyurethane foam material that satisfies the following conditions can be more preferably used as a foamed polyurethane material for a ball-hitting bat.
In addition, it can be seen that the foamed polyurethane materials of the examples do not cause expansion (or shrinkage), skin tearing, or the like when demolded, have good demoldability, are highly workable, and are easy to manufacture.

Details of abbreviations in the table are as follows.

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

-cell opener-
PL910: Polyether glycol "Sannics PL910 (manufactured by Sanyo Chemical Industries, Ltd., PO/EO (molar ratio) = 84/16, number of functional groups f = 2, Mn = 898, OHv = 125)

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

-catalyst-
・ 33-LV: Amine catalyst “DABCO 33-LV (manufactured by Air Products Japan Co., Ltd.)”
・ Kao riser No. 120: Imidazole catalyst "Kao riser No. 120 (manufactured by Kao Corporation)"

-Diisocyanate-
・ Millionate MT: Monomeric MDI "Millionate MT (manufactured by Tosoh Corporation)", NCO% = 33.58% by 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% by mass
・IPDI: isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.), NCO% = 37.8% by mass
・XDI: Xylylene diisocyanate "manufactured by Tokyo Chemical Industry Co., Ltd.", NCO% = 44.5% by mass
・H6XDI: Hydrogenated XDI “Takenate 600 (manufactured by Mitsui Chemicals, Inc.)”, NCO% = 43.3% by mass
・ H12MDI: Dicyclohexylmethane diisocyanate "manufactured by Tokyo Chemical Industry Co., Ltd.", NCO% = 31.8% by 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 Industries, Ltd.) = 100/14.25
% NCO = 4.09

Claims (7)

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,
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,
A foamed polyurethane material having an apparent density of 300 kg/m ³ to 500 kg/m ³ , a closed cell ratio of 0% to 20%, and a rebound resilience of more than 75% to 90% or less. The composition contains a second diisocyanate having an isocyanate group content of more than 33.6% by mass,
2. The second diisocyanate comprises one or more selected from the group consisting of toluene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, norbornene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate. The foamed polyurethane material described in . The foamed polyurethane material according to claim 1 or 2, wherein at least part of the diisocyanate is a prepolymer with polytetramethylene glycol. The composition is selected from the group consisting of low-molecular-weight diols, polycaprolactone-based diols, polypropylene glycol-based monofunctional polyols, polypropylene glycol-based bifunctional polyols, polyether acetic esters, polybutenes, and paraffinic oils. A foamed polyurethane material according to any one of claims 1 to 3, comprising one or more cell openers. 30% compression set is 20% or less, 30% compression hardness at 23° C. is 0.2 MPa to 0.6 MPa, and it is for a ball bat. The foamed polyurethane material described in the paragraph. The foamed polyurethane material according to any one of claims 1 to 5, which has a 30% compression hardness at 0°C of 0.2 MPa to 1.0 MPa and is for a ball-hitting bat. 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 ball-hitting bat according to any one of claims 1 to 6. Foamed polyurethane material.