JP2020002202A - Polyurethane foam - Google Patents

Abstract

To provide a polyurethane foam excellent in tensile strength and tensile elongation even with high impact resilience, and a shoe bottom member using the same.SOLUTION: There is provided a polyurethane foam consisting of a polyurethane raw material composition containing a polyol component, an isocyanate component, a foaming agent, a catalyst, and a foam stabilizer, in which the polyol component contains polytetramethylene ether glycol (PTMG(I)) having weight average molecular weight of over 4000 to 7000 or less, average functional group number of 2 to 3, and average hydroxyl group value of 25 mgKOH/g to 80 mgKOH/g, impact resilience of the polyurethane foam measured according to JIS K 6255 is 75% or more, tensile strength of the polyurethane foam measured according to JIS K 6251 is 1.0 MPa or more, and tensile elongation is 150% or more.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a polyurethane foam having high rebound resilience and suitable for a material of a sole member.

  Conventionally, foams such as polyurethane foam and EVA (ethylene-vinyl acetate copolymer) foam have been used as shoe sole members. A shoe sole member made of a foam is excellent in shock absorption, and is used as a shoe sole member of exercise shoes for walking, running, trekking and the like, as well as shoes for general use. In the case of athletic shoes, there are demands for those that have further excellent physical properties such as durability, light weight, and rebound resilience.

  For example, shoes in which a material having excellent rebound resilience is used for a sole member support the kicking out and facilitates walking, so that fatigue is less likely to accumulate and is suitable for long-time running and walking. Generally, those having a rebound resilience of 50% or more have high rebound resilience. When a polyurethane foam is used for a shoe sole member, the rebound resilience is about 50 to 65%. Is required.

  Examples of such polyurethane foams having high rebound resilience include Patent Document 1 and Patent Document 2.

JP-A-11-171962 JP-A-2005-74735

  However, the polyurethane foams of Patent Documents 1 and 2 have insufficient tensile strength and tensile elongation for use with shoe sole members. If the tensile strength and tensile elongation are inferior, when used as a shoe sole member, cracks during molding, cracks or peeling during use are liable to occur, and there is a possibility that long-term use cannot be tolerated. Moreover, according to the present applicant, it was found that the higher the rebound resilience, the lower the tensile strength and tensile elongation.

  Then, an object of the present invention is to provide a polyurethane foam which is excellent in tensile strength and tensile elongation while having high rebound resilience.

  The present applicant has found that a polyurethane foam having high rebound resilience and excellent in tensile strength and tensile elongation can be obtained by using a specific polyol, and the present invention has been accomplished.

That is, the gist of the present invention is as follows:
(1) A polyurethane foam comprising a polyurethane raw material composition containing a polyol component, an isocyanate component, a foaming agent, a catalyst, and a foam stabilizer,
The polyol component is a polytetramethylene ether glycol (PTMG (I)) having a weight average molecular weight of more than 4000 and 7000 or less, an average number of functional groups of 2 or more and 3 or less, and an average hydroxyl value of 25 mg KOH / g or more and 80 mg KOH / g or less. Including
The polyurethane foam has a rebound resilience of 75% or more measured in accordance with JIS K 6255,
A polyurethane foam characterized by having a tensile strength of 1.0 MPa or more and a tensile elongation of 150% or more measured according to JIS K6251.
(2) The polyol component further comprises a polytetramethylene ether glycol (PTMG (II) having a weight average molecular weight of 1,000 to 4,000, an average number of functional groups of 2 to 3, and an average hydroxyl value of 80 mgKOH / g to 175 mgKOH / g. ))
The polyurethane foam according to the above (1), wherein the content of the PTMG (I) when the polyol component is 100 parts by mass is 30 parts by mass or more and 100 parts by mass or less.
(3) The polyurethane foam according to the above (1) or (2), wherein the polyurethane foam has a hardness of 40 or more and 65 or less measured using an Asker rubber hardness tester Model C according to JIS K 7312. .
(4) A test piece prepared by cutting the polyurethane foam into a cylindrical shape having a diameter of 29 mm and a thickness of 12.5 mm is prepared, and when a 5.1 kg weight collides against the test piece from a height of 50 mm. The polyurethane foam according to any one of (1) to (3), wherein a maximum impact load on the test piece is 1.0 kN or less.
(5) The polyurethane foam according to any one of the above (1) to (4), which is a molded article.
(6) A shoe sole member using the polyurethane foam according to any one of (1) to (5).

  ADVANTAGE OF THE INVENTION This invention can provide the polyurethane foam which is excellent in tensile strength and tensile elongation while having high rebound resilience, and a shoe sole member.

It is a figure for explaining the shape of the weight used by the drop impact test.

  The present invention is a polyurethane foam comprising a polyurethane raw material composition containing a polyol component, an isocyanate component, a foaming agent, a catalyst, and a foam stabilizer.

  As the polyol component of the present invention, polytetramethylene ether glycol (PTMG (I) having a weight average molecular weight of more than 4000 and 7000 or less, an average number of functional groups of 2 or more and 3 or less, and an average hydroxyl value of 25 mg KOH / g or more and 80 mg KOH / g or less. ))including.

If the weight average molecular weight of PTMG (I) is 4000 or less, or if the average hydroxyl value exceeds 80 mgKOH / g, the resulting polyurethane foam will have poor tensile strength and tensile elongation.
On the other hand, when the weight average molecular weight exceeds 7000 or the average hydroxyl value is less than 25 mgKOH / g, the viscosity of the polyol increases, and molding becomes difficult.

In the present invention, as the polyol component, PTMG having a different weight average molecular weight from PTMG (I) may be used singly or as a mixture of two or more.
Examples of PTMG other than PTMG (I) include polytetramethylene ether glycol (PTMG (PTMG) having a weight average molecular weight of 1,000 to 4,000, an average number of functional groups of 2 to 3, and an average hydroxyl value of 80 mgKOH / g to 175 mgKOH / g. II)) can be used.

When PTMG (I) and PTMG (II) are contained as the polyol component, the content of PTMG (I) is preferably 30 parts by mass or more and 100 parts by mass or less when the polyol component is 100 parts by mass.
When the content of PTMG (I) is less than 30 parts by mass, a polyurethane foam having high rebound resilience can be obtained, but the tensile strength and tensile elongation tend to be inferior. Also, the higher the content of PTMG (I), the better the resilience, tensile strength, and tensile elongation of the obtained polyurethane foam, but when the content of PTMG (I) exceeds 70 parts by mass, Slight stickiness and chipping of the foam surface were likely to occur, and the moldability was likely to be poor. Therefore, more preferably, the content of PTMG (I) is 30 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the polyol component.

  As the polyol component of the present invention, a polyol other than PTMG (I) and (II) may be added to such an extent that the effects of the present invention are not impaired. For example, polyether polyol, polyester polyol, and polymer polyol are mentioned.

  As the polyether polyol, for example, a polyether polyol obtained by ring-opening polymerization of an alkylene oxide is preferable. Examples of the alkylene oxide include propylene oxide (PO), ethylene oxide (EO), and butylene oxide. These may be used alone or in combination of two or more. Also, if necessary, polyether polyols to which polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose are added. May be.

  As the polyester polyol, for example, malonic acid, succinic acid, aromatic carboxylic acid such as adipic acid and aromatic carboxylic acid such as phthalic acid, and polycondensation with polyhydric alcohol such as ethylene glycol, diethylene glycol, propylene glycol and the like. The obtained one can be used.

  As the polymer polyol, those obtained by graft copolymerizing polyacrylonitrile, acrylonitrile-styrene copolymer, or the like with polyether polyol can be used.

In the present invention, a crosslinking agent may be added as necessary as a polyol component.
Examples of the crosslinking agent include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, tetramethylene ether glycol, glycerin, pentaerythritol, trimethylolpropane, monoethanolamine, diethanolamine, isopropanolamine, and amino. Alcohols such as ethylethanolamine, sucrose, sorbitol and glucose can be used. In particular, those having three or more functions are preferable.

  Examples of the isocyanate component of the present invention include aromatic isocyanates, aliphatic diisocyanates, alicyclic diisocyanates, isocyanate group-terminated prepolymers, and the like.

  More specifically, as an isocyanate component to be reacted with a polyol, diphenylmethane diisocyanate (4,4′-MDI), polymeric MDI (crude MDI), 2,4-tolylene diisocyanate (2,4-TDI), Aromatic isocyanates such as 2,6-tolylene diisocyanate (2,6-TDI), aliphatic diisocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate (HDI), alicyclics such as isophorone diisocyanate, hydrogenated TDI and hydrogenated MDI Group diisocyanates, or isocyanate group-terminated prepolymers obtained by prepolymerizing these, and the like, and these can be used alone or in combination of two or more.

  The isocyanate component is preferably a modified MDI. Specific examples of the modified MDI include polymeric (crude MDI), urethane modified, urea modified, allophanate modified, biuret modified, carbodiimide modified, uretonimine modified, uretdione modified, isocyanurate modified and the like. What is liquid at room temperature is suitable. It is preferable that a polymer (crude MDI) or a modified carbodiimide is selected as the modified MDI from the viewpoint that the molecular (crosslinked) structure after the reaction with the polyol component is excellent.

  As the modified MDI, those having an isocyanate group content of 25% by mass or more are preferably used. This is because the viscosity of the isocyanate component can be reduced because such a modified MDI is liquid at room temperature.

  If the modified MDI has an isocyanate group content of less than 25% by mass, the obtained polyurethane foam is difficult to foam, and defects such as chipping during molding tend to occur.

  Moreover, you may use together modified MDI and isocyanate group terminal prepolymer as an isocyanate component. When the modified MDI and the isocyanate group-terminated prepolymer are used in combination, the resilience of the obtained polyurethane foam tends to be improved. However, when the proportion of the isocyanate group-terminated prepolymer is too large, the foaming property deteriorates and the polyurethane foam surface becomes solid. Molding defects such as sticking and chipping occur. Therefore, the content ratio of the modified MDI to the isocyanate group-terminated prepolymer may be in the range of 100/0 to 30/70 in terms of the mass ratio of the modified MDI to the isocyanate group-terminated prepolymer (modified MDI / isocyanate group-terminated prepolymer). preferable.

  As the isocyanate group-terminated prepolymer, those having a number average molecular weight of 500 or more and 4000 or less, an average number of functional groups of 2 or more and 3 or less, and an isocyanate group content of 3 mass% or more and 10 mass% or less are preferably used. More preferably, the number average molecular weight is 500 or more and 2000 or less.

  When the isocyanate group-terminated prepolymer has a number average molecular weight of more than 4,000 and / or an isocyanate group content of less than 3% by mass, the obtained polyurethane foam is hard to foam and becomes too hard, and the viscosity is low. Large and easy to mix with other materials. When the isocyanate group-terminated prepolymer has a number average molecular weight of less than 500 and / or an isocyanate group content of more than 10% by mass, the obtained polyurethane foam tends to be easily foamed and becomes too soft. There is a possibility that hardness, rebound resilience, and shock absorbing properties cannot be obtained.

  The above isocyanate group-terminated prepolymer can be obtained by reacting a polyol and an isocyanate such that the isocyanate group (NCO group) becomes excessive.

  Examples of the polyol to be reacted with the isocyanate include those shown in the following (α), (β), and (γ).

(Α): polyether polyol, polyester polyol.
(Β): a polymer polyol (for example, a polyether polyol graft-copolymerized with polyacrylonitrile, acrylonitrile-styrene copolymer, or the like).
(Γ): Bifunctional one of the alcohols mentioned as examples of the crosslinking agent.

  With respect to the polyol to be reacted with the isocyanate, those described in the above (α), (β) and (γ) may be used alone or as a mixture of two or more. The polyol to be reacted with the isocyanate is preferably a polyether polyol among the above (α), (β) and (γ), and more preferably polytetramethylene ether glycol (hereinafter referred to as PTMG (III)). It is. The range of PTMG (III) includes the above-mentioned PTMG (I) and (II).

  The isocyanate for forming the isocyanate group-terminated prepolymer is preferably an aromatic isocyanate, an aliphatic diisocyanate, or an alicyclic diisocyanate, as described in the above-mentioned examples of the isocyanate component. , 4,4'-MDI are preferred.

  Therefore, as the isocyanate group-terminated prepolymer constituting the isocyanate component, a polymer obtained by reacting 4,4'-MDI with PTMG (III) is preferable. If the isocyanate group-terminated prepolymer is a prepolymer obtained by reacting 4,4′-MDI with PTMG (III), a urethane foam having high rebound resilience can be easily obtained because the PTMG portion has high crystallinity. Good compatibility when used in combination with modified MDI as an isocyanate component.

  The foam stabilizer of the present invention is not particularly limited as long as it can be used in urethane foam. For example, those containing a silicone compound having a polysiloxane chain and a polyoxyalkylene chain are preferably used. The polysiloxane chain and the polyoxyalkylene chain in the silicone compound may have a block type structure, or may have a graft type structure in which a polyoxyalkylene chain is grafted on a main chain polysiloxane chain. Good. Further, they may have a mixed structure. Examples of the polyoxyalkylene chain of the silicone compound include those composed of a single oxyalkylene group such as a polyoxyethylene chain and a polyoxypropylene chain, or an oxyethyleneoxypropylene block chain and an oxyethyleneoxypropylene random chain. And those composed of a plurality of types of oxyalkylene groups, and may be composed of a combination thereof.

  The amount of the silicone compound added as a foam stabilizer is preferably 0.5 parts by mass or more and 9 parts by mass or less based on 100 parts by mass of the above-mentioned polyol component. When the addition amount of the silicone compound is less than 0.5 parts by mass, the foam-regulating action is weak, the cell size of the obtained polyurethane foam is largely nonuniform, the rebound resilience is low, and it is difficult to obtain a desired impact absorption property. . When the addition amount of the silicone compound exceeds 9 parts by mass, not only the obtained polyurethane foam tends to be inferior in resilience but also bleed-out in which the foam stabilizer leaks out from the foam surface. There is a possibility that the adhesion of the resin may be hindered, which may result in poor handling. In particular, when the addition amount of the silicone compound exceeds 5 parts by mass, the desired resilience and shock absorption can be obtained, but the tackiness (stickiness) tends to occur to such an extent that there is no problem in use. In consideration of this point, the addition amount of the silicone compound is more preferably 0.5 part by mass or more and 5 parts by mass or less.

  As the foaming agent of the present invention, water (ion-exchanged water) can be preferably used. The amount of the foaming agent added to the polyurethane raw material composition is preferably 0.2 parts by mass or more and 0.8 parts by mass or less based on 100 parts by mass of the polyol component. When the addition amount is less than 0.2 parts by mass, foaming becomes insufficient, and molding failure tends to occur. When the addition amount exceeds 0.8 parts by mass, the obtained polyurethane foam hardly has high rebound resilience and is inferior in shock absorption.

  The catalyst of the present invention is not particularly limited as long as it can be used for producing a polyurethane foam. Examples of catalysts conventionally used include, for example, amine catalysts such as triethylenediamine and diethanolamine, and metal catalysts such as bismuth catalyst. The addition amount of the catalyst in the polyurethane raw material composition is preferably 0.1 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the polyol component described above.

  The polyurethane raw material composition for producing the polyurethane foam of the present invention, in addition to a polyol component, an isocyanate component, a foaming agent, a catalyst and a foam stabilizer, if necessary, may further contain other additives. Good. Other additives include additives generally usable in the production of polyurethane foam, such as plasticizers, fillers, antioxidants, defoamers, compatibilizers, colorants, stabilizers, and ultraviolet absorbers. be able to. The amounts of the other additives may be appropriately selected within a range that does not impair the effects of the present invention.

  The physical properties of the polyurethane foam of the present invention will be described below.

(Rebound resilience)
The polyurethane foam of the present invention preferably has a rebound resilience of 75% or more as measured in accordance with JIS K 6255. When the rebound resilience of the polyurethane foam is 75% or more, a shoe with high rebound resilience suitable as a sole member can be obtained.

[Tensile strength / tensile elongation]
The polyurethane foam of the present invention conforms to JIS K6251 and uses a dumbbell-shaped No. 2 test piece with a mark-to-line distance of 20 mm and a chuck-to-chuck distance of 70 mm, and the test piece at a speed of 200 mm / min by a tensile tester. The maximum tensile strength until the test piece breaks and the distance between the marked lines at the time of breakage are measured, and the tensile strength calculated by a predetermined formula is 1.0 MPa or more, and the tensile elongation is 150% or more. A polyurethane foam having these physical properties is unlikely to cause cracking during molding or cracking or peeling during use, can withstand long-term use, and is suitable as a shoe sole member.

〔hardness〕
The polyurethane foam of the present invention has a hardness of 40 or more and 65 or less according to JIS K 7312, measured using an Asker rubber hardness tester Model C. When the hardness of the polyurethane foam is 40 or more and 65 or less, it is possible to improve the comfort of shoes using the polyurethane foam as a sole member.

(Shock absorption)
The impact absorption of a polyurethane foam can be specified by the maximum impact load. In the polyurethane foam of the present invention, the maximum impact load is preferably 1.0 kN or less. The maximum impact load can be specified by the following drop impact test. The smaller the value of the maximum impact load, the more the impact is absorbed. When the maximum impact load on the polyurethane foam is 1.0 kN or less, a polyurethane foam having an impact-absorbing property that can be used as a shoe sole member is obtained.

(Drop impact test)
A polyurethane foam formed so as to have a thickness of 12.5 mm is prepared and used as a test piece. A 5.1 kg weight is impacted against a polyurethane foam test piece from a height of 50 mm. A bullet-shaped weight W as shown in FIG. 1 may be used as the weight. Then, the maximum impact load at that time is specified. The maximum impact load can be measured using, for example, dynapup GRC8200 (trade name, manufactured by Instron).

〔density〕
In the polyurethane foam of the present invention, the apparent density of the polyurethane foam measured according to JIS K7222 is 0.35 g / cm ³ or more and 0.60 g / cm ³ or less.

  The polyurethane foam can be formed by a conventional molding method such as molding, injection molding, or extrusion molding of the above-mentioned polyurethane raw material composition, but it is preferable that the polyurethane foam be reacted by molding. Here, the mold molding is a method of injecting the above-mentioned polyurethane raw material (stock solution) into a mold (molding die), foaming and hardening in the mold, and then removing the mold to obtain a foam.

  Since the polyurethane foam is manufactured by molding the polyurethane raw material composition, the cell size can be made uniform and fine due to the compression effect at the time of foaming. When the polyurethane raw material composition is molded, the density of the obtained polyurethane foam can be easily adjusted by the injection amount of the polyurethane raw material composition with respect to the volume in the mold.

  Since the polyurethane foam of the present invention has excellent tensile strength and tensile elongation while having high rebound resilience, it can be suitably used, for example, as a shoe sole member. When used as a sole member, the polyurethane foam can be used for any of an outsole, a midsole, and an insole. When a polyurethane foam is used for a sole member, not only is the polyurethane foam of the present invention provided on the entire sole of the shoe, but also a recess is formed in a midsole formed of another material, and the polyurethane foam of the present invention is formed there. Partial arrangement, such as insertion, is also possible. Further, as the shoe sole, the polyurethane foam of the present invention may be used for the midsole, and an outsole made of a rubber material having anti-slip properties may be laminated on the ground surface side. In that case, the outsole may be arranged at an arbitrary position on the midsole ground plane side, or the outsole may be partially cut out to partially expose the ground plane side midsole. Good.

  The polyurethane foam of the present invention can be suitably used for applications requiring impact absorption, rebound resilience, etc., such as inside a helmet, a protector, a cushioning material for vehicles, flooring materials, etc., in addition to sole members.

Examples 1 to 12, Comparative Examples 1 to 5
A mold having a predetermined shape is prepared, and as shown in Tables 1 and 2, a polyol component, an isocyanate component, a catalyst, a foaming agent, and a foam stabilizer are mixed with each other by stirring using a screw. Was injected. The amount of the polyurethane raw material composition injected into the mold was adjusted so that the density became 0.45 ± 0.05 g / cm ³ . The polyurethane raw material composition is formed by mixing a polyol component, an isocyanate component, a catalyst, a foaming agent, and a foam stabilizer using a screw. After the polyurethane raw material composition was injected into the mold, the polyurethane raw material composition was reacted at a mold temperature of 40 ° C. After the reaction, the mold was released to obtain a polyurethane foam. The units of numerical values indicating the blending of the materials in Tables 1 and 2 are parts by mass.

  The polyol component, isocyanate component, catalyst, foaming agent, and foam stabilizer in Tables 1 and 2 are as shown below.

(Polyol component)
Polyol (I)
Polyol 1: polytetramethylene ether glycol (weight average molecular weight 4644, hydroxyl value 57.2 mg KOH / g, average number of functional groups 2)
Polyol 2: polytetramethylene ether glycol (weight average molecular weight 6861, hydroxyl value 39.1 mg KOH / g, average number of functional groups 2)
Polyol (II)
Polyol 3: polytetramethylene ether glycol (weight average molecular weight 1993, hydroxyl value 113.1 mgKOH / g, average number of functional groups 2)
Polyol 4: polytetramethylene ether glycol (weight average molecular weight 2000, hydroxyl value 57 mgKOH / g, average number of functional groups 2)
Polyol 5: polytetramethylene ether glycol (weight average molecular weight 1000, hydroxyl value 113 mgKOH / g, average number of functional groups 2)
Polyol 6: polytetramethylene ether glycol (weight average molecular weight 1050, hydroxyl value 170.2 mg KOH / g, average number of functional groups 2)
[Catalyst] Triethylenediamine (manufactured by Tosoh Corporation, trade name TEDA-L33)
[Foam stabilizer] Silicone foam stabilizer (trade name "SZ3601" manufactured by Dow Corning Toray)
[Blowing agent] Ion exchange water [Isocyanate component]
Modified MDI: modified carbodiimide (average number of functional groups: 2, isocyanate group content: 29.0%)
Isocyanate terminal group prepolymer: Prepolymer obtained by reacting polytetramethylene ether glycol with 4,4′-MDI (number average molecular weight: 1,000, average number of functional groups: 2, isocyanate group content: 7.99%)

With respect to the polyurethane foams obtained in Examples 1 to 12 and Comparative Examples 1 to 4, the hardness of the polyurethane foam was measured using an Asker rubber hardness tester Model C in accordance with JIS K 7312. Further, test pieces were prepared by appropriately cutting the polyurethane foams obtained in Examples 1 to 12 and Comparative Examples 1 to 4, and the following measurements were performed using the test pieces. The results are as shown in Tables 1 and 2.
In Comparative Example 5, each measurement was not performed because molding was impossible.

(Apparent density)
A rectangular parallelepiped having a length of 15 mm, a width of 15 mm, and a thickness of 10 mm is cut out from the polyurethane foam to obtain a test piece for density measurement, and the apparent density (g / cm ³ ) is measured using the test piece for density measurement according to JIS K7222. Was.

(Rebound resilience)
A sample having a diameter of 29 mm and a thickness of 12.5 mm was cut out from the polyurethane foam to prepare a test piece for measuring rebound resilience, and the rebound resilience (%) was measured using the test piece for measuring resilience in accordance with JIS K 6255. Was.

(Tensile strength / tensile elongation)
According to JIS K 6251, a dumbbell-shaped No. 2 shape was cut out from a polyurethane foam to obtain a test piece. The test piece was pulled at a speed of 200 mm / min with a tensile tester at a distance of 20 mm between marks and a distance of 70 mm between chucks. The maximum tensile strength until the test piece was broken and the distance between the marked lines at the time of the break were measured, and the tensile strength (MPa) and the tensile elongation (%) were calculated by a predetermined formula.

(Maximum impact load)
The polyurethane foam was cut into a rectangular parallelepiped shape having a length of 70 mm, a width of 60 mm and a thickness of 12.5 mm to obtain a test piece for measuring an impact load. The maximum impact load was measured by a drop impact test using the test piece for measuring an impact load. In the drop impact test, using a dynamup GRC8200 (manufactured by Instron), a shell-shaped weight w (iron, 5.1 kg) as shown in FIG. 1 collides with a test piece for measuring an impact load from a height of 50 mm. It was carried out by specifying the maximum impact load (kN) at the time of the application.

(Moldability)
The polyurethane foam after demolding was evaluated based on the following criteria by touch and visual observation.

：: Good surface without stickiness and chipping on the surface.
Δ: Slight stickiness and chipping of the surface occur, but there is no problem as a product.
X: The surface was sticky and chipped, and could not be used as a product (molding impossible).

  According to Examples 1 to 12, it was possible to obtain the polyurethane foam of the present invention having excellent tensile strength and tensile elongation while having a high rebound resilience of 75% or more. Further, from Examples 3 to 7, by using together a specific PTMG having a different weight average molecular weight, one having excellent moldability was obtained.

On the other hand, Comparative Examples 1 to 5 are examples using a material other than PTMG used in the present invention, and a high rebound resilience is not obtained, or even if high rebound resilience, the tensile strength and tensile elongation are inferior. It became.

W weight

Claims (6)

Polyurethane foam comprising a polyurethane raw material composition containing a polyol component, an isocyanate component, a foaming agent, a catalyst and a foam stabilizer,
The polyol component is a polytetramethylene ether glycol (PTMG (I)) having a weight average molecular weight of more than 4000 and 7000 or less, an average number of functional groups of 2 or more and 3 or less, and an average hydroxyl value of 25 mg KOH / g or more and 80 mg KOH / g or less. Including
The polyurethane foam has a rebound resilience of 75% or more measured in accordance with JIS K 6255,
A polyurethane foam characterized by having a tensile strength of 1.0 MPa or more and a tensile elongation of 150% or more measured according to JIS K6251. The polyol component further comprises polytetramethylene ether glycol (PTMG (II)) having a weight average molecular weight of 1,000 to 4,000, an average number of functional groups of 2 to 3, and an average hydroxyl value of 80 mgKOH / g to 175 mgKOH / g. Including
The polyurethane foam according to claim 1, wherein the content of the PTMG (I) when the polyol component is 100 parts by mass is 30 parts by mass or more and 100 parts by mass or less. 3. The polyurethane foam according to claim 1, wherein the polyurethane foam has a hardness of 40 or more and 65 or less according to JIS K 7312 measured using an Asker rubber hardness tester type C. 4.   A test piece was prepared by cutting the polyurethane foam into a cylindrical shape having a diameter of 29 mm and a thickness of 12.5 mm. When a 5.1 kg weight was caused to collide with the test piece from a height of 50 mm, the test piece was cut. The polyurethane foam according to any one of claims 1 to 3, wherein a maximum impact load on the polyurethane foam is 1.0 kN or less.   The polyurethane foam according to any one of claims 1 to 4, which is a molded article.   A shoe sole member using the polyurethane foam according to any one of claims 1 to 5.

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