JP2003306522A - Foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam having sufficient strength and combining soft and good touch and reduced resilience. <P>SOLUTION: The foam has a density of 0.1 g/cm<SP>3</SP>or higher, a storage elastic modulus, obtained by the dynamic viscoelasticity at a frequency of 10 Hz and 25°C of 5-20 MPa and a tanδ of 0.16-0.5. A sole having the foam and a shoe having the sole are also provided. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to foams.
More specifically, for example, the present invention relates to a foam that can be suitably used as a cushioning material for shoe soles, automobiles and other vehicles, furniture, bedding, and the like.

[0002]

BACKGROUND OF THE INVENTION Foams typified by polyurethane foams are widely used in various fields. Generally, the properties required of foams differ depending on the purpose of use and the site of use. From the viewpoint of safety, wearing comfort and tactile sensation, the development of a polyurethane foam having sufficient strength, soft and good feel, and low impact resilience has been advanced. However, there has not been obtained a foam having sufficient strength and satisfying both soft and good feeling and low impact resilience at the same time.

For example, in the field of polyurethane foams, low-resilience polyurethane foams having good elongation and tensile strength are known (Japanese Unexamined Patent Publication No. 2002-47330). However, although it satisfies the requirements of high strength and low resilience, it has a drawback in that it has a high storage elastic modulus in terms of dynamic viscoelasticity and is soft and does not have a good feel.

When the dynamic viscoelasticity is measured at a frequency of 10 Hz as a polyurethane foam having a good low resilience in a wide temperature range, the storage elastic modulus at a temperature of 0 ° C. or higher is 5 MPa or less. A polyurethane foam has been proposed (Japanese Patent Laid-Open No. 11-286566). However, this polyurethane foam has the drawback of not having sufficient hardness and strength at room temperature.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a foam having sufficient strength, softness, good feel and low impact resilience at the same time.

[0006]

That is, according to the present invention, the density is 0.1 g / cm ³ or more, and the frequency is 10 Hz, 25
Storage elastic modulus obtained from dynamic viscoelasticity at ℃ is 5 to 2
The present invention relates to a foam having a pressure of 0 MPa and a tan δ of 0.16 to 0.5, a shoe and a sole having the foam.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The foam of the present invention is manufactured according to JIS K
Based on the test method specified in 7198, frequency 10 Hz,
Storage elastic modulus obtained from dynamic viscoelasticity measured at 25 ° C. is 5 to 20 MPa, and tan δ is 0.1.
Since it is from 6 to 0.5, it exhibits an excellent effect that it has sufficient strength and is soft and has a good feel and low impact resilience at the same time.

The inventors of the present invention have conducted extensive studies to obtain a foam which exhibits the excellent effect of having a soft and good feel and low impact resilience at the same time. It has been found that the storage elastic modulus at 25 ° C. and tan δ, which is the ratio of the loss elastic modulus to the storage elastic modulus, have a correlation between the feeling felt by a person and the low impact resilience. That is, when the tactile sensation was evaluated by the touch finger and the storage elastic modulus, a foam having sufficient strength, soft and good feel, and low impact resilience in a temperature range of -5 ° C to 40 ° C was obtained. 25 can be obtained
It was found that the storage elastic modulus (E ′) and tan δ when measured at a temperature of 10 ° C., a frequency of 10 Hz, and a temperature rising rate of 2 ° C./min were within a specific range. Therefore, the foam of the present invention has a specific storage modulus and a specific t.
Appropriately defined by an δ.

The temperature of 25 ° C. and the frequency of 10 Hz, which are the conditions for measuring the dynamic viscoelasticity, are such that the average value of the temperature felt by humans in daily life is about 25 ° C., and the foam is used as the sole of the shoe. However, the natural frequency of the shoe sole is set to 5 to 10 Hz when the person wearing the shoe having the shoe sole walks, runs lightly, or runs at full speed.

The term "soft feel" as used in the present specification means that when the foam is pressed directly at the tip of the fingernail or in the vicinity of the fingernail or at the fingertip-printed portion, and it is bent, it does not feel hard like a stone. It means that the foam is crushed, but it feels so comfortable that it does not feel a bottom.

The "low impact resilience" referred to in the present specification is measured at a temperature of 25 ° C. using a foam having a diameter of 32 mm and a thickness of 10 mm based on the impact resilience test specified in JIS K6301. The impact resilience is 35% or less.

Dynamic viscoelasticity is a combined behavior of viscosity and elasticity when a steady sinusoidal strain is applied to a foam. The dynamic viscoelasticity is obtained by measuring the stress with respect to the strain or the strain with respect to the stress.

The complex elastic modulus is a value of the ratio between the maximum stress and the maximum strain in the dynamic viscoelasticity, and is obtained by a complex number operation as a vector. The real part of the complex elastic modulus is the storage elastic modulus (dynamic storage elastic modulus) that indicates the magnitude of the in-phase stress component when the sinusoidal wave distortion of the characteristic frequency is applied. The loss elastic modulus (dynamic loss elastic modulus) is the magnitude of the stress component whose phase advances by π / 2 from the strain when a sine wave strain is applied.

Tan δ is also called loss tangent,
Formula: [tan δ] = [loss elastic modulus] / [storage elastic modulus] Tan δ is used as a measure of the energy absorption of foams. When measuring the dynamic viscoelasticity temperature change, the storage frequency, loss elastic modulus, and tan δ are calculated as a function of temperature by keeping the frequency constant during measurement, and the storage elastic modulus is dispersed and the loss elastic modulus is absorbed. , Transition from the glass state of the foam used for measurement to the rubber state,
It is possible to know the relaxation phenomenon of impact energy given from the outside.

Storage elastic modulus (E ') is 5 to 20 MPa, preferably 5 to 15 MPa, more preferably 6 to 13 MPa.
When it is in the range of a, a foam having sufficient strength and being soft and having a good feel can be obtained. That is, when the storage elastic modulus (E ′) is smaller than the lower limit value, not only the foam is too soft and does not have a good feel, but also the mechanical strength is lowered and the storage elastic modulus (E ′) is also decreased. When the value of () is larger than the upper limit, the foam becomes hard and does not have a soft feel.

Tan δ is 0.16 to 0.5, preferably 0.18 to 0.25, and more preferably 0.19 to 0.2.
When it is within the range of 3, a foamed body excellent in low impact resilience and shape restoring property can be obtained. That is, when tan δ is smaller than the lower limit value, the low rebound resilience when an external force is applied becomes insufficient, and when tan δ is larger than the upper limit value, when external force is applied and deformed, It becomes difficult to restore the original shape, and it becomes difficult to obtain a soft and good feeling.

The impact resilience of the foam is JIS K 63
Based on the measurement method described in 01, thickness 10 mm, diameter 32
mm when measured at a temperature of 25 ° C. using a foam, from the viewpoint of absorbing impact energy given from the outside,
It is preferably 35% or less, more preferably 32% or less, still more preferably 30% or less. Also, from the viewpoint of easily restoring the original shape when deformed due to external force,
It is preferably 10% or more, more preferably 12% or more, still more preferably 15% or more. From these viewpoints, the impact resilience of the foam is preferably 10 to 35%, more preferably 12 to 32%, and further preferably 15 to 30%.

The tensile strength of the foam is JIS K
Based on the measurement method described in 6301, when using a foam having a thickness of 10 mm and a diameter of 32 mm at a temperature of 25 ° C., from the viewpoint of obtaining sufficient mechanical strength and durability, preferably 10 kg / cm ² (0 0.98 MPa) or more, more preferably 12 kg / cm ² (1.18 MPa) or more, still more preferably 15 kg / cm ² (1.47 MPa) or more.

The raw materials constituting the foam of the present invention include self-foaming polyurethane and the like, rubber, polyvinyl chloride, ethylene-vinyl acetate copolymer,
Examples thereof include olefin resins and styrene resins. Rubber, polyvinyl chloride, ethylene-vinyl acetate copolymer,
When an olefin resin, a styrene resin, or the like is used, a method of foaming by using pre-expanded particles obtained by pre-expanding these resins, a method of impregnating the resin with a foaming agent, and then performing in-mold foam molding, etc. Can be adopted.

The case where the foam of the present invention is made of a typical polyurethane foam will be described below.

The polyurethane foam having a predetermined storage elastic modulus and tan δ of the present invention is (a) a polyol,
(B) chain extender, (c) polyisocyanate compound,
It can be obtained by appropriately adjusting (d) the catalyst and (e) the foaming agent, mixing and reacting them, and controlling the ratio of the soft segment and the hard segment forming the polyurethane foam.

The polyurethane foam is composed of a soft segment composed of a polyol and a hard segment composed of an aggregate having a urethane bond or a urea bond having a high bond energy. The behavior of dynamic viscoelasticity due to this hard segment affects the storage elastic modulus and tan δ in the temperature range of −5 to 40 ° C., and therefore it is important to control this behavior.

The polyol is selected from the group consisting of a polyether polyol having two or more hydroxyl groups (hereinafter referred to as polyether polyol), a polymer polyol based on polyether polyol (hereinafter referred to as polymer polyol), and a polyester polyol. At least one kind is preferable.

As the polyether polyol, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, glycerin, trimethylolpropane, 1,
Examples thereof include polyether polyols and polyoxytetramethylene glycol obtained by addition-polymerizing alkylene oxides with polyhydric alcohols such as 2,6-hexanetriol and pentaerythritol.

As a typical example of the polyether polyol, a polyoxypropylene polyol having ethylene oxide added to a terminal hydroxyl group of polyoxypropylene polyol and having a molecular weight of 1500 or more per hydroxyl group, and obtained by ring-opening polymerization of tetrahydrofuran. Molecular weight 1
000 or more of polyoxytetramethylene glycol and a mixture thereof are included.

Typical examples of the polymer polyol include those in which polymer fine particles obtained by polymerizing a polymerizable unsaturated group-containing monomer are dispersed in a polyether polyol. This is, for example, a method of mixing and dispersing polymer fine particles obtained by polymerizing a polymerizable unsaturated group-containing monomer and a polyether polyol, the polymerizable unsaturated group-containing monomer in the polyether polyol. By polymerizing, polymer fine particles obtained from the polymerizable unsaturated group-containing monomer can be produced by a method such as a method of dispersing in a production method polyether polyol. Among these methods, the latter method is preferable because a polymer polyol in which polymer particles are uniformly dispersed in the polyether polyol can be easily obtained.

Examples of the polymerizable unsaturated group-containing monomer include styrene; acrylonitrile; alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms such as methyl methacrylate, ethyl methacrylate and butyl methacrylate; glycidyl methacrylate; methyl acrylate, ethyl acrylate and butyl. Examples thereof include alkyl acrylates having an alkyl group having 1 to 4 carbon atoms; glycidyl acrylate, and the like. These monomers can be used alone or in combination of two or more.

As the polyester polyol, for example, ethylene glycol, propylene glycol, 1,
It is a condensate of a polyhydric alcohol such as 4-butanediol, diethylene glycol, neopentyl glycol and trimethylolpropane with a polybasic acid such as phthalic acid, maleic acid, malonic acid, succinic acid, adipic acid and terephthalic acid. , Those having a hydroxyl group at the terminal, and the like.

In order to obtain a polyurethane foam satisfying the dynamic viscoelasticity conditions of the present invention and having sufficient strength, desired storage elastic modulus and tan δ, the molecular weight of the bifunctional polyol or the trifunctional polyol and the weight ratio of both polyols are used. Can be adjusted.

Incidentally, the "dynamic viscoelastic condition" referred to in the present specification.
Means that the storage elastic modulus is 5 to 20 MPa and tan δ is 0.16 to 0.5.

For example, when the strength, storage elastic modulus and tan δ are controlled only by the bifunctional polyol, a low molecular weight bifunctional polyol is used so that the soft segment is easily affected by the hard segment and the degree of freedom is reduced. It is preferable to improve the crystallinity of the entire resin. By such an operation, the dynamic viscoelastic condition can be satisfied.

When the bifunctional polyol and the trifunctional polyol are used in combination, the kind of the bifunctional polyol is kept constant and the molecular weight of the trifunctional polyol and the weight ratio of the bifunctional polyol and the trifunctional polyol are controlled to obtain a hard resin. It is preferable to enhance the crystallinity of the soft segment portion near the segment. By controlling the molecular weight of the trifunctional polyol and the weight ratio of the bifunctional polyol to the trifunctional polyol in this way, the dynamic viscoelastic condition can be satisfied.

The molecular weights of the bifunctional polyol and the trifunctional polyol, and the weight ratio of the bifunctional polyol to the trifunctional polyol are important factors for obtaining a foam having sufficient strength.

The bifunctional polyol preferably has an average number of functional groups of 1.5 to 2.5 and a number average molecular weight of 1,000 to 5,000 from the viewpoint of imparting sufficient strength.

The trifunctional polyol improves the initial reactivity,
From the viewpoint of ensuring the dimensional stability of the molded product and shortening the demolding time, the average functional group number is 2.5 to 3.5 and the number average molecular weight is 20.
It is preferable to have 00 to 10,000.

The weight ratio of bifunctional polyol / trifunctional polyol is preferably 40/60 to 80/20 from the viewpoint of ensuring sufficient strength and dimensional stability of the molded product.

When a polyether polyol is used as the bifunctional polyol, the average number of functional groups is 1.5 to
From the viewpoint of imparting sufficient strength, it is preferably 2.5 and the number average molecular weight is 1500 to 4500. When a polyester polyol is used as the bifunctional polyol, the average number of functional groups is 1.5 to 2.5 and the number average molecular weight is 1,000 to 2,500 to impart sufficient strength and ensure liquidity. From the viewpoint of

When a polyether polyol is used as the trifunctional polyol, the average number of functional groups is 2.5 to 3.5 and the number average molecule 0 is 2000 to 80.
A value of 00 is preferable from the viewpoint of dimensional stability of the molded product. When polyester polyol is used as the trifunctional polyol, the average number of functional groups is 2.5 to 3.5, and the number average molecular weight is 2000 to 4000 in order to secure dimensional stability and liquidity of the molded product. It is preferable from the viewpoint.

Among these polyols, polyether polyols are preferable from the viewpoint of achieving both soft and good feel and low impact resilience.

The chain extender has a number average molecular weight of 100.
A compound having a low molecular weight of 0 or less and having two or more active hydrogens in the molecule can be used.

Typical examples of the chain extender are ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, trimethylolpropane and glycerin. , Pentaerythritol,
Diglycerin, dextrose, sorbitol, and other polyhydric alcohols, ethylenediamine, hexamethylenediamine, and other aliphatic polyamines, aromatic polyvalent amines, diethanolamine, triethanolamine, diisopropanolamine, and other alkanolamines, and their modified products Etc. These may be used alone or in combination of two or more.

A suitable chain extender has a number average molecular weight of 100.
0 or less ethylene glycol, diethylene glycol,
It is at least one selected from the group consisting of 1,4-butanediol pentaerythritol and their modified organisms.

Polyurethane foams satisfying the dynamic viscoelastic conditions and having sufficient strength, desired storage modulus and tan δ can be obtained by adjusting the amount of a low molecular weight chain extender.

Generally, the chain extender reacts with the isocyanate component to form a strong hard segment. The dynamic viscoelastic behavior resulting from this hard segment directly affects the dynamic viscoelastic condition. Increasing the amount of the chain extender increases the size and the number of hard segments, so it is -5 to 4
It is presumed that the storage modulus and tan δ are increased in the temperature range of 0 ° C.

However, when the amount of the chain extender is too large, the hardness of the urethane foam, the storage elastic modulus increase and the feel deteriorate, so that a foam having a soft and good feel is obtained. The amount of the chain extender is preferably 3 to 20 parts by weight based on 100 parts by weight of the polyol.

Representative examples of polyisocyanate compounds include isocyanate prepolymers.

The isocyanate prepolymer is obtained by stirring and reacting a polyisocyanate monomer and a polyol in the presence of an excess of the polyisocyanate monomer by a conventional method.

Specific examples of the polyisocyanate monomer include tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate. , 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5- Examples thereof include polyisocyanate compounds such as naphthalene diisocyanate, and modified products thereof, such as carbodiimide modified products. These can be used alone or in combination of two or more. Among these, it is preferable to use 4,4′-diphenylmethane diisocyanate alone or to use the 4,4′-diphenylmethane diisocyanate and its carbodiimide modified product in combination.

When preparing the isocyanate prepolymer, additives may be added if necessary.

The additives include, for example, additives that are optionally used when preparing a polyester polyol, and acidic gases such as hydrogen chloride gas and sulfurous acid gas in order to prevent the isocyanate prepolymer from self-polymerizing. Acid chlorides such as acetyl chloride, benzoyl chloride and isophthalic acid chloride, and isocyanate self-polymerization inhibitors such as phosphoric acid, phosphoric acid compounds such as monoethyl phosphate, diethyl phosphate and the like can be used. These additives can be used alone or in admixture of two or more.

NCO% of isocyanate prepolymer
Is preferably 10% or more, more preferably 15% or more, in order to prevent the viscosity from becoming high and making molding in a low-pressure foaming machine difficult, and the viscosity being low, the metering accuracy of the foaming machine becomes low. In order to avoid lowering, it is preferably 25% or less, more preferably 22% or less, further preferably
20% or less.

Since the isocyanate prepolymer is liquid at 15 ° C. or higher and can be discharged even at a low pressure,
For example, it can be used for the production of polyurethane foam without any problem even at a molding temperature of 40 to 50 ° C.

The NCO% of the polyisocyanate compound is
From the viewpoint of preventing increase in liquid viscosity and storage stability of liquid, 10 to 10
25% is preferable. As the polyisocyanate monomer constituting the polyisocyanate compound, 4,4-diphenylmethane diisocyanate is preferable from the viewpoint of obtaining a foam having sufficient mechanical strength.

As the catalyst, for example, TEDA [1,4
-Diazabicyclo- [2.2.2] -octane], N, N, N '
, N′-tetramethylhexamethylenediamine, N,
N, N ′, N′-tetramethylpropylenediamine,
N, N, N ', N', N "-pentamethyldiethylenetriamine, trimethylaminoethylpiperazine, N, N
-Dimethylcyclohexylamine, N, N-dimethylbenzylamine, N-methylmophorin, N-ethylmophorin, triethylamine, tributylamine, bis (dimethylaminoalkyl) piperazine, N, N, N ', N'
-Tetramethylethylenediamine, N, N-diethylbenzylamine, bis (N, N-diethylaminoethyl)
Adipate, N, N, N ', N'-tetramethyl-1,
3-butanediamine, N, N-dimethyl-β-phenylethylamine, 1,2-dimethylimidazole, 2-methylimidazole and the like can be mentioned, and these catalysts may be used alone or in combination of two or more kinds. You may use. Among the catalysts, tertiary amines are preferable from the viewpoint of improving the reaction rate.

As a catalyst other than the tertiary amine, for example, an organometallic compound such as dibutyltin dilaurate, stannous oleate, cobalt naphthenate, lead naphthenate can be used.

As the foaming agent, water is an essential component, and hydrocarbons, chlorofluorocarbons, hydrogenated fluorocarbons and the like may coexist. From the viewpoint of avoiding the problem of depletion of the ozone layer of the earth, it is preferable to use water alone as the foaming agent.

When water is used as the foaming agent, generally,
Water reacts with the polyisocyanate compound to form strong hard segments. The dynamic viscoelastic behavior resulting from this hard segment directly affects the dynamic viscoelastic condition. Since increasing the amount of water increases the size and number of hard segments, ta is increased in the temperature range of -5 to 40 ° C.
It is presumed that the value of nδ is increased. However,
The density of the polyurethane foam is lowered due to the influence of carbon dioxide gas generated by the reaction between the isocyanate and water. Therefore, the amount of water is important. From this viewpoint, the amount of water as a foaming agent is preferably 0.3 to 2 parts by weight, more preferably 0.5 to 2 parts by weight with respect to 100 parts by weight of the polyol.
1.8 parts by weight, more preferably 0.9 to 1.6 parts by weight.

In the present invention, a silicone type foam stabilizer, a cross-linking agent, a pigment, an antioxidant, an anti-yellowing agent or the like can be used as an additive.

The polyol, the chain extender, the polyisocyanate compound, the catalyst and the foaming agent are appropriately adjusted and mixed and reacted to control the degree of the soft segment and the hard segment forming the polyurethane foam. It is possible to obtain a polyurethane foam that satisfies the dynamic viscoelastic conditions and has sufficient strength, a desired storage elastic modulus, and tan δ.

When reacting the polyol and the polyisocyanate compound, the ratio of the two is preferably adjusted so that the isocyanate index is 80 to 110, more preferably 85 to 105, and particularly preferably 90 to 100.

As a method for producing a polyurethane foam,
For example, a polyol, a chain extender, a catalyst, a foaming agent, an additive and the like are mixed in advance, and the polyol component and the polyisocyanate compound that have been stirred are mixed and stirred by a molding machine,
Examples thereof include a method of injecting into a molding die and foaming. More specifically, for example, a polyol component is mixed and stirred using a tank or the like, and the temperature is usually adjusted to about 40 ° C., and then a foaming machine such as an automatic mixing injection type foaming machine or an automatic mixing type injection foaming machine. And a method of reacting with a polyisocyanate compound to foam.

In order to obtain a polyurethane foam satisfying the dynamic viscoelasticity condition and having a sufficient strength, a desired storage elastic modulus and tan δ, the density of the polyurethane foam is 0.1 g / cm ³ or more, preferably 0.2-0.6
g / cm ³ , more preferably 0.25 to 0.45 g / c
m is ^3.

Suitable uses of the foam of the present invention include soles of men's shoes, sports shoes and the like. Generally, the sole is an outsole used for sandals, men's shoes, etc.
It is classified as a midsole used for sports shoes. In the present invention, among these, midsole is particularly preferable in consideration of the effect of foaming.

The shoe of the present invention can usually be manufactured by integrating the shoe body (instep or the like) and the sole. The shoe body is a part that wraps around the instep of the foot, and may be made of any material or shape.

The case where the foam is a polyurethane foam has been described above. The density is 0.1 g / cm ³ or more, and the storage modulus obtained from the dynamic viscoelasticity at a frequency of 10 Hz and 25 ° C. is 5. The method for producing a foam having a pressure of ˜20 MPa and a tan δ of 0.16 to 0.5 varies depending on the type of the foam and the like. Therefore, these properties are preferably adjusted appropriately according to the type of the foam.

In the following, in the case where the foam of the present invention is polyurethane foam, the method for producing the foam having the above-mentioned properties will be described in more detail.

[0067]

EXAMPLES Examples 1 to 6 and Comparative Examples 1 to 5 A polyol, a chain extender,
A catalyst, a foaming agent (water), a foam stabilizer and a white pigment were mixed to prepare a polyol component.

The mixing ratio of the polyol component and the polyisocyanate is based on the formula: [isocyanate index] = [amount of isocyanate actually used) / (amount of isocyanate stoichiometrically equivalent to polyol) × 100 The isocyanate index was adjusted so as to be the value shown in Table 1.

The polyol component and the polyisocyanate were charged into an automatic mixing type injection foaming machine [manufactured by Polyurethane Engineering Co., model: MU-203S, model number: 6-018] and mixed at a temperature of 35 to 45 ° C. to obtain the mixture. The mixture is charged into a mold having a mold temperature of 45 to 55 ° C. (the inner surface is coated with a silicone release agent), and foamed under the following molding conditions.
A test sheet made of polyurethane foam of mm × 100 mm × 300 mm was prepared.

[Molding conditions] ・ Reactivity: Cream time 5 ~ 15 seconds -Demolding time: 5.5 to 6.5 minutes

The abbreviations of the components used in each Example and each Comparative Example have the following meanings.

[Polyol] PO1: polypropylene glycol [manufactured by Asahi Glass Urethane Co., Ltd., trade name: Preminol 5005, number of functional groups:
2, hydroxyl value: 28 mgKOH / g, number average molecular weight: 4
000] PO2: polypropylene glycol [Asahi Glass Urethane Co., Ltd., trade name: EXCENOL 540, number of functional groups:
2, hydroxyl value: 56 mg KOH / g, number average molecular weight: 2
000]

PO3: polypropylene triol [manufactured by Asahi Glass Urethane Co., Ltd., trade name: EXCENOL 820, number of functional groups: 3, hydroxyl value: 34 mgKOH / g, number average molecular weight: 4900] PO4: polyester polyol (raw material monomer: ethylene glycol, 1,4-butanediol and adipic acid, ethylene glycol / 1,4 butanediol (weight ratio) = 1/1, number of functional groups: 2, hydroxyl value: 86 mg KO
H / g, number average molecular weight: 1300)

[Polyisocyanate] PI1: manufactured by Kao Corporation, trade name: Ediform B-6
106M (NCO%: 16.0%, isocyanate used for isocyanate prepolymer: 4,4′-diphenylmethane diisocyanate) PI2: manufactured by Kao Corporation, trade name: EDIFORM Foam B-2
009 (NCO%: 18.5%, isocyanate used in isocyanate prepolymer: 4,4′-diphenylmethane diisocyanate)

[Chain extender] CE1: ethylene glycol CE2: diethylene glycol

[Catalyst] Triethylenediamine

[Foam Stabilizer] Toray Dow Corning Silicone Co., Ltd., trade name:
SRX-253 [white pigment] Dainichiseika Kogyo KK, trade name: FTR White

[0078]

[Table 1]

The physical properties of the produced test sheet were examined according to the following methods. The results are shown in Table 2.

(1) Storage elastic modulus and tan δ The dynamic viscoelasticity test is based on the test method of JIS K 7198, and a rectangular parallelepiped sample piece having a length of 30 mm and a cross section of 5 mm × 10 mm cut out from a test sheet prepared. Using a dynamic viscoelasticity measuring device DVA-225 manufactured by IT Measurement and Control Co., Ltd., a temperature rising rate of 2 ° C./min and a frequency of 1
It was measured at 0 Hz. Start cooling after cooling minus 10
It started at 0 ° C. From the obtained data, the storage elastic modulus (E ′) at 25 ° C. and tan δ were determined.

(2) The density test sheet (100 mm × 300 mm × 10 mm) was weighed and divided by the volume of 300 cm ³ to measure.

(3) Hardness test The hardness of the surface of the sheet was measured with an Asker C hardness tester to be 2
It was measured at 5 ° C.

(4) Tensile Strength, Tear Strength and Elongation Test Dumbbell No. 2 type test pieces punched out from the sheet were used for measurement according to JIS K 6301.

(5) Diameter 32 mm (thickness 10 m punched out from the impact resilience test sheet
The test piece of m) was used and measured according to JIS K6301.

(6) Feeling At 25 ° C., the feel of a polyurethane foam having a thickness of 10 mm was evaluated with a touch finger. The soft feeling is indicated by S, and the hard feeling is indicated by H.

[0086]

[Table 2]

From the results shown in Table 2, the polyurethane foams obtained in the respective examples have a density of 0.1 g / cm ^3.
The storage elastic modulus obtained from the dynamic viscoelasticity at a frequency of 10 Hz and 25 ° C. is 5 to 20 MPa,
Moreover, since tan δ is 0.16 to 0.5, it is understood that the soft and good feel and low impact resilience are simultaneously provided.

On the other hand, the polyurethane foams obtained in Comparative Examples 1, 2, 4 and 5 have a high storage elastic modulus,
Soft and not feeling good. This is also clear from the hardness (Asker C) value.

The polyurethane foam obtained in Comparative Example 3 is soft and has a good feel, but does not have a low impact resilience.

In the polyurethane foams obtained in Example 1 and Comparative Example 1, the polyol, the chain extender, the catalyst, the pigment and the foam stabilizer were compounded in substantially the same proportions, but the amount of water as the foaming agent was added. The storage elastic modulus and tan δ are different depending on. Generally, water reacts with the isocyanate component to form strong hard segments. In Example 1, Comparative Example 1
Compared with, the size and number of hard segments were increased, and thus it is presumed that the hard segment has a value of tan δ under the dynamic viscoelastic condition. Further, since an increase in the amount of water added improves the foaming ratio, it is considered that the decrease in density caused a decrease in the amount of urethane foam per constant volume and a decrease in the storage elastic modulus.

[0091]

The foam of the present invention has sufficient strength,
It has the effect of simultaneously providing a soft and good feel and low impact resilience. In particular, it can be preferably used as a foam for shoe soles.

Continued front page    F-term (reference) 4J034 BA08 CA03 CA04 CA05 CA14                       CA15 CB03 CB04 CB05 CB07                       CB08 CC08 DA01 DB04 DB05                       DB07 DF14 DG02 DG03 DG04                       DG06 DG08 DG09 DG12 DQ05                       HA07 HB17 HC03 HC12 HC13                       HC17 HC22 HC46 HC52 HC61                       HC64 HC65 HC67 HC71 HC73                       KA01 KB02 KB05 KC17 KC18                       KC35 KD12 KE02 NA01 QB01                       QB14 QB15 QB19 QC01 RA03                       RA12

Claims (7)

[Claims] 1. A density of 0.1 g / cm ³ or more,
A foam having a storage elastic modulus of 5 to 20 MPa obtained from dynamic viscoelasticity at a frequency of 10 Hz and 25 ° C. and a tan δ of 0.16 to 0.5. 2. A polyurethane foam formed according to claim 1.
The foam described. 3. A polyurethane foam obtained by mixing (a) a polyol, (b) a chain extender, (c) a polyisocyanate compound, (d) a catalyst and (e) a foaming agent and reacting them. The foam according to claim 2. 4. The foam according to claim 1, which has a tensile strength of 10 kg / cm ² or more. 5. The foam according to claim 1, which has a rebound resilience of 10 to 35%. 6. A shoe sole having the foam according to claim 1. 7. A shoe having the shoe sole according to claim 6.