JP2018050767A - insole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insole that has excellent running stability and prevents shoe sore.SOLUTION: An insole is composed of a fused body of a plurality of foamed particles. The foamed particles comprise a thermoplastic elastomer as a base resin. The insole has (i) 40% or more of an impact resilience and (ii) 0.5 or more of a coefficient of static friction.SELECTED DRAWING: None

Description

  The present invention relates to an insole. More specifically, the present invention relates to an insole provided in a shoe such as a sneaker that is made of a fused body of a plurality of foamed particles and is easy to run and difficult to slip.

  In addition to the shoe body, shoes such as sneakers and business shoes usually have an insole (insole) for reducing the impact transmitted from the sole to the sole. For the insole, from the viewpoint of imparting buffering properties, a cross-linked foam of polyethylene cross-linked foam or ethylene vinyl acetate copolymer is frequently used (for example, JP-T-2003-504444: Patent Document 1).

Special table 2003-504444 gazette

  The cross-linked foam of Patent Document 1 shows good buffer properties derived from high flexibility. However, this good shock-absorbing property has caused a problem that the legs tend to be fatigued when continuously running. Furthermore, the insole of Patent Document 1 has a problem that a slip occurs between the foot and the shoe during running, resulting in shoe rubbing.

The inventors of the present invention have good running stability and are less fatigued due to misalignment if the insole is made of a fused body of a plurality of expanded particles containing a thermoplastic elastomer as a base resin. The present inventors have found that an insole that is less likely to cause shoe rubbing can be provided, and have reached the present invention.
Thus, according to the present invention, an insole comprising a fused body of a plurality of expanded particles,
The foamed particles include a thermoplastic elastomer as a base resin,
The insole is
(I) a resilience modulus of 40% or more,
(Ii) An insole having a coefficient of static friction of 0.5 or more is provided.

According to the present invention, it is possible to provide an insole that is highly repulsive, has a high coefficient of friction, is difficult to slip, has excellent running stability, and is not easily rubbed.
When the thermoplastic elastomer is selected from an ester-based elastomer and an olefin-based elastomer, it is possible to provide an insole that is more excellent in running stability and is less likely to rub on shoes.

  The insole is composed of a fused body of a plurality of expanded particles. The number of the expanded particles constituting the fusion bonded body is not particularly limited, and can be appropriately set according to the shape and size of the insole desired to be formed.

(1) Physical properties of insole (i) Rebound resilience The insole may have a rebound resilience of 40% or more. When the rebound resilience is lower than 40%, the foot is easily fatigued when continuously running. The rebound resilience may be in the range of 40-100%.
(Ii) Static friction coefficient The insole has a static friction coefficient of 0.5 or more. When the coefficient of static friction is less than 0.5, there is a shift between the foot and the foot during running, and as a result, shoe rubbing may occur. The static friction coefficient is more preferably 0.55 or more, and still more preferably 0.6 or more.
(Iii) Asker C hardness The insole preferably has an Asker C hardness of 30 to 60. By having Asker C hardness in this range, moderate impact resistance can be imparted to the insole. If the Asker C hardness is less than 30, the foot may be easily fatigued when running continuously because it is too soft. If it is greater than 60, the foot may be too hard and the foot may become tired. The Asker C hardness is preferably 35 to 55.

(Iv) Density The insole preferably has a density of 0.03 to 0.25 g / cm ³ . By having a density in this range, a lighter insole can be provided. When the density is less than 0.03 g / cm ³ , the strength is insufficient, and it may be broken by an impact during traveling. If it is greater than 0.25 g / cm ³ , the lightness may be impaired. The density is preferably 0.04 to 0.22 g / cm ³ , and more preferably 0.05 to 0.2 g / cm ³ .

(2) Base resin The foamed particles constituting the fusion-bonded body contain a thermoplastic elastomer as a base resin. By including a thermoplastic elastomer, moderate impact resistance and recoverability can be imparted to the filler.
The thermoplastic elastomer can be selected from, for example, ester elastomers and olefin elastomers. The base resin may consist only of an ester elastomer or an olefin elastomer, or may be a mixture of these elastomers.

(I) Ester Elastomer The ester elastomer is not particularly limited as long as it has a predetermined strength and hardness and gives a lightweight filler. For example, an ester elastomer containing a hard segment and a soft segment can be mentioned.
The hard segment is composed of, for example, a dicarboxylic acid component and / or a diol component.
Examples of the dicarboxylic acid component include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, and succinic acid, and derivatives thereof, and components derived from aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and derivatives thereof.
Examples of the diol component include C _2-10 alkylene glycol such as ethylene glycol, propylene glycol, and butanediol (for example, 1,4-butanediol), (poly) oxy C _2-10 alkylene glycol, and C _5-12 cycloalkanediol. Bisphenols or their alkylene oxide adducts. The hard segment may have crystallinity.
As the soft segment, a polyester type segment and / or a polyether type segment can be used.

Polyester type soft segments include dicarboxylic acids (aliphatic C _4-12 dicarboxylic acids such as adipic acid) and diols (C _2-10 alkylene glycol such as 1,4-butanediol, ethylene glycol, etc. Aliphatic polyesters such as polycondensates with (poly) oxy C _2-10 alkylene glycol), polycondensates of oxycarboxylic acids and ring-opening polymers of lactones (C _3-12 lactones such as ε-caprolactone). Can be mentioned. The polyester type soft segment may be amorphous. Specific examples of the polyester as the soft segment include polyesters of C _2-6 alkylene glycol such as caprolactone polymer, polyethylene adipate, polybutylene adipate, and C _6-12 alkanedicarboxylic acid. The number average molecular weight of this polyester may be in the range of 200 to 15000, in the range of 200 to 10000, or in the range of 300 to 8000.
Examples of the polyether type soft segment include a segment derived from an aliphatic polyether such as polyalkylene glycol (for example, polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol). The number average molecular weight of the polyether may be in the range of 200 to 10000, in the range of 200 to 6000, or in the range of 300 to 5000.
The soft segment includes a polyester having a polyether unit such as a copolymer of an aliphatic polyester and a polyether (polyether-polyester), a polyether such as a polyoxyalkylene glycol (for example, polyoxytetramethylene glycol). And a segment derived from polyester of an aliphatic dicarboxylic acid.
The mass ratio of the hard segment and the soft segment may be 20:80 to 90:10, 30:70 to 85:15, 40:60 to 80:20, 45: 55-70: 30 may be sufficient.
As the ester-based elastomer, a PELPLENE series or a VYLON series manufactured by Toyobo Co., Ltd. can be suitably used. In particular, it is preferable to use the perprene series.

(Ii) Olefin-based elastomer The olefin-based elastomer may be cross-linked or non-cross-linked. Non-crosslinked means that the foam fraction obtained from the insole has an insoluble gel fraction in xylene of 3.0% by mass or less. Crosslinking means that the gel fraction is more than 3.0% by mass.
Here, the gel fraction of the olefin elastomer is measured in the following manner.
The mass W1 of the insole is measured. The insole is then heated at reflux for 3 hours in 80 ml of boiling xylene. Next, the residue in xylene is filtered using an 80-mesh wire mesh, the residue remaining on the wire mesh is dried at 130 ° C. for 1 hour, and the mass W2 of the residue remaining on the wire mesh is measured. The gel fraction of the insole can be calculated based on the following formula.
Gel fraction (mass%) = 100 × W2 / W1
The base resin preferably contains a non-crosslinked olefinic elastomer.
The non-crosslinked olefin-based elastomer is not particularly limited as long as it can give a predetermined rebound resilience and static friction coefficient to the insole in the absence of mineral oil. Examples of the non-crosslinked olefin elastomer include those having a structure in which a hard segment and a soft segment are combined. Such a structure gives rubber elasticity at room temperature and gives the property of being plasticized and moldable at high temperature.
For example, a non-crosslinked olefin elastomer in which the hard segment is a polypropylene resin and the soft segment is a polyethylene resin can be used.

As the former polypropylene resin, a resin mainly composed of polypropylene can be used. Polypropylene may have stereoregularity selected from isotactic, syndiotactic, atactic and the like.
As the latter polyethylene-based resin, a resin mainly composed of polyethylene can be used. Examples of components other than polyethylene include polyolefins such as polypropylene and polybutene.

  The non-crosslinked olefin elastomer may contain a softening agent. Examples of the softener include petroleum oil softeners such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt and petroleum jelly, coal tar softeners such as coal tar and coal tar pitch, castor oil, rapeseed oil, large Fat oil-based softeners such as bean oil, coconut oil, waxes such as tall oil, beeswax, carnauba wax, lanolin, fatty acids such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, or metal salts thereof, naphthene Acid or metal soaps thereof, pine oil, rosin or derivatives thereof, terpene resins, petroleum resins, coumarone indene resins, synthetic polymer materials such as atactic polypropylene, ester plasticizers such as dioctyl phthalate, dioctyl adipate, dioctyl sebacate , Diisododecyl carbonate, etc. Ester plasticizers, other microcrystalline wax, sub (factice), liquid polybutadiene, modified liquid polybutadiene, liquid Thiokol, and hydrocarbon-based synthetic lubricating oils. Of these, petroleum softeners and hydrocarbon synthetic lubricants are preferred.

  Non-crosslinked olefinic elastomers are polymerization type elastomers that are produced directly in the polymerization reaction vessel by polymerizing monomers that become hard segments and monomers that become soft segments; kneading machines such as Banbury mixers and twin screw extruders And a blend type elastomer produced by physically dispersing a polypropylene resin as a hard segment and a polyethylene resin as a soft segment.

  The non-crosslinked olefin-based elastomer also has an effect that the recyclability of the manufactured insole can be improved. In addition, it is easy to produce with a foaming machine similar to the case of foaming a normal polyolefin resin. Therefore, even when the insole is recycled and supplied again to the foaming machine to perform foam molding, foaming failure due to generation of a rubber component can be suppressed.

Olefinic elastomer uncrosslinked a Fourier transform infrared spectroscopy (FT-IR) maximum peak of the maximum peak range of (A2920cm ^-1) and 1376 ± 20 cm ^-1 in the range of the obtained 2920 ± 20 cm ^-1 in the measurement ( An elastomer having an A1376 cm ⁻¹ ) absorbance ratio (A2920 cm ⁻¹ / A1376 cm ⁻¹ ) in the range of 1.20 to 10 can be preferably used. When the absorbance ratio is less than 1.20, the hardness of the insole is increased, and the flexibility may be reduced. If it is greater than 10, it will be difficult to maintain the shape during foaming, which may cause shrinkage. A more preferred absorbance ratio is 1.20-5.

Further, olefinic elastomers uncrosslinked, the maximum peak of the maximum peak range of (A2920cm ^-1) and 720 ± 20 cm ^-1 in the 2920 range of ± 20 cm ^-1 obtained in FT-IR measurements (A720cm ^-1) An elastomer having an absorbance ratio (A2920 cm ⁻¹ / A720 cm ⁻¹ ) in the range of 0.02 to 0.5 can be preferably used. When the absorbance ratio is less than 0.02, the hardness of the insole is increased, which may cause a decrease in flexibility. When it is larger than 0.5, it is difficult to maintain the shape during foaming, which may cause shrinkage. A more preferable absorbance ratio is 0.05 to 0.4.

Incidentally, the absorbance at 2920 cm ^-1 obtained from an infrared absorption spectrum A2920cm ^-1 is corresponds to the absorption spectrum from absorption spectrum derived from the C-H stretching vibration of methylene group contained in the polymethylene chain olefinic elastomer and is the absorbance A1376cm ^-1 at 1376cm ^-1 is the absorbance corresponding to the absorption spectrum derived from the CH ₃ symmetric deformation vibration of -C-CH ₃ site contained in the olefin-based elastomer means respectively ing. Therefore, by measuring this absorbance ratio, it is possible to roughly estimate the constituent components and the proportions of the hard segment and soft segment in the non-crosslinked olefin elastomer. Absorbance A 720 cm ⁻¹ at 720 cm ⁻¹ is an absorbance corresponding to an absorption spectrum derived from the skeletal vibration of the polymethylene chain in the olefin elastomer. By measuring the absorbance ratio with the maximum peak in the above range of 2920 ± 20 cm ⁻¹ , it is possible to roughly estimate the constituent components and ratios of the hard segment and soft segment in the non-crosslinked olefin elastomer.

The non-crosslinked olefin-based elastomer preferably has a Shore A hardness of 30 to 100, and more preferably 40 to 90. The Shore A hardness may be 50-100 or 60-90. The hardness of the non-crosslinked polyolefin elastomer is measured according to a durometer hardness test (JIS K6253: 97).
The non-crosslinked olefin elastomer preferably has a Shore D hardness of 10 to 70, more preferably 20 to 60. The hardness of the non-crosslinked polyolefin-based elastomer is measured according to a durometer hardness test (ASTM D2240: 95).
The non-crosslinked polyolefin-based elastomer preferably has a melting point of 80 to 180 ° C, more preferably 90 to 170 ° C. Melting | fusing point is measured based on description of JISK7121: 2012, for example.

(Iii) Other resins The base resin may contain other resins as long as the effects of the present invention are not impaired. The other resin may be a known thermoplastic resin or thermosetting resin.

(3) Manufacturing method An insole can be manufactured by heat-molding a pair of molds in which a plurality of foam particles are filled in a mold using a heating medium. For example, foam particles are filled into a mold constituted by a mold having a large number of small holes, the foam particles are heated and foamed with pressurized steam, and the voids between the foam particles are filled and the foam particles are fused to each other. Can be obtained by integrating them.
In addition to the above, the insole may be obtained by pressing a foam integrated in a plate shape with a predetermined mold.
Further, the insole may be obtained by slicing a foam integrated into a plate shape and then pressing it with a predetermined mold.
Alternatively, the insole may be obtained by cutting a plate-like foam.

  Furthermore, the foaming particles may be impregnated with an inert gas or air (hereinafter referred to as an inert gas or the like) to improve the foaming power of the foamed particles. By improving the foaming force, the fusing property between the foamed particles is improved at the time of heat foaming, and the foamed particles have a further excellent foamability. In addition, as an inert gas, a carbon dioxide, nitrogen, helium, argon etc. are mentioned, for example.

As a method of impregnating the expanded particles with an inert gas or the like, for example, a method of impregnating the expanded particles with an inert gas or the like by placing the expanded particles in an atmosphere of an inert gas or the like having a pressure equal to or higher than normal pressure. Is mentioned. The foamed particles may be impregnated with an inert gas or the like before filling into the mold, but after filling the foamed particles into the mold and placed in an atmosphere of inert gas or the like together with the mold, the foamed particles are impregnated. May be. When the inert gas is nitrogen, it is preferable to leave the expanded particles in a nitrogen atmosphere of 0.1 to 2.0 MPa for 20 minutes to 24 hours.
When the foam particles are impregnated with an inert gas, the foam particles may be heated and foamed in the mold as they are. However, before the foam particles are filled in the mold, the foam particles are heated and foamed to be highly foamed. It is also possible to form expanded particles with a magnification, fill the mold, and heat and foam. By using such expanded particles having a high expansion ratio, an insole having a high expansion ratio can be obtained.

The foam particles filled in the mold can be obtained through a step of impregnating resin particles with a foaming agent to obtain expandable particles (impregnation step) and a foaming step of foaming the expandable particles.
(I) Impregnation step (a) Resin particles The resin particles can be obtained using a known production method and production equipment.
For example, resin particles can be produced by granulating a melt-kneaded product of resin extruded from an extruder by underwater cutting, strand cutting or the like. The temperature, time, pressure, etc. at the time of melt-kneading can be appropriately set according to the raw materials used and the production equipment.
The melt kneading temperature in the extruder at the time of melt kneading is preferably 170 to 250 ° C, more preferably 200 to 230 ° C, which is a temperature at which the resin is sufficiently softened. The melt-kneading temperature means the temperature of the melt-kneaded material inside the extruder as measured at the center temperature of the melt-kneaded material flow path near the extruder head with a thermocouple thermometer.

The shape of the resin particles is, for example, a true sphere, an elliptical sphere (egg), a columnar shape, a prismatic shape, a pellet shape, or a granular shape.
The resin particles preferably have an L / D of 0.8 to 3 when the length is L and the average diameter is D. When the L / D of the resin particles is less than 0.8 or exceeds 3, the filling property into the mold may be lowered. The length L of the resin particles refers to the length in the extrusion direction, and the average diameter D refers to the diameter of the cut surface of the resin particles substantially perpendicular to the direction of the length L.
The resin particles preferably have an average particle diameter of 0.5 to 3.5 mm. When the average particle diameter is less than 0.5 mm, the holding power of the foaming agent may be reduced and foamability may be reduced. When larger than 3.5 mm, the filling property in a shaping | molding die may fall.

The resin particles may contain a bubble regulator.
Examples of the air conditioner include sodium bicarbonate citric acid, higher fatty acid amide, higher fatty acid bisamide, higher fatty acid salt, and inorganic cell nucleating agent. These bubble regulators may be used in combination.
Examples of higher fatty acid amides include stearic acid amide and 12-hydroxystearic acid amide.
Examples of higher fatty acid bisamides include ethylene bis stearamide, ethylene bis-12-hydroxy stearamide, and methylene bis stearamide.
An example of the higher fatty acid salt is calcium stearate.
Examples of inorganic cell nucleating agents include talc, calcium silicate, synthetic or naturally produced silicon dioxide, and the like.
In addition, the resin particles may contain a flame retardant such as hexabromocyclododecane and triallyl isocyanurate hexabromide, and a colorant such as carbon black, iron oxide, and graphite.

(B) Expandable particles Expandable particles are produced by impregnating resin particles with a foaming agent. As a procedure for impregnating the resin particles with the foaming agent, a known procedure can be used. For example, by supplying resin particles, a dispersing agent and water in an autoclave and stirring, the resin particles are dispersed in water to produce a dispersion, and a foaming agent is press-fitted into the dispersion. And a method of impregnating with a foaming agent.
The dispersant is not particularly limited, and examples thereof include poorly water-soluble inorganic substances such as calcium phosphate, magnesium pyrophosphate, sodium pyrophosphate, magnesium oxide, and hydroxyapatite, and surfactants such as sodium dodecylbenzenesulfonate.
As the blowing agent, general-purpose ones are used, and examples thereof include inorganic gases such as air, nitrogen and carbon dioxide (carbon dioxide); aliphatic hydrocarbons such as propane, butane and pentane; halogenated hydrocarbons, and inorganic substances. Gas is preferred. In addition, a foaming agent may be used independently and may use 2 or more types together.

  The amount of the foaming agent impregnated into the resin particles is preferably 1 to 12 parts by mass with respect to 100 parts by mass of the resin particles, although it depends on the type of foaming agent. When the content of the foaming agent is less than 1 part by mass, the foaming power becomes low, and it may be difficult to foam well at a high foaming ratio. When it exceeds 12 parts by mass, the plasticizing effect becomes too great, the viscosity at the time of foaming decreases, the bubble film tends to be broken, and shrinkage tends to occur. A more preferable amount of the blowing agent is 1 to 10 parts by mass. Within this range, the foaming power can be sufficiently increased, and even if the foaming ratio is high, foaming can be made even better.

The content (impregnation amount) of the foaming agent impregnated with respect to 100 parts by mass of the resin particles is measured as follows.
The mass Xg before putting the resin particles in the pressure vessel is measured. After impregnating the resin particles with the foaming agent in the pressure vessel, the mass Yg after taking out the impregnated material from the pressure vessel is measured. The content (impregnation amount) of the foaming agent impregnated with respect to 100 parts by mass of the resin particles is obtained by the following formula.
Foaming agent content (parts by mass) = ((Y−X) / X) × 100
If the impregnation temperature of the foaming agent into the resin particles is low, the time required for impregnating the foaming agent into the resin particles becomes long and the production efficiency may be lowered. On the other hand, when the particle size is high, the resin particles may be fused to generate a bond particle. The impregnation temperature is preferably -20 to 120 ° C, more preferably 0 to 110 ° C. A foaming aid (plasticizer) may be used in combination with the foaming agent. Examples of the foaming aid (plasticizer) include diisobutyl adipate, toluene, cyclohexane, and ethylbenzene.

The shape of the expandable particle is not particularly limited, and examples thereof include a true sphere shape, an elliptic sphere shape (egg shape), a column shape, a prism shape, a pellet shape, and a granular shape.
The expandable particles preferably have an average particle diameter of 0.5 to 3.5 mm. When the average particle diameter is less than 0.5 mm, the holding power of the foaming agent may be reduced and foamability may be reduced. When larger than 3.5 mm, the filling property in a shaping | molding die may fall. More preferably, it is 0.5 to 1.5 mm.

(Ii) Foaming Step In the foaming step, the foaming temperature and the heating medium are not particularly limited as long as foamable particles can be foamed to obtain foamed particles.
Prior to foaming, an anti-fusing agent such as polyamide powder or a surfactant or an antistatic agent may be applied to the surface of the foamable particles. Examples of the antistatic agent include polyoxyethylene alkylphenol ether and stearic acid monoglyceride.
The expanded particles have a bulk density in the range of 0.01 to 0.2 g / cm ³ . If the bulk density is less than 0.01 g / cm ³ , the resulting insole may shrink, resulting in poor appearance and reduced mechanical strength of the insole. When it is larger than 0.2 g / cm ³ , the lightness of the insole may be lowered.
The expanded particles preferably have an average cell diameter of 20 to 320 μm. When the average cell diameter is less than 20 μm, the insole may contract. When it is larger than 320 μm, the appearance of the insole may be deteriorated or the fusion may be poor. The average cell diameter is more preferably 20 to 200 μm, still more preferably 40 to 150 μm.

  The expanded particles preferably have an average particle diameter of 1.5 to 10 mm. When the average particle diameter is less than 1.5 mm, the secondary foamability during molding may be lowered. If it is larger than 10 mm, the filling property to the mold may be lowered when the insole is produced by heat foaming. The average particle diameter is more preferably 2 to 5 mm.

(4) Shape of insole The shape of the insole is not particularly limited as long as it is easy to run and the foot placed in the shoe is difficult to slip. For example, the insole may have a shape where the heel can be accommodated at a location where the insole is in contact with the heel, and the insole may have a convex portion that reinforces the arch of the arch at a location where the insole is in contact with the arch. On the surface of the insole, a skin material such as a cloth, a nonwoven fabric, or a resin film may be laminated. The skin material can be integrated with the insole with an adhesive by heat fusion.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
<Average particle diameter of expanded particles>
About 50 g of the foamed particles were sieved using a low-tap type sieve shaker (manufactured by Iida Seisakusho Co., Ltd.) 16.00 mm, 13.20 mm, 11.20 mm, 9.50 mm, 8.00 mm, 6.70 mm, 5. JIS standard sieves of 60mm, 4.75mm, 4.00mm, 3.35mm, 2.80mm, 2.50mm, 2.36mm, 2.00mm, 1.70mm, 1.40mm, 1.18mm, 1.00mm Classify for 5 minutes. The sample mass on the sieve mesh is measured, and based on the cumulative mass distribution curve obtained from the result, the particle diameter (median diameter) at which the cumulative mass is 50% is defined as the average particle diameter.

<Bulk density of expanded particles>
First, Wg was collected as a measurement sample of foamed particles, and this measurement sample was naturally dropped into a graduated cylinder, and then the apparent volume (V) cm ³ of the sample was made constant by tapping the bottom of the graduated cylinder. The volume is measured, and the bulk density of the expanded particles is calculated based on the following formula.
Bulk density (g / cm ³ ) = mass of measurement sample (W) / volume of measurement sample (V)

<Insole density>
The mass (a) and the volume (b) of the test piece cut out from the insole (after molding and dried at 40 ° C. for 20 hours or more) are measured so that each of them has three or more significant digits, The density (g / cm ³ ) of the insole is obtained from (b).

<Static friction coefficient>
The first maximum load is measured according to the method described in JIS K7125: 1999 “Plastic-Film and Sheet-Friction Coefficient Test Method”.
A test piece of 63 mm × 63 mm × 5 mm (thickness) is cut out from the insole. The test piece and the mating material are conditioned in JIS K7100: 1999 symbol 23/50, second grade environment for 16 hours and then measured in the same environment. The sliding material is a coated steel plate (manufactured by Nisshin Steel Co., Ltd., trade name: Tsukisei GL color SELiOS / GL enamel clean / stroke ream, thickness: 0.27 mm).
Next, the test piece was affixed to a 200 g slide piece with double-sided tape, the test speed was set to 500 mm / min, the test distance was 80 mm on the sliding mating material, a spring was not used, and a Tensilon universal tester (Orientec Co., UCT-10T) was used. ) To measure the first maximum load. In this test, universal tester data processing (manufactured by UTPS-237S Soft Brain) is used for data processing. The test piece surface (63 mm × 63 mm) in contact with the material to be slid is provided with a skin. The number of tests is 5.
The static friction coefficient is calculated using the following formula.
Coefficient of static friction = first maximum load (N) / normal force 1.96 (N)

<Asker C hardness>
Asker C hardness is measured in accordance with the test method of JIS K 7312: 1996. Specifically, a sample adjusted to 50 mm × 50 mm × thickness 5 mm is pressed perpendicularly with the Asker rubber hardness meter C type in the vicinity of the fused part of the expanded particles, and the numerical value after 1 second is measured. At that time, the measurement position is measured 5 mm or more inside from the outer edge of the sample, the measurement points are secured at an interval of 5 mm, and five points are measured for one sample, and the average value is defined as Asker C hardness.

<Rebound resilience>
Measured according to JIS K 6400-3: 2011. 50 mm × 50 mm × thickness cut out from the same insole which was conditioned for 72 hours or more in an environment of temperature 23 ± 2 ° C. and humidity 50 ± 5% in a rebound resilience tester (manufactured by Kobunshi Keiki Co., Ltd., FR-2) Eight 5 mm test pieces are stacked and set, and a copper ball (φ5 / 8 inch, 16.3 g) is dropped freely from a height (a) of 500 mm, and the height (b) at the time of reaching the maximum rebound is read. The rebound resilience (%) is calculated by the formula (b) / (a) × 100. However, the measurement is performed three times using the same test piece, and the median of these values is taken as the resilience modulus.

Example 1
(1) Resin particles 100 parts by mass of TPO R110E (manufactured by Prime Polymer Co., Ltd.) which is a thermoplastic olefin elastomer, and a baking soda citrate chemical foaming agent (trade name “Finecell Master PO410K”, Dainichi 0.5 parts by mass) was continuously supplied at a pace of 45 kg / h to a tandem extruder in which a single-screw extruder having a diameter of 50 mm and a single-screw extruder having a diameter of 65 mm were connected.
The olefin elastomer was melt-kneaded so that the maximum temperature reached in the extruder was 260 ° C. The molten olefin-based elastomer was cooled so as to have a resin temperature of 230 ° C. at the front end of the extruder while passing through a downstream extruder (extruder having a diameter of 65 mm).
About from the die hole (32 nozzles with a diameter of 0.8 mm and a land length of 3.0 mm) of a die (temperature 320 ° C., inlet side resin pressure 18 MPa) equipped with the above molten olefin elastomer at the tip of the extruder It extruded into the chamber which accommodated the 70 degreeC cooling water. The extrudate was rotated at a rotational speed of 3400 rpm on a rotary blade having 8 cutting blades, cut into granules, and cooled with cooling water to obtain resin particles.

(2) Expandable particles Resin particles (average particle diameter: 1.2 mm) were sealed in a pressure vessel having a capacity of 5 L, and carbon dioxide gas was injected to an impregnation pressure of 4.0 MPa. Then, it left still for 24 hours in the temperature of 20 degreeC environment, and the expandable particle | grains were obtained by impregnating a carbon dioxide gas to a resin particle. By this method, the amount of carbon dioxide gas impregnated in the resin particles was 3.8% by mass.
(3) Foamed particles After the pressure removal in the impregnation step, the foamable particles were immediately taken out from the pressure vessel, and 0.1 parts by mass of calcium carbonate was added and mixed. Thereafter, the expandable particles were put into a cylindrical batch type pressure prefoaming machine having a volume of 50 liters and heated at a foaming temperature of 105 to 110 ° C. for 15 seconds with stirring to obtain expanded particles. The obtained expanded particles were washed with an aqueous hydrogen chloride solution to remove calcium carbonate, and then dried.
The obtained expanded particles contracted. The contracted foamed particles were sealed in a pressure vessel, and nitrogen gas was injected until the pressure gauge showed 0.5 MPa. The pressure vessel was allowed to stand at room temperature for 24 hours, and the expanded particles were impregnated with nitrogen gas. When the bulk density of the obtained expanded particles was measured, it was 0.09 g / cm ³ .

(4) Insole The foamed particles were sealed in a pressure vessel, and nitrogen gas was injected until the pressure gauge showed 1.0 MPa. The pressure vessel was allowed to stand at room temperature for 24 hours, and the expanded particles were impregnated with nitrogen gas. The foamed particles impregnated with nitrogen gas are filled into a 5 mm × 300 mm × 400 mm molding die, heated for 34 seconds with 0.10 MPa of water vapor, and cooled until the surface pressure of the foamed molded product becomes 0.01 MPa or less. As a result, a plate-like molded body was obtained. Furthermore, the insole was obtained by cutting into an insole shape. The density of the obtained insole was 0.1 g / cm ³ .

Example 2
(1) Resin particles Ester elastomer (polybutylene terephthalate (PBT) as a hard segment and aliphatic polyether as a soft segment (trade name: "Perprene GP475", melting point: 155 ° C, Vicat softening point: 110 ° C, Toyobo) 100 parts by mass) and 0.3 part by mass of an organic bubble regulator (trade name: “Kao Wax EBFF”, manufactured by Kao Corporation) were supplied to a single screw extruder and melt-kneaded at 180 to 280 ° C. Next, after the molten ester-based elastomer is cooled to adjust the viscosity, the resin is supplied from each nozzle of a multi-nozzle mold (having 8 holes of 1.3 mm in diameter) attached to the front end of the single screw extruder. Extruded and cut underwater. The water temperature was 30-50 ° C., the number of cutter blades was 8, and the cutter rotation speed was 3000-4500 rpm. The obtained resin particles had a length L of 1.4 to 1.8 mm and an average diameter D of 1.4 to 1.8 mm.
(2) Expandable particles In an autoclave with a stirrer having an internal volume of 5 L, 1.5 kg (100 parts by mass) of ester-based elastomer resin particles, 3 L of distilled water, a surfactant (trade name: “Newrex R”, Yuka Sangyo 5 g) was added and sealed, and then 16 parts by mass of blowing agent butane (normal butane: isobutane = 7: 3) was injected under stirring. The autoclave was then heated at 100 ° C. for 2 hours and cooled to 25 ° C. After completion of cooling, the autoclave was depressurized and dehydrated to obtain expandable particles.

(3) Expanded particles After applying 0.25 parts by mass of an anti-fusing agent (trade name: “Epan 450”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to 1.5 kg (100 parts by mass) of expandable particles, the internal volume is 50 L. Were added to a cylindrical pre-foaming machine with a stirrer and heated with water vapor with a gauge pressure of 0.14 MPa while stirring to obtain expanded particles. The bulk density of the expanded particles was 0.180 g / cm ³ .
(4) Insole An insole was obtained in the same manner as in Example 1 except that the nitrogen gas impregnation pressure was set to 0.5 MPa, and the pressure of the steam introduced during molding was set to a gauge pressure of 0.21 MPa.

Example 3
(1) Resin Particles Prepared by the same method as in Example 1.
(2) Expandable particle It produced by the method similar to Example 1. FIG. The amount of impregnated gas of the expandable particles was 11.8% by mass.
(3) Expanded particles The foamed particles were produced in the same manner as in Example 1 except that the gauge pressure of water vapor was changed to 0.15 MPa. The bulk density of the expanded particles was 0.131 g / cm ³ .
(4) Insole An insole was produced in the same manner as in Example 1 except that the gauge pressure of water vapor was changed to 0.20 MPa.
Table 1 summarizes the physical properties of the insole.

  From Table 1, it can be seen that an insole that is excellent in running stability and hardly rubs on shoes can be obtained by forming the insole from a fused body of expanded particles containing a thermoplastic elastomer as a base resin.

Claims (2)

An insole comprising a fused body of a plurality of expanded particles,
The foamed particles include a thermoplastic elastomer as a base resin,
The insole is
(I) a resilience modulus of 40% or more,
(Ii) An insole having a coefficient of static friction of 0.5 or more. The insole according to claim 1, wherein the thermoplastic elastomer is selected from an ester elastomer and an olefin elastomer.