JP7051654B2 - Wax-containing foam particles, foam moldings and methods for producing them - Google Patents

Description

The present invention relates to wax-containing foamed particles, foamed molded products, and methods for producing them. More specifically, the present invention relates to wax-containing foamed particles that can give a foamed molded product with improved meltability, a foamed molded product with improved meltability, and a method for producing them.

Conventionally, as a cushioning material or a packing material, a foamed molded product in which a plurality of foamed particles made of polystyrene, polypropylene or the like are fused is widely used. The foamed molded product obtained by fusing a plurality of foamed particles has an advantage that a complicated shape can be formed as compared with the foamed molded product obtained by extrusion foaming. A foam molded product made of polystyrene, polypropylene, or the like has a problem that it is difficult to use it in applications that require high impact resilience. Therefore, there has been a demand for a foam molded product capable of achieving high impact resilience.

In response to the above request, Japanese Patent Application Laid-Open No. 2016-190989 (Patent Document 1) proposes a foamed molded product using amide-based elastomer foamed particles.

Japanese Unexamined Patent Publication No. 2016-190989

The inventors of the present invention have found that foamed particles can be produced not only with an amide-based elastomer but also with an ester-based elastomer having excellent impact resilience. Here, the foamed molded product made of a fused body of a plurality of foamed particles is required to have high fusion property between the foamed particles. Therefore, it was investigated to improve the fusion property even in the foamed molded product obtained from the foamed particles using the ester-based elastomer as the base resin.

The inventors of the present invention have described that the ester-based elastomer foam particles are composed of a resin composition containing an ester-based elastomer as a base resin and a specific amount of wax as a fusion improver. We have found that it is possible to provide a foamed molded product having improved properties, and have arrived at the present invention.
Thus, according to the present invention, it is composed of a resin composition containing an ester-based elastomer as a base resin and a wax as a fusion improver, and the wax is a higher fatty acid amide having 12 to 22 carbon atoms and a carbon number of carbon atoms. Wax-containing foam selected from 25 to 46 higher fatty acid bisamides and 12 to 22 carbon atoms and containing 0.01 to 5 parts by mass with respect to 100 parts by mass of the ester-based elastomer. Particles are provided.
Further, according to the present invention, it is a method for producing the wax-containing foamed particles.
A method for producing wax-containing foamed particles, which comprises a step of impregnating resin particles containing the ester-based elastomer and the wax with a foaming agent to obtain foamable particles, and a step of foaming the foamable particles. Is provided.
Further, according to the present invention, there is provided a foamed molded product obtained by in-mold foaming of the wax-containing foamed particles.
Further, according to the present invention, it is a method for producing the above-mentioned foam molded product.
Provided is a method for producing a foamed molded product, which comprises a step of in-mold foaming the wax-containing foamed particles using steam having a gauge pressure of 0.05 to 0.4 MPa as a heating medium.

The wax-containing foamed particles of the present invention can provide a foamed molded product having improved fusion property.

Further, in any of the following cases, it is possible to provide wax-containing foamed particles capable of producing a foamed molded product having further improved fusion properties.
(1) The wax is selected from higher fatty acid amides, higher fatty acid bisamides and higher fatty acid salts.
(2) The wax is selected from a higher fatty acid amide having 12 to 22 carbon atoms, a higher fatty acid bisamide having 25 to 46 carbon atoms, and a higher fatty acid salt having 12 to 22 carbon atoms.
(3) The resin composition is
(I) Shore D hardness of 0 to 65 (ii) Melting point of 100 to 200 ° C. (iii) Storage elastic modulus measured by melt viscoelasticity at crystallization temperature Tc is in the range of 1 × 10 ⁶ to 2 × 10 ⁷ Pa (iv). ) The storage elastic modulus measured by solid viscoelasticity at the Vicat softening temperature Tv-10 ° C. has at least one of the physical properties in the range of 1 × 10 ⁷ to 2 × 10 ⁸ Pa.
(4) Wax-containing foamed particles
(I) Bulk density of 0.02 to 0.4 g / cm ³ (ii) Average bubble diameter of 10 to 300 μm (iii) Closed cell ratio of 60 to 100% (iv) Average particle diameter of 1.5 to 15 mm Has at least one of the physical characteristics.

It is a cross-sectional photograph of the foamed particles of Example 1. It is a cross-sectional photograph of the foamed particles of Example 2. It is a cross-sectional photograph of the foamed particles of Example 3. It is a cross-sectional photograph of the foamed particles of Example 4. It is a cross-sectional photograph of the foamed particles of Example 5. It is a cross-sectional photograph of the foamed particles of Example 6. It is a cross-sectional photograph of the foamed particles of Example 7. It is a cross-sectional photograph of the foamed particles of Example 8. It is a cross-sectional photograph of the foamed particles of Comparative Example 1. It is a cross-sectional photograph of the foamed particles of Comparative Example 2. It is a cross-sectional photograph of the foamed particles of Comparative Example 3.

(Wax-containing foam particles)
The wax-containing foamed particles of the present invention (hereinafter, simply foamed particles) are composed of a resin composition containing an ester-based elastomer as a base resin and wax as a fusion improver.
(1) Ester-based elastomer The ester-based elastomer is not particularly limited as long as it is provided with a foamed molded product. For example, an ester-based 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. It may be composed of two components, a dicarboxylic acid component and a dicarboxylic acid component and a diol component.
Examples of the dicarboxylic acid component include aliphatic dicarboxylic acids such as oxalic acid, malonic acid and succinic acid and their derivatives, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid and their derivatives.
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 alkylene oxide adducts thereof and the like. The hard segment may have crystallinity.

As the soft segment, a polyester type 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 glycols such as 1,4-butanediol, ethylene glycols). (Poly) Poly-polyesters such as polycondensates with _{oxyC 2-10} alkylene glycol), polycondensates with 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 a soft segment include polyesters of C _2-6 alkylene glycols such as caprolactone polymer, polyethylene adipate and polybutylene adipate and C _6-12 alkandicarboxylic acid. The number average molecular weight of this polyester may be in the range of 200 to 15,000, may be in the range of 200 to 10000, or may be in the range of 300 to 8000.
Examples of the polyether type soft segment include segments derived from aliphatic polyethers 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, may be in the range of 200 to 6000, or may be in the range of 300 to 5000.

The soft segment is a polyester having a polyether unit such as a copolymer of an aliphatic polyester and a polyether (polyester-polyester), a polyether such as polyoxyalkylene glycol (eg, polyoxytetramethylene glycol). It may be a segment derived from polyester with an aliphatic dicarboxylic acid.
The mass ratio between the hard segment and the soft segment may be 20:80 to 90:10, 30:70 to 90:10, or 30:70 to 80:20. It may be 40:60 to 80:20 or 40:60 to 75:25.
When the dicarboxylic acid component is a terephthalic acid component and other dicarboxylic acid components, the ester-based elastomer contains a hard segment in a proportion of 30 to 80% by mass and contains 5 dicarboxylic acid components other than the terephthalic acid component. It may be contained in a proportion of up to 30% by mass. The ratio of the dicarboxylic acid component other than the terephthalic acid component may be 5 to 25% by mass, 5 to 20% by mass, or 10 to 20% by mass. The proportion of the dicarboxylic acid component can be obtained by quantitatively evaluating the NMR spectrum of the resin.
It is preferable that the dicarboxylic acid component other than the terephthalic acid component is an isophthalic acid component. By containing the isophthalic acid component, the crystallinity of the elastomer tends to decrease, the foam moldability is improved, and a foam molded product having a lower density can be obtained.

The resin composition is
(I) Shore D hardness of 0 to 65 (ii) Melting point of 100 to 200 ° C. (iii) Storage elastic modulus measured by melt viscoelasticity at crystallization temperature Tc is in the range of 1 × 10 ⁶ to 2 × 10 ⁷ Pa (iv). ) It is preferable that the storage elastic modulus by solid viscoelasticity measurement at the Vicat softening temperature Tv-10 ° C. has at least one of the physical properties in the range of 1 × 10 ⁷ to 2 × 10 ⁸ Pa.
If the shore D hardness is greater than 65, softening during foaming becomes difficult, and a low-density foamed molded product may not be obtained. The shore D hardness may be in the range of 20 to 60, in the range of 25 to 60, or in the range of 30 to 60.
If the melting point is less than 100 ° C., shrinkage may occur after the prefoaming step, making molding difficult. If the temperature is higher than 200 ° C., softening during foaming becomes difficult, and a low-density foamed molded product may not be obtained. The melting point may be in the range of 120 to 200 ° C. or may be in the range of 120 to 190 ° C.
If the storage elastic modulus (molten viscoelasticity) is less than 1 × 10 ⁶ Pa, the foamed shape may not be maintained and shrinkage may occur during the cooling process after foaming. If it is larger than 2 × 10 ⁷ Pa, softening during foaming becomes difficult, and a desired foaming multiple (density) may not be obtained. The storage elastic modulus (molten viscoelasticity) may be in the range of 1 × 10 ⁶ to 1.5 × 10 ⁷ Pa, or may be in the range of 1 × 10 ⁶ to 1 × 10 ⁷ Pa, 3 ×. It may be in the range of 10 ⁶ to 1 × 10 ⁷ Pa.
If the storage elastic modulus (solid viscoelasticity) is less than 1 × ¹⁰⁷ , the foamed shape cannot be maintained and shrinks during the cooling process after foaming. If it is larger than 2 × 10 ⁸ Pa, softening during foaming becomes difficult, and a desired foaming multiple (density) may not be obtained. The storage elastic modulus (solid viscoelasticity) may be in the range of 1 × 10 ⁷ to 1.5 × 10 ⁸ Pa, or may be in the range of 1 × 10 ⁷ to 1 × 10 ⁸ Pa, and may be in the range of 1 × 10 7 to 1 × 10 8 Pa. It may be in the range of 10 ⁷ to 8 × 10 ⁷ Pa.

(2) Substrate Resin The base resin may contain other resins in addition to the ester-based elastomer as long as the effects of the present invention are not impaired. The other resin may be a known thermoplastic resin or thermosetting resin.
The base resin may also contain a flame retardant, a colorant, an antistatic agent, a spreading agent, a plasticizer, a flame retardant aid, a cross-linking agent, a filler, a lubricant and the like.
Examples of the flame retardant include hexabromocyclododecane, triallyl isocyanurate 6 bromide and the like.
Examples of the colorant include inorganic pigments such as carbon black, graphite and titanium oxide, organic pigments such as phthalocyanine blue, phthalocyanine green, quinacridone red and isoindolenone yellow, and special pigments such as metal powder and pearl.
Examples of the antistatic agent include polyoxyethylene alkylphenol ether, stearic acid monoglyceride and the like.
Examples of the spreading agent include polybutene, polyethylene glycol, silicone oil and the like.

(3) Wax Wax is not particularly limited as long as it is possible to improve the fusion of the foamed particles to each other. The wax can be selected from, for example, higher fatty acid amides, higher fatty acid bisamides and higher fatty acid salts. More specifically, the higher fatty acid amides are lauric acid amides, tridecyl acid amides, myristic acid amides, pentadecyl acid amides, palmitic acid amides, margaric acid amides, stearic acid amides, nonadesilic acid amides, arachidic acid amides, and henicosyl acid amides. , Bechenic acid amide, 12-hydroxystearic acid amide, oleic acid amide and erucic acid amide (higher fatty acid amide having 12 to 22 carbon atoms), higher fatty acid bisamides are methylene bisstearic acid amides, ethylene bislauric acid amides, ethylene. From bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide (higher fatty acid bisamide having 25 to 46 carbon atoms), higher fatty acid salts are magnesium laurate, calcium laurate, zinc laurate, magnesium stearate, steer. It can be selected from calcium phosphate and zinc stearate (higher fatty acid salts having 12 to 22 carbon atoms).
The wax is contained in an amount of 0.01 to 5 parts by mass with respect to 100 parts by mass of the ester-based elastomer. If the wax content is less than 0.01 parts by mass, sufficient fusion between the foamed particles may not be obtained. If it is more than 5 parts by mass, the physical properties of the resin may change, and for example, the strength and the elastic modulus of the foam may decrease.

(4) Physical characteristics of foamed particles Foamed particles are
(I) Bulk density of 0.02 to 0.4 g / cm ³ (ii) Average bubble diameter of 10 to 300 μm (iii) 60 to 100% closed cell ratio (iv) Average particle diameter of 1.5 to 15 mm It is preferable to have at least one of the physical properties.
If the bulk density is less than 0.02 g / cm ³ , it may shrink to cause poor appearance or decrease in strength. If it is larger than 0.4 g / cm ³ , it may not be possible to obtain a lightweight foam molded product. The bulk density may be in the range of 0.04 to 0.4 g / cm ³ , may be in the range of 0.06 to 0.4 g / cm ³ , and may be in the range of 0.06 to 0.3 g / cm ³ . It may be in the range of.
If the average bubble diameter is less than 10 μm, it may shrink and cause poor appearance. If it is larger than 300 μm, the fusion of the foamed particles may be poor during molding and the strength may be lowered. The average bubble diameter may be in the range of 10 to 250 μm or may be in the range of 10 to 200 μm.
When the closed cell ratio is less than 60%, it becomes difficult to apply the internal pressure, and the moldability may be deteriorated. The closed cell ratio may be in the range of 65 to 100% or 70 to 100%.
If the average particle size is less than 1.5 mm, it may be difficult to produce the foamed particles and the production cost may increase. If it is larger than 15 mm, the filling property into the mold may decrease when the foamed molded product is produced by in-mold molding. The average particle size may be in the range of 1.5 to 12 mm or may be in the range of 1.5 to 9 mm.

(Manufacturing method of wax-containing foamed particles)
The wax-containing foamed particles can be produced by a method including a step of impregnating resin particles containing an ester-based elastomer and wax with a foaming agent to obtain foamable particles, and a step of foaming the foamable particles.

(1) Effervescent particles Effervescent particles can be obtained through a step (impregnation step) of impregnating resin particles with a foaming agent to obtain effervescent particles.
The foaming agent may be an organic gas or an inorganic gas. Examples of the inorganic gas include air, nitrogen and carbon dioxide (carbonic acid gas). Examples of the organic gas include hydrocarbons such as propane, butane and pentane, and fluorine-based foaming agents. Only one kind of the above foaming agent may be used, or two or more kinds may be used in combination.
The amount of the foaming agent contained in the base resin may be 1 to 12 parts by mass with respect to 100 parts by mass of the base resin. If it is less than 1 part by mass, the foaming power becomes low, and it is difficult to increase the foaming multiple. If the content of the foaming agent exceeds 12 parts by mass, the plasticizing effect becomes large, shrinkage occurs during foaming, and good foamed particles may not be obtained. The amount of the foaming agent may be 5 to 12 parts by mass. Within this range, the foaming power can be sufficiently increased, and foaming can be performed even better.
As a method of impregnating the resin particles with a foaming agent, a known method can be used. For example, resin particles, a dispersant, and water are supplied into an autoclave and stirred to disperse the resin particles in water to produce a dispersion liquid, and a foaming agent is press-fitted into the dispersion liquid to be contained in the resin particles. Is impregnated 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, and magnesium oxide, and surfactants such as sodium dodecylbenzene sulfonate.

If the impregnation temperature of the foaming agent into the resin particles is low, the time required for impregnating the resin particles with the foaming agent becomes long, and the production efficiency may decrease. If it is high, the resin particles may be fused to each other to generate bonded particles. The impregnation temperature may be −20 to 120 ° C., 0 to 120 ° C., 20 to 120 ° C., or 40 to 120 ° C. A foaming aid (plasticizer) or a bubble adjusting agent may be used in combination with the foaming agent.
Examples of the effervescence aid (plasticizer) include diisobutyl adipate, toluene, cyclohexane, ethylbenzene and the like.

Examples of the bubble adjusting agent include higher fatty acid amides, higher fatty acid bisamides, higher fatty acid salts, and inorganic bubble nucleating agents. A plurality of types of these bubble adjusting agents may be combined.
Examples of the higher fatty acid amide include stearic acid amide and 12-hydroxystearic acid amide.
Examples of the higher fatty acid bisamide include ethylene bisstearic acid amide and methylene bisstearic acid amide.
Examples of the higher fatty acid salt include calcium stearate.
Examples of the inorganic bubble nucleating agent include talc, calcium silicate, synthetically or naturally produced silicon dioxide, and the like.
In addition to the above, a bubble adjusting agent that also serves as a chemical foaming agent may be used. Examples of such a bubble adjusting agent include citric acid sodium bicarbonate, sodium hydrogencarbonate, azodicarbonamide, dinitrosopentamethylenetetramine, benzenesulfonylhydrazide, hydrazodicarbonamide and the like.
The content of the bubble adjusting agent may be 0.005 to 2 parts by mass or 0.01 to 1.5 parts by mass with respect to 100 parts by mass of the effervescent particles. If the amount of bubble adjusting agent is less than 0.005 part by mass, it may be difficult to control the bubble diameter. When the amount of the bubble adjusting agent is more than 2 parts by mass, the physical characteristics of the resin may change, and for example, the strength of the molded product may decrease.

(2) Resin particles The shape of the resin particles is not particularly limited, and examples thereof include a true spherical shape, an elliptical spherical shape (egg shape), a columnar shape, a prismatic shape, a pellet shape, and a granular shape.
As the resin particles, the raw material pellets may be used as they are, or may be repelled to any size and shape.
The resin particles may have a length of 0.5 to 5 mm and an average diameter of 0.5 to 5 mm. When the length is less than 0.5 mm and the average diameter is less than 0.5 mm, it may be difficult to foam because the gas retention of the effervescent particles is low. When the length is larger than 5 mm and the average diameter is larger than 5 mm, heat is not transferred to the inside when foamed, so that the foamed particles may have a core. Here, the length L and the average diameter D of the resin particles are measured as follows using a caliper. The length of the resin particles in the extrusion direction at the time of repelling is defined as the length L, and the average value of the minimum diameter (minimum diameter) and the maximum diameter (maximum diameter) of the resin particles in the direction orthogonal to the extrusion direction is defined as the average diameter D.

(3) Effervescent Particles Effervescent particles can be obtained through a step of foaming the effervescent particles (foaming step).
The shape of the foamed particles is not particularly limited, and examples thereof include a true spherical shape, an elliptical spherical shape (egg shape), a columnar shape, a prismatic shape, a pellet shape, and a granular shape.
In the foaming step, the foaming temperature and the heating medium are not particularly limited as long as the foamable particles can be foamed to obtain the foamed particles.

In the foaming step, an anti-coupling agent may be added to the effervescent particles. The amount of the anti-adhesion agent added may be in the range of 0.03 to 0.3 parts by mass or in the range of 0.05 to 0.25 parts by mass with respect to 100 parts by mass of the foamable particles. If the amount of the anti-adhesion agent is less than 0.03 parts by mass, the anti-adhesion effect may not be sufficiently obtained. If the amount of the anti-bonding agent is more than 0.3 parts by mass, the strength of the foamed molded product may be lowered or the cleaning cost may be increased.
Before foaming, powdered metal soaps such as zinc stearate, calcium carbonate and aluminum hydroxide may be applied to the surface of the foamable particles. By this coating, the bond between the effervescent particles in the effervescent step can be reduced. Further, a surface treatment agent such as an antistatic agent or a spreading agent may be applied.

(Effervescent molded product)
(1) Various physical properties The foamed molded product may have a density of 0.02 to 0.4 g / cm ³ . If the density is greater than 0.4 g / cm ³ , the lightness of the foam may be reduced. If the density is less than 0.02 g / cm ³ , the foamed molded product may shrink, resulting in poor appearance or reduced strength. The density may be in the range of 0.04 to 0.4 g / cm ³ , may be in the range of 0.06 to 0.4 g / cm ³ , and may be in the range of 0.06 to 0.3 g / cm ³ . It may be a range.
The foam molded product may have a rebound resilience of 50 to 100%. If the rebound resilience is lower than 50%, it becomes difficult to use it in applications where rebound resilience is required.
The foam molded article may have a compression set of 0-15%. If the compression set is greater than 15%, it will be difficult to use in an environment where compressive stress is applied. The compression set may be in the range of 0 to 13% or in the range of 0 to 11%.
The foam molded article may have an Asker C hardness of 20-65. If the Asker C hardness is less than 20, the shape stability of the foamed molded product may decrease. If it is larger than 65, for example, sufficient impact resilience and flexibility may not be obtained. The Asker C hardness may be in the range of 20 to 60 or may be in the range of 20 to 55.
The foam molded product can have a fusion rate of 10 to 100%. If the fusion rate is less than 10%, it may not be possible to impart sufficient strength to the foamed molded product. When the fusion rate is 10 to 100%, sufficient strength can be imparted to the foamed molded product. The fusion rate may be 20 to 100%, 30 to 100%, 40 to 100%, or 50 to 100%.
The foam molded product can be used, for example, for building materials, shoe members, sporting goods, cushioning materials, seat cushions, automobile members, and the like. Specifically, the midsole, insole, and outsole members of shoes, the core material of hitting tools for sports equipment such as rackets and bats, the protective equipment for sports equipment such as pads and protectors, and medical and nursing care such as pads and protectors.・ Welfare / healthcare products, tire cores for bicycles and wheelchairs, interior materials for transportation equipment such as automobiles, seat cores, shock absorbers, vibration absorbers, shock absorbers such as fenders and floats, toys, etc. It can be used for floor base materials, wall materials, railway vehicles, airplanes, beds, cushions, etc.
The foam molded product can take an appropriate shape according to the above application.

(2) Production Method The method for producing an effervescent molded product includes a step of in-mold foaming of foamed particles using steam having a gauge pressure of 0.05 to 0.4 MPa as a heating medium. For example, the foamed particles are filled in a closed mold having a large number of small pores, the foamed particles are heated and foamed with steam to fill the voids between the foamed particles, and the foamed particles are fused and integrated with each other. Can be obtained by At that time, for example, the density of the foamed molded product can be adjusted by adjusting the filling amount of the foamed particles in the mold. When the gauge pressure of water vapor is less than 0.05 MPa, it may be difficult to foam the foamed particles in the mold, the fusion between the foamed particles may be reduced, and sufficient strength may not be imparted to the foamed molded product. If it is higher than 0.4 MPa, the foamed molded product may shrink and a foamed molded product having a good appearance may not be obtained. The gauge pressure of water vapor may be 0.05 to 0.35 MPa, 0.05 to 0.3 MPa, or 0.1 to 0.3 MPa.
Further, the foamed 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 (internal pressure applying step). By improving the foaming power, the fusion property between the foamed particles is improved at the time of foaming in the mold, and the foamed molded product has further excellent mechanical strength. Examples of the inert gas include carbon dioxide, nitrogen, helium, argon and the like.
As a method of impregnating the foamed particles with an inert gas or the like, for example, a method of impregnating the foamed particles with the inert gas or the like by placing the foamed particles in an atmosphere such as an inert gas having a pressure higher than normal pressure is used. Can be mentioned. The foamed particles may be impregnated with an inert gas or the like before being filled in the mold, but are impregnated by placing the foamed particles in an atmosphere such as an inert gas together with the mold after being filled in the mold. May be good. When the inert gas is nitrogen, the foamed particles may be left for 20 minutes to 24 hours in a nitrogen atmosphere having a gauge pressure of 0.1 to 2 MPa.

When the foamed particles are impregnated with an inert gas or the like, the foamed particles may be heated and foamed in the mold as they are, but the foamed particles are heated and foamed before being filled in the mold to be low. The particles may be made into bulky foamed particles, filled in a mold, heated, and foamed. By using such low bulk density foam particles, a low density foam molded product can be obtained.
Further, when the anti-coupling agent is used in the production of the foamed particles, the anti-coupling agent may be adhered to the foamed particles during the production of the foamed molded product. Further, in order to promote the fusion of the foamed particles to each other, the anti-coupling agent may be washed and removed before the molding step.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
<Shore D hardness of resin particles>
The resin particles dried at 100 ° C. for 3 hours were hot-pressed at a temperature of melting point Tm + 30 ° C. to prepare a smooth film having a thickness of 3 mm or more. This was measured using a "Teklock Durometer Type D" hardness tester manufactured by Teclock Co., Ltd. after adjusting the state for 24 hours or more in an environment of a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5%. The pressure surface was brought into close contact with the test piece so that the needle was perpendicular to the measurement surface of the test piece, and the scale was immediately read. Five points of the sample were measured, and the average value of these was taken as the shore D hardness.

<Melting point Tm of resin particles, crystallization temperature Tc and heat of crystallization>
The melting point and crystallization temperature were measured by the methods described in JIS K7121: 1987, JIS K7121: 2012 “Method for measuring transition temperature of plastics”. However, the sampling method and temperature conditions were as follows. After filling the bottom of the aluminum measuring container with 5 to 7 mg of the sample so that there was no gap, the aluminum lid was put on. Next, using a differential scanning calorimeter manufactured by Hitachi High-Tech Science Co., Ltd. "DSC7000X, AS-3" or SII Nanotechnology Co., Ltd. "DSC6220", the temperature was lowered from 30 ° C. to -70 ° C. under a nitrogen gas flow rate of 20 mL / min. Hold for 10 minutes and raise the temperature from -70 ° C to 220 ° C (first temperature rise), hold for 10 minutes and then lower the temperature from 220 ° C to -70 ° C (cool), hold for 10 minutes and then raise the temperature from -70 ° C to 220 ° C. The DSC curve at the time of (the second temperature rise) was obtained. All temperature raising and lowering were performed at a rate of 10 ° C./min, and alumina was used as a reference material. In the present invention, the melting temperature (melting point) is a value obtained by reading the temperature at the top of the largest melting peak observed in the second temperature raising process using the analysis software attached to the apparatus.
Further, the crystallization temperature was set as the value obtained by reading the temperature of the top of the crystallization peak on the highest temperature side observed in the cooling process using the analysis software attached to the apparatus.
The amount of heat of crystallization was measured by the method described in JIS K7122: 1987, JIS K7122: 2012 “Method for measuring transition heat of plastic”. For the amount of heat of crystallization of the crystallization peak on the highest temperature side in the cooling process, the point where the DSC curve deviates from the baseline on the high temperature side and the point where the DSC curve returns to the baseline on the low temperature side again using the analysis software attached to the device. It was calculated from the area of the part surrounded by the straight line connecting the DSC curve and the DSC curve.

<Vicut softening temperature Tv of resin particles>
The measurement was performed in accordance with the method A of JIS K7206: 2016 "Plastic-thermoplastic plastic-how to determine the bicut softening temperature (VST)". The resin particles dried at 100 ° C. for 3 hours were hot-pressed at a melting point of Tm + 30 ° C. to prepare a test piece having a thickness of 10 mm × 10 mm × thickness 5 mm. Using a "HAD-6 type" heat distortion tester manufactured by Yasuda Seiki Seisakusho Co., Ltd., measurements were performed three times under the conditions of a temperature rise rate of 50 ° C./hour and a test load of 10 N, and the average value of these was taken as the Vicat softening temperature.

<Restoration elastic modulus of resin particles (solid viscoelasticity)>
The resin dried at 90 to 100 ° C. for 3 hours was prepared into a strip-shaped sample having a length of 120 mm, a width of 10 mm, and a thickness of 0.7 to 10 mm under the conditions of a temperature of 190 to 200 ° C. using a hot press machine. As the solid viscoelasticity measuring device, an "EXSTAR DMS6100" viscoelasticity spectrometer manufactured by SII Nanotechnology Co., Ltd. was used. The sample is sampled to a length of 40 to 50 mm, and in a tension control mode, the frequency is 1 Hz, the temperature rise rate is 5 ° C./min, the measurement start temperature is 30 ° C. to the measurement end temperature of 220 ° C., the chuck interval is 20 mm, and the strain amplitude is 5 μm. The measurement was performed under the conditions of minimum tension / compressive force 20 mN, tension / compressive force gain 1.2, and initial force amplitude 20 mN. The analysis was performed using the analysis software attached to the device, and the Digimatic Caliper CD-15 type manufactured by Mitsuyoto Co., Ltd. was used for measuring the dimensions of the test piece.

<Store elastic modulus of resin particles (molten viscoelasticity)>
The dynamic viscoelasticity measurement in the present invention was measured by the "PHYSICA MCR301" viscoelasticity measuring device manufactured by Antonio Par and the "CTD450" temperature control system. First, a disk-shaped test piece having a diameter of 25 mm and a thickness of 3 mm was prepared from a resin dried at 90 to 100 ° C. for 3 hours using a hot press machine under the condition of a temperature of 190 to 200 ° C. Next, the test piece was set on a plate of a viscoelasticity measuring device heated to a measurement start temperature of 220 ° C., and heated and melted in a nitrogen atmosphere for 5 minutes. Then, the interval was crushed to 2 mm with a parallel plate having a diameter of 25 mm, and the resin protruding from the plate was removed. After heating for 5 minutes after reaching the measurement start temperature of 220 ± 1 ° C, dynamic viscoelasticity is performed under the conditions of strain 0.025%, frequency 1 Hz, temperature lowering rate 2 ° C / min, measurement interval 30 seconds, and normal force 0N. A viscoelasticity measurement was performed, and the storage elastic modulus in the range of 220 to 80 ° C. was measured.

<Amount of impregnated gas of effervescent particles>
The mass W1 (g) of the obtained effervescent particles was immediately weighed and allowed to stand for 24 hours in an environment with a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5%. After standing, the mass W2 (g) of the effervescent particles was weighed, and the amount of impregnated gas of the effervescent particles was calculated by the following formula.
Amount of impregnated gas (mass%) of effervescent particles = (W1-W2) / W1 × 100

<Volume density of foamed particles>
The foamed particles were weighed with an arbitrary mass W (g) as a measurement sample. After the measurement sample was naturally dropped into the graduated cylinder, the bottom of the graduated cylinder was tapped to make the volume constant, and the apparent volume V (cm ³ ) of the sample was measured. The bulk density of the foamed particles was calculated based on the following formula.
Bulk density (g / cm ³ ) = mass of measurement sample W / volume V of measurement sample

<Average particle size of foamed particles>
The maximum and minimum diameters of the foamed particles were measured with a Digimatic Caliper manufactured by Mitutoyo Co., Ltd., and the average particle diameter (mm) was calculated by the following formula. The average value of the average particle diameters of 10 randomly selected foamed particles was taken as the average particle diameter.
Average particle diameter (mm) = (maximum diameter + minimum diameter) / 2

<Average bubble diameter of foamed particles>
The average bubble diameter of the foamed particles was measured by the following method. Specifically, the foamed particles are divided into two equal parts using a microscope so as to pass through the center of the foamed particles, and the cut surface is "S-3000N" manufactured by Hitachi, Ltd. or "S-3400N" manufactured by Hitachi High-Technologies Corporation. The image was taken with a scanning electron microscope so that the entire cross section of the foamed particles could be seen. The captured image was printed on A4 paper, an arbitrary straight line passing through the center of the cross section of the foamed particles in contact with 20 or more bubbles was drawn, the length L of the straight line was measured, and the number of bubbles N in contact with the straight line was counted. .. Arbitrary straight lines should not touch only at the contacts as much as possible, and if they do touch, they are included in the number of bubbles. If the bubbles were small and difficult to count, the photographs were magnified and measured. The average bubble diameter D of the cross section of the three foamed particles was calculated by the following formula, and the average value of these was taken as the average bubble diameter.
Average chord length t (μm) = line length L / (number of bubbles N x magnification of photo)
Average bubble diameter D (μm) = average chord length t / 0.616

<The closed cell ratio and open cell ratio of foamed particles>
A sample cup of "Air Comparative Hydrometer 1000 Type" manufactured by Tokyo Science Co., Ltd. was prepared, and the total weight A (g) of the foamed particles satisfying about 80% of the sample cup was measured. The volume B (cm ³ ) of the entire foamed particles was measured by the 1-1 / 2-1 atm method using an air comparative hydrometer, and corrected with a standard sphere (large 28.96 cc small 8.58 cc). gone. Subsequently, an empty wire mesh container placed with the lid closed so that the foamed particles did not spill was immersed in water, and the weight C (g) of the empty wire mesh container in the state of being immersed in water was measured. Next, after putting all the foamed particles in the wire mesh container, the wire mesh container is immersed in water, and the container is shaken several times to remove air bubbles adhering to the container and the foamed particles. The weight D (g) of the wire mesh container in a state of being immersed in water and the total amount of foamed particles placed in the wire mesh container was measured. An "electronic balance HB3000" (minimum scale 0.01 g) manufactured by Yamato Scale Co., Ltd. was used for weight measurement in water. Then, the apparent volume E (cm ³ ) of the foamed particles was calculated by the following formula. Based on this apparent volume E (cm ³ ) and the volume B (cm ³ ) of the entire foamed particles, the open cell ratio of the foamed particles was calculated by the following formula 1 and the closed cell ratio was calculated from the formula 2. The volume of 1 g of water was 1 cm ³ , the resin density was 1.17 g / cm ³ (F), and the number of tests was 5. The sample was stored in advance in a JIS K710-1999 symbol 23/50, class 2 environment for 16 hours, and then measured in the same environment.
Equation 1
Apparent volume E (cm ³ ) = A + (CD)
Open cell ratio (%) = 100 × (EB) / E
Equation 2
Closed cell ratio (%) = 100 × (B- (A / F)) / E

<Amount of impregnated gas of foamed particles>
First, the mass W1 (g) of the foamed particles before applying the internal pressure was measured. Next, the mass W2 (g) of the foamed particles after applying the internal pressure was measured. The amount of impregnated gas of the foamed particles was calculated by the following formula.
Amount of impregnated gas (mass%) of foamed particles = (W2-W1) / W2 × 100

<Density of foam molded product>
Immediately after molding, the foamed molded product was dried at a temperature of 40 ° C. for 12 hours, and after drying, the state was adjusted for 72 hours in an environment of a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5%. The mass W (g) of the foamed molded product whose condition was adjusted was measured to two decimal places, and the outer dimensions were measured to 1/100 mm with a Digimatic caliper manufactured by Mitutoyo Co., Ltd. to obtain the apparent volume V (cm ³ ). .. The density of the foam molded product was calculated by the following formula.
Foam molded body density (g / cm ³ ) = Foamed molded body mass W / apparent volume V

<Asker C hardness of foam molded product>
Asker C hardness is determined by adjusting the condition of a test piece with a smooth surface and a thickness of 10 mm or more for 72 hours or more in an environment with a temperature of 23 ± 2 ° C and a humidity of 50 ± 5%. Measured using a "C-shaped" hardness tester. The pressure surface was brought into close contact with the press needle so that it was perpendicular to the smooth measurement surface of the test piece, and the scale was immediately read. Five points of the sample were measured while avoiding the fusion surface between the foamed particles, and the average value of these was taken as the Asker C hardness.

<Repulsive modulus of foam molded product>
Measured according to JIS K 6400-3: 2011. A sample cut out from the same foam, which was condition-adjusted for 72 hours or more in an environment with a temperature of 23 ± 2 ° C and a humidity of 50 ± 5%, was placed in a “FR-2” rebound resilience tester manufactured by Polymer Instruments Co., Ltd. and had a thickness of 40 mm or more. A copper ball (φ5 / 8 inch, 16.3 g) is freely dropped from a height (a) of 500 mm, and the height (b) at the time of reaching the maximum repulsion is read and the formula is used. The elastic modulus (%) was calculated by (b) / (a) × 100. However, the same test piece was used for three measurements, and the average value of these was taken as the rebound resilience.

<Fusion rate of foam molded product>
A cut line having a depth of about 5 mm was made on the surface of the foam molded product with a cutter knife along a straight line connecting the centers of the pair of long sides, and then the foam molded product was divided into two along the cut line. For the foamed particles having a fracture surface of the split foamed product, an arbitrary range including 50 foamed particles is set, and the number of foamed particles (a) broken in the foamed particles within this range is determined. The number of foamed particles (b) broken at the interface between the foamed particles was counted, and the fusion rate F (%) was calculated by the following formula.
Fusing rate F (%) = a / (a + b) × 100

<Example 1>
(1) Resin particles Ester-based elastomer dried at 100 ° C for 3 hours in a polyethylene standard bag (trade name: "Perprene P-75M", manufactured by Toyobo Co., Ltd., hard segment: polybutylene terephthalate and polybutylene isophthalate, soft segment : 100 parts by mass of aliphatic polyether) and 0.1 part by mass of wax (ethylene bisstearic acid amide, trade name: "Kao Wax EBFF", manufactured by Kao Co., Ltd.) are added and mixed, and then supplied to a twin-screw extruder. Then, it was melt-kneaded at 180 to 250 ° C. Next, after cooling the molten resin to adjust the viscosity, the resin extruded from the nozzle die (diameter: 3 mm) attached to the tip of the twin-screw extruder is cooled with water at 20 to 60 ° C. The solidified resin was cut to obtain resin particles. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles In an autoclave with a stirrer with an internal volume of 5 L, 500 g (100 parts by mass) of resin particles, 3.0 L of distilled water, a surfactant (straight chain alkylbenzene sulfonate sodium, trade name: "Nurex R" (Manufactured by Yuka Sangyo Co., Ltd.) 4 g was added and sealed, and then 20 parts by mass of the foaming agent butane (normal butane: isobutane = 7: 3) was press-fitted together with nitrogen gas in a stirred state. The autoclave was then heated at 100 ° C. for 2 hours and cooled to 25 ° C. After the cooling was completed, the autoclave was decompressed, and the surfactant was immediately washed with distilled water and dehydrated to obtain effervescent particles. The amount of impregnated gas of the effervescent particles was 6.7% by mass.
(3) Foamed particles Apply 0.3 parts by mass of an anti-adhesion agent (polyoxyethylene polyoxypropylene glycol, trade name: "Epan 450", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to 500 g (100 parts by mass) of foamable particles. Then, the particles were put into a cylindrical prefoaming machine with an internal volume of 50 L and heated with steam having a gauge pressure of 0.14 MPa while stirring to obtain foamed particles.
(4) Effervescent molded body The effervescent particles were put into an autoclave, compressed air having a gauge pressure of 0.5 MPa was press-fitted, and then allowed to stand at room temperature for 18 hours to impregnate the effervescent particles with nitrogen gas (internal pressure applying step). The amount of nitrogen impregnated was 0.9% by mass.
The foamed particles were immediately taken out from the autoclave, immediately filled in a molding cavity having a size of 300 mm × 50 mm × thickness 25 mm having steam holes, and heat-molded with steam having a gauge pressure of 0.16 MPa to obtain a foamed molded product. ..

<Example 2>
Ester-based elastomer (trade name: "Perprene P-75M", manufactured by Toyobo Co., Ltd., hard segment: polybutylene terephthalate and polybutylene isophthalate, soft segment: aliphatic polyether) 100 parts by mass and wax (ethylene bisstearic acid amide, Product name: "Kao Wax EBFF", manufactured by Kao Co., Ltd.) 0.3 parts by mass was supplied to a single-screw extruder and melt-kneaded at 180 to 280 ° C. Next, after cooling the molten ester-based elastomer to adjust the viscosity, the resin is removed from each nozzle of the multi-nozzle mold (having 8 nozzles with a diameter of 1.3 mm) attached to the front end of the single-screw extruder. It was extruded and cut in water at 30-50 ° C. The obtained resin particles had a particle length L of 1.4 to 1.8 mm and an average particle diameter D of 1.4 to 1.8 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1. The amount of impregnated gas of the effervescent particles was 7.2% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded article A foam molded article was obtained in the same manner as in Example 1 except that the size of the cavity was changed to 300 mm × 400 × thickness 11 mm. The amount of nitrogen impregnated was 0.9% by mass.

<Example 3>
(1) Resin particles Same as Example 1 except that the wax type was changed to calcium stearate (trade name: "Calcium stearate SC-PF", manufactured by Sakai Chemical Industry Co., Ltd.) and the amount of wax added was changed to 0.3 parts by mass. Resin particles were obtained by the method. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1. The amount of impregnated gas of the effervescent particles was 6.4% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 1.0% by mass.

<Example 4>
(1) Resin particles Resin particles were obtained in the same manner as in Example 1 except that the amount of wax (ethylene bisstearic acid amide) added was changed to 0.5 parts by mass. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1. The amount of impregnated gas of the effervescent particles was 6.4% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.8% by mass.

<Example 5>
(1) Resin Particles Resin particles were obtained by the same method as in Example 1 except that the amount of wax (ethylene bisstearic acid amide) added was changed to 1 part by mass. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1. The amount of impregnated gas of the effervescent particles was 6.5% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.9% by mass.

<Example 6>
(1) Resin particles Resin particles are prepared by the same method as in Example 1 except that the wax type is stearic acid amide (trade name: "fatty acid amide S", manufactured by Kao Corporation) and the amount of wax added is changed to 3 parts by mass. Obtained. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1. The amount of impregnated gas of the effervescent particles was 6.3% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.9% by mass.

<Example 7>
(1) Resin Particles Resin particles were obtained by the same method as in Example 1 except that the amount of wax (ethylene bisstearic acid amide) added was changed to 5 parts by mass. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1. The amount of impregnated gas of the effervescent particles was 6.1% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.7% by mass.

<Example 8>
(1) Effervescent particles 500 g of the resin particles prepared in Example 7 were put into an autoclave having an internal volume of 5 L, sealed, and then pressurized from atmospheric pressure to a gauge pressure of 4 MPa with carbon dioxide (foaming agent). Next, the autoclave was allowed to stand at room temperature for 24 hours and then depressurized to obtain effervescent particles. The amount of impregnated gas of the effervescent particles was 5.1% by mass.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(3) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.7% by mass.

<Comparative Example 1>
(1) Resin particles Resin particles were obtained in the same manner as in Example 1 except that wax (ethylene bisstearic acid amide) was not added. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1. The amount of impregnated gas of the effervescent particles was 6.3% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.9% by mass.

<Comparative Example 2>
(1) Effervescent particles 500 g of the resin particles prepared in Comparative Example 1 was put into an autoclave having an internal volume of 5 L, sealed, and then pressurized from atmospheric pressure to a gauge pressure of 4 MPa with carbon dioxide (foaming agent). Next, the autoclave was allowed to stand at room temperature for 24 hours and then depressurized to obtain effervescent particles. The amount of impregnated gas of the effervescent particles was 5.2% by mass.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(3) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.7% by mass.

<Comparative Example 3>
(1) Resin Particles Resin particles were obtained in the same manner as in Example 1 except that the amount of wax (ethylene bisstearic acid amide) added was changed to 7 parts by mass. The obtained resin particles had a particle length L of 2 to 3 mm and an average particle diameter D of 2 to 2.5 mm.
(2) Effervescent particles Effervescent particles were obtained in the same manner as in Example 8. The amount of impregnated gas of the effervescent particles was 4.9% by mass.
(3) Effervescent particles Effervescent particles were obtained in the same manner as in Example 1.
(4) Foam molded product A foam molded product was obtained in the same manner as in Example 1. The amount of nitrogen impregnated was 0.7% by mass. Compared with the foam molded products of Comparative Examples 1 and 2 to which no wax was added, the rebound resilience was significantly reduced, and the rebound resilience was less than 50%.
Table 1 summarizes various physical property values of Examples 1 to 8 and Comparative Examples 1 to 3. Further, cross-sectional photographs of the foamed particles of Examples 1 to 8 and Comparative Examples 1 to 3 are shown in FIGS. 1 to 11.

From Table 1, it can be seen that the foam molded products of Examples 1 to 8 have improved fusion properties.

Claims (8)

It is composed of a resin composition containing an ester-based elastomer as a base resin and a wax as a fusion improver.
The wax is selected from a higher fatty acid amide having 12 to 22 carbon atoms, a higher fatty acid bisamide having 25 to 46 carbon atoms, and a higher fatty acid salt having 12 to 22 carbon atoms, and is 0 with respect to 100 parts by mass of the ester-based elastomer. 0.01 to 5 parts by mass of wax-containing foamed particles. The resin composition is
(I) Shore D hardness of 0 to 65 (ii) Melting point of 100 to 200 ° C. (iii) Storage elastic modulus measured by melt viscoelasticity measurement at a frequency of 1 Hz at a crystallization temperature Tc is 1 × 10 ⁶ to 2 × 10 ⁷ Pa. Range (iv) According to claim 1 , the storage elastic modulus by solid viscoelasticity measurement at a frequency of 1 Hz at a Vicat softening temperature Tv-10 ° C. has at least one of the physical properties in the range of 1 × 10 ⁷ to 2 × 10 ⁸ Pa. The wax-containing foam particles described. The wax-containing foamed particles
(I) Bulk density of 0.02 to 0.4 g / cm ³ (ii) Average bubble diameter of 10 to 300 μm (iii) 60 to 100% closed cell ratio (iv) Average particle diameter of 1.5 to 15 mm The wax-containing foamed particles according to claim 1 or 2 , which have at least one of the physical characteristics. The method for producing wax-containing foamed particles according to any one of claims 1 to 3 .
A method for producing wax-containing foamed particles, which comprises a step of impregnating resin particles containing the ester-based elastomer and the wax with a foaming agent to obtain foamable particles, and a step of foaming the foamable particles. .. A foamed molded product obtained by in-mold foaming of the wax-containing foamed particles according to any one of claims 1 to 3 . The foam molded product
(I) The 5 ^. Foam molded body. The foam molded body according to claim 5 or 6 , wherein the foam molded body is used as a building material, a shoe member, a sporting goods, a cushioning material, a seat cushion, or an automobile member. The method for producing a foam molded product according to any one of claims 5 to 7 .
Manufacture of a foamed molded product comprising a step of in-mold foaming the wax-containing foamed particles according to any one of claims 1 to 3 using steam having a gauge pressure of 0.05 to 0.4 MPa as a heating medium. Method.

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