JP2019065115A - High-gloss foamed particles, foamed molding, and method for producing them - Google Patents

Abstract

To provide high-gloss foamed particles capable of providing a foamed molding having a surface with high glossiness.SOLUTION: High-gloss foamed particles are formed of a resin composition containing an ester-based elastomer as a base material resin, where the high-gloss foamed particles have a plurality of air bubbles satisfying a relationship of A>B (A is average bubble diameter of surface layer part, and B is average bubble diameter of center part), the average bubble diameter of the surface layer part is 80-400 μm, and the average bubble diameter of the center part is 10-200 μm. In the high-gloss foamed particles, A and B satisfy a relationship of A/B>1. In the high-gloss foamed particles, the resin composition has at least one of storage elastic modulus by solid viscoelasticity measurement at Vicat softening temperature Tv-10°C of 1×10to 2×10Pa, and storage elastic modulus at a crystallization temperature Tc of 1×10to 2×10Pa.SELECTED DRAWING: Figure 1

Description

  The present invention relates to high gloss foam particles, foam moldings and methods for their production. More particularly, the present invention relates to high gloss foam particles capable of providing a foam having a high gloss surface, a method for producing the same, a foam having a high gloss surface, and a method for producing them.

Conventionally, as a shock absorbing material or a packing material, a foam molded article in which a plurality of foam particles made of polystyrene, polypropylene or the like are fused is widely used. A foam molded article in which a plurality of foam particles are fused is advantageous in that it can form a complicated shape as compared to a foam molded article by extrusion foaming. There has been a problem that a foam molded article made of polystyrene, polypropylene or the like is difficult to use in applications where high impact resilience is required. Therefore, a foam molded article that can realize high impact resilience has been required.
According to the said request | requirement, the foaming molding using an amide-type elastomer foam particle is proposed by Unexamined-Japanese-Patent No. 2016-190989 (patent document 1).

JP, 2016-190989, A

The inventors of the present invention have found that, in addition to the amide-based elastomer, foamed particles can be produced even with an ester-based elastomer having excellent resilience.
By the way, when using a foaming particle or the foaming molding obtained from this for an external structure which can be noticed visually, high glossiness may be calculated | required by the surface in order to improve design property. Examples of the method for imparting gloss include a method of mixing a gloss imparting material (pearl pigment or metal powder) with a base resin, and a method of coating the surface of a foamed particle or a foam molded article with a paint containing a gloss imparting material. Be However, the former method has a problem that it is difficult to control the cell diameter because the gloss-imparting material acts as a cell nucleating agent at the time of foaming. In the latter method, there is a problem that the cost increases due to the addition of the coating process and the durability of the coating due to peeling is inferior.

  The inventors of the present invention were surprised that, as a result of intensive studies, if foam particles having an average cell diameter between the surface layer portion and the center portion have a specific relationship, a foam molded article having a surface with high glossiness can be provided. The present invention has been made by finding out also.

Thus, according to the present invention, high-gloss foam particles composed of a resin composition containing an ester elastomer as a base resin,
The high gloss foam particles have a plurality of cells satisfying the relationship of A> B (A is an average cell diameter of the surface layer portion and B is an average cell diameter of a center portion),
The high gloss foam particles are provided, wherein the average cell diameter of the surface layer portion is 80 to 400 μm, and the average cell diameter of the central portion is 10 to 200 μm.
Further, according to the present invention, there is provided a method of producing the above-mentioned high gloss foam particles,
A method of producing high-gloss foam particles, comprising the steps of: impregnating a resin particle containing the ester elastomer as a base resin with a foaming agent to obtain foamable particles; and foaming the foamable particles. Is provided.
Furthermore, according to the present invention, there is provided a foam molded article obtained by in-mold foaming of the high gloss foam particles.
Further, according to the present invention, there is provided a method of producing the above-mentioned foam molded article,
A process for producing a foam molded article is provided, including the step of in-mold foaming of the high gloss foam particles using a steam having a gauge pressure of 0.05 to 0.4 MPa as a heating medium.

  The high gloss foam particles of the present invention can provide a foam molded article having a high gloss surface.

In addition, in any of the following cases, high gloss foam particles can be provided which can produce a foam molded article having a surface having a higher glossiness.
(1) A and B satisfy the relationship of A / B> 1.5.
(2) The resin composition is (i) a storage elastic modulus by solid viscoelasticity at a Vicat softening temperature Tv-10 ° C. of 1 × 10 ⁷ to 2 × 10 ⁸ Pa, and (ii) 1 × 10 ⁶ to 2 × 10 ^It has any physical properties of storage elastic modulus by melt viscoelasticity measurement at a crystallization temperature Tc of ⁷ Pa.
(3) High gloss foam particles,
(I) Bulk density of 0.02 to 0.4 g / cm ³ (ii) It has at least physical properties of any of average particle diameter of 1.5 to 15 mm.

It is a cross-sectional photograph of the foaming particle of Example 1. 7 is a cross-sectional photograph of the expanded beads of Example 2. 7 is a cross-sectional photograph of the foamed particles of Example 3. It is a cross-sectional photograph of the foaming particle of comparative example 1.

(High gloss foam particles)
The high gloss foamed particles (hereinafter simply referred to as foamed particles) of the present invention are composed of a resin composition containing an ester elastomer as a base resin. In the present specification, the inventors consider that high glossiness means a state in which the degree of reflection in the regular reflection direction is high and the resin has gloss.

(1) Ester-Based Elastomer The ester-based elastomer is not particularly limited as long as it provides a foam. 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. You may be comprised from 2 components of a dicarboxylic acid component, and a dicarboxylic acid component and a diol component.
Examples of the dicarboxylic acid component include components derived from aliphatic dicarboxylic acids such as oxalic acid, malonic acid and succinic acid and derivatives thereof, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid and derivatives thereof.
As a diol component, C _2-10 alkylene glycol such as ethylene glycol, propylene glycol, butanediol (eg, 1,4-butanediol), (poly) oxy C _2-10 alkylene glycol, C _5-12 cycloalkanediol And bisphenols or alkylene oxide adducts thereof. The hard segment may have crystallinity.

As the soft segment, polyester type and / or polyether type segments 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 glycol) Aliphatic polyesters such as polycondensates with (poly) oxy C _2-10 alkylene glycols, polycondensates of oxycarboxylic acids and ring-opening polymers of lactones (C _3-12 lactones such as ε-caprolactone) It 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 and polybutylene adipate and C _6-12 alkanedicarboxylic 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 10,000, and may be in the range of 300 to 8,000.
Soft segments of polyether type include segments derived from aliphatic polyethers such as polyalkylene glycols (eg, 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, and may be in the range of 300 to 5000.

The soft segment is a polyester having a polyether unit such as a copolymer of aliphatic polyester and polyether (polyether-polyester), a polyether such as polyoxyalkylene glycol (eg, polyoxytetramethylene glycol) It may be a segment derived from a polyester of and aliphatic dicarboxylic acid.
The mass ratio of the hard segment to 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: 60-80: 20, and may be 40: 60-75: 25.
When the dicarboxylic acid component is a terephthalic acid component and a dicarboxylic acid component other than that, the ester elastomer contains a hard segment in a proportion of 30 to 80% by mass, and the dicarboxylic acid component other than the terephthalic acid component is 5 You may contain in the ratio of -30 mass%. The proportion 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 dicarboxylic acid components other than a terephthalic acid component are isophthalic acid components. By including the isophthalic acid component, the crystallinity of the elastomer tends to decrease, and the foam moldability can be improved to obtain a foam having a lower density.
As ester-based elastomers, Pelprene series manufactured by Toyobo Co., Ltd. and VYLON series can be suitably used. In particular, it is preferable to use the Pelprene series.

The resin composition has a storage modulus of 1 × 10 ⁷ to 2 × 10 ⁸ Pa (value determined by solid viscoelasticity measurement at Vicat softening temperature Tv−10 ° C.). By having a storage elastic modulus (solid viscoelasticity) within this range, it is possible to provide foam particles capable of producing a foam having a high impact resilience. The storage elastic modulus (solid viscoelasticity) may be in the range of 1 × 10 ^{7 to} 1.5 × 10 ⁸ Pa, or in the range of 1 × 10 ⁷ to 1 × 10 ⁸ Pa, or 1 × It may be in the range of 10 ⁷ to 8 × 10 ⁷ Pa.
Moreover, it is preferable that the storage elastic modulus by melt-viscoelasticity measurement in crystallization temperature Tc-10 degreeC has the range of 1 * 10 < ⁶ > -2 * 10 < ⁷ > Pa in a resin composition. When the storage elastic modulus (melt viscoelasticity) is less than 1 × 10 ⁶ Pa, the expanded shape may not be maintained in the cooling process after foaming, and the resin may shrink. When it is larger than 2 × 10 ⁷ Pa, softening during foaming becomes difficult, and a desired expansion ratio (density) may not be obtained. The storage elastic modulus (melt viscoelasticity) may be in the range of 1 × 10 ^{6 to} 1.5 × 10 ⁷ Pa, or in the range of 1 × 10 ⁶ to 1 × 10 ⁷ Pa, or 3 × It may be in the range of 10 ⁶ to 1 × 10 ⁷ Pa.

(2) Base Resin In addition to the ester elastomer, another resin may be contained in the base resin 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 material composition may further contain a flame retardant, a colorant, an antistatic agent, a spreading agent, a plasticizer, a flame retardant auxiliary, a crosslinking agent, a filler, a lubricant, and the like.
Examples of the flame retardant include hexabromocyclododecane and triallyl isocyanurate hexabromide.
Examples of the colorant include inorganic pigments such as carbon black, graphite and titanium oxide, organic pigments such as phthalocyanine blue, quinacridone red and isoindolinone yellow, and special pigments such as metal powder and pearl.
Examples of the antistatic agent include polyoxyethylene alkylphenol ether and stearic acid monoglyceride.
As the spreading agent, polybutene, polyethylene glycol, silicone oil and the like can be mentioned.

(3) Physical Properties of Foamed Particles The foamed particles have a plurality of cells that satisfy the relationship A> B (A is the average cell diameter of the surface layer portion and B is the average cell diameter of the center portion). By having this relationship, it is possible to provide a foam molded article having a surface with a higher gloss than foam particles having a relationship of A ≦ B. The inventors speculate that the reason is that the diffuse reflection of light can be reduced.
In the present specification, the surface layer portion means an area of up to about 30% of the radius of the foam particle from the surface of the foam particle to the center. On the other hand, the central part means an area of up to about 70% of the radius of the foam particle from the center of the foam particle to the surface.
Moreover, the average bubble diameter of a surface layer part is 80-400 micrometers. On the other hand, the average bubble diameter at the central portion is 10 to 200 μm. When the average cell diameter of the surface layer portion is less than 80 μm, sufficient glossiness may not be obtained. If it is larger than 400 μm, the formability may be deteriorated. If the average cell diameter at the center is less than 10 μm, it may shrink to cause appearance defects. When it is larger than 200 μm, fusion between the foamed particles may be deteriorated at the time of molding, and the strength may be reduced. The average cell diameter of the surface layer is preferably 80 to 350 μm, and more preferably 90 to 350 μm. On the other hand, the average cell diameter of the central portion is preferably 20 to 200 μm, and more preferably 30 to 200 μm.
Furthermore, A and B preferably have a relationship of A / B> 1.5. This relationship means that the bubbles located in the surface layer portion of the foamed particles have a considerably larger average bubble diameter than the bubbles located in the center portion.

The foam particles are
(I) Bulk density of 0.02 to 0.4 g / cm ³ (ii) It is preferable to have at least physical properties of any of average particle sizes of 1.5 to 15 mm.
If the bulk density is less than 0.02 g / cm ³ , it may shrink to cause appearance defects or decrease in strength. When it is larger than 0.4 g / cm ³ , it may not be possible to obtain a lightweight foam. The bulk density may be in the range of 0.04~0.4g / cm ^3, it may be in the range of ^{0.06~0.4g / cm 3, 0.06~0.3g / cm} 3 It may be in the range of
If the average particle size is less than 1.5 mm, it may be difficult to produce the foamed particle itself, and the production cost may be increased. When it is larger than 15 mm, the filling property to the mold may be reduced when producing the foam molded body by in-mold molding. The average particle size may be in the range of 1.5 to 12 mm, or in the range of 1.5 to 9 mm.

(Method for producing high gloss foam particles)
The foamed particles can be produced by a method including the steps of impregnating resin particles containing an ester-based elastomer (base resin) with a foaming agent to obtain expandable particles, and expanding the expandable particles.

(1) Expandable Particles Expandable particles can be obtained through the step of impregnating resin particles with a foaming agent to obtain expandable particles (impregnation step).
The blowing agent may be an organic gas or an inorganic gas. As the inorganic gas, there are air, nitrogen, carbon dioxide (carbon dioxide gas) and the like. Examples of the organic gas include hydrocarbons such as propane, butane and pentane, and fluorine-based blowing agents. Only one type of the above-mentioned foaming agent may be used, or two or more types 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 the amount is less than 1 part by mass, the foaming power is low, and it is difficult to increase the foaming ratio. When the content of the foaming agent exceeds 12 parts by mass, the plasticizing effect is increased, and shrinkage may occur during foaming, so that good foamed particles may not be obtained. The amount of blowing agent may be 5 to 12 parts by weight. Within this range, the foaming power can be sufficiently enhanced, and the foam can be further enhanced.
A publicly known method can be used as a method of impregnating resin particles with a foaming agent. For example, resin particles, a dispersing agent and water are supplied and stirred in an autoclave to disperse the resin particles in water to produce a dispersion, and a foaming agent is pressed into the dispersion to obtain resin particles in the resin particles. Are impregnated with a blowing 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.

When the temperature at which the foaming agent is impregnated into the resin particles is low, the time required for impregnating the resin particles with the foaming agent may be prolonged, and the production efficiency may be lowered. Moreover, when high, resin particles may fuse and a bond grain may generate | occur | produce. 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 cell regulator may be used in combination with the foaming agent.
Examples of the foaming assistant (plasticizer) include diisobutyl adipate, toluene, cyclohexane, ethylbenzene and the like.

Examples of the cell regulator include higher fatty acid amides, higher fatty acid bisamides, higher fatty acid salts, inorganic cell nucleating agents, and the like. These cell regulators may be used in combination of two or more.
As higher fatty acid amides, stearic acid amide, 12-hydroxystearic acid amide and the like can be mentioned.
Examples of higher fatty acid bisamides include ethylenebisstearic acid amide and methylenebisstearic acid amide.
Higher fatty acid salts include calcium stearate.
As the inorganic cell nucleating agent, talc, calcium silicate, synthetically or naturally produced silicon dioxide and the like can be mentioned.
In addition to the above, it is also possible to use a foam control agent which also plays a role as a chemical foam. As such a foam control agent, sodium bicarbonate citric acid, sodium hydrogencarbonate, azodicarbonamide, dinitrosopentamethylenetetramine, benzenesulfonyl hydrazide, hydrazodicarbonamide and the like can be mentioned.
The content of the cell regulator 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 expandable particles. If the amount of the cell regulator is less than 0.005 parts by mass, it may be difficult to control the cell diameter. When the amount of the cell regulator is more than 2 parts by mass, the physical properties of the resin may be changed, for example, a decrease in the strength of the molded body may occur.

(2) Resin Particles The shape of the resin particles is not particularly limited, and examples thereof include a spherical shape, an oval spherical shape (egg shape), a cylindrical shape, a prismatic shape, a pellet shape or a granular shape.
The resin particles may have a length of 0.5 to 5 mm and an average diameter of 0.5 to 5 mm. If the length is less than 0.5 mm and the average diameter is less than 0.5 mm, it may be difficult to foam since the gas retention property in the case of forming the expandable particles is low. When the length is more than 5 mm and the average diameter is more than 5 mm, when the foam is made, since the heat is not transmitted to the inside, a core of the foam particle may be generated. Here, the length L and the average diameter D of the resin particles are measured using a caliper as follows. The length of the resin particle in the extrusion direction at the time of re-pelletizing is taken as 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 taken as the average diameter D.

(3) Expanded Particles Expanded particles can be obtained through the step of expanding expandable particles (expanding step).
The shape of the foamed particles is not particularly limited, and examples thereof include a spherical shape, an oval spherical shape (egg shape), a cylindrical 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 foamable particles can be foamed to obtain foamable particles.

In the foaming step, a cohesion inhibitor may be added to the foamable particles. The addition amount of the cohesion inhibitor 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 expandable particles. If the cohesion preventing agent is less than 0.03 parts by mass, the cohesion preventing effect may not be sufficiently exhibited. If the cohesion preventing agent is more than 0.3 parts by mass, the strength of the foam molded article may decrease or the cleaning cost may increase.
Powdered metal soaps such as zinc stearate, calcium carbonate and aluminum hydroxide may be applied to the surface of the foamable particles before foaming. This application can reduce the bonding between the expandable particles in the expansion step. Moreover, you may apply | coat surface treatment agents, such as an antistatic agent and a spreading agent.

(Foam molded body)
(1) Various physical properties The foamed molded article 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 to cause appearance defects or decrease in strength. Density may be in the range of 0.04~0.4g / cm ^3, it may be in the range of 0.06~0.4g / cm ^3, the 0.06~0.3g / cm ³ It may be a range.
The foamed molded article may have a 50 to 100% impact resilience. If the impact resilience is lower than 50%, it will be difficult to use in applications where impact resilience is required.
The foam molding may have an Asker C hardness of 20-65. If the Asker C hardness is less than 20, the shape stability of the foam molded article may be reduced. When it is larger than 65, for example, sufficient resilience and flexibility may not be obtained. Asker C hardness may be in the range of 20 to 60, and may be in the range of 20 to 55.
The foam molded article can be used, for example, as a building material, a shoe member, a sporting goods, a shock absorbing material, a seat cushion, an automobile member and the like. Specifically, midsoles, insoles and outsoles of shoes, core materials for batting products such as rackets and bats, armors for sports products such as pads and protectors, and medical and nursing care such as pads and protectors・ Welfare and health care products, tire core materials such as bicycles and wheelchairs, interior materials of transport equipment such as automobiles, sheet core materials of shock absorbers, vibration absorption members, shock absorbers such as fenders and floats, toys, It can be used for flooring, wall materials, railway cars, airplanes, beds, cushions, etc.
The foam molding may take any suitable shape depending on the application.

(2) Manufacturing method The manufacturing method of a foaming molding includes the process of carrying out the in-mold foaming of the foaming particle by making the water vapor | steam of gauge pressure 0.05-0.4MPa into a heating medium. For example, filling foam particles in a closed mold having a large number of pores, heating foam the foam particles with steam, filling voids between the foam particles, fusing the foam particles to one another, and integrating them. It can be obtained by At that time, for example, the density of the foam molded article can be adjusted by adjusting the filling amount of the foam particles in the mold. When the gauge pressure of the water vapor is less than 0.05 MPa, it is difficult to foam the foam particles in the mold, and the fusion between the foam particles is reduced, which may make it impossible to impart sufficient strength to the foam. When it is higher than 0.4 MPa, the foam molded product may shrink and a foam molded product having a good appearance may not be obtained. The gauge pressure of the steam may be 0.05 to 0.35 MPa, 0.05 to 0.3 MPa, or 0.1 to 0.3 MPa.
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 foaming particles (internal pressure application step). By improving the foaming power, the adhesion between the foamed particles is improved at the time of in-mold foaming, and the foam molded article has further excellent mechanical strength. In addition, as an inert gas, a carbon dioxide, nitrogen, helium, argon etc. are mentioned, for example.
As a method of impregnating the foamed particles with the inert gas and the like, for example, a method of impregnating the foamed particles with the inert gas and the like by placing the foamed particles under an atmosphere of inert gas having a pressure higher than normal pressure It can be mentioned. The foam particles may be impregnated with an inert gas or the like before filling into the mold, but after being filled with the foam particles into the mold, the foam particles are impregnated by being placed under an atmosphere such as inert gas together with the mold It is also good. When the inert gas is nitrogen, the foamed particles may be left in a nitrogen atmosphere with a gauge pressure of 0.1 to 2 MPa for 20 minutes to 24 hours.

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 it is, but the foamed particles are heated and foamed before filling in the mold to reduce After being made into bulk density foam particles, they may be filled in a mold for heating and foaming. By using such low bulk density foam particles, a low density foam can be obtained.
Moreover, when using a cohesion inhibiting agent at the time of manufacture of a foaming particle, you may perform shaping | molding with a cohesion inhibiting agent adhering to a foaming particle at the time of manufacture of a foaming molding. In addition, in order to promote the fusion between the expanded particles, the coalescent agent may be washed and removed before the molding step.

EXAMPLES The present invention will next be described in more detail by way of examples, which should not be construed as limiting the invention thereto.
<Shore D hardness of resin particles>
The resin particles dried at 100 ° C. for 3 hours were heat-pressed at a temperature of melting point Tm + 30 ° C. to produce a smooth film having a thickness of 3 mm or more. This was conditioned for 24 hours or more under an environment of temperature 23 ± 2 ° C. and humidity 50 ± 5%, and then measured using a “Teclock Durometer Type D” hardness tester manufactured by Tek Co., Ltd. The pressure surface was brought into close contact so that the needle was perpendicular to the test piece measurement surface, and the scale was read immediately. Five places of a sample were measured, and these average values were made into Shore D hardness.

<Melting point Tm of resin particles, crystallization temperature Tc, and crystallization heat amount>
The melting point and the crystallization temperature were measured by the methods described in JIS K7121: 1987 and JIS K 7121: 2012 “Method for measuring transition temperature of plastic”. However, the sampling method and temperature conditions were as follows. The sample was filled with 5 to 7 mg so that the bottom of the aluminum measurement container was not separated, and then an aluminum lid was attached. Next, after lowering the temperature from 30 ° C to -70 ° C using a nitrogen gas flow rate of 20 mL / min using “DSC7000X, AS-3” manufactured by Hitachi High-Tech Science Co. or “DSC6220” manufactured by SII Nanotechnology Inc. Hold for 10 minutes, increase temperature from -70 ° C to 220 ° C (first temperature increase), hold for 10 minutes, decrease temperature from 220 ° C to -70 ° C (cooling), increase temperature from -70 ° C to 220 ° C after holding for 10 minutes A DSC curve was obtained when (the second temperature rise). In addition, all temperature rising / falling was performed at a rate of 10 ° C./min, and alumina was used as a reference substance. 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 heating process using analysis software attached to the apparatus.
Further, the crystallization temperature was a value obtained by reading the temperature at the top of the crystallization peak on the highest temperature side observed in the cooling process using analysis software attached to the apparatus.
The heat of crystallization was measured by the method described in JIS K 7122: 1987, JIS K 7122: 2012 “Method of measuring heat of transition of plastic”. The heat of crystallization of the crystallization peak at the highest temperature in the cooling process is the point at which the DSC curve leaves the baseline at the high temperature side and the point at which the DSC curve returns to the baseline again at the low temperature side And the area of the part surrounded by the DSC curve.

<Vicat softening temperature Tv of resin particles>
It measured based on A method of JISK7206: 2016 "plastics-thermoplastics-how to obtain | require Vicat softening temperature (VST)." The resin particles dried at 100 ° C. for 3 hours were heat pressed at a melting point Tm + 30 ° C. to prepare a test piece of 10 mm × 10 mm × 5 mm thickness. The measurement was performed three times under the conditions of a temperature increase rate of 50 ° C./hour and a test load of 10 N using a “HAD-6 type” heat distortion tester manufactured by Yasuda Seiki Seisakusho Co., Ltd., and the average value thereof was taken as the Vicat softening temperature.

<Storage elastic modulus of resin particles (solid viscoelasticity)>
The resin dried at 90 to 100 ° C. for 3 hours was heated at a temperature of 190 to 200 ° C. to prepare a strip-like sample having a length of 120 mm, a width of 10 mm and a thickness of 0.7 to 10 mm. For the solid viscoelasticity measurement apparatus, “EXSTRAR DMS 6100” viscoelasticity spectrometer manufactured by SII Nanotechnology Inc. was used. The sample is sampled to a length of 40 to 50 mm, frequency 1 Hz, temperature rising rate 5 ° C./min, measurement temperature 30 ° C. to 260 ° C., chuck interval 20 mm, strain amplitude 5 μm, minimum tension / frequency under nitrogen atmosphere in tension control mode It measured on the conditions of 20 mN of compressive force, tension / compression force gain 1.2, and 20 mN of force amplitude initial values. The analysis used analysis software attached to the device.

<Storage elastic modulus of resin particles (melt viscoelasticity)>
The dynamic viscoelasticity measurement in the present invention was measured by "PHYSICA MCR 301" viscoelasticity measurement apparatus and "CTD 450" temperature control system manufactured by Anton Paar. First, a disk-shaped test piece of 25 mm in diameter and 3 mm in thickness was produced from the resin dried at 90 to 100 ° C. for 3 hours with a heat press at 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 for 5 minutes under a nitrogen atmosphere. Then, the space | interval was crushed to 2 mm with the parallel plate of diameter 25 mm, and the resin which protruded from the plate was removed. After heating for 5 minutes after reaching the measurement start temperature of 220 ± 1 ° C, the dynamic viscosity under the conditions of strain 0.025%, frequency 1 Hz, temperature decrease rate 2 ° C / minute, measurement interval 30 seconds, normal force 0N Elastic measurements were taken to determine storage modulus in the range of 220-80 ° C.

<Immersion gas amount of expandable particles>
The mass W1 (g) of the obtained expandable particles was immediately weighed, and allowed to stand for 24 hours under an environment of temperature 23 ± 2 ° C. and humidity 50 ± 5%. After standing, the mass W2 (g) of the foamable particles was measured, and the amount of impregnated gas of the foamable particles was calculated by the following equation.
Amount of impregnated gas of expandable particles (mass%) = (W1−W2) / W1 × 100

<Bulk density of foamed particles>
The foamed particles were weighed at an arbitrary mass W (g) as a measurement sample. The measurement sample was allowed to fall naturally into a measuring cylinder, and then the bottom of the measuring 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 value and the minimum value of the diameter of the expanded particles were measured with a Mitutoyo Digimatic caliper, and the average particle size (mm) was calculated by the following equation. The average value of the average particle size of 10 randomly selected expanded particles was taken as the average particle size.
Average particle size (mm) = (maximum diameter + minimum diameter) / 2

<Average bubble diameter of foam particles>
The average cell diameter of the foamed particles was measured by the following method. Specifically, the foam particles are divided into two halves using a razor so that the center of the foam particles passes through, and the cut surface is divided into "S-3000N" manufactured by Hitachi, Ltd. or "S-3400N" manufactured by Hitachi High-Technologies Corporation. Photographed with a scanning electron microscope. The photographed image was printed on A4 paper, and the minimum diameter and the maximum diameter passing through the center of the foamed particles were subtracted. From the center, a circle with a radius of 7/10 was drawn based on the smallest diameter. The inside B of the drawn circle was taken as the area B as the center. Also, a circle with a radius of 7/10 was drawn from the center with respect to the largest diameter. The outside of the drawn circle was taken as the area A as the surface layer.
In the region B, an arbitrary straight line contacting with 20 or more bubbles was drawn, the length L of the straight line was measured, and the number N of bubbles touching the straight line was counted. If a straight line contacting 20 bubbles could not be drawn, the longest straight line was drawn in the region. Arbitrary straight lines should be connected only as far as possible, and included in the number of bubbles if they could. When the bubbles were small and difficult to count, they were enlarged and photographed and measured. From the measurement results, the average chord length t and the bubble diameter D were calculated by the following formulas, and the arithmetic mean of the bubble diameter D was taken as the average bubble diameter (central portion).
Average chord length t (μm) = line length L / (number of bubbles N × magnification of photograph)
Bubble diameter D (μm) = average chord length t / 0.616
It calculated similarly about the area | region A, and made these arithmetic mean the average bubble diameter (surface layer part).

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

<Density of Foamed Molding>
Immediately after molding, the foamed molded article was dried at a temperature of 40 ° C. for 12 hours, and after drying, conditioned for 72 hours under an environment of a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5%. The mass a (g) of the conditioned foam molded body is measured to two decimal places, and the outer dimension is measured to 1/100 mm with a Digimatic caliper (manufactured by Mitutoyo Co., Ltd.) to obtain an apparent volume b (cm ³ ) I asked. The density of the foam molded article was calculated by the following equation.
Density (g / cm ³ ) = a / b

<Asker C hardness of foam molding>
Asker C hardness is a “Asker rubber plastic hardness tester manufactured by Kobunshi Keiki Co., Ltd.” after conditioning a test piece having a smooth surface with a thickness of 10 mm or more for 72 hours or more under an environment of temperature 23 ± 2 ° C. and humidity 50 ± 5%. It was measured using a "C" hardness tester. The pressure surface was brought into close contact so that the needle was perpendicular to the smooth measurement surface of the test piece, and the scale was read immediately. The fused surface of the foam particles was not used, and 5 points of the sample were measured, and the average value of these was taken as Asker C hardness.

<Resilience modulus of foam molding>
It measured based on JIS K 6400-3: 2011. A sample cut from the same foam that has been conditioned for at least 72 hours in an environment of temperature 23 ± 2 ° C. and humidity 50 ± 5% on a “FR-2” rebound resilience tester manufactured by Kobunshi Keiki Co. 40 mm or more in thickness Set so as to be stacked, and let the copper ball (φ 5/8 inch, 16.3 g) fall freely from the height (a) of 500 mm, and read the height (b) when the repulsion maximum reached, formula The rebound resilience (%) was calculated by (b) / (a) × 100. However, measurement was performed 3 times using the same test piece, and these average values were made into the impact resilience modulus.

<Glossiness of Foamed Molding>
When the foamed molded product was inclined 45 ° under a fluorescent lamp, when the glossiness could be confirmed visually, it was evaluated as ○, and when it could not be confirmed, it was evaluated as x.

Example 1
(1) Resin particles Ester based elastomer (trade name: "Pelprene GP-475", manufactured by Toyobo Co., Ltd., hard segment: polybutylene terephthalate and polybutylene isophthalate, soft segment: aliphatic polyether) 100 parts by mass and organic foam 0.3 parts by mass of a modifier (ethylenebisstearic acid amide, trade name: "Kao wax EBFF", manufactured by Kao Corporation) was supplied to a single-screw extruder, and melt-kneaded at 180 to 280 ° C. Next, the molten ester elastomer is cooled to adjust its viscosity, and then the resin is taken from each nozzle of a multi-nozzle die (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 to 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 Into an autoclave with a stirrer having a volume of 5 L, 1.5 kg (100 parts by mass) of resin particles, 3 L of distilled water, surfactant (sodium linear alkyl benzene sulfonate, trade name: "Neurex R" Then, 4 g of Yuka Sangyo Co., Ltd. was charged and sealed, and 16 parts by mass of butane (normal butane: isobutane = 7: 3) as a foaming agent was injected under stirring. The autoclave was then heated to 70 ° C. for 2 hours and cooled to 25 ° C. After cooling was completed, the autoclave was depressurized, and the surfactant was immediately washed with distilled water and dehydrated to obtain foamable particles. The amount of impregnation gas of the foamable particles was 6.6% by mass.

(3) Foamed particles 1.5 kg (100 parts by mass) of the expandable particles 0.25 parts by mass of an anti-cohesion agent (polyoxyethylene polyoxypropylene glycol, trade name: "Epan 450", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) The solution was applied to a cylindrical prefoamer equipped with a stirrer and having an inner volume of 50 L, and heated with steam having a gauge pressure of 0.12 MPa while stirring to obtain foam particles.
(4) Foam Molded Body Foamed particles were charged into an autoclave, and after introducing nitrogen gas with a gauge pressure of 0.3 MPa, the foam particles were allowed to stand at 30 ° C. for 18 hours to impregnate the foam particles with nitrogen gas (internal pressure applied). The impregnated amount of nitrogen gas was 0.9% by mass.
The foamed particles were taken out of the autoclave and immediately filled in a molding cavity having a size of 400 mm × 300 mm × 20 mm thick having water vapor holes, and heat molded with water vapor having a gauge pressure of 0.21 MPa to obtain a foam molded article .

Example 2
(1) Foamable particles 1.5 kg (100 parts by mass) of resin particles prepared in Example 1, 3 liters of distilled water, surfactant (sodium linear alkyl benzene sulfonate, trade name) in an agitator with an internal volume of 5 liters 4 g of “Neurex R” (manufactured by Yuka Sangyo Co., Ltd.) is charged, and after sealing, 16 parts by mass of butane (normal butane: isobutane = 7: 3) as a foaming agent under stirring condition and pentane (normal pentane: isopentane = 8: 2) 1 part by mass was pressed in. The autoclave was then heated to 70 ° C. for 2 hours and cooled to 25 ° C. After cooling was completed, the autoclave was depressurized, and the surfactant was immediately washed with distilled water and dehydrated to obtain foamable particles. The amount of impregnation gas of the foamable particles was 6.5% by mass.
(2) Expanded Particles Expanded 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. In addition, the nitrogen gas impregnation amount of the foaming particle by internal pressure provision was 0.8 mass%.

Example 3
(1) Expandable Particles Expandable particles were obtained in the same manner as in Example 1 except that the heating temperature of the autoclave was changed to 100 ° C. using the resin particles produced in Example 1. In addition, the amount of impregnation gas of the foamable particles was 6.7% by mass.
(2) Foamed particles 1.5 kg (100 parts by mass) of the expandable particles 0.25 parts by mass of an antibonding agent (polyoxyethylene polyoxypropylene glycol, trade name: "Epan 450", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) The solution is charged into a cylindrical prefoamer with an internal volume of 50 L at 20 minutes after extraction from the autoclave, heated with steam at a gauge pressure of 0.14 MPa while stirring, and then foamed particles are obtained. I got
(3) Foam Molded Product A foam molded product was obtained in the same manner as in Example 1. In addition, the nitrogen gas impregnation amount of the foaming particle by internal pressure provision was 0.8 mass%.

Comparative Example 1
(1) Foamable particles 1.5 kg (100 parts by mass) of resin particles prepared in Example 1, 3 liters of distilled water, surfactant (sodium linear alkyl benzene sulfonate, trade name) in an agitator with an internal volume of 5 liters 4 g of “Neurex R” (manufactured by Yuka Sangyo Co., Ltd.) was charged, and after sealing, 16 parts by mass of butane (normal butane: isobutane = 7: 3) as a foaming agent was injected under stirring. The autoclave was then heated to 100 ° C. for 2 hours and cooled to 25 ° C. After cooling was completed, the autoclave was depressurized, and the surfactant was immediately washed with distilled water and dehydrated to obtain foamable particles. The amount of impregnation gas of the foamable particles was 7.2% by mass.
(2) Expanded Particles Expanded 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. In addition, the nitrogen gas impregnation amount of the foaming particle by internal pressure provision was 0.9 mass%.
Various physical property values of Examples 1 to 3 and Comparative Example 1 are summarized in Table 1. Moreover, the cross-sectional photograph of the foaming particle of Examples 1-3 and the comparative example 1 is shown to FIGS.

  It can be seen from Table 1 that the foam molded articles of Examples 1 to 3 have high gloss surfaces. It can be seen from FIGS. 1 to 4 that the foamed particles of Examples 1 to 3 have a large average cell diameter in the surface layer portion.

Claims (9)

High gloss foam particles composed of a resin composition containing an ester elastomer as a base resin,
The high gloss foam particles have a plurality of cells satisfying the relationship of A> B (A is an average cell diameter of the surface layer portion and B is an average cell diameter of a center portion),
High gloss foam particles characterized in that the average cell diameter of the surface layer portion is 80 to 400 μm, and the average cell diameter of the central portion is 10 to 200 μm.   The high gloss foam particles according to claim 1 or 2, wherein the A and B satisfy the relationship of A / B> 1.5. The resin composition has (i) a storage elastic modulus by solid viscoelasticity measurement at a Vicat softening temperature Tv−10 ° C. of 1 × 10 ⁷ to 2 × 10 ⁸ Pa, and (ii) 1 × 10 ⁶ to 2 × 10 ⁷ The high-gloss expanded particles according to any one of claims 1 or 2, which have at least one physical property of storage elastic modulus by melt viscoelasticity measurement at a crystallization temperature Tc of Pa. The high gloss foam particles are
(I) The bulk density according to any one of claims 1 to 3 having at least one physical property of an average particle diameter of a bulk density of 0.02 to 0.4 g / cm ³ (ii) 1.5 to 15 mm. Glossy foam particles. It is a method of manufacturing the high gloss foaming particles according to any one of claims 1 to 4,
A method of producing high-gloss foam particles, comprising the steps of: impregnating a resin particle containing the ester elastomer as a base resin with a foaming agent to obtain foamable particles; and foaming the foamable particles. .   A foam molded article obtained by in-mold foaming of the high gloss foam particles according to any one of claims 1 to 5. The foam molded body is
(I) A density of 0.02 to 0.4 g / cm ³ (ii) Repulsion modulus of 50 to 100% (iii) An Asker C hardness of 20 to 65 according to claim 6 at least having physical properties Foam molded body.   The foam molded article according to claim 6 or 7, wherein the foam molded article is used as a construction material, a shoe member, a sporting goods, a shock absorbing material, a seat cushion or an automobile member. A method of producing the foam molded article according to any one of claims 6 to 8, wherein
Production of a foam molded article comprising the step of in-mold foaming of the high-gloss foam particles according to any one of claims 1 to 4 using a steam having a gauge pressure of 0.05 to 0.4 MPa as a heating medium Method.