JP6366535B2 - Amide-based elastomer expanded particles, method for producing the same, and expanded molded article - Google Patents

Description

  The present invention relates to an amide-based elastomer expanded particle, a method for producing the same, and an expanded molded body. More specifically, the present invention relates to an amide-based elastomeric foamed particle capable of providing a foamed molded product having good surface elongation and good fusion between the foamed particles when producing the foamed molded product, a method for producing the same, and an amide-based product The present invention relates to a foam molded article obtained from elastomer foam particles. The foamed molded product of the present invention can be used in industrial fields, sports equipment, cushioning materials, seat cushions, automobile members, and the like. In particular, it can be used for applications that require improved recovery.

  Conventionally, polystyrene foam moldings are widely used as cushioning materials and packing materials. Here, the foamed molded body is obtained by heating foamed particles such as expandable polystyrene particles and foaming (pre-foaming) to obtain foamed particles (pre-foamed particles). After being filled in, it can be obtained by secondary foaming and integrating the foamed particles by heat fusion.

A polystyrene foam molded article is known to have low recovery and rebound, although the raw material monomer is styrene and has high rigidity. Therefore, there has been a problem that it is difficult to use in applications where repeated compression or flexibility is required.
In order to solve the above-mentioned problem, Patent Document 1 includes about 13 to 27 times using foamed particles made of a crosslinked product of a thermoplastic elastomer resin made of a block copolymer having a crystalline polyamide segment and a polyether segment. Magnification foam moldings have been proposed. This foamed molded product is said to exhibit a high degree of rubber elasticity.

Japanese Patent Publication No. 4-17977

  However, the foamed particles of Patent Document 1 are also crosslinked on the surface thereof. For this reason, there has been a problem that the degree of freedom in shape becomes low due to the elongation of the surface during molding and the lack of fusion between particles.

Therefore, the inventors of the present invention, as a result of earnest investigation, as a base resin, in addition to the non-crosslinked amide elastomer, by using a modified polyolefin, the elongation of the surface when producing a foam molded article, The present inventors have found that expanded particles having improved fusibility between expanded particles can be provided.
Thus, according to the present invention, there is provided an amide elastomer foamed particle characterized in that it is a foamed particle comprising 100 parts by mass of a non-crosslinked amide elastomer and 1 to 30 parts by mass of a modified polyolefin as a base resin.

Further, according to the present invention, there is provided a method for producing the above amide elastomer expanded particle,
A step of impregnating a resin particle containing 100 parts by mass of a non-crosslinked amide-based elastomer, 1 to 30 parts by mass of a modified polyolefin and 0.02 to 1 part by mass of a cell regulator to obtain foamable particles; A method for producing expanded amide-based elastomer particles comprising the step of foaming functional particles.
Further, according to the present invention, there is provided a foam molded body obtained mold by foaming A bromide elastomer pre-expanded particles, an amide-based elastomer pre-expanded particles, and amide elastomer 100 parts by weight of non-crosslinked There is provided a foamed molded article, which is a pre-foamed particle containing 1 to 30 parts by mass of a modified polyolefin as a base resin .

According to the amide elastomer foamed particles of the present invention, it is possible to improve the surface elongation at the time of producing a foamed molded product and the fusion property between the foamed particles.
When the non-crosslinked amide elastomer is a copolymer having a polyamide block and a polyether block, and the modified polyolefin is selected from an olefin- (meth) acrylate ester-unsaturated carboxylic acid copolymer, a foam molded article It is possible to further improve the elongation of the surface and the fusibility between the foamed particles when producing the.
When the modified polyolefin is dispersed as fine particles in a photograph of 5000 times the cell wall cross section of the outermost layer of the amide elastomer foamed particles, and the fine particles are dispersed at 2 to 30 particles / μm ² , a foam molded article is produced. It is possible to further improve the elongation of the surface and the fusion property between the expanded particles.
When the amide elastomer foamed particles have an average cell diameter of 20 to 250 μm and an average particle diameter of 1.5 to 15 mm, the elongation of the surface at the time of producing the foamed molded product and the fusion property between the foamed particles Can be improved more.
In the method for producing amide elastomer expanded particles, when the cell regulator is a fatty acid amide organic material, the amide elastomer expanded particles can be more easily produced.

It is explanatory drawing of the imaging | photography method of the dispersion | distribution number of the microparticles | fine-particles of an Example, and a total area cross-section photograph. 2 is a cross-sectional photograph of expanded particles of Example 1. FIG. 2 is a cross-sectional photograph of expanded particles of Example 2. FIG. 2 is a cross-sectional photograph of expanded particles of Comparative Example 1.

Hereinafter, the present invention will be described in detail.
(Amide-based elastomer expanded particles)
The amide elastomer expanded particles (hereinafter also referred to as expanded particles) include a non-crosslinked amide elastomer and a modified polyolefin as a base resin. In the present specification, the term “non-crosslinked” means that the gel fraction insoluble in a soluble organic solvent is 3.0% by mass or less.
Here, the gel fraction of the expanded particles is measured in the following manner.
The mass W1 of the expanded particles is measured. Next, the amide elastomer foamed particles are immersed in 100 ml of a solvent at 130 ° C. (for example, 3-methoxy-3-methyl-1-butanol) for 24 hours.

Next, the residue in the solvent is filtered using an 80-mesh wire mesh, and the residue remaining on the wire mesh is dried at 150 ° C. for 1 hour. The mass W2 of the residue remaining on the wire mesh is measured, and the gel fraction of the expanded particles can be calculated based on the following formula.
Gel fraction (mass%) = 100 × W2 / W1

(1) Non-crosslinked amide-based elastomer As the non-crosslinked amide-based elastomer, a copolymer having a polyamide block (hard segment) and a polyether block (soft segment) can be used.

  Examples of the polyamide block include poly ε-capramide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexa Methylene dodecamide (nylon 612), polyundecane methylene adipamide (nylon 116), polyundecanamide (nylon 11), polylauramide (nylon 12), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthalamide ( Polyamide structures such as nylon 6T), polynanomethylene terephthalamide (nylon 9T), and polymetaxylylene adipamide (nylon MXD6). The polyamide block may be a combination of units constituting these polyamide structures.

Examples of the polyether block include polyether structures such as polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene glycol (PTMG, polytetrahydrofuran: PTHF). The polyether block may be a combination of units constituting these polyether structures.
The polyamide block and the polyether block may be dispersed randomly.

The number average molecular weight Mn of the polyamide block is preferably 300 to 15000, and more preferably 600 to 5000. The number average molecular weight Mn of the polyether block is preferably 100 to 6000, and more preferably 200 to 3000.
The non-crosslinked amide elastomer preferably has a Shore D hardness of 20 to 75, and more preferably 30 to 70. Shore D hardness is measured in accordance with JIS K6253-3: 2012.

The non-crosslinked amide elastomer preferably has a melting point of 120 to 180 ° C, more preferably 125 to 175 ° C. If the melting point is lower than 120 ° C, there is a risk of shrinkage when exposed to room temperature after foaming. If the melting point exceeds 180 ° C, foaming to a desired expansion ratio may be difficult.
The melting point of the non-crosslinked amide elastomer is measured with a differential thermal analyzer (DSC) according to JIS K7121: 1987. The melting point is the endothermic peak value temperature in the reheating process.

  Non-crosslinked amide elastomers include U.S. Pat.No. 4,331,786, U.S. Pat.No. 4,115,475, U.S. Pat.No. 4,195,015, U.S. Pat.No. 4,839,441, U.S. Pat.No. 4,864,014, U.S. Pat. Amide-based elastomers described in Japanese Patent No. 4,230,838 and US Pat. No. 4,332,920 can also be used.

The non-crosslinked amide elastomer is preferably obtained by copolycondensation of a polyamide block having a reactive end and a polyether block having a reactive end. Examples of this copolycondensation include the following:
1) Copolycondensation of polyamide block having diamine chain end and polyoxyalkylene block having dicarboxylic acid chain end 2) Cyanoethylation and hydrogenation of aliphatic dihydroxylated α, ω-polyoxyalkylene unit called polyether diol Copolycondensation of a polyamide unit having a dicarboxylic acid chain end and a polyoxyalkylene unit having a diamine chain end obtained by chemical conversion 3) Copolycondensation of a polyamide unit having a dicarboxylic acid chain end and a polyether diol (in this case) What is obtained is called polyetheresteramide)

Examples of the compound giving a polyamide block having a dicarboxylic acid chain end include a compound obtained by condensation of a dicarboxylic acid and a diamine in the presence of an α, ω-aminocarboxylic acid, lactam or dicarboxylic acid chain regulator. .
In the case of the copolycondensation of 1), the non-crosslinked amide elastomer reacts with, for example, polyether diol, lactam (or α, ω-amino acid), and chain limiter diacid in the presence of a small amount of water. Can be obtained. The non-crosslinked amide-based elastomer may have polyether blocks and polyamide blocks of various lengths, and may be dispersed in the polymer chain by causing each component to react randomly.

  In the copolycondensation, the polyether diol block may be used as it is, or may be used by copolymerizing the hydroxyl group and a polyamide block having a carboxy terminal group. The hydroxyl group is aminated to form a polyether diamine. After conversion, it may be condensed with a polyamide block having a carboxy end group. It is also possible to obtain a polymer including randomly dispersed polyamide blocks and polyether blocks by mixing polyether diol blocks with a polyamide precursor and a chain limiter and copolycondensation.

  As long as the base resin does not impair the effects of the present invention, in addition to non-crosslinked amide elastomers, other resins such as amide resins, polyether resins, crosslinked amide elastomers, styrene elastomers, and olefin elastomers may be used. It may be included. The other resin may be a known thermoplastic resin or thermosetting resin.

(2) Modified polyolefin Examples of the modified polyolefin include olefin- (meth) acrylic acid ester-unsaturated carboxylic acid copolymer and olefin- (meth) acrylic acid ester copolymer. Among these, an olefin- (meth) acrylic acid ester-unsaturated carboxylic acid copolymer is preferable from the viewpoint of further improving the fusibility.
Examples of the olefin include ethylene hydrocarbons having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 1-butene, 1-pentene and 1-hexene.
(Meth) acrylic acid esters include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid 2-ethylhexyl etc. are mentioned. Among these, methyl acrylate, methyl methacrylate, ethyl acrylate, and ethyl methacrylate are preferable.

Unsaturated carboxylic acids include their anhydrides. Specifically, in addition to acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid and the like, half esters and half amides of unsaturated dicarboxylic acids (eg maleic acid) Etc. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and maleic anhydride is particularly preferable.
Moreover, the form in the copolymer of the unit derived from an olefin, (meth) acrylic acid ester, and unsaturated carboxylic acid is not limited, For example, it exists in forms, such as random copolymerization, block copolymerization, and graft copolymerization. obtain.
As the olefin- (meth) acrylic acid ester-unsaturated carboxylic acid copolymer, it is most preferable to use an ethylene-acrylic acid ester-maleic anhydride copolymer. Examples of the acrylate ester include methyl acrylate and ethyl acrylate, and ethyl acrylate is particularly preferable.

In the olefin- (meth) acrylic acid ester-unsaturated carboxylic acid copolymer, the (meth) acrylic acid ester content is preferably 0.1 to 30% by mass, and more preferably 1 to 30% by mass. 3 to 30% by mass is more preferable. The unsaturated carboxylic acid content is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, still more preferably 0.5 to 10% by mass. It is particularly preferably 10 to 10% by mass, and particularly preferably 1 to 5% by mass.
The modified polyolefin preferably has a melt flow rate (MFR) of 0.5 to 200 g / 10 minutes, more preferably 1 to 50 g / 10 minutes. MFR is measured according to JIS K 7210: 1999.
The compounding quantity of modified polyolefin is 1-30 mass parts with respect to 100 mass parts of amide-type elastomers. When the amount of the modified polyolefin is less than 1 part by mass, the effect of improving the fusion may not be seen. When the amount is more than 30 parts by mass, the hardness of the foamed molded product is lowered, which may hinder the characteristics of the amide elastomer or increase the cost. The blending amount is preferably 3 to 25 parts by mass, and more preferably 5 to 20 parts by mass.

(3) Shape of Expanded Particle, etc. The shape of the expanded particle is not particularly limited, and examples thereof include true spherical shape, elliptical spherical shape (egg shape), cylindrical shape, prismatic shape, pellet shape, granular shape, and the like.
The modified polyolefin is preferably dispersed as fine particles in a photograph of 5000 times the cell wall cross section of the outermost layer of the amide elastomer expanded particles. The inventors consider that the fine particles of the modified modified polyolefin contribute to the improvement of the fusion property at the time of foam molding. Here, the fine particles are preferably dispersed at ² to 30 particles / μm ² . When the number of dispersion is less than 2, the effect of improving fusion may not be obtained. When the number is more than 30, the proportion of the modified polyolefin may increase and the surface hardness may decrease. A more preferable dispersion number is 5 to 20.
The expanded particles have an average cell diameter of 20 to 250 μm. When the average cell diameter is less than 20 μm, the foamed molded product may shrink. When larger than 250 micrometers, the deterioration of the external appearance of a molded object and the defect of a fusion | melting may be caused. A more preferable average cell diameter is 20 to 200 μm.

  The expanded particles preferably have an average particle diameter of 1.5 to 15 mm. When the average particle diameter is less than 1.5 mm, it is difficult to produce foamed particles, and the production cost may increase. When it is larger than 15 mm, it may be difficult to obtain a foamed molded product having a complicated shape when producing the foamed molded product by in-mold molding. A more preferable average particle diameter is 2.0 to 12 mm.

The expanded particles preferably have a bulk density in the range of 0.02 to 0.2 g / cm ³ . When the bulk density is less than 0.02 g / cm ³ , shrinkage may occur in the obtained foam molded article, the appearance may not be good, and the mechanical strength of the foam molded article may be reduced. When it is larger than 0.2 g / cm ³ , the lightweight property of the foamed molded product may be lowered. A more preferable bulk density is 0.05 to 0.1 g / cm ³ .
The foamed particles can be used as they are in the cushioning filler, or can be used as a raw material for a foamed molded product for foaming in the mold. When used as a raw material for a foamed molded article, the expanded particles are generally referred to as “pre-expanded particles”, and the foam for obtaining them is referred to as “pre-expanded”.

(Method for producing amide-based elastomer expanded particles)
The amide elastomer foamed particles are obtained by impregnating a foaming agent into resin particles containing 100 parts by mass of a non-crosslinked amide elastomer, 1 to 30 parts by mass of a modified polyolefin, and 0.02 to 1 part by mass of a cell regulator. Can be obtained through a step of obtaining (impregnation step) and a step of foaming the expanded particles (foaming step).

(1) Impregnation step The resin particles impregnated with the foaming agent contain 100 parts by mass of a non-crosslinked amide elastomer, 1 to 30 parts by mass of a modified polyolefin, and 0.02 to 1 part by mass of a cell regulator.
(A) Bubble regulators Examples of the bubble regulator include higher fatty acid amides, higher fatty acid bisamides, higher fatty acid salts, and inorganic cell nucleating agents. These bubble regulators may be used in combination.
Examples of higher fatty acid amides include stearic acid amide and 12-hydroxystearic acid amide.
Examples of higher fatty acid bisamides include ethylene bis stearamide, ethylene bis-12-hydroxy stearamide, and methylene bis stearamide.
An example of the higher fatty acid salt is calcium stearate.
Examples of inorganic cell nucleating agents include talc, calcium silicate, synthetic or naturally produced silicon dioxide, and the like.

Of the above-mentioned bubble regulators, higher fatty acid amides and higher fatty acid bisamide fatty acid amide organic substances are preferred.
The amount of the bubble regulator is 0.02 to 0.3 parts by mass with respect to 100 parts by mass of the non-crosslinked amide elastomer. When the amount of the bubble adjusting agent is less than 0.02 parts by mass, the effect of refining bubbles by the bubble adjusting agent may be reduced. This decrease roughens the bubbles of the foamed particles obtained by foaming the foamable particles, and as a result, the foamed particles can be foamed and shrunk during in-mold foam molding to obtain a foamed molded product, Even if a foamed molded product is obtained, it leads to a decrease in appearance such as unevenness on the surface. When the amount is more than 0.3 parts by mass, the effect reaches a peak, and problems such as insufficient fusion of the foamed molded product and cost increase may occur. The amount of the bubble regulator is preferably 0.05 to 0.1 parts by mass.

(B) Resin particles The resin particles can be obtained using a known production method and production equipment.
For example, resin particles can be produced by melt-kneading a non-crosslinked amide elastomer resin using an extruder and granulating by extrusion, underwater cutting, strand cutting, or the like. The temperature, time, pressure, etc. at the time of melt-kneading can be appropriately set according to the raw materials used and the production equipment.
The melt kneading temperature in the extruder at the time of melt kneading is preferably 170 to 250 ° C, more preferably 200 to 230 ° C, which is a temperature at which the non-crosslinked amide elastomer is sufficiently softened. The melt-kneading temperature means the temperature of the melt-kneaded material inside the extruder as measured at the center temperature of the melt-kneaded material flow path near the extruder head with a thermocouple thermometer.

The shape of the resin particles is, for example, a true sphere, an elliptical sphere (egg), a columnar shape, a prismatic shape, a pellet shape, or a granular shape.
The resin particles preferably have an L / D of 0.8 to 3 when the length is L and the average diameter is D. When the L / D of the resin particles is less than 0.8 or exceeds 3, the filling ability into the mold may be lowered. The length L of the resin particles refers to the length in the extrusion direction, and the average diameter D refers to the diameter of the cut surface of the resin particles substantially perpendicular to the direction of the length L.
The average diameter D of the resin particles is preferably 0.5 to 3 mm. When the average diameter is less than 0.5 mm, the retention of the foaming agent may be lowered, and the foamability of the foamable particles may be lowered. When the thickness is larger than 3 mm, the filling property of the foamed particles in the molding die is lowered, and the thickness of the foamed molded product may not be reduced when producing a plate-like foamed molded product.
The cell regulator may be mixed with the resin in the extruder or may be adhered to the resin particles.
In addition, the resin particles may contain a flame retardant such as hexabromocyclododecane and triallyl isocyanurate hexabromide, and a colorant such as carbon black, iron oxide, and graphite.

(C) Expandable particles Expandable particles are produced by impregnating resin particles with a foaming agent. As a procedure for impregnating the resin particles with the foaming agent, a known procedure can be used. For example, by supplying resin particles, a dispersing agent and water in an autoclave and stirring, the resin particles are dispersed in water to produce a dispersion, and a foaming agent is press-fitted into the dispersion. And a method of impregnating with a foaming agent.
The dispersant is not particularly limited, and examples thereof include poorly water-soluble inorganic substances such as calcium phosphate, magnesium pyrophosphate, sodium pyrophosphate, and magnesium oxide, and surfactants such as sodium dodecylbenzenesulfonate.

As the blowing agent, general-purpose ones are used, and examples thereof include inorganic gases such as air, nitrogen and carbon dioxide (carbon dioxide); aliphatic hydrocarbons such as propane, butane and pentane; halogenated hydrocarbons, Group hydrocarbons are preferred. In addition, a foaming agent may be used independently and may use 2 or more types together.
If the amount of the foaming agent impregnated into the resin particles is small, the foamable particles may not be foamed. If the amount is too large, the resin particles may break during foaming due to the plasticizing effect of the foaming agent. The amount of the foaming agent is preferably 5 parts by mass or more, more preferably 5 to 30 parts by mass, and further preferably 10 to 20 parts by mass with respect to 100 parts by mass of the resin particles. preferable.

The content (impregnation amount) of the foaming agent impregnated with respect to 100 parts by mass of the resin particles is measured as follows.
About 15 mg of resin particles are accurately weighed and set at the cracking furnace entrance of a pyrolysis furnace PYR-1A manufactured by Shimadzu Corporation, and purged with nitrogen for about 15 seconds to discharge the mixed gas at the time of sample setting. After sealing, the sample was inserted into a 200 ° C. core, heated for 120 seconds to release the gas, and the released gas was quantified using a gas chromatograph GC-14B (detector: FID) manufactured by Shimadzu Corp. Get quantity. The measurement conditions were as follows. The column used was Shimalite 60/80 NAW (Squalane 25%) 3 m × 3φ, column temperature (70 ° C.), carrier gas (nitrogen), carrier gas flow rate (50 ml / min), inlet temperature (110 ° C.) And the detector temperature (110 ° C.).

  If the impregnation temperature of the foaming agent into the resin particles is low, the time required for impregnating the foaming agent into the resin particles becomes long and the production efficiency may be lowered. On the other hand, when the particle size is high, the resin particles may be fused to generate a bond particle. The impregnation temperature is preferably 60 to 120 ° C, more preferably 70 to 110 ° C. A foaming aid (plasticizer) may be used in combination with the foaming agent. Examples of the foaming aid (plasticizer) include diisobutyl adipate, toluene, cyclohexane, and ethylbenzene.

(2) Foaming step In the foaming step, the foaming temperature and the heating medium are not particularly limited as long as foamable particles can be foamed to obtain foamed particles.
In the foaming step, it is preferable to add an inorganic component to the foamable particles. Examples of the inorganic component include inorganic compound particles such as calcium carbonate and aluminum hydroxide. The amount of the inorganic component added is preferably 0.03 parts by mass or more, more preferably 0.05 parts by mass or more, preferably 0.2 parts by mass or less, more preferably 0.1 parts by mass with respect to 100 parts by mass of the expandable particles. It is below mass parts.
When foaming is performed under high-pressure steam, if an organic anti-fusing agent is used, it may melt during foaming. On the other hand, an inorganic anti-fusing agent such as calcium carbonate has a sufficient anti-fusing effect even under high-pressure steam heating.
The particle diameter of the inorganic component is preferably 5 μm or less. The minimum value of the particle size of the inorganic component is about 0.01 μm. When the particle diameter of the inorganic component is not more than the upper limit, the amount of the inorganic component added can be reduced, and the inorganic component is less likely to adversely affect (inhibit) the subsequent molding process.

  In addition, you may apply | coat powdery metal soaps, such as zinc stearate, calcium carbonate, and aluminum hydroxide to the surface of a resin particle before foaming. By this application, the bonding between the resin particles in the foaming process can be reduced. Moreover, you may apply | coat surface treatment agents, such as an antistatic agent and a spreading agent. Examples of the antistatic agent include polyoxyethylene alkylphenol ether and stearic acid monoglyceride. Examples of the spreading agent include polybutene, polyethylene glycol, and silicone oil.

(Foamed molded product)
The foamed molded body is obtained by molding foamed particles in a mold, and is composed of a fusion product of a plurality of foamed particles. For example, the foamed particles are filled in a closed mold having a large number of small holes, the foamed particles are heated and foamed with pressurized steam, and the voids between the foamed particles are filled, and the foamed particles are fused and integrated with each other. Can be obtained. 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.

The foamed molded product preferably has a density of 0.05 to 0.1 g / cm ³ . If it is this range, both recoverability and mechanical properties can be achieved in a good balance.
Furthermore, the foaming particles may be impregnated with an inert gas to improve the foaming power of the foamed particles. By improving the foaming force, the fusibility between the foamed particles is improved at the time of in-mold molding, and the foamed molded article has further excellent mechanical strength. In addition, as an inert gas, a carbon dioxide, nitrogen, helium, argon etc. are mentioned, for example.

  Examples of the method of impregnating the expanded particles with the inert gas include a method of impregnating the expanded particles with the inert gas by placing the expanded particles in an inert gas atmosphere having a pressure equal to or higher than normal pressure. The foamed particles may be impregnated with an inert gas before filling into the mold, but may be impregnated by placing the foamed particles in the mold in an inert gas atmosphere after filling the mold into the mold. . When the inert gas is nitrogen, it is preferable to leave the expanded particles in a nitrogen atmosphere of 0.1 to 2.0 MPa for 20 minutes to 24 hours.

  When the foam particles are impregnated with an inert gas, the foam particles may be heated and foamed in the mold as they are. It is also possible to form expanded particles with a magnification, fill the mold, and heat and foam. By using such expanded particles with a high expansion ratio, a foamed molded article with a high expansion ratio can be obtained.

Further, when an anti-fusing agent is used during the production of the foamed particles, the anti-fusing agent may be molded while adhering to the foamed particles during the production of the foamed molded article. In addition, in order to promote the mutual fusion of the foam particles, the anti-fusing agent may be washed and removed before the molding process, and stearic acid is added as a fusion accelerator during molding without removing it. May be.
The foamed molded product of the present invention can be used, for example, in the industrial field, sports equipment, cushioning material, seat cushion, automobile member, and the like. In particular, it can be used for applications that require improved recovery.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
<Bulk density of expanded particles>
First, Wg was collected as a measurement sample of foamed particles, and this measurement sample was naturally dropped into a graduated cylinder, and then lightly shaken to make the apparent volume (V) cm ³ of the sample constant, and its mass and volume were measured. The bulk density of the expanded particles is measured based on the following formula.
Bulk density (g / cm ³ ) = mass of measurement sample (W) / volume of measurement sample (V)
Further, the bulk multiple of the expanded particles is a numerical value calculated by the following equation.
Bulk multiple (times) = 1 / bulk density (g / cm ³ )

<Average particle diameter of expanded particles>
About 50 g of the expanded particles were sieved using a low-tap type sieve shaker (manufactured by Terraoka Co., Ltd.) 5.60 mm, 4.75 mm, 4.00 mm, 3.35 mm, 2.80 mm, 2.36 mm, 2.00 mm. Classification for 5 minutes with JIS standard sieves of 1.70 mm, 1.40 mm, and 1.18 mm. The sample mass on the sieve mesh is measured, and based on the cumulative mass distribution curve obtained from the result, the particle diameter (median diameter) at which the cumulative mass is 50% is defined as the average particle diameter.

<Average bubble diameter>
The average cell diameter of the expanded particles refers to that measured in accordance with the test method of ASTM D2842-69. Specifically, the expanded particles are cut so as to be approximately bisected in the direction perpendicular to the extrusion direction, and the cut surface is used with a scanning electron microscope (trade name “S-3000N” manufactured by Hitachi, Ltd.). The photographed image is printed on A4 paper, and a straight line having a length of 60 mm is drawn at an arbitrary position, and the average chord length (t of bubbles) is calculated from the number of bubbles existing on the straight line. ) Is calculated from the following formula.
Average string length t = 60 / (number of bubbles × photo magnification)
When drawing a straight line, if the straight line is in point contact with the bubble, this bubble is included in the number of bubbles, and both ends of the straight line are not penetrating the bubble and are in the bubble. In this case, the bubbles in which both ends of the straight line are positioned are included in the number of bubbles. Furthermore, the average chord length is calculated in the same manner as described above at any five locations in the photographed image, and the arithmetic mean value of these average chord lengths is taken as the average bubble diameter of the foamed particles.

<Dispersed number and total area of fine particles>
A cross-sectional photograph of the expanded particles is taken under the following conditions, and the number of dispersed particles and the total area are calculated from the obtained photographs under the following conditions.
(1) Photographing Sectional photographs at a magnification of 5000 times in Examples and Comparative Examples are photographed under the following conditions.
(Example)
As shown in FIG. 1, a slice sliced across the B surface is cut out from the surface portion of the expanded particle 1 so that a plane parallel to the extrusion direction 2 (A surface in the figure) can be observed, and the slice is cut into an epoxy resin. After embedding, the epoxy resin is cured for 24 hours at a temperature of 60 ° C., and an ultrathin section (thickness 70 nm) is prepared using an ultramicrotome (“LEICA ULTRACUT UCT” manufactured by Leica Microsystems). The ultrathin section is photographed with a transmission electron microscope (“H-7600” manufactured by Hitachi High-Technologies Corporation, camera system “ER-B” manufactured by AMT Co.) Ruthenium tetroxide is used as a staining agent.
(Comparative example)
Photographs are taken in the same manner as in the Examples except that osmium tetroxide and ruthenium tetroxide are used as the staining agents.

(2) Calculation of the number of dispersions and the total area The method for measuring the number of dispersions is to calculate the area (cm ² ) using a cross-sectional photograph of 5000 times the magnification of the transmission electron microscope of the surface layer portion. The area is converted into an actual area (μm ² ). Next, count the number of particles in the photo. At this time, the total number of black portions and white portions is taken as the total number. The number per 1 μm ² is calculated from the total number and the actual size area. Further, the number of variances is calculated in the same manner as described above at any five locations in the photographed image, and the arithmetic average value is set as the number of variances.

<Appearance of foam molding>
The appearance of the foamed molded product was visually evaluated. The case where the boundary part where the foamed particles on the surface of the foamed molded product are joined is smooth is marked with ◯, and the case where the coalescence of bubbles occurs and the foamed particles and the foamed molded product cannot be obtained is marked with x.

<Heat fusion rate>
On the surface of a rectangular parallelepiped foam molded body of length 300 mm × width 400 mm × height 10 mm, a cutting line having a length of 300 mm and a depth of 2 mm is put in a horizontal direction with a cutter, and two foam molded bodies are formed along the cutting line. To divide. And, on the split surface of the foam molded article, the number of foam particles broken in the secondary foam particles (a) and the number of foam particles broken at the interface between the secondary foam particles (b) are measured, The thermal fusion rate was calculated based on the following formula. The thermal fusion rate is preferably 40% or more, and more preferably 50% or more.
Thermal fusion rate (%) = 100 × (a) / [(a) + (b)]

(Production example of amide elastomer resin particles)
First, 100 parts by mass of non-crosslinked (crystalline) amide elastomer (trade name “Pebax 5533”, manufactured by Arkema Inc., gel fraction of 3% by mass or less) using nylon 12 as a hard segment and polyether as a soft segment 5 parts by mass of polyolefin (trade name “BONDINE AX8390”, ethylene-ethyl acrylate (29 mass%)-maleic anhydride (1.3 mass%) copolymer, MFR: 7 g / 10 min, manufactured by Arkema) Was supplied to a 65 mm single screw extruder and melt kneaded. In the single screw extruder, the amide elastomer was first melt kneaded at 150 ° C. and then melt kneaded while raising the temperature to 200 ° C.
Subsequently, after the molten amide elastomer was cooled, the amide elastomer was extruded from each nozzle of a multi-nozzle mold attached to the front end of the single screw extruder. In addition, the multi-nozzle mold has 20 nozzles having a diameter of 1.0 mm at the outlet portion, and all the outlet portions of the nozzle have a diameter of 139.5 mm, assumed on the front end surface of the multi-nozzle die. It was arranged on the virtual circle at regular intervals. The multi-nozzle mold was held at 200 ° C.

Four rotating blades are integrally provided at equal intervals in the circumferential direction of the rotating shaft on the outer peripheral surface of the rear end portion of the rotating shaft, and each rotating blade is always attached to the front end surface of the multi-nozzle mold. It was configured to move on a virtual circle in contact.
Further, the cooling member includes a cooling drum including a front circular front portion and a cylindrical peripheral wall portion extending rearward from the outer peripheral edge of the front portion and having an inner diameter of 315 mm. The cooling water is supplied into the cooling drum through the supply pipe and the supply port of the drum, and the cooling water at 20 ° C. flows spirally forward along the inner surface of the inner surface of the peripheral wall portion. It was.
The rotary blade disposed on the front end surface of the multi-nozzle mold is rotated at a rotational speed of 3000 rpm, and the amide elastomer extrudate extruded from the outlet of each nozzle of the multi-nozzle mold is cut by the rotary blade. Thus, substantially spherical amide-based elastomer resin particles were produced.

In manufacturing the resin particles, first, the rotating shaft was not attached to the multi-nozzle mold, and the cooling member was retracted from the multi-nozzle mold. In this state, the amide elastomer was extruded from the extruder. Next, after attaching a rotating shaft to the multi-nozzle mold and disposing the cooling member at a predetermined position, the rotating shaft is rotated, and the amide elastomer is cut with a rotating blade at the opening end of the outlet portion of the nozzle to form resin particles. Manufactured.
The resin particles were blown outward or forward by the cutting stress of the rotary blade, and immediately cooled by colliding with the cooling water flowing along the inner surface of the cooling drum of the cooling member.
The cooled resin particles were discharged together with the cooling water through the outlet of the cooling drum, and then separated from the cooling water by a dehydrator. The obtained resin particles had a particle length L of 1.2 to 1.7 mm and a particle diameter D of 1.3 to 1.6 mm.

Example 1
<Production of expandable particles>
In an autoclave with a stirrer having an internal volume of 5 liters, 2.0 kg of the resin particles, 1.5 kg of distilled water, 5.2 g of magnesium pyrophosphate, and 0.70 g of sodium dodecylbenzenesulfonate were placed and suspended under stirring at 320 rpm.
Next, 0.5 kg of distilled water, 0.8 g of magnesium pyrophosphate, 0.1 g of sodium dodecylbezenesulfonate, and 2.0 g of ethylenebisstearic acid amide as a foam regulator (0.1 parts by mass with respect to 100 parts by mass of resin particles) ) And stirred with a homomixer to prepare a suspension, and this suspension was added to the reactor. Thereafter, the temperature was raised to 110 ° C., 410 g of butane (isobutane: normal butane = 35: 65 (mass ratio)) as a blowing agent was injected and held at 110 ° C. for 6 hours, and then cooled to 20 ° C. and taken out. Washing, dehydration and drying yielded expandable particles. With respect to 100 parts by mass of the obtained expandable particles, 0.1 parts by mass of calcium carbonate was uniformly coated on the entire surface of the expandable particles.

<Production of expanded particles>
The expandable particles were put into a cylindrical batch type pressure prefoaming machine having a volume of 50 liters and heated with steam to obtain expanded particles. The expanded particles had a bulk density of 0.1 g / cm ³ , an average bubble diameter of 41 μm, and an average particle diameter of 2.6 mm. Sectional photographs of the expanded particles are shown in FIGS. 2A is a surface layer portion, and FIGS. 2B and 2C are internal photographs. From these photographs, it can be seen that the modified polyolefin is dispersed as fine particles in the surface layer portion.

<Preparation of foam molded article>
The expanded particles were placed in a sealed container, and nitrogen was pressed into the sealed container at a pressure of 0.5 MPaG and left at room temperature for 12 hours to impregnate the expanded particles with nitrogen.
The foamed particles are taken out from the sealed container, filled into the cavity of a mold having a cavity of 400 mm × 300 mm × 10 mm, molded by heating with 0.25 MPa water vapor for 35 seconds, and a density of 0.1 g / cm 3. ³ foam molded articles were obtained. The obtained foamed molded article had a thermal fusion rate of 40% and had a fine and uniform cell structure.

(Example 2)
A foam molded article was obtained in the same manner as in Example 1 except that 10 parts by mass of the modified polyolefin was added. The obtained foamed molded article had a thermal fusion rate of 50% and had a fine and uniform cell structure. The bulk density of the expanded particles was 0.11 g / cm ³ , the average cell diameter was 31 μm, and the average particle diameter was 2.6 mm.
Cross-sectional photographs of the expanded particles are shown in FIGS. 3 (a) and 3 (b). 3A is a surface layer portion, and FIG. 3B is an internal photograph. From these photographs, it can be seen that the modified polyolefin is dispersed as fine particles in the surface layer portion.

(Example 3)
Except for using non-crosslinked (crystalline) amide elastomer (trade name “UBASTA9040”, manufactured by Ube Industries, gel fraction of 3% by mass or less) with nylon 12 as hard segment and polyether as soft segment A foamed molded product was obtained in the same manner as in Example 1. The obtained foamed molded article had a thermal fusion rate of 50% and had a fine and uniform cell structure. The bulk density of the expanded particles was 0.1 g / cm ³ , the average cell diameter was 44 μm, and the average particle size was 2.6 mm. Further, it was confirmed that the modified polyolefin was dispersed as fine particles in the surface layer portion in the foamed particles.

Example 4
In a production example of resin particles of amide elastomer, sodium bicarbonate citric acid chemical foaming agent (trade name “Finecell Master PO410K”, manufactured by Dainichi Seika Co., Ltd.) as a cell regulator for 100 parts by mass of amide elastomer. A foamed molded article was obtained in the same manner as in Example 1 except that 5 parts by mass were supplied. The obtained foamed molded article had a fine and uniform cell structure. The bulk density of the expanded particles was 0.1 g / cm ³ , the average cell diameter was 53 μm, and the average particle diameter was 2.6 mm. Further, it was confirmed that the modified polyolefin was dispersed as fine particles in the surface layer portion in the foamed particles.

(Comparative Example 1)
A foam molded article was obtained in the same manner as in Example 1 except that the modified polyolefin was not added. The obtained foamed molded article had a heat fusion rate of 30% and had a fine and uniform cell structure. The bulk density of the expanded particles was 0.1 g / cm ³ , the average cell diameter was 162 μm, and the average particle diameter was 2.6 mm.
Cross-sectional photographs of the expanded particles are shown in FIGS. 4 (a) and 4 (b). 4A is a surface layer portion, and FIG. 4B is an internal photograph. From these photographs, it can be seen that fine particles are not present in the surface layer portion.
Table 1 summarizes the physical properties of the examples and comparative examples. In the table, A means Pebax5533, B means UBASTA9040, C means BONDINEAX8390, and EBSA means ethylenebisstearic acid amide.

  From Table 1, it can be seen that a foamed molded article having good fusion property can be obtained from the foamed particles containing non-crosslinked amide elastomer and modified polyolefin as the base resin.

1 expanded particle, 2 extrusion direction, A surface parallel to extrusion direction, surface intersecting B A

Claims (7)

  An amide elastomer foamed particle comprising 100 parts by mass of a non-crosslinked amide elastomer and 1 to 30 parts by mass of a modified polyolefin as a base resin.   The non-crosslinked amide elastomer is a copolymer having a polyamide block and a polyether block, and the modified polyolefin is selected from an olefin- (meth) acrylic acid ester-unsaturated carboxylic acid copolymer. The amide-based elastomer expanded particles described. The modified polyolefin, in 5000 a magnification of the outermost layer of the cell wall cross-section of the amide elastomer foamed particles, and dispersed as fine particles, the fine particles 2 to 30 / claim are dispersed in [mu] m ² 1 or 2 2. The amide elastomer expanded particle according to 1.   The amide elastomer expanded particle according to any one of claims 1 to 3, wherein the expanded amide elastomer particle has an average cell diameter of 20 to 250 µm and an average particle diameter of 1.5 to 15 mm. It is a manufacturing method of amide system elastomer expanded particles given in any 1 paragraph of Claims 1-4,
A step of impregnating a resin particle containing 100 parts by mass of a non-crosslinked amide-based elastomer, 1 to 30 parts by mass of a modified polyolefin and 0.02 to 1 part by mass of a cell regulator to obtain foamable particles; A method for producing amide-based elastomer foamed particles comprising a step of foaming functional particles.   The method for producing expanded amide elastomer particles according to claim 5, wherein the air bubble adjusting agent is a fatty acid amide organic material. A foamed article obtained by in-mold by foaming A bromide elastomer pre-expanded particles, an amide-based elastomer pre-expanded particles, and amide elastomer 100 parts by weight of modified polyolefin 1 to 30 parts by weight of non-crosslinked A foamed molded article, which is a pre-foamed particle comprising a base resin .