JP2022057468A - Thermoplastic resin foamed particle, thermoplastic resin foamed particle molding, foamed resin composite body, method for producing thermoplastic resin foamed particle, and method for producing thermoplastic resin foamed particle molding - Google Patents

Abstract

To provide thermoplastic resin foamed particles which are excellent in a heat-resistant strength, in consideration of a softened foamed particle molding after a temperature has risen.SOLUTION: Thermoplastic resin foamed particles contain a thermoplastic resin, in which the thermoplastic resin contains a polyester-based resin and a polyimide-based resin, and a glass transition temperature is single. The glass transition temperature of the thermoplastic resin is preferably 80-130°C, and an absolute value in a difference between an endotherm and an exotherm determined by heat flux scanning differential calorimetry at a heating rate of 10°C/min is preferably 3-35 J/g.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a thermoplastic resin foamed particle, a thermoplastic resin foamed particle molded body, a foamed resin composite, a thermoplastic resin foamed particle, and a method for producing a thermoplastic resin foamed particle molded body.

The molded body (thermoplastic resin foamed particle molded body) of the foamed particles (thermoplastic resin foamed particles) containing the thermoplastic resin is lightweight and has excellent heat insulating properties, cushioning properties, and mechanical strength. Therefore, the application of the thermoplastic resin foamed particle molded product (sometimes referred to simply as “foamed particle molded product”) to automobiles, aircrafts, railroad vehicles, and the like is being studied.
Among the thermoplastic resins, polyester-based resins such as polyethylene terephthalate (PET) can be foamed particle molded bodies having excellent rigidity and heat resistance, and therefore, studies on foamed particle molded bodies using polysell-based resins are underway. ..

Examples of the method for producing a foamed particle molded product include in-mold foam molding. In-mold foam molding will be described. Thermoplastic foam particles (sometimes referred to simply as "foam particles") are filled into the mold cavity. The foamed particles in the cavity are heated by a heating medium such as hot water or steam to foam them into secondary foamed particles, and the secondary foamed particles are heat-fused and integrated by the foaming pressure of the foamed particles to form a desired shape. To obtain the foamed particle molded body of.

For example, in Patent Document 1, prefoamed particles of polyethylene terephthalate (PET) having a low degree of crystallization are filled in a mold, and the temperature of the mold surface is heated to a temperature higher than the glass transition temperature Tg of PET. Disclosed is a method for producing a foamed particle molded product, which is subjected to internal foam molding and then cooled over a predetermined time so that the surface temperature of the mold does not become lower than the glass transition temperature Tg. According to the invention of Patent Document 1, after the heating for in-mold foam molding is completed, the molded product is cooled without being taken out from the mold so that the surface temperature of the mold does not become lower than Tg. The crystallization of the molded product is promoted to improve the heating dimensional stability. However, the invention of Patent Document 1 has a problem that the molding time becomes long because a cooling step for promoting crystallization is required. The "heated dimensional stability" means a property that expansion or contraction is unlikely to occur when the temperature of the foamed particle molded product is increased.

To solve such a problem, Patent Document 2 proposes a method for producing foamed particles containing a crystalline polyester resin and an amorphous polyester resin having a specific glass transition temperature Tg in a specific ratio. .. According to the invention of Patent Document 2, since it contains an amorphous thermoplastic polyester resin having a glass transition temperature Tg higher than that of the crystalline polyester resin, the thermoplastic polyester resin foamed particles are used. The foamed particle molded body obtained by in-mold foam molding has excellent thermal dimensional stability without requiring a step for increasing the crystallinity.

International Publication No. 2000/03565 Japanese Unexamined Patent Publication No. 2014-070153

However, although the invention of Patent Document 2 is excellent in heat dimensional stability, it becomes soft when heated (heat resistance strength is low). Therefore, when the temperature rises, the rigidity may decrease.
Therefore, an object of the present invention is to provide thermoplastic resin foamed particles having excellent heat resistance.

As a result of diligent studies by the present inventors, the mixture of the crystalline polyester resin and the amorphous polyester resin is not sufficiently compatible with each other, so that the glass transition temperature of the lower of the two polyester resins is lower. It was found that when it reaches, it softens and deforms. Based on this finding, it was found that the heat resistance can be increased by including two kinds of highly compatible resins, and the present invention has been completed.

That is, the present invention has the following aspects.
<1>
Contains thermoplastic resin
The thermoplastic resin contains a polyester-based resin and a polyimide-based resin.
Thermoplastic resin foamed particles having a single glass transition temperature Tg.
<2>
The thermoplastic resin foamed particles according to <1>, wherein the glass transition temperature Tg is 80 to 130 ° C.
<3>
The thermoplastic resin foam according to <1> or <2>, wherein the absolute value of the difference between the heat absorption amount and the calorific value obtained by the heat flux differential scanning calorimetry at a heating rate of 10 ° C./min is 3 to 35 J / g. particle.
<4>
The content ratio of the polyester resin to the total mass of the thermoplastic resin is 40 to 95% by mass.
The content ratio of the polyimide resin to the total mass of the thermoplastic resin is 5 to 60% by mass.
The thermoplastic resin foamed particles according to any one of <1> to <3>.
<5>
The thermoplastic resin foaming according to any one of <1> to <4>, wherein the temperature at which the loss tangent tan δ is maximized in the solid viscoelasticity measurement at a heating rate of 5 ° C./min and a frequency of 1 Hz is 120 to 230 ° C. particle.
<6>
The thermoplastic resin foamed particles according to any one of <1> to <5>, wherein the polyimide-based resin is a polyetherimide-based resin.
<7>
The thermoplastic resin foamed particles according to any one of <1> to <6>, wherein the polyester-based resin contains a plant-derived polyester-based resin.
<8>
The thermoplastic resin foamed particles according to any one of <1> to <7>, wherein the thermoplastic resin contains a recycled raw material.

<9>
The thermoplastic resin foaming according to any one of <1> to <8>, which comprises a step of extruding and foaming the thermoplastic resin composition containing the thermoplastic resin and a foaming agent to obtain thermoplastic resin foamed particles. How to make particles.
<10>
The method for producing thermoplastic resin foamed particles according to <9>, wherein the thermoplastic resin composition further contains a cross-linking agent.

<11>
Contains thermoplastic resin
The thermoplastic resin contains a polyester-based resin and a polyimide-based resin.
A thermoplastic resin foamed particle molded product having a single glass transition temperature Tg.
<12>
The thermoplastic resin foamed particle molded product according to <11>, wherein the glass transition temperature Tg is 80 to 130 ° C. or lower.
<13>
The thermoplastic resin according to <11> or <12>, wherein the absolute value of the difference between the heat absorption amount and the calorific value obtained by the heat flux differential scanning calorimetry at a heating rate of 10 ° C./min is 3 to 35 J / g. Foamed particle molded body.
<14>
The content ratio of the polyester resin to the total mass of the thermoplastic resin is 40 to 95% by mass.
The content ratio of the polyimide resin to the total mass of the thermoplastic resin is 5 to 60% by mass.
The thermoplastic resin foamed particle molded product according to any one of <11> to <13>.
<15>
The thermoplastic resin foaming according to any one of <11> to <14>, wherein the temperature at which the loss tangent tan δ is maximum in the solid viscoelasticity measurement at a heating rate of 5 ° C./min and a frequency of 1 Hz is 120 to 230 ° C. Particle molded body.
<16>
The thermoplastic resin foamed particle molded product according to any one of <11> to <15>, wherein the polyimide-based resin is a polyetherimide-based resin.
<17>
The thermoplastic resin foamed particle molded body according to any one of <11> to <16>, wherein the polyester-based resin contains a plant-derived polyester-based resin.
<18>
The thermoplastic resin foamed particle molded product according to any one of <11> to <17>, wherein the thermoplastic resin contains a recycled raw material.

<19>
The thermoplastic resin foamed particles are obtained by the method for producing a thermoplastic resin foamed particle according to claim 9 or 10, and the obtained thermoplastic resin foamed particles are filled in a cavity of a mold, and the heat in the cavity is filled. A method for producing a thermoplastic resin foamed particle molded body, wherein the plastic resin foamed particles are heated to form secondary foamed particles, and the secondary foamed particles are heat-sealed to obtain a thermoplastic resin foamed particle molded body.

<20>
A foamed resin having a thermoplastic resin foamed particle molded product according to any one of <11> to <18> and a fiber-reinforced resin layer provided on at least a part of the surface of the thermoplastic resin foamed particle molded product. Complex.

According to the thermoplastic resin foamed particles of the present invention, the heat resistant strength can be improved.

It is a flow chart which shows an example of the manufacturing process of the polyester resin of a plant origin. It is a flow chart which shows an example of the manufacturing process of the polyester resin of a plant origin. It is a flow chart which shows an example of the manufacturing process of the polyester resin of a plant origin. It is a side sectional schematic diagram which shows an example of the manufacturing apparatus of the thermoplastic resin foamed particles of this invention. It is a front schematic diagram which shows an example of the manufacturing apparatus of the thermoplastic resin foamed particles of this invention. It is a front schematic diagram which shows an example of the manufacturing apparatus of the thermoplastic resin foamed particles of this invention. It is sectional drawing of the foamed resin composite which concerns on one Embodiment of this invention. It is a DSC curve of the foamed particle of Example 3. FIG. It is a graph which shows the measurement result of the loss tangent tan δ of Example 3. FIG. It is a graph which shows the measurement result of the loss tangent tan δ of the comparative example 1. FIG.

In this paper, "~" represents a range including the values at both ends as the lower limit value and the upper limit value.

(Thermoplastic resin foam particles)
The thermoplastic resin foamed particles (foamed particles) of the present invention include a thermoplastic resin. The foamed particles are particles obtained by granulating and foaming a thermoplastic resin composition (hereinafter, may be simply referred to as “resin composition”) containing a thermoplastic resin and a foaming agent.
The foamed particles are particulate foams. The foamed particles are used as a raw material for a thermoplastic resin foamed particle molded product (foamed particle molded product) molded by so-called in-mold foam molding.

<Thermoplastic resin>
The thermoplastic resin of the foamed particles includes a polyester-based resin and a polyimide-based resin. The foamed particles of the present invention contain both a polyester-based resin and a polyimide-based resin, so that the heat-resistant strength of the foamed particle molded body can be enhanced.

≪Polyester resin≫
Examples of the polyester resin include polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polyethylene naphthalate resin (PEN), polyethylene furanoate resin (PEF), polybutylene naphthalate resin (PBN), and polytrimethylene terephthalate. Examples thereof include a resin (PTT), a copolymer of terephthalic acid, ethylene glycol and cyclohexanedimethanol, and a mixture thereof. As the polyester-based resin, polyethylene terephthalate resin is preferable, and crystalline polyethylene terephthalate resin (C-PET) is more preferable. C-PET is a polyester-based resin in which the acid component is terephthalic acid and the glycol component is ethylene glycol.
The polyester-based resin may be a polyester-based resin derived from a petrochemical product, a polyester-based resin derived from a plant such as so-called bio-PET, or a mixture thereof.
Examples of the plant-derived polyester resin include polyethylene terephthalate resin, plant-derived polyethylene furanoate resin, and plant-derived polytrimethylene terephthalate resin.
Further, the polyester resin may be a recycled raw material.
These polyester-based resins may be used alone or in combination of two or more.

Hereinafter, the polyester resin derived from plants will be described.
The plant-derived polyester resin is a polymer derived from plant raw materials such as sugar cane and corn. "Derived from plant material" includes polymers synthesized or extracted from plant material. Further, for example, "derived from a plant raw material" includes a polymer obtained by polymerizing a monomer synthesized or extracted from a plant raw material. The "monomer synthesized or extracted from a plant raw material" includes a monomer synthesized from a compound synthesized or extracted from a plant raw material. Plant-derived polyester resins include those in which some of the monomers are "derived from plant raw materials".

A plant-derived polyester resin will be described by taking PET and PEF as an example.

The PET synthesis reaction is shown in Eq. (1). PET is synthesized by a dehydration reaction between n moles of ethylene glycol and n moles of terephthalic acid (Benzene-1,4-dicarboxylAcid). The stoichiometric mass ratio in this synthetic reaction is ethylene glycol: terephthalic acid = 30:70 (mass ratio).

[In the equation (1), n is a stoichiometric coefficient (degree of polymerization), which is a number of 250 to 1100. ]

Ethylene glycol is industrially produced by oxidizing and hydrating ethylene. In addition, terephthalic acid is industrially produced by oxidizing para-xylene.
Here, as shown in FIG. 1, ethylene is obtained by dehydration reaction of plant-derived ethanol (bioethanol), ethylene glycol synthesized from this ethylene (ethylene glycol derived from bioethanol), and terephthal derived from petrochemicals. When synthesizing PET from acid, the PET produced is 30% by mass PET derived from plants.
Further, as shown in FIG. 2, paraxylene is obtained by dehydration reaction of plant-derived isobutanol (bioisobutanol), and PET is synthesized from terephthalic acid synthesized from this paraxylene and ethylene glycol derived from bioethanol. If the PET produced is 100% by mass plant-derived PET.

The PEF synthesis reaction is shown in Eq. (2). PEF is synthesized by a dehydration reaction between n moles of ethylene glycol and n moles of furandicarboxylic acid.

[In equation (2), n is a stoichiometric coefficient (degree of polymerization), which is a number of 250 to 1100. ]

Frangylcarboxylic acid (FDCA) is obtained, for example, by dehydrating plant-derived fructose or glucose to obtain hydroxymethylfurfural (HMF) and oxidizing HMF.
As shown in FIG. 3, when both FDCA and ethylene glycol are derived from plants, the produced PEF is 100% by mass of plant-derived PEF.

The glass transition temperature Tg of the polyester resin is preferably 50 to 100 ° C, more preferably 60 to 90 ° C, still more preferably 70 to 85 ° C. When Tg is at least the above lower limit value, the heat resistance strength and the heating dimensional stability can be further improved. When Tg is not more than the above upper limit value, the molding cycle can be shortened to increase productivity and improve moldability. The "formability" means, for example, that when foamed particles are filled in a mold cavity and heated for secondary foaming, the shape is brought closer to a desired shape, and the closer the shape is to a desired shape. , The moldability is "good".

The melting point of the polyester resin is preferably 230 to 270 ° C, more preferably 240 to 260 ° C, still more preferably 245 to 255 ° C. When the melting point is at least the above lower limit value, the heat resistance strength and the heating dimensional stability can be further improved. When the melting point is not more than the above upper limit value, the molding cycle can be shortened to increase productivity and improve moldability.

The intrinsic viscosity (IV value) of the polyester resin is preferably 0.5 to 1.5, more preferably 0.6 to 1.3, and even more preferably 0.7 to 1.2. When the IV value is equal to or higher than the above lower limit value, defoaming during foaming is suppressed and the open cell ratio can be further lowered. When the IV value is not more than the above upper limit value, the density can be made lower, the surface can be made smoother, and the appearance can be enhanced.
The IV value can be measured by the method of JIS K7367-5 (2000).

The number average molecular weight Mn of the polyester resin is 9,000 to 45,000, preferably 15,000 to 43,000, and more preferably 20,000 to 40,000.
When Mn is at least the above lower limit value, cold resistance (that is, mechanical strength at low temperature) can be further enhanced. When Mn is not more than the above upper limit value, the heat resistance can be further improved.

The Z average molecular weight Mz of the polyester resin is 50,000 to 500,000, preferably 180,000 to 450,000, and more preferably 100,000 to 400,000.
When Mz is within the above range, cold resistance (that is, mechanical strength at low temperature) can be further enhanced.

Mn and Mz can be measured by the following methods.
[Molecular weight of polyester resin]
Take 5 mg of the sample from the measurement target, add 0.5 mL of hexafluoroisopropanol (HFIP) and 0.5 mL of chloroform in this order, and shake lightly and manually. This is left to stand for a soaking time of 24 ± 1.0 hr. After confirming that the sample is completely dissolved, dilute it to 10 mL with chloroform and gently shake it manually to mix. Then, the sample is filtered through a non-aqueous 0.45 μm chromatographic disk manufactured by GL Sciences Co., Ltd. or a non-aqueous 0.45 μm syringe filter manufactured by Shimadzu GLC Co., Ltd. to obtain a measurement sample. The measurement sample is measured by a chromatograph under the following measurement conditions, and the number average molecular weight Mn and Z average molecular weight Mz of the sample are obtained from a standard polystyrene calibration curve prepared in advance.

〔measuring device〕
-Measuring device = "HLC-8320GPC EcoSEC" manufactured by Tosoh Corporation, gel penetration chromatograph (built-in RI detector / UV detector).
[GPC measurement conditions]
・ Column <sample side>
Guard column = TSK guardcolum HXL-H (6.0 mm x 4.0 cm) x 1 manufactured by Tosoh Corporation.
Measurement column = TSKgel GMHXL (7.8 mm ID x 30 cm) manufactured by Tosoh Corporation x 2 in series.
<Reference side>
Resistance tube (inner diameter 0.1 mm x 2 m) x 2 in series.
Column temperature = 40 ° C.
Mobile phase = chloroform.
<Dynamic flow rate>
Sample side pump = 1.0 mL / min.
Reference side pump = 0.5 mL / min.
Detector = UV detector (254 nm).
Injection amount = 15 μL.
Measurement time = 26 minutes.
Sampling pitch = 500 msec.

[Standard polystyrene sample for calibration curve]
The standard polystyrene sample for the calibration curve has a mass average molecular weight Mw of 5,620,000, 3,120,000, and 1 from the product names "STANDARD SM-105" and "STANDARD SH-75" manufactured by Showa Denko KK. , 250,000, 442,000, 131,000, 54,000, 20,000, 7,590, 3,450, 1,320 are used.
The standard polystyrenes for the calibration curve are A (5,620,000, 1,250,000, 131,000, 20,000, 3,450) and B (3,120,000, 442,000, 54,000, Group 7,590,1,320). A is weighed (2 mg, 3 mg, 4 mg, 4 mg, 4 mg) and then dissolved in 30 mL of chloroform. B is weighed (3 mg, 4 mg, 4 mg, 4 mg, 4 mg) and then dissolved in 30 mL of chloroform.
A standard polystyrene calibration curve is obtained by injecting 50 μL of each of the prepared A and B solutions and preparing a calibration curve (third-order formula) from the retention time obtained after the measurement. The number average molecular weight Mn and the Z average molecular weight Mz are calculated using the calibration curve.

The content ratio of the polyester resin to the total mass of the thermoplastic resin contained in the foamed particles is preferably 40 to 95% by mass, more preferably 45 to 90% by mass, further preferably 50 to 80% by mass, and further preferably 50 to 70% by mass. % Is particularly preferable. When the content ratio of the polyester resin is at least the above lower limit value, the moldability can be improved. When the content ratio of the polyester resin is not more than the above upper limit value, the heat resistant strength can be further increased.

≪Polyimide resin≫
The polyimide-based resin is not particularly limited, but is preferably a polymer containing a cyclic imide group as a repeating unit, and preferably a polymer having melt moldability.
Examples of the polyimide resin include US Pat. No. 4,141,927, Japanese Patent No. 2622678, Japanese Patent No. 2606912, Japanese Patent No. 2606914, Japanese Patent No. 2596565, Japanese Patent No. 2596566, and Japanese Patent No. 2598478. Polyetherimide, Patent No. 2598536, Japanese Patent No. 2599171, Japanese Patent Application Laid-Open No. 9-48852, Japanese Patent No. 2565556, Japanese Patent No. 2564636, Japanese Patent No. 2564637, Japanese Patent No. Examples thereof include the polymers described in Japanese Patent No. 2563548, Japanese Patent No. 2563547, Japanese Patent No. 2558341, Japanese Patent No. 2558339, and Japanese Patent No. 2834580. As long as the effect of the present invention is not impaired, the main chain of the polyimide resin may contain a structural unit other than the cyclic imide. Examples of the structural unit other than the cyclic imide include aromatic, aliphatic, alicyclic, alicyclic ester unit, oxycarbonyl unit and the like.
Further, the polyimide resin may be a recycled raw material.
These polyimide-based resins may be used alone or in combination of two or more.

As the polyimide resin, for example, a compound represented by the following formula (3) is preferable.

[In the formula (3), R is an aromatic group having a carbon atom having 6 to 42 carbon atoms, and R'is a divalent aromatic group having 6 to 30 carbon atoms and a fat having 2 to 30 carbon atoms. It is at least one divalent organic group selected from the group consisting of a group group and an alicyclic group group having 4 to 30 carbon atoms. p is a number representing a repeating unit. ]

As the polyimide-based resin, a polyetherimide-based resin having a structural unit having an ether bond is preferable from the viewpoint of enhancing compatibility with the polyester-based resin.

The polyimide resin can be prepared by a conventionally known production method. For example, either or both of tetracarboxylic acid and its acid anhydride, which are raw materials capable of inducing R in the formula (3), and raw materials capable of inducing R'in the formula (3). It is obtained by dehydration condensation of one or more compounds selected from the group consisting of aliphatic primary diamines and aromatic primary diamines. Specifically, as a method for producing a polyimide resin, a method of obtaining a polyamic acid and then heat-closing the ring can be exemplified. Alternatively, a method of chemically closing the ring using an acid anhydride and a chemical ring-closing agent such as pyridine or carbodiimide, the tetracarboxylic acid anhydride and the diisocyanate capable of inducing R'are heated and decarbonated for polymerization. An example of how to do this.

Examples of the tetracarboxylic acid include pyromellitic acid, 1,2,3,4-benzenetetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,2', 3,3'-. Biphenyltetracarboxylic acid, 3,3', 4,4'-benzophenone tetracarboxylic acid, 2,2', 3,3'-benzophenone tetracarboxylic acid, bis (2,3-dicarboxyphenyl) methane, bis (3) , 4-Dicarboxyphenyl) methane, 1,1'-bis (2,3-dicarboxyphenyl) ethane, 2,2'-bis (3,4-dicarboxyphenyl) propane, 2,2'-bis (2,2'-bis ( 2,3-Dicarboxyphenyl) Propane, bis (3,4-dicarboxyphenyl) ether, bis (2,3-dicarboxyphenyl) ether, bis (3,4-dicarboxyphenyl) sulfone, bis (2, 3-Dicarboxyphenyl) sulfone, 2,3,6,7-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 2,2 '-Bis [(2,3-dicarboxyphenoxy) phenyl] propane and its acid anhydrides and the like can be mentioned.

Examples of the diamine include benzidine, diaminodiphenylmethane, diaminodiphenylethane, diaminodiphenylpropane, diaminodiphenylbutane, diaminodiphenylether, diaminodiphenylsulfone, diaminodiphenylbenzophenone, o, m, p-phenylenediamine, tolylene diamine, xylenediamine and the like. And aromatic primary diamines, ethylenediamines, 1,2-propanediamines, 1,3-propanediamines, 2,2-dimethyl-1,3-propanediamines, which have hydrocarbon groups of these aromatic primary diamines as structural units. 1,6-Hexamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 2 , 2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,4-cyclohexanedimethylamine, 2-methyl-1,3 -Examples include cyclohexanediamine, isophorone diamine and the like, their aliphatics, and aliphatic and alicyclic primary diamines having a hydrocarbon group of the alicyclic primary diamine as a structural unit.

The glass transition temperature Tg of the polyimide resin is preferably 190 to 240 ° C., more preferably 200 to 230 ° C., and even more preferably 210 to 220 ° C. When Tg is at least the above lower limit value, the heat resistance strength and the heating dimensional stability can be further improved. When Tg is not more than the above upper limit value, the molding cycle can be shortened to increase productivity and improve moldability.

The melt flow rate (MFR) of the polyimide resin is preferably 3 to 30 g / 10 minutes, more preferably 5 to 25 g / 10 minutes, still more preferably 7 to 20 g / 10 minutes. When the MFR is at least the above lower limit value, the molding cycle can be shortened to increase productivity and improve moldability. When the MFR is not more than the above upper limit value, the heat resistance strength and the heating dimensional stability can be further improved.

The number average molecular weight of the polyimide resin is preferably 5,000 to 50,000, more preferably 6,000 to 39,000, and even more preferably 7,000 to 27,000. If the number average molecular weight of the polyimide resin is at least the above lower limit, the impact resistance can be further enhanced. When the number average molecular weight of the polyimide resin is not more than the above upper limit value, the moldability can be further improved.

The content ratio of the polyimide resin to the total mass of the thermoplastic resin contained in the foamed particles is preferably 5 to 60% by mass, more preferably 10 to 55% by mass, further preferably 20 to 50% by mass, and 30 to 50% by mass. % Is particularly preferable. When the content ratio of the polyimide resin is at least the above lower limit value, the heat resistant strength can be further increased. When the content ratio of the polyimide resin is not more than the above upper limit value, the moldability can be further improved.

The thermoplastic resin contained in the foamed particles may contain a recycled raw material. Either one of the polyester-based resin and the polyimide-based resin may contain the recycled raw material, and both the polyester-based resin and the polyimide-based resin may contain the recycled raw material. A part or all of the polyester resin may be a recycled raw material of the polyester resin, and a part or all of the polyimide resin may be a recycled raw material of the polyimide resin.
Examples of the recycled raw material include the following raw materials.
1) A recovery pellet obtained by remelting a flake-shaped resin obtained by crushing a foam such as foamed particles or a foamed particle molded product with an extruder, extruding it into a strand shape from a nozzle die, cooling the foam, and then pelletizing the resin.
2) Recycled PET obtained by remelting a flake-shaped resin obtained by crushing a PET bottle with an extruder, extruding it into a strand shape from a nozzle die, cooling it, and then pelletizing it.

≪Other resins≫
The foamed particles are substantially free of thermosetting resin. "Substantially free" means that it is not contained at all or is contained to the extent that it does not affect the quality of the foamed particles. The content of the thermosetting resin contained in the foamed particles is preferably 5% by mass or less, more preferably 2% by mass or less, still more preferably 1% by mass or less, and 0% by mass with respect to 100 parts by mass of the thermoplastic resin. Is the most preferable.

The thermoplastic resin may contain a thermoplastic resin (other thermoplastic resin) other than the polyester resin and the polyimide resin. Examples of other thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyphenylene ether resins, polyamide resins, polycarbonate resins, polyarylate resins, polyphenyl sulfone resins, and polysulfone resins. , Polyether sulfone-based resin and the like.

The total ratio of the polyester resin and the polyimide resin to the total mass of the thermoplastic resin is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and most preferably 100% by mass. preferable. When the total ratio of the polyester resin and the polyimide resin is at least the above lower limit value, the heat resistant strength of the foamed particles can be further enhanced.

≪Physical characteristics≫
Effervescent particles exhibit a single glass transition temperature Tg. When the polyester resin and the polyimide resin are compatible with each other, a single glass transition temperature Tg is obtained. Since the glass transition temperature Tg of the foamed particles is single, the glass transition temperature Tg is higher than the glass transition temperature Tg of the polyester resin, and the heat resistance strength of the foamed particle molded body is enhanced.
In addition, "the glass transition temperature is single" means that the temperature is lower than the crystallization peak seen in the second temperature rise process in the heat flux differential scanning calorimetry chart (DSC curve) at a heating rate of 10 ° C./min. It means that it can be recognized that the glass transition temperature Tg in the above is single. However, if no crystallization peak is observed in the second temperature rise process, it means that it can be recognized that the glass transition temperature Tg in the temperature range (30 to 300 ° C.) in the second temperature rise process is single.
The glass transition temperature Tg of the foamed particles is, for example, preferably 80 to 130 ° C., more preferably 85 to 125 ° C., and even more preferably 90 to 120 ° C. When Tg is at least the above lower limit value, the heat resistance strength and the heating dimensional stability of the foamed particle molded product can be further enhanced. When Tg is not more than the above upper limit value, the molding cycle can be shortened to increase productivity and improve moldability.
The glass transition temperature Tg of the foamed particles is determined by measuring the heat flux differential scanning calorimetry at a heating rate of 10 ° C./min.
The glass transition temperature Tg of the foamed particles can be equated with the glass transition temperature Tg of the thermoplastic resin constituting the foamed particles.

The absolute value of the difference between the amount of heat absorption and the amount of heat generated in the foamed particles (heat absorption heat generation difference) is preferably 3 to 35 J / g, more preferably 5 to 25 J / g, and even more preferably 7 to 15 J / g. When the endothermic heat generation difference is at least the above lower limit value, the crystallinity is increased, and the heat resistance strength and the heating dimensional stability of the foamed particle molded body can be further improved. When the endothermic heat generation difference is not more than the above upper limit value, the crystallinity does not increase too much, excellent secondary foamability and heat fusion properties are exhibited, and moldability and mechanical strength can be enhanced.
The endothermic heat generation difference is the difference between the endothermic amount and the calorific value obtained by measuring the heat flux differential scanning calorimetry at a heating rate of 10 ° C./min.
The endothermic heat generation difference in the foamed particles can be equated with the endothermic heat generation difference of the thermoplastic resin constituting the foamed particles.

For the foamed particles, the temperature at which the loss tangent tan δ is maximized in the solid viscoelasticity measurement at a heating rate of 5 ° C./min and a frequency of 1 Hz is preferably 120 to 230 ° C, more preferably 130 to 225 ° C, and more preferably 150 to 220 ° C. More preferred. When the temperature at which the loss tangent tan δ is maximized is at least the above lower limit value, the temperature at which the foamed particle molded body softens becomes high, and the heat resistance strength of the foamed particle molded body can be further increased. When the temperature at which the loss tangent tan δ is maximized is not more than the above upper limit value, the temperature at which the foamed particle compact is softened does not become excessively high, and the moldability can be further improved.
The temperature at which the loss tangent tan δ of the foamed particles is maximized is determined by molding the foamed particle molded body and measuring the solid viscoelasticity of the foamed particle molded body.

<Effervescent agent>
Examples of the foaming agent include saturated aliphatic hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane and hexane, ethers such as dimethyl ether, methyl chloride, 1,1,1,2-tetrafluoroethane, 1 , 1-Difluoroethane, fluorocarbons such as monochlorofluoromethane, carbon dioxide, nitrogen and the like, and dimethyl ether, propane, normal butane, isobutane, carbon dioxide and nitrogen are preferable. These foaming agents may be used alone or in combination of two or more.

The content of the foaming agent is not particularly limited, but is preferably 0.1 to 12 parts by mass with respect to 100 parts by mass of the resin.

<Arbitrary ingredient>
The foamed particles of the present embodiment may contain other components (arbitrary components) other than the thermoplastic resin and the foaming agent.
Optional components include bubble regulators, stabilizers, UV absorbers, colorants, antioxidants, crystallization accelerators, lubricants, cross-linking agents, surfactants, shrinkage inhibitors, flame retardants, deterioration inhibitors and the like. Be done.

Examples of the cross-linking agent include acid dianhydrides such as pyromellitic anhydride, polyfunctional epoxy compounds, oxazoline compounds, and oxazine compounds. By blending a cross-linking agent with the resin composition, defoaming during foaming is suppressed and the open cell ratio can be further lowered.
The content of the cross-linking agent is preferably, for example, 0.08 to 0.8 parts by mass with respect to 100 parts by mass of the resin.

The bubble adjusting agent is, for example, a mixture of inorganic powders such as talc and silica. These bubble adjusting agents increase the closed cell ratio of the foamed particles and easily form the foamed particles.
The content of the bubble adjusting agent is preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the resin.

The stabilizer is, for example, a calcium-zinc-based heat stabilizer, a tin-based heat stabilizer, a lead-based heat stabilizer, or the like.
The content of the stabilizer is preferably, for example, 1 part by mass or less with respect to 100 parts by mass of the resin.

The ultraviolet absorber is, for example, a cesium oxide-based ultraviolet absorber, a titanium oxide-based ultraviolet absorber, or the like.
The content of the ultraviolet absorber is preferably, for example, 1 part by mass or less with respect to 100 parts by mass of the resin.

Antioxidants are, for example, cerium oxide, cerium oxide / zirconia solid solution, cerium hydroxide, carbon, carbon nanotubes, titanium oxide, fullerenes and the like.
The content of the antioxidant is preferably, for example, 1 part by mass or less with respect to 100 parts by mass of the resin.

The colorant is, for example, titanium oxide, carbon black, titanium yellow, iron oxide, ultramarine blue, cobalt blue, fired pigment, metallic pigment, mica, pearl pigment, zinc oxide, precipitated silica, cadmium red and the like.
When the foamed particles of the present embodiment are used in a container for food, it is preferable to select a product registered by the Hygiene Council from the above colorants.
The content of the colorant is preferably, for example, 2 parts by mass or less with respect to 100 parts by mass of the resin.

The crystallization accelerator is, for example, a silicate, carbon, a metal oxide, or the like. Examples of the silicate include talc, which is a hydrous magnesium silicate. Examples of carbon include carbon black, carbon nanofibers, carbon nanotubes, carbon nanohorns, activated carbon, graphite, graphene, coke, mesoporous carbon, glassy carbon, hard carbon, soft carbon and the like, and carbon black includes furnaces. Examples include black, acetylene black, carbon-walled black, and thermal black. Examples of the metal oxide include zinc oxide and titanium oxide.
The content of the crystallization accelerator is preferably, for example, 3 parts by mass or less with respect to 100 parts by mass of the resin.

Each of the above-mentioned optional components may be used alone or in combination of two or more.
The total amount of the optional components contained in the foamed particles is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass with respect to the total mass of the foamed particles.

<Physical characteristics>
The size of the foamed particles is appropriately selected according to the intended use, and the average particle size of the group of foamed particles is, for example, 0.5 to 5 mm.
The average particle size of the group of foamed particles is a value expressed by D50.
Specifically, using a low-tap type sieve shaker (manufactured by Iida Seisakusho Co., Ltd.), the sieve mesh openings are 26.5 mm, 22.4 mm, 19.0 mm, 16.0 mm, 13.2 mm, 11.20 mm, 9. 50 mm, 8.80 mm, 6.70 mm, 5.66 mm, 4.76 mm, 4.00 mm, 3.35 mm, 2.80 mm, 2.36 mm, 2.00 mm, 1.70 mm, 1.40 mm, 1.18 mm, 1.00 mm, 0.85 mm, 0.71 mm, 0.60 mm, 0.50 mm, 0.425 mm, 0.355 mm, 0.300 mm, 0.250 mm, 0.212 mm and 0.180 mm JIS standard sieve (JIS Z8801) -1: 2006), about 25 g of the sample was classified for 10 minutes, and the weight of the sample on the sieve net was measured. A cumulative weight distribution curve is created from the obtained results, and the particle diameter (median diameter) at which the cumulative weight is 50% is defined as the average particle diameter.

The open cell ratio of the foamed particles is preferably 20% or less, more preferably 18% or less, still more preferably 16% or less. When the open cell ratio of the foamed particles is not more than the above upper limit value, the secondary foamability of the foamed particles can be further enhanced, and the moldability and the mechanical strength can be further enhanced. The open cell ratio of the foamed particles is determined by the method described in JIS K7138: 2006 "Hard foamed plastic-How to determine the open cell ratio and the closed cell ratio".

The apparent density of the foamed particles is, for example, preferably 0.027 to 0.675 g / cm ³ , more preferably 0.045 to 0.45 g / cm ³ , and even more preferably 0.0675 to 0.27 g / cm ³ . When the apparent density is at least the above lower limit value, the cushioning power of the foamed particle molded product can be increased. When the apparent density is not more than the above upper limit value, the mechanical strength of the foamed particle molded product can be increased.

The bulk foaming ratio of the foamed particles is, for example, preferably 2 to 50 times, more preferably 3 to 30 times, still more preferably 5 to 20 times. When the bulk foaming ratio is equal to or higher than the above lower limit, the buffering force can be increased. When the bulk foaming ratio is not more than the above upper limit value, the mechanical strength can be increased.

The average bubble diameter of the foamed particles is, for example, preferably 5 to 500 μm, more preferably 10 to 400 μm, and even more preferably 20 to 300 μm. If the average bubble diameter is at least the above lower limit, the buffering power can be increased. When the average bubble diameter is not more than the above upper limit value, the mechanical strength can be increased.
The average cell diameter can be measured according to the test method of ASTM D3576-77.

<Manufacturing method>
As a method for producing foamed particles of the present invention, a resin composition containing a thermoplastic resin and a foaming agent is extruded and foamed to obtain foamed particles, and a thermoplastic resin is extruded to obtain resin particles. Examples thereof include a method of impregnating resin particles with a foaming agent to form foamed particles.
As a more specific method for producing foamed particles, for example, the following method and the like can be mentioned.
1) When the thermoplastic resin and the foaming agent are supplied to the extruder and melt-kneaded, the molten resin composition is extruded into the air through the holes of the die provided at the tip of the extruder to be foamed, and then extruded and foamed. A method of obtaining foamed particles by cutting them at the same time and throwing the cut foamed spherical particles into water to cool them.
2) The thermoplastic resin and the foaming agent are supplied to the extruder and melt-kneaded, and the molten resin composition is extruded into water through the holes of the die provided at the tip of the extruder to be foamed, cooled, and extruded. A method of foaming, cooling, and at the same time cutting to obtain cut foamed spherical foam particles.
3) The thermoplastic resin and the foaming agent are supplied to the extruder and melt-kneaded, and the molten resin composition is extruded into water through the holes of the die provided at the tip of the extruder to be cooled, and at the same time extruded and cooled. A method of cutting to obtain cut spherical effervescent particles and heating the effervescent particles to obtain effervescent particles.
4) The thermoplastic resin is supplied to the extruder and melt-kneaded, and the molten thermoplastic resin is extruded into the air from the hole of the die provided at the tip of the extruder, and is cut at the same time as being extruded, and the cut spherical shape is formed. A method in which resin particles are cast in water and cooled to obtain resin particles, the resin particles are impregnated with a foaming agent to obtain foamable particles, and the foamable particles are heated to obtain foamed particles.
5) The thermoplastic resin is supplied to the extruder and melt-kneaded, and the melted thermoplastic resin is extruded into water from the hole of the die provided at the tip of the extruder to be cooled, extruded and cooled, and at the same time cut and cut. A method in which the formed spherical resin particles are obtained, the resin particles are impregnated with a foaming agent to obtain foamable particles, and the foamable particles are heated to obtain foamed particles.
6) The thermoplastic resin was supplied to the extruder and melt-kneaded, and the melted thermoplastic resin was extruded into a strand shape from the hole of the die provided at the tip of the extruder, and after being extruded, it was guided into water and cooled to be cooled. Later, a method in which columnar resin particles are obtained by cutting at predetermined lengths, the resin particles are impregnated with a foaming agent to obtain foamable particles, and the foamable particles are heated to obtain foamed particles.

Hereinafter, a method of extruding the resin composition into the air to foam it, cutting the resin composition, and throwing spherical particles into water to cool the resin composition will be described in more detail.

The extruder used for producing the foamed particles of the present invention will be described.
The foamed particle manufacturing apparatus 10 of FIG. 4 has an extruder (not shown) and a nozzle mold 1 provided at the tip of the extruder. A rotating shaft 2 is connected to the tip of the nozzle mold 1. The rotary shaft 2 penetrates the front portion 41a of the cooling drum 41 constituting the cooling member 4 described later and is connected to the drive member 3 such as a motor.
On the front end surface 1a of the nozzle mold 1, a plurality of nozzle outlet portions 11 are formed at equal intervals on the same virtual circle A centered on the rotation shaft 2 (see FIG. 5).

The number of nozzles in the nozzle mold 1 (that is, the number of outlet portions 11) is preferably 2 to 80. When the number of nozzles is one, the production efficiency of foamed particles may decrease. If the number is more than 80, the extruded foams extruded from the nozzles adjacent to each other may come into contact with each other and coalesce. In addition, the foamed particles obtained by cutting the extruded foam may coalesce with each other. The number of nozzles is more preferably 5 to 60, and particularly preferably 8 to 50.
The diameter (opening diameter) of the nozzle outlet portion 11 in the nozzle mold 1 is preferably 0.2 to 2 mm. If the opening diameter of the outlet portion 11 is less than 0.2 mm, the extrusion pressure may become too high and extrusion foaming may become difficult. When the opening diameter of the outlet portion 11 is larger than 2 mm, the diameter of the foamed particles may become large and the filling efficiency into the mold may decrease. The opening diameter of the outlet portion 11 is more preferably 0.3 to 1.6 mm, and particularly preferably 0.4 to 1.2 mm.
The length of the land portion of the nozzle mold 1 is preferably 4 to 30 times the opening diameter of the outlet portion 11 of the nozzle of the nozzle mold 1. If the length is less than 4 times, fracture may occur and stable extrusion foaming may not be possible. If it is larger than 30 times, excessive pressure may be applied to the nozzle mold 1 and extrusion foaming may not be possible. The length of the land portion is more preferably 5 to 20 times.

A rotation shaft 2 is arranged in a portion of the front end surface 1a of the nozzle mold 1 surrounded by the nozzle outlet portion 11 so as to project forward.
One or a plurality of rotary blades 5 are integrally provided on the outer peripheral surface of the rear end portion of the rotary shaft 2, and all the rotary blades 5 are in constant contact with the front end surface 1a during the rotation. Will be. When a plurality of rotary blades 5 are integrally provided on the rotary shaft 2, the plurality of rotary blades 5 are arranged at equal intervals in the circumferential direction of the rotary shaft 2. Further, FIG. 5 shows, as an example, a case where four rotary blades 5 are integrally provided on the outer peripheral surface of the rotary shaft 2.
As the rotary shaft 2 rotates, the rotary blade 5 moves on the virtual circle A on which the outlet portion 11 of the nozzle is formed while constantly in contact with the front end surface 1a, and is extruded from the outlet portion 11 of the nozzle. The extruded foam is configured to be able to be cut sequentially and continuously.
The foamed particle manufacturing apparatus 10 is provided with a cooling member 4 that surrounds at least the front end surface 1a of the nozzle mold 1 and the rotating shaft 2. The cooling member 4 has a bottom having a front portion 41a having a front circular shape having a diameter larger than that of the nozzle mold 1 and a cylindrical peripheral wall portion 41b extending rearward from the outer peripheral edge of the front portion 41a. It is provided with a cylindrical cooling drum 41.

A supply port 41c for supplying the cooling liquid 42 is formed in the region of the peripheral wall portion 41b facing the outer surface of the nozzle mold 1. The supply port 41c penetrates the peripheral wall portion 41b. On the outer surface of the peripheral wall portion 41b, a supply pipe 41d for supplying the cooling liquid 42 into the cooling drum 41 is connected to the supply port 41c.
The coolant 42 is configured to be supplied obliquely forward along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 through the supply pipe 41d.

A discharge port 41e is formed on the lower surface of the front end portion of the peripheral wall portion 41b. The discharge port 41e penetrates the peripheral wall portion 41b. On the outer surface of the peripheral wall portion 41b, the discharge pipe 41f is connected to the discharge port 41e.
The extruder is not particularly limited as long as it is a conventional general-purpose extruder, and examples thereof include a single-screw extruder, a twin-screw extruder, and a tandem type extruder in which a plurality of extruders are connected. ..

A method of manufacturing foamed particles using the foamed particle manufacturing apparatus 10 will be described.
The coolant 42 is supplied into the cooling drum 41 from the supply pipe 41d via the supply port 41c. The supplied coolant 42 advances forward (toward the front portion 41a) in a spiral shape along the inner peripheral surface of the peripheral wall portion 41b due to the centrifugal force accompanying the flow velocity at the time of supply. The coolant 42 gradually spreads in a direction orthogonal to the traveling direction (that is, the circumferential direction of the peripheral wall portion 41b) while traveling along the inner peripheral surface of the peripheral wall portion 41b. The coolant 42 spreading in the circumferential direction of the peripheral wall portion 41b completely covers the inner peripheral surface of the peripheral wall portion 41b in front of the supply port 41c.

The coolant 42 is not particularly limited as long as it can cool the foamed particles, and examples thereof include water and alcohol, but water is preferable in consideration of post-use treatment.
The temperature of the coolant 42 is preferably 10 to 40 ° C. When the temperature of the coolant is 10 ° C. or higher, the resin composition can be more smoothly extruded from the outlet portion 11 without excessively cooling the nozzle mold 1 located in the vicinity of the cooling drum 41. When the temperature of the coolant is 40 ° C. or lower, the particulate cut can be cooled more quickly.

While rotating the rotary blade 5, the resin composition is pushed out from the outlet portion 11 of the nozzle.
The glass transition temperature Tg of the polyester resin (raw material polyester resin) blended in the resin composition is preferably 50 to 100 ° C, more preferably 60 to 90 ° C, still more preferably 70 to 85 ° C. When Tg is at least the above lower limit value, the heat resistance strength and the heating dimensional stability can be further improved. When Tg is not more than the above upper limit value, the molding cycle can be shortened to increase productivity and improve moldability. The "formability" means, for example, that when foamed particles are filled in a mold cavity and heated for secondary foaming, the shape is brought closer to a desired shape, and the closer the shape is to a desired shape. , The moldability is "good".

The melting point of the raw material polyester resin is preferably 230 to 270 ° C, more preferably 240 to 260 ° C, still more preferably 245 to 255 ° C. When the melting point is at least the above lower limit value, the heat resistance strength and the heating dimensional stability can be further improved. When the melting point is not more than the above upper limit value, the molding cycle can be shortened to increase productivity and improve moldability.

The intrinsic viscosity (IV value) of the raw material polyester resin is preferably 0.5 to 1.5, more preferably 0.6 to 1.3, and even more preferably 0.7 to 1.2. When the IV value is equal to or higher than the above lower limit value, defoaming during foaming is suppressed and the open cell ratio can be further lowered. When the IV value is not more than the above upper limit value, the density can be made lower, the surface of the foamed particle molded product can be made smoother, and the appearance can be enhanced.
The IV value can be measured by the method of JIS K7367-5 (2000).

The number average molecular weight Mn of the raw material polyester resin is 9,000 to 45,000, preferably 15,000 to 43,000, and more preferably 20,000 to 40,000.
When Mn is at least the above lower limit value, the cold resistance (that is, the mechanical strength at low temperature) of the foamed particle molded product can be further enhanced. When Mn is not more than the above upper limit value, the heat resistance of the foamed particle molded product can be further enhanced.

The Z average molecular weight Mz of the raw material polyester resin is 50,000 to 500,000, preferably 80,000 to 450,000, and more preferably 100,000 to 400,000.
When Mz is within the above range, the cold resistance of the foamed particle molded product can be further enhanced.

The resin composition becomes an extruded foam extruded from the nozzle die 1 and is cut by the rotary blade 5 to become a particulate cut product. All the rotary blades 5 are constantly in contact with the front end surface 1a and rotate, and the extruded foam extruded from the nozzle mold 1 is located between the rotary blade 5 and the end edge of the outlet portion 11 of the nozzle. Due to the shear stress generated, it is cut in the atmosphere at regular time intervals to form particulate cuts. At this time, water may be sprayed onto the extruded foam in the form of mist within a range in which the extruded foam is not excessively cooled.

The resin composition is prevented from foaming in the nozzle of the nozzle mold 1. Immediately after being ejected from the outlet portion 11 of the nozzle, the resin composition has not yet foamed, and begins to foam after a short time has elapsed after being ejected. Therefore, the extruded foam comprises an unfoamed portion immediately after being ejected from the outlet portion 11 of the nozzle, and a foamed portion that is continuous with the unfoamed portion and is extruded prior to the unfoamed portion.
The unfoamed portion maintains that state from the time when the nozzle is discharged from the outlet portion 11 until the start of foaming. The time for maintaining this unfoamed portion can be adjusted by adjusting the resin pressure at the outlet portion 11 of the nozzle, the amount of foaming agent, and the like. When the resin pressure at the outlet portion 11 of the nozzle is high, the resin composition does not foam immediately after being extruded from the nozzle mold 1 and maintains an unfoamed state. The discharge pressure of the thermoplastic resin at the outlet portion 11 of the nozzle can be adjusted by adjusting the opening diameter of the outlet portion 11 of the nozzle, the extrusion rate, the melt viscosity of the resin composition, and the melt tension. In addition, by adjusting the amount of the foaming agent to an appropriate amount, it is possible to prevent the thermoplastic resin fat composition from foaming inside the nozzle mold 1 and reliably form an unexpanded portion.
Since all the rotary blades 5 cut the extruded foam in a state of being in constant contact with the front end surface 1a, the extruded foam was cut at the unfoamed portion immediately after being ejected from the outlet portion 11 of the nozzle. It becomes a granular cut piece.

The rotation speed of the rotary blade 5 is preferably 2000 to 10000 rpm, more preferably 2000 to 9000 rpm, and particularly preferably 2000 to 8000 rpm. When the number of rotations is equal to or higher than the above lower limit, the extruded foam can be more reliably cut by the rotary blade 5, preventing coalescence, and forming the foamed particles into a more uniform shape. When the rotation speed is not more than the above upper limit value, a sufficient time to reach the coolant 42 described later is sufficiently secured, and the bulk foaming ratio can be further increased.

As shown in FIG. 6, the particulate cut piece P cut by the rotary blade 5 is scattered toward the inner wall of the cooling drum 41 at the same time as cutting due to the cutting stress by the rotary blade 5, and the inner peripheral surface of the peripheral wall portion 41b is scattered. It collides with the coolant 42 to be coated. The particulate cuts continue to foam until they collide with the coolant 42, and the particulate cuts grow substantially spherical by foaming. Therefore, the obtained foamed particles are substantially spherical. At this time, it is preferable that the particulate cut piece P is oblique to the surface of the coolant 42 and collides with the coolant 42 from upstream to downstream in the flow direction X of the coolant 42 (FIG. 6). reference). When the particulate cuts collide with the coolant 42, the particulate cuts P collide with the coolant 42 from the direction of following the flow of the coolant 42, so that the particulate cuts P come into contact with the surface of the coolant 42. Without being repelled, the particulate cuts P smoothly and reliably enter the coolant 42 and are cooled by the coolant 42 to become foamed particles.

According to the present embodiment, after the extruded foam is cut by the rotary blade 5, the particulate cut is immediately cooled by the coolant 42, so that the particulate cut is prevented from being excessively foamed. , Foaming particles having a desired bulk foaming ratio can be obtained.
In addition, since the particulate cuts are cooled immediately after cutting the extruded foam, the increase in the crystallinity of the foamed particles is suppressed. Therefore, the foamed particles exhibit excellent secondary foaming property and heat fusion property, and the obtained foamed particle molded product has excellent mechanical strength. Further, by increasing the crystallinity of the foamed particle molded product of the polyester resin during in-mold foam molding, the heating dimensional stability can be further enhanced.

The foamed particles cooled by the coolant 42, together with the coolant 42, flow into the discharge pipe 41f through the discharge port 41e and are discharged to the outside of the cooling drum 41. The discharged foam particles are separated from the coolant 42 and dried if necessary. Examples of the method for separating the foamed particles and the cooling liquid 42 include conventionally known solid-liquid separation methods such as passing through a sieve.

(Thermoplastic resin foamed particle molded product)
The thermoplastic resin foamed particle molded body (foamed particle molded body) of the present embodiment is formed by foaming foamed particles and fusing them together. Examples of the foamed particle molded body include parts of transportation equipment such as automobiles, aircraft, railroad vehicles, and ships, cushioning materials for electric products, housings, and the like. Examples of automobile parts include members used in the vicinity of an engine, exterior materials, heat insulating materials, and the like. Further, for example, examples of the foamed particle molded body include food packaging containers such as fish boxes and vegetable boxes, cushioning materials used for electric products, packaging materials, structural members, heat insulating materials and the like.

The size of the foamed particle molded product is not particularly limited and is appropriately determined in consideration of the intended use.

The foamed particle compact exhibits a single glass transition temperature Tg. When the polyester resin and the polyimide resin are compatible with each other, a single glass transition temperature Tg is obtained. Since the glass transition temperature Tg of the foamed particle molded body is single, the glass transition temperature Tg is higher than the glass transition temperature Tg of the polyester resin, and the heat resistance strength of the foamed particle molded body is enhanced.
The glass transition temperature Tg of the foamed particle molded product is, for example, preferably 80 to 130 ° C., more preferably 85 to 125 ° C., and even more preferably 90 to 120 ° C. When Tg is at least the above lower limit value, the heat resistance strength and the heating dimensional stability of the foamed particle molded product can be further enhanced. When Tg is not more than the above upper limit value, the moldability is improved and the appearance is beautifully finished.

The endothermic heat generation difference of the foamed particle molded product is preferably 3 to 35 J / g, more preferably 10 to 30 J / g, and even more preferably 15 to 28 J / g. When the endothermic heat generation difference is at least the above lower limit value, the crystallinity is increased and the heating dimensional stability of the foamed particle molded product can be improved. When the endothermic heat generation difference is not more than the above upper limit value, the crystallinity does not increase too much, and the impact resistance of the foamed particle molded product can be enhanced.
The endothermic heat generation difference is the difference between the endothermic amount and the calorific value obtained by measuring the heat flux differential scanning calorimetry at a heating rate of 10 ° C./min.

In the foamed particle molded body, the temperature at which the loss tangent tan δ is maximized in the solid viscoelasticity measurement at a heating rate of 5 ° C./min and a frequency of 1 Hz is preferably 120 to 230 ° C, more preferably 130 to 225 ° C, and 150 to 220. ° C is more preferred. When the temperature at which the loss tangent tan δ is maximized is at least the above lower limit value, the temperature at which the foamed particle molded body softens becomes high, and the heat resistance strength of the foamed particle molded body can be further increased. When the temperature at which the loss tangent tan δ is maximized is not more than the above upper limit value, the temperature at which the foamed particle compact is softened does not become excessively high, and the moldability can be further improved.

The open cell ratio of the foamed particle molded product is, for example, preferably 20% or less, more preferably 18% or less, still more preferably 16% or less. When the open cell ratio of the foamed particle molded product is not more than the above upper limit value, the impact resistance of the foamed particle molded product can be further enhanced. The open cell ratio of the foamed particle molded body is determined by the method described in JIS K7138: 2006 "Hard foamed plastic-How to determine the open cell ratio and the closed cell ratio".

The apparent density of the foamed particle molded body is, for example, preferably 0.027 to 0.675 g / cm ³ , more preferably 0.045 to 0.45 g / cm ³ , and further preferably 0.0675 to 0.27 g / cm ³ . preferable. When the apparent density of the foamed particle molded product is at least the above lower limit value, the impact resistance of the foamed particle molded product can be further enhanced. When the apparent density of the foamed particle molded product is not more than the above upper limit value, the foamed particle molded product can be made lighter.

The foaming ratio of the foamed particle molded product is, for example, preferably 2 to 50 times, more preferably 3 to 30 times, still more preferably 5 to 20 times. When the expansion ratio of the foamed particle molded product is at least the above lower limit value, the impact resistance of the foamed particle molded product can be further enhanced. When the expansion ratio of the foamed particle molded product is not more than the above upper limit value, the mechanical strength of the foamed particle molded product can be further increased.

The average bubble diameter of the foamed particle molded product is, for example, preferably 5 to 500 μm, more preferably 10 to 400 μm, and even more preferably 20 to 300 μm. When the average bubble diameter of the foamed particle molded body is at least the above lower limit value, the impact resistance of the foamed particle molded body can be further enhanced. When the average cell diameter of the foamed particle molded body is not more than the above upper limit value, the surface smoothness of the foamed particle molded body can be further enhanced.
The average cell diameter of the foamed particle molded product can be measured according to the method described in ASTM D2842-69.

<Manufacturing method>
The foamed particle molded product using the foamed particles can be manufactured by a conventionally known manufacturing method.
Examples of the method for producing the foamed particle molded product include the following methods.
1) Foaming particles (bulk foaming ratio: 2 to 50 times) are filled in a molding mold, and the foaming particles are secondarily foamed to form secondary foaming particles and fused to form in-mold foaming. A method of forming a foamed particle molded body (foaming ratio: 2 to 50 times) by molding (heat molding step).
2) Pre-foamed particles heated to an arbitrary bulk-foaming ratio (bulk-foaming ratio: 2 to 50 times) (preliminary foaming step), and the pre-foaming particles are filled in a mold and then filled. Method of heating to secondary foam the prefoamed particles to form secondary foamed particles and fusing them to obtain a foamed particle molded body (expansion ratio: 2 to 50 times) by in-mold foam molding (heat molding step). ..

Examples of the method of secondary foaming include a method of heating the inside of the mold cavity with steam.
The temperature for secondary foaming is preferably, for example, 100 to 180 ° C.
The time for secondary foaming (that is, the time for supplying steam to the mold) is preferably 5 to 120 seconds.
In the secondary foaming, water vapor may be supplied into the cavity from the female mold side, steam may be supplied into the cavity from the male mold side, or these may be alternately performed.
Further, the foamed particles may be impregnated with an inert gas or air (hereinafter referred to as an inert gas or the like) to improve the secondary foaming power of the foamed particles (internal pressure applying step). Examples of the inert gas include carbon dioxide, nitrogen, helium, argon and the like.
As a method of impregnating the foamed particles with an inert gas or the like, for example, a method of impregnating the foamed particles with the inert gas or the like by placing the foamed particles in an atmosphere such as an inert gas having a pressure higher than normal pressure is used. Can be mentioned. The foamed particles may be impregnated with an inert gas or the like before being filled in the mold, but are impregnated by placing the foamed particles in an atmosphere such as an inert gas together with the mold after being filled in the mold. May be good. When the inert gas is nitrogen, the foamed particles may be left for 20 minutes to 24 hours in a nitrogen atmosphere having a gauge pressure (based on atmospheric pressure) of 0.1 to 2 MPa.

Following the heat molding step, the crystallinity of the thermoplastic resin may be increased by further heating the foamed particle molded body in the mold (heat retention step).

(Foam resin complex)
The foamed resin composite has a foamed particle molded product of the present invention and a fiber reinforced resin layer (skin material) provided on at least a part of the surface of the foamed particle molded product.
The foamed resin composite has excellent heat resistance and mechanical strength, and can be widely used as a member for constructing transportation equipment. In addition, foamed resin composites include building materials, windmill wings, robot arms, housings for electrical products, cushioning materials for helmets, agricultural products boxes, transport containers such as heat and cold insulation containers, rotor blades for industrial helicopters, and parts packaging materials. Can also be suitably used.
Examples of the transportation equipment component include structural members constituting the main body of the transportation equipment such as an automobile, an aircraft, a railroad vehicle, or a ship. Examples of structural members constituting the main body of an automobile include door panels, door inners, bumpers, fenders, fender supports, engine covers, roof panels, trunk lids, floor panels, center tunnels, crash boxes, cowls and the like. For example, if a resin composite is used for a door panel made of steel plate in the past, the rigidity is substantially the same as that of the door panel made of steel plate, and the weight can be significantly reduced, so that the weight of the automobile can be reduced.

For example, the foamed resin composite 100 of FIG. 7 has a flat plate-shaped foamed particle molded body (foamed layer) 102 and a fiber reinforced resin layer 104 provided on both sides of the foamed particle molded body 102.

The foamed layer 102 is the foamed particle molded product of the present invention described above.
The fibers constituting the fiber reinforced resin layer 104 are not particularly limited, and examples thereof include carbon fibers, glass fibers, aramid fibers, boron fibers, and metal fibers. Of these, carbon fiber, glass fiber, and aramid fiber are preferable, and carbon fiber is more preferable, because they have excellent mechanical strength and heat resistance.
The form of the fiber is not particularly limited, and for example, a woven fabric, a knitted fabric, a non-woven fabric, and a fiber bundle (strand) in which fibers are arranged in one direction are stitched with a synthetic resin thread such as a polyamide resin or a polyester resin or a glass fiber thread. Examples thereof include a face material that is bound (sewn) with a thread. Examples of the weaving method of the woven fabric include plain weave, twill weave, satin weave and the like.
The fibers are (1) a multilayer surface material formed by laminating a plurality of textiles, knitted fabrics or nonwoven fabrics or any combination thereof, and (2) a fiber bundle (strand) in which fibers are aligned in one direction is a polyamide resin. A plurality of face materials bound (sewn) with synthetic resin threads such as polyester resin or stitch threads such as glass fiber threads were overlapped and overlapped so that the fiber directions of the fiber bundles pointed to different directions. It may be a multilayer face material in which face materials are integrated (sewn) with a synthetic resin thread such as a polyamide resin or a polyester resin or a stitch thread such as a glass fiber thread.

Examples of the resin contained in the fiber reinforced resin layer 104 include an uncured thermosetting resin and a thermoplastic resin. The thermosetting resin is not particularly limited, and is not particularly limited, for example, epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicon resin, maleimide resin, vinyl ester resin, cyanate ester resin, maleimide resin and cyanide. Examples thereof include a resin obtained by prepolymerizing an acid ester resin. Epoxy resins and vinyl ester resins are preferable because they are excellent in heat resistance, elastic modulus and chemical resistance. The thermosetting resin may contain additives such as a curing agent and a curing accelerator. The thermosetting resin may be used alone or in combination of two or more.
The thermoplastic resin is not particularly limited, and examples thereof include polyethylene-based resins, polyolefin-based resins such as polypropylene-based resins, acrylic-based resins, polyester-based resins, polyamide-based resins, and polycarbonate-based resins.
The resin content of the fiber reinforced resin layer 104 is preferably 20 to 70% by mass, more preferably 30 to 60% by mass, based on the total mass of the fiber reinforced resin layer 104. When the resin content is at least the above lower limit, the bonds between the fibers are further enhanced, and the mechanical strength of the obtained foamed resin composite is further enhanced. When the resin content is not more than the above upper limit, the amount of the resin existing between the fibers does not become too large, the mechanical strength of the fiber reinforced resin layer 104 is further increased, and the mechanical strength of the obtained foamed resin composite is further increased. It will increase.

The method of impregnating the fiber with the resin is not particularly limited, and examples thereof include (1) a method of immersing the fiber in the resin, and (2) a method of applying the resin to the fiber.

In the present embodiment, the materials of the fiber reinforced resin layers located on both sides of the foamed particle molded product may be the same or different from each other.

The thickness of the fiber reinforced resin layer 104 is preferably, for example, 0.1 to 5 mm, more preferably 0.3 to 3 mm. When the thickness of the fiber reinforced resin layer 104 is at least the above lower limit value, the mechanical strength of the foamed resin composite 100 can be further increased. When the thickness of the fiber reinforced resin layer 104 is not more than the above upper limit value, the weight of the foamed resin composite 100 can be further reduced.
In the present embodiment, the thicknesses of the fiber-reinforced resin layers 104 located on both sides of the foamed particle molded body 102 may be the same or different from each other.

<Manufacturing method>
The method of providing the fiber-reinforced resin layer 104 on the surface of the foamed particle molded body 102 is not particularly limited, and for example, (1) the fiber-reinforced resin layer 104 is laminated on the surface of the foamed particle molded body 102 via an adhesive. (2) Fiber reinforced resin layer 104 impregnated with a thermoplastic resin is laminated on the surface of the foamed particle molded body 102, and the fiber reinforced resin is used as a binder on the surface of the foamed particle molded body 102. Method for joining the resin layer 104, (3) A fiber-reinforced resin layer 104 impregnated with an uncured heat-curable resin is laminated on the surface of the foamed particle molded body 102, and the cured product of the heat-curable resin is used as a binder. A method of joining the fiber-reinforced resin layer 104 to the foamed particle molded body 102, (4) The fiber-reinforced resin layer 104 in a heated and softened state is laminated on the surface of the foamed particle molded body 102, and the surface of the foamed particle molded body 102 is laminated. Examples thereof include a method of joining the fiber-reinforced resin layer 104 to the foamed particle molded body 102 by pressing the fiber-reinforced resin layer 104. In the method (4), the fiber reinforced resin layer 104 can be deformed along the surface of the foamed particle molded body 102. Here, since the foamed particle molded product 102 of the present invention is excellent in load bearing capacity in a high temperature environment, the method (4) can also be preferably used.
By these methods, the fiber reinforced resin layer 104 is integrally provided on the surface of the foamed particle molded body 102.
Examples of the method for joining the fiber reinforced resin layer 104 to the surface of the foamed particle molded body 102 include an autoclave method, a hand lay-up method, a spray-up method, a PCM (Prepreg Compression Molding) method, and an RTM (Resin Transfer Molding) method. The VaRTM (Vacum assisted Resin Transfer Molding) method and the like can be mentioned.

The foamed resin composite of the above-described embodiment has a flat-plate-shaped foamed particle molded product, but the present invention is not limited to this, and the shape of the foamed particle molded product can be appropriately determined depending on the intended use. That is, the shape of the foamed resin complex can be appropriately determined according to the intended use.
In the above-described embodiment, the fiber-reinforced resin layer is provided on both sides of the foamed particle molded product, but the present invention is not limited to this, and the fiber-reinforced resin layer is provided on only one side of the foamed particle molded product. Alternatively, the fiber reinforced resin layer may be provided only on a part of the surface of the foamed particle molded product.

In the foamed particles of the present embodiment, the polyester resin and the polyimide resin are compatible with each other, and the thermoplastic resin has a single glass transition temperature. Therefore, the glass transition temperature is higher than the glass transition temperature Tg of the polyester resin. The temperature becomes Tg, and the heat resistance can be increased. Therefore, the foamed particle molded product obtained by heat-molding the foamed particles has excellent heat resistance.
In addition, the foamed particles of the present embodiment exhibit excellent heat-resistant strength without requiring a heat retention step, so that the productivity of the foamed particle molded body can be enhanced. The foamed particle molded product of the present embodiment exhibits excellent heat resistance even when the crystallinity is less than 20%.
Further, the foamed particle molded product of the present embodiment is manufactured through a heat retention step, so that the degree of crystallinity is increased and the heating dimensional stability is further improved.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

(Raw materials used)
<Polyester resin>
-PET (A): manufactured by Far Eastern New Century, trade name "CH-611", glass transition temperature Tg: 78 ° C, melting point: 251 ° C, IV value: 1.02, biomass degree: 0%.
-PET (B): manufactured by INDRAMA, trade name "RAMA PET N1B", glass transition temperature Tg: 78 ° C., melting point: 247 ° C., IV value: 0.80, biomass degree: 30%.
-PET (C): manufactured by Far Eastern New Century, trade name "CH-653", glass transition temperature Tg: 79 ° C, melting point: 248 ° C, IV value: 1.01, biomass degree: 27 to 30%.
-PET (D): manufactured by Farto Ishizuka Greenpet Co., Ltd., trade name "CB-603RJ", glass transition temperature Tg: 79 ° C, melting point: 248 ° C, IV value: 0.80, biomass degree: 0%, PET bottle Recycled recycled PET.

<Polyimide resin>
-PEI (A): polyetherimide, manufactured by SABIC Innovative Plastics, trade name "Ultem1000", glass transition temperature Tg: 217 ° C., MFR: 9 g / 10 minutes.
-PEI (B): polyetherimide, manufactured by SABIC Innovative Plastics, trade name "Ultem1010", glass transition temperature Tg: 217 ° C., MFR: 17.8 g / 10 minutes.

<Amorphous polyester resin>
-PCT (G): manufactured by Eastman Chemical Company, trade name "Traitan TX-1001", aromatic dicarboxylic acid component = terephthalic acid, diol component = 1,4-cyclohexanedimethanol and 2,2,4,4-tetramethyl -1,3-Cyclobutanediol, glass transition temperature Tg: 107 ° C., IV value: 0.72.

<Talc Masterbatch>
-Talc MB: A masterbatch consisting of PET = 72% by mass and talc = 28% by mass.

<Crosslinking agent>
-PMDA: Piromellitic anhydride.

(Evaluation method of foamed particles)
<Bulk density>
The bulk density of the foamed particles was measured according to JIS K6911: 1995 "General Test Method for Thermosetting Plastics". The measurement was performed using an apparent density measuring device compliant with JIS K6911, and the bulk density of the foamed particles was determined based on the following equation (s1).
Bulk density of foamed particles (kg / m ³ ) = [Mass of graduated cylinder containing foamed particles (kg) -Mass of graduated cylinder (kg)] / [Capacity of graduated cylinder (m ³ )] ... (s1) )

<Bulk foaming ratio>
The bulk foaming ratio of the foamed particles was a value obtained by determining the density of the thermoplastic resin from the blending ratio of each example and dividing the density of the thermoplastic resin by the bulk density of the obtained foamed particles. The following values were used for the density of each resin.
-PET: 1.35 g / cm ³ .
-PEI: 1.28 g / cm ³ .
-PCT: 1.18 g / cm ³ .

<Continuous bubble rate>
The open cell ratio of the foamed particles was measured by the following method. First, a sample cup of a volumetric air comparison hydrometer was prepared, and the total mass A (g) of the foamed particles in an amount satisfying about 80% of the sample cup was measured. Next, the volume B (cm ³ ) of the entire foamed particles was measured by the 1-1 / 2-1 atm method using a hydrometer. For the measurement, "Volume measurement air comparison type hydrometer 1000 type" of Tokyo Science Co., Ltd. was used.
A wire mesh container was prepared, the wire mesh container was immersed in water, and the mass C (g) of the wire mesh container in the state of being immersed in the water was measured. All the foamed particles are put in this wire mesh container, the wire mesh container is immersed in water, and the wire mesh container in the state of being immersed in water and the total amount of foamed particles put in this wire mesh container are mixed. The combined mass D (g) was measured. An "electronic balance HB3000" (minimum scale 0.01 g) manufactured by Yamato Scale Co., Ltd. was used for measuring the mass of the foamed particles and the wire mesh container.
Then, the apparent volume E (cm ³ ) of the foamed particles is calculated based on the following formula, and the open cells of the foamed particles are calculated by the following formula (s2) based on the apparent volume E and the volume B (cm ³ ) of the entire foamed particles. The rate was calculated. The volume of 1 g of water was set to 1 cm ³ . Further, in this measurement, the foamed particles were stored in advance in a JISK710-1999 symbol 23/50, second grade environment for 16 hours, and then the measurement was carried out in the same environment.
Continuous bubble ratio (%) = 100 × (EB) / E ... (s2)
(E = A + (CD))

<Melting point, crystallization temperature, glass transition temperature Tg>
The melting point, crystallization temperature and glass transition temperature Tg were measured by the methods described in JIS K7121: 1987 and JIS K7121: 2012. However, the sampling method and temperature conditions are as follows.
The sample cut out from the foamed particles or the foamed particle molded body was filled in the bottom of the aluminum measuring container in an amount of 5.5 ± 0.5 mg so as to have no gap, and then covered with an aluminum lid. Next, a differential scanning calorimetry was performed using a "DSC7000X, AS-3" differential scanning calorimeter manufactured by Hitachi High-Tech Science Corporation. The sample was heated and cooled in the following steps 1 to 4 under a nitrogen gas flow rate of 20 mL / min to obtain a DSC curve.
(Step 1) Hold at 30 ° C for 2 minutes.
(Step 2) The temperature is raised from 30 ° C. to 300 ° C. at a rate of 10 ° C./min (first temperature rise process) and held for 10 minutes.
(Step 3) The sample is quickly taken out and allowed to cool in an environment of 25 ± 10 ° C.
(Step 4) Temperature rise from 30 ° C. to 300 ° C. at a rate of 10 ° C./min (second temperature rise process).
Alumina was used as a reference material. Using the analysis software attached to the device, as shown in FIG. 8 (measurement result of Example 3), read the temperature of the top of the melting peak and the crystallization peak seen in the second temperature raising process, and determine the melting point and the crystallization temperature. bottom. For the glass transition temperature Tg, the intermediate point glass transition temperature was calculated from the DSC curve observed in the second temperature rise process using the analysis software attached to the device. This midpoint glass transition temperature was determined from the standard (9.3).
For the glass transition temperature Tg, the glass transition temperature Tg on the lower temperature side than the crystallization peak seen in the second temperature rise process is adopted in the heat flux differential scanning calorimetry chart (DSC curve) at a heating rate of 10 ° C./min. bottom. However, when no crystallization peak was observed in the second temperature rise process, the glass transition temperature Tg in the temperature range (30 to 300 ° C.) in the second temperature rise process was adopted.

<Heat absorption (a), calorific value (b), crystallinity>
The amount of heat absorbed (a) (heat of melting) and the amount of heat generated (b) (heat of crystallization) were measured by the methods described in JIS K7121: 1987 and JIS K7121: 2012. However, the sampling method and temperature conditions are as follows.
The sample cut out from the foamed particles or the foamed particle molded body was filled in the bottom of the aluminum measuring container in an amount of 5.5 ± 0.5 mg so as to have no gap, and then covered with an aluminum lid. Next, a differential scanning calorimetry was performed using a "DSC7000X, AS-3" differential scanning calorimeter manufactured by Hitachi High-Tech Science Corporation. The sample was heated and cooled in steps 1 and 2 below under a nitrogen gas flow rate of 20 mL / min to obtain a DSC curve.
(Step 1) Hold at 30 ° C for 2 minutes.
(Step 2) The temperature is raised from 30 ° C. to 300 ° C. at a speed of 10 ° C./min (first temperature rise process).
Alumina was used as the reference material at this time. The heat absorption amount (a) and the calorific value (b) were calculated using the analysis software attached to the apparatus. Specifically, as shown in FIG. 4, the heat absorption amount (a) is a straight line connecting a point where the DSC curve separates from the baseline on the low temperature side and a point where the DSC curve returns to the baseline on the high temperature side again. It was calculated from the area of the part surrounded by the DSC curve. The calorific value (b) was calculated from the area of the portion surrounded by the DSC curve and the straight line connecting the point where the DSC curve separates from the baseline on the low temperature side and the point where the DSC curve returns to the high temperature side again.
The crystallinity is determined by the following method. First, the difference between the heat absorption amount (a) and the heat generation amount (b) is obtained. The crystallinity is defined as the ratio obtained by dividing this difference by the theoretical melting heat of 140.1 J / g of the polyethylene terephthalate perfect crystal.
That is, the crystallinity is obtained from the following equation (s3).
Crystallinity (%) = (heat absorption (a) (J / g) -calorific value (b) (J / g)) /140.1 (J / g) × 100 ... (s3)

(Evaluation method of foamed particle molded product)
<Density>
The density of the foamed particle compact was measured by the method described in JIS K7222: 1999 "Foam Plastics and Rubber-Measurement of Apparent Density". A foamed particle compact of 100 cm ³ or more was cut so as not to change the original cell structure of the material, and its mass was measured. The density was calculated by the following equation (s4).
Density (g / cm ³ ) = Mass of foamed particle molded body (g) / Volume of foamed particle molded body (cm ³ ) ... (s4)

<Effervescence magnification>
The bulk foaming ratio of the foamed particle molded body was a value obtained by determining the density of the thermoplastic resin from the blending ratio of each example and dividing the density of the thermoplastic resin by the density of the obtained foamed particle molded body. The following values were used for the density of each resin.
-PET: 1.35 g / cm ³ .
-PEI: 1.28 g / cm ³ .
-PCT: 1.18 g / cm ³ .

<Measurement of solid viscoelasticity>
For the solid viscoelasticity measurement, a "EXSTRAR DMS6100" viscoelasticity spectrometer manufactured by SII Nanotechnology Co., Ltd. was used. The surface skin layer was removed from the foamed particle molded product, and a columnar sample having a diameter of about 10 mm and a thickness of about 2 mm was cut out. The conditions were as follows.
-Mode: Compression control mode.
・ Atmosphere: Nitrogen atmosphere.
-Frequency: 1Hz.
-Raising rate: 5 ° C / min.
-Measurement temperature: 30 ° C to 300 ° C.
-Strain amplitude: 5 μm.
-Minimum compressive force: 100 mN.
-Tension gain: 1.5.
-Initial force amplitude: 100 mN.
For the analysis, the analysis software attached to the device was used. The temperature at which the loss tangent tan δ is maximum is the value read as the maximum temperature in the measured value of the loss tangent tan δ in the temperature range of 50 to 240 ° C.
A “DIGIMATIC” CD-15 type manufactured by Mitutoyo Corporation was used for measuring the dimensions of the test piece.

<Heating dimensional change rate (evaluation of heating dimensional stability)>
The rate of change in heating dimensions of the foamed particle molded product was measured by the method B described in JIS K6767: 1999 "Effervescent Plastic-Polyethylene-Test Method". A test piece having a planar shape of 150 mm on a side and having a thickness of the thickness of the foamed particle molded body was cut out from the foamed particle molded body. Three 100 mm straight lines parallel to each other were drawn at 50 mm intervals in the vertical and horizontal directions of the central portion of the test piece. The lengths of the three straight lines were measured in the vertical direction and the horizontal direction, respectively, and their arithmetic mean value L0 was used as the initial dimension. Then, the test piece was left in a hot air circulation type dryer set at 100 ° C. and 120 ° C. for 168 hours to perform a heating test. After the heating test, the test piece was taken out, and the test piece was left at 25 ° C. for 1 hour. Next, the lengths of the three straight lines in the vertical direction and the horizontal direction written on the surface of the test piece were measured, and their arithmetic mean value L1 was taken as the dimension after heating. The heating dimensional change rate was calculated based on the following equation (s5).
Heating dimensional change rate (%) = 100 × | (L1-L0) | / L0 ... (s5)
Based on the results of the measurement of the rate of change in heating dimensions of the foamed particle molded product at each set temperature, the evaluation was made according to the following criteria.

≪Judgment criteria≫
⊚: The rate of change in heating dimensions is less than 1.0%.
◯: The heating dimension change rate is 1.0% or more and less than 1.5%.
Δ: The heating dimension change rate is 1.5 or more and less than 2.0.
X: The heating dimension change rate is 2.0 or more.

<Bending elastic modulus (heat resistance)>
The flexural modulus in the bending test was measured according to the method described in JIS K7221-1: 2006. The flexural modulus was measured using "Autograph AG-X plus 100kN" universal testing machine manufactured by Shimadzu Corporation and "TRAPEZIUM X" universal testing machine manufactured by Shimadzu Corporation. The test piece was cut out from the foamed particle molded body in a size of 25 mm in width × 130 mm in length × 20 mm in thickness. The test speed was 10 mm / min. The radius of the pressure wedge and the tip of the support base was 5R. The distance between the fulcrums was 100 mm. The test piece was used for the measurement after adjusting the condition for 16 hours under the symbol "23/50" of JIS K7100: 1999 under the standard atmosphere of the second grade.
The measurement was carried out in a standard atmosphere and at 80 ° C. At 80 ° C, after adjusting the condition for 24 hours in a constant temperature bath set at 80 ° C, take out the test piece from the constant temperature bath and immediately place the test piece in the jig installed in the "TCR2A type" attached constant temperature bath manufactured by Shimadzu Corporation. It was placed and held for 3 minutes before measurement. The number of test pieces at the atmospheric temperature was 5 each.
The flexural modulus was calculated by the universal testing machine data processing in which the load region where the inclination of the portion where the load-strain relationship is straight is maximized was set. The arithmetic mean of the flexural modulus measurements in each test piece was taken as the flexural modulus.
Using the flexural modulus (E80) at 80 ° C. and the flexural modulus (E23) under a standard atmosphere (23 ° C.), the retention rate was calculated based on the following equation (s6).
Retention rate (%) = (E80) / (E23) × 100 ... (s6)
Based on the results of the retention rate of the flexural modulus of the foamed particle molded product, it was evaluated according to the following criteria.

≪Judgment criteria≫
⊚: The retention rate is 80% or more.
◯: The retention rate is 75% or more and less than 80%.
Δ: The retention rate is 70% or more and less than 75%.
X: The retention rate is less than 70%.

<Appearance>
The surface of the foamed particle molded product was visually confirmed and evaluated according to the following criteria.
≪Judgment criteria≫
⊚: There are no gaps between the foamed particles, the surface of the molded body is very smooth, and the appearance of the molded body is very good.
◯: The gap between the foamed particles is very small, the surface of the molded product is almost smooth, and the appearance of the molded product is good.
Δ: There are few gaps between the foamed particles, there are small irregularities on the surface of the molded body, and the appearance of the molded body is slightly inferior.
X: There are many gaps between the foamed particles, the surface of the molded product has large irregularities, and the appearance of the molded product is significantly inferior.

<Comprehensive evaluation>
The evaluation results of heating dimensional change rate, flexural modulus and appearance were classified according to the following evaluation criteria.

≪Evaluation criteria≫
⊚: The evaluation of all items was "◎".
〇: The evaluation of all items was "◎" or "○", and one or more was "○".
Δ: There was no “x” in the evaluation of all items, and there was one or more “Δ” in the evaluation of any item.
X: The evaluation of any of the items was "x".

(Example 1)
Using the same manufacturing apparatus as the foamed particle manufacturing apparatus 10 shown in FIGS. 3 to 5, foamed particles were produced by the following procedure.
First, according to the formulation in the table, polyester resin, polyimide resin, talc masterbatch and cross-linking agent are extruded from a single shaft having a cylinder diameter D of 65 mm and an L (cylinder length) / D (cylinder diameter) ratio of 34. They were supplied to the machine and these were melt-kneaded at 290 ° C. Subsequently, from the middle of the extruder, butane (isobutane: normal butane = 35: 65 (mass ratio)) as a foaming agent is press-fitted into the melt-kneaded product in a molten state so as to have the amount in the table, and the melt-kneaded product. It was uniformly dispersed in the resin composition to obtain a resin composition. Then, at the front end portion of the extruder, the temperature of the molten resin composition was set to 300 ° C., and then the resin composition was extruded and foamed from each nozzle of the multi-nozzle type nozzle mold 1 attached to the front end of the extruder. The extrusion rate of the resin composition was 30 kg / h.
The nozzle mold 1 has 20 nozzles having an outlet portion 11 having a diameter of 1 mm, and all the outlet portions 11 are located at equal intervals on a virtual circle A having a diameter of 139.5 mm. .. Two rotary blades 5 are integrally provided on the outer peripheral surface of the rear end portion of the rotary shaft 2 with a phase difference of 180 ° in the circumferential direction of the rotary shaft 2, and each rotary blade 5 is provided with a nozzle metal. It was configured to move on the virtual circle A in a state of being in constant contact with the front end surface 1a of the mold 1.

The cooling member 4 includes a cooling drum 41 including a front portion 41a having a circular front surface and a cylindrical peripheral wall portion 41b extending rearward from the outer peripheral edge of the front portion 41a and having an inner diameter of 320 mm. rice field. Then, the coolant 42 at 20 ° C. was supplied into the cooling drum 41 through the supply pipe 41d and the supply port 41c of the cooling drum 41. The volume in the cooling drum 41 was 17684 cm ³ .
The coolant 42 draws a spiral along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 due to the centrifugal force accompanying the flow velocity when the coolant 42 is supplied from the supply pipe 41d to the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41. I was heading forward. The coolant 42 gradually spreads in a direction orthogonal to the traveling direction while traveling along the inner peripheral surface of the peripheral wall portion 41b, and covers the entire inner peripheral surface of the peripheral wall portion 41b in front of the supply port 41c of the cooling drum 41. Was covered with.

The rotary blade 5 arranged on the front end surface 1a is rotated at a rotation speed of 3400 rpm, and the extruded foam extruded from the outlet portion 11 of each nozzle of the nozzle mold 1 is cut by the rotary blade 5 to be substantially spherical. A particulate cut was produced. The extruded foam was composed of an unexpanded portion immediately after being extruded from the nozzle of the nozzle mold 1 and a foamed portion in the process of being continuously expanded to the unexpanded portion. The extruded foam was cut at the open end of the outlet portion 11 of the nozzle, and the extruded foam was cut at the unfoamed portion.
In the production of the foamed particles described above, first, the rotating shaft 2 was not attached to the nozzle mold 1 and the cooling member 4 was retracted from the nozzle mold 1. In this state, the resin composition is extruded from an extruder to form an extruded foam, and the unexpanded portion immediately after being extruded from the nozzle of the nozzle mold 1 and the foamed portion in the process of being continuously expanded to the unexpanded portion. It was confirmed that it consisted of. Next, after the rotary shaft 2 is attached to the nozzle mold 1 and the cooling member 4 is arranged at a predetermined position, the rotary shaft 2 is rotated, and the extruded foam is placed at the opening end of the outlet portion 11 of the nozzle by the rotary blade 5. It was cut to produce a particulate cut.

This particulate cut piece is blown outward or forward by the cutting stress of the rotary blade 5, and the flow of the coolant 42 flows into the coolant 42 flowing along the inner surface of the cooling drum 41 of the cooling member 4. It collides with the surface of the coolant 42 from an oblique direction so as to follow the coolant 42 from the upstream side to the downstream side, and the particulate cut pieces enter the coolant 42 and are immediately cooled to be foamed particles. Was manufactured.
The obtained foamed particles were discharged together with the coolant 42 through the discharge port 41e of the cooling drum 41, and then separated from the coolant 42 by a dehydrator.

An in-mold foam molding machine equipped with a mold (male mold and female mold) was prepared. In a state where the male mold and the female mold were molded, a rectangular parallelepiped-shaped cavity having internal dimensions of 300 mm in length × 400 mm in width × 30 mm in height was formed between the male and female molds.
Then, after filling the mold with foamed particles with the mold cracking removed by 3 mm, steam is introduced from the female mold so that the inside of the cavity becomes 0.08 MPa (gauge pressure) for 30 seconds (on the other hand, heating), and then , Water vapor is introduced from the male mold to 0.08 MPa (gauge pressure) in the cavity for 30 seconds (reverse one-sided heating), and then from both male and female molds to 0.12 MPa (gauge pressure) in the cavity. Steam was supplied to the water vapor for 30 seconds (double-sided heating), and the foamed particles were heated and secondarily foamed to integrate the secondary foamed particles by heat fusion. Then, after holding for 300 seconds in a state where the introduction of water vapor into the cavity is stopped (heat retention step), finally, a cooling liquid is supplied into the cavity to cool the foamed particle molded body in the mold, and then the cavity. Was opened and the foamed particle molded product was taken out.
At this time, the time (molding cycle time) required to obtain the foamed particle molded body from the step of filling the foamed particles in the mold was 600 seconds.

(Examples 2 to 3, 6, 8 to 9, 11 to 13, Comparative Examples 1 and 3 to 4)
Foamed particles and foamed particle molding in the same manner as in Example 1 except that the polyester resin, polyimide resin, talc masterbatch, cross-linking agent and foaming agent were blended in the table and the molding conditions shown in the table were used. The body was made.
FIG. 9 shows the measurement result of the loss tangent tan δ of Example 3, and FIG. 10 shows the measurement result of the loss tangent tan δ of Comparative Example 1.

(Example 4)
Using the same foamed particles as in Example 3, a foamed particle molded product was produced in the same manner as in Example 1 except that the molding conditions in the table were set.

(Example 5)
The particles were prepared as foamed particles in the same manner as in Example 1 except that the polyester resin, the polyimide resin, the talc masterbatch, the cross-linking agent and the foaming agent were blended in the table. The prepared foamed particles were allowed to stand in a constant temperature bath at 150 ° C. for 1 hour to foam the foamed particles to obtain preliminary foamed particles. The physical characteristics of the obtained preliminary foamed particles are shown in the table.
The prefoamed particles were left at room temperature (23 ° C.) for 1 day, sealed in a pressure vessel, the inside of the pressure vessel was replaced with nitrogen gas, and then the impregnation pressure (gauge pressure) was up to 0.5 MPa. It was press-fitted, allowed to stand in an environment of 20 ° C., and pressure-cured for 8 hours. (Internal pressure applying step) After that, the preliminary foamed particles were taken out from the pressure vessel.
When the preliminary foamed particles subjected to the internal pressure applying step were secondarily foamed by heating with steam of 0.30 MPa (gauge pressure) for 30 seconds, the secondary foaming property was almost the same as that of the foamed particles obtained in Example 3. It was confirmed.
Using the preliminary foamed particles subjected to the internal pressure applying step, a foamed particle molded product was produced in the same manner as in Example 1 except that the molding conditions shown in the table were met.

(Example 7)
Using the same foamed particles as in Example 6, a foamed particle molded product was produced in the same manner as in Example 1 except that the molding conditions shown in the table were used.

(Example 10)
The same foamed particles as in Example 3 were remelted by a twin-screw extruder, extruded into strands from a nozzle die, cooled, and then pelletized to prepare recovered pellets. Effervescent particles and an effervescent particle molded product were produced in the same manner as in Example 1 except that the formulation and molding conditions in the table were followed.

(Comparative Example 2)
Using the same foamed particles as in Comparative Example 1, a foamed particle molded product was produced in the same manner as in Example 1 except that the molding conditions shown in the table were used.

(Comparative Example 5)
Using the same foamed particles as in Comparative Example 4, a foamed particle molded product was produced in the same manner as in Example 1 except that the molding conditions shown in the table were used.

In Examples 1 to 13 to which the present invention was applied, the evaluation of the heat resistant strength (flexural modulus) was "Δ" to "◎", and the overall evaluation was "Δ" to "◎".
In Comparative Examples 1 and 2 not including PEI and Comparative Examples 3 to 5 in which the glass transition temperature was not single, the evaluation of the heat resistant strength (flexural modulus) was "x", and the overall evaluation was "x".
From the above results, it was confirmed that the heat resistant strength of the thermoplastic resin foamed particle molded product can be enhanced by applying the present invention.

(Example 14)
<Preparation of foamed resin complex>
A fiber reinforced resin layer forming material (CFRP, Mitsubishi) with a thickness of 0.22 mm, which contains 40% by mass of an uncured epoxy resin as a thermosetting resin in a fiber reinforced base material made of a twill weave made of carbon fiber. "Pyrofil prepreg TR3523 381GMX" manufactured by Rayon Co., Ltd., with a grain size of 200 g / m ² ) was prepared. Two layers of a fiber-reinforced resin layer forming material are placed on both sides of the foamed particle molded body obtained in Example 3 to form a laminated body, and the fiber-reinforced resin layer forming material is bonded to the surface of the foamed particle molded body by an autoclave method. bottom. Specifically, the laminate is pressurized to a gauge pressure of 0.3 MPa to apply a pressing force to the laminate, and the laminate is heated at 130 ° C. for 60 minutes to have thermosetting properties in the fiber-reinforced resin layer forming material. The resin was cured, and the fiber-reinforced resin layer forming material was bonded to both sides of the foamed particle molded product with the cured thermosetting resin.
By visually observing the appearance of the obtained foamed resin composite, it was confirmed that the foamed resin composite having no unevenness on the surface of the skin material and having a beautiful appearance was obtained.

100 Foamed resin composite 102 Foamed particle molded body 104 Fiber reinforced resin layer

Claims (20)

Contains thermoplastic resin
The thermoplastic resin contains a polyester-based resin and a polyimide-based resin.
Thermoplastic resin foamed particles having a single glass transition temperature Tg. The thermoplastic resin foamed particles according to claim 1, wherein the glass transition temperature Tg is 80 to 130 ° C. The thermoplastic resin foamed particles according to claim 1 or 2, wherein the absolute value of the difference between the heat absorption amount and the calorific value obtained by the heat flux differential scanning calorimetry at a heating rate of 10 ° C./min is 3 to 35 J / g. The content ratio of the polyester resin to the total mass of the thermoplastic resin is 40 to 95% by mass.
The content ratio of the polyimide resin to the total mass of the thermoplastic resin is 5 to 60% by mass.
The thermoplastic resin foamed particles according to any one of claims 1 to 3. The thermoplastic resin foaming according to any one of claims 1 to 4, wherein the temperature at which the loss tangent tan δ is maximized in the solid viscoelasticity measurement at a heating rate of 5 ° C./min and a frequency of 1 Hz is 120 to 230 ° C. particle. The thermoplastic resin foamed particles according to any one of claims 1 to 5, wherein the polyimide-based resin is a polyetherimide-based resin. The thermoplastic resin foamed particles according to any one of claims 1 to 6, wherein the polyester-based resin contains a plant-derived polyester-based resin. The thermoplastic resin foamed particles according to any one of claims 1 to 7, wherein the thermoplastic resin contains a recycled raw material. The thermoplastic resin foaming according to any one of claims 1 to 8, further comprising a step of extruding and foaming the thermoplastic resin composition containing the thermoplastic resin and the foaming agent to obtain thermoplastic resin foamed particles. How to make particles. The method for producing thermoplastic resin foamed particles according to claim 9, wherein the thermoplastic resin composition further contains a cross-linking agent. Contains thermoplastic resin
The thermoplastic resin contains a polyester-based resin and a polyimide-based resin.
A thermoplastic resin foamed particle molded product having a single glass transition temperature Tg. The thermoplastic resin foamed particle molded product according to claim 11, wherein the glass transition temperature Tg is 80 to 130 ° C. or lower. The thermoplastic resin foamed particles according to claim 11 or 12, wherein the absolute value of the difference between the heat absorption amount and the calorific value obtained by the heat flux differential scanning calorimetry at a heating rate of 10 ° C./min is 3 to 35 J / g. Molded body. The content ratio of the polyester resin to the total mass of the thermoplastic resin is 40 to 95% by mass.
The content ratio of the polyimide resin to the total mass of the thermoplastic resin is 5 to 60% by mass.
The thermoplastic resin foamed particle molded product according to any one of claims 11 to 13. The thermoplastic resin foaming according to any one of claims 11 to 14, wherein the temperature at which the loss tangent tan δ is maximized in the solid viscoelasticity measurement at a heating rate of 5 ° C./min and a frequency of 1 Hz is 120 to 230 ° C. Particle molded body. The thermoplastic resin foamed particle molded product according to any one of claims 11 to 15, wherein the polyimide-based resin is a polyetherimide-based resin. The thermoplastic resin foamed particle molded body according to any one of claims 11 to 16, wherein the polyester-based resin contains a plant-derived polyester-based resin. The thermoplastic resin foamed particle molded product according to any one of claims 11 to 17, wherein the thermoplastic resin contains a recycled raw material. The thermoplastic resin foamed particles are obtained by the method for producing a thermoplastic resin foamed particle according to claim 9 or 10, and the obtained thermoplastic resin foamed particles are filled in a cavity of a mold, and the heat in the cavity is filled. A method for producing a thermoplastic resin foamed particle molded body, wherein the plastic resin foamed particles are heated to form secondary foamed particles, and the secondary foamed particles are heat-sealed to obtain a thermoplastic resin foamed particle molded body. A foamed resin having a thermoplastic resin foamed particle molded product according to any one of claims 11 to 18 and a fiber-reinforced resin layer provided on at least a part of the surface of the thermoplastic resin foamed particle molded product. Complex.

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