WO2020065485A1

WO2020065485A1 - Expanded particles and expanded molded article

Info

Publication number: WO2020065485A1
Application number: PCT/IB2019/058012
Authority: WO
Inventors: 田積皓平; 景山大地; 安東真由美
Original assignee: 積水化成品工業株式会社
Priority date: 2018-09-28
Filing date: 2019-09-23
Publication date: 2020-04-02

Abstract

The present invention relates to expanded particles and an expanded molded article. More specifically, the present invention relates to: expanded particles including a polycarbonate resin as the base resin and having a specific cell density X and a specific average cell wall thickness; and an expanded molded article. The present invention also relates to: expanded particles including a polycarbonate resin as the base resin and having a specific bulk expansion ratio and a specific average cell diameter; and an expanded molded article.

Description

Expanded particles and expanded molded articles

The present invention relates to expanded particles and expanded molded articles. More specifically, the present invention relates to a foamed molded article using a polycarbonate-based resin as a base resin, having a good appearance and high mechanical strength, and suppressing fluctuations in mechanical strength from low to high temperatures, and the foamed molded article. The present invention relates to foamed particles that can produce a body with good moldability.

This application filed Japanese Patent Application No. 2018-185200 filed on Sep. 28, 2018, Japanese Patent Application No. 2019-058518 filed on Mar. 26, 2019, and filed on Mar. 28, 2019. Based on Japanese Patent Application No. 2019-064060, Japanese Patent Application No. 2019-067036 filed on Mar. 29, 2019, and Japanese Patent Application No. 2019-141409 filed on Jul. 31, 2019. Claim the priority and use their contents here.

Foamed molded products are light, have good workability and shape retention, and have relatively high strength. ing. In particular, when heat resistance is not required, a foamed molded article made of a polystyrene resin is used, and when cushioning properties, recoverability, flexibility, etc. are required, a foamed molded article made of an olefin resin such as polypropylene or polyethylene is used. Tend to be used.
Polycarbonate resins are generally resins having higher heat resistance than polystyrene resins and olefin resins. This is a resin material that can be used even in a severe climate such as a dry zone or a tropical zone. This polycarbonate-based resin is not only excellent in heat resistance but also excellent in water resistance, electrical properties, mechanical strength, aging resistance and chemical resistance. For this reason, polycarbonate-based resins have been used as interior materials for buildings so far, but in recent years, applications to automobile members, packaging materials, various containers, and the like utilizing their excellent properties are also expected.

By the way, as a method for producing a foamed molded article of a polycarbonate resin, for example, an in-mold foaming molding method in which foamed particles are foamed and fused in a mold is known. In this method, a mold having a space corresponding to a desired shape is prepared, the foamed particles are filled in the space, and the foamed particles are foamed and fused by heating, so that a foam molded article having a complicated shape is formed. Can be obtained. However, this method has a problem that the appearance of the foamed molded article is not good and the fusion of the foamed particles is not sufficient.
Therefore, the applicant of the present application has proposed a technique for improving the fusion property between foamed particles to provide a foamed molded article having a good appearance (see Patent Document 1).
In addition, examples of foamed molded articles obtained by the in-mold foam molding method include those using a polystyrene-based resin as a base resin (see, for example, Patent Document 2) and those using a polyolefin-based resin as a base resin (see, for example, Patent Literature 2). 3) are known.

Japanese Patent Application Laid-Open No. 2006-188321 Japanese Patent Application Laid-Open No. 2018-100380 Japanese Patent Application Laid-Open No. Hei 11-349724

In Patent Literature 1, a foamed molded article having a good appearance is obtained, but a foamed molded article having a better appearance and higher mechanical strength is provided by further improving the fusion property between foamed particles. Was desired.

In addition, a foamed molded product using a polystyrene-based resin or a polyolefin-based resin as a base resin has good mechanical strength near normal temperature (about 23 ° C.), but has a lower mechanical strength at lower or higher temperatures. The target strength sometimes decreased. Therefore, it has been desired to provide a foam molded article in which the fluctuation of the mechanical strength is suppressed even when the environmental temperature changes.

In view of the above problems, the present inventors have studied the polycarbonate resin to be used, and as a result, by setting the cell density X and the average cell wall thickness of the expanded particles to specific ranges, a foamed molded article obtained from the expanded particles is obtained. It has been surprisingly found that the appearance and the mechanical strength can be improved, and that the fusion property between the foamed particles can be improved.
Thus, according to the present invention, foamed particles using a polycarbonate resin as a base resin,
The foam particles,
(I) A bubble density X of 1.0 × 10 ⁶ / cm ³ or more and less than 1.0 × 10 ⁸ / cm ³ [The bubble density X is represented by the following formula:
Bubble density X = (ρ / D-1) / {(4/3) · π · (C / 100000/2) ³ }
(Where C is the average cell diameter (μm), ρ is the density of the polycarbonate resin (kg / m ³ ), and D is the apparent density of the expanded particles (kg / m ³ ))
Calculated by
(Ii) Foamed particles having an average cell wall thickness of 1 to 15 μm (hereinafter sometimes referred to as “first foamed particles”) are provided.

In addition, the present inventors can improve the appearance and mechanical strength of a foamed molded article obtained from the foamed particles by setting the bulk multiple and the average cell diameter of the foamed particles to a specific range, and at the same time, the mutual expansion of the foamed particles can be improved. It has surprisingly been found that the fusing property can be improved.
Thus, according to the present invention, foamed particles using a polycarbonate resin as a base resin,
The foamed particles have a value in the range of 2.5 to 12 μm / times when the average cell diameter of the foamed particles is divided by the bulk multiple of the foamed particles, 2 foamed particles ").

Further, according to the present invention, there is provided an expanded foam obtained from the expanded particles.
Further, a foam molded article obtained from a plurality of foam particles using a polycarbonate resin as a base resin,
The foamed molded article measures the maximum point stress value of the four-point bending test at each temperature of −40 ° C., 23 ° C., 80 ° C., and 140 ° C., and determines the maximum point of the four-point bending test. When the average value of the stress is calculated, the foamed molded article is characterized by showing the rate of change of the maximum point stress value of the four-point bending test with respect to the average value in the range of 0 to 50%. You.

According to the present invention, the appearance and mechanical strength of a polycarbonate-based resin as a base resin are good, and a foamed molded article having improved fusion property, and a polycarbonate-based resin capable of producing a foamed molded article with good moldability. Expanded particles can be provided.

In addition, in any of the following cases, a foamed molded article having a polycarbonate resin as a base resin, having better appearance and mechanical strength, and further improved fusion bonding property, and a foamed molded article having better moldability are produced. It is possible to provide a foamed particle of a polycarbonate-based resin that can be used.
(1) The foamed particles have an apparent density of 20 to 640 kg / m ³ .
(2) The average cell diameter is 20 to 200 μm, and the density of the polycarbonate resin is 1.0 × 10 ³ to 1.4 × 10 ³ kg / m ³ .
(3) The foamed particles exhibit a cell number density of 1.0 × 10 ⁷ to 1.0 × 10 ⁹ / cm ³ .
(4) The expanded particles have a bulk factor of 2 to 20 times.
(5) The expanded particles have an open cell ratio of 0 to 10%.

Further, according to the present invention, it is possible to provide a foam molded article in which a change in mechanical strength is suppressed even when an environmental temperature changes.

Further, in any of the following cases, it is possible to provide a foamed molded article in which fluctuations in mechanical strength are further suppressed even when the environmental temperature changes.
(1) The foamed molded article has an open cell ratio of 0 to 50%.
(2) The foamed molded product has a foaming multiple of 3 to 30 times.
(3) The foamed molded product is divided into four values of the maximum point stress of the bending test by the density of the foamed molded product, respectively, to obtain four points of “maximum point stress / density of the bending test” and four points of “bending”. When the average value of the “maximum stress / density of the test” is calculated, the rate of change of the value of the “maximum stress / density of the bending test” at four points with respect to the average value in the range of 0 to 50% is shown.
(4) The polycarbonate resin has an MFR of 1.0 to 15.0 g / 10 min.
(5) The “maximum point stress of the bending test” at −40 ° C. changes within the range of 0 to 0.88 with respect to the “maximum point stress of the bending test” at 23 ° C.

4 is a photograph of a cut surface of the foamed particles and foamed molded products of Examples 1a to 3a. 4 is a photograph of a cut surface of the foamed particles and foamed molded products of Examples 4a to 6a. 4 is a photograph of a cut surface of a foamed particle and a foamed molded product of Comparative Examples 1a to 3a. 4 is a photograph of a cut surface of a foamed particle and a foamed molded product of Examples 1b to 6b. 9 is a photograph of a cut surface of the foamed particles and foamed molded products of Examples 7b to 9b. 5 is a photograph of a cut surface of a foamed particle and a foamed molded product of Comparative Examples 1b to 3b.

1. Expanded Particles The expanded particles of the present invention include first expanded particles and second expanded particles. In the present specification, the first expanded particles and the second expanded particles may be simply referred to as “expanded particles”.
First, the first expanded particles in the present invention have a specific cell density X and an average cell wall thickness using a polycarbonate resin as a base resin. The present inventors have found that by adjusting the cell density X and the average cell wall thickness, the appearance and mechanical strength of the foamed molded article can be improved, and the fusion property between the foamed particles can be further improved. .
Further, the second expanded particles in the present invention have a specific bulk multiple and an average cell diameter using a polycarbonate resin as a base resin. The present inventors have found that by adjusting the bulk multiple and the average cell diameter, the appearance and mechanical strength of the foamed molded article can be improved, and the fusion property between the foamed particles can be further improved.

1-1. Bubble density X
Cell density X can be a 1.0 × 10 ⁶ cells / cm ³ or more 1.0 × 10 below ⁸ / cm ^3. If the bubble density X is less than 1.0 × 10 ⁶ cells / cm ³ , it may be difficult to increase the magnification. When the cell density X is 1.0 × 10 ⁸ cells / cm ³ or more, the cell wall thickness may be small and the moldability may be poor. The preferred bubble density X is 2.0 × 10 ⁶ / cm ³ or more and less than 1.0 × 10 ⁸ / cm ³ , and the more preferred bubble density X is 5.0 × 10 ⁶ / cm ³ to 8.0. × 10 ⁷ pieces / cm ³ .
Here, the bubble density X is represented by the following formula:
Bubble density X = (ρ / D-1) / {(4/3) · π · (C / 100000/2) ³ }
Can be calculated by In the formula, C denotes the average cell diameter (mm), ρ denotes the density of the polycarbonate resin (kg / m ³ ), and D denotes the apparent density of the expanded particles (kg / m ³ ).
The average cell diameter C is preferably in the range of 20 to 200 μm. The more preferable average cell diameter C is 40 to 180 μm, and the more preferable average cell diameter C is 50 to 150 μm.

The density ρ of the polycarbonate resin is preferably in the range of 1.0 × 10 ³ to 1.4 × 10 ³ kg / m ³ . When the density ρ is less than 1.0 × 10 ³ kg / m ³ , the heat resistant temperature may decrease. When the density ρ is greater than 1.4 × 10 ³ kg / m ³ , the heat-resistant temperature increases, and foam molding may be difficult. A more preferable density ρ is 1.10 × 10 ³ to 1.35 × 10 ³ kg / m ³ , and a still more preferable density ρ is 1.15 × 10 ³ to 1.30 × 10 ³ kg / m ³ .
The apparent density D of the expanded particles is preferably in the range of 20 to 640 kg / m ³ . When the apparent density D is less than 20 kg / m ³ , the cell membrane becomes thin, the cell membrane is broken at the time of molding, the proportion of open cells increases, and shrinkage of the foam particles due to buckling of the cells may occur. When the apparent density D is larger than 640 kg / m ³ , the thickness of the cell membrane may be increased and the moldability may be reduced. A more preferred apparent density D is 40 to 400 kg / m ³ , and a still more preferred apparent density D is 50 to 200 kg / m ³ .
Further, the bulk density of the expanded particles is preferably in the range of 12 to 600 kg / m ³ . When the bulk density is less than 12 kg / m ³ , the cell membrane becomes thin, the cell membrane is broken at the time of molding, the ratio of open cells increases, and shrinkage of foam particles due to buckling of cells may occur. When the bulk density is larger than 600 kg / m ³ , the foam film may be thick and the moldability may be reduced. More preferred bulk density of 24 ~ 240kg / ^{m 3,} more preferred bulk density is 30 ~ 120kg / ^{m 3.}

1-2. Average Cell Wall Thickness The average cell wall thickness can be 1 to 15 μm. If the average cell wall thickness is less than 1 μm, the moldability during molding, especially fusion, may be poor. When the average cell wall thickness is larger than 15 μm, it may be difficult to increase the magnification. A preferable average cell wall thickness is 1 to 10 μm, and a more preferable average cell wall thickness is 1 to 5 μm.

1-3. The value obtained by dividing the average cell diameter of the expanded particles by the bulk multiple of the expanded particles The value obtained by dividing the average cell diameter of the expanded particles by the volume multiple of the expanded particles indicates a value in the range of 2.5 to 12 μm / times. When the value is less than 2.5 μm / times, the cell membrane becomes thin, the cell membrane is broken at the time of molding, the proportion of open cells increases, and shrinkage of the foam particles due to buckling of the cells may occur. When the value is more than 12 μm / times, the thickness of the bubble film may be increased and the moldability may be reduced. The value is preferably from 3.0 to 10.0 μm / fold, more preferably from 3.0 to 6.5 μm / fold.
The bulk factor is preferably in the range of 2 to 20 times. When the bulk multiple is less than twice, the foam film may be thick and the moldability may be reduced. When the bulk factor is larger than 20, the cell membrane becomes thin, the cell membrane is broken at the time of molding, the ratio of open cells increases, and shrinkage of the foam particles due to buckling of the cells may occur. The bulk factor is more preferably 3 to 18 times, and even more preferably 5 to 16 times.
The average bubble diameter is preferably in the range of 20 to 200 μm. When the average cell diameter is less than 20 μm, the cell membrane becomes thin, the cell membrane is broken at the time of molding, the ratio of open cells increases, and shrinkage of the foam particles due to buckling of the cells may occur. When the average cell diameter is larger than 200 μm, the cell membrane may be thick and the moldability may be reduced. The average bubble diameter is more preferably from 20 to 150 μm, even more preferably from 30 to 120 μm.

1-4. Bubble number density The bubble number density preferably ranges from 1.0 × 10 ⁷ to 1.0 × 10 ⁹ cells / cm ³ . If the bubble number density is less than 1.0 × 10 ⁷ cells / cm ³ , it may be difficult to increase the magnification. When the cell density is 1.0 × 10 ⁹ cells / cm ³ or more, the cell wall thickness may be small, and the moldability may be poor. The bubble number density is more preferably 3.0 × 10 ⁷ to 5.0 × 10 ⁸ cells / cm ³ .
Here, the bubble number density is calculated by the following formula:
Bubble number density = (ρ / D−1) / {(4/3) · π · (C / 100000/2) ³ }
Can be calculated by In the formula, C denotes the average cell diameter (mm), ρ denotes the density of the polycarbonate resin (kg / m ³ ), and D denotes the apparent density of the expanded particles (kg / m ³ ).

The average cell diameter C is preferably in the range of 20 to 200 μm.
The density ρ of the polycarbonate resin is preferably in the range of 1.0 × 10 ³ to 1.4 × 10 ³ kg / m ³ . When the density ρ is less than 1.0 × 10 ³ kg / m ³ , the heat resistant temperature may decrease. When the density ρ is greater than 1.4 × 10 ³ kg / m ³ , the heat-resistant temperature increases, and foam molding may be difficult. The density ρ is more preferably 1.10 × 10 ³ to 1.35 × 10 ³ kg / m ³ , and still more preferably 1.15 × 10 ³ to 1.30 × 10 ³ kg / m ^3. .
The apparent density D of the expanded particles is preferably in the range of 20 to 640 kg / m ³ . When the apparent density D is less than 20 kg / m ³ , the cell membrane becomes thin, the cell membrane is broken at the time of molding, the proportion of open cells increases, and shrinkage of the foam particles due to buckling of the cells may occur. When the apparent density D is larger than 640 kg / m ³ , the thickness of the cell membrane may be increased and the moldability may be reduced. The apparent density D is more preferably from 40 to 400 kg / m ³ , even more preferably from 50 to 250 kg / m ³ .
The thickness of the cell wall is preferably in the range of 1 to 15 μm. If the average cell wall thickness is less than 1 μm, the moldability during molding, particularly fusion, may be poor. When the average cell wall thickness is larger than 15 μm, it may be difficult to increase the magnification. The average cell wall thickness is more preferably 1 to 10 μm, and further preferably 1 to 5 μm.

1-5. Open cell ratio The open cell ratio is preferably 0 to 10%. When the open cell ratio is more than 10%, the moldability of the foamed molded article may be reduced. The open cell ratio is more preferably 0 to 5%.

1-6. Polycarbonate Resin The polycarbonate resin serving as the base resin of the expanded particles may be a linear polycarbonate resin or a branched polycarbonate resin.
The polycarbonate resin preferably has a polyester structure of carbonic acid and glycol or dihydric phenol. The polycarbonate resin may have an aliphatic skeleton, an alicyclic skeleton, an aromatic skeleton, or the like. From the viewpoint of further improving heat resistance, the polycarbonate resin preferably has an aromatic skeleton. Specific examples of the polycarbonate resin include 2,2-bis (4-oxyphenyl) propane, 2,2-bis (4-oxyphenyl) butane, 1,1-bis (4-oxyphenyl) cyclohexane, Examples thereof include polycarbonate resins derived from bisphenols such as 1-bis (4-oxyphenyl) butane, 1,1-bis (4-oxyphenyl) isobutane, and 1,1-bis (4-oxyphenyl) ethane.
The polycarbonate-based resin may include a resin other than the polycarbonate resin. Other resins include acrylic resins, saturated polyester resins, ABS resins, polystyrene resins, polyolefin resins, polyphenylene oxide resins, and the like. The polycarbonate resin preferably contains the above polycarbonate resin in an amount of 50% by weight or more.
Further, the polycarbonate resin preferably has an MFR of 1.0 to 20.0 g / 10 min, more preferably 2.0 to 15.0 g / 10 min. Resins in this range are suitable for foaming, and are easily foamed more easily. Further, the polycarbonate resin preferably has an MFR of 1.0 to 15.0 g / 10 minutes, more preferably 1.0 to 14.0 g / 10 minutes, and more preferably 1.0 to 12.0 g / min. 10 minutes is more preferred. The resin in this range can suitably realize the variation rate X of the foam molded article described later.

1-7. Shape of Expanded Particle The shape of the expanded particle is not particularly limited. For example, a spherical shape, a columnar shape, and the like are given. Of these, it is preferable that the shape is as close to spherical as possible. That is, it is preferable that the ratio of the minor axis to the major axis of the expanded particles is as close to 1 as possible.
The expanded particles preferably have an average particle diameter of 1 to 20 mm. The average particle diameter is a value represented by D50 obtained by classification using a low tap sieve shaker.

1-8. Method for Producing Expanded Particles Expanded particles can be obtained by impregnating a resin particle with a blowing agent to obtain expandable particles, and expanding the expandable particles.
1-8-1. Production of Expandable Particles Expandable particles can be obtained by impregnating resin particles made of a polycarbonate resin with a foaming agent.
The resin particles can be obtained by a known method. For example, a polycarbonate resin is melt-kneaded in an extruder and extruded together with other additives as necessary to obtain a strand, and the obtained strand is cut in the air, cut in water, and heated. There is a method of granulating by cutting while cutting. Commercially available resin particles may be used as the resin particles. If necessary, the resin particles may contain other additives in addition to the resin. Other additives include a plasticizer, a flame retardant, a flame retardant auxiliary, an antistatic agent, a spreading agent, a foam regulator, a filler, a coloring agent, a weathering agent, an antioxidant, an antioxidant, and an ultraviolet absorber. , A lubricant, an antifogging agent, and a fragrance.

Next, as a foaming agent impregnated in the resin particles, a known volatile foaming agent or an inorganic foaming agent can be used. Examples of the volatile foaming agent include aliphatic hydrocarbons such as propane, butane, and pentane, aromatic hydrocarbons, alicyclic hydrocarbons, and aliphatic alcohols. Examples of the inorganic foaming agent include carbon dioxide gas, nitrogen gas, air, and inert gas (such as helium and argon). Two or more of these foaming agents may be used in combination. Of these foaming agents, inorganic foaming agents are preferred, and carbon dioxide is more preferred.
The content (impregnation amount) of the blowing agent is preferably 3 to 15 parts by weight based on 100 parts by weight of the polycarbonate resin. If the content of the foaming agent is less than 3 parts by weight, the foaming power may be low, and it may be difficult to favorably foam. If the content exceeds 15 parts by weight, the plasticizing effect becomes large, shrinkage tends to occur at the time of foaming, productivity is deteriorated, and it may be difficult to obtain a desired multiple of foam stably. A more preferable content of the foaming agent is 4 to 12 parts by weight.

Examples of the impregnation method include a wet impregnation method in which resin particles are dispersed in an aqueous system and impregnation is performed by press-fitting a foaming agent while stirring, or a method in which resin particles are charged into a sealable container, and the foaming agent is press-fitted and impregnated. Dry impregnation method (gas-phase impregnation method) without using water specifically. In particular, a dry impregnation method capable of impregnation without using water is preferable. The impregnation pressure, impregnation time and impregnation temperature when impregnating the resin particles with the foaming agent are not particularly limited.
The impregnation pressure is preferably from 0.5 to 10 MPa (gauge pressure) from the viewpoint of performing the impregnation efficiently and obtaining more excellent expanded particles and expanded molded articles. It is more preferable that the pressure be 1 to 4.5 MPa (gauge pressure).

The impregnation time is preferably 0.5 to 200 hours. If the time is less than 0.5 hour, the impregnating amount of the foaming agent into the resin particles is reduced, so that it may be difficult to obtain a sufficient foaming power. If it is longer than 200 hours, productivity may decrease. A more preferred impregnation time is 1 to 100 hours.

The impregnation temperature is preferably from 0 to 60 ° C. When the temperature is lower than 0 ° C., the solubility of the foaming agent in the resin increases, and the foaming agent is impregnated more than necessary. In addition, the diffusivity of the foaming agent in the resin decreases. Therefore, it may be difficult to obtain a sufficient foaming power (primary foaming power) within a desired time. When the temperature is higher than 60 ° C., the solubility of the foaming agent in the resin decreases, and the impregnation amount of the foaming agent decreases. In addition, the diffusivity of the foaming agent in the resin increases. Therefore, it may be difficult to obtain a sufficient foaming power (primary foaming power) within a desired time. A more preferred impregnation temperature is 5 to 50 ° C.

A surface treatment agent such as a binding inhibitor (anti-coalescing agent), an antistatic agent, and a spreading agent may be added to the impregnated material.
The bonding inhibitor plays a role in preventing coalescence of the foamed particles in the foaming step. Here, coalescence means that a plurality of expanded particles are united and integrated. Specific examples of the binding inhibitor include talc, calcium carbonate, aluminum hydroxide and the like.
Examples of the antistatic agent include polyoxyethylene alkylphenol ether and stearic acid monoglyceride.
Examples of the spreading agent include polybutene, polyethylene glycol, and silicone oil.

1-8-2. Production of Expanded Particles As a method of expanding the expandable particles to obtain expanded particles (primary expanded particles), a method of expanding the expandable particles by heating with hot air, a heat medium such as oil, steam (steam), or the like is used. is there. Steam is preferred for stable production.
It is preferable to use a closed pressure-resistant foaming container for the foaming machine at the time of foaming. The steam pressure is preferably 0.10 to 0.80 MPa (gauge pressure), and more preferably 0.25 to 0.45 MPa (gauge pressure). The foaming time may be any time required to obtain a desired foaming multiple. The preferred foaming time is 5 to 180 seconds. If the time exceeds 180 seconds, shrinkage of the foamed particles may start, and a foamed molded product having good physical properties may not be obtained from such foamed particles.
The binding inhibitor may be removed before molding. As a removing method, it is preferable to perform washing using an acidic aqueous solution such as water or hydrochloric acid.

1-8-3. Adjustment of Cell Density X and Average Cell Wall Thickness In the above-mentioned production process of the expanded particles, by adjusting the impregnation conditions (impregnation pressure, impregnation time, impregnation temperature) and primary foaming conditions (expansion pressure, foam time), it is possible to obtain air bubbles. The density X and the average cell wall thickness can be increased or decreased.

1-8-4. Adjustment of bulk factor and average cell diameter In the above-mentioned production process of the foamed particles, by adjusting the impregnation conditions (impregnation pressure, impregnation time, impregnation temperature) and primary foaming conditions (expansion pressure, foaming time), the bulk factor and The average cell diameter can be increased or decreased.

2. Expanded molded article A foamed molded article is obtained from a plurality of expanded particles using a polycarbonate resin as a base resin. Here, the expanded particles are preferably any one selected from the group consisting of the first expanded particles and the second expanded particles.

2-1. Bubble density X
The cell density X is calculated from the foam particles constituting the foam molded article. The cell density X is the same as that of the expanded particles described above, and has the following formula:
Bubble density X = (ρ / D-1) / {(4/3) · π · (C / 100000/2) ³ }
Can be calculated from Here, D is the density of the foam molded article.
Cell density X can be a 1.0 × 10 ⁶ cells / cm ³ or more 1.0 × 10 below ⁸ / cm ^3. The reason for setting the cell density X to the specific range is the same as the reason for the foamed particles. The preferred range and the more preferred range of the cell density X are the same as the respective ranges of the expanded particles.
Further, the preferable range of the average cell diameter C and the density ρ of the polycarbonate resin, the reason for setting the range, the more preferable range, and the further preferable range are the same as those of each of the expanded particles.
The density D of the foam molded article is preferably in the range of 12 to 600 kg / m ³ . If the density D is less than 12 kg / m ³ , the cell membrane becomes thin and the cell membrane breaks during molding, increasing the proportion of open cells, which may lead to deterioration in the strength of the molded body. When the density D is larger than 600 kg / m ³ , the foam film may be thick and the moldability may be reduced. A more preferred density D is 24 to 240 kg / m ³ , and a still more preferred density D is 30 to 120 kg / m ³ .

2-2. Average Cell Wall Thickness The average cell wall thickness can be 1 to 15 μm. The reason for setting the average cell wall thickness in the specific range is the same as the reason for the above-mentioned expanded particles. The preferable range and the more preferable range of the average cell wall thickness are the same as the respective ranges of the expanded particles.

2-3. The value obtained by dividing the average cell diameter of the foamed article by a multiple of the foamed article The value obtained by dividing the average cell diameter of the foamed article by a multiple of the foamed article indicates a value within the range of 2.5 to 12 μm / times. . If the value is less than 2.5 μm / fold, the foam film becomes thin, and the foamed particles shrink due to buckling of the bubbles, and as a result, the mechanical strength of the foamed molded article may be reduced. If the value is more than 12 μm / times, the foam film becomes thick and the moldability decreases, and as a result, the mechanical strength of the foamed molded article may be reduced. The value is preferably from 3.0 to 10.0 μm / fold, more preferably from 3.0 to 6.5 μm / fold.
The multiple is preferably in the range of 2 to 20 times. If the multiple is less than twice, the thickness of the cell membrane may be increased and the moldability may be reduced, and the fusion property between the foamed particles during molding may be reduced. If the multiple is more than 20 times, the cell membrane becomes thin and the cell membrane is broken at the time of molding, and the ratio of open cells increases, which may lead to deterioration of the strength of the molded article. The multiple is preferably 3 to 18 times, more preferably 5 to 16 times.

2-4. Cell Number Density The cell number density X is calculated from the foam particles constituting the foam molded article. The cell number density is calculated by the following formula as in the case of the expanded particles.
Bubble number density = (ρ / D−1) / {(4/3) · π · (C / 100000/2) ³ }
Can be calculated from Here, D is the density of the foam molded article.
It is preferable that the bubble number density X indicates 1.0 × 10 ⁷ to 1.0 × 10 ⁹ cells / cm ³ . When the cell number density is out of the above specific range, the moldability is poor and the mechanical strength may be reduced. The preferable range and the more preferable range of the cell number density are the same as the respective ranges of the expanded particles.
Further, the preferable range of the average cell diameter C and the density ρ of the polycarbonate resin, the reason for setting the range, the more preferable range, and the further preferable range are the same as those of each of the expanded particles.
The density D of the foam molded article is preferably in the range of 12 to 600 kg / m ³ . If the density D is less than 12 kg / m ³ , the cell membrane becomes thin and the cell membrane breaks during molding, increasing the proportion of open cells, which may lead to deterioration in the strength of the molded body. When the density D is larger than 600 kg / m ³ , the thickness of the cell membrane may be increased, and the moldability may be reduced, and the fusion property between the foamed particles during molding may be reduced. The density D is more preferably from 24 to 240 kg / m ³ , even more preferably from 30 to 120 kg / m ³ .
The foam molded article preferably has an average cell wall thickness in the range of 1 to 15 μm. If the average cell wall thickness is less than 1 μm, the moldability during molding, particularly fusion, may be poor. When the average cell wall thickness is larger than 15 μm, it may be difficult to increase the magnification. The average cell wall thickness is more preferably 1 to 10 μm, and further preferably 1 to 5 μm.

2-5. Open cell ratio The open cell ratio is preferably 0 to 50%. If the open cell ratio is larger than 50%, the mechanical strength may be reduced. The open cell rate is more preferably 0 to 40%, further preferably 0 to 30%, and particularly preferably 0 to 25%.

2-6. Foaming factor The foaming factor is preferably in the range of 3 to 30 times. When the multiple is less than three times, the foam film of the foamed particles becomes thick, and the fusion property between the foamed particles during molding may be reduced. When the multiple is more than 30 times, the cell membrane becomes thin, the cell membrane is broken at the time of foaming, and the ratio of open cells increases, which may lead to deterioration in strength as a molded article. The multiple is more preferably 4 to 20 times, and further preferably 4 to 15 times.

2-7. Change rate X
The foamed molded article was measured at the respective temperatures of -40 ° C, 23 ° C, 80 ° C, and 140 ° C to determine the value of the maximum point stress of the four-point bending test, and the maximum point stress of the four-point bending test. When the average value is calculated, the variation rate X of the maximum point stress value of the four-point bending test with respect to the average value in the range of 0 to 50% is shown.
The variation rate X is calculated according to the following procedure when the maximum point stresses in the four-point bending test are A, B, C, and D. First, for A, the following formula:
| Average value of maximum stress in bending test−A | / Average value of maximum stress in bending test × 100
The calculated individual variation rate X _A. Similarly calculated B, individual variation rate _X B also C and D, the _{X C} and _{X D.} Of the four individual fluctuation rates obtained, the one having the largest value is defined as the fluctuation rate X.

The present inventors have found that, when the foamed molded product exhibits this variation rate X, it is possible to provide a foamed molded product in which fluctuations in mechanical strength are suppressed even when the environmental temperature changes. When the variation rate X is out of the range of 0 to 50%, it is difficult to obtain a foam molded article whose mechanical strength changes due to a change in environmental temperature. The variation rate X is preferably in the range of 0 to 45%, and more preferably in the range of 0 to 40%.
For example, the maximum point stress in the bending test at 140 ° C. is preferably 0.5 MPa to 20.0 MPa. If the maximum point stress in the bending test is less than 0.5 MPa, the strength may be insufficient and it may not be possible to withstand an impact or the like. When the maximum point stress in the bending test is larger than 20.0 MPa, it may be easily broken at the time of impact. The maximum point stress in the bending test is more preferably from 0.5 to 10.0 MPa, even more preferably from 0.6 to 5.0 MPa.

2-8. Change rate Y
For the foamed molded article, the four points of the maximum point stress of the bending test at each temperature of −40 ° C., 23 ° C., 80 ° C., and 140 ° C. are divided by the density of the foamed molded article to obtain four points of “bending test”. When calculating the average value of the maximum stress / density of the four points and the maximum stress / density of the four points of the bending test, the four points of the maximum value of the bending test with respect to the average value in the range of 0 to 50% It is preferable to show the rate of change Y of the value of “point stress / density”. By having this variation rate, it is possible to provide a foam molded article that is more resistant to changes in environmental temperature. The fluctuation rate Y is preferably in the range of 0 to 45%, and more preferably in the range of 0 to 40%.
The average value of the "maximum point stress / density of the bending test" of the four points is a combination of the maximum point stress and the density of the four points of the bending test as A and a, B and b, C and c, and D and When d is used, the following formula:
(A / a + B / b + C / c + D / d) / 4
Can be calculated.
The variation rate Y is calculated by the following procedure when the set of the maximum point stress and the density in the four-point bending test is A and a, B and b, C and c, and D and d. First, for A and a, the following formula:
| Average value of “maximum stress / density of bending test” −A / a | / Average value of “maximum stress / density of bending test” × 100
, The individual fluctuation rate Y _Aa is calculated. Similarly, individual fluctuation rates Y _Bb , Y _Cc and Y _Dd are calculated for B and b, C and c, and D and d. Among the four individual fluctuation rates obtained, the one with the largest value is defined as the fluctuation rate Y.
The density is preferably from 30 to 400 kg / m ³ , more preferably from 50 to 300 kg / m ³ .

2-9. Degree of change Z
The foamed molded article exhibits a degree of change Z in which the “maximum point stress of the bending test” at −40 ° C. changes from the “maximum point stress of the bending test” at 23 ° C. within a range of 0 to 0.88. Is preferred. By having this degree of change, it is possible to provide a foam molded article that is more resistant to changes in environmental temperature. The degree of change Z is preferably from 0 to 0.7, and more preferably from 0 to 0.5.
The degree of change Z is calculated by the following equation:
Degree of change Z = [(Maximum point stress of bending test at −40 ° C.) − (Maximum point stress of bending test at 23 ° C.)] ÷ (Maximum point stress of bending test at 23 ° C.)
Can be calculated.
Further, the foamed molded product has a degree of change Z ′ at which the “maximum point stress of the bending test” at 80 ° C. changes within the range of 0 to 0.6 with respect to the “maximum point stress of the bending test” at 23 ° C. Preferably. By having this degree of change, it is possible to provide a foam molded article that is more resistant to changes in environmental temperature. The degree of change Z ′ is preferably from 0 to 0.5, and more preferably from 0 to 0.35.
The degree of change Z ′ is calculated by the following equation:
Degree of change Z ′ = [(Maximum point stress of bending test at 23 ° C.) − (Maximum point stress of bending test at 80 ° C.)] / (Maximum point stress of bending test at 23 ° C.)
Can be calculated.

2-10. Polycarbonate resin As the polycarbonate resin, the same polycarbonate resin as the above-mentioned expanded particles can be used.

2-11. Uses of the foam molded article The foam molded article is not particularly limited, and can take various shapes depending on the use. For example, foam molded articles are used for building materials (such as civil engineering and housing related), parts of transportation equipment such as automobiles, aircraft, railway vehicles, ships, etc., structural members such as windmills and helmets, packing materials, and cores of FRP as composite members. It can take various shapes depending on the use of the material and the like.
From the viewpoint that fluctuations in mechanical strength are suppressed even when the environmental temperature changes, examples of automobile components include components used near the engine, exterior materials, and the like. The automobile parts include, for example, floor panels, roofs, hoods, fenders, undercovers, wheels, steering wheels, containers (housings), hood panels, suspension arms, bumpers, sun visors, trunk lids, luggage boxes, seats , Doors, cowls and the like.

2-12. Method for Producing a Foamed Molded Article A foamed molded article can be obtained, for example, by giving the foamed particles a force for expanding bubbles, and then subjecting the foamed particles to a molding step.
It is preferable that a foaming agent is impregnated in the foamed particles to give a foaming power (secondary foaming power) before producing the foamed molded article.
Examples of the impregnation method include a wet impregnation method in which the foamed particles are dispersed in an aqueous system and impregnated by press-fitting the foaming agent with stirring, or a method in which the foamed particles are charged into a sealable container, and the foaming agent is press-fitted and impregnated. Dry impregnation method (gas-phase impregnation method) without using water specifically. In particular, a dry impregnation method capable of impregnation without using water is preferable. The impregnation pressure, impregnation time and impregnation temperature when impregnating the foaming particles with the foaming agent are not particularly limited.

As the foaming agent to be used, a foaming agent for producing foamed particles, for example, a known volatile foaming agent or an inorganic foaming agent can be used. Examples of the volatile foaming agent include aliphatic hydrocarbons such as propane, butane, and pentane, aromatic hydrocarbons, alicyclic hydrocarbons, and aliphatic alcohols. Examples of the inorganic foaming agent include carbon dioxide gas, nitrogen gas, air, and inert gas (such as helium and argon). Among them, it is preferable to use an inorganic foaming agent. In particular, it is preferable to use one or more of nitrogen gas, air, inert gas (helium, argon), and carbon dioxide gas in combination.
The pressure for applying the internal pressure is desirably a pressure that does not cause the foamed particles to be crushed and within a range that can provide the foaming power. Such a pressure is preferably from 0.1 to 4 MPa (gauge pressure), and more preferably from 0.3 to 3 MPa (gauge pressure). Impregnating the foaming particles with the foaming agent in this manner is referred to as applying internal pressure.

The impregnation time is preferably 0.5 to 200 hours. If the time is less than 0.5 hour, the amount of the foaming agent impregnated into the foamed particles may be too small, and it may be difficult to obtain the necessary secondary foaming power during molding. If it is longer than 200 hours, productivity may decrease. A more preferred impregnation time is 1 to 100 hours.

The impregnation temperature is preferably from 0 to 60 ° C. If the temperature is lower than 0 ° C., it may be difficult to obtain a sufficient secondary foaming power within a desired time. If the temperature is higher than 60 ° C., it may be difficult to obtain a sufficient secondary foaming power within a desired time. A more preferred impregnation temperature is 5 to 50 ° C.

After taking out the foamed particles to which the internal pressure has been applied from the container at the time of impregnation, supplying the foamed particles to a molding space formed in a molding die of a foaming molding machine, by introducing a heating medium, it is possible to carry out in-mold molding to a desired foamed molded product. . Examples of the foam molding machine include an EPS molding machine used for producing a foam molded article from polystyrene resin foam particles and a high-pressure specification molding used for producing a foam molded article from polypropylene resin foam particles. Machine or the like can be used. As the heating medium, if the heating time is prolonged, shrinkage or fusion failure may occur in the foamed particles, and therefore a heating medium capable of giving high energy in a short time is desired. Thus, steam is preferable as such a heating medium. is there.
The pressure of the steam is preferably 0.2 to 1.0 MPa (gauge pressure). Further, the heating time is preferably from 10 to 90 seconds, more preferably from 20 to 80 seconds.
The adjustment of the cell density X and the average cell wall thickness is performed by adjusting the impregnation conditions (impregnation temperature) in the production process of the foamed molded article, in addition to using the foamed particles having the specific cell density X and the average cell wall thickness. , Impregnation time, impregnation pressure) and primary foaming conditions (foaming pressure, foaming time) can increase or decrease the cell density X and the average cell wall thickness.
In addition, the adjustment of the bulk multiple and the average cell diameter is performed by using the expanded particles having the specific bulk multiple and the average cell diameter described above, as well as the impregnation conditions (impregnation temperature, impregnation time, By adjusting the primary foaming conditions (foaming pressure, foaming time), the bulk number and the average cell diameter can be increased or decreased.
Adjustment of the maximum point stress and the density of the bending test is performed by adjusting the impregnation conditions (impregnation temperature, impregnation time, impregnation pressure) and molding conditions (expansion pressure, foaming time) in the production process of the foam molded article. The maximum point stress and density of the bending test can be increased or decreased.

2-13. Reinforced composite A skin material may be laminated and integrated on the surface of the foam molded article to be used as a reinforced composite. When the foamed molded article is a foamed sheet, it is not necessary to be laminated and integrated on both sides of the foamed molded article, and it is sufficient that the skin material is laminated and integrated on at least one of the two surfaces of the foamed molded article. The lamination of the skin material may be determined according to the use of the reinforced composite. Above all, in consideration of the surface hardness and mechanical strength of the reinforced composite, it is preferable that the skin material is laminated and integrated on both surfaces in the thickness direction of the foamed molded product.
The skin material is not particularly limited, and examples thereof include a fiber reinforced plastic, a metal sheet, and a synthetic resin film. Of these, fiber reinforced plastics are preferred. A reinforced composite using fiber reinforced plastic as a skin material is referred to as a fiber reinforced composite.
The reinforcing fibers constituting the fiber-reinforced plastic include inorganic fibers such as glass fiber, carbon fiber, silicon carbide fiber, alumina fiber, Tyranno fiber, basalt fiber, and ceramic fiber; metal fibers such as stainless steel fiber and steel fiber; and aramid. Organic fibers such as fibers, polyethylene fibers, and polyparaphenylenebenzoxazole (PBO) fibers; and boron fibers. The reinforcing fibers may be used alone or in combination of two or more. Among them, carbon fibers, glass fibers, and aramid fibers are preferable, and carbon fibers are more preferable. These reinforcing fibers have excellent mechanical properties despite their light weight.

The reinforcing fiber is preferably used as a reinforcing fiber base processed into a desired shape. Examples of the reinforcing fiber base include a woven fabric, a knitted fabric, and a nonwoven fabric using the reinforcing fiber, and a face material formed by binding (sewing) a fiber bundle (strand) in which reinforcing fibers are aligned in one direction with a thread. . Examples of the weaving method of the woven fabric include plain weave, twill weave, and satin weave. Examples of the yarn include a synthetic resin yarn such as a polyamide resin yarn and a polyester resin yarn, and a stitch yarn such as a glass fiber yarn.
The reinforcing fiber base may be used without laminating only one reinforcing fiber base, or may be used as a laminated reinforcing fiber base by laminating a plurality of reinforcing fiber bases. As the laminated reinforcing fiber base material obtained by laminating a plurality of reinforcing fiber base materials, (1) a plurality of one kind of reinforcing fiber base material is prepared, and a laminated reinforcing fiber base material obtained by laminating these reinforcing fiber base materials; 2) A plurality of types of reinforcing fiber base materials are prepared, a laminated reinforcing fiber base material obtained by stacking these reinforcing fiber base materials, and (3) a fiber bundle (strand) in which reinforcing fibers are aligned in one direction are bound with yarn ( A plurality of reinforced fiber substrates are prepared, and the reinforced fiber substrates are overlapped so that the fiber directions of the fiber bundles are directed in different directions. For example, a laminated reinforced fiber base material integrated (sewed) with the above is used.

The fiber-reinforced plastic is obtained by impregnating a reinforcing fiber with a synthetic resin. The reinforcing fibers are bound and integrated by the impregnated synthetic resin.
The method for impregnating the reinforcing fiber with the synthetic resin is not particularly limited, and examples thereof include (1) a method of immersing the reinforcing fiber in the synthetic resin, and (2) a method of applying the synthetic resin to the reinforcing fiber.
As the synthetic resin to be impregnated into the reinforcing fibers, either a thermoplastic resin or a thermosetting resin can be used, and a thermosetting resin is preferably used. The thermosetting resin to be impregnated into the reinforcing fibers is not particularly limited, and may be an epoxy resin, an unsaturated polyester resin, a phenol resin, a melamine resin, a polyurethane resin, a silicone resin, a maleimide resin, a vinyl ester resin, a cyanate ester resin, or a maleimide. Epoxy resins and vinyl ester resins are preferred because of their excellent heat resistance, shock absorption 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 two or more kinds may be used in combination.

The thermoplastic resin to be impregnated into the reinforcing fibers is not particularly limited, and includes olefin resins, polyester resins, thermoplastic epoxy resins, amide resins, thermoplastic polyurethane resins, sulfide resins, and acrylic resins. Polyester resins and thermoplastic epoxy resins are preferred because they are excellent in adhesiveness to a foamed molded article or adhesiveness between reinforcing fibers constituting a fiber-reinforced plastic. The thermoplastic resin may be used alone, or two or more kinds may be used in combination.
The thermoplastic epoxy resin is a polymer or copolymer of epoxy compounds having a linear structure, or a copolymer of an epoxy compound and a monomer polymerizable with the epoxy compound. And a copolymer having a linear structure. Specifically, as the thermoplastic epoxy resin, for example, bisphenol A type epoxy resin, bisphenol fluorene type epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, cycloaliphatic type epoxy resin, long chain aliphatic type Examples include an epoxy resin, a glycidyl ester type epoxy resin, and a glycidylamine type epoxy resin, and a bisphenol A type epoxy resin and a bisphenol fluorene type epoxy resin are preferable. The thermoplastic epoxy resin may be used alone, or two or more kinds may be used in combination.

Examples of the thermoplastic polyurethane resin include a polymer having a linear structure obtained by polymerizing a diol and a diisocyanate. Examples of the diol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, and 1,4-butanediol. The diols may be used alone or in combination of two or more. Examples of the diisocyanate include an aromatic diisocyanate, an aliphatic diisocyanate, and an alicyclic diisocyanate. The diisocyanates may be used alone or in combination of two or more. The thermoplastic polyurethane resin may be used alone, or two or more kinds may be used in combination.
The content of the synthetic resin in the fiber reinforced plastic is preferably from 20 to 70% by weight. When the content is less than 20% by weight, the binding properties between the reinforcing fibers and the adhesiveness between the fiber-reinforced plastic and the foamed molded article become insufficient, and the mechanical properties of the fiber-reinforced plastic and the mechanical strength of the fiber-reinforced composite are reduced. May not be sufficiently improved. If the content is more than 70% by weight, the mechanical properties of the fiber-reinforced plastic may decrease, and the mechanical strength of the fiber-reinforced composite may not be sufficiently improved. The content is more preferably 30 to 60% by weight.
The thickness of the fiber reinforced plastic is preferably 0.02 to 2 mm, more preferably 0.05 to 1 mm. A fiber reinforced plastic having a thickness within this range is excellent in mechanical properties despite its light weight.
Basis weight of the fiber-reinforced plastics, preferably 50 ~ 4000g / ^{m 2,} more preferably 100 ~ 1000g / ^{m 2.} Fiber reinforced plastics having a basis weight within this range are excellent in mechanical properties despite being lightweight.

Next, a method for producing a reinforced composite will be described. The method for producing a reinforced composite body by laminating and integrating a skin material on the surface of a foamed molded article is not particularly limited. For example, (1) laminating and unifying a skin material on the surface of a foamed molded article via an adhesive. (2) Laminating a fiber-reinforced plastic forming material obtained by impregnating a reinforcing fiber with a thermoplastic resin on the surface of a foamed molded article, and using the thermoplastic resin impregnated in the reinforcing fiber as a binder to form a foamed molded article Method of laminating and integrating a fiber-reinforced plastic forming material as a fiber-reinforced plastic on the surface of (3) Laminating a fiber-reinforced plastic forming material in which uncured thermosetting resin is impregnated into reinforcing fibers on the surface of a foamed molded article And a method of laminating and integrating a fiber-reinforced plastic formed by curing the thermosetting resin with the thermosetting resin impregnated in the reinforcing fibers as a binder, on the surface of the foamed molded article; A heated and softened skin material is disposed on the surface of the foam molded body, and the skin material is deformed along the surface of the foam molded body as necessary by pressing the skin material against the surface of the foam molded body. And a method generally applied to the molding of fiber-reinforced plastics. The method (4) can also be suitably used from the viewpoint that the foamed molded article has excellent mechanical properties such as load resistance in a high-temperature environment.
Examples of the method used for molding the fiber reinforced plastic include an autoclave method, a hand lay-up method, a spray-up method, a PCM (Prepreg Compression Molding) method, a RTM (Resin Transfer Molding) method, and a VaRTM (Vacuum assisted Resin Transfer Molding). ) Method.

The fiber-reinforced composite thus obtained is excellent in heat resistance, mechanical strength, and lightness. Therefore, it can be used in a wide range of applications such as in the field of transportation equipment such as automobiles, aircraft, railway vehicles, and ships, in the field of home appliances, in the field of information terminals, and in the field of furniture.
For example, fiber-reinforced composites include transport equipment components and transport equipment component parts (particularly automobile parts) including structural components that constitute the main body of the transport equipment, windmill blades, robot arms, cushioning materials for helmets, It can be suitably used as a transportation container such as an agricultural product box, a heat insulation and cooling container, a rotor blade of an industrial helicopter, and a component packing material.
According to the present invention, there is provided an automobile component constituted by the fiber-reinforced composite of the present invention. Examples of the automobile component include a floor panel, a roof, a bonnet, a fender, an undercover, a wheel, a steering wheel, Components such as a container (housing), a hood panel, a suspension arm, a bumper, a sun visor, a trunk lid, a luggage box, a seat, a door, and a cowl are included.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. First, methods for measuring various physical properties in Examples will be described below.

[Density of polycarbonate resin]
The density of the polycarbonate-based resin was measured by a method specified in ISO1183-1: 2004 or ASTM D-792.

[Blowing agent impregnation amount]
The foaming agent impregnation amount was a value calculated by the following equation.
Foaming agent impregnation amount (% by weight) = (weight immediately after removal of impregnation−weight before impregnation) / weight before impregnation × 100

[Average particle size]
The average particle diameter was a value represented by D50.
Specifically, using a low tap sieve shaking machine (manufactured by Iida Seisakusho), the sieve openings are 26.5 mm, 22.4 mm, 19.0 mm, 16.0 mm, 13.2 mm, 11.20 mm, 9.20 mm. 50mm, 8.80mm, 6.70mm, 5.66mm, 4.76mm, 4.00mm, 3.35mm, 2.80mm, 2.36mm, 2.00mm, 1.70mm, 1.40mm, 1.18mm, JIS standard sieves of 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 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 was created from the obtained results, and the particle diameter (median diameter) at which the cumulative weight became 50% was defined as the average particle diameter.

[Average cell diameter of expanded particles]
The expanded particles obtained by the primary expansion were taken out, and the center of the cross section substantially divided into two at the center of the expanded particles was photographed at a magnification of 200 to 1200 using a scanning electron microscope. The photographed image was printed on A4 paper. Draw three arbitrary straight lines (length 60 mm) parallel to the vertical and horizontal directions on the expanded particle cross-sectional image. If there are bubbles with extremely large bubble diameters, avoid those bubbles and draw arbitrary straight lines. Three directions were drawn.
In addition, in an arbitrary straight line, as much as possible, air bubbles were prevented from coming into contact only at the contact points. The number of bubbles counted for three arbitrary straight lines in each of the vertical and horizontal directions was arithmetically averaged to obtain the number of bubbles.
The average chord length t of the bubble was calculated from the image magnification by counting the number of bubbles and the number of bubbles by the following equation.
Average chord length t (mm) = 60 / (number of bubbles x image magnification)
The image magnification was obtained by measuring the scale bar on the image to 1/100 mm using a “Digimatic caliper” manufactured by Mitutoyo Corporation, and was calculated by the following equation.
Image magnification = actual measured value of scale bar (mm) / display value of scale bar (mm)
Then, the bubble diameter was calculated by the following equation.
Average bubble diameter C (μm) = (t / 0.616) × 1000

[Average cell diameter of expanded molded article]
A 50 mm long x 50 mm wide x 30 mm thick is cut out from the center of a formed body having a length of 400 mm x a width of 300 mm x a thickness of 30 mm. Was taken. The photographed image was printed on A4 paper. Draw three arbitrary straight lines (length 60 mm) parallel to the vertical and horizontal directions on the cross-sectional image of the foamed molded article. Three are drawn in each direction.
In addition, in an arbitrary straight line, as much as possible, air bubbles were prevented from coming into contact only at the contact points. The number of bubbles counted for three arbitrary straight lines in each of the vertical and horizontal directions was arithmetically averaged to obtain the number of bubbles.
The average chord length t of the bubble was calculated from the image magnification by counting the number of bubbles and the number of bubbles by the following equation.
Average chord length t (mm) = 60 / (number of bubbles x image magnification)
The image magnification was obtained by measuring the scale bar on the image to 1/100 mm using a “Digimatic caliper” manufactured by Mitutoyo Corporation, and was calculated by the following equation.
Image magnification = actual measured value of scale bar (mm) / display value of scale bar (mm)
Then, the average bubble diameter was calculated by the following equation.
Average bubble diameter C (μm) = (t / 0.616) × 1000

[Bulk density and bulk multiple of expanded particles]
About 1000 cm ³ of the foamed particles were filled in a measuring cylinder to a scale of 1000 cm ³ . The graduated cylinder was visually observed from the horizontal direction, and if at least one of the expanded particles reached the scale of 1000 cm ³ , the filling of the expanded particles into the graduated cylinder was completed at that time. Next, the weight of the foamed particles filled in the measuring cylinder was weighed to two significant figures after the decimal point, and the weight was defined as Wg. Then, the bulk density of the foamed particles was determined by the following equation.
Bulk density (kg / m ³ ) = (W / 1000) / [1000 × (0.01) ³ ]
The bulk multiple was a value obtained by integrating the reciprocal of the bulk density with the density (kg / m ³ ) of the polycarbonate resin.

[Apparent density and apparent multiple of expanded particles]
The weight A (g) of about 25 cm ³ of the expanded particles was measured. Subsequently, the wire mesh empty container in which the foamed particles were not spilled with the lid closed was immersed in water, and the weight B (g) of the wire mesh empty container in the state of being immersed in water was measured. Next, after putting all the foamed particles in the wire mesh container, the wire mesh container is immersed in water, and the container is shaken several times to remove bubbles attached to the container and the foam particles. The weight C (g) of the wire mesh container in the state of being immersed in water and the total amount of the foamed particles placed in the wire mesh container was measured. Then, the apparent density D (kg / m ³ ) of the expanded particles was calculated by the following equation.
D = A / (A + (B−C)) × 1000
The apparent multiple was a value obtained by integrating the reciprocal of the apparent density with the density (kg / m ³ ) of the polycarbonate resin.

[Density and foaming multiple of foam molded article]
The density (kg / m ³ ) of the foamed molded article is determined by the weight of a test piece (width 75 mm × length 300 mm × thickness 30 mm) cut out from the foamed molded article (formed and dried at 40 ° C. for 20 hours or more). (A) and volume (b) are each measured so that they each have three or more significant figures, and are determined by the formulas (a) / (b) (condition A) or a foamed molded article (at 50 ° C. after molding). The weight (a) and the volume (b) of a test piece (width 25 mm × length 130 mm × thickness 20 mm) cut out of the sample dried from 5 hours or more) were measured so that each of them became three or more significant figures, and the equation was obtained. It was determined by (a) / (b) (condition B). The measurement was performed at a temperature of 23 ° C.
The foaming multiple was a value obtained by integrating the reciprocal of the density with the density (kg / m ³ ) of the polycarbonate resin.

[Open cell ratio of expanded particles]
A sample cup of "Air comparison hydrometer 1000 type" manufactured by Tokyo Science Co., Ltd. was prepared, and the total weight A (g) of the expanded particles satisfying about 80% of the sample cup was measured. The volume B (cm ³ ) of the whole expanded particles was measured by a 1-1 / 2-1 atmospheric pressure method using an air-comparison hydrometer, and measured with a standard sphere (large 28.96 cm ³ small 8.58 cm ³ ). Corrections were made. Subsequently, the wire mesh empty container in which the foamed particles were not spilled with the lid closed was immersed in water, and the weight C (g) of the wire mesh empty container in the state immersed in water was measured. Next, after putting all the foamed particles in the wire mesh container, the wire mesh container is immersed in water, and the container is shaken several times to remove bubbles attached to the container and the foam particles. The weight D (g) of the wire mesh container in the state of being immersed in water and the total amount of the foamed particles placed in the wire mesh container was measured. Then, the apparent volume E (cm ³ ) of the expanded particles was calculated by the following equation. Based on the apparent volume E (cm ³ ) and the volume B (cm ³ ) of the whole expanded particles, the open cell ratio of the expanded particles was calculated by the following equation.
E = A + (CD)
Open cell ratio (%) = 100 × (EB) / E

[Open cell ratio of foam molded article]
The foam was cut out so as not to have a molding surface on both surfaces of the molded body, and the cut surface was finished with a “FK-4N” pan slicer manufactured by Fujishima Koki Co., Ltd., width 25 mm × length 25 mm × thickness 25 mm Five cubic test pieces were prepared. The outer dimensions of the obtained test piece were measured to 1/100 mm using a "Digimatic caliper" caliper made by Mitutoyo Corporation, and the apparent volume (cm ³ ) was obtained. Next, the volume (cm ³ ) of the test piece was determined by a 1-1 / 2-1 atmospheric pressure method using a “1000 type” air comparison specific gravity meter manufactured by Tokyo Science. The open cell rate (%) was calculated by the following formula, and the average value of the open cell rates of the five test pieces was determined. The test piece was stored in advance in a JIS K7100: 1999 symbol 23/50, second-class environment for 16 hours, and then measured in the same environment. The air comparison type specific gravity meter, was corrected by standard sphere (large 28.96Cm ³ small 8.58cm ^3).
Open cell ratio (%) = (apparent volume−volume measured by air comparison specific gravity meter) / apparent volume × 100

[Average cell wall thickness of expanded particles]
The average cell wall thickness of the expanded particles was calculated as follows. It was calculated from the following equation using the average cell diameter and apparent multiple of the expanded particles obtained by the above measurement method.
Average cell wall thickness (μm) = average cell diameter C (μm) × (1 / (1- (1 / apparent multiple)) ^(1/3) −1)

[Average cell wall thickness of foamed molded article]
The average cell wall thickness of the foam molded article was calculated as follows. It was calculated from the following equation using the average cell diameter and the multiple of the foamed molded article obtained by the above measurement method.
Average cell wall thickness (μm) = average cell diameter C (μm) × (1 / (1- (1 / multiple)) ^(1/3) −1)

[Bending test: Density and maximum point load, stress, displacement, and energy]
The load, stress, displacement, and energy at the maximum point were measured by a method based on JIS K7221-1: 2006 "Hard foamed plastic-Bending test-Part 1: Determination of deflection characteristics". That is, a rectangular parallelepiped test piece having a width of 25 mm, a length of 130 mm and a thickness of 20 mm was cut out from the foamed molded article. For the measurement, a Tensilon universal tester (“UCT-10T” manufactured by Orientec) was used. The bending maximum point stress of the bending strength was calculated using a universal testing machine data processing system ("UTPS-237S Ver, 1.00" manufactured by Soft Brain).
The strip-shaped test piece was placed on a support, and the maximum bending point stress was measured under the conditions of a load cell of 1000 N, a test speed of 10 mm / min, a support jig 5R, and an opening width of 100 mm. The number of test pieces is 5 or more, and the condition is the same after conditioned in a standard atmosphere of second grade for 16 hours under the symbol “23/50” (temperature 23 ° C., relative humidity 50%) of JIS K 7100: 1999. It was measured under a standard atmosphere. After adjusting the condition for 24 hours in a constant temperature bath set to each test temperature of -40 ° C, 80 ° C, and 140 ° C, quickly set it in a jig in the device attached constant temperature bath set to each designated temperature, and after 3 minutes A measurement was made. The arithmetic mean value of the maximum bending point stress of each test piece was defined as the maximum bending point stress of the foam molded article.
The maximum bending point stress per unit density was calculated by dividing the maximum bending point stress by the density of the foam molded article.
In addition, the density (kg / m ³ ) of the foamed molded article was obtained by measuring the weight (a) and the volume (b) of a test piece cut out from the foamed molded article, and calculating the equation (a) / (b).

[Bending test: elastic modulus]
The flexural modulus was measured by a method in accordance with JIS K7221-1: 2006 "Hard foamed plastic-Bending test-Part 1: Determination of deflection characteristics". That is, a rectangular parallelepiped test piece having a width of 25 mm, a length of 130 mm and a thickness of 20 mm was cut out from the foamed molded article. For the measurement, a Tensilon universal tester (“UCT-10T” manufactured by Orientec) was used. The flexural modulus was calculated by the following equation using a universal testing machine data processing system ("UTPS-237S Ver, 1.00" manufactured by Soft Brain). The number of test pieces is 5 or more, and the condition is the same after conditioned in a standard atmosphere of second grade for 16 hours under the symbol “23/50” (temperature 23 ° C., relative humidity 50%) of JIS K 7100: 1999. It was measured under a standard atmosphere. The arithmetic mean value of the compressive modulus of each test piece was defined as the flexural modulus of the foam molded article.
The flexural modulus was calculated by the following equation using the straight line at the beginning of the load-deformation curve.
E = Δσ / Δε
E: Flexural modulus (MPa)
Δσ: difference in stress between two points on a straight line (MPa)
Δε: difference in deformation between the same two points (%)
The flexural modulus per unit density was calculated by dividing the flexural modulus by the density of the foam molded article.

[Compression test: density and 5%, 10%, 25%, and 50% stress]
The 5% compressive stress, the 10% compressive stress, the 25% compressive stress, and the 50% compressive stress of the foamed molded article were measured by the method described in JIS K7220: 2006 "Hard foamed plastics-Determination of compression characteristics". That is, using a Tensilon universal testing machine (“UCT-10T” manufactured by Orientec) and a universal testing machine data processing system (“UTPS-237S Ver, 1.00” manufactured by Soft Brain), the specimen size cross section was 50 mm. The compression strength (5% deformation compression stress, 25% deformation compression stress, compression elastic modulus) was measured at a compression rate of 2.5 mm / min with a size of × 50 mm and a thickness of 25 mm. The number of test pieces is 5 or more, and the condition is the same after conditioned in a standard atmosphere of second grade for 16 hours under the symbol “23/50” (temperature 23 ° C., relative humidity 50%) of JIS K 7100: 1999. The measurement was performed under a standard atmosphere. The arithmetic mean of the compressive strength (5% deformation compressive stress, 10% deformation compressive stress, 25% deformation compressive stress, 50% deformation compressive stress) of each test piece was calculated as the 5% compressive stress, 10% % Compressive stress, 25% compressive stress, and 50% compressive stress.
(5% (10%, 25%, 50%) deformation compressive stress)
The 5% (10%, 25%, 50%) deformation compressive stress was calculated by the following equation. The values in parentheses are the conditions for calculating the 10% deformation compressive stress, 25% deformation compression stress, and 50% deformation compression stress.
σ5 (10, 25, 50) = F5 (10, 25, 50) / A ₀
σ5 (10, 25, 50): 5% (10%, 25%, 50%) deformation compressive stress (MPa)
F5 (10, 25, 50): Force at the time of 5% (10%, 25%, 50%) deformation (N)
A ₀ : initial cross-sectional area of test piece (mm ² )

[Compression test: elastic modulus]
The compression elastic modulus of the foamed molded article was measured by the method described in JIS K7220: 2006 “Hard foamed plastic-Determination of compression characteristics”. That is, using a Tensilon universal testing machine (“UCT-10T” manufactured by Orientec) and a universal testing machine data processing system (“UTPS-237S Ver, 1.00” manufactured by Soft Brain), the specimen size cross section was 50 mm. The compression elastic modulus was calculated by the following formula with a compression speed of 2.5 mm / min at a size of × 50 mm and a thickness of 25 mm. The number of test pieces is 5 or more, and the condition is the same after conditioned in a standard atmosphere of second grade for 16 hours under the symbol “23/50” (temperature 23 ° C., relative humidity 50%) of JIS K 7100: 1999. The measurement was performed under a standard atmosphere. The arithmetic mean value of the compressive modulus of each test piece was defined as the compressive modulus of the foam molded article.
The compression modulus was calculated by the following equation using the straight line at the beginning of the load-deformation curve.
E = Δσ / Δε
E: compression modulus (MPa)
Δσ: difference in stress between two points on a straight line (MPa)
Δε: difference in deformation between the same two points (%)
Further, the compression elastic modulus per unit density was calculated by dividing the compression elastic modulus by the density of the foam molded article.

Example 1a
(Resin particle manufacturing process)
Polycarbonate resin particles (Panlite manufactured by Teijin Limited, L-1250Y, density: 1.2 × 10 ³ kg / m ³ ) were dried at 120 ° C. for 4 hours. The obtained dried product was fed to a single-screw extruder having a diameter of 40 mm at a rate of 10 kg / hr per hour and melt-kneaded at 290 ° C. Subsequently, cooling water of about 10 ° C. was supplied from a die hole (four nozzles having a diameter of 1.5 mm were arranged) of a die (temperature: 290 ° C., inlet side resin pressure: 13 MPa) mounted on the tip of the single screw extruder. The resin particles are extruded into a housed chamber, and the rotary shaft of a rotary blade having four cutting blades is rotated at a rotation speed of 5000 rpm and cut into granules. 4 mm).
(Impregnation step)
After 100 parts by weight of the resin particles were sealed in a pressure vessel and the inside of the pressure vessel was replaced with carbon dioxide gas, carbon dioxide gas was injected under a pressure of 1.5 MPa. It was left still in an environment of 20 ° C., and after 24 hours of impregnation, the pressure inside the pressure vessel was slowly released over 5 minutes. In this way, the resin particles were impregnated with carbon dioxide gas to obtain expandable particles. At this time, the foaming agent impregnation amount was 4.8% by weight.

(Foaming process)
Immediately after depressurization in the impregnation step, the expandable particles are taken out of the pressure vessel, and the impregnated material is foamed with steam in a high-pressure foaming tank while stirring at a foaming temperature of 142 ° C. for 48 seconds using steam. I let it. After foaming, drying was performed with a flash dryer to obtain foamed particles. When the bulk density of the obtained expanded particles was measured by the method described above, it was 109 kg / m ³ (expansion ratio 10.95 times).
(Molding process)
After leaving the obtained foamed particles at room temperature (23 ° C.) for one day, they are sealed in a pressure vessel, and the inside of the pressure vessel is replaced with nitrogen gas. Then, the nitrogen gas is impregnated (gauge pressure) to 1.6 MPa. Pressed. It was left still in an environment of 20 ° C., and pressure curing was performed for 24 hours. After taking out, filling in a molding die of 30 mm x 300 mm x 400 mm, heating with 0.85 MPa water vapor for 40 seconds, and then cooling until the maximum surface pressure of the foamed molded product is reduced to 0.05 MPa. Thus, a foam molded article having a foaming factor of 11.64 times (density of 103 kg / m ³ ) was obtained.

Example 2a
Except that the impregnation pressure was 1.3 MPa, the impregnation amount of the foaming agent was 4.5% by weight, and the foaming time was 60 seconds, in the same manner as in Example 1a, except that the number of bulk times was 11.7 times (bulk density: 103 kg / m ³ ) and a foamed molded article having a foaming multiple of 13.3 times (density of 90 kg / m ³ ) were obtained.
Example 3a
Except that the impregnation pressure was increased to 1.0 MPa, the impregnation amount of the foaming agent was set to 3.9% by weight, and the foaming time was set to 102 seconds, the same as Example 1a, except that the bulk factor was 11.89 times (bulk density: 101 kg / m ³ ) to obtain a foamed molded article having a foaming factor of 7.75 times (density of 155 kg / m ³ ).

Example 4a
Except that the impregnation pressure was increased to 1.0 MPa, the impregnation amount of the foaming agent was set to 4.0% by weight, and the foaming time was set to 59 seconds, the same as in Example 1a, except that the volume ratio was 5.5 times (bulk density: 218 kg / m ³ ) and a foamed molded article having a foaming factor of 4.30 times (density of 279 kg / m ³ ) were obtained.
Example 5a
The impregnation pressure was increased to 1.5 MPa, the impregnation amount of the foaming agent was set to 5.2% by weight, and Panlite Z-2601 (density: 1.2 × 10 ³ kg / m ³ ) manufactured by Teijin Limited was used as a polycarbonate resin. Except that the foaming temperature was set to 145 ° C. and the foaming time was set to 31 seconds, foamed particles having a bulk factor of 10.4 times (bulk density of 116 kg / m ³ ) and a foaming factor of 10.25 times were prepared in the same manner as in Example 1a. A foam molded article (having a density of 117 kg / m ³ ) was obtained.
Example 6a
The impregnation pressure was increased to 1.3 MPa, the impregnation amount of the foaming agent was set to 4.5% by weight, and Panlite Z-2601, manufactured by Teijin Limited, was used as the polycarbonate resin. The foaming temperature was 145 ° C., and the foaming time was 32. Except that the time was changed to seconds, foamed particles having a bulk factor of 9.4 times (bulk density of 128 kg / m ³ ) and foaming factors of 9.64 times (density of 125 kg / m ³ ) were obtained in the same manner as in Example 1a. Was.

Comparative Example 1a
Except that the impregnation pressure was 4.0 MPa, the impregnation amount of the foaming agent was 9.5% by weight, and the foaming time was 32 seconds, the same as in Example 1a, except that the bulk factor was 9.91 times (the bulk density was 121 kg / m ^3). )) And a foamed molded article having a foaming factor of 6.83 times (density of 176 kg / m ³ ).
Comparative Example 2a
Except that the impregnation pressure was 4.0 MPa, the impregnation amount of the foaming agent was 9.5% by weight, and the foaming time was 32 seconds, the same as in Example 1a, except that the number of bulk times was 7.95 times (the bulk density was 151 kg / m2). ³ ) Expanded particles and a foamed molded article having an expansion ratio of 4.65 times (density of 258 kg / m ³ ) were obtained.

Comparative Example 3a
The impregnation pressure was 4.0 MPa, the impregnation amount of the foaming agent was 7.8% by weight, and Panlite Z-2601 manufactured by Teijin Limited was used as the polycarbonate resin. The foaming temperature was 145 ° C., and the foaming time was 23. sec and was 6.4 times the bulk multiples in the same manner as in example 1a except that expanded beads and to obtain a foamed molded article of the expansion ratio 4.62 times (density 260 kg / ^{m 3)} of the (bulk density 188 kg / ^{m 3)} Was.

Average cell diameter C, bulk multiple, bulk density, apparent multiple, apparent density D, cell number density, average cell wall thickness of the primary expanded particles of Examples 1a to 6a and Comparative Examples 1a to 3a, and a foam molded article Tables 1 and 2 show the evaluation of the average cell diameter C, the open cell ratio, the expansion ratio, the density D, the cell density X, the average cell wall thickness, the bending test results, and the compression test results.
Further, FIGS. 1 to 3 show photographs obtained by enlarging the cut surfaces of the expanded particles and expanded molded products of Examples 1a to 6a and Comparative Examples 1a to 3a with a scanning electron microscope at a magnification of 30 to 600 times.

From Tables 1 and 2, it can be seen that a foamed molded article having high mechanical strength can be obtained by setting the cell density X and the average cell wall thickness in the specific ranges. Specifically, when Examples 1a to 4a using the same L1250Y as the polycarbonate resin are compared with Comparative Examples 1a to 2a, the maximum point per unit density in the bending test is higher in the example than in the comparative example. It can be seen that the stress, the elastic modulus, and the elastic modulus per unit density in the compression test are improved. Furthermore, when Examples 5a to 6a using the same Z-2601 as the polycarbonate resin are compared with Comparative Example 3a, the maximum stress and elasticity at the unit density in the bending test are larger in the Example than in the Comparative Example. It can be seen that the modulus and the elastic modulus per unit density in the compression test are improved.
Also, from FIGS. 1 to 3, the foamed molded products of Comparative Examples 1a to 3a have poor appearance due to insufficient fusion between the foamed particles and many gaps between the foamed particles. Thus, it can be seen that the foamed molded articles of Examples 1a to 6a have almost no gap between the foamed particles and have a good appearance.

Example 1b
(Resin particle manufacturing process)
Polycarbonate resin particles (Panlite manufactured by Teijin Limited, L-1250Y, density: 1.20 × 10 ³ kg / m ³ ) were dried at 120 ° C. for 4 hours. The obtained dried product was fed to a single-screw extruder having a diameter of 40 mm at a rate of 10 kg / hr per hour and melt-kneaded at 290 ° C. Subsequently, cooling water of about 10 ° C. was supplied from a die hole (four nozzles having a diameter of 1.5 mm were arranged) of a die (temperature: 290 ° C., inlet side resin pressure: 13 MPa) mounted on the tip of the single screw extruder. The resin particles are extruded into a housed chamber, and the rotary shaft of a rotary blade having four cutting blades is rotated at a rotation speed of 5000 rpm and cut into granules. 4 mm).
(Impregnation step)
After 100 parts by weight of the resin particles were sealed in a pressure vessel and the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was injected into the vessel to an impregnation pressure of 2.0 MPa. It was left still in an environment of 20 ° C., and after 24 hours of impregnation, the pressure inside the pressure vessel was slowly released over 5 minutes. In this way, the resin particles were impregnated with carbon dioxide gas to obtain expandable particles. At this time, the foaming agent impregnation amount was 5.8% by weight.

(Foaming process)
Immediately after the depressurization in the impregnation step, the expandable particles are taken out of the pressure vessel, and the impregnated material is foamed with steam in a high-pressure foaming tank while stirring at a foaming temperature of 142 ° C. for 39 seconds using steam. I let it. After foaming, drying was performed with a flash dryer to obtain foamed particles. When the bulk density of the obtained expanded particles was measured by the method described above, it was 109 kg / m ³ (number of bulk times 11.05 times).
(Molding process)
After leaving the obtained foamed particles at room temperature (23 ° C.) for one day, the container is sealed in a pressure vessel, and the inside of the pressure vessel is replaced with nitrogen gas. Then, the nitrogen gas is impregnated (gauge pressure) to 1.0 MPa. Pressed. It was left still in an environment of 20 ° C., and pressure curing was performed for 24 hours. After taking out, filling into a molding die of 30 mm x 300 mm x 400 mm, heating with steam of 0.85 MPa for 40 seconds, and then cooling until the maximum surface pressure of the foamed molded product is reduced to 0.05 MPa. Thus, a foam molded article having a foaming factor of 11.45 times (density of 105 kg / m ³ ) was obtained.

Example 2b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Impregnation pressure: 1.7 MPa
Foaming agent impregnation amount: 5.6% by weight
Foaming time: 42 seconds Example 3b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Impregnation pressure: 1.5MPa
Foaming agent impregnation amount: 5.0% by weight
Foaming time: 48 seconds

Example 4b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Impregnation pressure: 1.3 MPa
Foaming agent impregnation amount: 4.5% by weight
Foaming time: 61 seconds Example 5b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Impregnation pressure: 2.0MPa
Foaming agent impregnation amount: 5.8% by weight
Foaming temperature: 144 ° C
Foaming time: 22 seconds

Example 6b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Impregnation pressure: 2.0MPa
Foaming agent impregnation amount: 5.6% by weight
Foaming time: 8 seconds Example 7b
Except for the following conditions, expanded particles were obtained in the same manner as in Example 1b.
Polycarbonate resin particles: Panlite Z-2601, manufactured by Teijin Limited (density 1.2 × 10 ³ kg / m ³ )
Impregnation pressure: 2.0MPa
Foaming agent impregnation amount: 5.3% by weight
Foaming temperature: 144 ° C
Foaming time: 21 seconds A foam molded article was obtained in the same manner as in Example 1b, except that nitrogen gas was injected into the molding step up to an impregnation pressure (gauge pressure) of 1.6 MPa.

Example 8b
Except for the following conditions, expanded particles were obtained in the same manner as in Example 1b.
Polycarbonate resin particles: Panlite K-1300Y manufactured by Teijin Limited (density 1.2 × 10 ³ kg / m ³ )
Impregnation pressure: 2.0MPa
Foaming agent impregnation amount: 5.5% by weight
Foaming temperature: 148 ° C
Foaming time: 26 seconds A foam molded article was obtained in the same manner as in Example 1b, except that nitrogen gas was injected into the molding step up to an impregnation pressure (gauge pressure) of 1.6 MPa.
Example 9b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Polycarbonate-based resin particles: Wonderlight PC-110 manufactured by Kibi Industry Co., Ltd. (density: 1.2 × 10 ³ kg / m ³ )
Impregnation pressure: 2.0MPa
Foaming agent impregnation amount: 5.8% by weight
Foaming temperature: 139 ° C Foaming time: 41 seconds

Comparative Example 1b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Impregnation pressure: 4.0MPa
Foaming agent impregnation amount: 9.5% by weight
Foaming time: 8 seconds Comparative Example 2b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Polycarbonate resin particles: Lexan 153 manufactured by Subic (density 1.2 × 10 ³ kg / m ³ )
Impregnation pressure: 4.0MPa
Foaming agent impregnation amount: 9.9% by weight
Foaming time: 10 seconds

Comparative Example 3b
Except for the following conditions, the same procedure as in Example 1b was performed to obtain expanded particles and an expanded molded article.
Impregnation pressure: 1.0 MPa
Foaming agent impregnation amount: 3.5% by weight
Foaming time: 147 seconds

Tables 3 to 6 show various physical properties of the expanded particles and the expanded molded articles of Examples 1b to 9b and Comparative Examples 1b to 3b.
4 to 6 show photographs obtained by magnifying the cut surfaces of the expanded particles and the expanded molded articles of Examples 1b to 9b and Comparative Examples 1b to 3b with a scanning electron microscope at a magnification of 30 to 600 times.

From the above Tables 3 to 6, it can be seen that a foam molded article having high mechanical strength can be obtained by setting the bulk multiple and the average cell diameter to specific ranges.
Also, from FIGS. 4 to 6, the foamed molded products of Comparative Examples 1b to 3b have poor appearance due to insufficient fusion between the foamed particles and many gaps between the foamed particles. Thus, it can be seen that the foamed molded articles of Examples 1b to 9b have almost no gap between the foamed particles and have a good appearance.

Example 1c
(Resin particle manufacturing process)
Polycarbonate resin particles (Panlite manufactured by Teijin Limited, L-1250Y, density: 1.20 × 10 ³ kg / m ³ ) were dried at 120 ° C. for 4 hours. The obtained dried product was fed to a single-screw extruder having a diameter of 40 mm at a rate of 10 kg / hr per hour and melt-kneaded at 290 ° C. Subsequently, cooling water of about 10 ° C. was supplied from a die hole (four nozzles having a diameter of 1.5 mm were arranged) of a die (temperature: 290 ° C., inlet side resin pressure: 13 MPa) mounted on the tip of the single screw extruder. The resin particles are extruded into a housed chamber, and the rotary shaft of a rotary blade having four cutting blades is rotated at a rotation speed of 5000 rpm and cut into granules. 4 mm).
(Impregnation step)
After 100 parts by weight of the resin particles were sealed in a pressure vessel and the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was injected into the vessel to an impregnation pressure of 2.0 MPa. It was left still in an environment of 20 ° C., and after 24 hours of impregnation, the pressure inside the pressure vessel was slowly released over 5 minutes. In this way, the resin particles were impregnated with carbon dioxide gas to obtain expandable particles.

(Foaming process)
Immediately after the depressurization in the impregnation step, the expandable particles are taken out of the pressure vessel, and the impregnated material is foamed with steam in a high-pressure foaming tank while stirring at a foaming temperature of 136 ° C. for 54 seconds using steam. I let it. After foaming, drying was performed with a flash dryer to obtain foamed particles.
(Molding process)
After leaving the obtained foamed particles at room temperature (23 ° C.) for one day, the container is sealed in a pressure vessel, and the inside of the pressure vessel is replaced with nitrogen gas. Then, the nitrogen gas is impregnated (gauge pressure) to 1.0 MPa. Pressed. It was left still in an environment of 20 ° C., and pressure curing was performed for 24 hours. After taking out, filling in a molding die of 30 mm x 300 mm x 400 mm, heating with 0.85 MPa water vapor for 40 seconds, and then cooling until the maximum surface pressure of the foamed molded product is reduced to 0.05 MPa. Thus, a foamed molded article having a foaming factor of about 14 times was obtained.

Example 2c
Expanded particles and a foamed molded article were obtained in the same manner as in Example 1c, except that the foaming time in the foaming step was set to 8 seconds, and the expansion multiple of the foamed molded article was set to about 5 times.
Example 3c Using a polycarbonate-based resin particle (Panlite manufactured by Teijin Limited, Z-2601, density: 1.20 × 10 ³ kg / m ³ ), the foaming temperature in the foaming step was set to 144 ° C., and the foaming time was set to 31 seconds. Was obtained in the same manner as in Example 1c except that the impregnation pressure (gauge pressure) was 1.6 MPa and the expansion multiple of the foamed molded article was about 10 times.
Example 4c
Using polycarbonate resin particles (Lexan, manufactured by SABIC, 153, density 1.20 × 10 ³ kg / m ³ ), the foaming temperature in the foaming step was 141 ° C., the foaming time was 59 seconds, and the foaming multiple of the foamed molded product was about 12 Except that the number was doubled, expanded particles and expanded molded articles were obtained in the same manner as in Example 1c.

Example 5c
Using polycarbonate resin particles (Lexane, manufactured by SABIC, 101R, density: 1.20 × 10 ³ kg / m ³ ), the foaming temperature in the foaming step was 139 ° C., the foaming time was 28 seconds, and the foaming multiple of the foamed article was about 13 Except that the number was doubled, expanded particles and expanded molded articles were obtained in the same manner as in Example 1c.
Example 6c Using polycarbonate resin particles (Panlite, manufactured by Teijin Limited, K-1300Y, density: 1.20 × 10 ³ kg / m ³ ), the foaming temperature in the foaming step was 148 ° C., the foaming time was 26 seconds, and the molding process was performed. Expanded particles and a foamed molded article were obtained in the same manner as in Example 1c, except that the impregnation pressure (gauge pressure) was 1.6 MPa and the expansion multiple of the foamed molded article was about 11 times.
Example 7c Foaming was performed using polycarbonate-based resin particles (Wonderlight, manufactured by Kirimi Industrial Co., Ltd., PC-110, density: 1.20 × 10 ³ kg / m ³ ) at a foaming temperature of 141 ° C. and a foaming time of 41 seconds in a foaming step. Expanded particles and a foamed molded article were obtained in the same manner as in Example 1c except that the foaming multiple of the body was about 12 times.
Example 8c Using a polycarbonate resin particle (manufactured by Teijin Limited, Panlite, L-1250Y, density: 1.20 × 10 ³ kg / m ³ ), the foaming temperature in the foaming step was 136 ° C., and the foaming time was 39 seconds. The expanded particles and expanded molded article were obtained in the same manner as in Example 1c, except that the expansion multiple was set to about 11 times.

Comparative Example 1c
Using polycarbonate resin particles (Lexane, manufactured by SABIC, 153, density 1.20 × 10 ³ kg / m ³ ), the impregnation pressure in the impregnation step was set to 4.0 MPa, and immediately after taking out the expandable particles, 100 parts by weight of the polycarbonate resin was used. On the other hand, except that 0.3 parts by weight of calcium carbonate as a binding inhibitor was mixed, and the foaming time of the foaming step was 120 seconds, and the steam pressure of 0.35 MPa was heated for 60 seconds in the molding step. In the same manner as in Example 1c, expanded particles and an expanded molded article were obtained.

Comparative Example 2c
(1) Preparation of PET Expanded Particles 95% by weight of polyethylene terephthalate (PET) resin (Mitsui Pet SA-135, manufactured by Mitsui Chemicals), 5% by weight of polyethylene naphthalate (PEN) resin (TEONEX TN8050SC, manufactured by Teijin Limited), foam regulator 1.8% by weight (PET-F40-1 manufactured by Terabou) and 0.24% by weight of a cross-linking agent (pyromellitic anhydride manufactured by Daicel) were fed to a single screw extruder having a diameter of 65 mm and an L / D ratio of 35. The mixture was supplied and melt-kneaded at 290 ° C. Subsequently, from the middle of the extruder, a butane composed of 35% by weight of isobutane and 65% by weight of normal butane was melted in a molten state so as to be 0.5 part by weight with respect to 100 parts by weight of the total amount of PET resin and PEN resin. The composition was press-fitted and uniformly dispersed in the resin composition. Thereafter, at the front end of the extruder, the molten resin composition was cooled to 250 ° C., and the resin composition was extruded and foamed from each nozzle of the multi-nozzle mold attached to the front end of the extruder.
(2) Production of foam molded article An in-mold foam molding machine equipped with a mold (male mold and female mold) was prepared. When the male mold and the female mold were clamped, a rectangular parallelepiped cavity having an inner dimension of 300 mm long × 400 mm wide × 30 mm high was formed between the male and female molds.
Then, after filling the foamed particles into the mold with the mold cracking being 3 mm, steam is introduced from the female mold for 30 seconds so that the inside of the cavity becomes 0.05 MPa (gauge pressure), and then from the male mold. Water vapor is introduced for 30 seconds so that the inside of the cavity becomes 0.05 MPa (gauge pressure), and then steam is supplied from both the male and female molds for 30 seconds so that the inside of the cavity becomes 0.1 MPa (gauge pressure). The particles were heated and subjected to secondary foaming, whereby the secondary foamed particles were thermally fused and integrated. After that, after keeping the introduction of steam into the cavity for 900 seconds (heat keeping step), finally, cooling water is supplied into the cavity to cool the foamed molded product in the mold, and then the cavity is cooled. It was opened and the foam molded article was taken out. At this time, the time (molding cycle time) required to obtain a foamed molded article from the step of filling the foamed particles into the mold was 1200 seconds.

Comparative Example 3c
100 parts by weight of the ethylene-propylene random copolymer and 0.10 parts by weight of zinc borate powder (cell regulator) were supplied to an extruder, and were heated and melt-kneaded to form a first molten resin for forming a core layer. At the same time, the ethylene-propylene random copolymer was supplied to another extruder, and was heated and kneaded to form a second molten resin for forming a coating layer.
Next, the first molten resin for forming the core layer and the second molten resin for forming the coating layer are supplied to a co-extrusion die, and the second molten resin is supplied to the first molten resin in the die. The second molten resin was laminated on the first molten resin so as to cover the periphery of the strand.
Next, the laminated molten resin is extruded into a strand shape from a co-extrusion die, cut so as to have a diameter of about 1 mm and a length of about 1.8, and to reduce the average weight per particle to 1 0.8 mg of multilayer resin particles was obtained.
Using the multilayer resin particles, foamed particles were produced as follows.
In a 5 liter autoclave, 100 parts by weight (1000 g) of the multilayer resin particles, 300 parts by weight of water, 0.05 parts by weight of sodium dodecylbenzenesulfonate (surfactant) and 0.3 parts by weight of kaolin (dispersant), Carbon dioxide gas (a foaming agent) was added, the temperature was raised to a temperature lower by 5 ° C. than the foaming temperature while stirring, and the temperature was maintained for 15 minutes. Next, the temperature was raised to the foaming temperature and maintained at the same temperature for 15 minutes. Next, one end of the autoclave was opened, and the contents of the autoclave were released under atmospheric pressure to obtain expanded particles.
During the release of the multilayer resin particles from the autoclave, the release was performed while supplying carbon dioxide gas into the autoclave so that the pressure in the autoclave was maintained at the pressure immediately before the release.
Using the obtained expanded particles, an expanded-particles molded article was formed as follows. Using a small-scale molding machine capable of withstanding a saturated steam pressure of 0.48 MPa (G) as a molding machine, a gap having a molding space of 250 mm × 200 mm × 50 mm without completely closing the mold is provided. (Approximately 5 mm) was filled, then the mold was completely clamped, and the inside of the mold was evacuated with steam pressure, and then 0.42 MPa steam was supplied into the mold for heat molding. After the heat molding, the molded body in the mold was cooled with water until the surface pressure of the molded body became 0.039 MPa, the foamed molded body was taken out of the mold, cured at 80 ° C. for 24 hours, and then cooled to room temperature.

Table 7 shows various physical properties of the foamed molded articles of Examples 1c to 8c and Comparative Examples 1c to 3c. In Table 7, PC means a polycarbonate resin, PET means a polyester resin, and PP means a propylene resin.

From Table 7 above, it can be seen that in the foamed molded products of Examples 1c to 8c, even when the environmental temperature changes, the fluctuation of the mechanical strength is further suppressed. On the other hand, it can be seen that the foamed molded articles of Comparative Examples 1c to 3c fluctuate greatly or melt or deform themselves.
Table 8 shows the calculated values of the stress changes at −40 ° C. and 23 ° C. for the maximum point stress in the bending test. The stress change means [(maximum point stress of bending test at −40 ° C.) − (Maximum point stress of bending test at 23 ° C.)] ÷ (maximum point stress of bending test at 23 ° C.).

Table 9 shows values obtained by calculating stress changes at 80 ° C. and 23 ° C. for the maximum point stress in the bending test. The stress change means [(maximum point stress of bending test at 23 ° C.) − (Maximum point stress of bending test at 80 ° C.)] ÷ (maximum point stress of bending test at 23 ° C.).

From the above Tables 8 and 9, it can be seen that the foamed molded products of Examples 1c to 8c are more suppressed in the fluctuation of the mechanical strength even when the environmental temperature is changed, as compared with the foamed molded products of Comparative Examples 1c to 3c. You can see that there is.

Claims

A foamed particle using a polycarbonate resin as a base resin,
The foam particles,
(I) A bubble density X of 1.0 × 10 6 / cm 3 or more and less than 1.0 × 10 8 / cm 3 [The bubble density X is represented by the following formula:
Bubble density X = (ρ / D-1) / {(4/3) · π · (C / 100000/2) 3 }
(Where C is the average cell diameter (μm), ρ is the density of the polycarbonate resin (kg / m 3 ), and D is the apparent density of the expanded particles (kg / m 3 ).)
(Ii) Expanded particles having an average cell wall thickness of 1 to 15 μm.
The expanded particles, expanded particles of claim 1 which has an apparent density of 20 ~ 640kg / m 3.
2. The foamed particles according to claim 1, wherein the average cell diameter is 20 to 200 μm, and the density of the polycarbonate resin is 1.0 × 10 3 to 1.4 × 10 3 kg / m 3 .
A foamed particle using a polycarbonate resin as a base resin,
The foamed particles are characterized in that the foamed particles have a value in the range of 2.5 to 12 μm / times, when the average cell diameter of the foamed particles is divided by the volume multiple of the foamed particles.
5. The foamed particle according to claim 4, wherein the foamed particle has a cell number density of 1.0 × 10 7 to 1.0 × 10 9 / cm 3 .
5. The foamed particles according to claim 4, wherein the foamed particles have a bulk factor of 2 to 20 times.
The expanded particles according to claim 4, wherein the expanded particles have an open cell ratio of 0 to 10%.
発泡 A foam molded article obtained from the foam particles according to claim 1 or 4.
A foam molded article obtained from a plurality of foam particles having a polycarbonate resin as a base resin,
The foam molded article measures the maximum point stress value of the four-point bending test at each temperature of −40 ° C., 23 ° C., 80 ° C., and 140 ° C., and the maximum point of the four-point bending test A foam molded article characterized in that, when an average value of stress is calculated, a variation rate of a maximum point stress value of the four-point bending test with respect to the average value in a range of 0 to 50% is shown.
10. The foam molded article according to claim 9, wherein the foam molded article has an open cell ratio of 0 to 50%.
10. The foamed molded article according to claim 9, wherein the foamed molded article has a foaming multiple of 3 to 30 times.
The foamed molded article is divided into four values of the maximum point stress of the bending test by the density of the foamed molded article, respectively. When calculating the average value of the “maximum point stress / density of the bending test”, the variation rate of the “maximum point stress / density of the bending test” value of the four points with respect to the average value in the range of 0 to 50% was calculated. The foamed molded article according to claim 9 which shows.
10. The foam molded article according to claim 9, wherein the polycarbonate resin has an MFR of 1.0 to 15.0 g / 10 minutes.
The foam molding according to claim 9, wherein the "maximum point stress of the bending test" at -40 ° C changes within a range of 0 to 0.88 with respect to the "maximum point stress of the bending test" at 23 ° C. body.