THERMALLY EXPANDABLE MICROCAPSULES

Abstract

The present invention provides a thermally expandable microcapsule that has excellent heat resistance and compression resistance and that enables the production of a foam molded article that is less likely to undergo deterioration or appearance defects over a long period of time, as well as a foamable masterbatch and a foam molded article each produced using the thermally expandable microcapsule. Provided is a thermally expandable microcapsule including a shell and a volatile expansion agent as a core agent encapsulated by the shell, the shell containing a black material and a polymer compound.

Claims

1. A thermally expandable microcapsule comprising: a shell; and a volatile expansion agent as a core agent encapsulated by the shell, the shell containing a black material and a polymer compound.

2. The thermally expandable microcapsule according to claim 1, wherein the black material contains at least one selected from the group consisting of a black pigment, a black dye, and a black conductive polymer.

3. The thermally expandable microcapsule according to claim 2, wherein the black pigment is at least one selected from the group consisting of a carbonous black pigment and an oxide black pigment.

4. The thermally expandable microcapsule according to claim 2, wherein the black dye is an organic black dye.

5. The thermally expandable microcapsule according to claim 1, having a black material content of 0.01 to 30% by weight relative to the thermally expandable microcapsule as a whole.

6. The thermally expandable microcapsule according to claim 1, further comprising at least one inorganic compound selected from the group consisting of a Si compound and a Mg compound.

7. The thermally expandable microcapsule according to claim 6, wherein the Si compound contains an oxide, hydroxide, carbonate, or hydrogencarbonate of silicon.

8. The thermally expandable microcapsule according to claim 6, wherein the Mg compound contains an oxide, hydroxide, carbonate, or hydrogencarbonate of magnesium.

9. The thermally expandable microcapsule according to claim 6, having an inorganic compound content of 0.01 to 7% by weight relative to the thermally expandable microcapsule as a whole.

10. The thermally expandable microcapsule according to claim 6, having a weight ratio of the inorganic compound to the black material (inorganic compound/black material) of 0.001 to 400.

11. The thermally expandable microcapsule according to claim 1, wherein the black material is contained within the shell.

12. The thermally expandable microcapsule according to claim 1, having an optical density (OD value) of 0.5 or more.

13. A foamable masterbatch comprising: the thermally expandable microcapsule according to claim 1; and a thermoplastic resin.

14. A foam molded article produced using the thermally expandable microcapsule according to claim 1 or a foamable masterbatch comprising the thermally expandable microcapsule according to claim 1 and a thermoplastic resin.

Description

DESCRIPTION OF EMBODIMENTS

[0142] Embodiments of the present invention are more specifically described in the following with reference to, but not limited to, examples.

EXAMPLE 1

(Preparation of Thermally Expandable Microcapsule)

[0143] Six parts by weight of carbon black [CB] as a black material, 19 parts by weight of colloidal silica (produced by Asahi Denka Co., Ltd., primary average particle size: 20 nm) as an inorganic compound, 0.8 parts by weight of polyvinylpyrrolidone (produced by BASF), and 1.8 parts by weight of 1 N hydrochloric acid were mixed with 250 parts by weight of ion-exchanged water. The mixture was then adjusted to a pH of 3.5 to prepare an aqueous dispersion medium.

[0144] The carbon black used was Aqua-Black #001 (produced by Tokai Carbon Co., Ltd., average particle size: 160 nm, specific surface area: 110 m.sup.2/g, OD value: 3.0).

[0145] Separately, 59.7% by weight of acrylonitrile, 40% by weight of methacrylonitrile, and 0.3% by weight of ethylene glycol dimethacrylate were mixed to prepare a monomer composition in the form of a homogeneous solution. To 97 parts by weight of this monomer composition were added 0.8 parts by weight of a polymerization initiator (2,2′-azobisisobutyronitrile), 0.6 parts by weight of 2,2′-azobis(2,4-dimethylvaleronitrile), and 30 parts by weight of isopentane. They were fed into an autoclave and mixed.

[0146] Thereafter, the resulting mixture was added to the aqueous dispersion medium and suspended to prepare a dispersion.

[0147] The obtained dispersion was mixed and stirred in a homogenizer, fed into a nitrogen-purged pressure polymerizer, and reacted under pressure (0.5 MPa) at 60° C. for 20 hours to give a reaction product. Filtration and water washing of the reaction product were repeated, followed by drying to give thermally expandable microcapsules.

[0148] The obtained thermally expandable microcapsules were added to and dispersed in an embedding resin (Technovit 4000, produced by Kulzer) to a particle content of 3% by weight to prepare a resin with embedded thermally expandable microcapsules. A thin film was prepared with a microtome (EM UC7, produced by LEICA) such that it passed near the centers of the thermally expandable microcapsules dispersed in the embedding resin, and observed with a transmission electron microscope (JEM-2100, produced by JEOL Ltd.) to determine the position of the black material. The black material was present on the particle surfaces.

EXAMPLES 2 AND 3

[0149] Thermally expandable microcapsules were obtained as in Example 1 except that the monomer composition, the black material, and the inorganic compound were mixed according to the formulation shown in Table 1, and that 1.8 parts by weight of 1 N hydrochloric acid was not added.

EXAMPLES 4 TO 11, 13, AND 14

[0150] Thermally expandable microcapsules were obtained as in Example 1 except that the monomer composition, the black material, and the inorganic compound were mixed according to the formulation shown in Table 1.

[0151] In Example 9, titanium black [TB] (titanium black 13M-T, produced by Mitsubishi Materials Electronic Chemicals Co., Ltd., average particle size: 70 nm, specific surface area: 20 m.sup.2/g, OD value: 2.5) was used as the black material.

[0152] In Example 10, iron oxide (BL-100, produced by Titan Kogyo, Ltd., average particle size: 400 nm, specific surface area: 6 m.sup.2/g, OD value: 2.7) was used as the black material.

[0153] In Example 11, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT/PSS) [average particle size: 200 nm, specific surface area: 7 m.sup.2/g, OD value: 1.4] was used as the black material.

[0154] In Example 13, carbon black (Aqua-Black #162, produced by Tokai Carbon Co., Ltd., average particle size: 110 nm, specific surface area: 110 m.sup.2/g, OD value: 3.0) was used as the black material.

[0155] In Example 14, colloidal silica (produced by Asahi Denka Co., Ltd., primary average particle size: 60 nm) was used as the inorganic compound.

EXAMPLE 12

[0156] In a polymerization reaction vessel, an aqueous solution containing 4.7 parts by weight of sodium hydroxide dissolved in 50 parts by weight of ion-exchanged water was gradually added, with stirring, to an aqueous solution containing 8.3 parts by weight of magnesium chloride dissolved in 263 parts by weight of ion-exchanged water, whereby an aqueous dispersion medium containing magnesium hydroxide colloid and having a pH of 9.5 was prepared. To the aqueous dispersion medium containing the magnesium hydroxide colloid was added 3 parts by weight of a carboxylic acid-modified PVA (weight average molecular weight 6,000) to prepare an aqueous dispersion medium containing the magnesium hydroxide colloid and the carboxylic acid-modified PVA. To the prepared aqueous dispersion medium was added 5 parts by weight of carbon black (Aqua-Black #001, produced by Tokai Carbon Co., Ltd.) as a black material (pH 9.5).

[0157] Subsequently, 0.8 parts by weight of a polymerization initiator (2,2′-azobisisobutyronitrile), 0.6 parts by weight of 2,2′-azobis(2,4-dimethylvaleronitrile), and 30 parts by weight of isopentane were added to 97 parts by weight of a monomer composition of the formulation shown in Table 1 to prepare an oily mixture liquid. This oily mixture liquid was added to the aqueous dispersion medium to prepare a dispersion. The obtained dispersion was mixed and stirred in a homogenizer, fed into a nitrogen-purged pressure polymerizer (20 L), and reacted under pressure (0.5 MPa) at 60° C. for 20 hours to give a reaction product. Filtration and water washing of the reaction product were repeated, followed by drying to give thermally expandable microcapsules.

EXAMPLE 15

[0158] Twenty-five parts by weight of colloidal silica (produced by Asahi Denka Co., Ltd., primary average particle size: 20 nm) as an inorganic compound and 0.8 parts by weight of polyvinylpyrrolidone (produced by BASF) were mixed with 250 parts by weight of ion-exchanged water to prepare an aqueous dispersion medium.

[0159] Separately, 20% by weight of acrylonitrile, 30% by weight of methacrylonitrile, 20% by weight of methyl methacrylate, and 30% by weight of methacrylic acid were mixed to prepare a monomer composition in the form of a homogeneous solution. To 97 parts by weight of this monomer composition were added 0.0026 parts by weight of an amine salt of polyether ester acid (DISPARLON-234, produced by Kusumoto Chemicals, Ltd.) as an additive and 0.013 parts by weight of carbon black as a black material, and they were fed into an autoclave. Further, 0.8 parts by weight of a polymerization initiator (2,2′-azobisisobutyronitrile), 0.6 parts by weight of 2,2′-azobis(2,4-dimethylvaleronitrile), 20 parts by weight of isopentane, and 10 parts by weight of isooctane were added and mixed in the autoclave.

[0160] The carbon black used was produced by Mitsubishi Chemical Corporation (MA100, primary average particle size 24 nm, specific surface area 110 m.sup.2/g).

[0161] Thereafter, the resulting mixture was added to the aqueous dispersion medium and suspended to prepare a dispersion.

[0162] The obtained dispersion was stirred in a homogenizer, fed into a nitrogen-purged pressure polymerizer, and reacted under pressure (0.5 MPa) at 60° C. for 20 hours to give a reaction product. Filtration and water washing of the reaction product were repeated, followed by drying to give thermally expandable microcapsules.

[0163] The obtained thermally expandable microcapsules were added to an embedding resin (Technovit 4000, produced by Kulzer) to a particle content of 3% by weight and dispersed to prepare a resin with embedded thermally expandable microcapsules. A thin film was prepared with a microtome (EM UC7, produced by LEICA) such that it passed near the centers of the thermally expandable microcapsules dispersed in the embedding resin, and observed with a transmission electron microscope (JEM-2100, produced by JEOL Ltd.) to determine the position of the black material. The black material was present within the shells.

EXAMPLES 16 TO 20

[0164] Thermally expandable microcapsules were obtained as in Example 15 except that the black material and the additive were mixed in accordance with the formulation shown in Table 2.

EXAMPLES 21 TO 24 AND 26

[0165] Thermally expandable microcapsules were obtained as in Example 18 except that the monomer composition, the black material, and the additive were mixed in accordance with the formulation shown in Table 2.

[0166] In Example 21, carbon black (#2600, produced by Mitsubishi Chemical Corporation, primary average particle size 13 nm, specific surface area 370 m.sup.2/g) was used as the black material.

[0167] In Example 22, carbon black (#52, produced by Mitsubishi Chemical Corporation, primary average particle size 27 nm, specific surface area 88 m.sup.2/g) was used as the black material.

[0168] In Example 23, carbon black (#33, produced by Mitsubishi Chemical Corporation, primary average particle size 30 nm, specific surface area 74 m.sup.2/g) was used as the black material.

[0169] In Example 24, 2.4 parts by weight of Floren DOPA-15BHFS (produced by Kyoeisha Chemical Co., Ltd.) was used as the additive.

[0170] In Example 26, 3.9 parts by weight of a black dye (ChuoBrack F5, trade name Solvent Black 7, produced by Chuo Synthetic Chemical Co., Ltd.) was used as the black material.

EXAMPLE 25

[0171] Thermally expandable microcapsules were obtained as in Example 18 except that the monomer composition, the black material, and the inorganic compound were mixed in accordance with the formulation shown in Table 2, and that 1.8 parts by weight of 1 N hydrochloric acid was added.

COMPARATIVE EXAMPLE 1

[0172] Thermally expandable microcapsules were obtained as in Example 1 except that no black material was added.

COMPARATIVE EXAMPLES 2 AND 3

[0173] Thermally expandable microcapsules were obtained as in Comparative Example 1 except that the monomer composition and the inorganic compound were mixed in accordance with the formulation shown in Table 2, and that 1.8 parts by weight of 1 N hydrochloric acid was not added.

(Evaluation Methods)

[0174] The properties of the obtained thermally expandable microcapsules were evaluated by the following methods. Tables 1 and 2 show the results.

(1) Evaluation of Thermally Expandable Microcapsules

(1-1) Measurement of Volume Average Particle Size

[0175] The volume average particle size of the obtained thermally expandable microcapsules was measured using a laser diffraction/scattering particle size distribution analyzer (LS 13 320, produced by Beckman Coulter).

(1-2) Measurement of Optical Density (OD Value)

[0176] The obtained thermally expandable microcapsules were mixed with an acrylic resin (DPE-6A, dipentaerythritol hexaacrylate, produced by Kyoeisha Chemical Co., Ltd.) at 1:1 to prepare a measurement sample. The measurement sample was applied to a glass substrate (10 cm×10 cm) by spin coating to a dried film thickness of 50 μm, and dried in an oven at 70° C. for 15 minutes to prepare a coating film. The optical density (OD value) of the coating film was measured with a Macbeth densitometer (X-Rite 361T, produced by Sakata Inx Eng. Co., Ltd.). The OD value represents light-shielding properties. A greater OD value indicates that a better foam molded article with higher light-shielding properties can be obtained.

(1-3) Heat Resistance

[0177] A small amount of the thermally expandable microcapsules were spread on a stage of a heat-foaming microscope (produced by Japan High Tech Co., Ltd.). While the microcapsules were heated at 5° C./min, the expansion behavior was observed until 280° C. With the diameter of an unexpanded thermally expandable microcapsule taken as 1 time, the expansion ratio D220 at 220° C. was determined and evaluated in accordance with the following criteria. [0178] less than 3 times: x (poor) [0179] 3 times or more but less than 4 times: ∘ (acceptable) [0180] 4 times or more but less than 5 times: ∘∘ (good) [0181] 5 times or more: ∘∘∘ (very good)

(1-4) Durability

[0182] The expansion behavior was observed using a heat-foaming microscope (produced by Japan High Tech Co., Ltd.) under the same conditions as the heat resistance evaluation. The temperature width (AT) in which the expansion ratio is 2 times or more was determined and evaluated in accordance with the following criteria. [0183] less than 40° C.: x (poor) [0184] 40° C. or more but less than 50° C.: ∘ (acceptable) [0185] 50° C. or more but less than 60° C.: ∘∘ (good) [0186] 60° C. or more: ∘∘∘ (very good)

(1-5) Compression Resistance

[0187] The thermally expandable microcapsules were expanded by heating to a heating temperature of 180° C. at a temperature increase rate of 30° C./min at a load of 0.01 mN using a thermomechanical analyzer (TMA) (TMA2940, produced by TA Instruments). The expansion displacement at this time was taken as 100%. Thereafter, the rate of decrease in expansion displacement when a load was increased to 0.1 mN was measured and evaluated in accordance with the following criteria. [0188] less than 30%; ∘∘∘∘ (Excellent) [0189] 30% or more but less than 50%: ∘∘∘ (very good) [0190] 50% or more but less than 60%: ∘∘ (good) [0191] 60% or more but less than 70%: ∘ (acceptable) [0192] 70% or more: x (poor)

(1-6) Foaming Starting Temperature, Maximum Displacement, and Maximum Foaming Temperature

[0193] The foaming starting temperature (Ts), the maximum displacement (Dmax), and the maximum foaming temperature (Tmax) were measured with a thermomechanical analyzer (TMA) (TMA2940, produced by TA Instruments). Specifically, 25 μg of a sample was placed in an aluminum container having a diameter of 7 mm and a depth of 1 mm and heated at a temperature increase rate of 5° C./min from 80° C. to 220° C. with a force of 0.1 N applied from above. The displacement was measured in the perpendicular direction of a measuring terminal. The temperature at which the displacement began to increase was defined as the foaming starting temperature. The maximum value of the displacement was defined as the maximum displacement. The temperature at which the maximum displacement was obtained was defined as the maximum foaming temperature.

(1-7) Measurement of Ash Content

[0194] The obtained thermally expandable microcapsules were weighed (weight: A parts by weight) and put in a crucible for ash content measurement. The microcapsules were heated with an electric heater at 750° C. for 180 minutes and turned into ash. The obtained ash was weighed (weight: B parts by weight). From the obtained A parts by weight and B parts by weight, the ash content C (% by weight) was calculated using the following equation.

C (% by weight)=(B/A)×100

(1-8) Measurement of Black Material Content

[0195] Using a thermogravimetry-differential thermal analyzer (TA7200, produced by Hitachi High-Tech Science Corporation), 1.0 mg of the obtained thermally expandable microcapsules were heated in a nitrogen atmosphere to 600° C. at 10° C./min, held for 10 minutes, cooled to 400° C. at 10° C./min, and held for 10 minutes. The atmosphere was then changed to the air. The thermally expandable microcapsules were heated in the air to 1,000° C. and held for 10 minutes at 1,000° C., and the weight loss from 400° C. to 1,000° C. was measured. The weight loss was used as the high-temperature combustible content.

[0196] Separately, the high-temperature combustible content of thermally expandable microcapsules containing the same components but no black material was measured. The difference between the high-temperature combustible content of the thermally expandable microcapsules containing a black material and the high-temperature combustible content of the thermally expandable microcapsules containing no black material was calculated as the black material content.

(2) Evaluation of Foam Molded Article

(2-1) Evaluation of Appearance (White Spots)

[Preparation of Foam Molded Article (Examples 1, 4, 7 to 14, and 25 and Comparative Example 1)]

[0197] Five grams of the thermally expandable microcapsules obtained in one of Examples 1, 4, 7 to 14, and 25 and Comparative Example 1, 193 g of an SBS resin (TR-1600, produced by JSR Corporation), and 2 g of a black pigment (PBF-640, produced by Resino Color Industry Co., Ltd.) were weighed and mixed in a cup. The mixture was formed into a rolled sheet using an 8-inch roll mill (191-TM, produced by Yasuda Seiki Seisakusho, Ltd.) at 130° C. This rolled sheet was cut and heated with a press machine (PA-40E/40C, produced by Kodaira Seisakusho Co., Ltd.) at 170° C. to prepare a foam molded article.

[Preparation of Foam Molded Article (Examples 2, 3, 5, 6, 15 to 24, and 26 and Comparative Examples 2 and 3)]

[0198] Five grams of the thermally expandable microcapsules obtained in one of Examples 2, 3, 5, 6, 15 to 24, and 26 and Comparative Examples 2 and 3 and 195 g of a TPV resin (elastomer 7030BS, produced by Mitsui Chemicals, Inc.) were weighed and mixed in a cup. The mixture was formed into a rolled sheet using an 8-inch roll mill (191-TM, produced by Yasuda Seiki Seisakusho, Ltd.) at 110° C. This rolled sheet was cut and heated with a press machine (PA-40E/40C, produced by Kodaira Seisakusho Co., Ltd.) at 205° C. to prepare a foam molded article.

[Evaluation of Appearance (White Spots)]

[0199] The number of white spots was counted on the surface (1 mm square) of each of the foam molded articles using an optical microscope and evaluated in accordance with the following criteria. [0200] less than 10: ∘∘∘ (very good) [0201] 10 or more but less than 40: ∘∘ (good) [0202] 40 or more but less than 70: ∘ (acceptable) [0203] 70 or more: x (poor)

(2-2) Evaluation of Appearance (Color Difference)

[0204] The L*, a*, b* values were measured using a chroma meter (CM-26dG, produced by Konica Minolta, Inc.) at randomly selected five sites on each of the foam molded article samples. The average of the color difference from a base resin to which no particle was added, ΔE*ab=√((ΔL*){circumflex over ( )}2+(Δa*){circumflex over ( )}2(Δb*){circumflex over ( )}2), was calculated and evaluated in accordance with the following criteria. [0205] less than 1.5: ∘∘∘ (very good) [0206] 1.5 or more but less than 2.0: ∘∘ (good) [0207] 2.0 or more but less than 2.5: ∘ (acceptable) [0208] 2.5 or more but less than 3.0: Δ (fair) [0209] 3.0 or more: x (poor)

TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 Black Type CB CB CB CB CB CB CB CB material (aqueous Average particle size (nm) 160 160 160 160 160 160 160 160 dispersion) Addition amount (parts by 1.2 1.2 1.2 0.04 3.8 8.6 0.12 6 weight) [black material only] Inorganic Type Si Si Si Si Si Si Si Si compound Primary average particle 20 20 20 20 20 20 20 20 size (nm) Addition amount (parts by 3.8 3.8 3.8 8.6 1.2 0.04 7.6 3.8 weight) [inorganic compound only] Monomer Nitrile Acrylonitrile 59.7 20 19.48 59.7 59.7 59.7 59.7 59.7 composition monomer Methacrylonitrile 40 30 29.22 40 40 40 40 40 Carboxy Methacrylic 0 30 30 0 0 0 0 0 group- acid containing monomer Crosslinkable Ethylene glycol 0.3 0 0.3 0.3 0.3 0.3 0.3 0.3 monomer dimethacrylate Different Methyl 0 20 20 0 0 0 0 0 monomer methacrylate Thermosetting Bisphenol A 0 0 1 0 0 0 0 0 resin epoxy resin Black Type — — — — — — — — material Average particle size (nm) — — — — — — — — (Hydrophobic) Addition amount (parts by — — — — — — — — weight) [black material only] Additive (dispersant for black material) — — — — — — — — Volatile expansion Isopentane 30 30 30 30 30 30 30 30 agent Isooctane 0 0 0 0 0 0 0 0 Production method Aqueous 3.5 8 8 3.5 3.5 3.5 3.5 3.5 dispersion medium pH Amount of black material fed (% by weight) 1 1 1 0.03 3 6.8 0.1 4.7 Inorganic compound content (% by weight) [B]* 3 3 3 6.8 1 0.03 6 3 Black material content (% by weight) [A]* 0.51 0.58 0.59 0.01 2.43 5.07 0.08 4.01 High-temperature combustible content 5.39 5.46 5.47 4.89 7.31 9.95 4.96 8.89 (% by weight) Position of black material Particle Particle Particle Particle Particle Particle Particle Particle surface surface surface surface surface surface surface surface Evaluation Volume average particle size (μm) 26.8 26.5 26.6 26.3 26.7 26.6 26.8 26.7 Optical density (OD value) 1.6 1.6 1.6 0.5 2.2 2.5 0.6 2.4 Heat Measurement 3.4 4.3 4.6 3 3.5 3.8 3.1 3.2 resistance value Evaluation ∘ ∘∘ ∘∘ ∘ ∘ ∘ ∘ ∘ Durability Measurement 52 55 94 42 54 56 42 44 value Evaluation ∘∘ ∘∘ ∘∘∘ ∘ ∘∘ ∘∘ ∘ ∘ Compression Measurement 58 47 27 69 48 54 69 59 resistance value Evaluation ∘∘ ∘∘∘ ∘∘∘∘ ∘ ∘∘∘ ∘∘ ∘ ∘∘ Ts Measurement 137 160 155 137 137 137 137 137 value [° C.] Tmax Measurement 186 211 214 177 192 194 178 182 value [° C.] Dmax Measurement 891 1013 1045 863 828 784 863 863 value [μm] Ash content Measurement 3.2 3.2 3.2 6.8 1.2 0.07 6 3 value [% by weight] Appearance Measurement 6 3 2 65 2 1 58 31 (white spots) value Evaluation ∘∘∘ ∘∘∘ ∘∘∘ ∘ ∘∘∘ ∘∘∘ ∘ ∘∘ Appearance Measurement 1.67 1.7 1.71 2.9 1.75 1.31 2.44 1.43 (ΔE*ab value) value Evaluation ∘∘ ∘∘ ∘∘ Δ ∘∘ ∘∘∘ ∘ ∘∘∘ Example 9 10 11 12 13 14 Black Type TB Iron PEDOT CB CB CB material oxide (aqueous Average particle size (nm) 70 400 200 160 110 160 dispersion) Addition amount (parts by 1.2 1.2 1.2 1.2 1.2 1.2 weight) [black material only] Inorganic Type Si Si Si Mg Si Si compound Primary average particle 20 20 20 20 20 60 size (nm) Addition amount (parts by 3.8 3.8 3.8 2.6 3.8 3.8 weight) [inorganic compound only] Monomer Nitrile Acrylonitrile 59.7 59.7 59.7 59.7 59.7 59.7 composition monomer Methacrylonitrile 40 40 40 40 40 40 Carboxy Methacrylic 0 0 0 0 0 0 group- acid containing monomer Crosslinkable Ethylene glycol 0.3 0.3 0.3 0.3 0.3 0.3 monomer dimethacrylate Different Methyl 0 0 0 0 0 0 monomer methacrylate Thermosetting Bisphenol A 0 0 0 0 0 0 resin epoxy resin Black Type — — — — — — material Average particle size (nm) — — — — — — (Hydrophobic) Addition amount (parts by — — — — — — weight) [black material only] Additive (dispersant for black material) — — — — — — Volatile expansion Isopentane 30 30 30 30 30 30 agent Isooctane 0 0 0 0 0 0 Production method Aqueous 3.5 3.5 3.5 9.5 3.5 3.5 dispersion medium pH Amount of black material fed (% by weight) 1 1 1 1 1 1 Inorganic compound content (% by weight) [B]* 3 3 3 2 3 3 Black material content (% by weight) [A]* 0.54 0.51 0.54 0.55 0.44 0.49 High-temperature combustible content 5.42 5.39 5.42 5.43 5.32 5.37 (% by weight) Position of black material Particle Particle Particle Particle Particle Particle surface surface surface surface surface surface Evaluation Volume average particle size (μm) 26.9 26.5 26.7 26.4 26.5 26.7 Optical density (OD value) 1.3 1.4 1 1.6 1.6 1.6 Heat Measurement 3.2 3.4 3 3.4 3.5 3.4 resistance value Evaluation ∘ ∘ ∘ ∘ ∘ ∘ Durability Measurement 42 50 42 52 54 52 value Evaluation ∘ ∘∘ ∘ ∘∘ ∘∘ ∘∘ Compression Measurement 67 69 69 59 57 58 resistance value Evaluation ∘ ∘ ∘ ∘∘ ∘∘ ∘∘ Ts Measurement 137 137 137 137 137 137 value [° C.] Tmax Measurement 179 185 177 178 189 186 value [° C.] Dmax Measurement 861 888 861 873 906 891 value [μm] Ash content Measurement 3.2 4.1 3.1 1.9 3.2 3.2 value [% by weight] Appearance Measurement 10 6 16 6 3 6 (white spots) value Evaluation ∘∘ ∘∘∘ ∘∘ ∘∘∘ ∘∘∘ ∘∘∘ Appearance Measurement 1.92 1.66 1.98 1.74 1.69 1.73 (ΔE*ab value) value Evaluation ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ *the content relative to the amount of thermally expandable microcapsules

TABLE-US-00002 TABLE 2 Example 15 16 17 18 19 20 21 22 Black Type — — — — — — — — material Average particle size (nm) — — — — — — — — (aqueous Addition amount (parts by — — — — — — — — dispersion) weight) [black material only] Inorganic Type Si Si Si Si Si Si Si Si compound Primary average particle 20 20 20 20 20 20 20 20 size (nm) Addition amount (parts by 5 5 5 5 5 5 5 5 weight) [inorganic compound only] Monomer Nitrile Acrylonitrile 20 20 20 20 20 20 20 20 composition monomer Methacrylonitrile 30 30 30 30 30 30 30 30 Carboxy Methacrylic 30 30 30 30 30 30 30 30 group- acid containing monomer Crosslinkable Ethylene glycol 0 0 0 0 0 0 0 0 monomer dimethacrylate Different Methyl 20 20 20 20 20 20 20 20 monomer methacrylate Thermosetting Bisphenol A 0 0 0 0 0 0 0 0 resin epoxy resin Black material Type CB CB CB CB CB CB CB CB (Hydrophobic) Average particle size (nm) 150 150 150 150 150 150 80 200 Addition amount (parts by 0.013 0.13 1.3 3.8 6.4 12.7 3.8 3.8 weight) [black material only] Additive (dispersant for black material) 0.0026 0.026 0.25 0.76 127 2.54 0.76 0.76 Volatile expansion Isopentane 20 20 20 20 20 20 20 20 agent Isooctane 10 10 10 10 10 10 10 10 Production method Aqueous 8 8 8 8 8 8 8 8 dispersion medium pH Amount of black material fed (% by weight) 0.01 0.1 1 3 5 10 3 3 Inorganic compound content (% by weight) [B]* 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 Black material content (% by weight) [A]* 0.01 0.09 0.96 3.04 5.02 9.98 3.06 3.01 High-temperature combustible content 4.89 4.97 5.84 7.92 9.90 14.86 7.94 7.89 (% by weight) Position of black material Within Within Within Within Within Within Within Within shell shell shell shell shell shell shell shell Evaluation Volume average particle 26.5 26.5 26.7 26.4 26.9 27.0 26.8 26.5 size (μm) Optical density (OD value) 0.5 0.6 1.4 2.2 2.4 3.4 2.5 2.2 Heat Measurement 4.3 4.4 4.2 4.3 4.6 4.5 4.3 4.2 resistance value Evaluation ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ Durability Measurement 54 55 60 62 61 62 63 61 value Evaluation ∘∘ ∘∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ Compression Measurement 46 48 30 29 28 27 28 29 resistance value Evaluation ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘∘ ∘∘∘∘ ∘∘∘∘ ∘∘∘∘ ∘∘∘∘ Ts Measurement 164 165 163 168 164 160 169 166 value [° C.] Tmax Measurement 215 214 213 215 212 210 216 214 value [° C.] Dmax Measurement 870 768 720 815 725 637 974 912 value [μm] Ash content Measurement 4 4.1 4.3 4.3 4.5 4.6 42 4.3 value [% by weight] Appearance Measurement 63 52 4 3 2 2 2 3 (white spots) value Evaluation ∘ ∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ Appearance Measurement 2.89 2.32 1.98 1.45 1.32 0.8 1.24 1.42 (AE*ab value) value Evaluation Δ ∘∘ ∘∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ Comparative Example Example 23 24 25 26 1 2 3 Black Type — — — — — — — material Average particle size (nm) — — — — — — — (aqueous Addition amount (parts by — — — — — — — dispersion) weight) [black material only] Inorganic Type Si Si Si Si Si Si Si compound Primary average particle 20 20 20 20 20 20 20 size (nm) Addition amount (parts by 5 5 5 5 5 5 5 weight) [inorganic compound only] Monomer Nitrile Acrylonitrile 20 20 55 20 59.7 20 19.48 composition monomer Methacrylonitrile 30 30 35 30 40 30 29.22 Carboxy Methacrylic 30 30 0 30 0 30 30 group- acid containing monomer Crosslinkable Ethylene glycol 0 0 5 0 0.3 0 0.3 monomer dimethacrylate Different Methyl 20 20 5 20 0 20 20 monomer methacrylate Thermosetting Bisphenol A 0 0 0 0 0 0 1 resin epoxy resin Black material Type CB CB CB Black — — — (Hydrophobic) dye Average particle size (nm) 350 150 150 — — — — Addition amount (parts by 3.8 3.8 3.8 3.8 — — — weight) [black material only] Additive (dispersant for black material) 0.76 0.76 0.76 — — — — Volatile expansion Isopentane 20 20 20 20 30 20 30 agent Isooctane 10 10 10 10 0 10 0 Production method Aqueous 8 8 3.5 8 3.5 8 8 dispersion medium pH Amount of black material fed (% by weight) 3 3 3 3 — — — Inorganic compound content (% by weight) [B]* 3.8 3.8 3.8 3.8 3.8 3.8 3.8 Black material content (% by weight) [A]* 2.97 2.99 2.98 — 0 0 0 High-temperature combustible content 7.85 7.87 7.86 — 4.87 4.88 4.88 (% by weight) Position of black material Within Core- Within Within — — — shell shell shell shell interface Evaluation Volume average particle 26.7 26.6 25.9 26.3 26.4 26.5 26.8 size (μm) Optical density (OD value) 2 2.2 2.2 2 0.1 0.1 0.1 Heat Measurement 4.5 4.2 3.3 4.3 2.4 3.8 4.2 resistance value Evaluation ∘∘ ∘∘ ∘ ∘∘ x ∘ ∘∘ Durability Measurement 60 62 43 61 22 28 58 value Evaluation ∘∘∘ ∘∘∘ ∘ ∘∘ x x ∘∘ Compression Measurement 29 28 65 48 99 84 72 resistance value Evaluation ∘∘∘∘ ∘∘∘∘ ∘ ∘∘∘ x x x Ts Measurement 164 163 140 167 133 160 150 value [° C.] Tmax Measurement 213 212 178 215 176 212 204 value [° C.] Dmax Measurement 856 1100 978 885 861 824 935 value [μm] Ash content Measurement 4.1 42 4.1 4 4 4 4 value [% by weight] Appearance Measurement 4 3 2 5 95 83 73 (white spots) value Evaluation ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ x x x Appearance Measurement 1.49 1.46 1.49 1.47 3.8 3.92 3.96 (AE*ab value) value Evaluation ∘∘∘ ∘∘∘ ∘∘∘ ∘∘∘ x x x *the content relative to the amount of thermally expandable microcapsules

INDUSTRIAL APPLICABILITY

[0210] The present invention can provide a thermally expandable microcapsule that has excellent heat resistance and compression resistance and that enables the production of a foam molded article that is less likely to undergo deterioration or appearance defects over a long period of time, as well as a foamable masterbatch and a foam molded article each produced using the thermally expandable microcapsule.