Activated carbon for speaker apparatus, activated carbon sheets for speaker apparatus, and speaker apparatus

Abstract

To provide activated carbon for a speaker apparatus which is excellent in suppression effect of pressure fluctuations.SOLUTION: There is provided an activated carbon for speaker apparatuses, wherein the activated carbon has, out of pore volumes calculated by the QSDFT method from a nitrogen adsorption isotherm, a pore volume A of 0.15 cc / g or more for a pore diameter in the range of 1.0 nm or less. Since the activated carbon of the present invention has, out of pore volumes calculated by the QSDFT method from the nitrogen adsorption isotherm, a pore volume of 0.15 cc / g or more for a pore diameter in the range of 1.0 nm or less, it is excellent in suppression effect of pressure fluctuations, and is particularly suitable for use in speaker apparatuses.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to activated carbon for a speaker device, an activated carbon sheet for a speaker device, and a speaker device. [Background technology]

[0002] In general, in small speaker devices, the volume of the speaker cabinet is small, so that it is difficult to reproduce low frequencies due to the influence of acoustic stiffness. That is, when an electric signal is applied to a speaker, the speaker vibrates, compressing the air inside the cabinet, which acts as an air spring and impedes the movement of the speaker, lowering the sound pressure level especially in the low frequency range, and making it impossible to achieve sufficient low frequency reproduction. In order to realize low frequency reproduction with a small speaker device, a speaker device has been proposed in which a gas-adsorbing material such as activated carbon is placed inside the cabinet.

[0003] For example, an adsorption material for a speaker device is known, which is activated carbon with a cumulative pore volume of 18 to 50 Å radius of 0.4 ml / g or more (see, for example, Patent Document 1). This activated carbon is unlikely to adsorb moisture even in an atmosphere with relatively high humidity, and therefore, when this activated carbon is placed inside the cabinet of a speaker device, it is said that even in an atmosphere with high humidity, it can reduce the pressure fluctuation of the gas inside the cabinet caused by the vibration of the speaker, thereby obtaining a sufficient bass reproduction effect and obtaining an acoustic effect equivalent to that obtained when a large-capacity cabinet is used.

[0004] For example, an adsorption material for a speaker device is known, which is activated carbon with a cumulative pore volume of 0.5 ml / g or more and a radius of 18 Å or less (see, for example, Patent Document 2). When placed inside the cabinet of a speaker device, this activated carbon is said to mitigate the pressure fluctuation of the gas inside the cabinet caused by the vibration of the speaker, provide a sufficient bass reproduction effect, and provide an acoustic effect equivalent to that obtained when a large-capacity cabinet is used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-27527 A [Patent Document 2] JP 2009-27526 A Summary of the Invention [Problem to be solved by the invention]

[0006] As a result of the inventors' studies, they found that the activated carbons for speaker devices of Patent Documents 1 and 2 still have room for improvement in the effect of suppressing pressure fluctuations.

[0007] Therefore, a main object of the present invention is to provide activated carbon for a speaker device which solves the above problems and has an excellent effect of suppressing pressure fluctuations. [Means for solving the problem]

[0008] Patent Document 1 discloses that if the cumulative pore volume of pores with a radius of 18 Å or less (i.e., pore diameter of 3.6 nm or less) exceeds 0.2 ml / g, the amount of moisture adsorption tends to be relatively high in a humidity range of about 50 to 70%, and sufficient bass reproduction effect may not be obtained in the speaker device. Patent Document 2 discloses that if the cumulative pore volume of activated carbon with a radius of 7 Å or less (i.e., pore diameter of 1.4 nm or less) is 0.1 ml / g or more, the speaker device obtained may not be able to fully recover the decrease in sound pressure level in the bass range. That is, Patent Documents 1 and 2 teach that in order to improve the bass reproduction effect, the pore volume of pores with a diameter in the range of 1.4 nm or less should be made as small as possible.

[0009] However, the inventors of the present invention have conducted extensive research and found that activated carbon with a pore volume of 0.15 cc / g or more for pores with diameters of 1.0 nm or less, calculated from the nitrogen desorption isotherm by the QSDFT method, has an excellent effect of suppressing pressure fluctuations and is therefore particularly suitable for use in speaker devices. The present invention was completed based on these findings and through further research.

[0010] That is, the present invention provides the following aspects. Item 1. Activated carbon for speaker devices, in which the pore volume A of pores with diameters of 1.0 nm or less is 0.15 cc / g or more, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm. Item 2. The activated carbon for a speaker device according to item 1, wherein the pore volume of pores having diameters of 1.5 nm or less is 0.25 cc / g or more, as calculated from a nitrogen desorption isotherm by a QSDFT method. Item 3. The activated carbon for a speaker device according to Item 1, wherein the pore volume of pores having diameters of 3.5 nm or more exceeds 0.2 cc / g, as calculated from a nitrogen desorption isotherm by a QSDFT method. Item 4. The activated carbon for a speaker device according to item 1, wherein the pore volume calculated from the nitrogen desorption isotherm by the QSDFT method has a pore volume of pores having diameters of 3.5 nm or more of less than 0.4 cc / g. Item 5. The activated carbon for a speaker device according to Item 1, wherein the activated carbon is fibrous activated carbon. Item 6. An activated carbon sheet for a speaker device, comprising the activated carbon for a speaker device according to item 5, the activated carbon sheet for a speaker device being a wet-laid nonwoven fabric. Item 7. A speaker device comprising the activated carbon for a speaker device according to any one of items 1 to 5. Effect of the Invention

[0011] According to the activated carbon for speaker devices of the present invention, the pore volume of pores with diameters of 1.0 nm or less, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, is 0.15 cc / g or more, and therefore the activated carbon has an excellent effect of suppressing pressure fluctuations, making it particularly suitable for use in speaker devices. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a speaker device using the activated carbon for a speaker device of the present invention. [Diagram 2] 4 is a graph showing a pore size distribution of the activated carbon for the speaker device of Example 1, calculated by a QSDFT method. [Diagram 3] 11 is a graph showing a pore size distribution of the activated carbon for a speaker device of Example 2, calculated by a QSDFT method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The activated carbon for a speaker device of the present invention has a pore volume of 0.15 cc / g or more having a pore diameter of 1.0 nm or less, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm. The activated carbon for a speaker device of the present invention will be described in detail below.

[0014] [Pore diameter and pore volume] In the present invention, the pore diameter and pore volume of the activated carbon are values ​​calculated by the QSDFT method (Quenched Solid Density Functional Theory) from the nitrogen desorption isotherm (relative pressure 0.02 to 0.995) measured at a temperature of 77K. The QSDFT method is an analytical method that targets pore diameter analysis of geometrically and chemically irregular microporous and mesoporous carbons and can calculate the pore diameter distribution from about 0.5 nm to about 40 nm. The QSDFT method is a method that significantly improves the accuracy of pore diameter distribution analysis because it clearly takes into account the effects of roughness and non-uniformity of the pore surface. In the present invention, the nitrogen desorption isotherm can be measured using a gas adsorption amount measuring device such as "AUTOSORB-1-MP" manufactured by Quantachrome, and the pore diameter distribution analysis by the QSDFT method can be performed by applying N2 at 77K on carbon [slit pore, QSDFT equilibrium model] as a calculation model.

[0015] In the activated carbon for a speaker device of the present invention, the pore volume A of pores with diameters of 1.0 nm or less is 0.15 cc / g or more among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm. By making the pore volume A 0.15 cc / g or more, the pressure fluctuation suppression effect is excellent. From the viewpoint of making the pressure fluctuation suppression effect more excellent, the pore volume A is preferably 0.15 to 0.4 cc / g. In addition, the pore volume A can be set to 0.17 to 0.23 cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume A can be set to 0.27 to 0.33 cc / g from the viewpoint of improving the suppression effect of pressure fluctuation.

[0016] In the activated carbon for a speaker device of the present invention, the pore volume of the pores having a pore diameter of 0.65 nm or less among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.02 to 0.15 cc / g, preferably 0.03 to 0.12 cc / g. In addition, the pore volume can be 0.03 to 0.065cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0nm to 5.0nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0nm to 5.0nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume can be 0.08 to 0.11cc / g from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0017] In the activated carbon for a speaker device of the present invention, the pore volume of the pores having a pore diameter of 1.5 nm or less among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.25 cc / g or more, preferably 0.25 to 0.7 cc / g, and more preferably 0.25 to 0.60 cc / g. In addition, the pore volume can be 0.25 to 0.35 cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume can be 0.5 to 0.6 cc / g from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0018] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter in the range of 2.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.3 to 0.9 cc / g, preferably 0.35 to 0.85 cc / g. In addition, the pore volume can be 0.35 to 0.45 cc / g from the viewpoint of making the pore volume of the pore diameter in the range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, which will be described later, larger by, for example, 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter in the range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter in the range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.75 to 0.85 cc / g.

[0019] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter in the range of 2.5 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.4 to 1.0 cc / g, preferably 0.45 to 0.9 cc / g. In addition, the pore volume can be 0.45 to 0.55 cc / g from the viewpoint of making the pore volume of the pore diameter in the range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, which will be described later, larger by, for example, 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter in the range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter in the range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.8 to 0.9 cc / g.

[0020] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter in the range of 3.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.5 to 1.0 cc / g, preferably 0.55 to 0.95 cc / g. In addition, the pore volume can be 0.55 to 0.65 cc / g from the viewpoint of making the pore volume of the pore diameter in the range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, which will be described later, larger by, for example, 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter in the range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter in the range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.8 to 0.95 cc / g.

[0021] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter in the range of 3.5 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.65 to 1.0 cc / g, preferably 0.7 to 0.95 cc / g. In addition, the pore volume can be 0.73 to 0.78 cc / g from the viewpoint of making the pore volume of the pore diameter in the range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, which will be described later, larger by, for example, 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter in the range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter in the range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.85 to 0.95 cc / g.

[0022] In the activated carbon for a speaker device of the present invention, the pore volume of the pores having a pore diameter of 4.0 nm or less among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.8 to 1.0 cc / g, preferably 0.85 to 0.95 cc / g.

[0023] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter in the range of 4.5 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.8 to 1.1 cc / g, preferably 0.85 to 1.0 cc / g. In addition, the pore volume can be 0.91 to 0.95 cc / g from the viewpoint of making the pore volume of the pore diameter in the range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later larger by, for example, 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter in the range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter in the range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.85 to 0.90 cc / g.

[0024] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter in the range of 5.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.8 to 1.1 cc / g, preferably 0.85 to 1.0 cc / g. In addition, the pore volume can be 0.91 to 0.95 cc / g from the viewpoint of making the pore volume of the pore diameter in the range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later larger by, for example, 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter in the range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter in the range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.85 to 0.90 cc / g.

[0025] In the activated carbon for speaker device of the present invention, the total pore volume T calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.8 to 1.2 cc / g, preferably 0.85 to 1.1 cc / g. The total pore volume T can be 1.0 to 1.1 cc / g, from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the total pore volume T can be set to 0.85 to 0.90 cc / g.

[0026] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 0.65 nm or more and 1.0 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.1 to 0.25 cc / g, preferably 0.12 to 0.23 cc / g. In addition, the pore volume can be 0.12 to 0.15 cc / g from the viewpoint of making the effect of suppressing pressure fluctuations even better, while increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced. In addition, the pore volume can be 0.19 to 0.23 cc / g from the viewpoint of making the effect of suppressing pressure fluctuations even better.

[0027] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 1.0 nm or more and 1.5 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.08 to 0.3 cc / g, preferably 0.09 to 0.28 cc / g. In addition, the pore volume can be 0.09 to 0.13cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume can be 0.23 to 0.28cc / g from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0028] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 1.5 nm or more and 2.0 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.04 to 0.25 cc / g, preferably 0.05 to 0.24 cc / g. In addition, the pore volume can be 0.05 to 0.11 cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume can be 0.18 to 0.24 cc / g from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0029] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 2.0 nm or more and 2.5 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.04 to 0.12 cc / g, preferably 0.05 to 0.1 cc / g.

[0030] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 2.5 nm or more and 3.0 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.01 to 0.15 cc / g, preferably 0.01 to 0.13 cc / g. In addition, the pore volume can be 0.1 to 0.13 cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume can be 0.01 to 0.03 cc / g from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0031] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 3.0 nm or more and 3.5 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.001 to 0.25 cc / g, preferably 0.001 to 0.2 cc / g. In addition, the pore volume can be 0.15 to 0.2 cc / g from the viewpoint of making the effect of suppressing pressure fluctuations even better, while increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced. In addition, the pore volume can be 0.005 cc / g or less from the viewpoint of making the effect of suppressing pressure fluctuations even better.

[0032] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter range of 3.5 nm to 4.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.15 cc / g or less, preferably 0.12 cc / g or less. In addition, the pore volume can be 0.08 to 0.13 cc / g from the viewpoint of making the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later larger by, for example, 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is easily reduced while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.001 cc / g or less, more preferably 0.000 cc / g.

[0033] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter range of 4.0 nm to 4.5 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.1 cc / g or less, preferably 0.08 cc / g or less. In addition, the pore volume can be 0.03 to 0.08 cc / g from the viewpoint of making the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later larger, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.001 cc / g or less, more preferably 0.000 cc / g.

[0034] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter range of 4.5 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.08 cc / g or less, preferably 0.05 cc / g or less. In addition, the pore volume can be 0.01 to 0.05 cc / g from the viewpoint of making the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later larger, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.001 cc / g or less, more preferably 0.000 cc / g.

[0035] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter in the range of 5.0 nm or more in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, 0.12 cc / g or less, preferably 0.1 cc / g or less. In addition, the pore volume can be 0.05 to 0.1 cc / g from the viewpoint of making the pore volume of the pore diameter in the range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later larger, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter in the range of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture in the pores with a pore diameter in the range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.001 cc / g or less, more preferably 0.000 cc / g.

[0036] In the activated carbon for speaker device of the present invention, the pore volume of the pore diameter range of 3.5 nm or more in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be, for example, less than 0.4 cc / g, preferably 0.35 cc / g or less, more preferably 0.3 cc / g or less. In addition, the pore volume may be more than 0.2 cc / g, preferably more than 0.2 cc / g and less than 0.4 cc / g, more preferably 0.25 to 0.3 cc / g, from the viewpoint of improving the suppression effect of pressure fluctuation while adsorbing moisture in the speaker cabinet to pores with a pore diameter range of 2.0 nm to 5.0 nm, and easily reducing pore blockage due to moisture in pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm. Moreover, from the viewpoint of achieving an even more excellent effect of suppressing pressure fluctuations, the pore volume can be set to 0.001 cc / g or less, more preferably 0.000 cc / g.

[0037] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 2.0 nm or more and 3.5 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.05 to 0.45 cc / g, preferably 0.08 to 0.4 cc / g. In addition, the pore volume can be 0.3 to 0.4 cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume can be 0.08 to 0.15 cc / g from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0038] In the activated carbon for a speaker device of the present invention, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume of the pores having a pore diameter in the range of 2.0 nm or more and 5.0 nm or less is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be, for example, 0.05 to 0.7 cc / g, preferably 0.08 to 0.6 cc / g. In addition, the pore volume can be 0.5 to 0.6 cc / g from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the pore volume can be 0.08 to 0.15 cc / g from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0039] In the activated carbon for speaker device of the present invention, the ratio of the pore volume A of pores with a diameter of 1.0 nm or less to the total pore volume T of the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm (pore volume A / total pore volume T×100(%)) is not particularly limited as long as the pore volume A satisfies the above-mentioned range, but may be 10 to 40%. In addition, the ratio may be 13 to 22% from the viewpoint of increasing the pore volume of the pores with a diameter of 2.0 nm to 5.0 nm of the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a diameter of 2.0 nm to 5.0 nm, and reducing the pore blockage due to moisture of the pores with a diameter of 1.0 nm or less of the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm while improving the suppression effect of pressure fluctuation. Moreover, from the viewpoint of achieving an even better effect of suppressing pressure fluctuations, the ratio can be set to 30 to 40%.

[0040] In the activated carbon for a speaker device of the present invention, the ratio of the pore volume of pores with diameters in the range of 2.0 nm or less to the total pore volume T, calculated by the QSDFT method from the nitrogen desorption isotherm (pore volume of pores with diameters in the range of 2.0 nm or less / total pore volume T×100(%)), is not particularly limited as long as the pore volume A satisfies the above-mentioned range, and may be 30 to 90%. In addition, the ratio can be 30 to 45% from the viewpoint of increasing the pore volume of the pore diameter range of 2.0 nm to 5.0 nm in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, so that the moisture in the speaker cabinet is adsorbed into the pores with a pore diameter range of 2.0 nm to 5.0 nm, and the pore blockage due to moisture in the pores with a pore diameter range of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm can be easily reduced while improving the suppression effect of pressure fluctuation. In addition, the ratio can be 85 to 95% from the viewpoint of further improving the suppression effect of pressure fluctuation.

[0041] [Other properties of the activated carbon for speaker device of the present invention] The specific surface area of ​​the activated carbon for a speaker device of the present invention is not particularly limited as long as the pore volume A satisfies the above-mentioned range. 2 / g or more 2300m 2 The specific surface area is preferably 1000 m / g or less, from the viewpoint of increasing the pore volume of the pores having a pore diameter of 2.0 nm or more and 5.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, for example, by 0.5 cc / g or more, thereby allowing the moisture in the speaker cabinet to be adsorbed into the pores having a pore diameter of 2.0 nm or more and 5.0 nm or less, and facilitating the reduction in the pore blockage due to moisture in the pores having a pore diameter of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, while improving the effect of suppressing pressure fluctuations. 2 / g or more 1400m 2 From the viewpoint of achieving a more excellent effect of suppressing pressure fluctuations, the specific surface area can be set to 1600 m 2 / g or more 2000m 2 In the present invention, the specific surface area of ​​the activated carbon is a value determined by the BET method (one-point method in which the measurement point is a relative pressure of 0.1) using nitrogen as an adsorbed substance.

[0042] The form of the activated carbon for a speaker device of the present invention is not particularly limited, and may be, for example, fibrous, granular, powdery, etc. In terms of improving processability and suppressing generation of coal dust from a sheet containing the activated carbon for a speaker device of the present invention, the activated carbon is preferably fibrous.

[0043] When the activated carbon for speaker device of the present invention is made fibrous, the tensile strength of the fibrous activated carbon is not particularly limited, but may be 0.1 to 0.25 GPa. In addition, the tensile strength is such that, while the effect of suppressing pressure fluctuation is improved, the pore volume of the pore diameter range of 2.0 nm to 5.0 nm is increased, for example, by 0.5 cc / g or more, among the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm described later, and the moisture in the speaker cabinet is adsorbed into the pores of the pore diameter range of 2.0 nm to 5.0 nm, among the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, and the pore blockage due to moisture of the pores of the pore diameter range of 1.0 nm or less is easily reduced, the pores are highly developed, and the tensile strength of the fibrous activated carbon tends to decrease, and the tensile strength in this case may be 0.1 to 0.15 GPa.

[0044] [Method of manufacturing the activated carbon for speaker device according to the present invention] The method for producing the activated carbon for a speaker device of the present invention is not particularly limited, and may include, for example, a production method including a step of activating an activated carbon precursor made of coal pitch in an atmosphere with a HO concentration of 100% by volume at an atmospheric temperature of 870 to 880°C for 45 to 55 minutes.

[0045] In order to increase the pore volume of the pores having a pore diameter of 2.0 nm or more and 5.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, for example, by 0.5 cc / g or more, and adsorb moisture in the speaker cabinet into pores having a pore diameter of 2.0 nm or more and 5.0 nm or less, thereby easily reducing pore blockage due to moisture in the pores having a pore diameter of 1.0 nm or less in the pore volume calculated by the QSDFT method from the nitrogen desorption isotherm, a production method including a step of incorporating yttrium into the activated carbon precursor and activating the precursor at an atmosphere having an HO concentration of 100% by volume at an atmospheric temperature of 890 to 910°C for 20 to 30 minutes can be mentioned.

[0046] The content of yttrium in the activated carbon precursor when yttrium is contained may be 0.05 to 0.5 mass %. Yttrium can be contained by mixing yttrium alone or an yttrium compound with the raw material. Examples of yttrium compounds include inorganic metal compounds such as metal oxides, metal hydroxides, metal halides, and metal sulfates, which contain yttrium as a constituent metal element, salts of organic acids such as acetic acid and metals, and organometallic compounds. Examples of organometallic compounds include metal acetylacetonates and aromatic metal compounds. The content of yttrium is determined by the ratio of yttrium elemental conversion measured by incinerating the activated carbon precursor, dissolving the ash in acid, and measuring the yttrium content by an ICP emission spectrometer (Varian, Model 715-ES).

[0047] The activated carbon precursor is then activated in an atmosphere with an H2O concentration of 100% by volume at the above-mentioned temperature and time to obtain the activated carbon for the speaker device of the present invention. In addition, when the activated carbon precursor is activated by containing yttrium, the yttrium can be completely removed by washing the obtained activated carbon.

[0048] [Activated carbon sheet for speaker equipment] The activated carbon sheet for a speaker device of the present invention contains the activated carbon for a speaker device of the present invention.

[0049] The form of the activated carbon sheet for speaker device of the present invention may be, for example, a wet nonwoven fabric such as a wet paper-making nonwoven fabric, or a dry nonwoven fabric such as a needle punch nonwoven fabric. In particular, when the activated carbon for speaker device of the present invention has a pore volume of pore diameters in the range of 2.0 nm to 5.0 nm, which is calculated from the nitrogen desorption isotherm by the QSDFT method, and is large, for example, 0.5 cc / g or more, the tensile strength of the fibrous activated carbon decreases. In this case, when the activated carbon for speaker device of the present invention is made into a dry nonwoven fabric, the fibrous activated carbon is more likely to be cut, and the generation of coal dust from the sheet tends to increase. Therefore, in the above case, from the viewpoint of increasing the dimensional stability and further suppressing the generation of coal dust from the sheet, it is preferable to make the sheet into a wet nonwoven fabric, more preferably a wet paper-making nonwoven fabric.

[0050] [Speaker equipment] The speaker device of the present invention will be described with reference to Fig. 1. In Fig. 1, the speaker device 1 has a cabinet 2, a speaker unit 4 attached to the cabinet, and activated carbon for a speaker device 6 arranged in a space 3 inside the cabinet. This speaker device is a bass reflex type speaker device having a bass reflex port 5 in the cabinet 2. The type of the speaker device of the present invention is not particularly limited, and may be a sealed type speaker device.

[0051] 1, the activated carbon 6 for the speaker device may be in various shapes such as granular, powdered, fibrous, sheet, etc. In the case of granular or powdered activated carbon, it is preferable to place it in the chamber 3 after wrapping it in a breathable wrapping material such as woven fabric or nonwoven fabric. EXAMPLES

[0052] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the examples.

[0053] <Example 1> A mixture of 100 parts by mass of granular coal pitch with a softening point of 280°C and 1.3 parts by mass of yttrium acetylacetonate was fed to a melt extruder, melt mixed at a melting temperature of 320°C, and spun at a discharge rate of 20g / min to obtain pitch fiber. The obtained pitch fiber was subjected to infusibilization treatment by increasing the temperature from room temperature to 354°C in air at a rate of 1 to 30°C / min for 54 minutes, to obtain an activated carbon precursor, which is an infusibilized pitch fiber. In the activated carbon precursor, the content of yttrium and yttrium compounds (yttrium element equivalent) was 0.25 parts by mass.

[0054] The obtained activated carbon precursor was activated by continuously introducing a gas with an H2O concentration of 100% by volume into an activation furnace and heat-treating it at an atmospheric temperature of 900°C for 25 minutes, thereby obtaining a fibrous activated carbon for a speaker device of Example 1.

[0055] <Example 2> Granular coal pitch with a softening point of 280°C was fed to a melt extruder, melt mixed at a melting temperature of 320°C, and spun at a discharge rate of 20g / min to obtain pitch fiber. The obtained pitch fiber was heated in air from room temperature to 354°C at a rate of 1 to 30°C / min for 54 minutes to perform infusibilization treatment, and an activated carbon precursor, which is an infusibilized pitch fiber, was obtained. The obtained activated carbon precursor was continuously introduced into an activation furnace with a gas having a H2O concentration of 100% by volume, and heat-treated at an atmospheric temperature of 875°C for 50 minutes to obtain a fibrous activated carbon for a speaker device of Example 2.

[0056] <Evaluation method> (1) Yttrium content (mass%) of activated carbon precursor (infusible pitch fiber) The pitch fibers were pulverized, and the proportion of yttrium converted into elemental yttrium measured using an energy dispersive X-ray fluorescence analyzer (NEX DE, manufactured by Rigaku Corporation) was determined as the yttrium content.

[0057] (2) Pore volume (cc / g) and specific surface area (m 2 / g) The pore properties were measured from the nitrogen adsorption isotherm at 77K (relative pressure 0.02 to 0.995) using Quantachrome's "AUTOSORB-1-MP". The specific surface area was calculated from the measurement point at a relative pressure of 0.1 by the BET method. The total pore volume and the pore volume in each pore diameter range listed in Table 1 were analyzed by calculating the pore diameter distribution by applying N2at 77K on carbon [slit pore, QSDFT equilibrium model] as a calculation model to the measured nitrogen desorption isotherm. Specifically, the pore volume in each pore diameter range listed in Table 1 is the read value of the graph showing the pore diameter distribution shown in Figures 2 and 3 or a value calculated from the read value. More specifically, the pore volume of the pore diameter in the range of 0.65 nm or less is the read value of the cumulative pore volume (cc / g) at the horizontal axis Pore Width of the pore diameter distribution diagram of 0.65 nm. Similarly, the pore volume A of the pore diameter in the range of 1.0 nm or less, the pore volume of the pore diameter in the range of 1.5 nm or less, the pore volume of the pore diameter in the range of 2.0 nm or less, the pore volume of the pore diameter in the range of 2.5 nm or less, the pore volume of the pore diameter in the range of 3.0 nm or less, the pore volume of the pore diameter in the range of 3.5 nm or less, the pore volume of the pore diameter in the range of 4.0 nm or less, the pore volume of the pore diameter in the range of 4.5 nm or less, and the pore volume of the pore diameter in the range of 5.0 nm or less were obtained. The pore volume of the pore diameter in the range of 0.65 nm to 1.0 nm was calculated by subtracting the pore volume of the pore diameter in the range of 0.65 nm or less from the pore volume A of the pore diameter in the range of 1.0 nm or less. The pore volume of the pore diameter range of 1.0 nm to 1.5 nm was calculated by subtracting the pore volume A of the pore diameter range of 1.0 nm or less from the pore volume of the pore diameter range of 1.5 nm or less. The pore volume of the pore diameter range of 1.5 nm to 2.0 nm was calculated by subtracting the pore volume of the pore diameter range of 1.5 nm or less from the pore volume of the pore diameter range of 2.0 nm or less. The pore volume of the pore diameter range of 2.0 nm to 2.5 nm was calculated by subtracting the pore volume of the pore diameter range of 2.0 nm or less from the pore volume of the pore diameter range of 2.5 nm or less.The pore volume of the pore diameter in the range of 2.5 nm to 3.0 nm was calculated by subtracting the pore volume of the pore diameter in the range of 2.5 nm or less from the pore volume of the pore diameter in the range of 3.0 nm or less. The pore volume of the pore diameter in the range of 3.0 nm to 3.5 nm was calculated by subtracting the pore volume of the pore diameter in the range of 3.0 nm or less from the pore volume of the pore diameter in the range of 3.5 nm or less. The pore volume of the pore diameter in the range of 3.5 nm to 4.0 nm was calculated by subtracting the pore volume of the pore diameter in the range of 3.5 nm or less from the pore volume of the pore diameter in the range of 4.0 nm or less. The pore volume of the pore diameter in the range of 4.0 nm to 4.5 nm was calculated by subtracting the pore volume of the pore diameter in the range of 4.0 nm or less from the pore volume of the pore diameter in the range of 4.5 nm or less. The pore volume of the pore diameter in the range of 4.5 nm to 5.0 nm was calculated by subtracting the pore volume of the pore diameter in the range of 4.5 nm or less from the pore volume of the pore diameter in the range of 5.0 nm or less. The pore volume of the pore diameter in the range of 5.0 nm or more was calculated by subtracting the pore volume of the pore diameter in the range of 5.0 nm or less from the total pore volume T obtained by the QSDFT method. The pore volume of the pore diameter in the range of 3.5 nm or more was calculated by subtracting the pore volume of the pore diameter in the range of 3.5 nm or less from the total pore volume T obtained by the QSDFT method. The pore volume of the pore diameter in the range of 2.0 nm to 3.5 nm was calculated by subtracting the pore volume of the pore diameter in the range of 2.0 nm or less from the pore volume of the pore diameter in the range of 3.5 nm or less. The pore volume of pores with diameters in the range of 2.0 nm to 5.0 nm was calculated by subtracting the pore volume of pores with diameters in the range of 2.0 nm or less from the pore volume of pores with diameters in the range of 5.0 nm or less. The results are shown in Table 1. In addition, a graph showing the pore size distribution of the activated carbon for a speaker device of Example 1 calculated by the QSDFT method is shown in FIG. 2, and a graph showing the pore size distribution of the activated carbon for a speaker device of Example 2 calculated by the QSDFT method is shown in FIG. 3.

[0058] (3) Tensile strength of fibrous activated carbon (GPa) The tensile strength was measured in accordance with "7.3.2 Tensile strength" of JIS K 1477:2007 "Test methods for fibrous activated carbon" using a tensile tester (product name: SIMADZU EZ-SX) manufactured by Shimadzu Corporation as the measuring instrument. Specifically, a test piece was prepared by fixing both ends of a single piece of fibrous activated carbon to a test mount. The test piece was attached to the tensile tester, and the test mount for the test piece was cut to perform a tensile test on the fibrous activated carbon. The tensile test was performed with the test piece length set to 10.0±0.2 mm and the tensile speed set to 1 mm / min. The force (N) applied when cutting the fibrous activated carbon was calculated based on the average fiber diameter described above and expressed as the fiber cross-sectional area (mm 2 ) and convert the unit to GPa (1GPa=1000N / mm 2 The tensile strength was calculated by the following equation. The results are shown in Table 1.

[0059] (4) Pressure fluctuation suppression effect The fibrous activated carbon was dried in a dryer at 100℃ for 2 hours. A 100mL plastic syringe with a digital pressure gauge attached to the tip was prepared as a compression container. 5g of fibrous activated carbon was placed in it, and compressed from 100mL to 30mL at a speed of 8.3mm / s using an autograph made by Shimadzu Corporation, and the peak pressure and the pressure after 1 minute were measured. The results are shown in Table 2.

[0060] [Table 1]

[0061] [Table 2]

[0062] As is clear from Tables 1 and 2, the activated carbons for speaker devices in Examples 1 and 2 had a pore volume of 0.15 cc / g or more for pore diameters of 1.0 nm or less, calculated from the nitrogen desorption isotherm by the QSDFT method, and therefore had an excellent effect of suppressing pressure fluctuations, making them particularly suitable for use in speaker devices. [Explanation of symbols]

[0063] 1 Speaker device 2 Cabinet 3 Vacancies 4 Speaker unit 5 Bass reflex port 6 Activated carbon for speaker devices

Claims

1. Activated carbon for a speaker device, in which the pore volume A of pores having diameters of 1.0 nm or less is 0.15 cc / g or more, among the pore volumes calculated by the QSDFT method from a nitrogen desorption isotherm.

2. 2. The activated carbon for a speaker device according to claim 1, wherein the pore volume of pores having diameters of 1.5 nm or less is 0.25 cc / g or more, as calculated from a nitrogen desorption isotherm by a QSDFT method.

3. 2. The activated carbon for a speaker device according to claim 1, wherein the pore volume of pores having diameters of 3.5 nm or more in the pore volume calculated by the QSDFT method from a nitrogen desorption isotherm exceeds 0.2 cc / g.

4. 2. The activated carbon for a speaker device according to claim 1, wherein the pore volume of pores having diameters of 3.5 nm or more is less than 0.4 cc / g, as calculated from a nitrogen desorption isotherm by a QSDFT method.

5. 2. The activated carbon for a speaker device according to claim 1, wherein the activated carbon is a fibrous activated carbon.

6. An activated carbon sheet for a speaker device, comprising the activated carbon for a speaker device according to claim 5, The activated carbon sheet for a speaker device is made of a wet-laid nonwoven fabric.

7. A speaker device comprising the activated carbon for a speaker device according to any one of claims 1 to 5.

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