JPH07146684A - Damping powder - Google Patents

Abstract

PURPOSE:To apply a damping powder to various use by incorporating a resin composed of methyl methacrylate as a main structural unit and an inorganic filler composed of a hydroxide. CONSTITUTION:The damping powder contains 20-50wt.% resin composed of methyl methacrylate as the main structural unit and 50-80wt.% inorganic filler composed of the hydroxide. Particularly the damping member is preferably 0.01-0.1 in loss factor (n) measured by mechanical impedance method. In this case, other components except methyl methacrylate are used for copolymerizing as the resin and as the copolymerizing components, alphabeta-ethylenic unsaturated compound except methyl methacrylate such as vinyl acetate, styrene, methyl acrylate, cyclohexane methacrylate are exemplified and these one or more kinds can be copolymerized. And the damping powder 10 is filled into the inside of a speaker placing plate 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electronic equipment, measuring equipment,
The present invention relates to a powder applicable to various applications such as precision processing equipment, audio equipment, a mounting base for audio equipment, an audio room, and the like, in which the influence of vibration is required to be eliminated.

[0002]

2. Description of the Related Art In various fields such as precision electronic equipments, precision measuring equipments, precision processing machines, audio equipments, video equipments, musical instruments, and buildings, measures have been taken to eliminate the influence of vibration. As a damping material used for that purpose, for example, a material in which a resin such as polypropylene is highly filled with a damping filler, or a sandwich type damping plate in which a resin is sandwiched between steel sheets has been developed.

[0003]

However, conventional damping materials cannot always exhibit sufficient damping performance, and since they are rigid, they have shape restrictions and are applicable to applicable applications. There was a limit.

The present invention has been made in order to solve the above problems, and provides a vibration damping powder which eliminates the influence of vibration from the surroundings and which can be applied to various purposes. Is.

[0005]

The damping powder of the present invention comprises a resin containing methyl methacrylate as a main constituent unit in an amount of 20-5.
0 to 80% by weight of inorganic filler consisting of hydroxide
% By weight.

In particular, the loss coefficient (η) measured by the mechanical impedance method is preferably 0.01 to 0.1.

[0007]

In the damping powder of the present invention, the resin containing methyl methacrylate as a main constituent unit is a synthetic resin containing 80% by weight or more, preferably 90% by weight or more of methyl methacrylate (MMA) units. When the synthetic resin has 80% by weight or more of methyl methacrylate unit, the processability, impact resistance, weather resistance and flame retardancy of the vibration damping powder can be improved. In particular, when it is used as a vibration damping powder for various audio-visual equipments, musical instruments, etc., it is possible to obtain a more excellent sound quality as compared with that using unsaturated polyester as a resin. In the present invention, it is also possible to copolymerize a component other than methyl methacrylate as a resin, as the copolymerization component, vinyl acetate, styrene, methyl acrylate, ethyl acrylate, butyl acrylate, ethyl methacrylate, Examples include α, β-ethylenically unsaturated compounds other than methyl methacrylate such as butyl methacrylate, cyclohexyl acrylate, and cyclohexane methacrylate, and one or more of these can be copolymerized. Furthermore, compounds having a plurality of polymerizable double bonds in the molecule such as ethylene glycol dimethacrylate can also be used.

Examples of the inorganic filler include hydroxides such as aluminum hydroxide, calcium hydroxide and magnesium hydroxide. These hydroxides release water of crystallization at a high temperature, so that the flame retardancy of the vibration damping powder can be improved. Among them, aluminum hydroxide is particularly suitable. 50-80% by weight of these inorganic fillers in the damping powder.
The content is particularly preferably 60 to 70% by weight. By containing 50% by weight or more of the inorganic filler,
It is possible to improve not only vibration damping performance but also appearance such as color and luster, weight feeling, touch feeling, and flame retardancy. Further, when the content is 80% by weight or less, workability, impact resistance and the like can be improved. The particle size of the inorganic filler is 1
~ 150μm is preferable, the center diameter of the particle size distribution is 1
Those having a thickness of 0 to 100 μm are particularly preferable. As the inorganic filler, those whose surface is treated with a silane coupling agent, a titanate coupling agent, stearic acid or the like can be used.

The damping powder of the present invention includes, in addition to those mentioned above, crushed resin such as ABS resin, epoxy resin, melamine resin and phenol resin, colorants such as pigments and dyes,
Additives such as an ultraviolet absorber, a flame retardant, a release agent, a fluidizing agent, a thickener, etc. may be further compounded to such an extent that the characteristics of the present invention are not deteriorated.

The damping material of the present invention has a loss coefficient (η) measured by the mechanical impedance method of 0.01 to
It is preferably 0.1. This is the loss factor (η)
If the value is less than 0.01, the vibration damping property becomes too low and resonance is likely to occur. On the contrary, if the value exceeds 0.1, the vibration absorption becomes too large and the sound quality tends to deteriorate. It is preferably in the range of 0.01 to 0.05.

The mechanical impedance method is often used for measuring the loss coefficient, and as shown in FIG. 2, the loss coefficient (η) can be calculated as a frequency response curve of vibration (acceleration: A) / excitation force. It is obtained from the half-value width, and a measurement system as shown in FIG. 3 is used for actual measurement. The measurement of the loss factor by this mechanical impedance method
Suitable for materials with high vibration damping performance.

The damping powder preferably has a specific gravity of 1.5 to 2.5, especially 1.6 to 2.0, from the viewpoint of damping performance.

Regarding the particle size of the vibration damping powder, only pulverized products or fine powders having a large particle size may be used, or both may be mixed or used with an appropriate particle size distribution. From the viewpoint, a mesh of 150 mesh or less is particularly preferable.

In order to produce the damping powder of the present invention, for example, a monomer containing methyl methacrylate as a main component or a partial polymer thereof is uniformly mixed with an inorganic filler and a polymerization initiator and defoamed. A method of later injecting into the mold and polymerizing,
Molded product molded by a method such as homogeneously mixing resin powder and inorganic filler and then press-molding in a molding die is crushed using a crusher such as a low crusher, and if necessary, classified to a desired particle size. To obtain a damping powder of. As the polymerization initiator, benzoyl peroxide, lauroyl peroxide, 2,2′azobisisobutyronitrile or the like can be used. A monomer containing methyl methacrylate as a main component or a partial polymer thereof or a mixture of resin powder and an inorganic filler is added to a resin containing methyl methacrylate as a main constituent unit in an amount of 20 to 50% by weight and a hydroxide. 50% to 80% by weight of an inorganic filler to form a resin composition having a particle size of 0.2 to 5 m.
You may add what was grind | pulverized to about m in the range of 20-90 weight%.

[0015]

【Example】

Example 1 A syrup 35 comprising 20% by weight of polymethylmethacrylate and 80% by weight of methylmethacrylate.
%, And 65% by weight of aluminum hydroxide powder having a center particle size of 30 μm, benzoyl peroxide was added as a polymerization initiator, and the mixture was poured into a mold and cured at room temperature to obtain a molded product. It was crushed to a particle size of 150 mesh or less using a roll crusher to obtain a damping powder having a specific gravity of 1.8. The loss coefficient (η) of the obtained molded body was measured by the mechanical impedance method. The loss coefficient (η) of the molded product was 0.03, and the molded product had extremely excellent vibration damping performance. Then, as shown in FIG. 1, the obtained damping powder 10 was filled in the speaker mounting table 12. The sound quality was investigated with the speaker 14 on the speaker mounting table 12 having the damping powder 10 filled therein and the same speaker on the conventional speaker mounting table. As a result, using the speaker mounting table 12 filled with the damping powder of the present invention, clear and excellent sound quality without noise or sound distortion could be obtained.

Example 2 Polymethylmethacrylate was added to 2
Benzoyl peroxide was added as a polymerization initiator to a mixture of 35% by weight of syrup consisting of 0% by weight and 80% by weight of methyl methacrylate, and 65% by weight of aluminum hydroxide powder having a central particle diameter of 30 μm, It was poured into a mold and cured at room temperature. A disk-shaped molded body having a specific gravity of 1.8, a thickness of 13 mm and a diameter of 100 mm was obtained from the obtained molded body. The compact was crushed to a particle size of 150 mesh or less using a roll crusher to obtain a damping powder having a specific gravity of 1.8. The loss coefficient (η) of the obtained molded body was measured by the mechanical impedance method. The loss coefficient (η) of the molded product was 0.03, and the molded product had extremely excellent vibration damping performance. 50% by weight of the obtained damping powder was mixed with 50% by weight of an epoxy resin and used as an encapsulating resin for a transformer. As a result, in the conventional transformer, so-called squeaking occurred, but in the transformer using the encapsulating resin of the present example, no squeaking occurred, which was effective in preventing the squeaking of the transformer, which was a conventional problem. Met.

Example 3 The damping powder obtained in the same manner as in Example 1 was embedded in the wall material surrounding the listening dome. As a result, it was possible to improve the sound quality of the music generated in the listening room, compared to before the damping powder of this example was embedded in the wall material.

Example 4 The damping powder obtained in the same manner as in Example 1 was spread on the floor of a listening room. As a result, it was possible to improve the sound quality of the music generated in the listening room, compared to before spreading the damping powder.

[Example 5] Damping powder obtained in the same manner as in Example 1 was mixed with a coating material and applied to the wall surface of a listening room. As a result, it was possible to improve the sound quality of the music generated in the listening room, as compared with before the application of the paint.

As described above, since the damping powder of the present invention is not a molded body, it has no shape restriction and can be widely used in various applications. For example, if the damping powder of the present invention is used as a damping powder-containing paint as described above, not only wall materials but also audio equipment, air conditioning equipment, computers, etc.
Vibrations can be reduced by applying various materials as needed.

[0021]

The damping powder of the present invention comprises 20 to 50% by weight of a resin having methyl methacrylate as a main constituent unit and 50 to 80% by weight of an inorganic filler composed of a hydroxide. Therefore, it can be easily used for machines, instruments, devices and structures that have high vibration damping performance and are required to suppress vibration.

In particular, since the damping powder of the present invention is in the form of powder, it is not subject to shape restrictions and has a very wide range of uses. In addition, it is an epoch-making thing that the vibration damping performance can be exhibited by a method such as applying the paint.

[Brief description of drawings]

FIG. 1 is a partially transparent perspective view showing a speaker mounting table of the present embodiment.

FIG. 2 is a graph showing a method for measuring mechanical impedance.

FIG. 3 is a schematic diagram showing a mechanical impedance measurement system.

[Explanation of symbols] 10 Damping powder 12 Speaker mounting base

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G10K 11/162

Claims (2)

[Claims] 1. A vibration damping method, comprising 20 to 50% by weight of a resin containing methyl methacrylate as a main constituent unit and 50 to 80% by weight of an inorganic filler composed of a hydroxide. Powder. 2. The damping powder according to claim 1, wherein the loss coefficient (η) according to the mechanical impedance method is 0.01 to 0.1.