JPH0739155B2 - Magnetic composite type damping material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a magnetic composite type damping material of the type that is magnetically attracted to a vibration source.

[0002]

2. Description of the Related Art The inventors of the present invention have disclosed, as the above-mentioned magnetic composite type damping material, a three-layer structure in which a viscoelastic layer is provided between a magnetic material layer and a constraining material layer in Japanese Patent Laid-Open No. 3-47750. None, this 3
It has been disclosed that the damping material having a layered structure is directly attracted to the vibration source by the magnetic force of the magnetic material layer.

Since the magnetic composite type damping material having the above structure can be attracted to the vibration source by magnetic force, the workability of attaching to the vibration source is good. Further, the viscoelastic layer having a low elastic modulus is sandwiched between the magnetic material layer having a high elastic modulus and the constraining material layer, and the viscoelastic layer is sheared and deformed by the vibration generated from the vibration source ( Shear deformation) occurs, and mainly the viscoelastic layer converts the vibration energy into heat energy by shear deformation (shear deformation) and absorbs the vibration.

Further, in the case where the damping material having the structure in which the magnetic material layer is provided in the restraining material layer is directly attracted to the vibration source by the magnetic force of the magnetic material layer, it can be attracted to the vibration source by the magnetic force. Good installation workability. Also, in this case, by adsorbing to the vibration source only with magnetic force, the vibration generated from the vibration source causes a minute deviation at the interface with the vibration source, and the vibration energy is converted to thermal energy by the interface friction. Demonstrate the damping performance.

A structure in which a polymeric viscoelastic material having a small elastic modulus (for example, rubber) is sandwiched between two constraining plates having a large elastic modulus such as a metal plate, and the polymeric viscoelastic material sandwiched by vibration is used. In a constrained type damping material that causes shear deformation and converts vibration energy into heat energy, in order to efficiently transmit the vibration generated from the vibration source to the polymer viscoelastic material with a small elastic modulus, the damping material Must be firmly attached to the vibration source.

As a method of firmly adhering the vibration damping material to the vibration source, the adhesive force of the adhesive and mechanical fixing means such as bolting can be considered, but the magnetic composite type vibration damping material described above is temporarily adhered. In the case of bonding with an adhesive, even if the vibration absorbing action due to the interfacial friction described above cannot be expected, the damping material can be held by the vibration source with magnetic force until the adhesive is cured. Need not use
It is very useful for improving workability.

[0007]

However, like the above-mentioned magnetic composite type damping material, the magnetic source is closely attached to the vibration source by magnetic force,
A damping material that converts vibration energy into thermal energy by means of interfacial friction on the contact surface to suppress vibration has a characteristic that its damping characteristics have little temperature dependence and constant performance over a wide temperature range. However, the absolute value of the loss coefficient, which is an index of damping characteristics, is smaller than the peak value of the above-mentioned general restraint type damping material.

A general restraint type damping material has a loss coefficient peak near the glass transition point of a polymer viscoelastic material.
If it is used in a relatively narrow temperature range near its peak, the magnetic composite type damping material has a smaller loss coefficient than a general constrained type damping material, which is disadvantageous. However, the constrained type damping material that utilizes the shear deformation of the polymer viscoelastic material to convert vibration energy into thermal energy for vibration damping provides damping performance (excluding near the glass transition point of the polymer viscoelastic material). When the loss coefficient) is drastically decreased, the magnetic composite type damping material is advantageous in that a constant performance can be obtained in a wide temperature range although the absolute value of the loss coefficient is not large.

[0009]

SUMMARY OF THE INVENTION It is a principal object of the present invention to provide a new magnetic composite type damping material by providing the magnetic composite type damping material with the characteristics of a constrained type damping material.

[0010]

In order to achieve the above-mentioned object, the present invention provides a magnetic composite type vibration damping material constituted by adhering a magnetic polymer viscoelastic sheet to a constraining plate with an adhesive, wherein the magnetic polymer The viscoelastic sheet is a composition comprising a rubber / elastomer, an adhesive resin, a plasticizer, a magnetic powder, etc., wherein the adhesive resin and the plasticizer in the sheet are each 30 to 90 per 100 parts by weight of the rubber / elastomer. Parts by weight,
5 to 100 parts by weight, the magnetic powder in the sheet is 50 to 95% by weight based on the total weight of the sheet, and the elastic modulus of the adhesive after curing is equal to or higher than the elastic modulus of the sheet. Is the gist.

[0011]

The magnetic composite type vibration damping material is a vibration damping material having magnetic force and surface adhesiveness by virtue of the fact that the magnetic polymer viscoelastic sheet is mixed with the adhesive resin in a high ratio. Therefore, in the temperature range near the softening point of the adhesive resin, the adhesive force on the surface of the magnetic polymer viscoelastic sheet (hereinafter abbreviated as a sheet) increases, and the adhesive force and the magnetic force are applied to the vibration source. become. In this case, the sheet has a structure in which it is sandwiched between the vibration source and the restraint plate, and the vibration of the vibration source is converted into thermal energy by the shear deformation of the sheet.

Then, at a temperature below the softening point of the adhesive resin, the sheet is cured and the adhesiveness of the surface is lowered. Further, at a temperature equal to or higher than the softening point, the adhesive resin is rapidly plasticized, and a part of the adhesive resin increases in solubility in rubber, so that the adhesive resin moves to the inside of the rubber and the adhesiveness decreases. In these cases, the vibration damping material is adhered to the vibration source mainly by magnetic attraction, and the vibration energy is converted into thermal energy by the interfacial friction between the vibration damping material and the vibration source. Therefore, the damping property shows a relatively constant value except in the temperature range near the softening point of the adhesive resin, and is excellent in a wide temperature range having a peak in the temperature range near the softening point of the adhesive resin. Performance is obtained.

On the other hand, in the adhesive for adhering the sheet to the constraining plate, if the elastic modulus after curing is smaller than the elastic modulus of the sheet, the structure in which the sheet is constrained by the constraining plate does not occur, and the sheet is The elastic modulus of the adhesive after curing is required to be equal to or higher than the elastic modulus of the sheet because it freely follows the vibration and the vibration damping performance deteriorates. When the elastic modulus of the adhesive is smaller than the elastic modulus of the sheet, the adhesive layer has a structure sandwiched between the constraining plate having a large elastic modulus and the sheet, and the vibration damping property depends on the viscoelastic property of the adhesive. Become.

[0014]

1 is a cross-sectional view of a magnetic composite type damping material showing an embodiment of the present invention, in which 1 is a restraint plate, 2 is an adhesive layer, 3 is a viscoelastic magnetic polymer sheet, Reference numeral 4 is a vibration source.

As the constraining plate 1 having a large elastic modulus, iron,
Aluminum, stainless steel, copper and other metal plates, phenolic resin, polyamide, polycarbonate, polyester and other plastic plates, or fiber reinforced plastic plates obtained by reinforcing these plastics with glass fibers, carbon fibers, etc., slate plates, silica It is possible to use an inorganic rigid board such as a calcium acid board, a gypsum board, a fiber-containing cement board, or a ceramics board. The thickness of the constraining plate 1 is 1 to 40 mm, preferably 5 to 20 mm. In addition, a calcium silicate board and a gypsum board are used as a restraint board.
If you are using cement, fiber mixed cement board, etc.,
Restraint by covering the entire surface of the restraint plate with paint
The water absorption of the plate can be significantly reduced, and the absorbed water
It is possible to prevent the restraint plate from cracking due to freezing and thawing. That
In addition, by painting, the material is sunlight (ultraviolet rays),
Protect from environmental factors such as rain, sulfur dioxide, ozone
It is possible to improve durability. Painted restraint plate
The coating materials used are oil paints, nitrocellulose paints,
Alkyd resin paint, amino alkyd resin paint, vinyl resin
Oil paint, acrylic resin paint, epoxy resin paint, ureta
Resin paint, polyester resin paint, chlorinated rubber paint,
Inorganic paints are used.

The adhesive used for the adhesive layer 2 must have rigidity whose elastic modulus is equal to or higher than that of the magnetic polymer material sheet. As described above, when the elastic modulus of the adhesive is smaller than the elastic modulus of the magnetic polymer material sheet, the magnetic polymer material sheet does not have a structure constrained by the constraining plate, and the magnetic polymer material sheet is resistant to vibration. I followed freely,
Vibration control performance is reduced. As the adhesive to be used, it is possible to use epoxy resin-based, urea resin-based, melamine resin-based, phenol resin-based, vinyl acetate-based, cyanoacrylate-based, urethane-based, synthetic rubber-based, acrylic resin-based adhesives, etc. it can.

The polymer material used for the magnetic polymer viscoelastic sheet 3 is natural rubber, nitrile rubber, styrene butadiene rubber, butyl rubber, halogenated rubber, ethylene propylene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, acrylic rubber. Silicon rubber, fluororubber, epichlorohydrin rubber, urethane rubber, polynorbornene rubber, ethylene acrylic rubber, etc. are used.

As the adhesive resin added to the magnetic polymer viscoelastic sheet, coumarone-based resin such as coumarone-indene resin, coumarone-resin / naphthene-based oil / phenolic resin / rosin mixed product, P-3 -Butylphenol
Acetylene resin, phenol-formaldehyde resin,
Phenol / terpene resins such as terpene / phenolic resins, polyterpene resins, xylene formaldehyde resins, synthetic polyterpene resins, aromatic hydrocarbon resins,
Aliphatic hydrocarbon resin, unsaturated hydrocarbon polymer, hydrogenated hydrocarbon resin, petroleum hydrocarbon resin such as polybutene, glycerol ester of rosin, hydrogenated rosin, methyl ester high-melting ester of hydrogenated rosin Resins and rosin derivatives such as polymerized rosin can be used.

The plasticizer added to the magnetic polymer viscoelastic sheet includes petroleum-based process oils such as paraffin-based process oils, naphthene-based process oils, aromatic-based process oils, linseed oil, rapeseed oil, and the like. Vegetable oil, phthalic acid derivatives such as di (2-ethylhexyl) phthalate, diundecyl phthalate, dioctyl phthalate, adipic acid derivatives such as diisobutyl adipate, di (2-ethylhexyl) adipate, azelaine such as di (2-ethylhexyl) azelate An acid derivative, an epoxy derivative, etc. can be used.

The magnetic powder added to the magnetic polymer viscoelastic sheet includes ferrites such as barium ferrite and strontium ferrite, samarium cobalt-based ferrite,
Rare earth magnet powder such as neodymium iron boron type powder can be used. As the compounding agent to be added to the magnetic polymer viscoelastic sheet, there are a vulcanizing agent and a vulcanization accelerator, which are selected according to the type of rubber and an appropriate amount is compounded. In addition, a filler, a processing aid, an antiaging agent, etc. may be added.

The magnetic polymer viscoelastic sheet has a thickness of 0.1 to
10 mm, preferably about 3 to 7 mm. When the thickness of the constraining plate or the viscoelastic sheet of magnetic polymer is thin, when the vibration source is thick and the vibration energy is large, the vibration energy cannot be completely absorbed and a realistic effect cannot be expected. If it is too thick, it may fall off due to an increase in weight. The rubber used for the magnetic polymer viscoelastic sheet is vulcanized after being processed into a sheet or simultaneously. If you don't crosslink the rubber,
When the temperature rises, the entire magnetic polymer viscoelastic sheet is plasticized, so that the rigidity cannot be maintained in the high temperature range, and sliding friction at the interface with the vibration source cannot be expected.

The adhesive resin and the plasticizer added to the magnetic polymer viscoelastic sheet are added in an amount of 30 to 90 parts by weight, preferably 4 parts by weight, based on 100 parts by weight of the rubber.
About 0 to 70 parts by weight and about 5 to 100 parts by weight, preferably about 10 to 40 parts by weight of the plasticizer are preferable. When the amount of the adhesive resin and the plasticizer added is large, the rigidity of the magnetic polymer viscoelastic sheet at high temperature cannot be maintained, and the sheet processability deteriorates. Further, when the addition amount is small, the migration to the surface of the magnetic polymer viscoelastic sheet is small and the surface tackiness cannot be secured.

The amount of the magnetic powder added to the magnetic polymer viscoelastic sheet is preferably 50 to 95% by weight, and more preferably 70 to 85% by weight, based on the total composition. Since the magnetic force of the magnetic polymer viscoelastic sheet depends on the amount of the magnetic powder added, if the amount added is small, the magnetic force will be weak and dropout or the like will occur. On the other hand, if the amount of addition is too large, the workability of the viscoelastic sheet of magnetic polymer decreases and the sheet becomes brittle.

The magnetic polymer viscoelastic sheet is magnetized after molding. The magnetization is one-sided multi-pole magnetization in which the S pole and the N pole are alternately arranged on one side of the magnetic polymer viscoelastic sheet,
The pitch between the S and N poles is 1 to 20 mm, preferably 4 to 1
0mm is good. When the magnetizing pitch is shorter or wider than this, the attraction force of the magnetic polymer viscoelastic sheet decreases.

Example 1 A magnetic polymer viscoelastic sheet was prepared by kneading the compounding materials shown in Table 1 and performing molding vulcanization using a mold to give a thickness of 3
The sheet was molded into a sheet of mm and was magnetized on one side by a magnetizer at a magnetizing pitch of 8 mm. At this time, the residual magnetic flux density of the magnetic polymer viscoelastic sheet was 450 gauss. A 14 mm thick calcium silicate plate is used as the constraining plate having a high elastic modulus, a one-component urethane adhesive is used as the adhesive, and a magnetic polymer viscoelastic sheet is adhered to the constraining plate. 0.5kgf / c until the adhesive is hardened
A pressure-damping material was obtained by performing pressure-holding at about m ² .

[0026]

[Table 1]

The elastic modulus (E) of the magnetic polymer viscoelastic sheet and the adhesive is 2.3 × 10 ⁸ dyne / cm ² (25
C.) 1.8 × 10 ¹⁰ dyne / cm ² (25 ° C.).

Example 2 A magnetic polymer viscoelastic sheet was prepared by kneading the compounding materials shown in Table 2 and performing molding vulcanization using a mold to give a thickness of 3
The sheet was molded into a sheet of mm and was magnetized on one side by a magnetizer at a magnetizing pitch of 8 mm. At this time, the residual magnetic flux density of the magnetic polymer viscoelastic sheet was 440 gauss. A 14 mm thick calcium silicate plate is used as the constraining plate having a high elastic modulus, a one-component urethane adhesive is used as the adhesive, and a magnetic polymer viscoelastic sheet is adhered to the constraining plate. 0.5kgf / c until the adhesive is hardened
A pressure-damping material was obtained by performing pressure-holding at about m ² .

[0029]

[Table 2]

The elastic modulus (E) of the magnetic polymer viscoelastic sheet and the adhesive is 8.9 × 10 ⁸ dyne / cm ² (25
C.) 1.8 × 10 ¹⁰ dyne / cm ² (25 ° C.).

Example 3 and Example 4 As the magnetic polymer viscoelastic sheet, the sheet shown in Example 1 was used, and as the adhesive and the restraint plate, the materials shown in Table 3 were used. It was created.

[0032]

[Table 3]

When the magnetic polymer viscoelastic sheet was attached to the constraining plate with each adhesive, pressure-bonding was held at about 0.5 kgf / cm ² until the adhesive was hardened. The residual magnetic flux density of the damping material created in Example 3 is 450 gauss,
Elastic modulus (E) of magnetic polymer viscoelastic sheet and adhesive
Are 2.3 × 10 ⁸ dyne / cm ² (25 ° C.) and 1.
It was 8 × 10 ¹⁰ dyne / cm ² (25 ° C.). In addition, the residual magnetic flux density of the damping material created in Example 4 is 450 gauss,
Elastic modulus (E) of magnetic polymer viscoelastic sheet and adhesive
Are 2.3 × 10 ⁸ dyne / cm ² (25 ° C.) and 8.
It was 0 × 10 ⁹ dyne / cm ² (25 ° C.). Next, for comparison, the following damping material was created.

Comparative Example 1 As shown in Table 4, the magnetic polymer viscoelastic sheet was prepared by using a compounding material containing no adhesive resin and no plasticizer, and performing molding vulcanization using a mold to obtain a thickness. The sheet was molded into a 3 mm sheet, and single-sided multi-pole magnetization was performed with a magnetizer at a magnetizing pitch of 8 mm to prepare a magnetic polymer viscoelastic sheet with low adhesive strength. At this time, the residual magnetic flux density of the magnetic polymer viscoelastic sheet was 490 gauss. Next, the magnetic polymer viscoelastic sheet was attached to a calcium silicate plate having a thickness of 14 mm used as a restraint plate using a one-pack type urethane adhesive, and 0.5 kgf / cm until the adhesive hardened. ^A pressure-damping material was obtained by pressure-holding at about ² .

[0035]

[Table 4]

The elastic modulus (E) of the magnetic polymer viscoelastic sheet and the adhesive is 1.7 × 10 ⁹ dyne / cm ² (25
C.) 1.8 × 10 ¹⁰ dyne / cm ² (25 ° C.).

Comparative Example 2 The magnetic polymer viscoelastic sheet used in Example 1 is used.
Besides, the damping effect was confirmed by adhering the magnetic polymer viscoelastic sheet to the vibration source only by the adsorbing force of the sheet without using a restraint plate, an adhesive or the like.

Comparative Example 3 The vibration damping effect was confirmed in a state where the vibration damping material prepared in Example 1 was bonded to a vibration source using a one-component urethane adhesive. When the damping material was attached to the vibration source, it was pressure-bonded and held at about 0.5 kgf / cm ² until the adhesive was cured. Next, a vibration damping performance test was conducted on the vibration damping materials prepared in the above-mentioned respective examples and comparative examples.

Vibration damping performance test A rectangular base plate (this plate serves as a vibration source) was made from an iron plate having a thickness of 3 mm, and the vibration damping materials having the same dimensions prepared in the above-mentioned Examples or Comparative Examples were respectively applied thereto. Glued together
The center part of the base plate is excited by an electrodynamic exciter, and the force and vibration acceleration are measured by the impedance head inserted between them, while changing the excitation frequency and calculating the mechanical impedance at the excitation point. , A device (mechanical impedance method) for calculating a loss coefficient (a value indicating how fast vibration is attenuated) from a resonance curve is used. 2 and 3 show the loss coefficient measurement results for each of the examples and comparative examples.

The following can be seen from the loss coefficient measurement results of the damping materials of the above-mentioned examples and comparative examples. (1) When the magnetic polymer viscoelastic sheet alone was attached to the vibration source (Comparative Example 2), the loss coefficient value was higher than that of the magnetic composite type vibration damping material of the present invention (Example 1) to which a constraining plate was adhered. It can be seen that it is extremely small and the damping performance is low. (2) The damping material (Comparative Example 1) in which the adhesive strength is reduced without adding the adhesive resin plasticizer to the magnetic polymer viscoelastic sheet is
Since the vibration control is mainly due to the sliding friction at the interface between the vibration control material and the vibration source, the vibration control characteristic becomes a constant value at a relatively low level. (3) When the magnetic composite type vibration damping material is bonded to the vibration source with an adhesive (Comparative Example 3), a slight deviation does not occur at the interface between the vibration source and the vibration damping material, and the magnetic polymer viscoelastic sheet Has a structure constrained by a restraint plate and a vibration source, and its damping characteristics have a large temperature dependence, and have a peak at a temperature near the transition region of the magnetic polymer viscoelastic sheet. Therefore, the damping performance is good in the temperature range near the transition region of the magnetic polymer viscoelastic sheet, but sharply decreases in other temperature ranges. (4) In the vibration damping materials (Examples 1 to 4) of the present invention, the adhesive resin migrates to the surface of the magnetic polymer viscoelastic sheet, and in the temperature region near the softening point of the adhesive resin, the adhesion of the rubber surface is caused. As a result, the magnetic polymer viscoelastic sheet is constrained by the constraining plate and the vibration source. Further, in the case of a temperature other than the softening point of the adhesive resin, the adhesiveness is rapidly reduced by curing at a low temperature,
At high temperatures, plasticization reduces the tackiness, and therefore microscopic slippage at the interface between the vibration source and the damping material is likely to occur. For this reason, the vibration damping characteristics are excellent in that they have a peak in a certain temperature range but ensure a certain performance over a wide temperature range. Moreover, the peak temperature of the vibration damping performance can be adjusted by the types of the adhesive resin, the plasticizer, and the rubber. When the vibration energy of the vibration source is large, a practical effect can be expected by increasing the thickness of the damping material.

[0041]

As described above, according to the present invention,
The magnetic polymer viscoelastic sheet that constitutes the magnetic composite type vibration damping material not only retains the attractive force by the magnetic force but also has the surface adhesiveness, so that the synergistic effect of both the magnetic force and the adhesive force It is possible to obtain a magnetic composite type vibration damping material that exhibits good vibration damping performance in a wide temperature range.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a magnetic composite type damping material showing an embodiment of the present invention.

FIG. 2 is a graph showing vibration damping performance of Examples and Comparative Examples.

FIG. 3 is a graph showing vibration damping performance of Examples and Comparative Examples.

[Explanation of symbols]

 1 Restraint plate 2 Adhesive layer 3 Magnetic polymer viscoelastic sheet 4 Vibration source

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location B32B 25/04 27/18 H 8413-4F C08L 33/04 LHV LJA F16F 15/02 Q 9138-3J (72) Inventor Kazuo Nishimoto 135-1 Kamigashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa (72) Inventor Takahiro Niwa 3-6-10 Hirado, Totsuka-ku, Yokohama-shi, Kanagawa 306 (72) Inventor Shuji Ito Niiza, Saitama 2-22-2 Tohoku, Ichika No. 104, Akatsuka (56) Reference JP-A-63-97998 (JP, A) JP-A-3-47750 (JP, A)

Claims (3)

[Claims] 1. A magnetic composite type vibration damping material constituted by bonding a magnetic polymer viscoelastic sheet to a constraining plate with an adhesive,
The magnetic polymer viscoelastic sheet is a composition comprising a rubber / elastomer, an adhesive resin, a plasticizer, magnetic powder, etc.,
The adhesive resin and the plasticizer in the sheet are 30 to 90 parts by weight and 5 to 100 parts by weight, respectively, relative to 100 parts by weight of the rubber / elastomer, and the magnetic powder in the sheet is 50 to 95 parts by weight based on the total weight of the sheet. %, And the elastic modulus of the adhesive after curing is equal to or higher than the elastic modulus of the sheet. 2. A calcium silicate plate or slate having a thickness of the magnetic polymer viscoelastic sheet of 0.1 to 10 mm, a rubber / elastomer of acrylic rubber, and a thickness of the constraining plate of 1 to 40 mm. The magnetic composite damping material according to claim 1, which is a plate. 3. The magnetic composite type vibration damping material according to claim 1, wherein the entire surface of the constraining plate is covered with a coating material.