JP2007071347A - Vibration damping material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration damping material capable of being shaped corresponding to the shape of an object (a vibrator) which generates vibration, having improved vibration damping performance and sound proofing performance. <P>SOLUTION: The vibration damping material comprises a foamed adhesive layer integrally laminated on one face of a thermoplastic resin foamed sheet containing an inorganic compound. It contains a 30-300 pts.wt. inorganic compound in terms of a 100 pts.wt. thermoplastic resin of the thermoplastic resin foamed sheet, and so it has improved sound proofing performance, particularly, sound insulating performance, vibration damping performance, and shaping quality. It can be precisely shaped in a form corresponding to the shape of the vibrator by using a known shaping method, and stably adhered onto the vibrator with almost no gap between the vibrator and itself, resulting in reliable vibration damping treatment and sound proofing treatment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration damping material having excellent vibration damping properties, soundproofing properties, and moldability.

  Conventionally, vibration control materials have been used in electrical appliances to reduce vibrations of drive devices such as motors. In addition, in construction applications, vibration control materials have been used to reduce rain noise on folded plate roofs. In automobile applications, damping materials are used to reduce vibration noise caused by the vibration of the roof, doors, and the like due to vibrations generated during traveling and vibrations of the drive system such as the engine.

  As such a damping material, Patent Document 1 discloses a folded plate roof in which a polyethylene terephthalate resin layer is laminated on one surface of a damping sheet base material made of rubber or thermoplastic elastomer, thermoplastic resin and inorganic powder. A vibration damping sheet has been proposed.

  This vibration damping sheet contains inorganic powder and converts vibration energy into heat energy to absorb vibration energy. However, since it contains inorganic powder, it has low bendability and extensibility. Therefore, it is difficult to form along the shape of an object (hereinafter, sometimes referred to as “vibrating body”) that generates vibration, and the vibration damping sheet is placed on the surface of the vibrating body. There was a problem that it was difficult to attach without causing a gap between them.

  In addition, in automobile applications, in addition to the drive system vibration described above, the intrusion of sound generated from the engine into the vehicle interior is a factor that deteriorates the interior sound environment. For this reason, the engine, floor seat, trunk Soundproof material is used for

As such a soundproofing material, in Patent Document 2, a binder component containing 90% by weight or more of a rubber component, a filler component and additives are kneaded and rolled, and an elastic modulus at 20 ° C. is 5 × 10 ⁷ Pa. The following sound-insulating sheets have been proposed.

  In order to increase the density and to provide sound insulation, this sound insulation sheet contains a filler component in the binder component. Therefore, the sound insulation sheet has a high specific gravity and is hard. In addition to being difficult to cut, the moldability such as bending is poor.

  Further, the sound insulating sheet is poor in extensibility, and even if an attempt is made to mold the sound insulating sheet using a mold, the sound insulating sheet is cracked or cut, and formed into a molded product having a desired shape. I could not.

  Therefore, even if a sound insulating sheet is formed in a state along the shape of the vibrating metal plate on a vibrating metal plate having a complicated shape such as a floor steel plate of an automobile, the sound insulating sheet is attached to the vibrating metal plate. Since it cannot be accurately formed into a shape that conforms to the shape, there is a problem that a gap is formed between the sound insulating sheet and the vibration metal plate, and a work for filling the gap is required separately.

Japanese Patent Laid-Open No. 10-183883 JP-A-6-301385

  The present invention provides a vibration damping material that can be molded along the shape of an object (vibrating body) that generates vibrations and that has excellent vibration damping properties and excellent soundproofing properties.

  As shown in FIG. 1, the vibration damping material A of the present invention has a foamed adhesive layer C laminated and integrated on one surface of a thermoplastic resin foam sheet B containing an inorganic compound. 30 to 300 parts by weight of an inorganic compound is contained with respect to 100 parts by weight of the thermoplastic resin constituting B.

  The thermoplastic resin constituting the thermoplastic resin foam sheet B is not particularly limited, and examples thereof include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl acetate. Besides polyolefin resins such as polyethylene resins, propylene homopolymers, polypropylene resins such as copolymers of propylene and other olefins, polystyrene resins, polyester resins, polyamide resins, polyimide resins, Organic materials such as petroleum resins are listed, and the damping material is excellent in rigidity, and is less likely to bend and warp during handling, and is excellent in workability. Polyolefin resins are preferable, and polyethylene resins and More preferably, an ethylene-vinyl acetate copolymer is used in combination.

  And the soundproofing performance is provided to the damping material A by making the said thermoplastic resin foam sheet B contain an inorganic compound in a predetermined ratio. Examples of such inorganic compounds include metal hydroxides such as aluminum hydroxide and magnesium hydroxide in addition to metal salts of inorganic acids such as barium sulfate and magnesium sulfate. Since it is heated, a metal salt of an inorganic acid that is not likely to be decomposed by this heating is preferable, and barium sulfate is more preferable.

  Further, if the content of the inorganic compound in the thermoplastic resin foam sheet B is small, the soundproofing property of the vibration damping material is lowered, whereas if it is large, the moldability of the vibration damping material is lowered. It is limited to 30 to 300 parts by weight with respect to 100 parts by weight of the thermoplastic resin constituting B, and is preferably 75 to 250 parts by weight.

  Thus, in the damping material A of the present invention, excellent soundproofing performance is imparted by filling the thermoplastic resin foam sheet B with an inorganic compound at a predetermined ratio. Here, when a thermoplastic resin is highly filled with an inorganic filler, particularly an inorganic compound having a large specific gravity such as barium sulfate, generally, the thermoplastic resin has a reduced extensibility and a moldability is lowered. It becomes difficult to apply a forming method such as vacuum forming.

  Therefore, in the vibration damping material of the present invention, the thermoplastic resin is foamed into a thermoplastic resin foam sheet to complement the decrease in elongation of the thermoplastic resin due to the inclusion of the inorganic compound, and this thermoplastic resin foam sheet. An inorganic compound is contained therein. In this way, by expanding the thermoplastic resin into a thermoplastic resin foam sheet, it is possible to improve the elongation at break when the thermoplastic resin is pulled, and as a result, molding the thermoplastic resin foam sheet. The vibration damping material can be accurately formed into a desired shape using a known forming method such as vacuum forming.

  That is, since the damping material A of the present invention has a thermoplastic resin foamed to improve the stretchability as a thermoplastic resin foamed sheet, the thermoplastic resin foamed sheet can be highly filled with an inorganic compound. As a result, the vibration damping material of the present invention has excellent soundproofing properties and excellent moldability.

And when the apparent density of the thermoplastic resin foam sheet B containing an inorganic compound is small, the soundproofing property of the vibration damping material may be lowered, while when it is large, the moldability of the vibration damping material may be lowered. Therefore, 0.1 to 0.8 g / cm ³ is preferable, and 0.25 to 0.7 g / cm ³ is more preferable. In addition, the apparent density of the thermoplastic resin foam sheet B containing an inorganic compound refers to that measured according to JIS Z6767.

  In addition, the resin magnification of the thermoplastic resin constituting the thermoplastic resin foam sheet B decreases the extensibility of the thermoplastic resin constituting the thermoplastic resin foam sheet B, and the moldability of the damping material is reduced. Since it may decrease, 300% or more is preferable, 500% or more is more preferable, and if it is too large, the vibration damping material may be torn or cracked at the time of molding the vibration damping material. 1000% or less is more preferable.

The resin magnification of the thermoplastic resin constituting the thermoplastic resin foam sheet is an index indicating the volume expansion coefficient before and after foaming of the thermoplastic resin itself, and specifically, calculated by the following formula 1. Say. The density of the inorganic compound is Ag / cm ^3, and the density of the thermoplastic resin constituting the thermoplastic resin foam sheet is Bg / cm ³ . The weight of the inorganic compound contained in the thermoplastic resin foam sheet is Xg, and the weight of the thermoplastic resin is Yg. The apparent density of the entire thermoplastic resin foam sheet containing an inorganic compound is Cg / cm ³ .

  And if the thickness of the thermoplastic resin foam sheet B is thin, the soundproofing property of the damping material may be lowered or the mechanical strength of the damping material may be lowered. Since it may fall, 2-4 mm is preferable.

  Next, the manufacturing method of the thermoplastic resin foam sheet B containing an inorganic compound is demonstrated. The method for producing the thermoplastic resin foam sheet B is not particularly limited. For example, (1) a general-purpose stirrer such as a lab plast mill is used for a foamable resin composition comprising a thermoplastic resin, an inorganic compound, and a pyrolytic foaming agent. A foamable resin sheet is produced by a general-purpose molding method such as press molding after being supplied to the apparatus and melt-kneaded, and this foamable resin sheet is ionized such as electron beam, α-ray, and β-ray as necessary. A method of producing a thermoplastic resin foamed sheet by heating and foaming the foamable resin sheet to a temperature equal to or higher than the decomposition temperature of the thermally decomposable foaming agent after crosslinking by irradiating radiation; (2) a thermoplastic resin; A foamable resin composition comprising an inorganic compound and a thermally decomposable foaming agent is supplied to an extruder, melted and kneaded, and the foamable resin sheet is continuously extruded from the extruder. After cross-linking by irradiating ionizing radiation such as strands, α rays, β rays, etc., the foamable resin sheet is heated to a temperature equal to or higher than the decomposition temperature of the thermally decomposable foaming agent and foamed to form a thermoplastic resin foam sheet The method of manufacturing continuously is mentioned.

  The pyrolytic foaming agent is not particularly limited as long as it is conventionally used in the production of foamed sheets. For example, azodicarbonamide, benzenesulfonylhydrazide, dinitrosopentamethylenetetramine, toluenesulfonyl Examples thereof include hydrazide and 4,4-oxybis (benzenesulfonylhydrazide), and these may be used alone or in combination of two or more.

  Furthermore, a foamed adhesive layer C is laminated and integrated on one surface of the thermoplastic resin foam sheet B. It does not specifically limit as an adhesive which comprises this foaming adhesive layer C, For example, a urethane type adhesive, an acrylic adhesive, etc. are mentioned, It is preferable that the acrylic adhesive is contained.

  As a method for producing the foamed pressure-sensitive adhesive layer C using the above-mentioned pressure-sensitive adhesive, a widely used method can be used. For example, this foamed pressure-sensitive adhesive is prepared by mixing air into a pressure-sensitive adhesive emulsion and then foaming. The method of apply | coating an emulsion by arbitrary thickness to arbitrary surfaces and drying it is mentioned.

  Furthermore, by adding a crosslinking agent in the foamed adhesive layer C to crosslink the foamed adhesive layer C, the thickness accuracy of the foamed adhesive layer C is maintained while maintaining the damping action by the viscoelasticity of the foamed adhesive layer C. Can be improved. Such a crosslinking agent is not particularly limited as long as the foamed pressure-sensitive adhesive layer C can be crosslinked, and examples thereof include an epoxy crosslinking agent, an amine crosslinking agent, and a silane crosslinking agent.

  Moreover, as content of the crosslinking agent in the foaming adhesive layer C, when there is much, the crosslinking density of a foaming adhesive layer will become high too much, and the damping effect by the viscoelasticity of a foaming adhesive layer may decline on the contrary. Therefore, 6 parts by weight or less is preferable with respect to 100 parts by weight of the resin component constituting the foamed adhesive layer C, and 1 to 4 parts by weight is more preferable.

And, if the density of the foamed pressure-sensitive adhesive layer C is low, the vibration damping effect due to the viscoelasticity of the foamed pressure-sensitive adhesive layer may be reduced, whereas if it is high, the lightness of the vibration damping material may be reduced. preferably 0.05 to 1 g / cm ^3, more preferably ^{0.1~1g / cm 3, 0.15~1g / cm} 3 is particularly preferred.

  Furthermore, if the thickness of the foamed pressure-sensitive adhesive layer C is thin, the vibration damping performance of the vibration damping material may be reduced. On the other hand, if the thickness is large, the light weight of the vibration damping material may be reduced. 5 mm is preferable, and 1 to 3 mm is more preferable.

  Further, in order to improve the lightness of the damping material A, it is preferable that the foamed adhesive layer C does not contain an inorganic filler. Examples of such inorganic fillers include, for example, calcium carbonate, magnesium carbonate, silicates (kaolin, talc, etc.), silicic acid (diatomaceous earth, light anhydrous silicic acid, white carbon, etc.), zinc oxide (zinc white). , Titanium oxide, barium sulfate, calcium sulfate and the like.

  Next, the method for producing the damping material A by laminating and integrating the foamed adhesive layer C on one surface of the thermoplastic resin foam sheet B is not particularly limited. For example, on the one surface of the thermoplastic resin foam sheet B A method of manufacturing a vibration damping material by laminating and integrating a foamed adhesive layer C via a double-sided adhesive tape, and a vibration damping material by laminating and integrating the foamed adhesive layer C via a pressure sensitive adhesive on one surface of a thermoplastic resin foam sheet B Method of manufacturing material A, after directly applying the foamed adhesive emulsion on one surface of the thermoplastic resin foam sheet B, drying the foamed adhesive emulsion, and foaming adhesive layer C on one surface of the thermoplastic resin foam sheet B And the like, and the like.

  Further, if the thickness of the damping material A is thin, the damping performance of the damping material may be reduced or the mechanical strength may be reduced. On the other hand, if the thickness is thick, the lightness of the damping material may be reduced. Since there exists, 4-7 mm is preferable.

  In addition, although the case where the foaming adhesive layer C was laminated and integrated on one surface of the thermoplastic resin foam sheet B was explained as the damping material A, a plurality of damping materials A, A. And may be laminated and integrated. In this case, it is necessary to laminate a plurality of damping materials A, A... So that the thermoplastic resin foam sheet B and the foamed adhesive layer C are alternated with each other.

  The damping material A is used by being fixed to the surface of the vibrating body such that the foamed adhesive layer C is on the vibrating body side. The damping material A is a thermoplastic resin having excellent moldability. Since the foamed adhesive layer C is laminated and integrated on one surface of the foamed sheet B and has excellent moldability, it can be formed into a shape that conforms to the shape of the vibrator.

  Therefore, the damping material A can be fixed to the surface of the vibrating body so as not to generate a gap between the vibrating body, and the vibration energy of the vibrating body can be reliably converted into thermal energy by the damping material A. It is possible to attenuate the vibration of the vibrating body to reduce or stop the vibration of the vibrating body, and to reduce or stop the noise generated from the vibrating body by reducing or stopping the vibration of the vibrating body.

  And the damping material A is also provided with soundproofing performance by the thermoplastic resin foam sheet B, and also exhibits a shielding effect of noise generated from the vibrating body, and noise generated from the opposite side across the damping material A. Shields and exhibits excellent soundproofing.

  As a method of fixing the damping material A to the surface of the vibrating body, for example, a method of fixing the damping material A to the surface of the vibrating body using a double-sided adhesive tape or an adhesive, foaming of the damping material A Examples thereof include a method of fixing the damping material A to the surface of the vibrating body with the adhesive force of the adhesive layer C. In addition, as a molding method for molding the vibration damping material, a conventionally known molding method can be used, and examples thereof include vacuum molding and pressure molding.

  In the vibration damping material of the present invention, a foamed adhesive layer is laminated and integrated on one surface of a thermoplastic resin foam sheet containing an inorganic compound, and 100 parts by weight of the thermoplastic resin constituting the thermoplastic resin foam sheet In contrast, since the inorganic compound is contained in an amount of 30 to 300 parts by weight, it has excellent vibration damping properties and soundproofing properties, in particular, sound insulation properties and excellent moldability.

  Therefore, since the vibration damping material of the present invention can be accurately molded using a known molding method in a form that conforms to the shape of the vibration body, the vibration damping material is almost between the vibration body and the vibration body. It is possible to stably stick without generating a gap, and it is possible to reliably perform the vibration damping process and the soundproofing process.

  Furthermore, in the vibration damping material of the present invention, when the thermoplastic resin constituting the thermoplastic resin foam sheet is a polyolefin-based resin, it has excellent rigidity and is less likely to bend or warp during handling. Also excellent in properties.

  In the vibration damping material of the present invention, when the inorganic compound is a metal salt of an inorganic acid, the thermoplastic resin foam sheet can be stably formed despite the heat applied when the vibration damping material is molded. Exists, and the damping material can be formed into a desired shape without impairing its soundproofing performance.

Further, in the vibration damping material of the present invention, when the apparent density is 0.1 to 0.8 g / cm ³ , the vibration damping material has more excellent soundproofing and moldability.

Example 1
90 parts by weight of water-acrylic adhesive emulsion (trade name “Boncoat 350” manufactured by Dainippon Ink and Chemicals, Inc., acrylic adhesive component (resin component): 50% by weight), water-urethane adhesive emulsion (Dainippon Ink) Product name “Hydran HW-930” manufactured by Kagaku Co., Ltd., 10 parts by weight of urethane-based adhesive component (resin component): 50% by weight, ammonium chloride-based foaming agent (trade name “F-1” manufactured by Dainippon Ink and Chemicals, Inc.) 5 parts by weight, 2 parts by weight of an epoxy-based crosslinking agent (trade name “CR-5L” manufactured by Dainippon Ink Chemical Co., Ltd.), and a silicone foam stabilizer (trade name “Boncoat NBA-1” manufactured by Dainippon Ink Chemical Co., Ltd.) 5 parts by weight and 6 parts by weight of a carboxymethylcellulose aqueous solution (manufactured by Daicel Chemical Industries, Ltd., 4% by weight) were uniformly mixed and then filtered to prepare a pressure-sensitive adhesive emulsion. Using whisk foamed by mixing air down to prepare a foaming adhesive emulsion.

Next, after preparing a polyethylene terephthalate film with one surface being a release-treated surface, and applying the foamed adhesive emulsion to the release-treated surface of the polyethylene terephthalate film so as to have a uniform thickness, the foamed adhesive emulsion The foamed adhesive sheet was prepared by laminating a 2.8 mm thick foamed adhesive layer (density: 0.20 g / cm ³ ) on a polyethylene terephthalate film.

  Meanwhile, 65 parts by weight of low density polyethylene (trade name “LE520” manufactured by Sumitomo Mitsui Polyolefin Co., Ltd.), ethylene-vinyl acetate copolymer (trade name “Evaflex EV460” manufactured by Mitsui DuPont Polychemical Co., Ltd.), vinyl acetate content: 19 weight %) 35 parts by weight, barium sulfate (trade name “W-1” manufactured by Takehara Chemical Co., Ltd.) 150 parts by weight, azodicarbonamide (trade name “Uniform AZ SO-40” manufactured by Otsuka Chemical Co., Ltd.), and foaming aid As a foaming resin composition consisting of 1 part by weight of zinc stearate (trade name “SZ-2000” manufactured by Sakai Chemical Co., Ltd.), supplied to a lab plast mill, kneaded at 110 ° C. for 15 minutes and uniformly mixed Then, the foamable resin composition was press-molded at 110 ° C. to produce a foamable resin sheet having a thickness of 2.5 mm.

The foamable resin sheet was cross-linked by irradiating the foamable resin sheet with 2.0 Mrad of an electron beam under the condition of 800 KV. This foamable resin sheet is supplied to an oven, and the foamable resin sheet is left to foam at 240 ° C. for 80 seconds to be foamed from a polyolefin resin composed of low-density polyethylene and an ethylene-vinyl acetate copolymer. A foamed thermoplastic resin sheet containing barium sulfate was obtained. The obtained thermoplastic resin foam sheet containing barium sulfate had an apparent density of 0.33 g / cm ³ and a thickness of 3.7 mm. The density of the polyolefin resin comprising low density polyethylene and ethylene-vinyl acetate copolymer was 0.9 g / cm ³ , and the density of barium sulfate was 4.3 g / cm ³ . The resin magnification of the polyolefin resin constituting the thermoplastic resin foam sheet was 650.4%.

  Then, the foamed adhesive sheet is laminated on one surface of the thermoplastic resin foam sheet with a double-sided adhesive tape (trade name “No5761” manufactured by Sekisui Chemical Co., Ltd.) in a state where the foamed adhesive layer faces the thermoplastic resin foam sheet. Thus, a vibration damping material obtained by laminating and integrating a foamed adhesive layer on one surface of a thermoplastic resin foam sheet was obtained.

(Example 2)
Instead of laminating a foamed pressure-sensitive adhesive layer having a thickness of 3.2 mm and a density of 0.20 g / cm ³ on the polyethylene terephthalate film, a foamed pressure-sensitive adhesive sheet is produced instead of a thickness of 2.9 mm on the polyethylene terephthalate film. A foamed pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that a foamed pressure-sensitive adhesive sheet was produced by laminating a 0.23 g / cm ³ foamed pressure-sensitive adhesive layer.

In addition, 100 parts by weight of barium sulfate instead of 150 parts by weight, 3 parts by weight of azodicarbonamide instead of 4 parts by weight, 0.8 parts by weight of zinc stearate instead of 1 part by weight A thermoplastic resin foam sheet was obtained in the same manner as in Example 1 except that. In addition, the obtained thermoplastic resin foam sheet had an apparent density of 0.32 g / cm ³ and a thickness of 3.6 mm. Further, the resin magnification of the polyolefin resin constituting the thermoplastic resin foam sheet was 541.6%.

  And the foaming adhesive layer was laminated | stacked and integrated on the one surface of the thermoplastic resin foam sheet in the same way as Example 1, and the damping material was obtained.

(Comparative Example 1)
A foamed pressure-sensitive adhesive sheet was produced in the same manner as in Example 2. On the other hand, ethylene-propylene random copolymer (trade name “XK0235” manufactured by Chisso Corporation) 45 parts by weight, isotactic homopolypropylene (trade name “SH152” manufactured by Idemitsu Co., Ltd.) 15 parts by weight, linear low density polyethylene (Idemitsu) Product name “0238CN”) 40 parts by weight, azodicarbonamide 6.8 parts by weight, cross-linking agent (trade name “TND-23H” manufactured by Kyoei Chemical Co., Ltd.) 3 parts by weight, antioxidant A (product of Asahi Denka Co., Ltd.) Name “Adekastab AO-60”) 1 part by weight, antioxidant B (trade name “Adekastab CDA-1” manufactured by Asahi Denka Co., Ltd.) 0.5 part by weight and antioxidant C (trade name “made by Ouchi Shinsei Chemical Co., Ltd.” Nocrack 400S ") 0.5 parts by weight was supplied to an extruder, melt kneaded and extruded to obtain a foamable resin sheet having a thickness of 1.2 mm.

The foamable resin sheet was cross-linked by irradiating an electron beam with 3.6 krad at 800 kV on both sides of the obtained foamable resin sheet. Next, this foamable resin sheet was heated to 250 ° C. to obtain a thermoplastic resin foam sheet having a thickness of 3.0 mm and a density of 0.07 g / cm ³ . The density of the ethylene-propylene random copolymer, isotactic homopolypropylene and linear low density polyethylene was 0.9 g / cm ³ , and the density of barium sulfate was 4.3 g / cm ³ . The resin magnification of the polyolefin resin constituting the thermoplastic resin foam sheet was 1285.7%.

  And the foaming adhesive layer was laminated | stacked and integrated on the one surface of the thermoplastic resin foam sheet in the same way as Example 1, and the damping material was obtained.

(Comparative Example 2)
An ethylene-propylene-diene rubber (EPDM) sheet (apparent density: 2.4 g / cm ³ , thickness: 2.0 mm) was used as a damping material.

(Comparative Example 3)
Damping material formed by laminating and integrating an aluminum sheet on one side of a butyl rubber sheet containing an inorganic filler (Nitto Denko's trade name “Legertrex DN300”, apparent density: 2.2 g / cm ³ , thickness: 1.5 mm ) Was used.

  The damping properties, moldability and soundproofing properties of the obtained damping material were measured in the following manner, and the results are shown in Tables 1 and 2 and FIG.

(Vibration control)
The loss factor at 270 to 5000 Hz was measured in accordance with the central support steady excitation method defined in JIS G0602. Specifically, a 15 mm long x 250 mm flat rectangular test piece is cut out from the vibration damping material, and this test piece is a SPCC steel plate (planar rectangular shape (15 mm long, 250 mm wide), thickness) specified in JIS G3141. 0.8 mm), and a loss factor at 270 to 4600 Hz was measured through a double-sided adhesive tape (trade name “Sekisui Tape No. 5761” manufactured by Sekisui Chemical Co., Ltd.). Results are shown. In addition, when sticking a test piece on a steel plate, it was made for the foaming adhesive layer of a test piece to become a steel plate side.

  In Example 1 and Example 2, the loss factor in the frequency region of about 3300 Hz or higher is not measured. The reason for this is that the damping material exhibits sufficient damping performance so that the resonance point of the damping material cannot be found in a frequency region of about 3300 Hz or higher. The vibration damping materials of Example 1 and Example 2 exhibit the same level of vibration damping performance as that in the vicinity of about 3300 Hz even in a frequency region of about 3300 Hz or higher.

  In Comparative Example 3, the loss factor in the frequency region of about 690 Hz or higher is not measured. The reason for this is that the damping material exhibits sufficient damping performance so that the resonance point of the damping material cannot be found in a frequency region of about 690 Hz or higher. The vibration damping material of Comparative Example 3 exhibits the same level of vibration damping as that in the vicinity of about 690 Hz even in a frequency region of about 690 Hz or higher.

(Formability)
The damping material was heated using a far-infrared heater so that the double-sided temperature was 140 ° C. Next, a bottomed cylindrical female die 1 as shown in FIG. 3 is prepared, and the damping material is vacuum-formed using the female die 1 to obtain a flat circular bottom face 21 and A bottomed cylindrical molded product 2 comprising a cylindrical peripheral wall portion 22 extending around the outer peripheral edge of the bottom surface portion 21 in a state orthogonal to the bottom surface portion 21 was obtained. In addition, the vacuum forming of the damping material is such that the thickness of the peripheral wall portion 22 of the molded product 2 is uniform, that there are no cracks or holes in the bottom surface portion 21, the thickness of the bottom surface portion 21 and the thickness of the peripheral wall portion 22. As long as the three conditions are substantially the same, the damping material was vacuum-formed to the maximum extent possible.

Then, the vacuum forming maximum drawing ratio (H / D) is calculated based on the following formula 2 from the diameter D of the outer bottom surface of the molded product and the depth H in which the damping material is vacuum sucked into the female mold. Was used as an index of moldability. The higher the vacuum forming maximum drawing ratio (H / D), the better the damping material is.
Vacuum forming maximum drawing ratio (H / D) = depth H / diameter D: Formula 2

  In Examples 1 to 3, the vacuum forming maximum drawing ratio was 0.8 or more, and all the damping materials had excellent formability. In Comparative Example 1, the vacuum forming maximum drawing ratio is 0.50, and with this formability, the damping material cannot be accurately formed into a shape along the mold shape. The damping materials of Comparative Examples 2 and 3 were inferior in moldability, and holes were immediately formed in the bottom portion, and could not be vacuum formed at all.

(Soundproof)
The sound insulating property of the damping material was measured based on JIS A1416 and used as a soundproofing index. Specifically, the damping material was attached to the opening for attaching the damping material having a square shape of 600 mm on one side opened in the partition door between the sound source room and the reverberation room, and the opening was completely closed. Thereafter, a sound of 90 dB was generated from the sound source in the sound source room, and the loudness A was measured in the reverberation room using a sound level meter (trade name “Precision Sound Level Meter NA-27” manufactured by RION).

Next, without attaching the damping material to the opening for attaching the damping material, the sound volume B is measured in the same manner as described above with the opening fully opened, and the following formula The sound insulation was calculated based on 3.
Sound insulation (dB) = (sound volume B) − (sound volume A) Equation 3

It is the longitudinal cross-sectional view which showed the damping material of this invention. It is the graph which showed the loss coefficient measured in the Example and the comparative example. It is the schematic cross section which showed the measuring point of the moldability of a damping material.

Explanation of symbols

1 Female mold 2 Molded product
21 Bottom
22 Peripheral wall A Damping material B Thermoplastic resin foam sheet C Foam adhesive layer

Claims (7)

A foamed pressure-sensitive adhesive layer is laminated and integrated on one surface of a thermoplastic resin foam sheet containing an inorganic compound, and the inorganic compound is 30 to 100 parts by weight of the thermoplastic resin constituting the thermoplastic resin foam sheet. A vibration damping material containing 300 parts by weight. The vibration damping material according to claim 1, wherein the thermoplastic resin constituting the thermoplastic resin foam sheet is a polyolefin resin. The damping material according to claim 1 or 2, wherein the inorganic compound is a metal salt of an inorganic acid. The damping material according to claim 1 or 2, wherein the apparent density of the thermoplastic resin foam sheet containing an inorganic compound is 0.1 to 0.8 g / cm ³ . 5. The inorganic compound is contained in an amount of 75 to 250 parts by weight with respect to 100 parts by weight of the thermoplastic resin constituting the thermoplastic resin foam sheet. Damping material. The damping material according to any one of claims 1 to 5, wherein the inorganic compound is barium sulfate. The vibration-damping material according to any one of claims 1 to 6, wherein the foamed pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive.

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