JPS6042476A - Sheet-form vibration damper - Google Patents

Abstract

PURPOSE:To provide a sheet-form vibration damper having excellent vibration damping properties and sound absorptivity over a wide temperature range, consisting of a fibrous material and a resin compsn. consisting of a styrene/acrylate ester copolymer and a vinyl acetate polymer. CONSTITUTION:30-400pts.wt. vinyl acetate polymer composed of 100pts.wt. vinyl acetate and 0-45pts.wt. other copolymerizable monomer such as ethylene is blended with 100pts.wt. styrene/acrylate ester copolymer composed of 100pts.wt. styrene and 50-400pts.wt. acrylate ester to obtain a resin compsn. 80-10wt% said resin compsn. is added to a slurry obtd. by uniformly dispersing and dissolving a fibrous material such as vinylon and optionally a binder resin such as CMC in water. A sheet is formed from the mixture and dehydrated under vacuum to give a water content which is 0.5-2 times as much as the quantity of the solid content. The dehydrated sheet is then dried at 80-200 deg.C to obtain a sheet- form vibration damper.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel sheet-shaped damping material. More specifically, it is composed of 20 to 90% by weight of a fibrous material and 10 to 80% by weight of a mallet resin composition containing styrene-acrylic acid ester copolymer and vinyl acetate polymer as essential components. The present invention relates to a sheet-shaped vibration damping material that has not only vibration damping properties but also Cζ sound absorption properties.

Traditionally, we have been manufacturing vehicles, ships, automobile parts, suppressors, various types of scraping machinery,
In order to prevent vibrations on the surface of structural members such as building materials and acoustic materials, and the noise that accompanies them, the members themselves are made thicker or the equipment itself is improved.1J
Some attempts have been made to prevent this by using vibration-damping materials. Such vibration-damping materials are made by pasting or coating sheet-like, film-like, or paint-like materials on the surface of structural members (substrates) to an appropriate thickness, thereby suppressing the expansion and contraction caused by bending vibrations of the substrate. A non-restrictive damping material that absorbs vibration energy, and a viscoelastic layer on one side of the base material (laminated around the middle,
Furthermore, there are two types of restraint-type vibration damping materials that have a multilayer structure by laminating a restraint layer with a high elastic modulus on the viscoelastic layer, and absorb vibration energy through stretching deformation and shear deformation caused by bending vibration. Are known. Conventionally, compositions for non-restrictive vibration damping materials that have been disclosed include compositions consisting solely of polymers such as rubber, asphalt, synthetic Bd emulsions, and latex, which have the viscoelastic properties of the polymers themselves. There are some that take advantage of these properties, and some that are made by filling polymers with inorganic powders such as graphite, mica, vermiculite, calcium carbonate, talc, and clay, increasing mechanical hysteresis and internal 5ffA, and so on. Compositions for restrained type i'lll1l vibration materials include, for example, those whose main components are copolymers of autovinyl acid and diester maleate, vinyl chloride and ethylhexyl acrylate, etc.
(Japanese Patent Publication No. 39-12451), cellular polyurethane or cellular rubber, vinyl acetate, layered vinyl acetate, bituminous material.

Butyl rubber, acrylic resin, coumaron, indene.

Those made of coumaron-indene and styrene-indene resins (Japanese Patent Publication No. 45-34991), those using polyvinyl butyral (Japanese Patent Publication No. 46-5850), and those using polyvinyl formal (Japanese Patent Publication No. 46-1197).
No. 5), those whose main component is an acidic copolymer of ethylene and an α/β-monoethylenically unsaturated carboxylic acid in which 5 to 25 wt% of nocarboxylic acid groups are neutralized to 0 to 50% with metal ions (special Publication No. 1354 of 1972), one consisting of a copolymer of acrylonitrile and styrene and a plasticizer (Japanese Patent Publication No. 1354 of 1983),
No. 22478), etc. are disclosed.

However, many of these conventional products are designed to be used near room temperature, and even though they have high vibration damping performance near "high temperature", they have limited applicability near the temperature range. In a narrow temperature range centered around the center, or in a high temperature atmosphere, it may become soft or its mechanical properties may deteriorate dramatically.
It has the disadvantage of poor heat resistance. -Many of the materials designed to be used in relatively high temperature ranges use thermosetting resins, so they are organic solvent-based or two-component types consisting of a base resin and a curing agent. To become
There were problems with the safety of the work environment and ease of handling. Furthermore, the conventional vibration damping materials that have already been disclosed cannot be expected to have sound absorption properties at all.

On the other hand, sound absorbing materials include porous materials such as glass wool, rock wool, and slag wool, perforated six spring boards, perforated board structures such as perforated asbestos cement boards, perforated hard boards, and perforated aluminum boards. are known, but on the contrary, these cannot be expected to have damping properties at all. In this way, conventional vibration damping materials and sound absorbing materials have contradictory properties,
In order to reduce noise and vibration that actually occur, the current situation is to use individual materials for damping, sound absorption, sound insulation, and vibration isolation by laminating or combining them.

In view of the above-mentioned current situation, the present inventors have already filed a patent application No. 57-6278 as a sheet-like material with sound absorbing and vibration damping properties.
No. 2 and Japanese Patent Application No. 1983-6327, but after that, as a result of intensive studies to develop materials with even better sound absorption and vibration damping properties, the m-female substance 20
~90% by weight and a resin composition containing styrene-acrylic acid ester copolymer and vinyl acetate polymer as essential components 10-80]1fi1% is a vibration damping material having sound absorbing properties. This discovery led to the present invention.

That is, the present invention includes 20 to 90 g amount% of the string-like substance,
fA) Styrene-acrylic acid ester copolymer and (
Bl vinyl acetate polymer is an essential component, and the component (Al
It is a sheet-like vibration damping material having sound absorbing properties, which is composed of a resin composition of 10 to 400 parts by weight of a component Bl to 100 parts by weight.

The excellent effect of the sound-absorbing sheet-like damping material of the present invention is clearly explained by the tan δ of the styrene-acrylic acid ester copolymer, although it is difficult to explain.
(dissipation factor, loss tangent) maintains a good level from low temperature to high temperature range, and tan δ of vinegar-e-vinyl yarn fusion is particularly R.
``It exhibits a high level in the low temperature range, and a synergistic effect between the two is expected.The styrene-acrylic acid ester copolymer, and the vinyl acetate base are uniformly and well-balanced to achieve the desired E'(Young's modulus). , Real'jii Miyako and G'
(Shear modulus of elasticity, real! 2 parts) is estimated to be due to 6) ζ, excellent adhesion to the base material and the constraining layer, etc.

The fibrous materials used in the present invention may be fibers such as rock wool, asbestos, glass fibers, ceramic fibers, alumina fibers, carbon fibers, inorganic fibers such as mixtures thereof, vinylon, rayon, Examples of the material include organic fibers such as acrylic, nylon, polypropylene, polyvinyl chloride, polyester, and mixtures thereof, and materials such as fibers that are a mixture of inorganic fibers and organic fibers. The degree of orientation of the fibrous material within the layers of the sheet-like material is desirably 3 to 80 degrees (preferably 5 to 70 degrees) in order to increase the interlayer strength of the sheet-like material and improve handling properties; .

The styrene-acrylic acid ester copolymer, which is one of the essential components of the resin composition used in the present invention, includes 4-methoxystyrene in addition to styrene.

A styrene component consisting of a lower alkyl or lower alkoxy compound such as 4-methylstyrene or 2-chlorostyrene, or a t/% rogen derivative, and methyl acrylate or ethyl acrylate, usually having about 1 to 10 carbon atoms.

Propyl acrylate, butyl acrylate, acrylic acid 2
- It is a copolymer consisting of an acrylic acid alkyl ester component such as ethylhexyl. The composition ratio of the constituent monomers in the copolymer is 50 to 400 parts by weight of the acrylic acid ester component (preferably,
It is desirable that the amount is 80 to 200 parts by weight, and if it is out of this range, the effect on vibration damping performance will be small. In the above-mentioned copolymer, a third component may be further copolymerized. For example, a monomer having a hydroxyl group, a carboxy group, etc. may be copolymerized, or a monomer such as 2-hydroxyethyl acrylate or 2-hydroxypropyl acrylate may be copolymerized with a styrene-acrylic acid ester component. 100 weight ii (may be copolymerized about 0.5 to 10 parts by weight with respect to part ζζ), J and vinyl acetate J, which is another essential component of the resin composition used in the present invention.
As for the polymer, the composition specific strength of the groove-forming unitary body in the polymer is 2J acetate, which has a single claw strength of SO to 45 parts of vinyl acetate per 100 parts of vinyl acetate. Mention may be made of small monopolymers and copolymers based on vinyl acetate. Here, the monomers for copolymerization include ethylene, acrylic acid, and acrylic acid alkyl ester.

Dibutyl maleate, vinyl chloride, etc. can be used, and the copolymer may contain one or more of these.

The styrene-acrylic acid ester copolymer (Al
The mixing ratio of the resin composition consisting of vinyl acetate polymer (Bl) is 10 parts by weight of component (A) to 100 parts by weight of component (A).
is carried out in an amount of 50 to 400 parts by weight. Outside this range, if the mixing ratio of the vinyl acetate polymer is less than 530 parts, the damping performance in the low temperature range will decrease, and conversely, if it is more than 400 parts, the damping performance in the high temperature + ffi range will decrease. However, a synergistic effect on the vibration damping properties of the styrene-acrylic acid ester combination and vinyl acetate J-based combination cannot be expected.

The sheet-like damping material of the present invention has a fibrous material of 28 to 90%
and resin compositions 10 to 80 containing a styrene-acrylic acid ester copolymer and a hinyl acetate polymer as essential components.
If the eiJmm composition is less than 1 acid m%, the sound absorption property is excellent or the vibration damping property is insufficient, and vice versa (if it is more than ζ80% by weight, it is more Not only does the damping property not improve significantly, but also the sound absorption property tends to decrease, which is undesirable.Furthermore, in the present invention, in addition to the above-mentioned resin composition, a binder containing a thermoplastic resin as a main component is used in combination. Examples of such binders include water-soluble polymers such as polyvinyl alcohol polymers, polyacrylic acid polymers, polyethylene oxide, carboxymethyl cellulose, casein, and starch, polyvinyl acetate, and co-B1 polymers thereof; Examples include emulsion or latex-like resins such as polyvinyl chloride and copolymers thereof, polyacrylic acid esters and copolymers thereof, polyurethane polymers, or mixtures thereof.The amount of the binder is determined depending on sound absorption and vibration damping properties. It is used within a range that does not cause any interference, but it is usually used within a range of 25 folds or less per 100 parts by weight of the fibrous material.

Furthermore, the inclusion of a polyamide epoxy compound in the resin composition used in the present invention inhibits the macro flow of the composition due to crosslinking reaction with the resin compound, and allows the composition to maintain its shape even in a high temperature atmosphere. It is effective and preferable for maintaining low vibration damping properties. This J-type polyamide epoxy compound is an epoxidized polyamide polyamine in which epichlorohydrin is added to a dehydration condensation product of a diamine (e.g. diethylene triamine) containing a secondary amino group in the molecule and a dicarboxylic acid (e.g. adipic acid). I can give an example. The polyamide epoxy compound is usually used in an amount of 0.5 to 400 parts by weight per 100 parts by weight of the styrene-acrylic acid ester copolymer, but 0.
When used in an amount of 5 to 20 parts or more, the polyamide epoxy compound acts as a crosslinking agent;
When used in an amount of 0.00 parts by weight or less, the polyamide epoxy compound acts as a crosslinking agent and at the same time exhibits the effect of widening the effective temperature range of vibration damping performance.

The inclusion of the scale-like inorganic powder in the resin composition used in the present invention means that the scale-like inorganic powder can be used at the usable temperature, although the peak level of Lan δ of the resin composition may be slightly lowered. It is effective because it has the effect of further widening the range and further improving the heat resistance of the resin composition (suppression of flow in an atmosphere at room temperature, reduction of generation of decomposition residue due to removal of spot welding and fusing). The flake diameter and aspect ratio of the flaky-like powder used in the present invention are not particularly limited, but the flake diameter is usually 40μ.
It is preferable that the average aspect ratio is 10 or more, and that the flake diameter is too large. It becomes difficult to incorporate the resin composition into the sorted material. Furthermore, if the flake diameter is too small, the effect of addition on vibration damping performance will be reduced. Moreover, if the stationary average aspect ratio is smaller than 10, the effect of addition on vibration damping performance will be small. The mixing ratio of the scale-like non-8ili powder is not particularly limited, but if it is too large, the effect of addition on vibration damping performance and heat resistance will not increase any further, and the viscosity of the composition will increase. If the amount increases too much, the workability during production decreases, so it is usually preferably 1,500 parts by weight or less per 100 parts by weight of component (A). Among various scaly inorganic powders, mica is preferred from the viewpoint of performance and cost.

The sheet-like control material having sound absorbing properties according to the present invention can be manufactured, for example, by the following method.

First, a certain amount of fibrous material and, if necessary, additives on a platform scale, and a binder whose main component is a water-bathable thermoplastic resin, an emulsion, or a latex-like thermoplastic resin, are added as a crosslinking agent or a molecular aggregation agent for the thermoplastic resin. A slurry stock solution is prepared by uniformly dispersing and dissolving in water together with an agent (polyacrylamide, polyethyleneimine, sodium polyacrylate, etc.). At this point, a surfactant may be added as appropriate to achieve a dispersion effect. Also, at this point, a foam stabilizer may be used to further increase the dehydration efficiency and control the binder m of the sheet material. be able to. Generally, a nonine surfactant is effective as this foam stabilizer, and its action is due to the action of the water-soluble thermoplastic resin, emulsion, or latex-like thermoplastic resin added to the slurry stock solution. The slurry stock solution will foam slightly, but even out the bubbles.
The first dispersion method is to form an appropriate water film during vacuum dehydration to prevent air from escaping, and to keep the dehydration rate constant at all times. Gentle stirring is preferable, and the mixture can be stirred gently using a device such as a heater.
If it is broken, the fibrous material may break or form spherical aggregates, which is undesirable. A resin composition containing a styrene-acrylic acid ester copolymer and a vinyl acetate polymer as essential components and other additives added as necessary is added to the slurry stock solution and mixed to prepare a wet mat as it is. Alternatively, a wet mat prepared from the above-mentioned slurry stock solution may be impregnated with 5 ml of the slurry.

Next, the ζζ slurry KT is transported from the tank using a slurry pump with a structure (N) to prevent the fibrous substances from forming spherical aggregates, but it is transported to the papermaking section by a method of dropping from the top, running or rotating. The material is supplied from a direction having an angle of 5 to 60 degrees, preferably 20 to 45 degrees with the base material on a net-like or porous material, and is formed into a sheet on the base material to produce a sea urchin'throat pine I. To increase the degree of fiber orientation, it is also effective to supply a slurry stock solution that has been disturbed by blowing liquid or gas into the slurry stock solution onto the base material surface.At this point, the base material The white water containing the binder is filtered from the bottom and returned to the slurry preparation tank together with the white water from the dewatering process to be reused.The obtained wet mat is then dehydrated using the pressure method. .

Conventionally, in fields such as rock wool ceiling materials and asbestos slate boards, this process involves a (roller) press, which requires the same amount of water as dewatering.
14j gives a thick and thin 31'1 roll, surface smoothness, or surface pattern, but it is necessary to produce the sheet material used in the present invention (the roller fujiless method does not have the desired light weight). Sheet-like materials with good bending properties are especially useful.
The most suitable dehydration method is vacuum dehydration. Paper that contains about 5 to 8 times more water than solids? The li T& wet mat is sent to the decompression zone either alone or together with the substrate, and after the internal moisture is sucked out from one or both sides, it is sent to the drying zone. If the dehydration rate is increased, the drying process can be shortened and it is economical, but the sheet will become stale and the specific gravity will increase, so it is preferable to limit the final moisture content to 0.5 to 2 times. In this process, the fine air bubbles inside work effectively to prevent the sheet from sagging and to increase the dehydration rate. The reason for this is thought to be that the water film formed between the fibers prevents air from blowing through from the holding part.

The dehydrated mat is dried by an appropriate method to form a sheet. The drying method can be any of the hot air tray method, hot air blowing method, hot roller contact method, etc.
The appropriate temperature for drying & 1 roll is 80 to 200°C. A resin composition containing a styrene-acrylic acid ester copolymer and a vinyl acetate polymer as essential components and other γ3g additives added as necessary is added to the slurry stock solution from the beginning,
When mixed, the sheet-like material can be used as a damping material that has sound absorbing properties as it is. However, in order to make a damping material that has sound absorbing properties by impregnating the sebum composition afterwards, the following example is used. Mix the styrene-acrylic acid ester copolymer and the vinyl acetate polymer in a 1° emulsion uniformly using the method described above, and add an antifoaming agent, thickener, water, polyamide epoxy compound, and scales as necessary. The sheet is immersed in a resin composition containing an inorganic powder and its brightening agent, and after the sheet is sufficiently impregnated, it is squeezed through rollers until it has a predetermined resin composition, and then heated on a hot air rack. A sheet-like product is obtained by drying using methods such as a drying method, a hot-air tray method, a heated roller contact method, etc.Furthermore, the sheet-like product is dried by forming a wet sheet made of an organic fibrous material on one or both sides of the sheet-like product. It may be a composite sheet-like product having an auxiliary layer formed by.The # layer is made from a wet sheet of pulp, cellulose, or synthetic m fiber, which does not have a fixed form as a layer when used alone. It is formed by combining and drying, and is usually
U, UO + ~ 0.2 times the weight of the sheet, eye oil" 6 ~
5 tl Q/nf' (in the case of one side).Furthermore, the inside or surface number ζ of the sheet-like object is used.
, corner, paper, cheesecloth, non-woven fabric, net, film or gold J!
14 Sheet form of foil etc? fti reinforcement may be used in a composite integrated manner. The reinforcing material only needs to have a thickness that is useful for reinforcing the sheet-like article, and is preferably as thin as possible in terms of back suction performance.

The sheet-like damping material according to the present invention, which has sound absorbing properties, can be used as a non-restrictive damping material by attaching it to a structural member (= J -), and can also be used as a restraining damping material. It is also possible to have flexibility, heat insulation, dew resistance,
It has excellent durability, cushioning properties, etc., and by making use of these characteristics, it is used in civil engineering, dyeing, and printing.
Acoustics, furniture, kitchen equipment, rIL calculation equipment, automatic Elf,
It can also be widely used in lead ships and other industrial fields. Specifically, ζζ is the air conditioner L1, such as a blower duct. + Gold RT4 plates for hoppers, conveyors, soyutes, etc., engine areas, ceilings, floors of marine vessels, automobiles, etc., agricultural υF, civil engineering tractors, lawn mower engines, refrigeration 1 (LI and Part of the piping and compressor of the heating and cooling excavator.

Kitchen utensils and building materials such as the casing and surface of the alley calculator, stainless steel sink, 11J square, roof panel, I9 on the first floor behind the door, acoustic equipment such as acoustic diaphragms, speakers and boxes, as well as factory lung sounds and fathers. In general, soundproofing panels such as metal plates are widely used to prevent noise and vibration, and by pasting them on these or adding a restraining layer to create a multilayer structure, noise can be prevented. It can prevent solid vibration and airborne sound.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Examples 1, 2.3 Comparative Examples A, B 1 s of water, o o o i Placed part ζζ Resin composition consisting of styrene-acrylic acid ester copolymer and vinyl acetate polymer (solid content 50% by weight) 2 , 6LILLl stop part,
and 180 parts of rock wool granular cotton are added,
Gently stir for 30 minutes to disperse and prepare a slurry stock solution.The slurry stock solution is transported in fixed amounts to the papermaking section using a positive displacement rotary pump, and is run diagonally.
A slide-shaped guide plate installed at an angle of 60 degrees with respect to a 0-mesh stainless steel wire mesh is used to guide the flow down and form a 1ζ paper onto the wire mesh. This wet mat is passed between two rollers with a predetermined gap to improve surface smoothness and thickness unevenness by Ii%, and is then sent to a vacuum dehydration saw for dehydration, and finally to a heated side at 150°C. By drying from both sides for 20 minutes in step 1, the thickness is 5-54 m.
A sheet-like material with F+, apparent density of 0.156 to u, 624y, and Ml was obtained.

The angle of the fibrous hook in the layer of this sheet material was 14 degrees. The proportion of the resin composition contained in the fibrous material was adjusted by varying the degree of vacuum dehydration. , MJ fat composition formulation The ratio C of the paralysis resin composition is shown in Table 1.

Table 1 Note 1) The results of the absorption rate α measured by the normal incidence method in a tube for a sheet material containing a styrene-difunctional tylhexyl acrylate copolymer (polymerization ratio l l) resin composition are shown in Table 1. (The air layer on the back surface was 4.5 parts m in both cases, and the temperature was 20° C.).

Furthermore, the loss coefficient was measured using the vibrating lead method (cantilever beam, resonance method) by pasting it on a cold rolled steel plate (thickness 1.0 mm).
The results are shown in Table 2. (It is said that a damping material must have a loss coefficient of 0.05 or more.) ) Table 2 The sheet-shaped vibration damping materials according to the present invention exhibit comparable values for both sound absorption coefficient and loss coefficient, and have both excellent sound absorption and vibration damping properties, whereas those not according to the present invention have excellent sound absorption and vibration damping properties. was never able to have both.

Example 4.5.6 Comparative Example U, IJ Water + 8. Carboxyl-modified ethylene-hinyl acetate co-emulsion (
Glass transition Lu 10” (:, solid content SLl 1I 11%
) 130 product S, 5 parts of nonionic interfacial agent bath e (pressure reduction 10 weight) consisting of polyoxyethylene nonylphenol ether J, polyacrylic acid bath as coagulant (n agricultural side) 0.2. True Mi 7i%) 1
Add 10% of dissolved Pr' (Sase), and further add 180% of rock wool granular cotton, stir gently for 50 minutes to disperse, and make a slurry stock solution.Execute from the slurry stock solution. Using the same method as Example 1.2.3 and Comparative Examples A and B, the thickness was 5.0 ml+, and the apparent density g O, 120.
The sheet-like material of Y7ci is I4. The binder content of this sheet-like material was 5.0% by weight of the total weight of the sheet-like material, and the degree of orientation of the fibrous material within the layer was 15 degrees. The sheet-like material was immersed in the persimmon fat resin and the composition 11 shown in Table 3 to impregnate it with the resin composition, and then passed between the rollers to form an impregnated star of 9%. (Squeeze it so that it swings,
A sheet-shaped imitation material was prepared by drying the sheet for 60 minutes from one side with hot air of ζ 150"C.

The back absorption rate of these sorted damping materials is 0 at 100011Z.
．． It showed a value of 7 to 10, indicating good absorbency (back chamber %T14.E>cm).

γ7I of loss coefficient; 1 degree dependence (ζ is shown in FIG. 2).

The sheet-shaped vibration damping material according to the present invention shows a value of 118 from low temperature to arm degree, whereas the material not based on the present invention ζζ has a large temperature dependence or a long loss duration. ;2 <, Good (If it was; it was different from the material.

Note 43 Styrene-acrylic 1112-functional tylhexyl A
m-copolymer (copolymerization ratio 23) Note 5) Ethylene-vinyl acetate copolymer (containing 1% ethylene 11) Note 6
5UZORITE MICA (iftM average flake diameter 90 pm, ff Using vinylon fibers with a thickness of 1.0 denier and a fiber length of 5 to 12 M1°C, a sorted material consisting of organic fibers with JI of 4 and 5.0 was obtained, and Example 4.5. The sheet was impregnated with the resin composition in the same manner as in step 6, then squeezed between rollers to achieve the desired impregnation level, and finally dried for 60 minutes at an art dealer with hot air at 150°C. Even with 1ζ, the same results as in Example 4.5.6 and IJ were obtained (Example 7.8.9). 1 m+ #l!: 8 sheets of non-woven fabric (mesh size 96 gytrl) were impregnated with a resin composition in the same manner as in Example 4.5.6. Almost the same results as in Examples 4, b, and 6 were also obtained (Examples 10, 11, and 12) 1.

[Brief explanation of drawings]

Figure 1 shows the frequency dependence of the sound absorption coefficient measured by the 'r: 1 Uchiza 10 human method C? Yuri. 1]
It is a figure showing the temperature dependence of a lapse coefficient. In the figure, vinegar numbers 1 to 6 correspond to Examples 1 to 6, respectively, and symbols A-a JJ correspond to ratio 1 yield example A-1), respectively.
do. Patent Applicant: Kuraray Co., Ltd. Patent Attorney Ken Honda No. 1 Illustration Suzuki Number (H2)

Claims (3)

[Claims] (1) 20 to 90% by weight of fibrous material, (Al styrene-acrylic ester copolymer and (hinyl acetate polymer) as essential components, and the component (component tB to A1100ii parts) is 30 to 400% by weight. A sheet-shaped vibration damping material comprising 10 to 80% of a resin composition mixed in a proportion of 10% to 80%. (2) The styrene-acrylic acid ester copolymer contains styrene + ooxm portion of niacrylic acid ester from 50 to 400.
The sheet-like damping material according to claim (1), which is a copolymer composed of multiple buttocks. (3) Claim (1) or (2) wherein the vinyl acetate polymer is a polymer composed of 100 parts by weight of vinyl acetate and 0 to 45 parts by weight of a copolymer monomer. Sheet-shaped vibration damping material as described in section.