JP3347253B2 - Automotive silencer pad - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer pad preferably used for a composite vibration damping material for automobiles (a sound damping material in which a vibration damping material, a sound insulating material, and a sound absorbing material are combined).

[0002]

2. Description of the Related Art Conventionally, a sheet-like structure made of anti-haired felt or various fibers has been used as a silencer pad in a composite vibration damping material for automobiles. In recent years, automobiles have been required to have improved fuel efficiency and comfort. One of the comforts is quietness, which is generally said to increase as the weight of the soundproofing material used increases. However, when the weight increases, the improvement in fuel efficiency cannot be achieved. Therefore, a soundproofing material having a large soundproofing effect even if it is lightweight is desired. Soundproofing materials in the cabin of an automobile are basically divided into two types depending on the use site. One is a soundproofing material used for parts that are hardly subjected to surface pressure such as doors, ceilings, dashboard panels,
This is a soundproofing material used in areas where surface pressure is applied, such as floor panels.

[0003] The present applicant has proposed that a crystalline polypropylene is used as a main fiber, and a sheath component composed of a low-melting-point polymer whose main component is propylene and a high-melting-point polymer that is a crystalline polypropylene as a binder fiber. Using a sheath-core type composite fiber obtained by compounding with a core component, and a silencer pad formed by arranging these fibers in parallel to the sheet surface, as a soundproofing material used in a portion where surface pressure is hardly applied, It has been found that the silencer pad is suitably used in place of an asphalt sheet (vibration damping material), and a patent application has been filed for this silencer pad (Japanese Patent Application No. 5-306)
863, JP-A-7-160269).

[0004]

However, in the silencer pad of the patent application, most of the fibers forming the pad (a kind of sheet-like fiber structure) are oriented parallel to the sheet surface. Therefore, it is effective in reducing weight and improving quietness.However, if this is used as it is for a composite vibration damping material for automobiles where surface pressure is applied, the sheet gradually decreases and the density increases, and the spring constant also increases. There is a problem that the vibration insulation becomes large and the effect of vibration insulation is eventually lost.

In general, in order to prevent an increase in density or an increase in spring constant due to sheet sagging, it is necessary to increase the rigidity of the fibrous structure. However, when the rigidity of the fibrous structure is increased, a new problem arises in that the effect of vibration insulation is reduced and the sound insulation performance in a low frequency range is reduced.

Accordingly, an object of the present invention is to provide a composite vibration damping material for automobiles which has advantages such as light weight and quietness, solves the drawbacks of the silencer pad described in the above-mentioned patent application, and applies surface pressure. Another object of the present invention is to provide a silencer pad for an automobile which does not increase the density or the spring constant due to the set of the sheet, maintains the effect of vibration insulation, and has higher sound absorbing and insulating performance.

[0007]

The first silencer pad (I) of the present invention for achieving the above object comprises a main fiber (A) made of a thermoplastic synthetic resin, a binder fiber (B), and a fine fiber ( C) and fold it into a corrugated web
It is folded to orient each fiber substantially perpendicularly to the sheet surface, and is made of a sheet-like fiber structure obtained by heat-sealing the fibers, and the density of the fiber structure is 0.010 to 0.0
50 g / cm ³ , dynamic spring constant is 0.1 × 10 ^{6 to} 0.5
× 10 ⁶ N / m.

[0008] The second silencer pad (II) for achieving the above object is a main fiber (A) made of a thermoplastic resin.
And the binder fiber (B) into a mixed cotton web
A fibrous structure obtained by folding in a wave shape and orienting each fiber substantially perpendicular to the sheet surface is arranged in the upper layer, and the binder fiber (B) and the fine fiber (C) are formed into a mixed cotton web in the lower layer. It is made of a sheet-like fibrous structure in which fibers are heat-sealed and integrated after being laminated, and the density of the fibrous structure is 0.020 to 0.050 g / cm ³ and the dynamic spring constant is 0. .1 × 10 ^{6 to} 0.5 × 10 ⁶ N / m.

Further, a third silencer pad (III) for attaining the object of the present invention is characterized in that a main fiber (A) made of a thermoplastic resin and a binder fiber (B) are made into a mixed cotton web and the binder fiber is formed on the upper surface. A sheet-like fiber obtained by blending (B) and the finely divided fiber (C) into a cotton web and arranging it on the lower surface, orienting the fiber substantially perpendicular to the sheet surface, and thermally fusing the fibers to each other. A fibrous structure having a density of 0.020 to 0.055 g / c.
m ³ , the dynamic spring constant is 0.1 × 10 ^{6 to} 0.5 × 10 ⁶ N /
m.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The vehicle silencer pad (I), (II),
(III) comprises a main fiber (A), a binder fiber (B), and a fine fiber (C), each of which is made of a thermoplastic resin, and the binder fiber (B) is a component of the main fiber (A). It is preferable to use a sheath-core composite fiber in which a thermoplastic resin having a melting point lower than that of a certain thermoplastic synthetic resin by 20 ° C. or more is used as a sheath component, and a thermoplastic resin of the same type as the main fiber (A) is used as a core component. The reason is that the fiber structure is converted to
By heating to a temperature higher than the melting point of the sheath component and lower than the melting point of the core component, the fibers easily fuse with each other. Such a main fiber (A) and a binder fiber (B)
When the main fiber (A) is a crystalline polypropylene, a preferable combination with the binder fiber (B)
It is preferable to use a sheath-core composite fiber having a low-melting-point copolymer in which the main component of the monomer is propylene as a sheath component and a high-melting-point polymer made of crystalline polypropylene as a core component.

The fine fiber (C) has a fineness of 1/50 to 1/5 of the fineness of the main fiber (A), and is made of a thermoplastic resin component of the same type as the main fiber (A). preferable. The reason is that if the fineness of the fine fiber (C) exceeds 1/5 of the fineness of the main fiber (A), the fiber diameter is too large to increase the resistance of air passing through the pad, and as a result The sound energy cannot be absorbed efficiently. If the fineness of the fine fiber (C) is less than 1/50 of the fineness of the main fiber (A), the mixing property when producing a fiber structure is significantly reduced, and as a result, the yield is reduced in a normal card machine. It becomes worse and industrial production becomes difficult.

A preferred combination of the main fiber (A), the binder fiber (B), and the finely divided fiber (C) is such that when the main fiber (A) is crystalline polypropylene, the binder fiber (B) Is preferably a sheath-core composite fiber having a low-melting-point copolymer in which the main component of the monomer is propylene as a sheath component, and a high-melting-point polymer made of crystalline polypropylene as a core component. Crystalline polypropylene is preferred.

When the main fiber (A) is a high-melting polyester having a melting point of 200 ° C. or higher, the binder fiber (B) has a high-melting polyester of the same type as the main fiber (A) as a core component, and A sheath-core composite fiber having a low melting point copolyester having a melting point lower than the melting point by 20 ° C. or more is preferable, and the fine fiber (C) is a high melting point having a melting point of 200 ° C. or more of the same kind as the main fiber (A). Polyester is preferred. Polyethylene terephthalate and polybutylene terephthalate are suitably used as the high melting point polyester having a melting point of 200 ° C. or higher. As a low melting point copolyester,
A polyester which is a polycondensate of an acid component composed of terephthalic acid and a glycol component composed of ethylene glycol, propylene glycol or butylene glycol, wherein a copolymer component is added to the acid component side and / or the glycol component side, and the acid component Examples of the copolymer component on the side include isophthalic acid, trimellitic acid, carboxylic acids such as adipic acid, and the copolymer component on the glycol component side include:
Examples include polyols such as diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol.

The main fiber (A), the binder fiber (B) and the fine fiber (C) may contain various additives such as a coloring agent, a flame retardant, a deodorant, an antibacterial agent and a stabilizer, if necessary. Can be contained.

In the automotive silencer pad (I) of the present invention, the main fiber (A), the binder fiber (B), and the fine fiber (C) are substantially perpendicular to the sheet surface in a folded state. And the fibers are thermally fused to each other.

Here, that the main fiber (A), the binder fiber (B), and the fine fiber (C) are oriented substantially perpendicularly means the following state. That is, main fiber (A), binder fiber (B), and fine fiber (C).
Is crimped, so it is relaxed and bent, so it does not mean that straight fibers are arranged in parallel in the vertical direction to the sheet surface, but the arrangement of fibers This means that the directions are relatively uniform in the direction perpendicular to the sheet surface. FIG. 1 shows a specific example in which the main fiber (A), the binder fiber (B), and the finely divided fiber (C) are oriented almost vertically.

As an example of a method for manufacturing the folded single-layer pad shown in FIG. 1, a web obtained by mixing a main fiber (A), a binder fiber (B), and a fine fiber (C) with a card machine is used. Is folded in a corrugated shape and then hot-air-fused.

The automobile silencer pad of the present invention (I
In (I), a fibrous structure in which the main fibers (A) and the binder fibers (B) are oriented almost perpendicularly to the sheet surface is arranged in the upper layer, and the binder fibers (B) and the fine fibers are arranged in the lower layer. The fibers are heat-sealed after the fiberized fibers (C) and the fiberized fibers (C) are made into a mixed cotton web to form a multilayer. 2 and 3
FIG. 1 shows a typical example of the folded multilayer silencer pad (II) of the present invention.

As an example of a method for manufacturing the folded multilayer silencer pad (II) shown in FIGS. 2 and 3, a main fiber (A) and a binder fiber (B) are mixed, and a web obtained by a card machine is waved. After folding into a mold, there is a method in which the binder fiber (B) and the finely divided fiber (C) are mixed with the lower layer, and a web formed into a sheet by a card machine is multi-layered, followed by hot air fusion.

The silencer pad for an automobile of the present invention (II)
In (I), a mixture of a main fiber (A) made of a thermoplastic synthetic resin and a binder fiber (B) is formed into a mixed cotton web, and a binder fiber (B) and a finely divided fiber (C) are mixed into a mixed web. After arranging the fibers on the lower surface, the fibers are oriented substantially perpendicular to the sheet surface, and the fibers are heat-sealed.

FIGS. 4 and 5 show a typical example of the laminated folding pad (III) of the present invention. As an example of a method for manufacturing the laminated foldable pad (III) shown in FIGS. 4 and 5, a main fiber (A) and a binder fiber (B) are mixed, and the resulting web is made into a sheet-like web by a card machine. Mixed with binder fiber (B) and fine fiber (C)
There is a method of laminating sheet-shaped webs on a card machine, folding the webs into a corrugated shape, and fusing with hot air.

FIG. 6 is a cross-sectional view of a laminated folded multi-layer pad which is one embodiment of the pad (III) of the present invention. As an example of a method of manufacturing the laminated folded multi-layer pad,
There is a method in which a binder fiber (B) and a fine fiber (C) are further blended in the lower layer of the laminated foldable pad shown in FIG. 4, and a sheet-like web is multi-layered by a card machine, followed by hot-air fusion. .

As described above, in the silencer pad (I) of the present invention, it is important to mix the main fiber (A) and the binder fiber (B) together with the finely divided fiber (C) and then to orient the fiber substantially vertically. It is a configuration requirement.

Further, in the silencer pads (II) and (III) of the present invention, the fine fiber (C) and the binder fiber (B) are added to the vibration insulating layer composed of the main fiber (A) and the binder fiber (B). It is an important constituent requirement that the sound absorbing layer consisting of a plurality of layers is formed on the upper and lower layers or laminated on the upper and lower surfaces. The sound absorbing performance can be improved without increasing the weight of the pad while maintaining the effect of vibration isolation.

In the present invention, a pad (I) having a single layer structure
By increasing the weight of the pad, the sound absorption performance can be improved.
g / m ² or less, a non-woven fabric made of fine fibers or a film having a thickness of 100 μm or less can be bonded to the pad surface, and one or both surfaces of the pad are melted by a hot roll or the like to increase the density. You can also. In addition,
Similar measures can be taken for the silencer pads (II) and (III).

Further, the cross-sectional shapes of the main fiber and the finely divided fiber can be further improved by setting the cross-sectional shape to an irregular shape other than the circular shape. The irregular cross section mentioned here includes a cross section of a convex polygon such as a flat or a triangle, or a concave polygon such as a Y-shape, a cross or a star.

The fiber composite constituting the silencer pads (I), (II) and (III) for automobiles of the present invention has a dynamic spring constant of 0.1 × 10 ^{6 to} 0.5 × 1.
0 is limited to ⁶ N / m. The reason is 0.5 × 10 ⁶ N
If it exceeds / m, the resonance peak cannot be reduced with a pad having a thickness of 10 to 20 mm, and the pad layer needs to be further thickened, resulting in a problem that the interior space of the vehicle becomes narrow. On the other hand, when the dynamic spring constant is less than 0.1 × 10 ⁶ N / m, the density is substantially very low, the pad itself is not at a level at which it can be stably manufactured, and the pad is combined with other materials for soundproofing. This is because there is a problem even in the processing step for the material.

The density of the fiber composite constituting the silencer pad for automobiles of the present invention is determined by the silencer pad (I)
0.020 to 0.050 g / cm ³ , in the case of silencer pad (II), 0.020 to 0.050 g / cm ³
cm ³ , 0.020 for silencer pad (III)
It is limited to ０．０５0.055 g / cm ³ . The reason is that the effect of the pad density on the soundproofing performance in the action of attenuating solid vibrations is that the lower the density, the greater the vibration damping effect, but the pads (I), (II) and (III)
In the case where the density of the fiber composite is less than the respective lower limit, the density is too small, and it is impossible to stably produce such a low-density pad. Dynamic spring constant of 0.5
This is because it exceeds × 10 ⁶ N / m, and the vibration damping effect is not obtained. Further, the density of the fiber composite is determined by the pad (I)
In the case of 0.015 to 0.040 g / cm ³ , the pad (I
For I), 0.025~0.040g / cm ^3, when the pad (III), preferably a 0.025~0.045g / cm ^3.

The mixing ratio of the binder fiber (B) [B / (A
+ B + C)], when the mixing ratio is reduced, a pad having a very small number of adhesion points in heat fusion and a small dynamic spring constant can be obtained, but the finished pad is liable to generate fiber fuzz and has low strength. Therefore, there is a problem in a process of combining with another material as a soundproofing material. On the other hand, when the mixing ratio is increased, the number of bonding points is increased and the strength of the pad is increased, but the dynamic spring constant is also increased. Furthermore, the cost increases because the binder fiber is a composite fiber composed of two components unlike the main fiber. Therefore, it is desirable to reduce the mixing ratio as much as possible in consideration of the operability during processing.

The mixing ratio of the fine fiber (C) [C / (A + B)
+ C)], when the mixing ratio is low, sufficient sound absorbing performance cannot be obtained, and when the mixing ratio is increased, the rigidity of the fiber structure becomes insufficient, and the effect of preventing sagging decreases, and the density increases. As a result, the vibration insulation is reduced. Therefore, the mixing ratio of the fine fiber (C) is 20 to
Desirably, it is 60%.

[0031] Next, the fineness of the main fiber fineness of _(A) (D A) and binder fibers _{(B) (D B),} D in D _B is constant
_{As A} increases, the number of heat-bonding points decreases, and the strength of the pad decreases. When D _A is constant and D _B decreases, the number of thermal bonding points increases. , The spring constant increases, and the vibration insulation property decreases.

The ratio of the fineness (D _A) of the size of the fine繊化fiber _(C) (D C) as a main fiber (A) (denier ratio: D _C / D _A)
In this case, if it exceeds 1/5, there is a problem that it is not possible to sufficiently impart sound absorbing properties. On the other hand, if it is less than 1/50, there is a problem that fibers cannot be sufficiently mixed, resulting in poor cotton mixing. Therefore, a preferable ratio is 1/50 to 1
/ 5, more preferably 1/30 to 1/8.

As described above, the structure of the pad (density, mixing ratio of binder fiber (B) [B / (A + B +
C)], fine fiber mixing ratio [C / (A + B + C)]),
Fineness of main fiber (D _A ), fineness of binder fiber (D _B ),
Table 1 summarizes the relationship between the fineness (D _C ) of the finely divided fiber and the performance of the pad (dynamic spring constant, vibration level, strength, resilience, sound absorption).

[0034]

[Table 1]

The silencer pads (I), (II) and (III) for automobiles according to the present invention are excellent in light weight, excellent in silence, vibration damping and soundproofing by combining a polyvinyl chloride sheet, floor carpet and the like. A composite vibration damping material for automobiles having excellent properties can be obtained.

[0036]

EXAMPLES The present invention will be described in detail below with reference to examples, but before that, various measuring methods will be described.

1. Density Pad weight [g] ÷ Pad apparent volume [cm ³ ] In calculating pad apparent volume [cm ³ ],
The thickness of the pad will be described later in 6. The initial thickness determined from the recovery rate (sag resistance) was adopted.

2. Dynamic spring constant An aluminum plate having a thickness of 10 mm is used as a substrate, and this is fixed to a vibrating jig. A pad is placed on the substrate, and a polyvinyl chloride sheet (3 kg / m ² ) of the same size is further placed thereon. The entire vibrating jig is randomly vibrated by a vibrator, and the frequency of the primary resonance point is measured by the acceleration pickup attached to the center of the polyvinyl chloride sheet and the aluminum plate. The dynamic spring constant (k ) Was calculated. k = (2πf) ² × m [N / m] f: frequency of primary resonance point [Hz] m: surface weight of polyvinyl chloride sheet [kg · m ⁻² ]

3. Method of Measuring Vibration Level A steel plate having a thickness of 1.6 mm is used as a substrate, which is fixed to a vibration jig. The soundproof material of the sample is placed on the substrate, and the whole vibration jig is randomly vibrated by a vibrator. The vibration level (dB) of the skin layer at the frequency of the primary resonance point was measured by an acceleration jig attached to the vibration jig and the skin layer of the soundproofing material.

4. Measurement method of average sound absorption coefficient The measurement was performed based on the standing wave method (A pipe was used for the main pipe) in JIS A 1405 “Method of measuring normal incidence sound absorption coefficient of building materials by pipe method”. Specifically, in the frequency range of 250 to 2000 Hz, the frequency (250, 315,
400, 500, 630, 800, 1000, 125
At 10 points of frequency of 0, 1600 and 2000 Hz), the ratio of the maximum value and the minimum value of the sound pressure of the standing wave generated in the main pipe (standing wave ratio: n) is measured, and the sound absorption at each frequency is calculated by the following equation. The rate (α ₀ ) was calculated. The calculated sound absorption coefficient for each frequency was added, and a value divided by 10 was defined as an average sound absorption coefficient. α ₀ = [4 / (n + 1 / n−2)] × 100

5. Tensile strength Measured in an atmosphere of 20 ° C. and 65% RH at a width of 50 mm, a chuck interval of 100 mm, and a tensile speed of 200 mm / min. As shown in FIG.
The direction and the CD direction were determined.

6. Recovery Rate (Sag Resistance) A test piece of 300 × 300 × 15 mm was placed on a flat table and pressed from the upper surface of the test piece with a circular pressure plate having a diameter of 200 mm. As a preload, 4.9 N (0.5 kgf) ) Is measured, and this is defined as the initial thickness.

Next, a 147 N (15 kg)
The load of f) is applied for 11 hours in an atmosphere of 50 ° C. and 95% RH, then the load is removed, the thickness after 1 hour is measured, and the recovery rate (%) is obtained from the following equation. Recovery rate (%) = (thickness 1 hour after load release) / (initial thickness) × 100

Example 1 (Polypropylene-based folded single layer)
Mold pad) The following were used as the main fiber (A), the binder fiber (B), and the finely divided fiber (C). Main fiber (A) Single type polypropylene fiber Raw material: Y2000GP (homopolymer) manufactured by Idemitsu Petrochemical Co., Ltd. Fiber length 76 mm, single yarn 25 de, number of crimps 10 / inch Binder fiber (B) Sheath-core type composite fiber Sheath Raw material: TD750 (Ethylene-produced by Showa Denko KK)
(Propylene binary random copolymer) Core material: Y2000GP (homopolymer) manufactured by Idemitsu Petrochemical Co., Ltd. Fiber length: 51 mm, single thread: 4 de, number of crimps: 15 / inch Fine fiber (C) Single type polypropylene fiber Raw material : UBE Polypro RS1238 (Homopolymer) Fiber length 51mm, Single yarn 2de, Number of crimps 20 / inch

The mixing ratio (A) / (B) / (C) of the main fiber (A), the binder fiber (B) and the fine fiber (C) is 32.5 / 35 / 32.5. The mixture was mixed in the same manner as described above, and processed by a card machine to produce a uniform web having a basis weight of 55 g / m ² . Next, the web was folded into a corrugated shape, and the web was passed through a hot-air fusing machine under the conditions of a hot air temperature of 145 ° C. and a residence time of 1 minute to thermally fuse the main fiber, the binder fiber, and the finely divided fiber, A pad having a basis weight of 500 g / m ² , a thickness of 20 mm, and a density of 0.025 g / cm ³ was obtained. FIG. 1 shows a perspective view of the obtained folded single-layer pad. Tables 2 and 3 show various performances of the obtained folded single-layer pad.
From Tables 2 and 3, the dynamic spring constant (E ′) is 0.18 ×
10 ⁶ N / m, vibration level 19.6 dB, recovery rate 63
% And an average sound absorption coefficient of 20%, which proved to be excellent in sound absorption while maintaining vibration damping and sag resistance.
The MD tensile strength was 5.5 kg / 5 cm, and it was clarified that the presence of such a strong strength would not hinder the process of combining with other materials to form a composite vibration-damping soundproofing material.

Example 2 (Polypropylene-based folded single layer)
Mold Pad) A folded single-layer pad was obtained in the same manner as in Example 1 except that the basis weight of the folded single-layer pad was 750 g / cm ² . Tables 2 and 3 show various performances of this pad.
From Tables 2 and 3, it was found that by increasing the basis weight, the sound absorbing performance and sag resistance could be improved.

Example 3 (Polypropylene-based folded multilayer)
Mold Pad) FIG. 2 is a perspective view and FIG. 3 is a cross-sectional view of the folded multilayer pad obtained in this embodiment.

First, in the same manner as in Example 1, the main fiber (A) and the binder fiber (B) were mixed so as to have a mixing ratio of 65/35, and a uniform web having a basis weight of 30 g / m ² was prepared using a card machine. 250g /
m ^2, to obtain a low spring vibration insulating layer 1 _AB . Next, the same binder fiber (B) and fine fiber (C) as in Example 1 were used.
Was mixed so as to have a mixing ratio of 50/50, and a uniform web having a basis weight of 500 g / cm ² was prepared using a card machine.
Those formed into a sheet and sound absorbing layer 1 _BC.

After the low-spring vibration insulating layer 1 _AB is arranged on the upper layer and the sound absorbing layer 1 _BC is laminated on the lower layer, the web is heated at 145 ° C. and the residence time is 1 minute. Through which the main fiber, the binder fiber and the fine fiber are heat-fused to give a basis weight of 750 g / m ² , a thickness of 25 mm and a density of 0.
A pad of 030 g / cm ³ was obtained. The density of the upper layer portion of the obtained folded multilayer pad is 0.017 g / cm ³ ,
The density of the lower layer was 0.050 g / cm ³ , and both layers were completely fused. Tables 2 and 3 show various properties of the obtained folded multilayer pad. From Tables 2 and 3,
The dynamic spring constant (E ′) is 0.17 × 10 ⁶ N / m, the vibration level is 18.8 dB, the recovery rate is 78%, and the average sound absorption coefficient is 34.
%, Which proved to be excellent in sound absorption performance while maintaining vibration damping and sag resistance. The MD tensile strength was 7.2 kg / 5 cm, and there was no problem in the process of combining with other materials to form a composite vibration damping soundproofing material.

Example 4 (Polypropylene laminate folding)
Mold Pad) FIG. 4 is a perspective view and FIG. 5 is a cross-sectional view of the folded multilayer pad obtained in this embodiment.

First, the same main fiber (A) and the same binder fiber (B) as in Example 1 were mixed so as to have a mixing ratio of 65/35, and a uniform web having a basis weight of 80 g / m ² was prepared using a card machine. Is a low spring vibration insulating layer _1AB .
Next, the same binder fiber (B) and fine fiber (C) as in Example 1 were mixed so as to have a mixing ratio of 50/50, and a uniform web having a basis weight of 160 g / m ² was prepared using a card machine. It was used as a sound absorbing layer 1 _{B C.}

After the low-spring vibration layer 1 _AB is laminated on the upper surface and the sound-absorbing layer 1 _BC is laminated on the lower surface to form a sheet, the laminated web is folded into a wave shape, and the web is retained at a hot air temperature of 145 ° C. The main fiber, the binder fiber and the fine fiber are heat-fused through a hot-air fusing machine under the condition of time 1 minute,
Weight 750 g / m ² , thickness 25 mm, density 0.030 g
/ Cm ³ pad was obtained. The sound absorbing layer in the obtained laminated foldable pad has a high density (0.050 g / cm ³ ), is oriented almost perpendicular to the sheet surface, and is completely fused, so that it has a set resistance. Can be further improved. Tables 2 and 3 show various properties of the obtained laminated folding pad. From Tables 2 and 3, the dynamic spring constant (E ′) is 0.11 × 10 ⁶ N / m, and the vibration level is 1
It was 1.0 dB, the recovery rate was 82%, and the average sound absorption rate was 27%, which proved to be excellent in vibration damping properties, sag resistance and sound absorption performance. The MD tensile strength was 5.8 kg /
It is also clear that, with such a large depth, there is no problem in the process of combining with other materials to form a composite vibration damping soundproofing material.

Example 5 (Polypropylene-based laminate folding)
(Multilayer pad) FIG. 6 shows a cross-sectional view of the folded multilayer pad obtained in this embodiment.

First, the same main fiber (A) and binder fiber (B) as in Example 1 were mixed so as to have a mixing ratio of 65/35, and a uniform web having a basis weight of 80 g / m ² was prepared using a carding machine. Is a low spring vibration insulating layer _1AB .
Next, the same binder fiber (B) and finely divided fiber (C) as in Example 1 were mixed so as to have a mixing ratio of 50/50, and a uniform web having a basis weight of 80 g / m ² was prepared using a card machine. Was defined as a first sound absorbing layer 1 _BC . The low spring vibration layer 1
The _AB on the upper surface, and after the first sound absorbing layer 1 _BC was then laminated to the lower surface into a sheet, the laminated web basis weight 500 g /
The layer folded in a wave shape at m ² is the upper layer, and the same binder fiber (B) and fine fiber (C) as in Example 1 are mixed at a mixing ratio of 50/50. After forming a uniform web of 250 g / m ² and laminating the second sound absorbing layer 2 _BC in a sheet shape as a lower layer,
The web is passed through a hot-air fusing machine under the conditions of a hot-air temperature of 145 ° C. and a residence time of 1 minute so that the main fibers, the binder fibers and the fine fibers are heat-fused, and the basis weight is 750 g / m ² and the thickness is 25 m.
m, a pad having a density of 0.030 g / cm ³ was obtained. Tables 2 and 3 show various properties of the obtained laminated foldable pad. From Tables 2 and 3, the dynamic spring constant (E ') is 0.1
It was 4 × 10 ⁶ N / m, the vibration level was 13.5 dB, the recovery rate was 80%, and the average sound absorption coefficient was 38%, which proved to be excellent in vibration damping property, sag resistance and sound absorption performance. .

Comparative Example 1 A folded single-layer pad was prepared in the same manner as in Example 1 except that the main fiber (A) was used instead of the fine fiber (C). Tables 2 and 3 show various properties of the obtained folded single-layer pad. From Tables 2 and 3, the dynamic spring constant (E ′) is 0.13 × 10 ⁶ N / m, and the vibration level is 1
2.2 dB, the recovery rate was 63%, and the average sound absorption rate was 11%. The vibration damping property and the sag resistance were good, but the sound absorbing performance was not sufficient.

Comparative Example 2 A folded single-layer pad was produced in the same manner as in Example 3 except that the main fiber (A) was used instead of the fine fiber (C). Tables 2 and 3 show various performances of the obtained folded multilayer pad. From Tables 2 and 3, it can be seen that the vibration damping property and the sag resistance are maintained, but the average sound absorption coefficient is 14%, which is not sufficient.

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

As described above, the automobile silencer pad of the present invention is not only lightweight, but also has little settling even when surface pressure is applied, has excellent resilience, and maintains vibration insulating effects. This has the advantage that the sound absorption is improved. Then, using this silencer pad, a composite vibration damping material for automobiles with excellent lightness, vibration damping properties, and sound insulation properties,
For example, it is possible to provide a composite vibration damping material that is useful when used for a dash panel, a floor panel, and the like.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an example of a silencer pad according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a silencer pad according to a third embodiment of the present invention.

FIG. 3 is a sectional view showing a silencer pad according to a third embodiment of the present invention.

FIG. 4 is a perspective view showing a silencer pad according to Embodiment 4 of the present invention.

FIG. 5 is a sectional view showing a silencer pad according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a silencer pad according to a fifth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Silencer pad 1 _AB low spring vibration insulation layer 1 _BC 1st sound absorption layer 2 _BC 2nd sound absorption layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI G10K 11/16 G10K 11/16 D 11/162 A (72) Inventor Hiroshi Kawase 100 Kanayama, Ichiriyama-cho, Kariya-shi, Aichi Pref. Inside the Auto Body Co., Ltd. (72) Inventor Shinji Ota 2-1-1, Yabuta Nishi, Gifu City, Gifu Prefecture Inside Ube Nitto Kasei Co., Ltd. (72) Masaharu Mimaki 2-1-1, Yabuta Nishi, Gifu City, Gifu Prefecture Ube Nitto Kasei Co., Ltd. (72) Inventor Yutaro Kasai 2-1-1, Yabuta Nishi, Gifu City, Gifu Pref. Ube Nitto Kasei Co., Ltd. (56) References JP-A 7-160269 (JP, A) Kaihei 7-219556 (JP, A) JP-A 4-127291 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60R 13/08 B32B 5/08 D01F 8/06 D04H 1/54 G10K 11/16 G10K 11/162

Claims (13)

(57) [Claims] 1. A main fiber (A) comprising a thermoplastic synthetic resin
Cotton mixing c the binder fibers and (B) and fine繊化fibers (C)
It is made of a sheet-like fiber structure obtained by folding the ebbed into a corrugated shape, orienting each fiber substantially perpendicular to the sheet surface, and heat-bonding the fibers to each other, and the density of the fiber structure is reduced. A silencer pad for automobiles, wherein the pad has a dynamic range of 0.010 to 0.050 g / cm ³ and a dynamic spring constant of 0.1 × 10 ^{6 to} 0.5 × 10 ⁶ N / m. 2. The method according to claim 1, wherein the binder fiber (B) is the main fiber (A).
Is a sheath-core type composite fiber having a thermoplastic resin whose melting point is lower than that of the thermoplastic synthetic resin by at least 20 ° C. as a sheath component, and a thermoplastic resin of the same kind as the main fiber as a core component. C) is 1/50 to 1 with respect to the fineness of the main fiber (A).
The automobile silencer pad according to claim 1, which has a fineness of / 5 and is made of the same thermoplastic resin component as the main fiber (A). 3. A high-conductivity fiber made of a highly crystalline polypropylene, wherein the main fiber (A) is a crystalline polypropylene and the binder fiber (B) is a low melting point copolymer having a main component of propylene as a sheath component. It is a sheath-core type composite fiber having a melting point polymer as a core component, and the fine fiber (C) is a crystalline polypropylene fiber having a fineness of 1/50 to 1/5 of the fineness of the main fiber (A). The automobile silencer pad according to claim 1. 4. The main fiber (A) is made of a polyester fiber having a melting point of 200 ° C. or higher, and the binder fiber (B) is made of a low-melting copolyester as a sheath component and a high-melting polyester of the same type as the main fiber as a core component. A sheath-core type composite fiber,
The fine fiber (C) is 1/50 of the fineness of the main fiber (A)
The automobile silencer pad according to claim 1 or 2, which is a polyester fiber having a fineness of 1/5 and a melting point of 200 ° C or more. 5. A main fiber (A) made of a thermoplastic synthetic resin.
And the binder fiber (B) into a mixed cotton web
A fibrous structure obtained by folding in a wave shape and orienting each fiber substantially perpendicular to the sheet surface is arranged in the upper layer, and the binder fiber (B) and the fine fiber (C) are formed into a mixed cotton web in the lower layer. It is made of a sheet-like fibrous structure in which fibers are heat-sealed and integrated after being laminated, and the density of the fibrous structure is 0.020 to 0.050 g / cm ³ and the dynamic spring constant is 0. A silencer pad for automobiles, characterized in that the thickness is 1 × 10 ^{6 to} 0.5 × 10 ⁶ N / m. 6. The method according to claim 1, wherein the binder fiber (B) is the main fiber (A).
Is a sheath-core composite fiber having a thermoplastic resin whose melting point is lower than that of the thermoplastic resin by at least 20 ° C. as a sheath component, and a thermoplastic resin of the same kind as the main fiber as a core component. ) Is 1/50 to 1/50 of the fineness of the main fiber (A).
6. The automobile silencer pad according to claim 5, having a fineness of 5 and comprising a thermoplastic resin component of the same type as the main fiber (A). 7. A high-conductivity polypropylene made of high-crystalline polypropylene, wherein the main fiber (A) is a crystalline polypropylene, and the binder fiber (B) is a low-melting-point copolymer in which the main component of the monomer is propylene. It is a sheath-core type composite fiber having a melting point polymer as a core component, and the fine fiber (C) is a crystalline polypropylene fiber having a fineness of 1/50 to 1/5 of the fineness of the main fiber (A). The automobile silencer pad according to claim 5. 8. The main fiber (A) is made of a polyester fiber having a melting point of 200 ° C. or higher, and the binder fiber (B) is made of a low-melting copolyester as a sheath component and a high-melting polyester of the same type as the main fiber as a core component. A sheath-core type composite fiber,
The fine fiber (C) is 1/50 of the fineness of the main fiber (A)
The automobile silencer pad according to claim 5 or 6, which is a polyester fiber having a 1/5 fineness and a melting point of 200 ° C or more. 9. A main fiber (A) comprising a thermoplastic synthetic resin.
And a binder fiber (B) are placed on the upper surface, and a binder fiber (B) and the fine fiber (C) are placed on the lower surface. It is made of a sheet-like fiber structure which is vertically oriented and heat-fused with each other, and has a density of 0.020 to 0.055 g / cm ³ and a dynamic spring constant of 0.1 ×. An automobile silencer pad having a density of 10 ^{6 to} 0.5 × 10 ⁶ N / m. 10. The binder fiber (B) has a melting point 20 times higher than that of the thermoplastic synthetic resin which is a component of the main fiber (A).
It is a sheath-core type composite fiber having a thermoplastic resin having a lower temperature of at least ℃ as a sheath component and a thermoplastic resin of the same kind as the main fiber as a core component. The fine fiber (C) is smaller than the fineness of the main fiber (A). 1/5
The automobile silencer pad according to claim 9, which has a fineness of 0 to 1/5 and is made of the same thermoplastic resin component as the main fiber (A). 11. The main fiber (A) is made of crystalline polypropylene, and the binder fiber (B) is made of a highly crystalline polypropylene having a low melting point copolymer whose main component of the monomer is propylene as a sheath component. It is a sheath-core type composite fiber having a melting point polymer as a core component, and the fine fiber (C) is a crystalline polypropylene fiber having a fineness of 1/50 to 1/5 of the fineness of the main fiber (A). The automobile silencer pad according to claim 9. 12. The main fiber (A) is made of a polyester fiber having a melting point of 200 ° C. or more, and the binder fiber (B) is
A sheath-core type composite fiber having a low-melting copolyester as a sheath component and a high-melting polyester of the same type as the main fiber as a core component, wherein the fine fiber (C) is 1/5 of the fineness of the main fiber (A).
The automobile silencer pad according to claim 9 or 10, which is a polyester fiber having a fineness of 0 to 1/5 and a melting point of 200 ° C or more. 13. A binder fiber (B) as a lower layer.
The silencer pad for an automobile according to any one of claims 9 to 12, wherein a layer formed by mixing cotton and a fine fiber (C) into a web is laminated.