JP2974920B2 - Silencer pad for car floor - 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 as a composite vibration damping material for automobile floors (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).

[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 automobile floors where surface pressure is applied, the seat will quickly fall and the density will increase, and the spring constant will increase. And the effect of vibration isolation is eventually lost.

Accordingly, an object of the present invention is to provide a composite vibration damping material for automobile floors 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. In particular, it is an object of the present invention to provide a silencer pad for an automobile floor, which does not increase the density or the spring constant due to the sagging of the seat and maintains the effect of vibration insulation.

[0006]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies, and as a result, oriented the main fiber made of thermoplastic synthetic resin and the binder fiber almost perpendicularly to the sheet surface. It is, and is obtained by heat-sealed fibers, density 0.01~0.045g / cm ^3, Pas
When the pad thickness is 10 to 20 mm, the dynamic spring constant is 0.
The sheet-like fibrous structure of 1 × 10 ^{6 to} 0.5 × 10 ⁶ N / m is excellent in resilience even when a surface pressure is applied and has little set, so that the density does not increase and the frequency is 500 Hz or less. It also has an effect on vibration damping in a low frequency range, and has been found to be suitable as a silencer pad for an automobile floor.

The present invention has been completed on the basis of the above findings, and has a main fiber made of a thermoplastic synthetic resin and a binder fiber oriented substantially perpendicularly to the sheet surface, and the fibers are thermally fused to each other. sheet-like fibrous structure Tona comprising Te
Pad, wherein the density of the fibrous structure is 0.01 to
0.045 g / cm ³ , pad thickness 10-20 mm
Dynamic spring constant is 0.1 × 10 when the ^{6 ~0.5} × 10 ⁶ N
/ M. Hereinafter, the present invention will be described in detail.

The silencer pad for an automobile floor according to the present invention comprises a main fiber made of a thermoplastic resin and a binder fiber, and the binder fiber has a melting point lower than that of the thermoplastic synthetic resin which is a component of the main fiber by 20 ° C. or more. It is preferable to use a sheath-core composite fiber having a thermoplastic resin as a sheath component and a thermoplastic resin of the same type as the main fiber as a core component. The reason is that by heating the fiber structure to a temperature that is equal to or higher than the melting point of the sheath component of the binder fiber and lower than the melting point of the core component, the fibers easily fuse with each other. As a preferable combination of such a main fiber and a binder fiber, when the main fiber is a crystalline polypropylene, the binder fiber has a low melting point copolymer in which the main component of the monomer is propylene as a sheath component, A sheath-core composite fiber having a core component of a high melting point polymer made of crystalline polypropylene is preferable.

When the main fiber is a high-melting polyester having a melting point of 200 ° C. or higher, the binder fiber has a high-melting polyester of the same kind as the main fiber as a core component and has a melting point lower by at least 20 ° C. than the melting point of the core component. A sheath-core composite fiber having a low melting point copolyester as a sheath component is preferred. 200 melting point
Polyethylene terephthalate and polybutylene terephthalate are preferably used as the high-melting polyester having a temperature of not less than ° C. As the low-melting copolyester, a copolymer component is added to the acid component side and / or glycol component side of 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. Examples of the copolymerization component on the acid component side include carboxylic acids such as isophthalic acid, trimellitic acid, and adipic acid, and the copolymerization components on the glycol component side include diethylene glycol, triethylene glycol, and polyethylene glycol. And polyols such as polypropylene glycol.

The main fiber and the binder fiber may contain various additives such as a coloring agent, a flame retardant, a deodorant, an antibacterial agent, and a stabilizer, if necessary.

In the silencer pad for an automobile floor according to the present invention, the main fibers and the binder fibers are oriented substantially perpendicular to the sheet surface, and the fibers are thermally fused to each other.

Here, that the binder fibers of the main fibers are oriented substantially vertically means the following state. That is, since the main fiber and the binder fiber are crimped, they are relaxed and bent, which means that straight fibers are arranged in parallel in a direction perpendicular to the sheet surface. Rather, it means that the fiber arrangement direction is relatively uniform in the direction perpendicular to the sheet surface. FIGS. 1 and 5 show specific examples in which the main fibers and the binder fibers are oriented substantially vertically.

FIG. 1 is a perspective view of a foldable pad. One example of a method of manufacturing the foldable pad is as follows.
A method in which the main fiber and the binder fiber are mixed, the web obtained by using a card machine is folded into a corrugated shape, and then hot-air fusion is performed.

FIG. 5 is a perspective view of the upright pad. As an example of a method of manufacturing the upright pad, there is a method of cutting off the folded portions on the upper and lower surfaces of the foldable pad shown in FIG.

Further, the main fiber and the binder fiber wound on the bobbin are cut vertically, and both cut surfaces are heat-sealed.
After arranging the obtained fiber structure so that both cut surfaces thereof are positioned vertically, by applying compression repeatedly from the upper part to promote the spread of the fiber structure in the horizontal direction,
Upright pads can also be obtained.

Further, an upright pad can be obtained by orienting the fibers in a vertical direction by performing needle punching on a fibrous structure formed of a main fiber and a binder fiber, which is formed into a mat shape.

Orienting the main fiber and the binder fiber substantially perpendicularly to the sheet surface as described above is an important component in the silencer pad for an automobile floor according to the present invention. There is no increase in density and no increase in spring constant due to settling, and the effect of vibration isolation is maintained.

In the fibrous structure constituting the silencer pad for an automobile floor according to the present invention, the dynamic spring constant is :
When the pad thickness is 10 to 20 mm , 0.1 × 10 ⁶
It is limited to 0.5 × 10 ⁶ N / m. The reason is,
If it exceeds 0.5 × 10 ⁶ N / 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, the dynamic spring constant is 0.1 × 1
When the 0 less than ⁶ N / m, substantially in the density is very small, on the pad itself is not at the level which can be produced stably, because an obstacle in machining process to acoustic insulation in combination with other materials It is. In addition, the above-mentioned pad thickness 1
0 to 20 mm is the condition for limiting the range of the dynamic spring constant
And a silencer pad for an automobile floor according to the present invention.
Is not limited to 10 to 20 mm.

The density of the fibrous structure constituting the silencer pad for an automobile floor of the present invention is 0.01 to 0.045.
g / cm ³ . The reason is that the effect of the pad density on the soundproofing performance in the action of attenuating solid vibration is that the smaller the density, the greater the vibration damping effect. However, if the density is less than 0.01 g / cm ^3, as described above. This is because the density is too small and it is impossible to stably produce such a low-density pad. On the other hand, 0.0
If it exceeds 45 g / cm ³ , the dynamic spring constant of the pad becomes 0.5
This is because it exceeds × 10 ⁶ N / m, and the vibration damping effect is not obtained. The density is particularly preferably from 0.013 to 0.
020 g / cm ³ .

As for the mixing ratio [B / (A + B)] of the main fiber (A) and the binder fiber (B), if the mixing ratio is low, the number of bonding points in heat fusion is very small, and the pad having a small dynamic spring constant is used. Is obtained, but the completed pad is
Since the fluff of the fiber is easily generated and the strength is low, 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.

[0021] Then the ratio of the main fiber thickness of _(A) (D A) and the thickness of the binder fiber _(B) (D B) (denier ratio: D
_A / D _B ) increases when D _A increases and when D _B decreases. When D _B is constant and D _A increases, the number of heat fusion points decreases. Therefore, the strength of the pad decreases, and when D _A is constant and D _B decreases, the number of heat fusion points increases, and the strength of the pad increases.

As described above, the structure of the pad (density, the mixing ratio (B / (A + B)) of the main fiber (A) and the binder fiber (B), the thickness (D _A ) of the main fiber and the binder Table 1 summarizes the relationship between the fiber thickness (D _B ) and the pad performance (dynamic spring constant, vibration level, strength, and resilience).

[0023]

[Table 1]

The silencer pad for an automobile floor according to the present invention is excellent in light weight, excellent in silence, vibration damping and soundproofing by combining a polyvinyl chloride sheet, a polyvinyl chloride sheet having air holes and a recycled cotton felt. This makes it possible to obtain a composite vibration damping material for an automobile floor which is excellent in quality.

[0025]

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 ],
4. The thickness of the pad will be described later. 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 vibration jig is randomly vibrated by a vibrator, and the frequency of the primary resonance point is measured by an accelerator pickup attached to the center of the polyvinyl chloride sheet, and the dynamic spring constant (k) is calculated by the following equation. 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 The sample was placed on a 1.6 mm-thick steel plate vibration plate fixed to a fixed frame, and the vibration plate was vibrated. Then, the vibration level of the upper surface of the skin layer of the vibration plate and the soundproof material was measured, and the vibration level (X) was calculated by the following equation. Vibration level (X) = log (vibration level X ₂ in skin layer) −log (vibration level X _{0 of} steel sheet)

4. 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.

5. 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 folding pad) The following were used as the main fiber (A) and the binder fiber (B). Main fiber (A) Single type polypropylene fiber Raw material: UBE Polypro ZS1276 (homopolymer) Fiber length: 76 mm, single yarn: 23 de, number of crimps: 10 / inch Binder fiber (B) Sheath-core type composite fiber Sheath material: Showa Denko TD750 (ethylene-
Propylene binary random copolymer) Core material: UBE Polypro ZS1276 (homopolymer) Fiber length 51 mm, single thread 4 de, crimp number 15 / inch

The main fiber (A) and the binder fiber (B) are mixed so as to have a mixing ratio of [B / (A + B) × 100] = 35%, and a uniform web having a basis weight of 125 g / m ² is applied to a carding machine. Produced. Next, the web was folded into a wave shape, and the web was heated at a hot air temperature of 145 ° C. for a residence time of 1 hour.
The main fiber and the binder fiber are heat-fused through a hot-air fusing machine under the conditions of minutes, and the thickness is 15 mm and the density is 0.017 g / cm.
To obtain a ^third pad. FIG. 1 shows a perspective view of the obtained folding pad. Table 2 shows various performances of the obtained foldable pad. From Table 2, the dynamic spring constant (E ') is 0.1
The vibration level was 8 × 10 ⁶ N / m, the vibration level was 19.6 dB, and the recovery rate was 63%. It was clear that the vibration damping property and the sag resistance were excellent. MD tensile strength is 5.5kg / 5c
m, and it was also clarified that if the material had such strength, there would be no problem in the process of combining it with other materials to form a composite vibration damping and soundproofing material.

[0034] Next, as shown in FIG. 2, a thickness of 15 mm, the pad 1 having a basis weight of 255 g / m ^2, a thickness of 1.5 mm,
Basis weight 2330 g / m ² of polyvinyl chloride (PVC) sheet 2, a thickness of 1.5 mm, basis weight 2290 g / in m ^2, polyvinyl chloride having a vent (PVC) sheet 3 and a thickness of 10 mm, basis weight 430 g / m ² A composite vibration-damping and sound-insulating material was manufactured by combining with the recycled cotton felt 4 of No. 1, and the vibration level was measured. The result is shown in FIG. As is clear from FIG. 3, the composite vibration damping material using the pad of Example 1 is a sound damping material (a 1.5 mm thick PVC sheet 2 and a 20 mm Recycled cotton felt 4, 2 mm thermosetting resin sheet 5, 3
The vibration level was remarkably attenuated over a wide range as compared with the asphalt sheet 6 having a thickness of 6 mm.
Moreover, the composite vibration damping material of Example 1 weighs 11.69 kg / m ² to 5.3 in comparison with the currently used sound damping material.
It could be reduced to 1 kg / m ² .

Example 2 (Polypropylene Upright Type Pad) First, a folded pad as shown in FIG. 1 was produced in the same manner as in Example 1. The thickness of the obtained pad is 30 mm
This is the only difference from the first embodiment in which a pad having a thickness of 15 mm is obtained.

The folded portions of the upper and lower surfaces of the obtained pad were cut off to obtain a pad (Example 15) (thickness: 15 mm, density: 0.017 g / m ² ) in which the constituent fibers were almost upright.
FIG. 5 shows a perspective view of the obtained upright pad. Table 2 shows various properties of the obtained upright pad. According to Table 2, the dynamic spring constant E ′ was 0.25 × 10 ⁶ N / m, the vibration level was 22.0 dB, and the recovery rate was 73%, and the vibration damping property and the set resistance were excellent. In addition, as shown in FIG. 5, a web boundary surface which cannot be visually recognized remains in the pad thus manufactured. Since there is no fiber connection at this interface, the tensile strength in the direction corresponding to the MD before resection is 1.5 kg / 5 cm, whereas in the direction corresponding to the CD, the fiber has a tensile strength of 5.5 kg / cm. 5 cm. As described above, although the strength in the MD direction is low, it has also been clarified that there is no problem in the process of combining with another material to form a composite vibration damping soundproofing material.

Next, Example 1 was performed using the obtained pad.
2 and the vibration level was measured in the same manner as in Example 1. As a result, the vibration level was attenuated over a wide range as in Example 1. It became clear.

The composite vibration damping material of Example 2 was as light as 5.31 kg / m ² .

Example 3 (Polyethylene terephthalate foldable pad) A foldable pad as shown in FIG. 1 in the same manner as in Example 1 except that the following were used as the main fiber (A) and the binder fiber (B). Pads were made. Main fiber (A) Single type polyethylene terephthalate fiber Material: K101 manufactured by Kanebo K101 Fiber length: 76 mm, single yarn: 20 de, number of crimps: 9 / inch Binder fiber (B) Sheath-core type composite fiber Product name: Unitika ) Made Melty fiber length 51mm, single yarn 4de, number of crimps 12.6 pieces / inch

Table 2 shows various performances of the obtained foldable pad.
Shown in From Table 2, the dynamic spring constant (E ') is 0.19 × 1
0 ⁶ N / m, the vibration level 20.1DB, recovery rate 68%
It was clear that the material had excellent vibration damping and sag resistance. The MD tensile strength was 5.3 kg / 5 cm, and it was clarified that there was no problem in the process of combining with other materials to form a composite vibration damping soundproofing material.

Next, Example 1 was performed using the obtained pad.
2 and the vibration level was measured in the same manner as in Example 1. As a result, the vibration level was attenuated over a wide range as in Example 1. It became clear. The composite vibration damping material of Example 3 was as light as 5.31 kg / m ² .

Example 4 (Polyethylene terephthalate-based upright pad) The same as Example 2 except that the same polyethylene terephthalate-based material as used in Example 3 was used as the main fiber (A) and the binder fiber (B). By the method, an upright pad as shown in FIG. 5 was obtained. Table 2 shows various properties of the obtained upright pad. From Table 2, the dynamic spring constant (E ') is 0.27 × 10 ⁶ N / m, the vibration level is 23.2 dB,
The recovery rate was 75%, which proved to be excellent in vibration damping property and sag resistance. MD tensile strength is 1.4kg
/ 5 cm, but it was also clarified that there would be no problem in the process of combining with other materials to form a composite vibration damping soundproofing material.

Next, Example 1 was performed using the obtained pad.
2 and the vibration level was measured in the same manner as in Example 1. As a result, the vibration level was attenuated over a wide range as in Example 1. It became clear. Further, the composite vibration damping material of Example 4 was as light as 5.31 kg / m ² .

[0044]

[Table 2]

[0045]

As described above, according to the present invention, there is provided a silencer pad for an automobile floor which is not only lightweight but also has little settling even when a surface pressure is applied and has excellent resilience. Then, using the silencer pad, a composite vibration-damping and sound-insulating material for an automobile floor, which is excellent in lightness, vibration damping, and soundproofing, was provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a silencer pad of the present invention.

FIG. 2 is a cross-sectional view of a composite vibration damping material incorporating a silencer pad of the present invention.

FIG. 3 is a graph showing a vibration level of the soundproofing material.

FIG. 4 is a cross-sectional view of a current soundproofing material.

FIG. 5 is a perspective view showing another example of the silencer pad of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Silencer pad 2 PVC sheet 3 PVC sheet having ventilation holes 4 Recycled cotton felt 5 Thermosetting resin sheet 6 Asphalt sheet

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI D04H 1/54 D04H 1/54 H 1/70 1/70 A G10K 11/162 G10K 11/16 A (72) Inventor Shin Ota Next 2-1-1, Yabuta Nishi, Gifu City, Gifu Prefecture Inside Ube Nitto Kasei Co., Ltd. (72) Inventor Yutaro Kasai 2-1-1, Yabuta Nishi, Gifu City, Gifu Prefecture Ube Nitto Kasei Co., Ltd. (56) Reference Document JP-A-7-160269 (JP, A) JP-A-64-77666 (JP, A) JP-A-6-184902 (JP, A) JP-A-1-221234 (JP, A) JP-A-7-160 223478 (JP, A) Hikaru 4-127291 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B60R 13/08

Claims (6)

(57) [Claims] 1. A main fiber made of a thermoplastic synthetic resin and a binder fiber are oriented substantially perpendicular to a sheet surface,
And one sheet-like fibrous structure obtained by heat fusion fibers
A pad comprising a fiber structure having a density of 0.0
1-0.045 g / cm ³ , pad thickness 10-20
The dynamic spring constant when mm is 0.1 × 10 ^{6 to} 0.5 × 1
Silencer pads for automobiles floor, which is a 0 ⁶ N / m. 2. The binder fiber, wherein the sheath component is a thermoplastic resin having a melting point lower by at least 20 ° C. than the thermoplastic synthetic resin that is a component of the main fiber, and the core component is a thermoplastic resin of the same type as the main fiber. Item 4. A silencer pad for an automobile floor according to Item 1. 3. The main fiber is a crystalline polypropylene fiber, and the binder fiber is a low melting point copolymer having a main component of propylene as a sheath component, and a high melting point polymer made of crystalline polypropylene is a core component. The silencer pad for an automobile floor according to claim 1 or 2, which is a sheath-core type composite fiber. 4. A sheath-core type composite fiber in which a main fiber is a polyester fiber having a melting point of 200 ° C. or higher, and a binder fiber is 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. The silencer pad for an automobile floor according to claim 1 or 2, wherein: 5. A composite vibration damping material for an automobile floor, comprising the silencer pad according to claim 1 as an essential member. 6. A composite vibration damping material for automobile floors, comprising a combination of the silencer pad according to claim 3 and a polyvinyl chloride sheet, a polyvinyl chloride sheet having ventilation holes, and recycled cotton felt.