JPS5865343A - Vibro-isolating material - Google Patents

Abstract

PURPOSE:To improve vibro-isolating performance of a vibro-isolating material in low and intermediate frequency ranges further decrease weight of the material, by limiting stress of the vibro-isolating material at 25% compression to a specific range further limiting ratio of the stress and specific gravity to a specific range. CONSTITUTION:A foam-state vibro-isolating material, a material of light weight, is used, and stress of the material, when compressed by 25%, is arranged between 1g/cm<2> or more and 60g/cm<2> or less, especially in case of improving vibro-isolating quality in a low frequency range, the stress is arranged to 30g/ cm<2> or less, here ratio of the stress and specific gravity is arranged between 5g/cm<2> and 1,500g/cm<5>, especially in case of aiming at a low frequency range, the ratio is arranged to 10-600g/cm<2>. Then the method of manufacturing the vibro-isolating material is not specially limited, for instance, an urethane foaming material is foamed by the one-shot method. In this way, vibro-isolating performance in a frequency 1,000Hz or less can be improved, while its dependability on temperature can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foam-like damping material having an excellent damping performance of 1iT, and more particularly to a foam-like damping material whose damping performance has been significantly improved in the low and medium frequency range. and
Not only does it have excellent damping performance, but it also has excellent sound absorption performance. A blend of graphite, mica, and carbon added to a resin or thermosetting resin is used, and as a matter of course, it is a material with a high density, ie, a large weight. Due to this σJ, as a result of the increased need for vehicle noise countermeasures in recent years, the damping performance has been improved by 40% due to the development of lightweight damping materials. There is a general rule that the damping performance increases in proportion to the power of %, that is, if the weight is divided by % and 8, the damping performance becomes % and %, respectively.
[Japan Blue Tatami Materials Association - Noise countermeasures]
4c44p] In the case of conventional vibration damping materials, it was extremely difficult to use them as lightweight vibration damping materials.

On the other hand, polyurethane foam, which is a typical lightweight material, has rarely been used as a vibration damping material due to its low damping performance. This is essentially due to the low damping performance of the polyurethane itself, and it is clear that the density becomes extremely low due to the foaming and foaming. In fact, the present inventors evaluated the vibration damping performance of a general commercially available 7-ohm product during research on the present invention, and found that:
The vibration damping performance of polyurethane foam is generally at a low level, and the performance is particularly poor in the low and medium frequency ranges below 7000H1. ■ A large frequency dependence appears in the vibration damping performance.

We discovered the heavy J19 phenomenon.

By the way, as is well known, the oscillation frequency of many devices and equipment that require noise countermeasures is 7,000 Hz or less [Noise Countermeasures Handbook, Chapter 1, P N/?
/P), zoo Nto if possible.

There is a strong demand for noise reduction in the low and medium frequency range below Hz.

It is natural that general commercially available polyurethane foam is of little use in meeting such requirements, as mentioned above, and therefore, a vibration damping material based on polyurethane foam material 1 has the potential to not only improve the overall vibration distribution performance but also It is essential to improve the allocation performance, especially in the low and medium frequency ranges.

As a result of intensive research aimed at these goals, the stress (M!, ), specific gravity (d), and ratio of the two (M fin/d) of 7 ohm material during 2S compression were determined. [Excellent in low and medium frequency range by limiting T to a specific range 21111
1! In terms of performance, it has excellent overall vibration damping performance7.
It was discovered that it is possible to obtain an omega-shaped damping material.Furthermore, the damping performance of conventional damping materials rapidly decreases as the temperature increases, so the temperature range for which they can be used is very narrow. The 7-ohm-like distribution material has a small temperature dependence of damping performance.
Therefore, it is a material that provides excellent distribution effects over a wide temperature range from low temperatures to considerably high temperatures.

Another advantage of the foam damping material of the present invention is that, in addition to the above-mentioned excellent vibration allocation performance, it also has the property of having excellent sound absorption performance in the low and medium frequency ranges. That is, although conventional polyurethane foam has a sound absorption effect in the high frequency range, it has a drawback that the sound absorption effect is very small in the low and medium frequency range, which is the most important frequency range for construction sites. The uninvented 7-ohm shape distribution material has greatly improved this drawback, and is an advantage that should be noted as a practical vibration-damping and sound-absorbing material.

By the way, as is well known, it has become a well-established theory that in order to implement comprehensive and effective noise countermeasures, it is essential in many cases to have both vibration damping and sound absorption effects. . For this reason, when used as a commercially available polyurethane foam pipe sound absorbing material, as mentioned above, the vibration damping performance is particularly low in the low and medium frequency range ['! As a practical solution, a solid damping material (sheet) is laminated onto polyurethane foam to form a composite material, thereby providing vibration damping and sound absorbing performance.

Therefore, in the case of a foam damping material that has excellent vibration allocation performance and sound absorption performance by itself, as in the present invention, there is no need for an expensive damping sheet, and the complicated manufacturing process associated with the combination of the above. Since the vibration damping material made of the foam material used in the present invention can be compressed by % Stress at time (M,)
is 6097- or less, preferably 6097- or less, preferably 300/Cd or less, and vibration damping properties in the low frequency range [J 09/c to improve
d or less is desirable. However, Mu tl' / 9/cd
If it is less than T, the rebound modulus of the foam will be too low to serve as a foam. Also, Mll is 409/C
If it exceeds al, the desired vibration damping performance cannot be obtained. The specific gravity (d) of the foam is 002 or more, Q! or less, preferably
Furthermore, similar to QO Ko 3, if the specific gravity of the 0 form, which is preferably asow or lower, is less than 8T, even if its modulus is small, the expression of damping performance will be small.On the other hand, if the specific gravity is too large, the stress will be high and T 71 #l It's across the street.

Therefore, the ratio of stress (M, ) to specific gravity (d) (M- or low,
The above M is an important parameter for obtaining excellent allocation performance in the medium frequency range. , d, the value of Mn/d is greater than 2g/-*<1,10009
/cd, but generally M ms/d is s-
i, zooy7ci, more preferably j ~/0
009/l:d (FJ range 111 KaJ: Iot
'1: 41fF &-1O when focusing on the low shoulder and neck area
NA 009/ad is appropriate. The foam-like damping material of the present invention, whose stress, specific gravity, and both JktM%) are within the above-mentioned limits, has the following characteristics in terms of damping performance and sound absorption performance. As expected, the foam-like allocation material exhibits frequency dependence,
When the loss coefficient (da), which is a measure of the size of the allocation performance, is plotted against frequency, there is one or more frequencies that give the maximum value. more preferably t
It is below 00kh. On the other hand, regarding sound absorption performance, in order to have excellent sound absorption performance in the low and medium frequency range, the air permeability in the JO thickness must be 1 to 39 cc/c.
j・viscera, preferably 1 to l Q Cc/ci・must be in the true range.

By satisfying the above conditions, it has both excellent vibration damping performance and sound absorption performance in the low and medium frequency range. Any method may be used to obtain the heptagonal partitioned material of the present invention. For example, in the case of a foam material made of polyurethane foam, in terms of composition, a plasticizer such as 7% talate ester 11S-containing octagen fine phosphoric esters (polymer C polyol having terminal hydroxyl groups) is added to the normal polyurethane raw material. It is also possible to add 9 0 to 1 JO weight islands per 100 weight islands or blend a mono- or difunctional polyol. Furthermore, among the usual polyurethane raw materials, for example, one method is to reduce the amount of water to 3 to 30 parts by weight or less based on the amount of polyol, or to reduce the amount of water by a few seconds to more than 10% from the normal value. It is decided. Of course, there is no compromise in combining these compositional properties.

The polyol may be either ether type or ester type, with ether type being more advantageous in terms of cost. Then, such a polyurethane foam raw material is foamed by a method commonly known in the field of polyurethane foam production, such as the one-spot method and the prepolymer method. Further, if necessary, a suitable filler, a colorant, etc. may be added for foaming.

The foam damping material of the present invention can be used for vehicles, ships, automobiles,
As a sound-absorbing and sound-absorbing material for aircraft, etc., as well as for walkway rails, home appliances, metal processing machines, etc., as well as for buildings such as residences, offices, and factories, as well as office equipment,
It is widely used as an allocation and sound absorbing material for computers, audio systems, etc. And this allocation material is 7
It can be used not only in its ohmic shape, but also as a composite material bonded to a metal plate such as an iron plate.Next, the present invention will be explained in more detail based on examples.

Examples 1 to 8, Comparative Example 1 A 0-thickness fin specimen of the foam-like distribution material given in Table 117 and a commercially available polyurethane foam was pasted on an iron plate of 1-thickness to serve as a test specimen. Vibration analysis device (mechanical impedance method) [111 uses! (3
Figure 1 shows the results of determining the loss coefficient (0°C).

Comparative Example 1, which has a fairly high stress (M,), has a low i value at low and medium frequencies, whereas Examples 1 to 8, which have a low stress (M-) and a small Mu/d value, have a low i value at low and medium frequencies. It is clear that the frequency (fsiax) that gives the maximum value of T is below 1000 Hz, and that the value of the low and medium frequency range increases accordingly.

Table I *Comparative Example 1 is a commercially available polyurethane foam.

Note that the air permeability was measured using Dow's Airf Measuring Device Model D.

Example Meeting, b1 Comparative Example 2 The results of measuring 20wz thick specimens of the 7-ohm distribution material given in the m2 table and commercially available polyurethane foam in the same manner as in the previous example are shown in IIJ9. However, in the case of commercially available polyurethane foams with large M and /d values, the f wax is in a fairly high frequency range, and the η value in the low and medium frequency ranges is quite low. Also, in such cases, the air permeability becomes large and the medium frequency sound absorption coefficient is low.

Compared to these, Examples 4 and 5 have a high l value from low to medium frequency range to high frequency range (O@211) *Comparative Example 2 is a commercially available polyurethane foam.

Example 6 M visit= / J g/(Mumeko/d-410ri1011
1. Air permeability=:IQcc/cd-wt, fm*x=!
A foam-shaped distributed material (Example 6) having a physical property value of r00HN and a slightly lower composition than water index:
10wx thickness test results measured using the method described above [5th VT
It is clear that the temperature dependence of the Da value is very small since the Glue value is plotted against the frequency at the measured temperatures of 30°C and 70°C.

Example 2 Sound pressure level reduction effect of specimen.

7 ohm-shaped ceramic material of Example 2 (00 thickness)? 2: Sound pressure level when attached to a steel plate (1m thick) and vibrated [Ill is determined and compared with the case of only one steel plate. This is an IN4 diagram. Frequency dependence of loss coefficient (+7) (11th/)
Correspondingly, it can be seen that the sound pressure l level decreases significantly, indicating that the foam-like distribution material can be an excellent soundproofing material.

Sound Absorption Coefficient of Samples of Example 2 and Comparative Example 2 Using the 011111 thick samples of Example 8 and Comparative Example 2, the sound absorption coefficient was measured by attaching them to a rigid wall using the normal incidence method at room temperature (30°C). As shown in FIG. 5, it can be seen that Example 2 has significantly improved sound absorption coefficient in the low and medium frequency ranges compared to Comparative Example 2. When the air permeability increases as a result of increasing Mu/d as in Comparative Example 2, the sound absorption coefficient becomes extremely low in the low and medium frequency ranges.

As described above, the 7-ohm vibration damping material of the present invention has excellent sound absorption performance, and it can be seen that it is a new sound insulation material that has both vibration damping performance and sound absorption performance.

44. Brief description of the drawings II/Figures to Recitation 3 Figures show the frequency dependence of the loss coefficient (+7) in the foam-like distribution materials of Examples 1 to 6 and Comparative Example I The effect of reducing the sound pressure level by pasting the sample of Example 2, and the 11°C figure is a T graph showing the normal incidence sound absorption coefficient of the sample of Example 2 and Comparative Example 2. Toyo Co., Ltd.

Claims (1)

[Claims] Stress (M,) at 3% compression of saw is 1971d or more, 4
09/Cd or less, and the above stress (Mn) is 4! :specific gravity(
d) the ratio (Mas/d) is S-9/Cd or more,
iro. A damping material made of 7 ohm material with a resistance of 9/C1l or less. The air permeability of the foam material at 20w5N is ~/, 70 CO/re.Claim No. 7
Allocated materials listed in section.