JPH01206396A - Damping material - Google Patents

Abstract

PURPOSE:To improve various characteristics such as a mechanical characteristic, durability and formability, etc., by using a polyurethane resin obtained by allowing a specific polyole resin to react with a polyisocyanate compound and specifying a physical property of a damping material whose main component is this resin. CONSTITUTION:The title damping material uses a polyurethane resin obtained by allowing a polyole resin being polyhydric alcohol and/or its polymer to react with a polyisocyanate compound. Also, said damping material is formed so that the maximum value of a loss coefficient eta of the damping material is >=1.3, and tensile rupture strength, tensile rupture elongation and tensile elastic modulus are 0.05-3.0kgf/mm<2>, 20-300% and 0.1-5.0kgf/mm<2>, respectively, compressive strength is >=5kgf/mm<2>, and also, Izod impact strength is >=5 kgfcm/cm. In such a way, even under a high temperature or a high vacuum, a volatile component is small, said material is provided with a stable and excellent damping performance, and also, its mechanical strength, durability and formability are improved.

Description

[Detailed Description of the Invention] The present invention relates to a vibration damping material containing polyurethane resin as a main component. The present invention relates to a vibration damping material that exhibits little change in physical properties when used and has excellent mechanical strength.

l'n<1 view t and 1 problem. 7. In order to prevent the vibrations of the vibration source from being transmitted to other parts, it has been widely practiced to interpose vibration-proof rubber or air springs in the contact area between the vibration source and other parts. However, although these methods can prevent the transmission of vibrations, they cannot be expected to attenuate the vibrations themselves of the vibration source.

For this reason, a method has been adopted in which a damping material is brought into close contact with the vibrating body to attenuate the vibration of the vibrating body itself. Such damping materials reduce vibration by converting vibration energy into heat. It is trying to weaken.

By the way, vibration suppression of a vibrating body using a damping material is achieved by changing the amplitudes of adjacent vibrations in a damped sinusoidal waveform to x, respectively.
x, the logarithmic attenuation rate δ shown by the following formula (1)
The larger the value, the better the vibration suppression effect can be obtained.

δ=In(x1/x2) ·−(i) The logarithmic attenuation rate δ is expressed by the following equation (2) using the loss coefficient η.

δ=πη (2) Therefore, it can be said that a damping material with a larger loss coefficient η has better characteristics.

When actually using such a damping material, there are two methods: one is to simply attach the damping material to the vibration source (non-constraint type), and the other is to insert the damping material between the vibration source and the restraint plate. There are cases where it is used (constraint type).

By the way, in a constraint-type damping material that is used by inserting a damping material between a vibrating body and a restraining plate, the loss coefficient η of the vibrating body is expressed by the following formula (3).
It is approximately expressed by.

E3h 3 31 12・□□ In the formula, E and E3 represent the Young's modulus of the vibrating body and the restraining plate, respectively, h and h3 represent the thickness of the vibrating body and the thickness of the restraining plate, respectively, and h - h +(
h + h )/2, h2 is the thickness of the damping material, η2 is the loss coefficient of the damping material itself, and g is the shear parameter shown by the following equations (4) and (5). be.

However, G is the rigidity of the damping material, and ρ1 is the density of the vibrating body.

From the above equation, it can be seen that the damping material preferably has a large loss coefficient η2 and a small rigidity.

As a vibration damping material, it not only has excellent vibration damping performance as described above, but also has good formability, mechanical strength, water resistance, and chemical resistance, and can be used even at high temperatures or under high vacuum. Something is required.

Conventionally, resins such as polyamide resins, polyvinyl chloride resins, and epoxy resins have been used as materials constituting vibration damping materials for forming such damping materials.

However, damping materials molded from damping material compositions containing polyamide resin as the main component have poor water resistance and chemical resistance, and have low mechanical strength, so the conditions of use are limited. There was a problem. In addition, it is difficult to mold vibration damping materials whose main component is polyvinyl chloride resin into damping materials with complex shapes, and it is also costly to manufacture a wide variety of damping materials in small quantities. There was a problem. Furthermore, when trying to obtain a damping material based on epoxy resin that has high mechanical strength, durability, and moldability, its damping performance is poor; However, when attempting to obtain such a material, there were problems in that the mechanical strength was low, and the durability and moldability were also poor.

By the way, damping materials generally tend to have a large loss coefficient (η) near the phase transition point (glass transition point or melting point). Therefore, for vibration damping materials whose main component is an amorphous resin, it is desirable that the glass transition point of the resin component be near the operating temperature of the damping material. In this way, a method has been adopted in which a plasticizer is added to the resin component to adjust the glass transition point and other properties. That is, since the plasticizer is a low molecular weight organic filler that can lower the glass transition temperature, the glass transition point of the resin component can be adjusted appropriately by blending the plasticizer.

However, when conventional damping materials containing plasticizers are used in environments such as high temperatures or high vacuum,
Even if the damping material is cured, the plasticizer may evaporate and the damping characteristics may change, or the volatilized plasticizer may condense on the surface of other equipment and contaminate the surface. was there. There is a concern that such problems arise even when the damping material is used under normal conditions such as room temperature and pressure.

The present invention is an attempt to solve the problems associated with the prior art as described above, and it can be used not only at room temperature and pressure, but also at high temperature or under high vacuum. It is also an object of the present invention to provide a vibration damping material which has a low volatile content, therefore has stable and excellent vibration damping performance, and has excellent mechanical strength, durability and moldability.

Approximately 1 and 1 The damping material according to the present invention comprises (a) polyhydric alcohol and/or
Or a damping material containing a polyurethane resin obtained by reacting a polyol resin, which is a polymer thereof, and (b) a polyisocyanate compound, the damping material having a maximum loss coefficient η of 1.3. The above is JIS K7113
The tensile strength at break, elongation at break and tensile modulus are
0.05~3.0kgf/stop 2.20~3 respectively
00% and 0.1~5, 0k (if/+w+n2, compressive strength according to JISK6911 is O-5kgf
/nm2 or more, and the Izot impact strength according to JIS K6911 is 5 kgfa++/■ or more.

A vibration damping material according to the present invention uses a polyurethane resin obtained by reacting a specific component (a) with a polyisocyanate compound as a component (b), and has this resin as a main component. Because it has specific physical properties, it has excellent mechanical properties, durability, moldability, and other properties. Furthermore, by using such polyurethane resin, it is possible to reduce the amount of plasticizer used,
Alternatively, since it is not necessary to substantially use a plasticizer, the volatile content is reduced even when used at high temperatures or under high vacuum. Therefore, the vibration damping material of the present invention has stable characteristics.

“Nine dandan and stop sauce” The damping material according to the present invention will be specifically explained below.

The damping material according to the present invention includes either a polyhydric alcohol or a polymer of this polyhydric alcohol as the <a>component;
Alternatively, it includes a polyurethane resin prepared by using a mixture of both and using a polyisocyanate compound as the component (b).

Component (a) used in the preparation of the polyurethane resin used in the present invention is a polyhydric alcohol and a polymer of polyhydric alcohol, and specifically, the compounds shown below can be mentioned.

That is, examples of polyhydric alcohols and polymers of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and 1,2-butylene glycol. , 1.3-butylene glycol, 1.4-butylene glycol, di(1,
4-butylene glycol), poly(1,4-butylene glycol), neobentyl glycol, 1,6-hexanediol, di(6-hydroxyhexyl) ether, 1,8-octanediol, di(8- hydroxyoctyl) ether, 1,10-decanediol di(10-
Polyols having 2 to 15 carbon atoms such as hydroxydecyl) ether, phenylethylene glycol and diphenylethylene glycol; glycerol, polyglycerol and trimethylolpropane; and propylene oxide adducts of pentaerythritol. These can be used alone or in combination.

Examples of the polyisocyanate compound as component (b) used in the preparation of the polyurethane resin used in the present invention include tolylene diisocyanate, diphenylmethane diincyanate, polymethylene polyphenyl polyisocyanate, tolylene diisocyanate, naphthalene diisocyanate, Polyisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate and dicyclohexylmethane diisocyanate; dimers or trimers of these compounds; and these polyisocyanate compounds and trimethylol. Mention may be made of adduct compounds with polyhydric alcohols such as propane or pentaerythritol. Furthermore, in the present invention, urethane prepolymers which are reaction products of these polyisocyanate compounds and the above-mentioned polyhydric alcohols can also be used. In addition, blocked isocyanate compounds, which are reaction products of these polyisocyanate compounds and masking agents such as acidic sodium nitrite, aromatic secondary amines, tertiary alcohols, amide compounds, phenolic compounds, and lactams, are also available. can be used.

In the present invention, the amount of the polyisocyanate compound used as the component (b) is usually 0.6 to 1. It is set within a range of 4 equivalents. In particular, in the present invention, the amount of the polyisocyanate compound used is set so that the amount of isocyanate groups is within the range of 0.8 to 1.2 equivalents per 1 equivalent of hydroxyl groups. This makes it easier to obtain a damping material whose properties such as tensile strength at break, tensile elongation at break, tensile modulus, compressive strength, and isot impact strength are within a good range.

The damping material of the present invention usually comprises the above component (a) and (b).
) by mixing the forming components of the vibration damping material to prepare a composition, shaping the composition into a desired shape, and then heating and curing it! ! ! can be built. When preparing this composition, the composition can also be prepared by dispersing or dissolving the components forming the damping material in an organic solvent or the like. As the organic solvent used in this case, a solvent (for example, an ester solvent such as ethyl acetate) that does not have reactivity with the components (a) and (b) can be used. In addition, when forming a composition into a certain shape, including when using an organic solvent, it is desirable to remove air and organic solvents contained in the composition under reduced pressure.
By doing so, the residual rate of air bubbles and organic solvent in the damping material is reduced.

In addition, the heating temperature during heating curing can be set appropriately considering the type of polyurethane resin used and the curing temperature, but in the present invention, the heating temperature is 50°C.
It is preferable to set the temperature within the range of ~200°C and the heating time within the range of 1 to 72 hours.

Although it is not necessary to use a plasticizer in the vibration damping material according to the present invention, a plasticizer can be used within a range that does not impair the characteristics of the vibration damping material according to the present invention.

Examples of plasticizers that can be used in the present invention include dioctyl phthalate, aromatic polymerized oils and liquid xylene resins.

Furthermore, in order to improve the mechanical strength of the vibration damping material obtained by curing the composition used for manufacturing the vibration damping material according to the present invention, if necessary, it may be added to the composition. ! A natural or organic filler is added. As the inorganic filler, mica, glass flakes, scaly iron oxide, asbestos, etc. are used, and as the organic filler, synthetic pulp, polyamide fiber, carbon fiber, 4t realester fiber, etc. are used.

The damping material of the present invention basically has the above-mentioned polyurethane resin as a main component, and the damping material manufactured using this polyurethane resin has specific physical properties. It is necessary.

That is, in the damping material of the present invention, the maximum value of the loss coefficient (η) expressed by the above equation (3) is 1.3 or more. If the maximum value of the loss coefficient is lower than this value, the vibration of the vibration source cannot be effectively damped.

Incidentally, the vibration damping material of the present invention has a tensile fracture strength of 0.05 to 3.0k (If/1
II2, especially the tensile strength at break is 0,0
5-2, 0) within the range of k(if/lIn2) 6: Al,
, l: is preferred, and the tensile elongation at break measured by a similar method is within the range of 20 to 300%.

Furthermore, the tensile modulus measured in the same manner was 0.1 to 5.
, within the range of 0 kgf/11n2.

Further, the compressive strength measured according to JIS K6911 is 0.5 kgf/In2 or more, and particularly preferably the compressive strength is 20 k (lf#ua2 or more).

Further, it is preferable that the Izot impact strength measured according to JIS K6911 is 5 kg cn/cl1 or more, and in particular, the strength is such that the test piece does not break in the Izod impact strength test.

The fact that the properties of the damping material are within the above range means that the damping material of the invention has good mechanical strength, damping performance, and formability. In addition, by adjusting the types and blending amounts of the components (a) and (b) described above so that the various properties of the vibration damping material of the present invention fall within the above range, the polyurethane resin constituting the vibration damping material can be used. It is not necessary to substantially incorporate volatile components such as plasticizers, or even if they are incorporated, only a very small amount is sufficient. Therefore, the characteristics of the vibration damping material of the present invention hardly change even when used at high temperatures or under high vacuum.

The damping material according to the present invention uses a polyurethane resin obtained by reacting a specific component (a) with a polyisocyanate compound as a component (b), and uses this resin as a main component. Because the vibration damping material has specific physical properties, it has very good properties such as vibration damping performance, mechanical properties, durability, and moldability. Furthermore, by using such a polyurethane resin, there is virtually no need to use a plasticizer, so there is little volatile content even when used at high temperatures or under high vacuum. Its properties are extremely stable, and excellent vibration damping performance can be maintained for a long period of time, even when used under high temperature or high vacuum conditions.

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

100g of polypropylene glycol with an average molecular weight of 400
A 75% by weight ethyl acetate solution of a trimethylolgloban adduct compound of xylylene diisocyanate as a curing agent (incyanate group content: 11.5% by weight) 5
After adding 8.4 g and thoroughly mixing at room temperature, ethyl acetate was distilled off under reduced pressure to defoam. Then, curing temperature: 12
The damping material of the present invention was manufactured by allowing the curing reaction to proceed under the curing conditions of 0° C. and curing time of 3 hours.

For the obtained damping material, the loss coefficient (η), volatile content, tensile strength at break, tensile elongation at break, tensile modulus, compressive strength, isot impact strength, and chipping resistance during bending were determined. It was measured as follows.

The measurement method is as follows.

(Measurement conditions for the loss coefficient (η) of the damping material itself) Equipment: High-frequency viscoelastic spectrometer manufactured by Jikkisui Seisakusho Measurement temperature: 50 to 200°C; sample shape: 2 r
am x thickness 1nm x length 5zw +++ measurement frequency: 40
0H2 Measuring method and principle: When fixing one end of a sample and applying vibration in the longitudinal direction of the sample to the other end, if the sample shrinks, it will sag and measurement cannot be performed.

First, a certain amount of elongation is applied to the sample, and measurements are performed while applying vibrational strain around the elongated point.

This initially applied elongation is called the initial strain (F), and the tension generated when the initial strain is applied is called the initial tension (F).

Vibration distortion (Dynamic d: 5g1
If the amplitude (ΔE) of the aceraent becomes large, the sample will sag, making it impossible to measure -p. This must be taken into account when making measurements.

oynan;c displacement:ΔL
(cz), the vibration force (Dynan
icforce): ΔFo-p(dyne), length of the sample before applying initial strain (natural length L((!11)), cross-sectional area of the sample: A(cj), dynamic dis
The complex modulus of elasticity (Young's modulus) 2E''' (dyne/aa
) is calculated using the following formula.

If E4-(ΔFo-p/ΔLo-p)・([/^), then the dynamic storage modulus E' = E" cosδ (dy
ne/aa) Dynamic loss modulus E”=E” sin δ
(dyne/aa) dynamic viscosity η' −B”
/ω (poise) loss tangent tan
δ=B"/E' = ηω = 2πf f = Frequency (H2) As mentioned above, the initial strain and initial tension are not related to the calculation. The relationship between E', E", E", and δ is shown in Figure 1. It becomes as shown in .

The maximum value of the loss coefficient obtained is η η and laX
The temperature ゝl1aX (T77) is denoted by ax.

(Method for measuring volatile content) According to ASTM E595-77, 125°C x l
Q 'torrx TML (Total
MassLoss ) and CVCM (Collec
ted Volatile Con-densable
Materials) were determined.

(Measurement method of tensile breaking strength, tensile breaking elongation, and tensile modulus) Based on JIS K7113, using a No. 2 test piece,
The temperature was 25±0.2°C and the tensile speed was 10 mm/1 ain.

(Measurement method of compressive strength) Based on JIS K6911 5.19.1, temperature 2
The compression was carried out at 5±0.2°C and at a compression rate of 1 batch/group.

(Method of measuring Izot impact strength) Based on JIS K6911 5.21, temperature 25±
The temperature was 0.2°C.

(Measurement method for chipping resistance during bending) A 1/2 x 1/2 x 5 inch prismatic sample was judged by the presence or absence of cracks in bending until the angles at both ends reached 90 degrees. 6. Those with no cracks were considered to have passed.

The damping performance when the damping material was assembled to a vibrating body as a restraint-type damping material was measured by the following method. i.e. length 300
An aluminum diaphragm with a width of 30++ m and a thickness of 5 cm was attached with a damping material having the same area as the diaphragm and a thickness of 3 cm, and an aluminum restraining plate with the same area as the diaphragm and a thickness of 2 cm. A sample of a restrained vibration damping material having a sandwich structure was prepared, and η of the restrained vibration damping material was measured at a frequency of 400 Hz.

The maximum value of η obtained was set as η3.

The results are shown in Table 1.

Example 1 Example 1 was carried out in the same manner as in Example 1, except that a polyisocyanate compound as shown in Table 1 was used instead of the adduct compound of xylylene diisocyanate.

The results are shown in Table 1.

11 Same as Example 1, except that the polyol resin shown in Table 2 was used instead of the polypromylene glycol with an average molecular weight of 400 used in Example 1, and the amount of polyisocyanate as a curing agent was changed. A damping material was manufactured in the same manner.

The results are shown in Table 2.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship among the loss coefficient δ, dynamic storage modulus E', dynamic loss modulus E', and complex modulus E' of damping material. Agent Patent attorney Shunichi Suzuki Yoshikazu 1 Figure

Claims (1)

[Claims] A damping material containing a polyurethane resin obtained by reacting (a) a polyol resin that is a polyhydric alcohol and/or a polymer thereof, and (b) a polyisocyanate compound, the loss coefficient of the damping material The maximum value of η is 1.3 or more, and the tensile strength at break, tensile elongation at break, and tensile modulus according to JIS K7113 are each 0.05 to 3.
0kgf/mm^2, 20-300% and 0.1-5.
0kgf/mm^2, compressive strength according to JIS K6911 is 0.5kgf/mm^2 or more, and J
Izod impact strength according to ISK6911 is 5kafc
A vibration damping material characterized by having a vibration damping material of m/cm or more.