JP2000109692A - Vibration-damping silicone composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide vibration-damping silicone compositions with reduced temperature dependence of vibration-damping properties. SOLUTION: Vibration-damping silicone compositions comprise (A) a silicone oil; (B) a silicone oil or a silicone gum which has, at 25 deg.C, a viscosity of not less than 10 times the viscosity of component (A) and, at the same time, is not completely compatible with or soluble in component (A) and increases in the compatibility with or solubility in component (A) with increased temperatures; and (C) a solid powder having an average particle diameter of 0.1-200 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration silicone composition, and more particularly, to an anti-vibration silicone composition having a small temperature dependence of anti-vibration characteristics.

[0002]

2. Description of the Related Art Silicone oil and silica powder,
Vibration-proof silicone compositions comprising solid powders such as glass powders and silicone resin powders are disclosed in, for example, JP-A-63-3
No. 08241 and JP-A-63-308242. However, these vibration-damping silicone compositions have a problem that the vibration-damping properties tend to change with temperature.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have intensively studied the above-mentioned problems, and as a result, have reached the present invention. That is, an object of the present invention is to provide a vibration-proof silicone composition having a small temperature dependency of vibration-proof characteristics.

[0004]

The anti-vibration silicone composition of the present invention has (A) a silicone oil and (B) a viscosity at 25 ° C. that is at least 10 times the viscosity of the component (A). However, the silicone oil or silicone gum which does not completely dissolve or dissolve in the component (A) and becomes more compatible or soluble in the component (A) with increasing temperature, and the (C) average particle size is 0% .1 to 200 .mu.m.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The vibration-proof silicone composition of the present invention will be described in detail. The silicone oil (A) is the main component of the present composition. For example, the viscosity at 25 ° C. is preferably 10,000 mPa · s or less, and particularly preferably in the range of 100 to 5,000 mPa · s. It is preferred that The molecular structure of the component (A) is not limited, and may be, for example, linear, partially branched linear, or branched.
Preferably, it is linear. Examples of the silicone oil of the component (A) include dimethylpolysiloxane in which both ends of the molecular chain are blocked with a trimethylsiloxy group, and a part of the methyl group of the dimethylpolysiloxane is converted to an ethyl group, a propyl group, a butyl group or the like. An aryl group such as a phenyl group, a tolyl group, and a xylyl group; an aralkyl group such as a benzyl group and a phenethyl group; and a diorganopolysiloxane substituted with a halogen atom such as a chlorine atom and a fluorine atom.

On the other hand, at 25 ° C., the component (B)
Having a viscosity of 10 times or more of the viscosity of the component, and
A silicone oil or gum that is not completely compatible or soluble in the component (A) and increases in compatibility or solubility with the component (A) with increasing temperature. It is a component for reducing the property. This is because the viscosity of the component (B) at 25 ° C is (A)
When the viscosity at 25 ° C. of the component is less than 10 times or when the component (B) is completely compatible with or dissolved in the component (A), the obtained vibration-proof silicone composition has poor vibration-proof properties. This is because the temperature easily changes depending on the temperature. In the present composition, the component (B) does not completely dissolve or dissolve in the component (A), and the compatibility or solubility with respect to the component (A) increases with an increase in temperature. Part or all of the components are compatible with or dissolved in the component (A) and become in an equilibrium state, so that the temperature dependence of the vibration damping properties of the composition can be reduced. In particular, since the temperature dependence of the vibration damping properties of the composition becomes smaller, most of the groups bonded to the silicone oil of the component (A) are methyl groups, while the silicone oil or the silicone oil of the component (B) is As a group that binds to the gum, compatibility or solubility is easily controlled, and the resulting vibration-proof silicone composition has excellent heat resistance and can be used in a high temperature range. It is preferred that they are bonded. As such a component (B),
The same silicone oil or silicone gum as exemplified for the component (A) is exemplified, and in fact, the same silicone oil or silicone gum having a different group from the component (A), having the same group as the component (A) has However, silicone oils or gums having different contents are exemplified.

In the present composition, the amount of component (B) is not limited, but the weight ratio of component (A) to component (B) is 50: 5.
The weight ratio is preferably in the range of 0 to 99: 1, and particularly preferably in the range of 70:30 to 95: 5. This is because, if the amount of the component (B) is less than the lower limit of the above range with respect to the weight of the component (A), the temperature dependency of the vibration damping properties of the obtained vibration damping silicone composition tends to increase. On the other hand, if the upper limit of the above range is exceeded, the stability of the obtained vibration damping silicone composition tends to be reduced when it repeatedly undergoes temperature changes.

[0008] The solid powder of the component (C) is a component for imparting a vibration-proof property to the present composition, and has an average particle size in the range of 0.1 to 200 µm, preferably 0 to 200 µm. .1
Within a range of from 100 to 100 μm, particularly preferably from 10 to
It is in the range of 40 μm. Further, the solid powder of the component (C) has a content of solid powder having a particle diameter of 10 μm or less of 1%.
% Or more, and preferably has a particle diameter distribution such that the content of solid powder having a particle diameter of 30 μm or more is 10% by weight or more. Examples of the solid powder of the component (C) include inorganic powders such as silica powder, calcium carbonate powder, and glass powder (beads); organic resin powders such as polyethylene resin powder, acrylic resin powder, and fluororesin powder; silicone resin powder. Is exemplified.

In the present composition, the amount of the component (C) is not limited, but is preferably in the range of 5 to 200 parts by weight based on 100 parts by weight of the total of the components (A) and (B). It is particularly preferred that the amount be in the range of 10 to 150 parts by weight. This is because the compounding amount of the component (C) is different from the component (A) and the component (B).
If the total amount of the components is less than the lower limit of the above range with respect to 100 parts by weight of the total components, the obtained anti-vibration silicone composition tends to have insufficient anti-vibration properties. This is because the obtained anti-vibration silicone composition tends to have insufficient anti-vibration properties.

[0010] The method for producing the vibration-proof silicone composition of the present invention is not limited. For example, a method of mixing the components (A), (B) and (C) with a mixing device, or Component (B) and the component (B) are dissolved in an organic solvent that can be dissolved together, and then the silicone oil composition from which the organic solvent is removed, a method of mixing the component (C), and a method of mixing the component (B)
The latter method is preferable because reaggregation and separation of the components hardly occur.

In the former method, the component (A) and the component (B)
The mixing device for mixing the components and the component (C) is not limited, and examples thereof include well-known mixing devices such as a planetary mixer, a Henschel mixer, and a Hobart mixer.

In the latter production method, examples of the organic solvent capable of dissolving both the component (A) and the component (B) include aromatic organic solvents such as toluene and xylene; acetone and methyl isobutyl ketone. Ketone organic solvents such as
Aliphatic hydrocarbon organic solvents such as hexane, heptane and cyclohexane; and chlorine organic solvents such as chloroform, 1,1,1-trichloroethane and 1,1,1-trichloroethylene.

In the latter method, the amount of the organic solvent is not limited, but is an amount capable of completely dissolving the components (A) and (B). At this time, the components are dissolved by heating. Can be promoted. Thus, (A)
After dissolving the component and the component (B) with an organic solvent, the organic solvent is removed, whereby the component (A) is compatible or not dissolved with the component (A). A silicone oil composition in which the components are uniformly dispersed can be prepared. In particular, even when the obtained anti-vibration silicone composition is repeatedly subjected to a temperature change, the temperature dependency of the anti-vibration characteristics can be suppressed to a small value. Did not dissolve or dissolve
It is preferable to use a silicone oil composition in which the component (B) is dispersed in particles having an average particle diameter of 0.01 to 500 µm.

Next, the component (C) is mixed with the silicone oil composition in which the component (B), which is compatible or insoluble in the component (A), is uniformly dispersed in the component (A). I do. Examples of a method of mixing the component (C) with the silicone oil composition include a method of mixing with the mixing device exemplified above.

The vibration-damping silicone composition of the present invention is suitable as a vibration-damping material in a severe place where it is subjected to a temperature change because its temperature-dependent vibration-damping properties are small.

[0016]

Examples The vibration damping silicone composition of the present invention will be described in more detail with reference to examples. In addition, the viscosity in an Example is a value measured at 25 degreeC. In addition, in order to confirm a change in compatibility or solubility of the component (B) with the component (A) due to an increase in temperature, the light transmittance of the silicone oil composition composed of the components (A) and (B) was measured. Photometer (UV-265FW manufactured by Shimadzu Corporation; wavelength 500 nm; optical path width 1 m)
m). Further, it is dispersed in the component (A).
The average particle diameter (number average particle diameter) of the component (B) was determined by an image processing device connected to an optical microscope. Further, the anti-vibration properties of the anti-vibration silicone composition are determined by RHEOMETRICS
Rheometric Dynamic Analyzer R
Measured by DA-700 (plate method) and its loss factor
(tan δ). The measurement conditions are as follows. Plate diameter: 20mm Frequency: 10Hz Strain: 20% Sample thickness: 1mm

Example 1 200 g of toluene and JISK 6 were placed in a 500 ml three-necked flask equipped with a stirrer.
To 249, 20 g of a dimethylsiloxane / methylphenylsiloxane copolymer (weight ratio of dimethylsiloxane units to methylphenylsiloxane units = 92: 8) having a silanol group at both ends of the molecular chain having a specified plasticity of 100 was added, and stirred. To completely dissolve the copolymer. Next, into this flask, 180 g of a dimethylpolysiloxane having a molecular chain at both ends of trimethylsiloxy group having a viscosity of 1,000 mPa · s was charged, and after stirring uniformly, the mixture was heated to 150 ° C. while reducing pressure to remove toluene. Then, it was cooled to room temperature. The resulting silicone oil composition is
The viscosity was 3,560 mPa · s, and it was a translucent suspension viscous liquid. The above dimethylsiloxane dispersed in a granular form
Average particle size of methylphenylsiloxane copolymer is 2μ
m.

The temperature-viscosity characteristics of this silicone oil composition were measured using a Brookfields rotational viscometer. The results are shown in Table 1. Further, a change in compatibility or solubility between the dimethylsiloxane / methylphenylsiloxane copolymer and dimethylpolysiloxane when the silicone oil composition was heated was observed by a change in light transmittance. The change in the light transmittance is shown in Table 2.

In a Hobart mixer manufactured by Hobart, 100 g of the above-mentioned silicone oil composition and an average particle diameter of 20 μm were added.
m, 162 g of calcium carbonate and an average particle size of 90 μm
m of glass beads, and stirred at low speed.
The mixture was kneaded for 1 hour while being scraped off every minute to prepare a vibration-proof silicone composition. The respective ta at -20 ° C, 25 ° C, and 60 ° C of the vibration-proof silicone composition
Measure nδ, −20 ° C. to tan δ at 25 ° C.,
And the ratio of the respective tan δ at 60 ° C. was determined, and the results are shown in Table 3.

[Embodiment 2] In Embodiment 1, JIS
The amount of the dimethylsiloxane-methylphenylsiloxane copolymer having silanol groups at both ends of the molecular chain having a plasticity of 100 specified in K 6249 is 30 g, and the trimethylsiloxy group at both ends of the molecular chain having a viscosity of 1,000 mPa · s is used. A silicone oil composition was prepared in the same manner as in Example 1, except that the amount of the blocked dimethylpolysiloxane was changed to 170 g. The obtained silicone oil composition had a viscosity of 5,720 mPa · s, and was a translucent suspension viscous liquid. The average particle diameter of the dimethylsiloxane / methylphenylsiloxane copolymer dispersed in a granular form is 2
μm.

The temperature-viscosity characteristics of this silicone oil composition were measured using a rotational viscometer manufactured by Brookfields, and the results are shown in Table 1. Further, a change in compatibility or solubility between the dimethylsiloxane / methylphenylsiloxane copolymer and dimethylpolysiloxane when the silicone oil composition was heated was observed by a change in light transmittance. The change in the light transmittance is shown in Table 2.

In a Hobart mixer manufactured by Hobart, 100 g of the above-mentioned silicone oil composition and an average particle diameter of 20 μm were added.
m, 162 g of calcium carbonate and an average particle size of 90 μm
36 g of glass beads, and stirred at low speed.
The mixture was kneaded for 1 hour while being scraped off every minute to prepare a vibration-proof silicone composition. The respective tan δ at −20 ° C., 25 ° C., and 60 ° C. of the vibration-proof silicone composition were measured, and -20 ° C. and 6
The ratio of each tan δ at 0 ° C. was determined, and the results are shown in Table 3.

Example 3 200 g of toluene and JISK 6 were placed in a 500 ml-three-necked flask equipped with a stirrer.
To 249, 10 g of dimethylpolysiloxane endblocked by trimethylsiloxy groups at both ends of the molecular chain having a specified plasticity of 160 was added, and heated under stirring to completely dissolve it. Next, 190 g of a dimethylsiloxane-methylphenylsiloxane copolymer (molar ratio of methyl groups to phenyl groups = 5: 95) having a molecular chain at both ends of a trimethylsiloxy group and a viscosity of 500 mPa · s was charged into the flask, and the mixture was uniformly mixed. After stirring, the mixture was heated to 150 ° C. under reduced pressure to remove toluene, and then cooled to room temperature. The obtained silicone oil composition had a viscosity of 850 mPa · s and was a translucent suspension viscous liquid. The average particle diameter of the dimethylsiloxane / methylphenylsiloxane copolymer dispersed in a granular form was 30 μm.

The temperature-viscosity characteristics of this silicone oil composition were measured using a rotational viscometer manufactured by Brookfields, and the results are shown in Table 1. Further, a change in compatibility or solubility between the dimethylsiloxane / methylphenylsiloxane copolymer and dimethylpolysiloxane when the silicone oil composition was heated was observed by a change in light transmittance. The change in the light transmittance is shown in Table 2.

In a Hobart mixer manufactured by Hobart Company, 100 g of the above silicone oil composition and an average particle diameter of 20 μm were added.
m, 162 g of calcium carbonate and an average particle size of 90 μm
m of glass beads, and stirred at low speed.
The mixture was kneaded for 1 hour while being scraped off every 0 minutes to prepare a vibration-proof silicone composition. Each of the anti-vibration silicone composition at -20 ° C, 25 ° C, and 60 ° C
The tan δ was measured and -20 to tan δ at 25 ° C.
The ratios of tan δ at 60 ° C. and 60 ° C. were determined and are shown in Table 3.

Example 4 A Hobart mixer manufactured by Hobart Co., Ltd. has a plasticity of 100 specified in JIS K 6249.
A dimethylsiloxane / methylphenylsiloxane copolymer having silanol groups at both ends of a molecular chain (weight ratio of dimethylsiloxane units to methylphenylsiloxane units =
92: 8) 8 g, dimethylpolysiloxane 92 having a viscosity of 1,000 mPa · s and capped with trimethylsiloxy groups at both molecular chain terminals.
g, calcium carbonate having an average particle diameter of 20 μm, and 162 g of glass beads having an average particle diameter of 90 μm were charged, stirred at a low speed, and kneaded for 1 hour while scraping off every 30 minutes to prepare a vibration-proof silicone composition. . The respective tan δ at −20 ° C., 25 ° C., and 60 ° C. of the vibration-proof silicone composition were measured, and the respective tan δ at −20 ° C. and at 60 ° C. with respect to tan δ at 25 ° C.
And the results are shown in Table 3.

[Comparative Examples 1 to 3] Dimethylpolysiloxane having a viscosity of 5,000 mPa · s and capped at both ends of a molecular chain with trimethylsiloxy group, a dimethylpolysiloxane having a viscosity of 12,500 mPa · s and capped at both ends of a molecular chain with trimethylsiloxy group, and The temperature-viscosity characteristics of a dimethylsiloxane-methylphenylsiloxane copolymer (molar ratio of methyl group to phenyl group = 5: 95) having a trimethylsiloxy group at both ends of a molecular chain of 500 mPa · s were measured by Brookfield's rotation method. The results were measured by a viscometer and the results are shown in Table 1.

100 g of these silicone oils, 162 g of calcium carbonate having an average particle diameter of 20 μm, and 36 g of glass beads having an average particle diameter of 90 μm were put into a Hobart mixer manufactured by Hobart, and the mixture was stirred at a low speed and scraped off every 30 minutes. While stirring for one hour, three kinds of vibration-proof silicone compositions were prepared. The tan δ of each of these vibration damping silicone compositions was measured at −20 ° C., 25 ° C., and 60 ° C., and −
The ratio of tan δ at 20 ° C. and 60 ° C. was determined and is shown in Table 3.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

As described above, the vibration damping silicone composition of the present invention is characterized in that the temperature dependency of the vibration damping properties is small.

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Claims (6)

[Claims] 1. A silicone oil (A), (B) at 25 ° C. a viscosity which is at least 10 times the viscosity of the component (A), and which is completely compatible or soluble in the component (A). A silicone oil or silicone gum having increased compatibility or solubility with the component (A) with increasing temperature, and (C) a vibration-proof silicone composition comprising a solid powder having an average particle size of 0.1 to 200 μm. object. 2. Component (A) has a viscosity of 1 at 25 ° C.
A silicone oil of less than 000 mPa · s,
The component (B) has a viscosity at 25 ° C. that is at least 10 times the viscosity of the component (A), and is not completely compatible or dissolved with the component (A). 2. The vibration-damping silicone composition according to claim 1, which is a silicone gum having increased compatibility or solubility with the component (A). 3. The anti-vibration silicone composition comprises the component (A)
After dissolving the component (B) and an organic solvent that can be dissolved together, the silicone oil composition from which the organic solvent has been removed,
(C) a mixture of components,
The vibration damping silicone composition according to claim 1. 4. A silicone oil composition obtained by dissolving the component (A) and the component (B) in an organic solvent which can be dissolved together, and removing the organic solvent at 25 ° C. The component (A) is not compatible or soluble in the component (A).
4. The vibration-proof silicone composition according to claim 3, wherein the component (B) is dispersed in particles having an average particle diameter of 0.01 to 500 [mu] m. 5. The weight ratio of component (A) to component (B) is 50: 5.
The ratio is 0 to 99: 1.
The vibration-proof silicone composition according to any one of the above. 6. The composition according to claim 1, wherein the amount of the component (C) is 5 to 200 parts by weight based on 100 parts by weight of the total of the components (A) and (B). The vibration-proof silicone composition according to any one of the above.