JP2006206885A - Vibration-damping silicone composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration-damping silicone composition capable of maintaining good handling operability even if the value of G* (complex modulus) is heightened according to need. <P>SOLUTION: The vibration-damping silicone compound is obtained by uniformly mixing the below-given components at a temperature of 70°C or higher: (A) 100 parts by weight of a silicone oil; (B) 10 to 300 parts by weight of a silicone resin powder that contains 0.1 to 10 wt.% of silicon-bonded hydroxy groups and/or alkoxy groups; and (C) 0.5 to 50 parts by weight of an organosiloxane oligomer represented by the following average unit formula: R<SP>1</SP><SB>a</SB>X<SB>b</SB>SiO<SB>(4-a-b)/2</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an anti-vibration silicone compound, and more particularly to an anti-vibration silicone compound that exhibits excellent fluidity even when G ^* correlated with a resonance frequency is increased.

Many anti-vibration compounds composed of viscous liquid and solid powder have been proposed. For example, an anti-vibration compound (see JP-A-63-308241) composed of a viscous liquid such as silicone oil and a solid powder such as silica powder, glass powder, or silicone resin powder, or a viscous liquid such as silicone oil and a silicone resin powder. An anti-vibration composition (see JP-A-10-251517), a viscous fluid in which silsesquioxane powder and unsurface-treated wet fine powder silica are blended with silicone oil (see JP-A-10-281202), Viscous fluid in which silsesquioxane powder, wet fine powder silica and silanol group-terminated dimethylsiloxane are blended with silicone oil (see JP-A-11-182624), wet powder with silicone resin powder and hydrophobic treatment on the surface Viscous fluid containing silica (JP 2002-16120 A) See JP) it has been proposed.
In general, a material having a high resonance frequency is required for use in a small vibration isolator. This is because if the resonance frequency of the material is low, there is an advantage that the attenuation frequency region is widened, but the amplitude becomes large, and there is a restriction that a large clearance is required. From experience, it is known that the resonance frequency increases when the value of G ^* , which is one of the viscoelastic properties of the material, is high. However, the conventional vibration-proof compound as described above has a problem that when the value of G ^* is increased, the viscosity increases at the same time and the handling workability may be deteriorated.

JP-A-63-308241 JP-A-10-251517 JP-A-10-281202 JP-A-11-182624 JP 2002-161206 A

An object of the present invention is to provide a vibration-proof silicone compound capable of maintaining good fluidity even if G ^* is increased as necessary.

The object is achieved by a vibration-proof silicone compound characterized by uniformly mixing the following components at a temperature of 70 ° C. or higher.
(A) 100 parts by weight of silicone oil,
(B) 10 to 300 parts by weight of a silicone resin powder containing 0.1 to 10% by weight of a silicon atom-bonded hydroxyl group and / or an alkoxy group having 1 to 5 carbon atoms,
And (C) the average unit formula; R ¹ _a X _b SiO _{(4-ab) / 2}
(In the formula, R ¹ is a monovalent hydrocarbon group or halogenated alkyl group having 1 to 10 carbon atoms, X is a hydroxyl group and / or an alkoxy group having 1 to 5 carbon atoms, and a and b are positive numbers. And 0 <a <4, 0 <b <4, 0 <a + b <4)) 0.5 to 50 parts by weight of an organosiloxane oligomer

Anti Fusei silicone compositions of the present invention, since the mixed above (A) ~ (C) component predetermined amounts uniformly at a temperature above 70 ° C., better even by increasing the G ^* necessary flow properties It has the feature that can be maintained.

The component (A) silicone oil is a medium for dispersing the component (B) silicone resin powder, and is a liquid organopolysiloxane at room temperature. In this organopolysiloxane, groups bonded to silicon atoms include alkyl groups such as methyl, ethyl and propyl groups; alkenyl groups such as vinyl, allyl and butenyl groups; aryl groups such as phenyl and tolyl groups. Examples thereof include monovalent hydrocarbon groups having 1 to 10 carbon atoms such as C 1-10 and halogenated alkyl groups having 1 to 10 carbon atoms such as 3,3,3-trifluoropropyl group. These groups may be substituted with a small amount of an alkoxy group such as a hydroxyl group, a methoxy group, or an ethoxy group. Especially, since the temperature dependence of a viscosity change is small, it is desirable that it is an alkyl group, and it is especially preferable that it is a methyl group. In addition, examples of the molecular structure of the silicone oil as the component (A) include linear, branched, and cyclic, but linear is preferable. The kinematic viscosity at 25 ° C. of the silicone oil is preferably in the range of 1000~1,000,000mm ² / s, in particular, more preferably in the range of 5000~500,000mm ² / s, 10, More preferably, it is in the range of 000 to 500,000 mm ² / s. This is because when the kinematic viscosity at 25 ° C. is less than the lower limit of the above range, the dispersibility of the silicone resin powder of the component (B) tends to be deteriorated and tends to be separated. This is because the properties may deteriorate and it may be difficult to disperse the silicone resin powder of component (B).

Especially, since the value of G ^* can be made high when the kinematic viscosity in 25 degreeC of (A) component is the range of 10,000-500,000 mm < ² > / s, it is the most preferable. As described above, it is known from experience that there is a correlation between the value of G ^* and the resonance frequency of the vibration isolator ^{. When} the value of G ^* of the silicone compound of the present invention is high, it is used for a small vibration isolator. This is advantageous because the resonance frequency can be increased. This is because, in general, a small vibration isolator is required to have a material having a high resonance frequency.

  As the silicone oil of component (A), trimethylsiloxy group-capped dimethylpolysiloxane, trimethylsiloxy group-capped methyloctylpolysiloxane, vinyldimethylsiloxy group-capped dimethylpolysiloxane, silanol group-capped dimethylpolysiloxane, trimethylsiloxy group-capped dimethylsiloxane, A methylphenylsiloxane copolymer is exemplified.

The component (B) silicone resin powder is a component for blending with the (A) silicone oil to impart vibration-proof properties to the vibration-proof silicone compound of the present invention and at the same time reduce the temperature dependence of the vibration-proof properties. is there. The main skeleton is a siloxane unit represented by the formula: RSiO _3/2 and / or a siloxane unit represented by the formula: SiO _4/2 . Furthermore, other optional siloxane units include R ₂ SiO _2/2 units and R ₃ SiO _1/2 units. Of these, an organopolysilsesquioxane powder consisting only of RSiO _3/2 units is preferred. R represents an alkyl group such as a methyl group, an ethyl group or a propyl group; an alkenyl group such as a vinyl group, an allyl group or a butenyl group; a monovalent group having 1 to 10 carbon atoms such as an aryl group such as a phenyl group or a tolyl group. Examples thereof include hydrocarbon groups and halogenated alkyl groups having 1 to 10 carbon atoms such as 3,3,3-trifluoropropyl groups. Among these, an alkyl group is preferable, and a methyl group is particularly preferable, and at least 50% or more is more preferably a methyl group. Some of these groups are substituted with a hydroxyl group and / or an alkoxy group having 1 to 5 carbon atoms such as a methoxy group or an ethoxy group, and the amount thereof is 0.1 to 10 weight in the component (B). %. (B) It is preferable that the average particle diameter of a component is the range of 1-100 micrometers, and it is more preferable that it is the range of 10-40 micrometers. Moreover, the shape includes a spherical shape, a flat shape, and an indefinite shape.

  Component (B) is an organopolysiloxane powder that is solid at room temperature and preferably has no melting point. This is because if the component (B) has a melting point, depending on the use conditions of the vibration-proof silicone compound of the present invention, the vibration-proof characteristics may vary depending on the use temperature, which may be undesirable.

(B) The compounding quantity of a component is the range of 10-300 weight part with respect to 100 weight part of said (A) silicone oil normally, Preferably it is the range of 30-200 weight part. This is because the amount of the component (B) is less than 10 parts by weight, the silicone compound of the present invention has insufficient vibration-proofing properties, or the temperature dependency of the vibration-proofing properties tends to be significant. It is because workability will fall when it exceeds 300 weight part.

The component (C) is a surface treatment agent for the silicone resin powder (B) and imparts an effect of lowering the apparent viscosity of the silicone compound of the present invention. The component (C) is a siloxane oligomer represented by an average unit formula: R ¹ _a X _b SiO _{(4-ab) / 2} . In the formula, R ¹ is a monovalent hydrocarbon group having 1 to 10 carbon atoms or a halogenated alkyl group, an alkyl group such as a methyl group, an ethyl group, or a propyl group; and a 3,3,3-trifluoropropyl group. Illustrated. Among them, a methyl group is preferable because the steric hindrance of the component (C) is reduced and the silicone resin powder easily reacts. X is a hydroxyl group or an alkoxy group having 1 to 5 carbon atoms such as a methoxy group or an ethoxy group. (B) A hydroxyl group is preferred because it easily reacts with the silicone resin powder. a and b are positive numbers, 0 <a <4, 0 <b <4, 0 <a + b <4, 1.5 ≦ a ≦ 2, 0 <b <0.5, 1.5 <a + b <2.5 is preferable, and 1.8 ≦ a ≦ 2, 0 <b <0.4, and 1.8 <a + b <2.4 are more preferable.

Examples of the molecular structure of the organosiloxane oligomer include linear, branched, and cyclic structures, and it is particularly preferable that the organosiloxane oligomer has a linear structure. This is because when the molecular structure is linear, it easily reacts with the (B) silicone resin powder. That the kinematic viscosity at 25 ° C. organosiloxane oligomer is in the range of (A) less than the dynamic viscosity of the silicone oil is preferably in the range of 5 to 500 mm ² / s, in particular, 10 to 100 mm ² / s Is more preferable. If the kinematic viscosity at 25 ° C. is less than the lower limit of the above range, it tends to volatilize and workability tends to deteriorate. On the other hand, if the upper limit of the range is exceeded, the reactivity with the silicone resin powder tends to deteriorate. Because there is. The compounding amount of the organosiloxane oligomer is usually in the range of 0.5 to 50 parts by weight, preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the silicone oil. When the compounding amount of the organosiloxane oligomer is less than the lower limit of the above range, the effect of lowering the apparent viscosity of the silicone compound of the present invention is hardly obtained, and when the upper limit of the range is exceeded, depending on the type of the component (C) This is because separation of component (C) may occur.

式中Ｒ^１は上記と同様であり、ｎは（Ａ）シリコーンオイルの重合度より小さく、０〜１００の整数であり、２〜２０の整数であることが好ましい。 Preferred examples of the component (C) include molecular chain both-end silanol-blocked diorganopolysiloxane represented by the following formula.

In the formula, R ¹ is the same as described above, and n is smaller than the polymerization degree of (A) silicone oil, is an integer of 0 to 100, and is preferably an integer of 2 to 20.

The silicone compound of the present invention comprises the above components (A) to (C), but as other optional components, inorganic fine powders such as glass fine powder, silica fine powder, clay, bentonite, diatomaceous earth, and quartz powder; Compounding organic resin fine powder such as acrylic resin fine powder, fluororesin fine powder, phenol resin fine powder, antioxidant, rust inhibitor, flame retardant, pigment, dye, etc. is the purpose of the present invention. There is no problem as long as it is not damaged. In addition, it is preferable that the silicone compound of this invention does not contain the inorganic fine powder, especially the silica fine powder which has many hydroxyl groups on the particle | grain surface. This is because when an inorganic fine powder having a large number of hydroxyl groups on the surface is blended with the silicone compound of the present invention, the thixotropy of the silicone compound is increased, making it difficult to remove bubbles during compound production, or an encapsulant that encapsulates the silicone compound. This is because it may be difficult to fill the container and workability may be reduced. Further, when the thixotropy of the silicone compound is increased by blending silica fine powder or the like, tan δ in the low frequency region is decreased and the vibration isolation characteristics of the silicone compound tend to deteriorate.
The silicone compound of the present invention is preferably a liquid having an apparent viscosity of 0.01 to 10,000 Pa · s at 25 ° C., and more preferably in the range of an apparent viscosity of 0.1 to 4,000 Pa · s. preferable. This is because, if the upper limit of the above range is exceeded, it is difficult to remove bubbles, or filling into the enclosure that encloses the silicone compound becomes difficult, and workability is reduced.

  The method for preparing the silicone compound of the present invention comprises: (A) silicone oil, (B) silicone resin powder, and (C) organosiloxane oligomer, ball mill, vibration mill, kneader mixer, screw extruder, paddle mixer, ribbon mixer. , Banbury mixer, Ross mixer, Henschel mixer, flow jet mixer, Hobart mixer, roll mill, and the like. In mixing, the above (B) silicone resin powder and (C) organosiloxane oligomer are heated to 70 ° C. or higher in order to efficiently react. In order to improve the dispersion of the component (B), the components (A) to (C) may be kneaded until uniform at room temperature and then kneaded at a temperature of 70 ° C. or higher. The heating temperature is preferably 70 to 200 ° C. The mixing pressure may be normal pressure, but it is preferable to mix under reduced pressure.

The anti-vibration silicone compound of the present invention is characterized by exhibiting excellent anti-vibration properties. Therefore, the silicone compound of the present invention can be used as a vibration isolator by enclosing it in a bag-like or cylindrical enclosure made of an elastic material such as thermoplastic elastomer or rubber. In addition, the G ^* value can be increased without impairing handling workability, and since the main component is a silicone-based material, it has the characteristic that the temperature dependence of the vibration isolation characteristics is low. , Compact disc changers, mini disc players, car navigation devices, etc., which require miniaturization of parts and high vibration isolation characteristics, and are used for small vibration isolation devices for electrical and electronic equipment used in environments with large temperature changes. It is suitable as a vibration compound.

The vibration-proof silicone compound of the present invention will be described in detail by way of examples. In the examples, the kinematic viscosity is a value measured at 25 ° C., and the apparent viscosity is a rotor viscometer manufactured by Brookfield Co., Ltd. 14 was measured under the conditions of 25 ° C. and 0.5 rpm. The anti-vibration characteristics were evaluated by measuring the loss tangent coefficient (tan δ) at 25 ° C. and G ^* . Tan δ and G ^* were measured by a plate method using a dynamic analyzer RDA-700 manufactured by Rheometric. The measurement conditions were plate diameter: 25 mm, frequency: 0.1 Hz, 1 Hz, 10 Hz, 40 Hz, strain: 5%, sample thickness: 2 mm.

[Example 1]
490 g of trimethylsiloxy group-blocked dimethylpolysiloxane having a kinematic viscosity of 100,000 mm ² / s in a mixer, methylpolysilsesquioxane powder (average particle diameter) composed of siloxane units represented by the formula: CH ₃ SiO _3/2 480 g and hydroxyl group content 3.7 wt%) 480 g, and 30 g of both ends hydroxy group-blocked dimethylpolysiloxane having a kinematic viscosity of 40 mm ² / s, and mixing them uniformly while scraping them off at a low speed (150 rpm) Further, the mixture was heated to 100 ° C. under reduced pressure (100 mmHg) and kneaded for 2 hours. The anti-vibration properties and viscosity of the obtained silicone composition were measured, and the results are shown in Table 1.

[Example 2]
Both ends trimethyl kinematic viscosity 100,000 mm ² / s to the mixer siloxy group-blocked dimethylpolysiloxane 330 g, kinematic viscosity 300,000mm ² / s terminated at both ends with trimethylsiloxy group dimethylpolysiloxane 220g of the _formula: CH _{3 SiO 3/2} in methyl polysilsesquioxane sesquicarbonate composed of siloxane units represented silsesquioxane powder (average particle size of 20 [mu] m, a hydroxyl group content of 3.7 wt%) 440 g, and both ends of the kinematic viscosity 40 mm ² / s hydroxy groups dimethylpolysiloxane capped 50 g of siloxane was added, and these were uniformly mixed while scraping off at a low speed (150 rpm), and further heated at 100 ° C. under reduced pressure (100 mmHg) and kneaded for 2 hours. The anti-vibration properties and viscosity of the obtained silicone composition were measured, and the results are shown in Table 1.

[Comparative Example 1]
Methyl polysilsesquioxane powder (average particle) composed of 490 g of both ends trimethylsiloxy-blocked dimethylpolysiloxane having a kinematic viscosity of 100,000 mm ² / s and a siloxane unit represented by the formula: CH ₃ SiO _3/2 in a mixer 480 g of a particle having a diameter of 20 μm and a hydroxyl group content of 3.7% by weight was added, and these were uniformly mixed while scraping off at a low speed (150 rpm), and further kneaded for 2 hours. The maximum temperature during that time was 40 ° C. The anti-vibration properties and viscosity of the obtained silicone composition were measured, and the results are shown in Table 1.

[Comparative Example 2]
490 g of trimethylsiloxy group-blocked dimethylpolysiloxane having a kinematic viscosity of 100,000 mm ² / s in a mixer, methylpolysilsesquioxane powder (average particle diameter) composed of siloxane units represented by the formula: CH ₃ SiO _3/2 480 g and hydroxyl group content 3.7 wt%) 480 g, and 30 g of both ends hydroxy group-blocked dimethylpolysiloxane having a kinematic viscosity of 40 mm ² / s, and mixing them uniformly while scraping them off at a low speed (150 rpm) The mixture was further kneaded for 2 hours. The maximum temperature during that time was 40 ° C. The anti-vibration properties and viscosity of the obtained silicone composition were measured, and the results are shown in Table 1.

[Table 1] [Anti-Vibration Properties and Apparent Viscosity of Silicone Compound at 25 ° C]

Claims (8)

An anti-vibration silicone compound characterized by uniformly mixing the following components at a temperature of 70 ° C. or higher;
(A) 100 parts by weight of silicone oil,
(B) 10 to 300 parts by weight of a silicone resin powder containing 0.1 to 10% by weight of a silicon atom-bonded hydroxyl group and / or an alkoxy group having 1 to 5 carbon atoms,
And (C) the average unit formula; R ¹ _a X _b SiO _{(4-ab) / 2}
(In the formula, R ¹ is a monovalent hydrocarbon group or halogenated alkyl group having 1 to 10 carbon atoms, X is a hydroxyl group and / or an alkoxy group having 1 to 5 carbon atoms, and a and b are positive numbers. And 0 <a <4, 0 <b <4, 0 <a + b <4)) 0.5 to 50 parts by weight of an organosiloxane oligomer The kinematic viscosity of the component (A) at 25 ° C. is 1,000 to 1,000,000 mm ² / s, and the vibration-proof silicone compound according to claim 1. The average particle size of the silicone resin powder as the component (B) is 1 to 100 µm, and the vibration-proof silicone compound according to claim 1 or 2. The silicone resin powder as component (B) comprises a siloxane unit represented by RSiO _3/2 (wherein R is a monovalent hydrocarbon group or halogenated alkyl group having 1 to 10 carbon atoms). The vibration-proof silicone compound according to claim 1 or 2. The vibration-proof silicone compound according to claim 1 or 2, wherein the organosiloxane oligomer of component (C) has a kinematic viscosity at 25 ° C of 5 to 500 mm ² / s. The anti-vibration silicone compound according to claim 1 or 2, wherein the organosiloxane oligomer of component (C) is represented by the following average unit formula. ;
R ¹ _a X _b SiO _{(4-ab) / 2}
(In the formula, R ¹ is a monovalent hydrocarbon group or halogenated alkyl group having 1 to 10 carbon atoms, X is a hydroxyl group and / or an alkoxy group having 1 to 5 carbon atoms, and a and b are positive numbers. Yes, 1.8 ≦ a ≦ 2.4, 0 <b <0.4, 1.8 <a + b <2.4. The vibration-proof silicone compound according to claim 1 or 2, wherein the organosiloxane oligomer of component (C) is represented by the following formula. ;

(In the formula, R ¹ is a hydrocarbon group or halogenated alkyl group having 1 to 10 carbon atoms, and n is an integer of 0 to 100.) An anti-vibration device comprising the anti-vibration silicone compound according to claim 1 enclosed in an enclosure made of an elastic material.