JP5780492B2 - Silicone composition for vibration damping material and vibration damping material obtained by curing the same - Google Patents

Description

The present invention relates to a silicone composition for damping material that protects various members and devices from vibrations, and a damping material obtained by curing the silicone composition.

Conventionally, these are used for optical signal readers such as compact discs and laser discs (registered trademark), magnetic signal readers such as magnetic discs and magneto-optical discs, precision measuring devices, precision instruments, and pumps that generate vibration. Damping materials made of rubber or elastomer are used to protect against damage caused by vibration. In particular, high-level positioning performance on the order of nm is required for semiconductor manufacturing equipment and the stage of its measuring equipment, and in order to perform high-precision positioning, it is necessary to suppress steady vibration of the equipment and residual vibration during stage operation. Damping material is used.

As damping materials, in addition to damping properties that absorb vibration, high durability that can withstand long-term use, and at the same time, high heat resistance that can withstand the heat generated by absorbing vibration is required. . Up to now, urethane rubber and acrylic rubber have been used as materials with high vibration damping properties, but these have low durability, and their shape changes due to long-term use and numerous vibrations. Are often lost or the material is liquefied (Patent Document 1).
On the other hand, as a silicone-based vibration damping material, a mixture of a viscous liquid such as silicone oil with a solid powder or a silicone gel is known (Patent Documents 2 to 4). Since these are liquids, silicone oil oozes out when used for a long time, easily deforms, and further generates volatile cyclic siloxane, which is impossible for precision instruments and machines that continue to vibrate for a long time. was there.

JP 2004-277604 A JP 2002-69299 A JP-A-5-70693 JP 2002-105316 A

An object of the present invention is to provide a silicone composition for a vibration damping material that provides a vibration damping material having excellent vibration damping properties and durability and heat resistance by being cured.

As a result of intensive studies to solve the above problems, the present inventors can solve the above problems by using a specific trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane and a specific organopolysiloxane (B). As a result, the present invention has been completed.

That is, the present invention relates to the general formula (1):


(Wherein R ¹ represents a methyl group or a phenyl group, and the average repeating unit number m represents an integer of 30 to 1,500) and polysiloxane (1) having silanol groups at both ends It is obtained by subjecting a partial condensate (2) of tetraalkoxysilane represented by the general formula (2): Si (OR ² ) ₄ (wherein R ² represents a methyl group or an ethyl group) to a dealcoholization reaction. Trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A), general formula (3): R ³ ₃ SiX (wherein R ³ is a hydrocarbon group having 1 to 6 carbon atoms, X is a methoxy group, an ethoxy group, or Silane compound (3) represented by the formula (4): SiX ′ ₄ (wherein X ′ represents a methoxy group, an ethoxy group, or a chloro group) (4) ) Hydrolysis, shrinkage The organopolysiloxane (B) and the curing catalyst (C) obtained by combining, the molar ratio of the siloxane units of the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) and the organopolysiloxane (B) ((A ): (B)) is 10: 4-15, and relates to a damping material obtained by curing the silicone composition for damping material.

INDUSTRIAL APPLICABILITY The present invention can provide a vibration damping material that has excellent vibration damping properties, durability that does not deteriorate the vibration damping properties over a long period of use, and heat resistance that hardly causes deterioration due to vibration absorption heat or the like. .

The silicone composition for a damping material of the present invention is characterized by containing a trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A), an organopolysiloxane (B), and a curing catalyst (C).
The trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) of the present invention has the general formula (1):

(Wherein R ¹ represents a methyl group or a phenyl group, and the average repeating unit number m represents an integer of 30 to 1,500) and a polysiloxane having a silanol group at both ends and a general formula ( 2): Obtained by dealcoholizing a partial condensate (2) of tetraalkoxysilane represented by Si (OR ² ) ₄ (wherein R ² represents a methyl group or an ethyl group).

The polysiloxane (1) having silanol groups at both ends used in the present invention has silanol groups at both ends of the main chain represented by the general formula (1), and R ¹ is a methyl group or a phenyl group. This is the base silicone oil.

Examples of the main chain structure of such polysiloxane (1) include polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, and the like, and siloxanes having two or more types of main chain structures may be used in combination. . The polysiloxane (1) used in the present invention does not contain organic covalent bonds (C—C, C—O, Si—C, etc.) in the main chain structure, and has a high heat resistance siloxane bond (Si—O—Si). And a structure in which silanol groups (SiOH) are directly bonded to both ends of the main chain. Common commercially available silicone oils include those containing polyether or polycarbonate in the main chain structure, and organic molecules such as aminopropyl groups, glycidoxypropyl groups, carbitol groups, and (meth) acrylic groups at the molecular ends. Although many have functional groups, the use of these silicone oils containing an organic covalent bond is not preferable because the heat resistance of the cured product is lowered.

The polysiloxane (1) having silanol groups at both ends is generally used from the viewpoint of suitable hardness of the cured product, compatibility with the organopolysiloxane (B) and the viscosity of the resulting silicone composition. The average repeating unit number m in the formula (1) is about 30 to 1,500, preferably 50 to 1,000. The number average molecular weight measured by gel permeation chromatography (GPC, SC8010 manufactured by Tosoh Corp.) of polysiloxane (1) having silanol groups at both ends is about 500 to 100,000, preferably 800 to 70,000. Are preferably used. By setting the number average molecular weight to 500 or more, the hardness of the cured product can be appropriately maintained, and it is preferable because the occurrence of cracks and the like can be suppressed. By setting the number average molecular weight to 100,000 or less, it becomes easy to mix with the organopolysiloxane (B). It is preferable because the viscosity of the resulting silicone composition can be maintained moderately and handling becomes easy.

The tetraalkoxysilane partial condensate (2) is obtained by partially hydrolyzing and condensing the tetraalkoxysilane represented by the general formula (2). Here, R ² represents a methyl group or an ethyl group. When using R ² having a substituent other than a methyl group or an ethyl group, curing of the silicone composition becomes difficult. On the other hand, when R ² is a silanol group, the viscosity stability of the silicone composition is deteriorated and the handling becomes difficult.

Specific examples of such tetraalkoxysilane include tetramethoxysilane and tetraethoxysilane. Among these, it is most preferable to use tetraethoxysilane in which R ² is an ethyl group from the viewpoint of viscosity stability of the silicone composition and ease of curing. On the other hand, instead of tetraalkoxysilane, trialkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, or dimethyldimethoxysilane, dimethyldiethoxysilane, Use of dialkoxysilanes such as diethyldimethoxysilane and diethyldiethoxysilane is not preferable because the heat resistance deteriorates.

The tetraalkoxysilane partial condensate (2) is obtained by subjecting 1 equivalent of the tetraalkoxysilane alkoxy group to a hydrolysis reaction in the range of about 0.125 to 0.33 equivalent, followed by condensation.

Further, the tetraalkoxysilane partial condensate (2) preferably contains 3 to 6 silicon atoms on average per molecule. When the average number of silicon atoms per molecule is less than 3, the proportion of tetraalkoxysilane distilled off from the system while remaining unreacted during the dealcoholization reaction is increased, and the heat resistance of the cured product is lowered. If the average number of silicon atoms per molecule exceeds 6, compatibility with polysiloxane (1) is difficult to obtain, and trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) tends to be difficult to produce. .

The trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) is produced by dealcoholizing the polysiloxane (1) having silanol groups at both ends and the partial condensate (2) of the tetraalkoxysilane. . The ratio of the polysiloxane (1) having silanol groups at both ends and the partial condensate (2) of tetraalkoxysilane is not particularly limited, but the number of moles of the partial condensate (2) of tetraalkoxysilane / The number of moles (molar ratio) of the polysiloxane (1) having a silanol group is preferably 1.5 to 2.5, more preferably 1.6 to 2.0. If it is less than 1.5, gelation tends to occur during the dealcoholization reaction, and if it exceeds 2.5, unreacted alkoxysilane partial condensate (2) that does not react with polysiloxane (1) increases.

Specifically, the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) is, for example, the above-described partial condensate (2) of the polysiloxane (1) having silanol groups at both ends and the tetraalkoxysilane. The transesterification reaction is carried out while distilling off the alcohol produced by charging at a use rate and heating. Although reaction temperature is not specifically limited, Usually, it is about 90-170 degreeC, Preferably it is 110-150 degreeC, and total reaction time is about about 1 to 15 hours normally.

In the above dealcoholization reaction, a known transesterification catalyst can be used to promote the reaction. Examples of the catalyst include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, strontium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium, boron, cadmium, manganese. And metals such as bismuth, oxides thereof, organic acid salts, halides, and alkoxides. Among these, organic tin and organic acid tin are particularly preferable, and specifically, dioctyltin dilaurate and tin octylate are preferable.

In the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) used in the present invention, it is preferable that at least 80% of the terminal silanol groups of the polysiloxane (1) used are modified with alkoxysilane. When the reaction rate is less than 80%, the unreacted alkoxysilane partial condensate (2) increases, and there is a tendency to cause cracks due to volatilization during curing. On the other hand, the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) may contain a partial condensate (2) of unreacted tetraalkoxysilane as long as the amount is small. The partial condensate (2) is cured together with the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) when the silicone composition of the present invention is cured.

The trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) is a block copolymer having polyalkoxysilane segments derived from a partial condensate of tetraalkoxysilane (2) on both sides of a segment derived from polysiloxane (1). is there. The alkoxysilyl groups located at both ends form silica (SiO ₂ ) by sol-gel curing. By concentrating the alkoxysilyl group at both ends, the reactivity of the alkoxysilyl group in the molecule or between the molecules is improved, and the unreacted alkoxysilyl group is prevented from remaining in the cured product. In addition, these silicas are linked by a covalent bond by a segment derived from polysiloxane (1). The segment derived from the polysiloxane (1) does not contain a reactive group in the segment, relieves stress generated during curing, suppresses foaming, and gives toughness and flexibility to the cured product.

The organopolysiloxane (B) of the present invention has the general formula (3): R ³ ₃ SiX (wherein R ³ is a hydrocarbon group having 1 to 6 carbon atoms, X is a methoxy group, an ethoxy group or a chloro group. By hydrolyzing and condensing the silane compound represented by formula (4): SiX ′ ₄ (wherein X ′ represents a methoxy group, an ethoxy group, or a chloro group). can get.

Silane compound (3) represented by the general formula (3): R ³ ₃ SiX (wherein R ³ represents a hydrocarbon group having 1 to 6 carbon atoms, X represents a methoxy group, an ethoxy group or a chloro group) And the general formula (4): SiX ′ ₄ (wherein X ′ represents a methoxy group, an ethoxy group or a chloro group), the use ratio of the silane compound (4) is the number of moles of siloxane units, It is preferable that it is more than compound (3) / silane compound (4) = 0.3. Below this range, the compatibility with the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) is deteriorated, it is not uniform, and sufficient vibration damping properties may not be exhibited.

The amount of water required for the hydrolysis reaction is [number of moles of water used for hydrolysis reaction] / [total number of moles of each alkoxy group or chloro group contained in the general formula (3) and the general formula (4)]. The (molar ratio) is preferably 0.4 or more and 10 or less, more preferably 1. By making the molar ratio within this range, the number of alkoxy groups remaining without being hydrolyzed is reduced, and the amount of water to be removed in the condensation reaction (dehydration reaction) is reduced, thereby producing efficiently. Can do.

  The catalyst used for the hydrolysis reaction is not particularly limited, and a known hydrolysis catalyst can be arbitrarily used. Examples of the hydrolysis catalyst include organic acids, inorganic acids, organic bases, and inorganic bases. Examples of organic acids include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid (succinic acid), maleic acid, methylmalonic acid, adipic acid, and sebacic acid , Gallic acid, butyric acid, meritic acid, arachidonic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid, benzenesulfonic acid Monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid and the like. Examples of inorganic acids include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid and the like. Examples of the organic base include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicyclooctane, diazabicyclononane, Examples thereof include diazabicycloundecene, tetramethylammonium hydroxide, 1,8-diazabicyclo [5,4,0] -7-undecene and the like. Examples of the inorganic base include ammonia, sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide and the like.

Although the addition amount of a catalyst is not specifically limited, Usually, it is 0.1-25 weight part with respect to 100 weight part of total amounts of a silane compound (3) and a silane compound (4). The reaction temperature and time can be arbitrarily set depending on the type of the silane compound, but are usually about 0 to 100 ° C, preferably about 20 to 60 ° C and about 1 minute to 2 hours. The hydrolysis reaction can be performed in the presence or absence of a solvent. The type of the solvent is not particularly limited, and one or more arbitrary solvents can be selected and used.

  A conventionally known dehydration condensation catalyst can be arbitrarily used for the condensation reaction. Examples of the dehydration condensation catalyst include those exemplified for the hydrolysis catalyst. The reaction temperature and time can be arbitrarily set, but are usually about 40 to 150 ° C., preferably 60 to 100 ° C. and about 30 minutes to 12 hours.

The organopolysiloxane (B) preferably has a softening temperature of -20 ° C or higher and 80 ° C or lower. When the silicone composition is cured and used as a vibration damping material within this range, vibration damping in a temperature range of −40 ° C. to 100 ° C. is preferable.
Organopolysiloxane (B) is a polystyrene-reduced weight average molecular weight (M) measured by gel permeation chromatography.
w) is preferably 10,000 or less, and more preferably 3,000 or less. When the weight average molecular weight of the organopolysiloxane (B) is 10,000 or less, the compatibility with the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) becomes better, and the vibration damping property is improved. .

The molar ratio of the siloxane units of the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) and the organopolysiloxane (B) is preferably 10: 4-15. If the molar ratio is less than 10: 4, vibration damping may be insufficient. If the ratio exceeds 10:15, it tends to be difficult to produce a so-called thick molded article that is too hard and exceeds 1 mm when cured.

  The curing catalyst (C) used in the silicone composition of the present invention is for curing the alkoxysilane moiety of the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) and the silanol moiety of the organopolysiloxane (B). It is a required ingredient. As the curing catalyst (C), an organometallic catalyst is used because it is excellent in stability of the silicone composition, hardness of the obtained cured product, heat resistance of the obtained cured product, and the like. Examples of the organometallic catalyst include those containing atoms such as zinc, iron, aluminum, titanium, tin, cobalt, and bismuth, and those containing zinc, aluminum, tin, and bismuth atoms are preferable. Specific examples include organic acid zinc compounds, organic acid tin compounds, organic tin compounds, organic aluminum compounds, and organic acid bismuth compounds. More specifically, zinc octylate, zinc benzoate, zinc p-tert-butylbenzoate, zinc laurate, zinc stearate, aluminum chloride, aluminum perchlorate, aluminum phosphate, aluminum triisopropoxide, aluminum Examples include acetylacetonate, aluminum butoxybisethyl acetoacetate, tetrabutyl titanate, tetraisopropyl titanate, tin octylate, cobalt naphthenate, tin naphthenate, dioctyltin dilaurate, dibutyltin dilaurate, bismuth octylate, and preferably octyl. It is acid tin and dibutyltin dilaurate. These may be used individually by 1 type, or may use 2 or more types together.

  The amount of the curing catalyst (C) is usually about 0.1 to 5 parts by weight when the total of trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) and organopolysiloxane (B) is 100 parts by weight. is there. Curing is facilitated by setting it to 0.1 parts by weight or more, and it is preferable to make it 5 parts by weight or less, since the stability of the silicone composition is improved and the heat resistance of the cured product is further improved.

  In addition to the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A), organopolysiloxane (B), and curing catalyst (C) described above, the silicone composition for vibration damping material of the present invention has the function of the present invention. -Other arbitrary components can be mix | blended in the range which does not impair an effect. Other optional components include, for example, inorganic fillers, inorganic phosphors, anti-aging agents, radical inhibitors, ultraviolet absorbers, adhesion improvers, flame retardants, surfactants, storage stability improvers, ozone deterioration inhibitors, Light stabilizer, Thickener, Plasticizer, Coupling agent, Antioxidant, Thermal stabilizer, Conductivity imparting agent, Antistatic agent, Radiation shielding agent, Nucleating agent, Phosphorus peroxide decomposition agent, Lubricant, Pigment , Metal deactivators, physical property modifiers, organic solvents and the like. These optional components may be used alone or in combination of two or more.

  By mix | blending an inorganic filler, the refractive index of the hardened | cured material obtained and the fluidity | liquidity of a composition can become an appropriate range, or the intensity | strength of hardened | cured material can improve this composition. The inorganic filler is not particularly limited, but is preferably in the form of fine particles that do not deteriorate other properties, such as alumina, aluminum hydroxide, fused silica, crystalline silica, ultrafine amorphous silica, hydrophobic ultrafine silica, Examples include talc, calcium carbonate, barium sulfate, and graphite.

  The silicone composition for vibration damping material of the present invention is known from the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A), organopolysiloxane (B), curing catalyst (C) and optionally contained optional components. It can be prepared by mixing according to the method. Specifically, for example, a trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A), an organopolysiloxane (B), a curing catalyst (C), and the above optional components are usually mixed with a commercially available stirrer (for example, THINKY CONDITIONING The composition of the present invention can be prepared by mixing in MIXER (manufactured by Shinky Co., Ltd., etc.) and mixing uniformly for about 1 to 5 minutes.

  Moreover, although the hardening method at the time of hardening the said silicone composition for damping materials can be performed for about 1 to 12 hours at 80-200 degreeC, for example, by carrying out step cure in the range of 80-200 degreeC. Preferably it is done. For example, step cure can be performed through two or more stages, preferably through the following three stages. First, the composition of the present invention is usually cured at a low temperature of about 80 to 120 ° C. Although hardening time is not specifically limited, Usually, the range of about 0.5 to 2 hours may be sufficient. Next, the low-temperature cured product is usually heat-cured at about 125 to 175 ° C. Although hardening time is not specifically limited, Usually, the range of about 0.5 to 2 hours may be sufficient. Finally, the cured product is heated and cured at about 180 to 200 ° C. Although hardening time is not specifically limited, Usually, the range of about 1 to 10 hours may be sufficient. More specifically, it is preferable that the composition is low-temperature cured at 80 ° C. for 1 hour, then heat-cured at 150 ° C. for 1 hour, and further heat-cured at 200 ° C. for 8 hours. By the step cure through these stages, the resulting composition is excellent in curability and the generation of bubbles is in an appropriate range. Furthermore, it is particularly suitable because a cured product having a thickness of 1 mm or more can be obtained by step cure.

The vibration damping material obtained by curing the silicone composition for vibration damping material of the present invention has a siloxane bond (Si—O—Si) having a main chain structure derived from polysiloxane (1) and an alkoxysilane moiety as a crosslinking site. It has a silica (SiO ₂ ) structure derived from the condensate (2) and the organopolysiloxane (B) and does not contain an organic covalent bond, so it is difficult to thermally decompose, particularly under conditions where heat resistance is required at high temperatures. It is useful as a damping material to be used.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In each example, “parts” and “%” are based on weight unless otherwise specified.

Synthesis Example A1 (Production of trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A))
Polysiloxane (1) of both-end silanol (made by Momentive Performance Materials Japan Co., Ltd., trade name “YF3800”, number average molecular weight, with a reactor equipped with a stirrer, cooling tube, thermometer, and nitrogen introduction tube 6000, in general formula (1), R ¹ is methyl group, m = 80 1900 parts and tetraethoxysilane partial condensate (2) (in general formula (2), R ² is ethyl group, n = 5 1) 471.83 parts were charged and heated. When the temperature reached 140 ° C., 0.48 part of dibutyltin dilaurate was added as a catalyst, and the mixture was reacted at 140 ° C. for 6 hours to obtain a trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A1). In addition, (number of moles of alkoxysilane partial condensate (2) / number of moles of polysiloxane (1) (molar ratio)) at the time of preparation = 2.0. It was confirmed that the amount of ethanol distilled off from the mass difference before and after the reaction was 32.2 parts.

Synthesis Example A2 (Production of trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A))
In the same apparatus as in Synthesis Example 1, polysiloxane (1) of both-end silanols (manufactured by Bluestar Silicones, trade name “48V3500”, number average molecular weight 35,000, in general formula (1), R ¹ is a methyl group, m = 470) and 19.9 parts of tetramethoxysilane partial condensate (2) (in the general formula (2), R ² is a methyl group, n = 5) were charged and heated. When the temperature reached 130 ° C., 0.03 part of dibutyltin dilaurate was added as a catalyst and reacted at 130 ° C. for 6 hours to obtain a trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A2). In addition, (number of moles of alkoxysilane partial condensate (2) / number of moles of polysiloxane (1) (molar ratio)) at the time of preparation = 1.5. It was confirmed that the amount of methanol distilled off from the mass difference before and after the reaction was 2.5 parts.

[Example 1] (Manufacture of silicone composition for vibration damping and sheet-shaped vibration damping material)
Trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A1) 65.8 parts obtained in Synthesis Example A1 and organopolysiloxane (B) trade name “10350tt” (manufactured by Bluestar Silicones, softening temperature 30 ° C., solid content 65 %) Was mixed with 61.5 parts, and 1.0 part of tin octylate as a curing catalyst was mixed to obtain a silicone composition. This silicone composition was poured into a Teflon (registered trademark) cup so that the thickness after curing was 3 mm, and it was cured by heating at 80 ° C. for 1 hour, 150 ° C. for 1 hour, and 200 ° C. for 1 hour. A damping material was obtained.

[Example 2] (Production of silicone rubber composition and silicone rubber sheet)
60.7 parts of trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A2) obtained in Synthesis Example A2, 76.9 parts of organopolysiloxane (B) used in Example 1, and dioctyltin dilaurate as a curing catalyst Was mixed to give a silicone composition. This silicone composition was poured into a Teflon (registered trademark) cup so that the thickness after curing was 3 mm, and it was cured by heating at 80 ° C. for 1 hour, 150 ° C. for 1 hour, and 200 ° C. for 1 hour. A damping material was obtained.

[Example 3] (Manufacture of silicone composition for vibration damping and sheet-shaped damping material)
50.6 parts of trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A2) obtained in Synthesis Example A2, 76.9 parts of organopolysiloxane (B) used in Example 1, and dioctyltin dilaurate as a curing catalyst Was mixed to give a silicone rubber composition. This silicone composition was poured into a Teflon (registered trademark) cup so that the thickness after curing was 3 mm, and it was cured by heating at 80 ° C. for 1 hour, 150 ° C. for 1 hour, and 200 ° C. for 1 hour. A damping material was obtained.

[Comparative Example 1]
An ether-based urethane elastomer product name “Sorbocein 022M” (manufactured by Sanshin Kosan Co., Ltd.) having a thickness of 3 mm was used as a sheet-like vibration damping material.

[Comparative Example 2]
100 parts of trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A2) obtained in Synthesis Example A2 and 1.0 part of dioctyltin dilaurate as a curing catalyst were mixed to obtain a silicone composition. This silicone composition was poured into a Teflon (registered trademark) cup so that the thickness after curing was 3 mm, and it was cured by heating at 80 ° C. for 1 hour, 150 ° C. for 1 hour, and 200 ° C. for 1 hour. A damping material was obtained.

[Comparative Example 3]
100 parts of dimethylpolysiloxane raw rubber with both ends dimethylhydroxysiloxy group blocked (manufactured by Bluestar Silicones, average polymerization degree 1,400), both ends trimethylsiloxy group blocked dimethylsiloxane methyl having 2.4 mol% vinyl group in the side chain 0.8 parts of vinylsiloxane copolymer (manufactured by Bluestar Silicones, average polymerization degree 500), 12 parts of methylphenylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., average polymerization degree 80), BET specific surface area of 200 m @ 2 / g 42.5 parts of fumed silica (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.) and 10 parts of diatomaceous earth (Radiolite F manufactured by Showa Chemical Industry Co., Ltd.) are put into a kneader mixer and kneaded at 100 ° C. A silicone rubber base compound was manufactured.

To 100 parts of this compound, 0.15 part of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as a curing agent is added and mixed uniformly on two rolls to obtain a silicone rubber composition. Manufactured. The silicone rubber composition was compressed at 170 ° C. for 10 minutes to obtain a silicone rubber sheet damping material having a thickness of 3 mm.

The performance of the sheet-shaped damping material obtained as described above was evaluated by the following method.
(Storage modulus, loss tangent)
Each of the sheet-like vibration damping materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was cut into 10 mm × 30 mm to obtain samples, and viscoelasticity measuring instruments (trade name “DMS6100” manufactured by Seiko Instruments Inc.). , Measurement conditions: frequency 10 Hz, slope 3 ° C./min, measurement temperature 0 ° C. to 150 ° C.) were measured for storage elastic modulus and loss elastic modulus, and loss tangent was calculated. The storage elastic modulus at 25 ° C. and 100 ° C. was evaluated as the mechanical strength, and the loss tangent at 25 ° C. and 100 ° C. was evaluated as the vibration damping property.
(Outgas)
The sheet-like damping materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were each cut to 30 mm × 30 mm to prepare samples, and when heated at 180 ° C. for 100 hours in a normal air dryer, the amount of outgas was measured by the following formula. did.
Outgas (%) = (initial weight−weight after 100 hours at 180 ° C.) / (Initial weight) × 100
(Appearance after many vibrations)
The sheet-like vibration damping materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were each cut into 50 mm × 50 mm to obtain samples. The sample was sandwiched between metal plates, pressurized and compressed so as to compress 0.3 mm, and repeated 10 million times at a rate of 10 times per second. After moving up and down a predetermined number of times, it was confirmed whether the sample was broken or not, and whether or not the sample was broken was confirmed. At the same time, it was visually evaluated whether the liquid component oozed out.

Claims (4)

General formula (1):
(Wherein R ¹ represents a methyl group or a phenyl group, and the average repeating unit number m represents an integer of 30 to 1,500) and polysiloxane (1) having silanol groups at both ends It is obtained by subjecting a partial condensate (2) of tetraalkoxysilane represented by the general formula (2): Si (OR ² ) ₄ (wherein R ² represents a methyl group or an ethyl group) to a dealcoholization reaction. Trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A), general formula (3): R ³ ₃ SiX (wherein R ³ is a hydrocarbon group having 1 to 6 carbon atoms, X is a methoxy group, an ethoxy group, or Silane compound (3) represented by the formula (4): SiX ′ ₄ (wherein X ′ represents a methoxy group, an ethoxy group, or a chloro group) (4) ) Hydrolysis, condensation Containing the organopolysiloxane (B) and the curing catalyst (C), the molar ratio of the siloxane units of the trialkoxysilyl group-terminated alkoxysilane-modified polysiloxane (A) and the organopolysiloxane (B) ((A) : (B)) is 10: 4-15, The silicone composition for damping materials characterized by the above-mentioned. The softening temperature of organopolysiloxane (B) is -20 degreeC-80 degreeC, The silicone composition for damping materials of Claim 1 characterized by the above-mentioned. The silicone composition for vibration damping materials according to claim 1 or 2 , wherein the partial condensate (2) of tetraalkoxysilane contains 3 to 6 silicon atoms on an average per molecule. The damping material obtained by hardening the silicone composition for damping materials in any one of Claims 1-3 .