JP2016089057A - Vibration control material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration control material having enhanced heat resistance.SOLUTION: A vibration control material contains a composition containing 100 pts.mass of a copolymer of styrene and a chain hydrocarbon compound having 3 to 6 carbon atoms, 40 pts.mass to 100 pts.mass of a thermoplastic elastomer having difference of an SP vale with the copolymer of 1.0 or more and 5 pts.mass to 50 pts.mass of a hydrogenated petroleum resin as main components and type A hardness defined in JIS K 6253 of a molded article obtained by molding a material containing the composition is 35 or less.SELECTED DRAWING: None

Description

  The present invention relates to a vibration damping material.

  Conventionally, a vibration-damping material is used for a device that is vulnerable to vibration, such as an HDD. As such a vibration damping material, for example, a vibration damping material containing a thermoplastic polymer organic material, a paraffinic process oil, and a hydrogenated petroleum resin is known (see Patent Document 1).

JP 2001-19853 A

  The vibration damping material described in Patent Document 1 exhibits excellent vibration damping properties when used at room temperature. However, for example, when used in an environment where high temperatures (over 60 ° C.) such as the engine room of a car or near a motor are likely to occur, the oil contained in the material deteriorates and oil bleed occurs or heat deterioration (heat dissolution) It sometimes occurred. Therefore, a vibration damping material suitable for use in a high temperature environment has been demanded.

  This invention is completed based on the above situations, Comprising: It aims at providing the damping material which improved heat resistance.

  As a result of intensive studies to solve the above problems, a difference in SP value between the copolymer of styrene and a chain hydrocarbon compound having 3 to 6 carbon atoms and the copolymer is 1.0 or less. It was found that the use of a composition containing a plastic elastomer and a hydrogenated petroleum resin in a predetermined ratio can exhibit a function as a vibration damping material without melting even in a high temperature environment of 60 ° C. or higher.

  That is, according to the present invention, the SP value difference between the copolymer of styrene and a chain hydrocarbon compound having 3 to 6 carbon atoms and the copolymer with respect to 100 parts by mass of the copolymer is 1. A composition containing, as a main component, 40 to 100 parts by mass of a thermoplastic elastomer that is 0 or less, and 5 to 50 parts by mass of a hydrogenated petroleum resin, and molding a material that contains the composition The molded product obtained is a vibration-damping material having a type A hardness of 35 or less as defined in JIS K 6253.

  In the present invention, the vibration damping material includes a copolymer having a styrene and a chain hydrocarbon compound having 3 to 6 carbon atoms and a difference in SP value of 1.0 or less between the copolymer and the copolymer. Since a composition containing a thermoplastic elastomer and a hydrogenated petroleum resin in a predetermined ratio is included, a vibration damping material with improved heat resistance can be provided.

The present invention preferably has the following configuration.
The composition further includes a high heat resistant resin having a heat resistant temperature of 150 ° C. or higher. With such a configuration, the heat resistance can be further improved.

  -The copolymer is a copolymer of styrene and isobutylene. With such a configuration, a product having excellent heat resistance can be obtained.

  -The thermoplastic elastomer is an acrylic thermoplastic elastomer. With such a configuration, a product having excellent heat resistance can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the damping material which improved heat resistance can be provided.

  The damping material of the present invention has a difference in SP value between a copolymer of styrene and a chain hydrocarbon compound having 3 to 6 carbon atoms, and the copolymer with respect to 100 parts by mass of the copolymer. A composition (damping composition) containing 40 parts by mass or more and 100 parts by mass or less of a thermoplastic elastomer that is 1.0 or less and 5 parts by mass or more and 50 parts by mass or less of a hydrogenated petroleum resin is included as a main component.

  As a copolymer of styrene and a chain hydrocarbon compound having 3 to 6 carbon atoms (hereinafter also simply referred to as “copolymer”), one type of chain hydrocarbon compound having 3 to 6 carbon atoms is used. Or what is made by copolymerizing the monomer component containing 2 or more types and styrene is mention | raise | lifted. The monomer component may contain a chain hydrocarbon compound having 2 or less carbon atoms.

  Specific examples of the copolymer include, for example, a styrene-isoprene-styrene block copolymer (SIS), a styrene-isobutylene-styrene block copolymer (SIBS), a styrene-butadiene-styrene block copolymer (SBS), Examples thereof include a styrene-ethylene-propylene block copolymer (SEP), a styrene-ethylene-butylene-styrene block copolymer (SEBS), and a styrene-ethylene-propylene-styrene block copolymer (SEPS). Among these, a copolymer of styrene and a chain hydrocarbon compound having 4 to 5 carbon atoms is preferable, and a styrene-isoprene-styrene block copolymer, a styrene-isobutylene-styrene block copolymer, and a styrene-butadiene- Styrene block copolymers are particularly preferred.

  The copolymer is a thermoplastic polymer. The weight average molecular weight of the copolymer is preferably 200,000 to 400,000. As the copolymer, a polymer obtained by polymerizing monomer components (such as styrene and a chain hydrocarbon having 3 to 6 carbon atoms) constituting the copolymer, a commercially available product, or the like can be used. As a commercially available product, for example, SIBSTAR (registered trademark) 072T manufactured by Kaneka Corporation can be used.

  As the thermoplastic elastomer, those having a difference in SP value from the copolymer of 1.0 or less can be used. When the difference in SP value is 1.0 or less, the compatibility is excellent, and specifically, an acrylic thermoplastic elastomer comprising a block copolymer of a methacrylic ester hard segment and an acrylate ester soft segment, Examples thereof include urethane elastomers and olefin elastomers. As the thermoplastic elastomer, an acrylic thermoplastic elastomer is preferable. As the thermoplastic elastomer, an elastomer obtained by reacting a predetermined monomer may be used, or a commercially available product may be used. As a commercially available product, for example, Clarity (registered trademark) LA2140e manufactured by Kuraray Co., Ltd. can be used.

  Examples of hydrogenated petroleum resins include alicyclic hydrogenated petroleum resins, hydrogenated rosin resins, hydrogenated terpene resins, aromatic petroleum resins, coumarone resins, coal resins, phenol resins, and xylene resins. Among these, a resin having no double bond is preferable, and an alicyclic hydrogenated petroleum resin containing a structural unit represented by the following formula (1) is particularly preferable.

  As the hydrogenated petroleum resin, commercially available products such as Alcon (registered trademark) series (for example, P-140) manufactured by Arakawa Chemical Industries, Ltd. can be used.

  The vibration-damping material contains 40 parts by mass or more and 100 parts by mass or less of a thermoplastic elastomer and 5 parts by mass or more and 50 parts by mass or less of a hydrogenated petroleum resin with respect to 100 parts by mass of the copolymer. A composition is included as a main component.

  When the ratio of the thermoplastic elastomer is less than 40 parts by mass with respect to 100 parts by mass of the copolymer, the hardness is not sufficiently lowered, and when the amount of the thermoplastic elastomer exceeds 100 parts by mass, the damping composition is When a high heat resistant resin is included, it may be difficult to dissolve.

  If the proportion of the hydrogenated petroleum resin is less than 5 parts by mass with respect to 100 parts by mass of the copolymer, there is a risk that sufficient vibration damping properties may not be obtained, and if the proportion of the hydrogenated petroleum resin exceeds 50 parts by mass. Hardness when formed into a molded body is high, and heat resistance is poor.

  The vibration-damping composition preferably contains a high heat-resistant resin having a heat-resistant temperature of 150 ° C. or higher from the viewpoint of reliably improving heat resistance. Examples of the high heat resistance resin include modified polyphenylene ether (PPE / PS-based modified PPE resin), polyphenylene ether / polystyrene alloy (PPS / PS alloy), and syndiotactic polystyrene / polystyrene alloy (SPS / PS alloy). . Of these, modified polyphenylene ether is preferable, and modified polyphenylene ether resin modified with impact-resistant polystyrene (polyphenylene ether content: 60% by mass) is particularly preferable.

  As the high heat resistance resin, for example, commercially available products such as Iupiace (registered trademark) AH60 manufactured by Mitsubishi Engineering Plastics Co., Ltd. can be used. The blending ratio of the high heat resistant resin is preferably 25 parts by mass or less with respect to 100 parts by mass of the copolymer. When a high heat resistant resin is used at such a ratio, the heat resistance is improved while suppressing an increase in hardness.

  In addition to the above vibration damping composition, the vibration damping material includes, for example, a release agent such as calcium stearate, various antioxidants, mica, talc, boron nitride, graphite, sericite, molybdenum disulfide, glass flakes, An additive such as a vibration damping material such as metal flakes and a colorant such as carbon black may be added. The addition amount of the additive is preferably 10 parts by mass or less with respect to 100 parts by mass of the copolymer.

  The vibration damping material of the present invention can be obtained by mixing the material constituting the vibration damping composition and, if necessary, an additive or the like. Examples of the mixing method include a method of mixing the material constituting the vibration damping composition, the additive, and the like with a super mixer or the like.

  Next, the vibration damping material using the vibration damping material of the present invention is a method of forming the vibration damping material into a predetermined shape by granulating the vibration damping material into a pellet shape, and a device for molding the vibration damping material. It can be manufactured by a method such as putting it into a mold and forming it into a predetermined shape. Since the vibration damping material of the present invention is a thermoplastic material, it is suitable for injection molding.

  The damping material obtained by molding the damping material of the present invention preferably has a type A hardness defined by JIS K 6253 of 35 or less. This is because excellent vibration damping properties are exhibited when the type A hardness is 35 or less.

  Since the vibration damping material produced using the vibration damping material of the present invention exhibits vibration damping properties even in a temperature environment of 60 ° C. or higher, the vibration damping material is also used in a high temperature environment such as the engine room of a car or the vicinity of a motor. Useful as a material.

<Example>
Hereinafter, the present invention will be described more specifically with reference to examples.
1. Preparation of damping material (samples a1 to a10 and samples A1 to A3) (1) Preparation of samples a1 to a10 For 100 parts by mass of copolymer A, elastomer, hydrogenated petroleum resin A, modified PPE, stearic acid Ca and Antioxidants were weighed in the proportions (parts by mass) listed in Table 1, and melt-kneaded with a lab plast mill [manufactured by Toyo Seiki Co., Ltd.] to obtain each composition.

Each composition was put into a desktop heating press SA-302 [manufactured by Tester Sangyo Co., Ltd.] to produce a sheet-like molded product having a thickness of 3 mm. A sheet-like sample of 60 mm × 60 mm × 3 mm was cut out from the sheet-like molded product to obtain samples a1 to a10, respectively.
The materials used for preparing samples a1 to a10 are as follows.

Copolymer A: manufactured by Kaneka Corporation, SIBSTAR (registered trademark) 072T
Elastomer: Kuraray Co., Ltd., Clarity (registered trademark) LA2140e, confirmed that the difference in SP value from copolymer A was 1.0 or less Hydrogenated petroleum resin A: Arakawa Chemical Industries, Ltd. Alcon (registered trademark) P-140
Modified PPE: Iupiace (registered trademark) AH60 manufactured by Mitsubishi Engineering Plastics Co., Ltd.
Stearic acid Ca: Dainippon Chemical Co., Ltd., die wax C
Antioxidant: manufactured by BASF Japan, IRGANOX (registered trademark) # 1010
In addition, it confirmed that the difference of SP value of an elastomer and the copolymer A was 1.0 or less.

(2) Preparation of samples A1 to A3 100 parts by mass of copolymer A or SEEPS (styrene-ethylene-ethylene-propylene-styrene copolymer), elastomer, process oil, hydrogenated petroleum resin A, hydrogenated Petroleum resin B, modified PPE, stearic acid Ca, antioxidant, calcium carbonate, lubricant, flow modifier, and colorant were weighed in the proportions (parts by mass) listed in Table 2, and Laboplast Mill [Toyo Seiki ( Each composition was obtained by melt kneading.

Each composition was put into a desktop heating press SA-302 [manufactured by Tester Sangyo Co., Ltd.] to produce a sheet-like molded product having a thickness of 3 mm. A 60 mm × 60 mm × 3 mm sheet-like sample was cut out from the sheet-like molded product to obtain samples A1 to A3, respectively.
The materials used for preparing Samples A1 to A3 are as follows.

Copolymer A: manufactured by Kaneka Corporation, SIBSTAR (registered trademark) 072T
STEPS: Kuraray Co., Ltd., SEPTON (registered trademark) 4055
Elastomer: Kuraray Co., Ltd., Clarity (registered trademark) LA2140e
Process oil: Diana process oil PW-32 manufactured by Idemitsu Kosan Co., Ltd.
Hydrogenated petroleum resin A: Arakawa Chemical Industries, Ltd., Alcon (registered trademark) P-140
Hydrogenated petroleum resin B: Arakawa Chemical Industries, Ltd., Alcon (registered trademark) P-100
Modified PPE: Iupiace (registered trademark) AH60 manufactured by Mitsubishi Engineering Plastics Co., Ltd.
Stearic acid Ca: Dainippon Chemical Co., Ltd., die wax C
Antioxidant: manufactured by BASF Japan, IRGANOX (registered trademark) # 1010
Carbonated Ca: Super S manufactured by Maruo Calcium Co., Ltd.
Lubricant: manufactured by Kao Corporation, Rheodor (registered trademark) SP-S10V
Flow modifier: manufactured by Prime Polymer Co., Ltd., PP (polypropylene) J2021GR
Colorant: Manufactured graphite UFG-30 manufactured by Showa Denko K.K.
In addition, it confirmed that the difference of SP value of an elastomer and the copolymer A was 1.0 or less.

2. Evaluation test (1) Heat resistance test Each sample was placed in a normal temperature oven SH-261 [manufactured by ESPEC CORP.], And when it reached 60 ° C, 85 ° C, and 120 ° C, the state of each sample was visually observed. The temperature was raised to 150 ° C. Subsequently, the sample was heated at 150 ° C. for 2000 hours, and the progress was observed. The heat resistance was evaluated according to the following criteria and shown in Tables 1 and 2. In the case of Δ, ○, and ◎, it was judged that the heat resistance was improved.
X: The shape can be maintained up to 60 ° C.
Δ: The shape can be maintained up to 85 ° C.
A: The shape can be maintained up to 120 ° C.
A: The shape can be maintained up to 150 ° C.

(2) Vibration suppression test
Four test pieces of 5 mm x 5 mm x 3 mm thickness are cut out from each sample, and a load of 1000 g is placed on a vibration table that can be vibrated at an arbitrary frequency under a room temperature condition of 23 ° C. At the four corners, test pieces made of the above materials were sandwiched between the load and the vibration table, and the load was fixed in a state of supporting four points.

  In this state, the vibration table was vibrated at an acceleration of 0.4 G, and the frequency of the vibration was changed from 10 to 1000 Hz over 7.5 minutes to cause primary and secondary resonances. The vibration of the load at this time was detected by an acceleration pickup, and a resonance curve was created based on this data.

Next, based on the resonance frequency f0 (Hz) indicating the peak value (resonance magnification) of the resonance curve and the frequencies f1 and f2 (f1 <f0 <f2) indicating values 3 dB lower than the peak value. The loss coefficient tan δ was calculated from the following mathematical formula (1), and the damping properties were evaluated according to the following criteria, and are shown in Tables 1 and 2. In the case of ◯ and ◎, it was judged that there was vibration control.
×: Loss factor less than 0.5 ○: Loss factor 0.5 or more and less than 1.0 ◎: Loss factor 1.0 or more

  tan δ = Δf / f0 (where Δf = f2−f1) (1)

(3) Hardness Two 60 mm × 60 mm × 3 mm test pieces cut out from each sample were stacked, and according to the method defined in JIS K 6253, the type A hardness was measured 15 seconds after applying a low pressure load. And in Table 2. As a measuring instrument, a constant pressure loader EDL-1 [manufactured by Elastron] was used.

(4) Releasability test After the composition prepared in 1 was put into a mold and molded, it was removed from the mold, and the releasability was judged according to the following criteria and shown in Tables 1 and 2.
×: Difficult to release △: Can be released, but remains adhered ○: Can be released but requires external force ◎: Easy to release

3. Results and Discussion Main composition comprising copolymer A, 40 to 100 parts by mass of thermoplastic elastomer with respect to 100 parts by mass of copolymer A, and 5 to 50 parts by mass of hydrogenated petroleum resin. The sheet produced using the material contained as a component was excellent in vibration damping properties and heat resistance and had a hardness of 35 or less.
In particular, Samples a6, a9 and a10 did not show dissolution even when heated at 150 ° C. for 2000 hours, and were excellent in heat resistance stability.
From these results, it was found that according to the present invention, a vibration damping material with improved heat resistance can be provided.

  Samples a9 and a10 to which stearic acid and an antioxidant were added had excellent heat resistance and vibration damping properties and low hardness, and particularly sample a9 had excellent release properties. From this result, a material containing an antioxidant and Ca stearate is excellent in heat resistance and vibration damping properties, and a vibration damping material having low hardness can be obtained, and it is more preferable if the total amount of addition of the antioxidant and Ca stearate is small. I understood that.

Claims (4)

A copolymer of styrene and a chain hydrocarbon compound having 3 to 6 carbon atoms;
40 mass parts or more and 100 mass parts or less of a thermoplastic elastomer having a difference in SP value of 1.0 or less with respect to 100 mass parts of the copolymer;
A composition containing 5 parts by mass or more and 50 parts by mass or less of hydrogenated petroleum resin as a main component,
A vibration-damping material having a type A hardness defined by JIS K 6253 of a molded product obtained by molding a material containing the composition of 35 or less. The vibration-damping material according to claim 1, wherein the composition further comprises a high heat-resistant resin having a heat-resistant temperature of 150 ° C or higher. The vibration damping material according to claim 1 or 2, wherein the copolymer is a copolymer of styrene and isobutylene. The vibration damping material according to any one of claims 1 to 3, wherein the thermoplastic elastomer is an acrylic thermoplastic elastomer.