JPH07137194A - Vibration-damping metal compound - Google Patents

Abstract

PURPOSE:To ensure that vibration-absorbing properties are improved and bending and drawing requirements are satisfied by using a molding consisting of a composition containing a block copolymer of two polymer blocks with a specific range of number average molecular weight and a metal as constituent elements. CONSTITUTION:A metal compound is obtained from a molding consisting of a composition containing a block copolymer, with a number average molecular weight of 2,000 to 50,000, which is composed of a polymer block A and a polymer block B. The polymer block A is a polymer of a vinyl aromatic monomer with a number average molecular weight of 2,500 to 40,000, while the polymer block B is a polymer consisting of isobutylene with a number average molecular weight of 1,000 to 4,000. The ratio of the polymer A and the polymer B should preferably be 5 to 80wt.% for A and 95 to 20wt.% for B. In addition, the metal used is cold-rolled steel sheet, carbon steel sheet or stainless steel sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping metal composite using a molded product made of a composition containing a block copolymer having excellent vibration damping performance (vibration absorption).

[0002]

2. Description of the Related Art In recent years, the problems of noise and vibration have become a major social problem due to the development of transportation facilities. Also, in the field of precision machinery and electronics, the adverse effect of vibration has become a problem, and materials and molded products that are excellent in vibration damping performance (vibration absorption) and noise prevention are required. Materials having such characteristics include natural rubber,
A vibration-damping composite material (damping steel plate) in which vulcanized rubber such as butyl rubber or styrene-butadiene rubber is attached to a metal plate, or viscoelastic resin such as polyester resin, polyamide resin, or epoxy resin is restrained by the metal plate. Are used in automobile oil pans, engine covers, floors, office automation equipment, household electric appliances, and the like.

[0003]

However, in the case of vulcanized rubber, it takes a lot of time and effort to mix and vulcanize and then to apply, and the above-mentioned viscoelastic resin is poor in flexibility and processed after being formed into a metal composite. There is a problem with sex. Furthermore, with these resins, the film is heated and pressure bonded to the metal plate after molding,
There is also a problem that heat is applied during film formation to cure the resin.

An object of the present invention is to provide a vibration-damping metal composite having excellent vibration-damping performance (vibration absorption) and capable of bending and drawing metals.

[0005]

According to the present invention, the above object is achieved by the number average molecular weight of 20,000 to 5,000 comprising the following polymer block (A) and polymer block (B).
It is achieved by providing a molded article made of a composition containing the block copolymer of No. 00 and a vibration damping metal composite made of a metal. (A) Number average molecular weight of vinyl aromatic monomer 25
Polymer block of 00-400000. (B) Number average molecular weight of isobutylene 10,000 to 10,000
400000 polymer blocks.

The block copolymer used in the present invention is
A block copolymer (hereinafter referred to as "A / B block copolymer") comprising a polymer block (A) made of a vinyl aromatic monomer and a polymer block (B) made of isobutylene, and the polymer block (A) The vinyl aromatic monomer constituting the above may be any vinyl aromatic monomer capable of being cationically polymerized, for example, styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, α.
-Methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-
Benzylstyrene, 4- (phenylbutyl) styrene,
2,4,6-trimethylstyrene, monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, indene, acenaphthylene and the like can be mentioned. These vinyl aromatic monomers can be used alone or in combination of two or more. Most preferably, the polymer block (A) is composed of styrene.

The polymer block (A) must have a number average molecular weight of 2,500 to 400,000, preferably 5,000 to 300,000. When the number average molecular weight of the polymer block (A) is less than 2500, the mechanical properties of the A / B block copolymer are inferior, while when it exceeds 400000, the A / B
The melt viscosity of the block copolymer becomes too high, and the processability decreases.

The polymer block (B) in the A / B block copolymer must be composed of isobutylene and have a number average molecular weight of 10,000 to 400,000. The number average molecular weight of the polymer block (B) is 1000.
When it is less than 0, the flexibility of the A / B block copolymer is lost, while when it exceeds 400000, the fluidity of the A / B block copolymer is lowered and molding and processing become difficult. By using a block composed of isobutylene as one component of the block copolymer, an A / B block copolymer having excellent vibration damping performance (vibration absorption) with a mechanical loss coefficient (tan δ) of 0.1 or more can be obtained. can get.

The number average molecular weight of the A / B block copolymer consisting of the polymer block (A) and the polymer block (B) is required to be 20,000 to 500,000, preferably 30,000 to 400,000. preferable. Number average molecular weight of A / B block copolymer is 20,000
If it is smaller than the above range, mechanical properties such as strength and elongation of the A / B block copolymer are deteriorated. On the other hand, 500000
If it exceeds the range, the fluidity of the A / B block copolymer is lowered, and the moldability and processability are lowered.

The ratio of the polymer block (A) to the polymer block (B) in the A / B block copolymer is A / B.
The ratio of the polymer block (A) is generally based on the weight of the A / B block copolymer, although it depends on the number average molecular weight of the block copolymer, the polymer block (A) and the polymer block (B). Is 5 to 80% by weight, the proportion of the polymer block (B) is preferably 95 to 20% by weight, and the proportion of the polymer block (A) is 10 to 75% by weight.
It is more preferable that the proportion of the polymer block (B) is 90 to 25% by weight. If the proportion of the polymer block (A) is less than 5% by weight [the proportion of the polymer block (B) exceeds 95% by weight], the strength characteristics of the A / B block copolymer will be insufficient. When the proportion of the polymer block (A) exceeds 80% by weight [when the proportion of the polymer block (B) is less than 20% by weight], the melt viscosity becomes high,
Moldability and workability are reduced. In addition, the vibration damping performance (vibration absorption) is also unfavorable.

The A / B block copolymer may be linear or branched in two or more,
Further, the structure is not particularly limited as long as it has at least one polymer block (A) and at least one polymer block (B) in the molecule. Although not limited, typical examples of the A / B block copolymer include those represented by the following formula (I) or formula (II).

Q- [C (R ¹ ) (R ² )-(BA) _m ] _n (I)

Q- [C (R ¹ ) (R ² )-(AB) _m ] _n (II) [In the above formulas (I) and (II), Q is an n-valent hydrocarbon group, A Is a polymer block (A), B is a polymer block (B), R ¹ and R ² are alkyl groups or aralkyl groups having 1 to 20 carbon atoms, m and n are integers of 1 or more,
It is preferred that m is 1. ]

The method for producing the A / B block copolymer is not particularly limited. For example, it can be produced by sequentially polymerizing a vinyl aromatic monomer and isobutylene in an inert solvent using a suitable polymerization initiator system. it can. An example of the polymerization initiator system in that case is a mixed system of a Lewis acid and an organic compound which produces a cationic polymerization active species by the Lewis acid. The Lewis acid is titanium tetrachloride, tin tetrachloride, boron trichloride, aluminum chloride or the like, and the organic compound is an organic compound having a functional group such as an alkoxy group, an acyloxy group or a halogen, for example, bis (2- Methoxy-2-propyl) benzene, bis (2-acetoxy-2-propyl) benzene, bis (2
-Chloro-2-propyl) benzene and the like.
If necessary, amides such as N, N-dimethylacetamide and esters such as ethyl acetate may be used as the third component together with the above-mentioned Lewis acid and organic compound. Further, as an inert solvent for polymerization, hexane, cyclohexane, methylcyclohexane, methyl chloride, methylene chloride and the like can be used.

Linear A / B block copolymers can be obtained, for example, by using (1) a Lewis acid and a compound having one functional group which produces a cationic polymerization active species as a polymerization initiator system, and a vinyl aromatic group. After polymerizing a group monomer to form a polymer block (A), isobutylene is added into the reaction system to polymerize to form a polymer block (B), and a vinyl aromatic monomer is further added if necessary. To polymerize to form polymer block (A), (2) first polymerize isobutylene using a Lewis acid and a compound having two functional groups that generate cationic polymerization active species as a polymerization initiator system. After forming the polymer block (B), a vinyl aromatic monomer is added to the reaction system to carry out polymerization to form the polymer block (A). That.

In the branched A / B block copolymer, for example, a compound having three or more functional groups capable of forming a Lewis acid and a cationic polymerization active species is used as a polymerization initiator system to prepare isobutylene. After polymerizing to form the polymer block (B), a vinyl aromatic monomer is then added to carry out polymerization to form the polymer block (A).

The A / B block copolymer shows the same degree of strength and elongation as the vulcanized rubber without cross-linking because the polymer block (A) made of a vinyl aromatic monomer forms a pseudo cross-linking point. . Further, since the polymer block (B) made of isobutylene is present, it also has a property as an elastic body. Furthermore, the A / B block copolymer has excellent vibration damping performance (vibration absorption) and is also excellent in various properties such as mechanical properties, heat resistance, light resistance, and dimensional stability.

The block copolymer composition used in the present invention may be composed of only the above A / B block copolymer, or may contain other components as required. For example, by containing various oils, the processability of the block copolymer composition is improved, and the temperature range in which good vibration damping performance (vibration absorption) is exhibited can be changed. As usable oils, for example,
Paraffin oil, naphthene oil, aromatic oil and the like can be mentioned. Further, other oils can be used as long as they have good compatibility with the A / B block copolymer and do not significantly deteriorate the processability, but considering the temperature during baking coating on metal. ,
Those having good heat resistance are preferable. For example, a naphthenic oil such as "Sunthen 250" manufactured by Sun Oil Co. is preferable. The content of oil is preferably 5 to 60 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the block copolymer used in the present invention. If the oil content is less than 5 parts by weight, the workability is not sufficiently improved. On the other hand, if it exceeds 60 parts by weight, the oil bleeds, which is not preferable.

The block copolymer composition used in the present invention may contain various fillers, if necessary. As the filler, for example, mica, carbon black, silica, calcium carbonate, talc, graphite,
Examples thereof include powder fillers such as stainless steel and aluminum; fibrous fillers such as glass fibers and metal fibers. Among them, mica is preferable because it has an effect of improving vibration damping performance (vibration absorption) and heat resistance. Further, spot welding can be performed by incorporating various metal powders such as stainless powder and aluminum powder, metal fibers, or conductive particles such as carbon black and graphite. The content of the filler is preferably 20 to 150 parts by weight with respect to 100 parts by weight of the block copolymer used in the present invention. When it is desired to improve the vibration damping performance (vibration absorbing property) by adding mica, it is preferable to contain 30 parts by weight or more.

If desired, a tackifier may be added to the block copolymer composition used in the present invention for the purpose of enhancing the adhesive strength with a metal. Examples of the tackifier include various resins such as coumarone resin, phenol resin, terpene resin, and petroleum hydrocarbon resin. The shear adhesive strength is improved by containing the tackifier. Other tackifying resins can be used as long as they have good compatibility with the block copolymer and do not deteriorate processability.

Further, if necessary, within a range not impairing the performance of the block copolymer composition used in the present invention,
It may contain other polymers. Examples of other polymers include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber,
Butyl rubber or low molecular weight isobutylene, isoprene and butadiene rubber, isoprene-butadiene copolymer, further aromatic vinyl-conjugated diene block copolymer and hydrogenated product thereof, ethylene-vinyl acetate copolymer,
Examples thereof include thermoplastic resins such as polyamide and polyester, and thermoplastic polyurethane. The content of these polymers is preferably about 30 parts by weight or less based on 100 parts by weight of the block copolymer used in the present invention.

The block copolymer composition used in the present invention has thermoplasticity and can be easily molded by hot melt. That is, kneading with a kneader,
A molded product is obtained by cooling after molding by pressing or the like or kneading and molding by an extruder.

Composite (preferably laminated) of a metal and a molded article composed of the block copolymer composition used in the present invention
Is a method in which the block copolymer composition is formed into a film and then sandwiched in a heated metal, a method in which the molten block copolymer composition is coated and sandwiched in a metal using a roll coater, or The block copolymer composition is melt extruded and sandwiched between the metals.

The metal used in the present invention is not particularly limited, but examples thereof include cold rolled steel plate, carbon steel plate, stainless steel plate and low alloy steel plate. Further, examples of the metal plate other than the steel plate include an aluminum plate and the like.

The vibration-damping metal composite of the present invention is required to have vibration-damping performance (vibration absorbing capacity) and noise-vibration resistance, housing-related products, various electric products, office equipment, machine parts, automobile parts. It can be used effectively in

[0026]

EXAMPLES The present invention will now be described in detail with reference to Examples, but the present invention is not limited thereto. In the following examples, the number average molecular weight of the block copolymer was measured by the GPC method, and the content of units derived from styrene in the block copolymer was determined by ¹ H-NMR.
The shear adhesive strength between the molded product made of the block copolymer composition and the metal was measured according to JIS K6850.
In addition, the mechanical loss coefficient (tan
δ) was measured according to the following method.

[Mechanical Loss Coefficient (tan δ)] The mechanical loss coefficient (tan δ) of the metal composite obtained in each example was measured by a resonance method using a cantilever. Generally, the mechanical loss coefficient (tan δ) is used as a parameter indicating the vibration damping performance (vibration absorption), and the larger this value, the better the vibration damping performance (vibration absorption).

Production Example 1 800 ml of methylene chloride and 12 of methylcyclohexane were used as a solvent in a reactor equipped with a stirrer, which was replaced with nitrogen.
00 ml, 4.3 g of titanium tetrachloride (Lewis acid) and 0.33 g of 1,4-bis (2-methoxy-2-propyl) benzene were charged as a polymerization initiator system, and 240 g of isobutylene was charged at -65 ° C for 4 hours. After the polymerization, 0.13 g of dimethylacetamide and 60 g of styrene were added, and the mixture was further polymerized for 4 hours to produce a styrene-isobutylene-styrene triblock copolymer. The number average molecular weight of the obtained triblock copolymer, the number average molecular weight of the styrene block, the number average molecular weight of the isobutylene block,
The styrene content and tan δ at 0 ° C are shown in Table 1 below. Also, using the same method, the number average molecular weight, styrene content and tan δ at 0 ° C. shown in Table 1 were used.
A styrene-isobutylene-styrene triblock copolymer having and was prepared.

[0029]

[Table 1]

Examples 1 to 7 and Comparative Example 1 Triblock copolymers obtained in the above Production Examples were used to prepare triblock copolymer compositions having the compounding ratios shown in Table 2 below. Width 2.5 cm, thickness 0.8
A metal composite was produced by sandwiching a 0.02 mm thick cold rolled steel sheet with a thickness of 0.02 mm. The obtained metal composite was measured for tan δ and shear adhesive strength, and the results are also shown in Table 2. In Example 5 in which the ethylene-vinyl acetate copolymer was blended and Example 6 in which the alicyclic saturated hydrocarbon resin was blended, the improvement of the adhesive force with the metal was observed.
Further, the metal composites of Examples 5 and 6 and Comparative Example 1 were subjected to a bending test (R = 4 mm) to examine peeling and protrusion of the elastomer. As a result, peeling occurred in Comparative Example 1, but Example 5 6 and 6, neither peeling nor squeeze out occurred.

[0031]

[Table 2]

[0032]

EFFECTS OF THE INVENTION A molded article made of the block copolymer composition of the present invention and a vibration-damping metal composite made of a metal have excellent vibration-damping performance (vibration absorption), and a metal diaphragm,
It can also be used for bending.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mizuho Maeda 36 Towada, Kamisu-cho, Kashima-gun, Ibaraki Prefecture Kuraray Co., Ltd.

Claims (1)

[Claims] 1. A number average molecular weight of 20,000 to 5 comprising the following polymer block (A) and polymer block (B):
A molded article made of a composition containing 00000 block copolymer, and a vibration-damping metal composite made of a metal. (A) Number average molecular weight of vinyl aromatic monomer 25
Polymer block of 00-400000. (B) Number average molecular weight of isobutylene 10,000 to 10,000
400000 polymer blocks.