JP2511477B2 - Viscoelastic composition for damping metal plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a viscoelastic composition for a vibration damping metal plate having excellent post-processability, and more specifically, a component of an intermediate layer sandwiched between two metal plates. As a rubber component having an unsaturated bond, a viscoelastic composition containing an acrylic acid metal salt or a methacrylic acid metal salt, and a polymerizable monomer as a main component, a vibration-damping metal plate having this as an intermediate layer Allows post-processing such as overhanging, bending, and deep drawing to be performed extremely well, and can be used in vehicles such as automobiles, railways, airplanes, office equipment, electrical appliances, etc., in a temperature range of 0 to 100 ° C, especially near room temperature. It is possible to obtain a vibration-damping metal plate having excellent vibration-damping properties, which reduces the noise of the vibration member.

2. Description of the Related Art In recent years, along with the spread of vehicles such as automobiles, railroads and airplanes, office equipment, and electrical products, noise countermeasures against such equipment have been highlighted as an urgent issue. Metal plates have been proposed or marketed.

However, when the conventional vibration-damping metal plate is evaluated in response to market demands, the following various deficiencies are raised, and as a result, the applicable range is very limited.

One of the biggest drawbacks is that most of the intermediate layer materials used in commercially available vibration-damping metal sheets are thermoplastic self-adhesives, so they are subject to impact stress during post-processing. , Cracks in the material of the intermediate layer,
Buckling is likely to occur during contraction deformation, and flange wrinkles are likely to occur. Furthermore, because the adhesion to metal is extremely poor,
Peeling off from the metal plate and misalignment occur. Therefore, it is very difficult to carry out press molding in which overhanging, bending, drawing and the like are combined. In other words, it is difficult to apply it to automobile members, office equipment, metal working equipment, etc., which are in great demand and require complicated press formability.

In addition, even for members made by very simple press molding, the intermediate layer material flows out during the baking process or drying process of the paint, decomposition carbonization occurs, and further, creep occurs under static stress at the actual operating temperature. In addition, various problems occur in practice, such as peeling from a metal plate.

OBJECT OF THE INVENTION The object of the present invention is to provide a viscoelastic composition for use in a vibration damping metal plate having both the vibration damping ability and the excellent post-processability, which are improved by the above-mentioned drawbacks of the conventional vibration damping metal plate. Especially.

That is, as a result of intensive studies by the present inventors, a natural rubber or a synthetic rubber 10 having an unsaturated bond in the molecule was obtained.
1 to 90 parts by weight of acrylic acid metal salt or methacrylic acid metal salt, 25 to 200 parts by weight of a polymerizable monomer other than acrylic acid metal salt and methacrylic acid metal salt, and further adhesiveness to 0 part by weight A viscoelastic composition for a vibration-damping metal plate comprising 50 to 200 parts by weight of an agent and 0.1 to 10 parts by weight of a catalyst was found, and the present invention has been completed thereby.

Structure of the Invention The gist of the present invention is to provide a viscoelastic composition for a vibration damping metal plate, which is sandwiched between metal plates to form an intermediate layer and is cured and integrated, wherein (A) an unsaturated bond is present in the molecule. To 100 parts by weight of a natural rubber or a synthetic rubber having one or a mixture of two or more kinds thereof, (B) a metal salt of acrylic acid or a metal salt of metacrylic acid is added.
~ 90 parts by weight, and (C) a polymerizable monomer and a compound other than the component (B) 25 to 20
Viscoelasticity for vibration-damping metal plates with excellent post-processability by loading 0 parts by weight, (D) 50 to 200 parts by weight of tackifier, and (E) 0.1 to 10 parts by weight of curing catalyst. It relates to a composition.

Further, as the above composition, the viscosity is 10,000 poise or less when the viscosity is 30 ° C. and the shear rate is 1,000 sec ^{−1 in} the state before curing, and the composition has tackiness, and the physical properties of the intermediate layer after curing are 10
Storage elastic modulus (E ') is 10 ⁷ in the temperature range of up to 100 ° C.
〜5 × 10 ⁹ dyne / cm ² , viscoelastic property of loss tangent (tan δ) of 0.1 or more, and the adhesion performance of the two metal plates to the intermediate layer, the peeling force is 5kg / 25mm or more The present invention relates to a viscoelastic composition for a vibration damping metal plate, which has an excellent shearing force of 30 kg / cm ² or more and an excellent adhesive force.

Next, each material of the viscoelastic composition of the present invention will be described in detail.

The rubber-like polymer used in the present invention includes natural rubber, polyisobutylene, polybutadiene, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, styrene-butadiene-vinylpyridine copolymer, isobutylene-isoprene copolymer. Combined, acrylic acid-butadiene copolymer, methacrylic acid-
Butadiene copolymer, methyl acrylate-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-propylene-cyclopentadiene copolymer, ethylene-propylene-5-ethylidene-2-norbornene copolymer, ethylene-propylene- 1,4-hexadiene copolymer, conjugated diene butyl rubber, syndioctatic 1,2-polybutadiene, norbornene rubber, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, etc. It is a wide range of polymer elastomers having a bond. The molecular weight of these high molecular weight substances is not limited at all, and may be appropriately selected and used depending on the purpose of use or conditions of use, but those having a molecular weight of about 500 or more mainly for the purpose of maintaining the physical properties of the starting polymer elastomer. Is preferably used. Further, two or more polymers may be used in combination.

The acrylic acid metal salt or methacrylic acid metal salt used in the present invention is a reaction product of a metal oxide such as zinc, aluminum, tin, calcium, nickel, cobalt, iron, magnesium and lead with acrylic acid or methacrylic acid. There are zinc acrylate, aluminum acrylate, cobalt acrylate, lead acrylate, magnesium acrylate, tin acrylate, calcium acrylate,
There are metal salt compounds such as zinc methacrylate, aluminum methacrylate, cobalt methacrylate, lead methacrylate, magnesium methacrylate, tin methacrylate, iron methacrylate, etc. These compounds give excellent adhesion to the metal surface. To do.

Styrene derivatives such as styrene, α-methylstyrene, β-methylstyrene, and divinylbenzene as the polymerizable monomer; acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, dodecyl methacrylate, cyclohexyl methacrylate, methacrylic acid. Tetrahydrofurfuryl, lauryl methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, stearyl methacrylate, diethylaminoethyl methacrylate, ethyl dimethacrylate, 1,3-butylene glycol dimethacrylate, 2-hydroxyethyl methacrylate, Acrylic acid derivatives and methacrylic acid derivatives such as ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate and tri-methylolpropane triacrylate; triallyl isocyanurate Examples thereof include rate, vinyl acetate / acrylonitrile, vinyl pyridine, and the like, and at least one of them is used, which makes it possible to design in a wide range of vibration damping ability and mechanical properties.

The pressure-sensitive given whenever agent used in the present invention, rosin, hydrogenated rosin glycerin ester, polyterpene resin, terpene phenol resins, C ₅ petroleum resins, C ₉ petroleum resins,
Solid quasi-polymer resins such as aliphatic cyclic hydrocarbon resins and hydrogenated hydrocarbon resins; fluid quasi-polymer resins such as xylene resins, epoxy resins, unsaturated polyester resins, polyacrylic acid esters; phthalate esters, Examples include plasticizers such as aromatic polybasic acid esters and aliphatic dibasic acid esters, and high molecular weight low polymers such as polybutene and polyisobutylene.At least one of them is used, which exhibits vibration damping ability. It is possible to freely design the temperature range to be applied.

Further, the curing catalyst used in the present invention includes ketone peroxides such as methyl ethyl ketone peroxide, cyclohexane peroxide and acetylacetone peroxide; 1,1-bis (tertiary-butyl peroxide) -3,3,5. -Trimethylcyclohexane, 1,1-bis (tertiary-butyl peroxide) -cyclohexane and other peroxyketals; tertiary-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5 -Hydroperoxides such as dihydroperoxide; dialkyl tertiary oxides such as di-tertiary-butyl peroxide and dicumyl peroxide; diacyl peroxides such as acetyl peroxide, isobutyl peroxide and benzoyl peroxide; diisopropyl peroxide Siji carbonate, peroxydicarbonate such as dimyristyl peroxydicarbonate; tert - butylperoxy acetate,
Examples thereof include peroxyesters such as tertiary-butylperoxybenzoate, tertiary-butylperoxymaleic acid, and tertiary-butylperoxyisopropyl carbonate, and at least one peroxide of these curing agents is used. To be

The objects of the present invention can be achieved by mixing and integrating the materials described above, sandwiching them between two metal plates, heating and curing them, and integrating them.

The vibration-damping metal plate using the viscoelastic composition of the present invention has very good adhesion between the intermediate layer and the two metal plates and has excellent vibration damping property, and further has thermal stability,
Since it has excellent heat aging resistance and impact resistance, spot welding for reinforcement is not necessary, and it greatly contributes to productivity.

However, in the case of combining the vibration damping metal plate of the present invention and another metal member, it is necessary to impart conductivity to the viscoelastic composition, and in that case, iron, aluminum,
Copper, stainless steel or other metal powder or carbon black, conductive particles such as carbon fiber, conductive short fibers and the like are added to 1 to 50 parts by weight with respect to 100 parts by weight of the viscoelastic composition to perform good spot welding. Can be tightened.

In addition, a polymerization inhibitor, a curing accelerator auxiliary agent, and an anti-aging agent can be added to the viscoelastic composition used in the present invention, if necessary, and other fillers and the like can be added.

On the other hand, the two metal plates used in the present invention are iron,
It is a steel sheet plated with various alloys such as copper, aluminum, duralumin, and stainless steel, or plated with zinc, chromate, zinc phosphate, etc., and these are used in combination with the same or different metals.

The thickness of the intermediate layer sandwiched between the metal plates is adjusted to 0.01 to 1.0 mm, preferably 0.05 to 0.5 mm.

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples.

Example-1 100 parts by weight of polybutadiene rubber (BR-01 manufactured by Japan Synthetic Rubber Co., Ltd.) as a rubber-like polymer and 87.5 parts by weight of an acrylic ester which is compatible with the rubber-like polymer as a polymerizable monomer in the same container I put it in a bowl and left it all day and night. As the acrylic ester, three kinds of methyl methacrylate, cyclohexyl methacrylate and 1,3-butylene glycol dimethacrylate were used. 50 parts by weight of zinc acrylate is added to each mixture, and an alicyclic hydrocarbon resin (Arakawa Chemical Industry Co., Ltd.
-100) and 150 parts by weight of t-butylperoxymaleic acid as a curing catalyst were added and mixed by a kneader to obtain a viscoelastic composition of a viscous material. The content of the formulation is as shown in Table 1. The composition before curing was measured for viscosity, and the composition after curing was measured for adhesive strength and viscoelastic property, and further vibration damping property.

The material viscosity flow tester apparatus, the viscosity was measured at a shear rate 10sec ^-1 ~5 × 10 ³ sec ^-1 at a temperature 30 ° C.. Further, the adhesive strength was measured by sandwiching the composition between 0.8 mm cold-rolled steel sheets and heating and pressurizing at a temperature of 150 ° C. for 10 minutes to prepare a test piece.

Shear adhesion is JIS-K-6850, peel adhesion is JIS-K-
Measured according to 6854.

Adhesiveness was measured by using a vibron tester for a sheet-shaped test piece that had been heat-cured at 150 ° C for 10 minutes in the temperature range of -100 ° C to 150 ° C.
δ) was measured. The maximum value of tan δ at a frequency of 100 Hz and E'at that temperature were measured.

Furthermore, the vibration damping property is such that the thickness of the intermediate layer of the viscoelastic composition is 0.1 mm between the secondary steel plates having a thickness of 0.8 mm, a width of 25 mm and a length of 300 mm.
The test piece that was adjusted to 1, and cured and integrated under the conditions of heating and pressurization at 150 ° C for 10 minutes was used, and the mechanical impedance method was used to measure the loss coefficient (η), which is a measure of vibration damping capacity, at a frequency of 500 Hz. The temperature dependence at was measured. The results are shown in FIGS. 2 and 1.

Comparative Examples-1 and 2 For comparison, a conventional vibration-damping metal plate containing polyisobutylene as a main component and a conventional vibration-damping steel plate containing ethylene-vinyl acetate as a main component were designated as Comparative Examples 1 and 2, respectively, and their adhesive strength and Vibration damping performance was measured. The result is the second,
It was as shown in FIG.

From the above results, the viscoelastic composition of Example was excellent in vibration damping performance and excellent in adhesive performance as compared with Comparative Example.
Although Comparative Example 1 is excellent in vibration damping performance, it is inferior in adhesion performance. Comparative Example 2 is inferior in both vibration damping performance and adhesive performance.

Example-2 3 as a rubber-like polymer: styrene-butadiene rubber, acrylonitrile-butadiene rubber, and isoprene rubber
100 parts by weight of each kind and 87.5 parts by weight of acrylic ester were put in the same container and left to stand for a day and night to swell.

As the acrylic ester, 1,3 butylene glycol dimethacrylate was used. A zinc acrylate tackifier and a curing catalyst were added to each mixture in the contents shown in Table 3 and mixed to obtain a viscous composition. With respect to these compositions, the viscosity of the pre-curing material, the adhesiveness of the post-curing material, the viscoelastic property, and the vibration damping property were measured under the same conditions as in Example-1, and the results are shown in Table 4.

By selecting the rubber-like polymer type, it is possible to design the operating temperature for damping performance.

Example-3 As shown in Table 5, a viscoelastic composition was prepared by changing the kinds of the acrylic acid metal salt and the methacrylic acid metal salt, and Example-1 was prepared.
Measurement of the viscosity of the material before curing under the same conditions as shown in
The adhesive property, viscoelastic property, and vibration damping property of the cured material were measured, and the results are shown in Table 6 and FIG. The adhesion test was performed using two types of cold rolled steel sheets and galvanized steel sheets.

In the comparative example, a composition containing no metal acrylate was used as comparative example-3, and the performance was evaluated under the same test conditions. As shown in Table 6, the system in which no metal salt was added had good vibration damping performance, but poor adhesion performance.

Example 4 A material produced by uniformly mixing 20 parts by weight of iron powder (particle size: 75 μ or less) with 100 parts by weight of the viscoelastic composition of Example-1, test number-3 was designated as test number-12. . The composition was sandwiched between two cold-rolled steel sheets having a thickness of 0.6 mm and then heat-cured to perform spot welding on a vibration-damped metal sheet.

The welding equipment is a spot welding machine manufactured by Osaka Electric Co., Ltd., which is a one-point spot welding of 1.2 mm thick steel plates under the condition of class A welding, and is a vibration damping metal plate welding.

The nugget portion formed in the spot welding did not contain residual intermediate layer, and the shearing force after the spot welding was 255 kg / cm ² , and the spot welding of the vibration damping metal plates was good.

Test No.-12 polybutadiene rubber 100 parts by weight 1,3-butylene glycol dimethacrylate 87.5 〃 zinc acrylate 50 〃 alicyclic petroleum resin 150 〃 t-butylperoxymaleic acid 2.5 〃 p-benzoquinone 0.02 parts by weight iron powder 78〃 Shear adhesion Before welding 128kg / cm ² After welding 255kg / cm ² Example-5 As rubber-like polymer, two kinds of styrene-butadiene-styrene block copolymer and styrene-isoprene-styrene block copolymer were used. Put 120 parts by weight of acrylic ester in the same container,
It was left to stand for a whole day and night to swell. As the acrylic ester, 60 parts by weight of methyl methacrylate and 60 parts by weight of cyclohexyl methacrylate were used. Zinc acrylate, a tackifier, and a curing catalyst were added to and mixed with each mixture as shown in Table 7 to obtain a viscous composition. With respect to these compositions, the viscosity of the pre-curing material, the adhesiveness of the post-curing material, the viscoelastic property, and the vibration damping property were measured under the same conditions as in Example-1, and the results are shown in Table 8.

As is clear from the results of Table 8, it is possible to freely design the operating temperature of the vibration damping performance by appropriately selecting the rubber type of the block copolymer and the styrene / rubber ratio.

[Brief description of drawings]

In the accompanying drawings, FIG. 1, FIG. 2 and FIG. 3 are graphs showing the results of measuring the temperature dependence of the loss coefficient for the viscoelastic composition for vibration damping metal plates according to the present invention.

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Claims (3)

(57) [Claims] 1. An intermediate layer formed by sandwiching between metal plates,
A viscoelastic composition for a vibration-damping metal plate, which cures and integrates, wherein 100 parts by weight of natural rubber or synthetic rubber having an unsaturated bond in the molecule as component (A), and metal acrylate as component (B) Alternatively, 1 to 90 parts by weight of a metal methacrylic acid salt, 25 to 200 parts by weight of a compound other than the component (B) which is a polymerizable monomer as the component (C), and 50 to 50 parts of the tackifier as the component (D). A composition comprising 200 parts by weight and 0.1 to 10 parts by weight of a catalyst as the component (E). 2. The composition of claim 1, wherein the viscosity of the composition before curing is 10,000 poise or less at a shear rate of 1,000 sec ^-1 at a temperature of 30 ° C. and is tacky. The composition as described. 3. The characteristics of the composition after curing are 0 to 100 ° C.
A) storage elastic modulus (E ′) is 10 ^{7 to} 5 × 10 ⁹ dyne / cm ² , b) loss angle tangent (tan δ) is 0.1 or more, and c) peel adhesion strength with a metal material The composition according to claim (1), which has a physical property value of 5 kg / 25 mm or more and a shear adhesion force of 30 kg / cm ² or more.