JPH08444B2 - Composite type damping material capable of spot welding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite vibration damping material capable of spot welding, and more particularly, to a metal composite material constituting an electric component, a component of a machine or a structure, or a part thereof. The present invention relates to a vibration damping material that absorbs vibrations, has conductivity, and can perform spot welding.

[0002]

2. Description of the Related Art Today, where energy saving is required, lightweight steel sheets are required for use in vehicle bodies and parts in order to reduce the weight in the field of transportation of automobiles and vehicles. And, in order to promote this weight reduction, it is essential to reduce the plate thickness of the member itself by using high-strength steel, etc., but if this plate thickness is reduced, there is a problem that rigidity decreases, It is easy to vibrate and may cause problems such as noise. Therefore, in order to reduce this noise, a composite damping material has been proposed in which an intermediate layer of synthetic resin is sandwiched between two metal layers to form a so-called three-layer structure, and the intermediate resin layer absorbs vibration. . In this case, iron, copper, aluminum, or an alloy containing them as one component is used as the material forming the metal layer, and various steel materials or plated steel sheets are particularly commonly used. Surface-treated steel sheets such as

Such a composite type vibration damping material has a characteristic that it is excellent in vibration damping performance, but if the advantages inherent to the metal material itself such as strength, toughness and press workability are impaired. The value is also halved. Therefore,
Such a composite metal material has a press workability equivalent to that of a single metal material, that is, a high adhesive strength, and a temperature of about 180 ° C. which is equivalent to a baking line in a painting process. It is also required that the intermediate layer resin does not flow out even if it is exposed to a high temperature, and that the adhesive strength is extremely reduced and the processed end surface does not open. Among the above-mentioned required characteristics, it is extremely effective that the resin for the intermediate layer is crosslinked with respect to improvement of the adhesive strength, adhesive strength at high temperature, outflow of the resin for the intermediate layer, and the like.

By the way, even when the metal composite material has an insulating resin intermediate layer, for example, in Japanese Utility Model Publication No. 52-55,466.
Although spot welding can be performed by using an auxiliary electrode as seen in No. 6, the welding process is complicated in this case, and it is difficult to use on-line in various component manufacturing processes. Therefore, in the past, as an attempt to electrically conductive the intermediate layer of the metal composite material and impart electric spot weldability, a method of filling a conductive filler (JP-A-50-
79,920, JP-A-53-128,687, JP-A-56-31,540, JP-A-57-146,649.
JP-A-57-163,559 and JP-A-57-16
3,560, JP 61-40,150, JP 6
No. 1-41,540), a method of sandwiching a metal net (JP-A-58-132,550), and a method of forming a deformed pattern on a metal plate (JP-A-58-197,045).
No. 59-103,748 and 59-1.
No. 45,142).

In the conventional composite vibration damping material capable of spot welding, the method of sandwiching the metal net complicates the work at the time of manufacturing the vibration damping steel plate and affects the press workability. The method of applying a pattern also requires the processing of the steel plate before the production of the vibration-damping steel plate, and there is a problem that a pattern appears on the surface of the vibration-damping steel plate as a product. Further, the method of filling the conductive filler is an excellent method in terms of process, but as described above, if the intermediate layer resin is cross-linked to improve the properties of the vibration-damping steel sheet, the spot weldability decreases with time. To do. That is, even after the spot welding was possible immediately after the production of the vibration-damping steel sheet, as the time after the production passed, a short circuit was formed at a point other than the welding point, and the outer layer metal material had holes, or sparks were broken. In many cases, it becomes impossible to energize and spot welding cannot be performed at all. This behavior is hardly observed when the intermediate resin layer is not crosslinked, and it may be possible to manufacture a composite type damping material that can be spot welded by any of the conventional techniques. When the layers were cross-linked, it was not possible to produce materials in the prior art whose spot weldability did not deteriorate over time.

[0006]

SUMMARY OF THE INVENTION The present invention was devised in view of this point of view. In order to improve the properties of the composite vibration damping material, a conventional metal plate is used even in a system in which an intermediate resin layer is crosslinked. The present invention provides a composite vibration damping material that can be equally spot-welded, stably exhibits its spot-weldability, and shows no change over time.

[0007]

That is, according to the present invention,
In the vibration damping material in which the resin layer is provided between the metal plates, the maximum value of the loss tangent (tan δ) based on the glass transition is 0.
The temperature that is 5 or more and exhibits this maximum value is -40 to 120
The cross-linked resin between 0 ° C is used as the intermediate layer resin and is softer than the outer layer metal material and has a ratio (D / T) of the maximum particle size (D) to the total thickness (T) of the intermediate layer of 1 to 2. This is a spot-weldable composite damping material in which 1 to 100 parts by weight of certain metal particles are mixed with 100 parts by weight of the intermediate layer resin.

The present invention will be described in detail below. First, in the present invention, the resin in the resin composition that is sandwiched between the outer metal materials to form the resin intermediate layer and imparts the vibration damping performance to the composite material is −80 to 120 ° C., preferably −40 to 120 ° C.
Loss tangent (ta) at the glass transition point at 120 ° C
A viscoelastic resin having a maximum value of nδ) of 0.5 or more, preferably 0.7 or more is good.

As the viscoelastic resin satisfying such conditions, polystyrene, AS resin, ABS resin, MS resin, styrene-based resin such as impact-resistant polystyrene, polymethyl acrylate, polymethyl methacrylate, etc. Acrylic resin such as polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, vinyl chloride / acrylic acid ester copolymer, etc., Vinyl acetate resins such as polyvinyl acetate, polyvinyl formal, and polyvinyl butyral,
Ethylene-based polymers such as ethylene / α-olefin copolymers, ethylene / vinyl acetate copolymers, ethylene / acrylic acid copolymers, ethylene / methacrylic acid ester copolymers, and ethylene / methacrylic acid copolymers Examples thereof include resins, propylene-based resins such as propylene / ethylene copolymers and propylene / butene copolymers, various types of thermoplastic resins such as amorphous polyamides such as copolymerized nylon, and amorphous polyesters. In addition, elastomers such as styrene / butadiene rubber, natural rubber, butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, acrylic rubber, ethylene / acrylic rubber, EPDM, epoxy resin, phenol resin, unsaturated polyester resin, etc. Thermosetting resins can also be used. These resins can be used alone or in combination of two or more. In addition, these resins are appropriately selected from the viewpoints of performance required for the composite vibration damping material, such as vibration damping, heat resistance, workability, oil resistance, and cold resistance.

The above intermediate layer resin composition serves as an intermediate layer of the composite type vibration damping material so that the intermediate layer resin composition does not easily flow out even when exposed to a high temperature such as a baking coating line. This intermediate layer needs to be crosslinked in order to improve the shear bond strength, which has an important influence on the press workability. The crosslinking agent used for this purpose can be appropriately selected depending on the functional group of the intermediate layer resin, and examples thereof include sulfur, organic sulfur compounds, alkylphenol-formaldehyde resins, and heat-reactive phenolic resins. Resin vulcanizing agents, polyamines, polyols, organic peroxides, amino resins, isocyanates, epoxies, polyamidoamines, acid anhydrides and the like, and any crosslinking accelerator as required. , An activator, a crosslinking retarder, and the like. Further, when a mixture of two or more kinds of polymer substances is used as the intermediate layer resin, it is not always necessary that all components are crosslinked, and at least one component may be crosslinked.

Further, among the above-mentioned resin cross-linked products, the performance required for the composite type vibration damping material, for example, the vibration damping property,
From the viewpoints of heat resistance, processability, adhesiveness with metal materials, oil resistance, etc., one component of the resin crosslinked product has a maximum value of loss tangent (tan δ) based on glass transition of 0.5 or more, and shows this maximum value. A crosslinked amorphous polyester having a temperature of -40 to 120 ° C is preferable.

As such an amorphous polyester,
Crystalline saturated polyesters such as polyethylene terephthalate and polybutylene terephthalate are dissolved in ethylene glycol at high temperature to give triethylene glycol, 1,4-butanediol, neopentyl glycol, etc. It can be synthesized by adding saturated polyhydric alcohol and transesterification reaction, or can also be synthesized by copolymerizing saturated polyhydric carboxylic acid and saturated polyhydric alcohol. The latter saturated polycarboxylic acid is terephthalic acid,
Examples include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, trimellitic anhydride, and the like. As the saturated polyhydric alcohol, ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, Examples include polyethylene glycol, neopentyl glycol, propylene glycol, 1,4-cyclohexane dimethanol, pentaerythritol, trimethylol propane and the like. There are many combinations of these monomers, and they are appropriately selected depending on the desired melting point, glass transition temperature, degree of amorphousness and the like. These amorphous polyesters may be used alone or in combination of two or more.

The cross-linking agent for cross-linking the amorphous polyester may be any one that reacts with the terminal functional group of the polyester. For example, when the terminal functional group of the polyester is a carboxyl group, amine, isocyanate, epoxy, etc. When the terminal functional group of the polyester is a hydroxyl group, compounds such as amines, isocyanates, acid anhydrides, epoxies, chlorine, etc. and silane coupling agents are exemplified, as well as organic peroxides. A radical generator effective for effective three-dimensional crosslinking may be used.

Next, the metal particles that are mixed with the intermediate layer resin to form the resin composition must be softer than the outer layer metal material, and differ depending on the type of outer layer metal material. . When the metal particles are harder than the outer layer metal material, the spot weldability becomes unstable when the intermediate layer resin is cross-linked even if the particle size satisfies the following conditions. As the metal particles softer than the outer layer metal material, for example, when the outer layer metal material is a cold rolled steel sheet, copper, nickel, aluminum, lead, zinc, etc. which are softer than the steel sheet as the conductive particles, and alloys of these metals are used. Examples thereof include metal particles. These metal particles can be used alone or in combination of two or more.

These metal particles must have a ratio (D / T) of the maximum particle diameter (D) to the total thickness (T) of the intermediate resin of 1 to 2. The maximum particle size referred to here is the opening size of the sieve when the metal particles are sieved. This sieve has a mesh size that is smaller than the maximum particle size of the metal particles before sieving.The particle size distribution of the metal particles is usually a log-normal distribution, and particles with particle diameters near the sieve mesh are Exists to some extent. When D / T is less than 1, stable spot weldability cannot be obtained, and when D / T exceeds 2, the adhesive strength between the metal material and the resin layer decreases. D /
The value of T is determined by the balance between spot weldability and adhesiveness.
More preferably D / as the region that does not reduce the adhesive strength
T is 1 to 1.5.

The amount of these conductive particles to be blended must be 1 to 100 parts by weight with respect to 100 parts by weight of the resin.
It is preferably 1 to 50 parts by weight, more preferably 1 to 10 parts by weight. If the content is less than 1 part by weight, stable spot weldability cannot be obtained, and if it exceeds 100 parts by weight, the adhesion between the metal layer and the intermediate resin layer is deteriorated. Further, the intermediate resin layer of the vibration-damping steel sheet capable of spot welding of the present invention may be not only a single layer but also a multilayer. In the case of a multilayer, the metal particles have the maximum particle diameter (D) and the total thickness (T) of the resin multilayer body. What satisfies the above condition may be blended only in the central layer of the multilayer body.

The method for producing the composite type vibration damping material of the present invention is not particularly limited. For example, as a method for adhering a metal layer and a resin layer, a resin composition is provided between two metal layers. Examples include a method of sandwiching and thermocompression bonding at a temperature equal to or higher than the melting point of the resin composition, or a method of applying a solution of the resin composition to two metal layers, drying the two to remove the solvent, and then laminating them.

[0018]

According to the present invention, in the composite type vibration damping material, by blending the softer metal particles than the outer layer metal material in the intermediate resin layer, the metal particles are plastically deformed when coming into contact with the outer layer metal material, and the upper and lower outer layer metal materials are deformed. Even if it is a composite type vibration damping material in which the material is electrically short-circuited and the intermediate resin layer is cross-linked, stable spot weldability that does not change with time can be imparted.

[0019]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples.

In both the examples and the comparative examples, the viscoelastic resin composition has a maximum loss tangent (tan δ) of 1.31 based on the glass transition measured by a dynamic viscoelasticity measuring apparatus in a shear mode of 110 Hz, which is the maximum. An amorphous polyester having a temperature of 11.1 ° C. and a molecular weight of 15,000 to 20,000;
A 2: 1 mixture (hereinafter, resin A) with an amorphous polyester having a loss tangent (tan δ) of 1.39 and a maximum value of 37.7 ° C. and a molecular weight of 15,000 to 20,000,
And the loss tangent (tan δ) based on the glass transition is 1.
Based on glycidyl methacrylate / methyl acrylate / ethyl acrylate copolymer (hereinafter referred to as resin B) having a temperature of 50 ° C. which exhibits this maximum at 50 ° C. , and glass transition
The maximum value of the loss tangent (tan δ) is 1.35, and this maximum is
The temperature shown is 55.0 ° C, the molecular weight is 15,000 to 20,0.
00 amorphous polyester (hereinafter referred to as resin C) was used. A cross-linking agent was added as needed to obtain a resin composition.
The crosslinking agent used at this time had an isocyanate group content of 13.2 per 100 parts by weight of the amorphous polyester mixture.
% Trifunctional isocyanate (hereinafter referred to as a cross-linking agent A), 5 parts by weight of pyromellitic dianhydride, and an epoxy equivalent of 1
90 parts by weight of 90 bisphenol A type epoxy resin (hereinafter, crosslinking agent B) acrylate copolymer (resin B)
5 parts by weight of hexamethylenediamine (hereinafter referred to as a cross-linking agent C) was added to 100 parts by weight.

Regarding the metal particles, those of the types shown in Tables 1 and 2 were passed through a sieve of respective meshes, classified to a maximum particle size or less, and added in a predetermined amount.

The above composition was applied to two cold-rolled steel sheets having a thickness of 0.8 mm and dried, and the two sheets were bonded together.
It was thermocompression bonded at 180 ° C. and 5 kg / cm ² for 5 minutes, and then subjected to a cooling press to produce a composite vibration damping material. Tables 1 and 2 show the results of a spot welding test performed on the composite vibration damping material obtained by the above method and a cold rolled steel sheet having a thickness of 0.8 mm. The spot welding test was performed under the conditions of an activation pressure of 250 kg, a passing current of 6.4 kA, and an energization time of 14 cycles.

In Table 1, the thickness (T) of the intermediate resin layer is 60 μmT, the hardness of the cold-rolled steel sheet is 4.5 or more in Mohs hardness, and in Vickers hardness (Hv). 90
˜162 (reference value), and * marks in Table 1 are as follows. * 1: Resin A: Amorphous polyester Resin B: Acrylic ester copolymer * 2: Crosslinking agent A: Trifunctional isocyanate (-NCO content 13.2%) 10 parts by weight (Resin A 100 parts by weight) Crosslinking agent B: 5 parts by weight of pyromellitic dianhydride, 15 parts by weight of bisphenol A type epoxy resin (exposure equivalent 190) (relative to 100 parts by weight of resin A) Crosslinking agent C: 5 parts by weight of hexamethylenediamine (Based on 100 parts by weight of resin B) * 3: 25 parts by weight of metal powder, particle size of 200 mesh (74 μm) or less, (D / T) = 1.23 * 4: ○: Weldable, △: Partial Weldable, ×: Not weldable * 5: Fe-W-Co alloy powder manufactured by Daido Steel Co., Ltd.

In Table 2, resin A is used,
The hardness of the cold-rolled steel sheet is 4.5 or more in Mohs hardness and 90 to 162 (reference value) in Vickers hardness (Hv),
The * mark in Table 2 is as follows. * 1: Crosslinking agent A: trifunctional isocyanate (-NCO content rate 13.2%) 10 parts by weight (based on 100 parts by weight of resin A) Crosslinking agent B: 5 parts by weight of pyromellitic dianhydride, bisphenol A type epoxy Resin (epoxy equivalent 190) 15 parts by weight (based on 100 parts by weight of resin A) * 2: Metal particle blending amount (parts by weight based on 100 parts by weight of amorphous polyester) * 3: Maximum particle size D is the following mesh The following are shown. 44 μm = 325 mesh 74 μm = 200 mesh 88 μm = 170 mesh 105 μm = 140 mesh * 4: ○: Weldable, △: Partially weldable and ×: Not weldable

In Table 3, the resin C and the cross-linking agent are used.
A {trifunctional isocyanate (-NCO content 13.2
%) 10 parts by weight (based on 100 parts by weight of resin C)}
Used, the hardness of cold rolled steel sheet is more than 4.5 in Mohs hardness.
It has a Vickers hardness (Hv) of 90 to 162 (reference)
Value). In addition, * mark (* 2- * 4) in Table 3 is the above
It is the same as in the case of Table 2.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

While spot welding was not possible without the addition of metal particles (Comparative Examples 2-4), the composite type vibration damping was performed in Comparative Examples 1 and 5-12 and Examples 1-12 in which the metal powder was added. Immediately after the material was manufactured, spot welding was possible without any adverse effects such as sparks that were energized and welded even at portions other than the welded portion, and in Comparative Examples 13 and 14, some spot welding was also possible.

When no crosslinking agent is used, regardless of whether the metal particles used are harder or softer than the outer metal material, if a certain particle diameter condition and addition amount condition are satisfied, the composite vibration damping material is produced. Spot welding is possible after 10 days and 20 days (Comparative Examples 1 and 5). However, when a cross-linking agent is used, if SUS powder, which is harder than the steel plate that is the outer layer metal material, is used as the metal particles, spot welding is possible after 10 days from the production of the composite metal material, but sparks occur. However, some spot welding became impossible (Comparative Examples 6 to 12).

When the ratio D / T of the metal powder maximum particle diameter (D) to the intermediate layer resin thickness (T) is less than 1 (Comparative Examples 13 and 14), spot welding is performed immediately after the production of the composite damping material. Poor performance, spot welding became impossible after 10 days and 20 days. On the contrary, it is softer than steel plate
In Examples 1 to 12 in which the metal powder having a / T of 1 or more was used, good spot welding could be performed even in the crosslinked body even after 20 days from the production of the composite damping material. Further, the amount of metal particles blended is 1 per 100 parts by weight of the amorphous polyester mixture.
Even in parts by weight (Example 7), stable spot weldability with no change over time was obtained.

[0032]

EFFECTS OF THE INVENTION According to the present invention, the cross-linking of the intermediate resin layer for improving the characteristics of the composite type vibration damping material and the stability without time change which is equal to that of the ordinary metal material, which were impossible in the prior art. Both of the above spot weldability can be satisfied, and spot welding can be performed stably even in a system in which various properties such as adhesiveness, fluidity at high temperature, and adhesiveness are improved by crosslinking. It is extremely useful as a constituent member of automobiles, vehicles, structures, and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuo Kadowaki Inventor No. 5-10-1, Fuchinobe, Sagamihara City, Kanagawa Prefecture, Second Research Laboratory, Nippon Steel Corporation (72) Hideo Takenaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture Kamishinjo 1-4-8 (72) Inventor Masahiro Sekine 9-2 Denenchofu Minami, Ota-ku, Tokyo (72) Inventor Hiroyuki Yamamoto 6-31-102, Konandai, Konan-ku, Yokohama-shi, Kanagawa (56) References JP 61-92851 (JP, A) JP 61-98841 (JP, A) JP 58-176229 (JP, A)

Claims (2)

[Claims] 1. In a vibration damping material having a resin layer provided between two metal plates, a loss tangent (tan) based on glass transition.
The maximum value of δ) is 0.5 or more, and the cross-linked resin of the resin having the maximum value between -40 and 120 ° C is used as the intermediate layer resin, which is softer than the outer metal material and has the maximum particle size ( D)
And metal particles having a ratio (D / T) of 1 to 2 to the total thickness (T) of the intermediate layer are 1 to 10 relative to 100 parts by weight of the intermediate layer resin.
A composite damping material that can be spot welded with 0 parts by weight. 2. The composite vibration damping material capable of spot welding according to claim 1, wherein the intermediate layer resin is a crosslinked body of amorphous polyester.