JPS6374634A - Spot weldable composite type vibration-damping material - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a composite damping material that can be spot welded.
More specifically, it is a metal composite material that constitutes a component or a part of an electrical component, machine or structure, and is a vibration damping material that absorbs vibration, has conductivity, and can be spot welded. be.

[Prior Art] Today, when energy conservation is required, lightweight steel plates are required for use in car bodies and parts in order to reduce weight in the field of transporting automobiles and other vehicles. In order to promote weight reduction, it is essential to reduce the thickness of the component itself by using high-strength steel, etc., but reducing the thickness of the plate causes problems such as a decrease in tonality and other problems. , it is easy to vibrate and may cause problems such as noise.

Therefore, in order to reduce this noise, a composite type material has been proposed in which a synthetic resin intermediate layer is sandwiched between two metal layers to form a so-called three-layer structure, and the intermediate resin layer absorbs vibrations. There is.

In this case, the materials constituting the metal layer include iron, copper, aluminum, or alloys containing these ingredients, and the most commonly used materials include various steel materials and plated steel sheets. Examples include surface-treated steel sheets such as .

Although such composite vibration damping materials have excellent vibration damping performance, their value is lost if the inherent strengths of the metal material itself, such as strength, toughness, or press workability, are lost. will also be halved. Therefore, such a composite metal material must have press workability equivalent to that of a single metal material, that is, have high adhesive strength, and must also have a
It is also required that the intermediate layer resin does not flow out even when exposed to high temperatures of about 80° C., or that the adhesive strength does not drop drastically and the processed end surface does not become open.

Among the above-mentioned required characteristics, crosslinking of the intermediate layer resin is extremely effective in improving adhesive strength, adhesive strength at high temperatures, and outflow of the intermediate layer resin.

Incidentally, even if the metal composite material has an insulating resin intermediate layer, spot welding is possible by using an auxiliary electrode as seen in, for example, Japanese Utility Model Publication No. 52-55,466. In some cases, the welding process becomes complicated, making it difficult to use it online in various parts manufacturing processes. Therefore, as an attempt to make the intermediate layer of a metal composite material conductive and give it electrical spot weldability, there has been a method of filling it with a conductive filler (Japanese Unexamined Patent Publication No. 50-79
．． No. 920, JP-A-53-128.687, JP-A-5
No. 6-31,540, JP-A-57-146.649@,
JP-A-57-163.559, JP-A-57-163.
No. 560, JP-A-61-40.150, JP-A-61-
41.540), a method of sandwiching a metal net (Japanese Patent Application Laid-Open No. 58-132.550), and a method of forming irregular patterns on a metal plate (Japanese Patent Application Laid-Open No. 58-197,045M,
JP-A-59-103.748 and JP-A-59-145
, No. 142) have been proposed.

In the conventional spot-weldable composite vibration damping materials mentioned above, the method of sandwiching a metal net complicates the work during the production of damping steel plates and has an impact on press workability, and the method of adding irregular patterns to the metal plates However, the steel plate must be processed before manufacturing the damping steel plate, and there are problems such as patterns appearing on the surface of the product, the damping steel plate. In addition, filling with conductive filler is an excellent method in terms of process, but as mentioned above, when crosslinking the intermediate layer resin to improve the properties of the damping steel sheet, spot weldability deteriorates over time. .

In other words, even if spot welding is possible immediately after manufacturing vibration-damping steel plates, as time passes after manufacturing, short circuits are formed outside the welding points, causing holes in the outer metal material and sparks breaking off. As a result, there are many cases where it becomes impossible to conduct electricity and spot welding cannot be performed at all. This behavior is rarely observed if the intermediate resin layer is not cross-linked, and although it may be possible to produce composite damping materials that can be spot welded using any of the conventional techniques, It has not been possible with the prior art to produce materials whose spot weldability does not deteriorate over time when the layers are crosslinked.

[Problems to be Solved by the Invention] The present invention was devised in view of this point of view, and in order to improve the characteristics of a composite vibration damping material, even in a system in which the intermediate resin layer is cross-linked, the conventional metal plate The object of the present invention is to provide a composite vibration damping material that can be spot welded in the same way as the above method, exhibits stable spot weldability, and shows no change over time.

[Means for Solving the Problems] That is, the present invention provides a damping material in which a resin layer is provided between two metal materials, in which the resin layer is crosslinked, is softer than the outer layer metal material, and has a maximum particle size ( D> and the total thickness of the intermediate layer (T
This is a spot weldable composite vibration damping material made by blending 0.1 to 100 parts by weight of metal particles having a ratio (D/T) of 0°6 to 2 with respect to 100 parts by weight of resin.

The present invention will be explained in detail below.

First, in the present invention, the resin in the resin composition that is sandwiched between the outer layer metal material to form the resin intermediate layer and impart damping performance to the composite material is -80 to 120°C, preferably,
The maximum value of loss tangent (tan δ) at the glass transition point at -40 to 120°C is 0.5 or more, preferably 0.
A viscoelastic resin having a rating of 7 or more is preferable.

Viscoelastic resins that satisfy these conditions include polystyrene, As resin, ABS resin, MS resin, styrene resins such as impact-resistant polystyrene, polymethyl acrylate, polymethyl methacrylate, polyethyl methacrylate, and acrylic resins. Acrylic resins such as copolymers, polyvinyl chloride, vinyl chloride/vinyl acetate copolymers, vinyl chloride resins such as vinyl chloride/acrylic acid ester copolymers, acetic acid such as polyvinyl acetate, polyvinyl formal, polyvinyl butyral, etc. Vinyl resin, ethylene/α-olefin copolymer, ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ethylene/methacrylic acid ester copolymer, metal crosslinked product of ethylene/methacrylic acid copolymer, etc. ethylene resins, propylene resins such as propylene/ethylene copolymers, propylene/butene copolymers, amorphous polyamides such as copolymerized nylon,
Examples include various thermoplastic resins such as amorphous polyester. In addition, styrene-butadiene rubber, natural rubber, butadiene rubber, chloroprene rubber, butyl rubber,
Elastomers such as nitrile rubber, acrylic rubber, ethylene-acrylic rubber, and EPDM, and thermosetting resins such as epoxy resins, phenolic resins, and unsaturated polyester resins can also be used. These resins can be used alone or in combination of two or more. Further, these resins are appropriately selected from the viewpoint of the performance required of the composite vibration damping material, such as vibration damping properties, heat resistance, workability, oil resistance, and cold resistance.

The above-mentioned intermediate layer resin composition is used as an intermediate layer of the composite vibration damping material to prevent it from flowing out even when exposed to high temperatures such as in a baking painting line, and also to provide excellent adhesion, especially in presses. This intermediate layer must be crosslinked in order to improve the shear adhesive strength, which has an important effect on processability. The crosslinking agent used for this purpose can be selected as appropriate depending on the functional group of the intermediate layer resin, but examples include resin vulcanizing agents such as sulfur, organic sulfur compounds, alkylphenol/formaldehyde resins, and heat-reactive phenolic resins. , polyamines, polyols, organic peroxides, amine resins, isocyanates, epoxies, polyamide amines, acid anhydrides, etc., and optional crosslinking accelerators, activators, crosslinking retarders, etc. It can also be used in combination with Further, when a mixture of two or more types of polymeric substances is used as the intermediate layer resin, it is not necessarily necessary that the previous component be crosslinked, but it is sufficient that at least one component is crosslinked.

Furthermore, among the resin crosslinked materials mentioned above, resin crosslinked materials are preferred from the viewpoint of the performance required for composite vibration damping materials, such as vibration damping properties, heat resistance, workability, adhesion with metal materials, and oil resistance. One component of the loss tangent (tan δ
) is preferably a crosslinked amorphous polyester having a maximum value of 0.5 or more and a temperature at which this maximum value is between 140 and 120°C.

Such amorphous polyesters can be obtained by dissolving crystalline saturated polyesters such as polyethylene terephthalate and polybutylene terephthalate in ethylene glycol at high temperature, and then dissolving saturated polyesters in triethylene glycol, 1,4-butanediol, neopentyl glycol, etc. It can be synthesized by adding an alcohol and performing a transesterification reaction, or it can also be synthesized by copolymerizing a saturated polyhydric carboxylic acid and a saturated polyhydric alcohol. The latter saturated polycarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and trimellitic anhydride. etc. are exemplified. In addition, examples of saturated polyhydric alcohols include ethylene glycol, 1,4-butanediol, 1,
5-bentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polyethylene glycol, neopentyl glycol, propylene glycol, 1,4-cyclohexane dimetatool,
Examples include pentaerythritol and trimethylolpropane. There are many combinations of these monomers, which are appropriately selected depending on the desired melting point, glass transition temperature, degree of unquality, etc. Further, these amorphous polyesters can be used alone or in combination of two or more.

The crosslinking agent for crosslinking this 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, compounds such as amine, isocyanate, and epoxy are exemplified. When the terminal functional group of polyester is a hydroxyl group, examples include compounds such as amines, isocyanates, acid anhydrides, epoxy, chlorine, and silane coupling agents, as well as organic peroxides that are effective for three-dimensional crosslinking. A radical generator may also be used.

Next, the metal particles that are blended into the intermediate layer resin to constitute the resin composition need to be softer than the outer layer metal material, and differ depending on the type of the outer layer metal material. If the metal particles are harder than the outer layer metal material, even if the particle size satisfies the following conditions, spot weldability will become unstable if the intermediate layer resin is crosslinked. Examples of metal particles that are softer than the outer layer metal material include:
When the outer layer metal material is a cold-rolled steel sheet, examples of the conductive particles include metal particles of copper, nickel, aluminum, lead, zinc, etc., which are softer than the steel sheet, and alloys of these metals. These metal particles can be used alone or
Two or more types can also be used in combination.

These metal particles must have a ratio (D/T) between the maximum particle size (D> and the total thickness (T>) of the intermediate resin) of 0.6 to 2. This refers to the opening size of the sieve when the particles are sieved.The opening of this sieve is selected to be smaller than the maximum particle size of the metal particles before sieving, and the particle size distribution of the metal particles is Normally, the distribution is lognormal, and there are some particles with a particle size near the sieve opening.If D/T is less than 0.6, stable spot weldability cannot be obtained, and if it exceeds 2, The adhesive strength between the metal material and the resin layer decreases.

In this way, the value of D/H is determined by the balance between spot weldability and adhesiveness, and it is more preferable for D/T to be 0 in order to ensure stable spot weldability and not reduce adhesive strength. .8 to 2, more preferably 1.
It is 0 to 1.5.

The amount of these conductive particles to be blended is 0.1 to 100 parts by weight per 100 parts by weight of the resin, preferably 0.1 to 50 parts by weight, more preferably 0.1 to 10 parts by weight. be. If the amount is less than 0.1 parts 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 will decrease. Further, if the metal particles are classified under conditions such that most of the particles have a particle size near the maximum particle size, stable spot weldability can be ensured even when the amount of metal particles is about 0.5 parts by weight per 100 parts by weight of the resin.

Roughly speaking, the intermediate resin layer of the spot-weldable damping steel sheet 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 a maximum particle diameter (D) and a total thickness of the resin multilayer (T ＞
It is only necessary to mix a material whose relationship satisfies the above conditions only in the center layer of the multilayer body.

The method for producing the composite damping material of the present invention is not particularly limited. For example, a method for bonding a metal layer and a resin layer is to sandwich a resin composition between two metal layers, Examples include a method of heat-pressing at a temperature equal to or higher than the melting point of the composition, or a method of applying a solution of the resin composition to two metal layers, drying them to remove the solvent, and then bonding them together.

[Function] According to the present invention, by blending metal particles that are softer than the outer layer metal material in the intermediate resin layer in the composite vibration damping material, the metal particles are plastically deformed when they come into contact with the outer layer metal material, and the upper and lower outer layers It is possible to electrically short-circuit the metal materials and provide stable spot weldability that does not change over time, even if the composite vibration damping material has a crosslinked intermediate resin layer.

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

In both Examples and Comparative Examples, the viscoelastic resin composition has a maximum value of loss tangent (tan δ) based on glass transition measured in 110) 1z shear mode using a dynamic viscoelasticity measuring device of 1.31.
The temperature at which this maximum occurs is 11.1°C, and the molecular weight is 15,00.
0 to 20,000 amorphous polyester, the loss tangent (tan δ) is 1.39 and the maximum temperature is 37.7 ° C.
, a 2:1 mixture with an amorphous polyester having a molecular weight of 15° OOO to 20,000 (hereinafter referred to as resin A), and a loss tangent (tan δ) based on glass transition of 1.50 and a temperature at which this maximum occurs at 20 ℃ glycidyl methacrylate/methyl acrylate/ethyl acrylate copolymer (hereinafter referred to as resin B) was used. A crosslinking agent was added as needed to prepare a resin composition. The crosslinking agents used at this time were 10 parts by weight of a trifunctional isocyanate with an isocyanate group content of 13.2% (hereinafter referred to as crosslinking agent A) and 5 parts by weight of pyromellitic anhydride. 5 parts by weight of hexamethylene diamine (hereinafter referred to as crosslinking agent C) per 15 parts by weight of a bisphenol A type epoxy resin (hereinafter referred to as crosslinking agent B) with an epoxy equivalent of 190 and 100 parts by weight of acrylic acid ester copolymer resin B). Added.

Regarding metal particles, the types shown in Tables 1 and 2 were sieved through meshes, classified to have a maximum particle size or less, and added in a predetermined amount.

The above composition was applied to a cold rolled steel plate 2 with a thickness of 0.8171#I.
After applying it to one sheet, dry it, and then paste the two sheets together to give a 180
℃, 5 Kg/crA for 5 minutes, followed by cooling pressing to produce a composite vibration damping material.

Tables 1 and 2 show the results of a spot welding test performed on the composite restraint material obtained by the above method and a cold rolled steel plate with a thickness of 0°8M. The spot welding test was conducted at a pressure of 250 KI.
The test was carried out under the conditions of a current of 6.4 kA and a duration of 14 cycles.

In addition, in Table 1, the thickness T> of the intermediate resin layer is 60
μTrLT, and the hardness of the cold-rolled steel sheet is 4.0 on the Mohs scale.
5 or higher and Vickers hardness (Hv) is 90-162
(Literature value), and the * marks in Table 1 are as follows.

*1: Resin A: Amorphous polyester resin Conia acrylic ester copolymer 2: Crosslinking agent A: Functional isocyanate (-NGO content 13.2%) 10 parts by weight (relative to 100 parts by weight of resin A) Crosslinking agent B: 5 parts by weight of non-hopyromellitic acid, 15 parts by weight of bisphenol A type epoxy resin (epoxy equivalent: 190) (relative to 100 parts by weight of resin A) Crosslinking agent C: 5 parts by weight of hekyrimethylenediamine (resin 81
00 parts by weight) *3: 25 parts by weight without metal powder, particle size 200 mesh (74 μR) or less, (D/T>=1
．． 23 *4: O: Weldable, △ Partially weldable, X: Not weldable *5: Fe-W-Co alloy powder manufactured by Daido Steel
In the table, resin A is used, and the hardness of the cold-rolled steel sheet is 4.5 or more on the Mohs hardness and 90 to 162 (literature value) on the Vickers hardness (Hv), and the * mark in Table 2 is as follows. It is as follows.

*1: Crosslinking agent A: Functional isocyanate (-NGO content 13.2%) 10 parts by weight (relative to 100 parts by weight of resin A) Crosslinking agent B: Anhydrous pyromellit@5 parts by weight, bisphenol A type epoxy resin ( Epoxy equivalent 190) 15 parts by weight (per 100 parts by weight of resin A) *2: Amount of metal particles blended (overlapping parts per 100 parts by weight of amorphous polyester) *3: Maximum particle size is less than or equal to the following mesh size: Show things.

44μm = 325 meshure 4μ71? , = 200 mesh aa μm = 17o mesh 105 μm = 140 mesh *4: O: Weldable, △ Partially weldable, and ×: Unweldable Spot welding is impossible with no metal particles added (Comparative Examples 2 to 4). On the other hand, in Comparative Examples 1 and 5 to 12 and Examples 1 to 14, in which metal powder was added, composite vibration damping materials were used! l
! Immediately after construction, spot welding is possible without any negative effects such as sparks caused by applying electricity to areas other than the welded area.
In addition, spot welding was partially possible in Comparative Examples 13 and 14 as well.

If a crosslinking agent is not used, regardless of whether the metal particles used are harder or softer than the exterior metal material, if certain particle size conditions and addition amount conditions are satisfied, 10 days after manufacturing the composite vibration damping material, Spot welding is possible even after 20 days (Comparative Examples 1 and 5).

However, if a cross-linking agent is used, and if SUS powder, etc., which is harder than the horizontal plate covered with the outer layer metal material, is used as the metal particles, spot welding is possible after 10 days after manufacturing the composite metal material, but sparks will occur. Spot welding became impossible in some cases (Comparative Examples 6 to 12).

In addition, when the metal powder maximum particle diameter (D> is the intermediate layer resin thickness (T>) and the ratio D/T is less than 0.6, Comparative Examples 13 and 14)
Even immediately after manufacturing the composite damping material, spot weldability was poor, and spot welding became impossible after 10 and 20 days. On the other hand, it is softer than steel plate and D/T is 0.
．． In Examples 1 to 14 in which metal powders of 6 or more were used, good spot welding could be performed in the crosslinked bodies even 20 days after the production of the composite vibration damping material.

Furthermore, stable spot weldability with no change over time was obtained even when the amount of metal particles was 1 part by weight per 100 parts by weight of the amorphous polyester mixture (Example 7).

[Effects of the Invention] According to the present invention, the intermediate resin layer can be cross-linked to improve the properties of the composite vibration damping material, which was not possible with the prior art, and it can be stabilized without aging equivalent to ordinary metal materials. It is possible to stably perform spot welding even in systems with improved properties such as adhesiveness, flow resistance at high temperatures, and adhesion through crosslinking. It is extremely useful as a component of automobiles, vehicles, structures, etc.

Claims (2)

[Claims] (1) In a vibration damping material in which a resin layer is provided between two metal plates, the resin layer is cross-linked and is softer than the outer layer metal material, and the maximum particle size (D) and the total thickness of the intermediate layer (T) are Ratio (D
A spot weldable composite vibration damping material comprising 0.1 to 100 parts by weight of metal particles having a /T) of 0.6 to 2 per 100 parts by weight of a resin. (2) Loss tangent (tan δ) of resin based on glass transition
The maximum value of is 0.5 or more, and the temperature that shows this maximum value is 40
The spot-weldable composite damping material according to claim 1, which is a crosslinked body of amorphous polyester at a temperature between 120°C and 120°C.