JPH082611B2 - Composite metal plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composite metal plate having excellent vibration damping properties.

[Conventional technology and problems]

In recent years, noise prevention of automobiles and OA equipment is becoming a big problem. As a measure to prevent noise, there are two methods of reducing the vibration of the part that is the sound source or not outputting the generated vibration to the outside, but composite metal plate has been attracting attention as a material for that in the past. There is. For example,
39-12451, Japanese Patent Publication No. 54-18700 and the like disclose a composite metal plate in which two metal plates are bonded together with a synthetic resin as an intermediate layer. In such a conventional composite metal plate,
Nylon, polyethylene, polypropylene, etc. are used as the resin, but the damping characteristics are not always sufficient.
Further, in the case of polypropylene, there is a problem that the performance is remarkably deteriorated depending on the temperature history because the damping property is provided by selecting a special molding condition in the intermediate region between amorphous and crystalline. Also, generally the softening temperature,
Since the resin with a low melting point is used, the operating temperature of the composite metal plate is limited, and the expansion coefficient of the resin used is significantly different from that of the metal, so there is a concern that the metal plate may peel off when used at high temperatures. Yes, I was not satisfied with it.

[Means for solving problems]

In view of the above-mentioned problems, the present inventors have earnestly studied about the resin used for the intermediate layer of the composite metal plate, and as a result, have newly developed a melt-processable polyester capable of forming an anisotropic melt phase (hereinafter The present invention has been completed by discovering that "liquid crystalline polyester") is excellent in vibration damping properties and various physical properties such as heat resistance and is extremely suitable as a member used for a composite metal plate.

That is, the present invention is a composite metal plate having excellent vibration damping properties, characterized in that a layer made of melt-processable polyester capable of forming an anisotropic melt phase is provided between metal plates.

The liquid crystalline polyester used in the present invention will be specifically described below.

The liquid crystalline polyester used in the present invention is a melt-processable polyester and has a property that the polymer molecular chains take a regular parallel arrangement in a molten state. The state in which molecules are arranged in this manner is often referred to as a liquid crystal state or a nematic phase of a liquid crystal substance. Such polymer molecules are generally elongated, flat, and fairly stiff along the long axis of the molecule,
It usually consists of a polymer having a chain extension bond with a coefficient that is either coaxial or parallel.

The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using a perpendicular polarizer. More specifically, the anisotropic molten phase can be confirmed by using a Leitz polarization microscope and observing the molten sample placed on the Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. The polymer is optically anisotropic. That is, it transmits light when inspected between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even if it is stationary.

As the constituent components of the polymer forming the anisotropic molten phase as described above, one composed of one or more of aromatic dicarboxylic acid and alicyclic dicarboxylic acid One of aromatic diol, alicyclic diol and aliphatic diol One or more aromatic hydroxy carboxylic acids one or more aromatic thiol carboxylic acids one or more aromatic dithiols, aromatic thiol phenols
One or more, selected from aromatic hydroxyamine, one or more of aromatic diamine, etc., and the polymer forming the anisotropic molten phase consists only of polyester II) consisting of I) Polyester III) consisting of polyester IV) and polythiol ester consisting only of V) Polythiol ester consisting of V) VI) and polythiol ester VII) consisting of polyesteramide VIII) and a combination of polyesteramide consisting of Is a polyester that forms an anisotropic melt phase composed of

Further, although not included in the category of the combination of the above components, the polymer forming the anisotropic molten phase includes aromatic polyazomethine, and specific examples of such a polymer include:
Poly (nitrilo-2-methyl-1,4-phenylene nitriloethylidyne-1,4-phenyleneethylidine); poly (nitrilo-2-methyl-1,4-phenylene nitrilomethylidyne-1,4-phenylenemethylidine ); And poly (nitrilo-2-chloro-1,4-phenylene nitrilomethylidine-1,4-phenylenemethylidine).

Further, although not included in the category of the combination of the above components, polyester carbonate is included as the polymer forming the anisotropic molten phase. It consists essentially of 4-oxybenzoyl units, dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The polyesters of the above I), II) and III) and the polyesteramides of VIII), which are polymers forming an anisotropic molten phase suitable for use in the present invention, have a functional group capable of forming a required repeating unit by condensation. It can be produced by various ester forming methods capable of reacting the organic monomer compounds with each other. For example, the functional groups of these organic monomer compounds are carboxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides,
Amine group is good. The organic monomer compound can be reacted by a molten acidolysis method without the presence of a heat exchange fluid. In this method, the monomers are first heated together to form a molten solution of the reactants. As the reaction is continued, solid polymer particles are suspended in the liquid. Vacuum may be applied to facilitate removal of volatiles (eg acetic acid or water) by-produced in the final stage of the condensation.

Also, a slurry polymerization method can be employed for forming a liquid crystalline polyester suitable for use in the present invention. in this way,
The solid product is obtained in suspension in the heat exchange medium.

Regardless of which of the above-mentioned melt-acidification method and slurry polymerization method is employed, the organic monomer reactant that induces the liquid crystalline polyester is in a modified form in which the hydroxyl group of such a monomer is esterified (that is, as a lower acyl ester). It can be subjected to a reaction. Further, the lower acyl group preferably has about 2 to 4 carbon atoms. Preferably, the acetic acid ester of such an organic monomer reactant is subjected to the reaction.

Further, as typical examples of the catalyst which can be optionally used in either the molten acidolysis method or the slurry method, dialkyl tin oxide (eg, dibutyl tin oxide), diaryl tin oxide, titanium dioxide, antimony trioxide, alkoxy titanium silicate, titanium alkoxide. , Alkali and alkaline earth metal salts of carboxylic acids (eg zinc acetate), Lewis acids (eg BF ₃ ), hydrogen halides (eg HC
l) and other gaseous acid catalysts. The amount of catalyst used is generally about 0.001 to 1 based on the total weight of monomers.
% By weight, especially about 0.01 to 0.2% by weight.

Liquid crystalline polymers suitable for use in the present invention tend to be substantially insoluble in common solvents and therefore unsuitable for solution processing. But as already mentioned,
These polymers can be easily processed by conventional melt processing methods. Particularly preferred liquid crystalline polymers are somewhat soluble in pentafluorophenol.

Liquid crystalline polyesters suitable for use in the present invention generally have a weight average molecular weight of about 2,000 to 200,000, preferably about 1
It is from 0,000 to 50,000, particularly preferably from about 20,000 to 25,000. On the other hand, suitable wholly aromatic polyesteramides generally have a molecular weight of about 5,000 to 50,000, preferably about 10,000 to 30,
000, for example, 15,000 to 17,000. The measurement of such a molecular weight can be carried out by a standard measurement method which does not involve solution formation of gel permeation chromatography and other polymers, for example, by quantifying an end group by infrared spectroscopy on a compression molded film. The molecular weight can also be measured by using a pentafluorophenol solution and using a light scattering method.

The above liquid phase polyesters and polyester amides also contain 0.1% by weight of pentafluorophenol at 60 ° C.
It typically exhibits an inherent viscosity (IV) of at least about 2.0 dl / g, for example about 2.0 to 10.0 dl / g when dissolved at a concentration.

The polymer exhibiting the anisotropic melt phase used in the present invention is
Aromatic polyesters and aromatic polyesteramides are preferable, and aromatic polyesters and polyesters partially containing aromatic polyesteramides in the same molecular chain are also preferable examples.

Preferred examples of compounds constituting them are 2,6-naphthalenedicarboxylic acid, 2,6-dihydroxynaphthalene,
1,4-dihydroxynaphthalene and 6-hydroxy-2
-Naphthalene compounds such as naphthoic acid, biphenyl compounds such as 4,4'-diphenyldicarboxylic acid and 4,4'-dihydroxybiphenyl, the following general formulas (I), (II) or (II)
Compound represented by I): (However, X: alkylene (C _{1 to} C ₄ ), alkylidene, -O
A group selected from —, —SO—, —SO ₂ —, —S—, and —CO— Y: — (CH ₂ ) _n — (n = 1 to 4), —O (CH ₂ ) _n O— (n = A group selected from 1 to 4)) p-hydroxybenzoic acid, terephthalic acid, hydroquinone, p-aminophenol, p-phenylenediamine and other para-substituted benzene compounds and their nucleus-substituted benzene compounds (substituents are chlorine). , Bromine, methyl, phenyl, 1-phenylethyl), isophthalic acid, resorcin, and other meta-substituted benzene compounds.

Further, the liquid crystalline polyester used in the present invention may be a polyalkylene terephthalate which does not partially show an anisotropic melt phase in the same molecular chain, in addition to the above-mentioned constituents. In this case, the alkyl group has 2 to 4 carbon atoms.

Among the above-mentioned components, those containing one or more compounds selected from a naphthalene compound, a biphenyl compound and a para-substituted benzene compound as essential components are more preferable examples. Of the p-position-substituted benzene compounds, p-hydroxybenzoic acid, methylhydroquinone and 1-phenylethylhydroquinone are particularly preferable examples.

Particularly preferred polyesters that form an anisotropic melt phase for use in the present invention include repeating units containing a naphthalene moiety such as 6-hydroxy-2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene. About 10
It is contained in an amount of not less than mol%. Preferred polyesteramides are those containing repeating units of the above-mentioned naphthalene moieties and moieties consisting of 4-aminophenol or 1,4-phenylenediamine.

Specific examples of the compounds constituting the above-mentioned I) to VIII) and polyesters forming an anisotropic melt phase which are preferable for use in the present invention are described in JP-A-61-69.
It is described in Japanese Patent No. 866.

Liquid crystalline polyester has the highest strength in plastics that can be molded under normal conditions using a normal molding machine,
It has rigidity, and its vibration damping property is large.

Since the liquid crystalline polyester used in the present invention has extremely high strength as described above and excellent vibration damping property,
A two-layer composite metal plate obtained by laminating this film on a metal plate, or a composite metal plate having a laminated structure in which a layer of liquid crystalline polyester is provided between two metal plates should have excellent damping characteristics. Become.

In order to produce the two-layer composite metal plate of the present invention, (1) a method of heating and pressurizing a separately prepared liquid crystalline polyester film or sheet to the metal plate, in this case, for example, an epoxy adhesive, You may adhere | attach via a urethane type adhesive agent.

(2) A method of laminating a film or sheet of liquid crystalline polyester immediately after being extruded from an extruder on a metal plate.

Etc.

Further, in order to produce a sandwich type laminated composite metal plate, (3) a method in which a separately prepared liquid crystal polyester film or sheet is sandwiched between two metal plates and bonded by heating and pressing.

(4) A method in which a film or sheet of liquid crystalline polyester immediately after being extruded from an extruder is bonded onto a metal plate, and then another metal plate is bonded to the liquid crystalline polyester side.

(5) A method in which liquid crystalline polyester is melted on a metal plate and another metal plate is heated and pressed.

Etc.

The type of metal plate used for the composite metal plate of the present invention is not particularly limited, and the two metal plates do not have to be of the same kind, and different kinds of metal plates may be used. Examples of the metal plate include various steel plates, aluminum plates, copper plates, brass plates and the like.

The liquid crystalline polyester may further contain various inorganic / organic fillers depending on the purpose. For example, substances added to general thermoplastic resins and thermosetting resins,
That is, glass fibers, carbon fibers, metal fibers, ceramic fibers, boron fibers, potassium titanate fibers, general inorganic fibers such as asbestos, wholly aromatic polyamide fibers, aromatic liquid crystalline polyester fibers, synthetic phenolic fibers, etc. Resin fiber, calcium carbonate, highly dispersible silicate, alumina, aluminum hydroxide, talc, clay, mica, glass flakes, glass powder, glass beads, quartz sand, silica sand, wollastonite, various metal powders, carbon black , Powdery substances such as barium sulfate and calcined gypsum, and powdered particles such as silicon carbide, alumina, boron nitrite and silicon nitride, plate-like inorganic compounds, whiskers and metal whiskers and the like.

These inorganic / organic fillers can be used alone or in combination of two or more.

When a filler is added, it is possible and desirable to use a commonly used known surface treatment agent or sizing agent in order to enhance the adhesiveness to the liquid crystalline polyester.

Examples are functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, titanate compounds and the like.

These compounds may be used after being subjected to a surface treatment or a converging treatment in advance, or may be added at the same time when the materials are adjusted.

Further, the liquid crystalline polyester of the present invention may be a polymer blended with another thermoplastic resin within a range that does not impair the intended purpose of the present invention.

The thermoplastic resin used in this case is not particularly limited, but examples thereof include polyolefins such as polyethylene and polypropylene, aromatic dicarboxylic acids such as polyethylene terephthalate and polybutylene terephthalate, and aromatic polyesters comprising diols or oxycarboxylic acids. , Polyacetal, (homo or copolymer), polystyrene, polyvinyl chloride, polyamide, polycarbonate, ABS, polyphenylene oxide, polyphenylene sulfide, fluororesin and the like. Also,
Two or more kinds of these thermoplastic resins can be mixed and used. In addition, these resins include mechanical, electrical,
In order to improve various properties such as chemical properties and flame retardancy, various additives and reinforcing agents can be added as necessary.

〔The invention's effect〕

As is clear from the above description, the composite metal plate of the present invention is
A layer of liquid crystalline polyester laminated on one metal plate, more preferably a layer of liquid crystalline polyester laminated between two metal plates, which has extremely good vibration damping property as shown in Examples. . A particular feature is that the vibration damping property does not change with temperature.

A molded product of liquid crystalline polyester alone has a good vibration damping property, but the product of the present invention is effective when used for vibration damping and shock damping of an article for which strength is particularly required.

The liquid crystalline polyester used in the present invention has a melting point of 280.
The composite metal plate of the present invention withstands use at a considerably high temperature and can be used in the vicinity of an automobile engine because the composite metal plate of the present invention has a high temperature in the vicinity of 0 ° C and does not deteriorate even at high temperatures. Further, since the coefficient of expansion due to temperature is close to that of metal, there is an advantage that peeling or adhesion between the metal and the liquid crystalline polyester due to difference in expansion is extremely small.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these combinations.

Examples 1 to 5 and Comparative Example 1 A composite metal plate prepared by forming a film having a thickness of 50 μm from liquid crystal polyester resins A, B, C, D and E described later and bonding the steel plates having a thickness of 2 mm with an epoxy adhesive. It was created.

The relationship between the temperature and the loss coefficient of each sample was investigated by the forced vibration method based on the mechanical impedance method (central vibration). The measurement was performed at a frequency of 500 Hz and a temperature of 40 to 150 ° C.

 The results are shown in FIG.

For comparison, FIG. 1 also shows the results of a commercial product using polypropylene as a resin.

The liquid crystalline polyesters A to E used in the examples have the following constitutional units.

[Brief description of drawings]

FIG. 1 is a graph showing the performance test results of the composite metal plate.

Claims (1)

[Claims] 1. A composite metal plate having excellent vibration damping properties, characterized in that a layer made of melt-processable polyester capable of forming an anisotropic melt phase is provided between metal plates.