JPH05111978A - Production of composite damping material - Google Patents

Abstract

PURPOSE:To produce a composite damping material having good damping capacity within a wide temp. range by holding a crosslinked resin obtained by reacting a prepolymer with a low mol.wt. compound having a functional group forming a covalent bond upon the reaction with the functional group of the prepolymer between two metals. CONSTITUTION:A composite damping material is produced by holding a crosslinked resin obtained by reacting a prepolymer (e.g. unsaturated polyester) and a low mol.wt. compound (e.g. isocyanate compound) having a functional group forming a covalent bond upon the reaction with the functional group of the prepolymer between two metals. The composite damping material has good damping capacity and shows excellent bonding strength between the resin and the metals at low temp. and high temp. and, when the resin is compounded with a conductive filler, (e.g. copper powder), the composite damping material is also excellent in spot weldability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a method for manufacturing a composite damping material.

[0002]

2. Description of the Related Art Among materials having a vibration damping effect, a composite vibration damping material in which a resin is interposed between two metal plates has attracted attention as a noise and vibration preventing material.

In this composite damping material, the intermediate resin layer converts the vibration applied to the metal plate into heat energy, and it is used for building materials such as engine oil pans, stairs, doors, floor materials, roof materials, motors, etc. It is being used in applications such as compressor covers, or is being studied for use. The characteristic required of such a composite damping material is that it has a damping function in a wide temperature range.

Generally, when an object is vibrated, the amplitude increases at a certain frequency (fr). This frequency is called the resonance frequency. Assuming that the amplitude at the resonance frequency is A ₀ , the half of this energy is that the amplitude is A ₀ / √2 (dB
The displayed frequency is -3 dB). If this frequency width (half-value width, 3 dB value width) is Δf, the loss coefficient η is expressed by the following equation. η = Δf / fr The damping function can be evaluated by such a loss coefficient η.

Further, it is desired that the adhesive property between the resin layer and the metal plate is high. Specifically, it has excellent adhesive strength at room temperature that can withstand the shearing force applied to the damping material during press working,
It is required that the adhesive strength be maintained even after the coating treatment at a high temperature of up to 200 ° C. and that the adhesive strength in the temperature range during use be high. Further, if the composite vibration damping material can be spot-welded, its application is further expanded.

As the resin for the intermediate layer, conventionally, polyurethane, polyester, polyamide, polyisobutylene,
Ethylene / α-olefin copolymers, ethylene-vinyl acetate copolymer resins, crosslinked polyolefins, polyvinyl acetals and the like have been investigated. Other, asphalt,
Synthetic rubber, acrylic adhesives, epoxy resins, etc. are also being considered.

The composite damping material using these polymer substances in the intermediate layer does not reach the level at which both the damping performance and the adhesive performance are sufficiently satisfied. For example, JP-A-63-48321
In the specification, the aromatic dicarboxylic acid component is 60%
Polyester diol having a molecular weight of 600 to 6000, which comprises the dicarboxylic acid component and glycol component contained above, and a molecular weight of 6 comprising a fatty acid dicarboxylic acid and a fatty acid glycol.
Disclosed is a resin for a vibration damping material obtained by reacting a diisocyanate compound with a mixture containing a polyester diol in a specific ratio of 0 to 6000. The vibration damping material having the resin as an intermediate layer has a vibration damping performance, an adhesive performance and a press molding. It is described that it has excellent properties. However, it is necessary to improve the adhesiveness at a high temperature for use in a high temperature atmosphere, and it is desired to improve the damping performance in a wider temperature range.

Although the above specification describes that a small amount of 2,4,4'-triisocyanate diphenyl and benzene triisocyanate can be used together with the diisocyanate component, it is used for any purpose and to what extent. There is no mention of that. Moreover, there is nothing to touch regarding spot weldability.

In JP-A-64-48813, a weight average molecular weight of 5,000 or more and a softening point of 50 to 150 ° C.
The resin for a vibration-damping steel sheet obtained by reacting the saturated copolyester and the isocyanate compound having at least two isocyanate groups is described. It is described that the vibration-damping steel sheet having this resin as an intermediate layer has excellent vibration-damping performance in the temperature range of 0 to 50 ° C., and has excellent adhesive performance required at the time of press molding and excellent adhesive stability at high temperatures. The excellent property was also confirmed by the additional test by the inventor. However, there is a demand for improvement so that the vibration damping performance is exhibited in an even wider temperature range.

The above specification does not mention spot welding performance.

[0011]

Thus, the first object of the present invention is to have a vibration damping performance in a wide temperature range and to have an adhesive strength at room temperature which can withstand the shearing force applied during press working. It is an object of the present invention to provide a method for producing a composite vibration damping material, which substantially retains the adhesive strength even after a coating treatment at a high temperature and has a high adhesive strength in the operating temperature range.

A second object of the present invention is to provide a method for producing a composite vibration damping material which is excellent in spot weldability in accordance with the above excellent properties.

[0013]

The first object of the present invention is achieved by the following three general aspects. According to the first aspect of the present invention, a prepolymer having an average of at least two functional groups (X) per molecular chain and a functional group capable of reacting with the functional groups (X) to form a covalent bond. (Y)
A low molecular weight compound (A) having at least two per molecule and a functional group (Y ') capable of reacting with the functional group (X) to form a covalent bond, the number of the low molecular weight compound (A) being one per molecule. A low molecular weight compound (B), which is more than A),
Under the condition that the low molecular weight compound (A) is present in an amount of 15 to 85% by weight of the total amount of the low molecular weight compound (A) and the low molecular weight compound (B), the resin obtained by the reaction is sandwiched between two metal plates. A method for manufacturing a composite vibration damping material in which a resin layer is sandwiched between two metal plates is provided.

According to the second aspect of the present invention, the prepolymer (C) having at least two functional groups (X) on average per one molecular chain and the number of functional groups (X ') contained per one molecular chain. Is more prepolymer (D) than prepolymer (C)
And a low molecular weight compound having an average of at least two functional groups (Y) capable of reacting with the functional groups (X) and the functional groups (X ′) to form a covalent bond per molecule, the prepolymer (C ) Is prepolymer (C) and prepolymer (D)
The resin layer is sandwiched between two metal plates, characterized in that the resin obtained by the reaction is operated so as to be sandwiched between the two metal plates under the condition that 10 to 90% by weight of the total amount of A method for manufacturing the composite vibration damping material is provided.

According to the third aspect of the present invention, a prepolymer having at least two functional groups (X) on average per molecular chain is reacted with the functional groups (X) to form a covalent bond. The number of functional groups (Y) that can be formed is at least 2 per molecule.
And a low molecular weight compound having a number of two are mixed, the mixture is applied to at least one surface of two metal plates, and a functional group (X capable of reacting with the functional group (Y) to form a covalent bond on the applied surface. ′) Is sprayed with an average of at least two prepolymers per molecular chain, and then pressure-bonded so that the coated surface is sandwiched between two metal plates. A resin layer is sandwiched between two metal plates. A method for manufacturing the composite vibration damping material is provided.

The second object of the present invention is to provide the above-mentioned first to first items.
In each of the third aspects, it is achieved by blending a conductive substance with a resin.

The following description of the present invention in detail will make apparent more preferred aspects of the invention and the advantages associated therewith.

[0018] a metal plate can be used in the production of the vibration damping material of the first aspect the metal plate of the Invention The present invention is not particularly limited, cold-rolled steel plate or chromate-treated steel sheets, zinc-plated steel sheet, phosphorus It may be a surface-treated steel plate such as an acid-treated steel plate, or a copper plate, an aluminum plate, a stainless plate, a titanium plate, or the like. Further, the shape may be either a coil shape or a cut plate. The thickness of the metal plate is not particularly limited, but is usually 0.2 in consideration of molding processability and shape retention.
Those having a thickness of about 2 mm are preferably used.

Prepolymer In this embodiment, a prepolymer having at least two functional groups (X) per one molecular chain is used as one of the raw materials used for preparing the resin for the intermediate layer. The number average molecular weight of this prepolymer is preferably 7,000 to 50,000, and particularly preferably 10,000 to 30,000, in consideration of vibration damping performance and workability during coating on a metal plate. As the functional group (X), a hydroxyl group, an epoxy group, an amino group, a carboxyl group, an isocyanate group, an acid anhydride group and the like can be preferably mentioned.

Specific examples of the prepolymer include a polyester having a hydroxyl group or a carboxyl group, a glycidyl ether of a polyol, a glycidyl ester of a polyester having a carboxyl group, a polyamide having an amino group or a carboxyl group, a hydroxyl group, a carboxyl group or an acid anhydride group. Examples thereof include modified polyolefins and the like.

The average number of such functional groups (X) is 2 or more, preferably 2 to 4 per one molecular chain of the prepolymer. Here, the number of functional groups (X) per one molecular chain is a value as an average value. Such prepolymers are known per se and commercially available, and can be extremely easily produced by a person skilled in the art by a known method.

Among the prepolymers, the case of polyester will be described in detail. Aromatic dibasic acids such as terephthalic acid, isophthalic acid, and phthalic acid, succinic acid, glutaric acid, adipic acid, β-methyladipic acid, pimelic acid, and 1,6-hexanedicarboxylic acid as carboxylic acid components constituting polyester. , Aliphatic dibasic acids such as azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, and hexadecanedicarboxylic acid; unsaturated fatty acids such as maleic acid and dimer acid; and aromatic polybasic acids such as trimellitic acid. It can be illustrated. Further, as alcohol components, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol. , 3-methylpentanediol, 1,3-hexanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, hydrogenated bisphenol A, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, Examples thereof include glycols such as polypropylene glycol and polytetramethylene glycol, and polyfunctional alcohols such as trimethylolpropane and pentaerythritol.

Of course, in synthesizing polyester,
According to the common knowledge of those skilled in the art, these carboxylic acids and alcohols can be directly reacted to form an ester, or the carboxylic acid can be converted to an ester or an acid halide and reacted with an alcohol.

The preferred prepolymer is a saturated polyester, but especially the acid component has a terephthalic acid component of 30 to 30%.
A saturated polyester having 90 mol% and the remainder being fatty acid dibasic acid, particularly adipic acid or sebacic acid is preferable. A polyester in which ethylene glycol accounts for 30 to 80 mol% as a glycol component and the remaining component is a glycol having 6 carbon atoms or a polyoxyalkylene glycol such as polyethylene glycol or polytetramethylene glycol is particularly preferable.
When such a polyester is used as a prepolymer, it is possible to produce a composite vibration damping material having excellent adhesiveness and vibration damping performance.

Such a polyester, for example, comprises a dibasic acid and a glycol as main raw materials, is heated to 150 to 220 ° C., and is subjected to an esterification reaction under atmospheric pressure in the presence of a catalyst mainly composed of a metal salt. Esterification is performed, and then, under normal pressure or reduced pressure, 200 to 270 ° C.
A polyester having a desired molecular weight of a hydroxyl group can be synthesized by heating the above to distill off an appropriate amount of glycol.

In synthesizing the polyester, glycol is present in the desired polyester composition in an amount of 1.5-2.
It is preferable to add 0 times and synthesize. The polymerization catalyst is appropriately selected from ordinary catalysts composed of metal salts such as tetra-n-butoxytitanium, zinc acetate, antimony trioxide and potassium titanate oxalate.

When a dicarboxylic acid and a diol are used as alcohols, the polyester is essentially linear, and since the terminal is a hydroxyl group or a carboxylic acid, the number of functional groups (X) per molecular chain is usually two. This number can be increased by appropriately adding a trivalent or higher alcohol as an alcohol component or a trivalent or higher carboxylic acid as a carboxylic acid component at a stage of synthesizing a polyester so that gelation does not proceed. This is a known method.

Specific examples of other prepolymers that can be used are given below. Examples of the glycidyl ether of the polyol include glycols exemplified above as the polyester raw material or diglycidyl ethers of these polyglycols, and polyglycerol polyglycidyl ethers. Further, as the glycidyl ester, diesters obtained by glycidylating the molecular end of the polyester are exemplified. Examples include glycidyl polyester and polyglycidyl polyester.

As the polyamide, nylon 6, nylon 66, nylon 8, a polyamide resin synthesized from a lactam such as caprolactam or laurinlactam and an aminocarboxylic acid such as aminoundecanoic acid or aminododecanoic acid, or hexamethylenediamine, Examples include polyamides synthesized from organic diamines such as octamethylenediamine and aromatic dibasic acids or aliphatic dibasic acids previously exemplified as polyester raw materials. These examples are linear in nature and the ends of the polymer are carboxyl or amino groups. In this case, the number of functional groups (X) per one molecular chain is usually two. The number of functional groups can be adjusted easily by adding a small amount of trivalent amine or trivalent or higher carboxylic acid to such an extent that gelation does not proceed at an appropriate stage of the synthesis. is there.

As the modified polyolefin, maleic anhydride graft modified ethylene-propylene copolymer, maleic anhydride graft modified ethylene-vinyl acetate copolymer, maleic anhydride graft modified ethylene-ethyl acrylate copolymer, maleic anhydride graft modified polyethylene, maleic anhydride are used. Examples include graft-modified polypropylene and ethylene-methacrylic acid copolymers. By properly controlling the amount of maleic anhydride added to the polyolefin, the number of acid anhydride groups per one molecular chain can be adjusted.

Further, as a prepolymer, a frequency of 0.
It is preferable that the maximum value of the loss tangent (tan δ) based on the glass transition in the range of 1 to 20000 Hz is 0.5 or more. It can be said that the higher the tan δ is, the higher the vibration damping performance can be imparted to the prepolymer.
A particularly preferable value of an δ is 0.7 or more.

Low molecular weight compound (A) and low molecular weight compound
(B) In the first aspect of the present invention, the other raw material used for preparing the resin for the intermediate layer is a functional group capable of reacting with the functional group (X) of the prepolymer to form a covalent bond. A functional group (Y ') which reacts with a low molecular weight compound (A) having at least 2 groups, preferably 2 to 2.5 groups on average per molecule, and a functional group (X) to form a covalent bond.
The low molecular weight compound (B) has a higher number per molecule than the low molecular weight compound (A). The low molecular weight compound (B) is
It is preferable to have at least 3 functional groups (Y ′) on average per molecule, particularly 3 to 9 functional groups on average.

The functional group (Y) and the functional group (Y ') may be the same or different, but it is preferable that they are the same because the reaction can be easily controlled. Since the functional groups (Y) and (Y ′) react with the functional group (X) to form a covalent bond, the functional groups (Y) and (Y ′) depend on the type of the functional group (X). Change. Specifically, it is exemplified as follows.

Functional group (X) Functional group (Y) and (Y ') (1) Hydroxyl group, isocyanate group, acid anhydride group (2) Amino group, isocyanate group, acid anhydride group, epoxy group (3) Carboxyl group, epoxy group (4) ) Acid anhydride group hydroxyl group amino group epoxy group (5) epoxy group amino group acid anhydride group carboxyl group (6) isocyanate group hydroxyl group amino group

The low molecular weight compounds (A) and (B) have a molecular weight of up to about 5000, and specific examples include the following.

(I) Isocyanate group-containing low molecular weight compound 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (commonly called TDI), methylene-bis-4
-Phenyl isocyanate (commonly called MDI), polymethylene polyphenyl polyisocyanate or polyol modified MDI, such as commercially available Coronate 1040, Coronate 1050 (above, manufactured by Nippon Polyurethane), or carbodiimide modified MDI, such as Millionate MT.
MDI derivatives such as L and Millionate MTL-C (all manufactured by Nippon Polyurethane Co., Ltd.), hexamethylene diisocyanate (common name HDI) and its derivatives, isophorone diisocyanate (common name IPDI) and its derivatives, and TDI system in which TDI is added to trimethylolpropane. Adduct polyisocyanate, for example, as commercially available products, Coronate L, HL (above, Nippon Polyurethane), Dismophen L, Dismodur N (Sumitomo Bayer Urethane),
Polymerized polyisocyanate reacted in advance, for example, as commercially available products, Sprasec 3240, 3250, Coronate 2030, 2031 (Japan Polyurethane), Dismodur 1L, HL (Sumitomo Bayer Urethane),
Examples thereof include blocked isocyanates obtained by masking isocyanate with caprolactam and the like, and terminal isocyanate prepolymers obtained by previously reacting a low molecular weight polyether with the above-mentioned polyvalent isocyanate.

Blocked isocyanates are listed above as isocyanate group-containing compounds because they produce isocyanates upon heating.

(Ii) Epoxy group-containing low molecular weight compounds Bisphenol type epoxy compounds such as bisphenol A type, brominated bisphenol A type and bisphenol F type epoxy compounds, for example, commercially available TD-12
7, YD-7128, YDF-165 and YDB-40
0EK60 (above, Toto Kasei), EPICRON-83
0 (Dainippon Ink and Chemicals), o-cresol novolac epoxy compounds and other novolac epoxy compounds, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, glycerol polyglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether. , Polyglycidyl ethers such as propylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether, polyglycidyl amines such as tetrafunctional amine polyglycidyl amine, for example, YH-434 (Tohto Kasei) and diglycidyl phthalate as commercial products Glycidyl esters such as esters, diglycidyl hexahydrophthalate and diglycidyl-p-oxybenzoate Le acids, or alicyclic epoxy compound, for example commercially, ERL-4234 (Union Carbide) and the like. The epoxy equivalent of these epoxy compounds is preferably 250 or less.

(Iii) Low molecular weight compound containing an acid anhydride group Aromatic acid anhydride such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, etc. Aliphatic acid anhydride, polyadipic acid anhydride, polyazelaic acid anhydride,
Examples thereof include aliphatic acid anhydrides such as polysebacic acid anhydride.

(Iv) Amino group-containing low molecular weight compound Diethylenetriamine, chain-like aliphatic polyamines such as triethylenetetramine, cyclic aliphatic polyamines such as menthenediamine and isophoronediamine, aliphatic aromatic polyamines such as m-xylenediamine, meta Examples thereof include aromatic polyamines such as phenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

The low molecular weight compounds (A) and (B) containing the functional group (Y) or (Y ') are not limited to the above examples, but the functional group (Y) or the functional group per molecule intended is not limited. It is easy for those skilled in the art to appropriately select the compound according to the number of (Y ′). In addition, such a low molecular weight compound may be a mixture of those having different numbers of functional groups (Y) or (Y ′) per molecule inevitably in the production process of the low molecular weight compound. In that case, the number of the functional groups (Y) or (Y ') per molecule is of course the average value.

The prepolymer and the low molecular weight compound (A)
A preferred combination of (B) and (B) is a polyester in which the prepolymer has an average of 2 hydroxyl groups per molecular chain and the low molecular weight compound (A) has an average of 2 to 2. And the low molecular weight compound (B) is an isocyanate compound having an average of 3 to 9 isocyanate groups per molecule.

The ratio of the low molecular weight compounds (A) and (B) used to the prepolymer is such that the sum of the number of functional groups (Y) and the number of functional groups (Y ') is 0. 5-
The ratio is preferably 4.0 times, but most preferably 1.0 times, that is, the stoichiometric ratio. The low molecular weight compound (A) and the low molecular weight compound (B) are used so that the low molecular weight compound (A) accounts for 15 to 85% by weight, preferably 35 to 60% by weight, of the total of both.

In the first embodiment of the present invention, it is extremely important to use the low molecular weight compound (A) and the low molecular weight compound (B) having different numbers of functional groups per molecule, which makes it possible to use a wide temperature range. Guarantee that damping performance is exhibited in the range.

The object of the present invention is achieved by the use ratio of the low molecular weight compound (A) and the low molecular weight compound (B). That is, when only the low molecular weight compound (A) is used, the adhesiveness at high temperature is poor, and the vibration damping performance in a wide temperature range is not exhibited. Further, when only the low molecular weight compound (B) is used, the adhesive performance at high temperature is excellent, but the vibration damping performance in a wide temperature range is poor. By using both together,
Compared to the use of the low molecular weight compound (B) alone, there is a sacrifice in that the adhesiveness at a slightly high temperature is lowered, but the vibration damping performance is excellent in a wide temperature range. As a result, an excellent composite vibration damping material can be obtained as an overall evaluation, and its application is expanded.

Conductive Filler A conductive filler is blended in order to impart the spot weldability of the composite damping material. As the conductive material used for such a purpose, stainless steel, zinc, copper, tin, nickel, a metal material obtained by processing a metal such as brass into a powder, flakes, fibers, or a wire, copper, Alternatively, an iron-based metal plated with nickel or the like, a conductive carbon substance such as carbon black, graphite, or carbon fiber can be used. These conductive substances may be used alone or in combination of two or more. In order to develop good spot welding performance, it is preferable to select a metal substance. In order to develop better conductivity, it is necessary that the two metal plates be in a state capable of conducting electricity by the conductive substance.

Therefore, when the conductive material is powdery, the maximum particle size is obtained. When the conductive material is flake-like, the maximum thickness is obtained, and when it is fiber-like or wire-like. , And the maximum diameter of each representative length (L), in order to develop better conductivity,
If the ratio (L) / (T) of (L) and the thickness (T) of the resin layer containing a conductive substance is 0.5 or more, preferably 0.8 or more, current can be applied and spots can be applied. A damping material with excellent weldability can be obtained.

The filling amount of the conductive material is 0.5 to 1 in the resin.
The amount which occupies 0 vol% is preferable. Within this range, a vibration damping material having a good balance of spot weldability and vibration damping performance can be obtained.

The balance between the spot weldability and the high temperature adhesiveness of the vibration-damping composite material in which the conductive filler is mixed in the resin layer is closely related to the combined use of the low molecular weight compound (A) and the low molecular weight compound (B). There is. That is, when only the low molecular weight compound (B) is blended, the spot weldability is poor, but when the low molecular weight compounds (A) and (B) are used in combination, the high temperature adhesiveness is slightly sacrificed, but the spot weldability is improved. A composite damping material is obtained. This is demonstrated by the examples described below.

Operation of Manufacturing Composite Damping Material A method for manufacturing a composite damping material having a resin layer in the middle from the above-mentioned prepolymer, low molecular weight compound (A), low molecular weight compound (B) and conductive filler is described. An example is given below.

The prepolymer and low molecular weight compound used in the present invention are dissolved in a solvent, and additives such as conductive fillers and other stabilizers which are added as necessary are mixed.
The solvent may be appropriately selected depending on the prepolymer and low molecular weight compound used, but toluene, MEK, acetone, xylene, chloroform, MIBK, ethyl acetate or the like can be used. Such a mixture is applied to one surface of a metal plate to be laminated by a roll coater, a sprayer, a curtain flow coater, a doctor knife coater, etc., and heated at room temperature or preferably 100 to 200 ° C. to distill the solvent. Remove and heat press bond.

The coating thickness of the mixture is such that the finally obtained intermediate resin layer has a thickness of 1/50 to 1/5 of the thickness of one metal plate to be laminated. It is preferable that the thickness be substantially 20 to 150 μm. When it is less than 20 μm, the vibration damping property and adhesiveness are deteriorated, and when it exceeds 150 μm, it may cause displacement or cracking of the metal plate during molding.

The thermocompression bonding temperature is usually 130 to 130 ° C. for the mixture.
It suffices that heating at about 250 ° C. be applied. The contact time may be about 30 seconds to 2 minutes in the case of a heating press and about 1 to 10 seconds in the case of a heating roll. Alternatively, the metal plates may be preheated to the same temperature and laminated with a cooling press or a cooling roll.

In some cases, it may be manufactured by heating, melting and mixing, molding into a film, laminating this with a metal plate, and thermocompression bonding. Which process is adopted depends on the types of the prepolymer and the low molecular weight compound, and those skilled in the art can easily make a selection.

Second Aspect of the Present Invention Prepolymer (C) and Prepolymer (D) The prepolymer which can be used in the second aspect, except for the number of functional groups (X) per one molecular chain. The prepolymers described in the first aspect can be used as they are, including preferred prepolymers.

The number of functional groups (X) contained in one molecule of the prepolymer (C) is at least 2 on average, and preferably 2. The prepolymer (D) contains more functional groups (X ') per molecular chain than the number of functional groups (X) in the prepolymer (C). And it is 0.
It is preferable that the number is 5 or more and the average number is 2.5 to 4.5. The functional group (X) and the functional group (X ′) may be the same or different, but they are preferably the same from the viewpoint of easy control of the reaction.

By using the prepolymer in combination as described above, the adhesive performance at room temperature and high temperature, the adhesive retention after being exposed to high temperature, and the vibration damping performance in a wide temperature range as compared with the case where the prepolymer (C) is used alone. Is improved. Further, the vibration damping performance in a wider temperature range is improved as compared with the case of using the prepolymer (D) alone, and the spot welding performance when the conductive filler is mixed is improved.

For the purpose of enjoying the above-mentioned advantages, the weight ratio of the prepolymers (C) and (D) is 90 / 10-10.
/ 90, preferably 80/20 to 20/80.

As the compound which can be used as the low molecular weight compound, the compound described in the first aspect of the present invention can be used as it is. However, a low molecular weight compound having at least two functional groups (Y) on average per molecule is sufficient, and it is not necessary to use them together as in the first embodiment. The ratio of the low molecular weight compound used to the prepolymer can be determined by the ratio of the number of functional groups (Y) to the sum of the numbers of functional groups (X) and (X '), as in the first embodiment.

As the prepolymer (C), a polyester having an average number of hydroxyl groups per molecular chain of 2 is used, and as the prepolymer (D), the average number of hydroxyl groups per molecular chain is 2.
The most preferable combination is to use 5 to 4.5 polyesters and use an isocyanate compound having an average of 2 to 9 isocyanate groups per molecule as a low molecular weight compound. Regarding other types of metal plates, conductive fillers, preferable blending amounts, and composite vibration damping material manufacturing operations, first
The description of the embodiment is applicable as it is.

Third Aspect of the Invention For the metal plate and the prepolymer which can be used in the third aspect, the description of the prepolymer described in the first aspect is applied as it is, including the preferable aspect. Also, regarding the low molecular weight compound that can be used, the description of the first aspect is applied as it is, except that the number of the functional group (Y) per molecule is 2 or more. Of course, two types of low molecular weight compounds may be used, but the invention is not limited thereto.

The amount ratio of the prepolymer and the low molecular weight compound is the same as in the first embodiment. The most preferable combination is to use a polyester having an average of 2 hydroxyl groups per molecular chain as the prepolymer and an isocyanate compound having an average of 3 to 9 isocyanate groups per molecule as the low molecular weight compound.

This embodiment is characterized by the manufacturing operation of the composite vibration damping material. First, a prepolymer and a low molecular weight compound that reacts with the prepolymer are mixed and coated on at least one surface of two metals. Mixing can be performed by dissolving in a solvent. At this time, the coating amount is such that the thickness of the intermediate resin of the finally obtained composite vibration damping material is desired. Usually, the thickness is set to 10 to 100 μm after removing the solvent.

After coating, the solvent is removed, or before the solvent is removed, the prepolymer is dispersed on the coated surface. The prepolymer may be any one having a functional group (X ') that reacts with a low molecular weight compound, and may be the same as or different from the prepolymer used on the coated surface. May be.

The application amount is 5 to 70% by weight, preferably 10 to 50% by weight, based on the total amount of the applied prepolymer and the applied prepolymer. At the time of spraying, it may be in a solid state or a solution state. In the case of a solid, the shape may be any of powder, granules, flakes, pellets, and threads. When spraying, it should be avoided that the prepolymer on the coated surface is uniformly mixed. When mixed uniformly, the object of the invention may not be achieved.

Thereafter, the composite damping material of the present invention is manufactured by heating and pressure-bonding so that the coated surface is sandwiched between two metal plates. At this time, the heating temperature depends on the prepolymer used and the type of low molecular weight compound that reacts with it. For example, in the case of a hydroxyl group-containing polyester and an isocyanate compound,
Heat to 130-200 ° C. Moreover, the pressure is 2 to 30 kg.
/ cm ² G.

In the first to third aspects of the present invention, the progress of the reaction between the prepolymer having a functional group and the low molecular weight compound having a functional group varies depending on the type of the functional group. For example, in the case of a combination of a polyester having a hydroxyl group and an isocyanate compound having an isocyanate group, the reaction starts from the time when they are dissolved in a solvent, and the reaction is almost completed by heating and pressing the metal plate, and a crosslinked resin is formed. To do.

Depending on the types of functional groups of the prepolymer and the low molecular weight compound, the time and temperature for a series of operations such as solution preparation, coating on a metal plate, removal of the solvent, and pressure bonding of the metal plate should be appropriately selected. is there. Those skilled in the art can experimentally determine optimum conditions.

According to the first to third aspects of the present invention described in detail above, a composite vibration damping material exhibiting vibration damping performance in a wide temperature range can be obtained. The reason is speculated as follows. ..

When a flexible resin having a low crosslink density is applied as the resin layer, it exhibits high vibration damping performance at around room temperature (low temperature) as indicated by the broken line a in the graph shown in FIG. On the other hand, when a resin having a high cross-linking density is applied as the resin layer, it exhibits high vibration damping performance at high temperature as indicated by a broken line b in FIG. Here, since the resin layer of the damping material of the present invention has a high cross-linking density part and a low cross-linking density part in a distributed manner, the vibration-damping performance at around room temperature has a low cross-linking density part having flexibility, It is presumed that the vibration damping performance in (1) is exhibited in the portion where the crosslink density is high, and as shown by the solid line in FIG. 2, high vibration damping performance can be obtained in a wide temperature range.

The composite damping material produced by the method of the present invention is not only used for stairs, doors, floor materials, etc., but also for oil pans of engines, automobile body parts, dash panels, floor panels, roof panels, etc. In the past, it was possible to use composite vibration damping materials for applications where it was difficult to use, or for motors and compressor covers, etc.
It can be widely used in various industries, such as the civil engineering and construction industry, the automobile industry, and the electrical machinery industry.

[0072]

EXAMPLES The present invention will be described below with reference to examples.

In this embodiment, under the following conditions,
A composite vibration damping material was produced by interposing a resin composition between two metal plates and used as samples. The performance evaluation test method for each sample and the physical property test method for the resin are as follows.

Damping performance As evaluation of the damping performance, the loss coefficient η of the composite damping material sample
It was measured by a mechanical Inn Portland dance method, 1000H _Z
We investigated the temperature dependence of the loss factor in. η is 0.1
It can be judged that the vibration damping property is excellent when it is above.

Adhesive Performance (1) T-Peel Strength: A sample of the composite damping material prepared to have a width of 25 mm was measured according to JIS K-6854 at a tensile speed of 200 mm / min and a room temperature of 23 °. (2) Shear adhesive strength: Tensile strength of 10 mm / min at room temperature of 23 ° C. according to JIS according to the sample of the composite damping material prepared so as to have an adhesive area of 25 mm × 12.5 mm
It was measured according to K-6850.

Heat Resistant Adhesion Performance A sample processed in the same manner as in (2) above was tested at a pulling speed of 1
JIS K- at 0 mm / min at a measurement temperature of 10 to 80 ° C.
Measured according to 6850.

Molding Workability Performance A sample of the composite vibration damping material obtained by cutting each composite vibration damping material into a width of 25 mm × 100 mm was bent to 4 mmφ, and a product with a float in the bent portion was marked with X and no change. Is indicated by a circle.

Retention of Adhesive Performance after High Temperature Treatment A sample prepared so as to have an adhesive area of 25 mm × 12.5 mm was placed in an oven and heat-treated in air at 200 ° C. for 1 hour. After heat treatment, the above adhesive performance test (
Similarly to (2)), the room temperature 23 ° C. shear adhesive strength was measured. The adhesive strength retention rate shown in the following formula was used for evaluation. (Shear adhesive strength after heat treatment / Shear adhesive strength before heat treatment) × 100 (%)

Spot Welding Performance Two samples cut to a width of 100 mm and a length of 160 m were stacked and direct spot welding was performed under the following conditions. Pressurization force: 200 kg, current: 8 KA Number of energization cycles: 8, Electrode: 8R spherical shape Spot welding point interval: 20 mm A normal nugget diameter was made successful. 40-point welding was performed with the samples stacked, and the success rate was shown as a percentage.

Glass transition point: Measured with a differential scanning calorimeter (DSC) in a nitrogen atmosphere at a heating rate of 10 ° C./min. The endothermic start temperature and endothermic end temperature based on the glass transition are displayed. In addition, when simply displaying as a glass transition point, it indicates the temperature at the point of the minimum of the differential value of the endothermic curve drawn by DSC.

Number average molecular weight The number average molecular weight of the thermoplastic resin was obtained by dissolving the thermoplastic resin in tetrahydrofuran and measuring it by liquid chromatography to calculate the number average molecular weight in terms of polystyrene.

Example 1 The following were prepared as prepolymers. Prepolymer A terephthalic acid residue 45, sebacic acid residue 55, ethylene glycol residue 45, neopentyl glycol residue 55
Polyester synthesized by a conventional method at a molar ratio of. Number average molecular weight: 15,000 Glass transition point: -15 ° C Number of crosslinkable functional groups (hydroxyl groups): 2 pieces / 1 molecular chain prepolymer B To the constituent raw materials of the thermoplastic resin A, trimethylolpropane or pentaerythritol is further added. , 2 kinds of polyester synthesized by a conventional method. Number average molecular weight: 20000 Glass transition point: -10 ° C. Number of crosslinkable groups (hydroxyl groups): Average of 3 chains / 1 molecular chain or Average of 4 chains / 1 molecular chain

Each of these prepolymers was dissolved in a mixed solvent of toluene and methyl ethyl ketone to obtain a prepolymer solution having a solid content of 25% by weight. The mixture obtained by mixing the above two kinds of solutions and removing the solvent showed compatibility (no phase separator having a diameter of 1 μmφ or more).

The following compounds were used as the isocyanate compound. Isocyanate compound A carbodiimide-modified diisocyanate (trade name: Millionate MTL-C, manufactured by Nippon Polyurethane Company)

[Chemical 1] However, the triisocyanate compound is contained in an amount of about 30% by weight, the number average molecular weight is 340, and the average number of isocyanates per molecule is 2.3.

Isocyanate Compound B Polymerizable triisocyanate (trade name Coronate 2030, solid content of Nippon Polyurethane Co., 50%, butyl acetate solvent) provided that about 30% by weight of a compound containing 4 or more isocyanate groups in one molecule. Containing, number average molecular weight is 215
0, the average number of isocyanate groups per molecule is 6.2
It is an individual.

The solutions of the above prepolymers A and B were mixed at the weight ratios shown in Table 1, and an equivalent amount of the isocyanate compound was mixed therewith to obtain a mixed solution of the prepolymer and the isocyanate compound.

Further, a nickel filler (average particle size: 65 μm) as a conductive substance was added to this mixed solution so that the final content was 3% by volume with respect to the intermediate resin layer.

The mixed solution (mixture) thus obtained was degreased and cold rolled to a thickness of 0.8 mm (SPCC-SD).
It is coated with a roll coater in an oven (100
The solvent was distilled off at (° C. in air × 3 minutes).

Immediately thereafter, the surfaces coated with the mixed solution were laminated together and hot-pressed (180 ° C. × 2 minutes × pressure 5 Kgf /
Heat-bonding was performed at cm ² ) to obtain various composite damping material samples.

[0090]

[0091]

[0092]

[Table 1]

[Table 2]

Example 2 The following were used as prepolymers. Prepolymer C terephthalic acid residue 60, adipic acid residue 40, ethyne glycol residue 60, 1,6-hexanediol residue 40
The number average molecular weight: 10,000, glass transition point: -15 ° C, the number of functional groups (hydroxyl groups): 2 / one molecular chain, the prepolymer C was dissolved in a mixed solvent of toluene and methyl ethyl ketone. Then, a solution having a solid content of 25% by weight was prepared. The prepolymer solution and the isocyanate compound were mixed at a mixing ratio shown in Table 3 to obtain a mixed solution of the prepolymer and the isocyanate compound. The total amount of the isocyanate groups of the isocyanate compound A and the isocyanate compound B was added so as to be equivalent to the hydroxyl groups at both ends of the molecular chain of the prepolymer C.

A nickel filler having an average particle size of 65 μm was sprayed on the mixed solution application surface so that the final concentration was 3% by volume with respect to the intermediate resin layer. Then, oven (100 ℃
The solvent was distilled off (in air for 3 minutes). Immediately after this, the surfaces coated with the mixed solution were laminated together and hot-pressed (180
Heat-bonding was conducted at a temperature of 2 minutes and a pressure of 5 Kgf / cm ² ) to obtain various composite damping material samples. The performance evaluation is shown in Table 4. Further, the relationship between the heat resistant adhesiveness and spot weldability and the isocyanate compound B content ratio is shown in FIG.

[0095]

[Table 3]

[0096]

[Table 4]

Example 3 The following were used as prepolymers. Prepolymer D terephthalic acid residue 60, sebacic acid residue 40, ethylene glycol residue 60, 1,6-hexanediol residue 4
Polyester synthesized by a conventional method at a molar ratio of 0. Number average molecular weight: 15,000 Glass transition point: -18 ° C Number of functional groups (hydroxyl groups): 2/1 molecular chain

Prepolymer E terephthalic acid residue 75, isophthalic acid residue 25, ethylene glycol residue 40, 1,6-hexanediol residue 50, polyethylene glycol (number average molecular weight 100
0) Polyester composed by a molar ratio of residues 10 and synthesized by a conventional method Number average molecular weight: 20000 Glass transition point: 10 ° C. Number of functional groups (hydroxyl groups): 2 pieces / 1 molecular chain

Prepolymer D was dissolved in a mixed solvent of toluene and methyl ethyl ketone to obtain a prepolymer D solution having a solid content of 25% by weight. Further, the prepolymer E was a powder having an average particle size of 50 μm.

The isocyanate compound used in Example 1 was used as the isocyanate compound.

The prepolymer D solution and the isocyanate compound B were mixed to prepare a mixed solution.

Further, in a mixed solution of the prepolymer D and the isocyanate compound B, an average particle size of 65 as a conductive substance is obtained.
The nickel filler of μm was mixed so that the final content was 3% by volume with respect to the intermediate resin layer. The mixed solution (mixture) thus obtained was applied to a degreased 0.8 mm thick cold-rolled steel sheet (SPCC-SD) using a roll coater, and the solvent was distilled off in an oven (100 ° C. in air × 3 minutes). Left. Immediately thereafter, the powder of the prepolymer E was sprinkled on the coated surface of the mixed solution, the surfaces coated with the mixed solution were put together, and the same steel sheets were laminated, and hot pressed (180 ° C. × 2 minutes × pressure 5 Kgf / Heat-bonding was performed at cm ² ) to obtain various composite damping material samples.

Comparative Example 3-1 is an example in which the prepolymer E is not dispersed, Comparative Example 3-2 is an example in which the prepolymer E is not dispersed and the prepolymer E is used in place of the prepolymer D, and Comparative Example 3-3. Is the isocyanate compound B in Comparative Example 3-2.
In Example 3-2, in which Prepolymer E was not added, the prepolymer E was sprayed before the solvent was distilled off (see Table 5).

[0104]

[0105]

[Table 5]

[0106]

The composite damping material produced by the production method of the present invention has good damping performance in a wide temperature range. Furthermore, it has an adhesive strength at room temperature that can withstand press molding, has excellent adhesiveness even in the temperature range in which it is used, and retains the adhesive strength even after a coating baking process. Further, by adding a conductive filler, a vibration damping material having excellent spot weldability can be obtained. Therefore, the vibration damping material obtained by the method of the present invention is suitable for use in various fields, including fields such as automobiles where spot weldability is required.

[Brief description of drawings]

FIG. 1 is a schematic view showing the reason why the composite damping material produced by the method of the present invention exhibits excellent damping performance.

FIG. 2 is a graph showing the relationship between the content of an isocyanate compound having 3 or more isocyanate groups per molecule and the shear adhesive strength and spot weldability.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location F16F 15/02 Q9138-3J (72) Inventor Makoto Sakamoto 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd.Technology Research Headquarters (72) Inventor Tomojige Ono 1 Kawasaki-cho, Chiba City, Chiba Prefecture Kawasaki Steel Co., Ltd. Technical Research Division

Claims (23)

[Claims] 1. A prepolymer having at least two functional groups (X) on average per one molecular chain and one molecule of a functional group (Y) capable of reacting with the functional group (X) to form a covalent bond. Low molecular weight compound (A) having at least two per unit
And a low molecular weight compound (B) in which the number of functional groups (Y ′) capable of reacting with the functional group (X) to form a covalent bond per molecule is higher than that of the low molecular weight compound (A). Two metal plates sandwich the resin obtained by reaction under the condition that the molecular weight compound (A) is present in an amount of 15 to 85% by weight of the total amount of the low molecular weight compound (A) and the low molecular weight compound (B). A method for producing a composite damping material in which a resin layer is sandwiched between two metal plates, which is characterized in that 2. The method for producing a composite vibration damping material according to claim 1, wherein the prepolymer is a saturated polyester. 3. The number average molecular weight of the prepolymer is 7,000.
It is-50,000, It is characterized by the above-mentioned.
A method for manufacturing the composite vibration damping material according to any one of 1. 4. The method for producing the composite vibration damping material according to claim 1, wherein the low molecular weight compound (A) and the low molecular weight compound (B) are isocyanate compounds. 5. The low molecular weight compound (A) has an average of 2 per molecule.
An isocyanate compound containing 1 to 2.5 isocyanate groups, wherein the low molecular weight compound (B) is an isocyanate compound containing an average of 3 to 9 isocyanate groups per molecule. A method for manufacturing the composite vibration damping material according to any one of 1. 6. The method for producing a composite vibration damping material according to claim 1, wherein the resin is mixed with a conductive filler. 7. A solution containing a prepolymer, a low molecular weight compound (A), a low molecular weight compound (B) and, if necessary, a conductive filler is applied to at least one surface of two metals, and after removing the solvent, The method for producing a composite vibration damping material according to any one of claims 1 to 6, wherein the coated surface is pressure-bonded so as to be sandwiched between two metal plates and heated. 8. A prepolymer (C) having at least two functional groups (X) on average per one molecular chain and more functional groups (X ') per one molecular chain than the prepolymer (C). The prepolymer (D) and a low molecular weight compound having at least two functional groups (Y) capable of reacting with the functional group (X) and the functional group (X ′) to form a covalent bond per molecule on average. Under the condition that the prepolymer (C) is present in an amount of 10 to 90% by weight based on the total amount of the prepolymer (C) and the prepolymer (D), the resin obtained by the reaction is operated so as to be sandwiched between two metal plates. A method for producing a composite vibration damping material in which a resin layer is sandwiched between two metal plates. 9. The method for producing a composite vibration damping material according to claim 8, wherein the prepolymer (C) and the prepolymer (D) are saturated polyesters. 10. The composite vibration damping material according to claim 8, wherein the prepolymer (C) and the prepolymer (D) have a number average molecular weight of 7,000 to 50,000. Manufacturing method. 11. The method for producing a composite vibration damping material according to claim 8, wherein the low molecular weight compound is an isocyanate compound. 12. The prepolymer (C) contains an average of 2 functional groups (X) per molecular chain, and the prepolymer (D) contains an average of 2.5 to 4 functional groups (X ') per molecular chain. The method for producing a composite damping material according to any one of claims 8 to 11, wherein the composite damping material contains 5 pieces. 13. The method for producing a composite vibration damping material according to claim 8, wherein a conductive filler is mixed with the resin. 14. A solution containing a prepolymer (C), a prepolymer (D), a low molecular weight compound and, if necessary, a conductive filler is applied to at least one surface of two sheets of metal, and the solvent is removed and then applied. The method for producing a composite vibration damping material according to any one of claims 8 to 13, wherein the surface is crimped so as to be sandwiched between two metal plates and heated. 15. A prepolymer having at least two functional groups (X) on average per one molecular chain and one molecule of a functional group (Y) capable of reacting with the functional group (X) to form a covalent bond. It is possible to mix a low molecular weight compound having an average of at least two per unit, apply the mixture to at least one surface of two metal plates, and react with the functional group (Y) on the applied surface to form a covalent bond. A prepolymer having an average of at least two functional groups (X ') per molecular chain is dispersed, and then pressure-bonded so that the coated surface is sandwiched between the two metal plates. A method for manufacturing a composite damping material in which a resin layer is sandwiched. 16. The method for producing a composite vibration damping material according to claim 15, wherein the prepolymer is a saturated polyester. 17. The number average molecular weight of the prepolymer is 7,000.
It is 0-50,000, The manufacturing method of the composite damping material in any one of Claim 15 or 16 characterized by the above-mentioned. 18. The method for producing a composite vibration damping material according to claim 15, wherein the low molecular weight compound is an isocyanate compound. 19. The low molecular weight compound has an average of 3 to 9 per molecule.
The method for producing a composite vibration damping material according to any one of claims 15 to 18, which is an isocyanate compound containing one isocyanate group. 20. The method for producing a composite vibration damping material according to claim 15, wherein a conductive filler is further mixed with the mixture of the prepolymer and the low molecular weight compound. 21. The method for producing a composite vibration damping material according to claim 15, wherein the mixture of the prepolymer and the low molecular weight compound is in the form of a solution. 22. The method for producing a composite vibration damping material according to claim 15, wherein the prepolymer to be sprayed is in a solid state. 23. A composite vibration damping material produced by the method according to any one of claims 1 to 22.