JP2818254B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a structural adhesive having excellent vibration damping properties and excellent heat resistance properties over a wide temperature range from extremely low temperatures to high temperatures. First, the present invention relates to a novel resin composition effectively used for various kinds of applications.

[Conventional technology]

When assembling structures such as aircraft and automobiles, structural adhesives use rivets,
It is used in place of conventional joining methods such as bolts and welding. Further, it is used as a weld bonding method used in combination with a conventional bonding method.

On the other hand, in recent years, the problem of noise and vibration is becoming a social problem, and measures for environmental improvement are strongly desired. There is a strong demand for imparting sound insulation performance and vibration damping performance to vehicle materials, building materials, electrical components, etc., and damping materials and damping steel plates are used. The structural strength of the material is low, and the processability and adherence to a constrained layer such as a steel plate are poor in processing.

In the conventional structural adhesive, the vibration damping property is recognized in a narrow temperature range, but the vibration damping performance over the entire use environment temperature is insufficient. At present, the use of an adhesive for vibration damping that matches the operating environment temperature is selected and used, and there is no adhesive for structural damping for applications in a wide range of environmental temperatures, and thus does not satisfy social demands.

As is apparent from the above description, there is a strong demand for structural adhesives and resin compositions that exhibit excellent vibration damping performance and adhesive properties particularly over a wide temperature range.

As described above, a structural adhesive is an adhesive having a high adhesive property. The adhesive has a small decrease in the adhesive property even when a large load is applied for a long time, and is a highly reliable adhesive. Nitrile-phenolic, nitrile-epoxy Although high-molecular substances such as modified epoxy, modified acryl, and polyimide are used as main components, they cannot exhibit vibration damping properties over a wide temperature range because of their high rigidity. In order to improve the vibration damping properties, the resin composition must have high vibration energy absorption.

An ordinary epoxy resin composition is in a glassy state at room temperature, and therefore, has a very high shear bond strength but a very low peel bond strength. One way to increase energy absorption in such systems is to add plasticizers or flexibility agents. According to this method, the elastic modulus and the glass transition temperature are decreased, and the peel adhesive strength is improved, but the shear adhesive strength and heat resistance are decreased.

There is another method of adding a liquid rubber or the like, and there are many reports on the modification of an epoxy resin with a carboxyl group-terminated acrylonitrile-butadiene copolymer (CTBN), but the temperature dependence of vibration damping properties is not so much improved. This phenomenon can be explained by the fact that both polymers became intermolecularly compatible by the reaction.

Although ordinary polymer alloys are intended to utilize the compatibility between different polymers or to realize various morphologies and physical properties based on them under the restrictions, as described above, there is no No effect is seen. Further, even if a polymer alloy of a different polymer having poor compatibility is adopted, only a resin composition having two so-called two damping characteristic peaks can be obtained. In addition, this composition is inherently poor in compatibility, has extremely poor uniform dispersibility and storage stability, and cannot be practically used.

Therefore, an IPN (interpenetrating network polymer) method has been considered, which has resulted in an increase in the elastic modulus and an increase in the glass transition temperature as compared with a normal polymer alloy. As for the IPN method, there are reports on polyacrylate-polystyrene, polyacrylate-urethane, polybutadiene-polyacrylonitrile-butadiene, and urethane-urea systems, but there is no practical example as an adhesive or a resin composition. Further, even if the present inventors evaluated the vibration damping characteristics, they did not improve the temperature dependency.

On the other hand, as a composition example, JP-A-59-159866,
JP-A-63-186786 proposes an adhesive composition. These adhesive compositions are excellent in oil-surface adhesion, but are not sufficient in terms of vibration damping properties.

[Problems to be solved by the invention]

It is considered that the above-mentioned IPN method can provide a new degree of freedom apart from the restriction of compatibility between different polymer components.
The present inventors have conducted intensive studies and, as a result, have succeeded in developing a completely novel resin composition having less temperature dependence in vibration damping characteristics and excellent heat resistance characteristics.

INDUSTRIAL APPLICABILITY The present invention exhibits excellent vibration damping properties and adhesive properties especially over a wide temperature range from extremely low temperatures to high temperatures, and also has excellent heat resistance properties, and is effectively used for various applications including structural adhesives. An object is to provide a novel resin composition.

[Means for solving the problem]

In order to solve the above problems, the resin composition of the present invention comprises: (a) an epoxy resin, (b) an acrylonitrile-butadiene copolymer having a vinyl group at both terminals, and (c) at least one acryloyl group ( (D) an organic peroxide, and (e) an epoxy resin curing agent.

As the epoxy resin (a) of the present invention, an epoxy compound having an average of one or more epoxy groups in one molecule, which is used as a component of an ordinary epoxy resin-based adhesive, can be used. Specific examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol
AD type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, aliphatic glycidyl ester type epoxy resin, aliphatic glycidyl ether type epoxy resin, aromatic glycidyl ester type epoxy resin, aromatic glycidyl ether type epoxy resin,
Multifunctional epoxy resin, various halogenated epoxy resins,
Examples thereof include a dimer acid-modified epoxy resin, an oil-modified epoxy resin, a cycloaliphatic epoxy resin, a glycidylamine type epoxy resin, a heterocyclic epoxy resin, and a hydantoin type epoxy resin.

Further, as the epoxy resin (a) of the present invention, an acrylonitrile-butadiene-modified epoxy resin (hereinafter, referred to as a rubber-modified epoxy resin) can be used. For example, a rubber-modified epoxy resin obtained by copolymerizing a bisphenol A type epoxy resin or a bisphenol F type epoxy resin with a carboxyl group-terminated acrylonitrile-butadiene copolymer or an acrylonitrile-butadiene copolymer can be used. Representative products of this type include Adeka Resin EP-4023 (made by Asahi Denka Kogyo Co., Ltd.), Adeka Resin EP-4024 (made by Asahi Denka Kogyo Co., Ltd.), and Adeka Resin EP-4026 (made by Asahi Denka Kogyo Co., Ltd.). Can be mentioned.

Further, as the epoxy resin (a) of the present invention, a urethane-modified epoxy resin can be used. For example, a liquid urethane-modified epoxy resin having a skeleton of a copolymer of bisphenol A type epoxy, a polyether polyol or a polyester polyol, and a terminal isocyanate group-containing urethane prepolymer obtained from an organic polyisocyanate can be used. Representative products of this type include Adeka Resin EPU-6 (manufactured by Asahi Denka Kogyo), Adeka Resin EPU-7A (manufactured by Asahi Denka Kogyo), Adeka Resin EPU-73 (manufactured by Asahi Denka Kogyo), Adeka resin EPU
-79 (manufactured by Asahi Denka Kogyo KK) and the like.

As the acrylonitrile-butadiene copolymer (b) having a vinyl group at both ends of the present invention, a liquid rubber having the following structural formula and a molecular weight of about 1,000 to 7000 can be exemplified.

(In the above formula, X = about 5, Y = about 1, m = about 10, R:
Functional groups having a polar group such as a vinyl group, a hydroxyl group, or an epoxy group at the terminal are shown. ) Typical products of this type include hiker VTBNX1300 × 23 (BF Goodrich), hiker VTBNX1300 × 33 (BF Goodrich), hiker HTBNX1300 × 17 (BF Goodrich), hiker ETBN1300 × 40 ( BF Goodrich)
And the like. In particular, those having a vinyl group are preferred.

As the (meth) acrylate having at least one acryloyl group (c) of the present invention, a compound having the following structural formula can be exemplified. In addition, (meth) acrylate is
A generic term for acrylate and / or methacrylate.

In addition to the above compounds, neopentylglycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,5-pentadiol di (meth) acrylate, 1,6-hexanediol di (meth) Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate,
Examples thereof include tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, allyl glycidyl ether, and (meth) acrylic acid adducts of epoxy esters.

As the organic peroxide (d) of the present invention, known organic peroxides, for example, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, peroxyester In addition, a peroxide containing silane, phthalic acid ester or the like can be used.

In addition, organic acid salts or inorganic acid salts such as iron, cobalt, manganese, and vanadium, or known accelerators such as ascorbic acid and gallic acid can be used in combination.

The resin composition of the present invention is crosslinked by heating, and an organic peroxide and an accelerator to be used are selected depending on heating conditions.

As the epoxy resin curing agent (e) of the present invention, known epoxy resin curing agents and / or curing accelerators can be used. However, since the resin composition of the present invention can be cured by heating. What is called a latent curing agent and / or a latent curing accelerator may be selected from those that meet the curing conditions. For example, one or two of general dicyandiamide, a hydrazide compound, an imidazole epoxy resin adduct, an alkyl urea compound, and the like.
More than one type may be used.

 Each of the above components is blended in the following ratio.

By mixing 10 to 80 parts by weight of the component (b) and 5 to 50 parts by weight of the component (c) with respect to 100 parts by weight of the component (a), the effects of the present invention can be achieved.

The components (d) and (e) may be added in appropriate amounts according to the mixing ratio of the other components.

The resin composition of the present invention is adjusted by uniformly mixing the above components at a predetermined ratio using a defoaming mixer, a three-roll mill, a ball mill, or the like. For example, viscosity modifiers, adhesion promoters, fillers, pigments, dyes, conductivity promoters, leveling agents, dispersants, flame retardants (flame retardants), plasticizers, organic solvents, thermoplastic polymer compounds, stabilization An agent, an antifoaming agent, a coupling agent, a rust inhibitor, a fragrance and the like may be added.

As the viscosity adjusting agent, a known viscosity reducing agent and a thixotropic agent used for an epoxy resin adhesive may be used.
As the viscosity reducing agent, those having a reactive group such as aliphatic diglycidyl ether, triglycidyl ether of trimethylolpropane, and diglycidyl ether of polyoxyalkylene glycol are preferable. As the thixotropic agent, colloidal silica and an organic bentonite compound are preferable.

N-β- (aminoethyl)-
Silane-based adhesion promoters such as γ-aminopropyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane, and oil-surface adhesion promotion such as 2-hydroxyethyl (meth) acryloyl phosphate, nitrogen-containing (meth) acrylate and epoxy acrylate Agents and the like can be used.

As a filler, a general extender can be used as a matter of course, but a known filler that improves vibration damping characteristics is particularly preferable. For example, layered compounds (mica, graphite, molybdenum disulfide, boron nitride, etc.), acicular compounds (zonolite, potassium titanate, asbestos, carbon fiber, etc.), granular compounds and plate compounds (ferrite, talc, vermiculite, kaolin, Clay, etc.). Further, as the filler, a silane coupling agent, a titanate coupling agent, or the like may be used in combination, or a filler which has been previously surface-treated with them may be used.

The conductivity-imparting agent is, for example, acetylene black, Ketjen black, a carbon-based filler such as carbon fiber, a metal oxide-iron oxide sintered composite ferrite, α- It is possible to use iron oxide particles, various metal powders, metal-based ferrers such as metal fibers, metal compounds, metal composite fillers coated with metal, and the like.

The thermoplastic polymer compound is used for improving vibration damping performance in a specific temperature range and for improving durability performance. For example, polybutadiene, polybutadiene having a polar group, acrylonitrile-butadiene copolymer, acrylic rubber, chloropropylene rubber, urethane rubber, ethylene-vinyl acetate copolymer, chlorosulfonated polyethylene, ethylene-acrylic acid copolymer, thermoplastic Polyurethane, saturated polyester, nylon, polyethylene, polybutene, polyisobutylene, silicone rubber, polysulfide rubber, butyl rubber, urethane-acrylate copolymer, urethane-thiochol copolymer, coal tar, bitumen, etc. Good.

The stabilizer is appropriately selected from known degradation inhibitors, polymerization inhibitors and the like in consideration of the composition, and may be used alone or in combination of two or more. In particular, to improve the storage stability, hydroquinone, hydroquinone monomethyl ether, phenols such as 2,6-di-t-butyl-4-methylphenol alone or an amine salt such as N-nitrosophenylhydroxylamine, It is preferable to use an organic tin compound in combination.

[Action]

Since the resin composition of the present invention has excellent vibration damping properties and adhesive properties from a very low temperature to a high temperature range, it is expected to have extremely good use as a structural adhesive, It is effectively used as an adhesive for molding, and is also suitable as a cast product or a molded product used for a vibrating portion of an electric component or the like.

〔The invention's effect〕

As described above, the resin composition of the present invention combines excellent vibration damping properties and adhesive properties over a very low temperature range to a high temperature range in a general use environment, and has heat resistance and durability. It is particularly useful as a structural adhesive and an adhesive for vibration-damping steel sheets. It is also suitably used as a cast product or a molded product, and is used industrially effectively.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist of the present invention.

Examples 1 to 6 and Comparative Examples 1 to 3 The compositions shown in Table 1 were prepared by uniformly mixing them using a defoaming mixer.

The results of various tests conducted on these compositions are shown in Table 2 and FIGS. 1 and 2.

The shear bond strength and peel bond strength tests are JISK
Performed based on 6850 and JISK6854. However, the test piece materials are SPCC-SD steel plates specified in JISG3141 and have a thickness of about 1.6 mm and about 0.8 mm, respectively.
55, manufactured by Idemitsu Petrochemical Co., Ltd.) and left vertically for 24 hours. The adhesive was cured at 170 ° C. for 20 minutes. The pulling speed in the test is 50mm / min and 200mm / min, respectively.
The bonding strength of each is 20 ° C atmosphere and 100 ° C
Each was measured in an atmosphere.

The mechanical loss coefficient was measured using a torsional free damping type viscoelasticity measuring device (RD-1100AD, manufactured by Resca Corporation).

Preparation of cured product: Teflon-coated steel plate having a thickness of about 2 mm is sandwiched with a liquid substance using a 1 mm spacer, and the weight is about 5 kg / cm ²
Press for 5 minutes. Then put it in the oven for 170
Cured at 20 ° C for 20 minutes to obtain a sheet-shaped cured product with a thickness of about 1 mm. Then, the cured product is cut into a width of 5 mm and a length of 100 mm to obtain a sample for a viscoelasticity measuring device.

Measurement method of mechanical loss coefficient: The above-mentioned sample was measured from -50 ° C to + 150 ° C at a torsion angle of about 1 ° using the torsional free damping type viscoelasticity measuring apparatus.

The explanation of the notes in Table 1 is as follows.

1) Bisphenol A type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.) 2) Dimer acid-modified epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.) 3) Castor oil-modified epoxy resin (AC R Co., Ltd.) 4) Rubber-modified epoxy resin (manufactured by Asahi Denka Kogyo Co., Ltd.) 5) Urethane-modified epoxy resin (manufactured by Asahi Denka Kogyo Co., Ltd.) 6) Glycidyl methacrylate-modified acrylonitrile-butadiene having vinyl groups at both ends Coalescing (BF
7) PEG # 200 diacrylate (manufactured by Kyoeisha Yushi Kagaku Kogyo KK) 9) Diluted product of t-butylperoxy-2-ethylhexanoate in 50% dimethyl phthalate (manufactured by NOF Corporation) 10) 3- (3,4-dichlorophenyl) -1,1-dimethylurea (Maruwa Bio) Chemical Co., Ltd.) As is clear from the results in Table 2 above, the resin composition of the present invention has excellent heat resistance, excellent oil surface adhesiveness, and excellent performance as a structural adhesive. It could be confirmed.

Also, as shown in FIGS. 1 and 2, it was confirmed that the resin composition of the present invention had excellent vibration damping properties over a wide temperature range from extremely low to high temperatures.

[Brief description of the drawings]

FIG. 1 is a graph showing the mechanical loss coefficients of Examples 1 to 6, and FIG. 2 is a graph showing the mechanical loss coefficients of Comparative Examples 1 to 3.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 63/00-63/10 C08L 9/02 C09J 163/00-163/10 C09J 109/02

Claims (3)

(57) [Claims] 1. An epoxy resin, (b) an acrylonitrile-butadiene copolymer having vinyl groups at both ends, (c) a (meth) acrylate having at least one acryloyl group, and (d) an organic peroxide. And (e) an epoxy resin curing agent. 2. The composition according to claim 1, wherein the component (b) and the component (c) in the item (1) have no polar group having reactivity with the epoxy resin. Resin composition. 3. A method according to claim 1, wherein 100 parts by weight of the component (a) is
The resin composition according to (1) or (2), wherein 10 to 80 parts by weight of the component (b) and 5 to 50 parts by weight of the component (c) are blended.