JPWO2009041445A1 - Anaerobic curable composition - Google Patents

Abstract

The present invention relates to a conductive anaerobic curable adhesive having excellent storage stability and adhesiveness. The present invention relates to (a) a compound having at least one radically polymerizable functional group in the molecule, (b) an organic peroxide, (c) o-benzoixsulfimide, (d) an ionic liquid compound: ( anaerobic curable composition comprising 1 to 40 parts by weight per 100 parts by weight of component, (e) conductive powder: 0.1 to 10 parts by weight per 100 parts by weight of component (a) I will provide a.

Description

  The present invention relates to an anaerobic curable adhesive, and more particularly to an anaerobic curable composition having electrical conductivity.

  The anaerobic curable composition is based on a (meth) acrylic acid ester monomer, is stable while in contact with air or oxygen, is kept in a liquid state for a long time without gelation, Or it has the property of rapidly curing when oxygen is blocked or eliminated. Utilizing these properties, anaerobic curable compositions are used for bonding screws, bolts, etc., fixing, fixing fitting parts, bonding between flange surfaces, sealing, filling burrows in cast parts, etc. Yes.

  When an anaerobic curable composition is used as an adhesive, it has rapid curing properties at room temperature and has stable physical properties even after curing, so that it has been used for adhesion of electrical parts. However, since the anaerobic curable composition is insulative, the parts bonded using the anaerobic curable composition are not electrically conductive. This does not cause a problem depending on the location of use, but there are locations that require electrical conductivity depending on the particular application. For example, there is a problem in bonding a support member such as a suspension of a floating magnetic head unit in a hard disk drive and a magnetic head slider. At this location, the slider is flying between the flying surface of the magnetic head slider and the disk surface, and the flying height of the slider is very small relative to the disk surface rotating at high speed. appear. The generated static electricity is charged and may damage the head device and media due to the electrostatic breakdown phenomenon.

  The invention disclosed in Patent Document 1 is a magnetic head in which a magnetic head slider is fixed to a metal gimbal with an adhesive resin, a non-conductive adhesive resin is used for the main part of the adhesive resin, and a part thereof is silver. It is characterized by using a conductive paste such as a paste. By using a part of the conductive paste, conduction between the slider and the metal gimbal is ensured, and the gimbal is conducted to the housing of the disk drive through the metal suspension and grounded, so the slider is not charged.

  However, the above-described technique requires two steps, that is, an adhesive resin coating step and a conductive paste coating step, and there is a possibility that the adhesive strength of the coated surface of the conductive paste is weakened.

  The invention shown in Patent Document 2 is a conductive adhesive having a high adhesive strength, and exhibits conductivity and adhesiveness by using this adhesive. However, this adhesive is a heat curable resin and must be heated to be cured, and it was not fast cured without heating unlike an anaerobic curable adhesive.

  On the other hand, Patent Document 3 describes a method of obtaining conductive silicone by adding conductive powder or ionic liquid compound to silicone resin. This relates to a moisture curable silicone resin, which imparts conductivity by using a conductive powder and an ionic liquid compound in combination with a binder resin.

JP-A-2-61810 JP 11-323261 A Japanese Patent Laid-Open No. 2005-298661

  In order to solve the above-mentioned problems, it is conceivable to impart conductivity to the anaerobic curable composition. However, in order to impart conductivity to the anaerobic curable composition, a large amount of metal powder, carbon or the like must be added. However, the mechanism of anaerobic curing is achieved by coexisting a component that is intended to polymerize a radically polymerizable compound and a component that is intended to inhibit the polymerization of the radically polymerizable compound, thereby making the balance between the two components appropriate. Therefore, when a large amount of metal powder or carbon powder is added to impart conductivity, the storage stability of the anaerobic curable composition becomes extremely poor, and the storage stability as an industrial product cannot be achieved.

  In addition, it is possible to prevent gelation by adding a large amount of stabilizer or by freezing the storage environment, but the value as a product is low.

  The present invention overcomes the above-mentioned conventional problems. That is, the present invention relates to (a) a compound having at least one radical polymerizable functional group in the molecule, (b) an organic peroxide, (c) o-benzoixsulfimide, (d) an ionic liquid compound. : Anaerobic curable, comprising 1 to 40 parts by weight per 100 parts by weight of component (a), (e) conductive powder: 0.1 to 10 parts by weight per 100 parts by weight of component (a) A composition is provided.

  This invention expresses electroconductivity, without reducing the outstanding adhesiveness of an anaerobic curable composition. It also has excellent storage stability.

  The component (a) used in the present invention and the compound having at least one radical polymerizable functional group in the molecule are described below. First, examples of the radical polymerizable functional group include an acryloyl group, a methacryloyl group, a vinyl group, and a propenyl group. Such a compound having one functional group is generally called a radical polymerizable monomer, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl. (Meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, styrene, α-methylstyrene, Examples include divinylbenzene. (Meth) acrylic is a generic term for acrylic and methacrylic.

  A compound having two or more radical polymerizable functional groups, a so-called radical polymerizable polyfunctional monomer having two or more radical polymerizable functional groups in the molecule of a relatively low molecular compound, and a relatively high molecular compound And so-called radically polymerizable oligomers having radically polymerizable functional groups at both ends thereof. Radical polymerizable polyfunctional monomers include ethylene glycol diacrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetraacrylate, dipentaerythritol hexa (meth) acrylate, tetramethylol methane tetra ( And (meth) acrylate.

  As radically polymerizable oligomers, epoxy-modified (meth) acrylates, hydroxyl group-containing (meth) acrylates and terminal isocyanate group-containing compounds obtained by reacting acrylic acid, methacrylic acid or their multimers with epoxy groups of glycidyl ethers such as bisphenol And a urethane bond-containing (meth) acrylate obtained by reacting with a compound, a compound obtained by reacting a polyether resin with a (meth) acryloyl group, a compound obtained by reacting a polyester with a (meth) acryloyl group. .

  These may be used alone or for the purpose of adjusting the viscosity of the anaerobic curable composition or adjusting the properties of the cured product. Since it is difficult to remove, it is preferable to use a mixture of a radical polymerizable monomer and a radical polymerizable oligomer. In particular, a radical polymerizable oligomer selected from 2,2-bis [4- (methacryloxyethoxy) phenyl] propane and bisphenol A type epoxy acrylate, and a radical polymerization selected from 2-hydroxyethyl methacrylate and isobornyl acrylate. It is preferable to use a combination of functional monomers.

  The (b) organic peroxide used in the present invention is conventionally used in anaerobic curable compositions and is not particularly limited. For example, cumene hydroperoxide, t-butyl hydroperoxide , Hydroperoxides such as p-menthane hydroperoxide, diallyl peroxides such as dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, methyl ethyl ketone peroxide, cyclohexane peroxide, methylcyclohexane Ketone peroxides such as peroxides, diacyl peroxides such as benzoyl peroxide, lauroyl peroxide, acetyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyacetate, t-butyl Helper organic peroxide peroxy esters and the like such as oxybenzoate.

  These organic peroxides can be used alone or as a mixture of two or more. The amount of component (b) is usually 0.1 to 5 parts by weight per 100 parts by weight of component (a). If the amount is less than 0.1 parts by weight, the polymerization reaction may be insufficient. If the amount is more than 5 parts by weight, the stability of the anaerobic curable composition may be lowered.

The component (c) used in the present invention is o-benzoxlphimide, which is a component usually used for anaerobic curable compositions. o-Benzixurfimide is so-called saccharin, and the amount of component (c) is usually 0.1 to 5 parts by weight per 100 parts by weight of component (a).

  The component (d) used in the present invention is an ionic liquid compound. An ionic liquid is a salt that exists in a liquid state even at room temperature. Usually, “salt” is solid at room temperature like salt, but ionic liquid is liquid at room temperature. This is because when the ions constituting the salt are replaced with organic ions having a relatively large size, the melting point becomes low and the liquid ions are present even near room temperature.

  The ionic liquid compound is a salt as described above, and is a salt composed of a cation component and an anion component. Examples of the cation component include imidazolium, pyridinium, hyperidinium, pyrazonium, pyrrolidinium, pyrrolium, ammonium, and phosphonium. In addition, anionic components of ionic liquid compounds include halogen (chlorine, bromine, iodine, etc.), tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, bis (fluorosulfonyl) imide, bis (trifluorosulfonyl) imide, tri (tri Fluorosulfonyl) carboanion, trifluoroacetate, hydrofluoride anion, dicyanamide, tetrachloroferrate, ethyl sulfate, 2- (2-methoxyethoxy) ethyl sulfate, dimethyl phosphate, p-toluenesulfonate.

  Specific examples of the ionic liquid compound include 1-hexyl-3-methyl-imidazolium bromide salt, 1-hexyl-3-methyl-imidazolium chloride salt, 1-hexyl-3-methyl-imidazolium hexafluorophosphate salt, 1-hexyl-3-methyl-imidazolium tetrafluoroborate salt, 1-hexyl-3-methyl-imidazolium trifluoromethanesulfonate salt, 1-decyl-3-methyl-imidazolium bromide salt, 1-decyl-3-methyl -Imidazolium chloride salt, 1-butyl-pyridinium tetrafluoroborate salt, 1-hexyl-pyridium tetrafluoroborate salt, 1-hexyl-2,3-dimethyl-imidazolium tetrafluoroborate salt, 1-butyl-2,3 -Dimethyl -Imidazolium trifluoromethylsulfonate salt, 1-butyl-2,3-dimethyl-imidazolium bromide salt, 1-butyl-2,3-dimethyl-imidazolium chloride salt, 1-ethyl-2,3-dimethyl-imidazole Rium bromide salt, 1-ethyl-2,3-dimethyl-imidazolium chloride salt, 1-butyl-pyridinium bis (trifluoromethanesulfonyl) imide salt, N- (2-methoxyethyl) -N-methylpyrrolidinium tetrafluoro Borate, N- (2-methoxyethyl) -N-methylpyrrolidinium trifluoromethyl trifluoroborate, N- (2-methoxyethyl) -N-methylpyrrolidinium trifluoromethylpentafluoroethyl trifluoroborate, N , N-diethyl-N-methyl (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide salt, N, N-diethyl-N-methyl (2-methoxyethyl) ammonium tetrafluoroborate salt, 1-butyl-3-methylpyridinium trifluoromethanesulfonate salt , Etc.

  Among these, N, N-diethyl-N-methyl (2-methoxyethyl) ammonium bis (trifluoromethane) is particularly preferable as it is difficult to adversely affect storage stability and adhesiveness even when added to an anaerobic curable composition. Sulfonyl) imide salt, N, N-diethyl-N-methyl (2-methoxyethyl) ammonium tetrafluoroborate salt, and 1-butyl-3-methylpyridinium trifluoromethanesulfonate salt. These are preferable from the viewpoint of securing good adhesiveness. Component (d) is added in an amount of 1 to 40 parts by weight per 100 parts by weight of component (a). Preferably it is 10-40 weight part. When the amount is less than 1 part by weight, the conductivity is hardly expressed, and when it is more than 40 parts by weight, the adhesiveness of the anaerobic curable composition is lowered.

  Examples of the conductive powder (e) used in the present invention include particles of metals such as gold, silver, copper, nickel, palladium, indium, lead, and alloys thereof, carbon, and the like. Moreover, what formed the electroconductive layer by coat | covering a metal, ITO, etc. on the surface of cores, such as nonelectroconductive glass, a ceramic, a plastics, and a metal oxide. Examples of the shape of the powder include fine spheres, coarse spheres, and flakes.

  The component (e) used in the present invention is added in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the component (a). Preferably it is 1-10 weight part. Usually, even when 10 parts by weight of conductive powder is added to 100 parts by weight of the resin binder, conductivity is hardly exhibited. The conductivity due to the metal powder is expressed by the presence of the conductive powders in a binder state in the binder, but when the addition amount is small, the conductivity is interrupted and the conductivity is not expressed. In the present invention, the conductivity can be improved even in a small amount by combining with an ionic liquid compound. Therefore, conductivity can be imparted to the unstable anaerobic curable composition. When the amount is less than 0.1 parts by weight, sufficient conductivity cannot be obtained, and when the amount is more than 10 parts by weight, the storage stability of the anaerobic curable composition is lowered.

  Moreover, you may process the surface of such electroconductive powder with a silane compound. Examples of the silane compound include methyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, N- Examples include organoalkoxysilanes such as (2-aminoethyl) -3-aminopropyltrimethoxysilane; organohalosilanes such as methyltrichlorosilane and vinyltrichlorosilane; and organosilazanes such as hexamethyldisilazane.

  The composition of this invention can contain the component which accelerates | stimulates polymerization other than the said component. Examples of such components include amine compounds and mercaptan compounds in addition to o-benzoxlufimide. Amine compounds include heterocyclic secondary amines such as 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroquinaldine, and tertiary heterocyclic amines such as quinoline, methylquinoline, quinaldine and quinoxalinephenazine. Aromatic tertiary amines such as amine, N, N-dimethyl-anisidine, N, N-dimethylaniline, 1,2,4-triazole, oxazole, oxadiazole, thiadiazole, benzotriazole, hydroxybenzotriazole, benzo Examples thereof include azole compounds such as xazole, 1,2,3-benzothiadiazole, and 3-mercaptobenzotrizole, and hydrazine compounds such as acetylphenylhydrazine, benzophenone hydrazine, and adipic hydrazine. Examples of the mercaptan compound include, but are not limited to, linear mercaptans such as n-dodecyl mercaptan, ethyl mercaptan and butyl mercaptan. These components can be added in an amount of 0 to 2 parts by weight per 100 parts by weight of component (a).

  Various additives can be further added to the composition of the present invention. For example, in order to obtain storage stability, radical sorbents such as benzoquinone, hydroquinone, hydroquinone monomethyl ether, metal chelates such as ethylenediaminetetraacetic acid (EDTA) or its 2-sodium salt, oxalic acid, acetylacetone, o-aminophenol, etc. An agent or the like can also be added. These components can be added in an amount of 0 to 0.5 parts by weight per 100 parts by weight of component (a).

  Furthermore, in order to adjust the properties of the anaerobic curable resin and the properties of the cured product, a thickener, a filler, a plasticizer, a colorant, and the like can be used as necessary.

In the following, the present invention is proved to be superior in effect by examples. As Example 1, the following samples were prepared. (A) 2,2-bis [4- (methacryloxyethoxy) phenyl] propane 80 parts by weight, 2-hydroxyethyl methacrylate 20 parts by weight, (b) 1 part by weight of cumene hypertropoxide c) 1 part by weight of o-benzoixsulfimide as component, 0.3 parts by weight of acetylphenylhydrazine, 0.2 part by weight of 1,2,3,4-tetrahydroquinoline as additive, 0.02 EDTA · 2Na Further, 10 parts by weight of N, N-diethyl-N-methyl-N- (2methoxyethyl) ammonium bis (trifluorochloromethanesulfonyl) imide salt (manufactured by Nisshinbo Co., Ltd.) is used as component (d). 10 parts by weight of silver powder was added as part (e). Moreover, the other Example and the comparative example were similarly prepared by the compounding quantity described using the compound of Tables 1-4.
As the nickel powder, HCA-1 (manufactured by Nikko Rica), which is a scaly powder having an average particle size of 15 μm, was used. The silver powder was microspherical silver particles, and those manufactured by Mitsui Metal Mining Co., Ltd. having a primary particle size of 0.3 μm were used.

  The prepared samples were tested for anaerobic curability. As a test method, a test piece of material SPCC-SD (cold rolled steel plate), 100 mm × 25 mm (JIS G 3141) was used, and the curing time (set time) and the adhesive strength were measured. About 0.06 g of each sample was dropped on the test piece, the test pieces were stacked, and the time during which the sample stopped moving by hand was taken as the set time. Similarly, the end part 1 cm of the test piece was overlapped and allowed to stand for 24 hours, and then the tensile strength was measured.

  In addition, the storage stability of each sample was tested. As a test method, 80 ° C. gel time was measured. 5 g of an anaerobic composition was added to a glass test tube, and the time until gelation in an 80 ° C. atmosphere was measured. However, it was confirmed every 30 minutes, and the measurement was stopped when 3 hours passed. The measurement of 80 ° C. gel time is effective as a measure of storage stability, and if the liquid can be retained for 2 hours or more in this test, the stability can be maintained for about 6 months to 1 year at room temperature.

Furthermore, a conductivity test was performed. As a test method, comb electrode resistance measurement was performed. Each sample is coated on a copper plate arranged in a skewer shape at intervals of 100 μm, covered with a glass plate, wiped off the protruding part, further irradiated with ultraviolet rays (30 kJ / m ² ) to cure the sample, and resistance after curing The value was measured. In this test, since one side of the adherend is glass (non-metallic) and anaerobic curability is insufficient, 1 part of Irgacure 184, which is a photo-curing resin, is added to each sample, and UV curing is performed. Cured auxiliary.

Furthermore, the fitting resistance value was measured as follows. Preparation using a fitting test piece (iron 6 mm diameter × 40 mm pin and iron 15 mm diameter × 15 mm collar with a 6 mm inner diameter hole into which the pin can be inserted, and the clearance upon insertion is 1/100 mm). Each sample was applied to a pin and the pin was inserted into a collar. The protruding sample was removed and allowed to stand at 25 ° C. for 24 hours. Thereafter, an electrode was attached to each pin / collar, and the resistance value was measured.
These results are listed in Tables 1-4.
A resistance value indicated by “x” means that the resistance value measurement limit has been exceeded.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2007-247763 filed on Sep. 25, 2007, the contents of which are incorporated herein by reference.

  The anaerobic curable composition of the present invention is suitable for bonding at places where electrical conductivity is required. For example, bonding of housings of electric devices and electronic devices, bonding of head portions of hard disks, bonding of shaft portions of motors, etc. Is available.

Claims (3)

  (A) a compound having at least one radical polymerizable functional group in the molecule, (b) an organic peroxide, (c) o-benzoixsulfimide, (d) an ionic liquid compound: (a) component 100 An anaerobic curable composition comprising 1 to 40 parts by weight with respect to parts by weight, (e) conductive powder: 0.1 to 10 parts by weight with respect to 100 parts by weight of component (a).   The anaerobic curable composition of Claim 1 which contains a hydroxyl-containing (meth) acrylate as said (a) component.   As the component (d), N, N-diethyl-N-methyl (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide salt, N, N-diethyl-N-methyl (2-methoxyethyl) ammonium tetrafluoroborate An anaerobic curable composition according to claim 1 selected from a salt and 1-butyl-3-methylpyridinium trifluoromethanesulfonate salt.