Method for producing steel sheet laminate, steel sheet laminate, and adhesive composition

Abstract

The first objective of this invention is to provide a method for manufacturing a steel plate laminate that produces a steel plate laminate with excellent adhesion, wherein the curing speed of the adhesive is fast enough, the time required to complete the bonding and form the steel plate laminate is short, and the workability is good. The second objective of this invention is to manufacture a steel plate laminate with excellent adhesion. As a solution, a method for manufacturing a steel plate laminate is provided, which uses a free radical polymerizable adhesive composition to bond a steel plate coated with a primer containing a copper compound. The free radical polymerizable adhesive composition contains (A) a free radical polymerizable compound, (B) an organic peroxide, and (C) a phosphate ester compound having free radical polymerizable groups, wherein, relative to 100 parts by mass of (A) the free radical polymerizable compound, the amount of (C) the phosphate ester compound having free radical polymerizable groups is 0.055 parts by mass or more and less than 1 part by mass.

Description

Technical Field

[0001] This invention relates to a method for manufacturing steel plate laminates, steel plate laminates, and adhesive compositions thereof. Background Technology

[0002] Laminated steel sheets, especially laminated electromagnetic steel sheets, are used in the rotors or stators of motors in various equipment. Laminated steel sheets are typically stacked using riveting or welding. However, with the increasing use of thin-film laminates for the laminated electromagnetic steel sheets, it is necessary to address iron losses caused by stress concentration, strain concentration, and interlayer short circuits resulting from mechanical fastening. Against this backdrop, steel sheet laminate technology using insulating adhesives is gaining attention as a method to reduce iron losses by dispersing stress. Commonly used adhesives include epoxy resin adhesives and curing acrylic adhesives. Among these, curing acrylic adhesives are often used when room temperature curing is desired.

[0003] Patent document 1 describes a method for manufacturing a steel sheet laminate using a steel sheet coated with stamping oil containing copper soap as a curing accelerator and using an anaerobic adhesive (a type of curing acrylic adhesive).

[0004] Patent document 2 describes a method for fixing metal bolts / nuts by applying a curing accelerator pretreatment agent containing a chelating compound of copper, vanadium, chromium, manganese, iron, titanium, nickel or cobalt as an active ingredient, and then applying an anaerobic adhesive containing a (meth)acrylate compound.

[0005] Patent document 3 describes a method for fixing a metal bolt / nut by applying a curing accelerator for a (meth)acrylate curing composition containing a chelating compound of copper and / or vanadium to a metal bolt / nut, followed by applying an anaerobic adhesive containing a (meth)acrylate compound.

[0006] Patent document 4 describes an anaerobic adhesive composition comprising an anaerobic polymerizable acrylate monomer, an organic peroxide, and a phosphoric acid compound having a (meth)acryloyl group, which is applied to the inner wall of a ring and / or a shaft, and then the shaft is inserted into the ring for fitting and fixing.

[0007] Patent document 5 describes a polymeric adhesive composition containing a polymeric olefin unsaturated monomer compound, a phosphoric acid compound having at least one olefin unsaturated group, and an organic peroxide for use in bonding steel-to-steel and aluminum-to-aluminum materials.

[0008] Patent document 6 describes a free radical polymerizable adhesive composition for bonding steel plate laminates, comprising: (A) component: free radical polymerizable compound, (B) component: free radical polymerization initiator, and (C) component: phosphate ester compound having a group represented by the following formula (1) or (2).

[0009] -OP(O)(OH)-O- (1) -OP(O)(OH)2 (2) Patent documents Patent Document 1: Japanese Patent Application Publication No. 2006-334648 Patent Document 2: Japanese Patent Publication No. 49-021093 Patent Document 3: Japanese Patent Application Publication No. 60-179407 Patent Document 4: Japanese Patent Application Publication No. 51-132234 Patent Document 5: Japanese Patent Application Publication No. 54-141826 Patent Document 6: International Publication No. 2019 / 123885 Summary of the Invention Although the adhesive compositions described in Patent Documents 1 to 6 can produce steel plate laminates with excellent adhesion, the curing speed is not fast enough, which results in a long time required for the bonding to be completed and the steel plate laminates to be formed, thus making them less workable.

[0010] The problem to be solved by the present invention is to provide a method for manufacturing steel plate laminates, which can produce steel plate laminates with excellent adhesion, and the adhesive cures fast enough, so that the time required to complete the bonding and form the steel plate laminate is short and the workability is good.

[0011] Furthermore, another problem to be solved by the present invention is to provide an adhesive composition for steel plate laminates that can produce steel plate laminates with excellent adhesion, and the adhesive cures quickly enough to complete the bonding and form the steel plate laminate in a short time, and has good workability.

[0012] The inventors conducted in-depth research to solve the above-mentioned problems and found that the above-mentioned problems could be solved by using a method for manufacturing a steel plate laminate with a specific adhesive composition, the steel plate laminate obtained therefrom, and the specific adhesive composition, thereby completing the present invention.

[0013] Specifically, it is shown below.

[0014] [Item 1] A method for manufacturing a steel plate laminate, characterized in that a steel plate coated with a primer containing a copper compound is bonded using a free radical polymerizable adhesive composition, wherein the free radical polymerizable adhesive composition contains (A) a free radical polymerizable compound, (B) an organic peroxide and (C) a phosphate ester compound having free radical polymerizable groups, wherein, relative to 100 parts by mass of (A) the free radical polymerizable compound, the amount of (C) the phosphate ester compound having free radical polymerizable groups is 0.055 parts by mass or more and less than 1 part by mass.

[0015] [Item 2] A steel plate laminate, characterized in that it is a steel plate laminate manufactured by the method described in Item 1.

[0016] [Item 3] An adhesive composition for bonding a steel sheet laminate coated with a copper-containing primer, characterized in that... It contains (A) a free radical polymerizable compound, (B) an organic peroxide, and (C) a phosphate ester compound with a free radical polymerizable group. The amount of (C) phosphate ester compound having free radical polymerizable groups is more than 0.055 parts by mass and less than 1 part by mass relative to 100 parts by mass of (A) free radical polymerizable compound.

[0017] According to the present invention, a method for manufacturing a steel plate laminate is provided, which can produce a steel plate laminate with excellent adhesion, the adhesive curing speed is fast enough, the time required to complete the bonding and form the steel plate laminate is short, and the workability is good.

[0018] Furthermore, according to the present invention, an adhesive composition for steel plate laminates can be provided, which can produce steel plate laminates with excellent adhesion, the adhesive has a sufficiently fast curing speed, the time required to complete the bonding and form the steel plate laminate is short, and the workability is good.

[0019] The method for manufacturing steel plate laminates and the adhesive composition for steel plate laminates disclosed in this invention can simplify the manufacturing process of steel plate laminates, reduce iron loss of steel plate laminates, and contribute to the high performance and high reliability of motor rotors or stators. Therefore, it is extremely effective and applicable to a wide range of fields, and thus useful in industry.

[0020] The adhesive composition for steel sheet laminates of the present invention exhibits excellent adhesion to steel sheets with surfaces treated with stamping oil, especially electromagnetic steel sheets and cold-rolled steel sheets (SPCC-SD). It enables strong adhesion without removing the stamping oil applied to the steel sheets during the manufacturing process of the steel sheet laminate, which is of great industrial significance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a steel plate laminate manufacturing apparatus according to an embodiment of the present invention.

[0022] Symbol Explanation 1- Steel plate laminate manufacturing device; 2- Strip steel plate coil; 3- Strip steel plate; 4A- Primer coating device; 4B- Adhesive coating device; 5- Stamping forming device; 5A- Upper part of stamping forming device; 5B- Lower part of stamping forming device; 6A, 6B, 6C, 6D, 6E- Inner diameter / hole / groove punch heads; 7- Outer diameter punch head; 8- Steel plate laminate forming component receiving and holding part; 9- Steel plate laminate. Detailed Implementation

[0023] The following provides a detailed description of the manufacturing method of the steel plate laminate, the steel plate laminate, and the adhesive composition of the present invention.

[0024] In addition, in this specification, "(meth)acrylic acid" refers to "acrylic acid" and "methacrylic acid", "(meth)acrylate" refers to "acrylate" and "methacrylate", and "(meth)acryloyl" refers to "acryloyl" and "methacryloyl".

[0025] [Preparation method of steel plate laminate] The method for manufacturing the steel plate laminate of the present invention involves using a free radical polymerizable adhesive composition containing (A) a free radical polymerizable compound, (B) an organic peroxide, and (C) a phosphate ester compound having free radical polymerizable groups to bond a steel plate coated with a primer containing a copper compound. In the free radical polymerizable adhesive composition, relative to 100 parts by mass of (A) the free radical polymerizable compound, the amount of (C) the phosphate ester compound having free radical polymerizable groups is 0.055 parts by mass or more and less than 1 part by mass.

[0026] <Free radical polymerizable adhesive compositions> (A) Free radical polymerizable compounds) In the method for manufacturing the steel sheet laminate of the present invention, the free radical polymerizable compound (A) contained in the free radical polymerizable adhesive composition is selected from one or more free radical polymerizable monomers, free radical polymerizable oligomers, or free radical polymerizable polymers having free radical polymerizable functional groups, especially free radical polymerizable olefinic unsaturated groups. Furthermore, the free radical polymerizable compound (A) is a free radical polymerizable compound other than the phosphate ester compounds having free radical polymerizable groups described later in (C). Examples of free radical polymerizable functional groups include (meth)acryloyl, vinyl, allyl, and (meth)acrylamido, among which (meth)acryloyl is preferred.

[0027] Regarding (A) free radical polymerizable compounds, from the perspective of adhesion to steel sheets, especially electromagnetic steel sheets, on which stamping oil (stamping oil) components have been applied to the surface, it is preferable to use one or more free radical polymerizable oligomers and / or free radical polymerizable polymers. Furthermore, from the perspective of achieving superior adhesion to steel sheets such as cold-rolled steel sheets or electromagnetic steel sheets, adjusting the viscosity of the adhesive composition for excellent workability, and preventing adhesive overflow during steel sheet bonding, it is preferable to use one or more free radical polymerizable oligomers and / or free radical polymerizable polymers in combination with one or more free radical polymerizable monomers.

[0028] {Free radical polymerizable oligomers and / or free radical polymers} As a free radical polymerizable oligomer and / or free radical polymer, examples include one or more selected from urethane (meth)acrylates, epoxy (meth)acrylates, bisphenol epoxy alkyl adduct (meth)acrylates, ether (meth)acrylates, ester (meth)acrylates, isoprene (meth)acrylates, hydrogenated isoprene (meth)acrylates, acrylic polymers containing (meth)acryloyl groups, and polyisobutylene containing (meth)acryloyl groups. Among these, one or more selected from urethane (meth)acrylates, epoxy (meth)acrylates, bisphenol epoxy alkyl adduct (meth)acrylates, and ether (meth)acrylates are preferred from the perspectives of excellent adhesion to cold-rolled steel sheets and / or electromagnetic steel sheets and a high glass transition temperature of the cured product.

[0029] Carbamate (meth)acrylates can be obtained by reacting at least a polyol component, a polyisocyanate component, with a compound having a (meth)acrylate group.

[0030] As a polyol component, for example, a component containing one or more polymeric polyols selected from (hydrogenated) butadiene polyols, polycarbonate polyols, polyether polyols, polyester polyols, polyacrylate polyols (acrylic polyols), polyurethane polyols, etc., may be used.

[0031] As a polyisocyanate component, one or more of the following can be used: aliphatic polyisocyanates (such as hexamethylene diisocyanate), alicyclic polyisocyanates (such as dicyclohexylmethane diisocyanate and isobornyl diisocyanate), aromatic polyisocyanates (such as toluene diisocyanate and diphenylmethane diisocyanate), and aromatic aliphatic polyisocyanates (such as phenyldimethyl diisocyanate).

[0032] As a compound having a (meth)acrylate group, one or more of the following can be used, for example, compounds containing a (meth)acrylate group that have a group that reacts with an isocyanate group ((meth)acrylate hydroxyalkyl ester, acrylic acid, etc.), or compounds containing an isocyanate group and containing a (meth)acrylate group.

[0033] Examples of urethane (meth)acrylates include, for example, one or more selected from the following: urethane (meth)acrylates having a (hydrogenated) polybutadiene backbone, urethane (meth)acrylates having a polycarbonate backbone, urethane (meth)acrylates having a polyether backbone, urethane (meth)acrylates having a polyester backbone, urethane (meth)acrylates having a polyacrylate backbone, urethane (meth)acrylates having a polyurethane backbone, urethane (meth)acrylates having a castor oil backbone, etc.

[0034] Epoxy (meth)acrylates are obtained by reacting epoxy resins with (meth)acrylate compounds having functional groups that can react with epoxy groups.

[0035] Examples of epoxy resins include one or more selected from bisphenol type epoxy resins (bisphenol A type epoxy resin, bisphenol F type epoxy resin, etc.), phenolic varnish type epoxy resins, and epoxy resins with terminal glycidyl ethers of alkyl oxy groups of bisphenol type epoxy resins.

[0036] As a (meth)acrylate compound having a functional group that reacts with an epoxy group, one or more of the following can be listed, for example, (meth)acrylate compounds having a carboxyl group such as (meth)acrylic acid, and (meth)acrylate compounds having a hydroxyl group such as hydroxyethyl (meth)acrylate.

[0037] As an epoxy (meth)acrylate, commercially available products can be used. For example, one or more of the following can be listed: DICLITE (registered trademark) UE-8071-60BH, UE-8740, UE-8410 (the above, manufactured by DIC Corporation), KAYARD R-115F (manufactured by Nippon Kayaku Co., Ltd.), HITALOID 7851 (manufactured by Showa Denko Co., Ltd.), Epoxy Ester 3000MK, 3000A (manufactured by Kyoeisha Chemical Co., Ltd.), VISCOAT V#540 (manufactured by Osaka Organic Chemical Co., Ltd.), EBECRYL 600, EBECRYL 3700 (manufactured by DAICEL-ALLNEX Co., Ltd.).

[0038] As bisphenol alkyl oxide adducts (meth)acrylates, one or more compounds represented by the following formula (A) can be listed, for example; [Chemistry 1]

[0039] (In formula (A), R 11 It can be a hydrogen atom or a methyl group.

[0040] R 12 It can be a hydrogen atom or a methyl group.

[0041] A 1 It is an alkylene group having 1 to 6 carbon atoms, and when multiple alkylene groups exist, they can be different from each other.

[0042] A 2 It is an alkylene group having 1 to 6 carbon atoms, and when multiple alkylene groups exist, they can be different from each other.

[0043] X is any one of the following: directly bonded, -CH2-, -C(CH3)2-, -CH(CH3)-, -O-, -S-, -SO2-, -CO-, -CF2-, -C(CF3)2-, -C(Ph)2-, -CH(Ph)- (Ph is phenyl).

[0044] m is an integer greater than or equal to 0 or 1.

[0045] n is an integer greater than or equal to 0 or 1.

[0046] For example, one or more of the following can be listed: (poly)ethoxy-modified bisphenol A di(meth)acrylate, (poly)propoxy-modified bisphenol A di(meth)acrylate, etc.

[0047] Among these, (poly)ethoxylated modified bisphenol A di(meth)acrylate is preferred, and among the compounds represented by formula (A) above, R is particularly preferred. 11 R is a hydrogen atom or a methyl group. 12 A is a hydrogen atom or a methyl group. 1 and A 2 It is a compound that is a 2-carbon alkylene group, X is -C(CH3)2-, and m+n (i.e., ethoxy equivalent) is 1 to 40 (preferably 2 to 10).

[0048] {Free radical polymerizable monomers} A free radical polymerizable monomer is a compound having one or more free radical polymerizable groups within its molecule, and is not an oligomer or polymer. Furthermore, it is not particularly limited as long as it is a free radical polymerizable compound other than a phosphate ester compound having a free radical polymerizable group (C). For example, one or more types selected from monofunctional monomers, polyfunctional monomers, etc. can be listed.

[0049] Among these, from the perspective of forming a free radical polymerizable adhesive composition for steel sheet laminates that can form a cured product with a high glass transition point and superior adhesion to steel sheets such as cold-rolled steel sheets and electromagnetic steel sheets, it is preferable to include monofunctional monomers having functional groups such as hydroxyl, carboxyl, amino, and glycidyl groups.

[0050] As a monofunctional monomer, examples include one or more selected from the following: methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, lauryl methacrylate, stearyl methacrylate, tetrahydrofurfuryl methacrylate, caprolactone-modified tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, dicyclopentyl methacrylate, isobornyl methacrylate, benzyl methacrylate, phenyl methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl methacrylate, nonylphenoxytetraethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, and butoxyethyl methacrylate. Butoxytriethylene glycol (meth)acrylate, 2-ethylhexyl polyethylene glycol (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, glyceryl methacrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, modified butyl methacrylate, epichlorohydrin modified phenoxy (meth)acrylate, ethylene oxide modified phthalic acid (meth)acrylate, ethylene oxide modified succinic acid (meth)acrylate, caprolactone modified 2-hydroxyethyl (meth)acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, morpholino methacrylate, etc. Among these, from the perspective of superior adhesion to cold-rolled steel sheets and / or electromagnetic steel sheets or rapid curing properties (short initial curing time), one or more of the following are preferred: dicyclopentyl methacrylate, isobornyl methacrylate, benzyl methacrylate, phenyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate.

[0051] As a multifunctional monomer, for example, one or more of the following can be listed: 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ethylene oxide modified neopentyl glycol di(meth)acrylate, propylene oxide modified neopentyl glycol di(meth)acrylate, hydroxypentyl ester neopentyl glycol diacrylate, caprolactone modified hydroxypentyl ester neopentyl glycol diacrylate, neopentyl glycol modified trimethylolpropane di(meth)acrylate, stearic acid modified pentaerythritol di(meth)acrylate, dicyclopentenyl di(meth)acrylate, ethylene oxide modified Dicyclopentenyl di(meth)acrylate, di(meth)acryloyl isocyanurate, dimethyloltricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene oxide modified trimethylolpropane tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, epichlorohydrin modified trimethylolpropane tri(meth)acrylate, epichlorohydrin modified tri(meth)acrylate glyceryl tri(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, bis(trimethylolpropane)tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, alkyl modified dipentaerythritol pentaacrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. Among these, from the perspective of superior adhesion to cold-rolled steel sheets and / or electromagnetic steel sheets or rapid curing properties (short initial curing time), it is preferable to use one or more selected from dicyclopentenyl di(meth)acrylate, ethylene oxide modified dicyclopentenyl di(meth)acrylate, di(meth)acryloyl isocyanurate, dimethyloltricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tri(acryloyloxyethyl) isocyanurate, bis(trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, etc.

[0052] Regarding the amount of (A) free radical polymerizable compound, the total amount of the free radical polymerizable adhesive composition is set to 100% by mass, for example, 90% by mass or more, preferably 95% by mass or more, for example, 99% by mass or less, preferably 98% by mass or less.

[0053] (B) Organic peroxides The (B) organic peroxide contained in the free radical polymerizable adhesive composition used in the preparation of the steel plate laminate of the present invention is a substance used to impart anaerobic curing and / or heat curing properties to the free radical polymerizable adhesive composition.

[0054] As for (B) organic peroxides, examples include one or more selected from the following: cumene hydroperoxide, tert-butyl hydroperoxide, p-menthol hydroperoxide, methyl ethyl ketone peroxide, cyclohexane peroxide, dicumene peroxide, dicumene hydroperoxide, etc., as well as ketone peroxides, diallyl peroxides, ester peroxides, etc. Among these, hydroperoxides are preferred from the perspective of superior reactivity and storage stability of free radical polymerizable adhesive compositions for bonding steel sheet laminates.

[0055] As for (B) organic peroxides, from the perspective of excellent anaerobic curing properties, organic peroxides with a 1-hour half-life temperature of 80°C or higher are preferred, more preferably 100°C or higher, less preferably 300°C or lower, and more preferably less than 200°C. The 1-hour half-life temperature refers to the value measured under the condition of thermal decomposition in benzene at a concentration of 0.1 mol / L.

[0056] Organic peroxides with a half-life of 1 hour and a temperature in the range of 80°C to 300°C can be exemplified by hydroperoxides. Specific examples of hydroperoxides include one or more selected from p-menthol hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, isopropylbenzene hydroperoxide, tert-butyl hydroperoxide, etc.

[0057] The amount of (B) organic peroxide relative to 100 parts by mass of (A) free radical polymerizable compound is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, for example, 10 parts by mass or less, preferably 5 parts by mass or less. By setting the amount of (B) organic peroxide relative to 100 parts by mass of (A) free radical polymerizable compound to a range of 0.05 parts by mass or more and 10 parts by mass, the adhesive strength of the free radical polymerizable adhesive composition can be improved.

[0058] (C) Phosphate ester compounds with free radical polymerizable groups) The phosphate ester compound (C) containing free radical polymerizable groups in the free radical polymerizable adhesive composition used in the preparation of the steel plate laminate of the present invention is one or more of a phosphate ester compound having free radical polymerizable functional groups and groups represented by the following formula (1) or (2).

[0059] -OP(O)(OH)-O- (1) -OP(O)(OH)2 (2) By combining (A) a free radical polymerizable compound and (B) an organic peroxide, a free radical polymerizable adhesive composition for steel sheet laminates that exhibits adhesion to steel sheets with surfaces covered by stamping oil (stamping oil) can be obtained with significant effect.

[0060] As (C) a phosphate ester compound having a free radical polymerizable group, there is no particular limitation, for example, one or more may be selected from 2-hydroxymethyl (meth) acrylate acid phosphate, 2-hydroxyethyl (meth) acrylate acid phosphate, 2-hydroxypropyl (meth) acrylate acid phosphate, ethylene oxide modified di(meth) acrylate phosphate, ethylene oxide modified tri(meth) acrylate phosphate, and caprolactone modified ethylene oxide modified di(meth) acrylate phosphate.

[0061] (C) Phosphate ester compounds having free radical polymerizable groups, which can be synthesized or commercially available products can be used. Commercially available products include, for example, one or more selected from Light ester PA, P-1M, P-2M (all manufactured by Kyoeisha Chemical Co., Ltd.), KAYAMERPM-1 (manufactured by Nippon Kayaku Co., Ltd.), JPA-514 (manufactured by Johoku Chemical Co., Ltd.).

[0062] Relative to 100 parts by mass of the free radical polymerizable compound (A), the amount of the phosphate ester compound (C) having a free radical polymerizable group is 0.055 parts by mass or more and less than 1 part by mass. Preferably, it is 0.06 parts by mass or more, more preferably 0.065 parts by mass or more, even more preferably 0.07 parts by mass or more, preferably 0.8 parts by mass or less, and more preferably 0.7 parts by mass or less.

[0063] Compared to 100 parts by mass of (A) the free radical polymerizable compound, by setting the amount of (C) the phosphate ester compound having free radical polymerizable groups to 0.055 parts by mass or more and less than 1 part by mass, the adhesion strength (tensile shear bond strength based on Japanese Industrial Standard JIS K 6850 (1999)) to the steel plate is superior to 2.0 N / mm. 2 Furthermore, the initial curing time (the initial curing time specified in the embodiment) can be set to less than 300 seconds, preferably less than 250 seconds, and more preferably less than 180 seconds.

[0064] Regarding the amount of phosphate ester compounds with free radical polymerizable groups (C), when it is more than 1 part by mass, although the tensile shear bond strength is high and the adhesion is excellent, there is a risk of long initial curing time and slow curing speed. When it is less than 0.055 parts by mass, although the initial curing time is short and the curing speed is fast, there is a risk of low tensile shear bond strength and poor adhesion.

[0065] (D) Anaerobic solidification catalyst) The free radical polymerizable adhesive composition used in the method for manufacturing the steel plate laminate of the present invention preferably further contains (D) an anaerobic curing catalyst.

[0066] As the (D) anaerobic curing catalyst, one or more can be selected from imide compounds, amine compounds, azole compounds, thiols, hydrazine compounds, etc. Among these, imide compounds are preferred from the perspective of improving anaerobic curing properties.

[0067] The imide compound is one or more compounds having a group represented by the following formula (3) or (4) or a salt thereof.

[0068] -CONHCO- (3) -CONHSO2- (4) As an imide compound, examples include one or more selected from o-benzoylsulfonylimide (saccharin), succinimide, phthalimide or its salts (especially alkali metal salts such as sodium and potassium salts).

[0069] As amine compounds, examples include one or more heterocyclic secondary amines selected from 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroquinalidine, etc.; heterocyclic tertiary amines selected from quinoline, methylquinoline, quinalidine, quinoxaline, phenazine, etc.; and aromatic tertiary amines selected from N,N-dimethyl-methoxyaniline, N,N-dimethylaniline, etc.

[0070] As azole compounds, examples include one or more selected from 1,2,4-triazole, oxazole, oxadiazole, thiadiazole, benzotriazole, hydroxybenzotriazole, benzoxazole, 1,2,3-benzothiadiazole, 3-mercaptobenzotriazole, etc.

[0071] As a thiol compound, one or more straight-chain thiols such as n-dodecyl thiol, ethanethiol, and butanethiol can be listed as examples.

[0072] Examples of hydrazine compounds include, for example, one or more of the following: 1-acetyl-2-phenylhydrazine, 1-acetyl-2-(p-tolyl)hydrazine, 1-benzoyl-2-phenylhydrazine, 1-(1',1',1'-trifluoro)acetyl-2-phenylhydrazine, 1,5-diphenylcarbazine, 1-formyl-2-phenylhydrazine, 1-acetyl-2-(p-bromophenyl)hydrazine, 1-acetyl-2-(p-nitrophenyl)hydrazine, 1-acetyl-2-(p-methoxyphenyl)hydrazine, 1-acetyl-2-(2'-phenylethylhydrazine), p-nitrophenylhydrazine, p-trisulfonylhydrazine, 1-acetyl-2-methylhydrazine, 1-phenylhexacarbazine, tert-butyl 2-phenylhydrazine formate, di(phenylhydrazine) succinate, etc.

[0073] Regarding the amount of (D) anaerobic curing catalyst, there are no particular limitations as long as it does not impair the processability, bond strength, rapid curing, and storage stability of the free radical polymerizable adhesive composition. The amount is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, for example, 5 parts by mass or less, and preferably 3 parts by mass or less, relative to 100 parts by mass of (A) free radical polymerizable compound. By setting the amount of (D) anaerobic curing catalyst to a range of 0.1 parts by mass or more and 5 parts by mass or less relative to 100 parts by mass of (A) free radical polymerizable compound, the anaerobic curing properties and storage stability of the free radical polymerizable adhesive composition can be improved.

[0074] (E) Preservative stabilizer) The free radical polymerizable adhesive composition used in the method for manufacturing the steel sheet laminate of the present invention preferably further contains (E) a preservation stabilizer. Examples of preservation stabilizers include one or more selected from polymerization inhibitors (free radical scavengers, metal chelators), antioxidants, etc.

[0075] As polymerization inhibitors, examples include one or more metal chelating agents selected from ethylenediaminetetraacetic acid, its disodium salt, its tetrasodium salt, oxalic acid, acetylacetone, and o-aminophenol; one or more quinone compounds selected from hydroquinone, benzoquinone, hydroquinone monomethyl ether, β-naphthoquinone, 2-methoxy-1,4-naphthoquinone, methylhydroquinone, monotert-butylhydroquinone, 2,5-ditert-butylhydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, and 2,5-ditert-butyl-p-benzoquinone; and pentaerythritol tetra(3-(3,5-ditert-butyl-4-hydroxyphenyl)propionic acid. One or more hindered phenolic compounds selected from esters, 2,6-di-tert-butyl-4-methylphenol, 2,2-methylenebis(4-methyl-6-tert-butylphenol); hindered amine compounds; one or more nitrosamine compounds selected from N-methyl-N-nitrosoaniline, N-nitrosodiphenylamine, N-nitrosophenylhydroxylamine aluminum salt; phosphorus compounds such as triphenyl phosphite; one or more selected from phenothiazine, N-isopropyl-N'-phenyl-p-phenylenediamine, diethylhydroxylamine, sulfur, 4-tert-butylcatechol, potassium triiodide; etc.

[0076] (E) There is no particular limitation on the amount of the preservation stabilizer. It may be set to 7 parts by mass or less, for example, relative to 100 parts by mass of the free radical polymerizable compound (A), and preferably to be 0.001 parts by mass or more or 5 parts by mass.

[0077] (F) Other ingredients) The free radical polymerizable adhesive composition used in the method for manufacturing the steel plate laminate of the present invention may contain (F) other components, in addition to (A) free radical polymerizable compounds, (B) organic peroxides, (C) phosphate ester compounds having free radical polymerizable groups, (D) anaerobic curing catalysts and (E) preservation stabilizers, within the scope of not impairing the function of the adhesive composition such as curability or the adhesion of the cured product.

[0078] As other components in (F), for example, one or more may be selected from organic fillers (elastomers, thermoplastic resins, thermosetting resins, etc.), inorganic fillers, silane coupling agents, curing speed regulators, plasticizers, defoamers, heavy metal passivators, adhesives and / or adhesion promoters (tackifiers), antioxidants, light stabilizers, reinforcing agents, colorants, flame retardants, rust inhibitors, dispersants, thixotropic agents, anti-settling agents, anti-aging agents, light stabilizers, ultraviolet absorbers, fragrances, etc.

[0079] As an organic filler, one or more of the following can be selected: polyethylene, polypropylene, polyamide, cross-linked acrylic acid, cross-linked polystyrene, polyester, polyvinyl alcohol, polyvinyl butyral, polycarbonate, epoxy resin, various rubbers, elastomers (diene rubbers, olefin elastomers, urethane elastomers, silicone elastomers, etc.).

[0080] As an inorganic filler, one or more of the following can be selected: glass, silicon dioxide, alumina, mica, ceramics, calcium carbonate, aluminum nitride, carbon powder, kaolin, dried clay minerals, dried diatomaceous earth, etc.

[0081] Silane coupling agents are used as binding agents. Examples of silane coupling agents include γ-chloropropyltrimethoxysilane, octenyltrimethoxysilane, epoxypropoxyoctyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, γ-epoxypropoxypropyltriethoxysilane, γ-epoxypropoxypropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, and N-2-(aminoethyl)silane. One or more of the following: -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-isocyanate-propyltriethoxysilane, γ-ureopropyltriethoxysilane, p-styryltrimethoxysilane, etc.

[0082] (Properties of free radical polymerizable adhesive compositions or their cured products, etc.) {Tensile shear bond strength} The tensile shear bond strength of the free radical polymerizable adhesive composition of the present invention is, for example, 2.0 N / mm. 2 The preferred value is 3.0 N / mm. 2 The tensile shear bond strength can be obtained by the method described in the examples below.

[0083] {Initial Consolidation Time} The initial curing time of the free radical polymerizable adhesive composition of the present invention is, for example, less than 300 seconds, preferably less than 250 seconds, and more preferably less than 180 seconds. The initial curing time can be obtained by the method described in the examples below.

[0084] {glass transition point} The glass transition point of the cured product of the free radical polymerizable adhesive composition of the present invention, from the perspective of heat resistance of the steel plate laminate, is, for example, 60°C or higher, preferably 70°C or higher.

[0085] The glass transition point can be determined, for example, by the following method.

[0086] A substance obtained by adding 0.3 parts by weight of the following primer to 100 parts by weight of the free radical polymerizable adhesive composition is injected between two PET films spaced 1 mm apart to produce a cured product.

[0087] Samples measuring 10 mm wide and 40 mm long were cut from the obtained cured material. The glass transition point was measured using a Seiko Instruments DMS6100 in tensile mode at a temperature range of 25°C to 350°C, a heating rate of 5°C / min, and a frequency of 1 Hz. The peak value of tanδ was determined and taken as the glass transition point.

[0088] {Viscosity} The viscosity of the free radical polymerizable adhesive composition used in the manufacturing method of the steel plate laminate of the present invention is not particularly limited. From the perspective of processability or preventing overflow during bonding, it can be set to, for example, 0.01 Pa. For values ​​above s, a preferred setting is 0.05 Pa. s or more, preferably 0.5 Pa Above s, for example, it can be set to 50Pa. For values ​​below s, a Pa value of 30 Pa is preferred. Below s, it is more preferable to set it to 15 Pa. Below s.

[0089] Viscosity can be adjusted using methods known in the adhesive field, such as the formulation of viscosity modifiers (thixotropic agents).

[0090] Viscosity can be measured as follows: 100g of free radical polymerizable adhesive composition is placed in a bottle, poured into a measuring cup, and measured using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25°C and a rotation speed of 60 rpm.

[0091] (Method for manufacturing adhesive composition) The method for manufacturing the free radical polymerizable adhesive composition used in the method for manufacturing the steel plate laminate of the present invention is not particularly limited. For example, it can be manufactured by adding at least a specified amount of (A) a free radical polymerizable compound, (B) an organic peroxide and (C) a phosphate ester compound having free radical polymerizable groups to a mixing container in any order and mixing them.

[0092] When mixing, various mixing devices can be used, such as mixers (rotation / revolution mixers, planetary mixers, etc.), drum mixers, agitators, stirrers, mechanical homogenizers, ultrasonic homogenizers, high-pressure homogenizers, shakers, V-type mixers, and Nota mixers. Mixers are preferred.

[0093] There are no particular limitations on the mixing conditions. The temperature condition can be set to 0°C or higher, preferably 10°C or higher, and for example, 100°C or lower, more preferably 70°C or lower. The mixing time can be set to 1 minute or more, preferably 5 minutes or more, and for example, 10 hours or less, preferably 5 hours or less.

[0094] <Primers containing copper compounds> The primer used in the manufacturing method of the steel plate laminate of the present invention contains a copper compound.

[0095] In addition to copper compounds, primers may also contain oils, solvents, rust inhibitors, corrosion inhibitors, etc.

[0096] As copper compounds, examples include copper salts of carboxylic acids such as copper neodecanoate, copper 2-ethylhexanoate, copper naphthenate, copper octenate, copper hexanoate, copper propionate, and copper 2,4-pentanedione (copper acetylacetone); copper complexes such as copper ethylenediamine and copper propylenediamine; and more than one of the following.

[0097] As the oil, stamping oil, mineral oil, synthetic oil, animal and vegetable oils, etc., can be used. In this invention, since the process of stamping steel sheets into arbitrary shapes and the process of stacking the stamped steel sheets to form a steel sheet laminate are performed continuously, it is preferable that the primer contains stamping oil. By containing stamping oil, the occurrence of seizing or sticking can be prevented during various processing of the steel sheets.

[0098] As a solvent, one or more organic solvents and / or water may be listed. There are no particular limitations on the organic solvent. For example, one or more selected from the following may be listed: aliphatic hydrocarbon organic solvents with 5 to 40 carbon atoms (hexane, heptane, paraffin, etc.); alicyclic hydrocarbon solvents with 5 to 20 carbon atoms; aromatic hydrocarbon solvents with 6 to 20 carbon atoms (benzene, toluene, xylene, ethylbenzene, indene, etc.); alcohol solvents with 1 to 10 carbon atoms (methanol, ethanol, propanol, isopropanol, hexanol, etc.); ketone solvents with 3 to 20 carbon atoms (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.); ether solvents with 2 to 20 carbon atoms (tetrahydrofuran, diethyl ether, dioxane, ethyl cellosolve, propylene glycol monomethyl ether, etc.); ester solvents with 2 to 20 carbon atoms (methyl acetate, ethyl acetate, butyl acetate, etc.), etc.

[0099] The composition of the primer is not particularly limited. When the total amount of the primer is set to 100% by mass, the copper compound is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 8.0% by mass or less. Furthermore, when the total amount of the primer is set to 100% by mass, the oil is, for example, 20.0% by mass or more, preferably 25.0% by mass or more, more preferably 30.0% by mass or more, for example, 80.0% by mass or less, preferably 70.0% by mass or less, more preferably 60.0% by mass or less. Additionally, the solvent is used in an amount equal to 100% by mass.

[0100] <Steel Plate> The steel sheet used in the manufacturing method of the steel sheet laminate of the present invention is not particularly limited. Various steel sheets can be used depending on the application. In the present invention, steel sheets that are circulating in a rolled state can be used directly without degreasing treatment.

[0101] Various types of iron steel plates can be listed as examples of steel plates. Among them, cold-rolled steel plates and electromagnetic steel plates are preferred. In this invention, with regard to electromagnetic steel plates, steel plates that are mainly used in components such as rotors or stators of motors due to their electromagnetic properties are preferred.

[0102] The thickness of the steel plate is not particularly limited and can be appropriately specified according to the application. For example, it is 0.01 mm or more, preferably 0.1 mm or more, for example, 5 mm or less, preferably 3 mm or less, and more preferably 1 mm or less. In addition, the thickness of the cured product of the free radical polymerizable adhesive composition layer in the steel plate laminate is not particularly limited.

[0103] The shape of the stacked steel plates is not particularly limited. In this invention, it is preferable to stack steel plates coated with a free radical polymerizable adhesive composition and a primer, which are stamped into a predetermined shape, to form a steel plate laminate. In particular, two or more, preferably five or more, of the stamped strip electromagnetic steel plates can be stacked to form an electromagnetic steel plate laminate.

[0104] (Manufacturing apparatus for steel plate laminates) Figure 1 An embodiment of a steel plate laminate manufacturing apparatus used in the method for manufacturing the steel plate laminate according to the present invention is shown.

[0105] exist Figure 1 In the steel plate laminate manufacturing apparatus 1, a strip steel plate 3 is drawn from a strip steel plate coil 2. A primer containing stamping oil is applied to one surface of the strip steel plate 3 using a primer coating device 4A, and an adhesive is applied to the other surface using an adhesive coating device 4B. After coating, the strip steel plate 3 is fed into a stamping forming apparatus 5. In the stamping forming apparatus 5, punching heads 6A, 6B, 6C, 6D, and 6E can be provided as needed to perform one or more punching processes such as inner diameter, hole, and slot on the strip steel plate 3. Furthermore, the order of the inner diameter, hole, and slot punching processes is not particularly limited. After the inner diameter, hole, and slot punching processes, the strip steel plate 3 is punched out into a steel plate laminate forming component in the stamping forming apparatus 5 by an outer diameter punching head 7. The punched steel plate laminate forming components are housed in the steel plate laminate forming component housing and holding part 8. The primer layer and the adhesive layer are in contact, so that the steel plate laminate forming components are bonded together in sequence. After a specified number of laminates are bonded together, a steel plate laminate 9 is formed.

[0106] The resulting steel plate laminate 9 is removed from the steel plate laminate forming component receiving and holding part 8. Heating can be performed using a constant temperature bath, far-infrared heater, or similar equipment to achieve more thorough curing of the adhesive. For example, the heating conditions can be set to a temperature of 40°C to 300°C and a time of 10 minutes to 5 hours.

[0107] exist Figure 1 In the steel plate laminate manufacturing apparatus 1, the primer and adhesive are simultaneously applied to the strip steel plate 3 by the primer coating device 4A and the adhesive coating device 4B. The adhesive coating device 4B can be set on the upstream side of the outer diameter punching head 7 (any position before the outer diameter punching process).

[0108] exist Figure 1 In the steel plate laminate manufacturing apparatus 1, in order to prevent the primer and / or free radical polymerizable adhesive composition coated on the surface of the strip steel plate 3 from adhering, surface treatment (anti-adhesion treatment) can be performed on the surfaces of each punch 6A, 6B, 6C, 6D, 6E, 7 used for punching the strip steel plate 3, or on the surfaces of components constituting the conveyor line of the strip steel plate 3.

[0109] In the steel plate laminate manufacturing apparatus 1, in order to improve the workability of the blanking process and prevent biting or sticking, it is preferable to use a primer containing stamping oil (stamping oil).

[0110] exist Figure 1 In the steel plate laminate manufacturing apparatus 1 shown, punches 6A, 6B, 6C, 6D, and 6E are provided as punching heads for inner diameters, holes, slots, etc., but punching heads can be added or removed as needed. For example, to improve punching accuracy, the number of punching heads can be increased.

[0111] exist Figure 1 In the steel plate laminate manufacturing apparatus 1 shown, the positions of the primer coating device 4A and the adhesive coating device 4B are not particularly limited. The primer coating device 4A may also be positioned below the strip steel plate 3.

[0112] exist Figure 1 In the steel plate laminate manufacturing apparatus 1 shown, there are no particular limitations on the coating methods in the primer coating apparatus 4A and the adhesive coating apparatus 4B. For example, one or more coating methods selected from roller coating, dispensing coating, spray coating, inkjet coating, dip coating, brush coating, etc. can be listed.

[0113] exist Figure 1 In the steel plate laminate manufacturing apparatus 1 shown, instead of pulling out the strip steel plate 3 from the strip steel plate coil 2, a steel plate pre-formed into a specified shape can be continuously supplied to manufacture a steel plate laminate.

[0114] [Laminated steel plate assembly] The steel plate laminate of the present invention is obtained by [the method of manufacturing steel plate laminate].

[0115] In this invention, an electromagnetic steel sheet coated with a primer containing a copper compound and a free radical polymerizable adhesive composition is preferably used to construct the steel sheet laminate. Furthermore, in this invention, an electromagnetic steel sheet that has been punched into a predetermined shape from a strip of steel sheet is preferably used to construct the steel sheet laminate.

[0116] The thickness of the steel plate used in the steel plate laminate is not particularly limited. From the perspective of the need for thinner steel plate laminates due to the miniaturization of motors and the like, the thickness is preferably 0.01 mm or more, preferably 0.1 mm or more, preferably 3.0 mm or less, and preferably 1.0 mm or less.

[0117] The thickness of the adhesive layer (cured product of the free radical polymerizable adhesive composition) constituting the steel plate laminate is not particularly limited. For example, it is 0.1 μm or more, preferably 0.5 μm or more, for example 1000 μm or less, preferably 500 μm or less.

[0118] There is no particular limitation on the number of steel plates stacked. For example, it can be 2 or more, preferably 3 or more, for example 5000 or less, for example 3000 or less, for example 1000 or less, and also for example 800 or less.

[0119] In the steel plate laminate of the present invention, especially in the steel plate laminate using electromagnetic steel plates, the adhesive cured layer not only functions as an insulating layer, but also as a buffer layer for steel plate stress.

[0120] When the steel plate laminate of the present invention is used in the rotor, stator, etc. of an electric motor, current loss, stress concentration, and stress strain can be reduced, thus forming a high-efficiency, high-performance, and high-reliability electric motor.

[0121] Motors using the steel plate laminate of the present invention as the core of the rotor and / or stator, etc., can be used as one or more motors selected from automobile drive motors, camera focus adjustment motors, hard disk drive motors, motors built into computers, mobile terminals, mobile phones, etc.

[0122] [Adhesive Composition] The adhesive composition involved in this invention is an adhesive composition for bonding steel sheet laminates coated with a primer containing a copper compound. It contains (A) free radical polymerizable compounds, (B) organic peroxides, and (C) phosphate ester compounds with free radical polymerizable groups. The amount of (C) phosphate ester compound having free radical polymerizable groups is more than 0.055 parts by mass and less than 1 part by mass relative to 100 parts by mass of (A) free radical polymerizable compound.

[0123] The adhesive composition, primer, and steel plate are the same substances described in the <free radical polymerizable adhesive composition>, <copper compound-containing primer>, and <steel plate> of the [method for manufacturing steel plate laminate].

[0124] The adhesive composition of the present invention can be used to bond various steel plates, such as cold-rolled steel plates and electromagnetic steel plates, to manufacture steel plate laminates. In the bonding of steel plates to each other, especially in the bonding of steel plates with a coating containing stamping oil and copper compounds on their surface, the initial curing time (the time required for the bonded steel plates to become fixed and no longer move) can be significantly shortened. The initial curing time can be measured by the method described in the examples below, and for example, it can be set to less than 300 seconds, preferably less than 250 seconds, and more preferably less than 180 seconds.

[0125] In steel plate laminates made using the adhesive composition of the present invention, especially in steel plate laminates using electromagnetic steel plates, the cured adhesive layer not only functions as an insulating layer but also as a stress buffer layer for the steel plate. Therefore, when the steel plate laminate is used in the rotor, stator, etc. of an electric motor, current loss, stress concentration, and stress strain can be reduced, thus resulting in a high-efficiency, high-performance, and highly reliable motor.

[0126] Example The present invention will be specifically described below through embodiments, but the present invention is not limited to the following embodiments. In addition, unless otherwise specified, in each embodiment, "parts" means "parts by mass", and "%" means "% by mass". Furthermore, all entries in the table relating to proportions are in "parts" (parts by mass).

[0127] [Components of the adhesive composition] In the examples and comparative examples shown in Tables 1 to 3, the composition of the adhesive composition is as follows.

[0128] EP-MA: Epoxy methacrylate (a mixture of 60% by mass of epoxy methacrylate and 40% by mass of HEMA) (manufactured by DIC, "UE-8071-60BH") BPA-MA: Bisphenol A ethylene oxide adduct (approximately 2.6 mol) dimethacrylate (manufactured by Kyoei Chemical Co., Ltd., "Light Ester BP-2EMK") PUA1: Polyurethane (meth)acrylate oligomer (manufactured by Mitsubishi Chemical Corporation, "UV-1700") PUA2: Polyurethane (meth)acrylate oligomer (manufactured by Mitsubishi Chemical Corporation, "UV-3700B") HEMA: Hydroxyethyl methacrylate IBXMA: Isoborneol Methacrylate TCDDA: Dimethyloltricyclodecane diacrylate CHPO: Cumene hydroperoxide PM1: Monofunctional phosphate monomer (manufactured by Kyoei Chemical Co., Ltd., "Light Ester P-1M") PM2: A multifunctional phosphate monomer (manufactured by Kyoei Chemical Co., Ltd., "Light Ester P-2M") SAC: Saccharin (anaerobic catalyst) EDTA2Na: Disodium ethylenediaminetetraacetate (stabilizer) [Evaluation of Adhesive Properties] <Preparation of Experimental Steel Plates> Cold-rolled steel sheets with a thickness of 0.5 mm according to Japanese Industrial Standard JIS G 3141 were cut into dimensions of 25 mm wide × 100 mm long (W25 mm × L100 mm) to prepare experimental cold-rolled steel sheets.

[0129] Instead of cold-rolled steel sheet, a 0.25 mm thick electromagnetic steel sheet (Thinner Gauge Hiexcore 25HX1500 manufactured by Nippon Steel Corporation) was used. Otherwise, the experimental electromagnetic steel sheet was prepared in the same manner as the experimental cold-rolled steel sheet.

[0130] <Preparation of Primer> Collect 0.6 parts of a 60% toluene solution of copper neodecanoate, 49.4 parts of ethanol, and 50 parts of sheet metal stamping oil (manufactured by Nippon Oil Co., Ltd., "G-6338F"), mix them in a glass container to obtain a primer.

[0131] <Tensile shear bond strength of cold-rolled steel sheet> Prepare two cold-rolled steel sheets for the experiment. For one sheet, apply 0.018 mL of primer by spraying and allow it to dry at 25°C for 3 hours. For the other sheet, apply 0.03 mL of adhesive using a scraper, ensuring the bonding area is 25 mm wide × 12.5 mm long, and then adhere the primer-coated side to the adhesive-coated side. Then, press the two test sheets together using a pneumatic press for 200 seconds, and remove them to obtain the test sheet (equivalent to a steel sheet laminate).

[0132] The prepared test pieces were cured at 23°C for 24 hours, and then stretched using a universal tensile testing machine at a tensile speed of 0.5 mm / min. The tensile shear bond strength (N / mm²) of the cold-rolled steel sheet was obtained according to Japanese Industrial Standard JIS K 6850 (1999).

[0133] <Initial curing time of cold-rolled steel sheet> Prepare two cold-rolled steel sheets for testing, each 25mm wide and 100mm long.

[0134] Spray 0.018 ml of primer onto one end of a test cold-rolled steel sheet along its length and let it dry at 25°C for 3 hours.

[0135] Apply 0.03 ml of adhesive to one end of another cold-rolled steel sheet used for testing along its length using a scraper.

[0136] After applying the adhesive, immediately bond the primer-coated surface of the test cold-rolled steel sheet to the adhesive-coated surface in a bonding area of ​​25mm wide × 12.5mm long.

[0137] Then, the two laminated test cold-rolled steel plates are pressed and tightened for a specified time using a pneumatic press, and then removed to make a test piece (equivalent to a steel plate laminate).

[0138] After the test piece is prepared, one side of the cold-rolled steel plate is quickly fixed, and a 5kg weight is suspended on the other side of the cold-rolled steel plate. Parallel tensile and shear loads are applied to the bonding surface, and the bonding surface (bonded joint) of the test piece is visually confirmed to see if it has broken.

[0139] After the test piece is pressed and tightened using a pneumatic press, the time until the pressure is released is defined as the pneumatic press time. The pneumatic press time until the bonding surface of the test piece no longer breaks is defined as the initial curing time. In addition, the time for suspending the weights is 10 seconds.

[0140] For example, when the test piece is removed after being pressed and tightened by a pneumatic press for 20 seconds and then quickly suspended with a 5kg weight after its fabrication, the bonding surface of the test piece breaks. On the other hand, when the test piece is removed after being pressed and tightened by a pneumatic press for 30 seconds and then quickly suspended with a 5kg weight after its fabrication, if the bonding surface of the test piece does not break, the initial curing time is 30 seconds.

[0141] <Tensile Shear Bond Strength of Electromagnetic Steel Sheets> Prepare two test electromagnetic steel plates, each 25mm wide and 100mm long.

[0142] Spray 0.018 ml of primer onto one end of a test electromagnetic steel plate along its length and let it dry at 25°C for 3 hours.

[0143] Apply 0.03 ml of adhesive to one end of another test electromagnetic steel plate along its length using a scraper.

[0144] After applying the adhesive, immediately bond the primer-coated surface of the test electromagnetic steel plate to the adhesive-coated surface in a bonding area of ​​25mm wide × 12.5mm long.

[0145] Then, the two laminated test electromagnetic steel plates were pressed and tightened for 200 seconds using a pneumatic press and then removed to make a test piece.

[0146] The prepared test pieces were cured at 23℃ for 24 hours. A universal tensile testing machine was used to perform tensile testing along a direction parallel to the bonding surface at a tensile speed of 0.5 mm / min. The tensile shear bond strength (N / mm²) of the electromagnetic steel sheet was determined according to Japanese Industrial Standard JIS K 6850 (1999). 2 ).

[0147] <Initial curing time of electromagnetic steel sheet> Prepare two test electromagnetic steel plates, each 25mm wide and 100mm long.

[0148] Spray 0.018 ml of primer onto one end of a test cold-rolled steel sheet along its length and let it dry at 25°C for 3 hours.

[0149] Apply 0.03 ml of adhesive to one end of another cold-rolled steel sheet used for testing along its length using a scraper.

[0150] After applying the adhesive, immediately bond the primer-coated surface of the test electromagnetic steel plate to the adhesive-coated surface in a bonding area of ​​25mm wide × 12.5mm long.

[0151] Then, the two laminated test electromagnetic steel plates are pressed and tightened for a specified time using a pneumatic press, and then removed to make test pieces.

[0152] After the test piece is made, one side of the cold-rolled steel plate is quickly fixed, and a 5kg weight is suspended on the other side of the cold-rolled steel plate. Parallel tensile and shear loads are applied to the bonding surface, and the bonding surface (bonded joint) of the test piece is visually confirmed to see if it has broken.

[0153] After the test piece is pressed and tightened using a pneumatic press, the time until the pressure is released is defined as the pneumatic press time. The pneumatic press time until the bonding surface of the test piece no longer breaks is defined as the initial curing time. In addition, the time for suspending the weights is 10 seconds.

[0154] For example, when the test piece is removed after being pressed and tightened by a pneumatic press for 20 seconds and then quickly suspended with a 5kg weight after its fabrication, the bonding surface of the test piece breaks. On the other hand, when the test piece is removed after being pressed and tightened by a pneumatic press for 30 seconds and then quickly suspended with a 5kg weight after its fabrication, if the bonding surface of the test piece does not break, the initial curing time is 30 seconds.

[0155] [Examples 1-5] Each component listed in Table 1 was collected in the amounts (parts by mass) recorded in Table 1 and mixed in a glass container to prepare an adhesive composition.

[0156] The obtained adhesive composition was used to determine the tensile shear bond strength, initial curing time, and tensile shear bond strength and initial curing time of cold-rolled steel sheets, as well as electromagnetic steel sheets. The results are combined and shown in Table 1.

[0157] [Examples 6-12] Each component listed in Table 2 was collected in the amounts (parts by mass) specified in Table 2 and mixed in a glass container to prepare an adhesive composition.

[0158] The obtained adhesive composition was used to determine the tensile shear bond strength and initial curing time of cold-rolled steel sheets. The results are combined and shown in Table 2.

[0159] [Comparative Examples 1-7] Each component listed in Table 3 was collected in the amounts (parts by mass) specified in Table 3 and mixed in a glass container to prepare an adhesive composition.

[0160] The obtained adhesive composition was used to determine the tensile shear bond strength and initial curing time of cold-rolled steel sheets. The results are combined and shown in Table 3.

[0161] [Table 1]

[0162] [Table 2]

[0163] [Table 3]

[0164] As can be seen from Examples 1-5 in Table 1 and Examples 6-12 in Table 2, the method for preparing the steel plate laminate and the free radical polymerizable adhesive composition of the present invention exhibit excellent tensile shear bond strength and rapid curing properties (initial curing time less than 300 seconds) when using steel plates (cold-rolled steel plates and electromagnetic steel plates) with stamping oil (stamping oil) on their surfaces to form the steel plate laminate.

[0165] As can be seen from Comparative Examples 1 to 7 in Table 3, when the steel sheet laminate of the present invention is constructed using steel sheets (cold-rolled steel sheets and electromagnetic steel sheets) with stamping oil (stamping oil) on the surface, the amount of phosphate ester compound with free radical polymerizable groups (C) is outside the scope of the present invention, and therefore the tensile shear bond strength and / or rapid curing properties (initial curing time less than 300 seconds) are not satisfactory.

Claims

1. A method for manufacturing a steel plate laminate, characterized in that, It uses a free radical polymerizable adhesive composition to bond a steel plate coated with a primer containing a copper compound. The free radical polymerizable adhesive composition contains (A) a free radical polymerizable compound, (B) an organic peroxide, and (C) a phosphate ester compound having free radical polymerizable groups, wherein, relative to 100 parts by mass of (A) the free radical polymerizable compound, the amount of (C) the phosphate ester compound having free radical polymerizable groups is 0.055 parts by mass or more and less than 1 part by mass.

2. A steel plate laminate, characterized in that, It is a steel plate laminate manufactured by the method described in claim 1.

3. An adhesive composition for bonding a steel sheet laminate coated with a copper-containing primer, characterized in that, It contains (A) a free radical polymerizable compound, (B) an organic peroxide, and (C) a phosphate ester compound with a free radical polymerizable group. The amount of (C) phosphate ester compound having free radical polymerizable groups is more than 0.055 parts by mass and less than 1 part by mass relative to 100 parts by mass of (A) free radical polymerizable compound.

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