Primer composition

Abstract

To provide a primer for rubber adhesion that improves adhesiveness of an adhesive to rubber.SOLUTION: A primer composition for rubber adhesion includes at least one kind of metal selected from vanadium and iron.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a primer composition. [Background technology]

[0002] Seals are used in automobile parts, electrical parts, and the like. For example, seals are used in the oil pan, transmission case, motor case, and the like of automobile engines. To prevent misalignment between these parts and the seal, a method of fixing the seal and the part using an adhesive is used. Rubber is generally used as the material for the seal, but rubber is a difficult-to-bond material, so an adhesive that can firmly bond the seal and the part is required.

[0003] For example, Patent Document 1 describes a two-component epoxy adhesive for bonding olefinic rubber, which comprises (A) a base agent containing an epoxy compound and (B) a curing agent containing an amine compound. According to Patent Document 1, this two-component epoxy adhesive for bonding olefinic rubber is capable of exhibiting sufficient adhesive strength to olefinic rubbers such as EPDM without the need for special treatments such as corona discharge or primer application. For example, Patent Document 2 describes an active energy ray-reactive crosslinking adhesive containing a bisphenol compound (A), a conjugated diene polymer (B), a crosslinkable acrylate (C), and a specific blocked isocyanate (D). According to Patent Document 2, the active energy ray-reactive crosslinking adhesive has excellent adhesive properties, excellent storage stability, a low environmental impact, and good adhesive properties for bonding rubber and polyester resin materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-045450 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-185126 Summary of the Invention [Problem to be solved by the invention]

[0005] The adhesive described in Patent Document 1 is a thermosetting adhesive, and the adhesive described in Patent Document 2 is a UV-curing adhesive, both of which are designed for bonding rubber. As exemplified in Patent Documents 1 and 2, commonly known adhesives include UV-curing adhesives, thermosetting adhesives, and moisture-curing adhesives. Each of these adhesives has limitations on its use. UV-curing adhesives require a UV irradiation device, which limits the location where the bonding work can be performed. Furthermore, since areas that cannot be irradiated with UV do not cure, there are limitations on the materials that can be used. Even thermosetting adhesives require a heating oven, and simpler methods are needed. Furthermore, thermosetting adhesives require a long time to cure, which reduces production efficiency. Moisture-curing adhesives require a long time to cure, which reduces production efficiency. Another problem is that it is difficult to determine whether the adhesive has cured to the center. As described above, the adhesives conventionally used for bonding rubber have problems in terms of equipment and productivity, and the application of new adhesives has been desired. An object of the present invention is to provide a new rubber bonding method that does not require the introduction of additional equipment, does not limit the bonding work location, and uses a fast-curing adhesive. More specifically, an object of the present invention is to provide a primer composition for rubber bonding that improves the adhesion of adhesives to rubber. [Means for solving the problem]

[0006] The present specification provides the following means. [1] A primer for rubber adhesion containing at least one metal selected from vanadium and iron. [2] The rubber adhesion primer according to [1], further comprising a phosphate ester compound. [3] The primer for rubber adhesion according to [1] or [2], which is a primer for acrylic rubber or diene rubber. [4] A rubber adhesive comprising the primer composition for rubber adhesion according to any one of [1] to [3] and an anaerobic adhesive containing a radical polymerizable compound and an anaerobic curing catalyst. [5] An adhesive laminate in which a substrate (1) and a substrate (2) are bonded via an adhesive layer, At least one of the substrate (1) and the substrate (2) is rubber, The adhesive laminate comprises an adhesive layer containing a polymer of a radically polymerizable compound and at least one metal selected from vanadium and iron. [Effects of the Invention]

[0007] According to the present invention, a primer composition capable of improving the adhesive strength of an anaerobic adhesive can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Primer composition> The primer composition accelerates the curing of the anaerobic adhesive and is used in combination with the anaerobic adhesive. Generally, the primer composition and the anaerobic adhesive are applied to separate adherends, and when the two coated surfaces are brought together during bonding, the primer composition and the anaerobic adhesive come into contact, initiating the curing reaction of the anaerobic adhesive and firmly bonding the adherends.

[0009] The primer composition includes an anaerobic cure accelerator and, optionally, a diluent, which is an optional component and does not necessarily require the primer composition to contain a diluent.

[0010] 1.Anaerobic hardening accelerator Anaerobic cure accelerators are accelerators that contribute to the initiation of anaerobic curing of anaerobic adhesives. The anaerobic cure accelerator contains at least one metal selected from the group consisting of vanadium and iron. By including an anaerobic cure accelerator containing these metals in a primer composition, adhesion to rubber can be imparted to the anaerobic adhesive used in combination. The anaerobic cure accelerator is preferably at least one compound selected from the group consisting of vanadium compounds or iron compounds. Examples of such compounds include inorganic acid salts, organic acid salts, complex salts, and mixtures thereof of vanadium or iron. Examples of inorganic acid salts include nitrates and sulfates. Examples of organic acid salts include acetates, naphthenates, hexanoates, and propionates. Examples of ligands that form complex salts include β-diketones such as acetylacetone, dibenzoylmethane, and benzoylacetone, and β-ketoesters such as methyl acetoacetate and ethyl acetoacetate. Examples of iron compounds include iron nitrate, iron sulfate, iron acetate, iron acrylate, iron hexoate, iron propionate, iron 2-ethylhexanoate, dicyclopentadienyl iron, iron naphthate, etc. Examples of vanadium compounds include vanadium acetylacetonate, vanadyl acetylacetonate, vanadyl stearate, vanadium naphthenate, vanadium benzoylacetonate, vanadium oxalate, ammonium metavanadate, sodium metavanadate, vanadium pentoxide, and a reaction product of vanadium pentoxide with a phosphate ester (e.g., dibutyl phosphate).

[0011] The content of the anaerobic curing accelerator in the primer composition is preferably 0.01 to 30 mass%, more preferably 0.02 to 25 mass%, and particularly preferably 0.05 to 20 mass%. The content of the anaerobic curing accelerator in the primer composition may be appropriately changed according to the desired conditions.

[0012] 2. Diluent The diluent is not particularly limited as long as it is liquid at room temperature. Examples of the diluent include press oil, organic solvents, and radically polymerizable monomers and oligomers. One type of diluent may be used alone, or two or more types of diluents may be mixed and used.

[0013] The press oil may be one commonly used in press working of thin metal sheets such as steel sheets. Applying the press oil during press working removes foreign matter adhering to the steel sheet surface and prevents galling caused by the die during press working. The press oil may contain, for example, a mineral oil or synthetic oil commonly used as a base oil for rust preventative oils or metalworking oils. It may contain one type of mineral oil or synthetic oil alone, or a combination of two or more types. Examples of mineral oils include paraffinic and naphthenic refined mineral oils obtained by refining fractions obtained by distilling crude oil. Examples of synthetic oils include hydrocarbon synthetic oils such as paraffinic, naphthenic, and olefinic oils, and ester synthetic oils. When the diluent is a press oil, applying the press oil before punching the steel sheet can omit the step of applying the primer composition when the primer composition is used for laminating or bonding steel sheets.

[0014] Examples of organic solvents include alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, halogenated hydrocarbons such as dichloromethane, chloroform, 1.1.1-trichloroethane, and Freon, hydrocarbons such as n-hexane and toluene, ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate and butyl acetate. To increase the solubility of the diluent, a highly soluble organic solvent such as N,N-dimethylformamide or dimethyl sulfoxide may be mixed and used as the diluent.

[0015] Examples of the polymerizable monomer include (meth)acrylic acid esters such as monofunctional (meth)acrylates, and specific examples thereof include lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, nonylphenoxytetraethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, butoxytriethylene glycol ( (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylhexyl polyethylene glycol (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, modified butyl (meth)acrylate, epichlorohydrin-modified phenoxy (meth)acrylate, ethylene oxide-modified succinic acid (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, morpholino (meth)acrylate, and the like.

[0016] An oligomer having a (meth)acryloyl group at its terminal may be used as the (meth)acrylic acid ester. Specific examples of oligomers having a (meth)acryloyl group at their terminal include urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate. In more detail, the oligomer may be the same as the oligomer having a (meth)acryloyl group at its terminal contained in the anaerobic adhesive described below.

[0017] In this specification, an oligomer is a polymer having a weight-average molecular weight of 500 or more but less than 5,000, and a polymer is a polymer having a weight-average molecular weight of 5,000 or more. Note that the molecular weight in this specification refers to the value obtained by converting the weight-average molecular weight measured by GPC (gel permeation chromatography) using polystyrene as a standard substance.

[0018] The viscosity of the primer composition can be adjusted within an appropriate range by adjusting the amount of diluent. The viscosity of the diluent is preferably 0.1 mPa·s to 1,000 mPa·s, more preferably 0.15 mPa·s to 800 mPa·s, and particularly preferably 0.2 mPa·s to 600 mPa·s. In this specification, viscosity is a value measured using a rotational viscometer as described in JIS K 7117:1999 at a test temperature of 25°C.

[0019] The viscosity of the primer composition is preferably 0.1 mPa·s to 1,000 mPa·s, more preferably 0.2 mPa·s to 900 mPa·s, and particularly preferably 0.3 mPa·s to 800 mPa·s.

[0020] The primer composition may be applied to the substrate by a known method, such as by roller, dispensing, spraying, inkjet printing, or dipping.

[0021] 3. Adhesion promoter Unlike anaerobic curing accelerators, adhesion promoters do not directly cure anaerobic adhesives, but they are components that improve the adhesive strength of anaerobic adhesives. Adhesion promoters are preferably soluble in diluents. Adhesion promoters preferably contain functional groups or elements that can chemically or physically interact with components such as rubber or metal contained in the adherend to which the primer composition is applied. Adhesion promoters containing such functional groups or elements can be more effective in improving the adhesive strength of anaerobic adhesives. To achieve adhesion, adhesion promoters are preferably compounds that partially erode the surface of adherends such as rubber or metal through chemical action, or compounds that form covalent or hydrogen bonds with hydroxyl groups present on the surface of the adherend. While adhesion promoters may be added to anaerobic adhesives, adding them to primer compositions may sometimes enhance the adhesive strength improvement effect. The inclusion of an adhesion promoter in a primer composition can increase the concentration of adhesion promoter on the surface of the adherend. This allows the functional groups or elements contained in the adhesion promoter to efficiently interact with the adherend, thereby enhancing the adhesive strength improvement effect. Examples of functional groups include -OH, -COOH, -OR, -COOR (R is an alkyl group, preferably an alkyl group having 1 to 5 carbon atoms), and SH, and examples of elements include aluminum, phosphorus, and nitrogen. Furthermore, the adhesion promoter may have a radical polymerizable group (a group having an ethylenically unsaturated bond). When the adhesion promoter has a radical polymerizable group, the adhesive strength of the adhesive to the adherend can be further improved.

[0022] Specific examples of the adhesion promoter include silane coupling agents, aluminum chelates, phosphate ester compounds, nitrogen-containing compounds, thiol-containing compounds, organic acids, and organic acid derivatives. These adhesion promoters may be used alone or in combination of two or more.

[0023] Silane coupling agents are compounds having one or more alkoxysilyl groups in one molecule, such as alkylalkoxysilanes, aminoalkoxysilanes, epoxyalkoxysilanes, vinylalkoxysilanes, and alkoxysilyl group-containing (meth)acrylates.

[0024] Specific examples of alkylalkoxysilanes include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, triethoxysilane, and n-propyltrimethoxysilane.

[0025] Specific examples of aminoalkoxysilanes include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane.

[0026] Specific examples of epoxyalkoxysilanes include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane.

[0027] Specific examples of vinylalkoxysilanes include vinyltrimethoxysilane, vinyltriethoxysilane, and vinylmethyldimethoxysilane.

[0028] Specific examples of alkoxysilyl group-containing (meth)acrylates include 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, and 3-(meth)acryloxypropyltriethoxysilane.

[0029] The aluminum chelate is preferably a complex compound in which at least one β-ketoenolate anion is coordinated to aluminum. The coordination number of the β-ketoenolate anion may be 1, 2, or 3. The aluminum chelate more preferably has an alkoxy group. Hydroxyl groups on the metal surface and the alkoxy groups of the aluminum chelate bond via a dealcoholization reaction, thereby improving the adhesion between the anaerobic adhesive and the metal surface. The alkoxy group may have 1 to 10 carbon atoms, preferably 1 to 5.

[0030] Representative aluminum chelate compounds include ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis(ethyl acetoacetate), aluminum tris(acetylacetate), aluminum monoacetylacetate bis(ethyl acetoacetate), aluminum di-n-butoxide monomethyl acetoacetate, aluminum diisobutoxide monomethyl acetoacetate, and aluminum di-sec-butoxide monomethyl acetoacetate.

[0031] The phosphate ester compound preferably has a group represented by the following general formula (1) or (2).

[0032] [ka]

[0033] The phosphate ester compound is particularly preferably a compound represented by the following general formula (3).

[0034] [ka] In the formula, R is independently an alkyl group having 1 to 5 carbon atoms, provided that the alkyl group may be substituted with a (meth)acryloxy group, a vinyl group, or an allyl group;

[0035] Specific examples of the phosphate ester compound include monobutyl phosphate, dibutyl phosphate, tributyl phosphate, and 2-hydroxyethyl methacrylate acid phosphate.

[0036] The nitrogen atom-containing compound preferably contains a nitrogen-containing functional group (e.g., amino group, amide group, imide group, etc.) or a nitrogen-containing heterocyclic structure. Among these, nitrogen atom-containing radical polymerizable monomers and aromatic amines are preferred.

[0037] Specific examples of radically polymerizable monomers containing a nitrogen atom include monomers having a maleimide skeleton, such as N-phenylmaleimide, N-(4-hydroxyphenyl)maleimide, N-(4-acetylphenyl)maleimide, N-(4-methoxyphenyl)maleimide, N-(4-ethoxyphenyl)maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, and N-benzylmaleimide. Other examples include compounds having an amide bond in which a (meth)acryloyl group is bonded to a nitrogen atom, such as acryloylmorpholine.

[0038] Specific examples of aromatic amines include toluidine, N,N-dimethyl-para-toluidine, N,N-dimethylaniline, aniline, 4-methoxyaniline, aminophenol, and bis(4-aminophenyl)methane.

[0039] Examples of thiol-containing compounds include aliphatic thiols such as 1-dodecanethiol, 1-butanethiol, 1,3-propanedithiol, etc. Silane coupling agents containing thiols, such as 3-(trimercaptopropyl)trimethoxysilane, can also be preferably used.

[0040] The organic acid is preferably a carboxylic acid, and the organic acid derivative is preferably a carboxylic acid derivative. Specific examples of organic acids and organic acid derivatives include compounds containing multiple acid functional groups in one molecule, such as phthalic acid, trimellitic acid, and pyromellitic acid, organic acids having a radical polymerizable group, such as (meth)acrylic acid, and organic acid derivatives having a radical polymerizable group, such as (meth)acrylic acid esters. In addition to esters, acid anhydrides and the like can also be used as organic acid derivatives. Among these, organic acids and organic acid derivatives having a radical polymerizable group are particularly preferred.

[0041] Examples of the (meth)acrylic acid ester include monofunctional (meth)acrylates, and specific examples thereof include lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, nonylphenoxytetraethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, and butoxytriethylene glycol (meth)acrylate. acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylhexyl polyethylene glycol (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, modified butyl (meth)acrylate, epichlorohydrin-modified phenoxy (meth)acrylate, ethylene oxide-modified succinic acid (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, morpholino (meth)acrylate, and the like.

[0042] An oligomer having a (meth)acryloyl group at its terminal may be used as the (meth)acrylic acid ester. Specific examples of oligomers having a (meth)acryloyl group at their terminal include urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate. In more detail, the oligomer may be the same as the oligomer having a (meth)acryloyl group at its terminal contained in the anaerobic adhesive described below.

[0043] Some adhesion promoters can also be used as diluents. Such adhesion promoters are called "adhesion promoters with diluent functions." Adhesion promoters with diluent functions are preferably liquid at room temperature and have low viscosity. For example, among the above-described (meth)acrylic acid esters and oligomers having a (meth)acryloyl group at the end, those with low viscosity (for example, viscosity comparable to that of the above-described diluents) can also be used as diluents, and are adhesion promoters with diluent functions.

[0044] When an adhesion promoter having a diluent function is used, the amount of diluent used can be reduced, and in some cases, diluent need not be used at all. Thus, when an adhesion promoter having a diluent function is used, the content of adhesion promoter in the primer composition may be high. Therefore, the content of adhesion promoter in the primer composition needs to be considered separately for cases where an adhesion promoter having a diluent function is used as a diluent and other cases.

[0045] The content of the adhesion promoter in the primer composition is preferably 0.01 to 30 mass%, more preferably 0.1 to 20 mass%, and particularly preferably 1 to 10 mass%. When at least a portion of the diluent is replaced with an adhesion promoter having the function of a diluent, the content of the adhesion promoter in the primer composition is not particularly limited and may be, for example, in the range of 0.1 to 99.9 mass%, and preferably 1 to 99 mass%.

[0046] The adhesion promoter can impart particularly high adhesive strength to the anaerobic adhesive by combining it with a specific anaerobic curing accelerator. For example, a combination of an anaerobic curing accelerator containing vanadium and a phosphate ester compound is a preferred example.

[0047] <Anaerobic adhesive> An anaerobic adhesive is an adhesive that begins to cure when oxygen is blocked in the presence of metal ions. The anaerobic adhesive used in this embodiment is not particularly limited, and any known adhesive may be used. For example, a commonly used anaerobic adhesive containing a radical polymerizable compound and a radical polymerization initiator may be used. The anaerobic adhesive may further contain an anaerobic curing catalyst in addition to these.

[0048] 1. Radical polymerizable compounds The radically polymerizable compound is a compound having a radically polymerizable group, and is particularly preferably a (meth)acrylic acid ester. Examples of the (meth)acrylic acid ester include acrylic monomers and acrylic oligomers such as monofunctional (meth)acrylates and polyfunctional (meth)acrylates.

[0049] Examples of monofunctional (meth)acrylates include lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, nonylphenoxytetraethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, butoxytriethylene glycol (meth)acrylate, 2-ethylhexyl Examples of such an acrylate include silyl (meth)acrylate, 2-ethylhexyl polyethylene glycol (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, modified butyl (meth)acrylate, epichlorohydrin-modified phenoxy (meth)acrylate, ethylene oxide-modified succinic acid (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and morpholino (meth)acrylate.

[0050] Examples of polyfunctional (meth)acrylates include 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol 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, hydroxypivalic acid ester neopentyl glycol diacrylate, caprolactone-modified hydroxypivalic acid 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 Examples of such an alkyl acrylate include hydrin-modified glycerol tri(meth)acrylate, tris(acryloyloxyethyl)isocyanurate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, alkyl-modified dipentaerythritol pentaacrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0051] The anaerobic adhesive may include a polymer or oligomer having a terminal (meth)acryloyl group.

[0052] The polymer or oligomer having a (meth)acryloyl group at its terminal is not particularly limited, but from the viewpoint of anaerobic curability, it is preferably at least one compound selected from the group consisting of urethane (meth)acrylate, epoxy (meth)acrylate, ester (meth)acrylate, isoprene-based (meth)acrylate, hydrogenated isoprene-based (meth)acrylate, and (meth)acrylic group-containing acrylic polymer, more preferably urethane (meth)acrylate or epoxy (meth)acrylate, and particularly preferably urethane (meth)acrylate.

[0053] Examples of urethane (meth)acrylates include reaction products of polyhydric alcohols, polyhydric isocyanates, and hydroxy (meth)acrylate compounds, and reaction products of polyhydric isocyanates and hydroxy (meth)acrylate compounds without using polyhydric alcohols. Specific examples of polyhydric alcohols include polyether polyols such as polypropylene glycol and polytetramethylene glycol, polyester polyols obtained by reacting a polyhydric alcohol with a polybasic acid, caprolactone polyols obtained by reacting a polyhydric alcohol with a polybasic acid and ε-caprolactone, and polycarbonate polyols (e.g., polycarbonate polyols obtained by reacting 1,6-hexanediol with diphenyl carbonate). Specific examples of organic polyisocyanates include isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and dicyclopentanyl diisocyanate. As the urethane (meth)acrylate, those produced from polyether polyol, polyester polyol, or polycarbonate polyol as the raw material polyol are preferred because of their excellent weather resistance, transparency, and adhesive strength. As the raw material organic polyisocyanate, those produced from isophorone diisocyanate, hexamethylene diisocyanate, or xylene diisocyanate are preferred because of their excellent weather resistance.

[0054] Examples of the urethane (meth)acrylate include urethane (meth)acrylate having a polybutadiene skeleton, urethane (meth)acrylate having a hydrogenated polybutadiene skeleton, urethane (meth)acrylate having a polycarbonate skeleton, urethane (meth)acrylate having a hydrogenated bisphenol A skeleton, urethane (meth)acrylate having a polyether skeleton, urethane (meth)acrylate having a polyester skeleton, and urethane (meth)acrylate having a castor oil skeleton.

[0055] Examples of epoxy (meth)acrylates include (meth)acrylates obtained by reacting a conventionally known epoxy resin, such as an aromatic epoxy resin, an alicyclic epoxy resin, or an aliphatic epoxy resin, with (meth)acrylic acid.

[0056] 2. Radical polymerization initiator Examples of the radical polymerization initiator include organic peroxides and photoradical generators, but from the viewpoint of anaerobic curability, organic peroxides are preferred.

[0057] Examples of organic peroxides include hydroperoxides, ketone peroxides, diallyl peroxides, peroxy esters, and other organic peroxides, and specific examples include cumene hydroperoxide, t-butyl hydroperoxide, p-methane hydroperoxide, methyl ethyl ketone peroxide, cyclohexane peroxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, etc. From the viewpoint of storage stability, hydroperoxides are preferably used.

[0058] From the viewpoint of excellent anaerobic curing properties, the organic peroxide is preferably an organic peroxide having a one-hour half-life temperature in the range of 80° C. to 300° C., more preferably an organic peroxide having a one-hour half-life temperature in the range of 100° C. to 200° C. The one-hour half-life temperature is a value measured by thermal decomposition in benzene at a peroxide concentration of 0.1 mol / L.

[0059] Examples of organic peroxides having a one-hour half-life temperature in the range of 80° C. to 300° C. include hydroperoxides. Specific examples of hydroperoxides include p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide.

[0060] The photoradical generator is not particularly limited, but examples thereof include an acetophenone-based photoradical polymerization initiator, a benzoin-based photoradical polymerization initiator, a benzophenone-based photoradical polymerization initiator, a thioxanthone-based photoradical polymerization initiator, an acylphosphine oxide-based photoradical polymerization initiator, and a titanocene-based photoradical polymerization initiator.

[0061] Examples of acetophenone-based photoradical polymerization initiators include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer.

[0062] Commercially available acetophenone-based photoradical polymerization initiators include Omnirad184, Omnirad1173, Omnirad2959, and Omnirad127 (manufactured by IGM Resins), and ESACUREKIP-150 (manufactured by Lamberti Spa).

[0063] Examples of the acylphosphine oxide-based photoradical polymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0064] Commercially available acylphosphine oxide-based photoradical polymerization initiators include OmniradTPO and Omnirad819 (manufactured by IGM Resins BV).

[0065] The anaerobic adhesive may contain one type of radical polymerization initiator alone, or may contain two or more types of radical polymerization initiators.

[0066] From the viewpoint of anaerobic curing, the content of the radical polymerization initiator is preferably 0.05% by mass to 20% by mass, more preferably 0.1% by mass to 10% by mass, and particularly preferably 0.5% by mass to 5% by mass, relative to the total mass of the anaerobic adhesive.

[0067] 3.Anaerobic curing catalyst The anaerobic adhesive may further contain an anaerobic curing catalyst. The anaerobic curing catalyst is thought to react with a metal compound in the primer composition to generate active metal ions, which then promote the generation of radicals through the reaction of the metal ions with the radical polymerization initiator. However, this mechanism is speculative and does not limit the present invention.

[0068] Examples of the anaerobic curing catalyst include saccharin, amine compounds, azole compounds, mercaptan compounds, hydrazine compounds, and salts thereof.

[0069] Among these, a combination of saccharin and a hydrazine compound or a salt thereof is preferred from the viewpoint of anaerobic curability.

[0070] Examples of the amine compound include heterocyclic secondary amines such as 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroquinaldine, etc.; heterocyclic tertiary amines such as quinoline, methylquinoline, quinaldine and quinoxalinephenazine, etc.; and aromatic tertiary amines such as N,N-dimethyl-anisidine, N,N-dimethylaniline and N,N'-dimethyl-p-toluidine, etc.

[0071] Examples of the azole compound include 1,2,4-triazole, oxazole, oxadiazole, thiadiazole, benzotriazole, hydroxybenzotriazole, benzoxazole, 1,2,3-benzothiadiazole, and 3-mercaptobenzotriazole.

[0072] Examples of the mercaptan compound include linear mercaptans such as n-dodecyl mercaptan, ethyl mercaptan, and butyl mercaptan.

[0073] Examples of hydrazine compounds include 1-acetyl-2-phenylhydrazine, 1-acetyl-2(p-tolyl)hydrazine, 1-benzoyl-2-phenylhydrazine, 1-(1',1',1'-trifluoro)acetyl-2-phenylhydrazine, 1,5-diphenyl-carbohydrazine, 1-formyl-2-phenylhydrazine, 1-acetyl-2-(p-bromophenyl)hydrazine, 1-acetyl-2-(p-nitrophenyl)hydrazine, 1-acetyl-2-(2'-phenylethylhydrazine), p-nitrophenylhydrazine, and p-trisulfonylhydrazide.

[0074] Examples of salts of hydrazine compounds include 4-methylsulfonylphenylhydrazine hydrochloride, hydrazine monohydrochloride, and p-tolylhydrazine hydrochloride.

[0075] The anaerobic adhesive may contain one type of anaerobic curing catalyst alone, or may contain two or more types of anaerobic curing catalysts.

[0076] From the viewpoint of anaerobic curing properties, the content of the anaerobic curing catalyst is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, relative to the total mass of the anaerobic adhesive, and the upper limit is preferably 30% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less.

[0077] 4. Adhesion promoter The anaerobic adhesive may contain an adhesion promoter similar to that used as an optional component in a primer composition. Here, radically polymerizable compounds such as (meth)acrylic acid esters can be the main component of an anaerobic adhesive, but are excluded from the adhesion promoters contained in anaerobic adhesives. For example, the anaerobic adhesive may contain an adhesion promoter selected from the group consisting of silane coupling agents, aluminum chelates, and phosphate ester compounds.

[0078] The adhesion promoter contained in the primer composition and the adhesion promoter contained in the anaerobic adhesive may be the same or different. While the adhesive strength of the anaerobic adhesive can be improved by adding an adhesion promoter only to the anaerobic adhesive, the adhesive strength improvement effect may be further enhanced by including an adhesion promoter in both the anaerobic adhesive and the primer composition, or in the primer composition alone. The content of the adhesion promoter (excluding radically polymerizable compounds) in the anaerobic adhesive is preferably 0.01 to 8 mass %, more preferably 0.05 to 5 mass %.

[0079] The total amount of adhesion promoter (excluding radical polymerizable compounds) contained in the primer composition and the anaerobic adhesive is preferably 0.005 to 10 mass%, more preferably 0.01 to 5 mass%, and particularly preferably 0.02 to 1 mass%. Having the adhesion promoter content within any of these ranges allows the anaerobic adhesive to exhibit high adhesive strength. The mass ratio of the adhesion promoter contained in the primer composition to the adhesion promoter (excluding radical polymerizable compounds) contained in the anaerobic adhesive is preferably 0.005 to 100, more preferably 0.008 to 80, and particularly preferably 0.01 to 50. The mass ratio of the adhesion promoter contained in the primer composition to the adhesion promoter (excluding radical polymerizable compounds) contained in the anaerobic adhesive is calculated using the formula: (mass of adhesion promoter contained in the primer composition) / (mass of adhesion promoter contained in the anaerobic adhesive).

[0080] The anaerobic adhesive may be applied to the substrate by a known method, for example, the primer composition may be applied by a roller, dispensing, spraying, inkjet printing, or dipping.

[0081] 5. Other Ingredients The adhesive composition may contain additives such as fillers, various elastomers, antioxidants, light stabilizers, heavy metal deactivators, silane coupling agents, tackifiers, plasticizers, antifoaming agents, pigments, rust inhibitors, leveling agents, dispersants, rheology modifiers, and flame retardants, as long as the above-mentioned effects are not impaired.

[0082] <Adherend> The primer composition can improve the adhesion of anaerobic adhesives to rubber and can be preferably used as a primer composition for rubber bonding. As described below, an adhesive laminate can be produced using the primer composition and the anaerobic adhesive, and it is preferable that at least one of the adherends is rubber. The primer composition and the anaerobic adhesive can be used to bond, for example, rubber to rubber or rubber to metal. At least one of the adherends is rubber. Such an adherend may contain small amounts of components other than rubber, but the main component is rubber, and the rubber content may be 80% by mass or more, or even 100% by mass. The other adherend is not particularly limited, but the material other than rubber is preferably metal. The adherend may contain small amounts of components other than metal, but the main component is metal, and the metal content may be 80% by mass or more, or even 100% by mass.

[0083] The type of rubber used for the adherend is not particularly limited, but solid rubber having rubber elasticity at room temperature (25° C.) is preferably used. Specific examples of rubber include acrylic rubber (hereinafter also referred to as ACM), ethylene propylene diene rubber (hereinafter also referred to as EPDM), silicone rubber, chloroprene rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, chloroprene rubber, butadiene rubber, isoprene rubber, butyl rubber, and natural rubber.

[0084] <Adhesive laminate> An adhesive laminate can be produced by bonding at least two adherends using a primer composition and an anaerobic adhesive. In the adhesive layer of the adhesive laminate, the primer composition and the anaerobic adhesive are mixed near the interface to form an adhesive containing the primer composition and the anaerobic adhesive. The anaerobic adhesive may contain any of the above-mentioned components, for example, it may contain a radical polymerizable compound and an anaerobic curing catalyst. As described above, the primer composition is preferably used as a primer composition for bonding rubber, and an adhesive containing the primer composition and the anaerobic adhesive is also suitable for use with rubber as an adherend, and is preferably used as a rubber adhesive.

[0085] The adhesive laminate may comprise, in this order, a first adherend layer, an adhesive layer containing a cured product of an anaerobic adhesive, and a second adherend layer. The cured product of the anaerobic adhesive may contain components such as an anaerobic curing accelerator and an adhesion promoter contained in the primer composition. [Example]

[0086] The present invention will be specifically described below based on examples.

[0087] Anaerobic adhesive A was prepared by mixing the raw material components shown in Table 1 below in a mixer at room temperature for 60 minutes.

[0088] [Table 1]

[0089] The abbreviations listed in Table 1 represent the following compounds. UMA: Aliphatic bifunctional urethane methacrylate HEMA: 2-hydroxyethyl methacrylate, manufactured by Mitsubishi Gas Chemical Company, Inc. IBXMA: Isobornyl methacrylate, manufactured by Tokyo Chemical Industry Co., Ltd. KBM-503: 3-methacryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. "KBM-503" HOA-MPE: 2-acryloyloxyethyl-2-hydroxyethyl phthalate, "HOA-MPE" manufactured by Kyoeisha Chemical Co., Ltd. Stabilizers: MQ: 4-Methoxyphenol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Omnirad 184: "Omnirad 184" made by IGM Resins Percumyl H: Cumene hydroperoxide, NOF Corporation's "Percumyl H"

[0090] In each example, a primer composition was prepared by mixing the raw material components (metal species, adhesion promoter, solvent) shown in Table 2 below in a mixer at room temperature for 60 minutes. The primer composition of each example was combined with anaerobic adhesive A having the formulation in Table 1, and the primer composition was evaluated.

[0091] The abbreviations for the anaerobic curing accelerators and adhesion promoters listed in Table 2 refer to the following compounds. DBP-V: reaction product of vanadium pentoxide and dibutyl phosphate V(acac)2: Vanadyl acetylacetonate Fe: Iron(III) tris(2-ethylhexanoate) mineral spirit solution (Fe: 6% by mass) Cu: Copper(II) ethylhexanoate Co: Cobalt (II) 2-ethylhexanoate mineral spirit solution (Co: 12% by mass) Mn: Manganese (II) 2-ethylhexanoate mineral spirit solution (Mn: 8% by mass) (BuO)3PO: Tributyl phosphate

[0092] (1) Adhesion evaluation test [How to create a sample for adhesion evaluation test] A 30mm x 30mm substrate made of EPDM rubber or ACM rubber was prepared, washed with acetone, and dried. A primer composition was applied to the substrate, and then anaerobic adhesive A was applied to the center of the substrate in an area of ​​30mm x 5mm x 1mm. Since the adhesive surface was exposed in the samples prepared for this evaluation, anaerobic curing was difficult to proceed with, so UV curing was also used. Anaerobic adhesive A was cured by irradiating it with 3J / cm (300mW / cm) using an ECS-4011GX manufactured by iGraphics Co., Ltd.

[0093] [Adhesion test evaluation method] When the uncoated portion of the substrate was deformed 90 degrees toward the opposite side of the adhesive surface, the adhesive was evaluated as Good if it adhered well and did not peel off, Average if it partially peeled off, and Poor if it completely peeled off. Adhesion was good when V or Fe was used as the metal ion, but peeling occurred easily when Cu or Co was used, revealing that the adhesive did not adhere to the rubber. This tendency did not change even when an adhesion promoter (tributyl phosphate: (BuO)3PO) was used in the primer composition.

[0094] (2) Bonding adhesion test [How to prepare a bonding test sample] Two 30mm x 50mm substrates made of EPDM rubber or ACM rubber were prepared, washed with acetone, and dried. A primer composition was applied to one substrate. Anaerobic adhesive A was applied to the other substrate. The surface of one substrate coated with the primer composition and the surface of the other substrate coated with the anaerobic curing adhesive composition were bonded together, clamped with double clips, and left to cure for 24 hours. Using a Strograph 20-C manufactured by Toyo Seiki Co., Ltd., the sample was pulled in the shear direction at room temperature at 10 mm / min to measure the shear strength. The two samples were evaluated as Good if they were in good contact, Average if they were cured but easily peeled off, and Poor if they were uncured. Samples using V or Fe as metal ions were completely cured and did not peel off easily even when pulled in the shear direction. However, samples using Cu, Co, etc. peeled off immediately when pulled.

[0095] [Table 2]

Claims

1. A primer composition for rubber adhesion, comprising at least one metal selected from vanadium and iron.

2. The rubber adhesion primer composition according to claim 1, further comprising a phosphate ester compound.

3. 3. The primer composition for rubber adhesion according to claim 1, which is a primer composition for acrylic rubber or diene rubber.

4. A rubber adhesive comprising the primer composition for rubber bonding according to claim 1 or 2 and an anaerobic adhesive containing a radically polymerizable compound and an anaerobic curing catalyst.

5. An adhesive laminate in which a substrate (1) and a substrate (2) are bonded via an adhesive layer, At least one of the substrate (1) and the substrate (2) is rubber, The adhesive laminate comprises an adhesive layer containing a polymer of a radically polymerizable compound and at least one metal selected from vanadium and iron.

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