Primer composition

Abstract

The present invention relates to a primer composition that achieves excellent adhesion to poorly adhesive materials. Specifically, the present invention relates to a primer composition that includes (A) benzophenone, (B) a compound that has at least 2 benzene rings and a molecular weight of at least 190, and (C) a solvent.

Description

[Technical Field]

[0001] The present invention relates to a primer composition that improves adhesion to poorly adhesive materials. [Background technology]

[0002] Hard-to-bond materials (polyethylene, polypropylene, etc.) are chemically stable and have low surface polarity, making it difficult to use adhesives. However, in recent years, the use of hard-to-bond materials has increased in light of the need to reduce the weight of various parts and increase design freedom. Conventional bonding methods for hard-to-bond materials include surface modification (primer treatment, plasma treatment, corona treatment, ultraviolet treatment, ozone treatment, flame treatment), and among these, primer treatment is a very useful technique because it does not require dedicated equipment. It has long been known that surface modification is possible by using a hydrogen abstraction initiator in a primer treatment agent (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-336575 Summary of the Invention

[0004] However, it has been found that with conventional primer compositions using hydrogen abstraction initiators, if a long time passes between application of the primer composition to the adherend and irradiation with active energy rays, the adhesive strength-improving effect is gradually lost, and the duration of the primer effect is short. The duration of the effect in this invention refers to the time during which the adhesive strength-improving effect of the primer composition is maintained. Furthermore, conventional primers require the use of multiple types depending on the adhesive or sealant.

[0005] As a result of intensive research to solve the above problems, the present inventors have found a method for obtaining a primer composition that is excellent in the duration of its effect from application of the primer until irradiation with active energy rays, and that can improve adhesive strength regardless of the type of curing form of the adhesive or sealant used as the curable resin composition.

[0006] The present invention can be any of the following [1] to

[10] . Appropriate combinations of the specific elements described in [1] to

[10] are also within the scope of the present invention. [1] (A) Component: Benzophenone, (B) component: a compound having two or more benzene rings and a molecular weight of 190 or more, and (C) component: solvent, A primer composition comprising: [2] The component (B) is represented by the following general formula (1): TIFF0007753628000001.tif46105 (In formula (1), R 1 and R 2 are each independently a substituent selected from the group consisting of a hydrogen atom, a halogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted carboxyl group, a hydroxyl group, a nitrogen atom, and a sulfur atom; R 2 is the other R 2 may be directly bonded to, or indirectly bonded to via, a carbon atom, an oxygen atom, a sulfur atom, or a nitrogen atom The primer composition according to [1] above, wherein the compound has a structure represented by the formula: [3] The primer composition according to [1] or [2] above, wherein the component (B) is 0.1 to 20 parts by mass per 100 parts by mass of the component (A). [4] The primer composition according to any one of [1] to [3] above, wherein the component (C) is acetone or n-hexane. [5] The primer composition according to any one of [1] to [4] above, which is used for bonding difficult-to-bond materials. [6] (1): A step of applying the primer composition according to any one of [1] to [5] to the surface of an adherend; (2): A step of drying the applied primer composition; (3): A step of irradiating the dried primer composition with active energy rays to modify the surface of the adherend to which the primer composition has been applied; (4): A step of applying a curable resin composition to the surface of the modified adherend; and (5): A step of curing the applied curable resin composition to form a cured product of the curable resin composition on the surface of the adherend; A method for adhering adherends, comprising: [7] The bonding method according to [6] above, wherein the curable resin composition contains a compound having any one of a (meth)acryloyl group, an epoxy group, and a hydrolyzable silyl group. [8] The bonding method according to [6] or [7] above, wherein the adherend is polypropylene or polyethylene. [9] (1): A step of applying the primer composition according to any one of [1] to [5] to the surface of an adherend; (2): A step of drying the applied primer composition; and (3): A step of irradiating the dried primer composition with active energy rays to modify the surface of the adherend to which the primer composition has been applied; A method for modifying the surface of an adherend, comprising:

[10] An adherend having a surface modified by the modification method according to [9] above.

[0007] The primer composition of the present invention is extremely useful because it has a long duration of effect after application to an adherend and is not limited by the type of curing form of the adhesive or sealant used as the curable resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0008] The details of the present invention are described below. Note that the preferred and more preferred embodiments exemplified below can be used in appropriate combination with each other regardless of expressions such as "preferable" or "more preferred." Furthermore, the descriptions of numerical ranges are merely examples, and ranges obtained by appropriately combining the upper and lower limits of each range and the numerical values ​​of the examples can also be preferably used regardless of expressions such as "preferable" or "more preferred." Furthermore, terms such as "contain" or "comprise" may be interpreted as "essentially consisting of" or "consisting only of," as appropriate.

[0009] <Primer composition> One aspect of the present invention is a primer composition comprising component (A): benzophenone, component (B): a compound having two or more benzene rings and a molecular weight of 190 or more, and component (C): a solvent. [Component (A)] The component (A) used in the present invention is benzophenone. When exposed to active energy rays such as ultraviolet light, component (A) undergoes a triplet excited state and undergoes a hydrogen abstraction reaction, resulting in a remarkable improvement in adhesion to poorly adhesive materials such as polyolefins, such as polypropylene. The term "active energy rays" as used herein refers to radiation such as α-rays and β-rays, electromagnetic waves such as γ-rays and X-rays, electron beams (EB), ultraviolet rays of about 100 to 400 nm, and visible light of about 400 to 800 nm, with ultraviolet rays being preferred. When component (A) of the present invention is exposed to active energy rays, it abstracts hydrogen from the surface of an adherend such as a polyolefin, and the activated adherend reacts with the curable resin composition, improving adhesion at the adherend interface and affecting the adhesive properties of the adherend. The benzophenone in component (A) differs from component (B) described below in that it has a molecular weight of 182.2 and is represented by the formula (1) representing component (B), where R 1 and R 2 are compounds in which all are hydrogen.

[0010] [(B) Component] The component (B) used in the present invention is a compound having two or more, preferably two or three, benzene rings and a molecular weight of 190 or more, 200 or more, or 210 or more. By containing the component (B), the duration of the effect after primer application can be extended. From the viewpoint of improving adhesive strength and effect duration, the molecular weight of the component (B) is preferably 190 or more but less than 1,000, more preferably 190 or more but less than 500, particularly preferably 190 or more but less than 400, and most preferably 190 or more but less than 300.

[0011] From the viewpoint of compatibility with the component (A) when dissolved in the component (C) (solvent), the component (B) is preferably a compound having a structure represented by the following general formula (1): TIFF0007753628000002.tif46105 In formula (1), R 1 and R 2 are each independently a substituent selected from the group consisting of a hydrogen atom, a halogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted carboxyl group, a hydroxyl group, a nitrogen atom, and a sulfur atom; R 2 is the other R 2 It may be directly bonded to or indirectly bonded to via a carbon atom, an oxygen atom, a sulfur atom, or a nitrogen atom. 1 and R 2 R are each independently a substituent selected from the group consisting of a methyl group, an ethyl group, a methylamino group, an ethylamino group, a carboxyl group, a (meth)acryloyloxy group, and a hydroxyl group. 2 is the other R 2 It is also preferable that the component (A) and the component (B) are different from each other, and that all R in the general formula (1) are indirectly bonded to each other via an oxygen atom. 1 and R 2 cannot simultaneously be a hydrogen atom.

[0012] Specific examples of the component (B) include 2-methylbenzophenone, 3-methylbenzophenone, 2-ethylbenzophenone, 3-ethylbenzophenone, 4-methylbenzophenone, 4-ethylbenzophenone, 4-bromobenzophenone, 4-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4-chloro-4'-benzylbenzophenone, 4,4'-dimethoxybenzophenone, 3-methoxybenzophenone, 2,4,6-trimethylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 4-cyanobenzophenone, 4-methacryloyloxybenzophenone, 4-benzyl ...benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone, 4-benzylbenzophenone Examples of suitable benzoylbenzoic acid include benzoylbenzoic acid, 2,2,4,4-tetramethylbenzophenone, 4,4-dimethylbenzophenone, 4-dimethylaminobenzophenone, 2,4-dihydroxybenzophenone, 3,3,4,4-benzophenonetetracarboxylic dianhydride, 4-(dimethylamino)benzophenone, 2,4-dimethoxy-4'-hydroxybenzophenone, xanthone, 3-hydroxyxanthen-9-one, 9-hydroxyxanthene, thioxanthone, 2-isopropylthioxanthone, and 2,4-diethylthioxanthen-9-one, and sodium anthraquinone-2-sulfonate monohydrate. Among these, from the viewpoint of effect sustainability, that is, whether the effect of improving adhesion of the primer composition of the present invention can be maintained for a long period of time, 4-methacryloyloxybenzophenone, 2,2,4,4-tetramethylbenzophenone, 3,3,4,4-benzophenonetetracarboxylic acid dihydrate, 4,4-dimethylbenzophenone, 4-dimethylaminobenzophenone, xanthone, and 2,4-dihydroxybenzophenone are preferred.

[0013] The content of the component (B) is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, and most preferably 1 to 12 parts by mass, per 100 parts by mass of the component (A). When the content is 0.1 to 20 parts by mass, the adhesive strength of the curable resin composition when using the primer composition is excellent, and the deterioration of the adhesive strength improvement effect over time after application of the primer composition can be suppressed.

[0014] [(C) component] The component (C) used in the present invention is a solvent. It is not particularly limited as long as it can dissolve the components (A) and (B). However, from the viewpoint of drying properties after application of the primer composition, the vapor pressure at 25°C is preferably 5 mmHg or more but less than 400 mmHg, more preferably 50 mmHg or more but less than 350 mmHg, and most preferably 100 mmHg or more but less than 300 mmHg. A vapor pressure of 5 mmHg or more but less than 400 mmHg provides excellent surface wetting and spreading properties and drying properties after application, resulting in good workability. Specific examples of the component (C) include acetone, methyl acetate, ethyl acetate, methyl ethyl ketone, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monoisopropyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, n-heptane, n-octane, isooctane, methylcyclohexane, ethylcyclohexane, n-hexane, toluene, and xylene. From the viewpoints of compatibility with the components (A) and (B) and non-attack on the adherend, acetone, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and n-hexane are preferred, acetone, isopropyl alcohol, and n-hexane are more preferred, and acetone and n-hexane are most preferred.

[0015] The total content of the (A) component and the (B) component is preferably 1 to 20 parts by mass, more preferably 2 to 17 parts by mass, and most preferably 3 to 15 parts by mass, per 100 parts by mass of the (C) component. By having this total content be 1 to 20 parts by mass, the (A) component and the (B) component can be uniformly dissolved in the (C) component, and a primer composition that has excellent drying properties after application can be obtained.

[0016] [Optional ingredients] The primer composition of the present invention may contain additives such as fillers, colorants, plasticizers, coupling agents, leveling agents, and rheology control agents, as long as the properties of the present invention are not impaired. However, from the viewpoints of wettability to the surface of the adherend and applicability to various curable compositions, it is preferable that the primer composition contain no additives. Specific examples of fillers include organic powders, inorganic powders, and metallic powders. Examples of inorganic powder fillers include glass, alumina, mica, ceramics, silicone rubber powder, calcium carbonate, aluminum nitride, carbon powder, kaolin clay, dried clay minerals, and dried diatomaceous earth. The amount of inorganic powder blended is preferably about 0.1 to 100 parts by mass per 100 parts by mass of the total of components (A) and (B). If the amount is 100 parts by mass or less, sufficient fluidity as a primer composition is obtained, and good workability is achieved.

[0017] Examples of organic powder fillers include polyethylene, polypropylene, nylon, cross-linked acrylic, cross-linked polystyrene, polyester, polyvinyl alcohol, polyvinyl butyral, and polycarbonate. The amount of organic powder blended is preferably about 0.1 to 100 parts by mass per 100 parts by mass of the total of components (A) and (B). If the amount is more than 0.1 part by mass, the effect will not be diminished, and if it is 100 parts by mass or less, sufficient fluidity as a primer composition is obtained, and good workability is achieved.

[0018] Examples of metallic powder fillers include gold, platinum, silver, copper, indium, palladium, nickel, alumina, tin, iron, aluminum, and stainless steel. The amount of metallic powder blended is preferably about 0.1 to 100 parts by mass, and more preferably 1 to 50 parts by mass, per 100 parts by mass of the total of components (A) and (B).

[0019] The amount of optional components contained in the primer composition of the present invention is, for example, 0.05 to 100 parts by mass, preferably 0.1 to 50 parts by mass, and more preferably 0.2 to 20 parts by mass, per 100 parts by mass of the total of components (A) and (B).

[0020] [Primer] The primer referred to in the present invention, also known as an undercoat paint, is a base material applied prior to bonding and sealing various components (adherends) using a curable resin composition. It enhances the adhesion and adhesion between the adherend surface and the subsequently applied painted surface, thereby improving the adhesive strength of the curable resin composition in the present invention. The primer composition referred to in the present invention refers to a composition that has the characteristic of being interposed between an adherend, particularly a difficult-to-adhere component (difficult-to-adhere material), and thereby improving the adhesive strength of the curable resin composition in order to aid in the adhesion of the curable resin composition to the adherend. The primer composition itself has adhesive strength and can be bonded to particularly difficult-to-adhere components (difficult-to-adhere materials). Then, by curing the curable resin composition on the adherend surface modified with the primer composition, the adhesive strength between the cured product of the curable resin composition and the adherend can be improved.

[0021] <Adherend> The term "adherend" refers to a member to be bonded and / or sealed with the curable resin composition using the primer composition of the present invention. The adherend to which the primer composition of the present invention is applied is not particularly limited, but is preferably a poorly adhesive material. Specific examples of poorly adhesive materials in the present invention include polypropylene, polyethylene, polyacetal, polyethylene terephthalate, syndiotactic polystyrene, polyethylene naphthalate, polybutylene terephthalate, polyphenylene ether, polyphenylene sulfite, ethylene propylene diene rubber, liquid crystal polymer, cycloolefin polymer, polycarbonate, 6,6-nylon, polyamide, polyvinyl chloride, and silicone resin. Multiple adherends may be used, and if one is a poorly adhesive material, the other may be a material that is not poorly adhesive, such as acrylic resin, glass, wood, or metal.

[0022] The primer composition of the present invention exhibits its effect as a primer when used with a curable resin composition such as an adhesive or sealant.

[0023] <Curable resin composition> The curable resin composition used in the present invention refers to a composition that cures due to factors such as moisture, heat, and active energy, and can bond and / or seal adherends. The curing form of the curable resin composition is not particularly limited, and various curing forms such as moisture curing, anaerobic curing, heat curing, and active energy ray curing can be used. Of these, heat curing and active energy ray curing are preferred from the viewpoint of excellent adhesion durability.

[0024] The curable resin composition contains a compound having one or more of various functional groups depending on the curing form. Examples of functional groups include (meth)acryloyl groups, allyl groups, hydrosilyl groups, glycidyl groups, epoxy groups, hydrolyzable silyl groups, silanol groups, mercapto groups, amino groups, isocyanate groups, hydroxy groups, cyanate groups, acid anhydride groups, phenol groups, and isocyanurate groups. Among these, from the viewpoint of excellent adhesiveness, those containing a compound having two or more of the functional groups are preferred, and those containing a compound having functional groups such as (meth)acryloyl groups, allyl groups, glycidyl groups, epoxy groups, hydrolyzable silyl groups, and / or isocyanate groups are preferred.

[0025] Examples of the hydrolyzable silyl group include alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, methoxyethoxy, and ethoxyethoxy groups; acyloxy groups such as acetoxy, propionyloxy, butylcarbonyloxy, and benzoyloxy groups; alkenyloxy groups such as isopropenyloxy, isobutenyloxy, and 1-ethyl-2-methylvinyloxy groups; dimethylketoxime groups, methylethylketoxime groups, diethylketoxime groups, cyclopentyloxy groups, and the like. Examples of such groups include ketoxime groups such as anthranoxime group and cyclohexanoxime group; amino groups such as N-methylamino group, N-ethylamino group, N-propylamino group, N-butylamino group, N,N-dimethylamino group, N,N-diethylamino group and N-cyclohexylamino group; amide groups such as N-methylacetamide group, N-ethylacetamide group and N-methylbenzamide group; and aminooxy groups such as N,N-dimethylaminooxy group and N,N-diethylaminooxy group.

[0026] Specific examples of the heat-curable resin composition and active energy ray-curable resin composition include heat- or active energy ray-curable resin compositions containing a curable vinyl polymer, a curable polyether, a curable polyester, a curable polyurethane, a curable polyurea, a curable fluoropolymer, a curable polyorganosiloxane, and a curable epoxy.

[0027] The curable resin composition can be exemplified by compositions that can be used as various adhesives.For example, the heat-curable adhesive containing the curable vinyl polymer can be exemplified by compositions containing an acrylic polymer having an allyl group, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, a hydrosilyl compound, and a hydrosilylation catalyst; compositions containing an acrylic polymer having a (meth)acryloyl group, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, and a thermal radical initiator; compositions containing an acrylic polymer having a glycidyl group, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, and a thermal cationic initiator. Examples of active energy ray-curable adhesives containing the curable vinyl polymer include active energy ray-curable adhesives containing an acrylic polymer having (meth)acryloyl groups, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, and a photoradical initiator; active energy ray-curable adhesives containing a polyisobutylene polymer or polyacrylic having glycidyl groups and a photocationic initiator; and compositions containing an acrylic polymer having glycidyl groups, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, and a photocationic initiator. Examples of heat-curable adhesives containing the curable polyorganosiloxane include compositions containing a polyorganosiloxane having an allyl group, a hydrosilyl compound, and a hydrosilylation catalyst; compositions containing a polyorganosiloxane having (meth)acryloyl groups and a thermal radical initiator; and compositions containing a polyorganosiloxane having a glycidyl group and a thermal cationic initiator. Examples of the active energy ray-curable adhesive containing the curable polyorganosiloxane include a composition containing a polyorganosiloxane having an allyl group, a hydrosilyl compound, and a photoactive hydrosilylation catalyst; a composition containing a polyorganosiloxane having a (meth)acryloyl group, and a photoradical initiator;Examples include a composition containing a polyorganosiloxane having a glycidyl group and a photocationic initiator. Examples of heat-curable adhesives containing the curable epoxy include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AS-type epoxy resins, bisphenol AD-type epoxy resins, and tetrabromobisphenol A-type epoxy resins; hydrogenated bisphenol-type epoxy resins obtained by hydrogenating these bisphenol-type epoxy resins; oxazolidone-type epoxy resins obtained by reacting bisphenol A-type epoxy resins with bifunctional isocyanates; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,2-butanediol diglycidyl ether, 1,3-butanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, 2,3-butanediol diglycidyl ether, 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-cyclohexyl benzoate ...cyclohexyl benzoate diglycidyl ether, 1,6-cyclohexyl benzoate diglycidyl ether, 1,5-cyclohexyl benzoate diglycidyl ether, 1,5-cyclohexyl benzoate diglycidyl ether, 1,6-cyclohexyl benzoate diglycidyl ether, 1,5-cyclohexyl benzoate diglyc Alkylene glycol-type epoxy resins such as cyclohexanedimethanol diglycidyl ether; alkylene oxide diol-type epoxy resins such as diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether; novolac-type epoxy resins such as resorcinol diglycidyl ether, hydroquinone diglycidyl ether, 4,4'-dihydroxy-3,3',5,5'-tetramethylbiphenyl diglycidyl ether, diglycidyl ether of 1,6-dihydroxynaphthalene, diglycidyl ether of 9,9-bis(4-hydroxyphenyl)fluorene, diglycidyl aniline, biphenyl-type epoxy resins, naphthalene-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, and naphthol novolac-type epoxy resins;Examples of the composition include glycidyl ethers such as triglycidyl ether of tris(p-hydroxyphenyl)methane, tetraglycidyl ether of tetrakis(p-hydroxyphenyl)ethane, triglycidyl isocyanurate, triglycidyl ether of glycerin, and tetraglycidyl ether of pentaerythritol; and glycidyl amine compounds such as tetraglycidyldiaminodiphenylmethane, tetraglycidyl-m-xylylenediamine, triglycidyl-m-aminophenol, and triglycidyl-p-aminophenol.

[0028] The curable resin composition may contain a crosslinking agent, a catalyst, a curing agent, a colorant, a filler, a flame retardant, a diluent, a plasticizer, an antioxidant, an antifoaming agent, a coupling agent, a leveling agent, a rheology control agent, or the like, as long as the properties of the present invention are not impaired. Examples of the curing agent include aliphatic polyamine curing agents such as triethylenetetramine, N-aminoethylpiperazine, and xylenediamine; aromatic amine curing agents such as metaphenylenediamine and diaminodiphenylmethane; secondary or tertiary amine curing agents such as piperidine, N,N-dimethylpiperazine, and triethylenediamine; and imidazole curing agents such as 2-methylimidazole and 2-ethyl-4-methylimidazole. The amount of curing agent can be a commonly used amount, but it is appropriate to use 1 to 50 parts by mass, preferably 5 to 30 parts by mass, and more preferably 10 to 20 parts by mass of the curing agent per 100 parts by mass of the curable resin composition, such as a bisphenol A-type epoxy resin.

[0029] <How to use> The primer composition of the present invention can contribute to modifying the surface of an adherend and improving adhesion between a curable resin composition (or a cured product thereof) and an adherend through the following steps. Specifically, the primer composition of the present invention can be used in a method for modifying the surface of an adherend, which comprises the following steps (1) to (3), and a method for adhering an adherend, which comprises the following steps (1) to (5). (1): A step of applying the primer composition of the present invention to the surface of an adherend. (2): A step of drying the applied primer composition. (3) A step of irradiating the dried primer composition with active energy rays to modify the surface of the adherend to which the primer composition has been applied. (4): A step of applying a curable resin composition to the surface of the modified adherend. (5): A step of curing the applied curable resin composition to form a cured product of the curable resin composition on the surface of the adherend. It is desirable that steps (1) to (3) in the method for modifying the surface of an adherend, or steps (1) to (5) in the bonding method, are carried out in this order.

[0030] Since the primer composition of the present invention has an excellent effect duration between (2) and (3), it is possible to carry out each step with a time interval between them. For example, it is preferable that the effect is maintained even if the time between (2) and (3) is 30 minutes or more, 40 minutes or more, 50 minutes or more, or 60 minutes or more. The "method of adhering an adherend" referred to here includes not only simply adhering (coating) a curable resin composition (or a cured product thereof) onto the surface of an adherend, but also a case where two adherends are adhered using a curable resin composition. When two adherends are adhered using a curable resin composition, the adherends may be bonded together before or after step (4). When the above-mentioned adherend is bonded to another adherend before step (4), (4a): Two adherends are bonded together, and steps (1) to (3) are carried out so that the primer composition is applied to both ends of the two adherends at the bonded ends, followed by step (4) of applying a curable resin composition to the ends; or (4b): When steps (1) to (3) are performed so as to apply a primer composition to the surfaces where two adherends come into contact with each other, and then step (4) is performed in which the two adherends are fitted together and a curable resin composition is applied to the fitting portion of the adherends or the vicinity thereof, In addition, when the adherend is bonded to another adherend after step (4), the following can be exemplified: (4c) An example is a case where a curable resin composition is applied to the surface of the adherend modified in steps (1) to (3) (step (4)), and then a step of applying another adherend (which may or may not be modified with a primer composition) on top of the applied curable resin composition is performed, followed by the above step (5).

[0031] <Application method> The method for applying the primer composition of the present invention to the surface of the adherend in step (1) above can be the same as the method for applying known adhesives or sealants. For example, methods such as dispensing using an automatic applicator, spraying, inkjet printing, screen printing, gravure printing, dipping, spin coating, and brush coating can be used. From the viewpoint of coatability, the primer composition of the present invention is preferably liquid at 25°C. When the adherend is in sheet form, the primer composition may be applied to one or both surfaces of the adherend. When the adherend has a three-dimensional shape, the primer composition may be applied to a part or all of the surfaces of the adherend.

[0032] <Drying step of primer composition> After applying the primer composition of the present invention in step (2) above, a drying step is preferably carried out. The ambient temperature in the drying step is preferably 100°C or lower, more preferably 50°C or lower, and most preferably drying at room temperature. From the viewpoints of wetting and spreading properties on the adherend and workability, the drying time is preferably 0.1 seconds to 3 hours, more preferably 1 second to 2 hours, and most preferably 5 seconds to 1 hour.

[0033] <Activated energy ray irradiation conditions> In the above step (3), the primer composition of the present invention is modified by irradiating it with active energy rays or the like after drying. When the surface modification method is active energy rays, the light source of the active energy rays, such as ultraviolet rays and visible light, is not particularly limited, and for example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LEDs, fluorescent lamps, sunlight, electron beam irradiation devices, etc. can be used. The irradiation dose of the active energy rays is preferably 10 kJ / m 2 More preferably, 15 kJ / m 2 There is no particular upper limit, but considering the impact on the components, it is set to 50 kJ / m 2 The following is preferred:

[0034] <Method for applying curable resin composition> After the surface of the substrate is modified using the primer composition of the present invention, a known method can be used to apply the curable resin composition to the modified surface of the substrate in step (4). For example, methods such as dispensing using an automatic coater, spraying, inkjet printing, screen printing, gravure printing, dipping, and spin coating can be used. From the viewpoint of coatability, the curable resin composition of the present invention is preferably liquid at 25°C.

[0035] <Method for curing curable resin composition> In the above step (5), the curing method of the curable resin composition applied to the surface of the adherend can be set under any conditions depending on the curing form of the curable resin composition. For example, in the case of a heat-curable resin composition, curing is preferably performed at 50°C to 300°C, more preferably at 70°C to 200°C. The curing time for heat curing is preferably 0.1 to 200 minutes, more preferably 1 to 100 minutes. In the case of an active energy ray-curable resin composition, the light source of the active energy ray, such as ultraviolet light or visible light, is not particularly limited, and examples that can be used include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LEDs, fluorescent lamps, sunlight, and electron beam irradiation devices. The irradiation dose of the active energy ray is 5 to 50 kJ / m 2 is preferred, and 7 to 40 kJ / m 2 is more preferable. In the case of a moisture-curable resin composition, it is preferably cured at 10 to 50°C, and the humidity is preferably 30 to 80%. In the case of moisture curing, the curing time is preferably 1 day to 2 weeks, more preferably 3 days to 1 week. By the above curing method, a cured product of the curable resin composition is formed on the surface of the adherend modified with the primer composition.

[0036] <Surface-modified adherends and laminates> As a result of the above step (3), a surface-modified adherend consisting of [adherend]-[primer composition (cured product of the primer composition after drying and irradiated with active energy rays)] can be obtained, and as a result of step (5), a laminate consisting of [adherend]-[primer composition (cured product of the primer composition after drying and irradiated with active energy rays)]-[cured product of the curable resin composition] can be obtained. The surface-modified adherend is composed of an adherend and a primer coating (cured product of the primer composition) obtained by drying a primer composition on the surface of the adherend and irradiating it with active energy rays. Without being bound by theory, it is believed that when the components of the primer composition other than the solvent, particularly component (A), are exposed to active energy rays, hydrogen is abstracted from the surface of the adherend, such as a polyolefin, generating radicals, activating the surface. It is impractical to analyze the physical and chemical state of an adherend with a modified surface; therefore, it is more practical to express and identify the surface condition using a surface modification method such as steps (1) to (3) above. The laminate obtained by further applying a curable resin composition to the surface of the surface-modified adherend and curing the composition has a structure in which a cured product of the curable resin composition is adhered to the surface of the surface-modified adherend. Due to the presence of the primer coating obtained by drying and irradiating with active energy rays, the cured product of the curable resin composition can be laminated with sufficient adhesive strength and cohesion to the adherend, even if the adherend is made of a poorly adhesive material.

[0037] <Applications and fields of use> Specific applications of the primer composition of the present invention and specific fields of use of the adhesion method include adhesive applications such as adhesives, sealing, casting, coatings, etc. for automotive switches, headlamps, internal engine parts, electrical components, drive engines, brake oil tanks, front hoods, fenders, body panels such as doors, windows, body frames, etc., and the automotive and transportation fields to which these belong; adhesive applications such as adhesives, sealing, casting, coatings, etc. for flat panel displays (liquid crystal displays, organic EL displays, light-emitting diode displays, field emission displays), video discs, CDs, DVDs, MDs, pickup lenses, hard disks, etc., and the electronic materials fields to which these belong; adhesive applications such as adhesives, sealing, casting, coatings, etc. for lithium batteries, lithium ion batteries, manganese batteries, alkaline batteries, fuel cells, silicon solar cells, color Applications include bonding, sealing, coating, etc. for dye-sensitized batteries, organic solar cells, etc., and the battery field to which these belong; applications include bonding, sealing, coating, etc. for optical fiber materials, optical passive components, optical circuit components, and optoelectronic integrated circuits in the areas surrounding optical switches and optical connectors, and the optical components field to which these belong; applications include bonding, sealing, coating, etc. for camera modules, lens materials, viewfinder prisms, target prisms, viewfinder covers, light-receiving sensor parts, photographic lenses, our company's lenses for projection TVs, etc., and the optical equipment field to which these belong; applications include bonding, sealing, coating, etc. for syringe needles and needle hubs, tubes and connectors, and fastening parts for cocks and pipes, etc., and the medical field to which these belong; applications include bonding, lining, sealing, coating, etc. for gas pipes, water pipes, etc., and the infrastructure field to which these belong.

[0038] Resins used in the automotive and transportation fields include, for example, polypropylene, polyethylene, polyurethane, ABS, phenolic resin, CFRP (carbon fiber reinforced plastic), GFRP (glass fiber reinforced plastic), 6,6-nylon, PPS, PBT, etc. In the present invention, such members are used as adherends, and the surface of the adherend can be modified with a primer composition in order to improve adhesion to the adherend surface in advance. [Example]

[0039] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0040] [Examples 1 to 8, Comparative Examples 1 to 5] The following ingredients were prepared to prepare the composition:

[0041] Component (A) (A): Benzophenone, molecular weight 182.2 (B) Component (B-1): 4-methacryloyloxybenzophenone, molecular weight 266.3 (B-2): 2,2,4,4-tetramethylbenzophenone, molecular weight 238.3 (B-3): 3,3,4,4-benzophenonetetracarboxylic dianhydride, molecular weight 322.2 (B-4): 4,4-dimethylbenzophenone, molecular weight 210.3 (B-5): 4-dimethylaminobenzophenone, molecular weight 225.3 (B-6): Xanthone, molecular weight 196.2 (B-7): 2,4-dihydroxybenzophenone, molecular weight 214.2 (B) Comparative ingredients (B'-1): o-Acetoacetanisidide, molecular weight 207.2 (B'-2): 4,4-dimethylbiphenyl, molecular weight 182.3 (C) Component (C-1): Acetone vapor pressure (25°C) 231.06 mmHg (C-2): n-Hexane Vapor pressure (25°C) 150mmHg

[0042] The component (C) was weighed into a stirring vessel, and the components (A) and (B) were added, followed by stirring for 10 minutes with a mixer. The detailed amounts prepared are shown in Tables 1 and 2, and all values ​​are expressed in parts by mass. All tests were carried out at room temperature (25°C).

[0043] [Shear adhesive strength test] In this example, the shear bond strength test was performed based on the tensile shear bond strength test of JIS K 6850 1999, by bonding the adherends together, applying a tensile load in the thickness direction of the adherends perpendicular to the bonding surface, and measuring the tensile shear bond strength.

[0044] [Shear adhesive strength / Condition 1] Two test pieces (made of polypropylene, width 25 mm × thickness 1.5 mm × length 100 mm) were prepared as adherends, and each primer composition of Examples 1 to 8 and Comparative Examples 1 to 5 was applied to one surface of each test piece using a waste cloth, and the surface was left to stand at room temperature for 30 seconds to dry the solvent (C). The surface to which the primer composition had been applied was irradiated with ultraviolet light (30 kJ / m) from a high-pressure mercury lamp. 2 ) was performed to modify the surface. A curable resin composition (a 100:13 mixture of bisphenol A epoxy resin and triethylenetetramine) was applied to the modified surface of one test piece over an area 25 mm wide and 10 mm long, and the modified surface of the other test piece was attached to the coated surface. The coated surface was then cured in a hot air oven at 100°C for 1 hour. After curing, the test piece was returned to room temperature, and measurements were performed using a tensile tester at a speed of 50 mm / min based on the shear bond strength test described above. Condition 1 passing criteria: 4 MPa or more [Shear adhesive strength / Condition 2] Two test pieces (made of polypropylene, width 25 mm × thickness 1.5 mm × length 100 mm) were prepared as adherends, and each primer composition of Examples 1 to 8 and Comparative Examples 1 to 5 was applied to one surface of each test piece using a waste cloth, and the test piece was left to stand at room temperature for 30 seconds to dry the solvent (C), and then the test piece was left to stand at 25°C for 60 minutes. The surface to which the primer composition had been applied was irradiated with ultraviolet light (30 kJ / m) from a high-pressure mercury lamp. 2 ) was performed to modify the surface. A curable resin composition (a 100:13 mixture of bisphenol A epoxy resin and triethylenetetramine) was applied to the modified surface of one test piece over an area 25 mm wide and 10 mm long, and the modified surface of the other test piece was attached to the coated surface. The coated surface was then cured in a hot air oven at 100°C for 1 hour. After curing, the test piece was returned to room temperature, and measurements were performed using a tensile tester at a speed of 50 mm / min based on the shear bond strength test described above. Criterion for passing condition 2: 4 MPa or more Acceptance criteria based on conditions 1 and 2: [shear bond strength under condition 2] - [shear bond strength under condition 1] = less than 1.0 MPa The shear bond strength was 0.5 MPa when the primer composition of the present invention was not used. The shear bond strength in this case was measured in the same manner as in Condition 1 above, except that no primer composition was used. Specifically, a curable resin composition (a mixture of bisphenol A epoxy resin and triethylenetetramine in a ratio of 100:13) was applied to the surface of one test piece (made of polypropylene, 25 mm wide x 1.5 mm thick x 100 mm long) over an area of ​​25 mm wide x 10 mm long. The surface of the other test piece was then bonded to the other test piece, and the resulting mixture was cured in a hot air oven at 100°C for 1 hour. The cured test piece was then returned to room temperature, and measurements were performed using a tensile tester at a rate of 50 mm / min based on the shear bond strength test described above (hereinafter referred to as Condition 3).

[0045] [Table 1] TIFF0007753628000003.tif72158

[0046] [Table 2] TIFF0007753628000004.tif83139

[0047] As shown in Table 1, by using component (B), adhesive strength does not decrease even after time has passed since application of the primer composition. As shown in Comparative Example 1 in Table 2, when component (B) was not used, adhesive strength decreased after 60 minutes. Furthermore, as shown in Comparative Example 2, when component (A) was omitted, adhesive strength under condition 1 was low. Furthermore, as shown in Comparative Examples 3 and 4, no effect was observed even when a compound that does not correspond to component (B) was used. In Comparative Example 5, the amount of component (A) was increased and component (B) was omitted, but no effect was obtained. Furthermore, the shear adhesive strength under condition 3 when no primer composition was used was 0.5 MPa, indicating that adhesive strength was significantly improved by the primer composition of the present invention.

[0048] <Use of primer composition in active energy ray-curable resin composition> Two test pieces (made of polypropylene, width 25 mm × thickness 1.5 mm × length 100 mm) were prepared as adherends, and the primer composition of Example 1 was applied to one side of each test piece using a waste cloth. The test pieces were then left to stand at room temperature for 60 minutes to dry the solvent (C). An active energy ray-curable resin composition (ThreeBond 3094, manufactured by ThreeBond Co., Ltd.) containing a compound having two or more (meth)acryloyl groups was applied to the modified surface of one of the test pieces over an area of ​​25 mm wide × 10 mm long, and the other test piece (made of polyethylene, width 25 mm × thickness 1.5 mm × length 100 mm) was attached to the modified surface. The resulting mixture was then irradiated with 30 kJ / m irradiated with a high-pressure mercury lamp. 2 The cured test piece was subjected to shear bond strength testing at a speed of 50 mm / min using a tensile tester in accordance with the above-described shear bond strength test, and the shear bond strength was found to be 6.4 MPa. The shear bond strength under condition 3, in which no primer composition was used, was 0.9 MPa, indicating that the use of the primer composition of the present invention can significantly improve adhesive strength.

[0049] <Use of primer composition in moisture-curable resin composition> Two test pieces (made of polypropylene, width 25 mm x thickness 1.5 mm x length 100 mm) were prepared as adherends. The primer composition of Example 1 was applied to one side of each test piece using a rag, and the test pieces were left at room temperature for 60 minutes to dry the solvent (C). A moisture-curing resin composition (ThreeBond 1217G manufactured by ThreeBond Co., Ltd.) containing a compound having two or more hydrolyzable silyl groups was applied to the modified surface of one test piece over an area of ​​25 mm wide x 10 mm long. The other test piece (made of polyethylene, width 25 mm x thickness 1.5 mm x length 100 mm) was then bonded to the other test piece and cured at 25 °C x 55% RH x 1 week. The shear bond strength of the cured test piece was measured using a tensile tester at a speed of 50 mm / min based on the above-mentioned shear bond strength test, and was found to be 2.0 MPa. The shear bond strength under condition 3 without the primer composition was 0.2 MPa, demonstrating that the use of the primer composition of the present invention can significantly improve adhesion. [Industrial Applicability]

[0050] The primer composition of the present invention is extremely useful in industry because it can improve the adhesive strength of difficult-to-adhere materials regardless of the type of curing form of the adhesive and has an excellent durability of the effect.

Claims

1. (A) component: benzophenone, Component (B): a compound having two or more benzene rings and a molecular weight of 190 or more, and (C) component: solvent, and does not contain a curable resin, 1. A primer composition comprising: The component (B) is represented by the following general formula (1): (In formula (1), R 1 and R 2 are each independently a substituent selected from the group consisting of a hydrogen atom, a halogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted carboxyl group, a hydroxyl group, a nitrogen atom, and a sulfur atom; R 2 is the other R 2 may be directly bonded to, or indirectly bonded to via, a carbon atom, an oxygen atom, a sulfur atom, or a nitrogen atom is a compound having a structure represented by The amount of the component (B) is 0.1 to 20 parts by mass per 100 parts by mass of the component (A), Primer composition.

2. (A) component: benzophenone, Component (B): a compound having two or more benzene rings and a molecular weight of 190 or more, and (C) component: solvent, A primer composition consisting of only The component (B) is represented by the following general formula (1): (In formula (1), R 1 and R 2 are each independently a substituent selected from the group consisting of a hydrogen atom, a halogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted carboxyl group, a hydroxyl group, a nitrogen atom, and a sulfur atom; R 2 is the other R 2 may be directly bonded to, or indirectly bonded to via, a carbon atom, an oxygen atom, a sulfur atom, or a nitrogen atom is a compound having a structure represented by The amount of the component (B) is 0.1 to 20 parts by mass per 100 parts by mass of the component (A), Primer composition.

3. 3. The primer composition according to claim 1, wherein the amount of the component (B) is 0.5 to 15 parts by mass per 100 parts by mass of the component (A).

4. The primer composition according to any one of claims 1 to 3, wherein the component (C) is acetone or n-hexane.

5. The primer composition according to any one of claims 1 to 4, which is used for bonding a poorly adhesive material selected from polypropylene, polyethylene, polyacetal, polyethylene terephthalate, syndiotactic polystyrene, polyethylene naphthalate, polybutylene terephthalate, polyphenylene ether, polyphenylene sulfite, ethylene propylene diene rubber, liquid crystal polymer, cycloolefin polymer, polycarbonate, 6,6-nylon, polyamide, polyvinyl chloride, and silicone resin.

6. (1): A step of applying the primer composition according to any one of claims 1 to 5 to the surface of an adherend; (2): A step of drying the applied primer composition; (3): A step of irradiating the dried primer composition with active energy rays to modify the surface of the adherend to which the primer composition has been applied; (4): A step of applying a curable resin composition to the surface of the modified adherend; and (5): A step of curing the applied curable resin composition to form a cured product of the curable resin composition on the surface of the adherend; A method for adhering adherends, comprising:

7. The bonding method according to claim 6 , wherein the curable resin composition contains a compound having any one of a (meth)acryloyl group, an epoxy group, and a hydrolyzable silyl group.

8. 8. The bonding method according to claim 6, wherein the adherend is polypropylene or polyethylene.

9. (1): A step of applying the primer composition according to any one of claims 1 to 5 to the surface of an adherend; (2): A step of drying the applied primer composition; and (3): A step of irradiating the dried primer composition with active energy rays to modify the surface of the adherend to which the primer composition has been applied; A method for modifying the surface of an adherend, comprising:

10. An adherend having a surface modified by the modification method according to claim 9.

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