adhesive composition

Abstract

To provide an adhesive composition exhibiting suitable performance for use as an adhesive composition and enabling formation of a flame-retardant adhesive cured product.SOLUTION: An adhesive composition comprises a first agent containing an organic peroxide and a second agent containing a reducing agent, wherein each of (a) a monofunctional (meth)acrylic monomer, (b) (meth)acrylic acid and / or hydroxyalkyl (meth)acrylate, and (c) a thickener is contained in at least one of the first agent and the second agent, and at least one of the first agent and the second agent further contains a reactive flame retardant.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to adhesive compositions. In particular, the present disclosure relates to two-part acrylic adhesive compositions. [Background technology]

[0002] BACKGROUND ART Two-component acrylic adhesives have been known as two-component reactive adhesives that harden in a short time at room temperature and bond materials together (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-156992 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, adhesive compositions capable of forming a cured product exhibiting flame retardancy have not been given much importance because the proportion of the cured product of the adhesive composition in the bonded product is small. On the other hand, in recent years, adhesive compositions capable of forming a cured product exhibiting flame retardancy have been required in some cases for products requiring a high level of flame retardancy.

[0005] Conventionally, a flame retardant has been added to a composition as a means for imparting flame retardancy to the composition. For example, additive-type phosphorus-based flame retardants, which exhibit flame retardancy by forming a carbonized layer in the solid phase, are widely used as flame retardants. Generally, flame retardancy improves with an increase in the amount of flame retardant added, but an increase in the amount of flame retardant added can also reduce the performance of the adhesive composition (e.g., adhesive strength and stability of the adhesive composition). Therefore, there is a demand for an adhesive composition that can produce a cured product that exhibits flame retardancy and has suitable performance as an adhesive composition.

[0006] The present disclosure has been made in view of the above problems. That is, a main object of the present disclosure is to provide an adhesive composition that has suitable performance as an adhesive composition and is capable of forming a flame-retardant cured adhesive product. [Means for solving the problem]

[0007] In order to achieve the above object, the present disclosure provides a coating composition comprising a first agent containing an organic peroxide and a second agent containing a reducing agent, (a) monofunctional (meth)acrylic monomers; (b) (meth)acrylic acid and / or hydroxyalkyl (meth)acrylate; and (c) Thickener each of which is contained in at least one of the first agent and the second agent, There is provided an adhesive composition, wherein at least one of the first part and the second part further comprises a reactive flame retardant. [Effects of the Invention]

[0008] The adhesive composition according to the present disclosure has suitable properties as an adhesive composition and is capable of forming a flame-retardant cured adhesive product. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail.

[0010] The features or benefits of the present disclosure are illustrated by reference to preferred embodiments. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present disclosure. It should be understood that other embodiments may also be utilized, and that modifications may be made without departing from the scope of the present disclosure. Although the embodiments may be illustrated separately for convenience, partial substitution or combination of the features illustrated in different embodiments is possible. Therefore, the present disclosure is not expressly limited to the preferred embodiments (alone or in combination with other features) that illustrate non-limiting combinations of possible features. In the embodiments described below, descriptions of commonalities with the previous embodiments will be omitted, and only differences will be described. In particular, similar actions and effects resulting from similar configurations will not be mentioned in each embodiment.

[0011] The adhesive composition of the present disclosure may be a so-called second-generation acrylic adhesive (SGA), which undergoes reactive curing by mixing a peroxide and its decomposition accelerator (reducing agent). Specifically, the adhesive composition contains a first and second part, respectively, containing a radical-generating peroxide and a reducing agent that reacts with the peroxide. Upon use, the first and second parts are brought into contact with each other to initiate a radical reaction, polymerizing the polymerizable (meth)acrylic monomer contained in the first and / or second parts. Such SGAs primarily include two-part main component acrylic adhesives, main component-primer acrylic adhesives, and main component-curing agent acrylic adhesives. Two-part main component acrylic adhesives contain a first part containing a peroxide and a second part containing a reducing agent, with both the first and second parts containing polymerizable (meth)acrylic monomers. In the case of base-primer type acrylic adhesives and base-curing agent type acrylic adhesives, either the first or second part contains a polymerizable (meth)acrylic monomer, and the other functions as a primer liquid or a curing agent. As described in detail below, the adhesive composition of the present disclosure may be either a two-part base type or a base-primer type. In this specification, (meth)acrylic means acrylic or methacrylic.

[0012] The adhesive composition of the present disclosure comprises a first part containing an organic peroxide and a second part containing a reducing agent. At least one of the first and second parts further comprises a (meth)acrylic monomer as component (a), (meth)acrylic acid and / or a hydroxyalkyl (meth)acrylate as component (b), and a thickener as component (c). A feature of the adhesive composition of the present disclosure relates to the fact that at least one of the first and second parts having such a composition further comprises a reactive flame retardant.

[0013] Generally, a flame retardant refers to a material that has the effect of making flammable materials such as resins less flammable. Such flame retardants are broadly classified into inorganic flame retardants, halogen-based flame retardants, and phosphorus-based flame retardants. Among these, additive-type phosphorus-based flame retardants are widely used as phosphorus-based flame retardants. Here, "additive-type" refers to a flame retardant that is blended into a composition and exists in a state that is not chemically bonded to other components.

[0014] The present inventors have discovered that the use of additive-type flame retardants to impart flame retardancy to adhesive compositions poses several challenges. Specifically, the addition of additive-type flame retardants can reduce the adhesive strength of the adhesive composition. Furthermore, insufficient compatibility with resins can lead to separation and precipitation of components contained in the adhesive composition, potentially reducing the storage stability of the adhesive composition. Furthermore, when additive-type flame retardants are used, the flame retardant is physically mixed into the adhesive composition, which can result in uneven distribution of the flame retardant depending on the degree of mixing between the first and second parts. This can lead to variations in the flame retardancy of the adhesive cured product (hereinafter simply referred to as the "cured product") obtained from the adhesive composition, reducing the reproducibility of the flame retardancy of the cured product. Furthermore, adhesives containing additive-type flame retardants can suffer from a bleed-out phenomenon, in which low-molecular-weight phosphorus compounds leak from the surface of the adhesive composition into the atmosphere over time, potentially posing a health hazard.

[0015] The present inventors have newly discovered that the use of a reactive flame retardant can address the problems encountered when using the above-mentioned additive flame retardants. In this specification, a reactive flame retardant refers to a compound that has a reactive group capable of reacting with at least one compound contained in a material to which the reactive flame retardant is added, thereby imparting flame retardancy to the material. In other words, the reactive flame retardant introduces the flame retardant skeleton into a polymer by chemically bonding with at least one component contained in the adhesive composition. After extensive research, the present inventors have discovered that adding a reactive flame retardant to an adhesive composition containing at least a (meth)acrylic monomer (component (a)), (meth)acrylic acid and / or a hydroxyalkyl (meth)acrylate (component (b)), and a thickener (component (c)) results in the introduction of the flame retardant skeleton into the polymer backbone in the cured product of the adhesive composition obtained by copolymerization induced by mixing the first and second components. Because reactive flame retardants are incorporated into the resin skeleton molecules of the adhesive composition, they can have better compatibility with the adhesive composition than additive-type flame retardants. Furthermore, because the flame retardant chemically bonds with the components of the adhesive composition, the occurrence of bleed-out can also be suppressed. Furthermore, it has been newly discovered that the use of reactive flame retardants allows for the production of cured products with suitable flame retardancy at lower concentrations than when additive-type flame retardants are used.

[0016] In consideration of environmental impact, the reactive flame retardant used in the adhesive composition of the present disclosure is preferably a non-halogen-based reactive flame retardant that does not contain a halogen. For example, the reactive flame retardant may be a phosphorus-based reactive flame retardant that has a phosphorus atom in the molecule. When a phosphorus-based reactive flame retardant is used, it may be possible to impart suitable flame retardancy to the adhesive composition with a small content, thereby imparting flame retardancy to the cured product without excessively reducing the adhesive strength of the adhesive composition.

[0017] The reactive flame retardant may have at least one polymerizable unsaturated group as a reactive group that chemically reacts with the components of the adhesive composition. When the reactive flame retardant has a polymerizable unsaturated group, the (meth)acrylic monomer, (meth)acrylic acid and / or hydroxyalkyl (meth)acrylate contained in the adhesive composition are copolymerized with the reactive flame retardant, and the molecular skeleton of the reactive flame retardant is introduced into the polymer main chain in the cured product of the adhesive composition. In other words, by using the adhesive composition of the present disclosure, a flame-retardant cured product can be obtained as a flame-retardant polymer copolymerized with the reactive flame retardant.

[0018] For example, the polymerizable unsaturated group can be a vinyl group, an acrylic group, or a methacrylic group. The reactive flame retardant may include at least one functional group selected from the group consisting of a vinyl group, an acrylic group, or a methacrylic group.

[0019] For example, the reactive flame retardant used in the adhesive composition of the present disclosure can be a compound represented by the following general formula (I): [ka] In the formula, R1 is a reactive group capable of chemically bonding with a (meth)acrylic monomer contained in the adhesive composition, and is preferably a polymerizable unsaturated group. R2 and R3 each independently represent an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, or an aryl group having 6 to 14 carbon atoms.

[0020] The polymerizable unsaturated group R1 can be, for example, a vinyl group, an acrylic group, or a methacrylic group.

[0021] The alkyl group may be a straight-chain or branched alkyl group. The number of carbon atoms in the alkyl group may be, for example, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Although merely exemplary, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group.

[0022] The alkoxy group may be a linear or branched alkoxy group. The number of carbon atoms in the alkoxy group may be, for example, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Although merely exemplary, examples of the alkoxy group include a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, a pentyloxy group, and a hexyloxy group.

[0023] The number of carbon atoms in the aryl group may be, for example, 6 to 14, 6 to 10, or 6 to 8. The aryl group may be, for example, a substituted or unsubstituted phenyl group. The substituent on the phenyl group may be, for example, a linear or branched alkyl group. The number of carbon atoms in the alkyl group may be, for example, 1 to 8. Although merely exemplary, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, a heptyl group, and an octyl group. For example, the aryl group may be a phenyl group.

[0024] When a high phosphorus content in a reactive flame retardant is important, the functional groups R2 and R3 in the phosphorus-based reactive flame retardant represented by general formula (1) are particularly preferably alkyl groups having 1 to 3 carbon atoms or alkoxy groups having 1 to 3 carbon atoms, which have a smaller number of molecules. By using such a reactive flame retardant, an adhesive composition capable of forming a cured product exhibiting favorable flame retardancy can be obtained by incorporating a small amount of the reactive flame retardant. A small amount of the reactive flame retardant in the adhesive composition allows the adhesive composition to contain higher proportions of components that contribute to adhesion, such as (meth)acrylate monomers and (meth)acrylic acid and / or hydroxyalkyl (meth)acrylates. This reduces the deterioration of adhesive performance due to the inclusion of a flame retardant. Therefore, according to the present disclosure, an adhesive composition capable of forming a flame-retardant solidified product while maintaining favorable adhesive strength can be obtained.

[0025] As the reactive flame retardant, commercially available reactive flame retardants may be used. Specific reactive flame retardants having a vinyl group as a reactive group include, for example, dimethyl vinyl phosphonate (VHP-1, manufactured by Koatsu Gas Kogyo Co., Ltd.), diethyl vinyl phosphonate (VHP-2, manufactured by Koatsu Gas Kogyo Co., Ltd.), diphenyl vinyl phosphonate (VHP-3, manufactured by Koatsu Gas Kogyo Co., Ltd.), and diphenyl vinyl phosphine oxide (VHP-4, manufactured by Koatsu Gas Kogyo Co., Ltd.). Specific reactive flame retardants having a methacrylic group as a reactive group include, for example, diethoxyphosphinylmethyl methacrylate (MC-2, manufactured by Katayama Chemical Industry Co., Ltd.) and diphenylphosphinylmethyl methacrylate (MC-4, manufactured by Katayama Chemical Industry Co., Ltd.).

[0026] The reactive flame retardant contained in the adhesive composition of the present disclosure may be a single type, or may be a combination of two or more different reactive flame retardants. For example, at least one of the first and second parts may contain a single reactive flame retardant, or may contain a combination of two or more different reactive flame retardants. Furthermore, when both the first and second parts contain a reactive flame retardant, the reactive flame retardants contained in each of the first and second parts may be the same, or may contain different reactive flame retardants.

[0027] The total content of the reactive flame retardants contained in the first and second parts of the adhesive composition is preferably 7 to 50 parts by weight, and more preferably 7 to 30 parts by weight, per 100 parts by weight of the total of (a) (meth)acrylic monomer, (b) (meth)acrylic acid and / or hydroxyalkyl (meth)acrylate, and (c) thickener contained in the first and second parts. For example, when the total content of the reactive flame retardants is 7 parts by weight or more per 100 parts by weight of the total of components (a), (b), and (c), the cured product obtained by curing the adhesive composition can exhibit more favorable flame retardancy. Furthermore, when the total content of the reactive flame retardants is 50 parts by weight or less per 100 parts by weight of the total of components (a), (b), and (c), the adhesive composition can more favorably maintain its performance, such as its adhesive strength.

[0028] The reactive flame retardant is contained in at least one of the first and second parts. For example, in the case of a two-part adhesive composition, the reactive flame retardant may be contained in only one of the first and second parts, or in both the first and second parts. When it is important to suppress a decrease in the content of components other than the reactive flame retardant contained in each of the first and second parts, it is more preferable that the reactive flame retardant be contained in both the first and second parts. This more effectively suppresses a decrease in adhesive strength due to the addition of the flame retardant, allowing the adhesive composition to exhibit more favorable adhesive performance. Furthermore, it is more preferable that the reactive flame retardant be contained in approximately the same amount in the first and second parts. This allows the reactive flame retardant to be more uniformly distributed when the first and second parts are mixed.

[0029] Alternatively, the reactive flame retardant may be contained in either the first or second part. For example, in a base-primer type or base-cure type adhesive composition, the reactive flame retardant may be contained only in the base part.

[0030] In the adhesive composition of the present disclosure, a cured product of the adhesive composition exhibiting favorable flame retardancy can be obtained by including a small amount of reactive flame retardant. The small amount of reactive flame retardant does not excessively reduce the content of other components in the adhesive composition, thereby more favorably maintaining the performance of the adhesive composition, such as adhesive strength. For example, when the reactive flame retardant is a phosphorus-based reactive flame retardant, the phosphorus content derived from the reactive flame retardant contained in the first and second parts constituting the adhesive composition can be, for example, 0.5 wt % to 5 wt %, 0.7 wt % to 4 wt %, or 1 wt % to 3 wt %.

[0031] In one embodiment, the adhesive composition of the present disclosure may be free of additive flame retardants. Specifically, additive flame retardants may be added to neither the first nor second parts of the adhesive composition. In such an embodiment, the adhesive composition of the present disclosure may also be considered an additive-flame retardant-free flame retardant adhesive composition. However, trace amounts of additive flame retardants unavoidably or accidentally mixed in during the manufacturing process or use of the adhesive composition may be acceptable. For example, it may be acceptable for such unavoidable or accidental additive flame retardants to be present in an amount of 0.01 wt % or less of the adhesive composition, as long as the desired effects of the present disclosure are achieved.

[0032] As described above, the adhesive composition of the present disclosure contains at least (a) a (meth)acrylic monomer, (b) (meth)acrylic acid and / or a hydroxyalkyl (meth)acrylate, and (c) a thickener as components contributing to adhesion. When the adhesive composition is a two-part main component type, components (a), (b), and (c) are contained in both the first and second components. On the other hand, when the adhesive composition is a main component-primer type or a main component-curing agent type, components (a), (b), and (c) are contained in either the first or second component. That is, when the adhesive composition is a main component-primer type or a main component-curing agent type, either the first or second component is a main component containing at least components (a), (b), and (c), and the other is a primer or a curing agent. For example, components (a), (b), and (c) may be contained in a first component containing an organic peroxide. That is, the first part containing the organic peroxide may be the main part, while the second part containing the reducing agent may be the primer. Alternatively, components (a), (b), and (c) may be contained in a second part containing a reducing agent. That is, the second part containing the reducing agent may be the main part, while the first part containing the organic peroxide may be the curing agent.

[0033] The (meth)acrylic monomer (component (a)) contained in the adhesive composition of the present disclosure may be a monofunctional (meth)acrylate monomer. Examples of the monofunctional (meth)acrylate monomer include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-lauryl (meth)acrylate, and tridecyl (meth)acrylate. Examples of the acrylic monomer include alicyclic (meth)acrylates such as (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, cyclohexyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate, aromatic ring-containing (meth)acrylates such as benzyl (meth)acrylate and phenoxyethyl (meth)acrylate, and heterocyclic ring-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and glycidyl (meth)acrylate. These may be used alone or in combination of two or more. For example, the first and second agents may contain different types of (meth)acrylic monomers, or may contain the same types of (meth)acrylic monomers.

[0034] The adhesive composition of the present disclosure further contains (meth)acrylic acid and / or a hydroxyalkyl (meth)acrylate as component (b). Examples of (meth)acrylic acid include acrylic acid and methacrylic acid. When considering the ease of adjusting the reactivity when mixing the first and second parts, methacrylic acid is preferred. Examples of hydroxylalkyl (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyisobutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, and hydroxylauryl (meth)acrylate. When considering the ease of adjusting the reactivity when mixing the first and second parts, 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate are preferred. The adhesive composition of the present disclosure may contain one or more (meth)acrylic acids and / or hydroxyalkyl (meth)acrylates. For example, the first and second parts may contain different types of (meth)acrylic acids and / or hydroxyalkyl (meth)acrylates, or may be the same type.

[0035] The adhesive composition of the present disclosure further contains a thickener as component (c). The thickener may be a polymer such as a thermoplastic resin or rubber. The inclusion of a thickener can improve the impact strength and peel strength of the adhesive. Specific examples of thickeners contained in the adhesive composition of the present disclosure include thermoplastic resins such as (meth)acrylic acid ester copolymers, methyl methacrylate-butadiene-styrene copolymers (MBS resins), methyl methacrylate-butadiene-acrylonitrile-styrene copolymers (MBAS resins), styrene-butadiene copolymers (SBS resins), and acrylonitrile-butadiene-styrene copolymers (ABS resins), and synthetic rubbers such as styrene-butadiene rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), ethylene-acrylic rubber, and epichlorohydrin rubber. These may be used alone or in combination of two or more. For example, the first and second agents may contain different types of thickeners, or may contain the same type of thickener.

[0036] The content of component (a) may be 1 part by weight or more and 50 parts by weight or less, based on a total of 100 parts by weight of components (a), (b), and (c) contained in the adhesive composition. The content of component (b) may be 1 part by weight or more and 50 parts by weight or less, and more preferably 5 parts by weight or more and 30 parts by weight or less, based on a total of 100 parts by weight of components (a), (b), and (c) contained in the adhesive composition. The content of component (c) may be 1 part by weight or more and 50 parts by weight or less, and more preferably 1 part by weight or more and 30 parts by weight or less, based on a total of 100 parts by weight of components (a), (b), and (c) contained in the adhesive composition. In this specification, the term "content in the adhesive composition" refers to the total amount of the same component contained in the first and second parts. When the same component is contained in both the first and second parts, the contents of the same component in the first and second parts may be the same or different.

[0037] The first agent of the adhesive composition of the present disclosure contains an organic peroxide. Examples of organic peroxides include hydroperoxides such as t-butyl hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, and diisopropylbenzene hydroperoxide, and diacyl peroxides such as t-butyl peroxybenzoate, t-butyl peroxydecanoates, dibenzoyl peroxide, and diisobutyl peroxide. Among these, hydroperoxides are preferred from the viewpoint of reactivity. These may be used alone or in combination of two or more.

[0038] The content of the organic peroxide contained in the first agent may be 0.1 to 10 parts by weight, and more preferably 1 to 10 parts by weight, per 100 parts by weight of the total of components (a), (b), and (c) contained in the first agent. When the content of the organic peroxide is within the above range, polymerization can be carried out at a suitable reaction rate, and the first agent can be stably stored before being mixed with the second agent.

[0039] The second part of the adhesive composition of the present disclosure contains a reducing agent. The reducing agent forms a redox catalyst system with the organic peroxide contained in the first part. Examples of such reducing agents include thiourea compounds such as ethylene thiourea, trimethylthiourea, tetramethylthiourea, benzoylthiourea, and acetylthiourea; metal soaps such as vanadyl octenate, vanadyl naphthenate, and vanadyl stearate; vanadyl acetylacetonate, vanadium acetylacetonate, vanadium pentoxide, and vanadyl stearate; cobalt compounds such as cobalt octylate, cobalt naphthenate, and cobalt acetylacetonate; and aromatic tertiary amines such as N,N-dimethylaniline, N,N-dimethyl-p-toluidine, and p-tolyldiethanolamine. Among these, thiourea compounds and vanadium compounds are preferred in terms of reactivity. These may be used alone or in combination.

[0040] When the adhesive composition is a two-part main component, the content of the reducing agent in the second component may be 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total of components (a), (b), and (c) contained in the second component. When the content of the reducing agent is within the above range, polymerization can be carried out at a suitable reaction rate, and the second component can be stably stored before being mixed with the first component.

[0041] When the adhesive composition is of the main agent-primer type, the content of the reducing agent contained in the second agent as a primer may be 0.1 parts by weight or more and 10 parts by weight or less, and more preferably 0.5 parts by weight or more and 5 parts by weight or less, per 100 parts by weight of the total of components (a), (b), and (c) contained in the first agent as the main agent.

[0042] When the adhesive composition is of the main agent-curing agent type, the content of the organic peroxide contained in the first agent as the curing agent may be 0.1 parts by weight or more and 10 parts by weight or less, and more preferably 0.5 parts by weight or more and 5 parts by weight or less, per 100 parts by weight of the total of components (a), (b), and (c) contained in the second agent as the main agent.

[0043] When the adhesive composition is a base component-primer type or a base component-curing agent type, the primer or curing agent of the first and second components may further contain a solvent. The solvent may be an organic solvent capable of dissolving the organic peroxide or reducing agent contained in the primer or curing agent, and is preferably a volatile organic solvent. Examples of solvents include toluene, xylene, ethyl acetate, ethyl propionate, acetone, methyl ethyl ketone, methyl butyl ketone, methanol, ethanol, isopropyl alcohol, and methylcyclohexane. These may be used alone or in combination of two or more.

[0044] The adhesive composition of the present disclosure may further include a phosphate ester compound in at least one of the first and second parts. The inclusion of a phosphate ester compound can improve the adhesive strength of the adhesive composition. Specifically, the phosphate ester compound can promote curing when the first and second parts are mixed or contacted to initiate a polymerization reaction, and can improve adhesion to the adherend.

[0045] Furthermore, the adhesive composition of the present disclosure may contain additional components added to the first and / or second parts as needed, such as various known additives, such as a silane coupling agent, a polymerization inhibitor, an antioxidant, paraffin, a plasticizer, a filler, a pigment, and / or a colorant.

[0046] The above describes embodiments of the present disclosure, but the present disclosure is not limited to these, and various modifications based on the knowledge of those skilled in the art are possible, such as combining the above configurations, as long as they do not deviate from the spirit of the claims. [Example]

[0047] The present disclosure will be described in more detail below with reference to examples, in which all parts indicating the amount of each component used are parts by weight.

[0048] <Composition of the first and second agents> (a) Monofunctional (meth)acrylate monomer Methyl methacrylate (MMA, manufactured by Mitsubishi Gas Chemical Company, Inc.) (b) (Meth)acrylic acid / hydroxyalkyl (meth)acrylate 2-Hydroxyethyl methacrylate (2-HEMA, manufactured by Mitsubishi Chemical Corporation) Methacrylic acid (MAa, manufactured by Mitsubishi Chemical Corporation) (c) Thickener Methacrylic resin (Delpet LP-1 (hereinafter also referred to as LP-1), manufactured by Asahi Kasei Chemicals Corporation) Nitrile rubber (NBR) (Niopl DN219 (hereinafter also referred to as DN219), manufactured by Zeon Corporation) (d) Reactive flame retardants Dimethyl vinyl phosphonate (VHP-1, manufactured by Koatsu Gas Kogyo Co., Ltd.) Diethyl vinylphosphonate (VHP-2, manufactured by Koatsu Gas Kogyo Co., Ltd.) Diphenylvinylphosphonate (VHP-3, manufactured by Koatsu Gas Kogyo Co., Ltd.) (d') Additive-type flame retardant (comparison example) Organophosphorus compounds (Fireguard FCX-210 (hereinafter also referred to as FCX-210), manufactured by Teijin Limited) Aromatic condensed phosphate ester (PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.) Aromatic phosphate amidate (DAIGUARD-850 (hereinafter also referred to as Daiguard), manufactured by Daihachi Chemical Industry Co., Ltd.) (e) Organic peroxide Cumene hydroperoxide (CHP, manufactured by NOF Corporation) (f) reducing agent 1-benzoyl-2-thiourea (BTU, manufactured by Sanuki Chemical Industry Co., Ltd.) Vanadyl acetylacetonate (hereinafter referred to as VO(AA)2) (manufactured by Shinko Chemical Industry Co., Ltd.) (g) Polymerization inhibitor Furthermore, hydroquinone (HQ) was used as the first agent as a polymerization inhibitor.

[0049] <Phosphorus content> The phosphorus content (wt%) relative to the total amount after addition was theoretically calculated from the phosphorus content of each flame retardant.

[0050] In the following examples and comparative examples, flame retardancy and adhesive tests were carried out under the following conditions.

[0051] <Flame retardancy test> Flame retardancy tests were conducted in accordance with UL94HB. Test pieces measuring 125 mm x 13 mm x 3 mm were prepared from the cured product obtained by mixing the first and second parts of each adhesive composition in the Examples and Comparative Examples. Those that met the UL94HB test criteria were evaluated as ◯, and those that did not were evaluated as ×.

[0052] <Tensile shear strength> To evaluate adhesive strength, tensile shear strength was measured. SPHC sandblasted steel plates measuring 100 mm × 20 mm × 2.3 mm were used as the metal plates to be bonded with the adhesive composition. The metal plates were bonded together using each of the adhesive compositions of the Examples and Comparative Examples, and 24 hours after bonding, the tensile shear strength was measured at a tensile speed of 25 mm / min using a testing machine (Shimadzu Corporation, AG-50kNX). The measurement temperature was 23°C. The overlap area of ​​the bonding surfaces was 10 mm × 20 mm.

[0053] <Storage stability test> As a storage stability test for the adhesive composition, the adhesive composition was left at an ambient temperature of 40°C for 10 days, and the state of the adhesive composition after leaving it was checked. When no changes such as separation of components and / or increase in viscosity (thickening) were observed compared to before leaving it, it was evaluated as good.

[0054] <Result> The compositions of the first and second parts and the evaluation results of various tests for each of the adhesive compositions of the Examples and Comparative Examples are shown in Table 1. The content of each component shown in the table is the number of parts blended in each of the first and second parts.

[0055] [Table 1]

[0056] As shown in Table 1, in the adhesive compositions of Comparative Examples 2, 3, 5, and 7, which contained an additive flame retardant, when the additive flame retardant was added until a flame retardancy satisfying the UL94HB pass standard was achieved, the tensile shear strength decreased and sufficient adhesive strength was not obtained. On the other hand, in the adhesive composition of the present disclosure, which uses a reactive flame retardant, the flame retardancy of the cured product obtained from the adhesive composition was improved without an excessive decrease in tensile shear strength, compared to the adhesive composition of Comparative Example 1, which did not contain a flame retardant.

[0057] Furthermore, in the storage stability test, the adhesive compositions of Comparative Examples 2 to 8, which used an additive flame retardant, showed separation and thickening in the adhesive compositions due to poor compatibility between the additive flame retardant and the acrylic resin, and the adhesive compositions had poor stability. On the other hand, the adhesive compositions of Examples 1 to 16, which used a reactive flame retardant, showed no separation or thickening in the adhesive compositions in the storage stability test, and exhibited good storage stability.

[0058] As is clear from the above results, the adhesive composition of the present disclosure exhibits a flame-retardant effect in the resulting cured product, while the adhesive composition performance, such as adhesive strength and storage stability, is not excessively reduced compared to an adhesive composition that does not contain a flame retardant (Comparative Example 1). Therefore, it was found that the present disclosure provides an adhesive composition that has suitable performance as an adhesive composition and is capable of forming a flame-retardant cured adhesive product.

[0059] Furthermore, the adhesive compositions of Examples 2-5, 7-10, and 12 and Comparative Examples 4, 6, and 8 all had a phosphorus content of 1.5%. The cured products formed from the adhesive compositions of the Examples using a reactive flame retardant obtained flame retardancy test results indicating flame retardancy, while the cured products formed from the adhesive compositions of the Comparative Examples using an additive flame retardant did not exhibit sufficient flame retardancy. This indicates that when a flame retardant is used to achieve the same phosphorus content, the cured products formed from the adhesive compositions of the present disclosure using a reactive flame retardant exhibit a higher flame retardancy effect. In other words, according to the present disclosure, an adhesive composition capable of forming a cured product with a suitable flame retardancy effect can be obtained by including a small amount of flame retardant.

[0060] The adhesive composition of the present disclosure includes the following preferred embodiments. <1> The composition includes a first agent containing an organic peroxide and a second agent containing a reducing agent, (a) monofunctional (meth)acrylic monomers; (b) (meth)acrylic acid and / or hydroxyalkyl (meth)acrylate; and (c) Thickener each of which is contained in at least one of the first agent and the second agent, An adhesive composition, wherein at least one of the first agent and the second agent further contains a reactive flame retardant. <2> the content of the component (a) is 30 to 80 parts by weight, the content of the component (b) is 1 to 50 parts by weight, and the content of the component (c) is 1 to 50 parts by weight, out of a total of 100 parts by weight of the component (a), the component (b), and the component (c) contained in the first agent and the second agent; <1> The adhesive composition according to claim 1. <3> The reactive flame retardant is a phosphorus-based reactive flame retardant. <1> or <2> The adhesive composition according to claim 1. <4> The reactive flame retardant is a reactive flame retardant containing a polymerizable unsaturated group. <1> ~ <3> The adhesive composition according to any one of the preceding claims. <5> The reactive flame retardant is represented by the following general formula (I): [ka] (In the formula, R1 is a polymerizable unsaturated group, and R2 and R3 each independently represent an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, or an aryl group having 6 to 14 carbon atoms.) is a phosphorus-based reactive flame retardant represented by <1> ~ <4> The adhesive composition according to any one of the preceding claims. <6> the polymerizable unsaturated group is a vinyl group or a (meth)acryloyl group; <4> or <5> The adhesive composition according to claim 1. <7> the total content of the reactive flame retardant contained in the first agent and the second agent is 7 to 50 parts by weight relative to 100 parts by weight of the total of the component (a), the component (b), and the component (c) contained in the first agent and the second agent; <1> ~ <6> The adhesive composition according to any one of the preceding claims. <8> each of the first agent and the second agent contains the component (a), the component (b), and the component (c); At least one of the first agent and the second agent contains the reactive flame retardant. <1> ~ <7> The adhesive composition according to any one of the preceding claims. <9> Each of the first agent and the second agent contains the reactive flame retardant. <8> The adhesive composition according to claim 1. <10> one of the first agent and the second agent contains the component (a), the component (b), the component (c), and the reactive flame retardant; the other of the first agent and the second agent contains a solvent, and the organic peroxide or the reducing agent is dissolved or dispersed in the solvent; <1> ~ <7> The adhesive composition according to any one of the preceding claims. <11> The first agent and the second agent do not contain an additive-type flame retardant. <1> ~ <10> The adhesive composition according to any one of the preceding claims. <12> <1> ~ <11> A cured product of the adhesive composition according to any one of the preceding claims. [Industrial Applicability]

[0061] The adhesive composition of the present disclosure can be used as an adhesive in various fields that require bonding of objects together, such as electrical, mechanical, and construction fields.

Claims

1. The composition includes a first agent containing an organic peroxide and a second agent containing a reducing agent, (a) a monofunctional (meth)acrylic monomer; (b) (meth)acrylic acid and / or hydroxyalkyl (meth)acrylate; and (c) thickener each of which is contained in at least one of the first agent and the second agent, At least one of the first agent and the second agent further contains a reactive flame retardant, The reactive flame retardant is represented by the following general formula (I): 【Chemistry 1】 (In the formula, R 1 represents a polymerizable unsaturated group, and R 2 and R 3 each independently represent an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, or an aryl group having 6 to 14 carbon atoms.) is a phosphorus-based reactive flame retardant represented by The adhesive composition, wherein the polymerizable unsaturated group is at least one selected from the group consisting of a vinyl group, a (meth)acrylic group, and a (meth)acryloyl group.

2. 2. The adhesive composition according to claim 1, wherein, relative to a total of 100 parts by weight of the component (a), the component (b), and the component (c) contained in the first agent and the second agent, the content of the component (a) is 30 to 80 parts by weight, the content of the component (b) is 1 to 50 parts by weight, and the content of the component (c) is 1 to 50 parts by weight.

3. The adhesive composition according to claim 1 , wherein the polymerizable unsaturated group is a vinyl group or a (meth)acryloyl group.

4. 2. The adhesive composition according to claim 1, wherein the total content of the reactive flame retardant contained in the first agent and the second agent is 7 to 50 parts by weight relative to a total of 100 parts by weight of the component (a), the component (b), and the component (c) contained in the first agent and the second agent.

5. each of the first agent and the second agent contains the component (a), the component (b), and the component (c); The adhesive composition according to claim 1 , wherein at least one of the first part and the second part contains the reactive flame retardant.

6. The adhesive composition according to claim 1 , wherein each of the first part and the second part contains the reactive flame retardant.

7. one of the first agent and the second agent contains the component (a), the component (b), the component (c), and the reactive flame retardant; The adhesive composition according to claim 1 , wherein the other of the first part and the second part contains a solvent, and the organic peroxide or the reducing agent is dissolved or dispersed in the solvent.

8. The adhesive composition according to claim 1 , wherein the first and second parts do not contain an additive-type flame retardant.

9. A cured product of the adhesive composition according to any one of claims 1 to 8.

Images