Surface treatment agent for cyanoacrylate adhesive composition and bonding method using the surface treatment agent

Abstract

To provide a surface treatment agent for a cyanoacrylate adhesive composition that makes it possible to check the application site and the amount applied after application.SOLUTION: The surface treatment agent contains the following components (A) to (C) in a specific proportion: (A) an organic solvent containing an optionally branched, C5-15 aliphatic hydrocarbon solvent; (B) at least one polyamine compound selected from the group consisting of compounds represented by the general formulas (1) and (2) in the figure; and (C) a compound represented by the general formula (3) in the figure.SELECTED DRAWING: None

Description

【Technical Field】 【0001】 The present invention relates to a surface treatment agent for a cyanoacrylate adhesive composition used for surface treatment of difficult-to-bond materials such as polyolefins such as polypropylene and polyethylene, polyacetal, fluororesin, highly crystalline plastics, and thermoplastic elastomers such as TPE, TPO, and TPV composed of the polyolefin and diene rubber when bonding them using a cyanoacrylate adhesive composition. 【Background Art】 【0002】 A cyanoacrylate adhesive composition mainly composed of a 2-cyanoacrylate monomer generally has extremely high anionic polymerizability and rapidly polymerizes at room temperature with basic substances and nucleophilic substances such as water and alcohol with weak nucleophilicity to give a tough polymer. Utilizing this property, the cyanoacrylate adhesive composition is widely used as an instant adhesive for electrical equipment, transportation equipment, precision equipment, machinery, etc. for bonding various rubbers, plastics, ceramics, etc. in various industrial industries and ordinary households. 【0003】 However, the adhesion of the cyanoacrylate adhesive composition may be extremely poor depending on the material of the adherend. In particular, since the above-mentioned difficult-to-bond materials have low polarity, it is known that it is difficult to adhere them, such as not being able to obtain sufficient adhesion strength or having a slow rising rate of adhesion strength even when using a cyanoacrylate adhesive composition in a normal method. 【0004】 Therefore, various methods for bonding difficult-to-bond materials with a cyanoacrylate adhesive composition have been studied so far. For example, a method of improving the adhesion strength by applying a surface treatment agent (primer) to the surface of the adherend of the difficult-to-bond material in advance and then applying the cyanoacrylate adhesive composition to the surface of the adherend for bonding is known. Also, as the surface treatment agent, for example, a composition containing a diamine compound having a specific structure and an aliphatic hydrocarbon solvent (Patent Document 1) is known. 【Prior Art Documents】 [Patent Documents] 【0005】 [Patent Document 1] Japanese Patent Application Publication No. 9-53052 [Overview of the project] [Problems that the invention aims to solve] 【0006】 However, the above-mentioned surface treatment agent is colorless and transparent, and it needs to be dried after application and before applying the cyanoacrylate adhesive composition, whereas after application, the applied area place Despite the need for confirmation, such confirmation is difficult, and coating leakage occurs, especially when bonding large quantities of adherends. This This sometimes happened. 【0007】 The present invention applies to the coated part after coating. place The objective is to provide a surface treatment agent for cyanoacrylate adhesive compositions that allows for verification. [Means for solving the problem] 【0008】 As a result of diligent research, the inventors have found that the above-mentioned problems can be solved by a surface treatment agent containing the following components (A) to (C) in specific proportions. Specifically, the present invention includes the following invention. 【0009】 [1] A surface treatment agent for cyanoacrylate adhesive compositions, comprising the following (A), (B), and (C), wherein the content of (B) is 0.05 to 5.0 parts by weight per 100 parts by weight of (A), and the content of (C) is 0.02 to 0.55 parts by weight per 100 parts by weight of (A). (A) Organic solvents containing a C5-C15 aliphatic hydrocarbon solvents which may have branching. (B) General formula (1): 【0010】 [ka] (In the above formula (1), R1 to R4 each independently represent a methyl group or an ethyl group, and R5 represents an alkylene group having 1 to 10 carbon atoms which may have a branch.) A compound represented by and the following general formula (2): 【0011】 【Chemical formula】 (In the above formula (2), R6 to R9 each independently represent a methyl group or an ethyl group, and R 10 represents an alkylene group having 1 to 10 carbon atoms which may have a branch, and n represents an integer of 2 to 10.) At least one polyamine compound selected from the group consisting of compounds represented by (C) The following general formula (3): 【0012】 【Chemical formula】 (In the above formula (3), R 11 and R 12 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms which may have a branch.) A compound represented by 【0013】 [2] Among the adherends to be surface-treated, at least one is a polyolefin resin or an elastomer containing a polyolefin resin, the surface treatment agent for a cyanoacrylate adhesive composition according to [1]. 【0014】 [3] An adhesion method for adhering adherends to each other with a cyanoacrylate adhesive composition, the adhesion method including the following steps (1) and (2) in this order as a pre-step of adhesion. (1) A step of applying the surface treatment agent for a cyanoacrylate adhesive composition according to [1] or [2] to at least one of the adherends. (2) A step of drying the applied surface treatment agent for a cyanoacrylate adhesive composition. 【0015】 [4] The adhesion method according to [3], wherein at least one of the adherends is a polyolefin resin or an elastomer containing a polyolefin resin. 【0016】 [5] Furthermore, the adhesion method according to [3], which further includes the following step (a) (however, step (a) is carried out after step (1)). (a) A step of irradiating ultraviolet rays on the coating surface of the surface treatment agent for the cyanoacrylate adhesive composition and confirming the coating surface by fluorescence emission. [Advantages of the Invention] 【0017】 According to the present invention, it is possible to provide a surface treatment agent that can be confirmed after coating. In addition, the surface treatment agent of the present invention is visible in a well-lit indoor environment even after 3 hours from coating, so it is possible to ensure a long working time in subsequent processes and has excellent handleability. Further, the surface treatment agent of the present invention is usually colorless and transparent, and fluorescence emission occurs and it becomes visible by irradiating ultraviolet rays. However, since the fluorescence emission decays to such an extent that it cannot be visually recognized in a well-lit indoor environment after a certain period of time from coating, it does not affect the appearance of the finished product. Also, as shown in the section of Examples described later, according to the surface treatment agent of the present invention, in the adhesion of the above-mentioned difficult-to-adhere materials, a sufficient curing rate can be obtained, and an adhesion strength equal to or higher than that when using the surface treatment agent described in the above Patent Document 1 can be obtained. [Embodiments for Carrying Out the Invention] 【0018】 Hereinafter, the surface treatment agent for the cyanoacrylate adhesive composition of the present invention will be described in detail. 【0019】 [Component (A)] ​​Component (A) contains at least a C5-C15 aliphatic hydrocarbon solvent which may have branching. Specific examples of the C5-C15 aliphatic hydrocarbon solvent which may have branching include pentane, hexane, heptane, octane, nonane, decane, and ligroin. Among these, a C5-C10 aliphatic hydrocarbon solvent which may have branching is preferred, and heptane, octane, nonane, and ligroin are more preferred. These aliphatic hydrocarbon solvents may be used alone or in combination of two or more. 【0020】 In addition, other organic solvents besides the branched aliphatic hydrocarbon solvents having 5 to 15 carbon atoms that may be included in component (A) include, for example, lower alcohol solvents, lower fatty acid ester solvents, ketone solvents, aromatic hydrocarbon solvents, and halogenated hydrocarbon solvents. Specifically, for example, lower alcohol solvents include methanol, ethanol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol; lower fatty acid ester solvents include methyl acetate, ethyl acetate, i-propyl acetate, n-propyl acetate, n-butyl acetate, isobutyl acetate, benzyl acetate, and cyclohexyl acetate; ketone solvents include acetone, methyl ethyl ketone, and methyl isobutyl ketone; aromatic hydrocarbon solvents include benzene, toluene, and xylene; and halogenated hydrocarbon solvents include methylene chloride, 1,1,1-trichloroethane, dichloroethane, trichlorotrifluoroethane, and perchloroethane. These other organic solvents may include one or more types, but it is preferable to use a branched aliphatic hydrocarbon solvent having 5 to 15 carbon atoms alone. 【0021】 [Component (B)] Component (B) is at least one polyamine compound selected from the group consisting of compounds represented by the above general formula (1) and compounds represented by the above general formula (2). 【0022】 In the general formula (1) above, R1 to R4 each independently represent a methyl group or an ethyl group. R5 represents a C1 to C10 alkylene group which may be branched, preferably a linear C1 to C10 alkylene group, and more preferably a linear C1 to C6 alkylene group. It is preferable that R1 to R4 are the same. 【0023】 Specific examples of compounds represented by the general formula (1) include N,N,N',N'-tetramethyldiaminomethane, N,N,N',N'-tetramethyldiaminoethane, N,N,N',N'-tetramethyldiaminopropane, N,N,N',N'-tetramethyldiaminobutane, N,N,N',N'-tetramethyldiaminohexane, N,N,N',N'-tetramethyldiaminoheptane, N,N,N',N'-tetramethyldiaminooctane, N,N,N',N'-tetramethyldiaminodecane, N,N,N',N'-tetraethyldiaminomethane, N,N,N',N'-tetraethyldiaminoethane, N,N,N',N'-tetraethyldiaminopropane, N,N,N',N'-tetraethyldiaminobutane, N,N,N',N'-tetraethyldiaminohexane, and the like. Among these specific examples, N,N,N',N'-tetramethyldiaminoethane, N,N,N',N'-tetramethyldiaminopropane, N,N,N',N'-tetramethyldiaminohexane, and N,N,N',N'-tetraethyldiaminoethane are preferred. 【0024】 In the general formula (2) above, R6 to R9 each independently represent a methyl group or an ethyl group. 10 R represents an alkylene group having 1 to 10 carbon atoms, which may have branching, preferably a linear alkylene group having 1 to 10 carbon atoms, more preferably a linear alkylene group having 1 to 6 carbon atoms, and even more preferably a linear alkylene group having 2 to 3 carbon atoms. n represents an integer from 2 to 10, preferably 2 to 4. It is preferable that R6 to R9 are the same. Also, there are multiple R 10 They may be the same or different, but it is preferable that they be the same. 【0025】 Specific examples of the compound represented by the general formula (2) include N-methyl-N,N-bis[3-(dimethylamino)propyl]amine, N,N,N',N'',N''-pentamethyldiethylenetriamine, and N,N,N',N'',N''-pentamethyl-(3-aminopropyl)ethylenediamine. Among these specific examples, N-methyl-N,N-bis[3-(dimethylamino)propyl]amine and N,N,N',N'',N''-pentamethyldiethylenetriamine are preferred. 【0026】 The content of component (B) is usually 0.05 to 5.0 parts by weight, preferably 0.1 to 5.0 parts by weight, and more preferably 0.3 to 4.0 parts by weight, per 100 parts by weight of component (A). If the amount is less than 0.05 parts by weight, the effect as a surface treatment agent is small and sufficient adhesive strength is not achieved when bonding with the cyanoacrylate adhesive composition. If the amount is more than 5 parts by weight, a layer of component (B) may form on the coated surface, causing the cyanoacrylate adhesive composition to harden immediately after application to the adherend and failing to bond, or the layer of component (B) may peel off, reducing the adhesive strength. 【0027】 [Component (C)] Component (C) is a fluorescent compound represented by the above general formula (3). In the above general formula (3), R 11 and R 12 Each of these independently represents a hydrogen atom or a C1-C8 alkyl group which may have branching, preferably a hydrogen atom or a C1-C4 alkyl group which may have branching. 【0028】 Examples of compounds represented by the above general formula (3) include 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene. 【0029】 The content of component (C) is usually 0.02 to 0.55 parts by weight, preferably 0.05 to 0.30 parts by weight, per 100 parts by weight of component (A). If the content is less than 0.02 parts by weight, sufficient fluorescence emission may not be obtained when checking the application area. If the content is more than 0.55 parts by weight, sufficient adhesive strength may not be obtained when bonding difficult-to-bond materials such as thermoplastic elastomers such as TPE, TPO, and TPV, which are made of polyolefin and diene rubber. 【0030】 The surface treatment agent for cyanoacrylate adhesive compositions of the present invention can be manufactured, for example, by mixing the above-mentioned components (A) to (C). Furthermore, known inorganic compounds, resins, colorants, deodorizers, fragrances, plasticizers, etc., may be added as needed, provided that they do not impair the purpose and effects of the present invention. 【0031】 The cyanoacrylate adhesive composition in the present invention is not particularly limited as long as it contains a conventionally known 2-cyanoacrylate as its main component. Examples of 2-cyanoacrylates included as the main component include esters of 2-cyanoacrylic acid such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, octyl, neopentyl, cyclohexyl, ethylhexyl, dodecyl, allyl, methoxyethyl, ethoxyethyl, methoxypropyl, benzyl, phenyl, chloroethyl, and tetrahydrofurfuryl. These 2-cyanoacrylates may be used alone or in combination of two or more. 【0032】 Furthermore, the cyanoacrylate adhesive composition used in the present invention may, if necessary, contain various fillers, plasticizers, thickeners, strength enhancers, thixotropes, heat resistance imparters, water resistance imparters, rapid curing additives, softeners, flexibility imparters, stabilizers, fragrances, solvents, etc., which are conventionally used in cyanoacrylate adhesive compositions, to the extent that they do not impede the curing speed and stability of the 2-cyanoacrylate monomer. 【0033】 Next, a method for bonding an adherend using a cyanoacrylate adhesive composition (hereinafter sometimes referred to as the bonding method of the present invention) using the surface treatment agent for cyanoacrylate adhesive compositions of the present invention (hereinafter sometimes referred to as the surface treatment agent of the present invention) will be described in detail. 【0034】 The bonding method of the present invention includes the following steps (1) and (2) in this order as a pre-bonding step. (1) A step of applying the surface treatment agent of the present invention to at least one of the objects to be adhered to. (2) A step of drying the applied surface treatment agent of the present invention. 【0035】 In step (1), the adherend may be cleaned in advance by conventional methods. Furthermore, the application method of the surface treatment agent of the present invention can be the same as that of conventionally known surface treatment agents for cyanoacrylate adhesive compositions, for example, dropping from a container or dropper, application with a brush or pen, spraying, or immersing the adherend in the surface treatment agent. Furthermore, the adherend in the present invention is not particularly limited, but by using the surface treatment agent for cyanoacrylate adhesive compositions of the present invention, sufficient curing speed and high adhesive strength can be obtained even when bonding difficult-to-bond materials such as polypropylene, polyethylene and other polyolefins, polyacetal, fluororesins and highly crystalline plastics, and thermoplastic elastomers such as TPE, TPO, and TPV made of polyolefin and diene rubber, which are difficult to bond with cyanoacrylate adhesive compositions alone. Therefore, it is preferable that at least one of the adherends be one of these difficult-to-bond materials. 【0036】 In step (2), a method for drying the surface treatment agent of the present invention includes, for example, a method in which the surface treatment agent of the present invention is applied and then left to stand at room temperature to dry the solvent contained in the surface treatment agent. 【0037】 The bonding method of the present invention may further include the following step (a) as a pre-bonding step. (a) A step of irradiating the coated surface of the cyanoacrylate adhesive composition with ultraviolet light and confirming the coated surface by fluorescence emission (however, step (a) is performed after step (1)). 【0038】 In step (a), the method for irradiating the coated surface with ultraviolet light and confirming the fluorescence emission is not particularly limited, but examples include irradiating the coated surface with ultraviolet light using a known or commercially available ultraviolet irradiation device with an emission wavelength range of less than 400 nm and visually confirming the fluorescence emission. By confirming the coated surface of the surface treatment agent for the cyanoacrylate adhesive composition before applying the cyanoacrylate adhesive composition, the possibility of application omissions can be reduced, and adhesion can be achieved with sufficient curing speed and high adhesive strength. 【0039】 After performing the pre-adhesion steps described above, the adherends can be bonded together, for example, by applying a cyanoacrylate adhesive composition to one or both bonding surfaces of the adherends, joining them together, and then curing them under pressure. [Examples] 【0040】 The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. 【0041】 <Examples 1-11, Comparative Examples 1-10> Surface treatment agents for cyanoacrylate adhesives according to each example and comparative example were prepared by charging each component in the proportions shown in Tables 1 and 2 into a glass container equipped with a stirrer and stirring and dissolving them. Using the obtained surface treatment agents for cyanoacrylate adhesives, each item shown in Tables 1 and 2 was measured and evaluated by the method described below. In Tables 1 and 2, "open time" refers to the drying time from the application of the surface treatment agent for cyanoacrylate adhesives until the cyanoacrylate adhesive composition is dropped. The meanings of the symbols and abbreviations in Tables 1 and 2 are as follows. TPO: Olefin-based thermoplastic elastomer • EPDM: Ethylene Propylene Diene Rubber • PP: Polypropylene • PE: High-density polyethylene (HDPE) 【0042】 <Evaluation of the appearance and uniformity of the surface treatment agent solution> The surface treatment agent for the cyanoacrylate adhesive composition prepared as described above was stored at 25°C for 24 hours, and then the "appearance" and "uniformity of the solution" of the surface treatment agent were visually inspected. 【0043】 <Evaluation of adhesive strength and adhesion status by manual perception> The surface treatment agent for the cyanoacrylate adhesive composition, prepared as described above, was applied to the bonding surface of a TPO board (25 x 50 x 3 mm, manufactured by Engineering Test Services Co., Ltd.) using a cotton swab. After drying the coated surface in a 20°C room for 30 minutes, one drop of the cyanoacrylate adhesive composition (Cyanobond RP-X: manufactured by Taoka Chemical Industry Co., Ltd. (main component: ethyl-α-cyanoacrylate)) was dropped onto an EPDM board (25 x 50 x 2 mm, manufactured by Standard Test Piece Co., Ltd.). The adherends were bonded together with a 1 / 2-inch overlap, then held in place by hand for 2 seconds. Immediately afterward, both adherends were pulled by hand in a 180-degree peeling direction, and the bonding strength and bonding state were evaluated by tactile sensitivity. The evaluation criteria are as follows. 〇: Timber damage ×: Other than material fracture (interfacial fracture, etc.) 【0044】 <Measurement of tensile shear bond strength and evaluation of bond condition> Apply the cyanoacrylate adhesive composition surface treatment agent prepared as described above to the bonding surfaces of both adherends using a cotton swab, and allow to stand in a 20°C room for 15 minutes to dry the coated surfaces. Then, drop two drops of the cyanoacrylate adhesive composition (Cyanobond RP-X: manufactured by Taoka Chemical Industry Co., Ltd. (main component: ethyl-α-cyanoacrylate)) onto the bonding surface of one adherend, bond the adherends together with a 1 / 2 inch overlap, press firmly, and cure for 1 hour. After that, measure the tensile shear bond strength (unit: N / mm²) in accordance with JIS K 6861. 2The adhesion was measured and the bonding state was evaluated. The evaluation criteria are as follows. Polypropylene (PP) and polyethylene (PE) boards (both 25 x 100 x 2 mm, manufactured by Engineering Test Services Co., Ltd.) were prepared as adherends, and PP boards were bonded to each other, and PE boards were bonded to each other. 〇: Timber damage ×: Other than material fracture (interfacial fracture, etc.) 【0045】 <Evaluation of the visibility of the surface treatment agent coated area> The surface treatment agent for the cyanoacrylate adhesive composition prepared as described above was applied to an olefin-based thermoplastic elastomer (TPO) plate (25 × 50 × 3 mm, manufactured by Engineering Test Service Co., Ltd.) using a cotton swab. The applied area was then irradiated with ultraviolet light from a 365 nm handheld ultraviolet light (manufactured by Manaslu Chemical Industries Co., Ltd.) from a distance of 10 cm, and the fluorescence emission of the applied area was visually observed to evaluate its visibility. The fluorescence emission of the applied area was also visually observed in the same manner at predetermined time intervals, and the visibility after the predetermined time intervals was evaluated in the same manner. The evaluation criteria are as follows. ○: The coated area can be inspected in a brightly lit indoor environment with normal lighting. △: The coated area can be inspected in a dark room. ×: Unable to check the applied area. 【0046】 <Effects of surface treatment agents on the appearance of the substrate> The surface treatment agent for the cyanoacrylate adhesive composition prepared as described above was applied to an olefin-based thermoplastic elastomer (TPO) plate (25 x 50 x 3 mm, manufactured by Engineering Test Services Co., Ltd.) using a cotton swab. The effect on the appearance of the adherend was then visually confirmed in a brightly lit indoor environment with normal lighting. 【0047】 [Table 1] 【0048】 [Table 2]

Claims

[Claim 1] A surface treatment agent for cyanoacrylate adhesive compositions, comprising the following (A), (B), and (C), wherein the content of (B) is 0.05 to 5.0 parts by weight per 100 parts by weight of (A), and the content of (C) is 0.02 to 0.55 parts by weight per 100 parts by weight of (A). (A) Organic solvents containing aliphatic hydrocarbon solvents having 5 to 15 carbon atoms, which may be branched. (B) General formula (1) below: 【Chemistry 1】 (In the above formula (1), R １ ~R ４ Each of these independently represents either a methyl group or an ethyl group, R ５ (This represents an alkylene group having 1 to 10 carbon atoms, which may be branched.) Compounds represented by the following general formula (2): 【Chemistry 2】 (In the above formula (2), R ６ ~R ９ Each of these independently represents either a methyl group or an ethyl group, R １０ (where n represents an alkylene group having 1 to 10 carbon atoms, which may be branched, and n represents an integer from 2 to 10.) At least one polyamine compound selected from the group consisting of compounds represented by [formula]. (C) General formula (3) below: 【Transformation 3】 (In the above formula (3), R １１ and R １２ Each of these independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, which may have branches. A compound represented by the formula. [Claim 2] The surface treatment agent for cyanoacrylate adhesive compositions according to claim 1, wherein at least one of the adherends to be surface-treated is a polyolefin resin or an elastomer containing a polyolefin resin. [Claim 3] A bonding method for bonding adherends together using a cyanoacrylate adhesive composition, comprising the following steps (1) and (2) in this order as a pre-bonding step. (1) A step of applying the surface treatment agent for cyanoacrylate adhesive composition according to claim 1 or 2 to at least one of the adherends. (2) A step of drying the applied surface treatment agent for the cyanoacrylate adhesive composition. [Claim 4] The bonding method according to claim 3, wherein at least one of the adherends is a polyolefin resin or an elastomer containing a polyolefin resin. [Claim 5] Furthermore, the bonding method according to claim 3, including the following step (a) (provided that step (a) is performed after step (1)). (a) A step of irradiating the coated surface of a surface treatment agent for cyanoacrylate adhesive composition with ultraviolet light and confirming the coated surface by fluorescence emission.

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