JPH05125331A - Two-pack acrylic adhesive - Google Patents

Abstract

PURPOSE:To provide the title adhesive excellent in settability and bond strength, useful for e.g. woodworking, made up of A-agent comprising a polymerizable (meth)acrylic monomer, organic peroxide and specific phosphorus compound and B-agent containing a soluble vanadium compound. CONSTITUTION:The objective adhesive made up of (A) A-agent comprising (1) a polymerizable (meth)acrylic monomer such as (meth)acrylic acid, (2) an organic peroxide such as cumene hydroperoxide and (3) pref. 0.5-7wt.% of phosphorous acid and/or at least one kind of acidic phosphorus compounds selected from those of formulas I-III (R1 is aryl, 1-5C alkyl, etc.; R2 is H or R1; R5 and R7 are each aryl; R6 and R8 are each OH or aryl) and (B) B-agent containing pref. 0.1-0.5wt.% of a soluble vanadium compound (e.g. vanadyl acetylacetonate) capable of forming a redox catalytic system with the organic peroxide in the A-agent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has good adhesiveness to poorly-adhesive materials, and is capable of curing the surface of a portion overflowing from a joint and in contact with air. The present invention relates to a liquid-based acrylic adhesive.

[Conventional technology]

 (Meth) acrylic monomer [(meth) acrylic in the present invention represents acrylic or methacrylic. ], A two-component acrylic adhesive containing an organic peroxide and a reducing agent that forms a redox catalyst system with the organic peroxide does not need to be bonded at room temperature in a short time, and complete two-component mixing is unnecessary. It is characterized by good workability. In recent years, the adhesive strength characteristics such as tensile strength, impact strength, peel strength, etc. have also been greatly improved. While the early types are called first-generation acrylic adhesives (FGA), the strength characteristics have been improved recently. We distinguish them by calling them second-generation acrylic adhesives (SGA). According to the difference in composition and workability, there are two-component base agent type and primer type (also referred to as main agent-primer type) (Haraga et al., Japan Adhesion Society Journal vol 24 No.12 1980). Both agent A and agent B contain a (meth) acrylic monomer as a main component, and each has the property of producing a cured product by redox polymerization. In the primer type, one of the two liquids is a curing accelerator solution called a primer, which plays the role of curing the main agent mainly composed of (meth) acrylic monomer by redox polymerization, and does not cure itself. In terms of workability, the two-component base agent type mixes the two liquids just before use, or coats one of the adherends with A agent and the other with B agent and sticks them so that they rub against each other. A method of matching is taken. On the other hand, in the primer type, one primer is applied as thinly as possible on one adherend, the main agent is applied on the other, and then both are rubbed together. Examples of the two-component base agent type are disclosed in JP-A-53-2543 and the like, and examples of the primer type are disclosed in JP-A-51-7040 and JP-B-53-24103. TECHNICAL FIELD The present invention relates to an improvement in a two-component base agent type acrylic adhesive.

[Problems to be Solved by the Invention]

 As mentioned above, two-component acrylic adhesives are widely used in industrial fields such as electricity, machinery, and construction because of their excellent workability and excellent adhesive strength. However, an adhesive of this type, which contains a (meth) acrylic monomer as a main component and cures by radical polymerization, inherently has peculiar drawbacks as described below. That is, (1) air (oxygen) interferes with the polymerization reaction of the (meth) acrylic monomer, so the surface of the part that overflows from the joint and is in contact with air should not be dried due to unpolymerized monomer. ) Materials such as plastics and porous materials that have strong air permeability and woods that contain components that suppress radical polymerization do not cure and the adhesion is poor.

As a method of improving (1), a method of adding paraffin to at least one of the two liquids (Japanese Patent Laid-Open No. 53-2543), and an organic solvent solution in which a substance having an air barrier property is dissolved in a portion protruding from the joint However, the former has the drawback that the adhesive strength deteriorates due to the paraffin deposited on the adhesive interface, while the latter is essentially a three-component type. There is a drawback that workability deteriorates.

 In addition, methods of irradiating with ultraviolet rays and methods of curing with heat have been reported, but they are restricted by the equipment. Further, none of the methods has solved the deficiency of the above (2).

[Means for Solving the Problems]

 The inventors of the present invention have conducted various studies on a method for solving the above-mentioned problems with a two-pack type main component type acrylic adhesive, and as a result, the agent A has an organic peroxide and phosphorous acid or / and a specific structure. The system containing the acidic phosphorus compound and the agent B containing the soluble vanadium compound as the reducing agent is completely cured to the air contact surface at room temperature by the contact or mixing of the two liquids, and the plastic, The present invention has been completed by finding that excellent adhesion is exhibited without inhibiting curing even for difficult-to-adhere materials such as wood.

That is, the present invention forms a redox catalyst system with an agent A mainly composed of a polymerizable (meth) acrylic monomer and an organic peroxide, and an organic peroxide in the polymerizable (meth) acrylic monomer and the agent A. A two-component, main-agent type acrylic adhesive containing a reducing agent as a main component, and a phosphorous acid in the agent A or / and the following general formulas (I), (II) and (III) Wherein, _{R 1} represents an aryl group, aralkyl kill group of 1 to 5 carbon atoms, a halogenated alkyl group, or _{R 3 OR 4 - (R 3} , R 4 are the same or different and may have an alkyl of 1 to 5 carbon atoms And R ₂ is hydrogen or R ₁ ]. [In the formula, R ₅ is an aryl group, and R ₆ is a hydroxyl group or an aryl group] [Wherein, R ₇ is an aryl group, R ₈ is a hydroxyl group or an aryl group], and one or more acidic phosphorus compounds selected from the group B are contained, and the reducing agent in the agent B is soluble vanadium. The present invention relates to a two-component base type acrylic adhesive, which is a compound.

 There are many reports such as Japanese Examined Patent Publication No. 49-21093 regarding an adhesive that uses a redox system composed of an organic peroxide and a soluble vanadium compound. Furthermore, the redox system consisting of organic peroxides, vanadium compounds and acid phosphates is a curing agent system for unsaturated polyester resins (LHALLAN, Plastics, June p250-25 3,1960) and JP-A-48-21775. It is well known in the issue. Further, examples of using an acidic phosphoric acid ester having a specific structure in an acrylic adhesive include JP-A-51-132234 and JP-A-58-147477. The curing agent system of AL LAN, which is used for room temperature curing of unsaturated polyester resin, coexists with a vanadium compound and an acidic phosphoric acid ester, and then an organic peroxide is added to cure it. On the other hand, the present invention relates to a two-component base agent type acrylic adhesive, wherein in the agent A, an organic peroxide and phosphorous acid or / and one of the general formulas (I), (II) and (III) A major feature is that one or more acidic phosphorus compounds coexist and the soluble vanadium compound is contained in the agent B. As a result, the storage stability of each of agents A and B, which are indispensable elements for the two-component, main-agent type acrylic adhesive, is ensured, and the excellent adhesiveness and the protruding portion to difficult-to-adhesive materials not suggested by ALLAN. The surface curability of was obtained. In a two-part curable composition, the one containing an organic peroxide is generally called the main agent and the one containing a reducing agent is also called an accelerator. Phosphorous acid and acidic phosphorus compounds are also a kind of reducing agent. Therefore, it is usually compounded on the accelerator side except for compounding before use. However, if the agent B, that is, the reducing agent side also contains a polymerizable (meth) acrylic monomer, as in the case of the two-component base type acrylic adhesive, the agent B alone starts the polymerization during storage. The vanadium compound coexists with the phosphorous acid or acidic phosphorus compound used in the present invention, and this tendency is remarkable.

 Further, the acidic phosphoric acid ester used for the acrylic adhesive in JP-A-51-132234 and JP-A-58-147477 is an acidic phosphor of the present invention, as will be apparent from the claims or Examples. It is a specific polymerizable acidic phosphoric acid ester different from phosphorus compounds, and its purpose is to improve adhesion to metals and inorganic materials. Even if such a polymerizable acidic phosphoric acid ester is used in the present invention, the above-mentioned object of the present invention cannot be achieved.

 As the polymerizable (meth) acrylic monomer used in the present invention, (meth) acrylic acid, (meth) acrylic acid alkyl ester, phenoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (Meth) acrylic acid hydroxyalkyl ester, poly (meth) acrylate of polyhydric alcohol, epoxy (meth) acrylate obtained by addition reaction of (meth) acrylic acid with epoxy resin, urethane poly (meth) acrylate, polyester Examples thereof include (meth) acrylate, di (meth) acrylate of alkylene oxide adduct of bisphenol A or bisphenol S, and the like.

 In general, in a two-component acrylic adhesive, when the lower alkyl ester of (meth) acrylic acid is the main component, the effect of inhibiting polymerization by oxygen is relatively small, and long-term curing at room temperature is possible without any special method. If left alone for a while, the surface of the protruding part may harden, but when a high-boiling point (meth) acrylic monomer is the main component, the contact surface with air does not harden indefinitely, and air barrier properties such as paraffin Adding materials has no effect. One of the drawbacks of two-component acrylic adhesives on the market is the problem of malodor. This is because a low boiling point lower alkyl ester of (meth) acrylic acid is used to impart surface curability. The reason is that it must be used.

According to the present invention, even if a hydroxyalkyl (meth) acrylate having a high anaerobic polymerization property or other high boiling point monomer is used as a main component, it can be cured to the air contact surface in a short time. There is also a great advantage that it is easy to prepare the above two-component acrylic adhesive.

 Examples of the organic peroxide contained in the agent A include hydroperoxides such as t-butyl hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, and t-butylperoxide. Peroxyesters such as oxylaurate, t-butyl peroxybenzoate, t-butyl peroxide decanoate and the like are suitable, and hydroperoxide is particularly preferable.

 The content of the phosphorous acid and the acidic phosphorus compound of the general formula (I), (II) or (III) in the agent A is 0.01 to 10% by weight, preferably 0.5 to 7% by weight. Examples of acidic phosphorus compounds are monomethyl phosphate, dimethyl phosphate, monoethyl phosphate, diethyl phosphate, monoisopropyl phosphate, diisopropyl phosphate, monobutyl phosphate, dibutyl phosphate, mono-β-chloroethyl phosphate, di-β. -Chlorothier phosphate, mono-β-bromoethyl phosphate, di-β-bromoethyl phosphate, monoethoxyethyl phosphate, diethoxyethyl phosphate, monobutoxyethyl phosphate, dibutoxyethyl phosphate , Phenyl phosphate, diphenyl phosphate, phenyl phosphonic acid, diphenyl phosphonic acid, phenyl phosphonic acid, diphenyl phosphonate O like phosphate and the like, alone or in combination of two or more of these can be used.

 The content of the soluble vanadium compound contained in the agent B is 0.01 to 10% by weight, preferably 0.1 to 0.5% by weight, as the content in the agent B. As an example, vanadyl acetylacetonate, Examples thereof include vanadyl stearate, vanadium naphthenate, vanadium acetyl acetonate, vanadium benzoyl acetonate and vanadyl oxalate.

 In addition, in the present invention, the following compounds may be added for the purpose of improving the performance of the adhesive.

 Polymethylmethacrylate, polyvinyl butyral, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), for the purpose of adjusting the viscosity and improving the flexibility of the cured product. Thermoplastic resins such as methacrylic acid ester-butadiene-styrene copolymer (MBS resin), methacrylic acid ester-butadiene-acrylonitrile-styrene copolymer (MBAS resin), styrene-butadiene rubber (SBR), polybutadiene rubber ( BR), polyisoprene rubber (IR), chloroprene rubber (CR), nitrile rubber (NBR), rubber such as chlorinated rubber, acrylic rubber, epichlorohydrin gum, liquid polybutadiene, terminal acrylic modified liquid polybutadiene, liquid acrylonitrile Liquid rubber such as butadiene copolymer, fine powder polyethylene for imparting thixotropy, dibenzylidene-D-sorbitol, cellulose triacetate, stearic acid amide, bentonite, fine powder silicic acid, etc. As an imparting agent, 2,6-di-t-butyl-4-methylphenol, 2,2-methylenebis (4-methyl-6-t-butylphenol), which enhances long-term storage stability at room temperature, Radical polymerization inhibitors such as benzoquinone, hydroquinone, ethylenediaminetetraacetic acid tetrasodium, oxalic acid, N-methyl-N-nitrosoaniline, N-nitrosodiphenylamine, and ethylenethiourea, acetylthiourea for increasing the adhesion rate. It is a curing accelerator such as benzoylthiourea, and a dye or pigment for coloring. .

〔Example〕

 Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the examples, all parts are parts by weight, and the physical properties were measured as follows.

○ Measurement of adhesive strength In a room at 23 ° C and 50% RH, apply agent A and agent B to one of the adherends thinly, and then rub them together and attach them with a clip. It was fixed so that it did not move and after 24 hours the tensile shear strength was measured according to ASTM D1002-64. The adherend used was 1.6 mm thick cold-rolled steel plate, which was a good adhesive material, and 2.5 mm thick lauan plywood and 2 mm thick polystyrene board, which were representative of difficult-to-bond materials. ..

○ Surface hardenability of the protruding portion The time until the protruding portion, which was adhered using the polystyrene plate as described above, was dry to the touch was measured.

○ Storage stability 50 g of each of agent A and agent B was placed in a 50 cc polyethylene container, and left standing at 50 ° C open to measure the period until gel formation inside.

Examples 1 to 9 Table 1 shows the results obtained by preparing the agent A (No. I) having the following composition and measuring the adhesive strength during the dry time to the touch. The storage stabilizers for both the agents A and B were at 50 ° C. for 10 days or longer. The addition amount of the phosphorus compound in the agent A (No. I) was 0.025 equivalent in terms of the concentration of P-OH groups. Composition of Agent A (No.I) Composition of agent B (No.I) Comparative Examples 1 to 9 Table 2 shows the results of measuring the physical properties in the same manner as in Examples 1 to 9 by changing the phosphorus compound in the agent A (No. I) to the additives shown in Table 2. The addition amount of the phosphorus compounds of Comparative Examples 1 to 6 was 0.025 equivalent in terms of the concentration of P-OH groups.

As is clear from Table 2, when a high molecular weight acidic phosphoric acid ester is used and when an inorganic phosphoric acid other than phosphorous acid is used, either the surface drying property or the adhesive property or both Insufficient, and in Comparative Examples 7 to 9, both surface dryness and adhesiveness are very poor.

Comparative Examples 10 to 14 Example 1 A system in which the components of the present invention are removed from the adhesive agent A (No. I) and agent B (No. I) in Examples 1 to 9 or a system using other components Example 1 Table 3 shows the results of measuring the physical properties prepared in the same manner as in No. 9 to No. 9. The storage stability of agents A and B was 10 days or more at 50 ° C. As is clear from Table 3, if even one component is missing from the composition of the present invention, the desired performance cannot be obtained.

Comparative Examples 15 to 16 Preparation of a B agent (No. II) in which a phosphorus compound coexists with vanadyl acetylacetonate in the B agent, and the compound in the combination with the A agent (No. II) excluding the phosphorus compound was measured. The results obtained are shown in Table 4. As is clear from Table 4, the adhesiveness is sufficient, but the storage stability of the B agent is poor and it is not suitable as a two-component acrylic adhesive.

Composition of Agent A (No. II) Composition of agent B (No. II) Examples 10 to 13 and Comparative Example 17 A two-component acrylic adhesive consisting of agent A (No. III) and agent B (No. III) having the following compositions was prepared, and the physical properties were the same as in Examples 1 to 9. Table 5 shows the measurement results.

The addition amount of the phosphorus compound in the agent A (No. III) is 0.038 equivalent in terms of the concentration of P-OH groups. The storage stability is 50 for both A agent (No. III) and B agent (No. III).
It was 10 days or more at ℃.

Composition of agent A (No. III) Composition of agent B (No. III) Examples 14 to 17 Two-component acrylic adhesives composed of agent A (No. IV) and agent B (No. IV) having the following compositions were prepared, and physical properties were measured in the same manner as in Examples 1 to 13. Is shown in Table 6.

The addition amount of the phosphorus compound in the agent A (No. IV) is 0.025 equivalent in terms of the concentration of P-OH groups. The storage stability was 50 days or longer for both agents A and B for 10 days or longer. Composition of agent A (No. IV) Composition of agent B (No. IV) [Effects of the Invention] As described above, the two-component main agent type acrylic resin of the present invention is characterized in that the agent A contains an organic peroxide and a specific phosphorus compound, and the agent B contains a soluble vanadium compound. The system adhesive strongly adheres to difficult-to-adhere materials such as plastics and wood, and the part that overflows from the joint and is in contact with air cures to the surface in a short time and dries well. Because of its excellent function, it can be advantageously used in various fields such as wood processing, metal processing, manufacturing composite materials, assembling electric parts, and manufacturing vehicles.

Claims (1)

[Claims] 1. A reducing agent which forms a redox catalyst system with a polymerizable (meth) acrylic monomer and an agent A containing an organic peroxide as a main component and the polymerizable (meth) acrylic monomer and an organic peroxide in the agent A. In a two-component, main-agent type acrylic adhesive consisting mainly of agent B, phosphorous acid in agent A and / or the following general formulas (I), (II) and (III) Wherein, _{R 1} represents an aryl group, aralkyl kill group of 1 to 5 carbon atoms, a halogenated alkyl group, or _{R 3 OR 4 - (R 3} , R 4 are the same or different and may have an alkyl of 1 to 5 carbon atoms And R ₂ is hydrogen or R ₁ ]. [In the formula, R ₅ is an aryl group, and R ₆ is a hydroxyl group or an aryl group] [Wherein, R ₇ is an aryl group, R ₈ is a hydroxyl group or an aryl group], and one or more acidic phosphorus compounds selected from the group B are contained, and the reducing agent in the agent B is soluble vanadium. A two-component base type acrylic adhesive characterized by being a compound.