JP2001342216A - Two-part acrylic curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition improved in the curability on the air contact surface while retaining the advantages inherent in the two-part acrylic curable composition in general and without impairing its preservation stability. SOLUTION: This two-part acrylic curable composition is characterized by being obtained by adding, to A-agent and/or B-agent, a total of 0.01-5 pt(s). wt., based on a total of 100 pts.wt. of a (meth)acrylic monomer in both the A-agent and B-agent, of a paraffin or beeswax with a melting point of 40-70 deg.C; wherein the A-agent essentially comprises 100 pts.wt. of the (meth)acrylic monomer, 1-10 pt(s).wt. of an organic peroxide, 0.01-5 pt(s).wt. of an acidic phosphoric ester and 0.01-10 pt(s).wt. of an α-hydroxycarbonyl compound, and the B-agent essentially comprises 100 pts.wt. of the (meth)acrylic monomer, 0.1-10 pt(s).wt. of vanadium compound and 0.1-20 pt(s).wt. of an acidic phosphoric ester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-part acrylic curable composition, and more particularly, to a method in which tackiness of a surface that comes into contact with air during curing is eliminated in a short time, and each of the two parts is cured. The present invention relates to a two-part acrylic curable composition having good storage stability.

[0002]

2. Description of the Related Art A (meth) acrylic monomer (in the present invention, (meth) acryl means acrylic or methacrylic), an organic peroxide, and a redox catalyst system with the organic peroxide. A two-part acrylic curable composition containing a reducing agent cures in a short time at room temperature, and does not require precise metering and mixing of two parts in a stoichiometric sense, and is easy to handle. Because of this feature, they are widely used in the fields of adhesives, paints, coatings and the like. However, the two-pack type acrylic curable composition adheres to the dust due to incomplete curing of the surface (hereinafter, may be simply referred to as an air contact surface) that protrudes from the bonding portion and contacts the air (hereinafter, may be simply referred to as an air contact surface). Or soiling other parts or the clothes of the worker.

[0003] The cause will be described. In the curing reaction of the two-part acrylic curable composition, the starting point is that the organic peroxide is decomposed by the reducing agent when the two parts come into contact, and radicals are generated. The generated radicals become (meth) acrylic radicals in the curing process and participate in the growth reaction. Here, the polyester resin handbook (Takiyama; published by Nikkan Kogyo Shimbun, published on June 30, 1988, p. 745) states, "In the presence of a large amount of oxygen such as a surface in contact with air, radicals and oxygen The reaction rate is said to be one million times faster than the reaction rate between the radical and the monomer, and most of the generated radicals are combined with oxygen to form peroxide radicals, which have the ability to polymerize further. The polymer chains are terminated because they are decomposed in a short time, and as a result, low molecular weight polymer remains on the surface and appears sticky. " Therefore, it is considered that the cause of the stickiness of the air contact surface of the two-part acrylic curable composition is due to oxygen in the air.

[0004] In order to solve this problem, various methods have been conventionally proposed. For example, there is a method of curing in an inert atmosphere such as nitrogen, or a method of covering the air contact surface with a film, but these methods are not practical. On the other hand, an example using a paraffin and a volatile solvent is disclosed as a practically convenient method. For example, JP-A-50-148432, JP-B-55-1
Japanese Patent No. 7041 is composed of two liquids consisting of a liquid obtained by dissolving or dispersing a specific reducing agent in a volatile solvent and a main agent composed of a (meth) acrylic monomer, peroxide and paraffin, and reducing one side of the material surface. Application with a solution
After the solvent evaporates, the main agent is applied to the other material, and the two materials are bonded and cured. However, this method requires a waiting time for evaporating the solvent, and depending on the type of the solvent, it may cause ignition or poisoning, or may cause problems such as environmental pollution. Japanese Patent Application Laid-Open No. 53-16049 discloses that a base material composed of a (meth) acrylic monomer and an organic peroxide is adhered to a base material composed of a (meth) acrylic monomer and a reducing agent and then protruded from a joint. A method of applying a volatile solvent solution of an air barrier substance such as paraffin to such an adhesive is disclosed. In this method, since three liquids are substantially handled, not only the operation becomes complicated, but also the same problem as described above depending on the type of the solvent.

Further, Japanese Patent Application Laid-Open No. 54-71130 discloses a (meth) acrylic monomer having a boiling point of 200 ° C. or more at normal pressure, which is strongly affected by polymerization inhibition of air or oxygen, an organic peroxide, a reducing agent, Paraffins, and have a solubility for paraffins and a boiling point of 120 at normal pressure.
An adhesive composition comprising a volatile solvent having a temperature of less than or equal to ° C. is disclosed. However, the adhesive composition suffers from poor curing and insufficient adhesive strength if the solvent remains in the cured product without volatilization, and furthermore, if the contacting material is plastic, the plastic will suffer from defects such as deterioration and cracks. May cause.

In order to improve the curability of a surface in contact with air without using a volatile solvent, Japanese Patent Publication No. 55-1957 discloses a method for improving the curability of an alkyl group. A agent comprising alkyl monoester of 1 to 3 (meth) acrylate, organic hydroperoxide, and polymerization inhibitor, (meth) having 1 to 3 carbon atoms of alkyl group
A non-anaerobic two-part adhesive in which a diene rubber is added to at least one of the A agent or the B agent of a composition containing an alkyl acrylate monoester and a B agent comprising a thioamide compound as an essential component, Further, in the detailed description of the invention, there is a description that by blending paraffin wax, the liquid protruding from the bonded portion can be cured. This adhesive also cures the portion of the adhesive that has run out, regardless of the presence or absence of oxygen. However, among the (meth) acrylic monomers, the odor, flammability, and shrinkage during curing are large.
When an alkyl (meth) acrylate monoester having 1 to 3 carbon atoms in the alkyl group is not used, there is a disadvantage that curing of the air contact surface is insufficient even when paraffins are added.

On the other hand, Japanese Patent Publication No. 2-681 discloses an A agent containing a (meth) acrylic monomer and an organic peroxide having a low odor and a boiling point of 150 ° C. or more and having little adverse effect on the environment.
Either a (meth) acrylic monomer having a boiling point of 150 ° C. or more and thiourea as a curing accelerator, and / or a copper salt of a thiourea derivative and an organic acid, and / or a B agent containing a copper-containing chelate compound A curable composition is disclosed in which one or both of them contains paraffins having a melting point of 35 ° C. or more, so that the curing speed of the surface in air is accelerated. However, when the storage stability is further improved by adding a polymerization inhibitor to the agent A described here, even if paraffins are added, the curing of the air contact surface is not improved.

Further, the present inventors have disclosed Japanese Patent Application Laid-Open No. 9-53051.
In the publication, the composition comprises an A agent containing a (meth) acrylic monomer, an organic peroxide, an acid phosphate, and an α-hydroxycarbonyl compound, and a B agent containing a (meth) acrylic monomer, a vanadium compound, and an acid phosphate. The proposed two-component acrylic adhesive has a rapid curing of the air contact surface and good storage stability.
It is still insufficient for some applications, and further improvement has been required.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the above-mentioned problems while maintaining the advantages of a two-part acrylic curable composition and without impairing its storage stability. An object of the present invention is to provide a two-part acrylic curable composition having improved contact surface curability.

[0010]

Means for Solving the Problems The present inventors have used an excellent redox catalyst system and an air-blocking substance in combination,
We thought that the above problems could be solved, and conducted intensive research. As a result, if a reducing agent that significantly accelerates the decomposition of peroxide is used, the radicals generated by the decomposition of the peroxide are partially inhibited by the polymerization inhibitor or dissolved oxygen, and the inhibition by the oxygen on the surface is minimized. As the growth reaction progresses, the air-blocking substance dissolved in the liquid starts to precipitate from inside the liquid, and eventually an air-blocking layer is formed on the surface to eliminate the influence of air. It was found that curing proceeded sufficiently.

Specifically, a combination of a (meth) acrylic monomer, an organic peroxide, a vanadium compound, an acidic phosphate ester, and an α-hydroxycarbonyl compound proposed in JP-A-9-53051 as a redox catalyst system is used. The present inventors have found that the above-mentioned problems can be solved when paraffin having a specific melting point range or beeswax is used as the air-blocking substance, leading to the present invention. That is, the present invention provides 100 parts by weight of a (meth) acrylic monomer, 1 to 10 parts by weight of an organic peroxide, and 0.0
1 to 5 parts by weight, α-hydroxycarbonyl compound 0.0
Agent A containing 1 to 10 parts by weight as an essential component, and (meth)
100 parts by weight of acrylic monomer, 0.1 to 10 parts by weight of vanadium compound, 0.1 to 20 acidic phosphate ester
A component is added to at least one of the agent B having a weight part as an essential component.
Amount of (meth) acrylic monomer in Agent B and Agent B 10
A two-part acrylic curable composition characterized in that a total of 0.01 to 5 parts by weight of paraffin or beeswax having a melting point of 40 to 70 ° C. is blended with respect to 0 parts by weight. It is.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the present invention, the (meth) acrylic monomer used for both the A agent and the B agent includes (meth) acrylic acid, alkyl (meth) acrylate, phenoxyethyl (meth) acrylate, and cyclohexyl (meth).
Acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyalkyl (meth) acrylate, poly (meth) acrylate of polyhydric alcohol, epoxy (meth) acrylate obtained by adding (meth) acrylic acid to epoxy resin, Examples thereof include urethane (meth) acrylate, polyester (meth) acrylate, and di (meth) acrylate of an alkylene oxide adduct of bisphenol A. These may be used alone or in combination of two or more.

The organic peroxide compounded in the agent A includes hydroperoxides such as t-butyl hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, and the like. t-butyl peroxy laurate, t-butyl peroxybenzoate, t
Peroxyesters such as -butyl peroxide decanoate and the like can be used alone or in combination of two or more, but hydroperoxides are particularly preferred. The compounding amount of the organic peroxide is 1 to 10 based on 100 parts by weight of the (meth) acrylic monomer compounded in the agent A.
Part by weight is preferable, and 2 to 5 parts by weight is more preferable. If the amount of the organic peroxide is less than 1 part by weight, the curing rate is decreased, which is not preferable. On the other hand, if it exceeds 10 parts by weight, the storage stability of the adhesive is undesirably deteriorated.

The acidic phosphoric acid ester to be incorporated in the agent A includes monomethyl phosphate, dimethyl phosphate, monoethyl phosphate, diethyl phosphate, monobutyl phosphate, dibutyl phosphate, mono-β-chloroform. Ethyl phosphate, di-β-chloroethyl phosphate, monoethoxyethyl phosphate, diethoxyethyl phosphate, phenyl phosphate, diphenyl phosphate, mono (meth) acryloyloxyethyl phosphate, di (meth) acryloyloxyethyl Phosphate, mono (meth) acryloyloxypropyl phosphate, di (meth) acryloyloxypropyl phosphate, polypropylene glycol mono (meth)
Acrylate phosphate and the like can be mentioned, and these can be used alone or in combination of two or more. From the viewpoint of storage stability, the compounding amount of the acidic phosphoric acid ester is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the (meth) acrylic monomer compounded in the agent A.
The amount is more preferably from 0.5 to 2 parts by weight. If the compounding amount of the acidic phosphoric acid ester is less than 0.01 part by weight, the storage stability is unfavorably reduced, and if it exceeds 5 parts by weight, the storage stability is undesirably reduced.

Further, the α-hydroxycarbonyl compound to be incorporated in the agent A includes α-hydroxycarboxylic acids such as lactic acid, tartaric acid, malic acid, glycolic acid and citric acid;
Α- such as methyl lactate, ethyl lactate and ethyl glycolate
Hydroxycarboxylic acid ester, hydroxyacetone,
Α such as dihydroxyacetone, acetoin, benzoin, etc.
-Ketols, addition products of an α-hydroxycarboxylic acid with an epoxy compound or an oxazoline compound, and the like, and these are used alone or in combination of two or more.

The compounding amount of the α-hydroxycarbonyl compound is determined based on the amount of the (meth) acrylic monomer 100
It is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight based on part by weight. If the amount of the α-hydroxycarbonyl compound is less than 0.01 part by weight, the improvement of the curing rate is not remarkable, so that it is not preferable.
Conversely, if the amount exceeds 10 parts by weight, not only the improvement of the curing rate in proportion to the compounding amount will not be observed, but also the storage stability will be reduced, which is not preferable.

On the other hand, examples of the vanadium compound to be blended in the agent B include vanadyl acetylacetonate, vanadyl stearate, vanadium naphthenate, vanadium acetylacetonate, vanadium benzoylacetonate, and the like. These are used in combination of two or more. The compounding amount of the vanadium compound is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable (meth) acrylic monomer compounded in the agent B,
Further, 1 to 5 parts by weight is more preferable. If the compounding amount of the vanadium compound is less than 0.1 part by weight, the curing rate is low, which is not preferable.On the contrary, even if it exceeds 10 parts by weight, the improvement of the curing rate in proportion to the compounding amount is not observed,
It is not preferable because storage stability is reduced.

The acidic phosphoric acid ester blended in the agent B may be the same compound as that blended in the agent A. These compounds may be used alone or in combination of two or more. Can be The amount of the acidic phosphoric acid ester is determined by the amount of the (meth) acrylic monomer 10
0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 0 parts by weight. If the compounding amount of the vanadium compound is less than 0.1 part by weight, the storage stability decreases, which is not preferable. Conversely, if the compounding amount exceeds 20 parts by weight, the improvement of the curing rate in proportion to the compounding amount is not seen, which is not preferable.

The paraffin or beeswax to be added to at least one of the agent A and the agent B has a melting point of 40 to 70 ° C., and these may be used alone or in combination of two or more. . The amount of the paraffin or beeswax is 0.01 to 100 parts by weight of the total of the (meth) acrylic monomer contained in the A agent and the B agent.
It is preferably 5 parts by weight, more preferably 0.05 to 2.5 parts by weight. If the blending amount of paraffin or beeswax is less than 0.01 part by weight, the curing speed of the surface in contact with air is not remarkably improved and it is not preferable, and if it exceeds 5 parts by weight, the curing is proportional to the blending amount. It is not preferable because not only the improvement in the speed is not seen but also the adhesion to the material is reduced.

In addition, in the present invention, polymethyl methacrylate, polyvinyl butyral, acrylonitrile-styrene copolymer is used in the agent A and / or the agent B for the purpose of adjusting the viscosity and improving the flexibility of the cured product. (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), methacrylic acid ester-
Thermoplastic resins such as butadiene-styrene copolymer (MBS resin), methacrylate-butadiene-acrylonitrile-styrene copolymer (MBAS resin), styrene-butadiene rubber (SBR), polybutadiene rubber (BR), and polyisoprene rubber (IR), chloroprene rubber (CR), nitrile rubber (NBR), rubber such as chlorinated rubber, acrylic rubber, epichlorohydrin rubber, liquid polybutadiene, liquid polybutadiene modified with terminal acrylic,
Liquid rubber such as liquid acrylonitrile-butadiene copolymer, fine powdered polyethylene for the purpose of imparting thixotropic properties, dibenzylidene-D-sorbitol, cellulose triacetate, stearamide, bentonite,
Thixotropic agents such as finely divided silica, and 2,6-di-t-butyl-4-to improve long-term storage stability at room temperature.
Methylphenol, 2,2-methylenebis (4-methyl-6-t-butylphenol), benzoquinone, hydroquinone, quinhydrone, ethylenediaminetetraacetic acid tetrasodium, oxalic acid, N-methyl-N-nitrosoaniline, N-nitrosodiphenylamine and the like A radical polymerization inhibitor and a dye or pigment for coloring can be blended.

Further, according to the present invention, A
The viscosity of the agent and the agent B can be set flexibly. That is,
In an application in which the A agent and the B agent are mixed and used during use, the composition may be determined so that the A agent and the B agent have substantially the same viscosity. In addition, for example, one liquid is applied thinly to one adherend, the other liquid is applied to the other adherend, and then the two are adhered together, a so-called primer type. In the application to be used, for example, the composition may be determined so that the A agent has a high viscosity and the B agent has a low viscosity. For adjusting the viscosity, the above-mentioned thermoplastic resin, rubber, liquid rubber, thixotropic agent and the like are suitably used.

The two-part acrylic curable composition of the present invention has a remarkably improved curing speed on the air contact surface. This is because the redox catalyst system consisting of organic peroxide, acidic phosphate, vanadium compound and α-hydroxycarbonyl compound is active and the decomposition rate of organic peroxide is remarkably fast. It is presumed that the performance was added.

On the other hand, from the viewpoint of storage stability of the adhesive, α
-In order to avoid the coexistence of the hydroxycarbonyl compound and the vanadium compound, the two-part form is used;
The storage stability can be ensured by blending the acid phosphate ester as an essential component in the agent and the agent B.

[0024]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In these examples, all parts are by weight. In the following Examples and Comparative Examples, storage stability, set time, dry time to touch, and tensile shear strength were measured under the following conditions. <Storage stability> 80 g of each of the A agent and the B agent are placed in a 100 cc glass bottle, and stored in a drier kept at 40 ° C., and the time until gel formation is measured. <Set time> 1.6 × 2 at 23 ° C. and 50% RH
A cold-rolled steel sheet having a shape of 5 × 100 mm is mixed and adhered in an equal amount of the agent A and the agent B on a 12 mm wrap, and the time until the film is not peeled off even when a load of 5 kgf is applied is measured. <Touch Drying Time> At 23 ° C. and 50% RH, the time required for the sticking of the protruding portion to disappear by finger touch after adhesion is measured in the same manner as the measurement of the set time. <Tensile shear strength> A cold rolled steel plate having a shape of 1.6 × 25 × 100 mm was adhered with a 12 mm wrap, and ASTM D
It measures according to 1002-64.

[Example 1, Comparative Examples 1-2] 3 shown in Table 1
Two kinds of two-part acrylic curable compositions were prepared and their performance was evaluated. The storage stability was all stable for 20 days or more.

[0026]

[Table 1]

From Table 1, it is found that the first embodiment satisfying the requirements of the present invention is shown.
Indicates that the set time and the touch dry time are significantly reduced as compared with Comparative Example 1 in which paraffin is used but malic acid which is an α-hydroxycarbonyl compound is not used. Further, it can be seen that Comparative Example 2 in which malic acid, which is an α-hydroxycarbonyl compound, but no paraffin is used, has a significantly longer dry time to the touch as compared to Example 1. From these facts, it can be seen that the combination of the catalyst system, α-hydroxycarbonyl and paraffin shown in the present invention has a unique effect on set time and dryness to the touch.

Examples 2-3 and Comparative Examples 3-4 Four types of two-part acrylic curable compositions shown in Table 2 were prepared and their performance was evaluated.

[0029]

[Table 2]

From Table 2, Example 2, which satisfies the requirements of the present invention,
3 shows that both the storage stability and the dryness to the touch are good. On the other hand, Comparative Example 3 using a catalyst system different from the catalyst system shown in the present invention is poor in dryness to the touch even though paraffin is used.

Example 4, Comparative Examples 5 to 7 The common composition shown in Table 3 was mixed with 0.2 parts by weight of the air-blocking substances shown in Table 4 in Agent A and Agent B, respectively. A liquid acrylic curable composition was prepared. Then, the performance of the obtained two-part acrylic curable composition was evaluated. Table 4 shows the results. The storage stability was stable for 20 days or more.

[0032]

[Table 3]

[0033]

[Table 4]

Table 4 shows that Example 4 using paraffin having a melting point in the range shown in the present invention has good dryness to the touch. On the other hand, Comparative Example 4 using paraffin having a melting point exceeding the range shown in the present invention, and Comparative Examples 5 and 6 using air barrier substances other than those shown in the present invention.
It is clear that the dryness to the touch is poor.

[0035]

As described above, according to the present invention, the curability of the air contact surface is improved while maintaining the advantages of the two-part acrylic curable composition and without impairing the storage stability. Provided is a cured two-part acrylic curable composition. The two-part acrylic curable composition provided by the present invention completely cures up to the air contact surface, does not cause stickiness on the surface of the cured product, adheres dust, and wears other parts and clothes of workers. Will not pollute. It can be said that the two-part acrylic curable composition of the present invention having such features is useful not only for industrial use but also for general households.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Matsuda ▲ Hide ▼ Akira 1515 Nakatsu-cho, Marugame-shi, Kagawa Prefecture F-term in Okura Industrial Co., Ltd. (reference) 4J011 PA28 PA46 PA56 PB40 PC02 4J015 CA04 4J040 BA172 FA091 FA092 FA131 FA132 FA141 FA142 FA151 FA152 FA161 FA162 FA171 FA172 FA261 FA262 FA271 FA272 FA291 FA292 HB01 HB19 HB22 HB31 HB41 HB44 HD24 HD41 JA13 JB05 LA08 4J100 AJ02P AJ02Q AL03P AL03Q AL08P AL08Q AL09P AL09Q AL63P AL63Q ALPQ BC66 BC03 BC03 CA01 CA04 FA03 FA08 JA03

Claims (1)

[Claims] 1. 100 parts by weight of a (meth) acrylic monomer, 1 to 10 parts by weight of an organic peroxide, 0.01 to 5 parts by weight of an acidic phosphate ester, and 0.01 to 10 parts by weight of an α-hydroxycarbonyl compound. Agent A as an essential component, and
(Meth) acrylic monomer 100 parts by weight, vanadium compound 0.1 to 10 parts by weight, acidic phosphate 0.1
To at least one of the B agent having an essential component of 〜20 parts by weight, a paraffin having a melting point of 40 to 70 ° C. or a bee wax based on 100 parts by weight of the total amount of the (meth) acrylic monomer in the A agent and the B agent. Is a total amount of 0.01 to 5 parts by weight.