JP2550830B2 - Adhesive composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy adhesive composition having excellent adhesive strength to various substrates, particularly oil surface adhesiveness, water resistance and heat resistance.

[0002]

2. Description of the Related Art Epoxy resin has been widely used as an adhesive because of its excellent adhesiveness with metals and resins, almost no volatile components, small curing shrinkage and good dimensional stability. .

Recently, however, there has been a demand for higher performance, and in particular, there has been a demand for an epoxy adhesive having both peel strength and bending strength, and heat resistance and water resistance. In order to improve the peel strength and bending strength, it is necessary to introduce a flexible component such as an aliphatic epoxy resin into the adhesive or to impart toughness to the epoxy resin by a method such as decreasing the crosslink density. Good, but simply adopting such a method will lower the heat resistance, so a method of adding nitrile rubber or rubber particles was attempted in order to achieve both toughness and heat resistance, but the effect is sufficient. There was a problem that it was not good or the water resistance was lowered.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its purpose is to combine adhesive strength such as peel strength and bending strength with heat resistance and water resistance. An object is to provide an adhesive composition.

[0005]

The composition of the adhesive composition of the present invention which has been able to solve the above-mentioned problems comprises a polymerizable monomer component (A) containing an unsaturated carboxylic acid as an essential component,
Water-soluble or water-dispersible terminal alkyl group-containing polymer [Pa] obtained by polymerization in the presence of an alkyl mercaptan (B) having 6 to 18 carbon atoms
And / or (meth) acrylic acid having a glass transition temperature of 20 ° C. or lower obtained by emulsion polymerization of a (meth) acrylic acid ester monomer (C) using a reactive surfactant composed of a salt thereof and / or a salt thereof as an emulsifier. The gist is that it contains a modified epoxy resin containing an ester polymer particle [Pb] and an epoxy resin.

[0006]

In the present invention, as the rubber particles dispersed as a toughness improving component in the epoxy resin, a polymerizable monomer (A) containing an unsaturated carboxylic acid as an essential component is used as an alkyl group having 6 to 18 carbon atoms. Water-soluble or water-dispersible acid value of 20 obtained by polymerization in the presence of mercaptan (B).
0 or more terminal alkyl group-containing polymer [Pa] and /
Or using a reactive surfactant consisting of a salt thereof as an emulsifier,
(Meth) acrylic acid ester-based polymer particles [Pb] having a glass transition temperature of 20 ° C. or lower, which are obtained by emulsion polymerization of a (meth) acrylic acid ester-based monomer, are used.

That is, in the present invention, as the emulsifier in the production of the (meth) acrylic acid ester-based polymer particles [Pb], the reactivity of the specific terminal alkyl group-containing polymer [Pa] and / or its salt is shown. It has one characteristic in using a surfactant, and effectively exhibits the function as an emulsifying agent for emulsion polymerization, and as described in detail later, (meth) acrylic acid ester-based polymer particles [P
In order to give b] reactivity with an epoxy resin, a water-soluble or water-dispersible terminal alkyl group-containing polymer [Pa] having an acid value of 200 or more must be used, and its molecular weight is 300. ~ 7000, especially 1000-4000
The range of is preferable.

The unsaturated carboxylic acid used in the synthesis of the terminal alkyl group-containing polymer [Pa] (hereinafter sometimes simply referred to as the polymer [Pa]) is hydrophilic by introducing a carboxyl group into the polymer. (Meth) acrylic acid ester-based polymer particles obtained by emulsion polymerization [P
It is used to introduce a functional group capable of reacting with an epoxy resin into b] so that the emulsifier does not remain as an unreacted low molecular weight product in the modified epoxy resin. And the type thereof is not particularly limited as long as it has a polymerizable unsaturated group, but preferable examples include (meth) acrylic acid, unsaturated monocarboxylic acids such as crotonic acid, maleic acid, fumaric acid, and itaconic acid. And unsaturated dicarboxylic acids, and half-esterified products of these unsaturated dicarboxylic acids. These may be used alone or in combination of two or more.

As the polymerizable monomer component (A), only the unsaturated carboxylic acid as described above may be used, or if necessary, a suitable amount of a polymerizable monomer other than the unsaturated carboxylic acid may be used in combination. The polymerizable monomer that can be used in combination is not particularly limited as long as it has a copolymerizability with an unsaturated carboxylic acid,
For example, styrene derivatives such as styrene, vinyltoluene, α-methylstyrene, chloromethylstyrene, styrenesulfonic acid and salts thereof; (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth) acrylamide, N, (Meth) acrylamide derivatives such as N-dimethyl (meth) acrylamide;

It is synthesized by esterification reaction of (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate with an alcohol having 1 to 18 carbon atoms ( (Meth) acrylic acid ester; hydroxyl group-containing (meth) such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylic acid, monoester of (meth) acrylic acid and polypropylene glycol or polyethylene glycol Acrylic esters;

Examples thereof include ethyl (2-methacrylate) 2-sulfonate and salts thereof, vinyl sulfonate and salts thereof, vinyl acetate, and (meth) acrylonitrile. One or more of these can be used. The amount of the above polymerizable monomer other than the unsaturated carboxylic acid to be used in combination should be taken into consideration so that the resulting terminal alkyl group-containing polymer [Pa] does not have an acid value of less than 200. Further, it is preferable to adjust the kind and amount of the obtained terminal alkyl group-containing polymer [Pa] in consideration of compatibility with a polymer produced when emulsion polymerization is performed using the polymer as an emulsifier.

Next, the terminal alkyl group-containing polymer [P
Examples of the alkyl mercaptan (B) used in the production of a] include n-hexyl mercaptan and n.
-Octyl mercaptan, n-dodecyl mercaptan,
Examples thereof include t-dodecyl mercaptan, cetyl mercaptan, and stearyl mercaptan. These can be used alone or in combination of two or more.

The alkyl mercaptan (B) is used to introduce an alkyl group at the terminal of the polymer [Pa] to impart surface activity, and in the alkyl mercaptan having less than 6 carbon atoms, It is not preferable because the stability during emulsion polymerization and the storage stability deteriorate. The amount of the alkyl mercaptan (B) to be used should be determined according to the desired molecular weight of the polymer [Pa], but usually 2 to 300 parts by weight relative to 100 parts by weight of the polymerizable monomer component (A). Used in the range of.

As the polymerization initiator used for the polymerization of the polymerizable monomer component (A), well-known oil-soluble or water-soluble polymerization initiators can be used, but the terminal alkyl group-containing polymer [Pa] is used efficiently. For good production, the amount used is preferably 1 mol or less, more preferably 0.1 mol or less, relative to 1 mol of the alkyl mercaptan (B).

The polymer [Pa] is obtained by bulk polymerization, solution polymerization,
It can be produced by any method such as suspension polymerization. The polymerization temperature is usually 50 to 150 ° C., and the polymerization time is 1 to 8
Time is common. As the solvent used in the solution polymerization, the polymerizable monomer component (A), the alkyl mercaptan (B), and the radical polymerization initiator are all dissolved,
In addition, any kind may be used as long as it does not inhibit radical polymerization.

The polymer [Pa] itself has a sufficient surface-active ability, but when it is used as a salt of the polymer [Pa] by neutralizing a part or all of the carboxyl groups, it serves as an emulsifier. The effect becomes even better. Examples of the neutralizing agent used here include alkali metal compounds such as sodium hydroxide and potassium hydroxide; alkaline earth metal compounds such as calcium hydroxide and calcium carbonate; ammonia; monomethylamine, dimethylamine, trimethylamine, mono Water-soluble organic amines such as ethylamine, diethylamine, triethylamine, monopropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, and diethylenetriamine are listed, and one or more selected from these groups. Can be used. However, when the metal ion in the cured epoxy resin becomes a problem, it is preferable to use ammonia or low-boiling amines such as monomethylamine, dimethylamine and trimethylamine, which scatter at room temperature or by heating.

Next, as the monomer (C) used for producing the (meth) acrylic acid ester-based polymer particles [Pb], methyl, ethyl, propyl, isopropyl, butyl, isobutyl, octyl, 2- A (meth) acrylic acid ester which is an ester compound of a (meth) acrylic acid with a linear or branched aliphatic alkyl alcohol having 1 to 18 carbon atoms such as ethylhexyl, lauryl, stearyl or cyclohexyl or an alicyclic alkyl alcohol. Kinds; hydroxyethyl (meth) acrylate,
Hydroxypropyl (meth) acrylate, hydroxyl group-containing unsaturated monomers such as monoesters of (meth) acrylic acid with polypropylene glycol or polyethylene glycol; epoxy group-containing unsaturated monomer such as glycidyl (meth) acrylate Body; Unsaturated aziridinyl group-containing monomers such as (meth) acryloyl aziridine and (meth) acryloyloxyethyl aziridine;

2-isopropenyl-2-oxazoline,
Oxazoline group-containing unsaturated monomers such as 2-vinyl-2-oxazoline; (meth) acrylic acid and ethylene glycol, 1,3-butylene glycol, 1,6-hexane glycol, neopentyl glycol, polyethylene glycol, polypropylene Polyfunctional (meth) acrylic acid esters containing two or more polymerizable unsaturated groups in the molecule such as esters with polyhydric alcohols such as glycol and trimethylolpropane; and allyl (meth) acrylate. These may be used alone or in combination of two or more kinds, and further, other copolymerizable monomers such as styrene, vinyltoluene, acronitrile, methacrylonitrile, vinyl acetate, It is also possible to copolymerize an appropriate amount of divinylbenzene, diallyl phthalate, etc.

In producing the (meth) acrylic acid ester-based polymer particles [Pb], the monomer (C) is used so that the glass transition temperature of the obtained polymer particles [Pb] is 20 ° C. or lower. It is necessary to consider the type and combination of. If the glass transition temperature of the polymer particles [Pb] exceeds 20 ° C., a sufficient toughness improving effect cannot be obtained. A more preferable glass transition temperature of the polymer particles [Pb] is 0 ° C. or lower in the sense that the toughness of the obtained epoxy resin composition is further improved.

The lower the glass transition temperature of the polymer particles [Pb], the higher the toughness improving effect. However, the lower limit of the glass transition temperature of the polymer particles [Pb] obtained by polymerizing a (meth) acrylic acid ester-based monomer currently on the market is about −80 ° C. It is difficult to obtain (meth) acrylic acid ester-based polymer particles having a temperature.

When a monomer (C) having a functional group capable of reacting with a carboxyl group is used as the (meth) acrylic acid ester-based monomer (C), the above-mentioned emulsifier having a carboxyl group ( Since the (meth) acrylic acid ester-based polymer particles [Pb] are bonded more firmly, the toughening effect on the epoxy resin is further enhanced. As such a monomer (C), among those exemplified as the above-mentioned monomer (C), epoxy group-containing polymerizable monomers, aziridinyl group-containing polymerizable monomers, oxazoline group-containing polymerizable monomers Monomers are preferred.

Introducing an appropriate cross-linking structure into the (meth) acrylate polymer particles [Pb] is
It is effective in increasing the toughness of epoxy resin.
As the polymerizable monomer (C) capable of introducing such a crosslinked structure, among the monomers exemplified as the monomer (C), a polyfunctional compound having two or more polymerizable unsaturated groups in the molecule. Preferred examples thereof include a (meth) acrylic acid ester, divinylbenzene, diallyl phthalate, and allyl (meth) acrylate. However, the amount used
It should be suppressed to about 0.5 to 10 parts by weight, and if it exceeds 10 parts by weight, the toughening effect tends to decrease.

There are no particular restrictions on the emulsion polymerization method,
All conventionally known emulsion polymerization methods can be applied. For example, a method in which the above-mentioned terminal alkyl group-containing polymer [Pa] acting as an emulsifier is mixed together with the above-mentioned polymerizable monomer (C), a polymerization catalyst, and water for polymerization, or a so-called monomer dropping method or pre-emulsion method. Furthermore, the (meth) acrylic acid ester-based polymer particles [Pb] can be synthesized by a method such as a seed polymerization method or a multi-stage polymerization method. Polymerization is usually 0 to 100 ° C, preferably 50 to 80 ° C
The polymerization time of about 1 to 10 hours is sufficient.

The amount of the polymer [Pa] used as an emulsifier is not particularly limited, but is preferably 0.5 to 10 parts by weight, more preferably 1 to 3 parts by weight with respect to 100 parts by weight of the polymerizable monomer (C). It is a range of parts. However, in the production process of the epoxy resin composition as described below, the defoaming agent used for the purpose of suppressing foaming due to the emulsifier generated when water is distilled off reduces the physical properties of the epoxy resin cured product as an impurity. The cause is that the amount of polymer [Pa] used is 3
This is because if the amount is controlled to be not more than the weight part, almost no bubbles are generated even during dehydration, so that it is not necessary to use an antifoaming agent and the physical properties of the cured epoxy resin product are not deteriorated.

As the polymerization catalyst used in the emulsion polymerization, all known catalysts can be used, but if there is a possibility that an alkali metal, chloride ion, etc. may adversely affect the cured epoxy resin, hydrogen peroxide, peracetic acid, diamine, etc. It is desired to use a polymerization catalyst such as -t-butyl peroxide and 4,4'-azobis (4-cyanopentanoic acid).

There are no particular restrictions on the epoxy resin used in the present invention, and any known epoxy resin can be appropriately selected and used according to the required characteristics. For example, glycidyl ethers of phenols such as bisphenol A, bisphenol F, phenol novolac, cresol novolac and brominated bisphenol A; glycidyl ethers of alcohols such as butanol, butanediol, polyethylene glycol, polypropylene glycol; hexahydrophthalic acid, dimer Examples thereof include glycidyl esters of acids such as acids. These may be used alone or in combination of two or more.

Among them, a bisphenol type epoxy resin having a bisphenol skeleton such as bisphenol A and bisphenol F, and a mixture of these bisphenol type epoxy resin and an aliphatic epoxy compound such as triglycidyl ether of glycerin have both heat resistance and adhesive strength. It is particularly preferably used in order to satisfy the performance.

In producing the modified epoxy resin according to the present invention, the following method is recommended in terms of simplifying the process and preventing impurities from entering. That is, this is a method in which the emulsion of the (meth) acrylic acid ester-based polymer particles [Pb] is directly mixed with the epoxy resin and water is removed with stirring under normal pressure or reduced pressure.

In the methods proposed so far, a coagulant containing a metal is added, or the cloud point of a nonionic emulsifier is used to coagulate and precipitate rubber particles in an emulsion state, followed by drying and then epoxy. It requires a plurality of steps of dispersing in a resin, and not only the steps are complicated, but also metal ions may be mixed in the composition to deteriorate the physical properties of the cured epoxy resin.

However, when the above-mentioned production method defined in the present invention is adopted, it is possible to easily obtain a resin composition in which the (meth) acrylic acid ester polymer particles [Pb] are uniformly dispersed in the epoxy resin in one step. You can In this case, if an ordinary low-molecular weight emulsifier is used as an emulsifier and a similar dispersion is to be obtained, bubbles are significantly generated when water is removed and overflows from the container, so that dehydration becomes substantially impossible. .

The reason why the above-mentioned simple production method can be realized in the present invention is that the polymer [Pa] used as an emulsifier is used.
Has a high molecular weight and is strongly bound to the polymer particles [Pb], and therefore has less bubbles in the dehydration step, and the polymer [Pa] has reactivity with the epoxy resin. This is probably because the dispersibility is also good.

In the production of the modified epoxy resin, the emulsion of the epoxy resin and the (meth) acrylic acid ester-based polymer particles [Pb] is put into a container equipped with a stirrer and a water removing port, and the temperature is preferably 0 to 150 ° C. Is 50-13
Water may be removed with stirring at 0 ° C. under reduced pressure of 1 mmHg to 760 mmHg or normal pressure, preferably reduced pressure of 30 mmHg to 600 mmHg.

The amount of the (meth) acrylate polymer particles [Pb] dispersed in the epoxy resin is preferably 1 part by weight to 50 parts by weight, more preferably 100 parts by weight in terms of solid content, based on 100 parts by weight of the epoxy resin. Is 2 to 30 parts by weight. (Meth) acrylic acid ester-based polymer particles [P
When the amount of b] is less than 1 part by weight, the toughening effect is hardly obtained, while when it exceeds 50 parts by weight, the viscosity of the modified epoxy resin becomes too high and the original properties of the epoxy resin are impaired.

As described above, the adhesive composition of the present invention contains, as an essential component, a modified epoxy resin obtained by uniformly dispersing (meth) acrylate polymer particles [Pb] in the epoxy resin. If desired, known epoxy resin curing agents, curing accelerators, modifiers, fillers, flame retardants, reinforcing materials, surface treatment agents, thixotropy imparting agents, pigments and the like may be used in combination.

Known epoxy resin curing agents include linear aliphatic amines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine and diethylaminopropylamine; various polyamides having different amine values; menthenediamine and isophoronediamine. Alicyclic amines such as bis (4-aminocyclohexyl) methane; aromatic amines such as m-xylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and m-phenylenediamine; phthalic anhydride, tetrahydrophthalic anhydride, hexahydro Phthalic anhydride, methyl tetrahydro phthalic anhydride, methyl hexahydro phthalic anhydride, methyl nadic acid anhydride, dodecyl succinic anhydride, pyromellitic acid anhydride, methyl cyclohexene tetracarboxylic acid anhydride, Water trimellitic acid, acid anhydrides such as polyazelaic anhydride; phenol novolak,
Compounds containing phenolic hydroxyl groups such as cresol novolac; polymercaptans;

Anionic polymerization catalysts such as 2,4,6-tris (dimethylaminomethyl) phenol and 2-ethyl-4-methylimidazole; Cationic polymerization catalysts such as BF ₃ monoethylamine complex; Dicyandiamide, amine adduct, hydrazide , Amidoamine, blocked isocyanate, carbamate, ketimine, aromatic diazonium salt, guanidine derivative, triazine derivative, imidazole compound, N, N′-dialkylurea derivative,
Latent curing agents typified by N, N′-dialkylthiourea derivatives and the like can be mentioned, and one kind or two or more kinds thereof can be used.

Examples of the modifier include maleimide compounds such as 4,4'-methylenedianiline bismaleimide. Fillers include calcium carbonate, barium carbonate,
Examples thereof include carbonates or sulfates of alkaline earth metals such as magnesium carbonate, calcium sulfate, barium sulfate or magnesium sulfate, silica, clay, titanium oxide, kaolin, talc, aluminum powder and the like.

As the stabilizer, metal soaps (eg calcium stearate, aluminum stearate etc.), inorganic acid salts (eg dibasic phosphite, dibasic sulfate etc.) and organometallic compounds (eg : Dibutyltin dilaurate, dibutyltin malate, etc.) and the like. As rust preventive pigments, chromates (eg, strontium chromate, barium chromate), basic lead sulfate,
Examples include cyanamide lead. Examples of the thixotropic agent include finely divided silica, organic bentonite, and ultrafine calcium carbonate. When the adhesive composition contains water, a relatively small amount of powder of calcium oxide, magnesium oxide, diatom oxide or the like can be added and mixed as an adsorbent of water. Further, a coloring agent such as carbon black or red iron oxide can be optionally added.

Examples of the flame retardant include aluminum hydroxide, antimony trioxide, red phosphorus and the like. As the reinforcing material, a woven cloth or a non-woven cloth composed of organic fibers or inorganic fibers such as glass fiber, polyester fiber, polyamide fiber and alumina fiber,
Examples include matte, paper, and combinations thereof.

The adhesive composition according to the present invention contains the above-mentioned components in a three-roll, kneader mixer, paddle mixer,
It can be obtained by kneading by a conventional means with a kneading machine typified by a planetary mixer, a disper mixer and the like.

When the adhesive composition of the present invention is used as an industrial adhesive, for example, the composition is roll-kneaded at 110 ° C to 50 ° C to form a uniform mixture, which is then processed into a liquid or sheet form. One can be used as an adhesive. Alternatively, the composition may be dissolved in a solvent such as dimethylformamide, methyl cellosolve, or acetone, and directly applied to an adherend to be used, and this solution may be used as a reinforcing material such as glass fiber. Impregnate and 5 at 150-180 ℃
A prepreg obtained by drying for 10 minutes can also be used as an adhesive.

[0042]

The modified epoxy resin contained in the adhesive composition of the present invention is one in which uniform (meth) acrylic acid ester-based polymer particles are uniformly dispersed in the epoxy resin. Unlike the conventional toughening epoxy resin with added type rubber, there is almost no change in the toughening effect due to the curing conditions, and the rubber component dissolved in the epoxy resin is virtually zero, so the heat resistance is also reduced. I can't. Moreover, as compared with the one toughened by the conventional rubber particle emulsion addition method, since there is no shell component, a small amount of the compound shows an excellent toughening effect.

Further, by using a polymer having a terminal alkyl group having a specific structure as an emulsifier, foaming during dehydration during the production of an epoxy resin composition can be suppressed, and the production becomes extremely simple. Further, the terminal alkyl group-containing polymer used as the emulsifier has reactivity with the epoxy resin, and since these are also distributed in the epoxy resin in a bound state, the obtained epoxy resin composition is tough and It has excellent water resistance (moisture resistance) and adhesiveness.

Therefore, the adhesive composition of the present invention has the following properties:
In particular, it has excellent peeling strength and bending strength, and also has heat resistance, water resistance, and oil surface adhesiveness, and exhibits excellent performance in various applications.

The adhesive composition of the present invention is for electric / electronic use,
It can be widely used for automotive plywood, woodworking, construction, civil engineering, bookbinding, packaging lamination, etc. For example, in the electrical and electronic fields, as a metal foil, a metal plating film, a bonding agent such as a conductor paste layer when forming an electric circuit, a dip coating agent, a partial insulating agent for the purpose of protecting hybrid ICs, etc. It can be used for coating, coating of hybrid IC, and the like, potting agent for electronic parts, fixing agent for internal wiring of refrigerators, components, and the like.

In the automobile field, automobile body hemming, automobile electrical equipment-related adhesion, brake lining, clutch,
It can be used for bonding fenders, disc pads, rear combination lamps, motor magnets, etc. In the field of sports and leisure, there are applications as skis / water skis, surfs, hang-riders, and structural adhesives for small aircraft.

[0047]

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. In the examples, "%" and "parts" mean "% by weight" and "parts by weight" unless otherwise specified.

Reference Example 1 (Production of emulsifier) 180 parts of isopropyl alcohol was charged into a flask equipped with a stirrer, a reflux condenser, a nitrogen introducing tube, a thermometer, and a dropping funnel, and heated to 81 ° C. while blowing nitrogen. The isopropyl alcohol was refluxed for 10 minutes. Next, 53.6 parts of acrylic acid and 16.5 lauryl methacrylate prepared in advance.
Part, Blemmer PE200 (polyethylene glycol monomethacrylate manufactured by NOF CORPORATION) 91 parts, 13.7 parts of n-dodecyl mercaptan and 0.4 parts of 2,2'-azobisisobutyronitrile (AIBN) The mixture was added dropwise into the flask over 2 hours. After completion of the dropping, aging was carried out for 1 hour under reflux to obtain a solution of a terminal alkyl group-containing polymer [Pa-1] having a solid content of 49.1%.
The acid value of this polymer [Pa-1] is 239, and the number average molecular weight is
It was 2300.

Reference Example 2 (Production of Emulsifier) As a polymerizable monomer mixture, 70 parts of methacrylic acid, 91 parts of Bremmer PE200 (same as above), n-dodecyl mercaptan
Polymerization was carried out in the same manner as in Reference Example 1 except that a polymerizable monomer mixture consisting of 17 parts and AIBN 0.4 part was used.
Polymer containing a terminal alkyl group having a solid content of 49.5% [Pa-
2] solution was obtained. The acid value of this polymer [Pa-2] is 25.
6, the number average molecular weight was 2,100.

Reference Example 3 (Production of Emulsifier) As a polymerizable monomer mixture, 145 parts of acrylic acid, 16 parts of styrene, 18 parts of stearyl mercaptan and AIBN.
Polymerization was conducted in the same manner as in Reference Example 1 except that 0.4 part of the polymerizable monomer mixture was used to obtain a solution of the terminal alkyl group-containing polymer [Pa-3] having a solid content of 49.6%. This polymer [Pa-3] has an acid value of 630 and a number average molecular weight of 28.
00.

Examples 1 to 5 and Comparative Examples 1 to 7 (1) Production of (meth) acrylic acid ester-based polymer A flask equipped with a dropping funnel, a stirrer, a nitrogen introducing tube, a thermometer and a reflux condenser was pure. 63 parts of water was charged and heated to 70 ° C while gently blowing nitrogen gas. On the other hand, 85 parts of ethyl acrylate, 10 parts of methyl methacrylate, 5 parts of glycidyl methacrylate, 4.1 parts of the solution of the terminal alkyl group-containing polymer [Pa-1] obtained in Reference Example 1, 0.5 parts of 28% ammonia water, 36 parts of ion-exchanged water was thoroughly stirred in advance and charged into the above dropping funnel as a fully emulsified pre-emulsion.

Next, 4,4'-azobis (4
-Cyanopentanoic acid) 8 parts of a 5% aqueous solution of ammonia neutralization was injected, and then the above pre-emulsion was added dropwise from a dropping funnel over 3 hours and 30 minutes. After the dropping was completed, the dropping funnel was washed with 10 parts of ion-exchanged water so that the pre-emulsion did not remain, and the washing solution was added into the flask. During the dropping of the pre-emulsion, the temperature is maintained at 70 to 75 ° C, and after the dropping is completed, the mixture is stirred at the same temperature for 2 hours to terminate the polymerization, and the (meth) acrylic acid ester-based polymer emulsion with a nonvolatile content of 46.0% [1 ] Was obtained.

Further, a (meth) acrylic acid ester-based polymer emulsion was prepared in the same manner as described above except that the terminal alkyl group-containing polymer solution used as the emulsifier and the polymerizable monomer component were changed to those shown in Table 1. [2] to [5] and comparative emulsions [C1] to [C4] were obtained. still,
In Table 1, the glass transition temperature of the emulsion polymer particles is shown as Per after the water is volatilized and removed from the emulsion.
Kind Elmer's differential scanning calorimeter "DSC-"
7 ”.

[0054]

[Table 1]

(2) Production of modified epoxy resin (meth) acrylic acid ester-based polymer emulsions [1] to [5] obtained in the above (1) and comparative emulsion [C
1] to [C4] were placed in a flask equipped with a stirrer, a nitrogen introduction tube, and a condenser, and ion-exchanged water was added to adjust the nonvolatile content concentration to 30%. A certain amount of Epicoat 82
8 (Bisphenol A type epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.) was added and stirred to obtain a uniform viscous liquid. Then, the temperature was raised to 70 ° C., and finally the pressure was reduced to 50 mmHg to remove water while gradually increasing the degree of pressure reduction. Then, the mixture was heated to 130 ° C. to completely remove water, and the carboxyl group in the emulsifier (terminal alkyl group-containing polymer) was preliminarily reacted with the epoxy resin.

Table 2 shows the constitution of the modified epoxy resins [I] to [V] thus obtained (the measuring method is as follows). In addition, in the case of using the comparative emulsions [C1] to [C3], the foaming during dehydration was so strong that the water could not be removed until the end.
As a defoaming agent, San Nopco 8034L (manufactured by San Nopco) is used.
After adding 3 parts, the same operation was performed to synthesize modified epoxy resins [I] to [VI] for comparison.

<Water content in modified epoxy resin> Karl-Fis
The amount of water in the modified epoxy resin was measured using a cher Moisture Meter (KYOTO ELECTRONICS MKS-3p). <Reaction rate of carboxyl group in emulsifier> By titration with 0.1N-NaOH, the amount of carboxyl group per 1 g of (meth) acrylic acid ester-based polymer particles before and after dispersion of epoxy resin was measured, and the reaction rate was calculated from the ratio. It was calculated. [(Amount of carboxyl group before dispersion (mol / g) -Amount of carboxyl group after dispersion (mol / g)) / Amount of carboxyl group before dispersion (mol / g)]
× 100 = Reaction rate of emulsifier carboxyl group (%)

<Epoxy equivalent> HCl / THF was reacted, and excess HCl was measured by back titration. (3) Epoxy adhesive composition (adhesion of mild steel plate) <Adhesion test> The modified epoxy resin obtained in (2) above was mixed with a filler and a curing agent at a ratio shown in Table 2 through a three-roll mill. An adhesive composition was prepared by using the adhesive composition. The adherend is 1.5 mm thick
A cold-rolled steel plate (T-type peeling test: 0.5 mm) washed and degreased with acetone was used. Adhesive curing at 150 ° C
It was carried out by heating for 0.5 hour, and the results are also shown in Table 2.

Tensile shear strength : Performed according to JIS K 6850. Tensile speed 10 mm / min. T-type peel strength : Performed according to JIS K 6854. Pulling speed 50 mm / min. 80 ° C hot water resistance : The adhesive test piece was immersed in 80 ° C hot water for 24 hours, and then the tensile shear strength was measured at room temperature (23 ° C) to examine the hot water resistance. 80 ° C. heat resistance : The adhesive test piece was measured for tensile shear strength under the temperature condition of 80 ° C. to examine the heat resistance. Oil surface adhesion : Japan Test Panel Industry Co., Ltd.
The cold-rolled steel sheet manufactured as described above was used as it was without degreasing, the T-type peel strength was measured, and the oil surface adhesiveness was examined.

[0060]

[Table 2]

Description of compounds in Table 2 (1) Epicoat 807: Bisphenol F type epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd. (2) ADEKA GLYSILOL ED-503: Asahi Denka Kogyo Co., Ltd.
Aliphatic diglycidyl ether (3) ADEKA GLYSILOL ED-505: Asahi Denka Kogyo Co., Ltd.
Triglycidyl ether of trimethylolpropane (4) CTBN1: Sold by Ube Industries, Ltd. HYCAR C
TBN 1300 × 8 (5) CTBN2: Above HYCAR CTBN 1300 × 8
The carboxyl groups of the above were pretreated with Epicoat 828 (at 150 ° C. for 3 hours). As is clear from Table 2, the adhesive composition of the present invention is
There is little decrease in tensile shear strength after immersion in hot water at 80 ° C, and T
It can be seen that the mold peeling strength is also very excellent.

It is also found that the heat-resistant tensile strength and the oil surface adhesive strength are also excellent. Examples 6 to 10 and Comparative Examples 8 to 10 (4) Epoxy adhesive composition (electric circuit board) Modified epoxy resins [I] to [IV] produced in Examples 1 to 5
[Used as a 35 wt% xylene / methyl ethyl ketone mixed solution (mixing weight ratio 1: 1)], epoxy equivalent 1750-22
A bisphenol A type epoxy resin of 00 (used as a 50 wt% xylene or methyl ethyl ketone solution) with 60 wt% of fused alumina (average particle size 1 to 5 μm) dispersed through three rolls, colloidal silica as a thixotropic material (Used as a 40 wt% xylene solution)
Then, the curing agent produced by the method described below was kneaded with a disper so that the composition shown in Table 3 was obtained, to obtain an epoxy adhesive composition. In Comparative Example 9, Nipol10 manufactured by Nippon Zeon Co., Ltd.
72B is (NBR), and Comparative Example 10 is C sold by Ube Industries.
TBN (see Table 1) was compounded as a rubber latex. Note that Example 10 was a clear type adhesive (no filler, no thixotropic material was added).

<Preparation of curing agent> 500 equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen sealing capillary.
An ml 4-necked flask was used. Diamine methylenebis (aniline) and butyl cellosolve were charged in this flask at a ratio of diamine: butyl cellosolve = 2: 1 (weight ratio), sealed with nitrogen, and heated and dissolved at 70 ° C. On the other hand,
Bisphenol A type epoxy resin (epoxy equivalent 187)
Butyl cellosolve was dissolved at a ratio of epoxy resin: butyl cellosolve = 1: 2, and this solution was added dropwise to the 4-neck flask over 1 hour to react the diamine with the epoxy resin (diamine: epoxy resin = 2: 1). ). Although this reaction is an exothermic reaction, the temperature was controlled so as not to exceed 120 ° C. After the exothermic reaction was completed, the mixture was heated to 130 ° C. and stirred for 1 hour to complete the reaction and obtain a curing agent. Curing agents were used in Examples 6-10 and Comparative Examples 8-10 below, respectively.

[0064]

[Table 3]

An aluminum plate having a thickness of 1 mm was used as a substrate, and an electrolytic copper foil (thickness: 35 μm) was used as a metal foil. Each epoxy-based adhesive composition obtained is applied to one surface of the substrate,
B-stage (semi-cured state) was performed at the temperature and time shown in Table 4 by placing in a hot-air circulation type constant temperature bath. At this time, the thickness of the adhesive was 100 μm. After that, lay a metal foil (electrolytic copper foil: thickness 35μm) on the adhesive and 180 ℃
The heat-pressing (pressure 10 kgf / cm ² ) was used to make the adhesive C-stage (completely cured) to obtain an electric circuit board. The heat pressing time was all 15 minutes. The adhesive of Example 6 was cured under the three conditions of 6-1, 6-2, and 6-3, as shown in Table 4.

For each electric circuit board, the room temperature peel strength, surface resistance, volume resistance and surface resistance after the electrical corrosion test were
It was measured by the test method of JIS standard C6481 (copper clad laminate test method for printed wiring boards). The 150 ° C peel strength is
After soaking in oil at 150 ° C for 5 minutes, measure by the test method according to the JIS standard, and the electrical corrosion test is DC 100V
Was applied for 500 hours at a temperature of 60 ° C. and a humidity of 95%. The results are shown in Table 4.

[0067]

[Table 4]

As is clear from Table 4, the epoxy adhesive composition of the present invention is excellent in peel strength at room temperature and 150 ° C. In addition, electrical characteristics (resistance value) compared to those with NBR or CTBN added to increase peel strength
It turns out that it is excellent.

Examples 11 to 14 and Comparative Examples 11 to 12 (5) Epoxy adhesive composition (for automobile) A predetermined weight part of each raw material shown in Table 5 was charged and kneaded and defoamed to obtain an adhesive composition. It was At this time, 20 wt% of the modified epoxy resin, the latent curing agent, the filler, the stabilizer, the rust preventive pigment and the plasticizer used was mixed and dispersed (component 1). On the other hand, while a vinyl chloride polymer plastic sol consisting of a vinyl chloride polymer and the remaining plasticizer was prepared in a planetary mixer, after blending and kneading component 1, a thixotropic agent was blended and kneaded, and the pressure was reduced. Defoamed.

[0070]

[Table 5]

The physical properties of the obtained adhesive were evaluated as follows, and the results are shown in Table 6. (1) Storage stability of viscosity The viscosity was measured using a thin-tube extrusion viscometer at a shear rate of 62 sec at 35 ° C.
The value was ^-1 . Storage stability 40% adhesive composition
When the rate of change in viscosity was kept within 30% after holding at 7 ° C for 7 days, it was marked with O, and when it exceeded 30%, it was marked with X. (2) Adhesive strength Use an oil surface steel plate (SPC-D steel plate) coated with rust preventive oil
The mixture was heat-cured at 10 ° C. for 10 minutes and 170 ° C. for 20 minutes, and the shear adhesive strength and peel adhesive strength were measured at 23 ° C. according to JIS K6850 and JIS K6854, respectively. The adhesive strength when cured at 150 ° C for 10 minutes was used as a guide for temporary fixing.

(3) Flexibility An adhesive was applied to the above oil surface steel sheet in a shape of 150 × 25 × 1 mm, followed by heat curing at 170 ° C. for 20 minutes, and the steel sheet was applied at room temperature using a mandrel having a diameter of 1 inch. Bend to an angle of 90 °. In this case, the case where the cured adhesive layer was not broken was marked with ◯, and the case where it was broken was marked with x. (4) Adhesion durability 50 ° C for the 170 ° C, 20-minute heat-curing test piece in (2) above.
After storing at 95% RH or less for 30 days, the adhesive strength was measured at 23 ° C, and when the strength was 80% or more of the initial strength, it was marked with ◯, and when it was less than 80%, it was marked with x.

[0073]

[Table 6]

As shown in Table 6, it was confirmed that the adhesive compositions of the present invention shown in Examples satisfy the characteristics required for an adhesive for automobile hemming.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masuji Izumibayashi 5-8 Nishiomitabicho Suita City, Osaka Prefecture Nippon Shokubai Central Research Institute (56) Reference JP-A-3-88813 (JP, A ) JP-A-2-124988 (JP, A) JP-A-1-234416 (JP, A) JP-A-63-125589 (JP, A)

Claims (3)

(57) [Claims] 1. A water-soluble compound obtained by polymerizing a polymerizable monomer component (A) containing an unsaturated carboxylic acid as an essential component in the presence of an alkylmercaptan (B) having 6 to 18 carbon atoms. A water-dispersible terminal alkyl group-containing polymer [Pa] having an acid value of 200 or more and / or a reactive surfactant composed of a salt thereof is used as an emulsifier, and a (meth) acrylic acid ester-based monomer (C) is added. An adhesive composition containing (meth) acrylic acid ester-based polymer particles [Pb] having a glass transition temperature of 20 ° C. or lower, which is obtained by emulsion polymerization, and an epoxy resin. 2. The adhesive composition according to claim 1, wherein the (meth) acrylic acid ester-based polymer particles [Pb] have a crosslinked structure. 3. The adhesive composition according to claim 1 or 2, wherein the (meth) acrylic acid ester-based polymer particles [Pb] have a functional group capable of reacting with a carboxyl group in the molecule.