CA1236618A

CA1236618A - Adhesive agent containing microcapsules

Info

Publication number: CA1236618A
Application number: CA000445200A
Authority: CA
Inventors: Yuriko Igarashi; Masaaki Takahashi
Original assignee: Kureha Corp
Current assignee: Kureha Corp
Priority date: 1983-01-14
Filing date: 1984-01-12
Publication date: 1988-05-10
Also published as: AU2307484A; FR2539326A1; KR840007247A; ES528860A0; AU550246B2; DE3401056A1; JPH0222775B2; GB2133374B; DE3401056C2; FR2539326B1; JPS59129281A; GB2133374A; KR870000700B1; GB8400939D0; BE898677A; ES8505397A1; IT8419154A0; IT1206123B

Abstract

TITLE OF THE INVENTION:
ADHESIVE AGENT CONTAINING MICROCAPSULES

ABSTRACT OF DISCLOSURE:
Disclosed herein are an adhesive agent containing microcapsules, comprising said microcapsules consisting essen-tially of a core substance of at least one of the components constructing said adhesive agent and as a material for the membrane of said microcapsule, an aminoplast preliminarily treated by a modifier, and a medium consisting of the other components constructing said adhesive agent, said microcapsules dispersing in said medium and said adhesive agent being the type of chemical reaction or the type of solvent activation, and a process for preparing the same.

Description

;6~3 BACKGROUND OF THE INVENTION:
..
The present invention relates to an adhesive agent con-twining micro capsules, and more in detail, relates to an adhesive agent of a chemical reaction type or of an activation-by-solvent type both containing micro capsules. Still more in detail, the present invention relates to an adhesive agent containing micro-capsules, comprising said micro capsules consisting essentially of a core substance of at least one of the components constructing said adhesive agent and as a material for the membrane of said micro capsule, an aminoplast preliminarily treated by a modifier, and a medium consisting of the other components constructing said adhesive agent, said micro capsules dispersing in said medium and said adhesive agent being the type of chemical reaction or the type of solvent activation, and to a process for preparing an adhesive agent containing micro capsules, the pharaoh process eel the step of dispersing micro capsules con-sitting essentially of the core substance of at least one of the components constructing the adhesive agent and a membranes material consisting essentially of an aminoplast treated by a modifier in the other components constructing the adhesive agent.
Adhesive agents are classified according to the method of ha/denlng hoFeof into the following four groups, I
:
' . ' - 1 -:~Z366~8 1) Adhesive agent of solvent-evaporation type:
After applying the agent, all the medium such as a solvent or water originally contained therein disappears from the applied agent by evaporation from the jointed end or absorb-lion to the materials to be adhered, and the thus formed membrane of the adhesive agent exhibits the maximum strength thereof.

2) Adhesive agent of chemical reaction type:
A hardened adhesive membrane is formed by a chemical reaction between the resin and the hardener or between the monomer (or oligomer) and the catalyst by mixing two separate components of the adhesive agent, one of which contains the resin or the monomer and the other of which contains the hardener or the catalyst.

3) Adhesive agent of solvent activation type:
After painting the adhesive agent on the surface of the body to be adhered and forming a dried membrane of the agent on the surface, a solvent is sprayed there onto to react tivate the painted surface of the membrane and then the other body to be adhered is placed on the thus reactivated surface of the membrane formed, thereby completing the adhesion.

4) Adhesive agent of hot melt type:
After applying the adhesive agent in the molten state thereof onto the surface of the bodies -to be adhered, the thus treated bodies are cooled so as to complete the adhesion.
The adhesive agent of chemical reaction type is composed of two mutually separated components which are mixed just before the application thereof and accordingly, such a type of adhesive agent has the demerits of inconvenience in lZ36618 application and of the limitation of the operation time after mixing the two components and of the necessity of discarding the remnant mixture of the two components.
While in the adhesive agent of solvent activation type, there are problems of environmental pollution and in industrial hygiene and safety because of the necessity of using a large amount of an organic solvent. I
In order to solve the above-mentioned demerits of some of the conventional adhesive agents, trials of encapsulating a component thereof have been carried out, and micro capsules provided with their membrane made of gelatin or polyamide have been proposed.
However, since the membranes wall of the hitherto proposed micro capsules are generally semipermeable or perforated microscopically, the component of the adhesive agent contained there within is apt to be extracted from the micro capsules, and because of the poor resistance of the membranes wall to an organic solvent such as alcohols, kittens and esters, there has been the same kind of demerit of extraction of the content in the micro capsule by such a solvent.
Particularly, in order to use micro capsules in an adhesive agent to which a solvent-resistance is specifically demanded, it is required that (1) the membranes wall of the micro capsule is particularly excellent in solvent-resistance and (2) the micro capsule itself is excellent in pressure-responsiveness to be easily broken by a minute increment of the I

pressure loaded thereon, and accordingly, it has been very difficult to put such an adhesive agent containing the micro-capsules in practical use. Namely, in order to improve the solvent resistance of the micro capsules to solvents, there have been tried a process of immersing the micro capsules in a basic substance to activate the surface of the micro capsules, a process of bringing the surface into contact with a vapour of an alpha-cyanoacrylate and a process of coating the micro-capsules with a substance resistant to the medium for dispersing the micro capsules in the adhesive agent to form the double-layered micro capsules. However, by such a process, the pressure necessary for braking the micro capsules on application becomes too large to use the thus treated micro capsules as the component of the adhesive agent.
An object of the present invention is to provided an adhesive agent containing the micro capsules excellent in solvent-resistance and in pressure-responsiveness, the adhesive agent solving the demerits of the conventional adhesive agents of chemical reaction type and of solvent activation type and being convenient and easy to be handled on application without the necessity of using an excessive amount of components of the adhesive agent.
SUMMARY OF THE INVENTION:
In the first aspect of the present invention, there is provided an adhesive agent containing micro capsules, comprising said micro capsules consisting essentially of a core substance I:

_ _ :~3661~3 of at least one of the components constructing said adhesive agent and, as a material for the Myron of said micro capsule, an aminoplast preliminarily treated by a modifier, and a medium consisting of the other components constructing said adhesive agent, said micro capsules dispersing in said medium and said adhesive agent being the type of chemical reaction or the type of solvent activation.
In the second aspect, there is provided a process for preparing an adhesive agent containing micro capsules 7 of the type of chemical reaction or the type of solvent activation, comprising dispersing minute liquid particles of at least one of the components of said adhesive agent in an aqueous dispersion of the components for forming an aminoplast, adding an acid catalyst to said aqueous dispersion, thereby bringing the prepolymer of said components for forming said aminoplast into polycondensation, adding a modifier to said aqueous dispersion during or after the completion of said pol~condensation, thereby forming said micro capsules encapsulating said at least one of said components within the membrane consisting essentially of said aminoplast modified by said modifier, collecting and drying the thus formed micro capsules, and dispersing said micro capsules in the other components constructing said adhesive agent containing micro capsules.

1~;~66~L~

DETAILED EXPLANATION OF THE INVENTION:
The characteristic of the present invention is in an adhesive agent containing micro capsules of the type of chemical reaction or the type of solvent activation, said micro capsules consisting essentially of (1) a core substance of one or more than one components of the adhesive agent, which is (are) to be encapsulated within the micro capsule and (2), as a material of the membrane of the micro capsule, an aminoplast treated pro-liminarily by a modifier in a system consisting essentially of the other components of the adhesive agent.
Namely, the adhesive agent containing the micro capsules, which is the type of chemical reaction or the type of solvent activation according to the resent invention takes a form of, in the case where it is the type of chemical reaction, namely, for instance, in the case where the component of the adhesive agent consisting essentially of a resin and a hardener or of a monomer or an oligomer and a catalyst, an adhesive agent containing the micro capsules encapsulating, as a component, the hardener or the catalyst (preferably as small as possible in amount) dispersed in the resin or the monomer and/or the oligomer.
In addition, in the case where the component is a multi-component system such as that consisting essentially of the monomer, the catalyst and the hardener, the micro capsules containing the catalyst or both the catalyst and the hardener are dispersed in the monomer in order to prevent the reaction between the catalyst and the monomer, and between the hardener and the monomer.

: ::

1~3~61~1 In this connection, not less than two components which do not mutually react may be separately encapsulated, however, it is preferable to encapsulate not less than two such components simultaneously, and in addition, the catalyst or the hardener may be encapsulated in a dissolved state in a solvent.
On the other hand, -the adhesive agent containing micro- I
capsules according to the present invention takes another form of, ¦
in the case where it is the type of solvent activation, an adhesive agent containing the micro capsules encapsulating a solvent necessary for dissolving and activating the resin which is to form the adhering membrane dispersed in a solution which contains the resin to be painted on the surface of a material to be adhered (hereinafter referred to as "the resin solution"). Consequently, according to the present invention, since it is necessary to encapsulate the smallest amount of the solvent necessary for activating the resin, the problem of the conventional adhesive agents of the type of solvent activation, caused by the use of a large alienate of a solvent, can be solved by this type of adhesive agent.
The important matter in encapsulating at least one of the components of the adhesive agent is that the membranes wall forming the micro capsule is excellent both in solvent-resistance and in pressure-responsiveness.
As a result of the present inventors' studies for obtain-in the material for forming a membranes wall of the above-mentioned specificities, it has been found by them that an amino-plats preliminarily treated by a modifier is suitable as the 1~3~618 above-mentioned material. The "aminoplast" herein mentioned means a resin obtained by bringing at least one prepolymer selected from the group consisting of melamine-formaldehyde prepolymers, urea-formaldehyde prepolymers, melamine-urea-formaldehyde prepolymers, melamine-thiourea-formal,dehyde prepolymers and melamine-thiourea-urea-formaldehyde prepolymers or a mixed prepolymer containing a melamine-formaldehyde prepolymer and a thiourea-formaldehyde prepolymer into polycondensation in the presence of both a water-soluble cat ionic urea resin and an anionic surfactant.
The material for the membrane of the micro capsule according to the present invention comprises an aminoplast prepared by polycondensa-tion in the presence of a modifier.
The micro capsule formed of the thus treated aminoplast is superior in solvent-resistance and free-flowing property to the micro capsule formed of the aminoplast which has not been treated, and in the same time, the micro capsule formed of the thus treated aminoplast exhibits an excellent pressure-responsive-news.
As the modifier used for the above-mentioned object, a finlike compound such as phenol, resorcinol, catcall, hydroquinone, crossly, Tylenol and saligenin and a polyalkylene-polyamide compound such as hexamethylenetetramine and triethylene thiamine may be exemplified.
In order to form the micro capsules according to the present invention, minute liquid particles of the component(s) :

Jo of the adhesive agent, which is (are) to be encapsulated are dispersed in an aqueous liquid in which the aminoplast prepolymer, the water-soluble cat ionic urea resin and anionic surfactant have been dissolved, and in the -thus prepared aqueous suspension, an cold catalyst, for instance, a carboxylic acid of a low mole-cuter weight such as formic acid, acetic acid and citric acid, an inorganic acid such as hydrochloric acid, nitric acid and phosphoric acid or a salt of which the aqueous solution exhibits an acidity or an easily hydrolyzable salt such as alunimum sulk fate, titanium oxychloride, magnesium chloride, ammonium chloride, ammonium nitrate, ammonium sulfate and ammonium acetate is added, and then, while causing a complex-coacervation by the water-soluble cat ionic urea resin and the anionic surfactant both of which have been dispersed in the aqueous dispersion of the aminoplast, the prepolymer and the water-soluble cat ionic urea resin are brought into polycondensation to form a hydropho-big membranes wall of a high molecular weight which completely covers each of the minute liquid particles of the components of the adhesive agent, which have been dispersed in the system, thus resulting in micro-encapsulation.
In the case where the above-mentioned modifier is added to the system during the polycondensation, the capsular membranes wall comprising the aminoplast treated with the modifier as has been explained is formed.

:

1~3SÇ~18 The amount of the modifier is 0.1 to 30% by weight, preferably 0.5 to 20% by weight to the prepolymer, the modifier is preferably added as an aqueous solution thereof at a con-cent ration of 0.02 to 5% by weight.

In this connection, the water-soluble cat ionic urea resin used for taking place the complex coacervation and for preparing the above-mentioned aminoplast is the substance obtained by introducing a cat ionic modifying group into a urea-formaldehyde resin, namely the product of polycondensation of, for instance, urea-formaldehyde prepolymer with polyalkylenepolyamine, guanidine, diaminoethanol, dicyandiamide, diethylaminoethanol and gainlier.
As the anionic surfactant, a substance such as those having a lipophilic group and an anionic - hydrophilic group in their molecule, for instance, salts of fatty acid, sulfate esters of higher alcohols and salts of alkylarylsulfonate may be mentioned, and for instance, sodium dodecylbenzenesulfonate is preferably used.
In addition, in the polycondensation for the formation of the micro capsules in the present invention, it is important that the two kinds of substances which are mutually different from each other concerning their sign of electric charge are coexistent with the prepolymer, the one of the substances being the water-soluble cat ionic urea resin and the other of the substances being the anionic surfactant. Owing to such an important situation, it is possible to obtain a stabilized aqueous dispersion containing micro capsules uniform in quality.

1~:3~6~8 Since the micro capsules of the present invention can be processed into a free-flowing powdery state after preparation by easily separating from the medium for dispersion used in the preparation thereof and drying thereof, the micro capsules are excellent in solvent resistance they are favorably suitable for forming the adhesive agent by uniformly dispersing in the other components of the adhesive agent.
The following is the concrete explanation of the adhesive agent containing the micro capsules according to the present invention (1) in the case where it is the type of chemical reaction and also (2) in the case where it is the type of solvent activation.
(1) Adhesive agent of the type of chemical reaction:
For the preparation of the adhesive agent of the type of chemical reaction, namely the adhesive agent comprising a resin, a monomer or oligomer for adhesion, an initiator of the reaction and a hardener, any one of these components may be encapsulated in the micro capsules and the micro capsules may be dispersed in, a mixture of the other components. As the component encapsulated in the micro capsules, the component smaller in amount, namely the initiator of the reaction or the hardener is generally selected. The kinds of the components encapsulated in the micro capsules may be not less than two, and not less than two kinds of the components may be encapsulated together or the respective components may be separately encapsulated.

123~

As the resin for adhesion, poly(acrylic acid), polymath-acrylic acid), epoxy resin, polyester, polyamide, polyurethane copolymer of urethane and lower alkyd acrylate or lower alkyd methacrylate, copolymer of dicarboxylic acid, dill and lower alkyd acrylate or lower alkyd methacrylate, epoxidized poly(lower alkyd acrylate), epoxidized poly(lower alkyd methacrylate), low-molecular silicone resin, natural rubber, neoprene rubber, polyvinyl acetate) and polystyrene may be mentioned. The micro capsules containing the necessary initiator for the reaction or the necessary hardener are dispersed in at least one resin selected from the above-mentioned resin and their monomers or oligomers for adhesion or in a solution prepared by dissolving thereof in an organic solvent.
As the initiator of the reaction, dibutyl-tin dilaurate, stuns caprylate or a solution of an organic peroxide such as y/
be l peroxide and dibutyl peroxide in an organic solvent may be mentioned, and as the hardener, N,N-dimethylaniline, N,N-dimethyl-Teledyne and the like may be mentioned.
In the case of utilizing the adhesive agent containing micro capsules of the type of chemical reaction, it is painted on one of the surfaces of a body, which is to be adhered and then the other body to be adhered to the first body is piled onto the first body so as to pinch the thus painted surface of the first body and then a pressure is applied onto the thus piled bodies from the side of the second body.
Then the micro capsules are easily broken to allow the free contact of the content of the micro capsules with the other SLY

components painted on the surface of the first body thereby the hardening is proceeded to obtain a strong adhesion of the two bodies. The adhesive agent containing micro capsules of the type of chemical reaction can b applied -to any surface by one ox several means such as to spraying, brushing, etc.
(2) Adhesive agent of the type of solvent activation:
For the preparation of the adhesive agent of the type of solvent activation, the micro capsules containing an organic solvent activating the resin which constitutes the adhesive membrane may be dispersed in the resin solution which constitutes the adhesive membrane.
As the organic solvent possibly encapsulated, almost all the generally used solvents are suitable for use, and hexane, Hutton, Bunsen, Tulane, zillion, carbon tetrachloride, trichloroethylene and tetrachloroethylene may be mentioned.
As the resin activated by the solvent, neoprene rubber, bottle rubber, styrene-butadiene rubber, natural rubber, polyp styrenes polyvinyl acetate), methyl cellulose, ethyl cellulose polyvinyl chloride), copolymer of ethylene and vinyl acetate, acrylic resin, methacrylic resin, polyamide, copolymer of vinyl acetate and lower alkyd acrylate may be mentioned.
The adhesive agent of the type of solvent activation according to the present invention comprising the above-mentioned micro capsules containing the solvent as the core substance dispersed in the resin solution which is to constitute the adhesive membrane and the resin. On the occasion of applying the ~3~i~18 adhesive agent of the type of solvent activation, the adhesive agent is painted on the surface to be adhered of one of the two bodies to be adhered, and after drying the thus painted adhesive agent, the body thus having a painted surface is placed on to the other of the two bodies to be adhered while applying a pros-sure onto the first body, thereby the micro capsules being broken by the pressure to allow the solvent freely activate the component of the resin in the painted surface resulting in a good adhesion.

Also the adhesive agent containing microcapsu~es of the type of solvent activation can be applied by spraying, brushing etc. onto the surface of a body, which is to be adhered to other body.
Since the micro capsule used in the present invention can be easily broken by applying a pressure of lower than 10 kg/cm2, the above mentioned adhesion of two bodies by lamination and pressing is easily carried out.
Accordingly, the adhesive agent containing micro capsules according to the present invention has a merit of utilizing in a broad field of adhering.
The present invention will be more precisely explained while referring to Examples as follows.
However, the present invention is not restricted to Examples under-mentioned. From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and without departing 1~:36618 from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.
EXAMPLE 1:
1-1: Preparation of two prepolymers After adjusting the pi of 162 g of aqueous 37 solution of formaldehyde (hereinafter referred to as formal in) by the addition of aqueous 2 % solution of sodium hydroxide to 9.0, it was mixed with 63 g of mailmen, and the mixture was brought into reaction while stirring the mixture at 70~. Just after confirming the complete dissolution of mailmen in the reaction mixture, 225 g of water were added to the reaction mixture, and the mixture was stirred for 3 mix to obtain an aqueous solution of a prepolymer of melamine-formaldehyde resin hereinafter referred to as M4F pro-polymer, M4F meaning that the molar ratio of mailmen to formalde-Hyde is I in the prepolymer).
Separately, after adjusting the pi of 146 g of formal in by the addition of triethanol amine to 8.5, it was mixed with 60 g of urea, and the mixture was brought into reaction for 1 hour at 70C to prepare an aqueous solution of a prepolymer of urea-formaldehyde resin hereinafter referred to as U 1.8 F prepolymer).
1-2: Preparation of a cat ionic urea resin After adjusting the pi of a mixture prepared by mixing 162 g of formal in and 60 g of urea and stirring the mixture to 8.8 by the addition of triethanolamine, the mixture was brought into reaction for 30 mix while stirring the mixture at 70C. Into 40 g .

1~3S6~8 of the reaction mixture, 24 g of water and 3 g of tetraethylene-pent amine were added, and the pi of the mixture was adjusted to 3.
by the addition of aqueous 15 % hydrochloric acid solution while stirring the mixture at 70C, and the reaction was carried out for 1 hour. Since the pi of the reaction mixture was reduced with the progress of the reaction, aqueous 10% solution of sodium hydroxide was added to the reaction mixture to adjust the pi thereof to 3.0, and the reaction was continued at a reduced temperature of 55C. At the time when the viscosity of the reaction mixture became 200 cups, the reaction mixture was neutralized with the addition ox aqueous 10% solution of sodium hydroxide and 400 g of water were added to the neutralized mixture to obtain an aqueous solution of the water-soluble cat ionic urea resin.
1-3: Microcapsulation A mixture consisting of 100 g of M4F prepolymer (refer to 1~1), 50 g of U 1.8 F prepolymer (refer to 1-1), 158 g of the aqueous solution of the water-soluble cat ionic urea resin (refer to 1-2), 62 g of water and l g of triethanolamine was adjusted to pi of 5.2 by the addition of aqueous 10% solution of citric acid, and by admixing the mixture with 3 g of aqueous 10% solution of NEPAL (sodium dodecylbenzenesul~onate, made by KETTLES Coo Japan) a solution named as A-liquid was obtained.
Into the thus prepared A-liquid, 200 ml of zillion were dispersed so tout the mean diameter of -the dispersed particles 1~36611 8 of zillion is 30 to 50 micrometers. The thus obtained aqueous dispersion was brought into reaction for one hour while gently stirring the dispersion and maintaining the dispersion at a temperature of 30C and adding aqueous 10% solution of citric acid to -the dispersion to adjust the pi of the dispersion at 3.6. After the lapse of further one hour, aqueous 10% solution of citric acid was added to the reaction mixture to adjust the pi thereof to 3.0, and then 20 ml of aqueous 10% solution of resorcinol were added to the mixture. The microcapsulation was completed after the further continued stirring for 18 hours.
After collecting the thus formed micro capsules, the capsules were washed with water and dried in an air-drier at 35C to be powdery micro capsules of the mean diameter of 30 to 50 micrometers.
I Preparation of an adhesive agent being the type ,. .
of solvent activation as the final product:
To a solution prepared by dissolving 100 parts by weigh-t of masticated neoprene rubber in 500 parts by weight of Tulane, one part by weight of a phenol resin and one part by weight of a Cameron resin were dissolved, and after adding 30 parts by weight of the micro capsules prepared in (1-3) to the thus prepared mixture, the whole mixture was uniformly mixed to obtain the adhesive agent containing the micro capsules.
EXAMPLES 2 to 9:
In the same procedures as in Example 1 except for using each prepolymer for membranes wall-formation and each modifier show in Tale 1 instep of those used in Example 1, 123~618 eight kinds of the adhesive agents according to the present invention were obtained.

1;~;3~i6~8 o _ ---- E

a) a o o o o o o o o o MU LO Us Us Lo I I Lo a o us a) o o o o o o o o o O a U o o o o o o o o o O I I I us Err Jo Jo __ _ o so O o o o o o o o Us o 0 or o _ _ _ Al _ o I l l o o o o o I a) o o Jo I O
a) o o t) o o h h S I h 51 I I) a h Q
s, s, 0 o o o o o 0 a) o a) s, o Jo aye us us us us us ,J~ I us I
I ,1 O a) a) a) Jo a) Allah h a) 0 o t) I I .'1.~1.~1.~1 I ,~~) t) Us I I
I I It ., or O O owe o o o o o o o o o _, o E Jo Jo Jo Jo Jo Jo Jo Jo 3 owe ox I Jo Jo o o o . . . . . . . . .
r) .,~ o Lo us Queue) Jo Jo o Jo .. Jo 3. E o _ _ ô _ _ o LO co I I`
I o o .~.~ o I_ *
o o o I_ I_ I o Jo o kiwi Jo Jo Jo .
o o o I_ _ Jo .~.~ _ _ _, b' I I
. I * 00~ *
. . Jo Jo (I
a Jo Jo I *
0 I) I En I I .
I . co ~-~ 1:'1 to I 1:4 I I I Jo I
'I or or En En Jo O
Pi _ _ ..
0aJ~
I O Jo I or us ED It CO I
W I O
1. l l I I I

3~i18 The respective prepolymers specified in Table 1 were prepared as follows:
Preparation ox the prepolymers *1: Tug 1.8 F used in Example 4 After adjusting the pi of 146 g of formal in to 8.5 by the addition or triethanolamine, the former was mixed with 76 g of Thor, and the mixture was brought into reaction for one hour at 70C to obtain an aqueous solution of the prepolymer of Tug 1.8 F (one mow of Thor: 1.8 mows of formaldehyde) *2:_ MTu4F used in Example 7 After adjusting the pi of 324 g of formal in to 9.0 by the addition of aqueous 2% solution of sodium hydroxide, the former was mixed with 63 g ox mailmen and 38 g of Thor, and the mixture was brought into reaction at 70C, and just after confirming the complete dissolving of mailmen and Thor into the reaction mixture, 425 g of water were added to the reaction mixture, and the resultant liquid was cooled to room temperature as it was.
*3. MTuU5F used in Example 8 After adjusting the pi of 405 g of formal in to 8.5 by the addition of triethanolamine, the former was mixed with 42 g of mailmen, 25 g of Thor and 20 g of urea, and the mixture was brought into reaction at 70C for one hour, and the product was cooled to room temperature.

3~i18 *4: MUFF used in Example 9 After adjusting the pi of 324 g of formal in to 8.5 by the addition of triethanolamine, the former was mixed with 63 g of mailmen and 30 g of urea, and the mixture was brought into reaction for 30 mix at kiwi After adding 225 g of water to the reaction mixture, the mixture was cooled to room temperature.
TEST EXAMPLE 1:
Each of the adhesive agents respectively prepared in Examples 1 to 9 was painted on a plate of posy (vinyl chloride) of 0.5 Mooney thickness at a rate of 6 g of the adhesive agent/m2 of the plate, and by drying the thus painted plate for 2 hours at 40C, a painted surface without stickiness was obtained.
; Then, another plate of posy (vinyl chloride) of 0.5 mm in thickness was piled onto the painted surface of the plate to have a laminate having two layers of posy (vinyl chloride) intervened by a layer of the adhesive agent, and the laminate was passed between the two pitch-rolls of a rolling pressure adjusted to 10 or 200 kg/cm2 to obtain an adhered body.
After leaving the adhered body as it was in an ordinary room for 24 hours, the adhesion between the two plates was tested.
The results are shown in Table 2 wherein the test results on the adhered body prepared by the adhesive agents prepared in the following Comparative Examples 1 to 5 are also shown for comparison.

1~3~i618 Table 2 Adhesion of the two plates adhere Adhesive agent under a pressure of prepared in _ 10 kg/cm 200 kg/cm I I
Example 1 good good Example 2 good good Example 3 good good Example 4 good good Example 5 good good Example 6 good good Example 7 good good Example 8 good good Example 9 good good _ Comparative Example 1 poor good Comparative Example 2 poor poor Comparative Example 3 poor poor Comparative Example 4 poor poor Comparative Example 5 poor poor I:

123~6~8 Note to Table 2 In Table 2, adhesion good means that the two plates were so firmly adhered together that any owe ox the two plates could not be moved in regard to the other of them by hands, and on the other hand, adhesion poor means that one of the two plates could be separated easily from the other by hands or the two plates were not adhered together.
COMPARATIVE EXAMPLE 1:
. __ By the same procedures as in Example 1 except for dispensing the addition of resorcinol as the modifier, an adhesive agent containing micro capsules was obtained.
COMPARATIVE EXAMPLES 2 to 4:
While using 100 g of M4F prepolymer prepared by the same procedures as in Example 1(1-1) and 50 g of U 1.8 F pro-polymer also prepared by the same procedures as in Example 1(1-1), however, using one of the third components shown in Table 3 instead of the water-soluble cat ionic urea resin and NEPAL
in Example 1, thereby obtaining a liquid corresponding to A-liquid in Example 1, 176 g of zillion were dispersed in the liquid under the same conditions as in Example 1. In the case where the pi of the thus formed aqueous dispersion became lower than 5.0, the pi of the liquid corresponding to A-liquid was adjusted to

5.0 by the addition of aqueous solution of sodium hydroxide.
The aqueous dispersions brought into reaction under the same conditions and according to the same procedures as in Example 1, however, without adding the aqueous 10 %

::

lZ36618 solution of resorcinol to obtain an aqueous dispersion of micro-capsules. After collecting the micro capsules and washing thereof with water, the washed micro capsules were air-dried.
By using the thus prepared micro capsules, an adhesive agent containing the micro capsules was obtained in the same procedures as in Example 1.

Table 3: Substance used as the third component ___ instead of water-soluble cat ionic urea resin and NEPAL
. .

n Comparatlv Sup e eddy I- the ire component 2 loathing used . . _ Jo . _._ SCRIPPS 520 (copolymer of styrenes and 3 malefic android, made by Monsanto Co.) as an aqueous 5% solution thereof: 75 g .. __ _ . _. .-- - ------- ---a reactive surfactant (disclosed in Japanese . 4 Patent Application Laying Open No. 46-7313 _ (197~ 20 g .
::
COMPARATIVE EXAMPLE 5:

: After dispersing 176 g of zillion in 275 g of an aqueous 10%~ by weight solution of gelatin at 50C as particles of 30 to : 50 micrometers in the mean diameter thereof, aqueous 10% solution I:
::

lZ;~i618 of gum Arabic and 450 ml of water were added thereto while gently stirring thereof, and after adjusting the pi of the thus formed mixture to 4.4 by the addition of aqueous 10% solution of acetic acid and leaving the mixture as it was for 10 mint the mixture was cooled to 5C and 36.5 ml of aqueous 25% solution of glutaric alluded was added thereto, and the mixture was stirred for one hour. After heating the mixture again to 50C
and continuing the stirring for 30 mint the mixture was cooled to room temperature to obtain a slurry of micro capsules. By using the dried, powdery micro capsules obtained by spray-drying the slurry of micro capsules, an adhesive agent containing the micro capsules was prepared in the same procedures as in Example 1.
It was found by examining the respective adhesive agents prepared in Comparative Examples 2 to 5 that the organic solvent originally encapsulated in the micro capsules had been evaporated off completely from the micro capsules without leaving anything.
EXAMPLE 10:
By the same procedures as in Example 1 except for using 176 g of a 5% solution of triallyl sonority in zillion or 176 g of a 5% solution of tertiary bottle perbenzoate in deathly phthalate instead of 176 g of zillion in Example 1, two kinds of the powdery micro capsules were prepared.

Separately, an adhesive agent was prepared by adding 0.5 part by weight of peroxide and 10 parts by weight of methyl Matthew yule into a solution prepared by dissolving 0 I. `

isle parts by weight of a tripolymer of ethylene, propylene and lo hexadiene into 360 parts by weight of Tulane and bringing the mixture into reaction for 5 hours at 80C.
An adhesive agent of the type of chemical reaction was prepared by blending 100 parts by weight of the thus obtained in-polymer and 6.5 parts by weight of the powdery micro capsules pro-pared by using triallyl sonority and 4.0 parts by weight of the powdery micro capsules prepared by using Perbutyl Z. By painting the thus prepared adhesive agent on the two respective Lyon plates and laminating them with their painted surfaces together and pressing the thus laminated body under a pressure of 10 kg/cm2 at 50C, a favorably laminated and adhered body was obtained.
In addition, the thus prepared adhesive agent containing the two kinds of the micro capsules retained the original adhesion even after one month of preservation EXAMPLE
By the same procedures as in Example 2 except for using 224 g of deathly phthalate containing 56 by weight of peroxide instead of 176 g of zillion in Example 2, a kind of micro capsules was prepared.
Separately, a mixed solution was prepared by dissolving 7 parts by weight of poly(methyl methacrylate) in a mixed solvent consisting of 150 parts by weight of bottle acetate, 120 parts by weight of ethyl acetate and 30 parts by weight of methyl isobutyl kitten, and further adding 40 parts by weight of methyl methacrylate and loo part by weight of N,N-dimethyl-Teledyne to the thus formed solution.

~Z31j618 By admixing the thus prepared mixed solution with

6.5 parts by weight of the micro capsules prepared as above, an adhesive agent of the type of chemical reaction, was obtained.
After spraying the adhesive agent onto a soft steel plate and evaporating the solvent, another soft steel plate was placed on the thus painted surface of the former soft steel plate, and by applying a pressure of 10 kg/cm2 onto the thus laminated soft steel plates, a laminated and adhered body of soft steel plate was obtained while breaking the micro capsules, and the body showed a strong adhesion between the components after 10 min.
COMPARATIVE EXAMPLE 6:
,...
In the same procedure of microcapsulation.in Compare-live Example 5 except for using 224 y of deathly phthalate containing 5% by weight of be}. peroxide instead of 176 g of zillion ion Comparative Example 5, a kind of rnicrocapsules was obtained.
After preparing an adhesive agent by admixing 6.5 parts by weight of the thus prepared micro capsules with the same mixed solution as in Example 11, the thus prepared adhesive agent was I sprayed on a soft steel plate and evaporated the solvent. By plea-in another soft steel plate on the thus painted and dried surface !
of the former soft steel plate and applying a pressure of 10 kg/cm onto the thus laminated soft steel plates as in Example 11~ a laminate body was obtained, however, the adhesion between the two plates was not satisfactory. No improvement of adhesion was :

_ I - ` I

'1~3~L8 obtained in another test of soft steel plate lamination even by applying a pressure of 200 kg/cm2 while using the same adhesive agent.
EXAMPLE 12:
By the same procedures for preparing the micro capsules as in Example 6 except for using 180 g of a mixture of 100 parts by weight of EON 828 (an epoxy-resin, made by duo Pont Co.) and 10 parts by weight of zillion instead of 176 g of zillion in Example 6, a slurry of micro capsules was prepared.
After collecting the micro capsules from the slurry, the micro capsules were washed with water and dried to be freely-flowing powdery micro capsules.
By admixing a solution prepared by dissolving 100 parts by weight of N-methoxy-(methylated nylon), so-called nylon 8, into 200 parts by weight of methanol with 20 parts by weight of the thus prepared free-flowing powdery micro capsules, an ache-size agent containing micro capsules was prepared.
After painting the thus prepared adhesive agent on a single Lyon plate, another single Lyon plate was placed thereon and by applying a pressure of 10 kg/cm2 onto the thus laminated body at 70C, a strongly adhered body of laminated Lyon plates was obtained.
Even after leaving the thus laminated body for one week at a temperature of 70C and a relative humidity of 75 %, no noticeable deterioration of adhesion was found between the adhered plot ` ' ~3~L8 In addition, the thus prepared adhesive agent count awn-in the micro capsules could be preserved in a stable state without gellifying even after one month.

Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. An adhesive agent containing microcapsules, comprising;
(a) said microcapsules consisting essentially of a core substance of at least one of the components of said adhesive agent and, as a material for the membrane of said microcapsule, an aminoplast preliminarily treated by a modifier selected from the group consisting of resorcinol, catechol, hydroquinone, cresol, xylenol, saligenin, hexa-methylenetetramine and triethylenetetramine, and (b) a medium consisting of the other components of said adhesive agent;
said aminoplast being formed by polycondensation of a water-soluble cationic urea resin and at least one pre-polymer selected from the group consisting of melamine-formaldehyde prepolymers, urea-formaldehyde prepolymers, melamine-urea-formaldehyde prepolymers, melamine-thiourea-formaldehyde prepolymers and melamine-thiourea-urea-form-aldehyde prepolymers, or at least one mixed prepolymer con-taining a melamine-formaldehyde prepolymer and a thiourea-formaldehyde prepolymer in the presence of an anionic sur-factant selected from the group consisting of salts of fatty acid, sulfate esters of higher alcohols and salts of alkyl-arylsulfonic acid and an acidic catalyst while causing a complex-coacervation between the water-soluble cationic urea resin and the anionic surfactant, said microcapsules being dispersed in said medium and said adhesive agent being selected from the group consisting of an adhesive agent of the chemical reaction type and an adhesive agent of the solvent activation type.

2. An adhesive agent containing microcapsules according to Claim 1, wherein said microcapsules encapsu-lating a reaction initiator and/or a hardener as said core substance have been dispersed in a mixture of the other components of said adhesive agent.

3. An adhesive agent containing microcapsules according to Claim 2, wherein said reaction initiator is dibutyltin dilaurate, stannous caprylate, benzyl peroxide or dibutyl peroxide.

4. An adhesive agent containing microcapsules according to Claim 2, wherein said hardener is N,N-dimethyl-aniline or N,N-dimethyltoluidine.

5. An adhesive agent containing microcapsules, of the type of solvent activation according to Claim 1, wherein said microcapsules encapsulating a solvent as said core substance which activates the resin constructing the adhe-sive membrane, have been dispersed in the resin solution which constructs said adhesive membrane.

6. An adhesive agent containing microcapsules according to Claim 5, wherein said solvent is selected from the group consisting of benzene, toluene, xylene, hexane, heptane, carbon tetrachloride, trichloroethylene and tetra-chloroethylene.

7. A process for preparing an adhesive agent con-taining microcapsules, of the type of chemical reaction or the type of solvent activation, comprising;
dispersing minute liquid particles of at least one of the components of said adhesive agent in an aqueous dis-persion of at least one prepolymer selected from the group consisting of melamine-formaldehyde prepolymers, urea-form-aldehyde prepolymers, melamine-urea-formaldehyde prepolymers, melamine-thiourea-formaldehyde prepolymers and melamine-thiourea-urea-formaldehyde prepolymers, or at least one mixed prepolymer containing a melamine-formaldehyde pre-polymer and a thiourea-formaldehyde prepolymer, and a water-soluble cationic urea resin, polycondensing said prepolymer and said water-soluble cationic urea resin in the presence of an anionic surfactant selected from the group consisting of salts of fatty acid, sulfate esters of higher alcohols and salts of alkylarylsulfonic acid and an acidic catalyst while causing a complex-coacervation between the water-soluble cationic urea resin and the anionic surfactant, adding a modifier selected from the group consist-ing of resorcinol, catechol, hydroquinone, cresol, xylenol, saligenin, hexamethylenetetramine and triethylenetetramine to said aqueous dispersion during said polycondensation, thereby forming said microcapsules encapsulating said at least one of said components within the membrane consisting essentially of said aminoplast modified by said modifier, collecting and drying the thus formed micro-capsules, and dispersing said microcapsules in the other com-ponents constructing said adhesive agent containing micro-capsules.

8. A process according to Claim 7, comprising adding 0.1 to 30% by weight, preferably 0.5 to 20% by weight of said modifier to said prepolymer of said components for forming said aminoplast.

9. A process according to Claim 8, comprising adding said modifier as an aqueous solution containing 0.02 to 5% by weight thereof.

10. A process according to Claim 7, comprising dispersing said microcapsules encapsulating said reaction initiator and/or said hardener in a mixture of the other components of said adhesive agent containing microcapsules.

11. A process according to Claim 10, wherein said reaction initiator is dibutyltin dilaurate, stannous capryl-ate, benzyl peroxide or dibutyl peroxide.

12. A process according to Claim 10, wherein said hardener is N,N-dimethylaniline or N,N-dimethyltoluidine.

13. A process for preparing an adhesive agent containing microcapsules, of the solvent activation type according to Claim 7, comprising dispersing said micro-capsules encapsulating a solvent as a core substance acti-vating the resin which is to construct the adhesive membrane in the resin solution which is to construct said adhesive membrane.

14. A process for preparing an adhesive agent containing microcapsules according to Claim 5, wherein said solvent for activating said resin is selected from the group consisting of benzene, toluene, xylene, hexane, heptane, carbon tetrachloride, trichloroethylene and tetrachloro-ethylene.

15. A process for preparing an adhesive agent containing microcapsules according to Claim 7, wherein said acid catalyst is one compound selected from the group con-sisting of formic acid, acetic acid, citric acid, hydro-chloric acid, nitric acid, phosphoric acid, aluminum sulfate, titanium oxychloride, magnesium chloride, ammonium chloride, ammonium nitrate, ammonium sulfate and ammonium acetate.

16. A process for preparing an adhesive agent containing microcapsules according to Claim 7, wherein said water-soluble cationic urea resin is a resin obtained by bringing a urea-formaldehyde prepolymer into polycondensation with a polyalkylenepolyamine, guanidine, diaminoethanol, dicyandiamide, diethylaminoethanol or guanylurea.

17. A process according to Claim 7, wherein said anionic surfactant is salts of fatty acid, sulfate esters of higher alcohols or salts of alkylarylsulfonates.