JP5360378B2 - Method for producing latent curing agent and method for producing adhesive - Google Patents

Description

  The present invention relates to a method for producing an adhesive and a method for producing a latent curing agent used in the adhesive.

Generally, a curing agent that cures a thermosetting resin is added to the adhesive, and a latent curing agent in which a curing agent is encapsulated is conventionally used in order to improve the storage stability of the adhesive.
As a latent curing agent, for example, a polyurea resin particle in which a curing agent such as an aluminum chelate is held is known (see, for example, Patent Document 3).

However, since the polyurea resin particles have a high affinity with the organic solvent in the adhesive and the low-molecular thermosetting resin, they easily penetrate into the particles. There were limitations on the type and amount of solvent and the type of thermosetting resin.
In addition, since the polyurea resin particles have a low mechanical strength, the curing agent is easily released when the adhesive is cured, but there is also a problem that a large amount of the curing agent cannot be retained.

JP-A-6-238158 JP-A-8-131816 International Publication No. 2005/033173 Pamphlet

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a latent curing agent and an adhesive that are highly reactive when curing the adhesive and have excellent storage stability. .

In order to solve the above problems, the present invention cures the resin by contact reaction between the contained main curing agent and the auxiliary curing agent in the resin when heated while dispersed in the resin. A method for producing a latent curing agent to produce an oil phase liquid containing a hydrolyzable main curing agent, a water-reactive monomer that polymerizes by reacting with water, and a lipophilic monomer that is polymerized by heating. The oil phase liquid is dispersed in an aqueous phase liquid containing water as a main component to prepare a suspension in which droplets of the oil phase liquid are dispersed in the aqueous phase liquid. Heating, polymerizing the water-reactive monomer, polymerizing the lipophilic monomer, and a first latent resin containing the main curing agent in a resin particle comprising a water-reactive monomer polymer and a lipophilic monomer polymer. After creating the adhesive curing agent, the first latent curing agent is added to the hydrolyzable A method for producing a latent curing agent in which the first organic solvent to create a second latent curing agent is immersed in an organic cleaning liquid containing the dissolved curing agent.
This invention is a manufacturing method of a latent hardening | curing agent, Comprising: Creation of the said oil-phase liquid is a manufacturing method of the latent hardening agent which uses aluminum chelate as said main hardening | curing agent.
This invention is a manufacturing method of a latent hardening | curing agent, Comprising: Preparation of the said oil-phase liquid is a manufacturing method of the latent hardening agent which uses isocyanate as the said water-reactive monomer.
This invention is a manufacturing method of a latent hardening | curing agent, Comprising: Creation of the said oil-phase liquid is a manufacturing method of the latent hardening | curing agent which contains the said aluminum chelate more than the weight of the said isocyanate.
The present invention is a method for producing a latent curing agent, and the production of the oil phase liquid is a method for producing a latent curing agent using a vinyl monomer and / or an acrylic monomer as the lipophilic monomer. is there.
This invention is a manufacturing method of a latent hardening | curing agent, Comprising: Creation of the said oil-phase liquid is a manufacturing method of a latent hardening | curing agent which uses divinylbenzene as the said vinyl monomer.
The present invention is a method for producing a latent curing agent, wherein the washing of the resin particles is a method for producing a latent curing agent in which the organic cleaning liquid contains one or both of toluene and an organic carbonyl compound. .
This invention is a manufacturing method of a latent hardening | curing agent, Comprising: It is a manufacturing method of the latent hardening | curing agent which uses any one or both of ethyl acetate and methyl ethyl ketone as said organic carbonyl compound.
The present invention is a method for producing an adhesive, the latent curing agent produced by the method for producing a latent curing agent, a second organic solvent for dissolving the hydrolyzable main curing agent, and a heat It is the manufacturing method of the adhesive agent disperse | distributed to the binder containing curable resin and the said auxiliary | assistant hardening | curing agent.
The present invention is a method for producing an adhesive, wherein an aluminum chelate is used as the main curing agent, an epoxy resin is used as the thermosetting resin, and a silane coupling agent is used as the auxiliary curing agent. is there.
The present invention is a method for producing an adhesive film, wherein after forming the coating layer of the adhesive produced by the method for producing an adhesive, the second organic solvent is removed from the coating layer, and the coating layer is formed. This is a method for producing an adhesive film to be formed into a film.

  The present invention is configured as described above, and the resin particles contain a polymer of a lipophilic monomer, so that the mechanical strength is higher than the case where the resin particle is composed only of a water-reactive monomer polymer. Therefore, a large amount of the main curing agent can be held inside with a small amount of resin.

  For example, when DVB was added to the oil phase liquid, the content of the aluminum chelate could be increased by about 5 times compared to the case where DVB was not added. When the amount of the main curing agent held is large, the adhesive can be cured with a small amount of the latent curing agent, so that the amount of the latent curing agent added can be reduced.

  When an aluminum chelate is used as the main curing agent, if a silane coupling agent is used as the auxiliary curing agent, a cation is generated by the reaction between the aluminum chelate and the silane coupling agent, and the thermosetting resin is cationically polymerized by the cation. To do. In cationic polymerization, the curing reaction proceeds quickly at a low temperature. Therefore, when the main curing agent contained in the latent curing agent and the auxiliary curing agent contact with each other, the adhesive is cured at a low temperature in a short time.

  When isocyanate is used as the water-reactive monomer, the water-reactive monomer polymer is polyurea. When a heat-responsive resin such as polyurea is heated to a temperature higher than the glass transition temperature, hydrogen bonds are broken and molecular chains are loosened. Therefore, when the resin particles contain polyurea, when the adhesive is heated, the main curing agent in the particles quickly reacts with the auxiliary curing agent outside the particles.

  When the lipophilic monomer is a radical polymerizable monomer such as a vinyl monomer or an acrylic monomer, a radical polymerization initiator that releases radicals by heating, for example, can be used as the polymerization initiator. The radical polymerization initiator releases radicals by heating, and the lipophilic monomer is radically polymerized by the radicals.

When the surface or the whole of the resin particles is not sufficiently cured, when the first latent curing agent is added to the adhesive as it is, the portion where the second organic solvent in the adhesive is not sufficiently cured of the resin particles And the main curing agent is released into the adhesive even at room temperature.
Since the main curing agent is not released further into the organic solvent from the latent curing agent (second latent curing agent) after washing, the room temperature storage stability when added to the adhesive is high.

  The type of the first organic solvent used in the organic cleaning liquid is not particularly limited. For example, if it is cleaned with the same second organic solvent used for the adhesive, it can be dissolved in the second organic solvent at least in the adhesive. Things can be removed beforehand.

  The second organic solvent is preferably an organic solvent that has high solubility of the adhesive-containing resin (for example, thermosetting resin, thermoplastic resin, etc.) and can be dried at a low temperature. And organic carbon compounds such as MEK and toluene.

When the adhesive is heated in order to remove the organic solvent in the manufacturing process of the adhesive film, the film can be formed without curing the adhesive if the heating temperature is set to be equal to or lower than the curing start temperature of the adhesive. .
The curing temperature can be adjusted in a low temperature region by changing the blending amount and type of the lipophilic monomer and the polymerization conditions. For example, when the adhesive obtained according to the present invention is dried by heating to form a film, if the curing start temperature is set higher than the heating temperature for film formation, the thermosetting resin is formed without being polymerized. be able to.

  An adhesive having high storage stability and a high curing speed when used can be obtained. Compared to the conventional case, the amount of solvent added during the production of the curing agent can be reduced, which is effective in reducing the environmental burden. Since the particle size of the resin particles can be controlled in units of several μm, it can be used as an adhesive for fine pitch wiring connection. Since the first and second latent curing agents are solid powders, it is possible to design an adhesive composition that meets the needs. By adding the lipophilic monomer, characteristics other than the water-reactive monomer polymer can be imparted to the latent curing agent.

It is a DSC chart of the adhesive manufactured by this invention. It is an electron micrograph of the latent hardener manufactured by this invention. It is an electron micrograph (enlargement) of the latent hardening agent manufactured by the present invention. It is an electron micrograph of the latent hardening agent of a comparative example. It is a DSC chart when the compounding quantity of a lipophilic monomer is changed. It is a DSC chart when the kind of lipophilic monomer is changed. It is a DSC chart (DVB substitution rate 30%) of the adhesive agent which added the 2nd latent hardener. It is the DSC chart (DVB substitution rate 40%) of the adhesive agent which added the 2nd latent hardener. It is a DSC chart of a reference example. It is a TEM photograph of the latent hardening agent manufactured by the present invention. It is a DSC chart at the time of changing the washing | cleaning time of a latent hardening | curing agent. It is a DSC chart at the time of changing DVB substitution rate.

The manufacturing method which manufactures the anisotropic conductive film of this invention is demonstrated.
If the organic solvent used in the organic cleaning liquid to be described later is the first organic solvent and the organic solvent capable of dissolving the thermosetting resin is the second organic solvent, the thermosetting resin is used in the production of the anisotropic conductive film. A latent curing agent (first or second latent curing agent) that cures the thermosetting resin as described later in the binder liquid in which the resin is dissolved in the second organic solvent and the conductive particles are dispersed. Disperse to create a liquid adhesive.

The latent curing agent contains a main curing agent inside the resin particles, and even if an auxiliary curing agent that reacts with the main curing agent to cure the thermosetting resin is added to the binder liquid, at room temperature. Since the main curing agent contained in the latent curing agent and the auxiliary curing agent do not contact with each other, the adhesive is not cured.
An adhesive is applied to the surface of the release film to form a coating layer, and then dried to remove the second organic solvent, whereby the coating layer becomes a film and an anisotropic conductive film is obtained.

  As described above, the adhesive is not cured, and the anisotropic conductive film is not cured at room temperature. However, when the adhesive or anisotropic conductive film is heated during use, the latent curing agent contains The thermosetting resin is polymerized by contact reaction between the curing agent and the auxiliary curing agent.

Next, the process for forming the latent curing agent will be described.
Add the hydrolyzable water-reactive monomer, the lipophilic monomer to be polymerized by heating, and the poorly water-soluble organic solvent to the main curing agent described above to create an oil phase liquid mainly composed of the main curing agent. .
An aqueous phase solution in which a dispersant and a surfactant are added to water is prepared, and the oil phase liquid is added to an aqueous phase liquid having an amount equal to or larger than the amount of the oil phase liquid to prepare a suspension, followed by stirring. .

  The main curing agent is a hydrolyzable substance. When the main curing agent is hydrolyzed, heat is generated and the oil phase liquid is gelled. However, the main curing agent is protected by the lipophilic monomer and the organic solvent in the oil phase liquid. Therefore, hydrolysis is suppressed, and the oil phase liquid does not gel and forms droplets that are uniformly dispersed in the aqueous phase liquid.

Since the water-reactive monomer is in contact with water on the surface of the droplet, the water-reactive monomer is hydrolyzed to produce an intermediate product, which reacts with the water-reactive monomer before hydrolysis. As a result, a polymer of water-reactive monomer is produced (interfacial polymerization reaction).
When the suspension is heated, the lipophilic monomer is polymerized, and the polymerization of the water-reactive monomer is promoted, and the droplets are cured while the main curing agent is held inside.

  At this time, when the heating temperature of the suspension is set to be equal to or higher than the boiling point of the organic solvent added to the oil phase liquid (for example, when ethyl acetate is used as the organic solvent, the heating temperature is lower than the boiling point of 77 ° C. of ethyl acetate). 80 ° C), the organic solvent is removed from the droplets by evaporation, and the main curing agent of the total weight or more of the polymer is retained in the resin particles composed of the polymer of the lipophilic monomer and the polymer of the water-reactive monomer. The first latent curing agent is obtained.

  When resin droplets are formed by curing droplets in the suspension, the particle size of the droplets cannot be reduced if the dispersibility of the oil phase liquid is poor. growing. As described above, in the present application, since it is uniformly dispersed in the aqueous phase liquid, the particle size of the resin particles of the first latent curing agent can be reduced to a few μm unit.

Distilled water is added to the aqueous phase solution (polymerization solution) containing the first latent curing agent and washed, and then the first latent curing agent particles are filtered from the polymerization solution.
When the first organic solvent that dissolves the hydrolyzable main curing agent is an organic cleaning solution, and the first latent curing agent that has been filtered off from the polymerization solution is immersed in the organic cleaning solution, it is not retained inside the resin particles, The main curing agent only attached to the surface and the degree of polymerization are low, and as a result, the portion of the main curing agent having a high solvent permeability is extracted into the organic solvent (organic cleaning liquid).

As described above, since the resin particles contain a large amount of the main curing agent, a large amount of the main curing agent is retained inside the resin particles even after washing with the organic cleaning liquid, and a second latent curing agent is obtained.
As described above, if the particle size of the resin particles of the first latent curing agent is reduced to a few μm unit, the particle size of the resin particles of the second latent curing agent is also reduced to a few μm unit.

<First latent curing agent>
Isocyanate (trade name “D-109”, manufactured by Mitsui Takeda Chemical Co., Ltd.), which is a water-reactive monomer, and divinylbenzene (Merck, Inc.), which is a lipophilic radically polymerizable monomer (lipophilic monomer). ) Total weight of 70 parts by weight (parts by weight), 350 parts by weight of the main curing agent, aluminum chelate (trade name “Aluminum Chelate D”, manufactured by Kawaken Fine Chemical Co., Ltd.), and organic solvent, ethyl acetate 70 parts by mass was mixed, and a radical polymerization initiator (trade name “Perroyl L” manufactured by Nippon Oil & Fats Co., Ltd.) was added at 1% by weight of the amount of divinylbenzene to prepare an oil phase liquid.

  In 800 parts by weight of distilled water, 4 parts by weight of polyvinyl alcohol (trade name “PVA205” manufactured by Kuraray Co., Ltd.) as a dispersant and a surfactant (trade name “Newrex R” manufactured by Nippon Oil & Fats Co., Ltd.) -T ") 0.05 parts by mass to prepare an aqueous phase liquid, and the suspension obtained by dispersing the oil phase liquid in the aqueous phase liquid is stirred while being heated to 80 ° C. A latent curing agent was obtained. The particle diameter of the resin particles of the first latent curing agent was set to 5 μm or less (average particle diameter in terms of volume is about 2.3 μm).

  90 parts by mass of an alicyclic epoxy resin (trade name “CEL2021P” manufactured by Daicel Chemical Industries, Ltd.) which is a thermosetting resin, and a silane coupling agent (Shin-Etsu Chemical Co., Ltd.) which is an auxiliary curing agent The adhesive agent of Example 1 was created by adding 2 parts by mass of the first latent curing agent before washing with an organic cleaning liquid to 12 parts by mass of “KBM5103”).

  Instead of the first latent curing agent, aluminum chelate was added directly to the adhesive to make the adhesive of Comparative Example 1, and the latent curing agent was made without adding divinylbenzene to the oil phase liquid. The latent curing agent was added to the adhesive instead of the first latent curing agent of Example 1 to prepare the adhesive of Comparative Example 2.

These three types of adhesives were subjected to DSC analysis (Differential scanning calorimetry). A DSC chart is shown in FIG. Note that symbols E ₁ , C ₁ , and C ₂ in FIG. 1 indicate DSC charts of Example 1 and Comparative Examples 1 and 2, respectively.

  The temperature at which the DSC chart rises was defined as the heat generation start temperature, the temperature at which the chart reached the peak was defined as the heat generation peak temperature, and the maximum intensity of the chart was defined as the heat generation peak intensity. “Exothermic start temperature”, “Exothermic peak temperature”, and “Exothermic peak intensity” are listed in Table 1 below together with the DVB substitution rate.

  The DVB substitution rate is a value obtained by dividing 100 by the value obtained by dividing the blending amount (weight) of DVB (divinylbenzene) by the sum of the blending amount of DVB and the blending amount of isocyanate. The exothermic start temperature is a temperature at which the polymerization reaction of the thermosetting resin starts, and the exothermic peak temperature is a temperature at which the polymerization reaction of the thermosetting resin reaches a peak.

  As can be seen from Table 1 and FIG. 1 above, both when the aluminum chelate was added directly and when the latent curing agent was prepared without adding DVB, the heat generation start temperature was room temperature, but DVB was added. In Example 1 where the latent curing agent was prepared, it was found that the heat generation start temperature was higher than room temperature and the storage stability was high. Moreover, the adhesive of Example 1 has a narrower peak width than Comparative Examples 1 and 2, and it can be seen that the curing of the adhesive proceeds in a short time.

  Next, the state of the resin particles of the first latent curing agent of Example 1 and the latent curing agent of Comparative Example 2 was observed. 2 and 3 are electron micrographs of the first latent curing agent of Example 1, and FIG. 4 is an electron micrograph of the latent curing agent of Comparative Example 2.

The first latent curing agent of Example 1 had no problem with the particle shape and the surface state of the particles, but the latent curing agent of Comparative Example 2 showed many irregularities on the particle surface.
The fact that there are many irregularities on the particle surface is not the surface of the particle formed by uniform interfacial polymerization, so it has an adverse effect on the storage stability at room temperature, so from this observation result also add lipophilic monomer to the oil phase liquid It can be seen that a latent curing agent having excellent storage stability at room temperature can be obtained.

<Amount of lipophilic monomer>
Except for changing the blending amount of DVB, a first latent curing agent having a DVB substitution rate of 20% and 40% was prepared under the same conditions as in Example 1, and these two types of first latent curing agents were prepared. The adhesives of Examples 2 and 3 were created under the same conditions as in Example 1.

DSC analysis was performed on the adhesives of Examples 2 and 3 and the adhesives of Example 1 and Comparative Example 2 above. A DSC chart is shown in FIG. Note that reference numerals E _{1 to} E ₃ and C ₂ in FIG.
3 and the DSC chart of Comparative Example 2 are shown. The “exothermic start temperature”, “exothermic peak temperature”, and “exothermic peak intensity” read from the DSC chart are shown in Table 2 below together with the DVB substitution rate.

  As the blending amount of DVB increases, both the heat generation start temperature and the heat generation peak temperature are shifted to a higher temperature side. In order to prepare a low-temperature curable adhesive having a heat generation peak temperature of 90 ° C. or lower, the DVB substitution rate is at least 50 It turns out that it is necessary to make it below%.

<Types of lipophilic monomers>
Instead of DVB, three types of first latent curing agents were prepared under the same conditions as in Example 1 except that three types of acrylic monomers were used, and these three types of first latent curing agents were used. Thus, adhesives of Examples 4 to 6 were obtained. In addition, the compounding quantity of the acrylic monomer was 30 mass parts with respect to 100 mass parts in total with isocyanate.

  As acrylic monomers, 1,6-HDDA (1,6-hexanediol diacrylate, trade name “A-HDN” manufactured by Shin-Nakamura Chemical Co., Ltd.) and A-TMPT (trimethylolpropane triacrylate) , Shin-Nakamura Chemical Co., Ltd. trade name) and A-TMMT (tetramethylol methane tetraacrylate, Shin-Nakamura Chemical Co., Ltd. trade name) were used.

DSC analysis was performed on these three types of adhesives, and the obtained DSC chart is shown in FIG. Incidentally, it shows the DSC chart of the respective code E ₄ to E ₆ in FIG. 6 Examples 4-6. “Exothermic start temperature”, “exothermic peak temperature”, and “exothermic peak intensity” read from the DSC chart are shown in Table 3 below together with the types of acrylic monomers.

  As apparent from Table 3 above, the heat generation start temperature was higher than room temperature, and the heat generation peak temperature was less than 90 ° C. From this result, it can be seen that even when an acrylic monomer is used instead of a vinyl monomer such as DVB as a lipophilic monomer, a latent curing agent having high room temperature storage stability and high adhesive curability can be obtained.

<Storage stability test>
Using the first latent curing agent prepared in Example 1 above, the adhesive composition of Examples 7 to 9 was prepared by changing the composition of the adhesive from Example 1. The composition of each adhesive is shown in Table 4 below.

  “CEL2021P” in Table 4 above is a trade name manufactured by Daicel Chemical Industries, Ltd., and is an alicyclic epoxy resin. “EP807” is a trade name manufactured by Japan Epoxy Resins Co., Ltd., and is a bisphenol F type epoxy resin. “KBM5103” is a trade name manufactured by Shin-Etsu Chemical Co., Ltd., and is a silane coupling agent.

  For the adhesives of Examples 7 to 9, using a vibrating viscometer (trade name “SV-10” manufactured by A & D Co., Ltd.), the increase in viscosity when stored at 30 ° C. was measured, The measurement results are shown in Table 4 above.

  As can be seen from Table 4 above, the adhesives of Examples 7 to 9 had little increase in viscosity until 5 hours and the adhesive did not cure, but the adhesives of Example 7 were cured in less than 10 hours. .

  The alicyclic epoxy resin has an initial viscosity as low as 252 cP / 25 ° C., and a resin with a low initial viscosity has a high permeability of the resin particle wall, like an organic solvent. Therefore, only an alicyclic epoxy resin is used as a thermosetting resin. In Example 7 used, it was estimated that the epoxy resin penetrated into the latent particles and the curing reaction of the adhesive proceeded even at 30 ° C.

  On the other hand, when a resin having a high initial viscosity, such as the above bisphenol F type epoxy resin (3000 to 4500 cP / 25 ° C.), is contained in the adhesive, the viscosity increase is slow. When blending more than the same amount of resin, it was confirmed that even in a low temperature adhesive having a curing start temperature of about 50 ° C. confirmed by DSC chart, even when stored for 48 hours, the increase in viscosity hardly progressed. .

<Cleaning test>
After washing the first latent curing agent (DVB rate 30%, 40%) prepared in Examples 1 and 3 with water, toluene, ethyl acetate, PGMAC (propylene glycol monomethyl ether acetate), MEK ( Methyl ethyl ketone) was washed by immersion for 4 hours under conditions of a liquid temperature of 30 ° C. and a particle concentration of 1% to prepare 8 types of second latent curing agents.

  86 parts by mass of alicyclic epoxy resin (trade name “CEL2021P” manufactured by Daicel Chemical Industries, Ltd.) and 6 parts by mass of silane coupling agent (trade name “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) The 8 types of second latent curing agents and the 2 types of first latent curing agents were each added in an amount of 8 parts by mass to prepare adhesives of Examples 10 to 19.

  Among Examples 10 to 19, Examples 10 to 14 are cases where the DVB substitution rate is 30%, and Examples 15 to 19 are cases where the DVB substitution rate is 40%. Examples 10 and 15 are cases where the first latent curing agent was used without washing. Examples 11 and 16 are cases where toluene is used, Examples 12 and 17 are ethyl acetate, Examples 13 and 18 are PGMAC, and Examples 14 and 19 are cases where MEK is used as an organic cleaning liquid.

  DSC analysis was performed on the adhesives of Examples 10 to 14 and the adhesives of Examples 15 to 19, respectively. The DSC chart of the adhesives of Examples 10 to 14 is shown in FIG. 7, and the DSC chart of the adhesives of Examples 15 to 19 is shown in FIG.

Reference numeral E ₁₀ to E ₁₄ in Figure 7 shows the DSC chart of the respective embodiments 10-14, it shows the DSC chart of the code E ₁₅ to E ₁₉ are examples 15 to 19 in FIG. “Exothermic start temperature”, “exothermic peak temperature” and “exothermic peak intensity” read from each DSC chart are shown in Tables 5 and 6 below.

As is apparent from FIGS. 7 and 8, the first and second latent curing agents produced according to the present invention both have a heat generation start temperature exceeding room temperature and have room temperature storage stability.
In particular, Examples 11 to 14 and 16 to 19 using the second latent curing agent after washing have high exothermic start temperature and exothermic peak temperature, and the exothermic peak width is narrow, which is lower than that before washing. It can be seen that the storability is high and the reactivity during curing is also high.

  Comparing the case where the DVB substitution rate is 30% and the case where it is 40%, Examples 11 to 14 in which the substitution rate is 30% have a heat generation start temperature higher than those in Examples 16 to 19 in which the substitution rate is 40%. Low, exothermic peak width is narrow, and reactivity during curing is high. This indicates that the lower the substitution rate of DVB, the more easily the main curing agent contained in the resin particles reacts with the auxiliary curing agent.

  In addition, when examining the types of organic cleaning liquids, when the DVB substitution rate was 30%, the exothermic peak intensity was particularly high when toluene and ethyl acetate were used. When the DVB substitution rate was 40%, MEK was used. The exothermic peak intensity was particularly high. The higher the exothermic peak intensity, the higher the reactivity at the time of curing the adhesive, and considering the reactivity, it can be seen that toluene, ethyl acetate and MEK are suitable as the organic cleaning liquid.

<Cleaning test: Reference example>
In order to compare with the present invention, the latent curing agent product prepared without adding a lipophilic monomer to the oil phase liquid, such as the latent curing agent described in JP-A-2006-70051, was implemented as described above. Washing was performed under the same conditions as in Examples 11-14.

  Using the latent curing agent before and after washing, the adhesives of Reference Examples 1 to 4 were prepared with the same formulation as in Examples 11 to 14, and DSC analysis was performed. The DSC chart of Reference Examples 1 to 4 is shown in FIG. 9, and “exotherm start temperature”, “exothermic peak temperature”, “exothermic peak intensity”, and “peak area” read from the DSC chart are the types of cleaning liquids. And listed in Table 7 below.

Reference Example 1 is an adhesive using a latent curing agent before washing, and Reference Examples 2 to 4 are adhesives using a latent curing agent washed with MEK, ethyl acetate, and toluene, respectively. code s ₁ ~s ₄ in 9 respectively show the DSC chart of the reference example 1-4.

  When the latent curing agent is prepared without including the lipophilic monomer in the oil phase liquid, the exothermic peak temperature of the latent curing agent before washing is originally as high as 100 ° C. or higher. Also in Reference Example 4 using toluene having the smallest intraparticle permeability as the organic cleaning liquid, the exothermic peak temperature is as high as 108 ° C. Further, in Reference Example 2 using MEK as the organic cleaning liquid, the exothermic chart was the broadest (wide).

  In contrast, as shown in Table 6 above, the adhesive produced according to the present invention has a narrow heat generation chart even when MEK is used as the organic cleaning liquid, and therefore has a higher thermal response than the reference example. It turns out that it hardens | cures in a short time.

  The reason why such a difference occurs between the adhesive produced according to the present invention and the adhesive of the reference example is that the first latent curing agent produced according to the present invention contains the content of the aluminum chelating agent in the particles. This is because the amount of curing agent necessary for low-temperature curing can be left in the particles even after washing with an organic cleaning liquid.

<Elemental analysis>
The latent curing agent after washing (second latent curing agent) produced according to the present invention was used as a powder sample, and the entire surface of the sample was coated with Os (osmium) at a film thickness of 10 nm, and then TEM (transmission). Elemental analysis was performed using a type electrophotographic microscope. A TEM photograph is shown in FIG. 10, and measurement results of elemental analysis at five locations are shown in Table 8 below.

  The column of “Al / Os” in Table 8 indicates the ratio between the Al count number and the Os count number.

  As can be seen from Table 8 above, Al remains at a high concentration at all measurement points. Since Al is derived from the main curing agent (metal chelate), it can be seen that the main curing agent remains in a high concentration and uniformly in the latent curing agent produced according to the present invention.

<Washing time>
Adhesion of Examples 20 and 21 under the same conditions as in Example 12 except that the cleaning immersion in which the first latent curing agent was immersed in an organic cleaning liquid (ethyl acetate) was changed from 4 hours to 1 hour and 8 hours, respectively. An agent was prepared and subjected to DSC analysis. The DSC chart is shown in FIG. 11, and “exothermic start temperature”, “exothermic peak temperature”, “exothermic peak intensity”, and “peak area” read from the DSC chart are shown in Table 9 below.

As is apparent from Table 9 above, even when the treatment time is changed, the curing agent characteristics such as “exothermic start temperature”, “exothermic peak temperature”, “exothermic peak intensity”, and “peak area” are equivalent. It was found that the curing agent characteristics after the treatment were stable even if the treatment time was extended.
That is, the latent curing agent produced according to the present invention has good solvent resistance to the processing solvent in that state after the solvent has penetrated into the particles in the organic solvent. Perhaps the extraction of the hardener into the solvent will stop at a certain amount.

In the solvent immersion treatment, only the main curing agent of the surface of the latent hardener particle surface that is easily extracted with the solvent is removed, so that the latent hardener that has been subjected to the cleaning treatment has improved solvent resistance to the organic cleaning liquid. doing.
Therefore, after the cleaning treatment, there is no need to dry and remove the organic cleaning liquid, and the latent curing agent after the cleaning can be used as it is added to the adhesive or the like.

<DVB replacement rate>
A first latent curing agent having a DVB substitution rate of 20% and 40% under the same conditions as in Examples 2 and 3 was prepared. The first latent curing agent was immersed in an organic cleaning liquid (ethyl acetate) and washed under the same conditions as in Examples 11 to 14 and 16 to 19 to prepare a second latent curing agent. Using the obtained second latent curing agent, adhesives of Examples 22 and 23 were prepared at the same blending ratios as in Examples 11 to 14 and 16 to 19.

  DSC analysis was performed on the adhesives of Examples 22 and 23 and the adhesive of Example 12 (DVB substitution rate 30%). The DSC chart is shown in FIG. 12. “Exothermic start temperature”, “Exothermic peak temperature”, “Exothermic peak intensity”, and “Peak area” read from the DSC chart are shown in Table 10 below.

  As apparent from Table 10 above, when the DVB substitution rate was as high as 40%, a broad peak was obtained. Since the DVB polymerized portion and the polyurea-urethane polymerized portion by isocyanate interfacial polymerization are not copolymerized, they are actually in a phase separated state. Therefore, when a certain amount or more of DVB is blended, the solvent resistance and the thermal responsiveness are lowered. From the above, it can be seen that the DVB substitution rate is preferably less than 40%.

  The above is a case where DVB and an acrylic monomer are used as the lipophilic monomer, but the lipophilic monomer is not particularly limited as long as it is not reactive with the water-reactive monomer and polymerizes by heating. . For example, when the water-reactive monomer is an isocyanate, a bifunctional or more lipophilic monomer having no hydroxyl group and amino group in the chemical structure can be widely used.

Since the first and second latent curing agents are produced using an interfacial polymerization method, the shape is spherical, and the particle diameter is preferably 0.5 μm or more from the viewpoint of curability and dispersibility. 100 μm or less.
It is preferable from the viewpoint of curing stability that the first and second latent curing agents do not substantially contain the organic solvent used during the interfacial polymerization, specifically, 1 ppm or less.

  The blending amount of the main curing agent in the oil phase liquid is not particularly limited, but in order to achieve low temperature curability during curing of the adhesive, the blending amount (weight) of the main curing agent is more than the weight of the water-reactive monomer. It is preferable to do.

Examples of the aluminum chelating agent used for the main curing agent include complex compounds in which three β-keto enolate anions are represented by the following general formula (1) and coordinated to aluminum.

Here, R ¹ , R ² and R ³ are each independently an alkyl group or an alkoxyl group. Examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkoxyl group include a methoxy group, an ethoxy group, and an oleyloxy group.

  Specific examples of the aluminum chelating agent represented by the chemical formula (1) include aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum monoacetylacetonate bis (ethylacetoacetate), and aluminum monoacetylacetonate. Examples thereof include bisoleyl acetoacetate, ethyl acetoacetate aluminum diisopropylate, and alkyl acetoacetate aluminum diisopropylate.

  Although the case where an aluminum chelate is used as the main curing agent has been described above, the present invention is not limited to this. For example, when the auxiliary curing agent in the adhesive is a silane coupling agent and a cationically polymerizable resin is used as the thermosetting resin, various metal chelates and metal alcoholates can be used. The central metal of the metal chelate and the metal alcoholate is not limited to aluminum, and various metals such as zirconium, titanium, and aluminum can be used, and among these, aluminum having particularly high reactivity is preferable.

  The water-reactive monomer is not particularly limited as long as it reacts with water and undergoes interfacial polymerization on the droplet surface. Specifically, it is an isocyanate compound, particularly two or more isocyanate groups in one molecule, preferably three. Of these, polyfunctional isocyanate compounds having an isocyanate group are preferred.

More preferable examples of the trifunctional isocyanate compound include a TMP adduct of the following chemical formula (1) obtained by reacting 3 mol of a diisocyanate compound with 1 mol of trimethylolpropane (TMP), and a chemical formula (2 ) And an isocyanurate body of 3), and a biuret body of the chemical formula (3) obtained by condensing the remaining 1 mole of diisocyanate with diisocyanate urea obtained from 2 moles of 3 moles of the diisocyanate compound.

  In the chemical formulas (1) to (3), the substituent R is a portion excluding the isocyanate group of the diisocyanate compound. Specific examples of such diisocyanate compounds include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, m-xylylene diisocyanate, hexamethylene diisocyanate, hexahydro-m-xylylene diisocyanate, isophorone diisocyanate, methylene diphenyl-4. , 4'-diisocyanate.

  A resin obtained by interfacial polymerization of such a polyfunctional isocyanate compound is a part of the isocyanate group that undergoes hydrolysis during the interfacial polymerization to become an amino group, which reacts with the amino group to react with the urea bond. It is a polyurea resin that forms a polymer by forming.

  A latent curing agent composed of a polymer of such a water-reactive monomer and a main curing agent held in a resin particle internal phase composed of a polymer of a lipophilic monomer is clearly defined when heated for curing. The reason for this is unknown, but the retained main curing agent can come into contact with the auxiliary curing agent and the thermosetting resin in the adhesive, and the curing reaction can proceed.

  The first latent curing agent is considered to have a main curing agent on the outermost surface due to its structure, but the main curing agent present on the outermost surface is present in the system during the interfacial polymerization. It is thought that the activity is weakened by water. Therefore, it is considered that the first latent curing agent before washing could acquire the potential to some extent.

  An organic solvent can be added to the oil phase liquid as necessary. The organic solvent is preferably a volatile organic solvent having a low boiling point. Here, the reason for using the volatile organic solvent is as follows. That is, when a high boiling point solvent having a boiling point exceeding 300 ° C. as used in a normal interfacial polymerization method is used, the organic solvent does not volatilize during the interfacial polymerization, so the contact probability with isocyanate-water does not increase. This is because the degree of progress of interfacial polymerization between them becomes insufficient.

  Therefore, it is difficult to obtain a polymer having good shape retention even when interfacial polymerization is performed, and even when it is obtained, a high boiling point solvent is still taken into the polymer, and when blended in an adhesive, it has a high boiling point. This is because the solvent adversely affects the physical properties of the cured product of the adhesive. For this reason, in this manufacturing method, a volatile thing is used as an organic solvent used when preparing an oil phase.

  Such a volatile organic solvent is a good solvent for each of the main curing agent, the water-reactive monomer, and the lipophilic monomer (the solubility of each is preferably 0.1 g / ml (organic solvent) or more), In particular, it is preferable that it does not substantially dissolve (the solubility of water is 0.5 g / ml (organic solvent) or less) and has a boiling point of 100 ° C. or less under atmospheric pressure. Specific examples of such volatile organic solvents include alcohols, acetate esters, ketones and the like. Among these, ethyl acetate is preferable in terms of high polarity, low boiling point, and poor water solubility.

  The amount of the volatile organic solvent used is not particularly limited, but if it is too large, not only will the work environment be adversely affected, but the amount of curing agent in the generated particles will decrease due to the dilution effect. It is desirable that the amount be less than the double amount (part by mass) of the reactive monomer.

  As the dispersant used in the aqueous phase liquid, in addition to polyvinyl alcohol, those used in usual interfacial polymerization methods such as carboxymethyl cellulose and gelatin can be used. The amount of the dispersant used is usually 0.1% by mass or more and 10.0% by mass or less of the aqueous phase.

  The emulsification conditions for preparing the suspension are, for example, stirring conditions (stirring device homogenizer; stirring speed of 8000 rpm or more) such that the size of the oil phase is preferably 0.5 μm or more and 100 μm or less. Below, the temperature is 30 ° C. or more and 80 ° C. or less, and the stirring time is 2 hours or more and 12 hours or less.

  The first and second latent curing agents produced according to the present invention can be used in the same applications as conventional imidazole-based latent curing agents, and as described above, silane coupling which is an auxiliary curing agent By using this agent in combination with a thermosetting resin, a low-temperature fast-curing adhesive can be provided.

  As described in paragraphs 0007 to 0010 of JP-A No. 2002-212537, a silane coupling agent that is an auxiliary curing agent works in cooperation with an aluminum chelating agent (for example, a thermosetting epoxy). Resin) has a function of initiating cationic polymerization.

  Such a silane coupling agent has one or more and three or less lower alkoxy groups in the molecule, and a group having reactivity to the functional group of the thermosetting resin in the molecule, for example, , Vinyl group, styryl group, acryloyloxy group, methacryloyloxy group, epoxy group, amino group, mercapto group and the like.

  A coupling agent having an amino group or a mercapto group should be used when the latent curing agent is a cationic main curing agent, so that the amino group or mercapto group does not substantially trap the generated cationic species. Can do.

  Specific examples of such silane coupling agents include vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-styryltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Acryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercapto Propyltrimethoxy Examples include silane and γ-chloropropyltrimethoxysilane.

  As the thermosetting resin, a thermosetting epoxy resin, a thermosetting urea resin, a thermosetting melamine resin, a thermosetting phenol resin, or the like can be used. Among these, a thermosetting epoxy resin can be preferably used in consideration of a good adhesive strength after curing.

  Such a thermosetting epoxy resin may be liquid or solid, and preferably has an epoxy equivalent of usually 100 or more and 4000 or less and having two or more epoxy groups in the molecule. For example, a bisphenol A type epoxy compound, a phenol novolac type epoxy compound, a cresol novolac type epoxy compound, an ester type epoxy compound, an alicyclic epoxy compound, or the like can be preferably used. These compounds include monomers and oligomers.

  The adhesive can contain a filler such as silica and mica, a pigment, an antistatic agent, and the like as necessary. The adhesive includes conductive particles having a particle size on the order of several μm, metal particles, those in which the surface of the resin core is coated with a metal plating layer, those whose surfaces are further coated with an insulating thin film, etc. It is preferable to mix | blend with the compounding quantity of 10 mass% or less of the mass%. Thereby, it becomes possible to use the adhesive manufactured by the manufacturing method of the present invention as an anisotropic conductive adhesive paste and an anisotropic conductive film.

Claims (9)

When heated in a state of being dispersed in the epoxy resin, and aluminum chelate is a main curing agent containing, said silane coupling agent is an auxiliary curing agent for the epoxy resin is in contact react epoxy resin A method for producing a latent curing agent for curing
Create an oil phase liquid containing an aluminum chelate that is a hydrolyzable main curing agent , a water-reactive monomer that polymerizes by reacting with water, and a lipophilic monomer that polymerizes by heating,
Dispersing the oil phase liquid in an aqueous phase liquid containing water as a main component to create a suspension in which droplets of the oil phase liquid are dispersed in the aqueous phase liquid,
The suspension was heated, with polymerizing the water reactive monomers, the lipophilic monomer is polymerized, it is the primary curing agent to the resin particles comprising a water-reactive monomer polymer and a lipophilic monomer polymer aluminum After creating the first latent hardener containing the chelate ,
The first latent curing agent is immersed in an organic cleaning solution containing a first organic solvent that dissolves the aluminum chelate that is the hydrolyzable main curing agent to form a second latent curing agent. A method for producing a latent curing agent. Creating the oil phase liquid, method for producing a latent curing agent of claim 1 wherein using an isocyanate as the water reactive monomer. The method for producing a latent curing agent according to claim 2, wherein the oil phase liquid is produced by containing the aluminum chelate in an amount equal to or greater than the weight of the isocyanate.   The method for producing a latent curing agent according to any one of claims 1 to 3, wherein the oil phase liquid is prepared by using one or both of a vinyl monomer and an acrylic monomer as the lipophilic monomer. The method for producing a latent curing agent according to claim 4 , wherein the production of the oil phase liquid uses divinylbenzene as the vinyl monomer. The method for producing a latent curing agent according to any one of claims 1 to 5 , wherein the cleaning of the resin particles is performed by causing the organic cleaning liquid to contain one or both of toluene and an organic carbonyl compound. The method for producing a latent curing agent according to claim 6, wherein one or both of ethyl acetate and methyl ethyl ketone is used as the organic carbonyl compound. The latent curing agent prepared by the production method according to any one of claims 1 to 7, and a second organic solvent capable of dissolving the aluminum chelate is the hydrolysis of the main curing agent, thermal The manufacturing method of the adhesive agent disperse | distributed to the binder containing the epoxy resin which is curable resin , and the silane coupling agent which is the said auxiliary | assistant hardening | curing agent. The manufacturing method of the adhesive film which removes said 2nd organic solvent from the said coating layer after forming the coating layer of the adhesive manufactured with the manufacturing method of Claim 8, and makes the said coating layer into a film.