JP3098061B2 - Particulate curing agent or particulate curing accelerator, epoxy resin composition containing the same, and curing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition which uses a particulate hardener or a particulate hardener having good storage stability and mechanical strength and which does not undergo a curing reaction before use. And a curing method for causing a curing reaction.

[0002]

2. Description of the Related Art Epoxy resins are used in a wide variety of applications such as adhesives, paints, coatings, sealing materials, and laminates. Further, these epoxy resins usually contain various curing agents and curing accelerators.

[0003] Commonly used epoxy resin compositions include:
There is a so-called two-pack type composition in which a curing agent such as an amine, a Lewis acid or an acid anhydride or a curing accelerator is mixed with an epoxy resin immediately before use. In such a two-pack type, the epoxy resin and the curing agent are stored separately, and the two are mixed and used as necessary. However, since the pot life after mixing is relatively short, mix a large amount. Can not be kept, therefore
When used in a large amount, it is necessary to mix it many times little by little, and the working efficiency is extremely poor.

On the other hand, as a solution to such a problem, a latent curing agent which does not cause a curing reaction even if it is previously blended in an epoxy resin and which causes a curing reaction by light irradiation or heating is used. Various one-pack types have been proposed. However, even if these latent curing agents are used, those having excellent storage stability when blended into an epoxy resin,
The curing reaction needs to be performed under relatively high temperature conditions, and those that cure under low temperature conditions have the problem of poor storage stability, and those that have a good balance between the performance of storage stability and curability The fact is that it has not been developed yet.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the above-mentioned conventional one-part type epoxy resin composition and to provide a latent curing agent or a curing accelerator which can be used in one-part type. And Another object of the present invention is to provide an epoxy resin composition containing the above-mentioned curing agent, which has good storage stability and in which a curing reaction occurs quickly when used. It is another object of the present invention to provide a method for curing the epoxy resin composition.

[0006]

The inventors of the present invention have conducted intensive studies and have found that a curing agent or a curing accelerator is contained in fine particles of a thermoplastic polymer having a specific composition to form fine particles. It has been found that the above object can be achieved by compounding the epoxy resin with an epoxy resin to form a resin composition, and the present invention has been completed.

That is, the present invention provides a thermoplastic polymer obtained by polycondensing an aromatic monomer having a carbonyl group or a sulfonyl group in a molecule alone or with another monomer and having an average particle diameter of less than 200 μm. Within the particulate matrix of
The present invention provides a particulate hardener characterized by containing 5 to 50% by weight of a hardener having a melting point of 200 ° C. or less, and an aromatic monomer having a carbonyl group or a sulfonyl group in a molecule, or A curing accelerator having a melting point of 200 ° C. or less is contained in a fine particle matrix having an average particle size of less than 200 μm, which is made of a thermoplastic polymer obtained by polycondensation with a monomer, and has a melting point of 5 to 5 °
A particulate hardening accelerator characterized by being dispersed and contained at 0% by weight; providing an epoxy resin composition comprising an epoxy resin containing the particulate hardening agent and / or the particulate hardening accelerator; An object of the present invention is to provide a method for curing an epoxy resin composition, which comprises heating an epoxy resin composition to 60 to 150 ° C., dissolving a thermoplastic polymer in the epoxy resin, and causing a curing reaction.

The fine particle hardening agent or fine particle hardening accelerator of the present invention contains a hardening agent or hardening accelerator in fine particles made of a thermoplastic polymer, and has an average particle diameter of less than 200 μm. , Preferably 30 μm or less. When the average particle size is 200 μm or more, when the epoxy resin composition is mixed with the epoxy resin as an epoxy resin composition, it cannot be contained homogeneously, so that not only the curing reaction does not occur uniformly, but also the curing time becomes longer. Absent.
The average particle size in the present invention is calculated from a particle size distribution diagram using a sedimentation type particle size distribution analyzer.

In the present invention, the thermoplastic polymer constituting the particulate hardener or the particulate hardener is obtained by polycondensing an aromatic monomer having a carbonyl group or a sulfonyl group in the molecule alone. Alternatively, it can be obtained by copolycondensing these monomers with another polycondensable monomer. The thermoplastic polymer obtained preferably has a high mechanical strength and has a glass transition temperature of 120 ° C. or higher in order to withstand the shearing stress applied during mixing and mixing with the epoxy resin. In the present invention, those having a weight-average molecular weight of about 2,000 to 1,000,000 are preferable from the viewpoints of fine particle formability and cured film formation from the epoxy resin composition. Specific examples of such thermoplastic polymers include aromatic thermoplastic resins such as polysulfone, polyethersulfone, polyarylate, polycarbonate, polyetheretherketone, polyallylsulfone, and polyetherimide.

On the other hand, the curing agent or the curing accelerator contained in the fine particle curing agent or the fine particle curing accelerator has a melting point of 200 ° C. or lower, preferably 1 ° C., from the viewpoint of curability.
Those having a temperature of 50 ° C. or lower are used, and they may be liquid or solid at room temperature. These fine particle hardeners or fine particle hardening accelerators are used in an amount of 5 to 50% by weight, preferably 10 to 30% by weight, from the viewpoint of homogeneous curing reactivity and storage stability. It is contained. When the amount is less than 5% by weight, the curing time tends to be long. When the amount exceeds 50% by weight, the amount of the thermoplastic polymer becomes small, so that the mechanical strength of the fine particles is insufficient. At the same time, the storage stability when mixed with an epoxy resin is undesirably reduced.

Specific examples of such curing agents include aliphatic tertiary amines such as tributylamine, benzyldimethylamine, 2- (dimethylaminomethyl) phenol, and 2,4,6-tris (diaminomethyl) phenol. Such as aromatic tertiary amines and alicyclic tertiary amines, or modified amines thereof, 2-methylimidazole,
-Ethylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, 2-dodecylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1
Imidazoles such as benzyl-2-methylimidazole and 1-cyanoethyl-2-methylimidazole; these imidazoles and acetic acid, lactic acid, salicylic acid, benzoic acid, adipic acid, phthalic acid, citric acid, tartaric acid, maleic acid, triic acid; An imidazole carboxylate with merit acid or the like, or a Lewis acid such as boron trifluoride or phosphorus pentafluoride can be used. In the present invention, even if a small amount of these curing agents are blended, a sufficient curing reaction occurs,
An optional amount of a commonly used known curing accelerator can be blended.

[0012] Examples of the curing accelerator which is contained in fine particles to accelerate the curing reaction include alkyl-substituted guanidines such as ethylguanidine, trimethylguanidine, phenylguanidine and diphenylguanidine;
-(3,4-dichlorophenyl) -1,1-dimethylurea, 3-phenyl-1,1-dimethylurea, 3- (4-
3-substituted phenyl-1,1-dimethylureas such as (chlorophenyl) -1,1-dimethylurea, imidazolines such as 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline and 2-heptadecylimidazoline; Monoaminopyridines such as 2-aminopyridine, N, N-dimethyl-N- (2-hydroxy-
Examples thereof include amine imides such as (3-allyloxypropyl) amine-N'-lactide, triphenylphosphine, and salts thereof.

The fine-particle hardener or fine-particle hardening accelerator of the present invention comprising the above-mentioned hardening agent or hardening accelerator in a fine-particle thermoplastic polymer can be prepared, for example, by a spray drying method, a coacervation method, It can be obtained by a method such as a middle drying method. The content of the curing agent or the curing accelerator in the obtained fine particles is such that the curing agent or the curing accelerator is dispersed in a matrix formed of a thermoplastic polymer from the viewpoint of uniform curing reactivity and mechanical strength. In a dispersed content state. Depending on the purpose, a curing agent and a curing accelerator may be used together in the fine particles.

The epoxy resin composition of the present invention contains 1 to 80 parts by weight, preferably 3 to 40 parts by weight of the above-mentioned fine particle curing agent and / or fine particle curing accelerator based on 100 parts by weight of epoxy resin from the viewpoint of curability. It can be obtained by blending in a ratio of parts by weight and, if necessary, blending a latent curing agent, various fillers, additives and the like.

The epoxy resin used may be liquid or solid, and usually has an epoxy equivalent of 100 to 3
Those having about 500 and having an average of two or more epoxy groups in one molecule can be preferably used. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, cycloaliphatic epoxy resin, hydantoin epoxy resin, novolak type epoxy resin, glycidyl ester type epoxy resin, etc. may be used alone or in combination of two or more. it can. Of these, it is preferable to use a bisphenol A type epoxy resin from the viewpoint of compatibility with the thermoplastic polymer constituting the fine particles, practicality, and economy.

As the latent curing agent which can be arbitrarily compounded, a latent curing agent used for heat curing as an epoxy resin curing agent can be usually used, and specific examples thereof include dicyandiamide-based, imidazole-based, and phenol-based curing agents. System, acid anhydride system, acid hydrazide system, fluorinated boron compound system,
Examples of the curing agent include epoxy resin curing agents such as amine imides and amine resins. These can be used alone or in combination of two or more. The curing agent is added and mixed in a range of 40 parts by weight or less based on 100 parts by weight of the epoxy resin.

Further, fillers which can be contained in the epoxy resin composition of the present invention, if necessary, include silica, clay, gypsum, calcium carbonate, barium sulfate, and the like.
Quartz powder, glass fiber, kaolin, mica, alumina, hydrated alumina, aluminum hydroxide, talc, dolomite, zircon, titanium compounds, molybdenum compounds, antimony compounds, etc., silane coupling agents and pigments, antioxidants, Other optional additive components can be appropriately blended according to the purpose and use. In addition, copper or zinc,
Metallic powders of nickel, cadmium, stainless steel, aluminum, silver, and the like, preferably zinc, nickel, stainless steel, and aluminum may be blended to impart conductivity to the composition of the present invention. When imparting conductivity, it is preferable to mix the above metal powder in an epoxy resin composition in an amount of 25% by weight or more.

The composition of the present invention containing the above components is uniformly dispersed at room temperature using a roll, a mixer, a Henschel mixer, a ball mill, a kneader, a disper, or the like.
The composition of the present invention can be obtained by mixing.

The above-mentioned epoxy resin composition is heated to a predetermined temperature or higher to dissolve the thermoplastic polymer constituting the fine particle curing agent or the fine particle curing accelerator in the epoxy resin to cause a curing reaction. The heating temperature varies depending on the type and amount of the thermoplastic polymer and the type and amount of the epoxy resin.
Heat to a temperature of about 0-150 ° C. By such heating, the thermoplastic polymer constituting the fine particles gradually becomes compatible with the epoxy resin, and the curing agent or the curing accelerator contained therein causes a curing reaction with the epoxy resin. Although the compatibility mechanism between the thermoplastic polymer and the epoxy resin is not clear, it is presumed that carbonyl groups and sulfonyl groups present in the thermoplastic polymer are involved.

[0020]

The present invention will be specifically described below with reference to examples. Hereinafter, parts and% in the text mean parts by weight and% by weight, respectively.

Example 1 Polysulfone as a thermoplastic polymer (trade name: Udel P-3500, manufactured by Amoco, Tg 189 ° C.) and 1-benzyl-2-methylimidazole as a curing agent (melting point 40 to 50 ° C.) Was used to obtain a particulate hardener of the present invention by a submerged drying method. This particulate hardener had a spherical shape with an average particle size of 8 μm, and as a result of elemental analysis, the content of the hardener was 20%. FIG. 1 shows a scanning electron micrograph of the particle structure of the obtained particulate hardener.

Twenty parts of the particulate hardener thus obtained was mixed with a bisphenol A type epoxy resin (epoxy equivalent: about 190, weight average molecular weight: 380, viscosity: 125 poise (2
5 ° C.)), kneaded at room temperature for 1 hour in a mixing kettle, and further passed through a three-roll mill to obtain the epoxy resin composition of the present invention.

Example 2 The epoxy resin composition of the present invention was prepared in the same manner as in Example 1 except that the content of the curing agent in the fine particle curing agent was 40% and the number of components in the epoxy resin composition was 10 parts. I got

Comparative Example 1 An epoxy resin composition was obtained in the same manner as in Example 1, except that the content of the curing agent in the fine particle curing agent was 4% and the number of parts in the epoxy resin composition was 100 parts. .

Comparative Example 2 Example 1 was repeated except that the content of the curing agent in the particulate curing agent was 60% and the number of parts in the epoxy resin composition was 7 parts.
In the same manner as in the above, an epoxy resin composition was obtained.

Comparative Example 3 An epoxy resin was prepared in the same manner as in Example 1 except that 1-benzyl-2-methylimidazole was used in place of the fine particle curing agent, and the number of parts blended in the epoxy resin composition was changed to 4 parts. A resin composition was obtained.

Example 3 The average particle size was changed in the same manner as in Example 1 except that the thermoplastic polymer used in Example 1 was changed to polyether sulfone (trade name: Victrex 100P, manufactured by ICI, Tg 225 ° C.). A particulate hardener having a diameter of 10 μm (hardener content: 18%) was obtained, and an epoxy resin composition of the present invention was obtained in the same manner as in Example 1 below.

Example 4 Amorphous polyarylate as a thermoplastic polymer (trade name: U-Polymer (U-100), manufactured by Unitika Ltd., Tg2
03 ° C.) and 2-undecylimidazole (melting point 71 ° C.) as a curing agent to obtain a particulate curing agent of the present invention by a coacervation method. The particulate hardener was spherical with an average particle size of 9 μm, and as a result of elemental analysis, the hardener content was 32%.

13 parts of the particulate hardener obtained in this way was mixed with a bisphenol A type epoxy resin (epoxy equivalent: about 190, weight average molecular weight: 380, viscosity: 125 poise (2
5 ° C.)), kneaded at room temperature for 1 hour in a mixing kettle, and further passed through a three-roll mill to obtain the epoxy resin composition of the present invention.

Comparative Example 4 An epoxy resin composition was prepared in the same manner as in Example 4 except that 2-undecylimidazole was used in place of the fine particle curing agent, and that the number of parts blended in the epoxy resin composition was changed to 4 parts. I got

Example 5 Example 4 was repeated except that the thermoplastic polymer used in Example 4 was changed to polyetherimide (trade name: Ultem 1000, manufactured by GE Plastics, Tg 217 ° C.).
In the same manner as in Example 1, a particulate hardener having an average particle size of 15 μm (hardener content: 25%) was obtained. In the same manner as in Example 4, the epoxy resin composition of the present invention was obtained.

Example 6 An average particle diameter of 7 μm was obtained in the same manner as in Example 1 except that the curing agent used in Example 1 was changed to benzyldimethylamine.
m of a particulate hardener (hardener content: 20%) was obtained, and 15 parts of the particulate hardener was added to 100 parts of the epoxy resin used in Example 1 and mixed to obtain an epoxy resin composition of the present invention. Was.

Comparative Example 5 An epoxy resin composition was obtained in the same manner as in Example 6 except that benzyldimethylamine was used instead of the fine particle curing agent, and the number of parts to be mixed in the epoxy resin composition was changed to 3 parts. Was.

Example 7 The thermoplastic polymer used in Example 6 was polyallyl sulfone (trade name: Radel A-100, manufactured by Amoco Co., Ltd., T
g220 ° C.) except that the fine particle-shaped hardener having an average particle size of 10 μm (hardener content 15%) was used in the same manner as in Example 6.
Was obtained, and an epoxy resin composition of the present invention was obtained in the same manner as in Example 6.

Comparative Example 6 An average was obtained in the same manner as in Example 1 except that the thermoplastic polymer used in Example 1 was changed to polymethyl methacrylate (trade name: SUMIPEC-B, manufactured by Sumitomo Chemical Co., Ltd., Tg: 105 ° C.). Fine particle hardener with a particle size of 6 μm (hardener content 1
8%), and 23 parts of the particulate hardener was added to and mixed with 100 parts of the epoxy resin used in Example 1 to obtain an epoxy resin composition of the present invention.

Comparative Example 7 An average was obtained in the same manner as in Example 1 except that the thermoplastic polymer used in Example 1 was changed to polystyrene (trade name: Denkabutyral HRM-2, manufactured by Denki Kagaku Kogyo Co., Ltd., Tg 100 ° C.). 8 μm particle size hardener (hardener content 1
6%), and 25 parts of the particulate hardener was added to and mixed with 100 parts of the epoxy resin used in Example 1 to obtain an epoxy resin composition of the present invention.

Example 8 Except that 4 parts of dicyandiamide was further added as a latent curing agent to the epoxy resin composition of Example 1,
An epoxy resin composition of the present invention was obtained in the same manner as in Example 1.

Example 9 To 40 parts of the epoxy resin composition in Example 3, 4 parts of dicyandiamide as a latent curing agent and bisphenol A
An epoxy resin composition of the present invention was obtained in the same manner as in Example 3, except that 60 parts of a type epoxy resin (as described above) was blended. In addition, in the case of this example, 1
-Benzyl-2-methylimidazole was used as a curing accelerator.

Comparative Example 8 In Example 8 (or Example 9), 1-benzyl-2-methylimidazole was used in place of the fine particle curing agent (or the fine particle curing accelerator), and the mixture was introduced into the epoxy resin composition. An epoxy resin composition was obtained in the same manner as in Example 8 (or Example 9) except that the number of components was changed to 1 part.

Example 10 Polyether sulfone used in Example 3 and 3- (3,4-dichlorophenyl) -1,1 as a curing accelerator
-A particulate hardening accelerator of the present invention was obtained by an in-liquid drying method using dimethyl urea (melting point: 158 ° C). This particulate hardening accelerator was spherical with an average particle diameter of 10 μm, and as a result of elemental analysis, the content of the hardening accelerator was 33%.

The particulate hardening accelerator 1 thus obtained
5 parts, 100 parts of a bisphenol A type epoxy resin (epoxy equivalent: about 190, weight average molecular weight: 380, viscosity: 125 poise (25 ° C.)), and 8 parts of dicyandiamide as a latent curing agent are mixed at room temperature for 1 hour at room temperature. After kneading, the mixture was further passed through a three-roll mill to obtain an epoxy resin composition of the present invention.

Comparative Example 9 Instead of the particulate hardening accelerator, 3- (3,4-dichlorophenyl) -1,1-dimethylurea was used and the number of parts to be mixed in the epoxy resin composition was changed to 5 parts. In the same manner as in Example 10, an epoxy resin composition was obtained.

The properties of the epoxy resin compositions obtained in the above Examples and Comparative Examples were measured in accordance with the following test methods, and the results are shown in Table 1.

<Mechanical Stability> Each composition was passed through a three-roll mill, and the shapes before and after passing were observed with an optical microscope. The judgment is as follows.・ ・ ・: No change is observed before and after passing through the roll. X: The particulate hardener was crushed after passing through the roll.

<Dissolution Initiation Temperature> Each composition was placed under a heating rate of 10 ° C./min, and the behavior of the thermoplastic polymer constituting the fine particles dissolving in the epoxy resin was observed with an optical microscope. The starting temperature was measured. The dissolution behavior in the epoxy resin composition obtained in Example 1 is shown in FIGS. Although it did not dissolve at 25 ° C. (FIG. 2), it started dissolving at 90 ° C. (FIG. 3) and completely dissolved at 100 ° C. (FIG. 4) to form bubbles.

<Reaction initiation temperature> Temperature at which an exothermic peak starts to rise using a differential thermal analyzer (curing reaction initiation temperature).
Was measured.

<Storage Stability> The composition was stored under the conditions of 20 ° C. and 40 ° C., and the change in viscosity over time was observed, and the number of days required until the viscosity became three times or more the initial viscosity was measured.

<Curability> The curing time at 120 ° C. was measured by a hot plate gel time measuring method. In Example 10 and Comparative Example 9, the measurement temperature was 150 ° C.

<Adhesiveness> Steel plate (SPCC-SD: 100
× 25 × 1.6 ^t mm) with an adhesion area of 25 × 12.5m
m, and applied at a layer thickness of 0.12 mm, and cured under the conditions of 120 ° C. × 15 minutes to prepare a test piece. Example 1
For 0 and Comparative Example 9, the curing condition was 150 ° C. × 15.
Minutes.

The shear strength of the obtained test piece was measured using a Tensilon tensile tester (tensile speed: 5 mm).
/ Min, measurement temperature 23 ° C).

[0051]

[Table 1]

[0052]

As described above, the particulate hardener or particulate accelerator of the present invention can be easily blended with an epoxy resin, has sufficient mechanical strength, and has storage stability and curability. It is intended to provide a well-balanced epoxy resin composition excellent in various properties such as the above.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph (× 5000) showing the particle structure of a particulate hardener obtained in Example 1.

FIG. 2 is a scanning electron micrograph (× 400) showing a particle structure that changes when the epoxy resin composition obtained in Example 1 is heated to 25 ° C.

FIG. 3 is a scanning electron micrograph (× 400) showing a particle structure that changes when the epoxy resin composition obtained in Example 1 is heated to 90 ° C.

FIG. 4 is a scanning electron micrograph (× 400) showing a particle structure that changes when the epoxy resin composition obtained in Example 1 is heated to 100 ° C.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 59/40-59/66

Claims (6)

(57) [Claims] 1. An average particle size of a thermoplastic polymer obtained by polycondensing an aromatic monomer having a carbonyl group or a sulfonyl group in a molecule alone or with another monomer.
200 ° C. in a fine particle matrix of less than 00 μm
A particulate hardener comprising the following hardener dispersedly in an amount of 5 to 50% by weight. 2. An average particle size of a thermoplastic polymer obtained by polycondensing an aromatic monomer having a carbonyl group or a sulfonyl group in a molecule alone or with another monomer.
200 ° C. in a fine particle matrix of less than 00 μm
Particulate curing accelerator, characterized in that it contains the following curing accelerator 5-50 weight percent dispersion. 3. An epoxy resin composition comprising the epoxy resin and the particulate hardener according to claim 1. An epoxy resin composition comprising the epoxy resin and the particulate curing accelerator according to claim 2. 5. The epoxy resin composition according to claim 3, further comprising a heat-curable latent curing agent. 6. An epoxy resin, wherein the epoxy resin composition according to claim 3 is heated to 60 to 150 ° C. to dissolve the thermoplastic polymer in the epoxy resin and cause a curing reaction. The method of curing the composition.