JP2014156593A - Liquid epoxy resin composition and adhesive using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid epoxy resin composition which prevents an adhesive from flowing out from a small gap in a rotor body, can fix a magnet body, and also prevents a filler from precipitating, and an adhesive using the same.SOLUTION: A liquid epoxy resin composition contains (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler. The (C) component contains (C1) an inorganic filler having an average particle diameter of 2.0-10 μm, and (C2) an inorganic filler having an average particle diameter of 0.1-2.0 μm.

Description

  The present invention relates to a liquid epoxy resin composition capable of preventing an adhesive from flowing out of a gap between adherends and an adhesive using the same.

  Generally, a cured product obtained from an epoxy resin composition is excellent in insulation, heat resistance, adhesiveness, and the like, and is suitably used for electronic / electrical insulating materials, paints, adhesives, composite materials, and the like. For these applications, it is essential to adjust the viscosity of the liquid epoxy resin composition used in various methods such as coating, casting and impregnation in accordance with the method used.

  In particular, the viscosity of the liquid epoxy resin composition tends to decrease rapidly as the temperature increases. Thus, the change of the viscosity depending on the temperature causes a problem at the time of work, heat curing, and further long-term storage. Therefore, the liquid epoxy resin composition needs to take into account the viscosity change accompanying the temperature change at the time of use.

  Specific examples of the method include an impregnation method in the manufacture of an interior permanent magnet (hereinafter referred to as IPM) rotor. This is a method in which a magnet body is embedded in the rotor body, and an adhesive is impregnated in the gap between the rotor body and the magnet body. In this construction method, if the viscosity of the adhesive is high, it is difficult to impregnate the gap between the rotor body and the magnet body, which causes a problem in workability. In order to remedy this drawback, at the slot portion of the rotor body, one end is closed, the first adhesive is applied to the closed bottom surface, and the second adhesive is applied to the side wall surface of the open portion at the other end. A method of manufacturing an IPM rotor in which a magnet body is inserted into a rotor body and the magnet body is fixed has been proposed (Patent Document 1). However, this method is excellent in applicability, but the viscosity of the adhesive has not been studied. Therefore, if the viscosity of the adhesive changes, the adhesive will flow out from a slight gap in the rotor body, resulting in poor adhesion and appearance. It has the disadvantage of causing defects such as defects.

JP 2011-103752 A

  The adhesive impregnated in the gap between the rotor main body and the magnet body used in the manufacture of the IPM rotor described above has a drawback that the adhesive flows out from a slight gap in the rotor main body and causes problems such as poor adhesion. Therefore, appropriate viscosity adjustment is required. Furthermore, further investigations by the present inventors have revealed that the inorganic filler settles during heat curing and long-term storage even when the viscosity is adjusted so that adhesion failure does not occur.

As a result of diligent research to solve the above problems, the present inventors have found that an adhesive using a liquid epoxy resin composition containing two kinds of inorganic fillers having a specific average particle diameter can be used at room temperature. Also, at the heating and curing temperature, the adhesive does not flow out from a slight gap in the rotor body, it is possible to fix the magnet body, and the inorganic filler does not settle, and based on this finding The present invention has been completed.
That is, the present invention is as follows.

  (1) A liquid epoxy resin composition containing (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler, wherein the component (C) has (C1) an average particle size of 2.0. A liquid epoxy resin composition comprising an inorganic filler having a particle diameter of 10 to 10 μm and an inorganic filler having an average particle diameter of 0.1 to 2.0 μm.

  (2) An adhesive comprising the liquid epoxy resin composition according to (1).

  The epoxy resin composition of the present invention is a liquid epoxy resin composition containing an epoxy resin, a curing agent and a specific inorganic filler, and an adhesive using this liquid epoxy resin composition can be heated even at room temperature. Even at the curing temperature, the magnet body can be fixed without the adhesive flowing out from a slight gap in the rotor body. Furthermore, since it contains two types of inorganic fillers having a specific average particle size as an inorganic filler, it can prevent the inorganic filler from settling during heat curing or long-term storage, which is very useful for bonding applications. It is.

  The present invention is an epoxy resin composition containing (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler, and the component (C) has two types of inorganic fillers having a specific average particle diameter. It contains an agent.

  Specific examples of the component (A) include glycidyl such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, and cresol novolac type epoxy resin. Ether type epoxy resin, glycidyl ester type epoxy resin such as glycidyl ester of hexahydrophthalic acid, dimer acid glycidyl ester, glycidyl amine type epoxy resin such as triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane, brominated bisphenol A type epoxy resin, hydrogen Bisphenol A type epoxy resin, epoxy resin having biphenyl skeleton, epoxy resin having naphthalene skeleton, alicyclic epoxy resin, etc. It can be cited. In the present invention, these may be used alone or in combination of two or more.

  Specific examples of the component (B) include chain aliphatic amines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, mensendiamine, bis (4-aminocyclohexyl) methane, bis ( (Aminomethyl) cycloaliphatic amines such as cyclohexane and diaminodicyclohexylmethane, aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, diaminodiethyldiphenylmethane, benzyldimethylamine, triethylenediamine, piperidine, 2- (dimethylaminomethyl) phenol, 2 Secondary and tertiary amines such as, 4,6-tris (dimethylaminomethyl) phenol, aliphatic acid anhydrides such as maleic anhydride, dodecenyl succinic anhydride, phthalic anhydride , Cyclotrimellitic anhydride, pyromellitic anhydride and other aromatic acid anhydrides, methyl nadic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, alicyclic such as methylhexahydrophthalic anhydride Acid anhydride, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, imidazole derivatives such as 2-phenylimidazole, 3- (3,4-dichlorophenyl) -1,1-dimethylurea Urea derivatives such as 3- (p-chlorophenyl) -1,1-dimethylurea, polymercaptan compounds, polyisocyanate compounds, dicyandiamide and derivatives thereof, boron trifluoride amine complexes, organic acid hydrazides such as adipic hydrazide, and the like. Can be mentioned. In the present invention, these may be used alone or in combination of two or more.

  Specific examples of the component (C) include crystalline silica, fused silica, alumina oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, mica, talc, kaolin, clay, dolomite, titanium oxide, iron oxide, Examples thereof include carbon black and glass fiber. In the present invention, the (C1) component and the (C2) component having one or two different average particle sizes are used. Thereby, sedimentation and dispersibility of the inorganic filler and the viscosity of the resin composition can be optimized. In addition, when calcium carbonate is selected as the component (C1) and aluminum hydroxide is selected as the component (C2), the dispersion of the inorganic filler in the composition becomes uniform and the precipitation resistance is particularly preferable.

  In the present invention, the average particle diameter means a particle diameter (median diameter) at which the cumulative weight is 50%. Specifically, it refers to the average particle diameter measured using a laser diffraction particle size distribution analyzer (trade name “HELOS & RODOS” manufactured by Sympatec).

  The average particle diameter of the component (C1) needs to be 2 to 10 μm. By setting the average particle diameter to 2 μm or more, a significant increase in viscosity can be suppressed and the gaps between the adherends can be easily impregnated. Moreover, by setting it as 10 micrometers or less, it can suppress that an adhesive agent flows out from the slight clearance gap of a to-be-adhered body.

  Moreover, the average particle diameter of the said (C2) component needs to be 0.1-2 micrometers. By using a component in this range in combination with the component (C1), the inorganic filler is uniformly dispersed in the resin composition during heat curing or long-term storage, and sedimentation can be prevented.

  The mixing ratio of the component (C1) and the component (C2) is a mass ratio, and when the component (C1) is 1, the ratio of the component (C2) is in the range of 0.01 to 0.5, preferably Is 0.1 to 0.3. This makes it possible to uniformly disperse the inorganic filler in the composition, suppress sedimentation and separation, and use a rheometer CVO manufactured by Bohlin (parallel plate, diameter 25 mmφ, gap 1 mm). It is preferable because the viscosity at 100 ° C. measured can be adjusted to be 0.5 Pa · s or more. It is preferable to adjust the viscosity at 100 ° C. with this rheometer to 0.5 Pa · s or more because it is possible to suppress sagging during heat curing.

  As a compounding quantity of the said (C) component, it is especially preferable to make an upper limit into 70 mass% or less with respect to the whole quantity of an epoxy resin composition. Thereby, the fall of the fluidity | liquidity by a viscosity raise can be prevented, and workability | operativity improves especially. The lower limit is particularly preferably at least 30% by mass. Thereby, the effect which prevents the fall of sedimentation resistance by low viscosity becomes remarkable.

  The epoxy resin composition of the present invention preferably has a composition viscosity at 25 ° C. of 20 to 60 Pa · s. If a viscosity is this range, it can suppress that an adhesive agent does not flow out from the slight clearance gap of a to-be-adhered body.

  Conventionally used additives can be used in the liquid epoxy resin composition of the present invention. Specific examples include diluents, colorants, dyes, antifoaming agents, surfactants, silane coupling agents, viscosity modifiers, and the like.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

[Preparation of epoxy resin composition]
The epoxy resin composition of an Example and a comparative example was produced by mixing (A) component, (B) component, and (C) component uniformly with a planetary mixer. Tables 1 and 2 show the proportions of the constituent components.

[Components of Epoxy Resin Composition]
(A) component: bisphenol A type liquid epoxy resin (Mitsubishi Chemical Corporation make, brand name "jER828", epoxy equivalent 184-194 g / eq)

  Component (B): Alicyclic polyamine (manufactured by Air Products and Chemicals, trade name “Ancamine 2264”, amine value 502)

  Component (C1-1): Calcium carbonate (manufactured by Bihoku Flour Industry, trade name “Softon 1200”, average particle size 3.3 μm)

  (C1-2) component: Calcium carbonate (Bihoku Flour Industry, trade name “BF-200S”, average particle size 12.5 μm)

  Component (C1-3): Silica (manufactured by Tatsumori Co., Ltd., trade name “Crystallite A-1”, average particle size 9.8 μm)

  Component (C1-4): Aluminum hydroxide (manufactured by Showa Denko KK, trade name “Hijilite H-32”, average particle size: 7.0 μm)

  Component (C1-5): silica (manufactured by Nichetsu, trade name “High Silica F6A”, average particle size 4.9 μm)

Component (C1-6): fine silica (manufactured by Nippon Aerosil Co., Ltd., trade name “Aerosil 300”, average particle diameter 7 nm, specific surface area 300 cm ² / g)

  Component (C2-1): Aluminum hydroxide (manufactured by Showa Denko KK, trade name “Hijilite H-42M”, average particle size 1.6 μm)

  Component (C2-2): Silica (manufactured by Nichetsu, trade name “High Silica F6A”, average particle size 4.9 μm)

[Evaluation of epoxy resin composition]
About the obtained composition, the viscosity, flowability, and sedimentation resistance were evaluated by the measurement methods shown below. The evaluation results are shown in Tables 1 and 2.

[Evaluation of viscosity]
Using an E-type viscometer (trade name “TVE-35H”, manufactured by Toki Sangyo Co., Ltd., cone plate: diameter 28 mm, angle 3 °), at a temperature of 25 ° C., the rotor speed was arbitrarily set, and the device was After starting, the viscosity was calculated by multiplying the scale value indicated by the needle 5 minutes by a specified conversion multiplier.

[Evaluation of flowability]
Stacking thin metal plates to form an adherend, stacking them so that there is a minute gap, pouring them uniformly into the gap at room temperature, and after heat curing (curing conditions 120 ° C., 40 minutes), The degree of oozing from the stacked gap was observed and judged according to the following criteria.
○: No leaching △: There is no leaching at room temperature, but there is leaching after heat curing ×: There is oozing at room temperature

[Evaluation of sedimentation resistance]
It was stored in an atmosphere of 40 ° C. for 2 weeks in a state sealed in a container, and the state in which the filler settled and a sedimentation layer was formed at the bottom of the container was observed over time, and judged according to the following criteria.
○: No sedimentation Δ: A sedimentation layer is formed, but the composition becomes uniform by stirring. ×: A solid sedimentation layer is formed, and the composition is in a nonuniform state.

As is clear from the results in Table 1, it can be seen that the resin composition of Example 1 has good viscosity, flowability and sedimentation resistance. In particular, as the component (C), the components (C1) and (C2) were blended with an average particle diameter and a blending ratio within a predetermined range, and desired characteristics were obtained. On the other hand, the compositions of Comparative Examples 1 and 2 were prepared by blending only one type of component (C). (C1-1) Calcium carbonate (manufactured by Bihoku Flour Industry, Softon 1200, average particle size 3.3 μm) In Comparative Example 1, (C1-2) calcium carbonate (BF-200S, average particle size 12.5 μm, manufactured by Bihoku Flour Industry), and in Comparative Example 2, (C1-6) fine silica (Nippon Aerosil) It can be seen that flowability and sedimentation resistance tend to decrease.
The compositions of Examples 2 to 4 and Comparative Example 3 use (C1) component having a specific average particle diameter instead of (C1-1) in Example 1, and Examples 2 to 4 are used. Shows that the average particle size is blended within a predetermined range (2 to 10 μm), and the sedimentation resistance is good. On the other hand, in Comparative Example 3, it was found that the precipitation resistance was lowered by using (C1-2) having an average particle diameter larger than the predetermined range. On the other hand, the compositions of Comparative Examples 4 to 6 were similarly replaced with (C1-1) in Example 1, using a component (C1) having a specific average particle diameter, and (C2 In place of (-1), (C2-2) silica (manufactured by Nichez, trade name “High Silica F6A”, average particle diameter of 4.9 μm) is used. It can be seen that the sedimentation resistance was lowered by using the component (C2) having an average particle diameter larger than a predetermined range (range of 0.1 to 2 μm).

  From the above Examples and Comparative Examples, the resin composition of the present invention is adjusted to a desired viscosity by blending an epoxy resin, a curing agent, and an inorganic filler having a specific average particle diameter in a predetermined range. It is possible to fix the magnet body without flowing out of a slight gap in the adherend during normal temperature work and heat curing, and the inorganic filler is a resin composition during heat curing and long-term storage. Can be dispersed uniformly to prevent sedimentation. Therefore, it can be seen that a good viscosity is obtained and the flowability and sedimentation resistance are excellent.

  It is useful as a liquid epoxy resin composition used in the impregnation method and an adhesive using the same in the field of electronic / electrical insulating materials.

Claims (2)

  A liquid epoxy resin composition containing (A) an epoxy resin, (B) a curing agent and (C) an inorganic filler, wherein the component (C) has (C1) an average particle diameter of 2.0 to 10 μm. A liquid epoxy resin composition comprising an inorganic filler and (C2) an inorganic filler having an average particle diameter of 0.1 to 2.0 μm.   An adhesive comprising the liquid epoxy resin composition according to claim 1.