JP2009013346A - Polyamic acid fine particle or polyimide fine particle, and method for producing polyamic acid fine particle and polyimide fine particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a globular composite polyimide fine particle and polyamic acid fine particle having a flat and smooth surface, and to provide a method for producing the same. <P>SOLUTION: The polyamic acid fine particle or polyimide fine particle has, on an outer layer of a core fine particle (D), at least two layers of a polyamic acid layer and/or a polyimide layer, and has a flat and smooth surface the surface roughness of which is <20 nm. It is preferable that the thickness of the polyamic acid layer and/or the polyimide layer, both provided on the outer layer of the core fine particle (D), be 0.1-400 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to polyamic acid fine particles or polyimide fine particles, a method for producing polyamic acid fine particles, and a method for producing polyimide fine particles.

Since polyimide has excellent heat resistance and electrical properties, it is widely used in various fields such as electronic materials, liquid crystals, adhesives, and paints as heat-resistant materials and insulating materials in various forms such as films, coating agents, and fine particles. It has been. If this polyimide can be produced as uniform fine particles, it is very useful as an electric / electronic material.

  Conventionally, polyimide fine particles are prepared, for example, by reacting a tetracarboxylic dianhydride and a diamine compound in a solvent in which a polyamic acid such as N-methylpyrrolidone (NMP) or N, N-dimethylformamide is soluble to prepare a varnish. In addition, there are known a method in which the varnish is heated and the imidization reaction proceeds to cause precipitation due to a difference in solubility, and a polyimide solid is pulverized to adjust fine particles. However, many of the polyimide fine particles obtained by these methods are indefinite, have a wide particle size distribution, and have a large particle size, so that they have not developed much in various fields such as the electronic materials field.

Therefore, a method for producing fine polyamic acid particles in which a tetracarboxylic anhydride solution and a diamine solution are mixed, polyamic acid is precipitated from the mixed solution, and the particle shape, particle size distribution and the like can be controlled has been proposed. (Patent Document 1) According to this method, polyimide fine particles having a single particle shape and a uniform particle distribution can be obtained.

However, in recent years, with the recent development in each field such as the electronic materials field, finer materials have been required to have higher levels of mechanical strength, low thermal expansion, insulation, etc. It has become clear that these polyimides cannot meet these requirements.

Under such circumstances, the technology that combines materials with different characteristics in film shape and other molded products to improve performance is used, and these composite methods were also used for polyimide fine particles. An example has been proposed (for example, Patent Document 2). In this method, a molecular chain of a polyimide precursor is grown from the seed particle surface for multilayering, and this is imidized to form a layer of polyimide fine particles having a thickness of about 3 to 1000 nm. Has a problem that since the surface layer is formed of polyimide fine particles, there are irregularities on the surface and it is difficult to control the shape.

Further, in the above production method, the molecular chain length grown from the seed particles has an influence on the thickness of the layer, and the molecular chain length obtained in the synthesis is limited, so that the layer thickness is limited. Furthermore, side reactions (polyaddition and polycondensation reactions) that occur in the reaction liquid are more likely to occur during the reaction than the growth on the seed particles, and the industrialization is difficult because the reaction yield is low.
JP-A-11-140181 JP 2004-10653 A

An object of the present invention is to provide spherical composite polyimide fine particles having a smooth surface, composite polyamic acid fine particles which are precursors thereof, and a method for producing the same.

As a result of intensive studies to solve the above problems, the present inventor has controlled the reaction conditions, preferentially deposits components having different characteristics on the surface of the polyamic acid fine particles or polyimide fine particles, and isotropic polyamic It has been found that polyimide particles having a smooth surface with a surface roughness of less than 20 nm can be obtained by forming an acid layer and imidizing it by heating in a temperature range in which the movement of molecular chains can be suppressed. Was completed.

  That is, the present invention provides polyamic acid or polyimide fine particles having a smooth surface with at least two polyamic acid layers and / or polyimide layers in the outer layer of the core fine particles (D) and having a surface roughness of less than 20 nm; The tetracarboxylic acid anhydride (A) and the diamine compound (B) are mixed and reacted in the presence of the core material fine particles (D) and precipitated on the core material fine particles (D). After forming a polyamic acid layer to form seed fine particles (C), the tetracarboxylic acid anhydride (A) and the diamine compound (B) (however, the tetralayer used when the component layer was formed on (D)) At least one of carboxylic acid anhydride (A) and diamine compound (B) is mixed and reacted) to form a polyamic acid layer on seed fine particles (C). Method for producing a polyamic acid according to claim Rukoto and a process for producing a polyimide fine particles, characterized by imidizing polyamic acid particles obtained in the method a glass transition temperature below components.

  According to the present invention, spherical polyamic acid composite fine particles and polyimide composite fine particles having a multilayer structure in which the number of layers, the layer thickness, etc. can be easily controlled and having a smooth particle surface can be obtained. In addition, polymer fine particles having desired physical properties can be obtained by changing the composition, introduction amount, and the like of each layer. Furthermore, porosity can be introduced between the layers by forming polyamic acid layers having different volume shrinkage rates during imidization. Since the introduction of porosity can change the refractive index significantly, it can be applied to optical materials.

In addition, since the fine particles of the present invention have a smooth surface, they can be applied to, for example, optical fine particle materials using a phase difference, and composite fine particles having a particle size of about 1.0 to 100 μm suitable for these can be easily used. Can be manufactured. The smoothness of the particle surface has a great influence on the optical properties and mechanical properties, and in particular for hard but brittle polyimides, for example, in applications that require mechanical properties, Since it causes local destruction, the fine particles of the present invention are effective in improving these performances.

The polyamic acid or polyimide fine particles of the present invention (hereinafter, polyamic acid or polyimide fine particles may be referred to as “polyimide fine particles”) are present in the outer layer of the core fine particles (D) (hereinafter referred to as “component (D)”). It has a polyamic acid layer and / or a polyimide layer, and has a smooth surface with a surface roughness of less than 20 nm. Here, the surface roughness is expressed by Equation 1: Surface roughness (nm) = Σ {(L _H1 + L _H2 + L _H3 + L _H4 + L _H5 ) / 5- (L _L1 + L _L2 + L _L3 + L _L4 + L _L5 ) / 5} / n (where L _Hx is the radius of the convex portion (nm) and represents the xth longest radius in the measurement portion, and L _Lx is the radius of the concave portion (nm)) Where x represents the xth shortest radius in the measurement part, and n represents the number of samples. That is, an average value obtained by observing a cross section of n (number of samples) fine particles with a transmission electron microscope (TEM) and dividing the sum from the longest radius to the fifth longest radius by 5. This is a value obtained by calculating the difference between the average values obtained by dividing the sum from the shortest radius to the fifth shortest radius by 5, adding them, and then dividing by n.

  (D) component used for this invention becomes a nucleus of the polyamic acid of this invention, or a polyimide microparticle. The material for the component (D) is not particularly limited, and known materials can be used. Specifically, inorganic fine particles such as silica and alumina can be used in addition to organic polymer fine particles such as polyimide, polyamic acid, polyamide, polyurethane, cross-linked polystyrene resin, and cross-linked acrylic resin. The particle size of the component (D) may be appropriately selected according to the desired particle size of the polyamic acid or polyimide fine particles. In addition, in order to make the surface of the polyamic acid or polyimide fine particle finally obtained smooth, it is preferable to use a smooth surface for the component (D). As the component (D), for example, polyamic acid fine particles or polyimide fine particles prepared by a method described in JP-A-2006-183018, JP-A-11-140181, or the like is preferably used.

The polyamic acid fine particles, which are the precursors of the polyimide fine particles, are, for example, tetracarboxylic anhydride (A) (hereinafter referred to as (A) component) and diamine compound (B) (hereinafter referred to as (D) in the presence of component (D). B) component) is mixed and reacted, and precipitated on (D) to form a polyamic acid layer on (D) component to form seed fine particles (C) (hereinafter referred to as (C) component). Further, at least one of the tetracarboxylic acid anhydride (A) and the diamine compound (B) used when the component layer is formed on the component (A) and the component (B) (D) is different. And a polyamic acid layer is further formed on the component (C). Here, in the component (C), the constituent materials of the polyamic acid in the outermost layer and the layer below it are different. Then, by repeating the same operation n-2 times using the thus obtained fine particles having two polyamic acid layers, fine particles having n polyamic acid layers can be obtained. In addition, when synthesizing multi-layered polyamic acid fine particles having n layers, the component (C) refers to multi-layered polyamic acid fine particles having (n-1) layers. Polyimide fine particles having a multilayer structure can be obtained by imidizing the thus-obtained multilayer polyamic acid fine particles at a temperature below the glass transition point of the constituent components.

  As (A) component used for this invention, if it is the tetracarboxylic acid anhydride normally used for manufacture of a polyimide, it will not specifically limit, A well-known thing can be used. Specifically, for example, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3, 3 ', 4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride (PMDA), 1,3-bis (2,3-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (2 , 3-dicarboxyphenoxy) benzene dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 2, 2 ', 3,3'-biphenyltetracarboxylic dianhydride, 2,2', 6,6'-biphenyltetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride , Anthracene-2,3 Aromatic tetracarboxylic dianhydrides such as 6,7-tetracarboxylic dianhydride and phenanthrene-1,8,9,10-tetracarboxylic dianhydride; butane-1,2,3,4-tetracarboxylic Aliphatic tetracarboxylic dianhydrides such as acid dianhydrides; Alicyclic tetracarboxylic dianhydrides such as cyclobutane-1,2,3,4-tetracarboxylic dianhydride; Thiophene-2,3,4 , 5-tetracarboxylic dianhydride, heterocyclic tetracarboxylic dianhydrides such as pyridine-2,3,5,6-tetracarboxylic anhydride and the like can be used. These may be used alone or in combination of two or more. In the present invention, BTDA, pyromellitic dianhydride and the like are particularly preferable. Moreover, in this invention, what substituted some tetracarboxylic anhydrides with the corresponding tetra acid chloride can be used.

  Further, within the range not impairing the effects of the present invention, tricarboxylic acids such as trimellitic anhydride, butane-1,2,4-tricarboxylic acid, naphthalene-1,2,4-tricarboxylic acid, oxalic acid, malonic acid, Acid anhydrides of aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, vimelic acid, suberic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, isophthalic acid, terephthalic acid, diphenylmethane-4, An acid anhydride of an aromatic dicarboxylic acid such as 4′-dicarboxylic acid can be used in combination. However, since the heat resistance of the resulting polymer tends to be deteriorated when the proportion of tetracarboxylic acids is too large, the amount used is preferably 30 mol% or less in the component (A).

  As (B) component used for this invention, if it is diamine normally used for manufacture of a polyimide, it will not specifically limit, A well-known thing can be used. Specifically, for example, 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenyl ether (DPE), 4,4'-bis (4-aminophenoxy) biphenyl (BAPB), 1,4 ' -Bis (4-aminophenoxy) benzene (TPE-Q), 1,3'-bis (4-aminophenoxy) benzene (TPE-R), 1,5-bis (4-aminophenoxy) alkane (DA5MG), 1,4-bis (4-aminophenoxy) alkane (DA4MG), 1,3-bis (4-aminophenoxy) alkane (DA3MG), o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,4 '-Diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4-diaminodiphenyl sulfone, 3 3'-diaminodiphenylsulfone, 4,4'-methylene-bis (2-chloroaniline), 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfide, 2,6 ' -Diaminotoluene, 2,4-diaminochlorobenzene, 1,2-diaminoanthraquinone, 1,4-diaminoanthraquinone, 3,3'-diaminobenzophenone, 3,4-diaminobenzophenone, 4,4'-diaminobenzophenone, 4, Aromatic diamines such as 4'-diaminobibenzyl, R (+)-2,2'-diamino-1,1'-binaphthalene, S (+)-2,2'-diamino-1,1'-binaphthalene; 1,2-diaminomethane, 1,4-diaminobutane, tetramethylenediamine, aliphatic diamines such as 1,10-diaminododecane, In addition to alicyclic diamines such as 4-diaminocyclohexane, 1,2-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 4,4′-diaminodicyclohexylmethane, 3,4-diaminopyridine, 1,4-diamino -2-butanone or the like can be used. These can be used alone or in combination of two or more. In the present invention, other amines (monoamine, triamine, etc.) can be used as long as the effects of the present invention are not impaired. Among these, DPE, TPE-R, DA5MG, etc. are particularly used. preferable.

  The component (A) and the component (B) are preferably used as a solution by previously dissolving the component (A) and the component (B) in a solvent from the viewpoint of suppressing the progress of the side reaction. In addition, as a solvent used when preparing (A) component solution and (B) component solution, it does not react with (A) component and (B) component, but dissolves (A) component and (B) component. In addition, any known polymer can be used without particular limitation as long as the polymer to be produced is insoluble or hardly soluble.

  Specific examples include ketone solvents, chlorine solvents, ether solvents, ester solvents, nitrile solvents, amide solvents, aromatic solvents, and the like. More than one species may be used in combination. Examples of the ketone solvent include acetone and methyl ethyl ketone (MEK). Examples of the chlorinated solvent include chloroform, dichloromethane, carbon tetrachloride, dichloroethane and the like. Examples of the ether solvent include diethyl ether. Examples of ester solvents include methyl acetate and ethyl acetate. Examples of the nitrile solvent include acetonitrile, propionitrile and the like. Examples of amide solvents include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) and the like. Aromatic solvents include benzene, toluene, xylene and the like. Among these, ketone solvents, ester solvents, nitrile solvents, and ether solvents are preferably used, and ketone solvents and ether solvents are particularly preferable. In addition, even if the solvent of the polyamic acid is high, such as an aprotic polar solvent such as DMF, DMAc, or NMP, it is mixed with a poor solvent of the polyamic acid such as acetone, methyl acetate, MEK, toluene, xylene. These can also be used if they are adjusted to produce polyamic acid fine particles.

  The concentration of the component solution (A) may be appropriately set according to the type of the component (A) to be used, the concentration of the component solution (B), the viscosity of the solution, etc., but is usually 0.001 to 1 mol. / Liter, preferably 0.01 to 0.1 mol / liter.

  The concentration of the component solution (B) may be appropriately set according to the type of the component (B) to be used, the concentration of the component solution (A), the viscosity of the solution, etc., but is usually 0.001 to 1 mol. / Liter, preferably 0.01 to 0.1 mol / liter.

  (C) component used for this invention becomes a core material of microparticles | fine-particles, such as a polyimide to manufacture. The composition and particle size of the middle deep part (component (D)) in component (C) are not particularly limited. Specific gravity, solubility in the solvent system used, dispersion stability, adhesion to polymer component and desired It may be appropriately selected in consideration of the physical properties of the polymer fine particles. The component (D) preferably has a bonding mode or functional group having a high affinity for the polyamic acid to be deposited, and polyamic acid or polyimide is preferred. Moreover, as a particle diameter, a thing about 0.1-400 micrometers can be used, What is necessary is just to use a thing smaller than the particle diameter of the polymer fine particle desired. In particular, it is particularly preferable to use particles having a uniform particle shape and particle diameter because uniform polymer fine particles can be easily obtained. In addition, a dispersion stabilizer can also be used as needed for the purpose of stably dispersing the component (D) in the polymerization solvent.

  The component (C) of the polymer fine particle of the present invention is prepared by, for example, mixing and reacting the components (A) and (B) in the presence of the component (D) in a solvent to form a polymer formed on the surface of the component (D) It is obtained by depositing on top and forming a polymer layer. Specifically, for example, the (A) component, the (B) component, the (D) component and the solvent are charged all at once, mixed and polymerized, and in the presence of the (D) component, (B) Method of polymerizing while supplying a mixed solution in which component solutions are mixed, Method of mixing and polymerizing while (A) component solution and (B) component solution are separately supplied in the presence of component (D) Etc. can be selected. In particular, from the viewpoint of easy control of polymerization and particle growth, a method of supplying a mixed solution obtained by previously mixing the (A) component solution and the (B) component solution in the presence of the (D) component is preferable. In addition, as a method of mixing the component solution (A) and the component solution (B), a method of mixing using a micromixer is preferable because mixing efficiency is high, temperature control is easy, and reaction control is easy. In the present invention, the micromixer has a space where two or more inflow paths and one or more outflow paths and the two or more inflow paths merge, and the diameter of the inflow path leading to the merge space is The thing which is about 0.01-100 micrometers. In addition, when supplying the liquid mixture which mixed (A) component solution and (B) component solution beforehand, in order to form a polymer layer on the (D) component surface, (A) component solution and (B) component solution are used. In the step of preparing a mixed solution by mixing, it is necessary to set reaction conditions so that polymer precipitation does not occur. When the formation of a polymer other than the surface of the (D) component of the generated polymer occurs, the growth of particles using the (D) component as a seed and the formation of new particles and the growth of particles using the generated new particles as a seed simultaneously As a result, the particle size distribution spreads and it becomes difficult to control the particle size. Moreover, it does not specifically limit as a mixing method at the time of superposition | polymerization, What is necessary is just to employ | adopt a well-known method. Specifically, for example, mixing may be performed by stirring with a stirring blade or the like, or ultrasonic irradiation may be performed. For the ultrasonic irradiation, a known ultrasonic device and operating conditions may be adopted as appropriate. Specifically, for example, the ultrasonic irradiation may be performed at a frequency of about 28 to 100 kHz.

In order to obtain the fine particles of the present invention, for example, the polyamic acid fine particles obtained by the above method are used as the component (C), and the component layer is formed on the components (A) and (B) (however, (D). The tetracarboxylic acid anhydride (A) and the diamine compound (B) used in the reaction are different from each other) and precipitated on the component (C), thereby having a three-layer polyamic acid. Fine particles can be obtained. By repeating the same operation, fine particles having a desired multilayer can be obtained. For example, when preparing fine particles having an n layer (n is an integer of 2 or more) polyamic acid and / or a polyimide layer on the component (C), an n-1 layer polyamic acid and a polyamic acid on the component (C) / Or fine particles having a polyimide layer may be used as seed fine particles. In addition, as the component (C), polyamic acid may be used as it is, but it is also possible to use a polyimide fine particle which is once subjected to a ring-closing reaction.

The particle diameter of the polymer fine particles obtained is the particle diameter of the component (C) consisting of the (D) component or the multilayer structure particles having (n-1) layers, ((A) component + (B) component) / ( C) It can be controlled by adjusting the ratio of the components. For example, in the case of producing larger fine particles while keeping the ratio of ((A) component + (B) component) / (C) component constant, the particle size of the (C) component may be increased. In order to produce larger fine particles using the component (C) having the same particle diameter, the ratio of ((A) component + (B) component) / (C) component may be increased. Usually, the average particle diameter is preferably about 0.2 to 800 μm.

In addition, since the particle size distribution of the component (C) is reflected in the particle size distribution of the polymer fine particles obtained, the conventional method can be achieved by using the component (D) having a uniform particle size manufactured by a known method. Thus, it is possible to easily produce fine particles having a uniform particle size and a large particle size.

  The reaction between the component (A) and the component (B) is not particularly limited and may be performed under known conditions. Usually, the reaction is performed at about -10 ° C to 50 ° C because the particle diameter can be easily controlled. preferable. In particular, when the (A) component solution and the (B) component solution are mixed and supplied in advance using a micromixer, the supply rates of the (A) component solution and the (B) component solution are not particularly limited. )) And (B) may be appropriately selected depending on the reactivity of the component, but usually the ratio (mol) of (A) component / (B) component is about 0.9 to 1.1, respectively. It is preferable from the standpoint of yield and the like to set the feed rate. For example, when a solution having a concentration of 0.04 mol / liter is supplied, it may be set to about 0.5 to 100 ml / min. When the supply rate is slow, the production time is long, which is not practical. When the supply rate is too fast, formation of polyamic acid on the surface other than the component (C) may be likely to occur.

  The number average molecular weight of the polyamic acid thus obtained (polystyrene conversion value by gel permeation chromatography method) is about 2,000 to 500,000, and is selective to the (C) component and the (D) component. In order for precipitation to proceed smoothly, it is preferably about 1,000 to 50,000. In addition, since these molecular weights are caused by the reaction conditions, the molecular weights in the same layer are almost constant as long as the reaction proceeds under the same conditions.

  Specifically, for example, when polyimide fine particles made of BTDA-DPE are used as the component (D), BTDA is used as the component (A), and DA5MG is used as the component (B), BTAD-DPE / BTDA-DA5MG Polyamic acid fine particles having a two-layer structure are obtained. Further, when the polyamic acid fine particles having this two-layer structure are used as the component (C) and BTDA is used as the component (A) and DPE is used as the component (B), BTAD-DPE / BTDA-DA5MG / BTAD-DPE Thus, polyamic acid fine particles having a three-layer structure are obtained.

The resulting polyamic acid fine particles are further subjected to an imide ring-closing reaction to obtain polyimide fine particles. If the temperature is lower than the glass transition point of the polyamic acid at the time of ring closure, the surface smoothness and layer structure observed in the polyamic acid fine particles can be maintained as they are. In addition, what is necessary is just to perform the imide ring-closing reaction of polyamic acid by well-known methods, such as heating and adding a catalyst.

  Each layer thickness of the polyimide fine particles and polyamic acid fine particles obtained in this manner is usually 0.1 μm or more, and an arbitrary layer thickness can be designed. It is preferably about 4 to 4.0 μm.

In the imidization of the polyamic acid fine particles, a porosity of 5 to 50 nm can be formed between the layers of the polyimide fine particles by designing the fine particles using the difference in volume shrinkage between the layers. Specifically, for example, a polyamic acid layer having a small volume shrinkage during imidization may be introduced into the outer layer, and a polyamic acid layer having a larger volume shrinkage during imidization may be introduced into the inner layer. Examples of the composition of the polyamic acid having a small volumetric shrinkage include wholly aromatic polyamic acids such as a combination of PMDA-DPE and BTDA-DPE. Examples of the polyamic acid having a large volumetric shrinkage include butane. -1,2,3,4-tetracarboxylic dianhydride-composition using an aliphatic monomer such as DA5MG, or only one of component (A) and component (B) such as BTDA-DA5MG is fat A composition using a group-based monomer is exemplified.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Moreover, the average particle diameter and the surface roughness were determined by the following methods.
Average particle diameter: The fine particles were observed with a scanning electron microscope (SEM), 100 arbitrary fine particles were selected, the particle diameters of these fine particles were measured, and the average value was calculated and determined.
Coefficient of variation: From the average particle size value calculated by the above method,
C = [{1 / (n−1) × Σ (M−X) ² } ^1/2 / X] × 100
C: coefficient of variation, X: average particle size, M: measured particle size, n: number of samples. Thus, the coefficient of variation was determined. The larger the coefficient of variation, the greater the variation.
Surface roughness: A matrix resin in which fine particles are embedded is cut out with a microtome or the like to prepare a cross-sectional observation sample. This was observed with a transmission electron microscope (TEM), and the cross section of one particle was selected, and the cross-sectional image of the particles with the longest diameter obtained by surface observation with SEM and the error within ± 0.5% was selected. In the observed particles, the value of the shortest radius and the values of the radius of the other four concave portions and the five convex portions were measured, and the surface roughness was calculated from the following formula using the ten-point average height.
Formula:
Surface roughness (nm) = Σ {(L _H1 + L _H2 + L _H3 + L _H4 + L _H5 ) / 5- (L _L1 + L _L2 + L _L3 + L _L4 + L _L5 ) / 5} / n
The surface roughness was determined by L _Hx : radius of convex part (nm), L _Lx : radius of concave part (nm) (including the shortest radius), n: number of samples (in this example, n = 10). The smaller the value, the smoother the surface.

Production Example 1 (Manufacture of core material fine particles (D))
150 ml of an acetone solution (0.06 mol / l) of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and an acetone solution of 4,4′-diaminodiphenyl ether (DPE) (0.06 After mixing 150 ml of mol / l), the reaction was carried out at 25 ° C. for 30 minutes while irradiating 38 kHz ultrasonic waves (using an ultrasonic cleaner SONO CLEANER 100Z manufactured by Kaijo Corporation), and an acetone dispersion of polyamic acid fine particles 300 ml was obtained. The fine particles (D) contained in this dispersion were 3.5 g, the surface roughness was 8 nm, the average particle size was 0.31 μm, and the coefficient of variation was 18.2%.

Example 1
(A) 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) acetone solution (0.04 mol / l) as component solution, (A ′) component solution 3,3 ′, 4 , 4'-Benzophenonetetracarboxylic dianhydride (BTDA) as an acetone solution (0.06 mol / l), and (B) component solution as an acetone of 1,5-bis (4-aminophenoxy) alkane (DA5MG) An acetone solution (0.06 mol / l) of 4,4′-diaminodiphenyl ether (DPE) was prepared as a solution (0.04 mol / l) and (B ′) component solution. Using a micromixer (YM-1 type, manufactured by Yamatake Corporation), a reactor as shown in FIG. 2 was assembled, and polyamic acid fine particles were synthesized. Add 20 ml of the seed fine particle (D) dispersion obtained in Production Example 1 to a fine particle preparation tank with a capacity of 5000 ml with a stirrer, and stir (A) component solution and (B) component solution at 40 ml / min while stirring. And mixed through a micromixer. In addition, each solution, the line 3, the line 4, the micromixer 5, and the fine particle preparation tank 7 were kept at 5 ° C. After a total of 3000 ml of the mixed solution of the component solution (A) and the component solution (B) was flowed out, a switching valve was used to replace the component solution (A) and the component solution (A ′) instead of the component solution (A) and (B). , (B ′) component solutions were mixed and fed through a micromixer at a flow rate of 30 ml / min. When the liquid composition was switched, the extraction valve was opened while continuing the liquid supply, and 2300 mL of the dispersion liquid was extracted. Thereafter, the solution is continuously fed, the reaction is carried out while flowing out a total of 3300 ml of the mixed solution of the component solution (A ′) and the component solution (B ′), and the resulting fine particles are filtered, washed with acetone, and then dried. As a result, 48.2 g (yield 46.1%) of polyamic acid fine particles having a three-layer structure with a surface roughness of 3 nm, an average particle diameter of 2.19 μm, and a coefficient of variation of 29.7% were obtained. A SEM photograph is shown in FIG.

Example 2
10.0 g of the polyamic acid fine particles having a three-layer structure obtained in Example 1 are dispersed in tetralin, heated, and reacted for 4 hours under reflux, with a surface roughness of 8 nm, an average particle size of 1.93 μm, and a coefficient of variation. 9.5 g (yield 95.0%) of polyimide fine particles having a 35.0% three-layer structure was obtained. An SEM photograph is shown in FIG. The obtained do IR measurement of the particle, the amide group absorption band of 1550 cm ^-1 had ^disappeared, 1720 cm -1, 1380 cm ^-1, and imidization from the appearance of the absorption bands of imide group-specific 720 cm ^-1 Further, it was confirmed in the cross-sectional TEM photograph shown in FIG. 5 that the fine particles have a layer structure and the formation of a porosity of about 10 nm on average between the layers.

Comparative Example 1
3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) in acetone (0.002 mol / l), 2,4,6-triaminopyrimidine (TAPM) and 4,4 A mixed acetone solution of '-diaminodiphenyl ether (DPE) (0.002 mol / l TAPM: DPE molar ratio is 1: 4) was prepared, respectively. At 25 ° C., 100 ml of an acetone solution of BTDA and a mixed acetone of TAPM and DPE 100 ml of the solution was mixed and reacted with ultrasonic waves of 38 kHz (using a ultrasonic cleaning machine SONO CLEANER 100Z manufactured by Kaijo Co., Ltd.) at 25 ° C. for 30 minutes to obtain 200 ml of an acetone dispersion of polyamic acid fine particles. . Thereafter, the precipitate was collected by filtration and washed with acetone 3 times and xylene 3 times to obtain polyamic acid fine particles having a functional group on the surface (yield 46.0%). The recovered polyamic acid fine particles (0.3 g) were dispersed in 200 ml xylene, and then imidized by refluxing for 4 hours. The imidized fine particles were collected by filtration and then washed with xylene three times to obtain 229 mg (yield 76.3%) of polyimide fine particles having a functional group on the surface with an average particle size of 520 nm and a coefficient of variation of 17.8%. It was. 100 mg of the above polyimide fine particles were dispersed in 10 ml of dimethylformamide (DMF), 644 mg of BTDA was added and stirred for 1 hour, and then a solution of 400 mg of DPE dissolved in 10 ml of DMF was added and stirred for 24 hours. After completion of the reaction, the fine particles were collected by filtration. The physically adsorbed polyamic acid was washed with DMF three times, and then washed with xylene three times to obtain polyimide fine particles having a surface coated with a polyamic acid film 112.9 mg ( Yield 9.9%). 90.0 mg of the fine particles were dispersed in a mixed solvent of 20 ml of DMF and 2 ml of toluene, and refluxed for 4 hours to imidize the polyamic acid layer on the surface. After completion of the reaction, the fine particles are collected by filtration, washed with acetone 3 times and xylene 3 times, and then the solvent is distilled off by vacuum drying. The surface roughness is 52 nm, the average particle diameter is 500 nm, and the coefficient of variation is 18.5%. 76.0 mg of the layer-structured polyimide fine particles (yield 88.4% was obtained. The SEM photograph is shown in FIG. 6.

FIG. 1 is a cross-sectional view of a fine particle model for explaining the surface roughness of the fine particles. FIG. 2 is a conceptual diagram of a polymer fine particle manufacturing apparatus. FIG. 3 is a scanning electron micrograph of the polymer fine particles obtained in Example 1. FIG. 4 is a scanning electron micrograph of the polymer fine particles obtained in Example 2. FIG. 5 is a transmission electron micrograph of the polymer fine particle cross section obtained in Example 2. FIG. 6 is a scanning electron micrograph of the polymer fine particles obtained in Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tetracarboxylic acid anhydride (A) solution supply means 2 Diamine compound (B) solution supply means 3 Tetracarboxylic acid anhydride (A) solution supply line 4 Diamine compound (B) solution supply line 5 Micromixer 6 Mixture discharge Line 7 Fine particle preparation tank 8 Liquid feed switching valve 9 Tetracarboxylic acid anhydride (A ′) solution supply means 10 Diamine compound (B ′) solution supply means 11 Tetracarboxylic acid anhydride (A ′) solution supply line 12 Diamine Compound (B ′) solution supply line 13 Tank liquid extraction valve 14 Tank liquid extraction line

Claims (10)

Polyamic acid or polyimide fine particles having a smooth surface having at least two polyamic acid layers and / or polyimide layers in the outer layer of the core fine particles (D) and having a surface roughness of less than 20 nm. A polyamic acid or polyimide fine particle in which the polyamic acid layer and / or the polyimide layer provided on the outer layer of the core fine particles (D) has a thickness of 0.1 to 400 μm. The polyamic acid or polyimide fine particles according to claim 1 or 2, wherein the average particle diameter is 0.2 to 800 µm. The polyamic acid or polyimide fine particle according to any one of claims 1 to 3, wherein the polyamic acid and / or polyimide forming the polyamic acid layer and / or the polyimide layer has a number average molecular weight of 1,000 to 500,000. Polyimide fine particles having a porosity of 5 to 50 nm between polyimide layers. The tetracarboxylic acid anhydride (A) and the diamine compound (B) are mixed and reacted in the presence of the core material fine particles (D) and precipitated on the core material fine particles (D). After forming a polyamic acid layer to form seed fine particles (C), the tetracarboxylic acid anhydride (A) and the diamine compound (B) (however, the tetralayer used when the component layer was formed on (D)) A polyamic acid layer characterized in that a carboxylic acid anhydride (A) and a diamine compound (B) are mixed and reacted to form a polyamic acid layer on the seed fine particles (C). Production method. The method for producing fine polyamic acid particles according to claim 6, wherein the tetracarboxylic acid anhydride (A) and the diamine compound (B) are mixed and reacted after forming a tetracarboxylic acid anhydride solution and a diamine compound solution. The method for producing fine polyamic acid particles according to any one of claims 6 to 7, wherein the mixture is reacted at -10 ° C to 50 ° C. The method for producing fine polyamic acid particles according to any one of claims 6 to 8, wherein the seed fine particles (C) have a particle size of 0.2 to 800 µm. A method for producing polyimide fine particles, comprising imidizing the polyamic acid fine particles obtained by the method according to any one of claims 6 to 9 at a temperature not higher than a glass transition point of a constituent component.

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