JP2012240900A - Spherical silica powder, slurry using the same and resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin cured material which has extremely high flowability when being highly filled into a resin and in which spherical silica powder is properly dispersed by using the spherical silica powder having a particular particle size and a particular isolated silanol group.SOLUTION: The spherical silica powder satisfies following conditions: (α) the particle size distribution has two frequency maximum values A (μm) and B (μm) wherein the frequency maximum value A has a range of 0.40-1.5 μm and the maximum value B has a range of 0.03-0.07 μm, and the volume frequency value of A is 3.0-7.0% and the volume frequency value of B is 1.0-9.0%; and (β) the spherical silica powder having a particle size of less than 0.1 μm is 5-30 mass% and the concentration of the isolated silanol (isolated OH) group of the powder is less than 1.0/nm. It is preferable that the cumulative volume 10% value is 0.04-0.1 μm and the cumulative 90% value is 1.4-2.0 μm.

Description

The present invention relates to spherical silica powder.

In recent years, with the increase in speed, size, weight, and functionality of electronic devices, printed wiring boards that support high-density mounting and wiring miniaturization have been developed. In a multilayer printed wiring board with a high density, problems such as cracking due to the difference in thermal expansion coefficient between the insulating layer and the copper wiring or IC chip, heat resistance during manufacturing, etc. are likely to occur. There is a demand for improvement in thermal characteristics such as a low coefficient of thermal expansion. In response to this requirement, a method of highly filling an inorganic filler such as silica in a matrix resin such as an epoxy resin, or a method using a rigid resin is known. However, when the filler is highly filled in the resin, the fluidity and moldability are significantly reduced. Therefore, in the nano to submicron region, improvement of fluidity and moldability by close packing using fillers having different particle size distributions has been proposed.

For example, in Patent Document 1, a slurry in which spherical silica particles having an average particle size of 0.1 μm to 5 μm and a sphericity of 0.8 or more and silica nanoparticles having an average particle size of 1 nm to 50 nm are dispersed in an organic solvent. Compositions and varnish compositions are disclosed. In this case, the fluidity decreases due to the blending of fumed silica that is arranged in a bead shape and the epoxy resin is poorly cured due to the residual silanol groups of the sol-gel silica. Not reached. In Patent Document 2, the silica powder has an average particle diameter D50 of 2.0 μm or less, a 100% equivalent diameter D100 of 5.0 μm or less, and a silica ultrafine powder that does not substantially form a structure structure contains a silane compound. A high-concentration silica slurry is disclosed that is dispersed in an organic solvent by 20% by volume or more. However, the fluidity improvement effect was not obtained only by the definition of D50 and D100.

JP 2006-36916 A JP 2003-54935 A

The present invention has been made in view of the above, and by using a spherical silica powder having a specific particle size distribution and a specific isolated silanol group, the fluidity of the resin composition is extremely high when the resin is highly filled. And it aims at providing the resin hardened | cured material which spherical silica powder disperses | distributes favorably.

The present invention employs the following means in order to solve the above problems.
(1) A spherical silica powder characterized by satisfying the following conditions.
(Α) The particle size distribution has two frequency maximum values A (μm) and B (μm), the frequency maximum value A is 0.40 to 1.5 μm, and the frequency maximum value B is 0.03 to 0.07 μm. The volume frequency value of A is 3.0 to 7.0%, and the volume frequency value of B is 1.0 to 9.0%.
(Β) The spherical silica powder of less than 0.1 μm is 5 to 30% by mass, and the concentration of isolated silanol (isolated OH) groups in the powder is less than 1.0 / nm ² .
(2) The spherical silica powder according to (1), wherein the cumulative volume 10% value is 0.04 to 0.1 μm and the cumulative volume 90% value is 1.4 to 2.0 μm.
(3) The spherical silica powder according to (1) or (2), wherein the spherical silica powder of 0.1 to 4.0 μm is 70 to 95% by mass.
(4) A slurry comprising the spherical silica powder according to any one of (1) to (3) and a solvent.
(5) A resin composition using the slurry according to (4).

By using spherical silica powder having a specific particle size distribution and specific isolated silanol groups, the resin composition has extremely high fluidity when the resin is highly filled, and the spherical silica powder is well dispersed. Things can be provided.

The present invention is a spherical silica powder characterized by satisfying the following conditions.
(Α) The particle size distribution has two frequency maximum values A (μm) and B (μm), the frequency maximum value A is 0.40 to 1.5 μm, and the frequency maximum value B is 0.03 to 0.07 μm. The volume frequency value of A is 3.0 to 7.0%, and the volume frequency value of B is 1.0 to 9.0%.
(Β) The spherical silica powder of less than 0.1 μm is 5 to 30% by mass, and the concentration of isolated silanol (isolated OH) groups in the powder is less than 1.0 / nm ² .

The frequency maximum value A of the spherical silica powder is 0.40 to 1.5 μm. If it exceeds 1.5 μm, silica agglomerates may be generated and the appearance may be deteriorated, and if it is less than 0.4 μm, it is high. Fluidity may not be obtained. A preferred range is 0.6 to 1.3 μm. The frequency maximum value B is 0.030 to 0.070 μm, and if it exceeds 0.070 μm, the high fluidity that appears with the close-packed formation may be impaired, and it is less than 0.030 to 0.070 μm. If it exists, the dispersion system becomes unstable as the specific surface area increases, so that the particles aggregate to impair fluidity. A preferred range is 0.040 to 0.060 μm.
When the volume frequency value of A exceeds 7.0%, when the volume frequency value of B is less than 1.0%, high fluidity associated with an increase in the maximum filling rate of silica cannot be obtained. In addition, when the volume frequency value of A is less than 3.0%, and when the volume frequency value of B exceeds 9.0%, the dispersion system becomes unstable as the specific surface area increases. Flocculates and fluidity is impaired. A preferable range of the volume frequency value of A is 4.0 to 6.0%, and a preferable range of the volume frequency value of B is 2.0 to 6.0%.
The content of the spherical silica powder of less than 0.1 μm is 5 to 30% by mass, preferably 8 to 20% by mass, from the viewpoints of fluidity and dispersibility. The concentration of isolated silanol (isolated OH) groups present in the spherical silica powder of less than 0.1 μm is less than 1.0 / nm ² . When the concentration of isolated silanol (isolated OH) groups present in the spherical silica powder of less than 0.1 μm is 1.0 / nm ² or more, the hydrophilic isolated silanol groups remaining after the surface treatment cause resin curing inhibition, There is a possibility of appearance failure. The concentration of the isolated silanol group is preferably 0.5 / nm ² or less.

  The particle size distribution, the accumulated volume 10% value, and the accumulated volume 90% value of the spherical silica powder are values based on a dynamic light scattering particle size measuring machine. For example, ("UPA-EX150" Nikkiso Co., Ltd.) Manufactured). In the measurement, the particle size distribution was analyzed by dividing the 0.003-6.5 μm diameter range into 43 parts.

The method of collecting the surface-treated spherical silica powder of 0.1 μm or less is as follows. Cellulose mixed ester type filter “2-3043-24” (manufactured by Millipore), PTFE filter “J010A025A” (manufactured by ADVANTEC), cellulose mixed ester type filter “ A membrane filter having a diameter of 0.1 μm such as “A010A025A” (manufactured by ADVANTEC) is used. Among these, a cellulose mixed ester type filter “A010A025A” (manufactured by ADVANTEC) is particularly preferable. What is necessary is just to perform the particle size distribution measurement of the collected silica powder as the confirmation method that the particle | grains of 0.1 micrometer or more do not exist.

The quantification of the isolated silanol (isolated OH) group concentration present in the spherical silica powder of less than 0.1 μm in the present invention includes acid-base titration, infrared absorption analysis (IR), nuclear magnetic resonance analysis, Karl Fischer coulometric titration method and the like. This is done by a known method. In particular, the size of an absorption peak derived from an isolated silanol group near 3740 cm ⁻¹ is measured by FT-IR (diffuse reflection method), and 0.1 μm or less from the size of the absorption peak of a standard substance having a known silanol group concentration. A method for determining the concentration of isolated silanol groups present in the powder is preferred.

Spherical silica powder of the present invention, from the viewpoint of close-packed particles, 10% cumulative volume value _{(hereinafter,} referred to as _{D 10)} is 0.04 to 0.1 [mu] m, the cumulative volume of 90% value _{(hereinafter,} referred to as _{D 90)} Is preferably in the range of 1.4 to 2.0 μm. When D ₁₀ is less than 0.04 μm, the specific surface area increases, and thus the fluidity may be deteriorated. If D ₁₀ exceeds 0.1 μm or D ₉₀ is less than 1.4 μm, the range of the particle size distribution is narrow, so that the high fluidity effect associated with close-packing may not be obtained. If D ₉₀ of greater than 2.0 .mu.m, there is a possibility that the grains due to aggregation of the silica particles in the resin cured product with a spherical silica powder (mass) occurs.

The spherical silica powder of the present invention is preferably subjected to a surface treatment. By performing the surface treatment in advance, aggregation of silica particles can be suppressed, and spherical silica powder can be favorably dispersed in the resin composition. The surface treatment can be carried out using various silane, titanate, and aluminate coupling agents, epoxy resins, silicone oils, alkylsilazanes and the like. For example, the surface treatment with the silane coupling agent may be performed by reacting the spherical silica powder with a silane coupling agent vaporized in a state where a floating layer or the like is formed in the treatment container. Surface treatment with alkylsilazanes can be carried out by reacting alkylsilazane vaporized in a state where a floating layer or the like is formed in a processing vessel with a silanol group, and surplus alkylsilazanes are volatilized by heating. Good.

  It is preferable that the amount of the silane coupling agent for surface-treating the spherical silica powder is 0.1% by mass or more and 7% by mass or less based on the total amount of the spherical silica powder and the silane coupling agent. More preferably, 0.3 mass% or more and 5 mass% or less are preferable. If the amount of silane coupling agent used exceeds the upper limit, moisture absorption may increase due to the influence of excess silane coupling agent, and if it is less than the lower limit, adhesion to the resin is impaired. May be.

The method for producing the spherical silica powder of the present invention is not particularly limited. For example, a metal powder slurry is supplied into a high-temperature flame composed of a combustible gas and an auxiliary combustion gas in a production furnace, and the metal powder is contained in the flame. It is obtained by classifying the powder produced by oxidation.

The spherical silica powder-containing slurry will be described.
The spherical silica powder can be suitably used as a slurry using water or an organic solvent. The type of the organic solvent in which the spherical silica powder is dispersed is not particularly limited. What is necessary is just to select according to resin. For example, polar solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, and ethyl acetate are used.
Of these, methyl ethyl ketone is particularly preferable.

The dispersion treatment of the spherical silica powder-containing slurry may be performed using a device such as a ball mill, an ultrasonic disperser, various mixers, or a high-pressure homogenizer. In order to prevent the slurry from being modified, it is desirable to perform the production in a non-oxidizing atmosphere such as a nitrogen atmosphere.

  Although content of the spherical silica powder contained in a slurry does not have a restriction | limiting in particular, It is preferable that it is 50-85 mass% from a viewpoint of the moldability of a resin composition.

The resin composition will be described.
When manufacturing a resin substrate such as a semiconductor package substrate or an interlayer insulating film using the silica-containing slurry, it is preferable to employ an epoxy resin as the resin.

The epoxy resin used in the resin composition is not particularly limited, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, naphthalene type epoxy resin, and phenoxy type epoxy resin. Can be mentioned. One of these can be used alone, two or more having different important molecular weights can be used in combination, and one or two or more can be used.
Among these epoxy resins, bisphenol F type epoxy resin is particularly preferable.

  Although the resin composition of this invention should just use a well-known hardening | curing agent, a phenol type hardening | curing agent can be used. As the phenolic curing agent, a phenol novolac resin, an alkylphenol novolac resin, polyvinylphenols and the like can be used alone or in combination of two or more.

  As for the compounding quantity of the said phenol hardening | curing agent, the equivalent ratio (phenolic hydroxyl group equivalent / epoxy group equivalent) with an epoxy resin is less than 1.0, and 0.1 or more are preferable. As a result, there remains no unreacted phenol curing agent, and the moisture absorption heat resistance is improved.

The amount of the spherical silica powder blended in the resin composition is desirably 80% by mass or more based on the total mass of the resin composition from the viewpoint of heat resistance and thermal expansion coefficient.

Example 1-21 Comparative Example 1-11
The spherical silica powder obtained by classifying the spherical silica powder produced by the metal powder slurry method (“SFP-30M” manufactured by Denki Kagaku Kogyo Co., Ltd.) was subjected to surface treatment to obtain a surface-treated spherical silica powder. For the surface treatment, 3-glycidoxypropyltrimethoxysilane (“KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent was used. The amount of the silane coupling agent used was 0.5% by mass with respect to the total amount of the spherical silica powder and the silane coupling agent.
Similarly, the spherical nanosilica powder obtained by classifying the spherical nanosilica powder produced by the metal powder slurry method (“UFP-30” manufactured by Denki Kagaku Kogyo Co., Ltd.) was subjected to surface treatment to be surface-modified. Spherical nanosilica powder was used. For the surface treatment, hexamethyldisilazane (“HMDS” manufactured by Shin-Etsu Chemical Co., Ltd.) as a silylating agent was used. The amount of HMDS used was 3% by mass with respect to the total amount of spherical nanosilica powder and HMDS. Subsequently, the obtained spherical silica powder and spherical nano silica powder were dispersed in methyl ethyl ketone (MEK) to prepare a slurry having a solid content concentration of 80% by mass. Their blending amounts are shown in Tables 1-3. The average sphericity of the spherical silica powder and the spherical nanosilica powder was all 0.90 or more. The average sphericity is obtained by capturing a particle image taken with a stereomicroscope (trade name “Model SMZ-10” manufactured by Nikon Corporation) into an image analyzer (trade name “MacView” manufactured by Mountech Co., Ltd.) and projecting the particles from the photograph. Measured from area (A) and perimeter (PM). If the area of a perfect circle corresponding to the perimeter (PM) is (B), the roundness of the particle is A / B, so a perfect circle having the same perimeter as the perimeter of the sample (PM) Assuming that PM = 2πr and B = πr ² , B = π × (PM / 2π) ² , and the roundness of each particle is roundness = A / B = A × 4π / (PM ² ) The roundness of 200 arbitrary particles thus obtained was determined, and the average sphericity was obtained by squaring the average value.

  Phenol novolac type epoxy resin “EPICLON N-830” (manufactured by Dainippon Ink & Chemicals, Inc., epoxy equivalent 165 g / eq) 10% by mass as an epoxy resin, novolak type phenol resin “PSM-4261” (Gunei Chemical Co., Ltd.) as a curing agent To the 100% by mass of the silica-containing slurry composition obtained by 5% by mass, hydroxyl group equivalent 106 g / eq, softening point 80 ° C., manufactured by Kogyo Co., Ltd. and 0.2% by mass of 2-ethyl-4-methylimidazole as a curing accelerator. It melt | dissolved and the resin composition (epoxy resin varnish) was prepared. This resin composition was applied to a substrate and dried at a temperature of 150 ° C. for 2 hours to remove MEK to obtain a cured resin. The fluidity and dispersibility of the obtained resin composition and the appearance of the cured resin were evaluated according to the following methods. The evaluation results are shown in Tables 1-3.

Next, spherical silica powder of less than 0.1 μm was collected by the following method. After adding 27 g of methyl ethyl ketone (MEK) to 3.0 g of spherical silica-containing slurry, dispersion treatment was performed, and the slurry was subjected to a cellulose mixed ester type membrane filter “A010A025A” having a diameter of 0.1 μm (manufactured by ADVANTEC). Particles of 0.1 μm or less were filtered off. Next, after drying the slurry after filtration, particle size distribution measurement was performed, and it was confirmed that there were no particles of 0.1 μm or more. Thereafter, the amount of carbon in the powder was measured using a C / S analyzer (manufactured by LECO).

Furthermore, the concentration of isolated silanol (isolated OH) groups present in spherical silica powder of less than 0.1 μm was used as a product name “Spectrum One” manufactured by Perkin Elmer, Inc., an infrared absorption spectrum analyzer. In the measurement method, first, a background measurement using a standard sample was performed, then a cell filled with the sample was set, and an absorption spectrum of wave number 3740 [cm ⁻¹ ] was measured 32 times.

The evaluation methods of the resin composition and the cured resin product are shown in the following (1) to (3).
(1) Flowability The viscosity of the obtained resin composition at 2 rpm (measurement temperature 25 ° C.) was measured with a B-type viscometer (manufactured by Toki Sangyo Co., Ltd .: TVB-10). At this time, 2.0 Pa · s or more was regarded as defective.
(2) The dispersible resin composition was evaluated as dispersibility by using a grind gauge having a width of 90 mm, a length of 240 mm, and a maximum depth of 100 μm in accordance with JIS-K5101.
Each code is as follows.
◎: The scale at the position where 3 streaks (linear traces) of 1 cm or more are generated is less than 3 μm. ○: The scale at the position of 3 streaks (linear traces) of 3 cm or more is less than 5 μm. The scale where the three (linear traces) are generated is 5 μm or more × 1 cm or more where the scale where the three lines (linear traces) are 10 μm or more. (3) Formability / silica particle aggregate The number of aggregates of silica particles of 10 μm or more present in an area of 1 cm ^{3 of the} cured resin product is irradiated with a fringe pattern using a surface shape inspection system KURASURF-PH (manufactured by Kurashiki Boseki Co., Ltd.), and phase difference shift is performed. As a result, surface irregularities were detected and evaluated as moldability according to the following criteria.
Each code is the following evaluation criteria.
A: No aggregate less than 10 μm ○: Less than 5 aggregates less than 10 μm ×: 5 or more aggregates greater than 10 μm

  As is clear from the comparison of the examples and comparative examples in Tables 1 to 3, when the spherical silica powder of the present invention is highly filled in an epoxy resin, a slurry having extremely high fluidity and silica particles are well dispersed. A cured product can be obtained.

The slurry and resin composition using the spherical silica powder of the present invention can be used for printed wiring boards in the field of electronic equipment such as semiconductor package substrates and interlayer insulating films.

Claims (5)

A spherical silica powder characterized by satisfying the following conditions.
(Α) The particle size distribution has two frequency maximum values A (μm) and B (μm), the frequency maximum value A is 0.40 to 1.5 μm, and the frequency maximum value B is 0.03 to 0.07 μm. The volume frequency value of A is 3.0 to 7.0%, and the volume frequency value of B is 1.0 to 9.0%.
(Β) The spherical silica powder of less than 0.1 μm is 5 to 30% by mass, and the concentration of isolated silanol (isolated OH) groups in the powder is less than 1.0 / nm ² . 2. The spherical silica powder according to claim 1, wherein the cumulative volume 10% value is 0.04 to 0.1 μm and the cumulative volume 90% value is 1.4 to 2.0 μm. The spherical silica powder according to claim 1 or 2, wherein the spherical silica powder having a size of 0.1 to 4.0 µm is 70 to 95% by mass. A slurry comprising the spherical silica powder according to any one of claims 1 to 3 and a solvent. A resin composition using the slurry according to claim 4.