JP5288681B2 - Ultrafine silica dispersion, ultrafine silica dispersion, and production method thereof - Google Patents

Description

  The present invention relates to an ultrafine silica dispersion, an ultrafine silica dispersion, and methods for producing them.

  In recent years, a kind of so-called nanocomposite, in which ultrafine silica is highly dispersed in a synthetic resin or the like, has been attracting attention mainly for electronics-related materials, and there is an increasing interest in those with better cost performance.

  To date, dispersions of ultrafine silica into a monomer or initial polymer for producing a synthetic resin are (1) a sol-gel process from a silica compound in the monomer or initial polymer for producing a synthetic resin. (2) produced by a method of dispersing ultrafine silica synthesized from a silica compound by a sol-gel method in a monomer or an initial polymer for producing a synthetic resin. (Non-Patent Document 1).

However, the dispersions obtained by these methods have the following drawbacks.
(i) The dispersion obtained by the above method contains impurities derived from raw materials, catalysts, by-products and the like, and cannot be used for applications requiring high purity such as electronics-related materials.
(ii) The dispersion obtained by the above method has insufficient dispersibility of the ultrafine silica, and the silica is likely to be aggregated, and therefore cannot be a nanocomposite or a raw material for producing the nanocomposite.
(iii) Since the raw materials used in the above method are expensive and the manufacturing process is complicated, the production efficiency is extremely poor.

In addition, attempts have been made to directly disperse high-purity ultrafine silica in a solvent or a monomer or an initial polymer for the production of a synthetic resin. However, the high-purity ultrafine silica is very easily aggregated because silanol groups on the surface of the single particle are easily hydrogen-bonded. Therefore, a dispersion in which the high-purity ultrafine silica is directly dispersed in a solvent, and A dispersion obtained by directly dispersing high-purity ultrafine silica in a monomer or initial polymer for producing a synthetic resin has extremely poor long-term stability (Non-Patent Document 2).
New aspects of organic / inorganic nanocomposites, publisher NTS Inc., publisher Takashi Yoshida, publication date November 1, 2004, pp. 16-17 Basics of kneading / dispersing and advanced applied technology, Techno System Co., Ltd., Publisher: Takashi Nakajima, Date of issue: November 30, 2003, page 439

  An object of the present invention is to provide an ultrafine silica dispersion and dispersion in which ultrafine silica is highly dispersed, and a method for producing them.

  The inventor has conducted extensive research to develop an ultrafine silica dispersion in which ultrafine silica is highly dispersed. As a result, it has been found that a desired ultrafine silica dispersion can be obtained by mixing ultrafine silica with a specific solvent and treating the resulting mixture under specific conditions. Furthermore, the present inventor can obtain a desired ultrafine silica dispersion by mixing the monomer or the initial polymer for producing a synthetic resin with the ultrafine silica dispersion obtained and then removing the solvent. I found out. The present invention has been completed based on such findings.

The present invention provides dispersions, dispersions, and production methods thereof shown in the following 1-4.
1. An ultrafine silica dispersion having a transparent or organosol-like appearance, in which ultrafine silica is dispersed in a solvent containing a hydroxyl group-containing solvent as a main component.
2. A method for producing an ultrafine silica dispersion having a transparent or organosol appearance, wherein ultrafine silica is dispersed in a solvent containing a hydroxyl group-containing solvent as a main component,
A method for producing an ultrafine silica dispersion, comprising mixing a solvent containing a hydroxyl group-containing solvent as a main component and ultrafine silica, and vigorously stirring the resulting mixture, or treating the mixture with ultrasonic waves. .
3. An ultrafine silica dispersion having a transparent or translucent appearance, wherein ultrafine silica is dispersed in a monomer or an initial polymer for producing a synthetic resin.
4). A method of producing an ultrafine silica dispersion having a transparent or translucent appearance, wherein ultrafine silica is dispersed in a monomer or initial polymer for production of a synthetic resin,
(A) A solvent containing a hydroxyl group-containing solvent as a main component and ultrafine silica are mixed, and the resulting mixture is vigorously stirred, or the mixture is treated with ultrasonic waves to produce an ultrafine silica dispersion. Process,
(B) a step of mixing the ultrafine silica dispersion obtained in the step (a) with a monomer or an initial polymer for producing a synthetic resin, and (c) from the mixture obtained in the step (b). A method for producing an ultrafine silica dispersion, comprising a step of removing a solvent.

Ultrafine silica dispersion The ultrafine silica dispersion of the present invention is a mixture of a solvent containing a hydroxyl group-containing solvent as a main component and ultrafine silica, and the resulting mixture is vigorously stirred or the mixture is treated with ultrasonic waves. It is manufactured by doing.

  In this specification, “violently stirring” means, for example, stirring with a φ50 mm four-blade stirrer with a rotation speed of 1000 rpm or more and a stirring time of 30 minutes or more.

  The ultrafine silica used in the present invention is known, and specifically, ultrafine anhydrous silica (fumed silica) obtained by hydrolyzing a silicon compound in a flame of oxygen and hydrogen.

  The maximum particle size of the ultrafine silica is usually 300 nm or less, preferably 100 nm or less, more preferably 50 nm or less.

  The particle diameter of the ultrafine silica can be determined from, for example, a transmission electron microscope (TEM) photograph.

  As the hydroxyl group-containing solvent, a known organic solvent can be widely used as long as it has a hydroxyl group and has a boiling point of about 200 ° C. or less. Examples of such solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol monomethyl ether, and ethylene glycol monoethyl. Examples include alcohols such as ether. Of these solvents, ethyl alcohol and isopropyl alcohol are preferred.

  The solvent for dispersing the ultrafine silica is a solvent mainly composed of the above hydroxyl group-containing solvent. The ratio of the hydroxyl group-containing solvent is usually 50% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more in the total solvent.

  As the solvent other than the hydroxyl group-containing solvent, a known hydrophobic organic solvent can be used as long as the compatibility with the hydroxyl group-containing solvent is good and the boiling point is about 200 ° C. or less.

  Examples of such a hydrophobic organic solvent include aromatic hydrocarbon solvents such as benzene, toluene and xylene, and ketone solvents such as methyl ethyl ketone.

  By using a mixed solvent of a hydroxyl group-containing solvent and a hydrophobic organic solvent, a better ultrafine silica dispersion can be obtained.

  The mixing ratio of the solvent containing the hydroxyl group-containing solvent as a main component and the ultrafine silica is not particularly limited, but the ultrafine silica is usually 1 to 70% by weight, preferably 5 to 60% with respect to the solvent. It is desirable to mix both so that it may become weight%, More preferably, it will be 10 to 50 weight%.

  The mixture of solvent and ultrafine silica is vigorously stirred or sonicated.

  Stirring is preferably performed after adjusting the pH value of the mixture to the acidic range. The pH value of the mixture is more preferably about 3 to 5, and particularly preferably about 3 to 4.

  In order to adjust the pH value of the mixed solution to the acidic range, for example, benzenesulfonic acid, p-toluenesulfonic acid, oxalic acid, citric acid and the like can be mentioned.

  The conditions of the ultrasonic treatment are, for example, that the output is usually about 100 to 2000 W, the oscillation frequency is usually about 20 to 100 KHz, and the ultrasonic treatment time is suitably 1 minute or longer.

  It is desirable that the pH of the mixture is in the acidic range when sonicating.

  As described above, in the ultrafine silica dispersion of the present invention, ultrafine silica is dispersed in a solvent containing a hydroxyl group-containing solvent as a main component, and the appearance is transparent or in an organosol state. This ultrafine silica dispersion is extremely excellent in stability, and precipitation due to aggregation of ultrafine silica is not substantially observed even when left for a long time (for example, 6 months).

Ultrafine silica dispersion The ultrafine silica dispersion is obtained by mixing the ultrafine silica dispersion obtained above with a monomer or an initial polymer for synthetic resin production, and then removing the solvent from the resulting mixture. Thus, it is easily manufactured.

  Examples of the monomer for producing the synthetic resin include acrylic monomers, styrene, α-methylstyrene, divinylbenzene, maleic anhydride, itaconic acid, and the like. Of these, acrylic monomers are preferred.

  Specific examples of the acrylic monomer include acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, allyl acrylate, Hexyl acrylate, 2-ethylhexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate, phenyl acrylate, benzyl acrylate, 2-hydroxyethyl acrylate, acrylic 2-hydroxypropyl acid, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, diethylene glycol ethoxyl acrylate, diacrylic acid Acid ethylene glycol, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexamethylene glycol diacrylate, diacrylic acid Diglycidyl bisphenol A, trimethylolpropane triacrylate, pentaerythritol triacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl Tert-butyl acid, allyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, heptyl methacrylate, methacrylic acid Butyl, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, stearyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate , Glycidyl methacrylate, tetrahydrofurfuryl methacrylate, diethylene glycol ethoxyl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate , 1,4-butylene glycol dimethacrylate, 1,6-hexamethylene glycol dimethacrylate, dimeta Examples include diglycidyl bisphenol A crylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, acrylonitrile, acrylamide, and N-methylolacrylamide.

  Among these acrylic monomers, acrylic acid, methacrylic acid, methyl methacrylate and 2-hydroxyethyl methacrylate are particularly preferable.

  Examples of the initial polymer for producing the synthetic resin include an epoxy resin initial condensate and a phenol resin initial condensate.

  Specific examples of the epoxy resin initial condensate include bisphenol A type epoxy resin initial condensate (for example, bisphenol A diglycidyl ether), bisphenol F type epoxy resin initial condensate, xylenol type epoxy resin initial condensate, and brominated bisphenol A. Type epoxy resin initial condensate, phenol novolac type epoxy resin initial condensate, brominated phenol novolac type epoxy resin initial condensate, glycidyl ester type epoxy resin initial condensate, glycidylamine type epoxy resin initial condensate, alicyclic epoxy resin An initial condensate, an aliphatic type epoxy resin initial condensate (for example, neopentyl glycol diglycidyl ether) and the like can be mentioned.

  Specific examples of the phenol resin initial condensate include a novolac type phenol resin initial condensate and a resol type phenol resin initial condensate.

  Among these initial condensates, a novolac type phenol resin initial condensate is preferable.

  The number average molecular weight of the initial polymer is usually about 200 to 2000, preferably about 300 to 1200.

  The mixing ratio of the ultrafine silica dispersion and the monomer or initial polymer for producing the synthetic resin is not particularly limited and can be appropriately selected from a wide range. For example, it is good to mix both so that the said ultrafine particle silica may be about 1 to 70 weight% normally with respect to the said monomer or initial stage polymer, Preferably it is about 5 to 50 weight%.

  The mixing means is not particularly limited, and known mixing means can be widely used.

  In removing the solvent from the mixture, there is no particular limitation, and known solvent removing means can be widely used. For example, the solvent may be evaporated by heating, or the solvent may be evaporated under reduced pressure. The solvent removed from the mixture by evaporation can be recovered using a known recovery device and reused.

  As described above, in the ultrafine silica dispersion of the present invention, the ultrafine silica is uniformly dispersed in the monomer or initial polymer for producing the synthetic resin, and the appearance is transparent or translucent. This ultrafine silica dispersion is extremely excellent in stability, and precipitation due to aggregation of ultrafine silica is not substantially observed even when left for a long period (for example, 6 months).

  According to the present invention, an ultrafine silica dispersion in which ultrafine silica is highly dispersed in a solvent is provided.

  In the ultrafine silica dispersion of the present invention, high purity ultrafine silica is uniformly dispersed in a solvent and is excellent in stability. A desirable dispersion state can be maintained throughout.

  According to the present invention, there is provided an ultrafine silica dispersion in which ultrafine silica is highly dispersed in a monomer or an initial polymer for producing a synthetic resin.

  In the ultrafine silica dispersion of the present invention, the ultrafine silica of high purity is uniformly dispersed in the monomer or the initial polymer, and the superfine silica is agglomerated because of excellent stability. The desired dispersion state can be maintained over a long period of time.

  In the ultrafine silica dispersion of the present invention and the ultrafine silica dispersion of the present invention, since the ultrafine silica used is high purity ultrafine silica, impurities caused by raw materials, catalysts, by-products, etc. It is not contained at all, and therefore can be suitably used for applications requiring high purity such as electronics-related materials.

  In addition, as described above, the ultrafine silica dispersion of the present invention and the ultrafine silica dispersion of the present invention are excellent in dispersibility and hardly cause aggregation of silica, so that they can be used without any problem in the nanocomposite or its production raw material. be able to.

  Furthermore, the production method of the ultrafine silica dispersion of the present invention and the ultrafine silica dispersion of the present invention is easy to obtain and inexpensive, and the production process is simple. Very good in terms of efficiency.

  The present invention will be further clarified by the following examples and comparative examples.

Example 1
450 g of ethanol is put into a 1 liter beaker and stirred at 300 rpm with a stirrer with φ50 mm 4 blades (in-house assembly). 50 g of OX50 (manufactured by Nippon Aerosil Co., Ltd.) was added little by little to obtain a mixed solution.

  Next, the mouth portion of the beaker is covered with aluminum foil, and this beaker is placed in a water tank of an ultrasonic cleaning machine (trade name: UT604, manufactured by Sharp Corporation), and the height of the liquid mixture and the liquid level in the beaker. After pouring tap water into the water tank until the two coincided, ultrasonic waves were generated at maximum output for 60 minutes to produce an ultrafine silica dispersion.

Example 2
An ultrafine silica dispersion was produced in the same manner as in Example 1 except that 450 g of n-butanol was used instead of ethanol.

Comparative Example 1
An ultrafine silica dispersion was produced in the same manner as in Example 1 except that 450 g of methyl ethyl ketone was used instead of ethanol.

Comparative Example 2
An ultrafine silica dispersion was produced in the same manner as in Example 1 except that 450 g of ethyl acetate was used instead of ethanol.

Example 3
450 g of ethanol is put into a 1 liter beaker, and it is stirred at 300 rpm with a stirrer with Φ50 mm 4 blades (in-house assembly). 50 g of OX50 (manufactured by Nippon Aerosil Co., Ltd.) was added little by little to obtain a mixed solution.

  Next, the part of the mouth other than the stirring bar was covered with aluminum foil, the rotation speed of the stirrer was further increased to 1500 rpm, and stirring was continued at 1500 rpm for 60 minutes to produce an ultrafine silica dispersion.

Comparative Example 3
450 g of ethanol is put into a 1 liter beaker and stirred at 300 rpm with a stirrer with φ50 mm 4 blades (in-house assembly). 50 g of OX50 (manufactured by Nippon Aerosil Co., Ltd.) was added little by little to obtain a mixed solution.

  Next, the mouth portion other than the stirring bar was covered with aluminum foil, and stirring was further continued for 60 minutes at a rotation speed of 300 rpm of the stirrer to produce an ultrafine silica dispersion.

Example 4
An ultrafine silica dispersion was produced in the same manner as in Example 1 except that a mixed solution of 300 g of ethanol and 150 g of methyl ethyl ketone was used instead of ethanol.

Example 5
An ultrafine silica dispersion was produced in the same manner as in Example 1 except that a mixed solution (pH about 3 to 4) of 300 g of ethanol, 150 g of methyl ethyl ketone and 0.05 g of benzenesulfonic acid was used instead of ethanol.

  The appearance of each of the ultrafine silica dispersions obtained in Examples 1 to 5 and Comparative Examples 1 and 2 was visually observed, and the B-type viscometer rotor No. 1 (manufactured by Tokyo Keiki Co., Ltd.) was used to measure the viscosity (cps) at 25 ° C.

  The results are shown in the following table.

Example 6
In a 100 ml beaker, 10.0 g of the dispersion obtained in Example 1 and 9.0 g of neopentyl glycol diglycidyl ether were thoroughly stirred with a glass rod and mixed.

  Next, the beaker is placed in a 100 ° C. oil bath, the contents are vigorously stirred with a glass rod, and the solvent is evaporated until there is no foaming or solvent odor, thereby dispersing ultrafine silica in neopentyl glycol diglycidyl ether. A dispersion was produced.

Comparative Example 4
An ultrafine silica dispersion was produced in the same manner as in Example 6 except that the dispersion obtained in Comparative Example 1 was used instead of the dispersion obtained in Example 1.

Comparative Example 5
An ultrafine silica dispersion was produced in the same manner as in Example 6 except that the dispersion obtained in Comparative Example 3 was used instead of the dispersion obtained in Example 1.

Example 7
An ultrafine silica dispersion was produced in the same manner as in Example 6 except that the dispersion obtained in Example 5 was used instead of the dispersion obtained in Example 1.

Example 8
In a 100 ml beaker, 10.0 g of the dispersion obtained in Example 5 and 9.0 g of bisphenol A diglycidyl ether were thoroughly stirred with a glass rod and mixed. Thereafter, an ultrafine silica dispersion was produced in the same manner as in Example 6.

Example 9
In a 100 ml beaker, 10.0 g of the dispersion obtained in Example 5 and 9.0 g of phenol novolak resin (trade name: Phenolite TD-2131, manufactured by Dainippon Ink & Chemicals, hydroxyl equivalent 103) Stir well with a glass rod and mix. Thereafter, an ultrafine silica dispersion was produced in the same manner as in Example 6.

Example 10
In a 100 ml beaker, 10.0 g of the dispersion obtained in Example 5 and 9.0 g of 2-hydroxyethyl methacrylate were well stirred with a glass rod and mixed. Thereafter, an ultrafine silica dispersion was produced in the same manner as in Example 6.

  The appearance of each ultrafine silica dispersion obtained in Examples 6 to 10 and Comparative Example 4 was visually observed, and the B-type viscometer rotor No. Viscosity (cps) at 25 ° C. was measured using 3 (manufactured by Tokyo Keiki Co., Ltd.) (only rotor of Example 8 was rotor No. 6 (manufactured by Tokyo Keiki Co., Ltd.)).

  The results are shown in the following table.

Claims (3)

An ultrafine silica dispersion in which the appearance is transparent or in an organosol state, wherein the ultrafine silica is dispersed in a mixed solvent of a hydroxyl group-containing organic solvent and a ketone solvent,
The proportion of the hydroxyl group-containing organic solvent in the mixed solvent is 50% by weight or more.
Ultrafine silica dispersion. An ultrafine silica dispersion having a transparent or organosol-like appearance, in which ultrafine silica is dispersed in a mixed solvent of a hydroxyl group-containing organic solvent and a ketone solvent, and the hydroxyl group-containing organic solvent in the mixed solvent The proportion of is 50% by weight or more,
A method for producing an ultrafine silica dispersion,
An ultrafine particle silica dispersion comprising a step of mixing a mixed solvent of a hydroxyl group-containing organic solvent and a ketone solvent and ultrafine particle silica and vigorously stirring the resulting mixture or treating the mixture with ultrasonic waves. Manufacturing method. A method of producing an ultrafine silica dispersion having a transparent or translucent appearance, wherein ultrafine silica is dispersed in a monomer or initial polymer for production of a synthetic resin,
(A) Mixing a mixed solvent of a hydroxyl group-containing organic solvent and a ketone solvent containing a hydroxyl group-containing organic solvent in a proportion of 50% by weight and ultrafine silica, and stirring the resulting mixture vigorously, A step of producing an ultrafine silica dispersion by treating the mixture with ultrasound,
(B) the step of mixing the ultrafine silica dispersion obtained in the step (a) with a monomer or an initial polymer for the production of a synthetic resin, and (c) the mixture obtained in the step (b). A method for producing an ultrafine silica dispersion, comprising a step of removing the mixed solvent.