JP6084448B2 - Method for producing black filler - Google Patents

Description

The present invention relates to a process for the production of black filler over.

  For example, black particles are used as spacers for liquid crystal display devices (see Patent Documents 1 and 2). Patent Document 1 discloses black-based particles obtained by heat-treating particles obtained by particle growth using a metal alkoxide decomposition product. Patent Document 2 discloses black silica particles obtained by heating after contacting a fluorinating agent and an organic solvent with silica particles.

Japanese Patent Publication No. 07-82172 Japanese Patent Laid-Open No. 03-279209

  By the way, for example, when a display device such as a liquid crystal display device is narrowed, light emitted from the backlight easily leaks to the front side through a seal portion in the frame. As the narrowing of the display device is expected to progress further, the filler blended in the matrix constituting the seal portion is also required to have excellent blackness in order to suppress light leakage. It will be.

An object of the present invention is to provide a method for producing easily black filler over that to exert blackness.

Method for producing a black-filler for solving the above problems is a method for producing a black-filler obtained by organopolysiloxane and a vinyl polymer from the powder of the composite composite particles, wherein the organopolysiloxane is represented by the following general formula (1):
R ¹ Si (OR ² ) ₃ (1)
(In the general formula (1), R ¹ is a non-hydrolyzable group and has an alkyl group having 1 to 20 carbon atoms, a (meth) acryloyloxy group, or an epoxy group having 1 to 20 carbon atoms, An alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms; R ² represents an alkyl group having 1 to 6 carbon atoms; and each OR ² is identical to each other. Or a different condensate obtained from a trialkoxysilane, and the vinyl polymer contains a vinyl polymer having a nitrile group and constitutes the black filler. particles, wherein comprises a carbon of organic components in the composite particles produced by carbonizing a coloring material state, and are Y value of 6% or less in the XYZ color system, said manufacturing method, the tri alkoxysilane A composite step of forming the composite particle by polymerizing the monomer after the vinyl monomer having a nitrile group is absorbed in the particle containing the condensate obtained from orchid, and an organic component in the composite particle A carbonization step for carbonizing .

In the black filler manufacturing method , the vinyl polymer having a nitrile group includes a vinyl polymer containing acrylonitrile as a constituent unit, and the black particles have a mass ratio of acrylonitrile to the trialkoxysilane of 0.2. It is preferably obtained from the composite particles in the range of ˜3. Here, the said mass ratio is a value calculated | required from each mass of trialkoxysilane used as a raw material of a black filler, and acrylonitrile.

  According to the present invention, it is easy to exhibit blackness.

Hereinafter, embodiments of the black filler and the manufacturing method thereof will be described.
<Black filler>
The black filler is obtained from a powder of composite particles in which an organopolysiloxane and a vinyl polymer are combined. The organopolysiloxane contains a condensate obtained from trialkoxysilane represented by the following general formula (1).

R ¹ Si (OR ² ) ₃ (1)
In the general formula (1), R ¹ is a non-hydrolyzable group, an alkyl group having 1 to 20 carbon atoms, (meth) acrylic alkyl group having 1 to 20 carbon atoms having acryloyloxy group or epoxy group, the carbon number R ² represents an alkyl group having 1 to 6 carbon atoms, R ² represents an alkyl group having 1 to 6 carbon atoms, and each OR ² is the same as each other. It may or may not be.

  Examples of trialkoxysilanes represented by the general formula (1) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and propyltriethoxysilane. , Butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-acryloyloxypropyltrimethoxysilane, and γ-methacryloyloxy And propyltrimethoxysilane.

The trialkoxysilane represented by the general formula (1) can be used alone or in combination of two or more.
The organopolysiloxane may contain a condensate obtained from at least one organoalkoxysilane selected from dialkoxysilane and monoalkoxysilane.

  The vinyl polymer includes a vinyl polymer having a nitrile group. Examples of the vinyl polymer having a nitrile group include those containing at least one of acrylonitrile and methacrylonitrile as a structural unit. The structural unit of the vinyl polymer having a nitrile group may include, for example, methyl acrylate, vinyl acetate, methyl methacrylate, and the like.

  The vinyl polymer having a nitrile group preferably contains a vinyl polymer containing acrylonitrile as a constituent unit, and more preferably contains 50 mol% or more of acrylonitrile.

  The black particles constituting the black filler are preferably obtained from composite particles in which the mass ratio of acrylonitrile to trialkoxysilane is in the range of 0.2 to 3. When the mass ratio of acrylonitrile to trialkoxysilane is 0.2 or more, the blackness is more likely to increase. When the mass ratio of acrylonitrile to trialkoxysilane is 3 or less, aggregation of black particles is easily suppressed and sphericity of the black particles is easily increased. When the mass ratio is 3 or less, the insulating properties of the black particles are likely to increase.

The black particles contain carbon generated by carbonizing the organic component in the composite particles as a colored substance. The organic component comprises the general formula R ¹ (1), and a vinyl polymer described above. Carbonization of the organic component is performed by heating the powder of the composite particles.

  The Y value of the black filler in the XYZ color system is 6% or less. The Y value in the XYZ color system is a value measured in accordance with JIS Z8701: 1999. The Y value is preferably 5% or less from the viewpoint of exhibiting more blackness.

The average particle size of the black filler is preferably 0.1-2. The particle size distribution of the black filler is indicated by the following CV value (coefficient of variation).
CV value (%) = {standard deviation of particle diameter [μm] / average particle diameter [μm]} × 100
The CV value of the black filler is preferably 20% or less. Depending on the application, a black filler having a wide particle size distribution may be desired. In this case, for example, the particle size distribution can be adjusted by changing manufacturing conditions such as catalyst addition conditions. The particle size distribution may be adjusted by mixing two or more black fillers having different average particle sizes or particle size distributions.

  The sphericity of the black particles constituting the black filler is preferably 0.8 or more. The sphericity indicates an average value of 50 black particles. The sphericity of each black particle is determined by the following formula.

Sphericality = short diameter of black particles / long diameter of black particles The black filler can be used, for example, in an application for enhancing the shielding property of the seal portion by being blended in a matrix constituting the seal portion of the display device. Examples of the matrix include an epoxy resin and an epoxy acrylic resin. The black filler is, for example, a core material for conductive particles, an additive for a coating film, an additive for a light diffusion film, an unevenness imparting agent, an additive for cosmetics, an additive for paint or ink, an adhesive. It can also be used as an additive and various fillers.

<Black filler production method>
Next, the manufacturing method of a black filler is demonstrated. The manufacturing method of a black filler includes a composite process and a carbonization process. In the composite step, the vinyl monomer having a nitrile group is absorbed into particles containing a trialkoxysilane condensate. Further, in the composite process, composite particles are formed by polymerizing a vinyl monomer having a nitrile group.

Particles containing a trialkoxysilane condensate are obtained through a seed particle formation step and a growth particle formation step.
(Seed particle formation process)
In the seed particle forming step, the organoalkoxysilane is hydrolyzed and condensed by adding a catalyst to a solution in which an organoalkoxysilane containing at least trialkoxysilane is dissolved in an aqueous solvent. Thereby, seed particles containing a condensate of trialkoxysilane are formed. In the seed particle forming step, an aqueous seed particle dispersion medium in which the seed particles are dispersed in the aqueous dispersion medium as droplets is obtained.

  Examples of the aqueous solvent include a mixed solvent of water and a water-miscible organic solvent, or water. Examples of the water-miscible organic solvent include lower alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, dimethyl ketone and methyl ethyl ketone, and ethers such as diethyl ether and dipropyl ether. One or a combination of two or more water-miscible organic solvents can be used.

  The aqueous solvent can contain a stabilizer from the viewpoint of enhancing the solubility of the organoalkoxysilane and stabilizing the generated seed particles. Examples of the stabilizer include a surfactant and a polymer dispersant. When it is desired to reduce the ionic substance remaining in the black particles, it is preferable to use a nonionic stabilizer.

  Examples of the catalyst include at least one of ammonia and amine. Examples of the amine include monomethylamine, dimethylamine, monoethylamine, diethylamine and ethylenediamine. A catalyst can be used 1 type or in combination of 2 or more types. Among the catalysts, ammonia is preferable from the viewpoint of low toxicity, easy removal from the particles, and low cost.

  The hydrolysis and condensation reaction is carried out while stirring the organoalkoxysilane and the catalyst in an aqueous solvent. The catalyst amount at the start of the reaction can be set according to a conventional method. The amount of catalyst at the start of the reaction can be set according to, for example, the type and concentration of the organoalkoxysilane and the particle size of the resulting particles. Although reaction temperature is suitably set according to the kind of organoalkoxysilane, the range of 0-50 degreeC is suitable, for example.

The average particle size of the seed particles in the aqueous seed particle dispersion is appropriately set according to the average particle size of the black filler to be produced, but is preferably 0.05 to 1.9 μm.
(Composite process)
In the composite step, first, an emulsion containing a monomer having a nitrile group is prepared. A vinyl monomer having a nitrile group is dispersed in an aqueous dispersion medium together with an emulsifier according to a conventional method, whereby an emulsion in which the monomer is dispersed as oil droplets is obtained. As the aqueous dispersion medium, those exemplified as the aqueous dispersion medium used in the seed particle forming step can be used.

The content of the vinyl monomer having a nitrile group in the emulsion is, for example, 10 to 70% by mass.
The emulsifier can be appropriately selected and used, for example, using the HLB value (hydrophilic / lipophilic balance value) as an index. As the emulsifier, for example, an alkyl sulfate having an alkyl group having 6 to 30 carbon atoms is preferably used. Examples of the alkyl sulfate salt include potassium salt, sodium salt, ammonium salt and the like. As an emulsifier, it is also possible to use a polyoxyethylene nonionic surfactant.

  The emulsion further contains a radical polymerization initiator. The type of radical polymerization initiator is not particularly limited, and examples thereof include azo polymerization initiators such as azobisisobutyronitrile and peroxides such as benzoyl peroxide. The content of the radical polymerization initiator in the emulsion is preferably in the range of 0.001 to 20 mol, more preferably 0.01 to 10 mol, with respect to 1 mol of the monomer.

The emulsion may contain a vinyl monomer other than the monomer having a nitrile group.
The prepared emulsion is mixed with an aqueous seed particle dispersion. In the obtained mixed liquid, the vinyl monomer is absorbed by the seed particles. Then, the vinyl monomer is radically polymerized by heating the mixed solution. Thereby, solid composite particles are formed. Mixing of the emulsion and the seed particle aqueous dispersion is preferably performed before the condensation reaction of the seed particles is completed. The mixing of the emulsion and the seed particle aqueous dispersion is preferably performed within a range of 1 minute or more and 10 minutes or less from the addition of the catalyst in the seed particle formation step. By mixing within 10 minutes from the addition of the catalyst, the vinyl monomer is more easily absorbed into the seed particles. In the composite process, composite particles are obtained by washing and separating the composite particles.

(Carbonization process)
In the carbonization step, the organic component in the composite particles is carbonized by heating the powder of the composite particles. The carbonization step is preferably performed in a gas having a lower oxygen concentration than air. Examples of the gas having a lower oxygen concentration than air include an inert gas and a reducing gas. Examples of the inert gas include nitrogen gas, helium gas, neon gas, and argon gas. As reducing gas, ammonia gas is mentioned, for example. In the carbonization step, a mixed gas mixed with at least one selected from an inert gas and a reducing gas and air may be used, or only at least one selected from an inert gas and a reducing gas may be used.

  The heating temperature in the carbonization step is, for example, 350 to 1000 ° C. The heating time in the carbonization step is, for example, 2 to 48 hours. In the carbonization step, the blackness of the black filler can also be controlled by changing the heating conditions. For example, by increasing the heating temperature, the blackness of the black filler increases and the hardness tends to increase.

<Operation of black filler and method for producing the same>
The vinyl polymer in the composite particle includes a vinyl polymer having a nitrile group. When carbon derived from a vinyl polymer having a nitrile group is included in the black particles as a coloring substance, a black filler with high blackness is easily obtained.

According to the embodiment described in detail above, the following effects are exhibited.
(1) The composite particles include a condensate obtained from trialkoxysilane represented by the general formula (1) and a vinyl polymer having a nitrile group. The black particles constituting the black filler contain carbon generated by carbonizing the organic component in the composite particles as a coloring substance. The Y value of the black filler in the XYZ color system is 6% or less. According to the black filler comprised in this way, it becomes easy to exhibit blackness.

  (2) The black particles constituting the black filler are preferably obtained from composite particles in which the mass ratio of acrylonitrile to trialkoxysilane is in the range of 0.2 to 3. In this case, it becomes easy to ensure the blackness and hardness of the black filler.

  (3) The manufacturing method of a black filler has a composite process and a carbonization process. In the composite step, particles containing a trialkoxysilane condensate are absorbed with a vinyl monomer having a nitrile group, and then the vinyl monomer is polymerized to form composite particles. In the carbonization step, the organic component in the composite particles is carbonized. According to this manufacturing method, it becomes easy to exhibit blackness.

(4) The black filler of this embodiment can be suitably used in the electronic field and the semiconductor field where a high-purity filler is required.
(5) Sealing materials for electronic parts that are becoming smaller or thinner are required to maintain fluidity and moldability even when they are highly filled. Thus, in order to maintain the fluidity and moldability of the sealing material, it is preferable that the filler is spherical, has an appropriate particle size distribution, and has good dispersibility. In the method for producing a black filler of the present embodiment, high sphericity is obtained and the particle size distribution is easily adjusted, and a black filler with good dispersibility can be easily obtained.

  (6) The black filler of this embodiment has a small variation in outer shape. For this reason, in the composite material in which the black filler is filled in the resin material, the increase in the viscosity of the composite material is suppressed more than in the case where the amorphous filler such as metal powder or carbon black is filled. Moreover, since the black filler of this embodiment contains a silica, the effect which the fall of the linear expansion coefficient of a composite material is suppressed and the effect which maintains insulation are anticipated.

The embodiment may be modified as follows.
-Seed particles grown larger can be obtained by repeating the seed particle formation step a plurality of times.

-After the seed particle formation step, a growth particle formation step of growing seed particles using organoalkoxysilane may be performed.
-Surface treatment may be given to black particles. For example, the insulating properties of the black particles can be improved by coating the surface of the black particles with an insulating material. For example, when black particles are mixed with a resin material, the dispersibility of the black particles in the resin can be improved by subjecting the black particles to a surface treatment using a material having a high affinity with the resin material.

The technical idea that can be grasped from the above embodiment will be described below.
(A) In the black filler, the average particle diameter is 0.1 to 2 μm, the CV value is 5% or less, and the black particles constituting the black filler have a sphericity of 0.8 or more. Filler.

  (B) In the method for producing a black filler, the absorption in the composite step is an aqueous dispersion of particles containing an emulsion containing a vinyl monomer having the nitrile group and a condensate obtained from the trialkoxysilane. The manufacturing method of the black filler performed by mixing.

Next, examples and comparative examples will be described.
Example 1
<Preparation of seed particles>
After stirring 360 g of vinyltrimethoxysilane (VTMS) and 3600 g of water for 1 hour at 25 ° C., 36 g of 1% sodium dodecyl sulfate aqueous solution and 73 g of 1N-ammonia aqueous solution were added, and the mixture was further stirred for 5 minutes. A polysiloxane dispersion of particles was obtained.

<Preparation of monomer emulsion>
A mixed liquid was prepared by dissolving 10 g of azobisisobutyronitrile (AIBN) as a polymerization initiator in 180 g of acrylonitrile. By stirring this mixed solution and a solution prepared by dissolving 17 g of a sulfate ester salt (trade name: New Coal 707SF, Nippon Emulsifier Co., Ltd.) with 500 g of ion-exchanged water as an emulsifier at 20000 rpm for 1 minute using a homogenizer, A body emulsion was prepared.

<Composite of vinyl polymer>
After adding the monomer emulsion to the organopolysiloxane dispersion and stirring for 1 hour, in order to perform radical polymerization of the monomer, a dispersion of composite particles was prepared by holding at 70 ° C. for 6 hours.

  After cooling this dispersion, decantation using isopropyl alcohol as the cleaning liquid was repeated three times to wash the composite particles. After removing isopropyl alcohol from the supernatant, the composite particles were dried in an oven at 80 ° C. for 1 hour to obtain composite powder. The obtained powder was white.

<Carbonization of organic components>
The composite particle powder was heated at 680 ° C. for 160 minutes in a nitrogen atmosphere. By this heating, a black filler was obtained by carbonizing the organic component contained in the composite particles.

(Example 2)
In Example 2, a black filler was prepared in the same manner as in Example 1, except that the seed particle preparation conditions and the monomer emulsion preparation method were changed. In Example 2, 102 g of vinyltrimethoxysilane (VTMS) and 375 g of water were stirred at 25 ° C. for 1 hour, and then added to a mixed solution of 912 g of water, 12 g of 10% ammonium dodecyl ammonium sulfate solution and 3 g of 25% ammonia aqueous solution. The mixture was further stirred for 5 minutes to obtain a dispersion of VTMS seed particles.

  In the preparation of the monomer emulsion, first, a mixed solution was prepared by dissolving 8 g of azobisisobutyronitrile (AIBN) as a polymerization initiator in 77 g of acrylonitrile. By stirring this mixed solution and a solution obtained by dissolving 2.5 g of a sulfate ester salt (trade name: New Coal 707SF, Nippon Emulsifier Co., Ltd.) as an emulsifier with 77 g of ion-exchanged water at 20000 rpm for 1 minute, A monomer emulsion was prepared.

(Example 3)
In Example 3, a black filler was prepared in the same manner as in Example 1 except that the heating temperature was changed to 1000 ° C. in carbonization of the organic component.

Example 4
In Example 4, a black filler was prepared in the same manner as in Example 1 except that the amount of acrylonitrile was changed to 90 g in the preparation of the monomer emulsion.

(Example 5)
In Example 5, a black filler was prepared in the same manner as in Example 1 except that the seed particle preparation conditions were changed. In Example 5, 500 g of methyltrimethoxysilane (MTMS) and 5000 g of water were stirred at 30 ° C. for 1 hour, and then a mixed solution of 15 g of 1% sodium dodecyl sulfate aqueous solution and 50 g of 1N ammonia aqueous solution was added. By stirring for 5 minutes, a dispersion of MTMS seed particles was obtained.

(Comparative Example 1)
In Comparative Example 1, the vinyl polymer composite was omitted, and the organopolysiloxane dispersion was washed and dried in the same manner as the composite particle dispersion in Example 1 to obtain organopolysiloxane particle powder. It was. The obtained powder of organopolysiloxane particles was heated at 650 ° C. for 160 minutes in a nitrogen atmosphere. A black filler was obtained by carbonizing the organic component contained in the organopolysiloxane particles by this heating.

(Measurement of Y value)
The Y value in the XYZ color system of the black powder of each example was measured according to JIS Z8701: 1999. First, a quartz powder holder was set in a spectrophotometer (V-670, manufactured by JASCO Corporation), and zero point correction was performed. Next, black powder was put in the powder holder, and the Y value was measured. The Y value of the powder of Comparative Example 1 was similarly measured. The results are shown in Table 1.

(Average particle size and CV value)
In each example, each of the seed particle dispersion, the composite particle powder, and the black filler was sampled, and the average particle size was measured using a laser diffraction particle size distribution analyzer (trade name: Mastersizer, manufactured by Spectris Co., Ltd.). Asked. Moreover, the particle diameter was measured about 50 black particles from the image which observed the black filler of each Example with the scanning microscope. The CV value was calculated | required using the value. For Comparative Example 1, the average particle size and the CV value were similarly determined. The results are shown in Table 1.

(Measurement of sphericity)
Using the image obtained by observing the black filler of each example with a scanning electron microscope, the major axis and minor axis of 50 black particles were measured. The sphericity was determined using the value. For Comparative Example 1, the sphericity was similarly determined. The results are shown in Table 1.

As shown in Table 1, in the black filler of each Example, the Y value was 6% or less. In Comparative Example 1, since the black filler was obtained without compounding the vinyl polymer, the Y value of the black filler exceeded 6%.

Claims (2)

A method for producing a black filler obtained from a powder of composite particles obtained by combining an organopolysiloxane and a vinyl polymer,
The organopolysiloxane has the following general formula (1):
R ¹ Si (OR ² ) ₃ (1)
(In the general formula (1), R ¹ is a non-hydrolyzable group and has an alkyl group having 1 to 20 carbon atoms, a (meth) acryloyloxy group, or an epoxy group having 1 to 20 carbon atoms, carbon An alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms; R ² represents an alkyl group having 1 to 6 carbon atoms; and each OR ² is identical to each other. Or different.)
A condensate obtained from a trialkoxysilane represented by
The vinyl polymer includes a vinyl polymer having a nitrile group,
The black particles constituting the black filler, the comprises a carbon of organic components in the composite particles produced by carbonizing a coloring material state, and are Y value of 6% or less in the XYZ color system,
The manufacturing method includes a composite step of forming the composite particles by polymerizing the monomer after the vinyl monomer having a nitrile group is absorbed into the particles containing the condensate obtained from the trialkoxysilane. ,
Method for producing a black filler; and a carbonization step of carbonizing the organic component in the composite particles. The vinyl polymer having a nitrile group includes a vinyl polymer containing acrylonitrile as a constituent unit,
The said black particle is a manufacturing method of the black filler of Claim 1 obtained from the composite particle by which the mass ratio of the acrylonitrile with respect to the said trialkoxysilane was made into the range of 0.2-3.