JP2017141378A - Resin particle composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin particle composition which is excellent in flowability of resin particles and handleability of the resin particle composition, and suppresses sticking of the resin particle composition into a pipe when pneumatically conveyed.SOLUTION: A resin particle composition contains resin particles, lubricant particles, and silica particles having a degree of compression aggregation of 60% or more and 95% or less and a particle compression ratio of 0.20 or more and 0.40 or less.SELECTED DRAWING: None

Description

  The present invention relates to a resin particle composition.

The resin particles are applied to various uses such as a binder.
Here, for the resin particles, for example, silica particles may be used together for functionalization such as improvement of strength and fluidity of the resin particles and suppression of packing.
In particular, powder such as resin particles is often used in a transportation method (hereinafter referred to as “air transportation”) in which the powder is transported by air flowing in a pipe, and is applied to this transportation method. Therefore, improvement of the fluidity of the resin particles is important.

For example, Patent Document 1 discloses that “the surface of hydrophilic spherical silica fine particles substantially composed of SiO ₂ units obtained by hydrolysis and condensation of a tetrafunctional silane compound and / or a partial hydrolysis-condensation product thereof. R ¹ SiO _3/2 unit (wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms) and R ² ₃ SiO _1/2 unit (wherein R ² Are the same or different and are hydrophobized silica having an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms), and the average particle diameter is in the range of 0.005 to 1.0 μm, Disclosed is a “fluidizing agent for powders comprising hydrophobic spherical silica fine particles having a particle size distribution D ₉₀ / D ₁₀ of 3 or less and an average circularity of 0.8 to 1”. .

JP 2013-166667 A

  An object of the present invention is to provide a resin particle composition having resin particles, lubricant particles, and silica particles, silica particles having a compression aggregation degree of less than 60% or more than 95%, or a particle compression ratio of 0.00. Compared to the case where silica particles less than 20 or more than 0.40 are used, the resin particles are excellent in fluidity and resin particle composition handling properties under high temperature conditions. It is to provide a resin particle composition in which sticking to a pipe is suppressed.

The above problem is solved by the following means. That is,
The invention according to claim 1
Resin particles,
Lubricant particles;
Silica particles having a compression aggregation degree of 60% to 95% and a particle compression ratio of 0.20 to 0.40;
It is a resin particle composition containing.

The invention according to claim 2
2. The resin particle composition according to claim 1, wherein the content of the lubricant particles with respect to the resin particles is 0.1% by mass or more and 8% by mass or less.

The invention according to claim 3
The resin particle composition according to claim 1 or 2, wherein the silica particles have an average equivalent-circle diameter of 40 nm to 200 nm.

  The resin particle composition according to any one of claims 1 to 3, wherein the silica particles have a particle dispersity of 90% or more and 100% or less.

The invention according to claim 5
The silica particles are surface-treated with a siloxane compound having a viscosity of 1000 cSt or more and 50000 cSt or less, and the surface adhesion amount of the siloxane compound is 0.01% by mass or more and 5% by mass or less. It is a resin particle composition as described in above.
The invention according to claim 6
The resin particle composition according to claim 5, wherein the siloxane compound is silicone oil.

  According to the invention according to claim 1, in the resin particle composition having resin particles, lubricant particles, and silica particles, silica particles having a compression aggregation degree of less than 60% or more than 95%, or particle compression Compared to the case where only silica particles having a ratio of less than 0.20 or more than 0.40 are used, the resin particles are excellent in fluidity of the resin particles and handleability of the resin particle composition under high temperature conditions. There is provided a resin particle composition in which sticking to a pipe during air transportation is suppressed.

According to the invention according to claim 2, when the content of the lubricant particles with respect to the resin particles is less than 0.1% by mass or more than 8% by mass, the resin particle composition is air-fed under a high temperature condition. There is provided a resin particle composition in which adhering to a pipe is suppressed.
According to the invention of claim 3, compared to the case where only silica particles having an average equivalent circle diameter of less than 40 nm or more than 200 nm are used, the fluidity of the resin particles and the handleability of the resin particle composition are excellent under high temperature conditions. A resin particle composition is provided.
According to the claimed invention, compared to the case where only silica particles having a particle dispersity of less than 90% are used, the resin particles are excellent in fluidity under high temperature conditions, and the resin particle composition is air-fed. There is provided a resin particle composition in which adhering to a pipe is suppressed.
According to the invention according to claim 4 or 5, silica particles surface-treated with a siloxane compound having a viscosity of less than 1000 cSt or more than 50000 cSt, or the surface adhesion amount of the siloxane compound is less than 0.01% by mass or 5% by mass. Compared to the case of using silica particles that exceed, it is excellent in the fluidity of the resin particles and the handleability of the resin particle composition under high temperature conditions, and the sticking in the pipe when the resin particle composition is air-fed is suppressed. A resin particle composition is provided.

  Embodiments that are examples of the present invention will be described below.

<Resin particle composition>
The resin particle composition according to this embodiment includes resin particles, lubricant particles, silica particles having a degree of compression aggregation of 60% to 95% and a particle compression ratio of 0.20 to 0.40 (hereinafter referred to as A resin particle composition including “specific silica particles”.

Known resin particle compositions include lubricant particles as well as resin particles.
This resin particle composition exhibits lubricity due to the lubricant particles, so that when the resin particle composition is air-fed, the resin particle composition exhibits lubricity with respect to the inner wall of the pipe and suppresses sticking in the pipe. sell.
On the other hand, in order to impart fluidity to the resin particles, it is preferable to use silica particles or the like together with the resin particles.
However, in the case of general-purpose silica particles, it is necessary to use a large amount in order to obtain sufficient fluidity of the resin particles, and as a result, the silica particles themselves are likely to be difficult to handle and free from the resin particles. The agglomerates due to the silica particles formed may be difficult to handle, and the resin particles may be difficult to handle, and the handleability of the resin particle composition may be reduced.

Since the resin particle composition according to the present embodiment has a configuration including resin particles, lubricant particles, and specific silica particles, the flowability of the resin particles and the high temperature conditions (for example, at a temperature of 30 ° C.) The handleability of the resin particle composition is excellent, and further, sticking in the piping when the resin particle composition is air-fed is suppressed.
The reason for this is not clear, but it is presumed to be due to the action resulting from the characteristics of the specific silica particles described below.

  The specific silica particles are considered to exert the following effects when the degree of compression aggregation and the particle compression ratio are within the above ranges.

First, the significance of setting the compression aggregation degree of the specific silica particles to 60% or more and 95% or less will be described.
The degree of compression agglomeration is an index indicating the aggregability of silica particles and the adhesion to resin particles. This index is indicated by the degree of difficulty of unraveling the molded body when the silica particle molded body is dropped after the silica particle molded body is obtained by compressing the silica particles.
Therefore, the higher the degree of compression aggregation, the more the silica particles tend to have a stronger cohesive force (intermolecular force) and a stronger adhesive force to the resin particles. Details of the method for calculating the degree of compression aggregation will be described later.
For this reason, the specific silica particles whose compression aggregation degree is controlled to be as high as 60% or more and 95% or less improve the fluidity and dispersibility in the resin particles while improving the adhesion and aggregation properties to the resin particles. From the viewpoint of ensuring, the upper limit of the degree of compression aggregation is 95%.

Next, the significance of the particle compression ratio of the silica particles being 0.20 or more and 0.40 or less will be described.
The particle compression ratio is an index indicating the fluidity of silica particles. Specifically, the particle compression ratio is represented by a ratio between the difference between the solid apparent specific gravity and the loose apparent specific gravity of the silica particles and the solid apparent specific gravity ((hardened apparent specific gravity−loose apparent specific gravity) / solid apparent specific gravity).
Therefore, the lower the particle compression ratio, the higher the fluidity of the silica particles. Moreover, when fluidity | liquidity is high, there exists a tendency for the dispersibility to the resin particle to also increase. The details of the particle compression ratio calculation method will be described later.
For this reason, the silica particles whose particle compression ratio is controlled to be as low as 0.20 or more and 0.40 or less have good fluidity and dispersibility in resin particles. However, the lower limit of the particle compression ratio is set to 0.20 from the viewpoint of improving the adhesion and cohesiveness to the resin particles while improving the fluidity and the dispersibility in the resin particles.

From the above, the specific silica particles have unique properties that they are easy to flow and easily disperse in the resin particles, and further have high cohesion and adhesion to the resin particles.
Therefore, the specific silica particles whose compression aggregation degree and particle compression ratio satisfy the above ranges have high fluidity and dispersibility in the resin particles, and also have the properties of high aggregation and adhesion to the resin particles. It becomes.

Next, the presumed action when specific silica particles are used in a resin particle composition having resin particles and lubricant particles will be described.
First, since the specific silica particles have high fluidity and dispersibility in the resin particles, when mixed with the resin particles, the specific silica particles easily adhere to the surface of the resin particles in a nearly uniform state. And since the specific silica particle once adhered to the surface of the resin particle has high adhesion to the resin particle, movement on the surface of the resin particle and release from the resin particle are difficult to occur. In particular, the specific silica particles once adhered to the surface of the resin particles are less likely to move on the surface of the resin particles and be released from the resin particles at a load level due to air flow when the resin particle composition is air-fed. Conceivable.
As described above, the specific silica particles easily adhere to the surface of the resin particles in a nearly uniform state, and this attached state is easily maintained. As the specific silica particles are adhered, the lubricant particles are less likely to be unevenly distributed on the surface of the resin particles and are likely to adhere in a nearly uniform state.
As a result, it is considered that the lubricity of the lubricant particles to the inner wall of the pipe is efficiently expressed, and the resin particle composition can be prevented from sticking to the pipe.

In the resin particle composition having resin particles and lubricant particles, it is difficult to obtain sufficient fluidity of the resin particles.
As described above, the specific silica particles easily adhere to the surface of the resin particles in a uniform state, and the adhesion state is easily maintained, and the fluidity of the specific particles is increased due to the material. Particles. Therefore, when specific silica particles are used in a resin particle composition having resin particles and lubricant particles, the specific silica particles adhere efficiently to the surface of the resin particles without using a large amount of the specific silica particles, and the fluidity of the resin particles is increased. It is thought that.
Further, the specific silica particles have a high cohesive property as described above. Therefore, when specific silica particles are used in a resin particle composition having resin particles and lubricant particles, the silica particles liberated from the resin particles dance due to the agglomeration property of the specific silica particles, and the silica liberated from the resin particles. It is considered that it is easy to suppress the formation of aggregates between particles and further the resin particles from dancing. Therefore, the resin particle composition according to the present embodiment is excellent in handleability (also referred to as handling property).

  In the resin particle composition according to the present embodiment, the specific silica particles preferably further have a particle dispersity of 90% or more and 100% or less.

Here, the significance of the particle dispersion degree of the specific silica particles being 90% or more and 100% or less will be described.
The degree of particle dispersion is an index indicating the dispersibility of silica particles. This index is indicated by the degree of ease of dispersion of the silica particles into the resin particles in the primary particle state. Specifically, the grain dispersity, a computational coverage of a silica particle to the resin particles and C _0, when the coverage of the actual measurement was C, and the coverage rate C of the measured to the resin particles, calculated on the It is indicated by a ratio to the coverage C ₀ (actual coverage C / calculated coverage C ₀ ).
Therefore, the higher the degree of particle dispersion, the more difficult the silica particles are to aggregate, indicating that the silica particles are easily dispersed in the state of primary particles. Details of the method for calculating the degree of particle dispersion will be described later.

  The specific silica particles are further improved in dispersibility in the resin particles by controlling the particle dispersity as high as 90% or more and 100% or less while controlling the compression aggregation degree and the particle compression ratio within the above ranges. Thereby, the lubricant particles in the resin particle composition are more likely to adhere to the surface of the resin particles in a more nearly uniform state. As a result, in the resin particle composition according to the present embodiment, the lubricity with respect to the inner wall of the pipe is efficiently expressed, and it is easy to suppress sticking of the resin particle composition into the pipe.

In the resin particle composition according to the present embodiment, as described above, the specific silica particles having properties such as high fluidity and dispersibility to the resin particles, and high cohesiveness and adhesion to the resin particles. For example, silica particles having a siloxane compound having a relatively large weight average molecular weight attached to the surface are suitable. Specific examples of the specific silica particles include silica particles in which a siloxane compound having a viscosity of 1000 cSt or more and 50000 cSt or less adheres to the surface. In particular, the surface adhesion amount of a siloxane compound having a viscosity of 1000 cSt or more and 50000 cSt or less is preferably 0.01% by mass or more and 5% by mass or less.
Here, the surface adhesion amount refers to the ratio of the mass of the siloxane compound adhering to the surface to the silica particles not adhering to the surface (also referred to as untreated silica particles).
Hereinafter, silica particles having no siloxane compound attached to the surface (untreated silica particles) are also simply referred to as “silica particles”.

A siloxane compound having a viscosity of 1000 cSt or more and 50000 cSt or less adheres to the surface, and the specific silica particles in which the surface adhesion amount of the siloxane compound is 0.01% by mass or more and 5% by mass or less have fluidity and dispersibility in resin particles. Further, the cohesiveness and the adhesion to the resin particles are also increased, and the degree of compression aggregation and the particle compression ratio easily satisfy the above requirements.
The reason for this is not clear, but is thought to be due to the following actions.

When a small amount of a siloxane compound having a relatively high viscosity within the above range is adhered to the surface of the silica particles within the above range, a function derived from the characteristics of the siloxane compound on the surface of the silica particles is exhibited. Although the mechanism is not clear, when specific silica particles are flowing, a small amount of siloxane compound having a relatively high viscosity adheres in the above range, so that releasability derived from the siloxane compound is easily developed. Or, the adhesion (aggregation property) between the specific silica particles is reduced by reducing the interparticle force due to the steric hindrance of the siloxane compound. Thereby, the fluidity | liquidity of the specific silica particle and the dispersibility to the resin particle increase.
On the other hand, when an external stress is applied to the specific silica particles, the long molecular chains of the siloxane compound on the surface of the specific silica particles are entangled, and the close packing property of the specific silica particles is increased, and the cohesive force between the specific silica particles is increased. Becomes stronger. And it is thought that the cohesion force of the silica particles due to the entanglement of long molecular chains of the siloxane compound is released when the specific silica particles are flowed. In addition to this, it is considered that the adhesion force to the resin particles is enhanced by the long molecular chain of the siloxane compound on the surface of the specific silica particles.

  From the above, the specific silica particles obtained by adhering a small amount of the siloxane compound having a viscosity in the above range to the surface of the silica particles in the above range can easily satisfy the above requirements in terms of the compression aggregation degree and the particle compression ratio, and the particle dispersion degree is also the above Easier to meet requirements.

Hereinafter, the structure of the resin particle composition will be described.
First, the specific silica particles will be described.

[Specific silica particles]
The specific silica particles have a degree of compression aggregation of 60% to 95% and a particle compression ratio of 0.20 to 0.40.
First, the characteristics of silica particles will be described in detail.

-Compression cohesion-
The compression aggregation degree of the specific silica particles is 60% or more and 95% or less from the viewpoint of ensuring fluidity and dispersibility in the resin particles while improving the cohesion and adhesion to the resin particles in the specific silica particles. From the viewpoint of pipe transportability, it is preferably 65% or more and 95% or less, more preferably 70% or more and 95% or less.

The degree of compression aggregation is calculated by the following method.
6.0 g of specific silica particles are filled into a disk-shaped (disk-shaped) mold having a diameter of 6 cm. Subsequently, the mold was compressed for 60 seconds at a pressure of 5.0 t / cm ² using a compression molding machine (manufactured by Maekawa Test Machine Manufacturing Co., Ltd.), and a compacted disc-shaped molded product of specific silica particles (hereinafter referred to as “before falling”). To be obtained). Thereafter, the mass of the molded body before dropping is measured.
Next, the molded product before dropping is placed on a sieve screen having an opening of 600 μm, and the molded product before dropping is 1 mm in amplitude and 1 minute in vibration time using a vibration sieve machine (manufactured by Tsutsui Rika Kikai Co., Ltd .: Part No. VIBRATING MVB-1). Drop under the conditions of Thereby, the specific silica particle falls from the molded body before dropping through the sieve mesh, and the molded body of the specific silica particle remains on the sieve mesh. Thereafter, the mass of the remaining molded body of specific silica particles (hereinafter referred to as “the molded body after dropping”) is measured.
Then, the degree of compression aggregation is calculated from the mass of the molded body after dropping and the mass of the molded body before dropping using the following formula (1).
Formula (1): Compression cohesion degree = (mass of molded product after dropping / mass of molded product before dropping) × 100

-Particle compression ratio-
The particle compression ratio of the specific silica particles is 0.20 or more and 0.40 from the viewpoint of ensuring cohesion and adhesion to the resin particles while improving the fluidity and dispersibility of the specific silica particles in the resin particles. From the viewpoint of pipe transportability, it is preferably 0.28 or more and 0.38 or less, more preferably 0.28 or more and 0.36 or less.

The particle compression ratio is calculated by the following method.
Using a powder tester (manufactured by Hosokawa Micron Corporation, product number PT-S type), the loose apparent specific gravity and the solid apparent specific gravity of the specific silica particles are measured.
Then, using the following formula (2), the particle compression ratio is calculated from the difference between the apparent apparent density and the loose apparent specific gravity of the silica particles and the apparent apparent specific gravity.
Formula (2): Particle compression ratio = (Fixed apparent specific gravity−Loose apparent specific gravity) / Folded apparent specific gravity

The “sloppy apparent specific gravity” is a measured value derived by filling a specific silica particle into a container having a capacity of 100 cm ³ and weighing it, and filling the specific silica particle in a state of being naturally dropped into the container. Specific gravity. “Fixed apparent specific gravity” means that the specific silica particles are degassed by applying impact (tapping) 180 times repeatedly at a stroke length of 18 mm and a tapping speed of 50 times / minute from the state of loose apparent specific gravity. Apparent specific gravity, rearranged and packed more closely.

-Particle dispersity-
The particle dispersion degree of the specific silica particles is preferably 90% or more and 100% or less, more preferably 95% or more and 100% or less, and still more preferably 100, from the viewpoint of further improving dispersibility in the resin particles. %.

The particle dispersity is a ratio between the actually measured coverage C on the resin particles and the calculated coverage C _0, and is calculated using the following equation (3).
Formula (3): degree of particle dispersion = measured coverage C / calculated coverage C ₀

Here, the calculated coverage C ₀ on the surface of the resin particles with the specific silica particles is the volume average particle diameter of the resin particles dt (m), the average equivalent circle diameter of the specific silica particles da (m), the resin When the specific gravity of the particles is ρt, the specific gravity of the specific silica particles is ρa, the weight of the resin particles is Wt (kg), and the addition amount of the specific silica particles is Wa (kg), the following formula (3-1) is used. Can do.
Formula (3-1): Calculation coverage ratio C ₀ = √3 / (2π) × (ρt / ρa) × (dt / da) × (Wa / Wt) × 100 (%)

  The actual coverage C on the surface of the resin particles with the specific silica particles is determined using an X-ray photoelectron spectrometer (XPS) ("JPS-9000MX": manufactured by JEOL Ltd.), only the resin particles, only the specific silica particles, And about the resin particle containing specific silica particle, the signal intensity | strength of the silicon atom originating in a specific silica particle can be measured, respectively, and it can calculate with a following formula (3-2).

Formula (3-2): Actual coverage C = (z−x) / (y−x) × 100 (%)
[In formula (3-2), x represents the signal intensity of a silicon atom derived from specific silica particles only of resin particles. y shows the signal intensity of the silicon atom derived from the specific silica particle only of the specific silica particle. z shows the signal intensity of the silicon atom derived from the specific silica particle about the resin particle which the specific silica particle adhered (coated). ]

-Average equivalent circle diameter-
The average equivalent circle diameter of the specific silica particles can be appropriately determined according to the particle size of the resin particles, but the flowability, dispersibility to the resin particles, cohesiveness, and adhesion to the resin particles in the specific silica particles From the viewpoint of improving the property, it is preferably 40 nm or more and 200 nm or less, more preferably 50 nm or more and 180 nm or less, and further preferably 60 nm or more and 160 nm or less.

  The average equivalent circle diameter D50 of the specific silica particles is determined by using a scanning electron microscope SEM (Scanning Electron Microscope) apparatus (manufactured by Hitachi, Ltd .: S-4100) after dispersing the specific silica particles in the resin particles. Take an image by observing the image, import this image into an image analyzer (LUZEXIII, manufactured by Nireco Corporation), measure the area of each particle by image analysis of primary particles, and calculate the equivalent circle diameter from this area value To do. The 50% diameter (D50) in the cumulative frequency of the obtained equivalent circle diameter on a volume basis is defined as the average equivalent circle diameter D50 of the specific silica particles. In the electron microscope, the magnification is adjusted so that about 10 to 50 specific silica particles are captured in one field of view, and the equivalent circle diameter of the primary particles is obtained by observing a plurality of fields of view.

-Average circularity-
The shape of the specific silica particles may be either spherical or irregular, but the average circularity of the specific silica particles is the fluidity, dispersibility to resin particles, cohesiveness, and resin in the specific silica particles. From the viewpoint of improving the adhesion to the particles, it is preferably from 0.85 to 0.98, more preferably from 0.90 to 0.98, and still more preferably from 0.93 to 0.98.

The average circularity of the specific silica particles is measured by the method shown below.
First, the circularity of the specific silica particles is determined by observing the primary particles after the silica particles are adhered to the surface of the resin particles with an SEM device, and analyzing the obtained primary particles by planar image analysis according to the following formula (4). It is obtained as “100 / SF2” to be calculated.
Formula (4): Circularity (100 / SF2) = 4π × (A / I ² )
[In Formula (4), I represents the perimeter of the primary particles on the image, and A represents the projected area of the primary particles.
The average circularity of the specific silica particles is obtained as 50% circularity in the cumulative frequency of 100 primary particles obtained by the planar image analysis.

Here, a method for measuring each characteristic (compression aggregation, particle compression ratio, particle dispersion, average circularity) of the specific silica particles from the resin particle composition will be described.
First, resin particles, lubricant particles, and specific silica particles are separated from the resin particle composition as follows.
That is, the resin particle composition is put in methanol and dispersed, and after stirring, the specific silica particles having a large diameter are peeled off from the surface of the resin particle composition by treatment with an ultrasonic bath, and then the resin particles are separated by centrifugation. Only the methanol in which the specific silica particles are dispersed by collecting the composition is recovered, and then the specific silica particles can be taken out by volatilizing the methanol.
And each said characteristic is measured using the isolate | separated specific silica particle.

  Next, the configuration of the specific silica particles will be described.

-Silica particles-
The specific silica particles are particles mainly composed of silica (that is, SiO ₂ ), and may be crystalline or amorphous. The specific silica particles may be particles produced using a silicon compound such as water glass or alkoxysilane as a raw material, or may be particles obtained by pulverizing quartz.
As specific silica particles, specifically, silica particles produced by a sol-gel method (hereinafter “sol-gel silica particles”), aqueous colloidal silica particles, alcoholic silica particles, fumed silica particles obtained by a gas phase method, spherical silica Examples thereof include sol-gel silica particles.

The specific silica particles whose compression aggregation degree, particle compression ratio, and particle dispersion degree are in the specific ranges are preferably specific silica particles having a siloxane compound attached to the surface.
In order to obtain specific silica particles having a siloxane compound adhered to the surface, surface treatment with a siloxane compound is preferably used. In particular, supercritical carbon dioxide is used, and the surface of silica particles is surfaced in supercritical carbon dioxide. It is preferable to process. The surface treatment method will be described later.

-Siloxane compound-
The siloxane compound is not particularly limited as long as it has a siloxane skeleton in the molecular structure.
Examples of the siloxane compound include silicone oil and silicone resin. Among these, silicone oil is preferable from the viewpoint of adhering to the surface of the silica particles in a nearly uniform state.

Examples of the silicone oil include dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, carbinol-modified silicone oil, methacryl-modified silicone oil, and mercapto-modified. Examples include silicone oil, phenol-modified silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, alkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, higher fatty acid amide-modified silicone oil, and fluorine-modified silicone oil. Of these, dimethyl silicone oil, methyl hydrogen silicone oil, and amino-modified silicone oil are preferable.
The said siloxane compound may be used individually by 1 type, and may be used together 2 or more types.

-Viscosity-
The viscosity (kinematic viscosity) of the siloxane compound is preferably 1000 cSt or more and 50000 cSt or less from the viewpoint of improving fluidity, dispersibility to resin particles, cohesiveness, and adhesion to resin particles in the specific silica particles, and 2000 cSt. It is more preferably 30000 cSt or less, and further preferably 3000 cSt or more and 10000 cSt or less.

  The viscosity of the siloxane compound is determined by the following procedure. Toluene is added to the specific silica particles and dispersed for 30 minutes with an ultrasonic disperser. Thereafter, the supernatant is collected. At this time, a toluene solution of a siloxane compound having a concentration of 1 g / 100 ml is used. The specific viscosity [ηsp] (25 ° C.) at this time is determined by the following formula (A).

Formula (A): ηsp = (η / η0) −1
(Η0: viscosity of toluene, η: viscosity of solution)

Next, the intrinsic viscosity [η] is determined by substituting the specific viscosity [ηsp] into the relation of Huggins shown in the following formula (B).
Formula (B): ηsp = [η] + K ′ [η] ²
(K ′: Huggins constant K ′ = 0.3 (when [η] = 1 to 3 is applied))

Next, the intrinsic viscosity [η] is expressed by the following formula (C). Substituting it into the Kololov equation, the molecular weight M is determined.
Formula (C): [η] = 0.215 × 10 ⁻⁴ M ^0.65

A molecular weight M represented by the following formula (D) J. et al. The siloxane viscosity [η] is determined by substituting it into the Barry equation.
Formula (D): log η = 1.00 + 0.0123 M ^0.5

-Surface adhesion amount-
The surface adhesion amount of the siloxane compound to the surface of the specific silica particles is determined from the viewpoint of improving fluidity, dispersibility to the resin particles, cohesion, and adhesion to the resin particles in the specific silica particles. 0.01 mass% or more and 5 mass% or less are preferable with respect to the silica particle which has not adhered the compound (untreated silica particles), 0.05 mass% or more and 3 mass% or less are more preferable, 0.10 mass % To 2% by mass is more preferable.

The surface adhesion amount is measured by the following method.
Disperse 100 mg of specific silica particles in 1 mL of chloroform, add 1 μL of DMF (N, N-dimethylformamide) as an internal standard solution, and then sonicate with an ultrasonic cleaner for 30 minutes. Perform extraction. Thereafter, hydrogen nuclear spectrum measurement is performed with a JNM-AL400 type nuclear magnetic resonance apparatus (manufactured by JEOL Ltd.), and the amount of the siloxane compound is determined from the ratio of the siloxane compound-derived peak area to the DMF-derived peak area. The surface adhesion amount is calculated from the obtained amount of siloxane compound and the amount of silica particles from which the siloxane compound is liberated (silica particles having no siloxane compound adhered to the surface).

  The content of the specific silica particles in the resin particle composition according to the present embodiment is from the viewpoint of fluidity expression of the resin particles, expression of handleability of the resin particle composition, and air transportability of the resin particle composition. 0.05 mass% or more and 7.0 mass% or less are preferable with respect to the resin particle, 0.2 mass% or more and 4.5 mass% or less are more preferable, and 0.3 mass% or more and 3.0 mass% or less are preferable. Further preferred.

[Lubricant particles]
Next, the lubricant particles will be described.
The lubricant particles may be any particles that exhibit lubricity, and examples include fatty acid metal salt particles, inorganic lubricant particles, and resin lubricant particles.
The lubricant particles may be used singly or in combination of two or more.

Fatty acid metal salt particles include fatty acids (eg, fatty acids such as stearic acid, 12-hydroxystearic acid, palmitic acid, oleic acid, behenic acid, montanic acid, lauric acid, and other organic acids) and metals (eg, calcium, Zinc, iron, copper, manganese, lead, magnesium, aluminum, and other metals (Na, Li, etc.) and salt particles.
Above all, from the point of expression of excellent lubricity, one fatty acid selected from the group consisting of stearic acid, palmitic acid, oleic acid, lead oleate, lauric acid, zinc, calcium, iron, copper, magnesium, manganese Preferred are particles of a salt of one metal selected from the group consisting of lead.

Specific examples of fatty acid metal salt particles include zinc stearate, calcium stearate, iron stearate, copper stearate, zinc palmitate, magnesium palmitate, calcium palmitate, manganese oleate, lead oleate, and lauric acid. Examples thereof include particles such as zinc.
Among these, the fatty acid metal salt particles are preferably zinc stearate particles from the viewpoint of high lubricity and easy availability.

The fatty acid metal salt particles may be mixed particles of a plurality of types of fatty acid metal salts.
The fatty acid metal salt particles may be particles containing a fatty acid metal salt and other components.
Examples of other components include higher fatty acids and higher alcohols. However, the fatty acid metal salt particles preferably contain 1% by mass or more of the fatty acid metal salt from the viewpoint of the expression of lubricity.

Examples of the inorganic lubricant particles include particles having a function of cleaving and lubricating the substance itself, or particles causing internal slip.
Specific examples of the inorganic lubricant particles include mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, talc, kaolinite, montmorillonite, calcium fluoride, and graphite.
Among these, as the inorganic lubricant particles, boron nitride particles are preferable from the viewpoint of high lubricity.

  Examples of the resin lubricant particles include fluorine resin particles such as polytetrafluoroethylene (PTFE), and low molecular weight polyolefin particles such as polypropylene, polyethylene, and polybutene.

  Other lubricant particles include aliphatic amide particles such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide, carnauba wax, rice wax, candelilla wax, wood wax, jojoba oil, etc. Particles of plant waxes; Particles of animal waxes such as beeswax; Particles of mineral or petroleum waxes such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax; Is mentioned.

The selection of the lubricant particles may be performed according to the resin type constituting the resin particles, versatility, and the like.
From the viewpoint of high versatility with respect to resin particles, availability, and the like, the lubricant particles are preferably fatty acid metal salt particles.

  The average equivalent circle diameter on the volume basis of the lubricant particles can be appropriately determined according to the particle diameter of the resin particles, but is preferably 0.1 μm or more and 10.0 μm or less from the viewpoint of dispersibility in the resin particles. 0.2 μm or more and 10.0 μm or less is more preferable, and 0.2 μm or more and 8.0 μm or less is still more preferable.

The average equivalent circle diameter on the volume basis of the fatty acid metal salt particles is a value measured by the following method. As a measuring device, a laser diffraction / scattering particle size distribution measuring device “LA-920” (Horiba, Ltd.) is used. For setting of measurement conditions and analysis of measurement data, the exclusive software “HORIBA LA-920 for Windows (registered trademark) WET (LA-920) Ver.2.02 (Horiba, Ltd.)” attached to LA-920 is used. Use. As the measurement solvent, ion-exchanged water from which impure solids are removed in advance is used.
The average equivalent circular diameter of the inorganic lubricant particles based on the volume is determined by observing 100 primary particles of the inorganic lubricant particles with a SEM (Scanning Electron Microscope) apparatus, and obtaining the equivalent circle diameter by image analysis of the primary particles. The 50% diameter (D50v) in the cumulative frequency is measured by this method.

  The content of the lubricant particles in the resin particle composition according to the present embodiment is preferably 0.1% by mass or more and 8% by mass or less with respect to the resin particles, for example, from the viewpoint of expression of lubricity and pipe transportability. 1 mass% or more and 5 mass% or less are more preferable, and 2 mass% or more and 5 mass% or less are still more preferable.

[Resin particles]
Next, the resin particles will be described.
The resin particles are not particularly limited as long as the specific silica particles and the lubricant particles are easily attached to the shape, the particle diameter, and the material (component), and depending on the purpose of use such as the use of the resin particle composition according to the present embodiment. Just decide.

The shape of the resin particles is not particularly limited, but the volume average particle diameter D _50V of the resin particles is preferably 1 μm or more and 20 μm or less from the viewpoint of ease of application to air transportation and handling (handling properties). It is more preferably 15 μm or less, and further preferably 3 μm or more and 10 μm or less. When the volume average particle diameter of the resin particles is within the above range, a decrease in fluidity of the resin particle composition is easily suppressed.

  Here, the volume average particle diameter of the resin particles is measured using Coulter Multisizer II (manufactured by Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Coulter).

In the measurement, a measurement sample is added in a range of 0.5 mg to 50 mg in 2 ml of a 5% by weight aqueous solution of a surfactant such as sodium alkylbenzenesulfonate as a dispersant. This is added to 100 ml to 150 ml of electrolyte.
The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for 1 minute with an ultrasonic disperser, and the particle size distribution of particles in the range of 2 μm to 50 μm is measured with a Coulter Multisizer II using an aperture diameter of 100 μm. The number of particles to be sampled is 50,000.

The volume average particle size D _50V is defined as a particle size distribution in which a cumulative distribution is drawn from the smaller diameter side with respect to the divided particle size range (channel), and the volume is 50% cumulative. Specifically, the volume average particle diameter D _50V is obtained as follows. Using the volume distribution obtained by image analysis, a cumulative distribution is drawn to obtain a volume average particle diameter D _50V that is 50% cumulative in volume.

The resin constituting the resin particles is not particularly limited. As the resin constituting the resin particles, thermoplastic resins made of various natural or synthetic polymer substances can be used.
For example, polyolefin resins such as polyethylene and polypropylene; polystyrene resins such as polystyrene and acrylonitrile / butadiene / styrene copolymer (ABS resin); acrylic resins such as polymethyl methacrylate and polybutyl acrylate; rubbers such as polybutadiene and polyisoprene (Co) polymers; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Vinyl resins such as vinyl chloride resins, vinyl aromatic resins, and polyvinyl resins; Epoxy resins; Conjugated diene resins; Polyamide resins; Polyacetal resins; A thermoplastic polyurethane resin; a fluororesin; and the like.
These resins may be used alone or in combination of two or more.

  The resin constituting the resin particles is typically a resin having a weight average molecular weight of 5,000 to 100,000 (epoxy resin, styrene-acrylic resin, polyamide resin, polyester resin, polyvinyl resin, polyolefin resin, polyurethane resin, polybutadiene Resin). These resins may be used alone or in combination of two or more. A suitable resin may be selected according to the intended use, but it is usually highly effective for highly polar resins, and is more effective for those having many polar groups on the resin surface. From the standpoint of ease, the resin is preferably a polyester resin, and the kneading and pulverizing method is preferable.

  In addition, the resin particle may contain additives, such as a ultraviolet absorber and antioxidant, according to the intended use.

<Method for producing resin particle composition>
The resin particle composition according to the present embodiment is produced, for example, by the following method.
That is, the resin particle composition according to the present embodiment includes a step of preparing specific silica particles, lubricant particles, and resin particles (hereinafter referred to as “particle preparation step”), a specific silica particle, lubricant particles, and And a step of mixing resin particles (hereinafter referred to as “particle mixing step”).

[Particle preparation process]
First, in the particle preparation step, specific silica particles, lubricant particles, and resin particles included in the resin particle composition according to the present embodiment are prepared.
In particular, regarding the specific silica particles and resin particles, those manufactured by the following manufacturing method may be used.

-Production of specific silica particles-
The specific silica particles surface-treat the surface of the silica particles with a siloxane compound having a viscosity of 1000 cSt or more and 50000 cSt or less so that the surface adhesion amount is 0.01% by mass or more and 5% by mass or less with respect to the silica particles. Can be obtained.

Examples of the surface treatment method include a method of surface-treating the surface of silica particles with a siloxane compound in supercritical carbon dioxide; and a method of surface-treating the surface of silica particles with a siloxane compound in air.
Specifically, as the surface treatment method, for example, using supercritical carbon dioxide, a siloxane compound is dissolved in supercritical carbon dioxide, and the siloxane compound is adhered to the surface of silica particles; A method in which a solution containing a siloxane compound and a solvent that dissolves the siloxane compound is applied to the surface of the silica particles (for example, spraying or coating), and the siloxane compound is adhered to the surface of the silica particles; And a method of adding a solution containing a siloxane compound and a solvent for dissolving the siloxane compound and holding the solution, followed by drying the silica particle dispersion and the mixed solution of the solutions.
Here, “supercritical carbon dioxide” is carbon dioxide in a state of temperature and pressure above the critical point, and has both gas diffusibility and liquid solubility.

Among these, as the surface treatment method, a method of attaching a siloxane compound to the surface of silica particles using supercritical carbon dioxide is preferable.
When the surface treatment is performed in supercritical carbon dioxide, the siloxane compound is dissolved in the supercritical carbon dioxide. Since supercritical carbon dioxide has the characteristic of low interfacial tension, the siloxane compound dissolved in supercritical carbon dioxide reaches the surface of the silica particle by diffusing deeply with the supercritical carbon dioxide. It is considered that the surface treatment with the siloxane compound is performed not only on the surface of the silica particles but also deep in the hole.
For this reason, the silica particles surface-treated with the siloxane compound in supercritical carbon dioxide are attached to the specific silica with the siloxane compound having a nearly uniform surface (for example, a surface treatment layer formed in a thin film). It is thought to become particles.

Moreover, you may perform the surface treatment which provides hydrophobicity to the surface of a silica particle using a hydrophobic treatment agent with a siloxane compound in supercritical carbon dioxide.
In this case, the hydrophobizing agent is dissolved in the supercritical carbon dioxide together with the siloxane compound, and the siloxane compound and the hydrophobizing agent in the supercritical carbon dioxide are dissolved in the silica particles together with the supercritical carbon dioxide. It is considered that the surface is easily diffused to reach the pores, and the surface treatment with the siloxane compound and the hydrophobizing agent is considered to be performed not only on the surface of the silica particles but also deep in the pores.
As a result, the silica particles surface-treated with the siloxane compound and the hydrophobizing agent in supercritical carbon dioxide adhere to the surface in a nearly uniform state with the siloxane compound and the hydrophobizing agent, and high hydrophobicity is easily imparted. Become.

The specific silica particles are preferably those produced by the following method.
The specific silica particles include, for example, a step of preparing a silica particle dispersion containing silica particles and a solvent containing alcohol and water by a sol-gel method (hereinafter referred to as “dispersion preparation step”), supercritical carbon dioxide. And removing the solvent from the silica particle dispersion (hereinafter referred to as “solvent removal process”), and the surface of the silica particles after removing the solvent in supercritical carbon dioxide is surface-treated with a siloxane compound. And a process (hereinafter referred to as “surface treatment process”).

As described above, when the solvent is removed from the silica particle dispersion using supercritical carbon dioxide, the generation of coarse powder is easily suppressed.
The reasons for this are not clear, but 1) When removing the solvent of the silica particle dispersion, the supercritical carbon dioxide has the property that “interfacial tension does not work”. 2) Supercritical carbon dioxide “carbon dioxide in a state of temperature and pressure above the critical point, both gas diffusibility and liquid solubility” Due to the property of “having”, the supercritical carbon dioxide is efficiently contacted at a relatively low temperature (for example, 250 ° C. or lower) and the solvent is dissolved. By removing the supercritical carbon dioxide in which the solvent is dissolved, The reason is considered that the solvent in the silica particle dispersion can be removed without generating coarse powder such as secondary aggregates due to condensation of silanol groups.

Here, the solvent removal step and the surface treatment step may be performed separately, but are preferably performed continuously (that is, each step is performed without being released under atmospheric pressure). By performing these steps continuously, after the solvent removal step, the surface treatment step can be performed in a state in which the silica particles have no opportunity to adsorb moisture and the adsorption of excessive moisture to the silica particles is suppressed.
This eliminates the need to use a large amount of a siloxane compound, perform excessive heating and perform a solvent removal step and a surface treatment step at a high temperature. As a result, the generation of coarse powder can be suppressed more effectively.

Hereinafter, the dispersion preparation step, the solvent removal step, and the surface treatment step will be described in detail.
In addition, the manufacturing method of specific silica particle is not necessarily restricted to the method performed by said 3 process, For example, as above-mentioned, 1) the aspect which uses supercritical carbon dioxide only for a surface treatment process, 2) each The aspect etc. which perform a process separately may be sufficient.

-Dispersion preparation process In a dispersion preparation process, the silica particle dispersion containing a silica particle and the solvent containing alcohol and water is prepared, for example.
Specifically, in the dispersion preparation step, for example, a silica particle dispersion is prepared by a wet method (for example, a sol-gel method) and prepared.
In particular, the silica particle dispersion is a sol-gel method as a wet method (specifically, a tetraalkoxysilane is reacted with an alcohol and water solvent in the presence of an alkali catalyst to cause a reaction (hydrolysis reaction, condensation reaction)). It is good to produce by the method of producing | generating particle | grains.

In addition, the preferable range of the average equivalent circle diameter of the silica particles and the preferable range of the average circularity are as described above, and it is preferable to prepare silica particles (untreated silica particles) so as to be within this range.
In the dispersion preparation step, for example, when silica particles are obtained by a wet method, the silica particles are obtained in a state of dispersion in which silica particles are dispersed in a solvent (silica particle dispersion).

In addition, when shifting to the solvent removal step, in the silica particle dispersion to be prepared, the mass ratio of the silica particles to the silica particle dispersion is, for example, 0.05 or more and 0.7 or less, preferably 0.2 or more. 0.65 or less, more preferably 0.3 or more and 0.6 or less.
When the mass ratio of the silica particles to the silica particle dispersion is less than 0.05, the amount of supercritical carbon dioxide used in the solvent removal step increases, and productivity may deteriorate.
Moreover, when the mass ratio of the silica particles to the silica particle dispersion exceeds 0.7, the distance between the silica particles is reduced in the silica particle dispersion, and coarse powder due to aggregation or gelation of the silica particles is likely to occur. There is.

-Solvent removal process A solvent removal process is a process of distribute | circulating supercritical carbon dioxide and removing the solvent of a silica particle dispersion liquid, for example.
That is, the solvent removal step is a step of removing the solvent by bringing the supercritical carbon dioxide into contact with the silica particle dispersion by circulating the supercritical carbon dioxide.
Specifically, in the solvent removal step, for example, a silica particle dispersion is introduced into a closed reactor. Thereafter, liquefied carbon dioxide is added to the sealed reactor and heated, and the pressure in the reactor is increased by a high-pressure pump to bring the carbon dioxide into a supercritical state. Then, the supercritical carbon dioxide is introduced into the closed reactor and discharged, and is passed through the closed reactor, that is, the silica particle dispersion.
As a result, the supercritical carbon dioxide dissolves the solvent (alcohol and water) and accompanies it to the outside of the silica particle dispersion (outside of the sealed reactor), and the solvent is removed.

The temperature condition for solvent removal, that is, the temperature of supercritical carbon dioxide is, for example, preferably 31 ° C. or higher and 350 ° C. or lower, preferably 60 ° C. or higher and 300 ° C. or lower, more preferably 80 ° C. or higher and 250 ° C. or lower.
When this temperature is less than 31 ° C., the solvent is difficult to dissolve in supercritical carbon dioxide, and thus it may be difficult to remove the solvent. In addition, it is considered that coarse powder is likely to be generated due to the liquid crosslinking force of a solvent or supercritical carbon dioxide. On the other hand, when this temperature exceeds 350 ° C., it is considered that coarse powder such as secondary aggregates may be easily generated due to condensation of silanol groups on the surface of the silica particles.

The pressure condition for removing the solvent, that is, the pressure of supercritical carbon dioxide is, for example, 7.38 MPa or more and 40 MPa or less, preferably 10 MPa or more and 35 MPa or less, more preferably 15 MPa or more and 25 MPa or less.
If this pressure is less than 7.38 MPa, the solvent tends to be difficult to dissolve in supercritical carbon dioxide, whereas if the pressure exceeds 40 MPa, the equipment tends to be expensive.

The amount of supercritical carbon dioxide introduced into and discharged from the closed reactor is, for example, preferably from 15.4 L / min / m ^{3 to} 1540 L / min / m ³ , and preferably 77 L / min / m. ³ or more and 770 L / min / m ³ or less.
When the introduction / discharge amount is less than 15.4 L / min / m ³ , it takes time to remove the solvent, and thus the productivity tends to be deteriorated. On the other hand, when the introduction / discharge amount exceeds 1540 L / min / m ³ , supercritical carbon dioxide undergoes a short path, the contact time of the silica particle dispersion is shortened, and the solvent tends to be difficult to remove efficiently. .

-Surface treatment process A surface treatment process is a process of surface-treating the surface of a silica particle with a siloxane compound in a supercritical carbon dioxide continuously with a solvent removal process, for example.
That is, in the surface treatment step, for example, the surface of the silica particles is surface-treated with the siloxane compound in supercritical carbon dioxide without being released into the atmosphere before shifting from the solvent removal step.
Specifically, in the surface treatment step, for example, after introducing and discharging supercritical carbon dioxide into the closed reactor in the solvent removal step, the temperature and pressure in the closed reactor are adjusted, and the closed reactor In a state where supercritical carbon dioxide is present, a certain proportion of the siloxane compound is added to the silica particles. Then, the surface treatment of the silica particles is performed by reacting the siloxane compound in a state in which this state is maintained, that is, in supercritical carbon dioxide.

  Here, in the surface treatment process, the reaction of the siloxane compound may be performed in supercritical carbon dioxide (that is, in an atmosphere of supercritical carbon dioxide). Surface treatment may be performed while introducing or discharging critical carbon dioxide, or surface treatment may be performed in a non-circulating manner.

In the surface treatment step, the amount of silica particles relative to the reactor volume (that is, the charged amount) is, for example, preferably 30 g / L or more and 600 g / L or less, preferably 50 g / L or more and 500 g / L or less, more preferably 80 g / L. L to 400 g / L.
When the amount is less than the above range, the concentration of the siloxane compound with respect to supercritical carbon dioxide is lowered, the contact probability with the surface of the silica particles is lowered, and the reaction may be difficult to proceed. On the other hand, when the amount is larger than the above range, the concentration of the siloxane compound with respect to the supercritical carbon dioxide becomes high, and the siloxane compound cannot be completely dissolved in the supercritical carbon dioxide, resulting in poor dispersion and easy generation of coarse aggregates.

The density of supercritical carbon dioxide is, for example, 0.10 g / ml or more and 0.80 g / ml or less, preferably 0.10 g / ml or more and 0.60 g / ml or less, more preferably 0.2 g / ml or more and 0 or less. .50 g / ml or less.
When this density is lower than 0.10 g / ml, the solubility of the siloxane compound with respect to supercritical carbon dioxide tends to decrease, and aggregates tend to be generated. On the other hand, when the density is higher than 0.80 g / ml, the diffusibility of the silica particles into the pores is lowered, so that the surface treatment may be insufficient. In particular, the sol-gel silica particles containing a large amount of silanol groups are preferably subjected to surface treatment in the above density range.
The density of supercritical carbon dioxide is adjusted by temperature, pressure, and the like.

The temperature condition of the surface treatment, that is, the temperature of supercritical carbon dioxide is, for example, 80 ° C. or higher and 300 ° C. or lower, preferably 100 ° C. or higher and 250 ° C. or lower, more preferably 120 ° C. or higher and 200 ° C. or lower.
When this temperature is less than 80 ° C., the surface treatment ability by the siloxane compound may be lowered. On the other hand, when the temperature exceeds 300 ° C., the condensation reaction between silanol groups of the silica particles proceeds and particle aggregation may occur. In particular, the sol-gel silica particles containing a large amount of silanol groups are preferably subjected to a surface treatment in the above temperature range.

  On the other hand, the pressure condition of the surface treatment, that is, the pressure of supercritical carbon dioxide may be a condition that satisfies the above density, but for example, it is preferably 8 MPa or more and 30 MPa or less, preferably 10 MPa or more and 25 MPa or less, more preferably 15 MPa or more. 20 MPa or less.

Specific examples of the siloxane compound used for the surface treatment are as described above. Moreover, the preferable range of the viscosity of the siloxane compound is as described above.
Among the siloxane compounds, when silicone oil is applied, the silicone oil tends to adhere to the surface of the silica particles in a nearly uniform state, and the fluidity, dispersibility, and handleability of the specific silica particles are easily improved.

  The amount of the siloxane compound used is, for example, from 0.05% by mass to 3% by mass with respect to the silica particles from the viewpoint of easily controlling the surface adhesion amount to the silica particles to 0.01% by mass or more and 5% by mass or less. It is preferably 0.1% by mass or more and 2% by mass or less, more preferably 0.15% by mass or more and 1.5% by mass or less.

  In addition, although a siloxane compound may be used independently, you may use it as a liquid mixture with the solvent in which a siloxane compound is easy to melt | dissolve. Examples of the solvent include toluene, methyl ethyl ketone, methyl isobutyl ketone and the like.

  In the surface treatment step, the surface treatment of the silica particles may be performed with a mixture containing a hydrophobizing agent together with the siloxane compound.

Examples of the hydrophobizing agent include silane-based hydrophobizing agents. Examples of the silane hydrophobizing agent include known silicon compounds having an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group), and specific examples include, for example, a silazane compound (for example, methyltrimethoxy). Silane compounds such as silane, dimethyldimethoxysilane, trimethylchlorosilane, and trimethylmethoxysilane, hexamethyldisilazane, tetramethyldisilazane, and the like. The hydrophobizing agent may be used alone or in combination.
Among the silane-based hydrophobizing agents, silicon compounds having a trimethyl group such as trimethylmethoxysilane and hexamethyldisilazane (HMDS), particularly hexamethyldisilazane (HMDS) are preferable.

  The amount of the hydrophobizing agent used is not particularly limited. For example, the amount is preferably 1% by mass or more and 100% by mass or less, and preferably 3% by mass or more and 80% by mass or less, more preferably 5% with respect to the silica particles. It is not less than 50% by mass.

  The hydrophobizing agent may be used alone, but may be used as a mixed solution with a solvent in which the hydrophobizing agent is easily dissolved. Examples of the solvent include toluene, methyl ethyl ketone, methyl isobutyl ketone and the like.

-Manufacture of resin particles-
The method for producing the resin particles may be determined according to the type of resin, the particle shape, and the like, and is not particularly limited.
Resin particles are, for example, a method in which a resin is melt-kneaded and then pulverized and classified (kneading and pulverization method), and an oil phase in which a resin is dissolved in a water-soluble organic solvent is suspended and dispersed in an aqueous phase containing a dispersant. Then, it is produced by a method of removing a solvent (dissolution suspension method), a method of agglomerating a resin obtained from a resin monomer by emulsion polymerization or the like (emulsion polymerization aggregation method), or the like.

[Particle mixing process]
In the particle mixing step, specific silica particles, lubricant particles, and resin particles are mixed.
For mixing the specific silica particles, the lubricant particles, and the resin particles, a V-type blender, a Henschel mixer, a Ladige mixer, or the like is used.
The specific silica particles and the lubricant particles may be separately mixed with the resin particles.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention. Further, “parts” and “%” are based on mass unless otherwise specified.

(Preparation of silica particle dispersion (1))
To a 1.5 L glass reaction vessel equipped with a stirrer, a dropping nozzle, and a thermometer, 300 parts of methanol and 70 parts of 10% ammonia water were added and mixed to obtain an alkali catalyst solution.
After adjusting this alkali catalyst solution to 30 ° C., 185 parts of tetramethoxysilane and 50 parts of 8.0% aqueous ammonia are simultaneously added dropwise with stirring to obtain a hydrophilic silica particle dispersion (solid content concentration of 12. 0% by mass) was obtained. Here, the dropping time was 30 minutes.
Then, the obtained silica particle dispersion was concentrated to a solid content concentration of 40% by mass with a rotary filter R-Fine (manufactured by Kotobuki Industries). This concentrated product was used as a silica particle dispersion (1).

(Preparation of silica particle dispersions (2) to (4))
In the preparation of the silica particle dispersion (1), according to Table 1, an alkali catalyst solution (amount of methanol and 10% ammonia water), silica particle production conditions (tetramethoxysilane (denoted as TMOS) in the alkali catalyst solution) and 8% Silica particle dispersions (2) to (8) were prepared in the same manner as the silica particle dispersion (1) except that the total amount of ammonia water dropped and the dropping time) were changed.

  Table 1 summarizes the silica particle dispersions (1) to (8).

(Preparation of surface-treated silica particles (S1))
Using the silica particle dispersion (1), the silica particles were surface-treated with a siloxane compound in a supercritical carbon dioxide atmosphere as shown below. In addition, the apparatus equipped with the carbon dioxide cylinder, the carbon dioxide pump, the entrainer pump, the autoclave with a stirrer (capacity 500 ml), and the pressure valve was used for the surface treatment.

  First, 250 parts of the silica particle dispersion (1) was charged into an autoclave with a stirrer (capacity 500 ml), and the stirrer was rotated at 100 rpm. Thereafter, liquefied carbon dioxide was injected into the autoclave, and the temperature was raised by a carbon dioxide pump while the temperature was raised by a heater, and the inside of the autoclave was brought to a supercritical state of 150 ° C. and 15 MPa. While maintaining the inside of the autoclave at 15 MPa with a pressure valve, supercritical carbon dioxide is circulated from a carbon dioxide pump, methanol and water are removed from the silica particle dispersion (1) (solvent removal step), and silica particles (untreated silica particles) )

Next, the distribution of the supercritical carbon dioxide was stopped when the distribution amount of the supercritical carbon dioxide distributed (accumulated amount: measured as the distribution amount of carbon dioxide in the standard state) reached 900 parts.
Thereafter, with a temperature of 150 ° C. by a heater and a pressure of 15 MPa by a carbon dioxide pump, in a state where the supercritical state of carbon dioxide is maintained in an autoclave, with respect to 100 parts of the silica particles (untreated silica particles), In advance, 20 parts of hexamethyldisilazane (HMDS: manufactured by Organic Synthetic Chemical Industry Co., Ltd.) as a hydrophobizing agent and dimethyl silicone oil (DSO: trade name “KF-96”: Shin-Etsu Chemical Co., Ltd.) having a viscosity of 10,000 cSt as a siloxane compound (Manufactured) After 0.3 parts of the treating agent solution was poured into the autoclave by an entrainer pump, the mixture was reacted at 180 ° C. for 20 minutes while stirring. Thereafter, supercritical carbon dioxide was circulated again to remove excess treating agent solution. Then, stirring was stopped, the pressure valve was opened, the pressure in the autoclave was released to atmospheric pressure, and the temperature was lowered to room temperature (25 ° C.).
Thus, the solvent removal process and the surface treatment with a siloxane compound were sequentially performed to obtain surface-treated silica particles (S1).

(Production of surface-treated silica particles (S2) to (S5), (S7) to (S9), (S12) to (S17))
In preparation of surface-treated silica particles (S1), the silica particle dispersion, surface treatment conditions (treatment atmosphere, siloxane compound (seed, viscosity and added amount thereof), hydrophobizing agent and added amount thereof) were changed according to Table 2. Except that, surface-treated silica particles (S2) to (S5), (S7) to (S9), and (S12) to (S17) were produced in the same manner as the surface-treated silica particles (S1).

(Preparation of surface-treated silica particles (S6))
Using a dispersion similar to the silica particle dispersion (1) used in the preparation of the surface-treated silica particles (S1), the silica particles are subjected to a surface treatment with a siloxane compound in an air atmosphere as shown below. It was.
Attach an ester adapter and a condenser tube to the reaction vessel used to prepare the silica particle dispersion (1), heat the silica particle dispersion (1) to 60 ° C. to 70 ° C. and distill off the methanol, and then add water. Furthermore, it heated at 70 to 90 degreeC, methanol was distilled off, and the aqueous dispersion of the silica particle was obtained. The surface of the silica particles was treated by adding 3 parts of methyltrimethoxysilane (MTMS: manufactured by Shin-Etsu Chemical Co., Ltd.) at room temperature to 100 parts of the solid content of the silica particles in the aqueous dispersion and reacting for 2 hours. After adding methyl isobutyl ketone to this surface treatment dispersion, the mixture is heated to 80 ° C. to 110 ° C. to distill off methanol water, and hexamethyldiethylene is added at room temperature to 100 parts of the solid content of silica particles in the obtained dispersion. 80 parts of silazane (HMDS: manufactured by Organic Synthetic Chemical Industry Co., Ltd.) and 1.0 part of dimethyl silicone oil (DSO: trade name “KF-96”: manufactured by Shin-Etsu Chemical Co., Ltd.) having a viscosity of 10,000 cSt as a siloxane compound are added, The mixture was reacted at 120 ° C. for 3 hours, cooled, and dried by spray drying to obtain surface-treated silica particles (S6).

(Preparation of surface-treated silica particles (S10))
In the production of the surface-treated silica particles (S1), fumed silica: AEROSIL OX50 (Japan) was used instead of silica particles (untreated silica particles) obtained by removing methanol and water from the silica particle dispersion (1). Surface-treated silica particles (S10) were produced in the same manner as in the production of the surface-treated silica particles (S1) except that Aergil Corporation was used.
That is, 100 parts of AEROSIL OX50 was put into the same autoclave with a stirrer as in the production of the surface-treated silica particles (S1), and the stirrer was rotated at 100 rpm. Thereafter, liquefied carbon dioxide was injected into the autoclave, and the temperature was raised with a carbon dioxide pump while raising the temperature with a heater, so that the inside of the autoclave was brought to a supercritical state of 180 ° C. and 15 MPa. While maintaining the interior of the autoclave at 15 MPa with a pressure valve, 20 parts of hexamethyldisilazane (HMDS: manufactured by Organic Synthetic Chemical Industries) as a hydrophobization treatment agent in advance and dimethyl silicone oil (DSO: trade name) having a viscosity of 10,000 cSt as a siloxane compound “KF-96” (manufactured by Shin-Etsu Chemical Co., Ltd.) A processing agent solution in which 0.3 part was dissolved was injected into the autoclave with an entrainer pump and then reacted at 180 ° C. for 20 minutes with stirring. Critical carbon dioxide was circulated to remove excess treating agent solution to obtain surface-treated silica particles (S10).

(Preparation of surface-treated silica particles (S11))
The surface except that fumed silica: AEROSIL A50 (manufactured by Aergil Japan) was used instead of silica particles (untreated silica particles) obtained by removing methanol and water from the silica particle dispersion (1). Surface-treated silica particles (S11) were produced according to the treated silica particles (S1).
That is, 100 parts of AEROSIL A50 was charged into the same autoclave with a stirrer as in the preparation of the surface-treated silica particles (S1), and the stirrer was rotated at 100 rpm. Thereafter, liquefied carbon dioxide was injected into the autoclave, and the temperature was raised with a carbon dioxide pump while raising the temperature with a heater, so that the inside of the autoclave was brought to a supercritical state of 180 ° C. and 15 MPa. While maintaining the pressure in the autoclave at 15 MPa with a pressure valve, 40 parts of hexamethyldisilazane (HMDS: manufactured by Organic Synthetic Chemical Industries) as a hydrophobizing agent and dimethyl silicone oil (DSO: trade name) having a viscosity of 10000 cSt as a siloxane compound are prepared in advance. "KF-96 (manufactured by Shin-Etsu Chemical Co., Ltd.)") 1.0 parts of the treating agent solution was injected into the autoclave with an entrainer pump, and then reacted at 180 ° C for 20 minutes with stirring. Supercritical carbon dioxide was circulated to remove the excess treating agent solution to obtain surface-treated silica particles (S11).

(Preparation of surface-treated silica particles (SC1))
In the production of the surface-treated silica particles (S1), the surface-treated silica particles (SC1) were produced in the same manner as the production of the surface-treated silica particles (S1) except that the siloxane compound was not added.

(Production of surface-treated silica particles (SC2) to (SC4))
In preparation of surface-treated silica particles (S1), the silica particle dispersion, surface treatment conditions (treatment atmosphere, siloxane compound (seed, viscosity and added amount thereof), hydrophobizing agent and added amount thereof) were changed according to Table 3. Except that, surface-treated silica particles (SC2) to (SC4) were produced in the same manner as in the production of the surface-treated silica particles (S1).

(Preparation of surface-treated silica particles (SC5))
In the production of the surface-treated silica particles (S6), the surface-treated silica particles (SC5) were produced in the same manner as in the production of the surface-treated silica particles (S6) except that no siloxane compound was added.

(Preparation of surface-treated silica particles (SC6))
The silica particle dispersion (8) is filtered, dried at 120 ° C., then placed in an electric furnace and baked at 400 ° C. for 6 hours, and then 10 parts of HMDS is sprayed on 100 parts of silica particles by spray drying. It dried and produced the surface treatment silica particle (SC6).

  For the surface-treated silica particles obtained in each example, the average equivalent circle diameter, the average circularity, the adhesion amount of the siloxane compound to the untreated silica particles, the compression agglomeration degree, the particle compression ratio, and the particle dispersion degree are the methods described above. Measured with

（樹脂粒子（Ａ）の作製）
撹拌機、温度計、コンデンサー、窒素ガス導入管を備えた反応容器中に、テレフタル酸ジメチル２３ｍｏｌ％、イソフタル酸１０ｍｏｌ％、ドデセニルコハク酸無水物１５ｍｏｌ％、トリメリット酸無水物３ｍｏｌ％、ビスフェノールＡエチレンオキサイド２モル付加物５ｍｏｌ％、ビスフェノールＡプロピレンオキサイド２モル付加物４５ｍｏｌ％の割合で投入し、反応容器中を乾燥窒素ガスで置換した後、触媒としてジブチルスズオキシド０．０６ｍｏｌ％の割合で加え、窒素ガス気流下約１９０℃で約７時間撹拌反応させ、更に温度を約２５０℃に上げて約５．０時間撹拌反応させた後、反応容器内を１０．０ｍｍＨｇまで減圧し、減圧下で約０．５時間撹拌反応させて、分子内に極性基を有するポリエステル樹脂を得た。
次に、ポリエステル樹脂１００部を、バンバリーミキサー型混練機で溶融混練した。混練物を圧延ロールで厚さ１ｃｍ程度の板状に成形し、フィッツミル型粉砕機で数ミリ程度まで粗粉砕し、ＩＤＳ型粉砕機で微粉砕を行った後、エルボー型分級機で分級を順次行い、体積平均粒径７μｍの樹脂粒子Ａを得た。

(Preparation of resin particles (A))
In a reaction vessel equipped with a stirrer, thermometer, condenser and nitrogen gas inlet tube, dimethyl terephthalate 23 mol%, isophthalic acid 10 mol%, dodecenyl succinic anhydride 15 mol%, trimellitic anhydride 3 mol%, bisphenol A ethylene oxide 2 mol adduct 5 mol% and bisphenol A propylene oxide 2 mol adduct 45 mol% were charged and the reaction vessel was purged with dry nitrogen gas, and then added as a catalyst at a rate of 0.06 mol% dibutyltin oxide and nitrogen gas. The mixture was allowed to stir at about 190 ° C. for about 7 hours under a stream of air, and the temperature was further raised to about 250 ° C. for about 5.0 hours. After that, the reaction vessel was depressurized to 10.0 mmHg and about 0.0. A polyester resin having a polar group in the molecule was obtained by stirring for 5 hours.
Next, 100 parts of the polyester resin was melt-kneaded with a Banbury mixer type kneader. The kneaded product is formed into a plate shape with a thickness of about 1 cm with a rolling roll, coarsely pulverized to about several millimeters with a Fitzmill type pulverizer, finely pulverized with an IDS type pulverizer, and then classified with an elbow type classifier. Sequentially, resin particles A having a volume average particle diameter of 7 μm were obtained.

(Preparation of resin particles (B) and (C))
In the production of the resin particles (A), classification was performed sequentially with an elbow classifier to obtain resin particles (B) having a volume average particle diameter of 1 μm and resin particles (C) having a volume average particle diameter of 15 μm.

(Preparation of resin particles (D))
-Preparation of resin particle dispersion-
A mixture of 285 parts of styrene, 115 parts of n-butyl acrylate, 8 parts of acrylic acid, and 24 parts of dodecanethiol was dissolved in 6 parts of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) Anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is emulsified in a flask in which 550 parts of ion-exchanged water are dissolved, and 4 parts of ammonium persulfate is dissolved in this while slowly mixing for 10 minutes. 50 parts of ion-exchanged water was added. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the contents reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion in which resin particles having an average particle diameter of 150 nm, a glass transition temperature (Tg) = 53 ° C., and a weight average molecular weight Mw = 32,000 was obtained. The solid content concentration of this dispersion was 40%.

-Preparation of release agent dispersion-
Carnauba wax (manufactured by Toa Kasei Co., Ltd.) 5 parts: 45 parts Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 5 parts Ion exchange water: 200 parts The above ingredients are mixed and heated to 120 ° C. Then, after dispersion with IKA Ultra Turrax T50, dispersion treatment was performed with a pressure discharge type gorin homogenizer to obtain a release agent dispersion having a release agent particle center particle size of 196 nm and a solid content of 22.0%. .

-Preparation of release agent-containing resin particles-
・ Resin particle dispersion 320 parts ・ Releasing agent dispersion 16 parts ・ Polyaluminum hydroxide (Pho2S manufactured by Asada Chemical Co., Ltd.) 0.5 parts ・ Ion-exchanged water 600 parts In a round stainless steel flask Were mixed and dispersed using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then heated to 40 ° C. while stirring the inside of the flask in an oil bath for heating. After maintaining at 40 ° C. for 30 minutes, it was confirmed that aggregated particles having an average particle diameter (D50) of 4.5 μm were generated. Further, the temperature of the heating oil bath was raised and maintained at 56 ° C. for 1.5 hours, and D50 was 6.8 μm.
After adding 1N sodium hydroxide to the dispersion containing the aggregate particles and adjusting the pH of the system to 5.0, the stainless steel flask is sealed, and stirring is continued to 95 ° C. using a magnetic seal. Heated and held for 4 hours. After cooling, the resin particles were filtered off, washed four times with ion exchange water, and then lyophilized to obtain resin particles (D) having a volume average particle size of 6.3 μm.
In the resin particles (D), the content of the release agent was 5% by mass.
The exposure rate of the release agent for the resin particles (D) was 8 atom%, and the average circularity was 0.95.

(Preparation of lubricant particles)
The following were prepared as lubricant particles.
Lubricant particles (a): Zinc stearate particles (Nissan Electol (registered trademark) MZ-2, average equivalent circle diameter of 1.5 μm based on volume, manufactured by NOF Corporation)
Lubricant particles (b): Boron nitride particles (FS-1, average equivalent circle diameter by volume of 0.5 μm, manufactured by Mizushima Alloy Iron Co., Ltd.)
Lubricant particles (c): polytetrafluoroethylene particles (Lublon (registered trademark) L-2, average equivalent circle diameter of 3.5 μm based on volume) manufactured by Daikin Industries, Ltd.

<Examples 1 to 25 and Comparative Examples 1 to 7>
According to Table 4 and Table 5, 20 parts of resin particles (A) are combined with surface-treated silica particles and lubricant particles, mixed in a 0.4 L sample mill at 15000 rpm for 30 seconds, and the resin particle composition of Example 1 I got a thing.

<Evaluation of resin particle composition>
About the resin particle composition obtained in Examples 1 to 25 and Comparative Examples 1 to 7, the handleability of the resin particle composition, the fluidity of the resin particles, and the pipes when the resin particle composition is air-fed The amount of fixing was evaluated by the following method.
The results are shown in Tables 4 and 5.

(Evaluation of handleability of resin particle composition)
As an index of the handleability of the resin particle composition, the resin particle composition obtained in each example was evaluated as the environment handleability at high temperature. Specifically, the resin composition was left in a high temperature and low humidity environment (temperature 30 ° C., humidity 20% RH) for 17 hours, and then mixed by shaking for 25 minutes using a shaker. It was placed on a sieve and vibrated for 90 seconds with an amplitude of 1 mm, and the state of the resin particles falling of the resin particle composition was observed and evaluated based on the following evaluation criteria.
-Evaluation criteria-
A: Resin particles do not remain on the sieve.
B: Some resin particles remain on the sieve.
C: Considerable resin particles remain on the sieve.

(Evaluation of fluidity of resin particle composition)
Using a powder tester manufactured by Hosokawa Micron Corporation, measure the loose specific gravity and solid apparent specific gravity of the resin particle composition used for the evaluation of the handleability of the resin particle composition, and use the following formula to find the loose apparent The compression ratio was determined from the ratio between the specific gravity and the apparent apparent specific gravity, and the fluidity of the resin particle composition was evaluated from the calculated compression ratio.
Formula: Compression ratio = [(Fixed apparent specific gravity) − (Loose apparent specific gravity)] / Folded apparent specific gravity Note that “loose apparent specific gravity” refers to filling a sample cup having a capacity of 100 cm 3 with a resin particle composition and weighing. It is a measured value derived from the above, and refers to the filling specific gravity in a state where the resin particle composition is naturally dropped into the sample cup. The “solid apparent specific gravity” refers to the apparent specific gravity in which the particles of the resin particle composition are degassed by tapping from the state of the loose apparent specific gravity, and the particles of the resin particle composition are rearranged and packed more densely. In addition, in the fluidity evaluation, similarly to the evaluation of the dispersion maintaining property, the mechanical load is given by mixing for 60 minutes with a tumbler shaker before the measurement. Assess based on the following criteria.
-Evaluation criteria-
A: Compression ratio is less than 0.2 B: Compression ratio is 0.2 or more and less than 0.3 C: Compression ratio is 0.3 or more and less than 0.4 D: Compression ratio is 0.4 or more

-Evaluation of adhesion amount (adhesion amount) in piping when resin particle composition is sent by air-
A pipe with room temperature curable silicone resin (SR2411, manufactured by Toray Dow Corning Silicone Co., Ltd.) on the inside of a pipe with an inner diameter of 47.8 mm. On the other hand, a suction test of the resin particle composition was conducted by installing a filter at the suction destination with a blower so that the linear velocity was 5.0 m / min. Thereafter, the resin particles were air-fed so that the solid-gas ratio was 0.5, and the proportion of the total amount of pipe adhering after 3 minutes was evaluated based on the following evaluation criteria.
-Evaluation criteria-
A: Piping adhesion amount is less than 1% B: Piping adhesion amount is 1% or more and less than 5% C: Piping adhesion amount is 5% or more

  From the above results, this example is superior to the comparative example in the fluidity of the resin particles and the handleability of the resin particle composition, and the adhesion amount (adhesion) in the pipe when the resin particle composition is air-fed It can be seen that the amount is small.

Claims (6)

Resin particles,
Lubricant particles;
Silica particles having a compression aggregation degree of 60% to 95% and a particle compression ratio of 0.20 to 0.40;
A resin particle composition having:   2. The resin particle composition according to claim 1, wherein the content of the lubricant particles with respect to the resin particles is 0.1% by mass or more and 8% by mass or less.   The resin particle composition according to claim 1 or 2, wherein the silica particles have an average equivalent-circle diameter of 40 nm or more and 200 nm or less.   The resin particle composition according to any one of claims 1 to 3, wherein a degree of particle dispersion of the silica particles is 90% or more and 100% or less.   The silica particles are surface-treated with a siloxane compound having a viscosity of 1000 cSt or more and 50000 cSt or less, and the surface adhesion amount of the siloxane compound is 0.01% by mass or more and 5% by mass or less. The resin particle composition described in 1.   The resin particle composition according to claim 5, wherein the siloxane compound is silicone oil.