JP2008144053A - Composite fine particles and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite fine particle comprising a fine particle core and a non-linear polysiloxane surface layer having a glass transition temperature of 30 ° C. or higher and containing no organic solvent and having reduced cohesiveness and stickiness.
SOLUTION: A non-linear polysiloxane having a glass transition temperature of 30 ° C. or more formed by solubilizing in supercritical carbon dioxide or liquefied carbon dioxide and then removing the supercritical carbon dioxide or liquefied carbon dioxide. Composite fine particles comprising a surface layer and a fine particle core insoluble in both supercritical carbon dioxide and liquefied carbon dioxide.
[Selection figure] None

Description

 The present invention relates to composite fine particles comprising a fine particle core and a non-linear polysiloxane surface layer, and a method for producing the same.

  It is known to treat the surface with a silane coupling agent in order to reduce the cohesiveness of the fine particles or improve the dispersibility. For example, in JP-A-8-245835, an organic solvent is removed after contacting with silica particles in a silane coupling agent diluted solution in which a hydrolyzable group of a silane coupling agent is not hydrolyzed. A method of drying and heat-treating as necessary has been proposed. Japanese Patent Application Laid-Open No. 10-36705 proposes a method in which inorganic particles are dispersed in a polar organic solvent, mixed with a hydrolyzed solution of a silane coupling agent, and then spray-dried.

  However, these methods require a process such as heat treatment in order to remove the organic solvent, and there are problems that the manufacturing process becomes complicated and the manufacturing cost increases. Further, even fine particles that have undergone such a process have a problem that a trace amount of an organic solvent remains and its use is limited.

  As a method for treating the surface of fine particles without using such an organic solvent, a method using high-pressure carbon dioxide is known. For example, in JP-A-2002-206028, after adding fine particles and a fluorine-based polymer compound and / or a silicone-based polymer compound to supercritical carbon dioxide or liquefied carbon dioxide, the resulting mixture is expanded under reduced pressure. Thus, a method for producing composite fine particles has been proposed. Japanese Patent Application Laid-Open No. 2002-210356 proposes a method for producing composite fine particles by removing carbon dioxide after mixing fine particles and silicones in supercritical carbon dioxide or liquefied carbon dioxide.

In these methods, there is no fear that the organic solvent remains in the composite fine particles, but JP-A-2002-206028 and JP-A-2002-210356 disclose only the use of linear polysiloxane. A linear polysiloxane is not disclosed, and composite fine particles obtained using the linear polysiloxane have problems of agglomeration and stickiness.
JP-A-8-245835 Japanese Patent Laid-Open No. 10-36705 JP 2002-206028 A JP 2002-210356 A

  An object of the present invention is to obtain composite fine particles having a core of fine particles and a surface layer of a non-linear polysiloxane having a glass transition temperature of 30 ° C. or more and containing no organic solvent and having reduced cohesiveness and stickiness. And to establish a manufacturing method thereof.

  The above object is to form a non-linear polysiloxane having a glass transition temperature of 30 ° C. or higher formed by solubilizing in supercritical carbon dioxide or liquefied carbon dioxide and then removing supercritical carbon dioxide or liquefied carbon dioxide. And a composite fine particle comprising a core of fine particles insoluble in both supercritical carbon dioxide and liquefied carbon dioxide.

The non-linear polysiloxane has an average unit formula:
R _a SiO _{(4-a) / 2}
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and a represents a number of 0.7 to 1.8)
The thing represented by these is preferable.

The non-linear polysiloxane has an average unit formula:
(R ₃ SiO _1/2 ) _b (R ₂ SiO _2/2 ) _c (RSiO _3/2 ) _d (SiO _4/2 ) _e
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and b, c, d, and e are 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5, and 0 ≦ d, respectively. ≦ 1.0, 0 ≦ e ≦ 0.8, d + e ≧ 0.3, b + c + d + e = 1)
The thing represented by these is preferable.

  Further, the non-linear polysiloxane is preferably one in which at least one R is a phenyl group in one molecule.

  The non-linear polysiloxane is preferably one in which at least one R is a fluorine atom-substituted hydrocarbon group in one molecule.

  The average particle diameter of the fine particles is preferably 0.01 to 100 μm.

  The fine particles are preferably inorganic fine particles, particularly preferably metal fine particles.

  The composite fine particles of the present invention include fine particles that are insoluble in both supercritical carbon dioxide and liquefied carbon dioxide, and non-linear particles that are solubilized in supercritical carbon dioxide or liquefied carbon dioxide and have a glass transition temperature of 30 ° C. or higher. It can be produced by removing supercritical carbon dioxide or liquefied carbon dioxide after contacting the fibrous polysiloxane.

  Since the composite fine particles of the present invention have a non-linear polysiloxane in the surface layer, the cohesiveness of the fine particles is suppressed, and the dispersibility in various hydrophobic polymer materials is good. Further, since the surface layer portion is a non-linear polysiloxane, there is little stickiness despite good slipperiness.

  Furthermore, the composite fine particles of the present invention are characterized by high safety and excellent storage stability because no volatile compounds such as organic solvents are used in the production process.

  In addition, since the supercritical carbon dioxide or liquefied carbon dioxide to be used is non-toxic, the method for producing composite fine particles of the present invention is harmless to the human body and does not discharge volatile compounds such as organic solvents. Is also small.

  In the composite fine particles of the present invention, the non-linear polysiloxane forming the surface layer includes a trifunctional siloxane unit (T unit) and / or a tetrafunctional siloxane unit (Q unit). It contains a monofunctional siloxane unit (M unit) and / or a bifunctional siloxane unit (D unit). Such a non-linear polysiloxane has a branched structure or a crosslinked structure, and is preferably a silicone resin having a high degree of branching or crosslinking.

  The glass transition temperature of the non-linear polysiloxane is 30 ° C. or higher, preferably in the range of 35 to 200 ° C., more preferably in the range of 40 to 200 ° C., and particularly preferably 50 Within the range of ~ 160 ° C. This is because if the glass transition temperature of the non-linear polysiloxane is less than the lower limit of the above range, the resulting composite fine particles are likely to aggregate and the handling workability thereof may be reduced. The glass transition temperature can be measured by using a DSC (differential scanning calorimeter).

  The molecular weight of the non-linear polysiloxane is not particularly limited, but a low molecular weight is preferred. Specifically, the weight average molecular weight is preferably in the range of 500 to 100,000, more preferably in the range of 500 to 50,000, and particularly preferably in the range of 1000 to 20000. . The weight average molecular weight can be calculated as a relative value to standard polystyrene by gel permeation chromatography.

Such non-linear polysiloxanes have an average composition formula:
R _a SiO _{(4-a) / 2}
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and a represents a number of 0.7 to 1.8)
What is represented by these can be used conveniently.

In the formula, examples of the unsubstituted hydrocarbon group for R include an alkyl group, an alkenyl group, an aralkyl group, and an aryl group. As the alkyl group _is preferably a C 1 _{-C 12} alkyl _group, C 1 -C ₆ alkyl is more preferable. Examples of the C ₁ -C ₆ alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, and a hexyl group, and a methyl group is particularly preferable. Further, as the alkenyl group _is preferably C 2 _{-C 12} alkenyl _group, C 2 -C ₆ alkenyl group is more preferable. As the C ₂ -C ₆ alkenyl group, a vinyl group, propenyl group, butenyl group, hexenyl group and the like, in particular, a vinyl group is preferred. Further, as the aralkyl group _is preferably C 7 _{-C 12} aralkyl _group, C 7 _{-C 12} aralkyl group is more preferable. Examples of the C ₇ -C ₁₂ aralkyl group include a benzyl group and a phenethyl group, and a benzyl group is particularly preferable. Also, as the aryl group, preferably a C ₆ -C ₁₂ alkenyl group, a phenyl group, a naphthyl group, and a tolyl group, especially phenyl group.

In the substituted hydrocarbon group represented by R in the formula, examples of the substituent include halogen such as fluorine atom, chlorine atom, bromine atom and iodine atom; hydroxyl group; methoxy group, ethoxy group, n-propoxy group and isopropoxy group. C ₁ -C ₆ alkoxy groups such as: amino group; amide group; nitro group; epoxy group and the like. Halogen is preferable, and fluorine atom is particularly preferable. Therefore, it is particularly preferable that the non-linear polysiloxane contains a fluorine atom. In this case, the weight fraction of fluorine atoms relative to the total weight of the non-linear polysiloxane is preferably 1 to 40% by weight, 20 weight% is more preferable and 3 to 20 weight% is more preferable. In addition, the fluorine atom is a non-linear polyoxy group such as a fluoroalkyl group such as 3,3,3-trifluoropropyl group or nonafluorobutylethyl group, or a fluoroaryl group such as 4-trifluoromethylphenyl group. It can bond to a silicon atom in the siloxane.

  In the formula, a represents a number of 0.7 to 1.8.

Further, as the non-linear polysiloxane, the average unit formula:
(R ₃ SiO _1/2 ) _b (R ₂ SiO _2/2 ) _c (RSiO _3/2 ) _d (SiO _4/2 ) _e
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and b, c, d, and e are 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5, and 0 ≦ d, respectively. ≦ 1.0, 0 ≦ e ≦ 0.8, d + e ≧ 0.3, b + c + d + e = 1)
What is represented by these can be used conveniently.

In the formula, examples of the unsubstituted hydrocarbon group for R include an alkyl group, an alkenyl group, an aralkyl group, and an aryl group, and specific examples thereof include the same groups as described above. In addition, examples of the substituent in the substituted hydrocarbon group for R include halogen such as fluorine atom, chlorine atom, bromine atom and iodine atom; hydroxyl group; C ₁ − such as methoxy group, ethoxy group, n-propoxy group and isopropoxy group. C ₆ alkoxy group; an amino group; amide group; a nitro group; an epoxy group and the like, halogens are preferred, in particular, fluorine atom is preferable. Therefore, it is particularly preferable that the non-linear polysiloxane contains a fluorine atom. In that case, the weight fraction of fluorine atoms relative to the total weight of the non-linear polysiloxane is preferably 1 to 40% by weight, 20 weight% is more preferable and 3 to 20 weight% is more preferable. In addition, the fluorine atom is a non-linear polyoxy group such as a fluoroalkyl group such as 3,3,3-trifluoropropyl group or nonafluorobutylethyl group, or a fluoroaryl group such as 4-trifluoromethylphenyl group. It can bond to a silicon atom in the siloxane.

  On the other hand, the fine particles constituting the core of the composite fine particles of the present invention are not particularly limited as long as they are insoluble in both supercritical carbon dioxide and liquefied carbon dioxide. This is because supercritical carbon dioxide or liquefied carbon dioxide is used when producing the composite fine particles of the present invention, but it is required that the shape and form thereof do not change.

  The fine particles are preferably inorganic fine particles. Examples of the material constituting the inorganic fine particles include metal oxides such as silica, titanium oxide, zirconium oxide, zinc oxide, magnesium oxide, iron oxide, zeolite, mica, talc, kaolin, sericite, antigolite, montmorillonite. Natural minerals such as carbon, carbons such as carbon black, and metals such as aluminum, zinc, chromium, iron, titanium, magnesium, copper, tin, nickel, and silver. The fine particles may be composed of one kind of these materials, or may be composed of two or more kinds of these materials. In particular, the fine particles are preferably metal fine particles.

  The average particle size of the fine particles is not particularly limited, but is preferably in the range of 0.01 to 100 μm, more preferably in the range of 0.05 to 100 μm, and particularly preferably 0.05 to 50 μm. Is within the range.

Next, the method for producing composite fine particles of the present invention will be described.
The composite fine particles of the present invention include fine particles that are insoluble in both supercritical carbon dioxide and liquefied carbon dioxide, and non-linear particles that are solubilized in supercritical carbon dioxide or liquefied carbon dioxide and have a glass transition temperature of 30 ° C. or higher. After contacting the polysiloxane, supercritical carbon dioxide or liquefied carbon dioxide is removed.

  Supercritical carbon dioxide refers to carbon dioxide under conditions of a temperature higher than the critical temperature and higher than the critical pressure, and has a property that the density changes suddenly by a slight pressure change. Then, when the pressure of supercritical carbon dioxide slightly exceeding the critical temperature is increased, the density rapidly increases, so that the solubility of the solute rapidly increases in the region exceeding the critical pressure. Conversely, when supercritical carbon dioxide is depressurized, the solubility of the solute can be drastically lowered due to the expansion of carbon dioxide, so that the solute and supercritical carbon dioxide can be separated only by the depressurization operation.

  The temperature at the start of supercritical carbon dioxide removal is preferably 31 to 250 ° C, more preferably 35 to 200 ° C, and still more preferably 35 to 150 ° C, from the viewpoint of efficiently performing decompression expansion of supercritical carbon dioxide. is there. In addition, the pressure of supercritical carbon dioxide at the start of removal is preferably 7.4 to 40 MPa, more preferably 10 to 30 MPa in order to efficiently perform decompression expansion of supercritical carbon dioxide.

  The method for removing supercritical carbon dioxide is arbitrary and is not particularly limited. For example, the mixture of the non-linear polysiloxane, the fine particles, and the supercritical carbon dioxide is discharged from a nozzle having a predetermined diameter at normal temperature and normal temperature. It can be carried out by a method of ejecting under pressure or a method of depressurizing a container containing the mixture.

  The speed of the depressurization can be appropriately adjusted according to the pressure of supercritical carbon dioxide, the volume of the container, and the size of the carbon dioxide exhaust port. As an example, when the pressure at the start of decompression is 25 MPa, the container volume is 500 mL, and the exhaust port diameter is 0.1 mm, the pressure can be returned to normal pressure in about 1 hour.

  In the present invention, liquefied carbon dioxide can also be used. Also in this case, when the pressure of liquefied carbon dioxide is reduced, the solubility of the solute in carbon dioxide can be drastically reduced, so that the solute and carbon dioxide can be separated only by a pressure reduction operation. The temperature at the start of depressurization of liquefied carbon dioxide is preferably −40 to 30 ° C., more preferably 0 to 30 ° C. from the viewpoint of efficiently performing depressurization and expansion of liquefied carbon dioxide. In addition, the pressure of the liquefied carbon dioxide at the start of decompression is preferably 1 to 40 MPa, more preferably 3.5 to 40 MPa, in order to efficiently decompress the liquefied carbon dioxide.

  In terms of being able to dissolve a larger amount of solute, it is preferable to use supercritical carbon dioxide rather than liquefied carbon dioxide.

  The concentration of the non-linear polysiloxane dissolved in supercritical carbon dioxide or liquefied carbon dioxide is not particularly limited, but can be, for example, in the range of 0.01 to 50% by weight, and preferably is 0.1. It is 02-40 weight%, More preferably, it is 0.03-30 weight%.

  Further, the ratio of the non-linear polysiloxane to the fine particles in the composite fine particles is not particularly limited. Usually, the fine particles are in the range of 0.1 to 1000 parts by weight, preferably in the range of 1 to 1000 parts by weight, particularly preferably 1 to 1 part by weight of the non-linear polysiloxane. An amount in the range of ˜500 parts by weight.

  The material of the container used in the method for producing composite fine particles of the present invention may be any material that can withstand the temperature and pressure used, and known materials such as stainless steel and glass can be used. Examples of the container include an autoclave having an exhaust port such as a valve for performing a pressure reduction operation, a pressure cell, and the like. The shape and size are not limited. Further, in order to dissolve and disperse the non-linear polysiloxane in carbon dioxide, those having a stirring mechanism in the container are preferable.

  In the method for producing composite fine particles of the present invention, carbon dioxide is harmless and no liquid substance having a boiling point of 250 ° C. or lower is used at all, so that adverse effects on the human body can be eliminated. In addition, since no special apparatus is used other than the apparatus for adjusting the pressure and temperature of carbon dioxide, composite fine particles can be obtained with a simple system.

  In addition, when supercritical carbon dioxide or liquefied carbon dioxide is used, the operation can be performed at a low temperature. Therefore, the operation is easy, and since carbon dioxide is inexpensive, the manufacturing cost can be reduced. There is also an advantage of being able to do it.

An example of the production apparatus for composite fine particles of the present invention is shown in FIG.
In FIG. 1, carbon dioxide passes from the tank 1 through the liquefier 2 and is supplied into the container 6 through the pipe 5. Carbon dioxide supplied into the container 6 is maintained at a predetermined temperature and pressure by the heater 4a and the high-pressure pump 3. In FIG. 1, P1 is a pressure gauge for detecting the pressure of carbon dioxide, V1 is a valve of the tank 1, and V2 is a stop valve for avoiding a backflow in the pipe 5.

  The container 6 is provided with pipes 7a and 7b for supplying non-linear polysiloxane and core fine particles, and the non-linear polysiloxane and fine particles are independently supplied from the supply source (not shown) through the pipes 7a and 7b. Into the container 6. In FIG. 1, V4a and V4b are stop valves for avoiding backflow in the pipes 7a and 7b.

  In the container 6, carbon dioxide, non-linear polysiloxane, and fine particles supplied from the pipe 5 and the pipes 7a and 7b are mixed. A stirrer 8 is provided in the container 6, and it is possible to stir the carbon dioxide, non-chain polysiloxane, and fine particles in the container 6 to obtain a uniform mixture of carbon dioxide and non-chain polysiloxane. is there. In addition, a thermometer T is installed in the container 6, and a jacket 9 for adjusting the temperature is disposed around the container 6, and a thermal refrigerant having a predetermined temperature is supplied into the jacket 9 from a supply source (not shown). By introducing, the temperature in the container 6 can be adjusted. In FIG. 1, P2 is a pressure gauge for detecting the pressure in the container 6.

  The container 6 is provided with a carbon dioxide exhaust pipe 10 provided with a heater 4b and a nozzle 11 having a predetermined diameter. In FIG. 1, V3 is a stop valve for avoiding backflow in the pipe 10. The nozzle 11 includes a temperature adjusting device (not shown), and the temperature of the nozzle 11 is maintained within a predetermined range.

  In the case of producing composite fine particles using the apparatus shown in FIG. 1, carbon dioxide in a supercritical state is supplied from the tank 1 into the container 6 through the pipe 5, while non-linear is supplied from a supply source (not shown). The polysiloxane and the fine particles are supplied into the container 6 independently through the pipes 7a and 7b. In the container 6, a mixing operation is performed at a predetermined temperature with a stirrer 8 and a jacket 9 to dissolve the non-linear polysiloxane in supercritical carbon dioxide. After the non-linear polysiloxane is completely dissolved in supercritical carbon dioxide, the carbon dioxide is discharged through the pipe 10 to obtain composite fine particles from the container 6. Alternatively, composite fine particles can be obtained by ejecting the mixture in the container 6 from the nozzle 11 via the pipe 10.

  The temperature of the heaters 4a, 4b, the jacket 9, and the nozzle 11 is not particularly limited as long as the temperature can maintain the supercritical state of carbon dioxide, but is preferably in the range of 40 to 150 ° C, preferably 40 to 100 ° C. Is more preferable. Further, the internal pressures of the pipe 5, the pipes 7a and 7b, the pipe 10, the container 6, and the nozzle 11 are not particularly limited as long as the supercritical state of carbon dioxide can be maintained, but is 10 to 40 MPa. Is preferable, and 15-30 MPa is more preferable.

  The composite fine particles of the present invention may contain an optional component other than the non-linear polysiloxane. Examples of such components include fillers, antioxidants, ultraviolet absorbers, and colorants. These optional components may be used alone or in combination of two or more. The optional component can be contained in the fine particles by dissolving in supercritical carbon dioxide or liquefied carbon dioxide. The composite fine particles of the present invention have desired properties such as water repellency, oil repellency, optical properties, UV protection, touch, safety, color tone, weather resistance, etc. Can be granted.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to an Example. The apparatus shown in FIG. 1 was used for the production of the composite particles. A high-pressure dissolution tank having a capacity of 330 ml was used as the container 6, the temperature of the heater 4 a and the jacket 9 was 40 ° C., the temperature of the heater 4 b and the nozzle 11 was 100 ° C., and the internal pressure was 15.0 MPa. The inner diameter of the nozzle 11 was 0.1 mm.

  The weight average molecular weight of the non-linear polysiloxane (hereinafter simply referred to as “average molecular weight”) was calculated as a relative value with respect to standard polystyrene using chloroform as an eluent by HLC-8020 manufactured by Tosoh Corporation.

  Agglomeration of the composite fine particles was performed by morphological observation using a scanning electron microscope JSM-5800LV manufactured by JEOL Ltd. Further, the stickiness of the composite fine particles was placed in a glass vial and visually observed.

  Furthermore, the thermogravimetric analysis of the composite fine particles was carried out using a thermogravimetry measuring apparatus TGA-50 manufactured by Shimadzu Corporation, and the ratio of the weight of the residue after heating up to 800 ° C. at a rate of 10 ° C./min in air %).

[Example 1]
10 g of silver particles having an average particle diameter of 5 μm as core fine particles, and an average molecular weight of 3000 as non-linear polysiloxane and an average composition formula:
(C ₃ H ₄ F ₃ ) _0.4 (C ₆ H ₅ ) _0.5 (CH ₃ ) _0.3 SiO _1.4
Also represented by the average unit formula:
[(CH ₃ ) ₂ SiO _2/2 ] _0.2 (C ₆ H ₅ SiO _3/2 ) _0.4 (C ₃ H ₄ F ₃ SiO _3/2 ) _0.4
The fluorine-modified silicone resin 0.1g represented by these was used. These substrates are supplied independently from the pipe 7 into the container 6, and then carbon dioxide in a supercritical state at a temperature of 40 ° C. and a pressure of 15 MPa is supplied from the pipe 5 into the container 6 and stirred for 1 hour. The fluorine-modified silicone resin was completely dissolved. Carbon dioxide was removed from the nozzle 11 through the pipe 10 from the obtained mixture over 1 hour, and the composite fine particles in the container 6 were recovered.

  The scanning electron microscope image of the obtained composite fine particles showed no difference compared to the image of the particles before complexing with the non-linear polysiloxane. This result shows that the surface of the silver particles used is uniformly coated with the non-linear polysiloxane and the microscopic aggregation of the silver particles as the core does not occur.

  Part of the obtained composite fine particles was placed in a 10 mL glass vial and visually observed. Aggregation between individual particles was not observed, and even when shaken, it did not stick to the inner wall of the vial.

  As a result of thermogravimetric analysis of the composite fine particles, the residual weight was 99.0%.

[Example 2]
A composite fine particle was obtained in the same manner as in Example 1 except that the amount of the non-linear polysiloxane was changed to 0.5 g. As a result of visual observation of the composite fine particles, aggregation between the individual particles was not observed, and even when shaken, they did not adhere to the inner wall of the vial.

[Example 3]
Non-linear polysiloxane with an average molecular weight of 2700 and an average composition formula:
(C ₆ H ₅ ) _0.8 (CH ₃ ) _0.4 SiO _1.4
Also represented by the average unit formula:
[(CH ₃ ) ₂ SiO _2/2 ] _0.2 (C ₆ H ₅ SiO _3/2 ) _0.8
A composite fine particle was obtained in the same manner as in Example 1 except that 0.1 g of the silicone resin represented by the formula (1) was used. As a result of visual observation of the composite fine particles, aggregation between the individual particles was not observed, and even when shaken, they did not adhere to the inner wall of the vial.

[Comparative Example 1]
Uncomposited silver particles were placed in a glass vial and visually observed. Upon shaking, some particles adhered to the inner wall of the vial.

[Comparative Example 2]
Instead of non-linear polysiloxane, average molecular weight 3000 and average composition formula:
(C ₆ H ₅ ) _0.9 (CH ₃ ) _1.2 SiO _0.95
Also represented by the average unit formula:
(CH ₃ ) ₃ SiO [C ₆ H ₅ (CH ₃ ) SiO] ₂₀ Si (CH ₃ ) ₃
In the same manner as in Example 1 except that a linear polysiloxane represented by the following formula was used, composite fine particles were obtained. As a result of visual observation of the composite fine particles, no aggregation between the individual particles was observed, but when it was shaken, it adhered to the inner wall of the vial.

  The composite fine particles of the present invention do not have a sticky feeling despite being imparted with good slipperiness, and contain no volatile compounds such as organic solvents and are highly safe. It is useful for agents, additives for resin films, cosmetics applications and the like.

The figure which shows an example of the manufacturing apparatus of the composite fine particle of this invention

Explanation of symbols

  1: tank, 2: liquefier, 3: high pressure pump, 4a, 4b: heater, 5: piping for supplying carbon dioxide, 6: container, 7a, 7b: piping for supplying non-linear polysiloxane and core fine particles, 8 : Stirrer, 9: Jacket, 10: Piping, 11: Nozzle

Claims (16)

  A surface layer of a non-linear polysiloxane having a glass transition temperature of 30 ° C. or higher, formed by solubilizing in supercritical carbon dioxide or liquefied carbon dioxide and then removing supercritical carbon dioxide or liquefied carbon dioxide; Composite fine particles composed of fine particle cores that are insoluble in both supercritical carbon dioxide and liquefied carbon dioxide. Non-linear polysiloxane has an average composition formula:
R _a SiO _{(4-a) / 2}
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and a represents a number of 0.7 to 1.8)
The composite fine particle according to claim 1, represented by: Non-linear polysiloxane has an average unit formula:
(R ₃ SiO _1/2 ) _b (R ₂ SiO _2/2 ) _c (RSiO _3/2 ) _d (SiO _4/2 ) _e
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and b, c, d, and e are 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5, and 0 ≦ d, respectively. ≦ 1.0, 0 ≦ e ≦ 0.8, d + e ≧ 0.3, b + c + d + e = 1)
The composite fine particle according to claim 1, represented by:   The composite fine particle according to claim 2 or 3, wherein at least one of R in one molecule is a phenyl group.   The composite fine particle according to claim 2 or 3, wherein at least one R is a fluorine atom-substituted hydrocarbon group in one molecule.   The composite fine particles according to any one of claims 1 to 5, wherein an average particle size of the fine particles is 0.01 to 100 µm.   The composite fine particle according to any one of claims 1 to 6, wherein the fine particle is an inorganic fine particle.   The composite fine particle according to claim 7, wherein the inorganic fine particle is a metal fine particle.   Fine particles insoluble in both supercritical carbon dioxide and liquefied carbon dioxide were brought into contact with non-linear polysiloxane solubilized in supercritical carbon dioxide or liquefied carbon dioxide and having a glass transition temperature of 30 ° C. or higher. 2. The method for producing composite fine particles according to claim 1, wherein supercritical carbon dioxide or liquefied carbon dioxide is subsequently removed. Non-linear polysiloxane has an average composition formula:
R _a SiO _{(4-a) / 2}
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and a represents a number of 0.7 to 1.8)
The manufacturing method of the composite microparticle of Claim 9 represented by these. Non-linear polysiloxane has an average unit formula:
(R ₃ SiO _1/2 ) _b (R ₂ SiO _2/2 ) _c (RSiO _3/2 ) _d (SiO _4/2 ) _e
(In the formula, R represents a monovalent substituted or unsubstituted hydrocarbon group, and b, c, d, and e are 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5, and 0 ≦ d, respectively. ≦ 1.0, 0 ≦ e ≦ 0.8, d + e ≧ 0.3, b + c + d + e = 1)
The manufacturing method of the composite microparticle of Claim 9 represented by these.   The method for producing composite fine particles according to claim 10 or 11, wherein at least one of R in one molecule is a phenyl group.   The method for producing composite fine particles according to claim 10 or 11, wherein at least one R in one molecule is a fluorine atom-substituted hydrocarbon group.   The method for producing composite fine particles according to any one of claims 9 to 13, wherein the average particle size of the fine particles is 0.01 to 100 µm.   The method for producing composite fine particles according to any one of claims 9 to 13, wherein the fine particles are inorganic fine particles.   The method for producing composite fine particles according to claim 15, wherein the inorganic fine particles are metal fine particles.

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