JP2006232982A - Surface-coated flame-retardant particle and its manufacturing method, and flame-retardant resin composition and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new flame-retardant resin composition hardly suffering from lowering of mechanical physical properties and having a light environmental load, a surface-coated flame-retardant particle used therefor, and a manufacturing method of these. <P>SOLUTION: The surface-coated flame-retardant particle comprises a flame-retardant particle, which is comprised of a hydrate of a metal selected from among Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni and has a volume-average particle size within the range of 1-500 nm, and, formed on the surface thereof, a coating layer containing a polyamino acid or a polysilicone. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to surface-coated flame-retardant particles, a flame-retardant resin composition using the same, and methods for producing the same, and more specifically, housings, electric wires, and cables for home appliances and OA products, It is used for the purpose of protecting automobile vehicles, ships, airplanes, railway vehicles, building materials, electronic devices, printed boards, etc. from disasters caused by heat such as fire.

  As flame retardants used for the purpose of making flame retardant by mixing with matrix resin (hereinafter sometimes referred to simply as “resin”), halogen compounds, antimony trioxide, phosphorus compounds, hydrated metal compounds have been conventionally used. (Metal hydrates) are used. Among these, the halogen compounds and antimony trioxide generate harmful substances during combustion, and are being avoided from environmental problems, while the hydrated metal compounds not only reduce the environmental burden, but also from the viewpoint of resin recycling. Is also preferable because of its superiority.

  However, since the hydrated metal compound requires a large amount of blending in order to obtain the same flame retardancy as compared with other organic flame retardant compounds, the physical properties of the polymer are significantly lowered. In order to obtain the same flame retardance as the other organic flame retardant compounds without deteriorating the polymer properties, hydrated metal compounds with a small particle size are dispersed in single particle units without agglomerating in the matrix resin. Must be stabilized. For this reason, when mixing particles made of metal hydrate into the resin, it is necessary to form a uniform coating layer having high affinity with the resin on the particle surface in order to ensure dispersibility in the matrix resin. .

  As a method for forming a coating layer on the particle surface, first, surface treatment with a higher fatty acid or the like, formation of a silica layer, etc. are known (for example, see Patent Documents 1 and 2). Under these reaction conditions, the particles are not sufficiently dispersed and the coating reaction rate is fast, so that the particles undergo a coating reaction in an aggregated state, and as a result, uniform coated particles cannot be obtained.

  In addition, there are methods of treating the surface of the inorganic powder with a polyamino acid or a gas phase cyclic organosiloxane (see, for example, Patent Documents 3 and 4). When applied, dispersibility is not ensured and aggregates are generated.

Furthermore, in recent years, polymer nanocomposite compositions of polyamide and treated silicates and polycarbonate blends containing graft polymers, phosphonate amines and inorganic nanoparticles have been proposed as examples of resin flame retardant using fine particles. However, when both are used as a flame retardant, the above problems are not solved.
JP-A-52-30262 JP 2003-253266 A JP 57-145006 A JP-A-61-268763 JP 2003-517488 A JP 2003-509523 A

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, the present invention aims to provide a novel flame retardant resin composition with little deterioration in mechanical physical properties and less environmental burden, surface-coated flame retardant particles used therefor, and a method for producing them. And Specifically, the flame retardant fine particles necessary for obtaining a novel inorganic flame retardant that provides the same flame retardancy as compared with the organic flame retardant compound and does not significantly reduce the physical properties of the polymer. The purpose is to provide a manufacturing method thereof.

  Conventional flame retardants have been studied to make the resin flame-retardant by blending flame retardant particles having a particle diameter of 1 to 50 μm in a large amount of at least about 50 to 150 parts by mass with respect to 100 parts by mass of the matrix resin. I came. Since such a large amount of particles deteriorates the mechanical characteristics and electrical characteristics of the resin, prescriptions such as mixing other additives or other resins have been adopted.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research on the formation of flame retardant particles that increase the specific surface area of the particles and increase the contact area with the polymer. And a manufacturing method thereof. The flame retardant particles obtained thereby have not only a volume average particle diameter in the range of 1 to 500 nm, but also a polyamino acid or a silicone having an organic group capable of binding to the inorganic fine particles on the surface of the inorganic fine particles. Since these are surface-coated flame retardant particles arranged as a uniform layer, when these are blended with a polymer, the volume average particle size is about 0.5 to 50 μm, compared with a flame retardant compound having a low filling and equivalent. It was confirmed that flame retardancy was possible.

That is, the present invention
<1> Flame retardant particles comprising a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni and having a volume average particle diameter in the range of 1 to 500 nm The surface-coated flame-retardant particles are characterized in that a coating layer containing a polyamino acid or a polysilicone is formed on the surface of the surface-coated flame retardant.

<2> Flame retardant comprising at least one metal hydrate selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni and having a volume average particle diameter in the range of 1 to 500 nm. A flame-retardant resin composition comprising surface-coated flame-retardant particles in which a coating layer containing a polyamino acid or poly-silicone is formed on the surface of the conductive particles, in a matrix resin.

<3> At least in the aqueous solution in which the dispersant is dissolved, the volume average particle diameter is made of a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni. A step of preparing a dispersion by dispersing flame retardant particles in the range of 1 to 500 nm, and a polyamino acid salt aqueous solution is dropped into the dispersion to deposit a polyamino acid on the surface of the flame retardant particles to form a coating layer A process for forming surface-coated flame-retardant particles.

<4> Flame retardant particles comprising a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni and having a volume average particle diameter in the range of 1 to 500 nm. A method for producing surface-coated flame-retardant particles, characterized in that a vaporized product of a cyclic organosiloxane compound is allowed to act on the surface of the flame-retardant particles to form a coating layer by ring-opening polymerization of the cyclic organosiloxane compound. It is.

<5> Surface-coated flame-retardant particles produced by the method for producing surface-coated flame-retardant particles according to <3> or <4>.

<6> At least the matrix resin and the surface-coated flame-retardant particles are mixed and kneaded in one or more kneaders selected from a roll, a kneader, a Banbury mixer, an intermix, a single screw extruder, and a twin screw extruder. A method for producing a flame retardant resin composition, comprising:
The surface-coated flame-retardant particles are made of a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni, and have a volume average particle diameter of 1 to 500 nm. This is a method for producing a flame-retardant resin composition, which is a surface-coated flame-retardant particle in which a coating layer containing a polyamino acid or a polysilicone is formed on the surface of the flame-retardant particle.

  According to the present invention, surface-coated flame-retardant particles having a uniform coating layer having a large specific surface area of particles and a large contact area with a polymer, a flame-retardant resin composition using the same, and a method for producing the same Can be provided.

Hereinafter, the present invention will be described in detail.
<Surface coated flame retardant particles>
The surface-coated flame-retardant particles of the present invention are composed of a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni, and have a volume average particle diameter of 1 to 500 nm. A coating layer containing a polyamino acid or a polysilicone is formed on the surface of the flame retardant particles in the range of the above.

  As described above, in order to improve the dispersibility of the nano-sized flame retardant particles in the resin, it is effective to form a uniform coating layer on the surface of the flame retardant particles. In the surface-coated flame-retardant particles of the present invention, hydration of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni as the flame-retardant particles on which the coating layer is formed. Use things. These metal hydrates can be easily made into fine particles and are not only stable as hydrates, but also exhibit excellent flame retardant effects due to excellent heat absorption and dehydration reactivity upon heating. Among the above metal hydrated compounds, hydrates of Mg, Al, and Ca are particularly preferable.

  The metal hydrate is not particularly limited as long as it retains a flame retardant component. Specifically, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, iron hydroxide, zinc hydroxide, hydroxide Examples include hydrated metal compounds such as copper and nickel hydroxide; hydrates of calcium aluminate, dihydrate gypsum, zinc borate, barium metaborate, and the like. Furthermore, these complex hydrates are also preferably used. Among these, magnesium hydroxide, aluminum hydroxide, and calcium hydroxide are preferable.

  The volume average particle diameter of the flame retardant particles made of the metal hydrate is in the range of 1 to 500 nm. The volume average particle diameter of the flame retardant particles is preferably in the range of 1 to 200 nm, more preferably in the range of 5 to 200 nm, and still more preferably in the range of 10 to 200 nm.

  When the volume average particle diameter of the flame retardant particles is smaller than 1 nm, the flame retardancy retention ability is lowered. Moreover, when larger than 500 nm, it becomes a characteristic equivalent to a commercially available flame-retardant particle | grain with a volume average particle diameter of 1 micrometer, and in order to acquire a flame retardance, it will be necessary to add in large quantities.

  Further, the surface-coated flame retardant particles using the flame retardant particles having a volume average particle diameter in the above range are uniformly dispersed in the resin. Furthermore, when the volume average particle diameter of the flame retardant particles is nanometer size, coupled with the ability to form a fine composite, a highly transparent flame retardant resin composition can be obtained.

In the present invention, a coating layer containing polyamino acid or polysilicon is formed on the surface of the flame retardant particles.
Although it does not restrict | limit especially as said polyamino acid, It is preferable that it has an organic group which can couple | bond with the said flame-retardant particle | grain. By bonding such an organic group to the flame retardant particles, a thin organic layer can be uniformly formed on the surface of the flame retardant particles.

As the polyamino acid, those having a binding group for forming a bond with the flame retardant particles at the end of the organic group are preferable.
Examples of the binding group include hydroxyl group, phosphate group, phosphonium base, amino group, sulfate group, sulfonate group, carboxyl group, hydrophilic heterocyclic group, polysaccharide group (sorbitol, sorbit, sorbitan, sucrose ester , Sorbitan ester residues, etc.), polyether groups (polyoxyethylene groups such as polyoxyethylene and polyoxypropylene groups such as polyoxyalkylene groups having 2 to 4 carbon atoms), hydrolyzable groups (methoxy, ethoxy, propoxy, iso Examples thereof include an alkoxy group having 1 to 4 carbon atoms such as propoxy and butoxy groups, and a halogen atom (bromine, chlorine atom, etc.).

  When the binding group is an anionic group (sulfuric acid group, sulfonic acid group, carboxyl group, etc.), various bases and salts may be formed. Examples of the base include inorganic bases (eg, alkaline earth metals such as calcium and magnesium, alkali metals such as sodium and potassium, ammonia and the like), and organic bases (eg amines). Further, when the binding group is a cationic group (for example, an amino group), a salt may be formed with an acid such as an inorganic acid (such as hydrochloric acid or sulfuric acid) or an organic acid (such as acetic acid). Further, the cationic group may form a salt with an anionic group (particularly a carboxyl group or a sulfate group). Moreover, you may have both a cationic group and an anionic group as a bonding group.

  Thus, preferred binding groups include ionic groups (anionic groups, cationic groups) and hydrolyzable groups, and the bonds formed with the flame retardant particles are shared even if they are ionic bonds. It may be a bond.

Examples of the organic group include residues of various polyamino acids.
Examples of the polyamino acid include polyaspartic acid, polyglutamic acid, polyarginine, and polyglycine. Of these, acidic polyamino acids such as polyaspartic acid and polyglutamic acid are preferably used.
The number average molecular weight of the polyamino acid is preferably in the range of 10 to 10,000.

By forming the coating layer with the above polyamino acid, when the surface-coated flame retardant particles are mixed with the matrix resin, it is possible to make the resin less likely to be plasticized.
Further, by appropriately adjusting the coating amount of the polyamino acid coating layer and the kind / action amount of the acidic substance, the moldability (plasticity) and mechanical properties of the resin can be controlled even with the same blending amount.

  The poly-silicone is not particularly limited as long as it has a siloxane bond, but using a polymer of a cyclic organosiloxane compound represented by the following general formula (1) facilitates the reaction. Is preferable.

  In said formula, n represents the integer of 3-8. The smaller the number of n, the lower the boiling point, and the greater the amount that volatilizes and adsorbs to the flame retardant particles. When n exceeds 7, it is difficult to volatilize and the coating treatment becomes insufficient, which is not preferable. In particular, tetramer, pentamer, and hexamer are most suitable because they are easily polymerized due to their steric properties.

  In the present invention, any one of the cyclic organosiloxane compounds (a) and (b) represented by the general formula (1) or a combination of two types can be used. Further, as the coating layer, the above polymer and other resins may be used in combination.

By using the low surface energy polysilicon as described above as the coating layer, the resin is less likely to be plasticized when the surface-coated flame retardant particles are mixed with the matrix resin.
In addition, when a flame retardant resin composition is used, the surface polysilicon layer forms a thermal barrier layer during combustion, but is released from metal hydrate particles by forming a polysilicon coating layer on the particle surface. Since the generated moisture causes the thermal barrier layer to foam, the heat insulation property of the thermal barrier layer can be increased and the flame retardant effect can be improved.

The amount of the surface coating with the polyamino acid or the polysilicone in the surface-coated flame-retardant particles of the present invention is preferably in the range of 20 to 200% by mass of the entire surface-coated flame-retardant particles, and in the range of 20 to 80% by mass. More preferably. If the coating amount is less than 20% by mass, aggregates may be generated in the matrix resin, and the dispersion may become non-uniform. On the other hand, if it exceeds 200% by mass, the resin may be plasticized when dispersed in the matrix resin.
The uniformity of the coating layer can be confirmed by observing the surface-coated flame-retardant particles with a transmission electron microscope.

  Moreover, the volume average particle diameter of the surface-coated flame-retardant particles of the present invention (the average diameter of the circumscribed circle when the surface-coated flame-retardant particles are non-spherical) is preferably in the range of 1 to 500 nm. More preferably, the surface-coated flame retardant particles have a volume average particle size in the range of 1 to 200 nm, more preferably in the range of 5 to 200 nm, and particularly preferably in the range of 10 to 200 nm (particularly 10 to 100 nm).

  When the volume average particle diameter of the surface-coated flame retardant particles is smaller than 1 nm, the flame retardancy retention ability is lowered. When the volume average particle diameter is larger than 500 nm, the properties are equivalent to those of a commercially available volume average particle diameter of 1 μm, and flame retardancy is obtained. Therefore, it is necessary to add a large amount. The surface-coated flame retardant particles having a volume average particle diameter in the above range are uniformly dispersed in the resin. In addition, when the volume average particle diameter of the surface-coated flame-retardant particles is nanometer size, a highly transparent flame-retardant resin composition can be obtained in combination with the ability to form a fine composite.

The dispersion degree of the surface-coated flame retardant particles is preferably in the range of 0.1 to 3.0. The dispersity is more preferably in the range of 0.1 to 1.0, and particularly preferably in the range of 0.1 to 0.8.
A low degree of dispersion indicates that the particle size distribution of the surface-coated flame retardant particles is narrow, that is, the size of the particles is more uniform. When the degree of dispersion is in the above range, Flame retardancy and mechanical properties are also uniform.

The volume average particle size (including flame retardant particles) and the degree of dispersion were measured with a laser Doppler heterodyne type particle size distribution meter (manufactured by UPA Nikkiso Co., Ltd., MICROTRAC-UPA150) (the same applies hereinafter). Specifically, based on the measured particle size distribution, the cumulative distribution was subtracted from the small particle size side with respect to the volume, and the particle size at 50% cumulative was taken as the volume average particle size. Further, by subtracting the particle size distribution for the mass, when D ₉₀ particle size from the smaller particle size side at an accumulation of 90%, a particle size of 10% cumulative was D _10, the degree of dispersion defined by the following formula (1) Is done. This measurement method is the same below.
Dispersity = log (D ₉₀ / D ₁₀ ) Expression (1)

  The method for producing the surface-coated flame-retardant particles of the present invention is not particularly limited as long as it can satisfy the above-described configuration and characteristics, but the method for producing the surface-coated flame-retardant particles of the present invention described later is preferably used. Can be used.

<Method for producing surface-coated flame-retardant particles>
The method for producing the surface-coated flame-retardant particles of the present invention is roughly classified into two. These are the production methods of the first and second surface-coated flame retardant particles of the present invention (hereinafter, these may be referred to as “first and second present inventions” respectively), Show the contents.

(Method for producing first surface-coated flame-retardant particles)
The method for producing the first surface-coated flame-retardant particles of the present invention is at least selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni in an aqueous solution in which a dispersant is dissolved. A step of preparing a dispersion by dispersing flame retardant particles having a volume average particle diameter of 1 to 500 nm comprising a hydrate of various kinds of metals, and adding a polyamino acid salt aqueous solution dropwise to the dispersion And a step of depositing a polyamino acid on the surface of the flame retardant particles to form a coating layer.

As described above, in order to uniformly disperse the flame-retardant particles having a particle size of nano-size in the resin, it is necessary to form a uniform coating layer on the particle surface. According to the first method for producing surface-coated flame-retardant particles, a polyamino acid coating layer can be formed uniformly and with good controllability on the surface of nano-sized particles made of metal hydrate and having a large surface area. . In particular, when the polyamino acid is coated on the surface of the flame retardant particles by this production method, the coating can be performed in the presence of a dispersant, so that the reaction becomes slower and a uniform coating layer can be obtained.
In the first aspect of the present invention, the flame-retardant particles made of metal hydrate can be easily dispersed, and the stability of the hydrate is high. Can be increased.

Hereinafter, first, about the 1st surface covering flame-retardant particle | grains, the manufacturing method is demonstrated about each process.
(Process for producing dispersion)
In this step, flame retardant particles made of a hydrate of a specific metal are dispersed in an aqueous solution in which an organic compound metal salt and a dispersant are dissolved.

  The dispersant is not particularly limited as long as it is a dispersant that dissolves in water and improves the dispersibility of the flame-retardant particles described below, but a polymer dispersant or sodium polyphosphate is preferably used. As the polymer dispersant, polyvinyl alcohol, polyvinyl-2-pyrrolidone, polypropylcellulose, polyacrylic acid and the like are preferable. The molecular weight of the polymer dispersant is preferably in the range of 100 to 10,000 in terms of volume average molecular weight in terms of styrene. When the volume average molecular weight is less than 100, the flame retardant particles may not be sufficiently dispersed in the reaction solution, and the coating reaction may be uneven. When the volume average molecular weight exceeds 10,000, the polymer dispersant aggregates on the surface of the flame retardant particles, and the dispersibility of the flame retardant particles in the reaction solution is lowered, and the coating reaction is not uniformly performed. There is.

In 1st this invention, the aqueous solution which dissolved the said dispersing agent in water is prepared as a solution used for the surface treatment of the flame-retardant particle | grains mentioned later. The concentration of the dispersant in the aqueous solution is preferably within a certain range from the viewpoint of uniformly covering the entire surface of the flame retardant particles.
Specifically, the concentration of the dispersant is preferably in the range of 1 to 10% by mass and more preferably in the range of 2 to 5% by mass with respect to the amount of flame retardant particles described below. If the concentration of the dispersant is less than 1% by mass, the dispersibility of the flame retardant particles in the reaction solution may be reduced, and the coating reaction may not be performed uniformly. In some cases, the concentration of the liquid becomes high and the coating reaction is not performed uniformly.

Next, the flame retardant particles dispersed in the aqueous solution will be described.
The flame retardant particles in the present invention are composed of one type of metal hydrate selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni. These metal hydrates can be easily made into fine particles and are not only stable as hydrates, but also exhibit excellent flame retardant effects due to excellent heat absorption and dehydration reactivity upon heating. Among the above metal hydrated compounds, hydrates of Mg, Al, and Ca are particularly preferable.

  The metal hydrate is not particularly limited as long as it retains a flame retardant component. Specifically, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, iron hydroxide, zinc hydroxide, hydroxide Examples include hydrated metal compounds such as copper and nickel hydroxide; hydrates of calcium aluminate, dihydrate gypsum, zinc borate, barium metaborate, and the like. Furthermore, these complex hydrates are also preferably used. Among these, magnesium hydroxide, aluminum hydroxide, and calcium hydroxide are preferable.

  The volume average particle diameter of the flame retardant particles made of the metal hydrate is in the range of 1 to 500 nm. The volume average particle diameter of the flame retardant particles is preferably in the range of 1 to 200 nm, more preferably in the range of 5 to 200 nm, and still more preferably in the range of 10 to 200 nm.

  When the volume average particle diameter of the flame retardant particles is smaller than 1 nm, the flame retardancy retention ability is lowered. Moreover, when larger than 500 nm, it becomes a characteristic equivalent to a commercially available flame-retardant particle | grain with a volume average particle diameter of 1 micrometer, and in order to acquire a flame retardance, it will be necessary to add in large quantities.

  Further, the surface-coated flame retardant particles using the flame retardant particles having a volume average particle diameter in the above range are uniformly dispersed in the resin. Furthermore, when the volume average particle diameter of the flame retardant particles is nanometer size, coupled with the ability to form a fine composite, a highly transparent flame retardant resin composition can be obtained.

In order to coat the surface of the flame retardant particles with the polyamino acid, the flame retardant particles are dispersed in an aqueous solution containing the dispersant. In the present invention, the productivity of the surface-coated flame retardant particles and uniform coating are From the viewpoint of compatibility, it is preferable that the dispersion concentration of the flame retardant particles be in a certain range.
In addition, the said dispersion | distribution density | concentration is calculated | required by following formula (2).
Dispersion concentration (mass%) = (mass of flame retardant particles / mass of aqueous solution) × 100 Formula (2)

  In the first aspect of the present invention, the dispersion concentration of the flame retardant particles is preferably in the range of 0.1 to 20% by mass, and more preferably in the range of 1.0 to 20% by mass. Thus, by lowering the dispersion concentration of the flame retardant particles, it is possible to improve the dispersibility by preventing the aggregation of the particles in the dispersion medium, and form a uniform coating layer on the surface of the nano-sized particles. be able to.

  If the dispersion concentration of the flame retardant particles is less than 0.1% by mass, uniform coating may be possible, but there may be a problem in terms of productivity. On the other hand, when the dispersion concentration exceeds 5% by mass, aggregation is likely to occur in the dispersion, and uniform coating may be difficult.

  The flame retardant particles can be dispersed in the aqueous solution by using a normal stirring device or the like. If necessary, the dispersion can be made more uniform by using ultrasonic treatment with an ultrasonic disperser. A dispersion can be obtained.

(Step of forming the coating layer)
In this step, an aqueous polyamino acid salt solution is dropped into the dispersion of the flame retardant particles to deposit the polyamino acid on the surface of the flame retardant particles to form a coating layer.

The polyamino acid salt is selected from metal salts of polyamino acids that are polymers of amino acids. Examples of the polyamino acids include polyaspartic acid, polyglutamic acid, polyarginine, and polyglycine. Can be mentioned. Of these, acidic polyamino acids such as polyaspartic acid and polyglutamic acid are preferably used.
The number average molecular weight of the polyamino acid is preferably in the range of 10 to 10,000.
Moreover, sodium, potassium, lithium, etc. are used as a metal in the said metal salt.

In the present invention, the concentration of the polyamino acid salt aqueous solution is preferably in the range of 1 to 30% by mass, and more preferably in the range of 5 to 10% by mass.
If the said density | concentration is less than 1 mass%, the amount of polyamino acid salt aqueous solution dripped in a dispersion liquid will increase considerably, and productivity may not be securable. On the other hand, if the concentration exceeds 30% by mass, the reaction for forming the coating layer cannot be moderated even if the dropping rate is lowered, and a uniform coating layer may not be obtained.

  The dropping rate of the polyamino acid salt aqueous solution into the dispersion is preferably in the range of 1 to 1000 ml / hour, and more preferably in the range of 10 to 200 ml / hour. If the dropping rate exceeds 1 ml / hour, the reaction for forming the coating layer may be too fast to obtain a uniform coating layer. Moreover, if it is less than 1000 ml / hour, sufficient productivity may not be ensured.

Furthermore, in the present invention, it is preferable to control the reaction temperature (dispersion temperature) at the time of dropping the acidic aqueous solution or after dropping from the viewpoint of slowing the reaction for forming the coating layer. Specifically, the reaction temperature is preferably 0 to 100 ° C, more preferably 0 to 50 ° C, and further preferably 5 to 30 ° C.
When reaction temperature exceeds 100 degreeC, the reaction rate which forms a coating layer may become quick, and a uniform coating may not be performed. On the other hand, if the temperature is less than 0 ° C., the particles are likely to aggregate and a uniform coating may not be performed.

  After passing through the process of forming the coating layer as described above, the sol of the surface-coated flame retardant particles is separated by centrifuging or decanting with a poor solvent, and then dried, and then the surface-coated flame retardant Particles can be obtained.

The surface coating amount of the polyamino acid in the surface-coated flame-retardant particles obtained by the first invention is preferably in the range of 20 to 200% by mass of the entire surface-coated flame-retardant particles, and is 20 to 80% by mass. A range is more preferable. If the coating amount is less than 20% by mass, aggregates may be generated in the matrix resin, and the dispersion may become non-uniform. On the other hand, if it exceeds 200% by mass, the resin may be plasticized when dispersed in the matrix resin.
The uniformity of the coating layer can be confirmed by observing the surface-coated flame-retardant particles with a transmission electron microscope.

  According to the first method for producing surface-coated flame-retardant particles of the present invention, the volume average particle diameter (the average diameter of the circumscribed circle when the surface-coated flame-retardant particles are non-spherical) is in the range of 1 to 500 nm. A thing can be manufactured suitably. The surface-coated flame-retardant particles preferably have a volume average particle size in the range of 1 to 200 nm, more preferably in the range of 5 to 200 nm, and still more preferably in the range of 10 to 200 nm (particularly 10 to 100 nm).

  When the volume average particle diameter of the surface-coated flame retardant particles is smaller than 1 nm, the flame retardancy retention ability is lowered. When the volume average particle diameter is larger than 500 nm, the properties are equivalent to those of a commercially available volume average particle diameter of 1 μm, and flame retardancy is obtained. Therefore, it is necessary to add a large amount. The surface-coated flame retardant particles having a volume average particle diameter in the above range are uniformly dispersed in the resin. In addition, when the volume average particle diameter of the surface-coated flame-retardant particles is nanometer size, a highly transparent flame-retardant resin composition can be obtained in combination with the ability to form a fine composite.

The dispersion degree of the surface-coated flame retardant particles is preferably in the range of 0.1 to 3.0. The dispersity is more preferably in the range of 0.1 to 1.0, and particularly preferably in the range of 0.1 to 0.8.
A low degree of dispersion indicates that the particle size distribution of the surface-coated flame retardant particles is narrow, that is, the size of the particles is more uniform. When the degree of dispersion is in the above range, Flame retardancy and mechanical properties are also uniform.

(Method for producing second surface-coated flame-retardant particles)
The method for producing the second surface-coated flame-retardant particles of the present invention has a volume average particle diameter composed of a hydrate of a metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni. A coating layer is formed by allowing a vaporized product of a cyclic organosiloxane compound to act on flame-retardant particles in the range of 1 to 500 nm and ring-opening polymerization of the cyclic organosiloxane compound on the surface of the flame-retardant particles. To do.

  The method for producing the second surface-coated flame-retardant particles is a method for producing a surface-coated flame-retardant particle according to the present invention in which a coating layer containing a polysilicon is formed on the surface. By performing the surface treatment in the gas phase, a uniform coating layer can be formed without causing coating unevenness as compared with the surface treatment in the conventional liquid.

  The flame-retardant particles used in the method for producing the second surface-coated flame-retardant particles are the same as those described in the method for producing the first surface-coated flame-retardant particles.

  As the cyclic organosiloxane compound, a compound represented by the following general formula (1) is preferably used.

In said formula, n represents the integer of 3-8. The smaller the number of n, the lower the boiling point, and the greater the amount that volatilizes and adsorbs to the flame retardant particles. When n exceeds 7, it is difficult to volatilize and the coating treatment becomes insufficient, which is not preferable. In particular, the trimer is most suitable because it easily polymerizes due to its steric nature.
In the present invention, any one of the cyclic organosiloxane compounds (a) and (b) represented by the general formula (1) or a combination of two types can be used.

In the present invention, a cyclic organosiloxane compound is allowed to act on the surface of the flame retardant particles by a gas phase method.
As a specific method, for example, the flame retardant particles and the cyclic organosiloxane compound contained in separate containers may be opened in a sealed processing chamber of 100 ° C. or lower.

  When the treated flame retardant particles are taken out from the sealed treatment chamber, if the flame retardant particles are not active, the cyclic organosiloxane compound is desorbed and the surface of the flame retardant particles is returned to the original state. Although the flame retardant particles used in the present invention have active sites on the surface, the cyclic organosiloxane compound is polymerized on the particles to form a coating layer of polysilicon.

  When the surface treatment is performed by the method as described above, a special apparatus is not required, and a sealed treatment chamber that can be kept at a constant temperature is sufficient. Moreover, a desiccator can also be used when processing a small amount. However, ideally, an apparatus that can be deaerated after treatment is preferable, and a vacuum furnace or the like is most preferable.

The treatment temperature is preferably in the range of 70 to 200 ° C, more preferably in the range of 100 to 150 ° C. The treatment time is preferably in the range of 1 to 100 hours, and more preferably in the range of 6 to 48 hours. Thereafter, the cyclic organosiloxane compound that has not been polymerized can be removed by deaeration to obtain surface-coated flame-retardant particles.
The polymerization degree (number of repeating units) of the polymerized cyclic organosiloxane is preferably in the range of 10 to 1000.

The surface coating amount of the surface-coated flame-retardant particles obtained according to the second aspect of the present invention is preferably in the range of 20 to 200% by mass of the entire surface-coated flame-retardant particles, and preferably 20 to 80% by mass. A range is more preferable. If the coating amount is less than 20% by mass, aggregates may be generated in the matrix resin and dispersion may be non-uniform. Moreover, when it exceeds 200 mass%, resin may be plasticized at the time of mixing with matrix resin.
The uniformity of the coating layer can be confirmed by observing the surface-coated flame-retardant particles with a transmission electron microscope.

  According to the second method for producing surface-coated flame-retardant particles of the present invention, as in the first invention, the volume average particle diameter (if the surface-coated flame-retardant particles are non-spherical, Those having an average diameter of 1 to 500 nm can be preferably produced. The surface-coated flame-retardant particles preferably have a volume average particle size in the range of 1 to 200 nm, more preferably in the range of 5 to 200 nm, and still more preferably in the range of 10 to 200 nm (particularly 10 to 100 nm).

  The dispersion degree of the surface-coated flame retardant particles is preferably in the range of 0.1 to 3.0. The dispersity is more preferably in the range of 0.1 to 1.0, and particularly preferably in the range of 0.1 to 0.8.

<Flame-retardant resin composition and production method thereof>
Next, the flame retardant resin composition of the present invention and the production method thereof will be described. The flame-retardant resin composition of the present invention can be obtained by blending at least the surface-coated flame-retardant particles of the present invention with a matrix resin.

  By using the surface-coated flame retardant particles of the present invention, as described later, the flame retardant resin composition improves the dispersion of the flame retardant in the matrix resin and does not decrease the polymer physical properties while maintaining the flame retardant properties. Can be obtained. The above flame retardancy means that when 5 parts by mass of a flame retardant compound is contained with respect to 100 parts by mass of ethylene-vinyl acetate copolymer resin, the maximum heat generation rate specified in ISO 5660-1 is the flame retardant compound. It means that it is reduced by 25% or more compared to before inclusion.

The matrix resin of the flame retardant resin composition in which the surface-coated flame retardant particles of the present invention are dispersed is not particularly limited as long as it is a polymer compound such as rubber and plastic. Degradable resin, ABS resin, ACS resin, alkyd resin, amino resin, ASA resin, bismaleimide triazine resin, L-roll plastic resin, chlorinated polyether, chlorinated polyethylene, allyl resin, epoxy resin, ethylene-propylene copolymer , Ethylene-vinyl acetate-vinyl chloride copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer resin, FRP, ionomer, methacrylate ester-styrene copolymer, nitrile resin, polyester, olefin vinyl alcohol copolymer Polymer, petroleum resin, phenol resin, polyacetal Polyacrylate, polyallyl sulfone, polybenzimidazole, polybutadiene, polybutylene, polybutylene terephthalate, polycarbonate, polyether ether ketone, polyether ketone, polyether nitrile, polyether sulfone, polyethylene, polyethylene terephthalate, polyketone, methacrylic resin, polymethyl Pentene, polypropylene, polyphenylene ether, polyphenylene sulfide, polysulfone, polystyrene, SAN resin, butadiene-styrene resin, polyurethane, polyvinyl acetal, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, fluororesin, silicone resin, polyvinyl acetate, xylene Resin, thermoplastic elastomer, EPDM, CR, BR, nitrile rubber , Natural rubber, acrylonitrile-butadiene rubber, fluorine rubber, butyl rubber, and the like.
Of these, biodegradable resins are particularly preferred. These can be used alone or in combination of two or more.

The flame retardant resin composition of the present invention can be blended with a stabilizer that is usually blended. These are not particularly limited, for example, crosslinking agents, crosslinking accelerators, crosslinking accelerators, activators, crosslinking inhibitors, anti-aging agents, antioxidants, ozone degradation inhibitors, ultraviolet rays Absorber, light stabilizer, tackifier, plasticizer, softener, reinforcing agent, reinforcing agent, foaming agent, foaming aid, stabilizer, lubricant, mold release agent, antistatic agent, modifier, colorant, cup Ring agent, preservative, antifungal agent, modifier, adhesive, flavoring agent, polymerization catalyst, polymerization initiator, polymerization inhibitor, polymerization inhibitor, polymerization regulator, polymerization initiator, crystal nucleating agent, compatibilization Agents, dispersants, antifoaming agents and the like.
These can be used alone or in combination of two or more.

  In addition, the flame retardant resin composition of the present invention includes not only the surface-coated flame retardant particles, but also a flame retardant compound having a larger particle diameter, whereby a large gap between particles in the polymer matrix. With the effect of a stone wall where small flame retardant fine particles are buried, there is an effect of spreading the flame retardant material in the matrix resin without gaps. And flame retardance improves further by said effect.

  The flame retardant compound preferably has a volume average particle diameter in the range of 0.5 to 50 μm, and more preferably in the range of 0.5 to 30 μm. If the volume particle diameter is less than 0.5 μm, the particles may be too small to adopt a structure like the stone wall. When it is larger than 50 μm, the mechanical properties of the polymer are deteriorated.

Although it does not restrict | limit especially as said flame-retardant compound, It is preferable to use 1 or more types selected from a hydrated metal compound, an inorganic hydrate, a nitrogen-containing compound, and a silicon-containing inorganic filler.
The hydrated metal compound is preferably any one selected from aluminum hydroxide, magnesium hydroxide, and calcium hydroxide. The inorganic hydrate is preferably any one selected from calcium aluminate, dihydrated gypsum, zinc borate, barium metaborate, borax, and kaolin clay. The nitrogen-containing compound is preferably sodium nitrate. Furthermore, the silicon-containing inorganic filler is preferably any one selected from a molybdenum compound, a zirconium compound, an antimony compound, dawsonite, progopite, and smectite.

  The said flame retardant compound may be used individually by 1 type, and 2 or more types may be mixed and used for it. The flame retardant compound may be the same as or different from the compound constituting the inorganic fine particles used for the surface-coated flame retardant particles.

  The content of the flame retardant compound is preferably in the range of 0.1 to 200 parts by mass, and in the range of 0.1 to 50 parts by mass with respect to 100 parts by mass of the surface-coated flame retardant particles. Is more preferable. If the content is less than 0.1 parts by mass, the content may be too small to adopt a structure like the stone wall. If it exceeds 200 parts by mass, the amount of the flame retardant compound may be excessively increased and the mechanical properties of the polymer may be deteriorated.

  In addition to the surface-coated flame retardant particles of the present invention, small flame retardant fine particles fill the gaps between smectite particles having a large aspect ratio in the matrix resin when used in combination with organically treated smectites. Due to the effect of dots and lines, there is an effect of spreading the flame retardant material in the matrix resin without gaps.

  In addition, when the organically treated smectites are dispersed in the resin, the resin becomes transparent, and the flame retardant fine particles of the present invention have a size of visible light or less, and are added to the resin. Is uniformly dispersed, the combined compounded resin is excellent in transparency.

The flame retardant resin composition is obtained by mixing the above-described surface-coated flame retardant particles of the present invention, a matrix resin, and, if necessary, a flame retardant compound, a stabilizer and the like, and kneading them with a kneader. Obtainable.
Although it does not restrict | limit especially as said kneading machine, The method of disperse | distributing a flame-retardant fine particle by repeating a shear stress and position exchange using 3 rolls or 2 rolls, and a kneader, a Banbury mixer, an intermix, a uniaxial A method of using an extruder or a twin screw extruder and dispersing by the collision force or shearing force of the wall surface of the disperser is preferably used from the viewpoint of obtaining high dispersibility.

  The kneading temperature varies depending on the matrix resin to be used, the amount of surface-coated flame retardant particles added, etc., but is preferably in the range of 50 to 450 ° C, more preferably in the range of 60 to 380 ° C.

  On the other hand, since the surface-coated flame-retardant particles of the present invention suitably have an organic layer on the surface, not only mechanical mixing such as the kneader, twin-screw extruder and roll, but also matrix resin dissolves. Alternatively, it can be uniformly dispersed in the resin even in a swelling solution.

  It is also possible to mix the flame retardant fine particles together with the polymerization solvent in the polymerization process of resin production. Thus, having a large degree of freedom in dispersion in the resin is considered that flame retardancy appears even if the blending amount is small, and the workability is improved by not impairing the mechanical strength. Therefore, it becomes possible to apply to a processing method for obtaining a wide variety of processed products such as pellets, fibers, films, sheets, and structures.

The solvent or polymerization solvent for dissolving the matrix resin is not particularly limited, but is methanol, ethylformamide, nitromethane, ethanol, acrylic acid, acetonitrile, aniline, cyclohexanol, n-butanol, methylamine, n- Amyl alcohol, acetone, methyl ethyl ketone, chloroform, benzene, ethyl acetate, toluene, diethyl ketone, carbon tetrachloride, benzonitrile, cyclohexane, isobutyl chloride, diethylamine, methylcyclohexane, isoamyl acetate, n-octane, n-heptane, isobutyl acetate, Isopropyl acetate, methyl isopropyl ketone, butyl acetate, methyl propyl ketone, ethylbenzene, xylene, tetrahydrofuran, trichloroethylene, methyl ether Ketone, methylene chloride, pyridine, n- hexanol, isopropyl alcohol, dimethylformamide, nitromethane, ethylene glycol, glycerol formamide, di marries formamide, dimethyl sulfoxide and the like.
These can be used alone or in combination of two or more.

  The mixing temperature at that time is in the range of 0 to 200 ° C., preferably in the range of room temperature to 150 ° C., particularly preferably in the range of 10 to 100 ° C. Depending on the case, pressure may or may not be applied. May be.

  In the flame-retardant resin composition after kneading or dispersing the solution, it is preferable that the surface-coated flame-retardant particles are uniformly dispersed with a primary particle size. About this dispersion state, it can measure easily by measuring the transmittance | permeability by an ultraviolet-ray and visible light about the sheet | seat of a flame-retardant resin composition.

  The measurement method was as follows. A sample solution in which 0.5 g of flame retardant fine particles were dispersed in a solution of 10 g of ethylene-vinyl acetate copolymer (Mitsui Deyupon, EV260) dissolved in 100 ml of tetrahydrofuran was cast on a glass substrate. A film having a thickness of 20 μm is produced by drying at 3 ° C. for 3 hours, and using this as a sample, the transmittance is measured with an ultraviolet / visible light spectrophotometer.

  The transmittance determined by the above measurement method is preferably in the range of 40 to 90%, more preferably in the range of 60 to 90% in the measurement at 550 nm.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.
First, the manufacture example of the surface-coated flame-retardant particle | grains of this invention is shown. In addition, flame retardant resin compositions using these surface-coated flame retardant particles were prepared and their characteristics were also examined.

<Example 1>
(Production of surface-coated flame-retardant particles A1)
In a 2000 ml separable flask, 1000 ml of ion exchange water and 1.0 g of polyvinyl alcohol (styrene equivalent weight average molecular weight: 2000) as a dispersant were added and dissolved by heating. After cooling to room temperature, 100 g (dispersion concentration: 10% by mass) of magnesium hydroxide particles (magnesia 500H, manufactured by Ube Material Co., Ltd.) having a volume average particle size of 80 nm are added as flame retardant particles, followed by stirring and ultrasonic treatment. A dispersion was prepared.

  Next, 500 ml of a 10% by mass aqueous sodium L-glutamate solution was added dropwise at a dropping rate of 10 ml / hour while stirring and sonicating the dispersion, and stirring was continued for 60 minutes. This dispersion was heated under reduced pressure and concentrated until the liquid volume was approximately halved. At this time, the dispersion became a sol state of white magnesium hydroxide. Next, an appropriate amount of toluene was added to the obtained magnesium hydroxide sol to dissolve the sol, and aggregates were removed using a metal mesh with 10 μm pores. Next, the toluene layer was dried under reduced pressure to obtain surface-coated flame-retardant particles A1.

  The surface-coated flame-retardant particles A1 thus obtained had a volume average particle size of 80 nm and a dispersity of 0.5. Further, the surface coating amount was calculated by precisely weighing the surface coated flame retardant particles A1, and it was 25% by mass. It was confirmed that the particles were uniformly coated by observation of the particle surface with a transmission electron microscope (FEI Company Tecnai G2).

(Production of flame retardant resin composition)
The surface-coated flame-retardant particles A1 and various resins (polycarbonate resin, S-2000 manufactured by Mitsubishi Engineering Plastics; ABS resin, manufactured by Technopolymer 600) are weighed and mixed in predetermined amounts as shown in Table 1, and then 2 The strand of the flame retardant resin composition was obtained by kneading using a shaft extruder and hot-cutting the strand. The obtained chip was molded with a hot press (120 ° C. × 10 minutes) to obtain each sheet-like molded body having a thickness of 2 mm.

(Evaluation of flame retardant resin composition)
The following evaluation was performed on each sheet-like molded body produced as described above.
-Flame retardance test As a flame retardancy test, the vertical combustion test was done according to JISZ2391. The test was conducted at a sample thickness of 2 mm. About the flame retardant test pass product, the level with the highest flame retardant effect was V0, and then V1 and V2. On the other hand, those not reaching these were rejected.

・ Mechanical strength test As a mechanical strength test, an autograph (manufactured by Toyo Seiki Seisakusho Co., Ltd., V1-C) was used, and in accordance with JIS K 7161, the tensile speed was 50 mm / min at normal temperature. Strength, flexural modulus and elongation at break were measured.

-Light transmittance The total light transmittance was measured according to JIS K7105 (haze meter: manufactured by Nippon Denshoku). A sample having a size of 100 mm × 100 mm × 20 μm was used.
Further, a sample solution in which 0.5 g of the flame retardant fine particles were dispersed in a solution in which 10 g of ethylene-vinyl acetate copolymer (EV260 manufactured by Mitsui Deyupon) was dissolved in 100 ml of tetrahydrofuran was cast on a glass substrate and heated to 60 ° C. The film was dried for 3 hours to produce a film having a thickness of 20 μm, and the transmittance was measured with a haze meter.
The results are summarized in Table 1.

<Example 2>
(Production of surface-coated flame retardant particles A2)
In Example 1, polyvinyl-2-pyrrolidone (styrene-converted weight average molecular weight: 5000) was used instead of polyvinyl alcohol, and 10 g of aluminum hydroxide having a volume average particle diameter of 10 nm (dispersion concentration: 1. 0 mass%) was used in the same manner except that 500 ml of 40 mass% sodium polyaspartate was used instead of 500 ml of 10 mass% sodium L-glutamate aqueous solution, and the dropping rate of polyaspartate sodium was 100 ml / hour. Coated flame retardant particles A2 were produced.

  The surface-coated flame-retardant particles A2 thus obtained had a volume average particle size of 10 nm and a dispersity of 0.5. Further, the surface coating amount was calculated by precisely weighing the surface-coated flame-retardant particles A2, and it was 80% by mass. It was confirmed that the particles were uniformly coated by observation of the particle surface with a transmission electron microscope.

(Production and evaluation of flame retardant resin composition)
The surface-coated flame retardant particles A2 and the matrix resin were blended as shown in Table 1, and a sheet-like molded body was produced in the same manner as in Example 1, and the same evaluation was performed.
The results are summarized in Table 1.

<Example 3>
(Production of surface-coated flame-retardant particles A3)
In Example 1, 20 g of polypropylcellulose (styrene-converted volume average molecular weight: 100) instead of 1.0 g of polyvinyl alcohol, and 200 g of magnesium hydroxide particles having a volume average particle diameter of 478 nm (dispersion concentration) instead of 100 g of magnesium hydroxide : 19.6 mass%), and surface-coated flame retardant particles A3 were produced in the same manner except that the concentration of the sodium L-glutamate aqueous solution was 20 mass%.

  The obtained surface-coated flame-retardant particles A3 had a volume average particle size of 478 nm and a dispersity of 0.5. Further, the surface coating amount was calculated by precisely weighing the surface coated flame retardant particles A3, and it was 50% by mass. It was confirmed that the particles were uniformly coated by observation of the particle surface with a transmission electron microscope.

(Production and evaluation of flame retardant resin composition)
The surface-coated flame retardant particles A3 and the matrix resin were blended as shown in Table 1, and a sheet-like molded body was produced in the same manner as in Example 1, and the same evaluation was performed.
The results are summarized in Table 1.

<Examples 4 to 6>
Using the surface-coated flame retardant particles A1 to A3, sheet moldings were prepared as shown in Table 1 and evaluated in the same manner as in Example 1.
The results are summarized in Table 1.

<Comparative Example 1>
In the production of the flame retardant resin composition in Example 1, a sheet-like molded body was produced in the same manner except that the flame retardant particles were not blended, and the same evaluation was performed.
The results are summarized in Table 2.

<Comparative Example 2>
(Manufacture of surface-coated flame-retardant particles B1)
In Example 1, 10 g of magnesium hydroxide having a volume average particle size of 2000 nm (dispersion concentration: 1% by mass) was used instead of 100 g of magnesium hydroxide having a volume average particle size of 80 nm, and the concentration of the L-sodium glutamate aqueous solution was 40% by mass. The surface-coated flame-retardant particles B1 were produced in the same manner except that the content was%.

  The obtained surface-coated flame-retardant particles B1 had a volume average particle diameter of 2000 nm and a dispersity of 6.0. Further, the surface coating amount was calculated by precisely weighing the surface-coated flame-retardant particles B1, and it was 5% by mass. As a result of observation with a transmission electron microscope, several particles were aggregated, and one particle Also, the occurrence of an uncoated portion on the surface was confirmed.

(Production and evaluation of flame retardant resin composition)
The surface-coated flame retardant particles B1 and the matrix resin were blended as shown in Table 1, and a sheet-like molded body was produced in the same manner as in Example 1, and the same evaluation was performed.
The results are summarized in Table 2.

<Comparative Example 3>
Using the surface-coated flame retardant particles B1, sheet molded bodies were prepared as shown in Table 2 and evaluated in the same manner as in Example 1.
The results are summarized in Table 2.

<Comparative example 4>
In the production of the flame retardant resin composition in Example 1, magnesium hydroxide fine particles having an untreated volume average particle size of 80 nm (Magnesia, manufactured by Ube Material Co., Ltd.) are used as the flame retardant particles C1 instead of the flame retardant particles A1. 500H), a polycarbonate resin was used as the matrix resin, and a sheet-like molded body was prepared in the same manner except that the composition shown in Table 2 was used, and the same evaluation was performed.
The results are summarized in Table 2.

<Comparative Example 5>
In preparation of the flame retardant resin composition in Example 1, flame retardant particles C1 were used in place of the flame retardant particles A1, ABS resin was used as the matrix resin, and the formulation shown in Table 2 was used. Similarly, a molded sheet was produced and evaluated in the same manner.
The results are summarized in Table 2.

<Example 7>
(Preparation of surface-coated flame-retardant particles D1)
200 g of magnesium hydroxide particles (magnesia 50H, manufactured by Ube Material Co., Ltd.) having a volume average particle size of 80 nm as flame retardant particles and 200 g of octamethylcyclotetrasiloxane as cyclic organosiloxane compounds were weighed in separate glass containers. . Each of these containers was placed in a desiccator that can be depressurized and sealed. Next, the internal pressure of the desiccator was reduced to 80 mmHg with a vacuum pump and then sealed. Thereafter, the desiccator container was left to stand for 12 hours in an environment of 60 ° C. for treatment. After the treatment, the surface-coated flame retardant particles D1 subjected to the surface treatment were taken out from the glass container.

  The obtained surface-coated flame retardant particles D1 had a volume average particle size of 80 nm and a dispersity of 0.5. Moreover, when the surface coating flame-retardant particle | grains D1 were precisely weighed and the surface coating amount was computed, it was 50 mass%, and it was confirmed also by observation with a transmission electron microscope.

(Production and evaluation of flame retardant resin composition)
Moreover, using the surface-coated flame retardant particles D1, sheet molded articles were prepared as shown in Table 4 and evaluated in the same manner as in Example 1.
The results are summarized in Table 4.

<Examples 8 to 13>
(Preparation of surface-coated flame retardant particles D2 to D7)
In the production of the surface-coated flame-retardant particles of Example 7, the same manner as in Example 7 except that the type and amount of flame-retardant particles, the treatment pressure, the treatment temperature, and the treatment time were changed as shown in Table 3 below. Thus, surface-coated flame retardant particles D2 to D7 were produced. These conditions and the coating amount are also shown in Table 3.

(Production and evaluation of flame retardant resin composition)
In addition, using these surface-coated flame-retardant particles D2 to D7, sheet molded articles were prepared as shown in Table 4 and evaluated in the same manner as in Example 1.
The results are summarized in Table 4.

<Example 14>
Surface-coated flame-retardant particles D1 and a matrix resin were blended as shown in Table 4, and a sheet-like molded body was produced in the same manner as in Example 1, and the same evaluation was performed.
The results are summarized in Table 4.

<Comparative Example 6>
(Preparation of surface-coated flame-retardant particles E1)
In the preparation of the surface-coated flame-retardant particles of Example 7, the surface-coated flame was difficult except that magnesium hydroxide particles having a volume average particle diameter of 2000 nm were used instead of magnesium hydroxide particles having a volume average particle diameter of 80 nm. Flammable particles E1 were produced.

  The obtained surface-coated flame-retardant particles E1 had a volume average particle diameter of 2000 nm and a dispersity of 6.0. Further, when the surface coating amount was calculated by precisely weighing the surface-coated flame-retardant particles E1, it was 10% by mass, and the occurrence of an uncoated portion was also confirmed by observation with a transmission electron microscope.

(Production and evaluation of flame retardant resin composition)
The surface-coated flame retardant particles E1 and the polycarbonate resin were blended as shown in Table 4 to prepare a sheet-like molded body in the same manner as in Example 1, and the same evaluation was performed.
The results are summarized in Table 4.
A sheet-like molded body was produced in the same manner as in Example 1, and the same evaluation was performed.
The results are summarized in Table 4.

<Comparative Example 7>
Surface-coated flame retardant particles E1 and the ABS resin were blended as shown in Table 4 to prepare a sheet-like molded body in the same manner as in Example 1, and the same evaluation was performed.
The results are summarized in Table 4.

  From the above results, the flame-retardant resin composition containing the surface-coated flame-retardant particles of the present invention has high flame retardancy and has a transparent overview without impairing mechanical properties. I understand. It was also found that even when used in combination with ordinary flame retardants (flame retardant compounds), it has high flame retardancy and does not impair mechanical properties.

Claims (6)

  On the surface of the flame retardant particles comprising a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni and having a volume average particle diameter in the range of 1 to 500 nm. A surface-coated flame-retardant particle, wherein a coating layer containing a polyamino acid or a polysilicone is formed.   A flame-retardant particle comprising a hydrate of at least one metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni and having a volume average particle diameter of 1 to 500 nm. A flame-retardant resin composition comprising surface-coated flame-retardant particles having a coating layer containing a polyamino acid or poly-silicone formed on a surface thereof, and a matrix resin.   At least an aqueous solution in which a dispersant is dissolved is composed of a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni, and a volume average particle diameter is 1 to 500 nm. A step of preparing a dispersion by dispersing the flame retardant particles in the range, and dropping a polyamino acid salt aqueous solution into the dispersion to deposit a polyamino acid on the surface of the flame retardant particles to form a coating layer A process for producing surface-coated flame-retardant particles.   It consists of a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni, and is formed into a flame retardant particle having a volume average particle diameter in the range of 1 to 500 nm. A method for producing surface-coated flame-retardant particles, wherein a vaporized product of an organosiloxane compound is allowed to act to cause ring-opening polymerization of a cyclic organosiloxane compound on the surface of the flame-retardant particles.   A surface-coated flame-retardant particle produced by the method for producing a surface-coated flame-retardant particle according to claim 3 or 4. Mixing at least the matrix resin and the surface-coated flame-retardant particles, and kneading with one or more kneaders selected from a roll, a kneader, a Banbury mixer, an intermix, a single screw extruder, and a twin screw extruder. A method for producing a flame-retardant resin composition, comprising:
The surface-coated flame-retardant particles are made of a hydrate of one kind of metal selected from Mg, Ca, Al, Fe, Zn, Ba, Cu and Ni, and have a volume average particle diameter of 1 to 500 nm. A method for producing a flame-retardant resin composition, which is surface-coated flame-retardant particles in which a coating layer containing a polyamino acid or poly-silicone is formed on the surface of the flame-retardant particles.