JP2008231241A - Hollow resin particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow resin particle having low specific gravity and high heat-resistance and containing a resin free from a nitrile group as the shell-constituting resin. <P>SOLUTION: The hollow resin particle has absolute specific gravity of 0.005-0.1 and a volume-average particle diameter of 1-250 μm and contains a vinyl resin (A) derived from a vinyl monomer (a) free from a nitrile group as the shell-constituting resin. The vinyl resin (A) is preferably a resin having a crosslinked structure. The vinyl monomer (a) preferably contains ≤30 mol% monomer having a carboxy group and is at least one kind of monomer selected from a monomer having a hydroxy group, a monomer having an amino group and a monomer having a carboxylic acid ester bond. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a hollow resin particle whose shell is composed of a vinyl resin made of a monomer having no nitrile group.

Since the hollow resin particles have a very low specific gravity and a small particle size, they have been used in various resin materials, paints, building materials and the like for the purpose of reducing weight and improving heat insulation. Conventional hollow resin particles are produced by synthesizing thermally expandable microcapsules encapsulating a low-boiling solvent and performing a heat treatment. In order to adopt a mechanism in which the low-boiling solvent encapsulated during the heat treatment has an internal pressure and pushes the shell plasticized by heat, it is necessary to use a resin having a gas barrier property such as a nitrile resin. (For example, see Patent Document 1)
Since the conventional hollow resin particles use the above production process, most of them use a nitrile monomer, and the nitrile group is eliminated at around 200 ° C., and the strength of the shell is remarkably lowered. Although there are some reports on other vinyl resins, the true specific gravity is 0.6 or more, the internal space ratio is low, and the practicality is low. (For example, refer to Patent Document 2) Although polystyrene hollow particles are also disclosed, there is a problem that the particle diameter is as large as several millimeters but the application is limited although the specific gravity is low. (For example, see Patent Document 3)
JP 62-286534 A JP 7-41594 A JP-A-6-073225

  An object of the present invention is to provide hollow resin particles having a shell resin having no nitrile group, a low specific gravity, and heat resistance.

As a result of intensive studies, the present inventors have completed the present invention.
That is, the present invention is a vinyl resin (A) comprising a vinyl monomer (a) whose shell constituent resin does not have a nitrile group, has a true specific gravity of 0.005 to 0.1, and has a volume average particle size. A hollow resin particle having a diameter of 1 to 250 μm and a method for producing the same.

  In the hollow resin particles of the present invention, since the constituent resin of the shell is made of a vinyl monomer (a) having no nitrile group, the strength of the shell is reduced because the nitrile group is not detached even at a high temperature, for example, around 200 ° C. Hard to do. Moreover, since the true specific gravity is 0.005 to 0.1 and the specific gravity is low, the weight can be reduced. Moreover, since a volume average particle diameter is 1-250 micrometers and a particle size is small, it can be used for a wide use, for example, can be added also to a thin film.

The resin constituting the shell of the hollow resin particles of the present invention is a vinyl resin (A) made of a vinyl monomer (a) having no nitrile group. The number average molecular weight of the vinyl resin (A) is preferably 5,000 to 1,000,000 when it is not a crosslinked resin. The vinyl resin (A) is a homopolymer or copolymer of the following vinyl monomer (a) having no nitrile group. The resin constituting the shell may be a mixture of vinyl resin (A) and non-vinyl resin.
Examples of the non-vinyl resin include polyurethane resin, polyester resin, polycarbonate resin, epoxy resin, polyamide resin, and polyimide resin from the viewpoint of affinity with the vinyl resin (A). Among these, polyurethane resins, polycarbonate resins, and polyamide resins are preferable. The content of the non-vinyl resin is preferably 10 to 50% by weight with respect to the weight of the mixture of the vinyl resin (A) and the non-vinyl resin.

As a specific example of the vinyl monomer (a) having no nitrile group,
(A1) Vinyl hydrocarbon (a11) Aliphatic vinyl hydrocarbon: ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, other α-olefins, etc. (a12) Alicyclic ring Formula vinyl hydrocarbon: cyclohexene, pinene, etc. (a13) Aromatic vinyl hydrocarbon: styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexyl Styrene, benzyl styrene, crotylbenzene, vinyl naphthalene, etc.

(A2) Carboxyl group-containing vinyl monomers and salts thereof (Meth) acrylic acid, (anhydrous) maleic acid, maleic acid monoalkyl ester, fumaric acid, fumaric acid monoalkyl ester, crotonic acid, itaconic acid, itaconic acid monoalkyl ester Carboxyl group-containing vinyl monomers such as itaconic acid glycol monoether, citraconic acid, citraconic acid monoalkyl ester and cinnamic acid; and alkali metal salts thereof (sodium salts, potassium salts, etc.), alkaline earth metal salts (calcium Salt, magnesium salt, etc.), amine salt or ammonium salt.

(A3) Sulfone group-containing vinyl monomer, vinyl sulfate monoesterified product and salts thereof Vinyl sulfonic acid (salt), (meth) allyl sulfonic acid (salt), methyl vinyl sulfonate, styrene sulfonic acid (salt), α-methylstyrenesulfonic acid (salt), sulfopropyl (meth) acrylate, 2-hydroxy-3- (meth) acryloxypropylsulfonic acid (salt), 2- (meth) acryloylamino-2,2-dimethylethanesulfone Acid (salt), 2- (meth) acryloyloxyethanesulfonic acid (salt), 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid (salt), 2- (meth) acrylamido-2-methylpropanesulfonic acid (Salt), 3- (meth) acrylamide-2-hydroxypropanesulfonic acid (salt), alkyl (C3-C18) allylsulfosuccinic acid (salt), poly (n = 2-30) oxyalkylene (ethylene, propylene, butylene: single, random or block) mono (meth) acrylate sulfate ester (salt ) [Poly (n = 5 to 15) oxypropylene monomethacrylate sulfate ester (salt), etc.], polyoxyethylene polycyclic phenyl ether sulfate (salt). [Examples of the salt include alkali metal salts (sodium salt, potassium salt, etc.), alkaline earth metal salts (calcium salt, magnesium salt, etc.), amine salts, and ammonium salts. ]

(A4) Phosphoric acid group-containing vinyl monomer (meth) acrylic acid hydroxyalkyl phosphoric acid monoester, for example, 2-hydroxyethyl (meth) acryloyl phosphate, phenyl-2-acryloyloxyethyl phosphate, (meth) acrylic acid alkylphosphonic acids For example, 2-acryloyloxyethylphosphonic acid (salt).

(A5) Hydroxyl group-containing vinyl-based monomer Hydroxystyrene, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, (meth) allyl alcohol, crotyl Alcohol, isocrotyl alcohol, 1-buten-3-ol, 2-buten-1-ol, 2-butene-1,4-diol, propargyl alcohol, 2-hydroxyethylpropenyl ether, sucrose allyl ether, and the like.

(A6) Nitrogen-containing vinyl monomer (a61) Amino group-containing vinyl monomer: aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl methacrylate, N-amino Ethyl (meth) acrylamide, (meth) allylamine, morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, crotylamine, N, N-dimethylaminostyrene, methyl α-acetaminoacrylate, vinylimidazole, N-vinylpyrrole, N -Vinylthiopyrrolidone, N-arylphenylenediamine, aminocarbazole, aminothiazole, aminoindole, aminopyrrole, aminoimidazole, aminomercaptothiazole (A62) Amide group-containing vinyl monomers: (meth) acrylamide, N-methyl (meth) acrylamide, N-butylacrylamide, diacetone acrylamide, N-methylol (meth) acrylamide, cinnamic acid amide, N, N-dimethylacrylamide, N, N-dibenzylacrylamide, methacrylformamide, N-methyl N-vinylacetamide, N-vinylpyrrolidone, etc. (a63) Quaternary ammonium cation group-containing vinyl monomers: dimethylaminoethyl (meth) acrylate, Quaternized products of tertiary amine group-containing vinyl monomers such as diethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, diallylamine and the like (methylchlora Quaternized with quaternizing agents such as id, dimethyl sulfate, benzyl chloride, dimethyl carbonate)
(A64) Nitro group-containing vinyl monomers: nitrostyrene and the like.

(A7) Epoxy group-containing vinyl monomer Glucidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, p-vinylphenylphenyl oxide and the like.

(A8) Halogen element-containing vinyl monomers Vinyl chloride, vinyl bromide, vinylidene chloride, allyl chloride, chlorostyrene, bromostyrene, dichlorostyrene, chloromethylstyrene, tetrafluorostyrene, chloroprene, and the like.

(A9) Vinyl esters, vinyl ethers, vinyl ketones Vinyl acetate, vinyl butyrate, vinyl propionate, vinyl butyrate, isopropenyl acetate, methyl 4-vinylbenzoate, cyclohexyl methacrylate, benzyl methacrylate, phenyl (meth) acrylate, vinyl methoxyacetate, Vinyl benzoate, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether, vinyl 2-ethylhexyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether, vinyl 2-butoxyethyl ether, 3,4-dihydro 1,2 -Pyran, 2-butoxy-2'-vinyloxydiethyl ether, vinyl 2-ethylmercaptoethyl ether, vinyl methyl ketone, vinyl Tilketone, vinylphenylketone, p-vinyldiphenylsulfide, vinylethylsulfide, vinylethylsulfone, dialkyl fumarate (two alkyl groups are linear, branched or alicyclic groups having 2 to 8 carbon atoms) Dialkyl maleate (two alkyl groups are linear, branched or alicyclic groups having 2 to 8 carbon atoms) and the like.

(A10) Alkyl (meth) acrylate Alkyl (meth) acrylate having an alkyl group having 1 to 50 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like.

(A11) Vinyl monomer having a polyalkylene glycol chain Polyethylene glycol (molecular weight 300) mono (meth) acrylate, polypropylene glycol (molecular weight 500) monoacrylate, methyl alcohol ethylene oxide 10 mol adduct (meth) acrylate, lauryl alcohol ethylene oxide 30 mole adduct (meth) acrylate and the like.

(A12) Other vinyl monomers Acetoxystyrene, phenoxystyrene, ethyl α-ethoxy acrylate, isocyanatoethyl (meth) acrylate, m-isopropenyl-α, α-dimethylmethylbenzyl isocyanate and the like.

Of these, (a5) hydroxyl group-containing vinyl monomers and (a61) amino group-containing vinyl monomers are preferred from the viewpoint of ease of surface modification and ease of compatibility with resins, and high total light transmittance. In view of the above, monomers having a carboxylic acid ester bond [for example, (a10) alkyl (meth) acrylate, (a9) vinyl ester, etc.] are preferable.
Moreover, when using the monomer which has a carboxyl group for vinyl resin (A), from a viewpoint of the softness | flexibility of vinyl resin (A) and the specific gravity of a hollow particle, 30 mol% or less is preferable, More preferably 25 mol% or less.

The true specific gravity of the hollow resin particles of the present invention is 0.005 to 0.1, preferably 0.01 to 0.09, and more preferably 0.02 to 0.08. When the true specific gravity is less than 0.005, the strength of the shell is insufficient, and when it exceeds 0.1, the industrial utility value is low.
The true specific gravity can be measured by a general liquid method.

The volume average particle diameter of the hollow resin particles of the present invention is 1 to 250 μm, preferably 5 to 200 μm, more preferably 10 to 150. When the volume average particle diameter is less than 1 μm, it is difficult to reduce the specific gravity, and when it exceeds 250 μm, it is difficult to maintain the hollow shape.
The measuring method of a volume average particle diameter can be measured based on JISZ8825-1: 2001.

  The 10 wt% heat loss temperature of the hollow resin particles of the present invention is preferably 200 to 400 ° C, more preferably 270 to 350 ° C. The hollow resin particles of the present invention having such a 10% by weight heat loss temperature are preferred from the viewpoint of the heat resistance of the hollow particles. The 10 wt% heat loss temperature can be measured with a TG-DTA (thermogravimetric method-differential thermal analysis method) calorimeter. Examples of the resin constituting the shell of the hollow resin particles include a crosslinked (meth) acrylate, a copolymer of (meth) acrylate and a carboxylic acid group-containing monomer. Specific examples include cross-linked polymethyl methacrylate, polymethyl methacrylate-methacrylic acid copolymer, and the like.

The vinyl resin (A) constituting the shell of the hollow resin particles of the present invention is preferably a resin having a crosslinked structure from the viewpoint of heat resistance.
As vinyl-type resin (A) which has a crosslinked structure, what contains 0.1-80 mol% of a crosslinking agent monomer is preferable, More preferably, it contains 0.5-75 mol%. As the crosslinking agent monomer, it is preferable to use a monomer having two or more vinyl groups in one molecule. Specific examples include ethylene glycol dimethacrylate and divinylbenzene.

When the hollow resin particles of the present invention are used for optical applications, the total light transmittance of the vinyl resin (A) is preferably 80% or more, more preferably 85% or more, from the viewpoint of light scattering properties. Preferably it is 90% or more. The total light transmittance can be measured by preparing a 200 μm film of a resin having the same composition as the vinyl resin (A) of the hollow resin particles of the present invention and using a general transmitted light measuring device.

From the viewpoint of light absorption at a specific wavelength, the vinyl resin (A) is preferably composed of a monomer (a) having no aromatic ring.

The hollow resin particles of the present invention are produced, for example, by the following method.
Vinyl resin (A) vinyl monomer (a) having no nitrile group and phase separation accelerator (C) in solution (E) dissolved in volatile solvent (B) are converted to vinyl having no nitrile group. A liquid suspended in the solvent (D) which is insoluble in the monomer (a), the vinyl resin (A) and the volatile solvent (B) and has a boiling point higher than that of the volatile solvent (B) is polymerized under pressure. Then, after synthesizing the vinyl resin (A), it can be produced by depressurization at a temperature equal to or higher than the boiling point of the volatile solvent (B).

The phase separation accelerator (C) is a phosphate ester represented by any one of the general formulas (1) to (3), or a mixture thereof.
R ₁ is an alkyl group having 2 to 30 carbon atoms, preferably 8 to 18 carbon atoms, and an aromatic group having 6 to 100 carbon atoms, preferably 15 to 80 carbon atoms, and an aliphatic aromatic group having 7 to 100 carbon atoms, preferably 15 to 80 carbon atoms. Group. More preferably, it is a 12-16 alkyl group.
R ₁ is the same as in general formula (1). R ₂ is the same as R ₁ .
R ₁ and R ₂ are the same as those in the general formula (2). R ₃ is the same as R ₁ .
Specific examples of the phase separation accelerator (C) include monolauryl phosphate, dilauryl phosphate, trilauryl phosphate and the like.

The volatile solvent (B) is preferably a volatile solvent in which the difference between the solubility parameter of the vinyl resin (A) and the solubility parameter of the volatile solvent (B) is 2 to 10.
The solubility parameter (hereinafter referred to as SP value) is a value calculated by the Fedors method described in “Polymer Engineering and Science, Vol. 14, No. 2, p 147 to 154 (1974)”.

Specific examples include the following organic solvents having a molecular weight of 100 or less.
Examples of the volatile solvent (B) include aromatic hydrocarbon solvents such as toluene and benzene; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; alicyclic hydrocarbon solvents such as cyclohexane; methyl chloride Halogen solvents such as methyl bromide and methylene dichloride; ester solvents such as ethyl acetate; ether solvents such as diethyl ether, tetrahydrofuran, dioxane and ethyl cellosolve; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone Alcoholic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and t-butanol; amides such as dimethylformamide (hereinafter referred to as DMF) and dimethylacetamide Solvent; sulfoxide solvents such as dimethyl sulfoxide, N- heterocyclic compound-based solvents such as methylpyrrolidone, and a mixed solvent of two or more thereof.

Of these, preferred are aliphatic hydrocarbon solvents such as pentane, hexane and heptane; and alicyclic hydrocarbon solvents such as cyclohexane.
When the solvent (D) is water, the boiling point of the volatile solvent (B) is preferably 99 ° C. or lower, more preferably 85 ° C. or lower, 80 ° C. or lower, and 35 ° C. or higher.

In the solution (E) in which the vinyl monomer (a) having no nitrile group and the phase separation accelerator (C) are dissolved in the volatile solvent (B), the weight% of the monomer (a) is the weight of the solution (E). The content is preferably 10 to 90% by weight, more preferably 20 to 80% by weight.
The weight% of the phase separation accelerator (C) is preferably 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, based on the weight of the solution (E).

The method for preparing the solution (E) is not particularly limited, and the monomer (a), the phase separation accelerator (C), and the volatile solvent (B) are mixed and dissolved by a usual method.

The solvent (D) is insoluble in the monomer (a), the vinyl resin (A), and the volatile solvent (B).
(D) (a) which melt | dissolves with respect to 100 weight part is 10 weight part or less.
The solvent (D) does not dissolve or swell the vinyl resin (A).
The solvent (D) is not mutually soluble with the volatile solvent (B).
The solvent (D) is a solvent having a boiling point higher than that of the volatile solvent (B).
Specific examples of the solvent (D) include water, toluene and the like depending on the types of (a), the vinyl resin (A) and the volatile solvent (B).
Specifically, as a combination of (D), (a) and (B), for example, (1) a combination of water, hexane and a hydrophobic precursor, (2) a combination of toluene, acetone or DMF and a hydrophilic precursor Etc.

The method of suspending the solution (E) in the solvent (D) includes (1) a mixture of the solution (E) and the solvent (D) at a temperature below the boiling point of the volatile solvent (B) and the monomer (a). A method of stirring and suspending in the usual manner, or a method of suspending using the following dispersing device, (2) Suspending the solution (E) in the solvent (D) in the same manner as in (1) (3) A method of suspending in the same manner as in (1) while dropping the solvent (D) in the solution (E).

  The dispersing apparatus is not particularly limited as long as it is generally marketed as an emulsifier or a dispersing machine. For example, a homogenizer (manufactured by IKA), polytron (manufactured by Kinematica), TK auto homomixer (specialized machine) Kogyo Kogyo Co., Ltd.), batch type emulsifiers such as Kogyo Kogyo Kogyo Kogyo Co., Ltd. , Continuous emulsifiers such as Trigonal wet pulverizer (Mitsui Miike Chemical Co., Ltd.), Captron (Eurotech Co., Ltd.), Fine Flow Mill (Pacific Kiko Co., Ltd.), Microfluidizer (Mizuho Industrial Co., Ltd.), Nanomizer (Nanomizer Co., Ltd.), APV Gaurin (Gaulin Co., Ltd.) and other high-pressure emulsifiers, Membrane emulsifier (Chilling Industries Co., Ltd.) membrane milk Machine, Vibro Mixer (Hiyaka Kogyo) vibrating emulsifier such as, ultrasonic emulsifier such as an ultrasonic homogenizer (manufactured by Branson Co., Ltd.). Among these, APV Gaurin, homogenizer, TK auto homomixer, Ebara milder, TK fill mix, and TK pipeline homomixer are preferable from the viewpoint of uniform particle size.

The liquid in which the solution (E) is suspended in the solvent (D) is preferably polymerized under the following conditions.
Temperature: A normal temperature at which the polymerization of each monomer (a) is performed.
Pressure (expressed in absolute pressure): preferably 0.1 to 2 MPa, more preferably 0.15 to 1 MPa. The gas used for pressurization is preferably nitrogen or a rare gas (such as helium, neon, or argon).
Time: Usually 3 to 20 hours.

The polymerization initiator used in the polymerization of the vinyl resin is one that dissolves in the solution (E) and includes a peroxide polymerization initiator (a) and an azo polymerization initiator (b). . Further, the redox polymerization initiator (c) may be formed by using a peroxide polymerization initiator (a) and a reducing agent in combination. Furthermore, you may use 2 or more types together from (a)-(c).

(A) Peroxide-based polymerization initiator (a1) Oil-soluble peroxide-based polymerization initiator: acetylcyclohexylsulfonyl peroxide, isobutyryl peroxide, diisopropyl peroxydicarbonate, etc. (a2) Water-soluble peroxide-based polymerization initiator: Hydrogen peroxide, peracetic acid, ammonium persulfate, sodium persulfate, etc.

(B) Azo polymerization initiator:
(B1) Oil-soluble azo polymerization initiator: 2,2′-azobisisobutyronitrile, 1,1′-azobiscyclohexane 1-carbonitrile, 2,2′-azobis-4-methoxy-2,4 -Dimethylvaleronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, dimethyl-2,2'-azobis (2-methylpropionate), 1,1'-azobis (1-acetoxy-1- Phenylethane), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) and the like.
(B2) Water-soluble azo polymerization initiator: azobisamidinopropane salt, azobiscyanovaleric acid (salt), 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], etc. .

(C) Redox polymerization initiator (c1) Non-aqueous redox polymerization initiator Oil-soluble peroxide such as hydroperoxide, dialkyl peroxide, diacyl peroxide, tertiary amine, naphthenate, mercaptans, organometallic Used in combination with oil-soluble reducing agents such as compounds (triethylaluminum, triethylboron, diethylzinc, etc.).
(C2) Water-based redox polymerization initiator Water-soluble peroxides such as persulfates, hydrogen peroxide, hydroperoxides, and water-soluble inorganic or organic reducing agents (divalent iron salts, sodium hydrogen sulfite, alcohols, polyamines, etc. ) In combination.

When the solution (E) is suspended in the solvent (D), it is preferably carried out in the presence of the surfactant (F).

As the surfactant (F), a commonly used surfactant can be used, and an anionic surfactant (F-1), a cationic surfactant (F-1), an amphoteric surfactant (F-3), Nonionic surfactant (F-4), reactive surfactant (F-5), etc. are mentioned. The surfactant (F) may be a combination of two or more surfactants.
Among these, an anionic surfactant (F-1) is preferable, and specific examples include alkylbenzene sulfonates, particularly sodium dodecylbenzenesulfonate.
The amount of (F) added is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, based on the weight of the solvent (D).
Surfactant (F) may be added in advance in solvent (D) or solution (E), or may be added when solution (E) is suspended in solvent (D). It is preferable to add in advance to the solvent (D).

By synthesizing the vinyl resin (A) by polymerization under pressure, a liquid in which the resin particles made of the vinyl resin (A) are suspended in the solvent (D) is obtained. The suspension is then depressurized above the boiling point of the volatile solvent (B). That is, the pressure inside the reaction vessel is pressurized during polymerization and the vapor pressure (B) generated by setting the boiling point to be equal to or higher than the boiling point of (B). This pressure is released to atmospheric pressure. By this operation, hollow resin particles having the vinyl resin (A) as a shell are obtained.

The mechanism for producing hollow resin particles in the present invention is presumed as follows.
That is, the solution (E) is dispersed in the solution (D), and the monomer (a) in the solution (E) is reacted under pressure to synthesize a vinyl resin (A). Since the vinyl resin (A) is insoluble in the volatile solvent (B), the vinyl resin (A) precipitates in the particles and moves in the direction of the solvent (D), and the resin (A) and the volatile solvent ( By orienting the phase separation accelerator (C) at the interface of B), phase separation is promoted to form microcapsules. By removing the pressure at a temperature equal to or higher than the boiling point of the volatile solvent (B) under pressure, the vinyl resin (A) is expanded by the internal pressure of the encapsulated volatile solvent (B), and hollow resin particles are formed. The

Since the obtained hollow resin particles are usually obtained in a suspended state in the reaction liquid, the hollow resin particles can be obtained by removing the lower layer liquid after washing with a solvent if necessary.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this.
Hereinafter, a part shows a weight part.

<Production Example 1>
A glass reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen introduction tube was charged with 73 parts of lauryl alcohol and 48 parts of anhydrous phosphoric acid, and reacted at 65 ° C. for 8 hours to obtain an esterified product. Subsequently, 6 parts of water was added and reacted at 65 ° C. for 2 hours to obtain a phase separation accelerator (C-1).

<Production Example 2>
In the same manner as in Production Example 2, 146 parts of lauryl alcohol and 48 parts of phosphoric anhydride were charged and reacted at 65 ° C. for 8 hours to obtain an esterified product. Next, 6 parts of water was added and reacted at 65 ° C. for 2 hours to obtain a phase separation accelerator (C-2).

<Production Example 3>
In the same manner as in Production Example 3, 219 parts of lauryl alcohol and 48 parts of phosphoric anhydride were charged and reacted at 65 ° C. for 8 hours to obtain an esterified product. Next, 6 parts of water was added and reacted at 65 ° C. for 2 hours to obtain a phase separation accelerator (C-3).

<Examples 1-7>
According to the blending ratio (weight ratio) shown in Table 1, the vinyl monomer (a) having no nitrile group as the dispersed phase (solution (E)), phase separation accelerator (C), volatile solvent (B), polymerization initiation The agent or the reaction catalyst was mixed uniformly. Moreover, surfactant (F) was added according to the solvent (D) and Table 1 as a continuous phase, and it mixed uniformly. After adding the dispersed phase to the obtained continuous phase, the obtained mixed solution was stirred at 10,000 rpm for 2 minutes using a TK homomixer [manufactured by Tokushu Kika Kogyo Co., Ltd.]. The obtained aqueous dispersion was transferred to a pressure resistant reactor and reacted at the polymerization temperature shown in Table 1 for 8 hours. Then, the aqueous dispersion (GL-1 to GL-7) was obtained by adjusting to the pressure removal pressure shown in Table 1 and releasing the pressure. The obtained aqueous dispersion was filtered and dried to obtain hollow resin particles (G-1 to G-7) of the present invention. Table 1 shows the solubility parameters of the vinyl-based resin (A) and the volatile solvent (B), and their differences.

<Comparative Example 1>
It is obtained by uniformly mixing 25 parts of divinylbenzene, 0.5 part of benzoyl peroxide, and 25 parts of hexadecane with 1500 parts of an aqueous solution obtained by dissolving 5 parts of polyvinyl alcohol (polymerization degree 1700, saponification degree 88%) in water. The solution was suspended. The suspension was carried out using a homogenizer as an apparatus and stirring conditions of 1000 rpm and room temperature. Subsequently, the suspension was heated at 70 ° C. with stirring under a nitrogen gas atmosphere, and suspension polymerization was performed for 24 hours. The dispersion obtained above is filtered using a filter paper, and the hollow polymer fine particles are isolated and dried under the conditions of a temperature of about 70 ° C. and a pressure of about 0.1 MPa (under atmospheric pressure). Hexadecane evaporated to obtain hollow resin fine particles (H-1) enclosing air therein.

<Comparative example 2>
100 parts of pentane (solvent: boiling point 36 ° C.), 100 parts of acrylonitrile, 80 parts of methacrylonitrile, 15 parts of methyl methacrylate and 20 parts of azobisbutyronitrile are added and dissolved to form an oil phase. 10 parts of emulsifier (Caribbon B (Sanyo Chemicals)) is dissolved in 800 parts of ion-exchanged water, and this is used as an aqueous phase. The aqueous phase and the oil phase are mixed and dispersed under the condition of 4000 rpm × 1 minute using a homomixer. The volume average particle diameter of the oil droplets was 20 μm. This dispersion is reacted at 60 ° C. for 10 hours. After completion of the reaction, the obtained spherical resin was taken out of the water by filter paper filtration and dried with a circulating dryer at 40 ° C. The spherical body was pulverized with a sonic classifier and sieved to obtain 280 parts of thermally expandable microcapsules (volume average particle diameter 24.7 μm). The value obtained by subtracting the SP value of the solvent pentane from the SP value of the obtained polymer was 2.1.
100 g of the heat-expandable microcapsules obtained above are spread on a release paper to an area of about 100 cm ³ 1 and heat-treated for 3 minutes in a circulating dryer at 180 ° C., so that the hollow resin fine particles (H-2) are obtained. Obtained.

  The hollow resin particles (G-1 to G-7, H-1 and 2) were evaluated for performance according to the evaluation methods (1), (2) and (3) described later. The results and yield are shown in Table 2.

[Evaluation methods]
(1) In accordance with JIS Z8825-1: 2001, 0.1 g of a measurement sample is dispersed in 100 ml of methyl alcohol, and a laser scattering particle size distribution measuring apparatus LA-920 (25 ° C., manufactured by Horiba, Ltd.) is used. Used to measure the volume average particle size (DV _{G in the} table).

(2) True specific gravity (evaluation of hollow resin particles (G))
Accurately measure 0.1 g of the hollow resin particles (G) in a 10 ml graduated cylinder, and put ion exchange water in the container so that the total amount becomes 10 ml. At that time, the weight of the ion-exchange water added is measured, and the true specific gravity is calculated by the following formula.

(3) Evaluation of hollow shape by TEM (transmission electron microscope) (Evaluation of hollow resin particles (G))
After the hollow resin particles (G) are dispersed in a commercially available epoxy resin and cured by heating, the cross section of the resin cut with a diamond cutter is observed with a TEM (transmission electron microscope). I confirmed that there was.
○ indicates a hollow shape.
X shows that it is not a hollow shape.

(4) Evaluation of heat resistance (evaluation of hollow resin particles (G))
After holding the hollow resin particles (G) in an electric furnace set at 200 ° C. for 5 minutes, the true specific gravity was measured by the same method as in (2) above, and the heat resistance was evaluated by the true specific gravity difference before and after the heat treatment.

(5) Evaluation of heat loss temperature by TG-DTA (Evaluation of hollow resin particles (G))
The hollow resin particles (G) were evaluated by differential thermothermal gravimetric simultaneous measurement (TG-DTA) [DTG-60H: manufactured by Shimadzu Corporation] using an open type cell. From the obtained chart, the temperature when the weight was reduced by 10% by weight was defined as the 10% by weight heat loss temperature.

(6) Evaluation of total light transmittance of shell-forming resin (evaluation of hollow resin particles (G))
A monomer similar to the shell resin composition shown in Table 1 was blended, and a photopolymerization initiator [Irgacure 1000: manufactured by Ciba Specialty Chemicals] was added instead of azobisbutyronitrile. The obtained monomer was coated with an applicator to a thickness of 200 μm and exposed to UV light for 15 seconds to obtain a test substrate.
The total light transmittance of the shell-forming resin was determined by measuring the total light transmittance of the obtained test substrate using an ultraviolet-visible spectrophotometer [UV-2400PC: manufactured by Shimadzu Corporation].

The hollow resin particles obtained in the present invention (Examples 1 to 7) had high heat resistance and almost no change in specific gravity with respect to heat treatment at 200 ° C. However, the hollow resin particles (Comparative Example 2) using the conventional nitrile group-containing monomer cannot maintain the hollow shape with respect to the heat treatment (200 ° C. × 5 minutes), and a significant increase in true specific gravity is confirmed. It was.
The hollow resin particles having a crosslinked structure (Examples 1, 2, 5, 6, 7) and the hollow resin particles having a carboxyl group (Example 5) have particularly high heat resistance and a high 10% by weight heat loss temperature. Shown the temperature.
The total light transmittance is high when (meth) acrylic acid ester is used (Examples 1, 5, 6 and 7), and is low when a monomer having an aromatic ring is used (Examples 2 and 3). showed that.

The hollow resin particles of the present invention can be widely used in applications such as resin fillers, paint additives, and electronic parts.

Claims (9)

The constituent resin of the shell is a vinyl resin (A) made of a vinyl monomer (a) having no nitrile group, the true specific gravity is 0.005 to 0.1, and the volume average particle diameter is 1 to 250 μm. Hollow resin particles, characterized in that The vinyl monomer (a) having no nitrile group is at least one monomer selected from the group consisting of a monomer having a hydroxyl group, a monomer having an amino group, and a monomer having a carboxylic acid ester bond. Hollow resin particles. The hollow resin particle according to claim 1, wherein the vinyl monomer (a) having no nitrile group contains 30 mol% or less of a monomer having a carboxyl group. The hollow resin particle according to any one of claims 1 to 3, which has a 10% by weight heat loss temperature of 200 to 400 ° C. The hollow resin particle according to any one of claims 1 to 3, wherein the vinyl resin (A) is a resin having a crosslinked structure. The hollow resin particle according to claim 5, wherein the vinyl resin (A) is a poly (meth) acrylate having a crosslinked structure. The hollow resin particles according to any one of claims 1 to 3, wherein the vinyl resin (A) has a total light transmittance of 80% or more. The hollow resin particles according to claim 7, wherein the vinyl resin (A) as a constituent resin of the shell does not have an aromatic ring. Vinyl resin (A) vinyl monomer (a) having no nitrile group and phase separation accelerator (C) in solution (E) dissolved in volatile solvent (B) are converted to vinyl having no nitrile group. A liquid suspended in the solvent (D) which is insoluble in the monomer (a), the vinyl resin (A) and the volatile solvent (B) and has a boiling point higher than that of the volatile solvent (B) is polymerized under pressure. The method for producing hollow resin particles according to any one of claims 1 to 8, wherein after the vinyl resin (A) is synthesized, the pressure is released at a temperature equal to or higher than the boiling point of the volatile solvent (B).