JP2023022336A - Hollow particle, composition, member, and hollow particle production method - Google Patents

Abstract

To provide a hollow particle which, when used mixed with a binder such as a resin, can obtain a member excellent in heat insulation properties and in slipperiness, a composition, and a member.SOLUTION: A hollow particle includes a solvent having an I/O value of 0-0.300 and has a void therein.SELECTED DRAWING: None

Description

The present invention relates to hollow particles, compositions, members, and methods for producing hollow particles.

Hollow particles having a space formed therein have been used in various fields.
For example, Patent Literature 1 discloses a coating material containing hollow particles for the purpose of improving the heat insulating properties of the coating film.

Japanese Patent Application Laid-Open No. 2002-309180

On the other hand, in recent years, there has been a demand for a member containing a binder such as a resin to have not only heat insulation but also lubricity. In particular, as the lubricity, when the members (for example, resin members) are brought into contact with each other and separated, they are required to be peeled off without resistance and the property of the peeled surface does not change.
The inventors of the present invention have studied the slipperiness of a member (particularly a resin member) containing hollow particles as described in Patent Document 1, and have found that further improvement is necessary.

An object of the present invention is to provide hollow particles which, when mixed with a binder such as a resin, can be used to form a member having excellent heat insulating properties and slipperiness. and
Another object of the present invention is to provide a composition and member containing the hollow particles, and a method for producing the hollow particles.

As a result of earnestly studying the above problem, the inventors found that the above problem can be solved by the following configuration.

(1) Hollow particles encapsulating a solvent having an I/O value of 0 to 0.300 and having voids inside.
(2) The hollow particles according to (1), wherein the solvent has an I/O value of 0 to 0.100.
(3) The hollow particles according to (1) or (2), wherein the solvent content is 0.05 to 30.0% by mass with respect to the total mass of the hollow particles.
(4) The hollow particles according to any one of (1) to (3), wherein the solvent content is 0.1 to 10.0% by mass with respect to the total mass of the hollow particles.
(5) The hollow particles according to any one of (1) to (4), wherein the solvent has a boiling point of 80°C or higher and lower than 150°C.
(6) The hollow particles according to any one of (1) to (5), wherein the solvent is a hydrocarbon solvent.
(7) The hollow particles according to any one of (1) to (6), which have a porosity of 25 to 95% by volume.
(8) The hollow particles according to any one of (1) to (7), which have a volume-based median diameter of 0.5 to 500 μm.
(9) having a single-pore structure;
The hollow particle according to any one of (1) to (8), wherein the ratio of the wall thickness of the hollow particle to the volume-based median diameter of the hollow particle is 1/100 to 1/3.
(10) The hollow particle according to any one of (1) to (9), wherein the wall of the hollow particle contains at least one resin selected from the group consisting of polyurea, polyurethaneurea, and polyurethane.
(11) The hollow particle according to any one of (1) to (10), wherein the wall portion of the hollow particle has a glass transition temperature of 100 to 250°C.
(12) A composition comprising the hollow particles according to any one of (1) to (11) and a binder.
(13) A member comprising the hollow particles according to any one of (1) to (11) and a binder.
(14) A method for producing hollow particles according to any one of (1) to (11),
A method for producing hollow particles, comprising a step of mixing a solvent having an I/O value of 0 to 0.300 and a wall material of the hollow particles.

ADVANTAGE OF THE INVENTION According to this invention, the hollow particle which can obtain the member which is excellent in thermal insulation and slipperiness|lubricacy, when mixed with binders, such as resin, can be provided.
Moreover, according to the present invention, it is possible to provide a composition and a member containing the hollow particles, and a method for producing the hollow particles.

The present invention will be described in detail below.
In this specification, the numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.
In addition, in the numerical ranges described stepwise in this specification, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of the numerical range described in other steps. good. Moreover, in the numerical ranges described in this specification, the upper limit or lower limit described in a certain numerical range may be replaced with the values shown in the examples.
Various components described later may be used singly or in combination of two or more. For example, the specific solvents described below may be used singly or in combination of two or more.
As used herein, (meth)acrylate refers to acrylate and methacrylate, and (meth)acryl refers to acrylic and methacrylic.

As used herein, "wall" refers to the shell that forms the hollow particle, and "core" refers to the portion formed by the wall.
Further, in this specification, the material for forming the wall portion is referred to as "wall material".
In addition, the term “encapsulated” refers to a state in which the target is covered and confined by the walls of the hollow particles.

A feature of the hollow particles of the present invention is that they contain a solvent having an I/O value of 0 to 0.3 and have voids inside. First, the hollow particles have therein a solvent having an I/O value of 0 to 0.3, so that when the hollow particles are contained in the member, the solvent inside the hollow particles seeps out from the hollow particles. It is considered that the slipperiness of the surface of the member is improved. In addition, since the hollow particles have voids inside, they are also excellent in heat insulation.
In other words, the hollow particles of the present invention have a solvent and regions (voids) in which the solvent does not exist, and therefore can exhibit a predetermined effect.

<Hollow particles>
The hollow particles of the present invention enclose a solvent having an I/O value of 0 to 0.300 and have voids inside.
First, the hollow particles of the present invention have walls, which are outer shells that form the hollow particles. In addition, the core formed by the wall contains a solvent having an I/O value of 0 to 0.300 (hereinafter also simply referred to as "specific solvent") and voids. That is, the specific solvent is included in the hollow particles such that a part of the space formed in the wall of the hollow particles remains as voids. In other words, the hollow particles of the present invention have a wall and a specific solvent that occupies part of the space formed by being covered by the wall. That is, the hollow particles have a region occupied by the specific solvent and a region not occupied by the specific solvent.

The shape of the hollow particles is not particularly limited, and can be appropriately selected according to the application, purpose, etc. For example, any of spherical, rod-like, and plate-like shapes may be used. Above all, the particle shape is preferably spherical, more preferably spherical.
The shape of the hollow particles can be confirmed by observing the particle surface with a scanning electron microscope (for example, JSM-7800F manufactured by JEOL Ltd.).

The I/O value of the specific solvent may be from 0 to 0.300, preferably from 0 to 0.100 in terms of better slipperiness.
Here, the "I/O value" is used as one means for predicting various physicochemical properties of organic compounds. Organic properties can be obtained by comparing the number of carbon atoms, and inorganic properties can be obtained by comparing the boiling points of hydrocarbons with the same number of carbon atoms. For example, one ( _--CH.sub.2-- ) is determined to have an organic value of 20, and the inorganic value is determined to be 100 from the influence of the hydroxyl group (--OH) on the boiling point. Based on the hydroxyl group (--OH) inorganic value of 100, values of other substituents (inorganic groups) are shown in the "inorganic group table". The ratio I/O between the inorganic value (I) and the organic value (O) obtained for each molecule according to this inorganic base table is defined as the "I/O value". It shows that hydrophilicity increases as the I/O value increases, and hydrophobicity increases as the I/O value decreases.
In the present invention, the "I / O value" is the "inorganic ( I)/Organic (O)" value.

Although the boiling point of the specific solvent is not particularly limited, it is preferably 80° C. or more and less than 150° C. in terms of at least one of heat insulating property and slipperiness being more excellent (hereinafter also simply referred to as “the point at which the effects of the present invention are more excellent”). , 90 to 105° C. is more preferred.
The above boiling point is intended to be the boiling point under 1 atmosphere.

The specific solvent is not particularly limited as long as it satisfies the above I/O value, and examples thereof include hydrocarbon-based solvents, ether-based solvents, ester-based solvents, and halogen-based solvents. Among them, hydrocarbon-based solvents are preferable because the effects of the present invention are more excellent.
The number of carbon atoms (the number of carbon atoms) contained in the hydrocarbon solvent is not particularly limited, but is preferably 6 to 10, more preferably 7 to 8, from the viewpoint of better effects of the present invention.

The hydrocarbon solvent may be an aliphatic hydrocarbon solvent or an aromatic hydrocarbon solvent. Among them, aliphatic hydrocarbon solvents are preferable because the effects of the present invention are more excellent.
The aliphatic hydrocarbon solvent may be linear, branched, or cyclic. The aliphatic hydrocarbon solvent may be a saturated aliphatic hydrocarbon solvent or an unsaturated aliphatic hydrocarbon solvent.
Aliphatic hydrocarbon solvents include heptane, trimethylpentane, octane, cyclohexane, and methylcyclohexane.
Toluene is mentioned as an aromatic-hydrocarbon-type solvent.

Although the content of the specific solvent in the hollow particles is not particularly limited, it is often 50% by mass or less, and the effect of the present invention is more excellent. %, more preferably 0.1 to 10.0% by mass, and more preferably 0.2 to 5.0%.
As a method for calculating the content of the specific solvent, first, 10 mg of the hollow particles are immersed in a mixed solution of methanol and tetrahydrofuran (methanol/tetrahydrofuran = 50/50 (% by volume), 5 ml) for 24 hours, and the resulting solution is filtered. Filtrate, and use the obtained filtrate to quantify the mass of the specific solvent by gas chromatography. Next, using the quantified mass of the specific solvent, the content of the specific solvent {mass of the specific solvent/(mass of the hollow particles)×100} is calculated.

Although the porosity of the hollow particles is not particularly limited, it is preferably 25 to 95% by volume, more preferably 58 to 90% by volume, and even more preferably 58 to 80% by volume, from the viewpoint that the effects of the present invention are more excellent. The porosity means the volume ratio (% by volume) of the voids to the total volume of the hollow particles.
The porosity of the hollow particles is calculated based on image data obtained by a known X-ray CT apparatus using an X-ray Computed Tomography (X-ray Computed Tomography) method as a measurement principle. Specifically, a polyethylene terephthalate (PET) film coated with a 5% by mass aqueous solution of PVA-217E (manufactured by Kuraray Co., Ltd., polyvinyl alcohol (PVA)) as an adhesive and hollow particles attached to the sheet in the in-plane direction. An arbitrary region of 1 mm × 1 mm is scanned along the film thickness direction of the sheet by the X-ray CT method to distinguish between the gas (air) in the hollow particles and the other (solid and liquid) in the hollow particles. do. Then, from the three-dimensional image data obtained by image processing a plurality of scanning layers obtained by scanning along the film thickness direction, the volume of gas (void portion) existing in the hollow particle and the total volume of the particle (total volume of gas, solid and liquid) and The ratio of the volume of the gas (void) to the total volume of the hollow particles is defined as the porosity (volume %) of the hollow particles.

Materials constituting the walls of the hollow particles are not particularly limited, and examples thereof include polymers, more specifically, radical polymers, resins having urethane bonds and/or urea bonds, polyamides, and melamine-formaldehyde. resin.
The above materials will be described in detail below.

A radical polymer is a resin formed by radical polymerization of a monomer having a radically polymerizable double bond (ethylenically unsaturated group).
Examples of monomers (radical polymerizable monomers) from which radical polymers are derived include (meth)acrylic acid, (meth)acrylic acid esters, (meth)acrylamides, (meth)acrylic acid halides, and styrene. Radically polymerizable monomers selected from the group consisting of
(Meth)acrylic acid esters, (meth)acrylamides, (meth)acrylic acid halides, and styrenes may each independently be polyfunctional or non-polyfunctional (monofunctional). good too.

Specific examples of radically polymerizable monomers include the following monomers.
Radically polymerizable monomers having one polymerizable double bond include, for example, (meth)acrylic acid; 2-hydroxyethyl (meth)acrylate, 1-hydroxy-2-propyl (meth)acrylate, (meth)acrylate 2,3-dihydroxypropyl acrylate, hydroxymethyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and (meth)acrylate (Meth)acrylic acid esters such as benzyl acrylate; (meth)acrylamides such as acrylamide, methacrylamide, and N,N-dimethylacrylamide; acrylic acid halides such as (meth)acrylic acid chloride; styrene, hydroxystyrene , and styrenes such as dihydroxystyrene.
Examples of radically polymerizable monomers having two or more polymerizable double bonds include ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. , and (poly)alkylene glycol di(meth)acrylates such as 1,9-nonanediol di(meth)methacrylate; trimethylolpropane tri(meth)acrylate; pentaerythritol tri(meth)acrylate; dipentaerythritol penta(meth)acrylate; ) acrylate; dipentaerythritol hexa(meth)acrylate.

The radically polymerizable monomer preferably contains a polyfunctional radically polymerizable monomer (a radically polymerizable monomer having two or more polymerizable double bonds). That is, the radical polymer preferably has repeating units derived from a polyfunctional radically polymerizable monomer.
As the polyfunctional radically polymerizable monomer, radically polymerizable monomers having two or more (preferably 2 to 9, more preferably 2 to 3) polymerizable double bonds are preferred.
In the radical polymer, the content of repeating units derived from a polyfunctional radically polymerizable monomer is preferably 10% by mass or more, more preferably 20 to 98% by mass, more preferably 20 to 80% by mass, based on the total mass of the resin. % is more preferred.

Examples of resins having urethane bonds and/or urea bonds include polyurethanes, polyureas, and polyurethaneureas.

Here, polyurethane is a polymer having a plurality of urethane bonds, and is preferably a reaction product of polyol and polyisocyanate.
Polyurea is a polymer having multiple urea bonds, and is preferably a reaction product of polyamine and polyisocyanate.
Polyurethane urea is a polymer having urethane and urea bonds, preferably a reaction product of polyol, polyamine and polyisocyanate. When polyol and polyisocyanate are reacted to form polyurethane, part of polyisocyanate may react with water to form polyamine, resulting in polyurethane urea.

As noted above, polyurethanes, polyureas and polyurethaneureas are preferably formed using polyisocyanates.
Polyisocyanate is a compound having two or more isocyanate groups, and includes aromatic polyisocyanate and aliphatic polyisocyanate.
Examples of aromatic polyisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4′- Diisocyanate, 3,3'-dimethoxy-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, 4-chloroxylylene-1 ,3-diisocyanate, 2-methylxylylene-1,3-diisocyanate, 4,4′-diphenylpropane diisocyanate, and 4,4′-diphenylhexafluoropropane diisocyanate.

Examples of aliphatic polyisocyanates include trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate and cyclohexylene-1,3-diisocyanate. , cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, lysine diisocyanate, and Hydrogenated xylylene diisocyanate can be mentioned.

In the above, bifunctional aromatic polyisocyanate and aliphatic polyisocyanate were exemplified, but as polyisocyanate, trifunctional or higher polyisocyanate (e.g., trifunctional triisocyanate and tetrafunctional tetraisocyanate). mentioned.
More specifically, the polyisocyanate includes biuret or isocyanurate which is a trimer of the above bifunctional polyisocyanate, an adduct of a polyol such as trimethylolpropane and a bifunctional polyisocyanate, benzene Formalin condensate of isocyanate, polyisocyanate having a polymerizable group such as methacryloyloxyethyl isocyanate, and lysine triisocyanate can also be used.
Polyisocyanate is described in "Polyurethane Resin Handbook" edited by Keiji Iwata, published by Nikkan Kogyo Shimbun (1987).

A polyol is a compound having two or more hydroxyl groups, and examples thereof include low-molecular-weight polyols (e.g., aliphatic polyols, aromatic polyols), polyether-based polyols, polyester-based polyols, polylactone-based polyols, and castor oil-based polyols. , polyolefin-based polyols, and hydroxyl group-containing amine-based compounds.
The low-molecular-weight polyol means a polyol having a molecular weight of 300 or less, and examples thereof include bifunctional low-molecular-weight polyols such as ethylene glycol, diethylene glycol, and propylene glycol, as well as glycerin, trimethylolpropane, hexanetriol, penta Tri- or higher functional low-molecular-weight polyols such as erythritol and sorbitol.

Examples of hydroxyl group-containing amine compounds include aminoalcohols such as oxyalkylated derivatives of amino compounds. Examples of amino alcohols include N,N,N',N'-tetrakis[2-hydroxypropyl]ethylenediamine and N,N,N', which are propylene oxide or ethylene oxide adducts of amino compounds such as ethylenediamine. , N′-tetrakis[2-hydroxyethyl]ethylenediamine and the like.

Polyamines are compounds having two or more amino groups (primary amino groups or secondary amino groups), and fatty acids such as diethylenetriamine, triethylenetetramine, 1,3-propylenediamine, and hexamethylenediamine. polyvalent amine; polyalkyleneimine (preferably polyethyleneimine); epoxy compound adduct of aliphatic polyvalent amine; alicyclic polyvalent amine such as piperazine; 3,9-bis-aminopropyl-2,4, Heterocyclic diamines such as 8,10-tetraoxaspiro-(5,5)undecane are included.
Polyalkyleneimine is a polymer having repeating units consisting of an amine and an alkylene group, and polyethyleneimine having repeating units consisting of an amine and an ethylene group is preferred.

Polyamides include, for example, aliphatic polyamides and aromatic polyamides.
Polyamide is preferably a resin obtained by polymerizing polyamine (diamine, etc.), polycarboxylic acid (dicarboxylic acid, etc.) and/or polycarboxylic acid halide (dicarboxylic acid halide, etc.), for example.
Examples of polycarboxylic acid halides include polycarboxylic acid chlorides (dicarboxylic acid chlorides, etc.).
The polycarboxylic acid may be a carboxylic acid anhydride in which carboxylic acid groups are dehydrated and condensed.
Polyamide is a polyamine, polycarboxylic acid, and polycarboxylic acid halide in which more than 50% by mass (preferably 75 to 100% by mass, more preferably 90 to 100% by mass) of the total mass of the resin is bonded with an amide bond. It is preferably a repeating unit derived from.

A diamine is preferable as the polyamine from which the repeating units in the polyamide are derived. Polyamines include, for example, aliphatic polyamines, alicyclic polyamines, and aromatic polyamines. Diamines include, for example, aliphatic diamines, alicyclic diamines, and aromatic diamines.

As the aliphatic diamine or alicyclic diamine, for example, a diamine represented by the following general formula (A) can be used. R ₁ in the following formula represents an aliphatic or alicyclic alkylene group represented by C _n H _2n (n=1 to 12).
H ₂ N—R ₁ —NH ₂ (A)
Aromatic diamines include, for example, xylylenediamine and meta-xylylenediamine.

The polycarboxylic acid from which the repeating units of the polyamide are derived is preferably a dicarboxylic acid.
Dicarboxylic acids include, for example, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids.
As the aliphatic dicarboxylic acid or alicyclic dicarboxylic acid, for example, a dicarboxylic acid represented by the following general formula (B) can be used. R ₂ in the following formula represents an aliphatic or alicyclic alkylene group represented by C _n H _2n (n=4 to 25).
HOOC-R ₂ -COOH (B)
Aliphatic dicarboxylic acids include, for example, adipic acid.
Aromatic dicarboxylic acids include, for example, terephthalic acid, methyl terephthalic acid, naphthalenedicarboxylic acid, and isophthalic acid.
As the aromatic dicarboxylic acid, for example, terephthalic acid or isophthalic acid is preferable because it can exhibit excellent properties even at high temperatures.

The polycarboxylic acid halide (polycarboxylic acid chloride, etc.) from which the repeating unit of the polyamide resin is derived is preferably a dicarboxylic acid halide (dicarboxylic acid chloride, etc.).
Examples of the dicarboxylic acid halide include compounds in which the carboxyl group (-COOH) in the above dicarboxylic acid is replaced with a carboxylic acid halide group (-COX, X represents a halogen atom, preferably a chlorine atom).

From the viewpoint that the effects of the present invention are more excellent, the wall preferably contains at least one resin selected from the group consisting of polyurea, polyurethaneurea, and polyurethane.

The glass transition temperature of the wall portion is not particularly limited, but is preferably 100 to 250°C, more preferably 150 to 220°C, from the standpoint that the effects of the present invention are more excellent.
A method for measuring the glass transition temperature of the wall portion is as follows.
The glass transition temperature of the measurement material is measured using a differential scanning calorimeter DSC (device name: DSC-60A Plus, Shimadzu Corporation), using a closed pan, and heating at a rate of 5 ° C./min from 25 ° C. to ( Thermal decomposition temperature (°C) -5°C). As the glass transition temperature of the wall portion, the value at the time of temperature rise in the second cycle is used.

Although the volume-based median diameter of the hollow particles is not particularly limited, it is preferably 0.5 to 500 μm, more preferably 5 to 250 μm, and even more preferably 10 to 150 μm, from the viewpoint that the effects of the present invention are more excellent.
Here, the volume-based median diameter of the hollow particles means that when the whole hollow particles are divided into two with the particle size as a threshold, the total number of particles on the large diameter side and the small diameter side is equal. The diameter (diameter where the larger side and the smaller side are equal). The volume-based median diameter of the hollow particles is measured by a laser diffraction/scattering method using LA-920 (Horiba, Ltd.).

The hollow particles may have a single-pore structure (single-nuclear structure) or a porous structure (multi-nuclear structure). Among them, the hollow particles preferably have a single-pore structure in order to obtain a more excellent effect of the present invention.
In this specification, the term "single-pore structure" refers to a structure in which the core formed by the walls has only one closed space, and the term "porous structure" refers to the structure formed by the walls. A structure in which the core is partitioned into a plurality of partitions and spaces are provided in the partitioned portions.

When the hollow particles have a single pore structure, the ratio of the wall thickness of the hollow particles to the volume-based median diameter of the hollow particles (hollow particle wall thickness/volume-based median diameter of the hollow particles) is particularly limited. Although not required, it is preferably 1/100 to 1/3 in that the effect of the present invention is more excellent.

The wall thickness (wall thickness) of the hollow particles is not particularly limited, but is preferably 0.1 to 50 μm, more preferably 0.5 to 20 μm, and more preferably 1 to 10 μm in terms of the effect of the present invention. More preferred.
The wall thickness refers to the average value obtained by averaging the individual wall thicknesses (μm) of 20 hollow particles with a scanning electron microscope (SEM).
Specifically, it is obtained by the following method. First, a liquid in which hollow particles are dispersed is applied onto an arbitrary support and dried to form a coating film. A cross-sectional section of the obtained coating film was prepared, and the cross section was observed with an SEM at a magnification of 100 to 5000, and "(value of median diameter based on volume of hollow particles) × 0.9 ~ (volume based on hollow particles value of the median diameter) × 1.1”, and then observe the cross section of each selected hollow particle to obtain the thickness of the wall, The number average wall thickness (μm) of the hollow particles is determined by arithmetically averaging 20 numerical values from the minimum value.

<Method for producing hollow particles>
The method for producing hollow particles is not particularly limited, and examples thereof include known methods such as an interfacial polymerization method, an internal polymerization method, a phase separation method, an external polymerization method, and a coacervation method. Among them, the interfacial polymerization method is preferable.
The hollow particle manufacturing method preferably includes a step of mixing a solvent having an I/O value of 0 to 0.300 and a wall material of the hollow particles. If necessary, a step of obtaining hollow particles may be carried out by partially removing the enclosed solvent from the particles containing the solvent inside obtained in the above step.
An interfacial polymerization method using a polyisocyanate compound will be described below as an example.

As a method for producing hollow particles, a step of dispersing an oil phase containing at least a polyisocyanate compound and a specific solvent in an aqueous phase to prepare a dispersion (hereinafter referred to as a dispersion step), and a heat treatment of the dispersion. , a step of polymerizing at least a polyisocyanate compound to form a wall portion to obtain particles containing a specific solvent (hereinafter referred to as a particle formation step), and a heat treatment to partially remove the specific solvent from the particles, thereby forming a hollow and a step of forming particles (hereinafter referred to as a hollow particle forming step).
Each step will be described in detail below.

(Dispersion process)
In the dispersing step, an oil phase containing a polyisocyanate compound and a specific solvent is dispersed in an aqueous phase to prepare a dispersion.
As the dispersion liquid, an emulsion liquid emulsified using an emulsifier may be prepared. When preparing an emulsion, it can be prepared by dispersing an oil phase containing at least a specific solvent and a polyisocyanate compound as a wall material in an aqueous phase containing an emulsifier.

The oil phase contains at least a polyisocyanate compound that is a wall material and a specific solvent, and may contain at least one of a polyol and a polyamine. Also, if desired, the oil phase may further contain other ingredients such as co-solvents and additives.

The aqueous phase preferably contains at least an aqueous solvent, and more preferably contains at least an aqueous solvent and an emulsifier.
The aqueous medium includes water and a mixed solvent of water and alcohol, and ion-exchanged water can be used.

Emulsifying agents include dispersing agents or surfactants, or combinations thereof.
Dispersants include, for example, polyvinyl alcohol and its modified products (eg, anion-modified polyvinyl alcohol), polyacrylic acid amide and its derivatives, ethylene-vinyl acetate copolymer, styrene-maleic anhydride copolymer, ethylene-anhydride Maleic acid copolymer, isobutylene-maleic anhydride copolymer, polyvinylpyrrolidone, ethylene-acrylic acid copolymer, vinyl acetate-acrylic acid copolymer, carboxymethylcellulose, methylcellulose, casein, gelatin, starch derivatives, gum arabic, and sodium alginate, preferably polyvinyl alcohol.

Surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

The concentration of the emulsifier is preferably more than 0% by mass and 20% by mass or less, more preferably 0.005 to 10% by mass, still more preferably 0.01 to 10% by mass, with respect to the total mass of the emulsion, and 0.3 ~3% by weight is particularly preferred.

The aqueous phase may optionally contain other ingredients such as UV absorbers, antioxidants and preservatives.

Dispersion refers to dispersing an oil phase in the form of oil droplets in an aqueous phase, and includes emulsifying the aqueous phase with an emulsifier (for example, a surfactant).
Dispersion can be carried out using a means commonly used for dispersing an oil phase and an aqueous phase, such as a homogenizer, a Manton-Gourie, an ultrasonic disperser, a dissolver, a keddy mill, or other known dispersing device.

The mixing ratio of the oil phase to the water phase (oil phase/water phase; mass basis) is preferably 0.05 to 1.2, more preferably 0.1 to 0.7.

(Particulation process)
In the granulating step, the dispersion liquid obtained in the dispersing step is heat-treated to polymerize at least the polyisocyanate compound to form a wall portion, thereby obtaining particles encapsulating the specific solvent.
By the heat treatment, the polyisocyanate compound is polymerized at the oil-water interface in the dispersion to form a wall portion, and the specific solvent is included as a core component.

In this step, at least a polyisocyanate compound is polymerized. Polymerization is carried out by polymerizing the wall material contained in the oil phase in the dispersion at the interface with the water phase. This forms a wall (shell). At this time, a dispersion is prepared in which particles containing an oil phase are dispersed in an aqueous phase.
In forming the wall portion, the dispersion liquid is subjected to a heat treatment. The temperature for heat treatment is usually preferably 40 to 100°C, more preferably 50 to 90°C.
The heating time is preferably 0.5 to 10 hours, more preferably 1 to 5 hours.

In order to prevent particles from aggregating during polymerization, it is preferable to further add an aqueous solution (eg, water, acetic acid aqueous solution, etc.) to lower the collision probability between particles, and it is also preferable to perform sufficient stirring. A dispersant for preventing aggregation may be added again during the polymerization.
In addition, a charge control agent such as nigrosine, or any other adjuvant may be added, if desired. The adjuvant can be added during wall formation or at any time.

(Hollow particle forming step)
In the hollow particle forming step, after the wall portions are formed in the particle forming step, heat treatment is further performed to partially remove the specific solvent from the particles formed in the particle forming step. As a result, hollow particles encapsulating the specific solvent and having voids are obtained.

When the particles are heat-treated, it is preferable to first remove the aqueous medium in the dispersion liquid prepared in the particle-forming step, and then heat-treat the particles.
Specifically, it is preferred that the dispersion is filtered to separate the aqueous medium from the particles and powdered, and that the obtained powder is subjected to heat treatment. As a result, the particles containing the specific solvent (that is, the precursor particles of the hollow particles) taken out from the dispersion are heated, and part of the specific solvent contained in the particles is efficiently released to the outside through the wall of the particles. is released to This allows the formation of hollow particles.
It is preferable not to use a spray dryer when separating the particles from the dispersion and pulverizing them.

As for the heating temperature for the heat treatment, an optimum temperature is selected according to the type of the specific solvent.
Among them, the heating temperature is preferably 80 to 210° C., more preferably 120 to 170° C., in terms of easy production of hollow particles.
As for the heating temperature during the heat treatment, the optimum time is selected according to the type of the specific solvent.
Among them, the heating time is preferably 1 to 24 hours, more preferably 3 to 12 hours, in terms of easy production of hollow particles.
The heat treatment may be performed under reduced pressure conditions (eg, vacuum conditions). The pressure reduction condition is preferably 20 Torr or less.

The heat treatment can be performed using a known heater, such as a hot air heater (dryer), an oven, an infrared heater, or the like.
Moreover, commercially available powder dryers (eg, vibration dryer manufactured by Chuo Kakoki Co., Ltd., conical ribbon mixer/dryer manufactured by Okawara Seisakusho, etc.) can also be used.

<Composition, member>
The hollow particles of the present invention can be used in combination with a binder. The member containing the hollow particles of the present invention can achieve both heat resistance and slipperiness.

The type of binder that can be combined with the hollow particles is not particularly limited, and may be organic or inorganic. A resin is preferable as the organic substance.
The type of resin is not particularly limited, and known resins may be used. Examples of resins include thermoplastic resins and curable resins (thermosetting resins and photocurable resins).
Examples of thermoplastic resins include styrene-based resins, (meth)acrylic-based resins, polycarbonate-based resins, polyester-based resins, polyolefin-based resins, polyamide-based resins, polyphenylene ether-based resins, polyimide-based resins, polyacetal-based resins, and polysulfone-based resins. Resins, fluorine-based resins, and vinyl chloride-based resins can be mentioned.
Thermosetting resins include, for example, phenol-based resins, melamine-based resins, urea-based resins, benzoguanamine-based resins, silicone-based resins, epoxy-based resins, and polyurethane-based resins.
Examples of photocurable resins include photocurable polyester resins and photocurable (meth)acrylic resins.
The resin to be combined with the hollow particles is preferably the same kind of resin as the resin contained in the wall of the hollow particles, because the adhesion between the resin and the hollow particles is more excellent. Specifically, when the resin contained in the walls of the hollow particles is a polyurethane-based resin, the resin to be combined with the hollow particles is preferably a polyurethane-based resin.

Binders include ceramic raw materials, concrete, mortar, and cement in addition to resins.

The composition of the present invention contains the hollow particles and a binder.
Although the mixing ratio of the hollow particles and the binder in the composition of the present invention is not particularly limited, the ratio of the total mass of the hollow particles to the total mass of the binder is 0.01 in view of the superior effect of the present invention. ~40% by mass is preferable, and 0.5 to 20% by mass is more preferable.

The composition of the present invention may contain components other than the hollow particles and binder described above.
Other components include, for example, solvents, surfactants, stabilizers (thermal stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, etc.), gloss modifiers, fillers, dispersants, coupling agents, adhesives Applicants, antistatic agents, colorants, flame retardants, and lubricants are included.
The method for producing the composition of the present invention is not particularly limited, and includes known methods. For example, the composition can be produced by mixing hollow particles, a binder, and optionally other components by stirring or the like.

The composition of the present invention can be applied to various uses.
For example, it is used to manufacture members to be described later.
When producing a member described later, for example, a method of applying a composition containing hollow particles, a binder, and a solvent and performing a drying treatment as necessary, and a method of kneading the hollow particles into the binder and molding A member having a predetermined shape can be produced by the method of
In addition, when the binder is a curable resin, for example, a coating film formed by applying a composition containing hollow particles, a curable resin, and a solvent, or hollow particles are kneaded into a curable resin and molded. Curing treatment (thermal curing treatment and photocuring treatment) may be performed on the molded product.

The member of the present invention is a member containing hollow particles and a binder. Descriptions of the hollow particles and binder are provided above. As the member, a resin member containing hollow particles and resin is preferable.
The shape of the member of the present invention is not particularly limited and includes any particular shape desired. Specifically, flat plate shape, curved plate shape, rod shape, cylindrical shape, and block shape are mentioned. In addition, the shape of a flat plate includes the shape of a film and the shape of a sheet. The film shape means a film shape with a thickness of less than 250 μm, and the sheet shape means a thin plate shape with a thickness of 250 μm or more.
The shape of the surface of the member of the present invention is not particularly limited, and is not limited to a single flat surface and curved surface, and may have various shapes such as stepped portions, concave portions, and convex portions.

When the member of the present invention is flat, the thickness of the member is not particularly limited, and is often 1 µm or more. Although the upper limit is not particularly limited, it is preferably 1000 μm or less, more preferably 500 μm or less, from the viewpoint of thinning.

The method for manufacturing the member of the present invention is not particularly limited, and includes known methods. For example, as described above, a method using the composition of the present invention containing a solvent is included.

The compositions and members of the present invention can be applied to various uses. For example, it can be applied to applications requiring not only heat insulation and lubricity but also low refractive index, low dielectric constant, light weight, heat insulation, high electrical resistance, sound absorption and machinability.
The composition of the present invention can be used as a raw material for paints and shaped articles.
For example, the member (preferably resin member) of the present invention can be used as a semiconductor polishing pad, a coating support, a heat insulating sheet, a heat insulating material, a light diffusion sheet, a sound absorbing material, an electrical insulating member, a friction material, and the like. can.
In addition to the applications described above, the composition and member of the present invention can also be applied to mobile devices such as personal computers, ships, transportation vehicles, aerospace applications, and the like.
Moreover, in the composition and member of the present invention, the hollow particles can also function as a pore former. That is, pores can be formed in the molding by leaving the hollow particles themselves as they are or by removing the hollow particles by thermal decomposition. Therefore, the composition and member of the present invention can also be applied to ceramic filters, civil engineering concrete, ceramic artificial bones, shock absorbing films, and the like.

Also, the member of the present invention may be used in combination with other materials.
For example, since the resin member of the present invention has excellent heat insulating properties, in a laminate obtained by arranging the resin member of the present invention and a thermosensitive recording layer adjacent to each other, a thermal head is brought close to the surface side of the thermosensitive recording layer. Since the heat from the thermal head does not easily pass through the resin member, the heat tends to stay in the thermosensitive recording layer, thereby improving the recording performance.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

<Example 1>
Ethyl acetate (50 parts by mass), heptane (50 parts by mass), and Barnock (registered trademark) D-750, which is an aromatic polyisocyanate as a wall material (manufactured by DIC Corporation, tolylene diisocyanate trimethylolpropane adduct; polyfunctional isocyanate compound) (43 parts by mass) and ADEKA polyether EPD-300 (manufactured by ADEKA Corporation, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine; polyether polyol) (0.4 parts by mass) and were stirred and mixed to obtain an oil phase.
Next, a 1% by mass aqueous solution of Kuraray Poval (registered trademark) KL-318 (manufactured by Kuraray Co., Ltd., polyvinyl alcohol (PVA); emulsifier) was prepared. An oil phase was added to this aqueous solution (500 parts by mass) and emulsified and dispersed for 4 minutes at a rotation speed of 1000 rpm (revolutions per minute) to prepare an emulsion (emulsion dispersion) (dispersion step). After emulsification and dispersion, the prepared emulsion was heated to 70° C. to polymerize the aromatic polyisocyanate at the oil-water interface to form a wall (shell), thereby obtaining an aqueous dispersion of microcapsules (particles process). The volume-based median diameter (D50) of the microcapsules in the obtained aqueous dispersion was 98 μm.
Subsequently, the aqueous dispersion of microcapsules obtained above was filtered through a nylon mesh to dehydrate, and further heat-treated in a vacuum dry oven at 160°C for 8 hours to form hollow particles (hollow particle formation process). The obtained hollow particles contained heptane and had voids inside the hollow particles.
The volume-based median diameter (D50) of the hollow particles was 98 μm.
Further, when the glass transition temperature (Tg) of the wall of the hollow particles was measured using a differential scanning calorimeter (DSC-60A, manufactured by Shimadzu Corporation) by the method described above, it was 210°C. .
A method for measuring heptane contained in the hollow particles is as follows.
10 mg of the resulting hollow particles were immersed in a mixed solution of methanol and tetrahydrofuran (methanol/tetrahydrofuran = 50/50 (% by volume), 5 ml) for 24 hours, the resulting solution was filtered, and the obtained filtrate was used. The mass of heptane entrapped in the hollow particles was quantified by gas chromatography.

In addition, in the obtained cross-sectional observation view of the hollow particles, the ratio of the area obtained by dividing the wall area of the hollow particles from the total area of the hollow particles to the total area of the hollow particles is calculated according to the method described above. It was measured.

<Example 2>
Hollow particles were produced according to the same procedure as in Example 1, except that heptane was changed to trimethylpentane.

<Example 3>
Same as Example 1 except that heptane was changed to n-octane and "heat treatment in a vacuum dry oven at 160 ° C. for 8 hours" was changed to "heat treatment in a vacuum dry oven at 180 ° C. for 8 hours". Hollow particles were produced according to the procedure.

<Example 4>
Hollow particles were produced according to the same procedure as in Example 1, except that heptane was changed to toluene.

<Example 5>
Following the same procedure as in Example 1, except that heptane was changed to cyclohexane, and "heat treatment in a vacuum dry oven at 160°C for 8 hours" was changed to "heat treatment in a vacuum dry oven at 160°C for 4 hours". , to produce hollow particles.

<Example 6>
Hollow particles were produced according to the same procedure as in Example 1, except that heptane was changed to methylcyclohexane.

<Example 7>
Hollow particles were produced according to the same procedure as in Example 2, except that "heat treatment in a vacuum dry oven at 160°C for 8 hours" was changed to "heat treatment in a vacuum dry oven at 160°C for 3 hours".

<Example 8>
The number of revolutions in the dispersion process was changed from 1000 rpm to 2000 rpm, and "heat treatment in a vacuum dry oven at 160 ° C. for 8 hours" was changed to "heat treatment in a vacuum dry oven at 180 ° C. for 24 hours". ) Hollow particles were produced in the same manner as in Example 2, except that 86 parts by mass of D-750 (tolylene diisocyanate trimethylolpropane adduct; polyfunctional isocyanate compound manufactured by DIC Corporation) was added.

<Example 9>
Hollow particles were produced according to the same procedure as in Example 2, except that the rotation speed in the dispersion step was changed from 1000 rpm to 2000 rpm.

<Example 10>
Hollow particles were produced according to the same procedure as in Example 1, except that "heat treatment in a vacuum dry oven at 160°C for 8 hours" was changed to "heat treatment in a vacuum dry oven at 160°C for 1 hour".

<Comparative Example 1>
Hollow particles were produced according to the same procedure as in Example 1, except that "heat treatment in a vacuum dry oven at 160°C for 8 hours" was changed to "heat treatment in a vacuum dry oven at 180°C for 72 hours".

<Comparative Example 2>
The same procedure as in Example 1, except that heptane was changed to ethyl butyrate, and "heat treatment in a vacuum dry oven at 160°C for 8 hours" was changed to "heat treatment in a vacuum dry oven at 160°C for 4 hours". Hollow particles were produced according to

<Comparative Example 3>
Hollow particles were produced according to the same procedure as in Example 1, except that "heat treatment in a vacuum dry oven at 160°C for 8 hours" was changed to "heat treatment in a vacuum dry oven at 100°C for 2 hours".

It was confirmed that the hollow particles obtained in Examples 1 to 10 had voids inside. The hollow particles obtained in Comparative Example 3 did not have voids inside.
In Examples 1 to 10 and Comparative Examples 1 to 3, the air pressure in the vacuum dry oven during heating was all 20 Torr or less.

<Evaluation>
(Slipperiness evaluation (Part 1))
The mixture obtained by mixing the hollow particles (10 parts by mass) obtained in Example 1 with Liquid A (45 parts by mass) and Liquid B (45 parts by mass) of Resin Cast EX (manufactured by Wave) The liquid was put into a mold to prepare a resin film 1 having a thickness of 200 μm.
Instead of the hollow particles obtained in Example 1, the hollow particles obtained in Examples 2 to 7, 9 to 10, and Comparative Examples 1 to 3 were used, respectively, and resin films 2 to 2 were prepared in the same manner as described above. 7, 9-10, and resin films C1-C3 were obtained.

Next, a sample film having a length of 5 cm and a width of 5 cm was cut out from the obtained resin film 1, two of the obtained sample films were superimposed, and a weight of 1 kg was placed on the obtained laminate.
Next, while the weight was placed on the laminate, the laminate was left in a constant temperature bath at a temperature of 45° C. and a humidity of 75% for 3 days. After that, remove the weight from the laminate and observe whether or not there is resistance when separating the two superimposed sample films, and also observe the state of the contact surfaces of the sample films. was evaluated at normal temperature according to the criteria of When the slipperiness is poor, as shown in "C" described later, there is resistance when separating the sample film, and the state of the surface in contact with the sample film (for example, optics and roughness) changes. .
"A": There was no resistance when the sample film was separated, and there was no change in the state of the contact surface of the sample film.
"B": There was resistance when the sample film was separated, but there was no change in the state of the contact surface of the sample film.
"C": There was resistance when the sample film was separated, and the state of the contact surface of the sample film changed.

Instead of resin film 1, resin films 2 to 7, 9 to 10, and resin films C1 to C3 were used, respectively, and the above (slipperiness evaluation (part 1)) was carried out.

(Slipperiness evaluation (Part 2))
The mixture obtained by mixing the hollow particles (20 parts by mass) obtained in Example 8 with Liquid A (50 parts by mass) and Liquid B (50 parts by mass) of Resin Cast EX (manufactured by Wave) The liquid was put into a mold to produce a resin film 8A having a thickness of 20 μm.
Next, resin cast EX (manufactured by Wave Co., Ltd.) A solution (50 parts by mass) and B solution (50 parts by mass) are mixed, and the resulting mixed solution is applied on the resin film 8A to obtain The film was put into a mold to prepare a resin film 8 having a thickness of 200 μm.
That is, the resin film 8 was a laminated film of the resin film 8A and the resin film 8B formed from the resin cast EX.

Next, a sample film of 5 cm long and 5 cm wide was cut out of the obtained resin film 8, and the resin films 8A and 8B were superimposed so that they were in contact with each other, and a weight of 1 kg was placed on the resulting laminate. was placed.
Next, while the weight was placed on the laminate, the laminate was left in a constant temperature bath at a temperature of 45° C. and a humidity of 75% for 3 days. After that, remove the weight from the laminate and observe whether there is resistance when separating the two superimposed sample films, and observe the state of the contact surfaces of the sample films. It was evaluated at room temperature according to the same criteria as in the evaluation of slipperiness (part 2)).

(Heat insulation evaluation)
A coating solution for a heat-sensitive recording layer was prepared according to paragraphs 0103 to 0132 of Japanese Patent No. 4076676.
In addition, a protective layer coating solution was prepared according to paragraphs 0098 to 0100 of Japanese Patent No. 4076676.
The surface of resin film 1 prepared in the above (evaluation of slipperiness) was subjected to corona treatment, and the thermosensitive recording layer coating liquid was applied onto the corona-treated surface of resin film 1 in an amount of 11.5 g/dry. After drying to form a thermosensitive recording layer, the protective layer coating liquid was applied onto the thermosensitive recording layer so that the dry coating amount was 2.5 g/m ^{2 .} , resin film 1, a heat-sensitive recording layer, and a heat-sensitive recording material having a protective layer.

Using a thermal head (trade name: KGT, 260-12MPH8, manufactured by Kyocera Corporation), a head pressure of 10 kg/cm ² and a recording energy of 60 mJ/mm ² were used for thermal recording from the protective layer side of the resulting thermal recording material. Layers were recorded. Thereafter, the heat insulating properties of the resin film 1 were evaluated by measuring the color density of the obtained heat-sensitive recording material using a reflection densitometer. It means that the higher the color density, the higher the heat insulating property of the resin film 1 .
"A": When the color density is 2.0 or more "B": When the color density is 1.5 or more and less than 2.0 "C": When the color density is 1.0 or more and less than 1.5 "D": Color density Less than 1.0

Instead of the resin film 1, the resin films 2 to 10 and the resin films C1 to C3 were used, respectively, and the above (thermal insulation evaluation) was carried out.
However, when the resin film 8 was used, the heat-sensitive recording layer and the protective layer were arranged on the surface of the resin film 8 on the resin film 8A side, and the above evaluation was carried out.

In Table 1, "content (%)" in the "specific solvent" column represents the content (% by mass) of the specific solvent contained in the hollow particles with respect to the total mass of the hollow particles.
In Table 1, "void ratio (%)" in the "hollow particles" column represents the ratio (% by volume) of voids in the hollow particles to the total volume of the hollow particles, and the measurement method is as described above.
In Table 1, the "hollow particles/resin (%)" column in the "resin member" column represents the ratio (% by mass) of the total mass of the hollow particles to the total mass of the resin.
In Table 1, "A" in the "Configuration" column means that the structure of the resin member is a single layer structure containing hollow particles, and "B" means that the structure of the resin member is a layer containing hollow particles and a layer containing hollow particles. It means that it is a laminated structure with a layer that does not contain

As shown in the table above, the use of the hollow particles of the present invention produced the desired effects.
Among them, from the comparison of Examples 1, 7 and 10, when the content of the specific solvent in the hollow particles is 0.05 to 30.0% by mass (preferably 0.1 to 10.0% by mass), It was confirmed that the effect is superior.
Moreover, it was confirmed from the comparison of Examples 1 to 4 that the effect is more excellent when the I/O value of the solvent is 0 to 0.100.

Claims (14)

Hollow particles encapsulating a solvent having an I/O value of 0 to 0.300 and having voids inside. The hollow particles according to claim 1, wherein the solvent has an I/O value of 0 to 0.100. 3. The hollow particles according to claim 1, wherein the content of the solvent is 0.05 to 30.0% by mass with respect to the total mass of the hollow particles. The hollow particles according to any one of claims 1 to 3, wherein the content of the solvent is 0.1 to 10.0% by mass with respect to the total mass of the hollow particles. The hollow particles according to any one of claims 1 to 4, wherein the solvent has a boiling point of 80°C or higher and lower than 150°C. Hollow particles according to any one of claims 1 to 5, wherein the solvent is a hydrocarbon solvent. Hollow particles according to any one of claims 1 to 6, having a porosity of 25 to 95% by volume. The hollow particles according to any one of claims 1 to 7, wherein the hollow particles have a volume-based median diameter of 0.5 to 500 µm. having a single-pore structure,
The hollow particle according to any one of claims 1 to 8, wherein the ratio of the wall thickness of the hollow particle to the volume-based median diameter of the hollow particle is 1/100 to 1/3. Hollow particles according to any one of claims 1 to 9, wherein the walls of the hollow particles comprise at least one resin selected from the group consisting of polyurea, polyurethaneurea and polyurethane. The hollow particle according to any one of claims 1 to 10, wherein the wall portion of the hollow particle has a glass transition temperature of 100 to 250°C. A composition comprising the hollow particles according to any one of claims 1 to 11 and a binder. A member comprising the hollow particles according to any one of claims 1 to 11 and a binder. A method for producing hollow particles according to any one of claims 1 to 11,
A method for producing hollow particles, comprising a step of mixing a solvent having an I/O value of 0 to 0.300 and a wall material of the hollow particles.