JP6993775B2 - Organic polymer fine particles - Google Patents

Description

The present invention relates to organic polymer fine particles composed of a crosslinked (meth) acrylic polymer.

Resin films are widely used as various packaging materials. When the resin films are stored in a roll form or in a stacked state, the films may be blocked from each other, making it difficult to slip or peel off. An anti-blocking agent is used as an additive for preventing such blocking. In addition, when it is simply referred to as a film in this specification, it means a resin film unless otherwise specified.

Resin fine particles are widely used as an anti-blocking agent from the viewpoint of maintaining the transparency of the film and suppressing scratches. As such resin fine particles, Patent Document 1 describes organic polymer fine particles containing a sulfur-based antioxidant. Further, Patent Document 2 does not contain impurities such as decomposition products of 2,2'-azobisisobutyronitrile (AIBN), and the amount of (meth) acrylic monomer remaining in the fine particles is 2000 ppm or less. (Meta) acrylic crosslinked fine particles are described. Further, Patent Document 3 describes organic polymer fine particles containing at least one type of bifunctional or higher polyfunctional monomer (crosslinking agent).

Japanese Patent No. 5572383 Japanese Patent No. 40341157 Japanese Unexamined Patent Publication No. 2010-275356

However, when the conventional resin fine particles are used as an anti-blocking agent for a film, the frictional resistance between the films may increase and the anti-blocking property may decrease when the friction between the films is repeated. The present invention has been made in view of such circumstances, and an object thereof is to increase the frictional resistance between films even if the films are repeatedly rubbed against each other when used as an anti-blocking agent for films. It is an object of the present invention to provide the organic polymer fine particles which can be suppressed.

The present inventors reduce the Al content while suppressing the tendency of the surface of the organic polymer fine particles to become hydrophilic, and further contain a specific antioxidant or a component derived from the specific antioxidant in the particles to prevent the film from being rubbed. We have found that the frictional resistance between films does not increase even if the friction between the films is repeated by further increasing the compression deformation recovery rate of the organic polymer fine particles that can suppress the falling off of the fine particles. Completed the invention.

According to the study by the present inventors, the conditions of suspension polymerization were adjusted, and the reaction solution obtained without using an aluminum-based flocculant was separated into solid and liquid to recover the organic polymer fine particles. It is possible to obtain organic polymer fine particles having a reduced Al content and an increased hydrophobicity on the surface of the fine particles. Usually, an aluminum-based flocculant such as aluminum sulfate is indispensable for recovering fine particles from the reaction suspension. This is because if this is not used, it will be practically difficult to recover the fine particles. However, since the addition of a flocculant is natural and not a feature, even if a flocculant is used, its use is rarely specified. The present invention is characterized in that the description of the use of a flocculant such as aluminum sulfate is not omitted, and the flocculant is not intentionally used.

The present invention includes the following inventions.
[1] A (meth) acrylic polymer crosslinked with a crosslinkable monomer.
The structural unit based on the crosslinkable monomer is 5% by mass or more and 40% by mass or less.
The following sedimentation start time is 10 seconds or more,
The Al content measured by radio frequency inductively coupled plasma (ICP) emission spectroscopy is 1 ppm or less.
Organic polymer fine particles containing 0.2% by mass or more of a hindered phenolic antioxidant or a component derived from the same, and having a compression deformation recovery rate of 6% or more.
[Settling start time]
Prepare a glass container with a cross-sectional area of 5 cm ² or more and 10 cm ² or less filled with 20 mL of deionized water at a liquid temperature of 20 ° C., and gently float 0.02 ± 0.005 g of organic polymer fine particles on the water surface. The time until the first particle starts to settle is defined as the settling start time.
[2] The organic polymer fine particles according to [1], wherein the mass average particle diameter is 1.0 μm or more and 15 μm or less.
[3] The organic polymer fine particles according to [1] or [2] used as an anti-blocking agent for a film.
[4] A master batch containing the organic polymer fine particles according to any one of [1] to [3] and a resin.
[5] A resin film containing the organic polymer fine particles according to any one of [1] to [3] and a resin.
[6] A laminated film containing at least one layer of the resin film according to [5] and a base film.

In the organic polymer fine particles of the present invention, the Al content is reduced while the tendency of surface hydrophilicity is suppressed, a specific antioxidant or a component derived from the specific antioxidant is contained in the particles, and the compression deformation recovery rate is high. Therefore, when used as an anti-blocking agent for films, it is possible to suppress an increase in frictional resistance between films even if friction between the films is repeated.

FIG. 1 is a scanning electron microscope image (magnification magnification 500 times) showing protrusions and dropout marks derived from organic polymer fine particles on the surface of a resin film.

1. 1. Organic Polymer Fine Particles The organic polymer fine particles of the present invention are formed from a (meth) acrylic polymer crosslinked with a crosslinkable monomer, and increase the hydrophobicity of the surface to reduce the Al content, and are specific. Since it contains an antioxidant or a component derived from it and has a higher compression deformation recovery rate, when used as an anti-blocking agent for films, even if the films are repeatedly rubbed against each other, the friction between the films The increase in resistance can be suppressed.

Specifically, the organic polymer fine particles of the present invention have the following settling start time of 10 seconds or more. When the settling start time is 10 seconds or more, the organic polymer fine particles show high hydrophobicity and are suppressed from falling off from the film.
[Settling start time]
Prepare a glass container with a cross-sectional area of 5 cm ² or more and 10 cm ² or less filled with 20 mL of deionized water at a liquid temperature of 20 ° C., and gently float 0.02 ± 0.005 g of organic polymer fine particles on the water surface. The time until the first particle starts to settle is defined as the settling start time.

When the organic polymer fine particles are floated on the water surface, they can be gently floated on the water surface by placing them on a spatula and placing the particles on the water surface near the water surface. Further, the start of sedimentation is the timing at which the first particles of the organic polymer fine particles floating on the water surface begin to sink.
Further, the sedimentation start time shall be measured at least twice and the average thereof shall be taken.

The density of the organic polymer fine particles is higher than that of water, for example, 1.05 g / cm ³ or more, preferably 1.1 g / cm ³ or more, and more preferably 1.15 g / cm ³ or more. The upper limit of the density is, for example, 1.3 g / cm ³ or less, preferably 1.2 g / cm ³ or less. Further, the particle diameter may be based on a spherical shape such as a true sphere, a porous body, a protrusion, or an ellipse, and the particle surface may be modified to the extent that the performance is not impaired.

Although the organic polymer fine particles of the present invention are heavier than water, they float on the water surface for a long time, so that it can be said that the hydrophobicity is enhanced and the organic polymer fine particles are suppressed from falling off from the resin film. The settling start time is preferably 16 seconds or longer, more preferably 20 seconds or longer, still more preferably 25 seconds or longer, and particularly preferably 60 seconds or longer.

Further, since the Al content contained in the organic polymer fine particles of the present invention is reduced, the residual hydrated water can be suppressed and the surface can be maintained more hydrophobic. Therefore, the Al content is 1 ppm or less, more preferably 0.5 ppm or less, still more preferably 0.1 ppm or less.
The Al content can be measured by radio frequency inductively coupled plasma (ICP) emission spectroscopy.

The amount of the hindered phenol-based antioxidant or a component derived from the hindered phenol-based antioxidant in the organic polymer fine particles is 0.2% by mass or more, preferably 0.25% by mass or more, and more preferably 0.35% by mass or more. It is preferably 2% by mass or less, more preferably 1% by mass or less, and further preferably 0.6% by mass or less.

By including a specific antioxidant or a component derived from the antioxidant in the organic polymer fine particles, it becomes easy to suppress the organic polymer fine particles from falling off from the film. Further, the hindered phenol-based antioxidant or a component derived thereof may be a component in which the antioxidant used during the polymerization of the organic polymer fine particles remains in the organic polymer fine particles, and after the organic polymer fine particles are polymerized, the antioxidant may remain. It may be mixed with a hindered phenol-based antioxidant or a component derived from the hindered phenol-based antioxidant at an appropriate stage (for example, after particle drying).

The amount of the hindered phenol-based antioxidant or its derived component in the organic polymer fine particles is, for example, the organic polymer fine particles are pulverized by an appropriate means as necessary, and then an appropriate organic solvent (chloroform, etc.) is used. It can be determined by extracting a hindered phenolic antioxidant or a component derived from it and quantitatively analyzing it using chromatography or the like.

The compression deformation recovery rate of the organic polymer fine particles of the present invention is 6% or more, preferably 8% or more, more preferably 9.5% or more, preferably 20% or less, more preferably 15% or less. More preferably, it is 12% or less. By increasing the compression deformation recovery rate of the organic polymer fine particles, it is possible to suppress the increase in frictional resistance due to friction between the films when used as an anti-blocking agent, and by suppressing it to an appropriate range, the film It is possible to maintain close contact with.

The compression deformation recovery rate is an index of the ease of returning the shape (restorability) when the particles are compressed, and the following formula compression deformation recovery rate (%) = (particle recovery rate / particle compression rate) ×. 100
It is represented by. The particle restoration rate and the particle compression rate are indicators of the ease of returning the shape (restorability) when the particles are compressed, and can be calculated by a load unloading test. Specifically, the maximum displacement amount (L1) when the load is applied to the particles and compressed, and the displacement amount (L2) when the load is removed (unloaded) from the particles are used to obtain the following equations, respectively. be able to.
Particle restoration rate (%)
= (Displacement return amount (L2-L1) / Mass average particle size before load unloading test) × 100
Particle compression rate (%)
= (Maximum displacement (L1) / Mass average particle size before load unloading test) x 100
The maximum displacement amount (L1) can be measured as the displacement amount (μm) when the load reaches 1 gf when the organic polymer fine particles are loaded at a load rate of 0.2275 gf / sec, and can be measured at the time of unloading. The displacement amount can be measured as the displacement amount (μm) at the time when the load becomes 0.01 gf after unloading from the state of the load 1 gf at a unloading speed of 0.2275 gf / sec with the holding time at the load 1 gf as 0 second. ..

The water content of the organic polymer fine particles is preferably 1% by mass or less. The water content can be measured by the Karl Fischer method.

The content of the sulfur element in the organic polymer fine particles is preferably 300 ppm or less, more preferably 200 ppm or less, further preferably 100 ppm or less, still more preferably 10 ppm or less, and less than 1 ppm in terms of the amount of sulfur atoms. Is particularly preferable.

The organic polymer fine particles of the present invention are (meth) acrylic polymers crosslinked with a crosslinkable monomer (hereinafter, may be referred to as “crosslinked (meth) acrylic polymer”), and are (meth) acrylic monomers (meth). Structural unit based on A) (hereinafter, may be referred to as "(meth) acrylic monomer (A) unit") and structural unit based on crosslinkable monomer (B) (hereinafter, "crosslinkable monomer (B) unit") It is preferable to have.).

As the (meth) acrylic monomer (A), one kind or two or more kinds can be used, and (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl. (Meta) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate , 2-Ethylhexyl (meth) acrylate, dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, isotridecyl (meth) acrylate, tetradecyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) Examples thereof include monoalkyl (meth) acrylates such as acrylates, behenyl (meth) acrylates and dodecylpentadecyl (meth) acrylates; and monocyclic ether-containing acrylates such as tetrahydrofurfuryl (meth) acrylates.
As the (meth) acrylic monomer (A), monoalkyl (meth) acrylates are preferable, and at least methyl (meth) acrylate is preferably contained from the viewpoint of easy formation of particles. Further, as the (meth) acrylic monomer, a methacrylic monomer is preferable.

The (meth) acrylic monomer (A) is a monomer in which an alkyl group having 1 to 3 carbon atoms is bonded to a (meth) acryloyloxy group (hereinafter referred to as "alkyl (meth) acrylate-based monomer (A1)". ) And a monomer in which an alkyl group having 4 or more carbon atoms is bonded to a (meth) acryloyloxy group (hereinafter, may be referred to as “alkyl (meth) acrylate-based monomer (A2)”). Is preferable.

Examples of the alkyl (meth) acrylate-based monomer (A1) include monomers having 1 to 3 carbon atoms among the monoalkyl (meth) acrylates exemplified as the (meth) acrylic-based monomer (A), and methyl (meth) acrylate-based monomers. ) Acrylate is preferred. Further, the (meth) acryloyl group of the alkyl (meth) acrylate-based monomer is preferably a methacryloyl group.

The ratio of the structural unit based on the alkyl (meth) acrylate-based monomer (A1) (hereinafter, may be referred to as “alkyl (meth) acrylate-based monomer (A1) unit”) is the copolymer constituting the organic polymer fine particles. Of the above, it is preferably 20% by mass or more, more preferably 25% by mass or more, further preferably 30% by mass or more, particularly preferably 35% by mass or more, and preferably 80% by mass or less, more preferably. Is 70% by mass or less, more preferably 65% by mass or less.

Examples of the alkyl (meth) acrylate-based monomer (A2) include monomers having 4 or more carbon atoms among the monoalkyl (meth) acrylates exemplified as the (meth) acrylic-based monomer (A). In the alkyl (meth) acrylate-based monomer (A2), the number of carbon atoms of the alkyl group bonded to the (meth) acryloyloxy group is 4 or more, preferably 6 or more, more preferably 8 or more, and preferably 24 or less. , More preferably 18 or less, still more preferably 12 or less, even more preferably 8 or less, and particularly preferably 6 or less.
The (meth) acryloyl group of the alkyl (meth) acrylate-based monomer (A2) is preferably a methacryloyl group.

In the copolymer constituting the organic polymer fine particles, the alkyl (meth) acrylate-based monomer (A2) unit is preferably 3% by mass or more, more preferably 10% by mass or more, still more preferably 20. It is preferably by mass or more, particularly preferably 25% by mass or more, preferably 70% by mass or less, more preferably 65% by mass or less, still more preferably 60% by mass or less, and particularly preferably 55% by mass or less. be. The larger the number of alkyl (meth) acrylate-based monomer (A2) units, the easier it is to reduce the residual monomer.

The alkyl (meth) acrylate-based monomer (A2) unit is 5 parts by mass or more out of 100 parts by mass in total of the alkyl (meth) acrylate-based monomer (A1) unit and the alkyl (meth) acrylate-based monomer (A2) unit. It is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, preferably 80 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 60 parts by mass or less. Particularly preferably, it is 50 parts by mass or less.

The crosslinkable monomer (B) that crosslinks the crosslinked (meth) acrylic polymer has two groups having a polymerizable ethylene bond in one molecule (hereinafter, may be referred to as “polymerizable ethylene bond-containing group”). In the monomer having the above, the number of groups having a polymerizable ethylene bond contained in one molecule is preferably 2 to 6, more preferably 2 to 3, and particularly preferably 2. Examples of the polymerizable ethylene bond-containing group include a vinyl group, a (meth) acryloyl group, and the like, preferably a (meth) acryloyl group, and more preferably a methacryloyl group.

Further, it is preferable that the two or more polymerizable ethylene bond-containing groups are bonded via a chain (preferably linear) hydrocarbon chain in the crosslinkable monomer (B). When the polymerizable ethylene bond-containing group is a (meth) acryloyl group, the (meth) acryloyl group forms an ester bond with a diol compound such as an alkylene glycol; a triol compound; and a polyol compound such as a tetraol compound. Is more preferable. As the polyol compound, alkylene glycols such as ethylene glycol, butanediol, hexanediol and nonanediol are preferable, and ethylene glycol is particularly preferable.

Among the crosslinkable monomers (B), the bifunctional crosslinkable (meth) acrylic monomers include ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,6-hexanediol di (1,6-hexanediol di). Alcandiol di (meth) acrylates such as meta) acrylates and 1,9-nonanediol di (meth) acrylates; alkene di (meth) acrylates such as 1,3-butylenedi (meth) acrylates; polyethylene glycol di (meth) acrylates ( The number of repetitions of the ethylene glycol unit is, for example, 2 to 150); and the like. Examples of the trifunctional crosslinkable (meth) acrylic monomer include trimethylolpropane tri (meth) acrylate, and examples of the tetrafunctional crosslinkable (meth) acrylic monomer include pentaerythritol tetra (meth) acrylate. Examples of the hexafunctional crosslinkable (meth) acrylic monomer include dipentaerythritol hexa (meth) acrylate. These monomers may be used alone or in combination of two or more.

As the crosslinkable monomer (B), a 2 to 6 functional crosslinkable (meth) acrylic monomer is preferable, a 2 to 4 functional crosslinkable (meth) acrylic monomer is more preferable, and a bifunctional crosslinkable (meth) acrylic monomer is more preferable. It is a (meth) acrylic monomer, and an alkanediol di (meth) acrylate is particularly preferable.

When the number of polymerizable ethylene bond-containing groups contained in the crosslinkable monomer (B) is 2, the number of elements constituting the shortest straight chain between the two polymerizable ethylene bonds is the compression of the organic polymer fine particles. From the viewpoint of facilitating the increase in the deformation recovery rate, it is preferably 15 or less, more preferably 9 or less, still more preferably 7 or less, preferably 2 or more, and more preferably 3 or more. The number of oxygen atoms contained in these elements is preferably 4 or less, more preferably 3 or less, and preferably 2 or more. Further, from the viewpoint of improving the hydrophobicity, it is preferable that the number of oxygen atoms contained in one molecule of the crosslinkable monomer (B) is small.

The ratio of the crosslinkable monomer (B) unit is 5% by mass or more, 40 in the copolymer (crosslinked (meth) acrylic polymer) constituting the organic polymer fine particles, from the viewpoint of facilitating the increase in the compression deformation recovery rate. It is mass% or less, preferably 35% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

The total of the (meth) acrylic monomer (A) unit and the crosslinkable monomer (B) unit is preferably 90% by mass or more, more preferably 95% by mass or more, and further, in the copolymer constituting the organic polymer fine particles. It is preferably 98% by mass or more.

Further, the organic polymer fine particles of the present invention have styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene and α- as other monomers (C) that can be copolymerized with the above-mentioned (meth) acrylic monomer. Styrene-based monomers such as methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, ethylvinylbenzene; m-divinylbenzene, p. -Aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof, cross-linking agents such as N, N-divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfonic acid, polybutadiene and JP-A-57-56507. One or 2 of the reactive polymers described in JP-A-59-221304, JP-A-59-221305, JP-A-59-221306, JP-A-59-221307, etc. It may contain more than seeds. The other monomer (C) is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 2% by mass or less in all the monomers constituting the organic polymer fine particles.

The mass average particle diameter (Dw) of the organic polymer fine particles of the present invention is preferably 0.5 μm or more, more preferably 1.0 μm or more, still more preferably 2.0 μm or more, preferably 40 μm or less, and more preferably. It is 30 μm or less, more preferably 15 μm or less, particularly preferably 10 μm or less, and most preferably 8 μm or less.
When the organic polymer fine particles of the present invention are used for the resin film, it is preferable to change the particle size according to the thickness of the resin film, and the mass average particle size of the organic polymer fine particles is 10 times or less the thickness of the resin film (preferably). Is 7 times or less, more preferably 6 times or less), and although the lower limit is not particularly limited, it may be 1 time or more (preferably 1.5 times or more, more preferably 2 times or more).
By setting the value of the mass average particle diameter of the organic polymer fine particles with respect to the thickness of the resin film in the above range, it is possible to suppress the falling off of the particles from the film while suppressing the friction coefficient. The fine particles contaminate the film manufacturing apparatus and can reduce the adverse effects on the productivity of the film and the transparency of the produced film.

The ratio (Dn / Dw) of the number average particle diameter (Dn) and the mass average particle diameter (Dw) of the organic polymer fine particles is, for example, 0.3 or more, preferably 0.4 or more, and 0.6. It may be a higher value than this. Dn / Dw is an index of monodispersity of the particle size. The higher the value, the smaller the proportion of fine particles, and the closer to 1, the more monodisperse the particles. By bringing Dn / Dw closer to 1, it is possible to more appropriately prevent the particles from falling off. The upper limit of Dn / Dw is, for example, 1 or less, and may be 0.9 or less.

The coefficient of variation (CV value) of the particle size of the organic polymer fine particles is a value obtained from the mass-based particle size distribution, and is preferably 50% or less, more preferably 45% or less, still more preferably 40% or less. It is preferably 10% or more, more preferably 20% or more, still more preferably 30% or more, and particularly preferably 35% or more. The CV value represents the particle size distribution, and by making this value appropriate, it is possible to more appropriately prevent the particles from falling off.

The particle size can be measured by a precision particle size distribution measuring device using the Coulter principle (for example, "Coulter Multisizer Type III" manufactured by Beckman Coulter). The particle size is measured as a mass average particle size (Dw) and a number average particle size (Dn), and the coefficient of variation (CV value) of the mass-based particle size can be calculated according to the following formula.
Coefficient of variation (%) of average particle size (Dw) = (standard deviation σ of particle size / average particle size (Dw)) × 100

In addition, in order to keep the particle size (Dw, Dn), the ratio (Dn / Dw), the coefficient of variation (CV value), etc. of the organic polymer fine particles within a predetermined range, classification may be performed as necessary. As the classification, either wet classification or dry classification can be used. Wet classification is possible, for example, by passing the polymerized liquid after polymerization through a metal mesh, and dry classification is performed by using an appropriate classifying device for the particles after polymerization, further drying and crushing. It can be carried out.

The organic polymer fine particles of the present invention contain a hindered phenolic antioxidant or a component derived from the hindered phenolic antioxidant while suppressing the tendency of surface hydrophilicity to reduce the Al content, and the compression deformation recovery rate is enhanced. ing. Therefore, it is possible to suppress an increase in frictional resistance between films, and it is suitably used as an anti-blocking agent, lubricant and the like for various films.

2. 2. Method for Producing Organic Polymer Fine Particles In the organic polymer fine particles of the present invention, the (meth) acrylic monomer (A) and the crosslinkable monomer (B) are suspended in the presence of a polymerization initiator and an antioxidant. It can be produced by polymerizing and recovering the polymer by solid-liquid separation without adding at least an aluminum-based flocculant.

Here, what is important for achieving a predetermined hydrophobicity (precipitation start time of 10 seconds or more) is to allow an antioxidant to coexist while suppressing the amount of the polymerization initiator.
By suppressing the amount of the polymerization initiator, the amount of the reaction residue of the residual polymerization initiator can be suppressed, and the hydrophobicity of the obtained polymer fine particles can be improved. Further, by suppressing the amount of the polymerization initiator and allowing the antioxidant to coexist, the polymerization reaction is suppressed, and the polymerization of the (meth) acrylic monomer (A) and the crosslinkable monomer (B) is facilitated evenly. , The tendency of the surface of the obtained organic polymer fine particles to become hydrophilic is suppressed.
Therefore, the polymerization initiator is 2.5 parts by mass or less, more preferably 1.8 parts by mass, based on 100 parts by mass of the total of the (meth) acrylic monomer (A) and the crosslinkable monomer (B). Hereinafter, it is more preferably 1.6 parts by mass or less, particularly preferably 1.5 parts by mass or less, 0.1 parts by mass or more, and preferably 0.2 parts by mass or more.
The antioxidant is preferably 0.1 part by mass or more, more preferably 0.2 part by mass, based on 100 parts by mass of the total of the (meth) acrylic monomer (A) and the bifunctional crosslinkable monomer (B). As described above, it is particularly preferably 0.3 parts by mass or more, 1 part by mass or less, and more preferably 0.7 parts by mass or less.

Further, in the present invention, at least an aluminum-based flocculant is not added when recovering the obtained organic polymer fine particles, and usually, the flocculant itself containing the aluminum-based flocculant is not added. The flocculant is usually used when recovering fine particles from a fine particle suspension, and even in a fine particle suspension in which fine particles are dispersed in a solvent and difficult to recover by solid-liquid separation, the fine particles are aggregated and settled. It is possible to increase the recovery rate of fine particles. However, in the present invention, it has been found that the hydrophobicity of the surface of the organic polymer fine particles can be enhanced by intentionally not using this flocculant.
Well-known and commonly used aluminum-based flocculants that are specifically avoided in use in the present invention include, for example, aluminum salts such as aluminum chloride, aluminum sulfate, polyaluminum chloride, and polyaluminum hydroxide; aluminum complexes. ; Etc.

Hereinafter, the method for producing the organic polymer fine particles of the present invention will be described separately for each step.
In the case of suspension polymerization, first, the above (meth) acrylic monomer (A), the crosslinkable monomer (B), and, if necessary, another monomer (C) are dispersed and suspended with a solvent. A monomer suspension can be obtained (hereinafter, the step of dispersing and suspending the monomer and the solvent may be referred to as a "particle regulation step"). By polymerizing the monomers in the obtained monomer suspension, a suspension of organic polymer fine particles can be obtained.

As the polymerization initiator, one kind or two or more kinds can be used, a radical polymerization initiator (particularly a thermal polymerization initiator) is preferable, and benzoylper oxide, lauroylper oxide, octanoylper oxide, orthochlorobenzoylper. Oxide, orthomethoxybenzoylperoxide, diisopropylperoxydicarbonate, cyclohexanone peroxide, t-hexylperoxy-2-ethylhexanoate (trade name: perhexyl O (registered trademark)), 1,1-di (t-). Hexylperoxy) Cyclohexane (trade name: Perhexa HC (registered trademark)), cumenehydroperoxide, t-butylhydroperoxide, methylethylketone peroxide, diisopropylbenzenehydroperoxide and other peroxide-based polymerization initiators; 2, 2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,3-dimethylbutyronitrile), 2,2'-azobis- (2-Methylbutyronitrile), 2,2'-azobis (2,3,3-trimethylbutyronitrile), 2,2'-azobis (2-isopropylbutyronitrile), 1,1'-azobis ( Cyclohexane-1-carbonitrile), 2,2'-4-methoxy-2,4-dimethylvaleronitrile), 2- (carbamoylazo) isobutyronitrile, 4,4'-azobis (4-cyanovalerolic acid), Examples thereof include azo compound-based polymerization initiators such as dimethyl-2,2'-azobisisobutyrate; Of these, peroxide-based polymerization initiators are preferable.

The 10-hour half-life temperature of the polymerization initiator is preferably 40 to 90 ° C, more preferably 40 to 80 ° C, still more preferably 50 to 70, from the viewpoint of controlling the polymerization reaction and removing the polymerization initiator by raising the temperature. It is preferably in the range of ° C.

When two or more kinds of the polymerization initiators are combined, it is preferable to combine the polymerization initiators having different 10-hour half-life temperatures from the viewpoint of facilitating the progress of the polymerization.
When combining polymerization initiators having different 10-hour half-life temperatures, the range of the 10-hour half-life temperature of the polymerization initiator having the lowest 10-hour half-life temperature is preferably 40 to 80 ° C, more preferably 50 to 70 ° C. More preferably, it is 50 to 65 ° C. Specific examples include lauryl peroxide (10-hour half-life temperature 61.6 ° C.).
The difference in 10-hour half-life temperature between the polymerization initiator having the highest 10-hour half-life temperature and the polymerization initiator having the lowest 10-hour half-life temperature is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, still more preferably 15 ° C. or higher. For example, when lauryl peroxide (10-hour half-life temperature 61.6 ° C.) is used as the polymerization initiator having the lowest 10-hour half-life temperature, t-hexylperoxy is used as the polymerization initiator having the highest 10-hour half-life temperature. -2-Ethylhexanoate (trade name: Perhexyl O (registered trademark)) (10-hour half-life temperature 69.9 ° C.), 1,1-di (t-hexyl peroxy) cyclohexane (trade name: Perhexa HC (trade name) Registered trademark)) (10-hour half-life temperature 87.1 ° C.) and the like can be selected.

By coexisting with an antioxidant, the heat resistance of the obtained organic polymer fine particles can be improved. The antioxidant preferably contains a radical scavenging agent, and preferably contains at least a hindered phenolic antioxidant.
The hindered phenolic antioxidant is an antioxidant having a structure in which a bulky organic group such as a tert-butyl group is substituted at the ortho position of phenol, and has an action of capturing radicals. By coexisting with a hindered phenolic antioxidant, it becomes easy to increase the hydrophobicity of the particles, and it is possible to prevent the particles from falling off from the film to a higher degree.

If an antioxidant having a radical scavenging action is used, the progress of the polymerization reaction is hindered. Therefore, it is usually necessary to increase the amount of the polymerization initiator in order to proceed with the polymerization reaction. In the present invention, the hydrophobicity of the organic polymer fine particles is enhanced by intentionally reducing the amount of the polymerization initiator.

Specific examples of the hindered phenolic antioxidant include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (trade name: Irganox (registered trademark) 1010). ), Octadecyl-3- (3,5-di-tert-butyl-1-hydroxyphenyl) propionate, N, N'-hexane-1,6-diylbis [3- (3,5-di-tert-butyl) -4-Hydroxyphenyl) propionamide], benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4-hydroxy, C7-C9 side chain alkyl ester, 3,3', 3 ", 5, 5', 5 "-hexa-tert-butyl-a, a', a"-(mesitylen-2,4,6-tolyl) tri-p-cresol, calcium diethylbis [[[3,5-bis (1) , 1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate], ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylenebis [3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5- Triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5 -Triazine-2,4,6 (1H, 3H, 5H) -trione, reaction product of N-phenylbenzeneamine and 2,4,4-trimethylbenzene, diethyl [[3,5-bis (1,1) -Dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, 2,4-dimethyl-6- (1-methylpentadecyl) phenol, octadecyl-3- (3,5-tert-butyl-4-hydroxyphenyl) propionate , 2', 3-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] propionohydrazide and the like;

The hindered phenolic antioxidant is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, still more preferably 90 parts by mass or more, and particularly preferably 95 parts by mass or more, based on 100 parts by mass of the total amount of the antioxidant. Most preferably, it is 98 parts by mass or more and 100 parts by mass or less.
The hindered phenolic antioxidant is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, still more preferably 0.4 parts by mass or more, based on 100 parts by mass of the total amount of the monomer. It may be preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and further preferably 2 parts by mass or less. By regulating the amount of the hindered phenolic antioxidant itself with respect to the monomer, the amount of the hindered phenolic antioxidant in the organic polymer fine particles can be adjusted.

It is desirable to use the hindered phenolic antioxidant in a specific range as compared with the above-mentioned polymerization initiator. The ratio of the hindered phenolic antioxidant to the polymerization initiator (hindered phenolic antioxidant / polymerization initiator) is preferably 0.2 or more, preferably 0.25 or more, more preferably 0.3 or more. It is even more preferably 0.4 or more, preferably 10 or less, preferably 7 or less, more preferably 5 or less, and even more preferably 2 or less. By regulating the amount of the hindered phenolic antioxidant with respect to the polymerization initiator, the amount of the hindered phenolic antioxidant in the polymer particles can be adjusted, and the heat resistance of the organic polymer fine particles can be improved. It can be increased more reliably.

The antioxidant may further contain a phosphorus-based antioxidant, a lactone-based antioxidant, a hydroxyamine-based antioxidant, a vitamin E-based antioxidant, and the like. Examples of the phosphorus-based antioxidant include tris (2,4-di-tert-butylphenyl) phosphite and tris [2-[[2,4,8,10-tetra-tert-butyldibenzo [d, f]]. [1,3,2] dioxaphosfefin-6-yl] oxy] ethyl] amine, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis [2,4-bis (2,4-bis) 1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphite, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite Etc .; Examples of the lactone-based antioxidant include a reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene (CAS No. 181314-48-7); reduction. Hydroxamine-based antioxidants such as alkylamine oxidation products made from beef fat; 3,4-dihydro-2,5,7,8-tetramethyl-2- (4,8,12-trimethyltridecyl) ) -Vitamin E-based antioxidants such as -2H-benzopyran-6-ol can be mentioned.

Further, it is preferable that the antioxidant does not contain a sulfur-based antioxidant. By not using a sulfur-based antioxidant, the generation of odor can be suppressed.

The dispersion stabilizer may be either an organic dispersion stabilizer or an inorganic dispersion stabilizer. Examples of the organic dispersion stabilizer include water-soluble polymers, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric ionic surfactants, alginate, zein, casein and the like. Examples of the inorganic dispersion stabilizer include barium sulfate, calcium sulfate and the like, barium carbonate, magnesium carbonate, calcium phosphate, talc, clay, silica soil, bentonite, titanium hydroxide, thorium hydroxide, metal oxide powder and the like.

Examples of the water-soluble polymer include water-soluble polymers such as polyvinyl alcohol, gelatin, tragant, starch, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, sodium polyacrylate, and sodium polymethacrylate.
Examples of the anionic surfactant include fatty acid salts such as sodium oleate and potassium castor oil; alkyl sulfate esters such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; alkylnaphthalene sulfonic acid. Salt; Alcan sulfonate; Dialkyl sulfosuccinate; Alkyl phosphate ester salt; Naphthalene sulfonic acid formalin condensate; Polyoxyalkylene alkyl ether sulfate such as polyoxyethylene alkyl ether sulfate; Polyoxyethylene phenyl ether sulfate ester salt Such as polyoxyalkylene aryl ether sulfate ester salt; polyoxyalkylene alkyl sulfate ester salt such as polyoxyethylene alkyl sulfate ester salt; and the like.
Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate; and quaternary ammonium salts such as lauryltrimethylalkylammonium chloride.
Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, and glycerin fatty acid ester. Examples thereof include oxyethylene-oxypropylene block copolymer.
Examples of the zwitterionic surfactant include lauryldimethylamine oxide and the like.
Among them, anionic surfactant is preferable, and polyoxyalkylene aryl ether sulfate is more preferable, from the viewpoint of good polymerization stability and suspension stability.

In the particle regulation step, the surfactant used is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and preferably 5 parts by mass or less, based on 100 parts by mass of the total amount of the monomer. It is more preferably 3 parts by mass or less, still more preferably 2 parts by mass or less.

As the solvent, an aqueous solvent is preferable. The aqueous solvent may be water alone or a combination of water and a non-aqueous solvent. From the viewpoint of suspension stability, it is preferable to contain a sufficient amount of water. The amount of water is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, still more preferably 95 parts by mass or more, and particularly preferably 99 parts by mass or more in 100 parts by mass of the aqueous solvent.

As the non-aqueous solvent, a water-soluble organic solvent is preferable. By using a non-aqueous solvent (particularly a water-soluble organic solvent), the particle size of the obtained particles can be controlled. Examples of the water-soluble organic solvent include alcohol solvents such as methanol, ethanol, 1-propanol, 1-butanol, 2-propanol, 2-methylpropyl alcohol and 2-methyl-2-propanol; and ketones such as acetone and methyl ethyl ketone. Solvents; ester solvents such as ethyl acetate; ether solvents such as dioxane, diethyl ether, tetrahydrofuran; and the like.

Further, in the particle regulation step, the solvent is preferably 100 parts by mass or more, more preferably 120 parts by mass or more, still more preferably 135 parts by mass with respect to 100 parts by mass of the solid content (component obtained by removing the solvent from the monomer suspension). It is by mass or more, preferably 200 parts by mass or less, more preferably 160 parts by mass or less, and further preferably 150 parts by mass or less. After the particle regulation step, additional solvent may be added if necessary.

The order of adding the surfactant, the monomer, the polymerization initiator, the antioxidant, and the solvent is not particularly limited, but for example, the solvent and the surfactant are mixed first, and then the monomer, the polymerization initiator, and the antioxidant are mixed. It is preferable to do so. Further, it is preferable to dissolve the polymerization initiator and the antioxidant in the monomer in advance.

An emulsification / dispersion device can be used to disperse and suspend these monomers, polymerization initiators, antioxidants, and if necessary, solvents and dispersion stabilizers. Examples of the emulsification / dispersion device include Milder (manufactured by Ebara Corporation), T.I. K. High-speed shear turbine type disperser such as homomixer (manufactured by Primix Co., Ltd.); High-pressure jet homogenizer such as piston type high-pressure homogenizer (manufactured by Gorin), Microfluidizer (manufactured by Microfluidix Co., Ltd.); Ultrasonic homogenizer Ultrasonic emulsification disperser (manufactured by Nissei Tokyo Office), etc .; Medium stirring disperser such as Atwriter (manufactured by Mitsui Mine Co., Ltd.); Forced gap such as colloid mill (manufactured by Nissei Tokyo Office Co., Ltd.) A pass-through type disperser or the like can be used. Prior to the above dispersion and suspension, pre-stirring may be performed with a normal paddle blade or the like.

The stirring speed at the time of the above dispersion and suspension is, for example, T.I. K. When Homomixer MARK II model 2.5 (manufactured by Primix Corporation) is used, 4000 rpm or more is preferable, and 5000 rpm or more is more preferable. A desired particle size can be obtained by appropriately setting the stirring time. The stirring time is the above T.I. K. When using the homomixer MARK II model 2.5, it is preferably 5 to 30 minutes. Further, when the stirring time is within the above range, it is possible to prevent the liquid temperature from rising, and it becomes easy to control the polymerization reaction.

The polymerization temperature is preferably 40 to 100 ° C, more preferably 50 to 90 ° C. The polymerization temperature can be appropriately adjusted depending on the type of the polymerization initiator used, and is preferably, for example, a temperature 2 to 4 ° C. higher than the 10-hour half-life temperature of the polymerization initiator used. The 10-hour half-life temperature is a temperature that serves as a guide for the decomposition of the polymerization initiator. However, if the polymerization temperature is within the above range, the decomposition of the polymerization initiator proceeds moderately, and the polymerization initiator remains in the obtained particles. At the same time as the amount is reduced, the polymerization stability is also good. In particular, when the polymerization initiator used is lauryl peroxide, the 10-hour half-life temperature of lauryl peroxide is 62 ° C., so that the polymerization temperature is preferably 64 to 66 ° C.

The polymerization time is preferably 5 to 600 minutes, more preferably 10 to 300 minutes. When the polymerization time is within the above range, the degree of polymerization can be appropriately increased and the mechanical properties of the particles can be improved. The polymerization atmosphere is preferably an inert atmosphere such as a nitrogen atmosphere or a noble gas atmosphere.

The organic polymer fine particles are recovered by cooling the obtained suspension of the organic polymer fine particles to 50 ° C. or lower and performing solid-liquid separation substantially without adding a flocculant. The aggregating agent is preferably 0.005 parts by mass or less, more preferably 0.001 parts by mass or less, still more preferably 0.0005 parts by mass or less, and particularly preferably 0. It is 0002 parts by mass or less, most preferably 0 parts by mass.
As the solid-liquid separation method, the optimum method can be selected from filtration, centrifugation, and a combination thereof.

The obtained organic polymer fine particles are preferably dried. The drying temperature is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, preferably 90 ° C. or lower, and more preferably 80 ° C. or lower. The drying time is preferably 10 hours or more and 20 hours or less, and more preferably 12 hours or more and 18 hours or less. The longer the drying time, the easier it is to dry, and the shorter the drying time, the more the coloring of the particles can be suppressed.

Further, the dried organic polymer fine particles may be crushed if necessary. The crushing is preferably performed at 10 to 40 ° C., and the crushing pressure is preferably 0.1 to 0.5 MPa.

3. 3. Masterbatch As described above, the organic polymer fine particles of the present invention are suppressed from falling off from the resin and are useful as additives for resins, and the masterbatch containing the organic polymer fine particles of the present invention and the resin is also within the scope of the present invention. include. Since the organic polymer fine particles of the present invention have a high affinity with the resin, the blending amount of the organic polymer fine particles with respect to the resin can be increased, and the organic polymer fine particles can be obtained by processing the organic polymer fine particles into a master batch. The blending amount of the organic polymer fine particles in the resin composition or the resin film can be easily adjusted, the dispersed state of the organic polymer fine particles can be made more uniform, and the segregation of the organic polymer fine particles can be suppressed.

As the resin used in the masterbatch, a resin classified as a thermoplastic resin can be used. Examples of the thermoplastic resin include polyester resin; polyolefin resin; polyamide resin; polyurethane resin; (meth) acrylic resin; polycarbonate resin; polystyrene resin and the like. Among these, polyolefin resin is preferable. Examples of the polyolefin resin include polyethylene, polypropylene, poly (4-methylpentene) and the like, and polypropylene is preferable. Polypropylene resins mainly include homopolymers consisting only of polypropylene, and random copolymers obtained by copolymerizing polypropylene (preferably 95% by mass or more) and a small amount (preferably 5% by mass or less) of ethylene. In the case of the polypropylene resin of the present invention, the present invention refers to all polypropylene resins having improved physical properties by copolymerizing with these two types or other propylenes and the like. Among them, a polypropylene resin in which the proportion of the unit derived from propylene is preferably 90% by mass or more, more preferably 95% by mass or more is preferable.

The resin is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 85% by mass or more, and preferably 99% by mass or less, more preferably 99% by mass or more in the master batch. It is 95% by mass or less.

The content of the organic polymer fine particles in the master batch is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, and further preferably 5 parts by mass or more with respect to 100 parts by mass of the resin in the master batch. It is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, further preferably 20 parts by mass or less, and further preferably 15 parts by mass or less.

The masterbatch of the present invention preferably further contains an antioxidant. The antioxidant can be selected from the above-exemplified range, and a hindered phenol-based antioxidant and a phosphorus-based antioxidant are preferable. In particular, the total of the hindered phenolic antioxidant and the phosphorus-based antioxidant is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 95% by mass or more in the antioxidant. It is 98% by mass or more.
Further, the hindered phenol-based antioxidant is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, still more preferably 40 to 60% by mass in the antioxidant.

Further, the antioxidant is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 0.8 part by mass or more, and preferably 0.8 part by mass or more, based on 100 parts by mass of the resin in the master batch. Is 7 parts by mass or less, more preferably 4 parts by mass or less, still more preferably 2 parts by mass or less, and particularly preferably 1.5 parts by mass or less.

As a method for preparing a masterbatch, for example, a method of adding and mixing polymer particles at the polymerization step of synthesizing a resin; a method of melting and mixing the polymerized resin with an extruder or the like; a method of dissolving the resin in a solvent. A method of adding and mixing the polymer particles in the above-mentioned state; and the like. Among these, a method of melt-mixing is preferable because it is easy to produce a resin composition in which the organic polymer fine particles are dispersed and contained in a high concentration.
The prepared masterbatch is usually processed into powder or pellets.

4. Fine particle-containing resin film and resin composition A resin film containing the organic polymer fine particles of the present invention and a resin (hereinafter, may be referred to as “fine particle-containing resin film”) is also included in the scope of the present invention. Since the organic polymer fine particles of the present invention are those in which hydrophilization is suppressed and the Al content is reduced, by using this, the organic polymer fine particles are used even during film production and after film rubbing. It is possible to obtain a fine particle-containing resin film in which the dropout of the film is suppressed.

The resin used for the fine particle-containing resin film (hereinafter, also referred to as “matrix resin”) can be selected from the range exemplified as the resin used for the masterbatch. When the resin film is produced after being processed into a masterbatch, the matrix resin may be the same as or different from the resin used for the masterbatch.

The organic polymer fine particles contained in the fine particle-containing resin film are preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and preferably 10% by mass. % Or less, more preferably 5% by mass or less, still more preferably 2% by mass or less.

Further, the organic polymer fine particles of the present invention are suppressed from falling off from the fine particle-containing resin film during molding of the fine particle-containing resin film. The dropout of particles from the fine particle-containing resin film can be evaluated by the following dropout rate.
Dropout rate (%) = Dropout number / (particle number + dropout number)

Here, the number of dropouts is obtained by counting the number of particle dropout marks contained in a region of 270 μm × 200 μm in a scanning electron microscope image having a magnification of 500 times, and averaging the number of particle dropout marks in 25 regions. The value is set. The number of particles is a value obtained by counting the number of protrusions derived from the organic polymer fine particles contained in the same region as the region where the number of particle dropout marks was measured, and similarly averaging the number of particles in 25 regions. And.

The particle dropout marks of the organic polymer fine particles and the protrusions derived from the organic polymer fine particles are distinguishable as shown in FIG.

The drop-off rate from the fine particle-containing resin film immediately after molding is preferably 3% or less, more preferably 2.5% or less, still more preferably 1.5% or less.

Furthermore, by using the organic polymer fine particles of the present invention, the particles are suppressed from falling off from the fine particle-containing resin film even after the fine particle-containing resin film is rubbed. For example, the dropout rate after the following friction test is preferably 10% or less, more preferably 8% or less, still more preferably 6% or less.

[Friction test]
The fine particle-containing resin films come into contact with each other on a measuring table in which the fine particle-containing resin film is fixed to a weight having a bottom width of 63.5 mm, a bottom length of 63.5 mm, and a weight of 200 g, and the fine particle-containing resin film is fixed on the upper surface. Place a weight on which the fine particle-containing resin film is fixed. Then, the weight is slid in the same direction at a speed of 150 mm / min. The area where the weight is slid 20 times is defined as the measurement area.

If there is a difference in the degree of crystal growth on both sides of the fine particle-containing resin film and the smoothness is different, a surface with less crystal growth (smoother) is used for the friction test.

Further, the static friction coefficient _μs of the fine particle-containing resin film is preferably 0.5 or less, more preferably 0.3 or less, still more preferably 0.2 or less, and preferably 0.01 or more.

The dynamic friction coefficient μ _k of the fine particle-containing resin film is preferably 0.3 or less, more preferably 0.2 or less, still more preferably 0.15 or less, and preferably 0.01 or more.

The thickness of the fine particle-containing resin film is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 0.7 μm or more, preferably 1 mm or less, more preferably 500 μm or less, still more preferably 400 μm or less. be.

The ratio of the mass average particle diameter of the organic polymer fine particles to the thickness of the fine particle-containing resin film (organic polymer fine particle diameter / fine particle-containing resin film thickness) is preferably 1 or more, more preferably 1.5 or more. It is more preferably 2 or more, preferably 10 or less, more preferably 7 or less, still more preferably 6 or less.

The fine particle-containing resin film may be further laminated with the base film. As described above, a laminated film including at least one layer of the fine particle-containing resin film and the base film is also included in the technical scope of the present invention. It is preferable that at least one layer of the fine particle-containing resin film is laminated on the base film, and more preferably two layers of the fine particle-containing resin film are laminated on the base film. Further, it may be laminated on both sides or one side of the base film, and it is preferable to laminate it on both sides of the base film. Hereinafter, when the fine particle-containing resin film and the base film are laminated, the fine particle-containing resin film may be referred to as a “fine particle-added skin layer” and the base film may be referred to as a “core layer”.

The resin used for the core layer (base film) is selected from the range exemplified as the resin used for the masterbatch. Further, the resin used for the core layer (base film) may be the same as or different from the resin used for the fine particle-containing resin film, and is preferably the same. The core layer (base film) may or may not contain the organic polymer fine particles.

In the laminated film, the ratio of the thickness of the core layer to the thickness of the fine particle-added skin layer (core layer thickness / fine particle-added skin layer thickness) is preferably 2 or more, more preferably 10 or more, still more preferably 15 or more, and is preferable. Is 50 or less, more preferably 30 or less, still more preferably 20 or less.

The organic polymer fine particles contained in the laminated film are preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and preferably 5% by mass or more. Hereinafter, it is more preferably 2% by mass or less, still more preferably 1% by mass or less.

The thickness of the laminated film in which the fine particle-added skin layer and the core layer are laminated is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, preferably 1 mm or less, more preferably 500 μm or less, still more preferably 400 μm. It is as follows.

When producing the fine particle-containing resin film, the organic polymer fine particles are directly or processed into the masterbatch and then mixed with the resin (preferably melt-mixed) so as to have the above ratio to obtain a resin composition. By molding this resin composition, a fine particle-containing resin film can be produced. When molding the resin composition, it is preferable to melt-extrude the resin composition, and it is preferable to further stretch the resin composition. An unstretched film (cast film) can be obtained by melt extrusion, and a stretched film can be produced by stretching this unstretched film (cast film).

The resin composition for producing the fine particle-containing resin film is also included in the technical scope of the present invention.

The masterbatch contains organic polymer fine particles in a high concentration, and by further mixing and diluting with a resin, a resin composition having a desired organic polymer fine particle concentration can be obtained. The resin used at this time may be the same as or different from the resin used for the masterbatch. In particular, from the viewpoint of productivity and processability, a polyolefin resin is preferable, a polypropylene resin is more preferable, and a unit derived from propylene is preferably 90% by mass or more, more preferably 95% by mass or more. It is a polypropylene resin of the above, and particularly preferably a homopolymer composed of only polypropylene. By using the masterbatch, it is possible to obtain a resin composition having good dispersibility of the organic polymer fine particles.

When a masterbatch is used, the resin used for dilution is preferably 2 parts by mass or more and 200 parts by mass or less, more preferably 3 parts by mass or more and 150 parts by mass or less, more preferably 150 parts by mass or less, based on 1 part by mass of the masterbatch. 5 parts by mass or more and 100 parts by mass or less.

As a method for molding the resin composition by mixing the organic polymer fine particles and the resin, a melt extrusion molding method such as a T-die method is preferable. When a laminated film is produced by laminating a fine particle-containing resin film and a base film, coextrusion may be performed. At this time, the melting temperature is preferably 180 to 240 ° C, more preferably 200 to 220 ° C.

The thickness of the unstretched film (cast film) is preferably 1 μm or more and 1 mm or less, for example. The thickness of the unstretched fine particle-containing resin film is preferably 1 μm or more and 900 μm or less, more preferably 10 μm or more and 700 μm or less, and further preferably 15 μm or more and 500 μm or less.

When the fine particle-containing resin film (fine particle-added skin layer) and the base film (core layer) are laminated, the thickness of the unstretched laminated film in which these are laminated is preferably 100 μm or more and 1 mm or less, more preferably 200 μm. As mentioned above, it is 500 μm or less, more preferably 250 μm or more and 400 μm or less.

Further, the stretch axis when stretching the unstretched film (cast film) may be uniaxial or biaxial, and biaxial is preferable. In the case of biaxial stretching, sequential biaxial stretching may be performed, or simultaneous biaxial stretching may be performed. The draw ratio is preferably 1 to 5 times on both the vertical axis and the horizontal axis, and more preferably 2 to 4 times.

Further, the thickness of the fine particle-containing resin film after stretching is, for example, preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 0.7 μm or more, preferably 50 μm or less, more preferably 20 μm or less. It is more preferably 10 μm or less, still more preferably 5 μm or less, and particularly preferably 3 μm or less.

When the fine particle-containing resin film (fine particle-added skin layer) and the base film (core layer) are laminated, the thickness of the laminated film after stretching the laminated film is preferably 5 μm or more, more preferably 10 μm or more. It is more preferably 15 μm or more, preferably 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less.

The organic polymer fine particles of the present invention can suppress an increase in frictional resistance even when the films are repeatedly rubbed against each other. Therefore, it is useful as an anti-blocking agent for resin films. Further, the resin film containing the organic polymer fine particles of the present invention is suitably used as a general packaging material, a food packaging material such as a food packaging film, or a pharmaceutical packaging material such as a pharmaceutical packaging film.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples as well as the present invention, and appropriate modifications are made to the extent that it can meet the purposes of the preceding and the following. Of course, it is possible to carry out, and all of them are included in the technical scope of the present invention.
In the following, unless otherwise specified, "part" means "part by mass" and "%" means "% by mass".

Al content Al was quantified by radio frequency inductively coupled plasma (ICP) emission spectroscopy.
0.5 g ± 0.05 g of the organic polymer fine particles to be measured were placed in a platinum crucible and heated on a hot plate for carbonization. The platinum crucible and the magnetic crucible were placed in a magnetic crucible and heated to 700 ° C. in an electric furnace for incineration. Nitric acid was added to a platinum crucible taken out from an electric furnace, and the residue was dissolved while heating, and the solution was made up to 20 ml with ultrapure water. For blanks, the same work was done with an empty platinum crucible. The sample solution was appropriately diluted, and Al was quantified with a high-frequency inductively coupled plasma emission spectrometer: iCAP 6500 DU0 (manufactured by Thermo Fisher Scientific).
The limit of quantification of Al by the above apparatus was 2.67 ppb, and the amount of Al in the blank was 15 ppb.

Sulfur atom content Sulfur atom quantification was measured by high frequency inductively coupled plasma (ICP) emission spectroscopy.
0.5 g ± 0.05 g of the organic polymer fine particles to be measured were placed in a platinum crucible and heated on a hot plate for carbonization. The platinum crucible and the magnetic crucible were placed in a magnetic crucible and heated to 700 ° C. in an electric furnace for incineration. Nitric acid was added to a platinum crucible taken out from an electric furnace, and the residue was dissolved while heating, and the solution was made up to 20 mL with ultrapure water. For blanks, the same work was done with an empty platinum crucible. The sample solution was appropriately diluted, and S was quantified with a high-frequency inductively coupled plasma emission spectrometer: iCAP 6500 DU0 (manufactured by Thermo Fisher Scientific).
The limit of sulfur quantification by the above apparatus was 4.05 ppb, and the amount of sulfur in the blank was 30 ppb.

Average particle size / variation coefficient 0.1 g of organic polymer fine particles was dispersed in 0.5 g of a surfactant (“Neoperex (registered trademark) G15”, sodium dodecylbenzene sulfonic acid salt, manufactured by Kao Co., Ltd.). Next, after adding 15 g of deionized water to the dispersed viscous liquid, ultrasonic waves were applied to prepare an organic polymer fine particle dispersion liquid in which particles were dispersed, and a precision particle size distribution measuring device (manufactured by Beckman Coulter). The particle size of 30,000 particles was measured using "Coulter Multisizer Type III", aperture 50 μm), and the average particle size based on the mass and the fluctuation coefficient of the particle size were obtained.
Coefficient of variation of particle size (%) = (σ / d) × 100
Here, σ is the standard deviation of the particle size, and d is the average particle size based on the mass.

Thermal decomposition start temperature The thermal decomposition start temperature of the organic polymer fine particles is a sample amount of 15 mg and a temperature rise rate of 10 ° C./min (maximum reached temperature) using a thermal analyzer (DTG-50M, manufactured by Shimadzu Corporation). It was measured under the conditions of 500 ° C.), air, and a flow rate of 20 mL / min. First, using a precision balance, weigh a 15 mg sample in a specified aluminum cup, set this aluminum cup in the specified position of the thermal analyzer, and adjust the air to flow at the specified flow rate (20 mL / min). After the device became stable, the temperature rise was started. The intersection of the extension of the baseline (horizontal line portion) of the TG curve obtained at this time and the tangent line of the mass reduction portion (diagonal portion falling to the right) was defined as the thermal decomposition start temperature of the organic polymer fine particles.

Hydrophobicity test Prepare a glass container with a cross-sectional area of 5 cm ² or more and 10 cm ² or less filled with 20 mL of deionized water at a liquid temperature of 20 ° C., and gently pour 0.02 ± 0.005 g of organic polymer fine particles on the water surface. The time until the first particle started to settle was defined as the settling start time.

Measurement of moisture content Karl Fischer volume titration method automatic moisture measuring device KF-07 type (manufactured by Mitsubishi Chemical Corporation) was used to measure the moisture content of the particles. Aquamicron SS-Z 3 mg (manufactured by Mitsubishi Chemical Corporation) was used as the titrator, and the titration test of the titrator was performed using deionized water. About 0.1 g of sufficiently pulverized dry pulverized particles were measured using the above titrator while being dispersed in a methanol solution.
As the dry pulverized particles to be measured, organic polymer fine particles having a water content of 1% or less are pulverized using a Super Jet Mill SJ-500 (manufactured by Nisshin Engineering Co., Ltd.) at room temperature at a pulverization pressure of 0.3 MPa. I made it. The average particle size based on the mass of the obtained dried pulverized particles is within ± 0.2 μm from the measured value of the organic polymer fine particles in the polymer solution after the completion of polymerization, and the fluctuation coefficient is in the polymer solution. It was within ± 2.5% from the organic polymer fine particles of.

Measurement of Friction Coefficient The friction coefficient was measured using the biaxially stretched films (BOPP) obtained in Examples 1 to 4 and Comparative Examples 1 to 3. When a film molded from a T-die extruder (manufactured by Soken Co., Ltd.) is wound to produce a cast film, the cooling rate is different on the side that comes into contact with the take-up roll and the opposite side (called the air surface). different. Generally, on the roll surface side, crystal growth is suppressed because the cooling rate is faster, the roll surface side of the finished cast film is smooth, and large crystal growth is seen on the air surface side, and the roll surface side and the roll surface side. The surface becomes uneven in comparison. In the measurement of the coefficient of friction, the roll surface side was the measurement target.

An Autograph AG-X manufactured by Shimadzu Corporation was used as a friction coefficient measuring device. As a jig for measuring the coefficient of friction, a load cell capacity of 50 N, a dedicated coefficient of friction measuring table (width 200 mm x length 355 mm), a moving weight (dimensions width 63.5 mm x length 63.5 mm x thickness 6.4 mm, mass) 200 g) was used.

The 12 cm × 12 cm area and the 12 cm × 18 cm area in the center of the film were used for the measurement. That is, one sample of 12 cm × 18 cm and one sample of 12 cm × 12 cm were cut from the center of the film. Then, a sample of 12 cm × 18 cm was fixed to the measuring table with the roll surface side to be the frictional resistance measuring surface facing up, and the four corners of the sample were fastened with cellophane tape. Further, in a sample of 12 cm × 12 cm, a moving weight was wrapped so that the roll surface side was on the outside, and fixed with cellophane tape.

A moving weight wrapped with a sample was connected to a crosshead, slid on a film attached to a measuring table at a speed of 150 mm / min, running resistance was measured, and the following static friction coefficient and dynamic friction coefficient were determined.
Static friction coefficient (μ _s ) = maximum tensile test force at start of moving weight / (moving weight mass x gravitational acceleration)
Dynamic friction coefficient (μ _k ) = average tensile test force during moving weight running / (moving weight mass x gravitational acceleration)
The mileage was 100 mm, and the distance for obtaining the dynamic friction coefficient was 30 mm to 90 mm from the starting point of the mileage.
The friction coefficient was measured 20 times in succession, and the friction coefficient was obtained by averaging the measured values from the first to the fourth times.
The rate of increase in the coefficient of friction was calculated as follows.
Dynamic friction coefficient increase rate (%) = (20th dynamic friction coefficient-1st dynamic friction coefficient) / 1st dynamic friction coefficient A film sample after measuring the running resistance 20 times is used for counting the number of drops below. And said.

Counting the number of drops by SEM measurement After the friction test, the surface of the obtained film sample was observed using an SEM (scanning electron microscope) VK-8500 (manufactured by KEYENCE CORPORATION) at an acceleration voltage of 5 kV (secondary electron image). Was done.

For each film sample, 25 images of a region of 270 μm × 200 μm were taken with a 500x field of view. The number of particles (the number of protrusions derived from the organic polymer fine particles) and the number of drops (particle drop marks) contained in each photographed image were counted, and the number of drops was calculated based on the following formula.
Dropout rate (%) = Dropout number / (particle number + dropout number)
In the SEM image, as shown in FIG. 1, the traces of the dropped particles can be clearly observed, so that the number of dropped particles can be easily counted.

Quantification of Hindered Phenolic Antioxidant (Irganox® 1010) Quantification of Irganox® 1010 was performed using high performance liquid chromatography (HPLC). The measurement conditions are as shown below.

Column: CAPCELL PAK C18 TYPE manufactured by Shiseido Co., Ltd.
MG 5 μm Size 4.6 mm I. D. × 250 mm
Column temperature: 40 ° C
Eluent: Methanol / acetonitrile = 50/50
Detector: UV 280nm
Flow rate: 1 mL / min

Sample preparation, sample measurement, and calculation of antioxidant concentration are as shown below.
(1) Sample Preparation-Irganox® 1010 Standard Sample An acetonitrile solution of Irganox® 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was prepared. Several points were selected in the range of concentration of about 10 to 100 ppm.
-Sample of fine particles of organic polymer 1 g of fine particles of organic polymer were dispersed in 10 mL of chloroform, and the mixture was stirred at room temperature for 1 day. The stirred dispersion was filtered through a filter having a pore size of 0.45 μm or less, and the filtrate was collected. The filtrate was concentrated and diluted with acetonitrile to prepare a sample solution.
(2) Sample measurement Irganox (registered trademark) 1010 standard sample and organic polymer fine particle sample were measured at room temperature. A calibration curve was prepared according to the measurement results of Irganox® 1010 standard sample (peak position about 8.4 to 8.5 min). Using this calibration curve, Irganox® 1010 contained in the organic polymer fine particle sample was quantified.

Example 1
Preparation of organic polymer fine particles In a flask equipped with a stirrer, an inert gas introduction tube, a reflux condenser and a thermometer, a polyoxyethylene distyrylphenyl ether sulfate ammonium salt (trade name "HITENOL (registered trademark) NF-08") , Daiichi Kogyo Seiyaku Co., Ltd.) 523 parts of deionized water in which 3.6 parts were dissolved was charged. 252 parts of methyl methacrylate (MMA) as a monomer, 108 parts of ethylene glycol dimethacrylate (EGDMA), and 3.6 parts of lauryl peroxide (LPO) as a polymerization initiator prepared in advance there (to the monomer mass). 1% by mass), and a hindered phenolic antioxidant as an antioxidant (manufactured by BASF Japan, trade name "Irganox® 1010", pentaerythritol tetrakis [3- (3,5-di-tert-). Butyl-4-hydroxyphenyl) propionate]) 1.8 parts (0.5% by mass with respect to the monomer) was charged, and T.I. K. Using Homomixer MARK II model 2.5 (manufactured by Primix Corporation), the suspension was stirred at 5000 rpm for 10 minutes to obtain a uniform suspension.

Add 900 parts of deionized water to the suspension, then heat the reaction solution to 65 ° C while blowing nitrogen gas, keep the reaction vessel warm at 65 ° C, and the liquid temperature reaches 75 ° C by self-heating. The reaction was started at this point, and stirring was continued at this temperature for 1.5 hours, and then the temperature of the polymerization solution was further raised to 85 ° C. and the mixture was stirred for 2 hours to complete the polymerization reaction. Then, the reaction solution (suspension) was cooled to 50 ° C. or lower, allowed to pass, and the polymerization product was collected by filtration. This was dried at 80 ° C. for 15 hours or more using a hot air dryer (manufactured by Yamato Kagaku Co., Ltd.) to obtain organic polymer fine particles. The water content of the organic polymer fine particles was 1% or less.

Since the obtained dried organic polymer fine particles were aggregated by drying, they were pulverized using a super jet mill SJ-500 (manufactured by Nisshin Engineering Co., Ltd.) at room temperature at a pulverization pressure of 0.3 MPa. As a result, organic polymer fine particles without aggregation were obtained.

Preparation of film Further, 10 parts of the obtained organic polymer fine particles, 90 parts of polypropylene pellets (Novatec (registered trademark) FY4 manufactured by Japan Polypropylene Corporation), and 0.5 parts of Irganox (registered trademark) as an antioxidant. , And 168 0.5 parts of Irgafos (registered trademark) were mixed using a co-rotating twin-screw kneading extruder ((HK-25D) manufactured by Parker Corporation) and melt-kneaded at 212 ° C. Water-cooled to obtain strands. By appropriately cutting, a polypropylene masterbatch containing 10% of organic polymer fine particles was prepared.

Using the obtained polypropylene masterbatch and polypropylene pellets, a cast film of 2 types and 3 layers was prepared. A structure was adopted in which fine particle-added skin layers were laminated on both sides of the core layer. A T-die extruder (manufactured by Soken Co., Ltd.) was used to prepare the film. For the two fine particle-added skin layers, 1 part of a masterbatch containing 10% organic polymer fine particles and 9 parts of polypropylene pellets were used, and 180 parts of polypropylene pellets alone were used for the core layer. The thickness of the cast film was 16 μm for the skin layer to which fine particles were added and 288 μm for the core layer, and a cast film having a total thickness of 320 μm was obtained.

The obtained cast film was cut into a length x width = 9 x 9 cm, and the stretching ratio was set to 3 times in length and 3 times in width under heating conditions of 165 ° C with a simultaneous biaxial stretching machine (manufactured by Toyo Seiki Co., Ltd.). Simultaneous biaxial stretching was performed. The size of the obtained film was 22 cm × 22 cm. The thickness of the central portion of the stretched film was about 20 μm on average, but the thickness of the edge portion of the film was about 100 μm, and the thickness of the central portion 12 cm × 12 to 18 cm was mainly about 20 μm.

The film formed from the T-die extruder (manufactured by Soken Co., Ltd.) is obtained by winding when producing a cast film, and the side that comes into contact with the take-up roll is called the roll surface, and vice versa. The surface is called the air surface. Generally, crystal growth is suppressed on the roll surface side because the cooling rate is faster, and the roll surface side of the finished cast film is smooth and large crystal growth is seen on the air surface side, and the roll surface side and the roll surface side. The surface becomes uneven in comparison.

Examples 2-4
Organic polymer fine particles were produced in the same manner as in Example 1 except that the raw material composition was changed to be as shown in Table 1. The water content of the organic polymer fine particles after drying was 1% or less. Further, a film was produced in the same manner as in Example 1.

Average particle size, coefficient of variation, average particle size ratio (Dn / Dw), settling start time, thermal decomposition start temperature, friction coefficient of film (μ _s , μ _k ), before and after friction test of the obtained organic polymer fine particles Table 2 shows the film dropout rate.

Moreover, when the Al content of the organic polymer fine particles obtained in Example 3 was measured, it was less than 30 ppb.

Comparative Examples 1 to 3
The polymerization reaction was completed in the same manner as in Example 1 except that the raw material composition was changed to be as shown in Table 1. Then, the reaction solution (suspension) was cooled from 70 ° C. to 80 ° C., 25 parts of a 0.6% aluminum sulfate aqueous solution was added, and the mixture was stirred for 30 minutes or more. After that, the reaction solution obtained by cooling to 50 ° C. or lower is filtered, the polymerization product is collected by filtration, and this is dried at 80 ° C. for 15 hours or more with a hot air dryer (manufactured by Yamato Kagaku Co., Ltd.). To obtain organic polymer fine particles.

Since the obtained dried organic polymer fine particles were aggregated by drying, they were pulverized using a super jet mill SJ-500 (manufactured by Nisshin Engineering Co., Ltd.) at room temperature at a pulverization pressure of 0.3 MPa. As a result, organic polymer fine particles without aggregation were obtained. Further, a film was produced in the same manner as in Example 1.

Moreover, when the Al content of the obtained organic polymer fine particles was measured, it was 42.3 ppm in the organic polymer fine particles of Comparative Example 1.

Average particle size, coefficient of variation, average particle size ratio (Dn / Dw), settling start time, thermal decomposition start temperature, friction coefficient of film (μ _s , μ _k ), before and after friction test of the obtained organic polymer fine particles Table 2 shows the film dropout rate.

In the table, "MMA" is methyl methacrylate,
"EGDMA" is ethylene glycol dimethacrylate,
"1.6HX" is 1,6-hexanediol dimethacrylate,
"TMPTMA" is trimethylolpropane trimethacrylate,
"LPO" is lauroyl peroxide,
"Irganox 1010" is pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate],
Shall mean each.

By using the organic polymer fine particles of the present invention, it is possible to suppress an increase in frictional resistance between the films even if the films are repeatedly rubbed against each other. Therefore, the organic polymer fine particles of the present invention are useful as an anti-blocking agent for resin films. Further, the resin film containing the organic polymer fine particles of the present invention is suitably used as a general packaging material, a food packaging material such as a food packaging film, or a pharmaceutical packaging material such as a pharmaceutical packaging film.

Claims (6)

A (meth) acrylic polymer crosslinked with a crosslinkable monomer,
The structural unit based on the crosslinkable monomer is 5% by mass or more and 40% by mass or less.
The following sedimentation start time is 10 seconds or more,
The Al content measured by radio frequency inductively coupled plasma (ICP) emission spectroscopy is 1 ppm or less.
Contains 0.2% by mass or more of hindered phenolic antioxidants or components derived from them.
The hindered phenolic antioxidants are pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-). 1-Hydroxyphenyl) propionate, N, N'-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide], benzenepropanoic acid, 3,5 -Bis (1,1-dimethylethyl) -4-hydroxy, C7-C9 side chain alkyl ester, 3,3', 3 ", 5,5', 5" -hexa-tert-butyl-a, a', a "-(Mesitylen-2,4,6-tolyl) tri-p-cresol, hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], diethyl [[3, 5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, 2,4-dimethyl-6- (1-methylpentadecyl) phenol, or 2', 3-bis [3- (3) , 5-Di-tert-butyl-4-hydroxyphenyl) propionyl] Organic polymer fine particles that are propionohydrazide and have a compression deformation recovery rate of 6% or more.
[Settling start time]
Prepare a glass container with a cross-sectional area of 5 cm ² or more and 10 cm ² or less filled with 20 mL of deionized water at a liquid temperature of 20 ° C., and gently float 0.02 ± 0.005 g of organic polymer fine particles on the water surface. The time until the first particle starts to settle is defined as the settling start time. The organic polymer fine particles according to claim 1, wherein the mass average particle diameter is 1.0 μm or more and 15 μm or less. The organic polymer fine particles according to claim 1 or 2, which are used as an anti-blocking agent for a film. A masterbatch containing the organic polymer fine particles according to any one of claims 1 to 3 and a resin. A resin film containing the organic polymer fine particles according to any one of claims 1 to 3 and a resin. A laminated film containing at least one layer of the resin film according to claim 5 and a base film.

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