JP7542964B2 - Method for producing organic particles, organic particles, composition, coating film, and laminate - Google Patents

Description

The present invention relates to a method for producing organic particles, organic particles, a composition, a coating film, and a laminate.

In recent years, there has been a demand for organic particles with high hydrophilicity as a material for use in various hard coat films, etc. Highly hydrophilic organic particles can exhibit high dispersibility when mixed with the main hard coat agent, etc., and are expected to significantly improve various physical properties of hard coat films, etc. Therefore, there is a demand for the development of hydrophilic organic particle technology suitable for various applications.

On the other hand, plasma treatment is used as a method for surface treatment of inorganic particles. For example, Patent Document 1 discloses an atmospheric pressure plasma treatment method characterized in that a plasma generating electrode is placed in a sealed container having a gas inlet and outlet, a container made of a dielectric material is placed on one side of the electrode, ultrafine particles are filled in the container, the sealed container is made into an atmospheric pressure plasma generating atmosphere, and atmospheric pressure plasma is generated between the two electrodes to treat the surface of the fine particles.

Japanese Patent Application Publication No. 06-134296

However, there is still room for improvement in the technology for making organic particles hydrophilic. For example, modifiers such as surfactants are added to impart hydrophilicity, but this creates problems with the removal of residual substances and contamination. For this reason, a different method of making organic particles hydrophilic is needed. In addition, even if organic particles are made hydrophilic by conventional methods, there is a problem that the effect is difficult to maintain for more than 30 days due to the deterioration of hydrophilicity over time.

On the other hand, while conventional plasma treatments such as those described in Patent Document 1 are non-contact treatment technologies, they are limited to surface treatment of inorganic particles such as titanium oxide and aluminum oxide, and the reality is that sufficient consideration has not been given to their application to organic particles.

The present invention has been made in view of the above circumstances, and has as its main object to provide a method for producing organic particles, organic particles, a composition, a coating film, and a laminate that can make particles hydrophilic and maintain the hydrophilicity for a long period of time.

The inventors conducted extensive research to achieve the above-mentioned objectives and have now completed the present invention.

In other words, the present invention is as follows.

(1)
A method for producing organic particles, comprising a step of irradiating organic particles with atmospheric pressure plasma while exposing the organic particles to a hydrophilic gas and an inert gas in a reaction vessel.
(2)
The method for producing organic particles according to (1), wherein when a water droplet is dropped onto a film consisting only of the organic particles, the water droplet area expansion rate is defined as the ratio of the area of the water droplet viewed from above two minutes after the dropping to the area of the water droplet viewed from above immediately after the dropping, and the water droplet area expansion rate immediately after the film consisting only of the organic particles is 1.1 times or more.
(3)
The method for producing organic particles according to (2), wherein a ratio of the water droplet area expansion rate immediately after the film consisting of only the organic particles is formed to the water droplet area expansion rate 30 days after the film is formed is 0.9 or more.
(4)
The method for producing organic particles according to any one of (1) to (3), wherein the hydrophilic gas is a compound containing a hydroxyl group and/or an amino group.
(5)
The method for producing organic particles according to any one of (1) to (4), wherein the inert gas is brought into contact with a solution containing the hydrophilic gas before the inert gas is supplied to the reaction vessel.
(6)
Organic particles, in which when a water droplet is dropped onto a film consisting only of organic particles, the water droplet area expansion rate is the ratio of the area of the water droplet viewed from above immediately after the dropping to the area of the water droplet viewed from above 2 minutes after the dropping, and the water droplet area expansion rate immediately after the film consisting only of the organic particles is 1.1 times or more.
(7)
The organic particles according to (6), wherein the ratio of the water droplet area expansion rate immediately after the film consisting of only the organic particles is formed to the water droplet area expansion rate 30 days after the film is formed is 0.9 or more.
(8)
The organic particles according to (6) or (7), wherein the organic particles are surface-treated by atmospheric pressure plasma exposure.
(9)
A composition comprising organic particles according to any one of (6) to (8), a resin different from the organic particles, and a curing agent.
(10)
A coating film containing organic particles according to any one of (6) to (8).
(11)
A laminate comprising a substrate and a functional layer formed on at least a portion of a surface of the substrate, the functional layer comprising organic particles according to any one of (6) to (8).

The present invention provides a method for producing organic particles, organic particles, a composition, a coating film, and a laminate that can make particles hydrophilic and maintain the hydrophilicity for a long period of time.

1A to 1C are schematic diagrams for explaining an example of a plasma treatment in the present embodiment. 10A to 10C are schematic diagrams for explaining another example of the plasma treatment in the present embodiment. FIG. 2 is a conceptual diagram for explaining measurement of a water drop area expansion rate. FIG. 2 is a cross-sectional view of an example of a laminate according to the present embodiment.

The following describes in detail the form for carrying out the present invention (hereinafter, simply referred to as the "present embodiment"). The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out with appropriate modifications within the scope of its gist.

In this specification, terms with "abbreviation" attached indicate the meaning of the term excluding "abbreviation" within the scope of common technical knowledge of a person skilled in the art, and also include the meaning itself excluding "abbreviation." Furthermore, unless otherwise specified, "(meth)acrylic" includes methacrylic and acrylic, and "(meth)acrylate" includes methacrylate and acrylate. Furthermore, "film" and "sheet" may be collectively referred to as "film."

(Manufacturing method)

The manufacturing method according to this embodiment includes a step of irradiating organic particles with atmospheric plasma in a reaction vessel while exposing the organic particles to a hydrophilic gas and an inert gas. By carrying out this step, it is possible to impart hydrophilicity to the organic particles (to make them hydrophilic). Furthermore, the hydrophilicity of the organic particles is maintained at a high level for a long period of time, such as 30 days or more. Although the reason for this is unclear, it is presumed that the use of a hydrophilic gas during atmospheric plasma irradiation effectively introduces hydrophilic groups (e.g., hydroxyl groups, amino groups, etc.) of the hydrophilic gas to the particle surfaces of the organic particles (however, the effects according to this embodiment are not limited to these).

And because atmospheric pressure plasma allows for continuous plasma irradiation, it can be irradiated directly onto the target organic particles. And atmospheric pressure plasma can form higher density plasma than low pressure plasma. On the other hand, because atmospheric pressure plasma is not a vacuum system, it is a simple method with less restrictions on device configuration and condition settings.

Conventionally, modifiers such as surfactants have been added to make organic particles such as resins and carbon hydrophilic, but this has problems such as the need to remove residual substances and the occurrence of contamination. However, the atmospheric pressure plasma treatment performed in the manufacturing method according to this embodiment is a non-contact treatment, and therefore such problems can be avoided.

The device for performing atmospheric pressure plasma irradiation (atmospheric pressure plasma irradiation device) may be any device capable of performing atmospheric pressure plasma irradiation. For example, the following method may be adopted.

Figure 1 is a schematic diagram illustrating an example of plasma processing in this embodiment.

In the atmospheric pressure plasma irradiation device 10, the organic particles 20 arranged therein are exposed to the inert gas 30 and the hydrophilic gas 40 while being irradiated with the plasma P under atmospheric pressure conditions. The inert gas 30 is supplied from the inert gas supply unit 32 into the reaction vessel of the atmospheric pressure plasma irradiation device 10, and the hydrophilic gas 40 is supplied from the hydrophilic gas supply unit 42 into the reaction vessel, and each is exposed to the organic particles 20. Then, atmospheric pressure plasma irradiation is performed. The exhaust gas 50 is then exhausted to the outside from the exhaust unit 52.

The atmospheric plasma irradiation device 10 is preferably a drum type. In the case of a drum type, the organic particles 20 are rotated and oscillated in the treatment container, which prevents the particles from agglomerating and enables uniform hydrophilization of the particle surfaces. In addition, in this embodiment, treatment can be performed without using flammable gases such as oxygen, so there is no risk of ignition or fire, and it is very safe.

The type of organic particles 20 is not particularly limited as long as it is an organic material. Examples of organic particles 20 include resins, carbon (carbon black, etc.), and natural materials (e.g., wood, cellulose, etc.). Among these, resins and carbon are preferred.

The resin is not particularly limited, but examples include (meth)acrylic resins, styrene resins, olefin resins, polycarbonates, silicones, etc.

Examples of (meth)acrylic resins include those containing (meth)acrylic acid and/or (meth)acrylic acid alkyl esters as structural units. In the (meth)acrylic resin, (meth)acrylic acid and (meth)acrylic acid alkyl esters preferably account for 50 mol % or more of all structural units, and (meth)acrylic acid or (meth)acrylic acid alkyl esters are more preferably 50 mol % or more of all structural units.

Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate.

The (meth)acrylic resin may contain other structural units in addition to (meth)acrylic acid and (meth)acrylic acid alkyl ester. Examples include acrylonitrile, methacrylonitrile, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)-methylacrylate maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

Examples of styrene-based resins include those that contain polystyrene as a constituent unit. Polystyrene-based resins may contain other constituent units besides polystyrene. Examples include acrylonitrile and butadiene. Examples include styrene-acrylonitrile copolymer resin (AS resin), styrene-butadiene-acrylonitrile copolymer resin (ABS resin), etc.

Examples of olefin-based resins include polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), and olefin-based elastomers.

Examples of silicones include silicone rubber and polyorganosilsesquioxane.

Examples of carbon include carbon black. Examples of carbon black include furnace black, acetylene black, channel black, thermal black, etc. In addition, either soft carbon or hard carbon may be used.

The organic particles 20 preferably have an average particle size of 0.01 to 100 μm. The average particle size refers to the _D50 value of the particle size distribution measured by a laser diffraction/scattering method.

The organic particles 20 preferably have a weight average molecular weight of 10,000 to 1,000,000. The weight average molecular weight refers to the weight average molecular weight (M _w ) calculated in terms of polystyrene, obtained by gel permeation chromatography (GPC) analysis.

The type of inert gas 30 is not particularly limited, and any known inert gas can be used. Specific examples of the inert gas 30 include helium, argon, and nitrogen. Among these, rare gases such as helium and argon, which are highly stable, are preferred. Furthermore, these inert gases 30 may be used alone or in combination of two or more types.

The flow rate of the inert gas 30 is not particularly limited, and suitable conditions can be set as appropriate taking into consideration the application, purpose, etc. Usually, the flow rate of the inert gas 30 is preferably 1 to 4 L/min. The lower limit of this flow rate is more preferably 1.5 L/min or more, and even more preferably 1.8 L/min or more. The upper limit of this flow rate is more preferably 3 L/min or less, and even more preferably 2.5 L/min or less.

The type of hydrophilic gas 40 is not particularly limited, and any known gas may be used. From the viewpoint of hydrophilizing the organic particles 20, the hydrophilic gas 40 is preferably a compound containing a hydroxyl group and/or an amino group. Compounds having an amino group are preferably ammonia, amine compounds, etc.

The compound having a hydroxyl group is preferably an alcohol. Examples of the alcohol include monoalcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, and phenethyl alcohol; diols such as ethylene glycol, propylene glycol, and butanediol; triols such as triethylene glycol; and polyols such as polyethylene glycol. Among these, monoalcohols are more preferred from the viewpoints of ease of vaporization and hydrophilicity effects, and methanol, ethanol, isopropanol, and the like are even more preferred.

Examples of compounds having an amino group include ammonia, methylamine, diethylamine, etc. Among these, ammonia is preferred from the viewpoints of ease of vaporization and hydrophilicity.

The hydrophilic gas 40 may be one of the above-mentioned gases, or two or more of them may be used in combination. From the viewpoint of preventing ignition and fire, it is preferable that the hydrophilic gas is a non-flammable gas.

Normally, the flow rate of the hydrophilic gas 40 is preferably 1 to 100 mL/min. The lower limit of this flow rate is more preferably 1.5 mL/min or more, and even more preferably 1.8 mL/min or more. The upper limit of this flow rate is more preferably 50 mL/min or less, and even more preferably 30 mL/min or less.

There are no particular limitations on the conditions for atmospheric pressure plasma irradiation, and suitable conditions can be set as appropriate taking into consideration the application, purpose, etc. The plasma output is usually 40 W to 3 kW. The lower limit of the plasma output is preferably 50 W or more, and more preferably 60 W or more. The upper limit of the plasma output is preferably 1 kW or less, more preferably 200 W or less, and even more preferably 100 W or less.

The plasma irradiation time is usually 5 minutes to 5 hours. The lower limit of the irradiation time is preferably 30 minutes or more, and more preferably 1 hour or more. The upper limit of the irradiation time is preferably 4 hours or less, and more preferably 3.5 hours or less.

In addition, in the manufacturing method according to this embodiment, it is preferable to bring the inert gas 30 into contact with a solution containing the hydrophilic gas 40 before supplying the inert gas 30 to the reaction vessel. This can further improve the hydrophilicity effect. This is explained below.

Figure 2 is a schematic diagram illustrating another example of plasma processing in this embodiment.

In the embodiment shown in FIG. 1, the inert gas 30 and the hydrophilic gas 40 are directly applied to the organic particles 20 in the reaction vessel, whereas in the embodiment shown in FIG. 2, the hydrophilic gas 40 and the inert gas 30 are applied to the organic particles 20 by contacting the inert gas 30 with a solution containing the hydrophilic gas 40.

The inert gas 30 is sent to a hydrophilic solution tank 60 in which a solution (hydrophilic solution) containing the hydrophilic gas 40 is stored, and aerates the hydrophilic solution. In this case, the inert gas 30 is preferably bubbled in a container containing the hydrophilic gas 40. This allows the inert gas to be introduced into the reaction vessel together with the hydrophilic gas in a simple and efficient manner, further enhancing hydrophilicity.

The hydrophilic solution may be any solution containing hydrophilic gas 40, and is not particularly limited. Examples of the hydrophilic solution include a liquid of hydrophilic gas 40, and a solution containing hydrophilic gas 40 and a solvent. An example of the solvent is water (aqueous solution of hydrophilic gas 40). Suitable examples of the hydrophilic solution include the above-mentioned alcohol liquids such as methanol and ethanol; and an aqueous solution of ammonia (aqueous ammonia solution).

The inert gas 30 contacted with the hydrophilic solution becomes a mixed gas 70 containing the inert gas 30 and the hydrophilic gas 40, and is applied from the mixed gas supply unit 72 to the organic particles 20 in the atmospheric plasma irradiation device 10. Then, atmospheric plasma irradiation can be performed. In the atmospheric plasma irradiation, for example, the irradiation conditions described with reference to FIG. 1 can be used. Then, the exhaust gas 50 is discharged to the outside from the exhaust unit 52. The exhaust gas 50 may be introduced again into the hydrophilic solution tank 60 and applied as the mixed gas 70 from the mixed gas supply unit 72 to the organic particles 20 in the atmospheric plasma irradiation device 10. The gas flow rate when the mixed gas 70 is used is usually preferably 1 to 4 L/min. The lower limit of this flow rate is more preferably 1.5 L/min or more, and even more preferably 1.8 L/min or more. The upper limit of this flow rate is more preferably 3 L/min or less, and even more preferably 2.5 L/min or less.

(organic particles)

The organic particles obtained by the above-mentioned manufacturing method have high hydrophilicity and maintain a high level of hydrophilicity for a long period of time, such as 30 days or more. In a preferred example, the water droplet area drop ratio immediately after forming a film consisting of only organic particles is 1.1 times or more. In other words, the organic particles according to this embodiment are novel organic particles with such a water droplet area drop ratio of 1.1 times or more.

The water droplet area transmittance referred to here is the ratio of the area of the water droplet viewed from above two minutes after dropping onto a film consisting only of organic particles to the area of the water droplet viewed from above immediately after dropping. The water droplet area expansion rate is explained below.

Figure 3 is a conceptual diagram for explaining the measurement of water drop area expansion rate.

First, an organic particle layer is formed on a sample stage T to form a sample S. For example, a coating film can be used as the sample S. A drop of water is dropped onto the sample S. Then, the area A 0 of the water drop W immediately after dropping is calculated from the diameter d ₀ of the water drop W when viewed from above (i.e., FIG. 3). Then, two minutes after dropping, _{the area A f of} the water drop W two minutes after dropping is calculated from the diameter d _f of the water drop W when viewed from above in the same manner. Then, the water drop area expansion rate (D) is calculated based on the following formula (1).
D=A _f /A ₀ ...(1)

For example, if the area _A0 of the water droplet W immediately after the water droplet is dropped is 1 ^cm2 , and the area _Af of the water droplet W 2 minutes after the water droplet is dropped is 1.5 ^cm2 , the water droplet area expansion rate (D) is 1.5 times (= 1.5 ^cm2 ÷ 1.0 ^cm2 ). The larger the water droplet area expansion rate (D), the greater the wettability of the sample S (organic particles) with respect to water can be evaluated. Since the wettability with respect to water can be an index of the affinity of water with respect to the surface of the sample S (organic particles), high wettability can be evaluated as high hydrophilicity. Furthermore, if the attached water droplet W maintains a granular state, it can be said that the hydrophilicity is low.

Furthermore, the organic particles according to this embodiment are surface-treated by atmospheric pressure plasma exposure, and can exhibit hydrophilicity for a long period of time, such as 30 days or more. In a preferred example, the ratio of the water droplet area expansion rate immediately after forming a film made only of organic particles to the water droplet area expansion rate 30 days after the film is formed is 0.9 or more. This ratio can be calculated as follows.

First, immediately after forming a film from the organic particles, a first water drop area expansion ratio is determined based on the above-mentioned method for measuring the water drop area expansion ratio ( _D1 ). After that, the film is left to stand at room temperature and normal pressure for 30 days after the film formation. After 30 days, a second water drop area expansion ratio is determined based on the above-mentioned method for measuring the water drop area expansion ratio ( _D2 ). Then, the ratio ( _D2 / _D1 ) of the second water drop area expansion ratio to the first water drop area expansion ratio is determined.

For example, when the first water droplet area expansion rate (D ₁ ) is 1.5 times and the second water droplet area expansion rate (D ₂ ) is 1.2 times, the ratio (D ₂ /D ₁ ) is 0.8 (=1.2÷1.5). The closer this ratio is to 1, the slower the rate of decrease in hydrophilicity is, that is, the more hydrophilicity is maintained. In a preferred example of the organic particles according to this embodiment, this ratio can be set to 0.9 or more, and therefore high hydrophilicity can be maintained for a long period of time, such as 30 days or more.

(Composition)

This embodiment can be a composition containing the organic particles described above, a resin different from the organic particles, and a curing agent. The organic particles according to this embodiment have high hydrophilicity, and therefore have excellent dispersibility even in such a composition.

The resin different from the organic particles is a resin that has not been subjected to the atmospheric plasma treatment described above. Such a resin is not particularly limited, and known resins can be used. Specific examples thereof include epoxy resins. Examples of epoxy resins include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins; biphenyl-type epoxy resins; naphthalene ring-containing epoxy resins; alicyclic epoxy resins; dicyclopentadiene-type epoxy resins; phenol novolac-type epoxy resins; cresol novolac-type epoxy resins such as O-cresol novolac-type epoxy resins; triphenylmethane-type epoxy resins; and bromine-containing epoxy resins. Among these, bisphenol-type epoxy resins are preferred. Such different resins may be used alone or in combination of two or more.

The curing agent is not particularly limited, and any known agent can be used. Specific examples include acid anhydride curing agents such as hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and pyromellitic anhydride; amine curing agents such as diaminodiphenylmethane and metaphenylenediamine; and phenolic curing agents such as phenol novolac resin. Among these, acid anhydride curing agents and amine curing agents are preferred. Such curing agents may be used alone or in combination of two or more.

As a resin different from the organic particles, for example, an active energy ray curable resin can be used. Examples of active energy rays include ultraviolet rays, electron beams, and X-rays, but ultraviolet rays are preferable from the viewpoint of simplicity and use with inexpensive equipment. Specific examples of active energy ray curable resins include polyfunctional (meth)acrylic monomers and (meth)acrylate prepolymers.

Examples of polyfunctional (meth)acrylic monomers include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, propionic acid modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc.

Examples of (meth)acrylate-based prepolymers include polyester acrylate-based, epoxy acrylate-based, urethane acrylate-based, and polyol acrylate-based prepolymers.

These polyfunctional (meth)acrylate monomers and prepolymers may be used alone or in combination of two or more. In addition, when an active energy ray curable resin is used, a photopolymerization initiator may be used in combination.

Furthermore, if necessary, a solvent may be contained. The solvent is not particularly limited, and any known solvent may be used. Specific examples include organic solvents and water. Examples of organic solvents include the above-mentioned alcohols, acetone, ethyl acetate, acetic acid, tetrahydrofuran (THF), diethyl ether (DME), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), toluene, carbon tetrachloride, n-hexane, water, and mixtures thereof. As the solvent, a solvent that improves the dispersibility of the organic particles, different resins, and hardeners used is preferable.

The composition according to the present embodiment may contain other additives as necessary. The composition according to the present embodiment has high dispersibility due to the inclusion of organic particles, and therefore does not require the addition of a dispersant or the like. Therefore, it is possible to compound a large amount of additives for the purpose of improving other physical properties. There are no particular limitations on the additives, and known additives can be used. Specific examples of such additives include, for example, curing accelerators, colorants, release adjusters, leveling agents, defoamers, tackifiers, conductive materials, plasticizers, ultraviolet absorbers, light stabilizers, softeners, surfactants, antioxidants, and flame retardants.

The content of the organic particles, the different resin, and the hardener is not particularly limited and can be determined according to the intended use, etc. For example, the content of the organic particles in the composition is preferably 0.1 to 60 mass %. The content of the different resin is preferably 5 to 99 mass %. The content of the hardener is preferably 0.01 to 20 mass %.

As a method for producing the composition according to this embodiment, after carrying out each step of the method for producing organic particles described above, a step (mixing step) of mixing the organic particles, a resin, and a curing agent is carried out. The method for the mixing step is not particularly limited, and a known method can be used.

The composition according to this embodiment can be suitably used for producing coating films and laminates, which will be described later. For example, it can be used as a coating liquid for producing a coating film, a coating liquid for forming a functional layer of a laminate, etc.

(coating film)

The organic particles according to this embodiment can be suitably used as a coating film (sometimes called a coating layer, coat layer, coating film, etc.). Such a coating film contains the organic particles. The coating film can be produced by applying a coating liquid containing the organic particles to an object such as a substrate. The coating film can be produced by any method without particular limitation, and known methods can be used. For example, examples of coating methods include a spray method, a roll coater method, and a dip coat method.

(Laminate)

The organic particles according to this embodiment can be suitably used as a laminate material.

Figure 4 is a cross-sectional view of the laminate according to this embodiment.

The laminate 100 includes a substrate 120 and a functional layer 140 formed on at least a portion of the surface of the substrate 120. The functional layer 140 includes organic particles according to this embodiment.

The type of substrate 120 is not particularly limited, and any suitable type can be selected. Specific examples of substrates include glass, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, cellulose triacetate, and cellulose acetate propionate.

The substrate 120 may be a single layer or may be made up of two or more layers.

The functional layer 140 may be, for example, the coating film described above. In addition, by containing other modifiers in addition to the organic particles, the laminate 100 can be given functions other than hydrophilicity.

The organic particles, composition, coating film, and laminate according to the present embodiment described above can be suitably used as various hard coat films. Examples include optical films such as antiglare films, antireflection films, brightness enhancement films, polarizing plates, retardation films, viewing angle compensation films, lens sheets, and diffusion sheets.

In conventional hard coat films, organic additives are added to improve various physical properties, but these tend to have poor dispersibility. Therefore, in order to improve the dispersibility within the hard coat film system, a separate dispersant is added, but this causes problems such as a decrease in other physical properties such as optical properties. In this regard, the organic particles according to this embodiment are organic materials, but have high hydrophilicity, and therefore can exhibit high dispersibility by themselves. Therefore, such problems can be avoided. And since there is no need to add a separate dispersant, the desired additive can be filled into the hard coat film in greater amounts.

As an example, we will explain the case of an anti-glare film used in displays and touch panels of electronic devices. Anti-glare films are used to solve the problem of the display screen becoming difficult to see when light hits the display from the outside and is reflected on the display. However, an anti-glare film that uses organic particles with high hydrophilicity can control the aggregation state of various additives and maintain their dispersibility. As a result, the effect of adding additives such as anti-glare agents can be fully imparted, and high anti-glare properties can be achieved.

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples in any way.

<Example 1>

80 g of acrylic copolymer particles (type of copolymer: methyl methacrylate-acrylic acid copolymer, average particle size: 1 μm, weight average molecular weight: 20000) was placed in a drum-type atmospheric pressure plasma irradiation device 10 (manufactured by J Science Labs, "PLASMA DRUM") having the configuration shown in FIG. 2. Then, for 80 g of the particles, atmospheric pressure plasma treatment was performed at 70 W for 3 hours while flowing helium gas as the inert gas 30 into the reaction vessel under the condition of a flow rate of 2 L/min, to obtain acrylic organic particles. Note that this helium gas was bubbled into methanol and then sent into the reaction vessel of the atmospheric pressure plasma irradiation device 10. The average particle size of the particles was determined by taking the D ₅₀ value of the particle size distribution measured by the laser diffraction/scattering method. In addition, the weight average molecular weight of the particles was determined by the weight average molecular weight (M _w ) calculated in terms of polystyrene obtained by gel permeation chromatography (GPC) analysis.

<Example 2>

Acrylic organic particles were obtained in the same manner as in Example 1, except that the atmospheric pressure plasma treatment time was changed to 1.5 hours.

<Comparative Example 1>

The acrylic copolymer particles were used as is without atmospheric pressure plasma treatment.

<Evaluation of Dispersibility>
A screw tube was filled with 20 mL of water, 1 g of particles was added, and the particles were observed visually. If the particles were dispersed in water, they were judged as "passed", and if they were floating without getting wet, they were judged as "failed". Evaluation was performed under the same conditions immediately after the particle preparation and 30 days after the preparation.

<Hydrophilicity evaluation 1 (water drop area expansion rate)>

(Method for measuring water drop area expansion rate)
First, as shown in FIG. 3, a 100 μm thick coating film made of an organic particle layer was formed on a smooth sample stage T (material: glass) to prepare a sample S. One water droplet W was dropped onto this sample S. Then, the area A ₀ of the water droplet immediately after dropping was calculated from the diameter d ₀ of the water droplet W when viewed from above. Then, two minutes after dropping, the area A f of the water droplet W two minutes after dropping was calculated from the diameter d _f of the water droplet W when viewed from above in the same _manner . Then, the water droplet area expansion rate (D) was calculated based on the following formula (1).
D=A _f /A ₀ ...(1)

(Water drop area expansion rate immediately after film formation)
The sample S was dropped onto a sample holder T, and the water drop area expansion rate (D1) immediately after forming a coating film (immediately after film formation) was determined in accordance with the measurement method described above (first water drop area expansion rate).

(Water drop area expansion rate 30 days after film formation)
The obtained film of sample S was then left to stand for 30 days at room temperature and pressure. After 30 days had passed, the water drop area expansion rate ( _D2 ) was determined in accordance with the above-mentioned measurement method (second water drop area expansion rate _D2 ). The ratio ( _D2 / _D1 ) of the second water drop area expansion rate ( _D2 ) to the first water drop area expansion rate ( _D1 ) was then determined.

Table 1 shows the processing conditions and evaluation results for Examples 1 and 2 and Comparative Example 1.

As shown in Table 1, in both Examples 1 and 2, the dispersibility in water immediately after preparation was "passed", and the dispersibility in water 30 days after preparation was also "passed". Furthermore, the water drop area expansion ratios _D1 and _D2 were also large values. Furthermore, in Examples 1 and 2, the ratio of the water drop area expansion ratios immediately after preparation and 30 days after preparation ( _D2 / _D1 ) was high, and high hydrophilicity was maintained. On the other hand, in Comparative Example 1, the dispersibility in water immediately after preparation and 30 days after preparation was "failed", and the water drop area expansion ratios _D1 and _D2 were low values.

10: Atmospheric pressure plasma irradiation device, 20: Organic particles, 30: Inert gas, 32: Inert gas supply unit, 40: Hydrophilic gas, 42: Hydrophilic gas supply unit, 50: Exhaust gas, 52: Exhaust unit, 60: Hydrophilic solution tank, 70: Mixed gas, 72: Mixed gas supply unit, 100: Laminate, 120: Substrate, 140: Functional layer, S: Sample, W: Water droplet, T: Sample stage, P: Plasma

Claims (5)

The method includes a step of irradiating organic particles containing at least one selected from the group consisting of a (meth)acrylic resin, a styrene resin, an olefin resin, a polycarbonate, silicone, and carbon with atmospheric plasma for 30 minutes to 5 hours in a reaction vessel of a drum-type atmospheric plasma irradiation device while exposing the particles to a hydrophilic gas and an inert gas, thereby obtaining surface-treated organic particles ;
the hydrophilic gas and the inert gas are mixed gases obtained by contacting the inert gas with a liquid of an alcohol, which is a solution containing the hydrophilic gas, before the inert gas is supplied to the reaction vessel;
when a water droplet is dropped onto a film consisting only of the surface-treated organic particles, the water droplet area expansion rate is defined as a ratio of an area of the water droplet viewed from above two minutes after the dropping to an area of the water droplet viewed from above immediately after the dropping, and the water droplet area expansion rate immediately after the formation of the film consisting only of the surface-treated organic particles is 1.1 times or more,
a ratio of the water droplet area expansion rate immediately after the film consisting of only the surface-treated organic particles is formed to the water droplet area expansion rate 30 days after the film is formed, which is 0.9 or more;
A method for producing organic particles for hard coat films . When a water droplet is dropped onto a film consisting of only organic particles that have been surface-treated by atmospheric pressure plasma irradiation while being exposed to a hydrophilic gas, which is an alcohol, and an inert gas using a drum-type atmospheric pressure plasma irradiation device , the ratio of the area of the water droplet as viewed from above two minutes after the dropping to the area of the water droplet as viewed from above immediately after the dropping is defined as the water droplet area expansion rate:
the water droplet area expansion rate immediately after the film consisting of only the surface-treated organic particles is 1.1 times or more;
a ratio of the water droplet area expansion rate immediately after the film consisting of only the surface-treated organic particles is formed to the water droplet area expansion rate 30 days after the film is formed is 0.9 or more;
The organic particles contain at least one selected from the group consisting of (meth)acrylic resins, styrene resins, olefin resins, polycarbonates, silicones, and carbons.
Organic particles for hard coat films . A composition comprising the organic particles according to claim 2 , a resin different from the organic particles, and a hardener. A coating film comprising the organic particles according to claim 2 . A substrate;
A functional layer containing the organic particles according to claim 2 formed on at least a part of a surface of the substrate;
A laminate comprising:

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