JP4881645B2 - Method for manufacturing porous body for antireflection sheet, porous body for antireflection sheet, antireflection film, method for manufacturing antireflection sheet, and antireflection sheet - Google Patents

Description

The present invention relates to a method for producing a porous body for an antireflection sheet . For more porous, the liquid crystal display (LCD), a flat panel display (FPD), organic EL, a display device such as a PDP, for use in the anti-reflection sheet capable of suppressing the deterioration of visibility due to surface reflection of the display device The present invention relates to a method for producing a material.

  Generally, in a display device such as a liquid crystal display (LCD), when the light of a bright light source from the outside is incident on the surface of the display device, the visibility of the screen may be significantly hindered by surface reflection. Therefore, conventionally, an antireflection sheet having an antireflection function is provided on the surface of the display device in order to prevent surface reflection for the purpose of improving the visibility of the screen. As a method of developing the antireflection function, for example, there is a method of reducing the refractive index of the film itself forming the antireflection sheet. However, there is a limit in reducing the refractive index of the film itself. That is, in general, the refractive index of the film itself is determined by the molecular skeleton of the plastic material constituting the film, so that it is difficult to select a film having a desired refractive index.

  Further, as a method of reducing the refractive index of the film itself, there is a method of making the plastic material porous by using the refractive index of air (refractive index 1) and controlling the refractive index by the porosity.

  As a method for making a plastic material porous, Patent Document 1 discloses a method for obtaining a porous body by forming pores with a gas generated by adding a foaming agent to a resin and thermally decomposing the foaming agent. Yes. However, in the method described in Patent Document 1, organic chlorine compounds such as methylene chloride, chloroform, and trichloroethane are used as the foaming agent, and thus there are problems such as safety and environmental pollution. In addition, since the porous body obtained by the method described in Patent Document 1 is considerably large and non-uniform with a pore size of several tens of μm or more, it becomes cloudy when the porous body is formed into a film. Therefore, there is a problem that it cannot be used as an optical application such as an antireflection sheet.

  As a method for making a plastic material porous, Patent Document 2 discloses a method for obtaining a porous body by releasing a pressure after dissolving a gas such as nitrogen or carbon dioxide in a resin at a high pressure. ing. However, even in the porous body obtained by the method described in Patent Document 2, the pore size to be generated is as large as 10 μm or more, and when the porous body is formed into a film, it becomes cloudy and is used as an optical application such as an antireflection sheet. There is a problem that cannot be used.

Therefore, it is possible to use the anti-reflection sheet, for example, a manufacturing method of a porous material pore diameter having the following substantially uniform pores 1μm is desired.

The present invention aims to consideration of the above problems, Ru used for the antireflection sheet, for example, to provide a method for producing a porous body for the anti-reflective sheet pore diameter having the following substantially uniform pores 1μm And

  As a result of intensive studies to solve the above problems, the present inventors have found that the curable resin material is different from the curable resin material and is compatible with the curable resin material. After applying a coating liquid mixed with a predetermined additive that can be insolubilized in a cured product obtained by curing the coating, the coating is formed, the coating is cured, and then the additive from the cured coating is cured. It has been found that a porous body having substantially uniform pores having a pore diameter of 1 μm or less can be produced by removing the above by a predetermined method, and the present invention has been completed.

That is, the present invention provides an acrylate-based curable resin material and an insolubilized product obtained by curing the curable resin material, which is different from the curable resin material and compatible with the curable resin material. A first step of adjusting the coating liquid by mixing an additive which can be dipropylene glycol or tripropylene glycol, a second step of applying the coating liquid to form a coating film, and the coating film Curing treatment is performed, the curable resin material in the coating film is cured to insolubilize the additive, and the cured product has a microphase separation structure in which the insolubilized additive is discontinuously dispersed. A porous body for an antireflective sheet , comprising: a third step of forming a coating; and a fourth step of forming pores by removing the insolubilized additive from the cured coating by heating. A manufacturing method is provided.
Such In the production method, using the above additives to cured phase separation curing the curable resin material compatibility with the curable resin material, to prepare a uniform coating solution, coating The additive that has been insolubilized in the cured product obtained by curing the curable resin material by forming a curing treatment forms a fine microphase-separated structure dispersed discontinuously in the cured product. By removing the added additive by heating, a porous body having substantially uniform pores having a pore diameter of 1 μm or less can be obtained.

Further, in the first step, the present invention further includes a step of adding a solvent to the curable resin material and the additive to prepare a coating solution, and removing the solvent before the curing treatment in the third step. The manufacturing method of the porous body for antireflection sheets of Claim 1 containing this is provided.
In such a production method, a coating solution is prepared by adding a solvent, whereby coating unevenness and the like can be prevented, and a porous body having substantially uniform pores having a pore diameter of 1 μm or less can be obtained.

  Furthermore, in this invention, it is preferable that the said curable resin material is a thermosetting resin material or an ultraviolet curable resin material, and the hardening process in the said 3rd process is a heat processing or an ultraviolet irradiation process.

The method for producing a porous body for an antireflection sheet according to the present invention has an excellent effect that a porous body having substantially uniform pores having a pore diameter of 1 μm or less can be produced. Moreover, since the porous body manufactured by the method for manufacturing a porous body for an antireflection sheet according to the present invention has substantially uniform pores having a pore diameter of 1 μm or less, antireflection for optical applications is used. an excellent effect that can be used as a sheet.

Hereinafter, the manufacturing method of the porous body for antireflection sheets of the present invention will be described for each step.
The method for producing a porous body for an antireflective sheet according to the present invention includes an acrylate-based curable resin material, which is different from the curable resin material and is compatible with the curable resin material. A first step of adjusting the coating liquid by mixing with dipropylene glycol or tripropylene glycol additive which can be insolubilized in the cured product obtained by curing the coating liquid, and forming the coating film by applying the coating liquid A second step of curing the coating film, curing the curable resin material in the coating film to insolubilize the additive, and the insolubilized additive is discontinuous in the cured product. A third step of forming a cured film having a microphase-separated structure dispersed in the film, and a fourth step of forming pores by removing the insolubilized additive from the cured film by heating.

The first step of the present invention is for an acrylate-based curable resin material, and a cured product that is different from the curable resin material and is compatible with the curable resin material and cured the curable resin material. The above-mentioned additive that can be insolubilized can be mixed without a solvent to prepare a coating liquid, or the curable resin material and the additive can be mixed using a solvent to prepare a coating liquid. is there.

  In the present invention, examples of the curable resin material include materials such as monomers, oligomers, and polymers having functional groups that are cured by heat, ultraviolet rays (UV), electron beams (EB), or the like in the molecule. Among the materials, a material having high transparency of the material itself, relatively high surface hardness after curing, and friction resistance is preferably used. By using such a material, a porous body resistant to surface friction can be obtained.

As the curable resin material, if example embodiment, polyethylene glycol, polypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, at least one (meth) of the hydroxyl groups of polyhydric alcohols such as ditrimethylolpropane and dipentaerythritol acryloyloxy Polyol (meth) acrylate based on urethane (meth) acrylate obtained by reacting the polyol (meth) acrylate having at least one hydroxyl group in the molecule with a diisocyanate compound or triisocyanate compound; epoxy resin ( Epoxy (meth) acrylate obtained by reacting with (meth) acrylic acid; tris (2-hydroxyethyl) isocyanuric acid and (meth) acrylic acid or (meth) acrylic acid ester Tris obtained by response (2-hydroxyethyl) isocyanurate (meth) acrylate; oligoester (meth) acrylate. In this invention, these compounds can be used individually or in mixture of 2 or more types.

The additive has a weight average molecular weight of 500 or less and a boiling point of 350 ° C. or less, preferably a boiling point of 300 ° C. or less. If the additive has a weight average molecular weight of 500 or less and a boiling point of 350 ° C. or less, it can be easily removed from the cured product by heating, so that the cured product can be prevented from being deteriorated or thermally deformed. The weight average molecular weight is measured by the method described in the examples. The boiling point is a value measured under normal pressure (about 1.01325 × 10 ⁵ Pa).

The additive is dipropylene glycol or tripropylene glycol .

As a preferable combination of the curable resin material and the additive, for example, polyol (meth) acrylate (particularly at least one selected from the group consisting of pentaerythritol triacrylate, pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate) and an acrylic UV-curable resin material containing species), as combinations of dipropylene glycol or tripropylene glycol.

  The mixing amount of the curable resin material and the additive is 10 to 700 parts by weight, preferably 10 to 500 parts by weight, with respect to 100 parts by weight of the curable resin material. Preferably it is 50-300 weight part. By mixing the additive in the range of 10 to 700 parts by weight with respect to 100 parts by weight of the curable resin material, the formed pore diameter can be reduced to 1 μm or less, and the effect of optical characteristics can be reduced. A level of porosity that can be achieved can be achieved. In addition, when the mixing amount of the additive exceeds 700 parts by weight, there is a possibility that the porosity of the obtained porous body becomes too large and the strength is lowered. Moreover, when the mixing amount of the additive is less than 10 parts by weight, there is a possibility that a porous body used for optical use cannot be obtained because pores are not sufficiently formed.

  In the case of mixing the curable resin material and the additive, a solvent can be used. The solvent used is appropriately selected according to the curable resin material to be used and the additive. Examples of the solvent include aromatic hydrocarbon solvents such as xylene and toluene; alcohol solvents such as methanol, ethanol, and isopropyl alcohol; ketone solvents such as methyl ethyl ketone. The usage-amount of a solvent is 10-500 weight part normally with respect to 100 weight part of said curable resin materials, Preferably it is 30-200 weight part. If the usage-amount of the said solvent is in the said range, a coating nonuniformity, thickness nonuniformity, etc. can be prevented.

  The coating liquid may be mixed with a polymerization initiator that cures the curable resin material. A well-known thing can be used as said polymerization initiator. Examples of the polymerization initiator that cures the curable resin material by heating include organic peroxides such as dibenzoyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide, lauroyl peroxide; -Azo compounds such as azobisisobutyronitrile and 2,2'-azobisisovaleronitrile. Examples of the polymerization initiator that cures the curable resin material by irradiation with light (such as ultraviolet rays) include, for example, acetophenone compounds, benzophenone compounds, diacetyl compounds, benzyl compounds, benzoin compounds, and benzoin ether compounds. , Benzyl dimethyl ketal compounds, benzoyl benzoate compounds, and hydroxyphenyl ketone compounds. The polymerization initiator is used in an amount of 0.01 to 5 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the curable resin material.

  Furthermore, when the curable resin material is cured, various additives may be mixed in the coating liquid to such an extent that the characteristics of the cured film are not impaired. Examples of the various additives include antioxidants such as phenol compounds, amine compounds, sulfur-containing compounds, phosphite compounds, polyhydric alcohol compounds; benzophenone compounds, salsylate compounds, benzotriazoles UV absorbers and light stabilizers such as cyano compounds and cyanoacrylate compounds; fillers such as talc, calcium carbonate, silica, clay, barium titanate, titanium oxide, glass fibers, kaolin clay; glass fibers, glass particles, etc. Reinforcing agent: Anionic surfactant, cationic surfactant, nonionic surfactant, antistatic agent using amphoteric surfactant, nonionic polymer type, cationic polymer type, anionic polymer type Antistatic agents; colorants and the like. In addition, even if it uses the said various additives individually or in combination of 2 or more types, there is no problem.

  Moreover, when the said curable resin material is hardened, the said coating liquid may be mixed with the crosslinking agent which accelerates | stimulates bridge | crosslinking of resin. Examples of the crosslinking agent include polyisocyanate compounds such as diphenylmethane diisocyanate and tolylene diisocyanate, polyepoxy compounds, various metal salt compounds, and chelate compounds. The usage-amount of the said crosslinking agent shall be 20 weight part or less with respect to 100 weight part of said curable resin materials, and can be suitably adjusted within this range. In addition, even if these crosslinking agents are used individually or in combination of 2 or more types, there is no problem.

  As a mixing method for preparing the coating liquid, it is not necessary to adopt any special method, and for example, a general mixing method such as stirring and ultrasonic irradiation is used.

  In the second step of the present invention, the coating solution prepared in the first step is applied to a substrate to form a coating film. The substrate to which the coating liquid is applied may be transparent (transparent substrate) or opaque (opaque substrate) as long as it has a smooth surface. Examples of the transparent substrate include films made of glass and various transparent plastic resins. Moreover, as an opaque base material, metal plates, metal foil, etc., such as stainless steel, copper, and aluminum, are mentioned. The transparent substrate is preferably used as the substrate.

  Examples of the film made of the transparent plastic resin include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; cellulose resins such as diacetyl cellulose and triacetyl cellulose; polycarbonate resins; acrylic resins such as polymethyl methacrylate; Examples thereof include vinyl resins; vinyl acetate resins; films made of various resins such as polyimide resins. In addition, styrene resins such as polystyrene and acrylonitrile-styrene copolymers; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; norbornene resins; various resins such as amide resins such as nylon and aromatic polyamide The film which consists of is also mentioned. Furthermore, an imide resin; a sulfone resin; a polyether sulfone resin; a polyether ether ketone resin; a polyphenylene sulfide resin; a vinyl alcohol resin; a vinylidene chloride resin; a vinyl butyral resin; an arylate resin; Examples of such resins include films made of epoxy resins, blends of the above-mentioned various resins, and the like. In the present invention, one type of the film may be a single layer, or two or more of the same or different films may be laminated.

  The film should be as colorless and transparent as possible, and the transmittance in the wavelength region of 400 to 800 nm is 80% or more, and the transmittance is preferably 90% or more.

  The film made of the transparent plastic resin may be uniaxially stretched or biaxially stretched. The stretching means and the stretching ratio are not particularly limited, but it is preferable to stretch at the same magnification in any of the width direction (MD direction) and the longitudinal direction (TD direction). The draw ratio is 0.5 to 3 times, preferably 1 to 2 times. In general, a plastic resin exhibits birefringence when subjected to a stretching treatment. Therefore, when used for optical applications, the plastic resin is in an unstretched state so as not to disturb the polarization state of liquid crystal cells that have already been set. It is preferable to use a plastic resin as a base material.

  When the substrate is a film made of the transparent plastic resin, at least one surface may be subjected to various surface treatments such as corona treatment, ultraviolet (UV) treatment, or electron beam (EB) treatment. By performing the surface treatment on the film surface, adhesion between the cured film obtained by curing the coating liquid and the film is improved.

  Although the thickness of the base material can be determined as appropriate, it is generally 10 to 300 μm, preferably 30 to 200 μm, from the viewpoints of workability such as strength, handleability, and thin film properties.

  As a means for applying the coating liquid onto the substrate, for example, a continuous coating apparatus or the like can be used. The continuous coating apparatus is capable of continuously supplying the coating liquid to the coating apparatus, and extruding the coating liquid onto a film-like substrate continuously from a discharging means such as a die. It is. As a means for applying the coating liquid on the substrate, other appropriate means such as a wire bar, kiss coat, and gravure can be used. In addition, examples of means for applying the coating liquid onto the substrate by a single wafer method include means such as an applicator, a Meyer bar, a knife coater, and a spin coater. Further, the coating liquid is continuously applied onto an endless belt made of metal or the like, a coating film is formed, a cured coating film is formed through a process described later, and peeled from the endless belt. A cured film may be formed.

  In the third step of the present invention, the coating film formed in the second step is subjected to a curing treatment, the curable resin material in the coating film is cured to insolubilize the additive, and insolubilized in the cured product. A cured film having a microphase separation structure in which additives are dispersed discontinuously is formed. The insolubilized additive forms a microphase-separated structure dispersed discontinuously, whereby fine pores are formed through the steps described below.

  As said hardening process, the hardening method corresponding to the curable resin material to be used can be employ | adopted suitably. That is, when the curable resin material is an ultraviolet curable resin material, the coating film may be irradiated with ultraviolet rays to cure the resin, and the curable resin material is a thermosetting resin material. In some cases, it may be heated and cured. In addition, when the coating liquid contains a solvent, after the coating film is formed on the substrate using the coating means, the solvent is removed using a method such as heat removal or reduced pressure removal. A curing process is performed later.

  In the fourth step of the present invention, the insolubilized additive is removed from the cured coating formed in the third step by heating to form pores in the cured coating. By removing the insolubilized additive from the cured film, the portion occupied by the additive in the cured film is removed, and a porous body having very fine pores is formed.

  Examples of the method for removing the insolubilized additive from the cured coating include a method of heating under normal pressure and a method of heating under reduced pressure. The heating device used when removing the insolubilized additive is not particularly limited, and may be appropriately selected from general devices according to the heat-resistant temperature of the substrate to be used, the kind of additive to be used, and the like. Can do.

The temperature at which the additive is removed is 300 ° C. or less, preferably 200 ° C. or less, more preferably 100 ° C. to 160 ° C. under normal pressure (about 1.01325 × 10 ⁵ Pa). If the temperature at the time of removing the additive is within the above range, the additive is gently removed, the microphase separation structure in the cured product is maintained as it is, and desired pores are obtained, Further, deformation of the base material can be suppressed. If the temperature at which the additive is removed is set to be equal to or higher than the boiling point of the additive, the additive may cause a sudden volume change from liquid to gas, and the cured coating may be destroyed and desired vacancies may not be obtained. is there.

  If the insolubilized additive is removed under reduced pressure, the heating temperature can be further lowered. This is because the boiling point of the additive used by reducing the pressure is lowered.

  If the method of removing the insolubilized additive by heating is used, the additive can be easily removed. Further, the amount of the organic solvent used can be reduced as compared with the case where the additive is removed by the organic solvent.

  By removing the insolubilized additive from the cured coating, a porous body having pores is formed.

The average pore diameter of the porous body for an antireflection sheet produced by the production method of the present invention is 1 μm or less, preferably 100 nm or less. When the average pore diameter is 1 μm or less, the optical characteristics when used as an antireflection sheet such as light scattering can be suppressed. The size of the average pore diameter can be adjusted to a predetermined size by adjusting the amount of mixing the curable resin material and the additive. The average pore diameter is measured by the method described in the examples.

The porosity of the porous body for an antireflection sheet produced by the production method of the present invention is 5 to 50%, preferably 5 to 40%. When the porosity is within the above range, a porous body that exhibits optical characteristics and is sufficient in strength can be obtained. The porosity can be adjusted by the mixing amount of the curable resin material and the additive. The porosity is measured by the method described in the examples.

The thickness of the porous body for an antireflection sheet produced by the production method of the present invention is not particularly limited, but is 0.5 to 30 μm, preferably 3 to 20 μm. If the thickness of the porous body exceeds 30 μm, there is no particular adverse effect. However, increasing the thickness leads to a reduction in handling. Moreover, when the thickness of the porous body is less than 0.5 μm, the characteristics required for the surface layer of the optical film are not sufficiently exhibited, and there is a possibility that the wear resistance is particularly lowered.

An antireflection film having an antireflection function can be produced using the method for producing a porous body for an antireflection sheet of the present invention. Moreover, the antireflection sheet which prevents the surface reflection of a display apparatus can be manufactured by forming the antireflection film on a transparent base material using the manufacturing method of the porous body for antireflection sheets of the present invention. . In addition, as the transparent substrate, a film made of the above-described transparent plastic resin can be used. Further, when a friction-resistant curable resin material is used when manufacturing the antireflection sheet, it is possible to form a surface protective layer of a display device having friction resistance and an antireflection function.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.

(Measurement method of weight average molecular weight)
The weight average molecular weight is a value converted by standard polystyrene by the GPC method. An HLC-8120GPC manufactured by Tosoh Corporation was used as the GPC body, a column temperature of 40 ° C., a pump flow rate of 0.5 ml / min, and a detector RI. Data processing is performed using standard polystyrene calibration curves with known molecular weights in advance (molecular weights of 20.6 million, 8.42 million, 4.48 million, 1.11 million, 707,000, 354,000, 188,000, 98,000, 372,000, 171,000, 9830, 5870, A calibration curve was prepared using standard polystyrenes of 2500, 1050 and 500), and the molecular weight was determined from the converted molecular weight.
Column used: TSKgel GMH-H (S) × 2 (manufactured by Tosoh Corporation) was used in series.
Mobile phase: Tetrahydrofuran Injection volume: 100 μl
Sample concentration: 1.0 g / l (tetrahydrofuran solution)

(Measurement method of total light transmittance and specular reflectance)
The total light transmittance was measured in the wavelength range of 400 nm to 700 nm using a spectrophotometer (manufactured by Shimadzu Corporation, spectrophotometer “MPS-2000”) and an integrating sphere. The specular reflectance was measured with the same type of measuring device.

(Porous body morphology observation method)
The prepared porous sheet was cooled in liquid nitrogen and ruptured. After gold was vapor-deposited on the fracture surface, it was observed at an acceleration voltage of 12 kV using a scanning electron microscope (manufactured by Hitachi, Ltd .: model name “S-570”).

(Measuring method of average pore diameter)
The scanning electron micrograph of the sheet cross section of the prepared porous material was binarized using image processing software (trade name “Optimas” manufactured by Argo Co., Ltd.), and the average pore diameter was determined. In addition, the image processing was performed assuming that the cross-sectional shape was a circle in a portion having an irregular shape.

(Measurement method of porosity)
The scanning electron micrograph of the cross section of the created porous material is binarized using image processing software (trade name “Optimas”, manufactured by Argo Co., Ltd.) to form pores and cured resin parts. The porosity was calculated from the area ratio. The following formula (1) was used to calculate the porosity.
Porosity = Area of hole part / (Area of hole part + Area of cured resin part) × 100 (1)

Example 1
Acrylate-based resin (Dainippon Ink Industries, trade name “Unidic”: Tris- (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol triacrylate, dipentaerystol hexaacrylate, pentaerythritol tetraacrylate and (Mixture of isophorone diisocyanate polyurethane) 106 parts by weight of toluene and 100 parts by weight of α-aminoketone initiator (Ciba Specialty Chemicals, trade name “Irgacure 907”) were mixed. Add 100 parts by weight of dipropylene glycol (manufactured by Kishida Chemical Co., Ltd., molecular weight: 134, boiling point: 232 ° C.) as an additive to the solution, and then add 3180 parts by weight of toluene and stir to obtain a transparent uniform coating solution. It was. The coating solution was applied onto a polyethylene terephthalate film (film thickness 125 μm) using a wire bar so that the coating thickness after standing for 5 minutes in a dryer at a temperature of 25 ° C. was 500 nm.
The film coated with the coating solution was irradiated with ultraviolet rays at an illuminance of 300 mJ / cm ² for 20 seconds to be cured. The cured film was cut into strips of 100 mm × 150 mm and held for 10 minutes in a drier heated to 150 ° C. under normal pressure (about 1.01325 × 10 ⁵ Pa) to remove the additive. The residual amount of the additive after removal evaluated by gas chromatography was 1% by weight or less. A scanning electron micrograph of the cross section of the obtained porous material is shown in FIG. Further, the average pore diameter, porosity, transmittance and specular reflectance of the obtained porous material were measured and shown in Table 1.

(Example 2)
The same operation as in Example 1 was performed except that tripropylene glycol (molecular weight: 193, boiling point: 268 ° C.) was used as an additive. A scanning electron micrograph of the cross section of the obtained porous material is shown in FIG. Further, the average pore diameter, porosity, transmittance and specular reflectance of the obtained porous material were measured and shown in Table 1.

(Example 3)
4 parts by weight of an α-aminoketone initiator (trade name “Irgacure 907”, manufactured by Ciba Specialty Chemicals Co., Ltd.) is mixed with 100 parts by weight of dipentaerythritol hexaacrylate, and dipropylene glycol (Kishida Chemical) is used as an additive. 250 parts by weight (manufactured by Co., Ltd., molecular weight: 134, boiling point: 232 ° C.) was added, and 3150 parts by weight of toluene was further added and stirred to obtain a transparent and uniform coating solution. Using a wire bar on the hard coat-treated surface of the triacetyl cellulose film (film thickness 75 μm) that has been hard-coated with the coating solution, the coating thickness after standing for 5 minutes in a dryer at a temperature of 25 ° C. is 300 nm. It was applied as follows. The film coated with the coating solution was irradiated with ultraviolet rays at an illuminance of 300 mJ / cm ² for 20 seconds to be cured. The cured film was cut into strips of 100 mm × 150 mm and held for 10 minutes in a dryer heated to 140 ° C. under normal pressure (about 1.01325 × 10 ⁵ Pa) to remove the additive. The residual amount of the additive after removal evaluated by gas chromatography was 0.2% by weight. A scanning electron micrograph of the cross section of the obtained porous body is shown in FIG. Further, the average pore diameter, porosity, transmittance and specular reflectance of the obtained porous material were measured and shown in Table 1.

(Comparative Example 1)
The same operation as in Example 1 was performed except that the additive was not used.
In addition, although the obtained porous body cross section was observed with the scanning electron microscope, the void | hole did not exist.

(Comparative Example 2)
The same operation as in Example 1 was performed except that 100 parts by weight of polyethylene glycol having a weight average molecular weight of 1,000 was used as an additive. The average pore diameter, porosity, transmittance and specular reflectance of the obtained porous material were measured and shown in Table 1. The residual amount of the additive after removal as evaluated by gas chromatography was 80% by weight, and was not completely removed.

  The porous body was obtained by removing the additive by heating.

2 is a scanning electron micrograph of a magnification (20,000 times) of the cross section of the porous material obtained in Example 1. FIG. 4 is a scanning electron micrograph of a magnification (20,000 times) of the cross section of the porous material obtained in Example 2. FIG. The scanning electron micrograph of the magnification (100,000 times) of the cross section of the porous body obtained in Example 3.

Claims (7)

An acrylate-based curable resin material and dipropylene glycol that is different from the curable resin material and is compatible with the curable resin material and insoluble in a cured product obtained by curing the curable resin material, or A first step of adjusting the coating liquid by mixing an additive which is tripropylene glycol ;
A second step of applying the coating liquid to form a coating film;
The coating film is subjected to curing treatment, the curable resin material in the coating film is cured to insolubilize the additive, and the insolubilized additive is discontinuously dispersed in the cured product. A third step of forming a cured film having a structure;
A method for producing a porous body for an antireflective sheet , comprising: a fourth step of removing the insolubilized additive from the cured coating by heating to form pores. The said 1st process further includes the process of adding a solvent to the said curable resin material and the said additive, preparing a coating liquid, and removing a solvent before the hardening process of the said 3rd process. Of producing a porous body for an antireflection sheet . The porous for an antireflection sheet according to claim 1 or 2, wherein the curable resin material is a thermosetting resin material or an ultraviolet curable resin material, and the curing treatment in the third step is a heat treatment or an ultraviolet irradiation treatment. A method for producing a mass. The porous body for antireflection sheets obtained by the manufacturing method of the porous body as described in any one of Claim 1 to 3. An antireflection film comprising a porous body for an antireflection sheet according to claim 4.   A method for producing an antireflection sheet, wherein the antireflection film according to claim 5 is formed on a transparent substrate.   An antireflection sheet obtained by the production method according to claim 6.