JP4843896B2 - Photopolymerizable composition for forming porous pattern, method for forming porous pattern using the same, and porous pattern - Google Patents

Description

  The present invention relates to a photopolymerizable composition for forming a porous pattern capable of forming an excellent cavity pattern based on a highly controlled structure, a method for forming a porous pattern using the same, and a porous pattern It is about.

  Structures containing cavities inside are used in various fields. For example, foam used for cushioning materials, heat insulating materials, etc., separation membrane used for production of ultrapure water, purification of chemicals, water treatment, etc., waterproof and moisture permeable film used for sanitary applications, batteries It is used in various industrial fields such as porous films used for separators and the like, and void-containing sheets used as reflective substrates for liquid crystal displays and various lighting fixtures.

The manufacturing methods of these structures are classified into the following methods.
(1) A method in which a thermal foaming material is kneaded into a raw material resin to form a sheet, and then crosslinked by an electron beam and then foamed by heating (see, for example, Patent Document 1).
(2) A method in which a photodegradable compound is added to a raw material resin, coated on a substrate, and then irradiated with active energy rays to decompose and foam (see, for example, Patent Document 2).
(3) Wet material resin is dissolved in a good solvent, molded into an arbitrary shape such as a hollow fiber, a film, etc., and the resulting molded body is immersed in a poor solvent, and a wet process utilizing the two-phase separation phenomenon that occurs at that time A method obtained by a phase change method (see, for example, Non-Patent Document 1).
(4) Dissolve raw resin and high-boiling poor solvent in low-boiling good solvent, apply on substrate, volatilize only good solvent, and perform two-phase separation phenomenon between raw resin and poor solvent A method obtained by a dry phase conversion method in which a poor solvent is volatilized after the occurrence (see, for example, Patent Document 3).
(5) After adding and molding particles made of an inorganic filler such as silica, alumina, inorganic salts or incompatible resin to the raw material resin, the obtained molded body is stretched, and the resin and inorganic filler, etc. A method based on an interface peeling method in which the interface is peeled off to make it porous (see, for example, Patent Document 4).
(6) A thermoplastic resin and its thermoplastic resin are mixed with a latent solvent that is a non-solvent near room temperature but a solvent at high temperatures, and once mixed, then cooled and solidified to form a resin phase. A method using a thermally induced phase separation method in which a porous body is obtained by phase separation into a solvent phase and then removing the high-temperature solvent by extraction or the like (see, for example, Non-Patent Document 2)
Etc.
JP-A-3-221542 (page 2-3) Japanese Patent Laid-Open No. 5-72727 (page 2-3) JP-A-11-71476 (page 6-18) JP-A-5-194773 (page 3-6) Hiroyoshi Kawakami, “Membrane”, Vol. 26, No. 3, p. 110-115 (2001) Hideto Matsuyama, “Membrane”, Vol. 26, No. 3, p. 116-123 (2001)

  However, these methods show a method of forming cavities on the entire surface of the sheet, and do not lead to a method of forming cavities only at desired locations in the sheet.

  However, although patterning of cavities using the method (2) is known, it is difficult to control the foam diameter, and contrast is obtained because the foam is also mixed in parts where foaming is not desired. For this reason, there are problems such as a complicated process and a difficulty in neutralization because most of the foam is colored.

  In view of the background of such prior art, the present invention provides a porous pattern-forming composition, a porous pattern, and a porous pattern having a controlled structure, which can be formed only in a desired place by an easy process. The formation method is intended to be provided.

  The present invention employs the following means in order to solve such problems. That is, the photopolymerizable composition for forming a porous pattern of the present invention is a composition comprising at least three of a binder resin, a photosensitive compound and a photopolymerization initiator, and the photosensitive compound is composed of the binder resin. It is soluble in a poor solvent, and the proportion of the photosensitive compound in the total solid content is 30 to 80% by weight.

  Further, the porous pattern forming method of the present invention is such that after the photopolymerizable composition for forming a porous pattern is coated on a substrate to form a coating film, the coating film is subjected to a desired pattern. The electromagnetic wave is irradiated, and then immersed in a poor solvent for the binder resin, and then the poor solvent that has penetrated into the coating film is volatilized to make the irradiated or non-irradiated part porous. It is a feature.

  Further, the porous pattern of the present invention obtained by such a method for forming a porous pattern has a structure in which a porous phase composed of continuous pores and a transparent phase substantially free of voids are alternately arranged. It is characterized by.

  According to the present invention, a porous pattern having a controlled structure can be formed by an easy process, and the obtained pattern can be suitably used in various fields, particularly in the field of optical functional elements.

  The present invention has been intensively studied on the above-mentioned problem, that is, a porous pattern forming composition capable of forming a porous pattern with a controlled structure in a desired process and only at a desired location, a binder resin, In the composition consisting of at least three of the photosensitive compound and the photopolymerization initiator, the proportion of the photosensitive compound in the total solid content was controlled within a specific range. It has been investigated.

  It is essential that the photopolymerizable composition for forming a porous pattern of the present invention is a composition comprising at least three of a binder resin, a photosensitive compound and a photopolymerization initiator.

  Examples of such binder resins include polyester resins such as polyethylene terephthalate, polyethylene-2, 6-naphthalate, polypropylene terephthalate, and polybutylene terephthalate, polyolefin resins such as polycarbonate, polystyrene, polyethylene, polypropylene, and polymethylpentene, polyamide, Thermoplastic resins such as polyethers, polyesteramides, polyetheresters, polyvinyl chloride, poly (meth) acrylic acid esters, polyvinyl alcohol and copolymers containing these as main components, or mixtures thereof are preferably used. Here, the resin is preferably transparent.

  Here, the term “transparent” means that light passes through the resin material substantially straight. Moreover, there is no special restriction | limiting in the molecular weight of binder resin, A high molecular weight body, an oligomer, and a low molecular weight binder can also be used.

  As the photosensitive compound used in the present invention, a photosensitive compound that is decomposed by the action of electromagnetic waves, a photosensitive compound that reacts within or between molecules by the action of electromagnetic waves, and the like are used. A compound that decomposes due to the action of electromagnetic waves means that the compound itself absorbs electromagnetic waves when irradiated with electromagnetic waves, the main chain is decomposed by the absorbed energy, and the electromagnetic waves are irradiated by the coexistence of a photoacid / base generator. In the present invention, there can be used those which become soluble in the solvent when the acid / base generated is present, and those whose side chain functional group is decomposed by the action of electromagnetic waves.

  The compound itself absorbs electromagnetic waves by electromagnetic wave irradiation, and the main chain is decomposed by the absorbed energy, such as polydimethylsilane, polymethylphenylsilane, etc. Polyacryl methacrylates such as PMMA are used.

  Examples of substances that become soluble in the presence of the acid / base generated by irradiating electromagnetic waves with the coexistence of photoacid / base generators are solvent-soluble: hexaammonium cobalt perchlorate, hexapropylamine cobalt perchlorate, hexa Methylamine cobalt perchlorate, bromopentammonium cobalt perchlorate, [[(2-nitrobenzyl) oxy] carbonyl] methylamine, [[(2-nitrobenzyl) oxy] carbonyl] ethylamine, [[( A combination of a photobase generator such as 2-nitrobenzyl) oxy] carbonyl] propylamine and a base water-soluble resin such as polyacrylic acid can be used.

  In addition, as the functional group of the side chain which is decomposed by the action of electromagnetic waves, a diazo resin having a diazo group in the side chain, a resin having an azide group, or the like is used, but is not limited thereto.

  In addition, the crosslinkable compound that reacts and polymerizes within a molecule or between molecules by the action of electromagnetic waves is a compound that absorbs electromagnetic waves and crosslinks between molecules and within the molecule by the absorbed energy, or Any one that crosslinks by irradiation with electromagnetic waves in the presence of a photopolymerization initiator can be used.

  Examples of the former include those having a photodimerization reactive structure such as (aza) stilbene, cinnamic acid, naphthalene, anthracene, coumarin, and thymine in the molecule, and examples of the latter include a vinyl group, Vinylidene group, acryloyl group, methacryloyl group [Hereinafter, acryloyl group and methacryloyl group are collectively referred to as (meth) acryloyl group. The same expression is used for (meth) acryl, (meth) acrylate, and the like. ] Having a structure such as a maleimide group or the like can be used. Among these, a compound having a (meth) acryloyl group is preferably used because of its high crosslinking rate.

Examples of such a crosslinkable compound having a (meth) acryloyl group include the following.
(1) Monofunctional compounds; alkyl (meth) acrylates such as ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and isobornyl (meth) acrylate , 2-hydroxylethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, hydroxypropyl (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl acrylate, methyl α -(Hydroxymethyl) acrylate, ethyl α- (hydroxymethyl) acrylate, n-butyl α- (hydroxymethyl) acrylate, tris (2-hydroxy) isocyanurate Acrylates having a hydroxyl group such as diacrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid glycerol monomethacrylate, 2- (meth) acrylic Acrylates having a carboxylic acid group such as leuoxyethyl-succinic acid, 2- (meth) acryloyloxyethyl-phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, phenyl (meth) acrylate, phenyl Alkyl-terminated polyalkylene glycol mono (meth) acrylates such as cellosolve (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, acryloylmol Phosphorus, N- isopropyl (meth) (meth) acrylamides such as acrylamide, and other (meth) compound having one acryl group in one molecule.

  (2) Bifunctional compound; tris (2-hydroxy) isocyanurate diacrylate, 3-acryloyloxyglycerin monomethacrylate, glycerin dimethacrylate, 1,6-hexanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate , Hydroxypivalic acid neopentyl glycol di (meth) acrylate, 2,2′-bis (4- (meth) acryloyloxypolyethyleneoxyphenyl) propane 2,2′-bis (4- (meth) acryloyloxypolypropyleneoxyphenyl) ) Propane, dicyclopentanyl di (meth) acrylate, phenylglycidyl ether acrylate tolylene diisocyanate, divinyl adipate, and other compounds having two (meth) acryl groups in one molecule.

  (3) Trifunctional compounds; pentaerythritol tri (meth) acrylate trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, tris [(meth) acryloyloxyethyl] isocyanate, ) A compound having three acrylic groups.

  (4) Tetrafunctional compound; pentaerythritol tetra (meth) acrylate, glycerin di (meth) acrylate hexamethylene diisocyanate, and other compounds having four (meth) acryl groups in one molecule.

  (5) pentafunctional compound; dipentaerythritol monohydroxypenta (meth) acrylate, and other compounds having five (meth) acryl groups in one molecule.

  (6) Hexafunctional compound; dipentaerythritol hexa (meth) acrylate and other compounds having six (meth) acryl groups in one molecule.

  In addition, (meth) acrylic ester of epoxy resin such as bisphenol A-diepoxy- (meth) acrylic acid adduct, (meth) acrylic ester of polyether resin, (meth) acrylic ester of polybutadiene resin, A compound in which a resin is modified and a crosslinkable substituent such as a (meth) acryloyl group is introduced into the molecule, such as a polyurethane resin having a (meth) acryl group at the molecular end, can also be used. These may be used alone or as a mixture of two or more compounds.

  Such binder resin and photosensitive compound are preferably used in a compatible combination among the above compounds. However, even in the case of phase separation, for example, those that become compatible and transparent by external stimuli such as temperature, electric field, and magnetic field can be preferably used.

  Moreover, it is essential that the photosensitive compound used in the present invention is dissolved in a poor solvent for the binder resin. That is, as such a photosensitive compound, it is important to use a compound having the following characteristics with respect to the poor solvent of the binder resin. That is, when the photosensitive compound is decomposed by electromagnetic waves, it is excellent in solubility with decomposition products, and when the photosensitive compound is crosslinked by electromagnetic waves, it is excellent in solubility of unreacted photosensitive compounds. Is used.

  Here, the poor solvent for the binder resin refers to a solvent that does not completely dissolve the binder resin but slightly swells. For example, as a poor solvent when a polyester resin is used as the binder resin, Water, alcohols such as methanol and ethanol, acetone, butyl acetate, toluene, xylene and the like can be used. These may be used alone or in combination of two or more. In selecting such a poor solvent, it is necessary to select in consideration of the compatibility between the binder resin and the photosensitive compound. Moreover, since this poor solvent is what is finally removed from a coating film, what evaporates as easily as possible is used preferably. However, this also needs to be considered including process aspects such as applicability.

  The photopolymerization initiator preferably used in the present invention is not particularly limited as long as it matches the wavelength of the electromagnetic wave to be irradiated. For example, 2,2-dimethoxy-1,2-diphenylethane-1-one , Acetophenones such as p-tert-butyltrichloroacetophenone, 2,2′-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, 4,4′-bisdimethylaminobenzophenone , Ketones such as 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, benzoin ethers such as benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldimethyl ketal, hydride Benzyl ketals such as loxycyclohexyl phenyl ketone are used.

  Further, a solvent may be used in order to facilitate mixing of these compositions. In this case, it is preferable that other components are well dissolved in this solvent. The solvent preferably used is not particularly limited as long as it dissolves the above composition uniformly. For example, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate, ethyl lactate and γ-butyrolactone are used. Solvents, alcohol solvents such as methanol, ethanol and ethylene glycol; amide solvents such as N, N-dimethylformamide; hydrocarbon solvents such as cyclohexane and toluene; chlorine solvents such as dichloromethane and chloroform; Methyl pyrrolidone, dimethyl sulfoxide, water and the like are used. These may be used alone or in combination of two or more, and can be appropriately selected in consideration of the solubility of the composition, the coating property of the coating film, and the like. However, if possible, the absence of solvent is preferable in that the drying step can be omitted.

  Moreover, various additives can be added to the photopolymerizable composition for forming a porous pattern of the present invention as long as the effects of the present invention are not lost. Examples of additives to be added include, for example, fillers such as inorganic fine particles, pigments, dyes, fluorescent brighteners, antioxidants, heat resistance agents, light resistance agents, weather resistance agents, antistatic agents, polymerization inhibitors, and mold release agents. Agents, thickeners, pH adjusters, salts and the like are used.

  In the photopolymerizable composition for forming a porous pattern of the present invention, it is essential that the proportion of the photosensitive compound in the total solid content is 30 to 80% by weight.

  By setting it as such a range, in the extraction process of a manufacturing process, efficient extractability, favorable coating agent characteristics, and flatness of a coating film can be ensured. In other words, if it is less than 30%, extraction becomes difficult, and as a result, even if it cannot be made porous, or even if it can be made porous, the efficiency tends to deteriorate, for example, it takes a very long time. Further, in the case where it exceeds 80%, even if it is cured, the photosensitive compound that cannot be completely cured remains, and the poor solvent penetrates into the cured part and becomes porous. There is a tendency to be inferior in form retention as.

  The method for forming a porous pattern of the present invention comprises at least coating a composition comprising a binder resin, a photosensitive compound, and a photopolymerization initiator on a substrate, performing electromagnetic wave irradiation according to a desired pattern, and forming a binder resin. After being immersed in a poor solvent for, the poor solvent that has permeated the inside is volatilized to make the irradiated or non-irradiated part porous.

  The composition can be applied by multi-roll coating, blade coating, wire bar coating, slit die coating, gravure coating, knife coating, reverse roll coating, spray coating, offset gravure coating, spin coating and the like. . It can be appropriately selected depending on the coating film thickness.

  Regarding the exposure step, examples of the electromagnetic wave referred to in the present invention include electron beam, γ-ray, X-ray, ultraviolet ray, visible ray, etc. Among them, it is preferable to use ultraviolet ray for convenience of apparatus and handling. Examples of the pattern exposure method include irradiation through a photomask and writing by laser scanning. In terms of productivity, batch exposure through a photomask is more preferable. Here, since there is a concern about surface polymerization inhibition in the presence of oxygen, for example, whether exposure is performed in an inert gas atmosphere such as nitrogen, or whether the exposure is performed after laminating a cover film on the coating film surface, etc. It is preferred to eliminate the effects of inhibition.

  Regarding the extraction process, the extractability depends on the penetration rate (diffusion rate) of the poor solvent, but it is required to shorten the extraction time in order to increase the productivity. For this reason, for example, the extraction temperature, that is, the temperature of the poor solvent is increased, ultrasonic treatment is performed, or an extraction auxiliary agent that has high affinity with the poor solvent and promotes penetration into the coating film is added. Preferably used.

  The poor solvent drying step is carried out by steps such as heating, vacuum drying, and freeze drying, thereby forming a porous layer. In the case of heat drying, the poor solvent can be removed without destroying the porous structure by treating the binder resin alone or below the glass transition temperature of the crosslinked resin.

  Here, the principle of making porous in the present invention is as follows. A coating film composed of a binder resin, a photosensitive compound, and a photopolymerizable compound is immersed in a poor solvent for the binder resin. Here, only the photosensitive compound that can be dissolved in the solvent elutes while maintaining the form of the binder resin. Thus, the photosensitive compound and the solvent are substituted, and the solvent that has entered the inside causes poor phase separation because it is a poor solvent for the binder resin. Thereafter, by evaporating the solvent, the portion where the poor solvent was present is made porous.

  In the present invention, the part to be made porous can be selected from either an electromagnetic wave irradiation part or an unirradiated part. This is because the permeability of the poor solvent into the film can be changed by electromagnetic wave irradiation. In other words, when a compound that decomposes due to the action of electromagnetic waves is used as the photosensitive compound, the decomposition product generated at the irradiated site is easily extracted by the poor solvent, and the non-irradiated site eliminates the penetration of the poor solvent. Is retained. In addition, when a compound that crosslinks and reacts within or between molecules by electromagnetic waves is used, the photosensitive compound or oligomer remaining in the unirradiated site is extracted, and the irradiated area is transparent because it eliminates penetration of poor solvents. Is retained. In both cases, the poor solvent is infiltrated, phase separation occurs between the binder resin and the poor solvent, and then the solvent is volatilized to selectively make the pattern irradiated or unirradiated site porous. It becomes possible to do.

  Preferably, the photosensitive compound is a compound that reacts within or between molecules with an electromagnetic wave and undergoes cross-linking polymerization, irradiates the electromagnetic wave according to a desired pattern to cure the irradiated part, and then is immersed in a poor solvent for the binder resin. Then, the photosensitive compound in the uncured part is extracted, and the poor solvent soaked in the interior is volatilized to selectively make the unirradiated part porous.

  In addition, it is preferable to include a step of irradiating the entire surface with electromagnetic waves while the film contains the solvent after being immersed in a poor solvent. Such post-exposure is preferable because the porous structure of the extraction part is fixed, and the change with time of the porous structure can be suppressed. This is because it is difficult to completely extract the photosensitive compound when immersed in a poor solvent, but the porous structure of the extraction part is fixed by curing the remaining photosensitive compound without being extracted by post-exposure. This is because

  The porous structure can be controlled by the composition ratio, the type of immersion poor solvent, various process conditions, and the like.

  For example, when the binder resin to be used is a polyester-based resin, when the poor solvent is an alcohol with a short chain length such as methanol, a porous structure with a small pore size and a dense packing is used, and an alcohol with a long chain length is used. In some cases, the hole diameter can be increased.

  The porous pattern of the present invention is produced by using the composition and the production method as described above, and the structure is a porous phase composed of continuous pores and a transparent phase substantially free of voids inside. Are porous patterns arranged alternately. Here, the continuous hole means that each hole is connected two-dimensionally or three-dimensionally, and the porous phase composed of continuous holes means that at least the continuous holes are included.

  1A to 1G are cross-sectional views for illustrating the shape of the porous phase 1 in the cross-section of the porous pattern of the present invention. The shape of the porous phase 1 observed in the cross section is rectangular (FIGS. 1 (a), (f), (g)), trapezoid (FIG. 1 (b)), triangle (FIG. 1 (c)). Those deformed (FIGS. 1D and 1E) and those mixed with these are preferably used, but shapes other than these can also be used. That is, in addition to FIG. 1A in which the porous phase 1 having a rectangular cross section is substantially perpendicular to the sheet surface, the forms shown in FIGS. 1B to 1E are also included. Further, as shown in FIGS. 1 (f) and (g), the porous layer 1 does not exist in the vicinity of the upper surface and / or the lower surface of the functional layer, and the upper surface and / or the lower surface of the functional layer is transparent. 2 is preferably used.

  2A and 2B are perspective views schematically showing a part of the porous pattern, the upper surface of the figure corresponds to the surface of the porous pattern, and the vertical direction of the figure is the thickness direction of the functional layer. Equivalent to. As an arrangement structure of the porous phase 1 in the functional layer, for example, as shown in FIG. 2A, the porous phase 1 extends in a stripe shape in the plane direction, and as shown in FIG. A structure or the like in which the mass phase 1 spreads in a lattice shape in the plane direction is used, but is not limited thereto. As shown in FIGS. 3A to 3D, the transparent phase 2 may have a shape selected from a substantially triangular shape, a substantially rectangular shape, a substantially hexagonal shape, a circle, and an ellipse. The transparent phase 2 may be aligned as illustrated, or may be arranged at random.

  In the porous pattern of the present invention, the ratio (L / p) between the length L of the transparent phase in the sheet thickness direction and the minor axis length p of the transparent phase in the cross section in the plane direction can be arbitrarily set. .

  Here, the short axis length p of the transparent phase 2 is the unit length of the transparent phase as illustrated in FIG. In the case of the stripe pattern shown in FIG. 2, the measurement is performed in the direction in which the unit length is short. If the transparent phase is a circle, the diameter of the transparent phase 2 is the short axis. If the polygon is a polygon such as a triangle or a rectangle, the diameter of the inscribed circle is the short axis length p of the transparent phase 2. Good. Moreover, the length L of the transparent phase in the sheet thickness direction indicates the thickness of the transparent phase 2 as shown in FIG.

  Further, in this arrangement layer, the area ratio of the transparent phase 2 and the porous phase 1 is arbitrary in the section in the sheet surface direction in the arrangement layer.

  Here, the length unit of the transparent phase and the length unit of the porous phase are represented by the lengths of p and t in the case of FIG. In addition, when the length unit changes with positions like FIG.1 (b) etc., it represents with the average value.

  The porous pattern of the present invention may be a single layer sheet as described above, but may be formed on a base film from the viewpoint of mechanical strength, heat resistance, ease of handling, etc. of the sheet itself. . When formed on a base film, as the base film, for example, a film obtained by biaxially stretching a polyester-based resin such as polyethylene terephthalate or polyethylene-2,6-naphthalate is preferably used.

  In addition, since the porous pattern of the present invention has a smooth surface, an antistatic layer, a hard coat layer, etc. are formed on the surface, other coating films, films, etc. are laminated, or high-order processing is performed. Is also possible.

  As a use of the pattern composed of the porous phase and the transparent phase thus obtained, conventionally used cushioning materials, heat insulating materials, separation membranes, waterproof and moisture permeable films, porous membranes, liquid crystal displays and optical devices are used. In fields such as circuit members and various lighting fixtures, the film can be used as a film in which a porous phase is patterned only in a desired portion. In addition, since the porous phase can be arranged in an arbitrary shape, it can be used as a design member. In addition, as an example of applications that can be used by patterning a porous phase in a louver shape as shown in the figure, an optical sheet or a viewing angle control sheet that exhibits a brightness enhancement effect when incorporated in a backlight unit of a liquid crystal display In particular, it is suitably used in the field of optical functional elements.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not necessarily limited to these. Various characteristics were measured and evaluated as follows.

(Evaluation methods)
Lamination ratio, aspect ratio After cutting out the film cross section and depositing platinum-palladium, a photograph was taken at 400 times using a scanning electron microscope S-2100A manufactured by Hitachi, Ltd., and the cross section was observed. The aspect ratio was measured.

Example 1
100 parts by weight of polyester resin ("ELITEL" UE3600: manufactured by Unitika Ltd.) and 100 parts by weight of photosensitive monomer ("Light Ester" EG: manufactured by Kyoeisha Chemical Co., Ltd.), photosensitive monomer ("Light Ester" DE: Kyoeisha) Chemical Co., Ltd.) 25 parts by weight, photopolymerization initiator ("Irgacure" 651: Ciba Specialty Chemicals Co., Ltd.) 1.7 parts by weight, and photopolymerization initiator ("Irgacure" 819: Ciba Specialty) -0.8 part by weight of Chemicals Co., Ltd. was dissolved in 100 parts by weight of a methyl ethyl ketone / cyclohexanone mixed solvent (1/1, weight ratio). This solution was applied onto a 100 μm thick polyethylene terephthalate film (“Lumirror” 100 T60: manufactured by Toray Industries, Inc.) using a spin coater, dried at 80 ° C. for 15 minutes, cooled, and then cooled to 100 μm in thickness. A polyethylene terephthalate film (“Lumirror” 100 QT10: manufactured by Toray Industries, Inc.) was attached as a cover film to obtain a resin sheet having a coating thickness of 100 μm.

A photomask having a stripe pattern with a pitch of 100 μm and a width of 50 μm was placed on this transparent sheet at room temperature, irradiated with 100 mJ / cm ² using an ultrahigh pressure mercury lamp, heated at 85 ° C. for 2 minutes, and allowed to cool to room temperature. Remove the cover film, immerse it in methanol for 4 hours, take it out of the methanol, and use the ultra high pressure mercury lamp as it is, irradiate the coating film side and the substrate film side on both sides with 1000 mJ / cm ² , and leave it overnight at room temperature. Methanol was volatilized.

  When the cross section of the obtained coating film was observed with a scanning electron microscope, the pattern exposed portion had a 50 μm transparent phase, the pattern unexposed portion had a 50 μm porous phase alternately arranged, and the transparent phase had an aspect ratio of 2 It was confirmed that an optical pattern was formed.

(Example 2)
Composition is 100 parts by weight of a polyester resin ("ELITEL" UE3600: manufactured by Unitika Ltd.), 80 parts by weight of a photosensitive monomer ("Light Ester" EG: manufactured by Kyoeisha Chemical Co., Ltd.), and a photosensitive monomer ("Light Ester" DE). : Kyoeisha Chemical Co., Ltd.) 25 parts by weight, acrylic monomer ("KAYARAD" DPCA-30: Nippon Kayaku Co., Ltd.) 10 parts by weight, photopolymerization initiator ("Irgacure" 651: Ciba Specialty Chemicals ( A resin sheet was obtained in the same manner as in Example 1 except that it was 1.7 parts by weight, and 0.8 parts by weight of a photopolymerization initiator (“Irgacure” 819: Ciba Specialty Chemicals). It was. The coating thickness of this resin sheet was 100 μm, and it was transparent at room temperature as in Example 1.

  A stripe pattern was formed by the same operation as in Example 1, and the cross section of the obtained coating film was observed with a scanning electron microscope. As a result, the pattern exposed part was a 50 μm transparent phase, and the pattern unexposed part was a 50 μm porous phase. It was confirmed that an optical pattern having a transparent phase and an aspect ratio of 2.0 could be formed.

(Example 3)
Composition is 100 parts by weight of polyester resin ("ELITEL" UE3600: manufactured by Unitika Ltd.), 90 parts by weight of photosensitive monomer ("Light Ester" EG: manufactured by Kyoeisha Chemical Co., Ltd.), photosensitive monomer ("Light Ester" HOB) : Kyoeisha Chemical Co., Ltd.) 25 parts by weight, photosensitive monomer (“KAYARAD” DPCA-30: Nippon Kayaku Co., Ltd.) 10 parts by weight, photosensitive monomer (“Neomer” BA-641: Sanyo Kasei Co., Ltd. )) 10 parts by weight, photopolymerization initiator ("Irgacure" 651: Ciba Specialty Chemicals) 1.7 parts by weight, and photopolymerization initiator ("Irgacure" 819: Ciba Specialty Chemicals ( A resin sheet was obtained in the same manner as in Example 1 except that the amount was 0.8 parts by weight. The coating thickness of this resin sheet was 100 μm, and it was transparent at room temperature as in Example 1.

  A stripe pattern was formed by the same operation as in Example 1, and the cross section of the obtained coating film was sliced thinly and observed with an optical microscope. As a result, the pattern exposed part was a transparent phase of 50 μm, and the pattern unexposed part was a porous part of 50 μm. It was confirmed that an optical pattern in which the mass phases were alternately arranged and the aspect ratio of the transparent phase was 2.0 was formed.

Example 4
Composition is 100 parts by weight of polyester resin ("ELITEL" UE3600: manufactured by Unitika Ltd.), 50 parts by weight of photosensitive monomer ("Light Ester" EG: manufactured by Kyoeisha Chemical Co., Ltd.), photosensitive monomer ("Light Ester" DE) : Kyoeisha Chemical Co., Ltd.) 20 parts by weight, photopolymerization initiator ("Irgacure" 651: Ciba Specialty Chemicals Co., Ltd.) 0.09 parts by weight, and photopolymerization initiator ("Irgacure" 819: Ciba (Specialty Chemicals Co., Ltd.) A resin sheet was obtained in the same manner as in Example 1 except that the amount was changed to 0.045 parts by weight. The coating thickness of this resin sheet was 100 μm, and it was transparent at room temperature as in Example 1.

  A stripe pattern was formed by the same operation as in Example 1, and the cross section of the obtained coating film was sliced thinly and observed with an optical microscope. As a result, the pattern exposed part was a transparent phase of 50 μm, and the pattern unexposed part was a porous part of 50 μm. It was confirmed that an optical pattern in which the mass phases were alternately arranged and the aspect ratio of the transparent phase was 2.0 was formed.

(Example 5)
Composition is 100 parts by weight of a polyester resin ("ELITEL" UE3600: manufactured by Unitika Ltd.), 180 parts by weight of a photosensitive monomer ("Light Ester" EG: manufactured by Kyoeisha Chemical Co., Ltd.), and a photosensitive monomer ("Light Ester" DE). : Kyoeisha Chemical Co., Ltd.) 45 parts by weight, photopolymerization initiator ("Irgacure" 651: Ciba Specialty Chemicals Co., Ltd.) 3.0 parts by weight, and photopolymerization initiator ("Irgacure" 819: Ciba (Specialty Chemicals Co., Ltd.) A resin sheet was obtained in the same manner as in Example 1 except that the amount was 1.5 parts by weight. The coating thickness of this resin sheet was 100 μm, and it was transparent at room temperature as in Example 1.

  A stripe pattern was formed by the same operation as in Example 1, and the cross section of the obtained coating film was sliced thinly and observed with an optical microscope. As a result, the pattern exposed part was a transparent phase of 50 μm, and the pattern unexposed part was a porous part of 50 μm. It was confirmed that an optical pattern in which the mass phases were alternately arranged and the aspect ratio of the transparent phase was 2.0 was formed.

(Comparative Example 1)
Composition is 100 parts by weight of polyester resin ("ELITEL" UE3600: manufactured by Unitika Ltd.), 10 parts by weight of photosensitive monomer ("Light Ester" EG: manufactured by Kyoeisha Chemical Co., Ltd.), photosensitive monomer ("Light Ester" DE) : Kyoeisha Chemical Co., Ltd.) 2.5 parts by weight, photopolymerization initiator ("Irgacure" 651: Ciba Specialty Chemicals Co., Ltd.) 0.17 parts by weight, and photopolymerization initiator ("Irgacure" 819) : Ciba Specialty Chemicals Co., Ltd.) A resin sheet was obtained in the same manner as in Example 1 except that the amount was 0.08 part by weight. The coating thickness of this resin sheet was 100 μm, and it was transparent at room temperature as in Example 1.

  An attempt was made to form a stripe pattern by the same operation as in Example 1, but it did not penetrate even when immersed in methanol, and the formation of a porous phase was observed even when the cross section of the obtained coating film was observed with a scanning electron microscope. Was not confirmed.

(Comparative Example 2)
Composition is 100 parts by weight of a polyester resin ("ELITEL" UE3600: manufactured by Unitika Ltd.), 700 parts by weight of a photosensitive monomer ("Light Ester" EG: manufactured by Kyoeisha Chemical Co., Ltd.), and a photosensitive monomer ("Light Ester" DE). : Kyoeisha Chemical Co., Ltd.) 175 parts by weight, photopolymerization initiator ("Irgacure" 651: Ciba Specialty Chemicals Co., Ltd.) 11.7 parts by weight, and photopolymerization initiator ("Irgacure" 819: Ciba A resin sheet was obtained in the same manner as in Example 1 except that the amount was 5.8 parts by weight (made by Specialty Chemicals). The coating thickness of this resin sheet was 100 μm, and it was transparent at room temperature as in Example 1.

  An attempt was made to form a stripe pattern by the same operation as in Example 1. Even when the cross section of the obtained coating film was observed with a scanning electron microscope, the formation of a porous structure in the pattern unexposed part was confirmed, but a porous structure was also generated in the cured part, and the transparency of the cured part was poor. .

(A)-(g) is a cross-sectional view of the porous pattern of this invention, respectively, and illustrates typically the shape of the porous phase 1 in a cross section. (A), (b) is a perspective view which shows typically a part of porous pattern of this invention, respectively. (A)-(d) is sectional drawing in a cross section parallel to the sheet | seat surface of the porous pattern of this invention, respectively, and illustrates the shape of the transparent phase 2 typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-diffusion phase 2 Transparent phase L The length of a transparent phase p The short axis length of a transparent phase t The length of a porous phase

Claims (4)

A composition comprising at least three of a binder resin, a photosensitive compound and a photopolymerization initiator,
The binder resin is a polyester resin, the photosensitive compound is a compound having a (meth) acryloyl group, and the photosensitive compound is compatible with the binder resin and dissolved in a poor solvent of the binder resin. Is a compound that does not substantially form voids even when immersed in a poor solvent of the binder resin after curing by electromagnetic wave irradiation,
And the ratio which occupies for the total solid of this photosensitive compound is 30 to 80 weight%, The photopolymerizable composition for porous pattern formation characterized by the above-mentioned.
A method for producing a resin sheet having a porous pattern having a structure in which a porous phase composed of continuous pores and a transparent phase substantially free of voids are alternately arranged,
It consists of at least three of a binder resin, a photosensitive compound and a photopolymerization initiator, the binder resin is a polyester resin, the photosensitive compound is a compound having a (meth) acryloyl group, and the total solid content of the photosensitive compound After forming a coating film by coating a composition having a proportion of 30 to 80% by weight on a substrate,
The coating film is irradiated with electromagnetic waves according to a desired pattern, and the irradiated part is cured,
Then, after immersing in a poor solvent for the binder resin to extract the photosensitive compound of the uncured part,
A method for producing a resin sheet having a porous pattern, wherein the non-irradiated site is made porous by volatilizing the poor solvent that has penetrated into the coating film.
A method for producing a resin sheet having a porous pattern according to claim 2 ,
A resin having a porous pattern comprising a step of irradiating the entire surface with electromagnetic waves while the uncured portion of the coating film remains in a state containing the solvent after being immersed in the poor solvent Sheet manufacturing method.
Obtained by the production method of the resin sheet having a porous pattern according to claim 2 or 3, a porous phase consisting of continuous pores, and a transparent phase that is substantially free of voids inside are arranged alternately A resin sheet having a porous pattern, characterized by comprising a structure.

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