JP2011242664A - Photosensitive composition for barrier rib formation, method of forming barrier rib for electronic paper, barrier rib for electronic paper and electronic paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive composition for barrier rib formation capable of forming a barrier rib which can maintain the rectangular shape when heated, a method of forming a barrier rib for electronic paper with the use of the photosensitive composition for barrier rib formation, a barrier rib for electronic paper, and electronic paper having the barrier rib for electronic paper.SOLUTION: The photosensitive composition for barrier rib formation is used for forming a barrier rib for electronic paper and contains the following (A) to (D) constituents: (A) constituent: a polymer which has a structural unit having a phenolic hydroxyl group (a1) and a structural unit having an alicyclic hydrocarbon group (a2); (B) constituent: a polyfunctional monomer; (C) constituent: a photosensitive polymerization initiator; and (D) constituent: an organic solvent.

Description

  The present invention relates to a photosensitive composition for forming a partition, a method for forming a partition for electronic paper, a partition for electronic paper, and electronic paper. More specifically, a barrier rib forming photosensitive composition used for forming barrier ribs in electronic paper, a method of forming barrier ribs for electronic paper using the barrier rib forming photosensitive composition, a barrier for electronic paper, and the electronic paper The present invention relates to an electronic paper having a partition wall.

  A paper-like display medium that has the advantages of both a display and a paper medium as an information display device, is thin, lightweight, rewritable, maintains display even when power is not supplied, and is suitable for the act of reading The need for is increasing. This is generally called electronic paper, and various methods have been proposed and researched and developed. In particular, the electrophoresis method is considered to be used for electronic devices such as mobile phones because it is easy to reduce power consumption, thin, flexible, and memory.

A display element (electrophoretic display element) using an electrophoretic method basically includes a pair of electrodes opposed to each other, and a partition is provided between the electrodes to form a plurality of cells, and each cell includes an electrophoretic particle. It contains a particle-containing liquid.
As a method of forming partition walls used in an electrophoretic display element, a method of forming a partition by a lithographic method using a photosensitive composition is known. For example, a method for forming a partition using a photosensitive composition having an epoxy acrylate prepolymer or a photosensitive composition having urethane acrylate is known (Patent Document 1). Moreover, the formation method of the partition using the photosensitive composition which has a polyfunctional monomer which has an isocyanuric ring structure is known (patent document 2).

WO2007 / 013682 Publication Japanese Patent No. 2010-66676

When manufacturing an electrophoretic display element, it is necessary to enclose an electrophoretic particle-containing liquid in a cell and attach and seal a pair of electrodes and a partition provided between the electrodes. The electrode and the partition are bonded together by applying heat (200 to 250 ° C.) using an adhesive, so that the aspect ratio used for an electrophoretic display element or the like (the partition height with respect to the partition width) In the case of a large partition wall, there is a problem that the shape of the partition wall cannot be maintained at the time of bonding.
The present invention has been made to solve the above-described problems. That is, the barrier rib-forming photosensitive composition capable of forming a barrier rib that can maintain a rectangular shape when heated, and the barrier rib-forming photosensitive composition are used. It is an object of the present invention to provide an electronic paper partition forming method, an electronic paper partition, and an electronic paper having the electronic paper partition.

The present invention is as follows.
<1> A photosensitive composition for forming a partition, which is used for forming a partition for electronic paper and contains the following components (A) to (D).
(A) Component: A polymer having a structural unit (a1) having a phenolic hydroxyl group and a structural unit (a2) having an alicyclic hydrocarbon group.
(B) component: a polyfunctional monomer.
Component (C): photosensitive polymerization initiator.
Component (D): an organic solvent.
<2> When the total structural unit in the polymer (A) is 100% by mass, the content of the structural unit (a1) is 1 to 40% by mass. Composition.
<3> When the total structural unit in the polymer (A) is 100% by mass, the content of the structural unit (a2) is 10 to 80% by mass in either <1> or <2> The photosensitive composition for barrier rib formation of description.
<4> A method for forming an electronic paper partition comprising the following steps (1) to (3).
Process (1): The process of forming the coating film obtained from the photosensitive composition for barrier rib formation in any one of said <1> thru | or <3> on a board | substrate.
Step (2): A step of exposing the coating film obtained in step (1) so as to correspond to the partition walls.
Process (3): The process of developing the coating film after exposure obtained at the process (2).
<5> A partition for electronic paper obtained by the method for forming a partition for electronic paper according to <4>.
<6> A partition for electronic paper having a structure derived from a phenolic hydroxyl group and an alicyclic hydrocarbon group.
<7> A plurality of cells each including the partition for electronic paper according to any one of <5> and <6>, a pair of electrode substrates facing each other through the partition, and the partition and the electrode substrate And an electronic paper having at least a charged particle component contained in the cell.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive composition for partition formation which can form the partition which can maintain a rectangle at the time of heating, the formation method of the partition for electronic paper which can maintain a rectangle at the time of heating, the electronic paper which can maintain a rectangle at the time of heating An electronic paper having a partition wall and the electronic paper partition wall can be provided.

It is the figure which showed typically "the formation method of the partition for electronic paper" of this invention. It is the perspective view which showed typically the board | substrate which has the "partition for electronic paper" of this invention.

  Hereinafter, the photosensitive composition for partition formation according to the present invention, the method for forming the partition for electronic paper, the partition for electronic paper, and the electronic paper will be described in detail.

[1] Photosensitive composition for forming barrier ribs The photosensitive composition for forming barrier ribs of the present invention is used for forming barrier ribs for electronic paper and contains the following components (A) to (D). And

(A) Component: A polymer having a structural unit (a1) having a phenolic hydroxyl group and a structural unit (a2) having an alicyclic hydrocarbon group.
(B) component: a polyfunctional monomer.
Component (C): photosensitive polymerization initiator.
Component (D): an organic solvent.

  The “electronic paper” in the present invention can be electronically displayed on a paper-like thin display medium, and among these, a display medium on which writing (excluding organic EL) is performed by electricity and magnetism. . Examples of display media on which writing is performed by electricity and magnetism include, for example, twist ball method, electrophoresis method, magnetophoresis method, electro-powder fluid method, charged toner type display method, liquid crystal display method, electrolytic deposition method, electrochromic method, There are a film movement method and an interference control method. In addition, the “electronic paper partition wall” in the present invention refers to a wall used for partitioning adjacent cells or pixels in the electronic paper.

  The “photosensitive composition” in the present invention is a composition used in photolithography, whose physical properties such as solubility are changed by light, electron beam or the like. It is a composition that has photosensitivity and that can be patterned by imagewise exposure and development to form an image layer.

[1-1] Component (A): Polymer The polymer of component (A) has a structural unit (a1) having a phenolic hydroxyl group and a structural unit (a2) having an alicyclic hydrocarbon group. And
When a partition having a large aspect ratio used for electronic paper is formed with the photosensitive composition for forming a partition, light transmitted through a coating film (hereinafter, also referred to as “coating film”) obtained from the photosensitive composition for forming a partition. When the rate is low, the exposure amount in the vicinity of the substrate of the coating film becomes smaller than the exposure amount in the vicinity of the surface of the coating film. Usually, the amount of active species derived from the photosensitive polymerization initiator generated in the coating film is proportional to the exposure amount, so the amount of active species generated near the substrate of the coating film is smaller than that near the surface of the coating film. As a result, a reverse-tapered partition is formed.

  On the other hand, if a coating film with high light transmittance is used, an antireflection film cannot be formed on the substrate. Therefore, the light reaching the substrate surface is reflected or diffracted on the substrate surface, and reflected light or diffraction Light is generated. For this reason, in the coating film with high transmittance, the exposure amount increases in the vicinity of the substrate of the coating film due to reflected light or diffracted light. For this reason, since the exposure amount in the vicinity of the substrate and the surface of the coating film increases, the amount of active species generated in the vicinity of the substrate and the surface of the coating film increases, and as a result, a skirt-like partition is formed.

The present invention has a function of deactivating active species of a phenolic hydroxyl group, a function of increasing transparency of a coating film of an alicyclic hydrocarbon group to light, and a synergistic effect of the phenolic hydroxyl group and an alicyclic hydrocarbon group. The focus is on the improvement of heat resistance.
That is, since the polymer (A) has the structural unit (a2) having an alicyclic hydrocarbon group, the light transmittance of the coating film can be increased, and exposure of the coating film near the substrate and near the surface is performed. The amount increases. However, since the coating film having the polymer (A) having the structural unit (a1) having a phenolic hydroxyl group has a function of deactivating active species, the activity is proportional to the amount of generated active species. The seed is deactivated. For this reason, the active species generated more in the vicinity of the surface of the coating film and in the vicinity of the substrate of the coating film are deactivated by the exposure. As a result, the amount of active species is uniform in the thickness direction of the coating film, and as a result, rectangular partition walls are formed.

  Furthermore, it is known that the polymer (A) having a structural unit having a phenolic hydroxyl group and the polymer having an alicyclic hydrocarbon group are each excellent in heat resistance. By having the structural unit, it becomes more excellent in heat resistance. For the above-mentioned reason, the partition obtained from the photosensitive composition for partition formation containing the polymer (A) which has the structural unit (a1) which has a structural unit (a1) which has a phenolic hydroxyl group, and an alicyclic hydrocarbon group. Becomes a partition which can maintain a rectangle during heating.

  In addition, as a method of forming a rectangular partition, for example, by selecting the solubility of the polymer contained in the partition-forming photosensitive composition in the developer, the type and amount of the photosensitive polymerization initiator, and additives. It is known to be possible. However, there is no known method for forming a rectangular partition, and further, as a partition for electronic paper, a partition that can maintain a rectangle during heating.

  When the content of the structural unit (a1) having a phenolic hydroxyl group contained in the polymer (A) is 100 parts by mass, the structural unit (a2 having an alicyclic hydrocarbon group contained in the polymer (A) ) Is preferably 25 to 8000 parts by mass, more preferably 60 to 6500 parts by mass, and still more preferably 90 to 5500 parts by mass. It is preferable for this content to be in the range of 25 to 8000 parts by mass because a partition wall that can maintain a rectangle during heating can be formed.

  The weight average molecular weight (Mw) in terms of polystyrene by gel permeation column chromatography of the polymer (A) is the type of monomer used to obtain the polymer (A), the polymerization formulation, and the glass of the polymer (A). Although it is appropriately selected depending on the transition temperature, it is usually Mw = 5000 to 20000, preferably Mw = 8000 to 12000.

  The content ratio of the polymer (A) used in the photosensitive composition for forming a partition wall of the present invention is appropriately selected depending on the height of the partition wall to be formed and the coating method, but is usually included in the photosensitive composition for partition wall formation. When all the components are 100% by mass, the content is 30 to 90% by mass.

  When all the components of the photosensitive composition for partition formation of this invention except a solvent (D) are 100 mass%, the content rate of a polymer (A) is 30-90 mass% normally. This is because, when the polymer (A) is used as the main component of the partition walls, partition walls that can maintain a rectangular shape when heated can be formed.

Structural unit having a phenolic hydroxyl group (a1)
The “phenolic hydroxyl group” refers to a hydroxyl group directly bonded to an aromatic ring such as a benzene ring or a naphthalene ring. The “structural unit” indicates a polymer structure in which one monomer is used for each monomer used in forming the polymer. This “structural unit having a phenolic hydroxyl group” is polymerized by using a monomer having a phenolic hydroxyl group (a1 ′) or by using a monomer having a group that can be converted to a phenolic hydroxyl group. Then, the structural unit (a1) which has a phenolic hydroxyl group can be introduce | transduced into the structure of a polymer (A) by converting into a phenolic hydroxyl group.

  The content ratio of the structural unit (a1) having the phenolic hydroxyl group is preferably 1 to 40% by mass, more preferably 5 to 30% by mass, when the total structural unit in the polymer (A) is 100% by mass. More preferably, it is 10-20 mass%. When the content rate of the structural unit (a1) which has a phenolic hydroxyl group is 1-40 mass%, the photosensitive composition for partition formation excellent in the resolution can be obtained.

  Examples of the method for introducing the “structural unit (a1) having a phenolic hydroxyl group” obtained by polymerization using the monomer (a1 ′) having a phenolic hydroxyl group into the polymer (A) include phenol and naphthol. Such as condensation polymerization of phenols such as aldehydes and condensing agents such as aldehydes, radical polymerization or cationic polymerization of monomers having a polymerizable group such as a (meth) acrylic group or vinyl group and a phenolic hydroxyl group The method etc. which are introduce | transduced by etc. are mentioned. Among these, a monomer having a vinyl group and a phenolic hydroxyl group from the viewpoint of easily copolymerizing with a monomer having an alicyclic hydrocarbon group, which will be described later, and from being easy to form a partition that can maintain a rectangular shape when heated. Is preferably introduced by radical polymerization.

  Examples of the monomer having a vinyl group and a phenolic hydroxyl group include p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, α-methyl-p-hydroxystyrene, α-methyl-m-hydroxystyrene, α Examples thereof include monomers represented by the following formula (1) such as -methyl-o-hydroxystyrene.

（式（１）中、Ｒ^１は水素原子又はメチル基を示す）

(In formula (1), R ¹ represents a hydrogen atom or a methyl group)

  When radical polymerization is performed using the monomer represented by the formula (1), the polymer has a structural unit represented by the following formula (2).

（式（２）中、Ｒ^２は水素原子又はメチル基を示す）

(In formula (2), R ² represents a hydrogen atom or a methyl group)

  Only one type of monomer may be used, or two or more types may be used. In addition, the radical polymerization method can be obtained by a conventional method such as a method described in JP 2009-162613 A or JP 2009-163080 A.

Structural unit having an alicyclic hydrocarbon group (a2)
The “alicyclic hydrocarbon group” refers to a group composed of only carbon and hydrogen, wherein the carbon atom excluding the aromatic group has a cyclic structure (including a polycyclic structure). The “structural unit” indicates a polymer structure in which one monomer is used for each monomer used in forming the polymer. This “structural unit having a phenolic hydroxyl group” is obtained by polymerizing using a monomer (a2 ′) having an alicyclic hydrocarbon group to thereby superimpose the structural unit (a2) having an alicyclic hydrocarbon group. It can be introduced into the coalescence (A).

  The content of the structural unit (a2) having the alicyclic hydrocarbon group is usually 10 to 80% by mass from the viewpoint of transmittance when the total structural unit in the polymer (A) is 100% by mass. More preferably, it is 30-50 mass%.

  As a method for introducing the “structural unit (a2) having an alicyclic hydrocarbon group” obtained by polymerization using a monomer (a2 ′) having an alicyclic hydrocarbon group into the polymer (A). And a method of introducing a monomer having a polymerizable group such as a (meth) acryl group or a vinyl group and an alicyclic hydrocarbon group by radical polymerization or cationic polymerization. Among these, from the point that it is easy to obtain a copolymer with the monomer having the phenolic hydroxyl group, and the point that it is easy to form a partition that can maintain a rectangle during heating, (meth) acryl group and alicyclic hydrocarbon group A method of introducing a monomer having a radical by radical polymerization is preferred.

  Examples of the monomer having a (meth) acryl group and an alicyclic hydrocarbon group include those described in JP-A-2008-233346, JP-A-2009-162613, and JP-A-2009-163080. The monomer and the monomer shown by following formula (3) can be mentioned.

（式（３）中、Ｒ^３は水素原子又はメチル基を示す。Ｒ^４は炭素数７〜３０の炭素原子および水素原子のみからなる脂環式炭化水素基である。）

(In Formula (3), R ³ represents a hydrogen atom or a methyl group. R ⁴ is an alicyclic hydrocarbon group composed of only a carbon atom having 7 to 30 carbon atoms and a hydrogen atom.)

Examples of the monomer having the structure represented by the formula (3) include tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decane. -8-yloxyethyl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yloxyethyl acrylate, Examples thereof include cyclohexyl acrylate, 2-methylcyclohexyl acrylate, isobornyl acrylate, and tetrahydrofurfuryl methacrylate. Among these, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate and isoboronyl acrylate are preferable because they can easily form a partition that can maintain a rectangular shape when heated.

  When radical polymerization is performed using the monomer represented by the formula (3), the polymer has a structural unit represented by the following formula (4).

（式（４）中、Ｒ^５は水素原子又はメチル基を示す。Ｒ^６は炭素数７〜３０の炭素原子および水素原子のみからなる脂環式炭化水素基である。）

(In Formula (4), R ⁵ represents a hydrogen atom or a methyl group. R ⁶ is an alicyclic hydrocarbon group consisting of only a carbon atom having 7 to 30 carbon atoms and a hydrogen atom.)

  These monomers may be used alone or in combination of two or more. By using two or more monomers in combination, a monomer that is difficult to undergo radical polymerization can be introduced into the polymer. In addition, the radical polymerization method can be obtained by a conventional method such as a method described in JP 2009-162613 A or JP 2009-163080 A.

Other structural units (a3)
The polymer (A) of the present invention can contain other structural units (a3) as long as the effect of forming a partition that can maintain a rectangular shape during heating is not impaired. Other structural units include a structural unit having a polyalkylene glycol group used for the purpose of improving adhesion to the substrate, and a structural unit having a carboxyl group for the purpose of adjusting the solubility of the polymer (A) in the developer. Etc.

  The structural unit having the polyalkylene glycol group is not particularly limited as long as it has a polyalkylene glycol group, but the monomer having a phenolic hydroxyl group represented by the formula (1) or the formula (3) When using a monomer having an alicyclic hydrocarbon group, the monomer having a polymerizable group and a polyalkylene glycol group is usually radically polymerized and introduced into the polymer.

  Examples of the monomer having a polymerizable group and a polyalkylene glycol group include monomers described in JP-A-2008-273820 and JP-A-2009-192613, and monomers represented by the following formula (5). Can be mentioned.

（式（５）中、Ｒ^７は水素原子又はメチル基を示す。Ｒ^８はメチレン基又は炭素数２乃至４のアルキレン基を示す。Ｒ^９は炭素数６〜１２の直鎖状、環状もしくは芳香族の炭化水素基、またはこれらの基の少なくとも１つの水素原子が炭化水素基に置換された置換炭化水素基を示す。ｍは１〜１０の整数を示す。）

(In Formula (5), R ⁷ represents a hydrogen atom or a methyl group. R ⁸ represents a methylene group or an alkylene group having 2 to 4 carbon atoms. R ⁹ is a straight chain, cyclic or cyclic group having 6 to 12 carbon atoms. An aromatic hydrocarbon group, or a substituted hydrocarbon group in which at least one hydrogen atom of these groups is substituted with a hydrocarbon group, m represents an integer of 1 to 10.)

  As the monomer having the structure represented by the formula (5), phenoxydiethylene glycol (meth) acrylate, phenoxytriethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, phenoxydipropylene glycol (meth) acrylate, phenoxy Tripropylene glycol (meth) acrylate, Phenoxytetrapropylene glycol (meth) acrylate, Lauroxydiethylene glycol (meth) acrylate, Lauroxytriethylene glycol (meth) acrylate, Lauroxytetraethylene glycol (meth) acrylate, Lauroxydipropylene glycol ( (Meth) acrylate, lauroxytripropylene glycol (meth) acrylate, lauroxytetrapropi Such as glycol (meth) acrylate.

  When radical polymerization is performed using the monomer represented by the formula (5), a structural unit represented by the following formula (6) can be obtained.

（式（６）中、Ｒ^１０は水素原子又はメチル基を示す。Ｒ^１１はメチレン基又は炭素数２乃至４のアルキレン基を示す。Ｒ^１２は炭素数６〜１２の直鎖状、環状もしくは芳香族の炭化水素基、またはこれらの基の少なくとも１つの水素原子が炭化水素基に置換された置換炭化水素基を示す。ｎは１〜１０の整数を示す。）

(In the formula (6), R ¹⁰ represents a hydrogen atom or a methyl group. R ¹¹ represents a methylene group or an alkylene group having 2 to 4 carbon atoms. R ¹² represents a linear, cyclic or cyclic group having 6 to 12 carbon atoms. An aromatic hydrocarbon group or a substituted hydrocarbon group in which at least one hydrogen atom of these groups is substituted with a hydrocarbon group, n represents an integer of 1 to 10.)

  The structural unit having a carboxyl group is not particularly limited as long as it has a carboxyl group, but a monomer having a phenolic hydroxyl group represented by the formula (1) or an alicyclic carbonization represented by the formula (3). When using a monomer having a hydrogen group, a monomer having a polymerizable group and a carboxyl group is usually radically polymerized and introduced into the polymer.

  Examples of the monomer having a polymerizable group and a carboxyl group include methacrylic acid and acrylic acid.

  As the other structural unit (a3), in addition to the structural unit having a polyalkylene glycol group and the structural unit having a carboxyl group, those described in JP-A-2009-162613, JP-A-2009-163080, etc. It can have a structural unit derived from a monomer.

[1-2] Component (B): Multifunctional monomer The polyfunctional monomer of component (B) is a monomer having at least two polymerizable unsaturated bond groups. is there. The polyfunctional monomer (B) is a component that can act on the active species generated from the photosensitive polymerization initiator of the component (C) by the action of light to initiate polymerization and form a three-dimensionally crosslinked structure. It is. Thereby, in the coating film obtained from the photosensitive composition for barrier rib formation, the part which exposed light becomes difficult to melt | dissolve with respect to a developing solution.

  The content of the multifunctional monomer (B) used in the barrier rib-forming photosensitive composition of the present invention is appropriately selected depending on the sensitivity and resolution in the method for forming barrier ribs for electronic paper, but the polymer (A) When the content of is 100 parts by mass, the content of the polyfunctional monomer (B) is usually used in the range of 1 to 100 parts by mass.

  Examples of the polyfunctional monomer (B) include polyfunctional monomers described in JP-A-2006-285035 and JP-A-2009-192613. Specifically, di (meth) acrylates of alkylene glycol such as ethylene glycol and propylene glycol; di (meth) acrylates of polyalkylene glycol such as polyethylene glycol and polypropylene glycol; glycerin, trimethylolpropane, pentaerythritol, di Poly (meth) acrylates of trihydric or higher polyhydric alcohols such as pentaerythritol and their dicarboxylic acid-modified products; oligo (meth) acrylates such as polyester, epoxy resin, urethane resin, alkyd resin, silicone resin, and spirane resin Di (meth) acrylates of both terminal hydroxylated polymers such as both terminal hydroxypoly-1,3-butadiene, both terminal hydroxypolyisoprene and both terminal hydroxypolycaprolactone; - (meth) acryloyloxyethyl] phosphate, and the like can be mentioned.

  Among these polyfunctional monomers, poly (meth) acrylates of trihydric or higher polyhydric alcohols and their dicarboxylic acid modified products, specifically, trimethylolpropane tri (meth) acrylate, pentaerythritol tris. (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. are preferred, especially trimethylolpropane triacrylate, pentaerythritol triacrylate and dipentaerythritol. Hexaacrylate is preferable because it can form a partition that can maintain a rectangular shape when heated.

[1-3] Component (C): Photosensitive polymerization initiator The photosensitive polymerization initiator of component (C) is a semiconductor laser, a metal halide lamp, a high-pressure mercury lamp (g-line, h-line, i-line, etc.), excimer laser. It is a compound that can generate active species capable of initiating polymerization of the polyfunctional monomer (B) by exposure light such as extreme ultraviolet rays and electron beams.

  The content of the photosensitive polymerization initiator (C) used in the barrier rib-forming photosensitive composition of the present invention is appropriately selected depending on the sensitivity and resolution with respect to exposure light in the method for forming barrier ribs for electronic paper. When content of A) is 100 parts by mass, the content of the photosensitive polymerization initiator (C) is usually used within a range of 1 to 50 parts by mass.

  Examples of the photosensitive polymerization initiator (C) include photosensitive polymerization initiators described in JP-A-2006-285035 and JP-A-2009-192613. Specifically, acylphosphine oxide compounds, biimidazole compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, xanthone compounds, triazine compounds, O-acyloxy And the like. These may use only 1 type and may use 2 or more types together. In particular, as the photosensitive polymerization initiator (C) in the present invention, when a high-pressure mercury lamp containing g-line, h-line and i-line is used as exposure light, it is possible to form a rectangular partition with good sensitivity. A combination of an acylphosphine oxide compound and an acetophenone compound is preferable.

  Acylphosphine oxide compounds include bis (2,6-dichlorobenzoyl) -phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dioxy). Chlorobenzoyl) -4-ethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2-naphthylphosphine oxide, bis (2, 6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-chlorophenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,4-dimethoxyphenylphosphine oxide , Screw (2,6-dic Rubenzoyl) -decylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-octylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethyl) Benzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichloro-3,4,5-trimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichloro-3, 4,5-trimethoxybenzoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-ethoxy Phenylphosphine oxide, bis (2-mes 1-naphthoyl) -2-naphthylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-propylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide Bis (2-methoxy-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2-chloro-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2 4,4-trimethylpentylphosphine oxide and the like.

  Examples of acetophenone compounds include 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, -(4-Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 4- (2-hydroxy Ethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2,2- Examples include dimethoxy-1,2-diphenylethane-1-one.

[1-4] Component (D): Organic solvent The organic solvent (D) component can uniformly dissolve other components other than the organic solvent (D) contained in the barrier rib-forming photosensitive composition. And if it is a compound which does not react with these other components, it will not be limited.

  Content of the organic solvent (D) contained in the photosensitive composition for partition formation of this invention can be suitably determined according to the coating method, the height of a partition, etc.

  Examples of the organic solvent (D) include alcohols such as ethylene glycol; cyclic ethers such as tetrahydrofuran; alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether; alkyl ethers of polyhydric alcohols such as propylene glycol monomethyl ether acetate. Acetates; Aromatic hydrocarbons such as toluene; Ketones such as methyl ethyl ketone; Esters such as ethyl acetate. These organic solvents may use only 1 type and may use 2 or more types together.

  Also, N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, benzylethyl ether, dihexyl ether, acetonylacetone , Isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, phenyl cellosolve acetate, etc. High boiling organic solvents can also be used.

[1-5] Other components In the photosensitive composition for forming a partition wall of the present invention, if necessary, a thermal polymerization inhibitor, a surfactant, an adhesion assistant, a solubility adjuster, a colorant, conductive particles, A viscosity modifier or the like can be used.

  During the storage of the photosensitive composition for forming a partition wall of the present invention, the thermal polymerization inhibitor causes the photosensitive polymerization initiator (C) to generate an active species by heat, and to the polyfunctional monomer (B). It is a component used to prevent the action. Examples of the thermal polymerization inhibitor include pyrogallol, benzoquinone, hydroquinone, monobenzyl ether, methylhydroquinone, amylquinone, amyloxyhydroquinone and the like.

  The surfactant is a component used for improving the coating property, defoaming property, and leveling property when applied to the substrate of the photosensitive composition for forming a partition wall of the present invention. As a surfactant, for example, commercially available FTX-204D, FTX-208D, FTX-212D, FTX-216D, FTX-218, FTX-220D, FTX-222D (manufactured by Neos Co., Ltd.), BM-1000, BM-1100 (above, manufactured by BM Chemie), MegaFuck F142D, F172, F173, F183 (above, manufactured by Dainippon Ink and Chemicals), Florard FC-135, FC- 170C, FC-430, FC-431 (above, manufactured by Sumitomo 3M), Surflon S-112, S-113, S-131, S-141, S-145 (above, Asahi Glass) Manufactured by Co., Ltd.), SH-28PA, -190, -193, SZ-6032, SF-8428 (above, Toray Dow Corning Silicone) Co., Ltd.)), and the like.

  The adhesion assistant is a component used for improving the adhesion between the partition walls and the substrate. As the adhesion assistant, a functional silane coupling agent is preferable. In addition, a functional silane coupling agent means the silane coupling agent which has reactive substituents, such as a carboxyl group, a methacryloyl group, an isocyanate group, and an epoxy group. Examples of the functional silane coupling agent include trimethoxysilylbenzoic acid, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, and γ-glycidoxypropyl. Examples include trimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

  A solubility regulator is a component used in order to adjust the solubility with respect to the developing solution of the coating film obtained from the photosensitive composition for partition formation of this invention. As the solubility adjuster, a low molecular carboxylic acid is preferable. Low molecular carboxylic acids include monocarboxylic acids such as acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid, iso-valeric acid, benzoic acid, cinnamic acid; lactic acid, 2-hydroxybutyric acid, 3 Hydroxy such as hydroxybutyric acid, salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, 4-hydroxycinnamic acid, 5-hydroxyisophthalic acid, syringic acid Monocarboxylic acid; oxalic acid, succinic acid, glutaric acid, adipic acid, maleic acid, itaconic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,2,4- Cyclohexanetricarboxylic acid, trimellitic acid, pyromellitic acid, cyclopentanetetracarboxylic acid, butante Polycarboxylic acids such as lacarboxylic acid, 1,2,5,8-naphthalenetetracarboxylic acid; itaconic anhydride, succinic anhydride, citraconic anhydride, dodecenyl succinic anhydride, tricarbanilic anhydride, maleic anhydride, hexahydrophthalic anhydride Acid, methyltetrahydrophthalic anhydride, hymic anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride Acid anhydrides such as benzophenone tetracarboxylic anhydride, ethylene glycol bis trimellitic anhydride, and glycerin tris anhydrous trimellitate.

  The colorant is a component used for the purpose of improving the contrast of the electronic paper. Examples of the colorant include pigments such as organic pigments and inorganic pigments, and dyes. Organic pigments are compounds classified as pigments in the Color Index (CI; issued by The Society of Dyers and Colorists), and inorganic pigments include titanium oxide, barium sulfate, calcium carbonate, zinc white, lead sulfate. Yellow lead, zinc yellow, red bean (red iron oxide (III)), cadmium red, ultramarine blue, bitumen, chromium oxide green, cobalt green, amber, titanium black, synthetic iron black, carbon black and the like.

  The conductive particles are components used for the purpose of imparting conductivity to the partition walls. Examples of the conductive particles include metals such as gold, silver, copper, aluminum, lead, and zinc, and metal compounds containing these metals.

  The viscosity modifier is used for the purpose of improving the coating property by adjusting the viscosity of the photosensitive composition for forming a partition wall of the present invention. Examples of the viscosity modifier include benite and silica gel.

[1-6] Preparation of barrier rib forming photosensitive composition The barrier rib forming photosensitive composition of the present invention uniformly mixes the components (A) to (D) and other components optionally added. It is prepared by. The barrier rib-forming photosensitive composition of the present invention is used, for example, in a solution state in which other components are dissolved in the appropriate organic solvent (component D). For example, the (A) component to the (C) component and other optional components are mixed with the organic solvent (D) at a predetermined ratio to prepare a solution-forming photosensitive composition for partition wall formation. be able to.

  When preparing the barrier rib-forming photosensitive composition in a solution state, components other than the organic solvent (D) in the solution (that is, the sum of the components (A) to (C) and other components optionally added) The amount (solid content concentration) can be arbitrarily set according to the purpose of use, the value of the desired film thickness, and the like.

[2] Method for forming partition for electronic paper As a method for forming partition for electronic paper, a photosensitive film obtained by forming a coating film obtained from the above-mentioned photosensitive composition for partition formation on a film support such as polyethylene terephthalate. There is a method of forming using an element, or a method according to the “method of forming a partition for electronic paper” of the present invention described later. Among these, the latter “method for forming a partition for electronic paper” of the present invention is preferred in that a rectangular partition can be obtained and a partition that can maintain a rectangle during heating can be formed.

The “method for forming a partition for electronic paper” of the present invention includes the following steps (1) to (3). Hereinafter, the details of each step will be described with reference to FIG. 1. Step (1): A coating obtained from “[1] photosensitive composition for forming a partition wall” (hereinafter also referred to as “composition”) on a substrate. A step of forming a film (hereinafter also referred to as “coating film”).
Step (2): A step of exposing the coating film obtained in step (1) so as to correspond to the partition walls.
Process (3): The process of developing the coating film after exposure obtained at the process (2).

[2-1] Step (1)
In step (1), as shown in FIG. 2 (a), a coating is formed by applying the composition on the substrate and removing the solvent by performing heat treatment (pre-baking) as necessary. It is a process.
Examples of the substrate include a glass substrate, a resin substrate, a semiconductor substrate such as silicon, or a substrate on which a transparent electrode such as ITO is formed.

As a method for applying the composition, any method can be used as long as the composition can be applied uniformly. For example, spraying, roll coating, spin coating (spin coating), slit die coating An appropriate method such as a method, a bar coating method, or an ink jet method can be employed. In particular, a spin coating method or a slit die coating method is preferable because a coating film having a uniform film thickness can be obtained.
The prebaking conditions can be appropriately selected depending on the components, particularly the type and amount of the solvent used, but are usually about 60 to 160 ° C. for about 30 seconds to 15 minutes.

  The film thickness of the coating film thus obtained is appropriately selected depending on the height of the target partition wall determined by various methods. Usually, the thickness of the coating film is the same as the height of the target partition wall. Alternatively, it is formed thick. For example, the film thickness of the coating film in the vertical electrophoresis system is usually 10 to 100 μm.

[2-2] Step (2)
In the step (2), as shown in FIG. 2B, the coating film obtained in the step (1) is passed through a patterned mask as necessary so as to correspond to the shape of the target partition wall. It is a step of forming a coating film (film after exposure) having a latent image by exposure.
Examples of the exposure light include semiconductor lasers, metal halide lamps, high-pressure mercury lamps (g-line, h-line, i-line, etc.), excimer lasers, extreme ultraviolet rays, and electron beams. A high-pressure mercury lamp is preferable because it has high transparency to the coating film and can form a pattern with high resolution.

The amount of exposure is appropriately selected depending on the type of exposure light, the film thickness and type of the coating film, and the shape of the target partition wall. In the case of a high-pressure mercury lamp, it is usually 100 to 1500 mJ / cm ² .

  Since the coating film obtained by the step (1) is a negative type, the exposed portion of the coating film is patterned. For this reason, it exposes to the said coating film through the patterning mask designed so that the location corresponding to the target partition may become higher in the transmittance | permeability with respect to exposure light than the other location. Further, the exposure method can be appropriately selected depending on the size of the target partition wall. When forming a fine partition wall, exposure is usually performed by a reduction projection method.

  After the exposure, heat treatment (hereinafter also referred to as “PEB”) may be performed as necessary. The conditions for PEB can be appropriately selected depending on the components, particularly the type and amount of the photosensitive polymerization initiator (C) contained in the composition, but usually at 60 to 160 ° C. for 30 seconds to 15 minutes. is there.

[2-3] Step (3)
In the step (3), as shown in FIG. 2 (c), the developer is brought into contact with the coating film after the exposure obtained in the step (2), thereby having relatively high solubility in the developer. It is a step of removing a portion to form a patterned coating film, that is, a step of developing a coating film having a latent image and patterning the latent image to form a patterned coating film.

  Examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, diethylaminoethanol, di-n-propylamine, triethylamine, methyl Diethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4. 3.0] An aqueous solution of a basic compound such as 5-nonane can be used. Further, an aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant to the aqueous solution of the basic compound can also be used as a developer. As a method for contacting the developer, for example, an appropriate method such as a liquid piling method, a dipping method, a rocking dipping method, a shower method, or the like can be used.

The patterned coating film obtained by contact with the developer is usually washed with water. Further, for the purpose of decomposing the photosensitive polymerization initiator (C) remaining in the patterned coating film and not decomposed by the exposure light, or a polyfunctional monomer (by active species generated by the decomposition) For the purpose of proceeding the polymerization of B) and sufficiently curing the patterned coating film, the entire surface can be irradiated (post-exposure). The exposure amount in the post-exposure is usually 1 to 1500 mJ / cm ² . Furthermore, heat treatment (post-bake) can be performed for the purpose of sufficiently curing the patterned coating film. The post-baking conditions can be appropriately selected depending on the type and amount of each component, but are usually about 150 to 250 ° C. for about 10 to 120 minutes.

  By using the obtained patterned coating film as a partition for electronic paper, a partition for electronic paper is formed.

[3] Partition for Electronic Paper The partition for electronic paper of the present invention is included in the above-mentioned “[2] Method for forming partition for electronic paper” or included in the photosensitive composition for partition formation of the present invention. Since the polymer (A) has the structural unit (a1) having a phenolic hydroxyl group and the structural unit (a2) having an alicyclic hydrocarbon group, the partition for electronic paper of the present invention is phenolic. It has the structure derived from a hydroxyl group and an alicyclic hydrocarbon group.

  The above “the partition for electronic paper has a structure derived from a phenolic hydroxyl group and an alicyclic hydrocarbon group” means that when the partition for electronic paper is analyzed by, for example, NMR, mass spectrometry and gas chromatography, phenolic A structure derived from a hydroxyl group and a structure derived from an alicyclic hydrocarbon group can be detected.

  When the partition for electronic paper has a structure derived from a phenolic hydroxyl group and an alicyclic hydrocarbon group, the partition can maintain a rectangle during heating.

  The size of the partition for electronic paper can be appropriately selected depending on the method applied. For example, in the case of the vertical electrophoretic display system, the partition wall has a width of 10 to 50 μm and a partition wall height of 10 to 100 μm in the cross section of the partition wall in a plane perpendicular to the substrate.

[4] Electronic paper The electronic paper according to the present invention includes a “[3] partition for electronic paper”, a pair of electrode substrates facing each other through the partition, a plurality of partition walls and the electrode substrate. It has a cell and the component containing the charged particle at least accommodated in the said cell.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. “Parts” and “%” are based on mass unless otherwise specified.

1. Synthesis of Polymer [Synthesis Example 1] Synthesis of Polymer (A1) In a reaction vessel, 5 parts of 2,2-azoisobutyronitrile as a polymerization catalyst, 150 parts of propylene glycol monomethyl ether acetate as a polymerization solvent, As monomers, 11 parts of methacrylic acid (a3-1), 39 parts of isobornyl acrylate (a2-1), 30 parts of α-methyl-p-hydroxystyrene (a1-1), tricyclo [5. 2.1.0 ^2,6 ] decan-8-yl methacrylate (a2-2) 15 parts, phenoxydiethylene glycol methacrylate (a3-2) 5 parts, chain transfer agent, tert-dodecyl mercaptan 0.2 parts To form a mixed solution. The resulting mixed solution was heated at 80 ° C. for 3 hours. After adding 2 parts of 2,2-azoisobutyronitrile to the mixed solution after heating, this was heated at 80 ° C. for 3 hours, and then heated at 100 ° C. for 1 hour. The mixed solution after heating was cooled to 23 ° C. to obtain a solution containing the polymer (A1).

[Synthesis Examples 2 to 6] Synthesis of Polymers (A2 to A4, AR1 and AR2) A polymerization catalyst and a polymerization solution of the same type and amount as those of Synthesis Example 1 except that the amounts of monomers shown in Table 1 below were used. And a polymer (A2-A4, AR1, and AR2) was obtained in the same manner as in Synthesis Example 1 using a chain transfer agent. In Table 1, the weight average molecular weight determined by gel permeation column chromatography is also shown.

2. Preparation of photosensitive composition for partition wall formation [Examples 2 to 5, Comparative Examples 1 and 2] Preparation of photosensitive composition for partition wall formation of Examples 1 to 5 and Comparative Examples 1 and 2 By blending and dissolving the respective components, the barrier rib forming photosensitive compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were obtained. The details of each component in Table 1 are as follows.

B1: Pentaerythritol tetraacrylate C1: 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name “Irgacure 651”, manufactured by Ciba Specialty Chemicals)
C2: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name “Lucirin LR8953X”, manufactured by BASF)
D1: Propylene glycol monomethyl ether acetate E1: Silane coupling agent, tris- (3-trimethoxysilylpropyl) isocyanurate (trade name “Y-11597”, manufactured by Momentive)
E2: Fluorosurfactant (trade name “FTX-218F”, manufactured by Neos)

3. Formation of partition walls [Example 6]
On the 6-inch wafer having a silicon oxide film on the surface, the barrier rib-forming photosensitive composition of Example 1 was applied and heat-treated with a hot plate at 120 ° C. for 5 minutes to form a coating film having a thickness of 58 μm. The formed coating film was exposed to ultraviolet rays irradiated from a high-pressure mercury lamp through a patterned mask using an aligner (manufactured by Karl Suss, model “MA-150”). The exposed coating film was developed with an aqueous solution containing 2.0% by mass of potassium hydroxide, and then washed with water to form a patterned coating film having a line width of 40 μm, a pitch of 80 μm, and a height of 50 μm. . The obtained patterned coating film is used as the partition wall of Example 6.

[Examples 7 to 10, Comparative Examples 3 and 4]
The partition walls of Examples 7 to 10 and Comparative Examples 3 and 4 were prepared in the same manner as in Example 6 except that the partition walls shown in Table 3 were formed using the photosensitive composition for partition wall formation shown in Table 3 below. (Line width 40 μm, pitch 80 μm, height 50 μm).

4). Evaluation 4-1. Heat resistance of the partition wall The size of the partition wall before the heat treatment was observed with an electron microscope for the cross-sectional shape of the partition wall obtained in “3. Formation of partition wall”. The partition wall width at the top of the partition wall (top width) and the size obtained by subtracting the bottom width from the top width (difference width) were measured.
The size of the partition walls after the heat treatment is as follows. The substrate having the partition walls obtained in “3. Formation of partition walls” is heated in an oven at 220 ° C. for 1 hour, and then the shape of the partition walls after the heat treatment is performed. Were observed with an electron microscope, and the width of the partition wall (bottom width) in contact with the substrate, the width of the partition wall at the top of the partition wall (top width), and the size obtained by subtracting the bottom width from the top width (difference width) were measured.
The heat resistance of the partition walls was evaluated by the amount of change in the difference width before and after the heat treatment. If the amount of change is smaller than 5 μm, it can be estimated that the partition wall is excellent in heat resistance. The results are shown in Table 3.

  Since the partition for electronic paper of the present invention can form a partition that can maintain a rectangular shape when heated, a method that requires a partition in the electronic paper; for example, a vertical electrophoresis method in an electrophoresis method and a horizontal electrophoresis method. The electrophoretic method, the magnetophoretic method, the electropowder fluid method, the charged toner type display method, the electromic method, and the like can be used. Moreover, the photosensitive composition for partition formation for forming the said partition for electronic paper, the formation method of the partition for electronic paper, and electronic paper can be usefully used by these various systems.

DESCRIPTION OF SYMBOLS 10; Board | substrate 20; Coating film 30; Latent image 40; Patterned mask 50; Patterned coating film 60; Cavity 100;

Claims (7)

A photosensitive composition for forming a partition, which is used to form a partition for electronic paper and contains the following components (A) to (D).
(A) Component: A polymer having a structural unit (a1) having a phenolic hydroxyl group and a structural unit (a2) having an alicyclic hydrocarbon group.
(B) component: a polyfunctional monomer.
Component (C): photosensitive polymerization initiator.
Component (D): an organic solvent.   The photosensitive composition for partition formation according to claim 1, wherein the content ratio of the structural unit (a1) is 1 to 40% by mass when the total structural unit in the polymer (A) is 100% by mass.   The partition wall formation according to any one of claims 1 and 2, wherein when the total structural unit in the polymer (A) is 100 mass%, the content ratio of the structural unit (a2) is 10 to 80 mass%. Photosensitive composition. A method for forming a partition for electronic paper, comprising the following steps (1) to (3).
Process (1): The process of forming the coating film obtained from the photosensitive composition for partition formation of any one of Claims 1 thru | or 3 on a board | substrate.
Step (2): A step of exposing the coating film obtained in step (1) so as to correspond to the partition walls.
Process (3): The process of developing the coating film after exposure obtained at the process (2).   The partition for electronic paper obtained by the formation method of the partition for electronic paper of Claim 4.   A partition for electronic paper having a structure derived from a phenolic hydroxyl group and an alicyclic hydrocarbon group.   The partition for electronic paper of any one of Claim 5 or 6, a pair of electrode substrate which opposes via the said partition, the some cell comprised by the said partition and the said electrode substrate, The said cell And an electronic paper having at least a charged particle-containing component.

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