WO2021200355A1

WO2021200355A1 - Radiation sensitive sheet and patterned sheet

Info

Publication number: WO2021200355A1
Application number: PCT/JP2021/011796
Authority: WO
Inventors: 圭一梶田; 杉田　光
Original assignee: 王子ホールディングス株式会社; Jsr株式会社
Priority date: 2020-03-30
Filing date: 2021-03-22
Publication date: 2021-10-07
Also published as: TW202204488A; JPWO2021200355A1

Abstract

The present invention addresses the problem of providing: a radiation sensitive sheet which is capable of being provided with a fine pattern, while exhibiting excellent transparency; and a patterned sheet which is obtained by removing at least a part of a light exposed part or a light unexposed part of this radiation sensitive sheet.　A radiation sensitive sheet according to the present invention contains a radiation sensitive composition, microfibrous cellulose that has a fiber width of 1,000 nm or less, and a hydrophilic polymer; and the content of the hydrophilic polymer relative to 100 parts by mass of the microfibrous cellulose is 10 parts by mass or more.

Description

Radiation-sensitive sheets and patterned sheets

The present invention relates to a radiation-sensitive sheet and a patterned sheet in which at least a part of an exposed portion or an unexposed portion of the radiation-sensitive sheet is removed.

In the development of electronic devices, there is a demand for a base material capable of fine patterning in accordance with the demand for miniaturization and high density of circuit configurations.
In addition, due to growing awareness of the use of renewable resources, it is being studied to apply compounds derived from plant raw materials such as cellulose nanofibers to various uses.
Patent Document 1 describes a fiber-reinforced composite material that is not affected by temperature conditions, wavelengths, etc., always maintains high transparency, and is endowed with various functions by combining fibers and a matrix material. For the purpose of providing, a fiber-reinforced composite material containing fibers having an average fiber diameter of 4 to 200 nm and a matrix material and having a light transmittance of 60% or more at a wavelength of 400 to 700 nm in terms of 50 μm thickness is disclosed. There is.

Further, Patent Document 2 discloses a photosensitive composite sheet containing a photosensitive resin and a photosensitive agent in a porous cellulose sheet, which satisfies at least the following requirements.
Requirement 1: The air permeability resistance of the porous cellulose sheet is 1 s / 100 ml or more and 400,000 s / 100 ml or less.
Requirement 2: The photosensitive resin contains at least one of a polymerizable compound, an alkali-soluble resin, and a resin in which the photofunctional group of the resin is protected by a protecting group.
Requirement 3: When the thickness of the photosensitive composite sheet is 50 μm, the light transmittance at a wavelength of 280 nm to 433 nm is 10% or more.

Japanese Unexamined Patent Publication No. 2005-60680 JP-A-2018-132655

The sheet described in Patent Document 1 has a problem that it is difficult to form a fine pattern. Further, the sheet described in Patent Document 2 has a problem of low transparency.
According to the present invention, a radiation-sensitive sheet capable of forming a fine pattern and having excellent transparency, and a patterned portion in which at least a part of an exposed portion or an unexposed portion of the radiation-sensitive sheet is removed. The purpose is to provide a sheet.

The present inventor has found that the above-mentioned problems can be solved by a radiation-sensitive sheet containing a specific amount of a hydrophilic polymer in addition to the radiation-sensitive composition and fine fibrous cellulose, and completed the present invention. I came to do it.
That is, the present invention relates to the following <1> to <13>.
<1> A radiation-sensitive composition, fine fibrous cellulose having a fiber width of 1,000 nm or less, and a hydrophilic polymer are contained, and the content of the hydrophilic polymer with respect to 100 parts by mass of the fine fibrous cellulose is 10 mass by mass. Radiation-sensitive sheet that is more than a part.
<2> The method according to <1>, wherein the radiation-sensitive composition comprises a radiation-sensitive compound and a resin for a radiation-sensitive composition whose solubility in a solvent is increased or decreased by the irradiated radiation-sensitive compound. Radiation sensitive sheet.
<3> The radiation-sensitive sheet according to <2>, wherein the radiation-sensitive compound contains at least one of a photoacid generator and a photopolymerization initiator.
<4> The radiation-sensitive sheet according to any one of <1> to <3>, wherein the content of the radiation-sensitive composition in the solid content of the radiation-sensitive sheet is 10% by mass or more.
<5> The radiation-sensitive sheet according to any one of <1> to <4>, wherein the total light transmittance of the radiation-sensitive sheet is 70% or more.
<6> The radiation-sensitive sheet according to any one of <1> to <5>, wherein the haze of the radiation-sensitive sheet is 10% or less.
<7> The radiation-sensitive sheet according to any one of <1> to <6>, wherein the fine fibrous cellulose has an anionic group.
<8> The radiation-sensitive sheet according to any one of <1> to <7>, wherein the fine fibrous cellulose has a phosphoric acid group or a group derived from a phosphoric acid group.
<9> The radiation-sensitive sheet according to any one of <1> to <8>, wherein the radiation-sensitive composition is dissolved in at least one of water, alcohol, and a mixed solvent thereof.
<10> The radiation-sensitive sheet according to any one of <1> to <9>, wherein the hydrophilic polymer is selected from polyethylene glycol, polyethylene oxide, polyvinyl alcohol, and modified polyvinyl alcohol.
<11> The radiation-sensitive sheet according to any one of <1> to <10>, wherein the radiation-sensitive sheet is a negative type radiation-sensitive sheet.
<12> A patterned sheet from which at least a part of an exposed portion or an unexposed portion of the radiation-sensitive sheet according to any one of <1> to <11> has been removed.
<13> The radiation-sensitive composition used for the radiation-sensitive sheet according to any one of <1> to <11>.

According to the present invention, a radiation-sensitive sheet capable of forming a fine pattern and having excellent transparency, and a pattern in which at least a part of an exposed portion or an unexposed portion of the radiation-sensitive sheet is removed. It is possible to provide a modified sheet.

FIG. 1 is a graph showing the relationship between the amount of NaOH added dropwise and the pH of a fibrous cellulose-containing slurry having a phosphorus oxo acid group. FIG. 2 is a graph showing the relationship between the amount of NaOH added dropwise to the fibrous cellulose-containing slurry having a carboxy group and the pH.

[Radiation-sensitive sheet]
The radiation-sensitive sheet of the present embodiment contains a radiation-sensitive composition, fine fibrous cellulose having a fiber width of 1,000 nm or less (hereinafter, also simply referred to as fine fibrous cellulose), and a hydrophilic polymer. The content of the hydrophilic polymer with respect to 100 parts by mass of the fine fibrous cellulose is 10 parts by mass or more.
According to this embodiment, a radiation-sensitive sheet capable of forming a fine pattern and having excellent transparency can be obtained.
The detailed reason why the above-mentioned effects are obtained is unknown, but some of them are considered as follows. In the present embodiment, the radiation-sensitive sheet itself has excellent shape stability and functions as a substrate, instead of providing the radiation-sensitive layer on the substrate. When the radiation-sensitive layer is provided on the substrate, problems such as curl generation due to the difference in thermal expansion coefficient from the substrate and light reflection at the interface may occur. No problem occurs.
Further, since the sheet containing the fine fibrous cellulose has extremely high transparency and the fiber width is 1,000 nm or less, it is considered that a fine pattern can be formed.
Further, when the radiation-sensitive layer (resist) is provided on the substrate, after patterning, a region where the radiation-sensitive layer (resist) exists and a region where the radiation-sensitive layer (resist) does not exist are generated, so that the film thickness becomes uneven. .. On the other hand, in the present embodiment, after exposure, at least a part of the exposed portion or the unexposed portion of the radiation-sensitive composition is removed, but mainly only the radiation-sensitive composition is removed, and fine fibrous cellulose and hydrophilic. Since the sex polymer remains as it is in the form of a sheet, patterning can be performed without causing unevenness in the overall film thickness.
Hereinafter, the present embodiment will be described in more detail.

<Fine fibrous cellulose>
The radiation-sensitive sheet of the present embodiment contains fine fibrous cellulose.
The fine fibrous cellulose is a fibrous cellulose having a fiber width of 1,000 nm or less. The fiber width of the fibrous cellulose can be measured by, for example, observation with an electron microscope.
The fiber width of the fine fibrous cellulose is 1,000 nm or less. The fiber width of the fine fibrous cellulose is, for example, preferably 2 nm or more and 1,000 nm or less, more preferably 2 nm or more and 100 nm or less, further preferably 2 nm or more and 50 nm or less, and 2 nm or more and 30 nm or less. It is even more preferable, and it is particularly preferable that it is 2 nm or more and 10 nm or less. By setting the fiber width of the fine fibrous cellulose to 2 nm or more, it is possible to suppress the dissolution of the fine fibrous cellulose in water as a cellulose molecule, and to make it easier to exhibit the effects of improving the strength, rigidity and dimensional stability of the fine fibrous cellulose. Can be done.

The average fiber width of fine fibrous cellulose is, for example, 1,000 nm or less. The average fiber width of the fine fibrous cellulose is preferably 2 nm or more and 1,000 nm or less, more preferably 2 nm or more and 100 nm or less, further preferably 2 nm or more and 50 nm or less, and 2 nm or more and 30 nm or less. It is even more preferable, and it is particularly preferable that it is 2 nm or more and 10 nm or less. By setting the average fiber width of the fine fibrous cellulose to 2 nm or more, it is possible to suppress the dissolution of the fine fibrous cellulose in water as a cellulose molecule, and to more easily exhibit the effects of the fine fibrous cellulose to improve strength, rigidity and dimensional stability. be able to. The fine fibrous cellulose is, for example, monofibrous cellulose.

The average fiber width of the fine fibrous cellulose is measured as follows, for example, using an electron microscope. First, an aqueous suspension of fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less is prepared, and this suspension is cast on a hydrophilized carbon film-coated grid to prepare a sample for TEM observation. And. If it contains wide fibers, an SEM image of the surface cast on the glass may be observed. Next, observation is performed using an electron microscope image at a magnification of 1,000 times, 5,000 times, 10,000 times, or 50,000 times depending on the width of the fiber to be observed. However, the sample, observation conditions and magnification should be adjusted so as to satisfy the following conditions.
(1) A straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y that intersects the straight line perpendicularly is drawn in the same image, and 20 or more fibers intersect the straight line Y.

For an observation image that satisfies the above conditions, visually read the width of the fiber that intersects the straight line X and the straight line Y. In this way, at least three sets of observation images of surface portions that do not overlap each other are obtained. Next, for each image, the width of the fiber intersecting the straight line X and the straight line Y is read. As a result, at least 20 fibers × 2 × 3 = 120 fibers are read. Then, the average value of the read fiber widths is taken as the average fiber width of the fibrous cellulose.

The fiber length of the fine fibrous cellulose is not particularly limited, but is preferably 0.1 μm or more and 1,000 μm or less, more preferably 0.1 μm or more and 800 μm or less, and 0.1 μm or more and 600 μm or less. Is even more preferable. By setting the fiber length within the above range, destruction of the crystal region of the fine fibrous cellulose can be suppressed. It is also possible to set the slurry viscosity of the fine fibrous cellulose in an appropriate range. The fiber length of the fine fibrous cellulose can be obtained by, for example, image analysis by TEM, SEM, or AFM.

The fine fibrous cellulose preferably has an I-type crystal structure. Here, the fact that the fine fibrous cellulose has an I-type crystal structure can be identified in the diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418 Å) monochromatic with graphite. Specifically, it can be identified by having typical peaks at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less.
The ratio of the type I crystal structure to the fine fibrous cellulose is, for example, preferably 30% or more, more preferably 40% or more, and further preferably 50% or more. As a result, even better performance can be expected in terms of heat resistance and low coefficient of linear thermal expansion. The crystallinity is determined by a conventional method from the X-ray diffraction profile measured and the pattern (Seagal et al., Textile Research Journal, Vol. 29, p. 786, 1959).

The axial ratio (fiber length / fiber width) of the fine fibrous cellulose is not particularly limited, but is preferably 20 or more and 10,000 or less, and more preferably 50 or more and 1,000 or less. By setting the axial ratio to the above lower limit value or more, it is easy to form a sheet containing fine fibrous cellulose. In addition, sufficient viscosity can be easily obtained when the solvent dispersion is produced. By setting the axial ratio to the above upper limit value or less, for example, when treating fine fibrous cellulose as an aqueous dispersion, it is preferable in that handling such as dilution becomes easy.

The fine fibrous cellulose in this embodiment has, for example, at least one of an ionic group and a nonionic group. From the viewpoint of improving the dispersibility of the fibers in the dispersion medium and increasing the defibration efficiency in the defibration treatment, it is more preferable that the fine fibrous cellulose has an ionic group. The ionic substituent can include, for example, either one or both of an anionic group and a cationic group. In this embodiment, it is particularly preferable to have an anionic group as the ionic substituent. Further, the ionic substituent is preferably a group linked to the fibrous cellulose via an ester bond. In this case, the ester bond is formed by dehydration condensation of the fibrous cellulose and the compound serving as an ionic substituent.
The fine fibrous cellulose may not be subjected to a treatment for introducing an ionic group.

Examples of the anionic group as an ionic group include a phosphoric acid group or a substituent derived from a phosphoric acid group (sometimes simply referred to as a phosphoric acid group), a carboxy group or a substituent derived from a carboxy group (simply referred to as a carboxy group). (Sometimes), a sulfur oxo acid group or a substituent derived from a sulfur oxo acid group (sometimes simply referred to as a sulfur oxo acid group), a zantate group, a phosphone group, a phosphine group, a sulfone group, a carboxyalkyl group, etc. Can be done. Among them, the anionic group is selected from the group consisting of a phosphorus oxo acid group, a substituent derived from a phosphorus oxo acid group, a carboxy group, a sulfur oxo acid group, a substituent derived from a sulfur oxo acid group, a carboxymethyl group and a sulfone group. At least one selected from the group consisting of a phosphorus oxo acid group, a substituent derived from a phosphorus oxo acid group, a carboxy group, a sulfur oxo acid group, and a substituent derived from a sulfur oxo acid group. It is more preferably a species, especially a phosphoroxoic acid group. By introducing a phosphorus oxo acid group as an anionic group, for example, the dispersibility of fibrous cellulose can be further enhanced even under alkaline or acidic conditions, and as a result, a high-strength and highly transparent sheet can be obtained. It will be easier.
Examples of the cationic group as the ionic group include an ammonium group, a phosphonium group, a sulfonium group and the like. Of these, the cationic group is preferably an ammonium group.

The phosphate group or the substituent derived from the phosphorus oxo acid group is, for example, a substituent represented by the following formula (1). A plurality of types of substituents represented by the following formula (1) may be introduced into each fibrous cellulose. In this case, the substituents represented by the following formula (1) to be introduced may be the same or different.
The phosphorus oxo acid group is, for example, a divalent functional group obtained by removing a hydroxy group from phosphoric acid. Specifically, it is a group represented by _{-PO 3} H _2. Substituents derived from a phosphorus oxo acid group include substituents such as a salt of a phosphorus oxo acid group and a phosphorus oxo acid ester group. The substituent derived from the phosphoric acid group may be contained in the fibrous cellulose as a group in which the phosphoric acid group is condensed (for example, a pyrophosphate group). Further, the phosphoric acid group may be, for example, a phosphite group (phosphonic acid group), and the substituent derived from the phosphoric acid group is a salt of the phosphite group, a phosphite ester group, or the like. May be good.

In the formula (1), a, b and n are natural numbers, and m is an arbitrary number (where a = b × m). At least one of the n α and α'is O ⁻ and the rest are R or OR. It is also possible that all of each α and α'are O ^−. The n αs may all be the same or different. β ^{b +} is a monovalent or higher cation composed of an organic substance or an inorganic substance.

R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, and an unsaturated-branched chain hydrocarbon, respectively. A hydrogen group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or an inducing group thereof. Further, in the formula (1), n is preferably 1. In addition, α in the formula (1) may be a group derived from a cellulose molecular chain.

Examples of the saturated-linear hydrocarbon group include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, an n-butyl group and the like. Examples of the saturated-branched chain hydrocarbon group include an i-propyl group and a t-butyl group, but are not particularly limited. Examples of the saturated-cyclic hydrocarbon group include, but are not limited to, a cyclopentyl group, a cyclohexyl group and the like. Examples of the unsaturated-linear hydrocarbon group include, but are not limited to, a vinyl group, an allyl group and the like. Examples of the unsaturated-branched chain hydrocarbon group include an i-propenyl group and a 3-butenyl group, but are not particularly limited. Examples of the unsaturated-cyclic hydrocarbon group include, but are not limited to, a cyclopentenyl group, a cyclohexenyl group and the like. Examples of the aromatic group include, but are not limited to, a phenyl group, a naphthyl group and the like.

As the derivative groups in R, to the main chain or side chain of the various hydrocarbon group, a carboxy group, a carboxylate group (-COO ^-), hydroxy group, selected from the functional groups such as amino groups and ammonium groups Examples thereof include functional groups in which at least one type is added or substituted, but the functional group is not particularly limited. The number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, and more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R to the above range, the molecular weight of the phosphorus oxo acid group can be set to an appropriate range, permeation into the fiber raw material is facilitated, and the yield of fine fibrous cellulose can be increased. It can also be increased. When a plurality of Rs are present in the formula (1) or when a plurality of types of substituents represented by the above formula (1) are introduced into the fibrous cellulose, the plurality of Rs present are the same. It may or may not be different.

β ^{b +} is a monovalent or higher cation composed of an organic substance or an inorganic substance. Examples of monovalent or higher cations composed of organic substances include organic onium ions. Examples of the organic onium ion include an organic ammonium ion and an organic phosphonium ion. Examples of the organic ammonium ion include an aliphatic ammonium ion and an aromatic ammonium ion, and examples of the organic phosphonium ion include an aliphatic phosphonium ion and an aromatic phosphonium ion. Examples of monovalent or higher cations composed of inorganic substances include alkali metal ions such as sodium, potassium, and lithium, divalent metal ions such as calcium and magnesium, hydrogen ions, and ammonium ions. These may be applied alone or in combination of two or more. When a ^{plurality of β b +} are present in the formula (1) or when a plurality of types of substituents represented by the above formula (1) are introduced into the fibrous cellulose, the plurality of β ^{b + present} are each. It may be the same or different. The monovalent or higher cation composed of an organic substance or an inorganic substance is preferably sodium or potassium ion which is hard to yellow when the fiber raw material containing ^{β b + is heated and is easily industrially used, but is not particularly limited.} ..

More specifically, the phosphoric acid group or the substituent derived from the phosphoric acid group includes a phosphoric acid group (-PO ₃ H ₂ ), a salt of a phosphoric acid group, and a phosphite group (phosphonic acid group) (-PO). ₂ H _2), and salts of phosphorous acid (phosphonic acid group). Further, the phosphoric acid group or the substituent derived from the phosphoric acid group includes a group in which a phosphoric acid group is condensed (for example, a pyrophosphate group), a group in which a phosphonic acid is condensed (for example, a polyphosphonic acid group), and a phosphoric acid ester group (for example, a phosphoric acid ester group). For example, it may be a monomethyl phosphate group, a polyoxyethylene alkyl phosphate group), an alkylphosphonic acid group (for example, a methylphosphonic acid group), or the like.

The sulfur oxoacid group (sulfur oxoacid group or a substituent derived from the sulfur oxoacid group) is, for example, a substituent represented by the following formula (2). A plurality of types of substituents represented by the following formula (2) may be introduced into each fibrous cellulose. In this case, the substituents represented by the following formula (2) to be introduced may be the same or different.

In the above structural formula, b and n are natural numbers, p is 0 or 1, and m is an arbitrary number (where 1 = b × m). When n is 2 or more, a plurality of ps may be the same number or different numbers. In the above structural formula, β ^{b +} is a monovalent or higher cation composed of an organic substance or an inorganic substance. Examples of monovalent or higher cations composed of organic substances include organic onium ions. Examples of the organic onium ion include an organic ammonium ion and an organic phosphonium ion. Examples of the organic ammonium ion include an aliphatic ammonium ion and an aromatic ammonium ion, and examples of the organic phosphonium ion include an aliphatic phosphonium ion and an aromatic phosphonium ion. Examples of monovalent or higher cations composed of inorganic substances include alkali metal ions such as sodium, potassium, and lithium, divalent metal ions such as calcium and magnesium, hydrogen ions, and ammonium ions. When a plurality of types of substituents represented by the above formula (2) are introduced into the fibrous cellulose, the plurality of β ^{b +} existing may be the same or different. The monovalent or higher cation composed of an organic substance or an inorganic substance is preferably sodium or potassium ion which is hard to yellow when the fiber raw material containing ^{β b + is heated and is easily industrially used, but is not particularly limited.} ..

The amount of the ionic group introduced into the cellulose fiber is, for example, 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.40 mmol / g or more per 1 g (mass) of the cellulose fiber. It is more preferably 0.50 mmol / g or more, further preferably 0.60 mmol / g or more, and particularly preferably 1.00 mmol / g or more. The amount of the ionic group introduced into the cellulose fiber is, for example, 5.20 mmol / g or less, more preferably 3.65 mmol / g or less, and 3.50 mmol / g / g per 1 g (mass) of the cellulose fiber. It is more preferably g or less, and even more preferably 3.00 mmol / g or less. By setting the amount of the ionic group introduced within the above range, it is possible to facilitate the miniaturization of the fiber raw material and enhance the stability of the fine fibrous cellulose. Further, by setting the amount of the ionic group introduced within the above range, good characteristics can be exhibited in various applications such as a thickener for fine fibrous cellulose.
Here, the denominator in the unit mmol / g indicates the mass of the fine fibrous cellulose when the counter ion of the ionic group is a hydrogen ion (H ^+).

The amount of the ionic group introduced into the fibrous cellulose can be measured by, for example, a neutralization titration method. In the measurement by the neutralization titration method, the introduction amount is measured by determining the change in pH while adding an alkali such as an aqueous sodium hydroxide solution to the obtained slurry containing fibrous cellulose.
FIG. 1 is a graph showing the relationship between the amount of NaOH added dropwise to fibrous cellulose having a phosphorus oxo acid group and pH.

FIG. 1 is a graph showing the relationship between the amount of NaOH added dropwise and the pH of a fibrous cellulose-containing slurry having a phosphorus oxo acid group. The amount of the phosphorus oxo acid group introduced into the fibrous cellulose is measured, for example, as follows.
First, the slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, the defibration treatment similar to the defibration treatment step described later may be performed on the measurement target before the treatment with the strongly acidic ion exchange resin.
Next, the change in pH is observed while adding an aqueous sodium hydroxide solution, and a titration curve as shown in the upper part of FIG. 1 is obtained. The titration curve shown in the upper part of FIG. 1 plots the measured pH with respect to the amount of alkali added, and the titration curve shown in the lower part of FIG. 1 plots the pH with respect to the amount of alkali added. The increment (differential value) (1 / mmol) is plotted. In this neutralization titration, two points are confirmed in which the increment (differential value of pH with respect to the amount of alkali dropped) becomes maximum in the curve plotting the measured pH with respect to the amount of alkali added. Of these, the maximum point of the increment obtained first when alkali is added is called the first end point, and the maximum point of the increment obtained next is called the second end point. The amount of alkali required from the start of titration to the first end point is equal to the amount of first dissociated acid of the fibrous cellulose contained in the slurry used for titration, and the amount of alkali required from the first end point to the second end point. The amount is equal to the amount of the second dissociating acid of the fibrous cellulose contained in the slurry used for the titration, and the amount of alkali required from the start to the second end point of the titration is the fibrous cellulose contained in the slurry used for the titration. Is equal to the total amount of dissociated acid. Then, the value obtained by dividing the amount of alkali required from the start of titration to the first end point by the solid content (g) in the slurry to be titrated is the amount of phosphorus oxo acid group introduced (mmol / g). The amount of phosphorus oxo acid group introduced (or the amount of phosphorus oxo acid group) simply means the amount of the first dissociated acid.
In FIG. 1, the region from the start of titration to the first end point is referred to as a first region, and the region from the first end point to the second end point is referred to as a second region. For example, when the phosphoric acid group is a phosphoric acid group and the phosphoric acid group causes condensation, the amount of weakly acidic groups in the phosphoric acid group (also referred to as the second dissociated acid amount in the present specification) is apparently It decreases, and the amount of alkali required for the second region is smaller than the amount of alkali required for the first region. On the other hand, the amount of strongly acidic groups in the phosphorus oxo acid group (also referred to as the first dissociated acid amount in the present specification) is the same as the amount of phosphorus atoms regardless of the presence or absence of condensation. When the phosphorous acid group is a phosphorous acid group, the weakly acidic group does not exist in the phosphorous acid group, so that the amount of alkali required for the second region is reduced or the amount of alkali required for the second region is reduced. May be zero. In this case, there is only one point on the titration curve where the pH increment is maximized.
Since the denominator of the above-mentioned phosphorus oxo acid group introduction amount (mmol / g) indicates the mass of the acid-type fibrous cellulose, the phosphorus oxo acid group amount of the acid-type fibrous cellulose (hereinafter, the phosphorus oxo acid group amount). (Called (acid type))). On the other hand, when the counterion of the phosphorus oxo acid group is replaced with an arbitrary cation C so as to have a charge equivalent, the denominator is converted into the mass of fibrous cellulose when the cation C is a counterion. This makes it possible to determine the amount of phosphorus oxo acid groups (hereinafter, the amount of phosphorus oxo acid groups (C type)) possessed by the fibrous cellulose in which the cation C is a counter ion.
That is, it is calculated by the following formula.
Amount of phosphorus oxo acid group (C type) = Amount of phosphorus oxo acid group (acid type) / {1+ (W-1) x A / 1000}
A [mmol / g]: Total anion amount derived from the phosphoric acid group of the fibrous cellulose (the sum of the strong acid group amount and the weakly acidic group amount of the phosphoric acid group).
W: Formula unit of cation C per valence (for example, Na is 23, Al is 9)

FIG. 2 is a graph showing the relationship between the amount of NaOH added dropwise to fibrous cellulose having a carboxy group and pH.
The amount of carboxy group introduced into the fibrous cellulose is measured, for example, as follows.
First, the slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, the defibration treatment similar to the defibration treatment step described later may be performed on the measurement target before the treatment with the strongly acidic ion exchange resin. Next, the change in pH is observed while adding an aqueous sodium hydroxide solution, and a titration curve as shown in FIG. 2 is obtained. If necessary, the same defibration treatment as the defibration treatment step described later may be performed on the measurement target.
As shown in FIG. 2, in this neutralization titration, there is one point where the increment (differential value of pH with respect to the amount of alkaline drop) becomes maximum in the curve plotting the measured pH with respect to the amount of alkali added. Observed. The maximum point of this increment is called the first end point. Here, the region from the start of titration to the first end point in FIG. 2 is referred to as a first region. The amount of alkali required in the first region is equal to the amount of carboxy groups in the slurry used for titration. Then, the amount of alkali (mmol) required in the first region of the titration curve is divided by the solid content (g) in the fine fibrous cellulose-containing slurry to be titrated, so that the amount of carboxy group introduced (mmol / g). ) Was calculated.
The above-mentioned amount of carboxy group introduced (mmol / g) is the amount of substituents per 1 g of mass of fibrous cellulose when the ^{counter ion of the carboxy group is hydrogen ion (H +) (hereinafter, the amount of carboxy group (acid).} Type)) is shown.

Since the denominator of the above-mentioned carboxy group introduction amount (mmol / g) is the mass of the acid type fibrous cellulose, the carboxy group amount of the acid type fibrous cellulose (hereinafter, the carboxy group amount (acid type)). ) Is shown. On the other hand, when the counterion of the carboxy group is replaced with an arbitrary cation C so as to have a charge equivalent, the denominator is converted to the mass of fibrous cellulose when the cation C is a counterion. Then, the amount of carboxy groups (hereinafter, the amount of carboxy groups (C type)) (mmol / g) possessed by the fibrous cellulose in which the cation C is a counter ion can be determined.
That is, it is calculated by the following formula.
Amount of carboxy group (C type) = Amount of carboxy group (acid type) / {1+ (W-1) x (amount of carboxy group (acid type)) / 1000}
W: Formula unit of cation C per valence (for example, Na is 23, Al is 9)

In the measurement of the amount of substituents by the titration method, if the amount of one drop of the sodium hydroxide aqueous solution is too large or the titration interval is too short, an accurate value such as a lower amount of substituents can be obtained. Sometimes not. As an appropriate dropping amount and titration interval, for example, it is desirable to titrate 10 to 50 μL of a 0.1 N sodium hydroxide aqueous solution every 5 to 30 seconds. Further, in order to eliminate the influence of carbon dioxide dissolved in the fibrous cellulose-containing slurry, for example, it is desirable to measure while blowing an inert gas such as nitrogen gas into the slurry from 15 minutes before the start of titration to the end of titration.

The amount of sulfur oxoacid group introduced into the fibrous cellulose is determined by wet ashing the obtained fibrous cellulose with perchloric acid and concentrated nitric acid, diluting it at an appropriate magnification, and analyzing the amount of sulfur by ICP luminescence analysis. To measure.
The value obtained by dividing this amount of sulfur by the absolute dry mass of the fibrous cellulose tested is defined as a sulfur oxoacid group (unit: mmol / g).

The measurement of the amount of ionic groups by the above method is applied to fine fibrous cellulose having a fiber width of 1,000 nm or less, and when measuring the amount of ionic groups of pulp fibers having a fiber width of more than 1,000 nm, , It is preferable to measure after making the pulp fiber finer.

[Manufacturing method of fine fibrous cellulose]
(Fiber raw material containing cellulose)
Fine fibrous cellulose is produced from a fiber raw material containing cellulose.
The fiber raw material containing cellulose is not particularly limited, but pulp is preferably used because it is easily available and inexpensive. Examples of pulp include wood pulp, non-wood pulp, and deinked pulp. The wood pulp is not particularly limited, but is, for example, broadleaf kraft pulp (LBKP), coniferous kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), and unbleached kraft pulp (UKP). ) And chemical pulp such as oxygen bleached kraft pulp (OKP), semi-chemical pulp such as semi-chemical pulp (SCP) and chemiground wood pulp (CGP), crushed wood pulp (GP) and thermomechanical pulp (TMP, BCTMP), etc. Examples include mechanical pulp. The non-wood pulp is not particularly limited, and examples thereof include cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as hemp, straw, bamboo, and bagasse. The deinking pulp is not particularly limited, and examples thereof include deinking pulp made from recycled paper. As the pulp of the present embodiment, one of the above types may be used alone, or two or more types may be mixed and used.
Among the above pulps, for example, wood pulp and deinked pulp are preferable from the viewpoint of availability. Further, among wood pulps, from the viewpoint of high cellulose ratio and high yield of fine fibrous cellulose during defibration treatment, long fiber fine fibrous cellulose having a small decomposition of cellulose in pulp and a large axial ratio can be obtained. From the viewpoint, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are further preferable. When long fiber fine fibrous cellulose having a large axial ratio is used, the viscosity tends to be high.
As the fiber raw material containing cellulose, for example, cellulose contained in ascidians and bacterial cellulose produced by acetic acid bacteria can also be used.
Further, instead of the fiber raw material containing cellulose, a fiber formed by a linear nitrogen-containing polysaccharide polymer such as chitin or chitosan can also be used.

In order to obtain the above-mentioned fine fibrous cellulose into which an ionic group has been introduced, an ionic group introduction step, a washing step, and an alkali treatment step (neutralization step) in which the ionic group is introduced into the above-mentioned fiber raw material containing cellulose ), It is preferable to have the defibration treatment step in this order, and the acid treatment step may be provided instead of the washing step or in addition to the washing step. Examples of the ionic group introduction step include a phosphorus oxo acid group introduction step and a carboxy group introduction step. Each will be described below.

(Ionic group introduction process)
-Linoxo acid group introduction process-
In the phosphorus oxo acid group introduction step, at least one compound (hereinafter, also referred to as “compound A”) selected from compounds capable of introducing a phosphorus oxo acid group by reacting with a hydroxyl group of a fiber raw material containing cellulose is introduced into cellulose. It is a step of acting on a fiber raw material containing. By this step, a phosphorus oxo acid group-introduced fiber can be obtained.
In the phosphoric acid group introduction step according to the present embodiment, the reaction between the fiber raw material containing cellulose and Compound A is carried out in the presence of at least one selected from urea and its derivatives (hereinafter, also referred to as “Compound B”). You may. On the other hand, the reaction of the fiber raw material containing cellulose with the compound A may be carried out in the absence of the compound B.
As an example of the method of allowing the compound A to act on the fiber raw material in the coexistence with the compound B, a method of mixing the compound A and the compound B with the fiber raw material in a dry state, a wet state or a slurry state can be mentioned. Of these, since the reaction uniformity is high, it is preferable to use a fiber raw material in a dry state or a wet state, and it is particularly preferable to use a fiber raw material in a dry state. The form of the fiber raw material is not particularly limited, but is preferably cotton-like or thin sheet-like, for example. Examples of the compound A and the compound B include a method of adding the compound A and the compound B to the fiber raw material in the form of a powder or a solution dissolved in a solvent, or in a state of being heated to a melting point or higher and melted. Of these, since the reaction is highly homogeneous, it is preferable to add the mixture in the form of a solution dissolved in a solvent, particularly in the form of an aqueous solution. Further, the compound A and the compound B may be added to the fiber raw material at the same time, may be added separately, or may be added as a mixture. The method of adding the compound A and the compound B is not particularly limited, but when the compound A and the compound B are in the form of a solution, the fiber raw material may be immersed in the solution to absorb the liquid and then taken out, or the fiber raw material may be taken out. The solution may be dropped into the water. Further, the required amounts of compound A and compound B may be added to the fiber raw material, or after the excess amounts of compound A and compound B are added to the fiber raw material, the surplus compound A and compound B are added by pressing or filtering. It may be removed.

The compound A used in this embodiment may be a compound having a phosphorus atom and capable of forming an ester bond with cellulose, and may be phosphoric acid or a salt thereof, phosphoric acid or a salt thereof, dehydration-condensed phosphoric acid or a salt thereof. Examples thereof include salts and anhydrous phosphoric acid (diphosphoric pentoxide), but the present invention is not particularly limited. As the phosphoric acid, those having various puritys can be used, and for example, 100% phosphoric acid (normal phosphoric acid) or 85% phosphoric acid can be used. Examples of phosphorous acid include 99% phosphorous acid (phosphonic acid). The dehydration-condensed phosphoric acid is obtained by condensing two or more molecules of phosphoric acid by a dehydration reaction, and examples thereof include pyrophosphoric acid and polyphosphoric acid. Examples of phosphates, phosphites, and dehydration-condensed phosphates include lithium salts, sodium salts, potassium salts, and ammonium salts of phosphoric acid, phosphite or dehydration-condensed phosphoric acid, and these are among various types. It can be a sum.
Of these, from the viewpoints of high efficiency of introduction of phosphoric acid group, easy improvement of defibration efficiency in the defibration step described later, low cost, and easy industrial application, phosphoric acid and phosphoric acid A sodium salt, a potassium salt of phosphoric acid, or an ammonium salt of phosphoric acid is preferable, and phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, or ammonium dihydrogen phosphate is more preferable.
The amount of compound A added to the fiber raw material is not particularly limited, but for example, when the amount of compound A added is converted to the phosphorus atomic weight, the amount of phosphorus atom added to the fiber raw material (absolute dry mass) is 0.5% by mass or more. It is preferably 100% by mass or less, more preferably 1% by mass or more and 50% by mass or less, and further preferably 2% by mass or more and 30% by mass or less. By setting the amount of phosphorus atom added to the fiber raw material within the above range, the yield of fine fibrous cellulose can be further improved. On the other hand, by setting the addition amount of the phosphorus atom to the fiber raw material to be equal to or less than the above upper limit value, the effect of improving the yield and the cost can be balanced.

Compound B used in this embodiment is at least one selected from urea and its derivatives as described above. Examples of compound B include urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like.
From the viewpoint of improving the uniformity of the reaction, compound B is preferably used as an aqueous solution. Further, from the viewpoint of further improving the uniformity of the reaction, it is preferable to use an aqueous solution in which both compound A and compound B are dissolved.
The amount of compound B added to the fiber raw material (absolute dry mass) is not particularly limited, but is preferably 1% by mass or more and 500% by mass or less, and more preferably 10% by mass or more and 400% by mass or less. It is more preferably 100% by mass or more and 350% by mass or less.

In the reaction between the fiber raw material containing cellulose and compound A, for example, amides or amines may be contained in the reaction system in addition to compound B. Examples of amides include formamide, dimethylformamide, acetamide, dimethylacetamide and the like. Examples of amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine and the like. Among these, triethylamine in particular is known to act as a good reaction catalyst.

In the phosphorus oxo acid group introduction step, it is preferable to add or mix compound A or the like to the fiber raw material and then heat-treat the fiber raw material. As the heat treatment temperature, it is preferable to select a temperature at which a phosphorus oxo acid group can be efficiently introduced while suppressing the thermal decomposition and hydrolysis reaction of the fiber. The heat treatment temperature is, for example, preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower. In addition, equipment having various heat media can be used for the heat treatment, for example, a stirring drying device, a rotary drying device, a disk drying device, a roll type heating device, a plate type heating device, a fluidized layer drying device, and a band. A mold drying device, a filtration drying device, a vibration flow drying device, an air flow drying device, a vacuum drying device, an infrared heating device, a far infrared heating device, a microwave heating device, and a high frequency drying device can be used.

In the heat treatment according to the present embodiment, for example, compound A is added to a thin sheet-shaped fiber raw material by a method such as impregnation and then heated, or the fiber raw material and compound A are heated while kneading or stirring with a kneader or the like. Can be adopted. This makes it possible to suppress uneven concentration of the compound A in the fiber raw material and more uniformly introduce the phosphoric acid group onto the surface of the cellulose fiber contained in the fiber raw material. This is because when the water molecules move to the surface of the fiber raw material due to drying, the dissolved compound A is attracted to the water molecules by the surface tension and also moves to the surface of the fiber raw material (that is, the concentration unevenness of the compound A is caused. It is considered that this is due to the fact that it can be suppressed.
Further, the heating device used for the heat treatment always keeps the water content retained by the slurry and the water content generated by the dehydration condensation (phosphoric acid esterification) reaction between the compound A and the hydroxyl group contained in the cellulose or the like in the fiber raw material. It is preferable that the device can be discharged to the outside. Examples of such a heating device include a ventilation type oven and the like. By constantly discharging the water in the apparatus system, it is possible to suppress the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the phosphate esterification, and also to suppress the acid hydrolysis of the sugar chain in the fiber. can. Therefore, it is possible to obtain fine fibrous cellulose having a high axial ratio.
The heat treatment time is, for example, preferably 1 second or more and 300 minutes or less, more preferably 1 second or more and 1,000 seconds or less after the water is substantially removed from the fiber raw material, and 10 seconds or more and 800. More preferably, it is less than a second. In the present embodiment, the amount of the phosphorus oxo acid group introduced can be within a preferable range by setting the heating temperature and the heating time within an appropriate range.

The phosphorus oxo acid group introduction step may be performed at least once, but may be repeated twice or more. By performing the phosphorus oxo acid group introduction step two or more times, many phosphorus oxo acid groups can be introduced into the fiber raw material. In the present embodiment, as an example of a preferable embodiment, there is a case where the phosphorus oxo acid group introduction step is performed twice.

The amount of the phosphorus oxo acid group introduced into the fiber raw material is, for example, 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.50 mmol / g / g per 1 g (mass) of fine fibrous cellulose. It is more preferably g or more, and particularly preferably 1.00 mmol / g or more. The amount of the phosphorus oxo acid group introduced into the fiber raw material is preferably 5.20 mmol / g or less, more preferably 3.65 mmol / g or less per 1 g (mass) of fine fibrous cellulose, for example. It is more preferably 00 mmol / g or less. By setting the amount of the phosphorus oxo acid group introduced within the above range, it is possible to facilitate the miniaturization of the fiber raw material and enhance the stability of the fine fibrous cellulose.

-Carboxy group introduction process-
The carboxy group introduction step has an oxidation treatment such as ozone oxidation, oxidation by the Fenton method, TEMPO oxidation treatment, a compound having a group derived from carboxylic acid or a derivative thereof, or a group derived from carboxylic acid with respect to the fiber raw material containing cellulose. This is done by treating with an acid anhydride of the compound or a derivative thereof.
The compound having a group derived from a carboxylic acid is not particularly limited, but for example, a dicarboxylic acid compound such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid, itaconic acid, citric acid, aconitic acid and the like. Examples include tricarboxylic acid compounds. The derivative of the compound having a group derived from a carboxylic acid is not particularly limited, and examples thereof include an imide of an acid anhydride of a compound having a carboxy group and a derivative of an acid anhydride of a compound having a carboxy group. The imide of the acid anhydride of the compound having a carboxy group is not particularly limited, and examples thereof include an imide of a dicarboxylic acid compound such as maleimide, succinateimide, and phthalateimide.

The acid anhydride of the compound having a group derived from a carboxylic acid is not particularly limited, but for example, a dicarboxylic acid compound such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. Acid anhydride can be mentioned. The derivative of the acid anhydride of the compound having a group derived from carboxylic acid is not particularly limited, but for example, a compound having a carboxy group such as dimethylmaleic acid anhydride, diethylmaleic acid anhydride, diphenylmaleic acid anhydride and the like. Examples thereof include those in which at least a part of the hydrogen atom of the acid anhydride is substituted with a substituent such as an alkyl group or a phenyl group.

When the TEMPO oxidation treatment is carried out in the carboxy group introduction step, it is preferable to carry out the treatment under conditions of pH 6 or more and 8 or less, for example. Such a treatment is also referred to as a neutral TEMPO oxidation treatment. Neutral TEMPO oxidation treatment includes, for example, sodium phosphate buffer (pH = 6.8), pulp as a fiber raw material, TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl) as a catalyst, and the like. This can be done by adding nitroxy radicals and sodium hypochlorite as a sacrificial reagent. Further, by coexisting with sodium chlorite, the aldehyde generated in the oxidation process can be efficiently oxidized to the carboxy group.
Further, the TEMPO oxidation treatment may be carried out under the condition that the pH is 10 or more and 11 or less. Such a treatment is also referred to as an alkaline TEMPO oxidation treatment. The alkaline TEMPO oxidation treatment can be carried out, for example, by adding a nitroxy radical such as TEMPO as a catalyst, sodium bromide as a co-catalyst, and sodium hypochlorite as an oxidizing agent to pulp as a fiber raw material. ..
The amount of carboxy group introduced into the fiber raw material varies depending on the type of substituent, but when a carboxy group is introduced by TEMPO oxidation, for example, it is preferably 0.10 mmol / g or more per 1 g (mass) of fine fibrous cellulose. , 0.20 mmol / g or more, more preferably 0.50 mmol / g or more, and particularly preferably 0.90 mmol / g or more. Further, it is preferably 2.5 mmol / g or less, more preferably 2.20 mmol / g or less, and further preferably 2.00 mmol / g or less. In addition, when the substituent is a carboxymethyl group, it may be 5.8 mmol / g or less per 1 g (mass) of fine fibrous cellulose.

-Sulfur oxoacid group introduction process-
The ionic substituent introduction step may include a sulfur oxoacid group introduction step. In the sulfur oxoacid group introduction step, a cellulose fiber having a sulfur oxoacid group (sulfur oxoacid group-introduced fiber) can be obtained by reacting the hydroxyl group of the fiber raw material containing cellulose with sulfur oxoacid.

In the sulfur oxoacid group introduction step, instead of compound A in the above-mentioned <phosphooxoacid group introduction step>, a compound capable of introducing a sulfur oxoacid group by reacting with a hydroxyl group of a fiber raw material containing cellulose is selected. At least one compound (hereinafter, also referred to as "Compound C") is used. The compound C may be any compound having a sulfur atom and capable of forming an ester bond with cellulose, and examples thereof include sulfuric acid or a salt thereof, sulfite or a salt thereof, and sulfate amide, but the compound C is not particularly limited. As the sulfuric acid, those having various puritys can be used, and for example, 96% sulfuric acid (concentrated sulfuric acid) can be used. Examples of sulfurous acid include 5% sulfurous acid water. Examples of the sulfate or sulfite include lithium salt, sodium salt, potassium salt, ammonium salt and the like of sulfate or sulfite, and these can have various neutralization degrees. As the sulfate amide, sulfamic acid or the like can be used. In the sulfur oxoacid group introduction step, it is preferable to use the compound B in the above-mentioned <phosphooxoacid group introduction step> in the same manner.

In the sulfur oxoacid group introduction step, it is preferable to mix the sulfur oxoacid and an aqueous solution containing urea and / or a urea derivative with the cellulose raw material, and then heat-treat the cellulose raw material. As the heat treatment temperature, it is preferable to select a temperature at which the sulfur oxoacid group can be efficiently introduced while suppressing the thermal decomposition and hydrolysis reaction of the fiber. The heat treatment temperature is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and even more preferably 150 ° C. or higher. The heat treatment temperature is preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and even more preferably 200 ° C. or lower.

In the heat treatment step, it is preferable to heat until the water content is substantially eliminated. Therefore, the heat treatment time varies depending on the amount of water contained in the cellulose raw material and the amount of the aqueous solution containing sulfur oxoacid and urea and / or a urea derivative, but is, for example, 10 seconds or more and 10000 seconds or less. It is preferable to do so. Equipment having various heat media can be used for the heat treatment, for example, a hot air drying device, a stirring drying device, a rotary drying device, a disk drying device, a roll type heating device, a plate type heating device, and a fluidized layer drying device. , Band type drying device, filtration drying device, vibration flow drying device, air flow drying device, vacuum drying device, infrared heating device, far infrared heating device, microwave heating device, high frequency drying device can be used.

The amount of the sulfur oxoacid group introduced into the cellulose raw material is preferably 0.05 mmol / g or more, more preferably 0.10 mmol / g or more, still more preferably 0.20 mmol / g or more. It is more preferably 0.40 mmol / g or more, and particularly preferably 0.50 mmol / g or more. The amount of sulfur oxoacid group introduced into the cellulose raw material is preferably 5.00 mmol / g or less, and more preferably 3.00 mmol / g or less. By setting the amount of the sulfur oxoacid group introduced within the above range, it is possible to facilitate the miniaturization of the cellulose fibers in the miniaturization treatment step and enhance the stability of the fine fibrous cellulose.

-Oxidation process with chlorine-based oxidant (second carboxy group introduction process)-
The ionic substituent introduction step may include an oxidation step with a chlorine-based oxidizing agent. In the oxidation step using a chlorine-based oxidant, a carboxy group is introduced into the fiber raw material by adding the chlorine-based oxidant to a wet or dry fiber raw material having a hydroxyl group and carrying out a reaction.

Examples of chlorine-based oxidizing agents include hypochlorite, hypochlorite, chloric acid, chlorite, chloric acid, chlorate, perchloric acid, perchlorate, chlorine dioxide and the like. From the viewpoint of introduction efficiency of substituents, defibration efficiency, cost, and ease of handling, the chlorine-based oxidizing agent is preferably sodium hypochlorite, sodium chlorite, or chlorine dioxide. When the chlorine-based oxidizing agent is added, it may be added as a reagent (solid or liquid) to the fiber raw material as it is, or it may be added by dissolving it in an appropriate solvent.

The concentration of the chlorine-based oxidant in the solution in the oxidation step using the chlorine-based oxidant is preferably 1% by mass or more and 1,000% by mass or less in terms of effective chlorine concentration, and is 5% by mass or more and 500% by mass or less. It is more preferably 10% by mass or more and 100% by mass or less. The amount of the chlorine-based oxidizing agent added to 100 parts by mass of the fiber raw material is preferably 1 part by mass or more and 100,000 parts by mass or less, more preferably 10 parts by mass or more and 10,000 parts by mass or less, and 100 parts by mass. It is more preferable that the amount is 5,000 parts by mass or more.

The reaction time with the chlorine-based oxidizing agent in the oxidation step using the chlorine-based oxidizing agent may vary depending on the reaction temperature, but is preferably 1 minute or more and 1,000 minutes or less, and is preferably 10 minutes or more and 500 minutes or less. More preferably, it is more preferably 20 minutes or more and 400 minutes or less. The pH at the time of the reaction is preferably 5 or more and 15 or less, more preferably 7 or more and 14 or less, and further preferably 9 or more and 13 or less. Further, at the start of the reaction, it is preferable that the pH during the reaction is kept constant (for example, pH 11) while appropriately adding hydrochloric acid or sodium hydroxide. After the reaction, excess reaction reagents, by-products and the like may be washed and removed by filtration or the like.

-Zantate group introduction step (xanthate esterification step)-
The ionic substituent introduction step may include, for example, a zantate group introduction step (hereinafter, also referred to as a zantate conversion step). In the zantate formation step, a zantate group is introduced into the fiber raw material by adding carbon disulfide and an alkaline compound to a wet or dry fiber raw material having a hydroxyl group and carrying out a reaction. Specifically, carbon disulfide is added to the alkali-cellulose-ized fiber raw material by the method described later, and the reaction is carried out.

<< Alkaline Cellulose >>
When introducing an ionic substituent into a fiber raw material, it is preferable to allow an alkaline solution to act on the cellulose contained in the fiber raw material to convert the cellulose into alkaline cellulose. By this treatment, a part of the hydroxyl groups of cellulose is ionically dissociated, and the nucleophilicity (reactivity) can be enhanced. The alkaline compound contained in the alkaline solution is not particularly limited, and may be an inorganic alkaline compound or an organic alkaline compound. For example, sodium hydroxide, potassium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide are preferably used because of their high versatility. Alkaline cellulosification may be carried out at the same time as the introduction of the ionic substituent, may be carried out as a pre-stage thereof, or may be carried out at both timings.

The solution temperature at the start of alkaline cellulose formation is preferably 0 ° C. or higher and 50 ° C. or lower, more preferably 5 ° C. or higher and 40 ° C. or lower, and further preferably 10 ° C. or higher and 30 ° C. or lower.

The alkali concentration in the alkaline solution is preferably 0.01 mol / L or more and 4 mol / L or less, more preferably 0.1 mol / L or more and 3 mol / L or less, and 1 mol / L or more 2 It is more preferably 5.5 mol / L or less. In particular, when the treatment temperature for alkali celluloseization is less than 10 ° C., the alkali concentration is preferably 1 mol / L or more and 2 mol / L or less.

The treatment time for alkali celluloseization is preferably 1 minute or longer, more preferably 10 minutes or longer, and even more preferably 30 minutes or longer. The alkali treatment time is preferably 6 hours or less, more preferably 5 hours or less, and even more preferably 4 hours or less.

By adjusting the type, treatment temperature, concentration, and immersion time of the alkaline solution as described above, the permeation of the alkaline solution into the crystalline region of cellulose can be suppressed, the crystalline structure of cellulose type I can be easily maintained, and the cellulose is in the form of fine fibers. The yield of cellulose can be increased.

When the introduction of the ionic substituent and the alkali celluloseization are not performed at the same time, the alkali celluloseization is preferably performed before the introduction of the ionic substituent. In this case, it is preferable that the alkali cellulose obtained by the alkali celluloseization treatment is solid-liquid separated to remove water by a general liquid removal method such as centrifugation or filtration. This improves the reaction efficiency in the subsequent ionic substituent introduction step. The cellulose fiber concentration after solid-liquid separation is preferably 5% or more and 50% or less, more preferably 10% or more and 40% or less, and further preferably 15% or more and 35% or less.

-Phosphon group or phosphine group introduction step (phosphoalkylation step)-
The ionic substituent introduction step may include a phosphon group or phosphine group introduction step (phosphoalkylation step). In the phosphoalkylation step, a compound having a reactive group and a phospho group or a phosphine group (Compound E _A ) as an essential component, an alkaline compound as an optional component, and a compound B selected from the above-mentioned urea and its derivatives are wetted. Alternatively, a phosphone group or a phosphine group is introduced into the fiber raw material by carrying out the reaction in addition to the fiber raw material having a hydroxyl group in a dry state.

Examples of the reactive group include an alkyl halide group, a vinyl group, an epoxy group (glycidyl group) and the like.
The compound E _A, e.g. vinyl phosphonic acid, phenyl vinyl phosphonic acid, and phenyl vinyl phosphinic acid. Introduction efficiency of substituents, and thus solution繊効rate, cost, compounds from the viewpoint of easy handling E _A is preferably vinylphosphonic acid.
Further, as an optional component, the compound B in the above-mentioned <phosphoric acid group introduction step> is also preferably used in the same manner, and the addition amount is preferably as described above.

When adding a compound E _A may be added directly to the fiber material as a reagent (solid or liquid), it may be added dissolved in a suitable solvent. It is preferable that the fiber raw material is made into alkali cellulose in advance or is made into alkali cellulose at the same time as the reaction. The method of alkali celluloseization is as described above.

The temperature during the reaction is, for example, preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower.

Amount for fiber material 100 parts by weight of Compound _{E A} is preferably not more than 100,000 parts by 1 part by mass or more, more preferably at most 10,000 parts by mass or more, 2 parts by mass 5 parts by weight It is more preferably 1,000 parts by mass or less.

The reaction time may vary depending on the reaction temperature, but is preferably 1 minute or more and 1,000 minutes or less, more preferably 10 minutes or more and 500 minutes or less, and 20 minutes or more and 400 minutes or less. Is even more preferable. After the reaction, excess reaction reagents, by-products and the like may be washed and removed by filtration or the like.

-Sulfone group introduction step (sulfoalkylation step) (second sulfone group introduction step)-
The ionic substituent introduction step may include a sulfone group introduction step (sulfoalkylation step). In sulfoalkylated, as essential components, a compound having a reactive group and a sulfonic group (Compound E _B), an alkaline compound as an optional component, a compound B which is selected from urea and its derivatives mentioned above, wet or dry By carrying out the reaction in addition to the fiber raw material having a hydroxyl group, a sulfone group is introduced into the fiber raw material.

Examples of the reactive group include an alkyl halide group, a vinyl group, an epoxy group (glycidyl group) and the like.
The compound E _B, 2-sodium chloroethane sulfonate, sodium vinyl sulfonate, p- sodium styrenesulfonate, 2-acrylamido-2-methylpropane sulfonic acid. Of these, the introduction efficiency of the substituents, and thus solution繊効rate, cost, vinyl compounds from the viewpoint of easy handling E _B is preferably a sodium sulfonate.
Further, as an optional component, the compound B in the above-mentioned <phosphoric acid group introduction step> is also preferably used in the same manner, and the addition amount is preferably as described above.

When adding the compound E _B may be added directly to the fiber material as a reagent (solid or liquid), it may be added dissolved in a suitable solvent. It is preferable that the fiber raw material is made into alkali cellulose in advance or is made into alkali cellulose at the same time as the reaction. The method of alkali celluloseization is as described above.

Amount for fiber material 100 parts by weight of compound _{E B} is preferably not more than 100,000 parts by 1 part by mass or more, more preferably at most 10,000 parts by mass or more, 2 parts by mass 5 parts by weight It is more preferably 1,000 parts by mass or less.

The reaction time may vary depending on the reaction temperature, but is preferably 1 minute or more and 1,000 minutes or less, more preferably 10 minutes or more and 500 minutes or less, and 15 minutes or more and 400 minutes or less. Is even more preferable. After the reaction, excess reaction reagents, by-products and the like may be washed and removed by filtration or the like.

-Carboxyalkylation step (third carboxy group introduction step)-
The ionic substituent introduction step may include a carboxyalkylation step. As essential components, a compound having a reactive group and a carboxy group (Compound E _C), alkaline compound as an optional component, a compound B which is selected from urea and its derivatives mentioned above, the wet or dry state, the fiber having a hydroxyl group By carrying out the reaction in addition to the raw material, a carboxy group is introduced into the fiber raw material.

Examples of the reactive group include an alkyl halide group, a vinyl group, an epoxy group (glycidyl group) and the like.
The compound E _C, introduction efficiency of the substituents, and thus solution繊効rate, cost, ease of handling monochloroacetic acid in terms of sodium monochloroacetate, 2-chloropropionic acid, 3-chloropropionic acid, sodium 2-chloropropionic acid , Sodium 3-chloropropionate is preferred.
Further, as an optional component, the compound B in the above-mentioned <phosphoric acid group introduction step> is also preferably used in the same manner, and the addition amount is preferably as described above.

When adding the compound E _C may be added directly to the fiber material as a reagent (solid or liquid), it may be added dissolved in a suitable solvent. It is preferable that the fiber raw material is made into alkali cellulose in advance or is made into alkali cellulose at the same time as the reaction. The method of alkali celluloseization is as described above.

Amount for fiber material 100 parts by weight of compound _{E C} is preferably not more than 100,000 parts by 1 part by mass or more, more preferably at most 10,000 parts by mass or more, 2 parts by mass 5 parts by weight It is more preferably 1,000 parts by mass or less.

The reaction time may vary depending on the reaction temperature, but is preferably 1 minute or more and 1,000 minutes or less, more preferably 3 minutes or more and 500 minutes or less, and 5 minutes or more and 400 minutes or less. Is even more preferable. After the reaction, excess reaction reagents, by-products and the like may be washed and removed by filtration or the like.

-Cationic group introduction step (cationization step)-
A compound having a reactive group and a cationic group (Compound _ED ) as an essential component, an alkaline compound as an optional component, and a compound B selected from the above-mentioned urea and its derivatives have a hydroxyl group in a wet or dry state. By carrying out the reaction in addition to the fiber raw material, a cationic group is introduced into the fiber raw material.

Examples of the reactive group include an alkyl halide group, a vinyl group, an epoxy group (glycidyl group) and the like.
Examples of the cationic group include an ammonium group, a phosphonium group, a sulfonium group and the like. Of these, the cationic group is preferably an ammonium group.
The compound E _D, introduction efficiency of the substituents, and thus solution繊効rate, cost, ease of handling glycidyl trimethyl ammonium chloride from the viewpoint of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride are preferred.
Further, as an optional component, it is also preferable to similarly use the compound B in the above-mentioned <phosphoric acid group introduction step>. The amount of addition is also preferably as described above.

When adding the compound E _D may be added directly to the fiber material as a reagent (solid or liquid), it may be added dissolved in a suitable solvent. It is preferable that the fiber raw material is made into alkali cellulose in advance or is made into alkali cellulose at the same time as the reaction. The method of alkali celluloseization is as described above.

Amount for fiber material 100 parts by weight of Compound _{E D} is preferably not more than 100,000 parts by 1 part by mass or more, more preferably at most 10,000 parts by mass or more, 2 parts by mass 5 parts by weight It is more preferably 1,000 parts by mass or less.

The reaction time may vary depending on the reaction temperature, but is preferably 1 minute or more and 1,000 minutes or less, more preferably 5 minutes or more and 500 minutes or less, and 10 minutes or more and 400 minutes or less. Is even more preferable. After the reaction, excess reaction reagents, by-products and the like may be washed and removed by filtration or the like.

<Washing process>
In the step of obtaining the cellulose fiber having an ionic substituent, a washing step can be performed on the ionic substituent-introduced fiber, if necessary. The washing step is performed by washing the ionic substituent-introduced fiber with, for example, water or an organic solvent. Further, the cleaning step may be performed after each step described later, and the number of cleanings performed in each cleaning step is not particularly limited.

<Alkaline treatment process>
In the step of obtaining the cellulose fiber having an ionic substituent, an alkali treatment step may be provided between the ionic substituent introduction step and the miniaturization treatment step. The alkaline treatment method is not particularly limited, and examples thereof include a method of immersing the ionic substituent-introduced fiber in an alkaline solution.

The alkaline compound contained in the alkaline solution is not particularly limited, and may be an inorganic alkaline compound or an organic alkaline compound. In the present embodiment, for example, sodium hydroxide or potassium hydroxide is preferably used as the alkaline compound because of its high versatility. Further, the solvent contained in the alkaline solution may be either water or an organic solvent. Among them, the solvent contained in the alkaline solution is preferably a polar solvent containing water or a polar organic solvent exemplified by alcohol, and more preferably an aqueous solvent containing at least water. As the alkaline solution, for example, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is preferable because of its high versatility.

The temperature of the alkaline solution in the alkaline treatment step is not particularly limited, but is preferably 5 ° C. or higher and 80 ° C. or lower, and more preferably 10 ° C. or higher and 60 ° C. or lower. The immersion time of the ionic substituent-introduced fiber in the alkaline solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes or more and 30 minutes or less, and more preferably 10 minutes or more and 20 minutes or less. The amount of the alkaline solution used in the alkaline treatment is not particularly limited, but is preferably 100% by mass or more and 100,000% by mass or less, and 1000% by mass or more and 10000% by mass or less, based on the absolute dry mass of the ionic substituent-introduced fiber. The following is more preferable.

In order to reduce the amount of the alkaline solution used in the alkali treatment step, the ionic substituent introduction fiber may be washed with water or an organic solvent after the ionic substituent introduction step and before the alkali treatment step. After the alkali treatment step and before the miniaturization treatment step, it is preferable to wash the alkali-treated ionic substituent-introduced fiber with water or an organic solvent from the viewpoint of improving handleability.

<Acid treatment process>
In the step of obtaining the cellulose fiber having an ionic substituent, an acid treatment step may be provided between the ionic substituent introduction step and the miniaturization treatment step. For example, the ionic substituent introduction step, the acid treatment, the alkali treatment, and the micronization treatment may be performed in this order.

The acid treatment method is not particularly limited, and examples thereof include a method of immersing the fiber raw material in an acidic liquid containing an acid. The concentration of the acidic liquid used is not particularly limited, but is preferably, for example, 10% by mass or less, and more preferably 5% by mass or less. The pH of the acidic liquid used is not particularly limited, but is preferably 0 or more and 4 or less, and more preferably 1 or more and 3 or less. As the acid contained in the acidic liquid, for example, an inorganic acid, a sulfonic acid, a carboxylic acid or the like can be used. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chloric acid, chloric acid, perchloric acid, phosphoric acid, boric acid and the like. Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and the like. Examples of the carboxylic acid include formic acid, acetic acid, citric acid, gluconic acid, lactic acid, oxalic acid, tartaric acid and the like. Among these, it is particularly preferable to use hydrochloric acid or sulfuric acid.

The temperature of the acid solution in the acid treatment is not particularly limited, but is preferably 5 ° C. or higher and 100 ° C. or lower, and more preferably 20 ° C. or higher and 90 ° C. or lower. The immersion time in the acid solution in the acid treatment is not particularly limited, but is preferably 5 minutes or more and 120 minutes or less, and more preferably 10 minutes or more and 60 minutes or less. The amount of the acid solution used in the acid treatment is not particularly limited, but is preferably 100% by mass or more and 100,000% by mass or less, and 1000% by mass or more and 10,000% by mass or less, for example, with respect to the absolute dry mass of the fiber raw material. Is more preferable.

(Defibration processing process)
Fine fibrous cellulose can be obtained by defibrating the ionic group-introduced fiber in the defibration treatment step.
In the defibration treatment step, for example, a defibration treatment apparatus can be used. The defibrating apparatus is not particularly limited, but for example, a high-speed defibrator, a grinder (stone mill type crusher), a high-pressure homogenizer or an ultra-high pressure homogenizer, a high-pressure collision type crusher, a ball mill, a bead mill, a disc type refiner, a conical refiner, and a twin shaft. A kneader, a vibration mill, a homomixer under high speed rotation, an ultrasonic disperser, or a beater can be used. Among the above-mentioned defibration processing devices, it is more preferable to use a high-speed defibrator, a high-pressure homogenizer, and an ultra-high-pressure homogenizer, which are less affected by crushed media and less likely to cause contamination.

In the defibration treatment step, for example, it is preferable to dilute the ionic group-introduced fiber with a dispersion medium to form a slurry. As the dispersion medium, one or more selected from water and an organic solvent such as a polar organic solvent can be used. The polar organic solvent is not particularly limited, but for example, alcohols, polyhydric alcohols, ketones, ethers, esters, aprotic polar solvents and the like are preferable. Examples of alcohols include methanol, ethanol, isopropanol, n-butanol, isobutyl alcohol and the like. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin and the like. Examples of the ketones include acetone, methyl ethyl ketone (MEK) and the like. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monon-butyl ether, propylene glycol monomethyl ether and the like. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the aprotonic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP) and the like.

The solid content concentration of the fine fibrous cellulose during the defibration treatment can be appropriately set.
Further, the slurry obtained by dispersing the phosphorus oxo acid group-introduced fiber in a dispersion medium may contain a solid content other than the phosphorus oxo acid group-introduced fiber such as urea having a hydrogen bond property.

The content of fine fibrous cellulose in the solid content of the radiation-sensitive sheet is preferably 5% by mass or more, more preferably 15 from the viewpoint of enabling the transparency of the radiation-sensitive sheet and the formation of fine patterns. Mass% or more, more preferably 25% by mass or more, still more preferably 35% by mass or more, and preferably 85% by mass or less, more preferably 75% by mass or less, still more preferably 65% by mass or less, still more. It is preferably 55% by mass or less.
As the fine fibrous cellulose, fine fibrous cellulose containing an ionic group described later and unmodified fine fibrous cellulose may be used in combination.

<Hydrophilic polymer>
The radiation-sensitive sheet of the present embodiment contains a hydrophilic polymer. The hydrophilic polymer means a polymer compound having a solubility of 1 g or more in 100 ml of ion-exchanged water at 25 ° C. under normal pressure and having a weight average molecular weight of 5,000 or more.
The hydrophilic polymer excludes the resin for a radiation-sensitive composition described later, and its solubility in a solvent is greatly changed by acids and radicals generated by irradiation of the radiation-sensitive compound with radiation. It does not have an acid-degradable group or a radically polymerizable group.

The hydrophilic polymer is preferably a hydrophilic oxygen-containing organic compound (however, the above-mentioned cellulose fibers are excluded). The hydrophilic oxygen-containing organic compound preferably has an SP value of, for example, 9.0 or more.
Examples of the hydrophilic polymer used in the present embodiment include polyalkylene glycol (polyethylene glycol, polypropylene glycol, etc.), cellulose derivatives (hydroxyethyl cellulose, carboxyethyl cellulose, carboxymethyl cellulose, etc.), casein, dextrin, starch, modified starch, polyvinyl. Alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol, ethylene-vinyl alcohol copolymer, ethylene oxide polyvinyl alcohol, etc.), polyalkylene oxide (polyethylene oxide, etc.), polyvinylpyrrolidone, polyvinylmethyl ether, polyacrylates, polyacrylamide , Acrylic acid alkyl ester copolymer, urethane-based copolymer and the like. Among the above, it is particularly preferable to use polyethylene glycol, polyethylene oxide, polyvinyl alcohol, and modified polyvinyl alcohol.

The weight average molecular weight of the hydrophilic polymer is not particularly limited as long as it is 5,000 or more, but is preferably 10,000 or more from the viewpoint of shape stability of the radiation-sensitive sheet and enabling fine patterning. It is preferably 15,000 or more, more preferably 20,000 or more. The weight average molecular weight of the hydrophilic polymer is preferably 8 million or less, more preferably 5 million or less, still more preferably 1 million or less, and even more preferably 100,000 or less.
The weight average molecular weight can be measured using, for example, GPC.

The content of the hydrophilic polymer in the radiation-sensitive sheet is 10 parts by mass or more with respect to 100 parts by mass of the solid content of the fine fibrous cellulose from the viewpoint of enabling shape stability and fine patterning of the radiation-sensitive sheet. It is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, and preferably 250 parts by mass or less, more preferably 150 parts by mass or less, still more preferably 100 parts by mass. It is less than a part, more preferably 50 parts by mass or less.
The content of the hydrophilic polymer in the radiation-sensitive sheet is preferably 25 parts by mass or more with respect to 100 parts by mass of the radiation-sensitive composition from the viewpoint of shape stability of the radiation-sensitive sheet and enabling fine patterning. And preferably 70 parts by mass or less.

Further, the content of the hydrophilic polymer in the solid content of the radiation-sensitive sheet is preferably 1% by mass or more, more preferably 5 from the viewpoint of enabling shape stability and fine patterning of the radiation-sensitive sheet. By mass% or more, more preferably 10% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 50% by mass or less, still more preferably 40% by mass or less, still more. It is preferably 30% by mass or less.

<Radiation-sensitive composition>
The radiation-sensitive sheet of the present embodiment contains a radiation-sensitive composition. Depending on the type of the radiation-sensitive composition, the radiation-sensitive sheet of the present embodiment may be a positive-type radiation-sensitive sheet or a negative-type radiation-sensitive sheet.
The radiation-sensitive composition comprises a radiation-sensitive compound and a resin for the radiation-sensitive composition (hereinafter, also referred to as “radiation-sensitive resin”). The resin for a radiation-sensitive composition increases or decreases its solubility in a solvent due to the radiation-irradiated radiation-sensitive compound. That is, it has the property of polymerizing, cross-linking, and / or decomposing by the action of reactive active species such as acids and radicals generated from radiation-sensitive compounds by irradiation. The radiation-sensitive compound imparts radiation-sensitive properties to the radiation-sensitive composition.
A radiation-sensitive compound is a compound that produces a reactive active species upon exposure to radiation. Here, the radiation includes at least visible light, ultraviolet rays, far ultraviolet rays, electron beams (charged particle beams) and X-rays. Among these, ultraviolet rays are preferable. As the radiation-sensitive compound, an acid generator, a polymerization initiator, or a combination thereof is preferable. When an acid generator is used, it can be either a positive type or a negative type radiation-sensitive composition depending on other additive components. When a quinonediazide compound is used, a positive radiation-sensitive composition can be obtained. On the other hand, when a polymerization initiator is used, a negative type radiation-sensitive composition can be obtained.

[Resin for radiation sensitive composition]
The resin for a radiation-sensitive composition (radiation-sensitive resin) includes, in addition to a compound generally called a polymer, a so-called oligomer and a monomer having a lower molecule.
That is, the radiation-sensitive resin is a compound whose solubility in a solvent is increased or decreased by a reaction induced by a reactive active species such as an acid or a radical generated from the radiation-sensitive compound by irradiation. If there is, there is no particular limitation.

When the radiation-sensitive resin is a polymer compound, the skeleton structure thereof includes, for example, polyalkylene glycol (polyethylene glycol, polypropylene glycol, etc.), cellulose derivatives (hydroxyethyl cellulose, carboxyethyl cellulose, carboxymethyl cellulose, etc.), casein, and the like. Dextrin, polyvinyl alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol, ethylene-vinyl alcohol copolymer, ethylene oxide polyvinyl alcohol, etc.), polyalkylene oxide (polyethylene oxide, etc.), polyvinylpyrrolidone, polyvinylmethyl ether, polyacrylic acid salts, etc. , Polyacrylamide, acrylic acid ester copolymer, urethane-based copolymer, polyhydroxystyrene-based copolymer, and the like. Among the above, it is particularly preferable to use a structure containing polyethylene glycol, polyethylene oxide, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylamide, and an acrylic acid ester copolymer.
When the radiation-sensitive resin is a polymer, in addition to the above-mentioned skeleton structure, it is preferable to have an acidic hydroxyl group or an acid dissociative group in the case of the positive type, and in the case of the negative type, it is preferable to have an acid dissociative group. It preferably has a radically polymerizable group or a hetero-membered ring group.

As described above, the radiation-sensitive resin used for the positive-type radiation-sensitive sheet preferably has an acidic hydroxyl group or an acid dissociative group in addition to the above-mentioned skeletal structure.
Examples of the acidic hydroxyl group include a phenolic hydroxyl group such as a hydroxyaryl group and a carboxy group, and the combined use with a quinonediazide compound as a radiation-sensitive compound is particularly preferable. For example, when a part of the radiation-sensitive sheet is irradiated with radiation, the acid hydroxyl group and the quinonediazide compound can interact with each other in the non-irradiated sheet portion to suppress the solubility in a developing solution or the like. On the other hand, the irradiated portion (exposed portion) loses its interaction with the acidic hydroxyl group due to the photoreaction of the quinonediazide compound, and its solubility in a developing solution or the like can be improved. That is, the radiation-sensitive sheet can usually exhibit a positive radiation-sensitive property.
Examples of the acid dissociable group include a tertiary alkyl ester group, a tert-butoxycarbonyl group, an acetal group and the like, and examples of the radiosensitive compound include an oxime sulfonate compound, an onium salt such as triarylsulfonium and diaryliodonium, and the like. It is particularly preferable to use it in combination with a photoacid generator such as a sulfonimide compound. For example, when a part of the radiation-sensitive sheet is irradiated with radiation, the non-irradiated sheet portion is suppressed from being soluble in a developer or the like by a tertiary alkyl ester group, a tert-butoxycarbonyl group, an acetal group, or the like. be able to. On the other hand, the irradiated portion (exposed portion) is developed by deprotecting the tertiary alkyl ester group, tert-butoxycarbonyl group, acetal group, etc. that protected the hydroxyl group by the acid generated by the photoreaction of the photoacid generator. Solubility in liquids and the like can be increased. That is, the radiation-sensitive sheet can usually exhibit a positive radiation-sensitive property.

As described above, the radiation-sensitive resin used for the negative-type radiation-sensitive sheet preferably contains a hetero-small ring group or a polymerizable unsaturated group in addition to the above-mentioned skeletal structure.
Examples of the hetero-membered ring group include an epoxy group and an oxetane group, and as a radiation-sensitive compound, it is particularly preferable to use it in combination with a photoacid generator.
For example, when a part of the radiation-sensitive sheet is irradiated with radiation, the cross-linking reaction through the ring-opening of the reactive hetero-membered ring functional group such as an epoxy group does not proceed in the non-irradiated sheet portion, so that the developing solution High solubility in etc. On the other hand, in the irradiated portion (exposed portion), the acid generated by the photoreaction of the photoacid generator, which is a radiation-sensitive compound, catalyzes the cross-linking reaction through the opening of the reactive hetero-membered ring group, and is applied to the developing solution and the like. Solubility can be suppressed. That is, the radiation-sensitive sheet can usually exhibit a negative type radiation-sensitive property.
Examples of the polymerizable unsaturated group include an acryloyl group and a methacryloyl group, and as a radiation-sensitive compound, it is particularly preferable to use it in combination with a photopolymerization initiator.
For example, when a part of the radiation-sensitive sheet is irradiated with radiation, the cross-linking reaction through the polymerization of a polymerizable unsaturated group such as an acryloyl group does not proceed in the non-irradiated sheet portion, so that the sheet portion is soluble in a developing solution or the like. Is expensive. On the other hand, in the irradiated portion (exposed portion), radicals generated by the photoreaction of the photopolymerization initiator can catalyze the cross-linking reaction through the polymerization of the polymerizable unsaturated group, and the solubility in a developing solution or the like can be suppressed. That is, the radiation-sensitive sheet can usually exhibit a negative type radiation-sensitive property.

When the radiation-sensitive sheet is a negative type, an oligomer or a monomer having a lower molecular weight may be used as the radiation-sensitive resin.
In particular, as the oligomer or monomer, an oligomer or monomer having a polymerizable unsaturated group (hereinafter, these are collectively referred to as "polymerizable unsaturated compound") is preferable.
The polymerizable unsaturated compound is an unsaturated compound that is polymerized by irradiating the radiation-sensitive sheet with radiation in the presence of the radiation-sensitive compound in the radiation-sensitive composition. Such a polymerizable unsaturated compound is not particularly limited, but for example, a bifunctional or trifunctional or higher polyfunctional (meth) acrylic acid ester has good polymerizable property and is formed. This is preferable because the strength of the radiation-sensitive sheet is improved.

Examples of the bifunctional (meth) acrylic acid ester include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol diacrylate, and tetraethylene glycol di (meth). Examples thereof include acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol di (meth) acrylate. These commercially available products include, for example, Aronix (registered trademark) M-210, M-240, M-6200 (all manufactured by Toa Synthetic Co., Ltd.), KAYARAD (registered trademark) HDDA, and HX. -220, R-604 (above, manufactured by Nippon Kayaku Co., Ltd.), Viscort 260, 312, 335HP (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light Acrylate 1,9-NDA (Kyoeisha Chemical Co., Ltd.) (Manufactured) and the like.

Examples of the trifunctional or higher functional (meth) acrylic acid ester include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol penta (meth) acrylate. Dipentaerythritol hexa (meth) acrylate;
Mixture of dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate;
Ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, tri (2- (meth) acryloyloxyethyl) phosphate, succinic acid-modified pentaerythritol tri (meth) acrylate, succinic acid-modified dipentaerythritol penta (meth) acrylate, tripenta A mixture of erythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, isocyanuric acid EO-modified diacrylate and isocyanuric acid EO-modified triacrylate;

Further, as a polyfunctional (meth) acrylic acid ester, a compound having a linear alkylene group and an acryloyl structure and having two or more isocyanate groups, and having one or more hydroxyl groups in the molecule and having a hydroxyl group in the molecule, and Examples thereof include a polyfunctional urethane acrylate compound obtained by reacting with a compound having 3, 4, or 5 (meth) acryloyloxy groups.
Commercially available products of the above-mentioned trifunctional or higher functional (meth) acrylic acid ester have trade names such as Aronix (registered trademark) M-309, M-400, M-405, M-450, and M. -7100, M-8030, M-8060, TO-1450 (all manufactured by Toa Synthetic Co., Ltd.), KAYARAD (registered trademark) TMPTA, DPHA, DPCA-20, DPCA-30, DPCA- 60, DPCA-120, DPEA-12 (above, manufactured by Nippon Kayaku Co., Ltd.), Viscort 295, 300, 360, GPT, 3PA, 400 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.) As commercial products containing polyfunctional urethane acrylate compounds, New Frontier (registered trademark) R-1150 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), KAYARAD (registered trademark) DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.) And so on.

Of these, among these, 1,9-nonanediol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate;
Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate;
Mixture of tripentaerythritol hepta (meth) acrylate and tripentaerythritol octa (meth) acrylate;
Ethylene oxide-modified dipentaerythritol hexaacrylate, polyfunctional urethane acrylate-based compounds, succinic acid-modified pentaerythritol triacrylate, succinic acid-modified dipentaerythritol pentaacrylate; and commercially available products containing these are preferable.
The polyfunctional polymerizable unsaturated compound as described above can be used alone or in combination of two or more.

The molecular weight of the radiation-sensitive resin (weight average molecular weight when it has a molecular weight distribution) is not particularly limited, but from the viewpoint of enabling fine patterning, it may be 200 or more, preferably 300 or more, and 500 or more. The above is more preferable. The molecular weight (weight average molecular weight) of the radiation-sensitive resin is preferably 100,000 or less, and more preferably 10,000 or less.
The weight average molecular weight can be measured using, for example, GPC.

<Radiation-sensitive compounds>
In the present embodiment, the radiation-sensitive composition preferably contains at least one of a photoacid generator and a photopolymerization initiator as the radiation-sensitive compound.
[Photoacid generator]
A photoacid generator (also simply referred to as an "acid generator") is a compound that generates an acid upon irradiation with radiation. By containing the acid generator, the radiation-sensitive composition of the present embodiment can exhibit, for example, positive radiation-sensitive characteristics with respect to an alkaline developer. The acid generator is not particularly limited as long as it is a compound that generates an acid (for example, carboxylic acid, sulfonic acid, etc.) by irradiation with radiation. Examples of the acid generator include an oxime sulfonate compound, an onium salt, a sulfonimide compound, a quinonediazide compound and the like, and may be used alone or in combination of two or more.

Examples of oxime sulfonate compounds include, for example, (5-propylsulfonyloxyimine-5H-thiophene-2-iriden)-(2-methylphenyl) acetonitrile, (5-octylsulfonyloxyimine-5H-thiophene-2-iriden). -(2-Methylphenyl) acetonitrile, (Camfersulfonyloxyimine-5H-thiophene-2-iriden)-(2-Methylphenyl) acetonitrile, (5-p-toluenesulfonyloxyimine-5H-thiophene-2-iriden) Examples thereof include- (2-methylphenyl) acetonitrile and 2- (octylsulfonyloxyimino) -2- (4-methoxyphenyl) acetonitrile.
Examples of onium salts include, for example, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzene benzene sulfonate, diphenyliodonium nonafluoro n-butane sulfonate, bis (4-t-butylphenyl) iodonium trifluoromethane sulfonate, bis ( 4-t-butylphenyl) iodonium dodecylbenzenesulfonate, bis (4-t-butylphenyl) iodonium naphthalene sulfonate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate, bis (4-t-butylphenyl) iodonium Nonafluoro n-butane sulfonate, diphenyliodonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalene sulfonate, triphenylsulfonium nonafluoro-n-butane sulfonate, (hydroxyphenyl) Benzenemethylsulfonium toluenesulfonate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, dicyclohexyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, dimethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, triphenylsulfonium camphorsulfonate, ( 4-Hydroxyphenyl) benzylmethyl sulfonium toluene sulfonate, 1-naphthyl dimethyl sulfonium trifluoromethane sulfonate, 1-naphthyl dimethyl sulfonium "1-naphthyl dimethyl" in trifluoromethane sulfonate is 1-naphthyl diethyl, 4-cyano-1-naphthyl dimethyl, 4-Nitro-1-naphthyldimethyl, 4-methyl-1-naphthyldimethyl, 4-cyano-1-naphthyl-diethyl, 4-nitro-1-naphthylditoluene, 4-methyl-1-naphthyldiethyl, 4-hydroxy- Examples include compounds that replace 1-naphthyldimethyl.

Examples of sulfonimide compounds include, for example, N- (trifluoromethylsulfonyloxy) succinimide, N- (kanfasulfonyloxy) succinimide, N- (4-methylphenylsulfonyloxy) succinimide, N- (2-trifluoromethylphenyl). Sulfonyloxy) Sulfonylimide, N- (4-fluorophenylsulfonyloxy) Sulfonylimide, N- (trifluoromethylsulfonyloxy) phthalimide, N- (kanfasulfonyloxy) phthalimide, N- (2-trifluoromethylphenylsulfonyloxy) phthalimide , N- (2-fluorophenylsulfonyloxy) phthalimide, N- (trifluoromethylsulfonyloxy) diphenylmaleimide, N- (kanfasulfonyloxy) diphenylmaleimide, N-hydroxynaphthalimide-trifluoromethanesulfonic acid ester and the like. ..

Examples of the quinone diazide compound include 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 2,3,4-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4. 2', 4'-pentahydroxybenzophenone, tris (4-hydroxyphenyl) methane, tris (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenyl ethane, 1,3-bis [1- (4-Hydroxyphenyl) -1-methylethyl] benzene, 1,4-bis [1- (4-hydroxyphenyl) -1-methylethyl] benzene, 4,6-bis [1- (4- (4-)4-bis] Hydroxyphenyl) -1-methylethyl] -1,3-dihydroxybenzene, 1,1-bis (4-hydroxyphenyl) -1- [4- {1- (4-hydroxyphenyl) -1-methylethyl} phenyl ] Etan, 4,4'-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] Bisphenol and other compounds having one or more phenolic hydroxyl groups, and 1, Examples thereof include an ester compound with 2-naphthoquinone diazide-4-sulfonic acid or 1,2-naphthoquinone diazide-5-sulfonic acid.

When the radiation-sensitive sheet contains a photoacid generator, for example, when a part of the radiation-sensitive sheet is irradiated with radiation, the solubility of the irradiated portion (exposed portion) in a developing solution or the like can be improved. can. That is, the radiation-sensitive sheet can usually exhibit a positive radiation-sensitive property.
The content of the photoacid generator of the present embodiment is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, and preferably 30 parts by mass with respect to 100 parts by mass of the radiation-sensitive resin. Hereinafter, it is more preferably 20 parts by mass or less. When the content of the photoacid generator with respect to the radiation-sensitive resin is within the above range, excellent radiation-sensitive properties can be imparted.

[Photopolymerization initiator]
A photopolymerization initiator (hereinafter, also simply referred to as “polymerization initiator”) is a component that produces an active species capable of initiating the polymerization of a polymerizable compound in response to radiation. By containing the polymerization initiator, the radiation-sensitive composition of the present embodiment can exhibit, for example, negative-type radiation-sensitive characteristics with respect to an alkaline developer. Examples of the photopolymerization initiator include a photoradical polymerization initiator. The photopolymerization initiator can initiate a cross-linking reaction of a compound having a polymerizable group by exposure to radiation such as visible light, ultraviolet rays, far ultraviolet rays, electron beams, and X-rays, and is preferably used. The agent is, for example, a photopolymerization initiator that generates the most radicals in the vicinity of ultraviolet rays, particularly 365 nm.
Examples of the photoradical polymerization initiator include an O-acyloxime compound, an acetophenone compound, a biimidazole compound, an acylphosphine oxide compound and the like. These compounds may be used alone or in admixture of two or more.

Examples of the O-acyloxime compound include 1- [4- (phenylthio) -2- (O-benzoyloxime)] and 1,2-octanedione-1- [4- (phenylthio) -2- (O-). Benzoyl oxime)], Etanone-1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl] -1- (O-acetyloxime), 1- [9-ethyl-6- Benzoyl-9. H. -Carbazole-3-yl] -octane-1-one oxime-O-acetate, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazole-3-yl] -ethane-1-one oxime-O-benzoate, 1- [9-n-butyl-6- (2-ethylbenzoyl) -9. H. -Carbazole-3-yl] -ethane-1-one oxime-O-benzoate, ethane-1- [9-ethyl-6- (2-methyl-4-tetrahydrofuranylbenzoyl) -9. H. -Carbazole-3-yl] -1- (O-acetyloxime), Etanone-1- [9-ethyl-6- (2-methyl-4-tetrahydropyranylbenzoyl) -9. H. -Carbazole-3-yl] -1- (O-acetyloxime), Etanone-1- [9-ethyl-6- (2-methyl-5-tetrahydrofuranylbenzoyl) -9. H. -Carbazole-3-yl] -1- (O-acetyloxime), ethanone-1- [9-ethyl-6- {2-methyl-4- (2,2-dimethyl-1,3-dioxolanyl) methoxybenzoyl) } -9. H. -Carbazole-3-yl] -1- (O-acetyloxime) and the like can be mentioned.

Examples of the acetophenone compound include an α-aminoketone compound and an α-hydroxyketone compound.
Examples of the α-aminoketone compound include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1-one and 2-dimethylamino-2- (4-methylbenzyl) -1- (4). -Morpholine-4-yl-phenyl) -butane-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one and the like can be mentioned.
Examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one and 1- (4-i-propylphenyl) -2-hydroxy-2-methylpropan-1-one. , 4- (2-Hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, 2-hydroxy-1-{4- [2- (2-hydroxyethoxy) ethoxy] phenyl } -2-Methylpropan-1-one, 2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone and the like.

Examples of the biimidazole compound include 2,2'-bis (2-chlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole and 2,2'-bis (2,). 4-Dichlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4', 5, Examples thereof include 5'-tetraphenyl-1,2'-biimidazole.
Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide, and lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate. And so on.

By including the photopolymerization initiator in the radiation-sensitive sheet, for example, when a part of the radiation-sensitive sheet is irradiated with radiation, the solubility of the irradiated portion (exposed portion) in a developing solution or the like can be reduced. Can be done. That is, the radiation-sensitive sheet can usually exhibit a negative type radiation-sensitive property.

The content of the photopolymerization initiator in the radiation-sensitive composition of the present embodiment is preferably 1 part by mass or more, more preferably 5 parts by mass or more, based on 100 parts by mass of the radiation-sensitive resin, and It is preferably 40 parts by mass or less, more preferably 20 parts by mass or less. By using a photopolymerization initiator in this range, excellent radiation sensitivity can be imparted. Further, by setting the content of the photopolymerization initiator in such a range, the radiation-sensitive sheet containing the radiation-sensitive composition of the present embodiment has a negative radiation-sensitive radiation even at a low exposure amount. Can express sex.

The content of the radiation-sensitive composition in the solid content of the radiation-sensitive sheet is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass, from the viewpoint of enabling fine patterning. It is more than 80% by mass, more preferably 70% by mass or less, still more preferably 60% by mass or less.

The radiation sensitive composition is preferably dissolved in water, alcohol, or at least one of a mixed solvent thereof. This is preferable because it facilitates the coating or papermaking process described later.
When the radiation-sensitive composition is dissolved in water, alcohol, or at least one of a mixed solvent thereof, the radiation-sensitive composition is water, an alcohol having 1 or more and 6 or less carbon atoms (preferably 1 carbon atom). Alcohol with 4 or more carbon atoms, more preferably alcohol with 1 or more carbon atoms and 3 or less carbon atoms), or 1 g of water and 100 g of a mixed solvent of alcohol with 1 or more carbon atoms and 6 or less carbon atoms at 25 ° C. and atmospheric pressure. It means that it dissolves.
In addition, since the radiation-sensitive composition is dissolved in at least one of water, alcohol, or a mixed solvent, it has a high affinity for fine fibrous cellulose and a hydrophilic polymer, and is a uniform coating liquid or slurry for papermaking. Is preferable because it can be prepared.

Further, from the viewpoint of making a radiation-sensitive composition that dissolves in water, alcohol, or at least one of these mixed solvents, the radiation-sensitive sheet of the present embodiment is preferably a negative type. By using a negative type radiation-sensitive sheet, a low-molecular-weight and hydrophilic monomer or oligomer can be selected as the radiation-sensitive resin, and a radiation-sensitive composition that dissolves in water, alcohol, or a mixed solvent thereof. Can be.

<Other ingredients>
In addition to the above-mentioned fine fibrous cellulose, hydrophilic polymer, resin for radiation-sensitive composition, radiation-sensitive compound, acid generator, and photopolymerization initiator, the radiation-sensitive sheet of the present embodiment contains other components. May be contained.
Other components include monofunctional polymerizable unsaturated compounds, wet paper strength enhancers, organic ions, cross-linking agents, surfactants, coupling agents, inorganic layered compounds, inorganic compounds, leveling agents, preservatives, defoamers. , Organic particles, lubricants, antistatic agents, UV absorbers, dyes, pigments, stabilizers, magnetic powders, orientation promoters, plasticizers, and dispersants.

Examples of the monofunctional (meth) acrylic acid ester include 2-hydroxyethyl (meth) acrylate, diethylene glycol monoethyl ether (meth) acrylate, (2- (meth) acryloyloxyethyl) (2-hydroxypropyl) phthalate, and the like. Examples thereof include ω-carboxypolycaprolactone mono (meth) acrylate. These commercially available products include, for example, Aronix (registered trademark) M-101, M-111, M-114, M-5300 (all manufactured by Toa Synthetic Co., Ltd.); KAYARAD (registered trademark). ) TC-110S, TC-120S (above, manufactured by Nippon Kayaku Co., Ltd.); Viscort 158, 2311 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.) and the like.

Wet paper strength enhancer is a chemical that suppresses the decrease in paper strength when the paper gets wet, and by adding it to pulp fibers that are easily loosened by water, the pulp fibers are bound even when wet with water. Has the effect of holding and making it difficult to loosen and increasing the strength.
Examples of the wet paper strength enhancer include polyamine polyamide epihalohydrin, melamine formaldehyde resin, and urea formaldehyde resin.
Polyamine polyamide epichlorohydrin is synthesized, for example, by adding epichlorohydrin to the main chain obtained by condensing a polyhydric acid and polyethylene polyamine. Polyamine polyamide epiclohydrin can be used in a wide pH range, and a high wet paper strength enhancing effect can be obtained with a low addition amount.
Melamine formaldehyde resin is synthesized by adding formaldehyde to melamine and then acid-condensing it.
Further, the urea formaldehyde resin is synthesized by adding formaldehyde to urea and then partially cross-linking the resin.
Among these, it is preferable to use polyamine polyamide epihalohydrin from the viewpoint of obtaining a sheet having low water absorption and linear thermal expansion and excellent transparency. Among the polyamine polyamide epichlorohydrins, the polyamine polyamide epichlorohydrin is more preferable.

Examples of organic ions include tetraalkylammonium ions and tetraalkylphosphonium ions. Examples of the tetraalkylammonium ion include tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrahexylammonium ion, tetraheptylammonium ion, tributylmethylammonium ion, and lauryltrimethyl. Examples thereof include ammonium ion, cetyltrimethylammonium ion, stearyltrimethylammonium ion, octyldimethylethylammonium ion, lauryldimethylethylammonium ion, didecyldimethylammonium ion, lauryldimethylbenzylammonium ion and tributylbenzylammonium ion. Examples of the tetraalkylphosphonium ion include tetramethylphosphonium ion, tetraethylphosphonium ion, tetrapropylphosphonium ion, tetrabutylphosphonium ion, and lauryltrimethylphosphonium ion. Further, examples of the tetrapropyl onium ion and the tetrabutyl onium ion include tetra n-propyl onium ion and tetra n-butyl onium ion, respectively.

<Manufacturing method of radiation-sensitive sheet>
The radiation-sensitive sheet of the present embodiment is prepared by preparing an aqueous dispersion (slurry) containing fine fibrous cellulose, a hydrophilic resin, a radiation-sensitive composition, and other components, and forming the sheet. can get.
The method of forming a sheet is not particularly limited, but it is subjected to a coating step of coating the slurry on a substrate and drying the sheet to peel off the sheet formed from the substrate, or a papermaking step of making the slurry. It is preferable to obtain. Further, a radiation-sensitive sheet may be continuously produced by using a coating device and a belt-shaped base material. Among these, it is more preferable to obtain it by a coating process.

The material of the base material in the coating process is not particularly limited, but a material having high wettability to the slurry is preferable from the viewpoint of suppressing shrinkage of the sheet during drying, but the sheet formed after drying can be easily formed. It is preferably peelable. Resin films and plates and metal films and plates are preferably exemplified, but are not particularly limited. Specifically, resin films and plates such as acrylic, polyethylene terephthalate, vinyl chloride, polystyrene, polypropylene, polycarbonate and polyvinylidene chloride, metal films and plates such as aluminum, zinc, copper and iron plates, and their surfaces. Examples include those that have been oxidized, stainless films and plates, brass films and plates, and the like.

In the coating process, if the viscosity of the slurry is low and it develops on the base material, a dammed frame is fixed on the base material in order to obtain a radiation-sensitive sheet with a predetermined thickness and basis weight. May be used. The frame for damming is not particularly limited, but it is preferable to select, for example, a frame in which the end portion of the sheet that adheres after drying can be easily peeled off. From this point of view, a resin plate or a metal plate molded is more preferable. In the present embodiment, for example, a resin plate such as an acrylic plate, a polyethylene terephthalate plate, a vinyl chloride plate, a polystyrene plate, a polypropylene plate, a polycarbonate plate, a polyvinylidene chloride plate, or a metal plate such as an aluminum plate, a zinc plate, a copper plate, or an iron plate. , And those whose surfaces are oxidized, stainless steel plates, brass plates and the like can be used.

The coating machine for coating the slurry on the base material is not particularly limited, but for example, a roll coater, a gravure coater, a die coater, a curtain coater, an air doctor coater, or the like can be used. A die coater, a curtain coater, and a spray coater are particularly preferable because the thickness of the sheet can be made more uniform.

The slurry temperature and the atmospheric temperature when the slurry is applied to the substrate are not particularly limited, but are preferably, for example, 5 ° C. or higher and 80 ° C. or lower, more preferably 10 ° C. or higher and 60 ° C. or lower, and 15 ° C. It is more preferably 50 ° C. or lower, and particularly preferably 20 ° C. or higher and 40 ° C. or lower. When the coating temperature is equal to or higher than the above lower limit, the slurry can be coated more easily. When the coating temperature is equal to or lower than the above upper limit, volatilization of the dispersion medium during coating and side reactions due to heat can be suppressed.

The method for drying the slurry coated on the substrate is not particularly limited, and examples thereof include a non-contact drying method, a method of drying while restraining the sheet, or a combination thereof.
The non-contact drying method is not particularly limited, and for example, a method of heating and drying with hot air, infrared rays, far infrared rays or near infrared rays (heat drying method), or a method of vacuum drying (vacuum drying method) is applied. can do. The heat drying method and the vacuum drying method may be combined, but the heat drying method is usually applied. Drying with infrared rays, far infrared rays, or near infrared rays is not particularly limited, and can be performed using, for example, an infrared device, a far infrared device, or a near infrared device.
The heating temperature in the heat drying method is not particularly limited, but is preferably 20 ° C. or higher, more preferably 50 ° C. or higher, and preferably 150 ° C. or lower, more preferably 120 ° C. or lower, still more preferably 100 ° C. or lower. be. When the heating temperature is set to be equal to or higher than the above lower limit value, the dispersion medium can be rapidly volatilized. Further, when the heating temperature is not more than the above upper limit value, it is possible to suppress the cost required for heating and suppress the discoloration and side reactions of the fibrous cellulose due to heat.

The papermaking process is performed by making the slurry with a paper machine. The paper machine used in the paper making process is not particularly limited, and examples thereof include continuous paper machines such as a long net type, a circular net type, and an inclined type, and a multi-layer paper making machine combining these. In the papermaking process, a known papermaking method such as hand-making may be adopted.
The papermaking process is performed by filtering and dehydrating the slurry with a wire to obtain a wet paper sheet, and then pressing and drying the sheet. The filter cloth used for filtering and dehydrating the slurry is not particularly limited, but for example, a fibrous cellulose, a hydrophilic resin, and a radiation-sensitive composition do not pass through, and the filtration rate does not become too slow. More preferably. Such a filter cloth is not particularly limited, but for example, a sheet made of an organic polymer, a woven fabric, or a porous membrane is preferable. The organic polymer is not particularly limited, but non-cellulosic organic polymers such as polyethylene terephthalate, polyethylene, polypropylene, and polytetrafluoroethylene (PTFE) are preferable. In the present embodiment, for example, a porous membrane of polytetrafluoroethylene having a pore size of 0.1 μm or more and 20 μm or less, polyethylene terephthalate having a pore size of 0.1 μm or more and 20 μm or less, a polyethylene woven fabric, or the like can be mentioned.

In the papermaking process, a method of producing a sheet from the slurry includes, for example, a water-squeezed section in which the slurry is discharged onto the upper surface of an endless belt and a dispersion medium is squeezed from the discharged slurry to generate a web, and a web. This can be done using a manufacturing apparatus that includes a drying section that is dried to produce a sheet. An endless belt is arranged from the watering section to the drying section, and the web generated in the watering section is conveyed to the drying section while being placed on the endless belt.

The dehydration method used in the papermaking process is not particularly limited, and examples thereof include a dehydration method normally used in the production of paper. Among these, a method of dehydrating with a long net, a circular net, an inclined wire or the like and then further dehydrating with a roll press is preferable. The drying method used in the papermaking process is not particularly limited, and examples thereof include a method used in the production of paper. Among these, a drying method using a cylinder dryer, a Yankee dryer, hot air drying, a near infrared heater, an infrared heater, or the like is more preferable.

<Characteristics of radiation-sensitive sheet>
The thickness of the radiation-sensitive sheet is preferably 10 μm or more, more preferably 20 μm or more, further preferably 25 μm or more, and preferably 1,000 μm or less, from the viewpoint of enabling shape stability and fine patterning. It is more preferably 500 μm or less, still more preferably 100 μm or less.
The amount of coating and the amount of papermaking may be appropriately adjusted so that the thickness of the radiation-sensitive sheet is within the above range.

The radiation-sensitive sheet of the present embodiment preferably has excellent light transmittance, and the total light transmittance is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, still more preferably 90. % Or more and 100% or less, preferably 99.5% or less from the viewpoint of ease of manufacture.
Total light transmittance is measured with a haze meter in accordance with JIS K 7361-1: 1997.

Further, the radiation-sensitive sheet of the present embodiment is preferably excellent in transparency, and the haze is preferably 10% or less, more preferably 3% or less, further preferably 2% or less, and 0% or more. Yes, from the viewpoint of ease of manufacture, it is preferably 0.1% or more.
Haze is measured with a haze meter in accordance with JIS K 7136: 2000.

<Patterned sheet>
The patterned radiation-sensitive sheet of the present embodiment is obtained by exposing the above-described radiation-sensitive sheet of the present embodiment and removing (developing) an unexposed portion or an exposed portion to form a pattern.
Irradiation usually selectively exposes at least a portion of the radiation sensitive sheet via a photomask or the like, for example using a contact aligner, stepper or scanner.
The light source for exposure is not particularly limited, but for example, known exposure techniques such as a high-pressure mercury lamp, a metal halide lamp, an ultra-high pressure mercury lamp, a KrF excimer laser, an ArF excimer laser, an EUV irradiation device, a soft X-ray irradiation device, and an electronic drawing device. Is exemplified. It may have a post-exposure baking (PEB) step.
Among the radiations to be applied to the radiation-sensitive sheet, radiation having a wavelength of 313 nm or more is preferable, and radiation containing ultraviolet rays of 365 nm is particularly preferable. Therefore, as an exposure light source, radiation having a wavelength of 313 nm or more including ultraviolet rays of 365 nm is irradiated. High-pressure mercury lamps, metal halide lamps, and ultra-high pressure mercury lamps that can be used are more preferable. By using these exposure light sources, a relatively high transmittance can be obtained even in a sheet having a thickness of 10 μm or more in a wavelength region of 313 nm or more, and the back surface of the radiation-sensitive sheet is sufficiently exposed without reducing the amount of light. be able to. ^{The exposure amount is preferably 3 mJ / cm 2} or more and 1,000 mJ / cm ² or less, as a value obtained by measuring the intensity of radiation at a wavelength of 365 nm with an illuminometer (OA1 model 356, manufactured by OA1 Optical Associates 1 nc.), More preferably. It is 10 mJ / cm ² or more and 500 mJ / cm ² or less.

As the developing method, for example, a shower developing method, a spray developing method, a dipping developing method, a paddle developing method, or the like may be adopted.
As the developing solution, an alkaline developing solution, water, or a water-miscible organic solvent can be used.
Examples of the alkaline developing solution include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, and methyldiethylamine. , Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4 .3.0] An alkaline aqueous solution in which at least one alkaline compound such as -5-nonene is dissolved is exemplified.
Of these, an aqueous TMAH solution is preferable. The concentration of the alkaline developer is preferably 0.1% by mass or more and 2.38% by mass or less, and more preferably 0.4% by mass or 2.38% by mass or less.
Water-miscible organic solvents include, for example, alcohols such as methanol, ethanol, 1-propanol, isopropyl alcohol (IPA), t-butanol, 1-methoxy-2-propanol (PGME); ethylene glycol, glycerin and the like. Polyhydric alcohols; Ketones such as acetone; Ethers such as tetrahydrofuran; Esters such as ethyl acetate and methyl acetate; Amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone; Examples thereof include sulfoxides such as dimethyl sulfoxide. Any one of these may be used, or two or more thereof may be used in combination.
Among these, alcohols such as ethanol, IPA and PGME are preferable.
The content of the organic solvent in the organic solvent developer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 99% by mass or more. Examples of the components other than the organic solvent in the organic solvent developer include water, silicone oil and the like.
Further, the formed pattern after development may be further rinsed (washed) with a rinsing solution.

The patterned sheet is particularly suitable for applications that require transparency, such as color filters for displays and conductive films for touch panels.

The features of the present invention will be described in more detail below with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

<Manufacturing example 1>
[Manufacturing of fine fibrous cellulose dispersion (1)]
As raw material pulp, softwood kraft pulp manufactured by Oji Paper Co., Ltd. (solid content 93% by mass, basis weight 245 g / m ² , sheet-like, disintegrated and measured according to JIS P 811-2: 2012 Canadian standard drainage Degree (CSF) of 700 ml) was used.
The raw material pulp was subjected to phosphorus oxo oxidation treatment as follows.
First, a mixed aqueous solution of ammonium dihydrogen phosphate and urea is added to 100 parts by mass (absolute dry mass) of the raw material pulp to obtain 45 parts by mass of ammonium dihydrogen phosphate, 120 parts by mass of urea, and 150 parts by mass of water. To obtain a chemical-impregnated pulp. Next, the obtained chemical-impregnated pulp was heated in a hot air dryer at 165 ° C. for 250 seconds to introduce a phosphorus oxo acid group into the cellulose in the pulp to obtain a phosphorus oxo oxide pulp 1.

Next, the obtained phosphorus oxo oxide pulp 1 was washed.
The washing treatment is carried out by repeating the operation of pouring 10 L of ion-exchanged water into 100 g (absolute dry mass) of phosphorus oxo oxide pulp, stirring the pulp dispersion liquid so that the pulp is uniformly dispersed, and then filtering and dehydrating the pulp. went. When the electrical conductivity of the filtrate became 100 μS / cm or less, the washing end point was set.

Next, the washed phosphorus oxo oxide pulp was neutralized as follows.
First, the washed phosphorus oxo oxide pulp was diluted with 10 L of ion-exchanged water, and then a 1N aqueous sodium hydroxide solution was added little by little with stirring to obtain a phosphorus oxo oxide pulp slurry having a pH of 12 or more and 13 or less. .. Then, the phosphorus oxo oxide pulp slurry was dehydrated to obtain a neutralized phosphorus oxo oxide pulp. Next, the above-mentioned washing treatment was performed on the phosphorus oxo-oxidized pulp after the neutralization treatment.

The infrared absorption spectrum of the obtained phosphorus oxo-oxidized pulp was measured using FT-IR. As a result, absorption ^{of the phosphate group based on P = O was observed around 1230 cm -1} , and it was confirmed that the phosphate group was added to the pulp.
Further, when the obtained phosphorous oxide pulp was tested and analyzed by an X-ray diffractometer, it was found at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less. A typical peak was confirmed, and it was confirmed that it had cellulose type I crystals.

Ion-exchanged water was added to the obtained phosphorus oxo oxide pulp 1 to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated twice with a wet atomizing device (manufactured by Sugino Machine Limited, Starburst) at a pressure of 200 MPa to obtain a fine fibrous cellulose dispersion liquid (1) containing fine fibrous cellulose.
By X-ray diffraction, it was confirmed that this fine fibrous cellulose maintained the cellulose type I crystal.
Moreover, when the fiber width of the fine fibrous cellulose was measured using a transmission electron microscope, it was 3 to 5 nm. The amount of phosphorus oxo acid groups (first dissociated acid amount) was 1.45 mmol / g. The total amount of dissociated acid was 2.45 mmol / g.

<Manufacturing example 2>
[Manufacturing of fine fibrous cellulose dispersion (2)]
The same procedure as in Production Example 1 was carried out except that 33 parts by mass of phosphorous acid (phosphonic acid) was used instead of ammonium dihydrogen phosphate to obtain phosphoroxo oxide pulp 2 and fine fibrous cellulose dispersion (2). rice field.

The infrared absorption spectrum of the obtained phosphorus oxo oxide pulp 2 was measured using FT-IR. As a result, ^{P = O-based absorption of the phosphonic acid group, which is a metamorphic form of the phosphite group, was observed near 1210 cm -1} , and a (sub) phosphorous acid group (phosphonic acid group) was added to the pulp. It was confirmed that there was.

Further, when the obtained phosphorus oxo oxide pulp 2 was tested and analyzed by an X-ray diffractometer, two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less, were located. A typical peak was confirmed in, and it was confirmed that it had cellulose type I crystals.

By X-ray diffraction, it was confirmed that the obtained fine fibrous cellulose maintained cellulose type I crystals. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. Regarding the fine fibrous cellulose dispersion (2), the amount of phosphorous acid group (first dissociated acid amount) introduced into cellulose and the total amount of dissociated acid were 1.51 mmol / g and 1.54 mmol / g, respectively. there were.

<Manufacturing example 3>
[Manufacturing of fine fibrous cellulose dispersion (3)]
As the raw material pulp, softwood kraft pulp (undried) manufactured by Oji Paper Co., Ltd. was used. Alkaline TEMPO oxidation treatment was carried out on this raw material pulp as follows.
First, the raw material pulp corresponding to 100 parts by mass of dry mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl), and 10 parts by mass of sodium bromide are added to 10 parts by mass of water. It was dispersed in 000 parts by mass. Then, 13 parts by mass of an aqueous sodium hypochlorite solution was added to 1.0 g of pulp so as to be 3.8 mmol, and the reaction was started. During the reaction, a 0.5 M aqueous sodium hydroxide solution was added dropwise to keep the pH at 10 or more and 10.5 or less, and the reaction was considered to be completed when no change was observed in the pH.

Next, the obtained TEMPO oxide pulp was washed.
In the washing treatment, the pulp slurry after TEMPO oxidation is dehydrated to obtain a dehydrated sheet, and then 5,000 parts by mass of ion-exchanged water is poured, stirred and uniformly dispersed, and then filtered and dehydrated is repeated. Was done by. When the electrical conductivity of the filtrate became 100 μS / cm or less, the washing end point was set.

Further, when the obtained TEMPO oxide pulp was tested and analyzed by an X-ray diffractometer, it was found at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less. A typical peak was confirmed, confirming that it had cellulose type I crystals.

Ion-exchanged water was added to the obtained TEMPO oxidized pulp to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated twice with a wet atomizing device (manufactured by Sugino Machine Limited, Starburst) at a pressure of 200 MPa to obtain a fine fibrous cellulose dispersion liquid (3) containing fine fibrous cellulose.

Regarding the fine fibrous cellulose dispersion liquid (3), the amount of carboxy groups introduced into the cellulose was 1.30 mmol / g.

<Measurement method of fiber width and ionic group amount of fine fibrous cellulose>
[Measurement of fiber width]
The fiber width of the fine fibrous cellulose was measured by the following method. The supernatant of the fine fibrous cellulose dispersion was diluted with water so that the concentration of the fine fibrous cellulose was 0.01% by mass or more and 0.1% by mass or less, and the solution was added dropwise to the hydrophilized carbon grid film. This was dried, stained with uranyl acetate, and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.).

[Measurement of phosphorus oxo acid group amount]
The amount of phosphorus oxo acid groups in the fine fibrous cellulose is a fine fibrous cellulose-containing slurry prepared by diluting a dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content is 0.2% by mass. On the other hand, the measurement was carried out by performing a treatment with an ion exchange resin and then performing a titration with an alkali.
In the treatment with the ion exchange resin, a strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, conditioned) having a volume of 1/10 is added to the fine fibrous cellulose-containing slurry, and the mixture is shaken for 1 hour. , The resin and the slurry were separated by pouring on a mesh having a mesh size of 90 μm.
In addition, titration using alkali changes the pH value indicated by the slurry while adding 10 μL of a 0.1 N sodium hydroxide aqueous solution to the fine fibrous cellulose-containing slurry treated with an ion exchange resin every 5 seconds. It was done by measuring. The titration was performed while blowing nitrogen gas into the slurry from 15 minutes before the start of the titration. In this neutralization titration, two points are observed where the increment (differential value of pH with respect to the amount of alkali dropped) becomes maximum in the curve plotting the measured pH with respect to the amount of alkali added. Of these, the maximum point of the increment obtained first when alkali is added is called the first end point, and the maximum point of the increment obtained next is called the second end point (FIG. 1). The amount of alkali required from the start of titration to the first end point is equal to the amount of first dissociated acid in the slurry used for titration. Further, the amount of alkali required from the start of titration to the second end point becomes equal to the total amount of dissociated acid in the slurry used for titration. The amount of alkali (mmol) required from the start of titration to the first end point divided by the solid content (g) in the slurry to be titrated was defined as the amount of phosphate groups (mmol / g).

[Measurement of carboxy group amount]
The amount of carboxy group of the fine fibrous cellulose is [phosphoroic acid group] except that 50 μL of 0.1 N sodium hydroxide aqueous solution is added to the fine fibrous cellulose-containing slurry after treatment with an ion exchange resin once every 30 seconds. Amount measurement] was performed in the same manner. The amount of carboxy group (mmol / g) is obtained by dividing the amount of alkali (mmol) required in the region corresponding to the first region shown in FIG. 2 of the measurement results by the solid content (g) in the slurry to be titrated. Calculated.

<Manufacturing example 4>
[Production of Radiation Sensitive Composition (1)]
A flask equipped with a cooling tube and a stirrer was charged with 14.6 parts by mass of triethylenetetramine (manufactured by Tokyo Chemical Industry Co., Ltd.), 51 parts by mass of triethylamine, and 200 parts by mass of dichloromethane. Under an ice bath, 45 parts by mass of acryloyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to this solution over 1 hour, and after completion of the addition, the mixture was stirred at room temperature for 1 hour. After washing by adding 1N hydrochloric acid water to the reaction solution, it was washed with an aqueous sodium hydrogen carbonate solution, then with a 10% aqueous sodium chloride solution, and then magnesium sulfate was added to the organic layer. The solvent was distilled off under reduced pressure from the organic layer from which magnesium sulfate was filtered and removed, and then dried under reduced pressure to obtain 36 g of a polymerizable acrylamide compound.
A mixture of 1.0 part by mass of the obtained compound and 0.1 part by mass of 2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) is 0.5. IPA was added so as to be a mass%, and the mixture was dissolved. Then, the radiation-sensitive composition (1) was prepared by filtering with a millipore filter having a pore size of 0.5 μm.

<Manufacturing example 5>
[Production of Radiation Sensitive Composition (2)]
Dipentaerythritol hexaacrylate (DPHA) (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-DPH) 1.0 part by mass and 2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone (2-hydroxyethoxy) -2-methylpropiophenone ( 1-Methyl-2-propanol was added and dissolved so that the mixture with 0.1 parts by mass (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was 0.5% by mass. Then, the radiation-sensitive composition (2) was prepared by filtering with a millipore filter having a pore size of 0.5 μm.

<Example 1>
(Dissolution of polyvinyl alcohol)
Polyvinyl alcohol (PVA) (manufactured by Kuraray Co., Ltd., Poval 105, degree of polymerization: 500, degree of saponification: 98-99 mol%) was added to ion-exchanged water so as to be 0.5% by mass, and the temperature was 95 ° C. for 1 hour. The mixture was stirred and dissolved to obtain an aqueous polyvinyl alcohol solution.

(Manufacturing of radiation-sensitive sheets)
Ion-exchanged water was added to the fine fibrous cellulose dispersion (1) having a solid content concentration of 2.0% by mass to obtain a fine fibrous cellulose dispersion (A) having a solid content of 0.5% by mass.
To 50 parts by mass of the obtained fine fibrous cellulose dispersion (A), 20 parts by mass of an aqueous polyvinyl alcohol solution and 30 parts by mass of a solution of a radiation-sensitive composition (1) were added and stirred. Further, the mixed liquid was weighed so that the finished basis weight of the sheet was 50 g / m ² , developed on a commercially available acrylic plate, and dried in a dryer at 50 ° C. for 24 hours. A 150 mm square dammed plate was placed on the acrylic plate so as to have a predetermined basis weight. A radiation-sensitive sheet was obtained by the above procedure.
The thickness of the obtained radiation-sensitive sheet was 38 μm.

<Example 2>
Radiation-sensitive in the same manner as in Example 1 except that the polyvinyl alcohol aqueous solution was 17 parts by mass and the radiation-sensitive composition (1) solution was 40 parts by mass with respect to 43 parts by mass of the fine fibrous cellulose dispersion (A). Obtained a sex sheet.

<Example 3>
Radiation-sensitive in the same manner as in Example 1 except that the polyvinyl alcohol aqueous solution was 14 parts by mass and the radiation-sensitive composition (1) solution was 50 parts by mass with respect to 36 parts by mass of the fine fibrous cellulose dispersion (A). Obtained a sex sheet.

<Example 4>
Ion-exchanged water was added to the fine fibrous cellulose dispersion (2) having a solid content concentration of 2.0% by mass to obtain a fine fibrous cellulose dispersion (B) having a solid content of 0.5% by mass.
A radiation-sensitive sheet was obtained in the same manner as in Example 1 except that the fine fibrous cellulose dispersion (B) was used instead of the fine fibrous cellulose dispersion (A).

<Example 5>
Ion-exchanged water was added to the fine fibrous cellulose dispersion (3) having a solid content concentration of 2.0% by mass to obtain a fine fibrous cellulose dispersion (C) having a solid content of 0.5% by mass.
A radiation-sensitive sheet was obtained in the same manner as in Example 1 except that the fine fibrous cellulose dispersion (C) was used instead of the fine fibrous cellulose dispersion (A).

<Example 6>
A radiation-sensitive sheet was obtained in the same manner as in Example 1 except that the radiation-sensitive composition (2) was used instead of the radiation-sensitive composition (1).

<Comparative example 1>
(Porous sheet)
A wet sheet was prepared by reducing the pressure of the fine fibrous cellulose dispersion (A) on a 500 mesh polyester mesh. The solid content of this wet sheet was 10%. On the obtained wet sheet, 100 parts of diethylene glycol dimethyl ether (manufactured by Toho Chemical Industry Co., Ltd., trade name: "High Solve MDM") was uniformly applied to 100 parts of the wet sheet by spraying. Further, the pressure was reduced to form a wet sheet containing water and an organic solvent. The solid content of this wet sheet was 10%. This wet sheet was dried with a cylinder roll together with a 500 mesh polyester mesh at 80 ° C. for 3 minutes so that the wet sheet was in contact with the mirror surface to obtain a sheet after the first drying. The obtained sheet after the first drying was in a damp state. The sheet after the first drying was dried in a dryer at 130 ° C. for 3 minutes (second drying step). The obtained sheet after the second drying was in a dried state. This sheet was peeled off from the polyester mesh to obtain a fine fibrous cellulose-containing sheet.

(Immersion of radiation sensitive resin)
The fine fibrous cellulose-containing sheet was immersed in the solution of the radiation-sensitive composition (1) and allowed to stand for 3 minutes. Then, this sheet was taken out, and the sheet was dried under reduced pressure with a decompression device (MUE-2000) manufactured by ULVAC, and the solvent in the sheet was removed under reduced pressure. The basis weight of the obtained sheet was 50 g / m ² . The thickness of the obtained radiation-sensitive sheet was 70 μm.

<Comparative example 2>
A chromatographic filter paper (manufactured by Toyo Filter Paper Co., Ltd., No. 51B, 87 g / m ² ) was immersed in the solution of the radiation-sensitive resin composition (1) and allowed to stand for 3 minutes. Then, this sheet was taken out, the sheet was dried under reduced pressure with a decompression device (MUE-2000) manufactured by ULVAC, and the solvent in the sheet was removed under reduced pressure. The basis weight of the obtained sheet was 124 g / m ² . The thickness of the obtained radiation-sensitive sheet was 170 μm.

[Measuring method]
<Total light transmittance of sheet>
The total light transmittance was measured using a haze meter (HM-150, manufactured by Murakami Color Technology Laboratory Co., Ltd.) in accordance with JIS K 7361-1: 1997. The results are shown in Table 1.

<Sheet haze>
The haze was measured using a haze meter (HM-150, manufactured by Murakami Color Technology Laboratory Co., Ltd.) in accordance with JIS K 7136: 2000. The results are shown in Table 1.

<Patterning on sheet>
A radiation-sensitive sheet or a resin-impregnated sheet was installed in an exposure apparatus equipped with a metal halide lamp (manufactured by Eye Graphics Co., Ltd., model number Eye Grandage ECS-4011GX / N, wavelength 200 to 450 nm). Next, a photomask (manufactured by Toppan Printing Co., Ltd., made of synthetic quartz, L / S = 400/400, 1100/1100 μm) was placed on the sheet. At this time, a shim tape (manufactured by Misumi Group Inc., thickness 500 μm, manufactured by SUS) was used so that the gap between the pattern-forming base material and the photomask was 500 μm.
^{Next, the intensity of the radiation at a wavelength of 365 nm was set to 500 mJ / cm 2} using an illuminometer (OA1 model 356, manufactured by OA1 Optical Associates 1 nc.), And then exposed using an exposure apparatus.

Next, the exposed sheet was dipped into IPA for 3 minutes and developed.
As described above, a patterned sheet in which the resin for the radiation-sensitive composition was removed only in the unexposed portion of the sheet was obtained.

Next, this sheet was impregnated with the IPA solution of Solvent Red 49 for 3 minutes, and then dipped into the IPA for 3 minutes for washing.
From the above, a sheet impregnated with Solvent Red 49 only in the portion from which the resin for the radiation-sensitive composition was removed was obtained.

When this sheet was observed with an optical microscope, both L / S = 400/400 μm and 1100/1100 μm were evaluated as “A” if a pattern was formed, and a pattern of L / S = 400/400 μm was not formed. However, if the pattern of L / S = 1100/1100 μm was formed, it was evaluated as “B”, and if the pattern was not formed in both L / S = 400/400 μm and 1100/1100 μm, it was evaluated as “C”. The results are shown in Table 1.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a radiation-sensitive sheet having excellent transparency and capable of fine patterning, and the patterned sheet obtained by exposing and developing the radiation-sensitive sheet can be used as a color filter or a touch panel of a display. It is expected to be used in applications that require transparency, such as conductive films for use.

Claims

Contains a radiation-sensitive composition, fine fibrous cellulose with a fiber width of 1,000 nm or less, and a hydrophilic polymer.
The content of the hydrophilic polymer with respect to 100 parts by mass of the fine fibrous cellulose is 10 parts by mass or more.
Radiation sensitive sheet.
The radiation-sensitive composition according to claim 1, wherein the radiation-sensitive composition comprises a radiation-sensitive compound and a resin for a radiation-sensitive composition whose solubility in a solvent is increased or decreased by the irradiated radiation-sensitive compound. Sex sheet.
The radiation-sensitive sheet according to claim 2, wherein the radiation-sensitive compound contains at least one of a photoacid generator and a photopolymerization initiator.
The radiation-sensitive sheet according to any one of claims 1 to 3, wherein the content of the radiation-sensitive composition in the solid content of the radiation-sensitive sheet is 10% by mass or more.
The radiation-sensitive sheet according to any one of claims 1 to 4, wherein the total light transmittance of the radiation-sensitive sheet is 70% or more.
The radiation-sensitive sheet according to any one of claims 1 to 5, wherein the haze of the radiation-sensitive sheet is 10% or less.
The radiation-sensitive sheet according to any one of claims 1 to 6, wherein the fine fibrous cellulose has an anionic group.
The radiation-sensitive sheet according to any one of claims 1 to 7, wherein the fine fibrous cellulose has a phosphoric acid group or a group derived from a phosphoric acid group.
The radiation-sensitive sheet according to any one of claims 1 to 8, wherein the radiation-sensitive composition is dissolved in at least one of water, alcohol, and a mixed solvent thereof.
The radiation-sensitive sheet according to any one of claims 1 to 9, wherein the hydrophilic polymer is selected from polyethylene glycol, polyethylene oxide, polyvinyl alcohol, and modified polyvinyl alcohol.
The radiation-sensitive sheet according to any one of claims 1 to 10, wherein the radiation-sensitive sheet is a negative type radiation-sensitive sheet.
A patterned sheet in which at least a part of an exposed portion or an unexposed portion of the radiation-sensitive sheet according to any one of claims 1 to 11 is removed.
A radiation-sensitive composition used for the radiation-sensitive sheet according to any one of claims 1 to 11.