JP7187895B2 - FIBROUS CELLULOSE-CONTAINING RESIN COMPOSITION, LIQUID COMPOSITION, MOLDED PRODUCT AND METHOD FOR MANUFACTURING MOLDED PRODUCT - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fibrous cellulose-containing resin composition, a liquid composition, a molded article, and a method for producing a molded article.

A polyimide resin is a thermosetting resin obtained by curing a polyimide precursor such as polyamic acid. Polyimide resins have high heat resistance and excellent mechanical and electrical properties. Therefore, sheets formed from polyimide resins are used as substrates for circuit wiring boards and the like. When a sheet is produced from a polyimide resin, a polyamic acid solution is cast on a base material, followed by cast drying. However, a sheet made of polyimide resin has a problem that it has strong adhesion to a substrate and is difficult to separate from the substrate.

In order to solve such problems, it has been studied to increase the releasability from the substrate by setting the glass transition temperature of the substrate and the polyimide film within a predetermined range (Patent Document 1). However, in such a case, it is necessary to set the imidization treatment temperature to a high temperature of 300° C. or higher, which limits the fields of application. A method of casting with a solvent interposed between the base material and the polyamic acid solution has also been studied (Patent Document 2).

By the way, as fibrous cellulose, fine fibrous cellulose having a fiber diameter of 1 μm or less is known. Such fine fibrous cellulose is attracting attention as a new material, and its uses are diverse. For example, development of resin composites containing fine fibrous cellulose is underway. By blending the fine fibrous cellulose with the resin, the number of contact points between the fibers increases, so that the strength and rigidity can be improved.

For example, Patent Document 3 discloses a transparent composite film characterized by cross-linking a polyimide resin and cellulose nanofibers. Here, cellulose nanofibers are obtained by oxidation treatment of pulp with 2,2,6,6-tetramethylpiperidine-N-oxyl. Further, Patent Document 4 discloses a printed wiring board material comprising a binder component, cellulose nanofibers having a number average fiber diameter of 3 nm to 1000 nm, and an acrylic copolymer compound. Here, the use of thermosetting polyimide as the binder component is being studied. In Patent Document 4, unmodified cellulose nanofibers are used as the cellulose nanofibers.

JP 2011-056824 A JP 2009-167235 A JP 2013-018931 A JP 2014-220343 A

Polyimide resin moldings containing fine fibrous cellulose as described above tend to have a reduced coefficient of linear thermal expansion and coefficient of thermal shrinkage. However, even such a polyimide resin molded article is often not sufficiently peelable from the substrate, and there is a demand for the development of a polyimide resin molded article having even more excellent substrate peelability.

In order to solve the problems of the prior art, the inventors of the present invention conducted studies with the aim of providing a polyimide resin molded article having excellent substrate peelability.

As a result of intensive studies to solve the above problems, the present inventors have found a fine fibrous cellulose having an anionic group and an organic onium ion having a predetermined structure as a counterion for the anionic group. The inventors have found that by blending polyimide resin with polyimide resin, it is possible to obtain a molded product having excellent peelability from a substrate.
Specifically, the present invention has the following configurations.

[1] A fibrous cellulose having a fiber width of 1000 nm or less and having an anionic group, at least one selected from polyimide resins and polyimide precursors, and an organic onium ion as a counterion for the anionic group,
The organic onium ion is a fibrous cellulose-containing resin composition that satisfies at least one condition selected from the following (a) and (b);
(a) contains a hydrocarbon group having 5 or more carbon atoms;
(b) The total number of carbon atoms is 17 or more.
[2] The fibrous cellulose-containing resin composition according to [1], wherein the organic onium ion is an organic ammonium ion.
[3] The fibrous cellulose-containing resin composition according to [1] or [2], wherein the fibrous cellulose has an anionic group content of 0.50 mmol/g or more.
[4] A liquid composition obtained by mixing the fibrous cellulose-containing resin composition according to any one of [1] to [3] with an organic solvent.
[5] A molded article formed from the fibrous cellulose-containing resin composition according to any one of [1] to [3] or the liquid composition according to [4].
[6] The formed article according to [5], which is in the form of a sheet.
[7] Forming a molded body from the fibrous cellulose-containing resin composition according to any one of [1] to [3] or the liquid composition according to [4] using a substrate or a mold. and
and a step of releasing the molded article from the substrate or releasing the molded article from the mold.
[8] A step of applying the fibrous cellulose-containing resin composition according to any one of [1] to [3] or the liquid composition according to [4] onto a substrate to form a coating film; ,
a step of heating the coating film to form a sheet;
and peeling the sheet from the substrate.

ADVANTAGE OF THE INVENTION According to this invention, the polyimide resin molding excellent in base-substrate peelability can be provided.

FIG. 1 is a graph showing the relationship between the amount of NaOH added to fibrous cellulose having a phosphate group and electrical conductivity. FIG. 2 is a graph showing the relationship between the amount of NaOH added to fibrous cellulose having a carboxyl group and the electrical conductivity.

The present invention will be described in detail below. Although the constituent elements described below may be described based on representative embodiments and specific examples, the present invention is not limited to such embodiments.

(Fibrous cellulose-containing resin composition)
The present invention includes fibrous cellulose having a fiber width of 1000 nm or less and having an anionic group, at least one selected from polyimide resins and polyimide precursors, and an organic onium ion as a counterion for the anionic group. It relates to a fibrous cellulose-containing resin composition. Here, the organic onium ion satisfies at least one condition selected from the following (a) and (b).
(a) contains a hydrocarbon group having 5 or more carbon atoms;
(b) The total number of carbon atoms is 17 or more.
In this specification, fibrous cellulose having a fiber width of 1000 nm or less is sometimes referred to as fine fibrous cellulose.

Since the fibrous cellulose-containing resin composition of the present invention has the above structure, a molded article such as a sheet formed from the fibrous cellulose-containing resin composition has excellent substrate peelability. For example, typical base materials used for producing a molded body containing polyimide resin include a glass base material and a SUS base material, and a molded body such as a sheet is formed on these base materials. Excellent substrate releasability is exhibited when this is done.

In addition, in the fibrous cellulose-containing resin composition of the present invention, the fine fibrous cellulose has good dispersibility in at least one selected from polyimide resins and polyimide precursors. Therefore, a molded article such as a sheet formed from the fibrous cellulose-containing resin composition can maintain the high transparency of the polyimide resin. Also, the molded article in which the fine fibrous cellulose is uniformly dispersed exhibits high strength.

The fine fibrous cellulose used in the present invention also has good dispersibility in organic solvents. Therefore, even when the fibrous cellulose-containing resin composition is further blended with an organic solvent, good dispersibility can be maintained and sediments are not formed in the liquid composition. Moreover, a liquid composition obtained by blending an organic solvent with a fibrous cellulose-containing resin composition has a high viscosity and is highly transparent. Accordingly, a molded article such as a sheet formed from such a liquid composition maintains the high transparency of the polyimide resin and has high strength.

The form of the fibrous cellulose-containing resin composition of the present invention is not particularly limited, and examples thereof include liquid, gel, and solid forms. The fibrous cellulose-containing resin composition of the present invention may be one in which fine fibrous cellulose is dispersed in at least one molten resin selected from polyimide resins and polyimide precursors. A hardened resin may also be used. The present invention may also be a liquid composition obtained by mixing a fibrous cellulose-containing resin composition and an organic solvent.

When the fibrous cellulose-containing resin composition of the present invention is in a solid form, its form is not particularly limited. Here, the powdery substance is a powdery and/or granular substance. In addition, a powdery substance means a substance smaller than a granular substance. In general, powdery substances refer to fine particles having a particle size of 1 nm or more and less than 0.1 mm, and granular substances refer to particles having a particle size of 0.1 mm to 10 mm, but are not particularly limited. In addition, in this specification, a granular material may be called powder. The particle size of the granules used herein can be measured and calculated using a laser diffraction method. Specifically, it is a value measured using a laser diffraction/scattering particle size distribution analyzer (Microtrac 3300EXII, Nikkiso Co., Ltd.).

The total content of the polyimide resin and the polyimide precursor in the fibrous cellulose-containing resin composition of the present invention is preferably 30% by mass or more, preferably 40% by mass, relative to the total mass of the fibrous cellulose-containing resin composition. % or more, more preferably 50 mass % or more, and particularly preferably 60 mass % or more. In addition, the total content of the polyimide resin and the polyimide precursor is preferably 99.9% by mass or less, more preferably 99% by mass or less, relative to the total mass of the fibrous cellulose-containing resin composition. , 97% by mass or less. In the fibrous cellulose-containing resin composition, the total content of the polyimide resin and the polyimide precursor is preferably higher than the content of the fine fibrous cellulose, and the polyimide resin is preferably the main component.

The content of fine fibrous cellulose in the fibrous cellulose-containing resin composition of the present invention is preferably 0.1% by mass or more, preferably 1% by mass, relative to the total mass of the fibrous cellulose-containing resin composition. It is more preferably 3% by mass or more, and more preferably 3% by mass or more. In addition, the content of fine fibrous cellulose is preferably 70% by mass or less, more preferably 60% by mass or less, and 50% by mass or less with respect to the total mass of the fibrous cellulose-containing resin composition. more preferably, and particularly preferably 40% by mass or less. By setting the content of the fine fibrous cellulose within the above range, it is possible to effectively improve the peelability of the substrate while maintaining the heat resistance and strength of the polyimide resin molding.

In the fibrous cellulose-containing resin composition of the present invention, the water content is preferably as low as possible. The water content in the fibrous cellulose-containing resin composition is preferably 5% by mass or less, more preferably 1% by mass or less, relative to the total mass of the fibrous cellulose-containing resin composition. Moreover, it is also preferable that the water content in the fibrous cellulose-containing resin composition is 0% by mass. The water content in the fibrous cellulose-containing resin composition was determined by placing 200 mg of the fibrous cellulose-containing resin composition on a moisture meter (manufactured by A&D, MS-70) and heating at 140°C. can be measured. The water content in the fibrous cellulose-containing resin composition can be calculated from the measured water content.

In the fibrous cellulose-containing resin composition of the present invention, the fine fibrous cellulose does not form a crosslinked structure with the polyimide resin or polyimide precursor. The crosslinked structure is a crosslinked structure derived from an ester group or an amide group. The presence or absence of such a crosslinked structure can be determined, for example, by measuring the infrared absorption spectrum using a Fourier transform infrared spectrophotometer (FT-IR) and confirming the presence or absence of a peak at a predetermined wavenumber.

(fine fibrous cellulose)
The fibrous cellulose-containing resin composition of the present invention has a fiber width of 1000 nm or less and contains fibrous cellulose having an anionic group. The fiber width of fibrous cellulose having an anionic group is preferably 100 nm or less, more preferably 8 nm or less. The fiber width of fibrous cellulose can be measured, for example, by electron microscope observation.

The average fiber width of fibrous cellulose is, for example, 1000 nm or less. The average fiber width of the fibrous cellulose is, for example, preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, even more preferably 2 nm or more and 50 nm or less, and 2 nm or more and 10 nm or less. Especially preferred. By setting the average fiber width of the fibrous cellulose to 2 nm or more, the dissolution of cellulose molecules in water is suppressed, and the effect of improving the strength, rigidity, and dimensional stability of the fibrous cellulose can be more readily exhibited. can. The fibrous cellulose is, for example, single fibrous cellulose.

The average fiber width of fibrous cellulose is measured, for example, using an electron microscope as follows. First, an aqueous suspension of fibrous cellulose with 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 form a sample for TEM observation. and SEM images of surfaces cast on glass may be observed if they contain wide fibers. Then, an electron microscope image is observed at a magnification of 1,000, 5,000, 10,000, or 50,000 times depending on the width of the fiber to be observed. However, the sample, observation conditions and magnification are adjusted so as to satisfy the following conditions.
(1) A single straight line X is drawn at an arbitrary point in the observed image, and 20 or more fibers intersect the straight line X.
(2) Draw a straight line Y that intersects the straight line perpendicularly in the same image, and 20 or more fibers intersect the straight line Y.
Widths of fibers intersecting the straight lines X and Y are visually read from the observation image satisfying the above conditions. In this way, at least three sets of observed images of surface portions that do not overlap each other are obtained. Then, for each image, the width of the fiber that crosses straight line X and straight line Y is read. This gives at least 20 x 2 x 3 = 120 fiber width readings. Then, the average value of the read fiber widths is taken as the average fiber width of the fibrous cellulose.

Although the fiber length of the fibrous cellulose is not particularly limited, it is preferably 0.1 μm or more and 1000 μm or less, more preferably 0.1 μm or more and 800 μm or less, and further preferably 0.1 μm or more and 600 μm or less. preferable. By setting the fiber length within the above range, destruction of the crystalline regions of the fibrous cellulose can be suppressed. Moreover, it becomes possible to make the slurry viscosity of fibrous cellulose into an appropriate range. The fiber length of fibrous cellulose can be determined by image analysis using, for example, TEM, SEM, and AFM.

Preferably, the fibrous cellulose has a Type I crystal structure. Here, the fact that the fibrous cellulose has a type I crystal structure can be identified in a diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ=1.5418 Å) monochromated with graphite. Specifically, it can be identified by having typical peaks at two positions near 2θ=14° or more and 17° or less and 2θ=22° or more and 23° or less. The proportion of the I-type crystal structure in the fine fibrous cellulose is, for example, preferably 30% or more, more preferably 40% or more, even more 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 degree of crystallinity is determined by a conventional method from the pattern of X-ray diffraction profiles (Seagal et al., Textile Research Journal, vol. 29, p. 786, 1959).

Although the axial ratio (fiber length/fiber width) of fibrous cellulose is not particularly limited, it is preferably 20 or more and 10,000 or less, and more preferably 50 or more and 1,000 or less. A sheet containing fine fibrous cellulose can be easily formed by making the axial ratio equal to or higher than the above lower limit. By setting the axial ratio to the above upper limit or less, handling such as dilution becomes easier, for example, when fibrous cellulose is treated as an aqueous dispersion, which is preferable.

The fibrous cellulose in this embodiment has, for example, both a crystalline region and an amorphous region. In particular, fine fibrous cellulose having both a crystalline region and an amorphous region and having a high axial ratio is realized by the method for producing fine fibrous cellulose described later.

Fibrous cellulose has anionic groups. The anionic group includes, for example, a phosphate group or a substituent derived from a phosphate group (sometimes simply referred to as a phosphate group), a carboxy group or a substituent derived from a carboxy group (sometimes simply referred to as a carboxy group), and a sulfone group or a substituent derived from a sulfone group (sometimes referred to simply as a sulfone group), and at least one selected from a phosphate group and a carboxy group. More preferably, it is particularly preferably a phosphate group. Since the phosphate group has more anionic groups per molecule than the carboxyl group and the like, it can have more organic onium ions as counter ions. It is considered that the dispersibility and the like of the fine fibrous cellulose can be further enhanced by this.

A phosphoric acid group or a substituent derived from a phosphoric acid group is, for example, a substituent represented by the following formula (1), and is generalized as a phosphoric acid group or a substituent derived from a phosphoric acid group.
A phosphate group is, for example, a divalent functional group corresponding to phosphoric acid from which a hydroxy group has been removed. Specifically, it is a group represented by —PO ₃ H ₂ . Substituents derived from a phosphate group include substituents such as salts of phosphate groups and phosphate ester groups. A substituent derived from a phosphoric acid group may be contained in the fibrous cellulose as a condensed group (for example, a pyrophosphate group) of the phosphoric acid group. Further, the phosphate group may be, for example, a phosphite group (phosphonic acid group), and the substituent derived from the phosphate group may be a phosphite group salt, a phosphite ester group, or the like. good too.

In formula (1), a, b and n are natural numbers (where a=b×m). a of α ^{1 , α 2} , . Note that all of αn and α′ may be O 2 ⁻ . Each R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated linear hydrocarbon group, an unsaturated-branched hydrocarbon group A hydrogen group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or a derivative group thereof. At least part of β ^b+ is an organic onium ion, which will be described later.

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

In addition, as the derivative group in R, at least one functional group such as a carboxy group, a hydroxy group, or an amino group is added or substituted with respect to the main chain or side chain of the above various hydrocarbon groups. Examples include, but are not limited to, groups. Although the number of carbon atoms constituting the main chain of R is not particularly limited, it is preferably 20 or less, more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R within the above range, the molecular weight of the phosphate group can be set within an appropriate range, facilitating penetration into the fiber raw material and increasing the yield of fine cellulose fibers. can also

β ^b+ is a monovalent or higher cation composed of an organic substance or an inorganic substance. The monovalent or higher cations composed of organic substances include aliphatic ammonium and aromatic ammonium, and at least part of β ^{b +} is an organic onium ion described later. Examples of monovalent or higher cations composed of inorganic substances include ions of alkali metals such as sodium, potassium, or lithium, cations of divalent metals such as calcium or magnesium, or hydrogen ions. It is not particularly limited. These may be applied singly or in combination of two or more. As the monovalent or higher cation made of an organic substance or an inorganic substance, sodium or potassium ions are preferable, but not particularly limited, because they are less likely to turn yellow when fiber raw materials containing β are heated, and are easily available industrially.

The amount of anionic groups introduced into fibrous cellulose (the amount of anionic groups) is, for example, preferably 0.10 mmol/g or more per 1 g (mass) of fibrous cellulose, more preferably 0.20 mmol/g or more. It is preferably 0.50 mmol/g or more, more preferably 1.00 mmol/g or more. In addition, the amount of anionic groups introduced into fibrous cellulose is, for example, preferably 5.20 mmol/g or less, more preferably 3.65 mmol/g or less per 1 g (mass) of fibrous cellulose. It is more preferably 00 mmol/g or less. Here, the unit mmol/g indicates the amount of substituents per 1 g mass of fibrous cellulose when the counter ion of the anionic group is hydrogen ion (H ⁺ ). By setting the amount of the anionic group to be introduced within the above range, the fiber raw material can be easily made finer, and the stability of the fibrous cellulose can be enhanced. Furthermore, by setting the amount of the anionic group to be introduced within the above range, the content of the organic onium ion that can be contained in the fibrous cellulose can be set within an appropriate range. As a result, the dispersibility of the fibrous cellulose in polyimide resins and organic solvents can be effectively enhanced.

The amount of anionic groups introduced into fibrous cellulose can be measured, for example, by conductivity titration. In the measurement by the conductivity titration method, the introduced amount is measured by determining the change in conductivity while adding an alkali such as an aqueous sodium hydroxide solution to the obtained slurry containing the fibrous cellulose.

FIG. 1 is a graph showing the relationship between the amount of NaOH added to fibrous cellulose having a phosphate group and electrical conductivity. The amount of phosphate groups introduced into fibrous cellulose is measured, for example, as follows. First, a slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. In addition, before the treatment with the strongly acidic ion exchange resin, a defibration treatment similar to the fibrillation treatment step described below may be performed on the object to be measured, if necessary. Next, change in electrical conductivity is observed while adding an aqueous sodium hydroxide solution to obtain a titration curve as shown in FIG. As shown in FIG. 1, the electrical conductivity drops sharply at first (hereinafter referred to as "first region"). After that, the conductivity starts to rise slightly (hereinafter referred to as "second region"). After that, the increment of conductivity increases (hereinafter referred to as "third region"). The boundary point between the second region and the third region is defined as the point where the second derivative of the conductivity, that is, the amount of change in the increment (slope) of the conductivity is maximized. Thus, three regions appear in the titration curve. Of these, the amount of alkali required in the first region is equal to the amount of strong acid groups in the slurry used for titration, and the amount of alkali required in the second region is the amount of weak acid groups in the slurry used for titration. be equal. When the phosphate groups condense, the weakly acidic groups are apparently lost, and the amount of alkali required for the second region becomes smaller than the amount of alkali required for the first region. On the other hand, the amount of strongly acidic groups coincides with the amount of phosphorus atoms regardless of the presence or absence of condensation. Therefore, the amount of phosphate groups introduced (or the amount of phosphate groups) or the amount of substituents introduced (or the amount of substituents) means the amount of strongly acidic groups. Therefore, the value obtained by dividing the alkali amount (mmol) required in the first region of the titration curve obtained above by the solid content (g) in the slurry to be titrated is the amount of phosphate group introduced (mmol/ g).

FIG. 2 is a graph showing the relationship between the amount of NaOH added to fibrous cellulose having a carboxyl group and the electrical conductivity. The amount of carboxyl groups introduced into fibrous cellulose is measured, for example, as follows. First, a slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. In addition, before the treatment with the strongly acidic ion exchange resin, a defibration treatment similar to the fibrillation treatment step described below may be performed on the object to be measured, if necessary. Next, change in electrical conductivity is observed while adding an aqueous sodium hydroxide solution to obtain a titration curve as shown in FIG. As shown in FIG. 2, the titration curve has a first region where the increment (slope) of the conductivity becomes almost constant after the electrical conductivity decreases, and then the increment (slope) of the conductivity increases. It is divided into a second area. The boundary point between the first region and the second region is defined as the point where the second differential value of the conductivity, that is, the amount of change in the increment (slope) of the conductivity becomes maximum. Then, the value obtained by dividing the alkali amount (mmol) required in the first region of the titration curve by the solid content (g) in the fine fibrous cellulose-containing slurry to be titrated is the introduction amount of the carboxy group ( mmol/g).

The amount of carboxyl groups introduced (mmol/g) mentioned above is the amount of substituents per 1 g of mass of fibrous cellulose (hereinafter referred to as the amount of carboxyl groups ( ^acid type)). On the other hand, when the counterion of the carboxy group is substituted 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 the counterion. , the amount of carboxy groups (hereinafter referred to as the amount of carboxy groups (C type)) possessed by fibrous cellulose whose counter ion is cation C can be obtained.
That is, the amount of carboxyl group introduced is calculated by the following formula.
Carboxy group introduction amount (C type) = carboxy group amount (acid form) / [1 + (W-1) × (carboxy group amount (acid form)) / 1000]
W: Formula weight per valence of cation C (for example, 23 for Na and 9 for Al)

In addition, in the measurement of the amount of substituents by the titration method, if the titration interval of the aqueous sodium hydroxide solution is too short, the amount of substituents may be lower than originally. It is desirable to titrate the sodium aqueous solution by 50 μL every 30 seconds.

<Manufacturing process of fine fibrous cellulose>
<Textile raw material>
Microfibrous cellulose is produced from fibrous raw materials containing cellulose. The fibrous raw material containing cellulose is not particularly limited, but pulp is preferably used because it is readily available and inexpensive. Pulp includes, for example, wood pulp, non-wood pulp, and deinked pulp. Examples of wood pulp include, but are not limited to, hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP). ) and chemical pulp such as oxygen bleached kraft pulp (OKP), semi-chemical pulp such as semi-chemical pulp (SCP) and chemigroundwood pulp (CGP), groundwood pulp (GP) and thermomechanical pulp (TMP, BCTMP) A mechanical pulp etc. are mentioned. Non-wood pulps include, but are not limited to, cotton-based pulps such as cotton linters and cotton lints, and non-wood-based pulps such as hemp, straw, and bagasse. Examples of deinked pulp include, but are not limited to, deinked pulp made from waste paper. The pulp of this embodiment may be used alone or in combination of two or more.
Among the above pulps, wood pulp and deinked pulp are preferred, for example, from the viewpoint of availability. In addition, among wood pulps, the cellulose ratio is high and the yield of fine fibrous cellulose at the time of defibration is high, and the decomposition of cellulose in the pulp is small, and fine fibrous cellulose of long fibers with a large axial ratio can be obtained. From the point of view, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are more preferable. The use of fine fibrous cellulose of long fibers with a large axial ratio tends to increase the viscosity.

As the fiber raw material containing cellulose, for example, cellulose contained in sea squirts and bacterial cellulose produced by acetic acid bacteria can be used. Fibers formed by straight-chain nitrogen-containing polysaccharide polymers such as chitin and chitosan can also be used instead of fiber raw materials containing cellulose.

<Phosphate group introduction step>
When the fine fibrous cellulose has a phosphate group, the process for producing the fine fibrous cellulose includes a phosphate group introduction step. In the step of introducing a phosphate group, at least one compound selected from compounds capable of introducing a phosphate group (hereinafter also referred to as "compound A") is added to cellulose by reacting with a hydroxyl group possessed by a fiber raw material containing cellulose. It is a step of acting on a fiber raw material containing. Through this step, a phosphate group-introduced fiber is obtained.

In the phosphate group-introducing step according to the present embodiment, the reaction between the fiber material containing cellulose and compound A is performed in the presence of at least one selected from urea and derivatives thereof (hereinafter also referred to as "compound B"). may On the other hand, the reaction between the cellulose-containing fiber raw material and the compound A may be carried out in the absence of the compound B.

An example of the method of allowing the compound A to act on the fiber raw material in the presence of the compound B includes 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. Among these, 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, because the uniformity of the reaction is high. Although the form of the fiber material is not particularly limited, it is preferably in the form of cotton or a thin sheet, for example. The compound A and the compound B can be added to the fiber raw material in the form of a powder, a solution dissolved in a solvent, or a melted state by heating to a melting point or higher. Among these, it is preferable to add in the form of a solution dissolved in a solvent, particularly in the form of an aqueous solution, since the uniformity of the reaction is high. Moreover, the compound A and the compound B may be added simultaneously to the fiber raw material, 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 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 added dropwise to the Further, the necessary amount of compound A and compound B may be added to the fiber raw material, or after adding excessive amounts of compound A and compound B to the fiber raw material, the excess compound A and compound B are removed by pressing or filtering. may be removed.

The compound A used in this embodiment includes a compound having a phosphorus atom and capable of forming an ester bond with cellulose, specifically phosphoric acid or its salts, phosphorous acid or its salts, dehydration condensation Phosphoric acid or a salt thereof, phosphoric anhydride (phosphorus pentoxide), etc. may be mentioned, but are not particularly limited. Phosphoric acid of various purities can be used, for example, 100% phosphoric acid (orthophosphoric acid) or 85% phosphoric acid can be used. Phosphorous acid includes, for example, 99% phosphorous acid (phosphonic acid). Dehydration-condensed phosphoric acid is obtained by condensing two or more molecules of phosphoric acid by dehydration reaction, and examples thereof include pyrophosphoric acid and polyphosphoric acid. Phosphates, phosphites and dehydrated condensed phosphates include lithium salts, sodium salts, potassium salts and ammonium salts of phosphoric acid, phosphorous acid or dehydrated condensed phosphoric acids. It can be a degree of harmony. Among these, the efficiency of introducing a phosphate group is high, the fibrillation efficiency is easily improved in the fibrillation step described later, the cost is low, and it is easy to apply industrially. Sodium salt, potassium salt of phosphate, or ammonium salt of phosphate are preferred, and phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, or ammonium dihydrogen phosphate are more preferred.

The amount of compound A added to the fiber raw material is not particularly limited. For example, when the amount of compound A added is converted to the phosphorus atomic weight, the amount of phosphorus atoms 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 even more preferably 2% by mass or more and 30% by mass or less. By setting the amount of phosphorus atoms 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 amount of phosphorus atoms added to the fiber raw material to be equal to or less than the above upper limit, it is possible to balance the effect of improving the yield and the cost.

Compound B used in this embodiment is at least one selected from urea and derivatives thereof as described above. Compound B includes, for example, urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, and 1-ethylurea.
From the viewpoint of improving the uniformity of the reaction, compound B is preferably used as an aqueous solution. 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, more preferably 10% by mass or more and 400% by mass or less, More preferably, it is 100% by mass or more and 350% by mass or less.

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

In the phosphate group-introducing step, it is preferable to heat-treat the fiber raw material after adding or mixing the compound A or the like to the fiber raw material. As the heat treatment temperature, it is preferable to select a temperature at which the phosphate 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 even more preferably 130° C. or higher and 200° C. or lower. In addition, for the heat treatment, equipment having various heat media can be used. A drying device, a vacuum drying device, an infrared heating device, a far infrared heating device, or a microwave heating device can be used.

In the heat treatment according to the present embodiment, for example, the compound A is added to a thin sheet-like fiber raw material by a method such as impregnation, and then heated, or the fiber raw material and the compound A are heated while kneading or stirring with a kneader or the like. method can be adopted. This makes it possible to suppress concentration unevenness of the compound A in the fiber raw material and to more uniformly introduce phosphate groups to the surface of the cellulose fibers contained in the fiber raw material. This is because when water molecules move to the surface of the fiber material during drying, the dissolved compound A is attracted to the water molecules by surface tension and similarly moves to the surface of the fiber material (that is, the concentration unevenness of the compound A is It is thought that this is due to the fact that it is possible to suppress the occurrence of

In addition, the heating device used for the heat treatment always removes the moisture retained by the slurry and the moisture generated due to the dehydration condensation (phosphorylation) reaction between the compound A and the hydroxyl groups contained in the cellulose etc. in the fiber raw material. It is preferable that the device can be discharged to the outside of the device system. As such a heating device, for example, an air-blowing oven can be used. By constantly draining the water in the device system, it is possible to suppress the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of phosphorylation, and to suppress the acid hydrolysis of the sugar chains 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 1000 seconds or less, and 10 seconds or more and 800 seconds or less, after water is substantially removed from the fiber raw material. is more preferable. In the present embodiment, the introduction amount of the phosphate group can be set within a preferable range by setting the heating temperature and the heating time within appropriate ranges.

The step of introducing a phosphate group may be performed at least once, but may be performed repeatedly two or more times. By performing the phosphate group-introducing step two or more times, many phosphate groups can be introduced into the fiber raw material. In the present embodiment, one example of a preferred aspect is the case where the phosphate group introduction step is performed twice.

The amount of phosphate groups introduced into the fiber raw material is, for example, preferably 0.10 mmol/g or more, more preferably 0.20 mmol/g or more, more preferably 0.50 mmol/g per 1 g (mass) of fine fibrous cellulose. g or more is more preferable, and 1.00 mmol/g or more is particularly preferable. In addition, the amount of phosphate groups introduced into the fiber raw material is, for example, preferably 5.20 mmol/g or less, more preferably 3.65 mmol/g or less per 1 g (mass) of fine fibrous cellulose. It is more preferably 00 mmol/g or less. By setting the amount of the phosphate group to be introduced within the above range, the fiber raw material can be easily made finer, and the stability of the fine fibrous cellulose can be enhanced. Furthermore, by setting the amount of phosphate groups to be introduced within the above range, the content of organic onium ions that can be contained in the fibrous cellulose can be set to an appropriate range, thereby making the fibrous ions for the polyimide resin and the organic solvent The dispersibility of cellulose can be effectively enhanced.

<Carboxy Group Introduction Step>
When the fine fibrous cellulose has a carboxy group, the production process of the fine fibrous cellulose includes a carboxy group introduction step. In the step of introducing a carboxy group, the fiber raw material containing cellulose is subjected to oxidation treatment such as ozone oxidation, oxidation by the Fenton method, TEMPO oxidation treatment, a compound having a carboxylic acid-derived group or a derivative thereof, or a carboxylic acid-derived group. This is done by treating the compound with an acid anhydride or a derivative thereof.

The compound having a carboxylic acid-derived group is not particularly limited. Examples include tricarboxylic acid compounds. Derivatives of compounds having a carboxylic acid-derived group are not particularly limited, but include, for example, imidized acid anhydrides of compounds having a carboxy group and derivatives of acid anhydrides of compounds having a carboxy group. Examples of imidized acid anhydrides of compounds having a carboxy group include, but are not particularly limited to, imidized dicarboxylic acid compounds such as maleimide, succinimide and phthalimide.

The acid anhydride of the compound having a group derived from carboxylic acid is not particularly limited. acid anhydrides; In addition, the acid anhydride derivative of the compound having a group derived from carboxylic acid is not particularly limited. Acid anhydrides in which at least some of the hydrogen atoms are substituted with substituents such as alkyl groups and phenyl groups can be mentioned.

In the carboxyl group introduction step, when the TEMPO oxidation treatment is performed, it is preferable to perform the treatment under the condition of pH 6 or more and 8 or less. Such treatment is also referred to as neutral TEMPO oxidation treatment. Neutral TEMPO oxidation treatment includes, for example, sodium phosphate buffer (pH=6.8), pulp as a fiber raw material, and TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) as a catalyst. This can be done by adding sodium hypochlorite as a nitroxy radical, sacrificial reagent. Furthermore, coexistence of sodium chlorite enables efficient oxidation of aldehydes generated in the process of oxidation to carboxyl groups.

Moreover, the TEMPO oxidation treatment may be performed under the condition that the pH is 10 or more and 11 or less. Such treatment is also called alkali TEMPO oxidation treatment. Alkaline TEMPO oxidation treatment can be performed, for example, by adding a nitroxy radical such as TEMPO as a catalyst, sodium bromide as a cocatalyst, and sodium hypochlorite as an oxidizing agent to pulp as a fiber raw material. .

The amount of carboxyl groups to be introduced into the fiber raw material varies depending on the type of substituent. For example, when carboxyl groups are introduced by TEMPO oxidation, the amount is preferably 0.10 mmol/g or more per 1 g (mass) of fine fibrous cellulose. , is more preferably 0.20 mmol/g or more, still more preferably 0.50 mmol/g or more, and particularly preferably 0.90 mmol/g or more. Also, it is preferably 2.5 mmol/g or less, more preferably 2.20 mmol/g or less, and even more 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. Furthermore, by setting the amount of carboxyl groups to be introduced within the above range, the content of organic onium ions that can be contained in the fibrous cellulose can be set to an appropriate range, thereby increasing the amount of fibrous cellulose relative to polyimide resins and organic solvents. can effectively increase the dispersibility of

<Washing process>
In the method for producing fine fibrous cellulose according to the present embodiment, the anionic group-introduced fiber can be subjected to a washing step, if necessary. The washing step is performed by washing the anionic group-introduced fiber with water or an organic solvent, for example. Moreover, the washing process may be performed after each process described later, and the number of times of washing performed in each washing process is not particularly limited.

<Alkali treatment process>
When producing fine fibrous cellulose, the fiber raw material may be subjected to alkali treatment between the anionic group introduction step and the defibration treatment step described later. The method of alkali treatment is not particularly limited, but includes, for example, a method of immersing the anionic group-introduced fiber in an alkali 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, it is preferable to use, for example, sodium hydroxide or potassium hydroxide as the alkaline compound because of its high versatility. Moreover, 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 water or a polar solvent including a polar organic solvent exemplified by alcohol, and more preferably an aqueous solvent including at least water. As the alkaline solution, for example, an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution is preferable because of its high versatility.

Although the temperature of the alkaline solution in the alkaline treatment step is not particularly limited, it is preferably 5° C. or higher and 80° C. or lower, more preferably 10° C. or higher and 60° C. or lower. The immersion time of the anionic group-introduced fiber in the alkali solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes or more and 30 minutes or less, 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 for example, it is preferably 100% by mass or more and 100000% by mass or less, and 1000% by mass or more and 10000% by mass or less relative to the absolute dry mass of the anionic group-introduced fiber. is more preferable.

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

<Acid treatment process>
When producing fine fibrous cellulose, the fiber raw material may be subjected to an acid treatment between the step of introducing an anionic group and the defibration treatment step described later. For example, the anionic group introduction step, acid treatment, alkali treatment and fibrillation treatment may be performed in this order.

The acid treatment method is not particularly limited, but includes, for example, a method of immersing the fiber raw material in an acidic liquid containing an acid. Although the concentration of the acid liquid used is not particularly limited, it is preferably 10% by mass or less, more preferably 5% by mass or less. Moreover, the pH of the acidic liquid to be used is not particularly limited. Examples of acids contained in the acid solution include inorganic acids, sulfonic acids, and carboxylic acids. Examples of inorganic acids include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, phosphoric acid and boric acid. Examples of sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and the like. Carboxylic acids include, for example, formic acid, acetic acid, citric acid, gluconic acid, lactic acid, oxalic acid, and tartaric acid. 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. 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, 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. is more preferred.

<Fibrillation treatment>
Fine fibrous cellulose is obtained by subjecting the anionic group-introduced fibers to defibration treatment in the fibrillation treatment step. In the defibration treatment process, for example, a fibrillation treatment device can be used. The fibrillation treatment device is not particularly limited, but for example, a high-speed fibrillator, a grinder (stone mill type pulverizer), a high pressure homogenizer, an ultra-high pressure homogenizer, a high pressure impact type pulverizer, a ball mill, a bead mill, a disk refiner, a conical refiner, and a biaxial refiner. A kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, a beater, or the like can be used. Among the above defibration equipment, it is more preferable to use a high-speed fibrillation machine, a high-pressure homogenizer, and an ultrahigh-pressure homogenizer, which are less affected by the grinding media and less likely to cause contamination.

In the fibrillation treatment step, for example, the anionic group-introduced fibers are preferably diluted with a dispersion medium to form a slurry. As the dispersion medium, one or more selected from organic solvents such as water and polar organic solvents can be used. The polar organic solvent is not particularly limited, but 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 and glycerin. 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 mono-n-butyl ether, propylene glycol monomethyl ether and the like. Examples of esters include ethyl acetate and butyl acetate. Aprotic polar solvents include dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP) and the like.

The solid content concentration of the fine fibrous cellulose at the defibration treatment can be appropriately set. Further, the slurry obtained by dispersing the anionic group-introduced fiber in the dispersion medium may contain solids other than the anionic group-introduced fiber, such as urea having hydrogen bonding properties.

(organic onium ion)
The fibrous cellulose-containing resin composition of the present invention contains an organic onium ion as a counter ion for the anionic group of the fine fibrous cellulose. In the present invention, at least part of the organic onium ions are present as counter ions of the fine fibrous cellulose. good. Note that organic onium ions do not form covalent bonds with fibrous cellulose.

The organic onium ion satisfies at least one condition selected from the following (a) and (b).
(a) contains a hydrocarbon group having 5 or more carbon atoms;
(b) The total number of carbon atoms is 17 or more.
That is, the fine fibrous cellulose contains at least one selected from an organic onium ion containing a hydrocarbon group having 5 or more carbon atoms and an organic onium ion having a total carbon number of 17 or more as a counter ion of an anionic group. . By making the organic onium ion satisfy at least one of the conditions selected from (a) and (b) above, the dispersibility of the fine fibrous cellulose in the polyimide resin and the organic solvent can be improved, and the polyimide resin It is possible to enhance the releasability of the molded body from the substrate.

The hydrocarbon group having 5 or more carbon atoms is preferably an alkyl group having 5 or more carbon atoms or an alkylene group having 5 or more carbon atoms, and an alkyl group having 6 or more carbon atoms or an alkylene group having 6 or more carbon atoms more preferably an alkyl group having 7 or more carbon atoms or an alkylene group having 7 or more carbon atoms, and an alkyl group having 10 or more carbon atoms or an alkylene group having 10 or more carbon atoms It is particularly preferred to have Among them, the organic onium ion preferably has an alkyl group having 5 or more carbon atoms, and more preferably an organic onium ion containing an alkyl group having 5 or more carbon atoms and having a total carbon number of 17 or more. preferable.

The organic onium ion is preferably an organic onium ion represented by the following general formula (A).

In general formula (A) above, M is a nitrogen atom or a phosphorus atom, and R ₁ to R ₄ each independently represent a hydrogen atom or an organic group. However, at least one of R ₁ to R ₄ is preferably an organic group having 5 or more carbon atoms, or the total number of carbon atoms of R ₁ to R ₄ is preferably 17 or more.
Among them, M is preferably a nitrogen atom. That is, the organic onium ion is preferably an organic ammonium ion. At least one of R ₁ to R ₄ is preferably an alkyl group having 5 or more carbon atoms, and the total number of carbon atoms of R ₁ to R ₄ is preferably 17 or more.

Examples of such organic onium ions include lauryltrimethylammonium, cetyltrimethylammonium, stearyltrimethylammonium, octyldimethylethylammonium, lauryldimethylethylammonium, didecyldimethylammonium, lauryldimethylbenzylammonium, tributylbenzylammonium, and methyltri-n. - octylammonium, hexylammonium, n-octylammonium, dodecylammonium, tetradecylammonium, hexadecylammonium, stearylammonium, N,N-dimethyldodecylammonium, N,N-dimethyltetradecylammonium, N,N-dimethylhexadecyl ammonium, N,N-dimethyl-n-octadecylammonium, dihexylammonium, di(2-ethylhexyl)ammonium, di-n-octylammonium, didecylammonium, didodecylammonium, didecylmethylammonium, N,N-didodecylmethyl ammonium, polyoxyethylenedodecylammonium, alkyldimethylbenzylammonium, di-n-alkyldimethylammonium, behenyltrimethylammonium, tetraphenylphosphonium, tetraoctylphosphonium, acetonyltriphenylphosphonium, allyltriphenylphosphonium, amyltriphenylphosphonium, benzyl triphenylphosphonium, ethyltriphenylphosphonium, diphenylpropylphosphonium, triphenylphosphonium, tricyclohexylphosphonium, tri-n-octylphosphonium and the like. Examples of the alkyl group in alkyldimethylbenzylammonium and di-n-alkyldimethylammonium include linear alkyl groups having 8 or more and 18 or less carbon atoms.

Incidentally, as shown in the general formula (A), the central element of the organic onium ion is bonded to a total of four groups or hydrogen. In the nomenclature of the organo-onium ions mentioned above, if there are less than four groups attached, the remainder are attached with hydrogen atoms to form the organo-onium ion. For example, in the case of N,N-didodecylmethylammonium, it can be determined from the name that two dodecyl groups and one methyl group are bonded. In this case, hydrogen is bound to the remaining one to form an organic onium ion.

When the organic onium contains O atoms, it is preferable that the mass ratio of C atoms to O atoms (C/O ratio) is as large as possible, for example, C/O>5. By increasing the C/O ratio to greater than 5, a fine fibrous cellulose concentrate is obtained when organic onium ions or compounds that form organic onium ions upon neutralization are added to the fine fibrous cellulose-containing slurry. more likely to be

The molecular weight of the organic onium ion is preferably 2000 or less, more preferably 1800 or less. By setting the molecular weight of the organic onium ion within the above range, the handleability of the fine fibrous cellulose can be enhanced. Further, by setting the molecular weight of the organic onium ion within the above range, it is possible to suppress the decrease in the content of fibrous cellulose in the fibrous cellulose-containing resin composition.

The content of organic onium ions is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, more preferably 2.0% by mass, relative to the total mass of the fibrous cellulose-containing resin composition. % or more is more preferable. Also, the content of organic onium ions is preferably 30% by mass or less, more preferably 20% by mass or less, relative to the total mass of the fibrous cellulose-containing resin composition.

In addition, the content of the organic onium ion in the fibrous cellulose-containing resin composition is preferably an equimolar amount to twice the molar amount of the anionic group contained in the fine fibrous cellulose. Not limited. The content of organic onium ions can be measured by tracing atoms typically contained in organic onium ions. Specifically, the amount of nitrogen atoms is measured when the organic onium ions are ammonium ions, and the amount of phosphorus atoms is measured when the organic onium ions are phosphonium ions. If the fine fibrous cellulose contains nitrogen atoms and phosphorus atoms in addition to the organic onium ions, a method for extracting only the organic onium ions, for example, an extraction operation with an acid, is performed, and then the desired amount of atoms is extracted. You should measure.

(polyimide resin)
The fibrous cellulose-containing resin composition of the present invention contains at least one selected from polyimide resins and polyimide precursors. Examples of polyimide resins include so-called polyimides, which are resins having an imide group in their structure, as typified by polyamideimide, polybenzimidazole, polyimideester, polyetherimide, polysiloxaneimide, and the like. may

A polyimide resin is obtained by imidizing a polyimide precursor obtained by reacting a known diamine and an acid anhydride in the presence of a solvent, using heating or a catalyst.

Examples of diamines include 4,4′-diaminodiphenyl ether, 2′-methoxy-4,4′-diaminobenzanilide, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-amino phenoxy)benzene, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'- diaminobiphenyl, 4,4'-diaminobenzanilide and the like.
Examples of acid anhydrides include pyromellitic anhydride, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride and the like.
In addition, a diamine and an acid anhydride may use only 1 type, respectively, and can also use 2 or more types together.

The reaction between the diamine and the acid anhydride is preferably carried out in an organic solvent. Examples of such organic solvents include dimethylsulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2 -pyrrolidone, hexamethylphosphoramamide, phenol, cresol, γ-butyrolactone and the like. These organic solvents may be used alone or in combination.

A polyimide precursor can be synthesized by a known method, for example, by random polymerization or block polymerization. When synthesizing the polyimide precursor, the temperature of the organic solvent containing diamine and acid anhydride is set to 0 to 100° C., and the solvent solution of the polyimide precursor can be obtained by reacting for 1 minute to 100 hours.

Examples of the polyimide precursor include polyamic acid, polyamic acid salt, polyamic acid alkyl ester, polyamic acid trimethylsilyl ester, mixed solution of tetracarboxylic acid diester and diamine, and the like. Among them, the polyimide precursor is preferably a polyamic acid synthesized from a component containing a tetracarboxylic dianhydride and a diamine.

The polyimide precursor solvent solution is preferably a polyamic acid solution, and a commercially available product may be used. For example, U-Varnish-A and U-Varnish-S manufactured by Ube Industries, Ltd., SPI-200N and SPI-300N manufactured by Nippon Steel Chemical Co., Ltd., Trenice #3000 manufactured by Toray Industries, Ltd., Hitachi Chemical Co., Ltd. PIQ, manufactured by Shin Nippon Chemical Co., Ltd., Ricacoat SN-20, etc. can be used.

A polyimide resin is obtained by imidating a polyimide precursor using heating or a catalyst. When performing the imidization reaction, an imidization catalyst may be added to the solvent solution of the polyimide precursor. Examples of imidization catalysts include imidazole, 2-imidazole, 1,2-dimethylimidazole, 2-phenylimidazole, benzimidazole, isoquinoline, and substituted pyridine.

When heating the polyimide precursor, a casting method may be employed in which a solvent solution of the polyimide precursor is applied onto the supporting base material and dried by heating. In the present invention, when the solvent solution of the polyimide precursor is heated, the solvent solution of the polyimide precursor is previously mixed with fine fibrous cellulose, as described later.

(liquid composition)
The fibrous cellulose-containing resin composition of the present invention may contain an organic solvent. In this case, the organic solvent may be the organic solvent contained in the solvent solution of the polyimide precursor, or may be added separately from the organic solvent contained in the solvent solution of the polyimide precursor. That is, the fibrous cellulose-containing resin composition of the present invention may be a liquid composition, and the liquid composition is a mixture of the fibrous cellulose-containing resin composition described above and an organic solvent. may When the fibrous cellulose-containing resin composition of the present invention is a liquid composition, at least one selected from polyimide resins and polyimide precursors is preferably a solvent solution containing a polyimide precursor, and polyamic acid solution is more preferable.

Organic solvents include, but are not limited to, methanol, ethanol, n-propyl alcohol, isopropyl alcohol (IPA), 1-butanol, m-cresol, glycerin, acetic acid, pyridine, tetrahydrofuran (THF), acetone. , methyl ethyl ketone (MEK), ethyl acetate, aniline, N-methyl-2-pyrrolidone (NMP), dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, hexamethylphosphoramamide, Phenol, γ-butyrolactone, hexane, cyclohexane, benzene, toluene, p-xylene, diethyl ether chloroform and the like can be mentioned. Among them, N-methyl-2-pyrrolidone (NMP), dimethylsulfoxide (DMSO), methyl ethyl ketone (MEK), toluene and methanol are preferably used.

The dielectric constant of the organic solvent at 25° C. is preferably 60 or less, more preferably 50 or less. Since the fine fibrous cellulose of the present invention can exhibit excellent dispersibility even in an organic solvent with a low dielectric constant, the dielectric constant of the organic solvent at 25 ° C. may be 45 or less, It may be 40 or less, or 35 or less.

δp of the Hansen solubility parameter (HSP value) of the organic solvent is preferably 5 MPa ^1/2 or more and 20 MPa ^1/2 or less, more preferably 10 MPa ^1/2 or more and 19 MPa ^1/2 or less. , 12 MPa ^1/2 or more and 18 MPa ^1/2 or less. In addition, δh is preferably 5 MPa ^1/2 or more and 40 MPa ^1/2 or less, more preferably 5 MPa ^1/2 or more and 30 MPa ^1/2 or less, and 5 MPa ^1/2 or more and 20 MPa ^1/2 or less. is more preferred. It is also preferable to simultaneously satisfy the conditions that δp is in the range of 0 MPa ^1/2 to 4 MPa ^1/2 and δh is in the range of 0 MPa ^1/2 to 6 MPa ^1/2 .

The content of the organic solvent is preferably 30% by mass or more, more preferably 40% by mass or more, relative to the total mass of solids contained in the liquid composition. Moreover, the content of the organic solvent is preferably 98% by mass or less, more preferably 97% by mass or less, relative to the total mass of solids contained in the liquid composition. The dispersion medium of the liquid composition is preferably an organic solvent, but may further contain water in addition to the organic solvent.

The solid content concentration in the liquid composition is preferably 1% by mass or more, more preferably 3% by mass or more, relative to the total mass of the liquid composition. Further, the solid content concentration in the liquid composition is preferably 70% by mass or less, more preferably 60% by mass or less, relative to the total mass of the liquid composition.

(Optional component)
The fibrous cellulose-containing resin composition of the present invention may further contain other optional components.

The fibrous cellulose-containing resin composition of the present invention may contain resins other than polyimide and resin precursors as optional components. Although the type of such resin is not particularly limited, examples thereof include thermoplastic resins and thermosetting resins. Specifically, acrylic resins, polycarbonate resins, polyester resins, polyamide resins, silicone resins, fluorine resins, chlorine resins, epoxy resins, melamine resins, phenol resins, polyurethane resins, diallyl Examples include phthalate-based resins, polyolefin-based resins, alcohol-based resins, cellulose derivatives, and precursors of these resins. Examples of cellulose derivatives include carboxymethylcellulose, methylcellulose, and hydroxyethylcellulose.

The fibrous cellulose-containing resin composition of the present invention may contain a water-soluble polymer as an optional component. Examples of water-soluble polymers include xanthan gum, guar gum, tamarind gum, carrageenan, locust bean gum, quince seed, alginic acid, pullulan, carrageenan, thickening polysaccharides such as pectin, cationized starch, raw starch, oxidized Starches such as starch, etherified starch, esterified starch and amylose; glycerins such as glycerin, diglycerin and polyglycerin; hyaluronic acid; metal salts of hyaluronic acid;

When the fibrous cellulose-containing resin composition contains the above-described resins and water-soluble polymers as optional components, the content of such optional components is lower than the total content of the polyimide resin and the polyimide precursor. Few. That is, the main resin component in the fibrous cellulose-containing resin composition is a polyimide resin and/or a polyimide precursor.

Examples of optional components include surfactants, organic ions, coupling agents, inorganic stratiform compounds, inorganic compounds, leveling agents, preservatives, antifoaming agents, organic particles, lubricants, antistatic agents, UV protection agents, Dyes, pigments, stabilizers, magnetic powders, orientation promoters, plasticizers, dispersants, cross-linking agents, fillers, flame retardants, coloring agents, slidability improvers, antioxidants, conductive agents, etc. .

The content of the optional component contained in the fibrous cellulose-containing resin composition is preferably 40% by mass or less, preferably 30% by mass, relative to the total mass of solids contained in the fibrous cellulose-containing resin composition. % or less, more preferably 20 mass % or less.

(Method for producing fibrous cellulose-containing resin composition)
The step of producing a fibrous cellulose-containing resin composition is a step of adding an organic onium ion or a compound that forms an organic onium ion by neutralization to a fine fibrous cellulose-containing slurry to obtain a fine fibrous cellulose concentrate (step a), adding an organic solvent to the fine fibrous cellulose concentrate to obtain a redispersed slurry (step b), and mixing the redispersed slurry and the polyimide precursor (step c). preferable.

In step a, organic onium ions as described above or compounds that form organic onium ions by neutralization are added to the fine fibrous cellulose-containing slurry obtained in the defibration treatment step described above. At this time, the organic onium ions are preferably added as a solution containing the organic onium ions, more preferably as an aqueous solution containing the organic onium ions.

An aqueous solution containing organic onium ions usually contains organic onium ions and counter ions (anions). When preparing an aqueous solution of organic onium ions, if the organic onium ions and the corresponding counterions have already formed a salt, they may be dissolved in water as they are. When preparing an aqueous solution of organic onium ions, if the organic onium ions and the corresponding counter ions have already formed a salt, they are preferably dissolved in water or hot water.

Also, organic onium ions, such as dodecylamine, may be produced only after being neutralized with an acid. In this case, the organic onium ion is obtained by reaction of the acid with a compound which forms the organic onium ion by neutralization. In this case, acids used for neutralization include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as lactic acid, acetic acid, formic acid and oxalic acid. In the aggregating step, a compound that forms an organic onium by neutralization may be directly added to the fine fibrous cellulose-containing slurry to ionize the organic onium using an anionic group contained in the fine fibrous cellulose as a counterion.

The amount of the organic onium ion added is preferably 2% by mass or more, more preferably 10% by mass or more, and even more preferably 50% by mass or more, relative to the total mass of the fine fibrous cellulose. 100% by mass or more is particularly preferable. The amount of the organic onium ion added is preferably 1000% by mass or less with respect to the total mass of the fine fibrous cellulose.
In addition, the number of moles of the organic onium ion to be added is preferably 0.2 times or more the value obtained by multiplying the amount (number of moles) of the anionic group contained in the fine fibrous cellulose by the valence, and preferably 1.0 times. It is more preferably 2.0 times or more, and more preferably 2.0 times or more. The number of moles of organic onium ions to be added is preferably 10 times or less of the value obtained by multiplying the amount (number of moles) of anionic groups contained in the fine fibrous cellulose by the valence.

When the organic onium ion is added and stirred, agglomerates are produced in the fine fibrous cellulose-containing slurry. The aggregates are aggregates of fine fibrous cellulose having organic onium ions as counter ions. A fine fibrous cellulose aggregate (also referred to as a fine fibrous cellulose concentrate) can be recovered by vacuum-filtrating the fine fibrous cellulose-containing slurry in which aggregates are generated.

The obtained fine fibrous cellulose aggregate may be washed with deionized water. By repeatedly washing the fine fibrous cellulose aggregate with deionized water, excess organic onium ions and the like contained in the fine fibrous cellulose aggregate can be removed.

The ratio of the N atom content to the P atom content (N/P value) in the obtained fine fibrous cellulose concentrate is preferably greater than 1.2, more preferably greater than 2.0. more preferred. Moreover, the ratio of the content of N atoms to the content of P atoms in the obtained concentrate of fine fibrous cellulose (value of N/P) is preferably 5.0 or less. The content of P atoms and the content of N atoms in the fine fibrous cellulose concentrate can be appropriately calculated by elemental analysis. For elemental analysis, for example, trace nitrogen analysis, molybdenum blue method, etc. can be performed after appropriate pretreatment. When a composition other than the fine fibrous cellulose concentrate contains P atoms and N atoms, elemental analysis may be performed after the composition and the fine fibrous cellulose concentrate are separated by an appropriate method.

The solid content concentration of the resulting concentrate of fine fibrous cellulose is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. In addition, the upper limit of the solid content concentration of the fine fibrous cellulose concentrate is not particularly limited, and may be 100% by mass.

In step b, an organic solvent is added to the fine fibrous cellulose concentrate to obtain a redispersed slurry. Here, as the organic solvent, the organic solvent described above can be preferably used. As a dispersing device used for dispersing the fine fibrous cellulose concentrate in the organic solvent, for example, the same device as the defibrating treatment device described in the fibrillation treatment can be used. Alternatively, the fine fibrous cellulose concentrate may be dispersed in an organic solvent by subjecting it to ultrasonic treatment.

In step c, the redispersion slurry and the polyimide precursor are mixed. In step c, the polyimide precursor is preferably a solvent solution of a polyimide precursor, more preferably a polyamic acid solution.

In step c, the method of mixing the redispersed slurry and the polyimide precursor is not particularly limited. and the like.

In addition, the manufacturing process of the fibrous cellulose-containing resin composition may further include a process of heating the mixed liquid after the process c. Thereby, the imidization reaction of the polyimide precursor may proceed, and a solid fibrous cellulose-containing resin composition may be obtained. Further, when forming a molded article such as a sheet from the fibrous cellulose-containing resin composition, it is preferable to heat the mixture of the redispersed slurry and the polyimide precursor in the sheet forming process.

(Application)
Applications of the fibrous cellulose-containing resin composition of the present invention are not particularly limited. As an example, a fibrous cellulose-containing resin composition can be used to form a film, which can be used as various sheets. Such a sheet is suitable for use as a light-transmissive substrate for various display devices, various solar cells, and the like. It is also suitable for applications such as substrates for electronic devices, electrical insulating materials for electronic circuits, surface protective films for electrical elements, home appliance members, window materials for various vehicles and buildings, interior materials, exterior materials, and packaging materials. there is Furthermore, it is also suitable for applications in which the sheet itself is used as a reinforcing material, in addition to threads, filters, fabrics, cushioning materials, sponges, abrasives, and the like.

(Molded body)
The present invention also relates to a molded article formed from the fibrous cellulose-containing resin composition described above or the liquid composition described above. In the present invention, since fine fibrous cellulose having excellent compatibility with polyimide resins and organic solvents is used, the molded article has an excellent flexural modulus and is also excellent in strength and dimensional stability. . In addition, the molded article of the present invention is also excellent in transparency. In addition, the preferable range of the content ratio of the fine fibrous cellulose, the polyimide resin, and the organic onium ion in the molded article is the same as the preferable range of the content ratio in the fibrous cellulose-containing resin composition.

Although the shape of the molded article of the present invention is not particularly limited, the molded article is preferably in the form of a sheet, for example. The present invention may also relate to a sheet formed from the fibrous cellulose-containing resin composition described above or the liquid composition described above. When the molded article of the present invention is in the form of a sheet, the sheet preferably has a haze of 20% or less, more preferably 10% or less, and even more preferably 5% or less. Thus, according to the present invention, a highly transparent sheet or molded article can be obtained.

There are no particular limitations on the method of molding the molded article, and injection molding, hot pressure molding, and the like can be employed. Moreover, when forming a molded body from a sheet, it may be molded by a press molding method or a vacuum molding method. In this case, a substrate or a mold may be used when molding the molded article, and after molding, it is preferable to include a step of peeling the molded article from the substrate or releasing the molded article from the mold. That is, the step of producing a molded article includes a step of forming a molded article from the fibrous cellulose-containing resin composition or liquid composition described above using a substrate or a mold, and a step of forming the molded article from the substrate. peeling or releasing from the mold.

When the molded article is in the form of a sheet, the step of producing the sheet includes the steps of applying the above fibrous cellulose-containing resin composition or liquid composition onto a substrate to form a coating film, and heating the coating film. It is preferable to include a step of forming a sheet by pressing the sheet, and a step of peeling the sheet from the substrate. Thus, the sheet obtained in the present invention is a substrate-less sheet peeled from the supporting substrate.

The material of the substrate used in the step of forming the coating film is not particularly limited. Among them, the substrate is preferably a glass substrate or a metal substrate. When using a metal substrate, it is particularly preferable to use a metal substrate made of SUS.

In the coating step, if the viscosity of the fibrous cellulose-containing resin composition or liquid composition is low and the composition spreads on the substrate, a dam is placed on the substrate in order to obtain a sheet with a predetermined thickness and basis weight. A frame for stopping may be fixed and used. The frame for damming is not particularly limited, but it is preferable to select, for example, one that allows easy peeling of the edge of the sheet that adheres after drying. From this point of view, it is preferable to use a molded glass plate, metal plate or polyimide plate.

The coating machine for coating the composition on the substrate is not particularly limited, and for example, a roll coater, gravure coater, die coater, curtain coater, air doctor coater and the like can be used. A die coater, a curtain coater, and a spray coater are particularly preferable because the thickness of the coating (sheet) can be made more uniform.

The temperature of the liquid composition and the ambient temperature when the composition is applied to the substrate are not particularly limited, but are preferably 5° C. or higher and 80° C. or lower, more preferably 10° C. or higher and 60° C. or lower. It is preferably 15° C. or higher and 50° C. or lower, and particularly preferably 20° C. or higher and 40° C. or lower.

In the coating step, the composition is applied so that the finished basis weight of the sheet is preferably 10 g/m ² or more and 100 g/m ² or less, more preferably 20 g/m ² or more and 60 g/m ² or less. Coating on a substrate is preferred. By coating so that the basis weight is within the above range, a sheet having more excellent strength can be obtained.

The coating step includes a step of drying the composition applied onto the substrate. Such a process is also called a curing process. The curing step is not particularly limited, but may be performed by, for example, 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, but for example, a method of drying by heating with hot air, infrared rays, far infrared rays, or near infrared rays (heat drying method), or a method of drying in a vacuum (vacuum drying method) is applied. can do. Although the heat drying method and the vacuum drying method may be combined, the heat drying method is usually applied. Drying with infrared rays, far-infrared rays, or near-infrared rays is not particularly limited. The heating temperature (curing temperature) is preferably 80° C. or higher, more preferably 100° C. or higher. Moreover, the heating temperature (curing temperature) is preferably 200° C. or less. Thus, in the present invention, the curing process of the polyimide resin can be performed at a relatively low temperature, thereby suppressing discoloration and deterioration due to heating.

(Laminate)
The present invention may also relate to a laminate comprising the molded article described above. In this case, the laminate preferably includes a sheet-like molded body, and may be a laminate in which other layers are formed on both sides of the sheet-shaped molded body. It may be a laminate in which another layer is formed on one side of the layer.

Other layers may include resin layers and inorganic layers. The other layer is also preferably a layer containing at least one selected from fine fibrous cellulose and water-soluble polymer.

An adhesive layer may be provided between the molded body and other layers described above. When an adhesive layer is provided between the molded body and another layer, examples of the adhesive constituting the adhesive layer include acrylic resins. Examples of adhesives other than acrylic resins include vinyl chloride resins, (meth)acrylic acid ester resins, styrene/acrylic acid ester copolymer resins, vinyl acetate resins, and vinyl acetate/(meth)acrylic acid ester copolymer resins. Polymer resins, urethane resins, silicone resins, epoxy resins, ethylene/vinyl acetate copolymer resins, polyester resins, polyvinyl alcohol resins, ethylene vinyl alcohol copolymer resins, and rubber emulsions such as SBR and NBR. be done.

Although the thickness of the other layer is not particularly limited, it is preferably 5 μm or more, more preferably 10 μm or more. Also, the thickness of the other layer is preferably 10000 μm or less, more preferably 1000 μm or less. When other layers are formed by a technique such as ALD, which will be described later, the thickness may be 1000 nm or less.

<Resin layer>
The resin layer is a layer containing natural resin or synthetic resin as a main component. Here, the main component refers to a component that is contained in an amount of 50% by mass or more with respect to the total mass of the resin layer. The content of the resin is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and 90% by mass with respect to the total mass of the resin layer. It is particularly preferable that it is above. In addition, the content of the resin may be 100% by mass, or may be 95% by mass or less.

Examples of natural resins include rosin-based resins such as rosin, rosin esters, and hydrogenated rosin esters.

The synthetic resin is preferably at least one selected from, for example, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polyimide resin, polystyrene resin, polyurethane resin and acrylic resin.

The resin constituting the resin layer may be used singly, or a copolymer obtained by copolymerizing or graft-polymerizing a plurality of resin components may be used. Also, it may be used as a blend material in which a plurality of resin components are mixed by a physical process.

<Inorganic layer>
The material constituting the inorganic layer is not particularly limited, but for example, aluminum, silicon, magnesium, zinc, tin, nickel, titanium; or mixtures thereof. From the viewpoint that high moisture resistance can be stably maintained, silicon oxide, silicon nitride, silicon oxycarbide, silicon oxynitride, silicon oxycarbide nitride, aluminum oxide, aluminum nitride, aluminum oxycarbide, aluminum oxynitride, or these Mixtures are preferred.

A method for forming the inorganic layer is not particularly limited. In general, methods for forming thin films are roughly classified into chemical vapor deposition (CVD) and physical vapor deposition (PVD), and either method may be adopted. . Specific examples of the CVD method include plasma CVD using plasma, catalytic chemical vapor deposition (Cat-CVD) in which a material gas is catalytically thermally decomposed using a heated catalyst, and the like. Specific examples of the PVD method include vacuum deposition, ion plating, and sputtering.

Moreover, as a method for forming the inorganic layer, an atomic layer deposition (ALD) method can be employed. The ALD method is a method of forming a thin film in units of atomic layers by alternately supplying raw material gases of elements constituting a film to be formed to a surface on which a layer is to be formed. Although it has the disadvantage of a slow deposition rate, it has the advantage over the plasma CVD method that even surfaces with complicated shapes can be covered cleanly, and a thin film with few defects can be deposited. In addition, the ALD method has the advantage that the film thickness can be controlled on the order of nanometers, and that it is relatively easy to cover a wide surface. Furthermore, the ALD method is expected to improve the reaction rate, lower the temperature of the process, and reduce unreacted gas by using plasma.

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited by the following examples. In the following, Examples 2 and 4 shall be read as Reference Examples 2 and 4, respectively.

<Production Example 1>
[Production of fine fibrous cellulose dispersion liquid A]
As raw material pulp, softwood kraft pulp manufactured by Oji Paper Co., Ltd. (solid content 93% by mass, basis weight 208 g / m ² sheet, defiberized and Canadian standard freeness (CSF) measured according to JIS P 8121 700 ml) It was used.

The raw material pulp was subjected to a phosphorylation 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. A chemical-impregnated pulp was obtained by adjusting as follows. Next, the resulting chemical solution-impregnated pulp was heated in a hot air dryer at 165° C. for 200 seconds to introduce phosphoric acid groups into cellulose in the pulp to obtain phosphorylated pulp.

Then, the obtained phosphorylated pulp was washed. In the washing treatment, a pulp dispersion liquid obtained by pouring 10 L of ion-exchanged water into 100 g (absolute dry mass) of phosphorylated pulp is stirred so that the pulp is uniformly dispersed, and then filtration and dehydration are repeated. gone. The washing was finished when the electric conductivity of the filtrate became 100 μS/cm or less.

The washed phosphorylated pulp was further subjected to the phosphorylation treatment and the washing treatment once in this order.

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

The phosphorylated pulp thus obtained was subjected to infrared absorption spectrum measurement using FT-IR. As a result, absorption due to phosphate groups was observed near 1230 cm ^-1 , confirming that phosphate groups were added to the pulp.

In addition, when the obtained phosphorylated pulp was tested and analyzed with an X-ray diffraction device, it was found that the A typical peak was confirmed, confirming that it had cellulose type I crystals.

Ion-exchanged water was added to the obtained phosphorylated pulp to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated six times with a wet atomization device (Starburst, manufactured by Sugino Machine Co., Ltd.) at a pressure of 200 MPa to obtain a fine fibrous cellulose dispersion liquid A containing fine fibrous cellulose.

X-ray diffraction confirmed that this fine fibrous cellulose maintained cellulose type I crystals. Further, 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 phosphate groups (strongly acidic group amount) measured by the method described later was 2.0 mmol/g.

<Production Example 2>
[Production of fine fibrous cellulose dispersion liquid B]
As raw material pulp, softwood kraft pulp manufactured by Oji Paper Co., Ltd. (solid content 93% by mass, basis weight 208 g / m ² sheet, defiberized and Canadian standard freeness (CSF) measured according to JIS P 8121 700 ml) It was used. This raw material pulp was subjected to TEMPO oxidation treatment as follows.

First, the raw pulp equivalent to 100 parts by mass of dry mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), 10 parts by mass of sodium bromide, and 10000 parts by mass of water distributed in parts. Then, a 13% by mass sodium hypochlorite aqueous solution was added to 10 mmol per 1.0 g of pulp to initiate the reaction. During the reaction, a 0.5 M sodium hydroxide aqueous solution was added dropwise to maintain the pH at 10 or more and 10.5 or less, and the reaction was considered completed when no change in pH was observed.

Then, the obtained TEMPO oxidized pulp was washed. The washing treatment is performed by dehydrating the pulp slurry after TEMPO oxidation to obtain a dehydrated sheet, pouring 5000 parts by mass of ion-exchanged water, stirring to uniformly disperse, and then filtering and dehydrating repeatedly. rice field. The washing was finished when the electric conductivity of the filtrate became 100 μS/cm or less.

In addition, when the obtained TEMPO oxidized pulp was tested and analyzed with an X-ray diffraction device, it was found that the 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 six times with a wet atomization device (Starburst, manufactured by Sugino Machine Co., Ltd.) at a pressure of 200 MPa to obtain a fine fibrous cellulose dispersion liquid B containing fine fibrous cellulose.

X-ray diffraction confirmed that this fine fibrous cellulose maintained cellulose type I crystals. Further, when the fiber width of the fine fibrous cellulose was measured using a transmission electron microscope, it was 3 to 5 nm. The carboxy group content of the TEMPO oxidized pulp measured by the method described later was 1.80 mmol/g.

<Production Example 3>
[Production of fine fibrous cellulose dispersion liquid C]
As raw material pulp, softwood kraft pulp manufactured by Oji Paper Co., Ltd. (solid content 93% by mass, basis weight 208 g / m ² sheet, defiberized and Canadian standard freeness (CSF) measured according to JIS P 8121 700 ml) It was used.

Ion-exchanged water was added to the raw material pulp to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated six times with a wet atomization device (Starburst, manufactured by Sugino Machine Co., Ltd.) at a pressure of 200 MPa to obtain a fine fibrous cellulose dispersion liquid C containing fine fibrous cellulose.

<Example 1>
[Production of fine fibrous cellulose redispersion slurry A]
0.60 g of lactic acid was added to 100 g of a 2.43% by weight N,N-didodecylmethylamine aqueous solution for pre-neutralization, and then added to 100 g of the fine fibrous cellulose dispersion A obtained in Production Example 1. did. When the dispersion was stirred with a disperser for 5 minutes, aggregates were generated in the fine fibrous cellulose dispersion. A fine fibrous cellulose aggregate was obtained by subjecting the fine fibrous cellulose dispersion containing aggregates to filtration under reduced pressure. The resulting fine fibrous cellulose aggregate was washed repeatedly with deionized water to remove excess N,N-didodecylmethylamine, lactic acid, eluted ions, etc. contained in the fine fibrous cellulose aggregate. The fine fibrous cellulose aggregate thus obtained was dried under conditions of 30° C. and a relative humidity of 40% to obtain a fine fibrous cellulose concentrate A. The counterion of the phosphate group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA+). The solid content concentration of the resulting fine fibrous cellulose concentrate A was 93% by mass.

N-methyl-2-pyrrolidone (NMP) was added to the fine fibrous cellulose concentrate so that the content of fine fibrous cellulose was 2.0% by weight. Thereafter, ultrasonic treatment was performed for 10 minutes using an ultrasonic treatment apparatus (UP400S, manufactured by Hielscher) to obtain fine fibrous cellulose redispersed slurry A.

[Production of fine fibrous cellulose/polyimide composite sheet]
After adding the obtained fine fibrous cellulose redispersion slurry A to polyimide varnish (U-varnish-A, manufactured by Ube Industries, Ltd.) so that the polyimide precursor is 90 parts by mass with respect to 10 parts by mass of fine fibrous cellulose. , and zirconia beads of φ1.0 mm were treated with a paint shaker (manufactured by Toyo Seiki Co., Ltd.) for 3 hours to obtain a fine fibrous cellulose-containing resin composition solution having a solid content concentration of 10% by mass.

The resulting fine fibrous cellulose-containing resin composition solution is weighed so that the sheet has a finished basis weight of 100 g/m ² , poured into a glass petri dish or a SUS petri dish, and dried in a hot air dryer at 180°C. After drying for 5 hours, it was peeled off from the glass petri dish or SUS petri dish to obtain a fine fibrous cellulose-containing polyimide sheet.

<Example 2>
Microfibrous Cellulose Dispersion B was used in place of Microfibrous Cellulose Dispersion A. The procedure of Example 1 was repeated except that 0.32 g of lactic acid was added to 100 g of a 1.32% by mass N,N-didodecylmethylamine aqueous solution for neutralization, and then added to the fine fibrous cellulose dispersion B. A fine fibrous cellulose concentrate B, a fine fibrous cellulose redispersion slurry B, a fine fibrous cellulose-containing resin composition solution, and a fine fibrous cellulose-containing polyimide sheet were obtained. The counterion of the carboxy group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The resulting fine fibrous cellulose concentrate had a solid content concentration of 90% by mass.

<Example 3>
Fine fibrous cellulose was prepared in the same manner as in Example 1, except that the obtained fine fibrous cellulose redispersed slurry A was added to the polyimide varnish so that the polyimide precursor was 95 parts by mass with respect to 5 parts by mass of fine fibrous cellulose. A cellulose concentrate A, a fine fibrous cellulose redispersion slurry A, a fine fibrous cellulose-containing resin composition solution, and a fine fibrous cellulose-containing polyimide sheet were obtained.

<Example 4>
Fine fibrous cellulose was prepared in the same manner as in Example 2, except that polyimide varnish was added to the obtained fine fibrous cellulose redispersion slurry B so that the polyimide precursor was 95 parts by mass with respect to 5 parts by mass of fine fibrous cellulose. A cellulose concentrate B, a fine fibrous cellulose redispersion slurry B, a fine fibrous cellulose-containing resin composition solution, and a fine fibrous cellulose-containing polyimide sheet were obtained.

<Comparative Example 1>
The fine fibrous cellulose dispersion liquid A obtained in Production Example 1 was dried under conditions of 30°C and a relative humidity of 40% to obtain a fine fibrous cellulose concentrate. N-methyl-2-pyrrolidone (NMP) was added so that the content of fine fibrous cellulose was 2.0% by weight. Thereafter, ultrasonic treatment was performed for 10 minutes using an ultrasonic treatment apparatus (UP400S, manufactured by Hielscher) to obtain a fine fibrous cellulose redispersed slurry. A fine fibrous cellulose-containing resin composition solution and a fine fibrous cellulose-containing polyimide sheet were obtained in the same manner as in Example 1 using the obtained fine fibrous cellulose redispersed slurry. In addition, the fine fibrous cellulose-containing polyimide sheet could not be peeled off from the glass petri dish and the SUS petri dish.

<Comparative Example 2>
A fine fibrous cellulose concentrate and a fine fibrous cellulose redispersion were prepared in the same manner as in Comparative Example 1, except that the fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A. A slurry, a resin composition solution containing fine fibrous cellulose and a polyimide sheet containing fine fibrous cellulose were obtained. In addition, the fine fibrous cellulose-containing polyimide sheet could not be peeled off from the glass petri dish and the SUS petri dish.

<Comparative Example 3>
A fine fibrous cellulose concentrate and a fine fibrous cellulose redispersion were prepared in the same manner as in Comparative Example 1, except that the fine fibrous cellulose dispersion C obtained in Production Example 3 was used instead of the fine fibrous cellulose dispersion A. A slurry, a resin composition solution containing fine fibrous cellulose and a polyimide sheet containing fine fibrous cellulose were obtained. In addition, the fine fibrous cellulose-containing polyimide sheet could not be peeled off from the glass petri dish and the SUS petri dish.

<Comparative Example 4>
A resin composition solution and a polyimide sheet were obtained in the same manner as in Comparative Example 1, except that the fine fibrous cellulose redispersion slurry was not added to the polyimide varnish. The polyimide sheet could not be peeled off from the glass petri dish and the SUS petri dish.

<Evaluation>
[Measurement of phosphate group content]
The phosphate group content of the fine fibrous cellulose is obtained by diluting a fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content is 0.2% by mass. The cellulose-containing slurry was treated with an ion-exchange resin and then titrated with an alkali for measurement.
The ion-exchange resin treatment is carried out by adding 1/10 by volume of a strongly acidic ion-exchange resin (Amberjet 1024; Organo Co., Ltd., conditioned) to the fibrous cellulose-containing slurry and shaking for 1 hour. , by pouring it onto a mesh with an opening of 90 μm to separate the resin and the slurry.
In addition, titration with an alkali is carried out by adding a 0.1 N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry after treatment with an ion exchange resin, and adding 50 μL each time once every 30 seconds. This was done by measuring the change in the value of The amount of phosphate groups (mmol/g) is obtained by dividing the alkali amount (mmol) required in the region corresponding to the first region shown in FIG. 1 among the measurement results by the solid content (g) in the slurry to be titrated. calculated by

[Measurement of carboxy group content]
The amount of carboxyl groups in the fine fibrous cellulose is fibrous cellulose prepared by diluting a fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content is 0.2% by mass. The contained slurry was treated with an ion-exchange resin and then titrated with an alkali for measurement.
The ion-exchange resin treatment is carried out by adding 1/10 by volume of a strongly acidic ion-exchange resin (Amberjet 1024; Organo Co., Ltd., conditioned) to the fibrous cellulose-containing slurry and shaking for 1 hour. , by pouring it onto a mesh with an opening of 90 μm to separate the resin and the slurry.
In addition, titration using an alkali was carried out by adding 50 μL of a 0.1N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry after treatment with an ion-exchange resin once every 30 seconds, while increasing the electrical conductivity of the slurry. It was carried out by measuring the change in value. The amount of carboxyl groups (mmol/g) is obtained by dividing the alkali amount (mmol) required in the region corresponding to the first region shown in FIG. 2 among the measurement results by the solid content (g) in the slurry to be titrated. Calculated.

[Peelability from substrate]
The fine fibrous cellulose-containing resin composition solution is weighed so that the sheet has a finished basis weight of 100 g/m ² , poured into a glass petri dish or a SUS petri dish, and dried in a hot air dryer at 180°C for 5 hours. let me After that, the sheet was peeled off from the glass petri dish or the SUS petri dish. The peelability was evaluated from the state of the sheet at that time.
◯: The sheet has no cracks or tears, and can be peeled off from the substrate.
x: The sheet adheres to the base material and cannot be peeled off from the base material, or the sheet is cracked or torn when peeled off.

The fine fibrous cellulose-containing polyimide sheets obtained in Examples were excellent in releasability from the substrate. On the other hand, the fine fibrous cellulose-containing polyimide sheet obtained in Comparative Example could not be peeled off from the substrate.

When polyether ammonium was used as the counter ion for the anionic group, it was difficult to obtain aggregates of fine fibrous cellulose.

Claims (8)

A fibrous cellulose having a fiber width of 1000 nm or less and having an anionic group, at least one selected from polyimide resins and polyimide precursors, and an organic onium ion as a counterion of the anionic group,
The anionic group is a phosphate group or a substituent derived from a phosphate group,
The organic onium ion is a fibrous cellulose-containing resin composition that satisfies at least one condition selected from the following (a) and (b);
(a) contains a hydrocarbon group having 5 or more carbon atoms;
(b) The total number of carbon atoms is 17 or more. The fibrous cellulose-containing resin composition according to claim 1, wherein the organic onium ion is an organic ammonium ion. 3. The fibrous cellulose-containing resin composition according to claim 1, wherein the fibrous cellulose has an anionic group content of 0.50 mmol/g or more. A liquid composition obtained by mixing the fibrous cellulose-containing resin composition according to any one of claims 1 to 3 and an organic solvent. A molded article formed from the fibrous cellulose-containing resin composition according to any one of claims 1 to 3 or the liquid composition according to claim 4. The molded article according to claim 5, which is in the form of a sheet. A step of forming a molded body from the fibrous cellulose-containing resin composition according to any one of claims 1 to 3 or the liquid composition according to claim 4 using a substrate or a mold; ,
and a step of releasing the molded article from the substrate or releasing the molded article from the mold. A step of applying the fibrous cellulose-containing resin composition according to any one of claims 1 to 3 or the liquid composition according to claim 4 onto a substrate to form a coating film;
a step of heating the coating film to form a sheet;
and a step of peeling the sheet from the base material.

Images