JP2022045900A - Modifier for cellulose nanofiber, production method of modified cellulose nanofiber, modified cellulose nanofiber, and fiber-reinforced composite material - Google Patents

Abstract

To provide a modifier for cellulose nanofibers capable of obtaining cellulose nanofibers excellent in dispersibility to a polyolefin resin.SOLUTION: A modifier for cellulose nanofibers, including a partially neutralized product (XC) of an acid-modified polyolefin (X) and a base (C) is such that: the (X) contains as the constitution materials, a polyolefin (A) having a carbon-carbon double bond, and an unsaturated (poly)carboxylic acid (anhydride)(B); the (A) contains an ethylene and an α-olefin (carbon number 3-8) as the constitution monomers; and a weight ratio [ethylene/α-olefin] of the ethylene and the α-olefin is 3/97-50/50.SELECTED DRAWING: None

Description

The present invention relates to a modifier for cellulose nanofibers, a method for producing modified cellulose nanofibers, modified cellulose nanofibers and a fiber-reinforced composite material.

Cellulose nanofibers are ultrafine fibers having a fiber diameter of nano-order, or fiber aggregates thereof, and have a very large surface area, and application to composite materials such as fiber-reinforced resins is being studied by taking advantage of their characteristics.
As a method for improving the dispersibility of cellulose nanofibers in a matrix resin of a fiber-reinforced resin, a method of using a polyalkylene oxyside type surfactant as a surface treatment agent is known (for example, Patent Document 1).

However, when the surface treatment agent of Patent Document 1 is used and the polyolefin resin is used as the matrix resin of the reinforcing fiber resin, the dispersibility of the cellulose nanofibers in the polyolefin resin is not sufficient, and the mechanical properties are as expected. Was not expressed.

Japanese Unexamined Patent Publication No. 2020-83913

An object of the present invention is to provide a modifier for cellulose nanofibers capable of obtaining cellulose nanofibers having excellent dispersibility in a polyolefin resin.

The present inventors have arrived at the present invention as a result of studies for achieving the above object.
That is, the present invention contains a (partially) neutralized product (XC) of an acid-modified polyolefin (X) and a base (C), wherein the (X) is a polyolefin (A) having a carbon-carbon double bond. It contains unsaturated (poly) cellulose acid (anhydride) (B) as a constituent raw material, and (A) contains ethylene and α-olefin having 3 to 8 carbon atoms as a constituent monomer, and ethylene and α- A modifier for cellulose nanofibers having a weight ratio [ethylene / α-olefin] of 3/97 to 50/50 with an olefin; a modification having a step of mixing the cellulose nanofibers and the modifier for cellulose nanofibers. A method for producing quality cellulose nanofibers; a modified cellulose nanofiber in which the modifier for cellulose nanofibers is attached to the surface of the cellulose nanofibers; a fiber-reinforced composite material containing the modified cellulose nanofibers.

The modifier for cellulose nanofibers of the present invention can obtain cellulose nanofibers having excellent dispersibility in a polyolefin resin.

The first modifier for cellulose nanofibers according to the present invention contains a (partially) neutralized product (XC) of an acid-modified polyolefin (X) and a monovalent base (C), wherein the (X) is: A polyolefin (A) having a carbon-carbon double bond and an unsaturated (poly) carboxylic acid (anhydrous) (B) are contained as constituent raw materials, and the (A) is ethylene and an α-olefin having 3 to 8 carbon atoms. As a constituent monomer, the weight ratio of ethylene to α-olefin [ethylene / α-olefin] is 3/97 to 50/50.
In the present invention, the "(partially) neutralized product of the acid-modified polyolefin (X) and the monovalent base (C)" is "the monovalent all or part of the carboxyl group derived from the acid-modified polyolefin (X)". It means "a compound obtained by neutralizing with a base (C)". Further, "unsaturated (poly) carboxylic acid (anhydrous)" means "at least one selected from the group consisting of unsaturated monocarboxylic acid, unsaturated polycarboxylic acid and unsaturated polycarboxylic acid anhydride". ..

<Polyolefin (A) having a carbon-carbon double bond>
A carbon-carbon double bond (hereinafter, simply referred to as a double bond) which is a constituent raw material of the acid-modified polyolefin (X) constituting the (partial) neutralizer (XC) contained in the modifier for cellulose nanofibers of the present invention. The polyolefin (A) having (may be abbreviated) is an acid-modified polyolefin containing ethylene and an α-olefin having 3 to 8 carbon atoms as a constituent monomer.
Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.
Two or more kinds of the above-mentioned α-olefins may be used in combination, or one kind may be used alone, and it is preferable to use one kind alone.
Of the above α-olefins, propylene is preferable from the viewpoint of mechanical strength and industry, and it is more preferable to use propylene alone.

The weight ratio [ethylene / α-olefin] of ethylene, which is a constituent monomer of the polyolefin (A) having a carbon-carbon double bond, to α-olefin having 3 to 8 carbon atoms is 3/97 to 50/50. It is preferably 5/95 to 40/60, and more preferably 10/90 to 30/70.
When the weight ratio [ethylene / α-olefin] is less than 3/97, it is difficult to obtain sufficient dispersibility of the modified cellulose nanofibers modified with the modifying agent for cellulose nanofibers with respect to the polyolefin resin, and 50/50. If it exceeds, it becomes difficult to obtain a fiber-reinforced composite material having excellent mechanical strength.
The weight ratio [ethylene / α-olefin] can be calculated by, for example, ¹ H-NMR. The weight ratio of ethylene of (A) to α-olefin having 3 to 8 carbon atoms is the weight ratio of ethylene of the high-molecular-weight polyolefin (A0) described later, which is the raw material of (A), to α-olefin having 3 to 8 carbon atoms. Since the value is the same as the weight ratio of the above (A0) in which the weight ratio [ethylene / α-olefin] is in a predetermined range, the weight ratio of the polyolefin (A) having a carbon-carbon double bond [A Ethylene / α-olefin] can be adjusted.

The polyolefin (A) having a carbon-carbon double bond may be composed of a monomer (other monomer) other than ethylene and α-olefin having 3 to 4 carbon atoms. In that case, the weight ratio of the other monomers is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% by weight, based on the weight of all the monomers constituting the above (A). % Or less.
Examples of the above-mentioned other monomers include α-olefins having 9 to 30 carbon atoms [may be abbreviated as C] (for example, 1-decene and 1-dodecene) and C4 to 30 other than α-olefins. Examples thereof include unsaturated monomers (for example, olefins such as 2-butene and isobutene, and vinyl monomers such as styrene, acrylonitrile, acrylamide and vinyl acetate).

The number average molecular weight (Mn) of the polyolefin (A) having a carbon-carbon double bond is preferably 800 to 50,000, more preferably 1,500 to 40, from the viewpoint of mechanical strength and storage stability. It is 000, particularly preferably 2,000 to 30,000.

The Mn of the polyolefin (A) having a carbon-carbon double bond can be measured by GPC (gel permeation chromatography) under the following conditions. Further, Mn and the weight average molecular weight (Mw) in the present invention are also measured under the same conditions.
Equipment: High temperature gel permeation chromatograph
["Alliance GPC V2000", manufactured by Waters Corp.]
Detection device: Refractive index detector Solvent: Ortodichlorobenzene Reference substance: Polystyrene Sample concentration: 3 mg / ml
Column stationary phase: PLgel 10 μm, MIXED-B 2 in series
[Manufactured by Polymer Laboratories Co., Ltd.]
Column temperature: 135 ° C

The number of carbon-carbon double bonds per 1000 carbon atoms in the polyolefin (A) having a carbon-carbon double bond [the number of carbon-carbon double bonds in the molecular end and / or molecular chain of (A) above. ] Is preferably 0.5 to 20 and more preferably 1.5 to 18 from the viewpoint of reactivity with the unsaturated (poly) carboxylic acid (anhydrous) (B) described later and productivity. , Particularly preferably 2 to 15.
The number of double bonds in the above (A) can be obtained from the spectrum of the ¹ H-NMR (nuclear magnetic resonance) spectroscopy of the above (A). That is, the integrated value derived from the hydrogen atom attached to the carbon atom constituting the double bond at 4.5 to 6 ppm of (A), which belongs to the peak in the spectrum, and the carbon atom constituting the (A). From the total of the integrated values derived from all the hydrogen atoms bonded to, the relative value of the number of double bonds in (A) and the number of carbons in (A) is obtained, and the value per 1,000 carbons in (A) is obtained. Calculate the number of double bonds at the end of the molecule and / or in the molecular chain. The number of double bonds in the examples was calculated from this measurement method.

The isotacticity of the α-olefin unit chain portion of the polyolefin (A) having a carbon-carbon double bond is stable when the modifier for cellulose nanofibers is an aqueous dispersion and the mechanical of the fiber-reinforced composite material. From the viewpoint of strength and the like, it is preferably 1 to 50%, more preferably 5 to 45%, and particularly preferably 10 to 40%.
In the present invention, the α-olefin unit chain portion means a chain portion composed of only α-olefin.
The isotacticity of the α-olefin unit chain portion of the polyolefin (A) having a carbon-carbon double bond is a value close to the isotacticity of the α-olefin unit chain portion of the acid-modified polyolefin (X) described later. Therefore, the isotacticity of the acid-modified polyolefin (X) is adjusted by selecting the isotacticity of the (A) as a raw material.
Further, since the isotacticity of (A) is a value close to the isotacticity of the high molecular weight polyolefin (A0) described later as the raw material of (A), the isotacticity of (A0) is selected. By doing so, the isotacticity of (A) can be adjusted.
It is known that the isotacticity of the high molecular weight polyolefin (A0) can be adjusted by selecting the polymerization conditions such as the catalyst used for the polymerization of the above (A0), and the high molecular weight polyolefin having various isotacticities. Is commercially available and available.

The isotacticity can be calculated using ¹³ C-NMR (nuclear magnetic resonance spectroscopy). In general, the side chain alkyl groups of the α-olefin unit chain moiety are on both sides (triplet, triad), on both sides of the triplet (quintuplet, pentad), and on both sides of the quintuplet (seven-strand). It is known that peaks are observed at different chemical shifts under the influence of the configuration (meso or racemic) up to the degree of child, heptad), and the evaluation of stereoregularity is generally performed for pentad. , The isotacticity in the present invention can also be calculated based on the evaluation of the pentad.
For example, when the α-olefin is propylene, each peak (H) of the pentad and the isotactic in which the pentad is formed only by the meso structure for the carbon peak derived from the side chain methyl group in the propylene obtained by ¹³ C-NMR. Assuming that the peak (Ha) is derived from the methyl group in propylene, the isotacticity is calculated by the following formula.
Isotactivity (%) = [(Ha) / Σ (H)] × 100 (1)
However, in the equation, Ha is the peak height of the isotactic (pentad is formed only by the meso structure) signal, and H is the peak height of the pentad.
The isotacticity of the α-olefin unit chain portion of (X) described later can also be measured in the same manner as described above.

Examples of the method for producing the polyolefin (A) having a carbon-carbon double bond include a high molecular weight method (a method of thermally decomposing the polyolefin (A0) (hereinafter, may be referred to as a thermal decomposing method)). The Mn of the high molecular weight polyolefin (A0) is preferably 60,000 to 400,000, more preferably 80,000 to 250,000.

The heat-decomposing method includes a method of heat-decomposing a high-molecular-weight polyolefin (A0) in the absence of an organic peroxide at, for example, 300 to 450 ° C. for 0.5 to 10 hours (method 1), and an organic peroxide. [For example, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane], for example, a method of heat-decomposing at 180 to 300 ° C. for 0.5 to 10 hours (method 2) and the like are included. Is done.
Of these, from the viewpoint of modification efficiency and the like, it is preferable to obtain one having a larger number of double bonds in the molecular terminal and / or the molecular chain (method 1).

When a polyolefin (A) having a carbon-carbon double bond is obtained by thermal decomposing, the higher the thermal decomposing temperature, the larger the number of double bonds per 1000 carbon atoms, and the longer the thermal decomposing time, the more carbon atoms. The number of double bonds per 1000 is increased.
Further, the smaller the Mn of the high molecular weight polyolefin (A0), the smaller the Mn of the (A), the higher the heat decomposing temperature, the smaller the Mn of the (A), and the longer the heat decomposing time, the smaller the (A). ) Mn becomes smaller.

<Unsaturated (poly) carboxylic acid (anhydride) (B)>
An unsaturated (poly) carboxylic acid (anhydride) (B) which is a constituent raw material of the acid-modified polyolefin (X) constituting the (partially) neutralized product (XC) contained in the modifier for cellulose nanofibers of the present invention. Examples thereof include (poly) carboxylic acid (anhydride) having 3 to 30 carbon atoms having one polymerizable unsaturated group. The number of carbon atoms in the unsaturated (poly) carboxylic acid (anhydride) (B) is the total number of carbon atoms in the entire compound.

Among the unsaturated (poly) carboxylic acid (anhydride) (B), the unsaturated monocarboxylic acid is an aliphatic monocarboxylic acid having 3 to 24 carbon atoms (acrylic acid, methacrylic acid, α-ethylacrylic acid, croton). Acids, isocrotonic acid, etc.) and alicyclic monocarboxylic acids with 6 to 24 carbon atoms (carbon cyclohexene carboxylic acid, etc.), and unsaturated poly (2 to 3 or more carbon atoms) carboxylic acids (anhydrides, etc.) ) Is unsaturated dicarboxylic acid (anhydride) [aliphatic dicarboxylic acid (anhydride) having 4 to 24 carbon atoms (maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and these anhydrides, etc.) , Alicyclic dicarboxylic acid (anhydride) having 8 to 24 carbon atoms (cyclohexendicarboxylic acid, cycloheptendicarboxylic acid, bicycloheptendicarboxylic acid, methyltetrahydrophthalic acid, and anhydrides thereof), etc.], Unsaturated tricarboxylic acid (anhydride) [Adilide tricarboxylic acid (anhydride) with 5 to 24 carbon atoms (aconytic acid, 3-butene-1,2,3-tricarboxylic acid, 4-pentene-1,2,4- Tricarboxylic acids (and their anhydrides, etc.), and alicyclic tricarboxylic acids (anhydrides) with 9 to 24 carbon atoms (4-cyclohexene-1,2,3-tricarboxylic acid, 4-cycloheptene-1,2,3). -Tricarboxylic acids and their anhydrides, etc.)] and the like. In the above (B), one type may be used alone, or two or more types may be used in combination.
Of the above (B), unsaturated dicarboxylic acid anhydride is preferable, and maleic anhydride is more preferable, from the viewpoint of reactivity with the polyolefin (A) having a carbon-carbon double bond, storage stability and mechanical strength. It is an acid.

<Acid-modified polyolefin (X)>
The acid-modified polyolefin (X) constituting the (partially) neutralized product (XC) contained in the modifier for cellulose nanofibers of the present invention is unsaturated (unsaturated) with the polyolefin (A) having a carbon-carbon double bond. Poly) Carboxylic acid (anhydride) (B) is included as a constituent raw material.
The acid-modified polyolefin (X) contains the polyolefin (A) having a carbon-carbon double bond and an unsaturated (poly) carboxylic acid (anhydride) (B) in the absence or presence of a radical initiator. It can be obtained by reacting.

When the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly) carboxylic acid (anhydrous) (B) are reacted in the absence or presence of a radical initiator, the carbon-carbon dicarbonate is used. The weight ratio [(A) / (B)] of the polyolefin (A) having a double bond and the unsaturated (poly) carboxylic acid (anhydrous) (B) is such that the modifier for cellulose nanofibers is an aqueous dispersion. From the viewpoint of stability in the case of the above and the mechanical strength of the fiber-reinforced composite material, it is preferably 80/20 to 99.5 / 0.5, and more preferably 90/10 to 99/1.

The acid-modified polyolefin (X) is required for the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly) carboxylic acid (anhydrous) (B) in the presence of the radical initiator (f). Organic solvents with 3 to 18 carbon atoms [eg hydrocarbons (hexane, heptane, octane, dodecane, benzene, toluene and xylene, etc.), halogenated hydrocarbons (di-, tri-, or tetrachloroethane, and dichlorobutane, etc.)). , Ketone (acetone, methyl ethyl ketone, di-t-butyl ketone, etc.), and ether (ethyl-n-propyl ether, di-n-butyl ether, di-t-butyl ether, dioxane, etc.), etc.] are added and reacted. It is preferable that the product is obtained by the above-mentioned.
As the radical initiator (f), known ones can be used, and from the viewpoint of the reactivity between the (A) and the (B), the azo initiator (azobisisobutyronitrile) is preferable. Etc.), a peroxide initiator (dicumyl peroxide, etc.), and a peroxide initiator is more preferable.

In the reaction between the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly) carboxylic acid (anhydrous) (B), the reaction temperature is not the same as that of the polyolefin (A) having a carbon-carbon double bond. From the viewpoint of reactivity with saturated (poly) carboxylic acid (anhydrous) (B), the temperature is preferably 100 to 270 ° C, more preferably 120 to 250 ° C, and particularly preferably 130 to 240 ° C.

The acid-modified polyolefin (X) constituting the (partially) neutralized product (XC) contained in the modifier for cellulose nanofibers of the present invention preferably satisfies the following requirements (1) to (3).
Requirements (1) The acid value is 1 to 100 mgKOH / g.
Requirement (2) The number average molecular weight (Mn) is 1,000 to 60,000.
Requirement (3) The isotacticity of the α-olefin unit chain portion is 1 to 50%.

Requirement (1):
The acid value of the acid-modified polyolefin (X) is preferably 1 to 100 mgKOH / g (hereinafter, only numerical values are shown), more preferably 3 to 75, and particularly preferably 5 to 5 from the viewpoint of modification efficiency of cellulose nanofibers. It is 50.
The acid value here is a value obtained by measuring according to the following procedures (i) to (iii) according to JIS K0070.
(I) Dissolve 1 g of (X) in 100 g of xylene whose temperature has been adjusted to 100 ° C.
(Ii) Titration with 0.1 mol / L potassium hydroxide ethanol solution [trade name "0.1 mol / L ethanolic potassium hydroxide solution", manufactured by Wako Pure Chemical Industries, Ltd.] using phenolphthalein as an indicator at the same temperature. I do.
(Iii) The acid value (unit: mgKOH / g) is calculated by converting the amount of potassium hydroxide required for titration into mg.
Since an ethanol solution is used for the titration in the above measurement, when an unsaturated polycarboxylic acid anhydride is used as a constituent material of the (partially) neutralized product (XC), the acid possessed by the above (X) is used. The anhydride group is hydrolyzed with ethanol to form a half ester. Therefore, the result that the acid value of one acid anhydride group and the acid value of one carboxyl group are equivalent can be obtained. The acid value in the examples was measured by this measuring method.
The acid value is the number of double bonds of the (A) used in the reaction between the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly) carboxylic acid (anhydrous) (B). It can be adjusted by selecting the weight of (A), the type and weight of unsaturated (poly) carboxylic acid (anhydrous) (B).

Requirement (2):
The Mn of the acid-modified polyolefin (X) is preferably 1,000 to 60,000, more preferably 2,000 to 50,000, and particularly preferably 3,000 to 40, from the viewpoint of mechanical strength and focusing property. It is 000.
The Mn of the acid-modified polyolefin (X) is the Mn of the (A) used in the reaction between the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly) carboxylic acid (anhydride) (B). , The type and weight of the unsaturated (poly) carboxylic acid (anhydride) (B), and the reaction conditions between the (A) and the (B) can be adjusted.

Requirement (3):
The isotacticity of the α-olefin unit chain portion of the acid-modified polyolefin (X) is preferably 1 to 50%, more preferably 5 to 45%, and particularly preferably 10 from the viewpoint of focusing and storage stability. ~ 40%.
As described above, the isotacticity of the α-olefin unit chain portion of the acid-modified polyolefin (X) is close to the isotacticity of the polyolefin (A) having a carbon-carbon double bond and the high molecular weight polyolefin (A0). Since it is a value, it can be adjusted by selecting the isotacticity of (A) and (A0).

<(Partial) Neutralizer (XC)>
The (partial) neutralized product (XC) contained in the modifier for cellulose nanofibers of the present invention is contained in the (partial) of the carboxyl group derived from the acid-modified polyolefin (X) and the monovalent base (C). It is a Japanese product.
The carboxyl group derived from the acid-modified polyolefin (X) is a carboxyl introduced by the reaction of the polyolefin (A) having a carbon-carbon double bond with an unsaturated (poly) carboxylic acid (anhydrous) (B). The (partially) neutralized product (XC) is a group and an acid anhydride group, and at least a part of the carboxyl group and the acid anhydride group is neutralized with a monovalent base (C).

The neutralized product (XC) is based on the number of moles of the carboxyl group derived from the acid-modified polyolefin (X) from the viewpoints of the dispersibility of the aqueous dispersion described later and the mechanical strength of the fiber-reinforced composite material described later. The ratio (γ) of the number of moles of the valent base (C) is preferably 10 to 100%, more preferably 20 to 90%, and particularly preferably 30 to 80%.
Hereinafter, the ratio (γ) of the number of moles of the monovalent base (C) based on the number of moles of the carboxyl group derived from the acid-modified polyolefin (X) is referred to as the neutralization rate (%).
The neutralization rate (%) is calculated as follows using the acid value of the acid-modified polyolefin (X) and its weight, and the base value (alkali value) (mgKOH / g) of the monovalent base (C) and its weight. It can be calculated by the formula. When calculating the number of moles of the carboxyl group of the acid-modified polyolefin (X) used in the calculation of the neutralization rate (%), if the acid-modified polyolefin (X) has an acid anhydride group, 1 mol. Calculated as having 2 mol of carboxyl group per acid anhydride group.
Neutralization rate (%) = number of moles of monovalent base (C) / number of moles of carboxyl group (mol) of acid-modified polyolefin (X) x 100
As the number of moles of the carboxyl group of the acid-modified polyolefin (X), the value calculated by the following formula is used.
The number of moles of carboxyl groups (mol) of the acid-modified polyolefin (X) = the weight (g) of the acid-modified polyolefin (X) × the acid value (mgKOH / mgKOH /) of the acid-modified polyolefin (X) titrated using an aqueous potassium hydroxide solution. g) / (56.1 × 1000)
The acid value of the acid-modified polyolefin (X) titrated with an aqueous potassium hydroxide solution is measured by the following method.
(I) 1 g of the polymer (X) is dissolved in 30 g of THF whose temperature has been adjusted to 60 ° C.
(Ii) While maintaining 60 ° C., using phenolphthalein as an indicator, with a 0.1 mol / L potassium hydroxide aqueous solution [trade name “0.1 mol / L potassium hydroxide solution”, manufactured by Wako Pure Chemical Industries, Ltd.]. Perform titration.
When the polymer (X) has an acid anhydride group, it may take time for potassium hydroxide to react with the acid anhydride group. Therefore, it takes about 30 seconds after the potassium hydroxide is added dropwise. Make sure that the color change due to the above does not disappear, and use it as the end point of the titration.
(Iii) The acid value (unit: mgKOH / g) is calculated by converting the amount of potassium hydroxide required for titration into mg.

<Monovalent base (C)>
The monovalent base (C) constituting the (partially) neutralized product (XC) contained in the modifier for cellulose nanofibers of the present invention is monoamine {monoalkylamine having an alkyl group having 1 to 10 carbon atoms. (Methylamine, ethylamine, etc.), Dialkylamine (dimethylamine, diethylamine, methylethylamine, etc.) in which the number of carbon atoms of the alkyl group is 1 to 10 independently, and the number of carbon atoms in the alkyl group are 1 to 10 independently. Certain trialkylamines (trimethylamine, triethylamine, trimethylamine, dimethylbutylamine, etc.), amino alcohols with 1 to 30 carbon atoms (ethanolamine, propanolamine, isopropanolamine, diethanolamine, trimethanolamine, triethanolamine, tripropanolamine, dimethyl, etc.) Aminoethanol, dimethylaminopropanol, etc.), heterocyclic amines (morpholin, etc.), etc.}, ammonia, and alkali metal hydroxides (sodium hydroxide, potassium hydroxide, etc.).
Of the above bases (C), monoamines are preferable, trialkyl (alkyls having 1 to 4 carbon atoms independently) amines are preferable, and triethylamines are particularly preferable, from the viewpoint of focusing property.

The (partial) neutralized product (XC) can be obtained by mixing the acid-modified polyolefin (X) and the base (C) by a known method. Above all, it is preferable to obtain by mixing and neutralizing using an aqueous medium described later. When neutralizing using an aqueous medium, the (C) may be added to the dispersion liquid in which the (X) is dispersed in the aqueous medium to neutralize the solution, or the solution of the aqueous medium (C) may be used. (X) may be mixed and neutralized, or the (X) and the (C) may be simultaneously added to and mixed in an aqueous medium to neutralize the mixture.
When the acid-modified polyolefin (X) and the base (C) are mixed using an aqueous medium, the aqueous medium used at the time of neutralization may be distilled off after neutralization.

<Aqueous dispersion>
The modifier for cellulose nanofibers of the present invention requires the (partially) neutralized product (XC) of the acid-modified polyolefin (X) and the base (C), but further contains an aqueous medium, and the above-mentioned ( Sub) An aqueous dispersion of neutralized product (XC) is preferred. The aqueous dispersion is a modified polyolefin aqueous dispersion in which the (partial) neutralized product (XC) is dispersed in an aqueous medium and the modified polyolefin which is the (partially) neutralized product is dispersed.

Examples of the aqueous medium include water, an aqueous solvent and the like. In the present application, the aqueous solvent means an organic solvent having a solubility in 100 g of water at 25 ° C. of 10 g or more.
Examples of the aqueous solvent include ketones {acetone, methyl ethyl ketone (hereinafter abbreviated as MEK), diethyl ketone and the like}, alcohols (methanol, ethanol, isopropanol and the like) and the like, and acetone, MEK and isopropanol are preferable.
Further, the aqueous solvent can be used alone or in combination of two or more.
As the aqueous medium, it is preferable to use a medium containing 70% by weight or more of water, more preferably 90% by weight or more of water, and particularly preferably water.

The aqueous dispersion can be produced by the following method.
Production method (1): Acid-modified polyolefin (X), base (C), and aqueous medium are charged, mixed, and then the aqueous medium is charged with further stirring for phase inversion emulsification, and the aqueous medium is further distilled off if necessary. To obtain an aqueous dispersion.
Production method (2): An acid-modified polyolefin (X), a base (C), and an aqueous medium are charged, and the mixed mixture and the aqueous medium are dispersed by a disperser to obtain an aqueous dispersion.
Of the above-mentioned production methods (1) and (2), the production method (1) is preferable from the viewpoint of storage stability of the aqueous dispersion.
Further, in the step of obtaining the aqueous dispersion, in addition to the acid-modified polyolefin (X) and the base (C), if necessary, a known (for example, emulsifier (F) etc. described in JP-A-2015-131889) anionic anion. A sex surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant may be used.

The weight of the (partial) neutralized product (XC) based on the weight of the aqueous dispersion is preferably 5 to 50% by weight, more preferably 10 to 45% by weight, still more preferably 15 to 40% from the viewpoint of storage stability. It is% by weight.
When the modifying agent for cellulose nanofibers of the present invention is an aqueous dispersion, the modifying agent for cellulose nanofibers of the present invention further adds an aqueous medium when used in the operation for modifying cellulose nanofibers. It may be diluted with a low concentration (for example, 0.05 to 5% by weight, etc.) before use. The modifier for cellulose nanofibers can be distributed in a high-concentration aqueous dispersion to reduce transportation costs and storage costs, and the modification treatment at a low concentration improves handleability and modification efficiency. Can be improved.

Further, the volume-based median diameter (hereinafter referred to as median particle diameter) of the (partial) neutralized product (XC) dispersed in the aqueous dispersion is preferably 0.05 to 0 from the viewpoint of storage stability and the like. It is 5 μm, more preferably 0.1 to 2.5 μm. The median particle size can be measured by a laser diffraction type particle size distribution measuring device.

<Cellulose nanofiber>
The cellulose nanofiber modified by the modifier for cellulose nanofiber of the present invention is a cellulose fine fiber having a fiber diameter of nanometer level.
The fiber diameter of the cellulose nanofibers modified by the modifier for cellulose nanofibers of the present invention is not limited, and examples thereof include cellulose fine fibers having a number average fiber diameter of 3 to 800 nm.
As the cellulose nanofibers, those obtained by refining (also referred to as defibration) the cellulose raw material by a known method can be used, and as the refining method, an aqueous dispersion of cellulose fibers is used as a refiner and a high-pressure homogenizer. , Grinder, uniaxial or multiaxial kneader, method of mechanically refining with a bead mill, etc., water suspension of chemically modified cellulose such as oxidized cellulose obtained by chemical treatment of cellulose, refiner, high pressure homogenizer, grinder, etc. Examples thereof include a method of mechanically defibrating with a uniaxial or multiaxial kneader, a bead mill or the like.

As the cellulose raw material, pulp obtained by mechanically treating and / or chemically treating plant fibers can be used, and chemical pulp such as kraft pulp, semi-chemical pulp, chemigrand pulp, chemimechanical pulp, crushed wood pulp, and refiner can be used. Examples thereof include mechanical pulp, thermomechanical pulp, chemithermomechanical pulp, and deinked waste paper pulp containing these pulps as a main component, cardboard waste paper pulp, magazine waste paper pulp and the like.

In addition to the above method, cellulose nanofibers can also be obtained by refining cellulose by the methods described in Re-Table 2009/069641A, JP2013-155445A, JP2008-308802A, and the like.
Cellulose nanofibers produced by these methods are produced by paper companies and are available on the market in the form of solid or aqueous dispersions.

The second method for producing modified cellulose nanofibers according to the present invention includes a step of mixing the above-mentioned cellulose nanofibers with the above-mentioned modifier for cellulose nanofibers.

The above-mentioned cellulose nanofibers and the above-mentioned modifier for cellulose nanofibers can be mixed by a known method, and the modifier for cellulose nanofibers to be mixed with the cellulose nanofibers is an embodiment of an aqueous dispersion. However, it may be an embodiment that does not contain a dispersion medium (for example, when the (partial) neutralized product (XC) itself of the acid-modified polyolefin (X) and the base (C) is used).

When using the reforming agent for cellulose nanofibers which is an aqueous dispersion, put the reforming agent for cellulose nanofibers in a mixing container equipped with a stirrer, add the cellulose nanofibers while stirring, and further homogenize the cellulose nanofibers. Modified cellulose nanofibers can be obtained by mixing the fiber with a modifier for cellulose nanofibers. The temperature at which the cellulose nanofibers and the modifier for cellulose nanofibers are mixed is not limited, but is preferably 80 ° C. or lower.
Further, a step of uniformly mixing the cellulose nanofibers and a modifier for cellulose nanofibers and then solid-liquid separation using a filter such as a filter press, and a solid portion obtained by the solid-liquid separation is a drum dryer or the like. The step of heating and drying may be performed using a known dryer of the above.
The heating temperature in the heat-drying step is preferably 100 to 180 ° C., and it is more preferable to perform heat-drying under reduced pressure.

When a modifier for cellulose nanofibers, which is an aqueous dispersion, is used, the ratio of cellulose nanofibers to the (partial) neutralizer (XC) contained in the modifier for cellulose nanofibers is adjusted according to the properties of the cellulose nanofibers. However, it is preferable to mix under the conditions of 10/90 to 90/10.
Further, by mixing the cellulose nanofibers with an excessive amount of the (partial) neutralized product (XC), the mixture can be used as it is with the fiber-reinforced composite material described later. When a mixture of cellulose nanofibers and a modifier for cellulose nanofibers is used as a fiber-reinforced composite material described later, the cellulose nanofibers with respect to the (partial) neutralizer (XC) contained in the modifier for cellulose nanofibers. It is preferable to mix under the condition that the ratio of is 1/99 to 99/1.

When the (partial) neutralized product (XC) itself of the acid-modified polyolefin (X) and the base (C) is used as the modifier for cellulose nanofibers in an embodiment that does not contain a dispersion medium, the (partially) neutralized product (partially) neutralized product ( Modified cellulose nanofibers can be obtained by mixing XC) with cellulose nanofibers or an aqueous dispersion of cellulose nanofibers with a known mixer.
Among them, a mixer with a stirrer for planetary motion of the (partial) neutralizer (XC) and an aqueous dispersion of cellulose nanofibers, and powder and dispersion of a stirrer-type powder mixer such as a planetary mixer. It is preferable to mix with the body using a device capable of uniformly mixing. The temperature at which the cellulose nanofibers and the modifier for cellulose nanofibers are mixed is not limited, but is preferably 80 ° C. or lower.
Further, a step of uniformly mixing the cellulose nanofibers and a modifier for cellulose nanofibers and then solid-liquid separation using a filter such as a filter press, and a solid portion obtained by the solid-liquid separation is a drum dryer or the like. The step of heating and drying may be performed using a known dryer of the above.
The heating temperature in the heat-drying step is preferably 100 to 180 ° C., and it is more preferable to perform heat-drying under reduced pressure.

The ratio of the cellulose nanofibers to the (partial) neutralized product (XC) can be adjusted according to the properties of the cellulose nanofibers and the like, but it is preferable to mix them under the condition of 10/90 to 90/10.
Further, by mixing the cellulose nanofibers with an excessive amount of the (partial) neutralized product (XC), the mixture can be used as it is with the fiber-reinforced composite material described later. When a mixture of cellulose nanofibers and a modifier for lurose nanofibers is used as a fiber-reinforced composite material described later, the ratio of cellulose nanofibers to (partially) neutralized product (XC) is 1/99 to 99 /. It is preferable to mix under the condition of 1.

Whether or not the modified cellulose nanofibers were obtained by mixing the above-mentioned cellulose nanofibers and the above-mentioned reforming agent for cellulose nanofibers was determined by measuring the infrared absorption spectrum of the mixture and using the modifier for cellulose nanofibers. It can be determined by confirming that the position of the peak derived from the carbonyl group of the (partial) neutralized product (XC) contained above has changed from that before mixing.
The (partial) neutralizer (XC) is adsorbed on the surface of the cellulose nanofibers, thereby modifying the cellulose nanofibers, but the polar groups such as hydroxyl groups present on the surface of the cellulose nanofibers and the above-mentioned The (partial) neutralizer (XC) is adsorbed by interacting with the carboxyl group of the neutralizer (XC), or forms an ester bond, and is affected by the interaction and ester bond formation (partial) neutralizer (XC). ) Is presumed to change the position of the peak derived from the carbonyl group.

The modified cellulose nanofiber according to the third invention of the present application is a modified cellulose nanofiber in which a (partial) neutralized product (XC) of an acid-modified polyolefin (X) and a base (C) is attached to the surface of the cellulose nanofiber. The above (X) contains a polyolefin (A) having a carbon-carbon double bond and an unsaturated (poly) carboxylic acid (anhydride) (B) as constituent raw materials, and the above (A) is ethylene. A modified cellulose nanofiber containing α-olefin having 3 to 8 carbon atoms as a constituent monomer and having a weight ratio [ethylene / α-olefin] of ethylene to α-olefin of 3/97 to 50/50. Is.

Cellulose nanofibers constituting the modified cellulose nanofibers of the present invention, acid-modified polyolefin (X), base (C), (partially) neutralized product (XC), polyolefin (A) having a carbon-carbon double bond, and The unsaturated (poly) carboxylic acid (anhydride) (B) is the same as that described in the above-mentioned modifier for cellulose nanofibers, and the preferred one is also the same.

The modified cellulose nanofibers can be produced by mixing the above-mentioned cellulose nanofibers with the above-mentioned modifier for cellulose nanofibers.

Whether or not it is a modified cellulose nanofiber can be confirmed by measuring the position of the peak derived from the carbonyl group of the (partially) neutralized product (XC) from the infrared absorption spectrum.

The fourth fiber-reinforced composite material of the present application is a composite material containing the modified cellulose nanofibers, and contains the modified cellulose nanofibers and a matrix resin.
As the matrix resin, a thermoplastic resin (polyolefin resin such as polypropylene resin, polyamide resin, polyester resin, polycarbonate resin, polyphenylene sulfide resin, etc.) and a thermosetting resin [epoxy resin, unsaturated polyester resin (Patent No. 3723462). , Etc.), vinyl ester resin and phenol resin (for example, those described in Japanese Patent No. 3723462), etc.], preferably a polyolefin resin, and preferably a polypropylene resin.

The fiber-reinforced composite material of the present invention contains the above-mentioned modified cellulose nanofibers and a matrix resin, but may contain an acid-modified polyolefin excessively used in the production of the modified cellulose nanofibers as a part of the matrix resin.

In the fiber-reinforced composite material of the present invention, the weight ratio of the matrix resin and the modified cellulose nanofibers (matrix resin / modified cellulose nanofibers) shall be adjusted according to the application of the fiber-reinforced composite material, the required strength, and the like. However, from the viewpoint of dispersibility of the modified cellulose nanofibers in the fiber-reinforced composite material, 10/90 to 90/10 is preferable, more preferably 20/80 to 50/50, and particularly preferably 20/ It is 80 to 40/60.
When a fiber-reinforced composite material is obtained by mixing a heat-melted matrix resin described later with modified cellulose nanofibers, it is modified by increasing the amount of modified cellulose nanofibers (increasing the concentration) to apply a stronger shearing force. The dispersibility of quality cellulose nanofibers may be better. A fiber-reinforced composite material containing a high concentration of modified cellulose nanofibers as described above is sometimes called a masterbatch, and the masterbatch is used by further melt-mixing with another thermoplastic resin.

The fiber-reinforced composite material of the present invention includes a matrix resin that has been thermally melted (preferably melting temperature: 60 to 250 ° C.) or a matrix resin diluted with a solvent (acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, ethyl acetate, etc.). It can be produced by mixing with modified cellulose nanofibers. When a solvent is used, it is preferable to distill off the solvent after mixing.
Mixing of the heat-melted matrix resin and the modified cellulose nanofibers is performed using a known kneading device such as a screw type mixer, a screw type extruder, a Nauter mixer, a double arm type kneader, a minced mixer and a roll mixer. Can be done.
The mixing of the matrix resin diluted with the solvent and the modified cellulose nanofibers can be performed using a known mixing container equipped with a stirrer.

When the matrix resin is a thermoplastic resin, the fiber-reinforced composite material of the present invention can be used for various purposes as a molded body by heat-molding and solidifying. The heat molding method is not particularly limited, and is a filament winding molding method (a method of winding a rotating mandrel while applying tension to heat molding) and a press molding method (a method of laminating and heat molding a sheet-shaped fiber-reinforced composite material). Method), autoclave method (method of pressing a sheet-shaped fiber-reinforced composite material against a mold to heat-mold), and a method of further mixing finely crushed fiber-reinforced composite material with a matrix resin and injection molding. ..

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<Manufacturing example 1>
High molecular weight polyolefin (A0-1) containing 85% propylene and 15% ethylene as constituent monomers in a reaction vessel [trade name "Vistamaxx6202", manufactured by ExxonMobil, the same applies hereinafter. ] 1000 parts by weight is charged, and the liquid phase is heated with a mantle heater while aerating nitrogen, and the melted material is heated at 380 ° C. for 50 minutes while stirring to obtain a high molecular weight polyolefin (A01-1). Thermal reduction was performed to obtain a polyolefin (A-1) having a carbon-carbon double bond. The Mn of the polyolefin (A-1) is 3,900, the number of carbon-carbon double bonds in the molecular terminal and the molecular chain per 1,000 carbons is 7.4, and the isotacticity is 17%. Met.

<Production Examples 2 to 10, Comparative Production Examples 1 to 2>
The same procedure as in Production Example 1 was carried out except that the type of the high molecular weight polyolefin (A0) used and the heat-decomposing conditions were according to Table 1, and the polyolefins (A-2) to (A) having a carbon-carbon double bond were carried out. -10) and (ratio A-1) to (ratio A-2) were obtained. Mn of each polyolefin (A) having a carbon-carbon double bond, the number of carbon-carbon double bonds per 1,000 carbons, the number of carbon-carbon double bonds in the molecular chain, and the weight ratio of ethylene to α-olefin [ethylene / α-olefin] and isotacticity are shown in Table 1.

<Manufacturing example 11>
100 parts by weight of polyolefin (A-1) having a carbon-carbon double bond and 5 parts by weight of maleic anhydride (B-1) are charged in a reaction vessel, and after nitrogen substitution, the temperature is raised to 180 ° C. under nitrogen aeration. It was uniformly dissolved. A solution prepared by dissolving 2 parts by weight of a radical initiator [Dikumil peroxide, trade name "Parkmill D", manufactured by NOF CORPORATION] (f-1) in 5 parts by weight of xylene was added dropwise over 5 minutes. , Stirring was continued for 1 hour under reflux with xylene. Then, unreacted maleic anhydride was distilled off under reduced pressure (1.5 kPa, the same applies hereinafter) to obtain an acid-modified polyolefin (X-1).
The acid value of the acid-modified polyolefin (X-1) was 26, the Mn was 4,500, and the isotacticity was 14%.

<Production Examples 12 to 23, Comparative Production Examples 3 to 4>
Except for the types of polyolefin (A) having a carbon-carbon double bond, unsaturated (poly) carboxylic acid (anhydride) (B), and radical initiator (f), and the amount used according to Table 2.
The same procedure as in Production Example 11 was carried out to obtain acid-modified polyolefins (X-2) to (X-13) and (ratio X-1) to (ratio X-2).

Table 2 shows the properties of the acid-modified polyolefin (X).

<Manufacturing example 24>
100 parts by weight of coniferous bleached kraft pulp fiber (refiner-treated, solid content 25% by weight) was sufficiently stirred and mixed with 3300 parts by weight of ion-exchanged water, and then mechanically defibrated using a bead mill. Subsequently, dehydration was performed using a filter press to obtain hydrocellulose nanofibers having a solid content of 10% by weight.
100 parts by weight of the obtained water-containing cellulose nanofibers was added to 900 parts by weight of ion-exchanged water, and the mixture was stirred with a homomixer at 5000 rpm for 30 minutes to obtain a cellulose nanofiber aqueous dispersion (CNFW-1). The solid content concentration of the dispersion was 1.0% by weight.

<Manufacturing example 25>
100 parts by weight of bleached kraft pulp fiber (refiner treated, solid content 25% by weight) of coniferous tree was sufficiently stirred and mixed with 9900 parts by weight of ion-exchanged water, and then 1.25% by weight with respect to 100 parts by weight of pulp. , 2,6,6-Tetramethylpiperidinooxy radical (ALDRICH reagent), 12.5% by weight of sodium bromide, and 28.4% by weight of sodium hypochlorite were added in this order.
Subsequently, using an automatic potential difference titrator, 0.5 M sodium hydroxide was added dropwise to maintain the pH at 10.5, and an oxidation reaction was carried out to produce a carboxyl group-containing cellulose fiber.
After the oxidation reaction was continued for 120 minutes, the dropping was stopped, the carboxyl group-containing cellulose fibers were thoroughly washed with ion-exchanged water, and then dehydration treatment was performed. 100 parts by weight of dehydrated carboxyl group-containing cellulose fiber was dispersed in 9900 parts by weight of ion-exchanged water, and the fiber was refined twice with a high-pressure homogenizer (HJP-25005, manufactured by Sugino Machine Co., Ltd.) at a discharge pressure of 245 MPa. This was performed to obtain a cellulose nanofiber dispersion liquid (CNFW-2).
The solid content concentration of the dispersion was 1.0% by weight, and the carboxyl group content of the cellulose nanofibers was 1.2 mmol / g.

<Manufacturing example 26>
Production Example 23 except that 2,2,6,6-tetramethylpiperidinooxy radical is 0.94% by weight, sodium bromide is 0.94% by weight, and sodium hypochlorite is 21.3% by weight. In the same manner as above, a cellulose nanofiber dispersion liquid (CNFW-3) was obtained.
The solid content concentration of the dispersion was 1.0% by weight, and the carboxyl group content of the cellulose nanofibers was 0.9 mmol / g.

<Example 1>
Acid-modified polyolefin (X-1) 100 parts by weight, triethylamine (C-1) [manufactured by Tokyo Chemical Industry Co., Ltd.] 4.5 parts by weight, tetrahydrofuran 80 in a reaction vessel equipped with a stirrer, heating / cooling device and thermometer. A portion by weight was charged and heated to 60 ° C. with stirring to uniformly dissolve (X-1) in tetrahydrofuran. Further, 233 parts by weight of water was added little by little over 5 hours while stirring, and phase inversion emulsification was performed. After cooling to room temperature, tetrahydrofuran is removed under reduced pressure, water is added so that the solid content becomes 30.0% by weight, and the aqueous dispersion containing the (partial) neutralizer (XC-1) is used. A modifier for cellulose nanofibers (D-1) was obtained.

The median particle size of the (partial) neutralizer (XC-1) contained in the cellulose nanofiber modifier (D-1) and the cellulose nanofiber modifier (D-1) evaluated by the following method. Storage stability at 40 ° C [storage stability (40 ° C)] and storage stability of the cellulose nanofiber modifier (D-1) evaluated by the following method at 5 ° C [storage stability (5 ° C). )] And are shown in Table 3.

<Median particle size>
The modifier (D-1) for cellulose nanofibers obtained in Example 1 was measured using a laser diffraction type particle size distribution measuring device "LA-750" [manufactured by HORIBA, Ltd.]. The median particle size obtained here is taken as the median particle size before storage in the following storage stability.

<Storage stability>
<1: Storage stability at 40 ° C (40 ° C)>
30 g of a modifier for cellulose nanofibers (D-1) was placed in a screw bottle [50 mL (body diameter 35 mm x height 78 mm)] and stored at 40 ° C. for 14 days, and the median particles after storage at 40 ° C. The diameter was measured.
From the measurement results of the median particle size (μm) before and after storage, (storage stability at 40 ° C.) was obtained by the following formula, evaluated according to the following evaluation criteria, and the results are shown in Table 3.
(Storage stability at 40 ° C) (%) = (Median particle size after storage at 40 ° C) x 100 / (Median particle size before storage)

<Evaluation criteria>
☆: Less than 105% ◎: 105% or more, less than 110% ○: 110% or more, less than 115% △: 115% or more, less than 120% ×: 120% or more

<2: Storage stability at 5 ° C (5 ° C)>
30 g of a modifier for cellulose nanofibers (D-1) was placed in a screw tube bottle [50 mL (body diameter 35 mm x height 78 mm)] and stored at 5 ° C. for 14 days, and the median particles after storage at 5 ° C. The diameter was measured.
From the measurement results of the median diameter (μm) before and after storage, (storage stability at 5 ° C) was obtained by the following formula, evaluated according to the following evaluation criteria, and the results are shown in Table 3.
(Storage stability at 5 ° C) (%) = (Median particle size after storage at 5 ° C) x 100 / (Median particle size before storage)

<Evaluation criteria>
☆: Less than 105% ◎: 105% or more, less than 110% ○: 110% or more, less than 115% △: 115% or more, less than 120% ×: 120% or more

<Examples 2 to 16, Comparative Examples 1 to 2>
<< Modifier for cellulose nanofibers, which is an aqueous dispersion >>
The (partial) neutralized product (partially) in the same manner as in Example 1 except that the acid-modified polyolefin (X), the base (C), and the type and amount of the aqueous medium were according to the raw material composition (part) in Table 3. Modifiers (D-2) to (D-16) for cellulose nanofibers, which are aqueous dispersions containing XC), and aqueous dispersions (ratio D-1) to (ratio D-2) for comparison are obtained. rice field. Table 3 shows the results of the median particle size and storage stability measured and evaluated in the same manner as the modifier for cellulose nanofiber (D-1) obtained in Example 1.

<Examples 17 to 32, Comparative Example 4>
<< Modifier for cellulose nanofibers obtained by dehydrating water dispersion >>
The aqueous dispersions (D-1) to (D-16) and (ratio D-2) obtained in Examples 1 to 16 and Comparative Example 2 were provided with a depressurizing device, a stirring device, a heating / cooling device, and a thermometer. Put it in a closed container, gradually reduce the pressure inside the container (to 20 kPa or less) while stirring, gradually heat to 120 ° C. to distill off the dispersion medium in the aqueous dispersion, and (partially) neutralize the neutralized product (partially). Modified agents (CX-1) to (CX-16) for cellulose nanofibers composed of XC) and a (partial) neutralized product (ratio CX-2) for comparison were obtained.

<Comparative Example 3>
The aqueous dispersion (ratio D-1) obtained in Comparative Example 1 was put into a closed container equipped with a decompression device, a stirrer, a heating / cooling device and a thermometer, and the inside of the container was gradually depressurized (20 kPa or less) while stirring. (Up to), gradually heat to 160 ° C. to distill off the dispersion medium in the aqueous dispersion, and heat-dry under the conditions of to obtain a (partial) neutralizer (ratio CX-1) for comparison. rice field.

<Examples 33 to 52, Comparative Examples 5 to 6>
<< Manufacture of modified cellulose nanofibers and fiber-reinforced composite material using a modifier for cellulose nanofibers obtained by dehydrating an aqueous dispersion >>
Modified agents for cellulose nanofibers (CX-1) to (CX-16) obtained in Examples 17 to 32, and comparative (partial) neutralized products (ratio CX-) obtained in Comparative Examples 3 to 4. 1)-(Ratio CX-2) and the cellulose nanofiber dispersions (CNFW-1)-(CNFW-3) obtained in Production Examples 24-26 were mixed in the combination shown in Table 4-1. Fiber-reinforced composite materials (MS-1) to (MS-20) and (ratio MS-1) to (ratio MS-2) containing modified cellulose nanofibers at a high concentration by producing modified cellulose nanofibers. Got each.
The materials shown in Table 4 were mixed by the following methods.

<Mixing method of materials shown in Table 4>
Depressurizing airtight container equipped with a stirrer, heating / cooling device and thermometer for cellulose nanofiber modifiers (CX-1) to (CX-16) or (ratio CX-1) to (ratio CX-2) 50 parts by weight was added, and the mixture was heated to 90 ° C. for Examples 33 to 52 and Comparative Example 5 and to 160 ° C. for Comparative Example 6 while stirring.
Subsequently, 5000 parts of the cellulose nanofiber dispersion (CNFW) was gradually added to each container under stirring over 3 hours, stirred and mixed until uniform, and then with respect to Examples 33 to 52 and Comparative Example 6. The modified cellulose nanofibers are produced by heating to 150 ° C. and 180 ° C. for Comparative Example 5 and gradually reducing the pressure to 1.5 kPa or less for dehydration, and containing the modified cellulose nanofibers at a high concentration. A fiber-reinforced composite material (a fiber-reinforced composite material containing modified cellulose nanofibers and an excess (partially) neutralized product (CX)) was obtained.

<< CNF reinforced polypropylene resin >>
95 parts by weight of fiber-reinforced composite materials (MS-1) to (MS-20) or (ratio MS-1) to (ratio MS-2) shown in Table 4 and 95 parts by weight of SunAllomer PL920A "[Polypropylene, SunAllomer Made by Sanyo Kasei Kogyo Co., Ltd.] and 5 parts by weight of "Umex 1001" [anhydrous maleic acid-modified polypropylene, acid value 26, manufactured by Sanyo Kasei Kogyo Co., Ltd.] are melt-kneaded at 220 ° C. using a twin-screw extruder. To obtain a CNF-reinforced polypropylene resin containing each of the fiber-reinforced composite materials (MS-1) to (MS-20) or (ratio MS-1) to (ratio MS-2).
The obtained CNF-reinforced polypropylene resin contains 5% by weight of cellulose nanofibers.

CNF reinforced containing the fiber-reinforced composite materials (MS-1) to (MS-20) or (ratio MS-1) to (ratio MS-2) obtained in Examples 33 to 52 and Comparative Examples 5 to 6, respectively. The tensile strength, tensile elastic modulus, and dispersibility of cellulose nanofibers (described as CNF dispersibility) were evaluated for the polypropylene resin by the following methods, and the results are shown in Table 4.

<Tensile strength>
Each CNF-reinforced polypropylene resin was molded using an injection molding machine [trade name "PS40E5ASE", Nissei Resin Industry Co., Ltd.] at a cylinder temperature of 200 ° C. and a mold temperature of 60 ° C., and measured in accordance with JIS K7161.
<Evaluation criteria>
⊚: 50 MPa or more ○: 45 MPa or more and less than 50 MPa Δ: 40 MPa or more and less than 45 MPa ×: less than 40 MPa

<Tension modulus>
Each CNF-reinforced polypropylene resin was molded using an injection molding machine [trade name "PS40E5ASE", Nissei Resin Industry Co., Ltd.] at a cylinder temperature of 200 ° C. and a mold temperature of 60 ° C., and measured in accordance with JIS K7161.
<Evaluation criteria>
⊚: 1800 MPa or more ○: 1700 MPa or more and less than 1800 MPa Δ: 1600 MPa or more and less than 1700 MPa ×: less than 1600 MPa

<Dispersibility of CNF>
The cross section of the test piece after the evaluation of the above <tensile strength> was visually evaluated according to the following <evaluation criteria>.
<Evaluation criteria>
◎: Good ○: Almost no uneven distribution or dropout of cellulose nanofibers △: Uneven distribution or dropout of cellulose nanofibers can be confirmed ×: Uneven distribution or dropout of cellulose nanofibers is conspicuous

<Examples 47 to 64, Comparative Examples 5 to 6>
<< Manufacture of modified cellulose nanofibers and fiber-reinforced composite material using a modifier for cellulose nanofibers, which is an aqueous dispersion >>
Modified agents (D-1) to (D-14) for cellulose nanofibers, which are aqueous dispersions of the (partial) neutralized product (XC) obtained in Examples 1 to 14, obtained in Comparative Examples 1 and 2. The comparative aqueous dispersions (ratio D-1) to (ratio D-2) and the cellulose nanofiber dispersions (CNFW-1) to (CNFW-3) obtained in Production Examples 22 to 24 are shown in the table. The modified cellulose nanofibers are produced by mixing in the combination described in 5, and the fiber-reinforced composite materials (MS-19) to (MS-36) and (specific MS-) containing the modified cellulose nanofibers at a high concentration are produced. 3)-(Ratio MS-4) were obtained. The materials shown in Table 4 were mixed by the following methods.

<Mixing method of materials shown in Table 5>
Modified agents (D-1) to (D-16) for cellulose nanofibers, which are aqueous dispersions, in a depressurized closed container (simple autoclave) equipped with a stirrer, a heating / cooling device, a dropping device, and a thermometer, or a comparison. 50 parts by weight of the comparative aqueous dispersions (ratio D-1) to (ratio D-2) obtained in Examples 1 and 2 were added, and Examples 47 to 64 and Comparative Example 6 were stirred while stirring in a closed container. Is heated to 90 ° C., and Comparative Example 5 is heated to 160 ° C. Subsequently, 5000 parts of the cellulose nanofiber dispersion (CNFW) was gradually dropped from the dropping device over 3 hours while maintaining the hermeticity, and the pressure was gradually reduced to 1.5 kPa or less, and the temperature was simultaneously applied. Modified cellulose nanofibers are produced by gradually raising the temperature to 150 ° C. for Examples 47 to 64 and Comparative Example 6 and to 180 ° C. for Comparative Example 5 to dehydrate the modified cellulose nanofibers. A fiber-reinforced composite material containing a high concentration of nanofibers (a fiber-reinforced composite material containing modified cellulose nanofibers and an excess (partially) neutralized product (CX)) was obtained.

<< CNF reinforced polypropylene resin >>
95 parts by weight of fiber-reinforced composite materials (MS-19) to (MS-38) or (ratio MS-3) to (ratio MS-4) shown in Table 5 and 95 parts by weight of SunAllomer PL920A "[Polypropylene, SunAllomer Made by Sanyo Kasei Kogyo Co., Ltd.] and 5 parts by weight of "Umex 1001" [anhydrous maleic acid-modified polypropylene, acid value 26, manufactured by Sanyo Kasei Kogyo Co., Ltd.] are melt-kneaded at 220 ° C. using a twin-screw extruder. To obtain a CNF-reinforced polypropylene resin containing each of the fiber-reinforced composite materials (MS-19) to (MS-38) or (ratio MS-3) to (ratio MS-4).
The obtained CNF-reinforced polypropylene resin contains cellulose nanofibers in an amount of 5% by weight.

CNF reinforced containing the fiber-reinforced composite materials (MS-19) to (MS-38) or (ratio MS-3) to (ratio MS-4) obtained in Examples 53 to 72 and Comparative Examples 7 to 8, respectively. For polypropylene resin, tensile strength, tensile modulus and dispersion of cellulose nanofibers were carried out by the same method as that evaluated for the fiber-reinforced composite materials (MS-1) to (MS-20) obtained in Examples 33 to 52 above. The sex (described as CNF dispersibility) was evaluated and the results are shown in Table 5.

From the results in Tables 3 to 5, the modifier for cellulose nanofibers of the present invention, which is an aqueous dispersion of a (partially) neutralized product (XC) of an acid-modified polyolefin (X) and a base (C), has storage stability. The modified cellulose nanofibers modified using the modifier for cellulose nanofibers of the present invention, which are excellent in the above and contain a (partially) neutralized product (XC) of an acid-modified polyolefin (X) and a base (C), are fibers. It can be seen that the fiber-reinforced composite material (CNF-reinforced polypropylene resin) obtained is excellent in dispersibility in the reinforced composite material and has excellent mechanical strength.

The modifier for cellulose nanofibers of the present invention can improve the dispersibility of cellulose nanofibers in a thermoplastic resin and gives excellent mechanical strength to a fiber-reinforced composite material using cellulose nanofibers. It is useful.

Claims (11)

It contains a (partially) neutralized product (XC) of an acid-modified polyolefin (X) and a monovalent base (C), wherein the (X) is unsaturated with the polyolefin (A) having a carbon-carbon double bond (X). Poly) Carboxylic acid (anhydrous) (B) is contained as a constituent raw material, and (A) contains ethylene and an α-olefin having 3 to 8 carbon atoms as a constituent monomer, and ethylene and α-olefin. A modifier for cellulose nanofibers having a weight ratio [ethylene / α-olefin] of 3/97 to 50/50. The modifier for cellulose nanofibers according to claim 1, which comprises an aqueous medium and is an aqueous dispersion of the (partially) neutralized product (XC). The modifier for cellulose nanofibers according to claim 1 or 2, wherein the number of carbon-carbon double bonds per 1,000 carbon atoms of the polyolefin (A) is 0.5 to 20. The modifier for cellulose nanofibers according to any one of claims 1 to 3, wherein the acid value of the acid-modified polyolefin (X) is 1 to 100 mgKOH / g. The modifier for cellulose nanofibers according to any one of claims 1 to 4, wherein the acid-modified polyolefin (X) has a number average molecular weight (Mn) of 1,000 to 60,000. The modifier for cellulose nanofibers according to any one of claims 1 to 5, wherein the isotacticity of the α-olefin unit chain portion of the acid-modified polyolefin (X) is 1 to 50%. The cellulose according to any one of claims 1 to 6, wherein the monovalent base (C) is a trialkylamine, and the carbon atoms of the three alkyl groups of the trialkylamine are independently 1 to 4, respectively. Modifier for nanofibers. The item according to any one of claims 1 to 7, wherein the ratio (γ) of the number of moles of the monovalent base (C) based on the number of moles of the carboxyl group derived from the acid-modified polyolefin (X) is 10 to 100%. The modifier for cellulose nanofibers described. A method for producing modified cellulose nanofibers, which comprises a step of mixing the cellulose nanofibers with the modifying agent for cellulose nanofibers according to any one of claims 1 to 8. A modified cellulose nanofiber in which a (partial) neutralized product (XC) of an acid-modified polyolefin (X) and a base (C) is attached to the surface of the cellulose nanofiber.
The (X) contains a polyolefin (A) having a carbon-carbon double bond and an unsaturated (poly) carboxylic acid (anhydrous) (B) as constituent raw materials, and the (A) contains ethylene and 3 carbon atoms. A modified cellulose nanofiber containing up to 8 α-olefins as a constituent monomer and having a weight ratio of ethylene to α-olefin [ethylene / α-olefin] of 3/97 to 50/50. A fiber-reinforced composite material containing the modified cellulose nanofibers according to claim 10.