WO2022118888A1

WO2022118888A1 - Resin composition, method for producing resin composition, and resin

Info

Publication number: WO2022118888A1
Application number: PCT/JP2021/044105
Authority: WO
Inventors: 勇悟宮田; 彰宏後藤; じゆん ▲高▼田; 駿中野; 速人 ▲吉▼川
Original assignee: 東亞合成株式会社
Priority date: 2020-12-03
Filing date: 2021-12-01
Publication date: 2022-06-09
Also published as: JPWO2022118888A1

Abstract

The present invention provides a resin composition which comprises nanocellulose and a thermoplastic resin, the nanocellulose and the thermoplastic resin having formed a fibrous composite. The present invention provides a method for producing a resin composition comprising nanocellulose and a thermoplastic resin, the method comprising: step A in which a solid matter at least containing nanocellulose is sedimented from an aqueous mixture at least containing the nanocellulose, the solid matter is separated from the liquid phase, and an organic solvent is added to the solid matter to prepare a mixture I of the nanocellulose, the thermoplastic resin, and the organic solvent; and step B in which some or all of the organic solvent is removed from the mixture I substantially in the absence of water.

Description

Resin composition, method for producing resin composition, and resin

The present invention relates to a resin composition, a method for producing a resin composition, and a resin.

Conventionally, carbon fiber, glass fiber, etc. have been used as the reinforcing material for the thermoplastic resin. In recent years, research on the use of plant fiber as a reinforcing material in addition to reinforcing materials such as carbon fiber and glass fiber has been promoted. Plant fibers are not artificially synthesized, but are used by loosening plant-derived fibers. Since the plant fiber does not remain as ash during combustion, there are no problems such as ash treatment in the incinerator and landfill treatment. For this reason, in recent years, research on the use of plant fibers as a reinforcing material has been promoted, and in particular, the use of cellulose nanofibers obtained by defibrating plant fibers to the nano level has been actively studied.

Since cellulose nanofibers have a large number of hydrophilic functional groups, they have a low affinity with the resin, and there is a problem that a sufficient reinforcing effect cannot be obtained even if they are kneaded with the resin as they are.
In order to solve the above problems, for example, Patent Document 1 proposes a method for producing a composite, which comprises copolymerizing an ethylenically unsaturated monomer in a cellulose nanofiber dispersion. According to this production method, a composite of cellulose nanofibers and a resin (a copolymer of ethylene unsaturated monomer) in which cellulose nanofibers are uniformly dispersed in rubber or a resin and exhibits high strength is produced. It is said that it can be done. Further, Patent Document 2 proposes a composite resin composition obtained by polymerizing the polymerizable compound in a dispersion liquid in which a polymerizable compound and cellulose nanofibers are dispersed in a solvent. This composite resin composition is said to have high dispersibility in the resin of cellulose nanofibers.

Further, Patent Document 3 discloses an additive for modifying a resin, which is suitably used for producing a cellulose nanofiber composite formation in which cellulose nanofibers are highly dispersed in a resin. This resin modification additive is kneaded with a thermoplastic resin or the like to form a cellulose nanofiber composite formation. That is, the resin modification additive of Patent Document 3 is used as a masterbatch in combination with a resin.

Further, Patent Document 4 contains cellulose nanofibers reacted with an amine or a quaternary ammonium salt compound and a polymer of an ethylenically unsaturated monomer as a resin modifier having an excellent resin modifying effect. , Resin modifiers are disclosed.

As a method for producing a resin composition containing cellulose nanofibers and a thermoplastic resin, for example, using a single-screw or twin-screw extruder, the thermoplastic resin and the cellulose nanofibers, a surface modifier and a protonic organic solvent are used. A method of melt-kneading a mixture, extruding it, and solidifying it to obtain a pellet-shaped molded product is known (see Patent Document 5). Further, in Patent Document 5, (A) 100 parts by mass of a thermoplastic resin, (B) 1 to 200 parts by mass of cellulose nanofibers having an average fiber diameter of 1000 nm or less, and (C) a surface modifier of 0. A resin composition containing 1 to 200 parts by mass and (D) 0.1 to 10000 mass ppm of an aprotonic organic solvent having a boiling point of 100 ° C. or higher is disclosed. This resin composition is said to be excellent in wear resistance and vibration fatigue characteristics in practical use while imparting sufficient mechanical properties and thermal properties to the resin molded body.

Japanese Unexamined Patent Publication No. 2016-155897 Japanese Unexamined Patent Publication No. 2014-105217 Japanese Unexamined Patent Publication No. 2013-014741 International Publication No. 2020/184177 Japanese Unexamined Patent Publication No. 2020-007492

As described above, cellulose nanofibers function as a reinforcing material for resins, but resins containing cellulose nanofibers are required to have excellent strength against various mechanical actions. The resin containing the cellulose nanofibers is required to have, for example, impact resistance and bending strength.

In Patent Documents 1 and 2, for the purpose of increasing the dispersibility of cellulose nanofibers in a resin and obtaining strength, a polymerizable compound is polymerized in a dispersion liquid of cellulose nanofibers to obtain cellulose nanofibers and a resin. It is disclosed to obtain a complex. However, the use of the complex obtained in Patent Documents 1 and 2 as a masterbatch is not disclosed in the first place, and the obtained complex is not sufficient in impact resistance and bending strength.

The resin modification additive of Patent Document 3 is suitably used for producing a cellulose nanofiber composite formation in which cellulose nanofibers are highly dispersed in the resin, and it is said that a reinforced resin can be obtained. It is required to further improve the property and the strength against bending. The resin modifier of Patent Document 4 is excellent in the resin modifying effect, but the impact resistance and the strength against bending are not described, and it is required to further improve these characteristics. The resin composition of Patent Document 5 is said to give sufficient mechanical properties to a resin molded product, but is required to further improve impact resistance and bending strength.

Therefore, it is an object of the present invention to provide a resin composition capable of obtaining a resin having improved bending strength while having impact resistance.

As a result of diligent studies by the present inventors, a resin composition containing nanocellulose and a thermoplastic resin in which the nanocellulose and the thermoplastic resin form a predetermined form has impact resistance and bending strength. We have found that we can provide an improved resin, and have completed the present invention.
Further, as a result of diligent studies, the present inventors have found that a fibrous composite of nanocellulose and a thermoplastic resin having a structure in which a thermoplastic resin is coated with nanocellulose can be produced by a predetermined production method. The present invention has been completed.

That is, the present invention is as follows.
[1]
Contains nanocellulose and thermoplastics
The nanocellulose and the thermoplastic resin form a fibrous complex.
Resin composition.
[2]
The amount of carboxy group of the nanocellulose is 0.1 mmol / g or more and 3.0 mmol / g or less.
The resin composition according to [1].
[3]
The content of the nanocellulose is 50% by mass or more with respect to the total amount of the resin composition.
The resin composition according to [1] or [2].
[4]
The thermoplastic resin contains at least one monomer unit selected from (meth) acrylic monomer, (meth) acrylamide-based monomer, styrene-based monomer, maleimide-based monomer, and nitrile-based monomer as a constituent unit.
The resin composition according to any one of [1] to [3].
[5]
The thermoplastic resin has a functional group capable of forming a chemical bond with the nanocellulose.
The resin composition according to any one of [1] to [4].
[6]
The functional group is a base or cation containing a nitrogen atom.
The resin composition according to [5].
[7]
The thermoplastic resin is a polymer having a hydrophilic portion and a hydrophobic portion.
The resin composition according to any one of [1] to [6].
[8]
The thermoplastic resin is a block copolymer having a hydrophilic segment and a hydrophobic segment.
The resin composition according to any one of [1] to [7].

[9]
A method for producing a resin composition containing nanocellulose and a thermoplastic resin.
After precipitating at least the solid content containing nanocellulose from the aqueous mixture containing at least nanocellulose and separating the solid content from the liquid phase, an organic solvent is added to the solid content, and the nanocellulose and the thermoplastic resin are added. Step A to prepare the mixture I of and the organic solvent, and
A step B of removing some or all of the organic solvent from the mixture I in the absence of substantially the presence of water.
Production method.
[10]
The organic solvent is an organic solvent that dissolves and / or swells the thermoplastic resin.
The manufacturing method according to [9].
[11]
The organic solvent contains at least one selected from an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, and a nitrile solvent.
The production method according to [9] or [10].
[12]
The step A is
A step of precipitating nanocellulose by adding a precipitating agent to the aqueous dispersion of nanocellulose and separating it from the liquid phase, and
The step of adding a thermoplastic resin and an organic solvent to the separated nanocellulose to obtain the mixture I is included.
The production method according to any one of [9] to [11].
[13]
The step A is
A step of precipitating a mixture II of nanocellulose and a thermoplastic resin by adding a precipitating agent to an aqueous mixture of an aqueous dispersion of nanocellulose and a thermoplastic resin, and separating the mixture from the liquid phase.
The step of adding an organic solvent to the mixture II of the separated nanocellulose and the thermoplastic resin to obtain the mixture I is included.
The production method according to any one of [9] to [11].
[14]
The precipitating agent is an inorganic salt.
The production method according to [12] or [13].
[15]
The precipitating agent is an organic alkali or cation containing a nitrogen atom in the molecule.
The production method according to [12] or [13].
[16]
The step A is
A step of mixing an aqueous dispersion of nanocellulose and a thermoplastic resin, reacting the nanocellulose with the thermoplastic resin to precipitate, and separating the mixture III of the nanocellulose and the thermoplastic resin from the liquid phase.
The step of adding an organic solvent to the mixture III of the separated nanocellulose and the thermoplastic resin to obtain the mixture I is included.
The production method according to any one of [9] to [11].
[17]
The separation step is continuously performed.
The production method according to any one of [12] to [16].
[18]
A method for producing a resin composition containing nanocellulose and a thermoplastic resin.
Step A to prepare a mixture I of nanocellulose, a thermoplastic resin, and an organic solvent, and
Including step B of removing some or all of the organic solvent from the mixture I in the absence of substantially the presence of water.
The step A is
A step of adding an organic alkali or cation containing a nitrogen atom in the molecule to the aqueous dispersion of nanocellulose and further adding a thermoplastic resin and an organic solvent to separate it from the aqueous phase to obtain the mixture I, or
Production including a step of adding a thermoplastic resin and an organic solvent to an aqueous dispersion of nanocellulose, and further adding an organic alkali or cation containing a nitrogen atom in the molecule to separate it from the aqueous phase to obtain the mixture I. Method.
[19]
The organic solvent is an organic solvent that dissolves and / or swells the thermoplastic resin.
The manufacturing method according to [18].
[20]
The organic solvent contains at least one selected from an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, and a nitrile solvent.
The production method according to [18] or [19].
[21]
A resin containing the resin composition according to any one of [1] to [8].
[22]
A melt containing the resin composition according to any one of [1] to [8] and the resin.
The resin according to [21].
[23]
Pellet-like,
The resin according to [21] or [22].
[24]
It is a method for manufacturing pellet-shaped resin.
A step of blending the resin composition according to any one of [1] to [8] and a resin, if necessary, and melt-kneading them, and
A manufacturing method comprising a step of pelletizing after the melt kneading.

According to the resin composition of the present invention, it is possible to obtain a resin having improved bending strength while having impact resistance. Further, according to the present invention, a fibrous composite of nanocellulose and a thermoplastic resin having a structure in which a thermoplastic resin is coated with nanocellulose can be produced, and a method for producing a resin composition containing the composite can be produced. Can be provided.

It is a figure which shows the SEM image obtained by the electron microscope observation of the resin composition of Example 1. FIG. It is a figure which shows the SEM image obtained by the electron microscope observation of the resin composition of the comparative example 1. FIG.

Hereinafter, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist.

[Resin composition]
The resin composition of the present invention contains nanocellulose and a thermoplastic resin. Further, the nanocellulose and the thermoplastic resin contained in the resin composition of the present invention form a fibrous complex.
The fibrous composite in the present invention is a composite in which the constituent nanocellulose and the thermoplastic resin are shaped like fibers. By coating nanocellulose, which has a fibrous shape, with a thermoplastic resin, a fibrous composite can be formed. Therefore, it is preferable that the thermoplastic resin in the fibrous complex is in a mode of coating nanocellulose.
It can be confirmed by observing the resin composition with a microscope that the resin composition of the present invention contains a fibrous complex. For example, it can be confirmed by observing at a magnification of 10,000 to 100,000 using an electron microscope. Specifically, it can be confirmed by the method described in Examples that the resin composition of the present invention contains a fibrous complex.
The resin composition of the present invention obtains, for example, a mixture of nanocellulose, a thermoplastic resin and an organic solvent, and removes a part or all of the organic solvent from the obtained mixture in the substantially absence of water. It can be manufactured by the method. Further, the resin composition of the present invention can be produced by the method for producing a resin composition described later.

The resin composition of the present invention may be used as a resin by pelletizing or molding as it is.
Further, the resin composition of the present invention may be used by mixing the resin composition with the target resin to be blended (hereinafter, also referred to as a raw material resin). In this case, the resin composition of the present invention is also referred to as a resin modifying composition or a resin modifying agent. That is, the resin composition of the present invention includes both the embodiment of using the resin as it is and the embodiment of the composition for modifying the resin.

In the resin composition of the present invention, the nanocellulose forms a fibrous form with the thermoplastic resin, so that the nanocellulose is uniformly dispersed in the resin composition. This is because each cellulose fiber is coated with the thermoplastic resin, so that the same amount of the thermoplastic resin is present between the respective nanocelluloses and the nanocelluloses are uniformly dispersed in the composition. To do. Such a highly dispersible resin composition has excellent dispersibility of nanocellulose in the obtained resin, and the ability to modify the resin is enhanced, so that the resin has improved bending strength while having impact resistance. Is considered to be possible. The mechanism of action in which impact resistance and bending strength appear is not limited to the above-mentioned mechanism.

The fibrous composite in the present invention is an index in which nanocellulose is uniformly dispersed in the resin composition, but the dispersibility of nanocellulose in the resin composition is also characterized by impact resistance. .. That is, whether or not it is a fibrous complex can also be determined by having a predetermined impact resistance. Specifically, the resin composition of the present invention preferably has an impact resistance of 2.0 kJ / m ² or more as measured under the following <conditions>. One aspect of the present invention is a resin composition containing nanocellulose and a thermoplastic resin having an impact resistance of 2.0 kJ / m ² or more as measured by the following <conditions>. The impact resistance is more preferably 3.0 kJ / m ² or more. The upper limit of the impact resistance is not particularly limited, but may be 100 kJ / m ² or less, or 50 kJ / m ² or less.
<Conditions>
(Preparation of test piece)
The resin composition of the present invention is added to the ABS resin in an amount of 1 to 5% by mass (in terms of nanocellulose), and the mixture is heated and kneaded using a plast mill. The kneading temperature is 25 ° C., and the kneading is gradually increased so that the final kneading temperature is 160 ° C. and the kneading time is 45 minutes in total. Then, using a pressurizer and a die, pressurize at 160 ° C. and 10 MPa for 5 minutes to form a flat plate of the kneaded product. Using the obtained flat plate-shaped kneaded product, a strip-shaped test piece having a width of 10 mm and a length of 70 mm (thickness of 3 mm) is produced.
(Measurement of impact resistance)
The Charpy impact test (notch tip radius: rN = 0.25 mm) specified in JIS K 711-1: 2012 is performed using the test piece, and the impact strength (kJ / m ² ) is measured.

The above <conditions> are specifically as described in the examples.
When the impact resistance is 2.0 kJ / m ² or more, preferably 3.0 kJ / m ² or more, it becomes an index that nanocellulose is uniformly dispersed in the resin composition, and the resin of the present invention is used. In the composition, the nanocellulose and the thermoplastic resin tend to form a fibrous composite.

The content of nanocellulose in the resin composition of the present invention may be usually 10% by mass or more with respect to the total amount of the resin composition.
The resin composition of the present invention may be used by blending it with a resin, but in this case, if the proportion of the thermoplastic resin contained in the resin composition becomes high, the performance of the target resin to be blended with the thermoplastic resin, etc. May affect. Therefore, from the viewpoint of suppressing the influence on the performance when the resin composition is blended with the resin, the content of nanocellulose is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably. It is 70% by mass or more. The upper limit of the content of nanocellulose is usually less than 100% by mass, preferably 95% by mass or less, and preferably 90% by mass or less.

<Nanocellulose>
The nanocellulose in the present invention is a general term for finely divided cellulose, and includes fine cellulose fibers, cellulose nanocrystals, and the like, and also includes modified products thereof (details of the modified products will be described later). Fine cellulose fibers are also referred to as cellulose nanofibers (also referred to as CNF). Further, in the present specification, "miniaturization" is also referred to as nanonization.
As the nanocellulose in the present invention, commercially available nanocellulose can be used, or one obtained by preparing from a cellulosic raw material such as coniferous pulp can also be used. When preparing nanocellulose, it can be prepared by referring to, for example, Cellulose Commun., 14 (2), 62 (2007), and International Publication No. 2018/230354 pamphlet.

When the nanocellulose in the present invention is produced using hypochlorous acid or a salt thereof, N- such as 2,2,6,6-tetramethyl-1-piperidin-N-oxy radical (hereinafter referred to as TEMPO) is used. It can be obtained without using an oxyl compound. It has been pointed out that the N-oxyl compound is harmful, and when nanocellulose is produced using this, the N-oxyl compound is contained in the nanocellulose. Therefore, it is preferable that the nanocellulose in the present invention contains substantially no N-oxyl compound.
In the present specification, "substantially free of N-oxyl compound" means that the N-oxyl compound is not used in producing the oxidized cellulose, or the nanocellulose or the oxidized cellulose is completely free of the N-oxyl compound. Or, it means that the content of the N-oxyl compound is 2.0 mass ppm or less with respect to the total amount of nanocellulose or oxidized cellulose, and is preferably 1.0 mass ppm or less. Further, even when the content of the N-oxyl compound is preferably 2.0 mass ppm or less, more preferably 1.0 mass ppm or less as an increase from the cellulosic raw material, "N-oxyl compound is substantially contained. It means "not included".
The residual nitrogen component can be measured by using a trace total nitrogen analyzer, and more specifically, by the method described in Examples.
One aspect of nanocellulose in the present invention is preferably derived from oxidized cellulose, which is an oxide of a cellulosic raw material due to hypochloric acid or a salt thereof, and is substantially free of N-oxyl compounds.

The above-mentioned oxidized cellulose can be said to be an oxide of a cellulosic raw material. Further, when a cellulosic raw material is oxidized with hypochlorous acid or a salt thereof to obtain oxidized cellulose, the oxidized cellulose can be said to be an oxide of the cellulosic raw material by hypochloric acid or a salt thereof.

The carboxy group is introduced into the cellulosic raw material by the above oxidation reaction. The carboxy group in the nanocellulose may be -COOH, may form a salt with a counter cation, or may be modified with another carboxy group or a compound capable of reacting with the salt thereof. Therefore, the nanocellulose contained in the resin composition of the present invention may contain a compound that modifies a countercation, a carboxy group or a salt thereof, and the nanocellulose in the present invention contains a countercation or a carboxy group or a salt thereof. It also includes embodiments that have reacted with the compound to be modified (ie, embodiments of the modified product). As will be described later, the resin composition of the present invention is produced by a production method including a step of modifying nanocellulose with a precipitant or a thermoplastic resin to separate it from a mixture with water. Therefore, it is preferable that the carboxy group in the nanocellulose contained in the resin composition of the present invention forms an interaction with a precipitating agent or a thermoplastic resin and is modified.

As described above, the resin composition of the present invention obtains a mixture of nanocellulose, a thermoplastic resin and an organic solvent, and partially or entirely of the organic solvent in the substantially absence of water from the obtained mixture. It can be manufactured by the method of removing. In the process of obtaining a mixture of the nanocellulose, the thermoplastic resin and the organic solvent, an inorganic salt or a precipitating agent such as an organic alkali or a cation containing a nitrogen atom in the molecule may be used. The addition of the precipitating agent can result in the reaction of nanocellulose with a compound that modifies a counter cation or a carboxy group or a salt thereof.
Further, in the process of obtaining a mixture of nanocellulose, a thermoplastic resin and an organic solvent, the carboxy group of nanocellulose may form an interaction with the thermoplastic resin. Therefore, the nanocellulose may be in a mode of reacting with the thermoplastic resin.

The cellulosic raw material in the present invention is not particularly limited as long as it is a material mainly composed of cellulose, and examples thereof include pulp, natural cellulose, regenerated cellulose, and fine cellulose depolymerized by mechanically treating the cellulosic raw material. Be done. As the cellulose-based raw material, a commercially available product such as crystalline cellulose made from pulp can be used as it is. In addition, unused biomass containing a large amount of cellulose components such as okara and soybean skin may be used as a raw material. Further, the cellulosic raw material may be treated with an alkali having an appropriate concentration for the purpose of facilitating the penetration of the oxidizing agent used in the next step into the raw material pulp.
The main component of the plant is cellulose, and a bundle of cellulose molecules is called a cellulose microfibril. Cellulose in the cellulosic raw material used in the present invention is also contained in the form of cellulosic microfibrils.

One aspect of the method for producing nanocellulose in the present invention is a step of oxidizing a cellulosic raw material to produce oxidized cellulose using hypochlorous acid having an effective chlorine concentration of 7 to 43% by mass or a salt thereof. It is a manufacturing method including a step of defibrating cellulose oxide to make it finer. The effective chlorine concentration in hypochlorous acid as an oxidizing agent or a salt thereof is preferably 14% by mass or more and 43% by mass or less, and more preferably 18% by mass or more and 43% by mass or less. When the effective chlorine concentration is 7% by mass or more, the reaction proceeds sufficiently and the oxidized cellulose tends to be efficiently obtained. When the effective chlorine concentration is 43% by mass or less, the self-decomposition tends to be suppressed and the handling tends to be easy.

The effective chlorine concentration in hypochlorous acid or its salt is a well-known concept and is defined as follows.
Hypochlorous acid is a weak acid that exists as an aqueous solution, and hypochlorite is a compound in which hydrogen of hypochlorous acid is replaced with another cation. Hypochlorite can exist as a solid with water of crystallization, but it has deliquescent properties and is a very unstable substance, and is generally treated as an aqueous solution.
For example, since sodium hypochlorite, which is a hypochlorite, is present only in the solution, the amount of effective chlorine in the solution is measured, not the concentration of sodium hypochlorite.
The effective chlorine of sodium hypochlorite is sodium hypochlorite (NaClO) because the oxidizing power of the divalent oxygen atom generated by the decomposition of sodium hypochlorite corresponds to the diatomic equivalent of monovalent chlorine. ) Has the same oxidizing power as the two atoms of unbound chlorine (Cl ₂ ), and effective chlorine = 2 × (chlorine in NaClO).
To measure the specific effective chlorine concentration, the sample is precisely weighed, water, potassium iodide, and acetic acid are added and left to stand, and the liberated iodine is titrated with a sodium thiosulfate solution using an aqueous starch solution as an indicator.

Examples of hypochlorous acid or a salt thereof include hypochlorous acid water, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, ammonium hypochlorite and the like. Of these, sodium hypochlorite is preferable from the viewpoint of ease of handling.
Hereinafter, one method for producing nanocellulose used in the present invention will be described by taking sodium hypochlorite as an example of hypochlorous acid or a salt thereof.

(1) A step of producing oxidized cellulose by oxidizing a cellulosic raw material using an aqueous sodium hypochlorite solution having an effective chlorine concentration of 7% by mass or more and 43% by mass or less.
As a method of adjusting the effective chlorine concentration of the sodium hypochlorite aqueous solution to 7% by mass or more and 43% by mass or less, a method of concentrating the sodium hypochlorite aqueous solution having an effective chlorine concentration lower than 7% by mass, and an effective chlorine concentration are There is a method of adjusting the sodium hypochlorite pentahydrate crystal having an amount of about 43% by mass as it is or by diluting it with water. Among these, adjusting to the effective chlorine concentration as an oxidizing agent by using sodium hypochlorite pentahydrate has less self-decomposition, that is, the decrease in the effective chlorine concentration is small, and the adjustment is easy. preferable.

The amount of the sodium hypochlorite aqueous solution having an effective chlorine concentration of 7% by mass or more and 43% by mass as an oxidizing agent can be selected within the range in which the oxidation reaction is promoted.
The method for mixing the cellulosic raw material and the sodium hypochlorite aqueous solution is not particularly limited, but from the viewpoint of ease of operation, it is preferable to add the cellulosic raw material to the sodium hypochlorite aqueous solution and mix them.

The reaction temperature in the oxidation reaction is preferably 15 ° C. or higher and 40 ° C. or lower, and more preferably 20 ° C. or higher and 35 ° C. or lower. In order to efficiently proceed with the oxidation reaction, the pH of the reaction system is preferably maintained at 7 or more and 14 or less, and more preferably 10 or more and 14 or less. An alkaline agent such as sodium hydroxide and an acid such as hydrochloric acid can be added to adjust the pH.
The reaction time of the oxidation reaction can be set according to the degree of progress of oxidation, but for example, it is preferable to carry out the reaction for about 15 minutes or more and 6 hours or less.

In the oxidation reaction, a carboxy group is introduced into the cellulosic raw material to produce oxidized cellulose. The amount of carboxy group of the oxidized cellulose is not particularly limited, but the amount of carboxy group per 1 g of oxidized cellulose is preferably 0.1 mmol / g or more and 3.0 mmol / g or less, and 0.2 mmol / g or more and 1.0 mmol. It is more preferably / g or less. Further, the oxidation reaction may be carried out in two stages.
Further, it is preferable that the amount of carboxy group is the same for nanocellulose. When the amount of carboxy group of nanocellulose is 0.1 mmol / g or more, it tends to be able to sufficiently interact with the thermoplastic resin and to form a fibrous complex. Further, since the amount of carboxy group of nanocellulose is 3.0 mmol / g or less, the viscosity of nanocellulose is suitable for mixing with a thermoplastic resin, and the workability of blending with a thermoplastic resin tends to be excellent. ..

The amount of carboxy group in cellulose oxide can be measured by the following method. Pure water is added to a 0.5 mass% slurry of cellulose oxide to prepare 60 ml, a 0.1 M aqueous solution of hydrochloric acid is added to adjust the pH to 2.5, and then a 0.05 N aqueous solution of sodium hydroxide is added dropwise to make the pH. The electric conductivity is measured until becomes 11, and it is calculated from the amount of sodium hydroxide (a) consumed in the neutralization step of a weak acid in which the change in the electric conductivity is moderate, using the following formula.
Amount of carboxy group (mmol / g cellulose oxide) = a (ml) x 0.05 / mass of cellulose oxide (g)

(2) Step of defibrating and refining cellulose oxide The nanocellulose used in the present invention is produced by defibrating and refining the cellulose oxide obtained in the above step as necessary. The method of defibrating may be limited to weak stirring with a stirrer or the like in a solvent, or mechanical defibration may be performed. Mechanical defibration makes it possible to shorten the defibration time.

The method of mechanical defibration is not particularly limited, but can be appropriately selected depending on the intended purpose after thoroughly washing the oxidized cellulose with a solvent, for example, a screw type mixer, a paddle mixer, a disper type mixer, etc. Turbine type mixer, homomixer under high speed rotation, high pressure homogenizer, ultra-high pressure homogenizer, double cylindrical homogenizer, ultrasonic homogenizer, water flow counter-collision type disperser, beater, disc type refiner, conical type refiner, double disc type refiner , Grinders, and known mixing / stirring devices such as uniaxial or multiaxial kneaders, and by treating them alone or in combination of two or more in a solvent, the oxidized cellulose is refined to obtain nanocellulose. Can be manufactured.

The solvent used for the defibration treatment is not particularly limited and may be appropriately selected depending on the intended purpose. Water, alcohols, ethers, ketones, N, N-dimethylformamide, N, N-dimethylacetamide. , And dimethylsulfoxide and the like. These may be used alone or in combination of two or more.

Examples of the alcohols include methanol, ethanol, isopropanol, isobutanol, sec-butyl alcohol, tert-butyl alcohol, methyl cellosolve, ethylene glycol, glycerin and the like.
Examples of the ethers include ethylene glycol dimethyl ether, 1,4-dioxane, and tetrahydrofuran.
Examples of the ketones include acetone, methyl ethyl ketone and the like.

By selecting an organic solvent as the solvent, it becomes easy to isolate the oxidized cellulose obtained in the above step and the nanocellulose obtained by defibrating it. Further, since nanocellulose dispersed in an organic solvent can be obtained, it becomes easy to mix with a resin that dissolves in the organic solvent, a resin raw material monomer, or the like.

The average fiber length of nanocellulose is usually in the range of 100 nm or more and 900 nm or less. When the average fiber length is in the range of 100 nm or more and 900 nm or less, the nanocellulose is coated with the thermoplastic resin, and the nanocellulose and the thermoplastic resin tend to easily form a fibrous composite. The average fiber length of nanocellulose is preferably 100 nm or more and 700 nm or less, and more preferably 100 nm or more and 400 nm or less. When the average fiber length is 100 nm or more and 700 nm or less, appropriate fluidity can be obtained for nanocellulose, and there is a tendency that the nanocellulose can be uniformly blended with the thermoplastic resin.

The average fiber width of nanocellulose is usually in the range of 1 nm or more and 10 nm or less. When the average fiber width is in the range of 1 nm or more and 10 nm or less, the nanocellulose is coated with the thermoplastic resin, and the nanocellulose and the thermoplastic resin tend to easily form a fibrous composite. The average fiber width of nanocellulose is preferably 2 nm or more and 10 nm or less, and more preferably 2.5 nm or more and 6 nm or less. When the average fiber width is 2 nm or more and 10 nm or less, appropriate fluidity can be obtained for nanocellulose, and there is a tendency that the nanocellulose can be uniformly blended with the thermoplastic resin.

In the nanocellulose in the present invention, the aspect ratio (average fiber length / average fiber width) represented by the ratio of the average fiber width to the average fiber length is preferably 20 or more and 200 or less. When the aspect ratio is 20 or more and 200 or less, the nanocellulose is coated with the thermoplastic resin, and the nanocellulose and the thermoplastic resin tend to easily form a fibrous composite. The aspect ratio is more preferably 190 or less, still more preferably 180 or less. The aspect ratio is more preferably 30 or more, still more preferably 40 or more.

As a method of adjusting the average fiber length and the average fiber width of the nanocellulose within the above range, for example, the conditions in the step of obtaining the above-mentioned oxidized cellulose or the step of defibrating the fiber to make it finer are adjusted. Can be mentioned.

For the average fiber width and average fiber length, nanocellulose and water were mixed so that the concentration of nanocellulose was approximately 1 to 10 ppm, and a sufficiently diluted cellulose aqueous dispersion was naturally dried on a mica substrate. The shape of nanocellulose was observed using a scanning probe microscope, and an arbitrary number of fibers were randomly selected from the obtained images. The cross-sectional height of the shape image = fiber width, and the peripheral length ÷ 2 = fiber length. It is a value calculated by. At this time, the image processing conditions are arbitrary, but the calculated values may differ depending on the image processing conditions even for the same image. The range of the difference in values depending on the image processing conditions is preferably within the range of ± 100 nm for the average fiber length. The range of the difference in values depending on the conditions is preferably within the range of ± 10 nm for the average fiber width. A more detailed measurement method follows the method described in Examples described later.

In one aspect of nanocellulose in the present invention, nanocellulose whose zeta potential and light transmittance satisfy the values described below may be used.

(Zeta potential)
In one aspect of nanocellulose used in the present invention, the zeta potential may be −30 mV or less. When the zeta potential is -30 mV or less (that is, the absolute value is 30 mV or more), repulsion between microfibrils is sufficiently obtained, and nanocellulose having a high surface charge density is likely to be generated. As a result, the dispersion stability of nanocellulose is improved, and the viscosity stability and handleability of the slurry tend to be excellent. From the viewpoint of dispersion stability, the lower limit of the zeta potential is not particularly limited. However, when the zeta potential is -100 mV or more (that is, the absolute value is 100 mV or less), oxidative cleavage in the fiber direction tends to be suppressed, so that nanocellulose having a uniform size tends to be obtained. ..

In the present specification, the zeta potential is a value measured under the conditions of pH 8.0 and 20 ° C. for a cellulose aqueous dispersion in which nanocellulose and water are mixed and the concentration of nanocellulose is 0.1% by mass. be.
Specifically, the zeta potential can be measured according to the following conditions.
Pure water is added to the aqueous dispersion of nanocellulose to dilute it so that the concentration of nanocellulose becomes 0.1%. Add 0.05 mol / L sodium hydroxide aqueous solution to the diluted nanocellulose aqueous dispersion to adjust the pH to about 8.0, and adjust the zeta potential with a zeta potential meter (ELSZ-1000) manufactured by Otsuka Electronics Co., Ltd. Measure at 20 ° C.

(Light transmittance)
In one aspect of nanocellulose used in the present invention, the light transmittance in the nanocellulose mixed solution mixed with water to a solid content concentration of 0.1% by mass may be 95% or more. The light transmittance is more preferably 96% or more, further preferably 97% or more, still more preferably 99% or more.
The light transmittance is a value measured by a spectrophotometer at a wavelength of 660 nm.

Specifically, the light transmittance can be measured according to the following conditions.
An aqueous dispersion of nanocellulose is placed in a 10 mm thick quartz cell, and the light transmittance at a wavelength of 660 nm is measured with a spectrophotometer (JASCO V-550).

As described above, one aspect of nanocellulose in the present invention can be obtained by oxidizing with hypochlorous acid or a salt thereof to obtain oxidized cellulose and then defibrating it.
Here, the degree of polymerization of the oxidized cellulose is not particularly limited, but is usually 600 or less. When the degree of polymerization of cellulose oxide exceeds 600, it tends to require a large amount of energy for defibration, it is not possible to exhibit sufficient defibration properties, and it tends to cause a decrease in dispersibility. Further, when the degree of polymerization of cellulose oxide exceeds 600, the amount of oxidized cellulose which is insufficiently defibrated increases, so that when the finely divided nanocellulose is dispersed in a dispersion medium, light scattering and the like increase. Transparency may decrease. Furthermore, the size of the obtained nanocellulose varies, and the quality tends to be non-uniform. Therefore, the viscosity of the slurry containing nanocellulose (hereinafter, also referred to as “nanocellulose-containing slurry”) may increase, and the handleability of the slurry may decrease. From the viewpoint of easy friability, the lower limit of the degree of polymerization of cellulose oxide is not particularly set. However, when the degree of polymerization of oxidized cellulose is less than 50, the proportion of particulate cellulose tends to increase rather than fibrous. From the above viewpoint, the degree of polymerization of cellulose oxide may be in the range of 50 or more and 600 or less.

The degree of polymerization of cellulose oxide can be adjusted by changing the reaction time, reaction temperature, pH, and the effective chlorine concentration of hypochlorous acid or a salt thereof during the oxidation reaction. Specifically, since the degree of polymerization tends to decrease as the degree of oxidation increases, for example, a method of increasing the reaction time and / or the reaction temperature of oxidation can be mentioned in order to reduce the degree of polymerization. As another method, the degree of polymerization of cellulose oxide can be adjusted by the stirring conditions of the reaction system at the time of the oxidation reaction. For example, under conditions in which the reaction system is sufficiently homogenized using a stirring blade or the like, the oxidation reaction proceeds smoothly and the degree of polymerization tends to decrease. On the other hand, under conditions such as stirring with a stirrer where stirring of the reaction system tends to be insufficient, the reaction tends to be non-uniform, and it is difficult to sufficiently reduce the degree of polymerization of cellulose oxide. In addition, the degree of polymerization of cellulose oxide tends to vary depending on the selection of the raw material cellulose. Therefore, the degree of polymerization of oxidized cellulose can be adjusted by selecting a cellulosic raw material. In the present specification, the degree of polymerization of cellulose oxide is the average degree of polymerization (viscosity average degree of polymerization) measured by the viscosity method.

Specifically, the degree of polymerization of cellulose oxide can be measured according to the following conditions.
Cellulose oxide is added to an aqueous solution of sodium borohydride adjusted to pH 10, and a reduction treatment is carried out at 25 ° C. for 5 hours. The amount of sodium borohydride is 0.1 g with respect to 1 g of cellulose oxide. After the reduction treatment, solid-liquid separation and washing with water were performed by suction filtration, and the obtained oxidized cellulose was freeze-dried. 0.04 g of dried cellulose oxide is added to 10 mL of pure water, and the mixture is stirred for 2 minutes, and then 10 mL of a 1 M copper ethylenediamine solution is added to dissolve the mixture. Then, the flow time of the blank solution and the flow time of the cellulose solution are measured at 25 ° C. with a capillary viscometer. From the flow time (t0) of the blank solution, the flow time (t) of the cellulose solution, and the concentration of oxidized cellulose (c [g / ml]), the relative viscosity (ηr), the specific viscosity (ηsp), and the intrinsic viscosity are as shown in the following equations. ([Η]) is sequentially obtained, and the degree of polymerization (DP) of cellulose oxide is calculated from the formula for measuring viscosity.
ηr = η / η0 = t / t0
ηsp ＝ ηr-1
[Η] = ηsp / (100 × c (1 + 0.28ηsp))
DP = 175 × [η]

(Light transmittance related to cellulose oxide)
The cellulose oxide is a nanocellulose aqueous dispersion obtained by defibrating an aqueous dispersion having a concentration of 0.1% by mass of the oxidized cellulose with a rotation / revolution stirrer at a revolution speed of 2000 rpm and a rotation speed of 800 rpm for 10 minutes. The light transmittance of the above is usually 60% or more. The light transmittance of the nanocellulose water dispersion obtained by defibrating the water dispersion having a concentration of 0.1% by mass of the cellulose oxide with a vortex mixer at a rotation speed of 3000 rpm for 10 minutes has a high transmittance. Usually 60% or more.
The light transmittance is a value measured by a spectrophotometer at a wavelength of 660 nm. The specific measurement method is as described in (Light transmittance).

One aspect of the oxidized cellulose used in the present invention preferably has a structure in which at least two of the hydroxyl groups of the glucopyranose ring constituting the cellulose are oxidized, and more specifically, the second aspect of the glucopyranose ring. It is preferable to have a structure in which the hydroxyl groups at the positions and 3 positions are oxidized and a carboxy group is introduced. Further, it is preferable that the hydroxyl group at the 6-position of the glucopyranose ring in the nanocellulose or oxidized cellulose is not oxidized and remains as a hydroxyl group. Such oxidized cellulose can be obtained, for example, by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof without using an N-oxyl compound. The position of the carboxy group in the glucopyranose ring of cellulose oxide can be analyzed by the solid ¹³ C-NMR spectrum.
The position of the carboxy group in the glucopyranose ring can be analyzed by comparing the solution NMR spectrum using rayon oxide as a model molecule and the solid ¹³ C-NMR spectrum of cellulose oxide.

Rayon has the same chemical structure as cellulose, and its oxide (rayon oxide) is water-soluble. By dissolving rayon oxide in heavy water and performing one-dimensional ¹³ C-NMR measurement of the solution, a peak of carbon attributed to the carboxy group is observed at 165 to 185 ppm. In one embodiment of the oxidized cellulose or nanocellulose used in the present invention obtained by oxidizing the raw material cellulose with hypochlorous acid or a salt thereof, two signals appear in this chemical shift range. Further, by solution two-dimensional NMR measurement, it can be determined that the carboxy group is introduced at the 2-position and the 3-position.

In the solid ¹³ C-NMR of oxidized cellulose or nanocellulose obtained by oxidizing the raw material cellulose with hypochlorous acid or a salt thereof, two signals appear at 165 to 185 ppm when the amount of carboxy group introduced is large. A very broad signal can appear when the amount of carboxy group introduced is small. As can be seen from the results of rayon oxide, the signals of the carboxy group carbons introduced at the 2- and 3-positions are close to each other, and the separation of the two signals is insufficient in the low-resolution solid ¹³ C-NMR. Therefore, when the amount of carboxy group introduced is small, it is observed as a broad signal. That is, in the solid ¹³ C-NMR spectrum, it can be confirmed that the carboxy group is introduced at the 2-position and the 3-position by evaluating the spread of the peak appearing at 165 to 185 ppm.
That is, two peak area values obtained by vertically dividing the area value at the peak top after obtaining the total area value by drawing a baseline on the peak in the range of 165 ppm to 185 ppm in the solid ¹³ C-NMR spectrum. A ratio (large area value / small area value) is obtained, and if the ratio of the peak area values is 1.2 or more, it can be said that the peak is broad.
The presence or absence of the broad peak can be determined by the ratio of the baseline length L in the range of 165 ppm to 185 ppm and the perpendicular length L'from the peak top to the baseline. That is, if the ratio L'/ L is 0.1 or more, it can be determined that a broad peak exists. The ratio L'/ L may be 0.2 or more, 0.3 or more, 0.4 or more, or 0.5 or more. The upper limit of the ratio L'/ L is not particularly limited, but usually it may be 3.0 or less, 2.0 or less, or 1.0 or less.
The structure of the glucopyranose ring can also be determined by analysis according to the method described in Sustainable Chem. Eng. 2020, 8, 48, 17800? 17806.

Nanocellulose in the present invention is a collection of fibers in units of one. When the nanocellulose in the present invention contains carboxylated nanocellulose, it suffices to contain at least one carboxylated nanocellulose, and it is preferable that the carboxylated nanocellulose is the main component. Here, the main component of the carboxylated nanocellulose is that the ratio of the carboxylated nanocellulose to the total amount of nanocellulose exceeds 50% by mass, preferably exceeds 70% by mass, and more preferably 80% by mass. Refers to being in excess. The upper limit of the above ratio is 100% by mass, but it may be 98% by mass or 95% by mass.

The nanocellulose in the present invention is blended with a thermoplastic resin, in which case the nanocellulose may contain a dispersion medium. The dispersion medium for nanocellulose in the present invention is not particularly limited as long as it disperses nanocellulose.
Examples of the dispersion medium include water, alcohols, ethers, ketones, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide and the like. These may be used alone or in combination of two or more. Specific examples of these dispersion media include the same examples as the solvent used for the defibration treatment.

As will be described later, the resin composition of the present invention may include a step of adding an amine or a quaternary ammonium as necessary in the production method thereof and precipitating the resin composition. This modifies at least a portion of the nanocellulose with amines or quaternary ammoniums. Further, at least a part of the nanocellulose may be modified with the amine or the quaternary ammonium by using the nanocellulose previously reacted with the amine or the quaternary ammonium in the production of the resin composition of the present invention. ..
Therefore, one of the preferred embodiments of the resin composition of the present invention comprises nanocellulose in which at least a portion of the nanocellulose has been modified with an amine or quaternary ammonium.

It is considered that the reaction of the amine or quaternary ammonium salt compound with the carboxy group on the surface of the nanocellulose modifies the nanocellulose, improves the hydrophobicity of the nanocellulose, and improves the affinity for ethylene unsaturated monomers and resins. Be done.

The amine that modifies nanocellulose is not particularly limited and may be primary, secondary, or tertiary. The number of carbon atoms of the hydrocarbon group or aromatic group bonded to the nitrogen atom of the amine or quaternary ammonium salt compound (if two or more hydrocarbon groups or aromatic groups are bonded to the nitrogen atom, the total carbon number) The number) is not particularly limited and may be selected from 1 to 100 carbon atoms. As the amine, an amine having a polyalkylene oxide structure such as an ethylene oxide / propylene oxide (EO / PO) copolymer may be used. From the viewpoint of imparting sufficient hydrophobicity to nanocellulose, the number of carbon atoms is preferably 3 or more, and more preferably 5 or more.

The quaternary ammonium salt compound that modifies nanocellulose is not particularly limited. Specifically, the quaternary ammonium salt compound includes a quaternary ammonium hydroxide such as tetrabutylammonium hydroxide, a quaternary ammonium chloride such as tetrabutylammonium chloride, and a quaternary ammonium bromide such as tetrabutylammonium bromide. A quaternary ammonium iodide such as tetrabutylammonium iodide can be considered.

<Thermoplastic resin>
The thermoplastic resin in the present invention is a polymer having a property of softening when it reaches the glass transition temperature or the melting point. The thermoplastic resin used in the present invention may be appropriately selected depending on the intended use of the resin, the type of the resin to be blended with the resin composition, and the like, and is not particularly limited. Examples of the thermoplastic resin include a resin containing an ethylenically unsaturated monomer or the like as a monomer unit. The ethylenically unsaturated monomer refers to a compound containing an ethylene group and polymerizing via the ethylene group to form a bond.

Examples of the monomer constituting the thermoplastic resin include (meth) acrylic acid; (meth) acrylic monomer such as alkyl (meth) acrylate and alkylene glycol (meth) acrylate; and nitrile-based monomer such as (meth) acrylonitrile; halogen. Vinyl carbonate; maleimide-based monomers such as imide maleate and phenylmaleimide; (meth) acrylamide-based monomers such as (meth) acrylamide; styrene-based monomers such as styrene and α-methylstyrene; vinyl acetate; and the like. Among these, (meth) acrylic monomers, (meth) acrylamide monomers, styrene monomers, maleimide monomers, and nitrile monomers are preferable. These may be contained alone or in combination of two or more.

Examples of the alkyl (meth) acrylate include those having an alkyl portion having 1 to 10 carbon atoms. The alkyl moiety may be linear, branched or cyclic, and may be unsubstituted or having a substituent.

The thermoplastic resin preferably has a functional group capable of forming a chemical bond with nanocellulose. The functional group is not particularly limited, and examples thereof include a carboxy group, a hydroxyl group, an epoxy group, an amino group, an amide group, and a cyano group. Having these functional groups enhances the affinity for nanocellulose. The proportion of the ethylenically unsaturated monomer having a functional group is preferably 5 mol% or less, more preferably 3 mol% or less, and 1 mol% or less of the total ethylenically unsaturated monomer. It is more preferable to have.

When the thermoplastic resin has a functional group capable of forming a chemical bond with nanocellulose, the functional group may be a base or a cation containing a nitrogen atom. As will be described later, as one of the methods for producing the resin composition of the present invention, an aqueous dispersion of nanocellulose and a thermoplastic resin are mixed, and the nanocellulose and the thermoplastic resin are reacted to precipitate the nanocellulose. A method including a step of taking out a mixture of the thermoplastic resin and the thermoplastic resin can be mentioned. According to this method, a mixture of nanocellulose and a thermoplastic resin can be obtained without using a precipitating agent, and a fibrous complex can be formed from the mixture.

As the base containing a nitrogen atom, an amine can be preferably mentioned. The amine is not particularly limited and may be primary, secondary, or tertiary. The number of carbon atoms of the hydrocarbon group or aromatic group bonded to the nitrogen atom of the amine or quaternary ammonium salt compound (if two or more hydrocarbon groups or aromatic groups are bonded to the nitrogen atom, the total carbon number) The number) is not particularly limited and may be selected from 1 to 100 carbon atoms. As the amine, an amine having a polyalkylene oxide structure such as an ethylene oxide / propylene oxide (EO / PO) copolymer may be used. From the viewpoint of imparting sufficient hydrophobicity to nanocellulose, the number of carbon atoms is preferably 3 or more, and more preferably 5 or more.
As the cation containing a nitrogen atom, quaternary ammonium can be preferably mentioned. The quaternary ammonium salt compound is not particularly limited, and is, for example, a quaternary ammonium hydroxide such as tetrabutylammonium hydroxide, a quaternary ammonium chloride such as tetrabutylammonium chloride, and a quaternary such as tetrabutylammonium bromide. Examples thereof include quaternary ammonium iodide such as ammonium bromide and tetrabutylammonium iodide.

One of the preferred embodiments of the thermoplastic resin is a polymer having a hydrophilic part and a hydrophobic part. Here, the hydrophilic portion refers to a portion composed of a hydrophilic monomer, and the hydrophobic portion refers to a portion composed of a hydrophobic monomer. The polymer having a hydrophilic portion and a hydrophobic portion is a copolymer composed of a portion composed of a hydrophilic monomer and a portion composed of a hydrophobic monomer. The type of the copolymer is not limited, and may be, for example, any type such as a random copolymer, a block copolymer, and a graft copolymer.
Examples of the hydrophobic monomer include (meth) acrylic acid alkyl ester compounds such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate; styrene. Aromatic vinyl compounds such as α-methylstyrene, vinyltoluene and vinylxylene; substituted maleimide-based monomers such as phenylmaleimide; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t. -Alkyl vinyl ethers having an alkyl group having 1 to 10 carbon atoms such as butyl vinyl ether, n-hexyl vinyl ether, 2-ethylhexyl vinyl ether, n-octyl vinyl ether, n-nonyl vinyl ether and n-decyl vinyl ether; vinyl formate, vinyl acetate, etc. Vinyl ester compounds such as vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl piperiate and vinyl versaticate; α-olefins such as ethylene, propylene and butylene; etc. Can be mentioned.
Examples of the hydrophilic monomer include unsaturated acids such as (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid and fumaric acid, and salts thereof; unsaturated acid anhydrides such as maleic anhydride; 2-acrylamide. Sulphonic acid group-containing monomers such as -2-methylpropanesulfonic acid and salts thereof; (meth) acrylic monomers such as 2-hydroxyethyl (meth) acrylate and alkylene glycol (meth) acrylate; (meth) acrylamide, ( (Meta) acrylamide-based monomers such as meta) acryloylmorpholin; methyl (meth) acrylamide, ethyl (meth) acrylamide, n-propyl (meth) acrylamide, isopropyl (meth) acrylamide, n-butyl (meth) acrylamide and 2-ethylhexyl N-alkyl (meth) acrylamide compounds such as (meth) acrylamide; (di) such as methylaminopropyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, ethylaminopropyl (meth) acrylamide and diethylaminopropyl (meth) acrylamide. Alkylaminoalkylamide compounds; (di) alkylaminoalkyl (meth) acrylate compounds such as methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; (Di) Alkylaminoalkyl (meth) acrylamide compounds such as dimethylaminopropylacrylamide; N-vinyllactam compounds such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam; Maleimide-based monomers such as maleimide; Vinyl alcohols; etc. Can be mentioned.

One of the preferred embodiments of the thermoplastic resin is a block copolymer having a hydrophilic segment and a hydrophobic segment. Here, the hydrophilic segment refers to one set composed of hydrophilic monomers in the block copolymer, and the hydrophobic segment refers to one set composed of hydrophobic monomers in the block copolymer. ..

The weight average molecular weight of the thermoplastic resin is not particularly limited. For example, it may be 50 to 3 million. When the weight average molecular weight is 5000 or more, the decrease in the strength of the resin is suppressed, and when the weight average molecular weight of the particles is 3 million or less, the particles are easily melted in the resin and a sufficient modification effect tends to be obtained.
The weight average molecular weight of the thermoplastic resin is preferably 10 to 2 million, more preferably 50 to 1 million.
The weight average molecular weight can be measured by a commercially available GPC (gel permeation chromatography), and in detail, it is measured by the method described in Examples.

The method for producing the thermoplastic resin is not particularly limited. As a method for producing a thermoplastic resin, for example, a method of emulsion polymerization, suspension polymerization or pickering emulsion polymerization of a monomer constituting the thermoplastic resin in the presence or absence of nanocellulose can be mentioned.

When the monomer is polymerized by emulsion polymerization or suspension polymerization in the presence of nanocellulose, the method is to disperse the nanocellulose and the monomer in a solvent such as water and heat the monomer with the polymerization initiator added. Can be mentioned.

As the polymerization initiator used for the polymerization, a general polymerization initiator such as a persulfate, an organic peroxide, or an azo compound can be used, but the persulfate is excellent in terms of polymerization reaction rate and productivity. Preferably, ammonium persulfate is more preferable because the obtained resin has excellent water resistance.

Examples of the persulfate include ammonium persulfate, potassium persulfate, sodium persulfate and the like. Examples of organic peroxides include t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propylperoxydicarbonato, and di-2-ethylhexylperoxydicarbonato. , T-Butyl Peroxy Vibalato, 2,2-Bis (4,4-di-t-Butyl Peroxycyclohexyl) Propane, 2,2-Bis (4,4-di-t-Amilperoxycyclohexyl) Propane, 2, 2-bis (4,4-di-t-octylperoxycyclohexyl) propane, 2,2-bis (4,4-di-α-cumylperoxycyclohexyl) propane, 2,2-bis (4,4-di) Examples thereof include -t-butylperoxycyclohexyl) butane and 2,2-bis (4,4-di-t-octylperoxycyclohexyl) butane.

Examples of the azo compound include 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-i-butylnitrile, and 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile. And so on.

The above-mentioned persulfate or peroxide may be used as a redox-based polymerization initiator in combination with the reducing agent sodium bisulfite or sodium ascorbate.

The temperature during the polymerization reaction is not particularly limited. For example, it is preferably in the range of 30 ° C to 180 ° C, and more preferably in the range of 50 ° C to 150 ° C.

When the monomer is polymerized in the presence of nanocellulose, the ratio of nanocellulose to the ethylenically unsaturated monomer is not particularly limited. For example, the amount of the ethylenically unsaturated monomer with respect to 100 parts by mass of nanocellulose may be 5 parts by mass to 1000 parts by mass, or 10 parts by mass to 100 parts by mass.

The solvent used in the polymerization reaction may or may not be removed. Further, the thermoplastic resin obtained by the above method may be used by being dispersed in another solvent after removing the solvent used in the polymerization reaction.

[Manufacturing method of resin composition]
The method for producing a resin composition of the present invention is a method for producing a resin composition containing nanocellulose and a thermoplastic resin. In the production method of the present invention, a solid content containing at least nanocellulose is precipitated from an aqueous mixture containing at least nanocellulose, and an organic solvent is added to the solid content through an operation of separating the solid content and the liquid phase. A step (also referred to as step A) of preparing a mixture (also referred to as mixture I) of nanocellulose, a thermoplastic resin and an organic solvent, and a part of the organic solvent from the mixture I in the absence of substantially water. Alternatively, it includes a step of removing the whole (also referred to as step B).
As used herein, "substantially in the absence of water" refers to the reduced content of water in Mixture I. Mixture I may contain water to the extent that it does not affect the acquisition of the resin composition. The content of water in the mixture I in step B in "substantially absent of water" may be 5% by weight or less, or 3% by weight or less, based on the total amount of the mixture I in step B. It may be 1 mass% or less.

In the production method of the present invention, a mixture I of nanocellulose, a thermoplastic resin and an organic solvent is prepared.
The details of the embodiments of the nanocellulose and the thermoplastic resin contained in the resin composition in the production method of the present invention are as described in the above-mentioned <nanocellulose> and <thermoplastic resin>.
The organic solvent referred to here is preferably an organic solvent that dissolves and / or swells the thermoplastic resin. Examples of the organic solvent include alcohol solvents, ketone solvents, ester solvents, ether solvents, nitrile solvents and the like. These may be used alone or in combination of two or more.

Examples of the alcohol solvent include methanol, ethanol, isopropanol, isobutanol, sec-butyl alcohol, tert-butyl alcohol, methyl cellosolve, ethylene glycol, glycerin and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone and the like.
Examples of the ester solvent include isoamyl acetate, ethyl acetate, propyl acetate, butyl acetate and the like.
Examples of the ether solvent include ethylene glycol dimethyl ether, 1,4-dioxane, and tetrahydrofuran (also referred to as THF).
Examples of the nitrile solvent include acetonitrile, benzonitrile, propionitrile, butyronitrile, adiponitrile and the like.

In step A in the production method of the present invention, conditions such as the blending order of these components are not limited as long as a mixture I of nanocellulose, a thermoplastic resin and an organic solvent can be obtained. Examples of the embodiment of the step A include, but are not limited to, steps A-1 to A-3 described later.

(Step A-1)
One of the aspects of step A (also referred to as step A-1) is a step of precipitating nanocellulose by adding a precipitating agent to the aqueous dispersion of nanocellulose and separating it from the liquid phase, and a step of separating the nanocellulose from the liquid phase.
The step of adding a thermoplastic resin and an organic solvent to the separated nanocellulose to obtain the mixture I is included.
The aqueous dispersion of nanocellulose is also referred to as an aqueous mixture. Therefore, the water mixture is the aqueous dispersion of nanocellulose itself.

(Step A-2)
One aspect of step A (also referred to as step A-2) is a mixture of nanocellulose and a thermoplastic resin II by adding a precipitant to an aqueous mixture of an aqueous dispersion of nanocellulose and a thermoplastic resin. The process of precipitating and separating from the liquid phase, and
The step of adding an organic solvent to the mixture II of the separated nanocellulose and the thermoplastic resin to obtain the mixture I is included.

(Step A-3)
In one of the embodiments of step A (also referred to as step A-3), an aqueous dispersion of nanocellulose and a thermoplastic resin are mixed, and the nanocellulose and the thermoplastic resin are reacted to precipitate the nanocellulose. The step of separating the mixture III with the thermoplastic resin from the liquid phase,
The step of adding an organic solvent to the mixture III of the separated nanocellulose and the thermoplastic resin to obtain the mixture I is included.

The water mixture in the present specification means a composition containing water as a constituent component. In the present specification, "separating from the liquid phase" is synonymous with "removing from the water mixture", and by separating the liquid phase containing at least a part of water contained in the water mixture from the solid component. Refers to taking out solid components. The nanocellulose, the mixture II, and the mixture III in the step A correspond to solid components. The nanocellulose, the mixture II, and the mixture III in the step A may not have the liquid phase completely removed, or may contain a part of the liquid phase. Separation of the liquid phase and the solid component can be performed, for example, by filtration. The solid component collected by filtration may be washed with an organic solvent.

The precipitant in steps A-1 and A-2 refers to a component having an action of precipitating nanocellulose, a thermoplastic resin, or a mixture of nanocellulose and a thermoplastic resin. As the precipitating agent, a component forming a salt with a carboxy group can be preferably mentioned.
In step A-3, the nanocellulose and the thermoplastic resin interact with each other to precipitate them without using a precipitating agent, and separate them from the aqueous mixture as a mixture III of the nanocellulose and the thermoplastic resin. Can be done.

Examples of the precipitant include an inorganic salt, an organic alkali or a cation containing a nitrogen atom in the molecule, and the like.
Examples of the inorganic salt include sodium chloride, magnesium chloride and the like.

Specific examples of the organic alkali containing a nitrogen atom in the molecule include primary, secondary, and tertiary amines. Specific examples of the cation include a quaternary ammonium salt compound. The number of carbon atoms of the hydrocarbon group or aromatic group bonded to the nitrogen atom of the amine or quaternary ammonium salt compound (if two or more hydrocarbon groups or aromatic groups are bonded to the nitrogen atom, the total carbon number) The number) is not particularly limited and may be selected from 1 to 100 carbon atoms. As the amine, an amine having a polyalkylene oxide structure such as an ethylene oxide / propylene oxide (EO / PO) copolymer may be used. From the viewpoint of imparting sufficient hydrophobicity to nanocellulose, the number of carbon atoms is preferably 3 or more, and more preferably 5 or more.

Specifically, the quaternary ammonium salt compound includes a quaternary ammonium hydroxide such as tetrabutylammonium hydroxide, a quaternary ammonium chloride such as tetrabutylammonium chloride, and a quaternary ammonium bromide such as tetrabutylammonium bromide. A quaternary ammonium iodide such as tetrabutylammonium iodide can be considered.

It is preferable that the separation step in the step A of the present invention is continuously performed. The continuous step of separation means that the operation is performed without interruption by simultaneously adding the constituent components and recovering the solid component. Specifically, in step A-1, it means that the aqueous dispersion of nanocellulose and the precipitating agent are continuously supplied and the nanocellulose is continuously recovered. In step A-2, it means that the aqueous dispersion of nanocellulose, the thermoplastic resin, and the precipitating agent are continuously supplied, and the mixture II is continuously recovered. In step A-3, it means that the aqueous dispersion of nanocellulose and the thermoplastic resin are continuously supplied and the mixture III is continuously recovered.

(Step A-4)
In step A in the production method of the present invention, a method of omitting the operation of separating the solid content and the liquid phase may be used in order to obtain the mixture I of nanocellulose, the thermoplastic resin and the organic solvent.
That is, one of the aspects of step A of the production method of the present invention (also referred to as step A-4) is step A for preparing a mixture I of nanocellulose, a thermoplastic resin, and an organic solvent, which is the step A. but,
A step of adding an organic alkali or cation containing a nitrogen atom in the molecule to the aqueous dispersion of nanocellulose and further adding a thermoplastic resin and an organic solvent to separate it from the aqueous phase to obtain the mixture I, or
It comprises a step of adding a thermoplastic resin and an organic solvent to an aqueous dispersion of nanocellulose, and further adding an organic alkali or cation containing a nitrogen atom in the molecule to separate it from the aqueous phase to obtain the mixture I.
The thermoplastic resin and the organic solvent may be added separately, or may be added as a mixture of the thermoplastic resin and the organic solvent. When the thermoplastic resin and the organic solvent are added separately, the order of addition thereof is arbitrary.

In the production method of the present invention, after the step A, a step B of removing a part or all of the organic solvent from the mixture I in the substantially absence of water is performed. The removal of the organic solvent can be performed, for example, by distilling off the solvent under reduced pressure.
The reduced pressure conditions may be appropriately adjusted depending on the physical characteristics of the organic solvent, and may be usually performed under reduced pressure in the range of 0 Torr or more and 30 Torr or less. Further, the organic solvent may be removed while heating. The temperature at the time of depressurization may be appropriately adjusted depending on the physical characteristics of the organic solvent, but is usually 10 ° C. or higher and 100 ° C. or lower.

The removal of the organic solvent may be performed by using a part of the organic solvent or removing all the organic solvents. The content of the organic solvent contained in the obtained resin composition is not particularly limited, but is usually in the range of 0% by mass or more and 100% by mass or less, and in the range of 0% by mass or more and 80% by mass or less with respect to the total amount of the resin composition. It may be in the range of 0% by mass or more and 70% by mass or less, or may be in the range of 0% by mass or more and 60% by mass or less.

[resin]
One of the present invention is a resin containing the resin composition of the present invention. The resin of the present invention is made from a resin composition. The resin of the present invention may be used as a resin by, for example, melting the resin composition as it is, and the resin composition of the present invention and the resin to be blended with the resin composition (hereinafter, also referred to as a raw material resin). May be produced by mixing.
Examples of the method for producing the resin of the present invention include a method in which a raw material resin is mixed with a resin composition as needed and heat-kneaded using an extruder. The resin of the present invention may be molded into a desired shape using a mold or the like.

The raw material resin is not particularly limited, and a known resin can be used.
Examples of the raw material resin include moldable resins such as thermoplastic resins and thermoplastic elastomers.
Examples of the thermoplastic resin include ABS (acrylonitrile-butadiene-styrene) resin, acrylic resin, polyolefin, polyester, polyurethane, polystyrene, polyamide, polyvinyl chloride, polycarbonate and the like.
Examples of the thermoplastic elastomer include olefin-based elastomers, styrene-based elastomers, polyamide-based elastomers, polyester-based elastomers, and polyurethane-based elastomers.

The raw material resin preferably contains the same components as those contained in the thermoplastic resin, or segments or functional groups having a good affinity with the thermoplastic resin. In particular, it is preferable that the same component as the component contained in the thermoplastic resin or a segment having a good affinity has a polymer alloy structure because effects such as shock absorption are imparted. If the affinity with the raw material resin is poor, the dispersibility of the obtained resin may be deteriorated, the appearance of the resin may be deteriorated, and the breaking stress and breaking elongation may be lowered.

The amount of the resin composition contained in the resin of the present invention is not particularly limited. When the resin composition of the present invention is used as a resin reforming composition, the amount of the resin composition with respect to 100 parts by mass of the raw material resin may be 0.1 part by mass to 10 parts by mass.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
Preparation of each sample and measurement of various physical properties were performed as follows.

<Kneading with resin>
The complex (resin composition) obtained in Examples and Comparative Examples was added to the ABS resin in an amount of 1 to 5% by mass (in terms of nanocellulose). Specifically, the resin composition and ABS resin pellets were mixed in a cup and then heat-kneaded using a plast mill. Kneading was started at a kneading temperature of 25 ° C. and gradually raised to a final kneading temperature of 160 ° C. and a total kneading time of 45 minutes. Then, it was pressed at 160 ° C. and 10 MPa for 5 minutes using a pressurizer and a die to form a flat plate of the kneaded product.
As the test piece for the bending test, a strip-shaped test piece having a width of 10 mm and a length of 40 mm (thickness of 1 mm) was prepared using the obtained flat plate-shaped kneaded product. As the test piece for the Charpy impact test, a strip-shaped test piece having a width of 10 mm and a length of 70 mm (thickness of 3 mm) was prepared using the obtained flat plate-shaped kneaded product.
Similarly, a test piece was prepared using ABS resin to which no resin composition was added.

<Mechanics evaluation>
A three-point bending test was performed using the test piece to measure elastic modulus, bending strength, bending strain or breaking strain. In addition, the impact resistance was evaluated by the Charpy impact test.

<Evaluation of breaking stress>
A bending test (test speed: 5 mm / min, distance between fulcrums: 30 mm) specified in JIS K 7171: 2016 was performed using a test piece, and the flexural modulus (MPa), breaking stress (MPa) and breaking strain (%) were performed. Was measured.

<Evaluation of impact resistance>
The Charpy impact test (notch tip radius: rN = 0.25 mm) specified in JIS K 711-1: 2012 was performed using the test piece, and the impact strength (kJ / m ² ) was measured.

<Microscopic observation>
The resin compositions obtained in Examples and Comparative Examples were observed with an electron microscope. As the electron microscope, a scanning electron microscope S-4800 manufactured by Hitachi High-Technologies Corporation was used. The magnification of the electron microscope was 45,000 to 50,000 times.
Regarding the results of electron microscopic observation of the resin composition, the resin composition in which the nanocellulose and the thermoplastic resin formed a fibrous composite and the thermoplastic resin had a structure in which the nanocellulose was coated was designated as 〇. .. Other structures are marked with x.

<Measurement of weight average molecular weight (Mw)>
The weight average molecular weight of the polymer of the thermoplastic resin was measured using GPC (gel permeation chromatography, HLC-8220, manufactured by Tosoh), and the weight average molecular weight (Mw) in terms of polystyrene was obtained. The GPC measurement conditions were as follows.
(Measurement condition)
Column: Tosoh TSKgel Supermultipore HZ-M x 3 Tosoh TSKgel Guard volume SuperMP (MZ) -M x 1 Solvent: THF
Temperature: 40 ° C
Detector: RI
Flow velocity: 0.3 mL / min
When the thermoplastic resin was obtained in the absence of nanocellulose, it was measured as described above.
When a resin composition containing nanocellulose and a thermoplastic resin was obtained by polymerization in the presence of nanocellulose, a solvent was added to the resin composition to dissolve the polymer. Then, it was filtered using a filter of 0.45 μm, and the obtained liquid was measured by polystyrene conversion.

<Making nanocellulose>
[Production Example 1: Preparation of Nanocellulose-1]
35 g of pulp (Theoras FD-101, Asahi Kasei Chemicals Co., Ltd., average particle diameter 50 μm, carboxy group amount 0.03 mmol / g) was added to 2800 g of pure water and stirred. To this was added 0.44 g of TEMPO, 4.4 g of sodium bromide, and 10 g of sodium hypochlorite (effective chlorine concentration 12% by mass). The oxidation reaction was carried out with 0.5 M sodium hydroxide while maintaining the pH at 10.5, and the reaction was terminated when the pH decrease accompanying the oxidation reaction almost stopped. After washing the obtained cellulose oxide with pure water, pure water is added so that the content of cellulose oxide becomes 1% by mass, and the defibration treatment is performed with an ultrasonic homogenizer. To this, 2200 g of t-butanol is added and mixed. , Centrifuged. Water was added to the obtained t-butanol solution to distill off t-butanol to prepare a dispersion containing 1.3% by mass of nanocellulose-1.

[Production Example 2: Preparation of Nanocellulose-2]
A sodium hypochlorous acid pentahydrate crystal (500 g) having an effective chlorine concentration of 43% by mass and pure water (1035.7 g) were mixed to prepare a solution having an effective chlorine concentration of 14% by mass. This solution was heated to 30 ° C., 35 g of pulp (Theoras FD-101) was added while stirring with a stirrer, and after further stirring with a stirrer for 30 minutes while maintaining the temperature at 30 ° C., 100 g of pure water was added. Then, suction filtration was performed with a 0.1 μm PTFE membrane filter to obtain oxidized cellulose. The obtained oxidized cellulose was defibrated with an ultrasonic homogenizer for 10 minutes, t-butanol was added thereto, mixed, and centrifuged. Pure water was added to the obtained t-butanol solution to distill off t-butanol to prepare a dispersion containing 1.3% by mass of nanocellulose-2.

[Production Example 3: Preparation of Nanocellulose-3]
A dispersion containing 1.3% by mass of nanocellulose-3 was prepared in the same manner as nanocellulose-2 except that the effective chlorine concentration of the solution was 30% by mass.

[Production Example 4: Preparation of Nanocellulose-4]
The same as Nanocellulose-2 was prepared except that the effective chlorine concentration of the solution was 43% by mass, and a dispersion containing 1.3% by mass of Nanocellulose-4 was prepared.
Table 1 shows the physical characteristics of nanocellulose-1 to nanocellulose-4 (denoted as CNF-1 to CNF-4 in the table).

The average fiber length and average fiber width of nanocellulose were measured by the following measuring methods.
The obtained nanocellulose dispersion is diluted 1000 to 1,000,000 times with pure water, air-dried on a mica substrate, and AC mode is used using a scanning probe microscope "MFP-3D infinity" manufactured by Oxford Asylum. Then, the shape of nanocellulose was observed.
The fiber length was binarized and analyzed using the image processing software "ImageJ". For 100 or more fibers, the average fiber length was calculated by setting fiber length = "peripheral length" / 2.
Regarding the fiber width, the average fiber width was obtained as the cross-sectional height of the shape image = the fiber width for 50 or more fibers using the software attached to "MFP-3D infinity".

[Example 1]
To 100 g of a dispersion containing nanocellulose (nanocellulose-1, nanocellulose concentration 1.3% by mass), 0.66 g of styrene, 0.28 g of acrylonitrile, and 0.35 g of a 1% by mass ammonium persulfate aqueous solution were added. After dispersing this with ultrasonic waves, the atmosphere was changed to a nitrogen atmosphere, and the mixture was heated at 70 ° C. for 4 hours with stirring for polymerization. After completion of the polymerization, 6.63 g of 0.5 M hydrochloric acid was added to the reaction solution and filtered, and a solution of 0.43 g of monododecylamine / 5 g of methanol was further added and stirred to precipitate nanocellulose-1 and resin fine particles. .. It was filtered and washed with methanol. To this mixture was added 36 g of methanol and stirred, and further 14.8 g of isoamyl acetate was added and stirred.
The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a composite of nanocellulose-1 and a polystyrene / acrylonitrile copolymer (that is, a resin composition).
The weight average molecular weight Mw of the copolymer was 358,000 (in terms of polystyrene).
The SEM image obtained by electron microscope observation of the resin composition of Example 1 is shown in FIG. As shown in FIG. 1, it was confirmed that the resin composition formed a fibrous complex and the thermoplastic resin had a structure coated with nanocellulose.

[Example 2]
To 100 g of a dispersion containing nanocellulose (nanocellulose-2, nanocellulose concentration 1.3% by mass), 3.93 g of styrene, 1.68 g of acrylonitrile, and 0.35 g of a 1% by mass ammonium persulfate aqueous solution were added. After dispersing this with ultrasonic waves, the atmosphere was changed to a nitrogen atmosphere, and the mixture was heated at 70 ° C. for 4 hours with stirring for polymerization. After completion of the polymerization, 1.40 g of 0.5 M hydrochloric acid is added to the reaction solution and filtered, and 0.32 g of a 40% tetrabutylammonium hydroxide aqueous solution is further added and stirred to precipitate nanocellulose-2 and resin fine particles. rice field. It was filtered and washed with methanol. To this mixture was added 110 g of MEK and stirred, and further 45.8 g of isoamyl acetate was added and stirred.
The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose-2 and a polystyrene / acrylonitrile copolymer.
The weight average molecular weight Mw of the copolymer was 817,000 (in terms of polystyrene).

[Example 3]
To 100 g of a dispersion containing nanocellulose (nanocellulose-3, nanocellulose concentration 1.3% by mass), 1.45 g of styrene, 0.62 g of acrylonitrile, and 0.35 g of a 1% by mass ammonium persulfate aqueous solution were added. After dispersing this with ultrasonic waves, the atmosphere was changed to a nitrogen atmosphere, and the mixture was heated at 70 ° C. for 4 hours with stirring for polymerization. After completion of the polymerization, nanocellulose-3 and resin fine particles were precipitated using sodium chloride as a salting out agent. It was filtered and washed with methanol. 52 g of IPA was added to this mixture and stirred, and 22.3 g of isoamyl acetate was further added and stirred.
The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose-3 and a polystyrene / acrylonitrile copolymer.
The weight average molecular weight Mw of the copolymer was 519000 (in terms of polystyrene).

[Example 4]
To 100 g of a dispersion containing nanocellulose (nanocellulose-4, nanocellulose concentration 1.3% by mass), 0.92 g of methyl methacrylate and 0.35 g of a 1% by mass ammonium persulfate aqueous solution and 0.03 g of n-octyl thioglycolate were added. added. After dispersing this with ultrasonic waves, the atmosphere was changed to a nitrogen atmosphere, and the mixture was heated at 70 ° C. for 4 hours with stirring for polymerization. After completion of the polymerization, 5.85 g of 0.5 M hydrochloric acid is added to the reaction solution and filtered, and 2.47 g of a 25% hexadecyltrimethylammonium hydroxide aqueous solution is further added and stirred to precipitate nanocellulose-4 and resin fine particles. I let you. It was filtered and washed with methanol. 35 g of methanol was added to this mixture and the mixture was stirred.
Methanol was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose-4 and pMMA.
The weight average molecular weight Mw of the copolymer was 776,000 (in terms of polystyrene).

[Example 5]
0.24 g of methyl methacrylate and 0.35 g of 1% by mass ammonium persulfate aqueous solution and 0.03 g of n-octyl thioglycolate in 100 g of a dispersion containing nanocellulose (nanocellulose-2, nanocellulose concentration 1.3% by mass). added. After dispersing this with ultrasonic waves, the atmosphere was changed to a nitrogen atmosphere, and the mixture was heated at 70 ° C. for 4 hours with stirring for polymerization. After completion of the polymerization, 1.40 g of 0.5 M hydrochloric acid was added to the reaction solution and filtered, and a solution of 0.09 g of monododecylamine / 5 g of methanol was further added and stirred to precipitate nanocellulose-2 and resin fine particles. .. This was filtered, washed with methanol, 24 g of methanol was added to the mixture and stirred, and 10.2 g of isoamyl acetate was further added and stirred.
The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose and pMMA.
The weight average molecular weight Mw of the copolymer was 450,000 (in terms of polystyrene).

[Example 6]
To 63.9 g of acetonitrile, 9.8 g of styrene, 16.3 g of N-phenylmaleimide, and 0.8 g of ABN-E as an initiator were added, and the mixture was polymerized by heating and stirring at 70 ° C. under nitrogen bubbling for 8 hours. Then, the solvent was distilled off with a dryer to obtain a polymer P-1 (Mw = 28,000, in terms of polystyrene).
Put 100 g of a dispersion containing nanocellulose (nanocellulose-4, nanocellulose concentration 1.3% by mass) in another container, add 0.38 g of monododecylamine / 5 g of methanol solution, and stir to add nanocellulose-4. It was precipitated. It was filtered and washed with methanol. A solution consisting of 0.92 g of polymer P-1 and 14.5 g of THF was added to this mixture and stirred.
The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose and the polymer P-1.

[Example 7]
To 63.9 g of acetonitrile, 9.8 g of styrene, 16.3 g of N-phenylmaleimide, 1.32 g of BORON MOLECULAR BM1429 as an initiator, and 0.08 g of ABN-E as an initiator are added, and the temperature is 70 ° C. under nitrogen bubbling for 4 hours. It was polymerized by heating and stirring. After a predetermined time, the internal temperature was once lowered to 30 ° C., 9.0 g of methoxypolyethylene glycol (n = 9) monoacrylate was added, and the mixture was again heated and stirred at 70 ° C. for 4 hours for polymerization. After completion of the polymerization, the solvent was distilled off with a dryer to obtain a block copolymer P-2 (Mw = 8000, in terms of polystyrene).
Put 100 g of a dispersion containing nanocellulose (nanocellulose-2, nanocellulose concentration 1.3% by mass) in another container, add 0.59 g of a 25% hexadecyltrimethylammonium hydroxide aqueous solution, and stir to obtain nanocellulose. It was precipitated, filtered and washed with methanol.
A solution consisting of 0.47 g of polymer P-2 and 11.6 g of acetone was added to this mixture and stirred. The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose-2 and the block copolymer P-2.

[Example 8]
To 63.9 g of acetonitrile, 9.8 g of styrene, 16.3 g of N-phenylmaleimide, 1.32 g of BORON MOLECULAR BM1429 as an initiator, and 0.08 g of ABN-E as an initiator are added, and the temperature is 70 ° C. under nitrogen bubbling for 4 hours. It was polymerized by heating and stirring. After a predetermined time, the internal temperature was once lowered to 30 ° C., 9.0 g of methoxypolyethylene glycol (n = 9) monoacrylate was added, and the mixture was again heated and stirred at 70 ° C. for 4 hours for polymerization. After completion of the polymerization, the solvent was distilled off with a dryer to obtain a block copolymer P-2 (Mw = 8000, in terms of polystyrene).
Put 100 g of a dispersion containing nanocellulose (nanocellulose-2, nanocellulose concentration 1.3% by mass) in another container, add 0.09 g of monododecylamine / 5 g of methanol solution, and stir to precipitate nanocellulose. , This was filtered and washed with methanol.
A solution consisting of 0.47 g of polymer P-2 and 11.6 g of isoamyl acetate was added to this mixture and stirred. 50% of the added isoamyl acetate was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a composite of nanocellulose-2 / block copolymer P-2 / isoamyl acetate.

[Example 9]
To 63.9 g of acetonitrile, 9.8 g of styrene, 16.3 g of N-phenylmaleimide, 1.32 g of BORON MOLECULAR BM1429 as an initiator, and 0.08 g of ABN-E as an initiator are added, and the temperature is 70 ° C. under nitrogen bubbling for 4 hours. It was polymerized by heating and stirring. After a predetermined time, the internal temperature was once lowered to 30 ° C., 9.0 g of acrylamide (powder) was added, and the mixture was again heated and stirred at 70 ° C. for 4 hours for polymerization. After completion of the polymerization, the solvent was distilled off with a dryer to obtain a block copolymer P-3 (Mw = 8000, in terms of polystyrene).
Put 100 g of a dispersion containing nanocellulose (nanocellulose-3, nanocellulose concentration 1.3% by mass) in another container, add 0.12 g of monododecylamine / 5 g of methanol solution, and stir to precipitate nanocellulose. , This was filtered and washed with methanol.
A solution consisting of 0.44 g of polymer P-3 and 11.4 g of acetonitrile was added to this mixture and stirred. The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose-3 and the block copolymer P-3.

[Example 10]
To 63.9 g of acetonitrile, 9.8 g of styrene, 16.3 g of N-phenylmaleimide, 1.32 g of BORON MOLECULAR BM1429 as an initiator, and 0.08 g of ABN-E as an initiator are added, and the temperature is 70 ° C. under nitrogen bubbling for 4 hours. It was polymerized by heating and stirring. After a predetermined time, the internal temperature was once lowered to 30 ° C., 9.0 g of methoxypolyethylene glycol (n = 9) monoacrylate was added, and the mixture was again heated and stirred at 70 ° C. for 4 hours for polymerization. After completion of the polymerization, the solvent was distilled off with a dryer to obtain a block copolymer P-4 (Mw = 8000, in terms of polystyrene).
In another container, put 100 g of a dispersion containing nanocellulose (nanocellulose-3, nanocellulose concentration 1.3% by mass), add 0.42 g of 40% tetrabutylammonium hydroxide, and stir to precipitate nanocellulose. , This was filtered and washed with methanol.
A solution consisting of 0.21 g of the polymer P-4 and 9.9 g of isoamyl acetate was added to this mixture, and the mixture was stirred. The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose-3 and the block copolymer P-4.

[Example 11]
To 63.9 g of acetonitrile, 9.8 g of styrene, 16.3 g of N-phenylmaleimide, 1.32 g of BORON MOLECULAR BM1429 as an initiator, and 0.08 g of ABN-E as an initiator are added, and the temperature is 70 ° C. under nitrogen bubbling for 4 hours. It was polymerized by heating and stirring. After a predetermined time, the internal temperature is once lowered to 30 ° C., 7.8 g of methoxypolyethylene glycol (n = 9) monoacrylate and 0.78 g of N- [3- (dimethylamino) propyl] acrylamide (DMAPAA) are added, and 70 again. Polymerization was carried out by heating and stirring at ° C. for 4 hours to obtain an acetonitrile solution of block copolymer P-5 (Mw = 8000, polystyrene equivalent). 1.58 g of this solution was emulsified into 10 g of water while irradiating with ultrasonic waves.
Put 100 g of a dispersion containing nanocellulose (nanocellulose-4, nanocellulose concentration 1.3% by mass) in another container, add the emulsified solution of block copolymer P-5, and combine nanocellulose and P-5. The body was precipitated. It was filtered and washed with methanol.
12.2 g of acetonitrile was added to this mixture and the mixture was stirred. The solvent was distilled off under reduced pressure (2 Torr, 50 ° C. × 7 hr) to obtain a complex of nanocellulose-4 and the block copolymer P-5.

[Comparative Example 1]
To 100 g of a dispersion containing nanocellulose (nanocellulose-1, nanocellulose concentration 1.3% by mass), 3.34 g of styrene, 1.43 g of acrylonitrile, and 0.35 g of a 1% by mass ammonium persulfate aqueous solution were added. After dispersing this with ultrasonic waves, the atmosphere was changed to a nitrogen atmosphere, and the mixture was heated at 70 ° C. for 4 hours with stirring for polymerization. After completion of the polymerization, 6.63 g of 0.5 M hydrochloric acid was added to the reaction solution, and the mixture was filtered. To this, a solution of 0.43 g of monododecylamine / 5 g of methanol was added and stirred to precipitate nanocellulose and resin fine particles, which was filtered to distill off the solvent under reduced pressure (2 Torr, 50 ° C. × 7 hr). A composite of nanocellulose-1 and a polystyrene / acrylonitrile copolymer (nanocellulose concentration 20% by mass) was obtained.
The weight average molecular weight Mw of the copolymer was 755,000 (in terms of polystyrene).
The SEM image obtained by electron microscope observation of the resin composition of Comparative Example 1 is shown in FIG. It was confirmed that the resin composition did not form a fibrous complex as shown in FIG.

[Comparative Example 2]
Treatment was carried out in the same manner as in Comparative Example 1 except that nanocellulose-2 was used as the nanocellulose to obtain a composite of nanocellulose-2 and a polystyrene / acrylonitrile copolymer (nanocellulose concentration 50% by mass).
[Comparative Example 3]
Nanocellulose-2 was used as the nanocellulose and treated in the same manner as in Comparative Example 2 to obtain a composite of nanocellulose-2 and a polystyrene / acrylonitrile copolymer (nanocellulose concentration 70% by mass).
[Comparative Example 4]
Treatment was carried out in the same manner as in Comparative Example 1 except that nanocellulose-3 was used as the nanocellulose to obtain a composite of nanocellulose-3 and a polystyrene / acrylonitrile copolymer (nanocellulose concentration 80% by mass).

Table 2 shows the physical characteristics of the complexes of Examples 1 to 11 and Comparative Examples 1 to 4.

Table 3 shows the details of the manufacturing methods a to i in Table 2.

Table 4 shows the physical characteristics and evaluation results of the test pieces.

The bending strength of the test piece of the ABS resin to which the resin composition was not added was 67.6 MPa.

The resin composition of the present invention can reinforce the resin and has industrial applicability in the field of reinforced resin.

Claims

Contains nanocellulose and thermoplastics
The nanocellulose and the thermoplastic resin form a fibrous complex.
Resin composition.
The amount of carboxy group of the nanocellulose is 0.1 mmol / g or more and 3.0 mmol / g or less.
The resin composition according to claim 1.
The content of the nanocellulose is 50% by mass or more with respect to the total amount of the resin composition.
The resin composition according to claim 1 or 2.
The thermoplastic resin contains at least one monomer unit selected from (meth) acrylic monomer, (meth) acrylamide-based monomer, styrene-based monomer, maleimide-based monomer, and nitrile-based monomer as a constituent unit.
The resin composition according to any one of claims 1 to 3.
The thermoplastic resin has a functional group capable of forming a chemical bond with the nanocellulose.
The resin composition according to any one of claims 1 to 4.
The functional group is a base or cation containing a nitrogen atom.
The resin composition according to claim 5.
The thermoplastic resin is a polymer having a hydrophilic portion and a hydrophobic portion.
The resin composition according to any one of claims 1 to 6.
The thermoplastic resin is a block copolymer having a hydrophilic segment and a hydrophobic segment.
The resin composition according to any one of claims 1 to 7.
A method for producing a resin composition containing nanocellulose and a thermoplastic resin.
After precipitating at least the solid content containing nanocellulose from the aqueous mixture containing at least nanocellulose and separating the solid content from the liquid phase, an organic solvent is added to the solid content, and the nanocellulose and the thermoplastic resin are added. Step A to prepare the mixture I of and the organic solvent, and
A step B of removing some or all of the organic solvent from the mixture I in the absence of substantially the presence of water.
Production method.
The organic solvent is an organic solvent that dissolves and / or swells the thermoplastic resin.
The manufacturing method according to claim 9.
The organic solvent contains at least one selected from an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, and a nitrile solvent.
The manufacturing method according to claim 9 or 10.
The step A is
A step of precipitating nanocellulose by adding a precipitating agent to the aqueous dispersion of nanocellulose and separating it from the liquid phase, and
The step of adding a thermoplastic resin and an organic solvent to the separated nanocellulose to obtain the mixture I is included.
The manufacturing method according to any one of claims 9 to 11.
The step A is
A step of precipitating a mixture II of nanocellulose and a thermoplastic resin by adding a precipitating agent to an aqueous mixture of an aqueous dispersion of nanocellulose and a thermoplastic resin, and separating the mixture from the liquid phase.
The step of adding an organic solvent to the mixture II of the separated nanocellulose and the thermoplastic resin to obtain the mixture I is included.
The manufacturing method according to any one of claims 9 to 11.
The precipitating agent is an inorganic salt.
The manufacturing method according to claim 12 or 13.
The precipitating agent is an organic alkali or cation containing a nitrogen atom in the molecule.
The manufacturing method according to claim 12 or 13.
The step A is
A step of mixing an aqueous dispersion of nanocellulose and a thermoplastic resin, reacting the nanocellulose with the thermoplastic resin to precipitate, and separating the mixture III of the nanocellulose and the thermoplastic resin from the liquid phase.
The step of adding an organic solvent to the mixture III of the separated nanocellulose and the thermoplastic resin to obtain the mixture I is included.
The manufacturing method according to any one of claims 9 to 11.
The separation step is continuously performed.
The manufacturing method according to any one of claims 12 to 16.
A method for producing a resin composition containing nanocellulose and a thermoplastic resin.
Step A to prepare a mixture I of nanocellulose, a thermoplastic resin, and an organic solvent, and
Including step B of removing some or all of the organic solvent from the mixture I in the absence of substantially the presence of water.
The step A is
A step of adding an organic alkali or cation containing a nitrogen atom in the molecule to the aqueous dispersion of nanocellulose and further adding a thermoplastic resin and an organic solvent to separate it from the aqueous phase to obtain the mixture I, or
Production including a step of adding a thermoplastic resin and an organic solvent to an aqueous dispersion of nanocellulose, and further adding an organic alkali or cation containing a nitrogen atom in the molecule to separate it from the aqueous phase to obtain the mixture I. Method.
The organic solvent is an organic solvent that dissolves and / or swells the thermoplastic resin.
The manufacturing method according to claim 18.
The organic solvent contains at least one selected from an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, and a nitrile solvent.
The manufacturing method according to claim 18 or 19.
A resin containing the resin composition according to any one of claims 1 to 8.
A melt containing the resin composition according to any one of claims 1 to 8 and the resin.
The resin according to claim 21.
Pellet-like,
The resin according to claim 21 or 22.
It is a method for manufacturing pellet-shaped resin.
A step of blending the resin composition according to any one of claims 1 to 8 and a resin, if necessary, and melt-kneading the resin composition, and
A manufacturing method comprising a step of pelletizing after the melt kneading.