JP6429978B2 - Resin composition and method for producing the same - Google Patents

Description

  The present invention relates to a resin composition containing cellulose nanofibers and a method for producing the same.

  As a transparent plastic substrate for replacing glass, a transparent heat-resistant resin having flexibility and transparency and having heat resistance, a high glass transition point, and a low linear thermal expansion coefficient is required. As such materials, for example, super engineering plastics such as transparent polyimide and polyethersulfone are known. However, these materials have a high coefficient of linear thermal expansion, and are not sufficient as substitute materials for glass. In addition, the price is high and it is not economically suitable as an industrial product.

  By the way, various attempts have been made to enhance the properties of the resin by mixing cellulose nanofibers obtained by oxidizing natural cellulose fibers in the presence of an N-oxyl compound with a resin to form a resin composition. For example, in Patent Document 1, a reaction product fiber obtained by allowing an N-oxyl compound and a cooxidant to act on natural cellulose fiber is treated with an organic onium compound to obtain a finely modified cellulose fiber. And epoxy resin are mixed to obtain an epoxy resin composite. In Patent Document 2, for the purpose of obtaining a resin composition having a low linear expansion coefficient and high transparency, an organic fiber composed of cellulose nanofibers having a diameter of 4 to 1000 nm and an organic cation compound is hydrophobic. It is described that it is contained in a functional resin. Apart from these, Patent Document 3 describes a transparent wiring substrate containing cellulose fibers having an average fiber diameter of 4 to 200 nm and a matrix made of an inorganic polymer, a natural polymer or a synthetic polymer. ing.

JP 2010-59304 A JP 2011-47084 A JP 2011-1559 A

  However, it is not easy to sufficiently disperse cellulose nanofibers in a resin by a conventionally known method. Moreover, in order to improve the characteristics of the resin, a relatively large amount of cellulose nanofiber is required.

  Therefore, the subject of this invention is providing the resin composition containing the cellulose nanofiber which can eliminate the fault which the prior art mentioned above has, and its manufacturing method.

The present invention is a resin composition containing cellulose nanofibers and a thermosetting resin,
The present invention provides a resin composition in which the cellulose nanofiber is a cellulose nanofiber composite in which a hydrocarbon group is bonded through an amide bond.

The present invention is a resin composition containing cellulose nanofibers and a thermosetting resin,
Furthermore, the present invention provides a resin composition containing an alkyl imidazoline dispersant.

In addition, the present invention provides a suitable method for producing the resin composition as described above.
(A1) A cellulose nanofiber composite formed by bonding a hydrocarbon group via an amide bond and a thermosetting resin prepolymer before thermosetting are mixed to obtain a mixture,
(A2) Molding the mixture into a predetermined shape to obtain a molded body,
(A3) The present invention provides a method for producing a resin composition comprising a step of thermosetting the prepolymer in the molded body.

Furthermore, the present invention provides a method for producing the resin composition as described above.
(B1) Cellulose nanofibers, a thermosetting resin prepolymer before thermosetting, and an alkylimidazoline-based dispersant are mixed to obtain a mixture,
(B2) Molding the mixture into a predetermined shape to obtain a molded body,
(B3) The present invention provides a method for producing a resin composition having a step of thermosetting the prepolymer in the molded body.

  ADVANTAGE OF THE INVENTION According to this invention, the resin composition containing a cellulose nanofiber which has a low linear thermal expansion coefficient is provided. Moreover, according to this invention, such a resin composition can be manufactured easily.

  Hereinafter, the present invention will be described based on preferred embodiments thereof. The resin composition of the present invention contains cellulose nanofiber as one of its constituent components. Cellulose nanofibers preferably have an average fiber diameter of 200 nm or less. The average fiber diameter of the cellulose nanofiber is preferably 1 nm or more, and preferably 200 nm or less, more preferably 100 nm or less, and particularly preferably 50 nm or less. More specifically, it is preferably 1 nm to 200 nm, more preferably 1 nm to 100 nm, and particularly preferably 1 nm to 50 nm. The average fiber diameter is measured by the following measuring method.

<Measurement method of average fiber diameter>
A cellulose nanofiber aqueous dispersion having a solid content concentration of 0.0001% by mass was prepared, and the dispersion was dropped onto mica (mica) and dried to obtain an observation sample. Atomic force microscope (NanoNaVi II, SPA400) , Manufactured by SII NanoTechnology Co., Ltd., and the probe uses SI-DF40Al manufactured by the same company), and the fiber height of the cellulose nanofiber in the observation sample is measured. And in the microscope image which can confirm a cellulose nanofiber, five or more cellulose nanofibers are extracted, and an average fiber diameter is computed from those fiber heights. In general, the smallest unit of cellulose nanofibers prepared from higher plants is packed in a square shape with 6 x 6 molecular chains, so the height that can be analyzed with an atomic force microscope image is the width of the fiber. Can be considered.

  In addition to being fine (the average fiber diameter is preferably 200 nm or less), the cellulose nanofibers preferably have a cellulose carboxyl group content within a predetermined range. Specifically, the carboxyl group content of cellulose constituting the cellulose nanofiber is preferably 0.1 mmol / g or more, more preferably 0.4 mmol / g or more, particularly preferably 0.6 mmol / g or more, And it is preferably 3 mmol / g or less, more preferably 2 mmol / g or less, and particularly preferably 1.8 mmol / g or less. More specifically, it is preferably 0.1 mmol / g or more and 3 mmol / g or less, more preferably 0.4 mmol / g or more and 2 mmol / g or less, and particularly preferably 0.6 mmol / g or more and 1.8 mmol / g or less. .

  The carboxyl group content of the cellulose constituting the cellulose nanofiber is preferably 0.1 mmol / g or more and 3 mmol / g or less, so that cellulose nanofibers having a fine average fiber diameter of preferably 200 nm or less can be stably formed. It is an important factor in obtaining. That is, in the process of biosynthesis of natural cellulose, normally, cellulose nanofibers called microfibrils are first formed, and these are bundled to form a higher-order solid structure. In order to weaken the hydrogen bonds between the surfaces that are the driving force of strong cohesion between microfibrils in naturally derived cellulose solid raw materials, some of them are oxidized, Obtained by conversion to a carboxyl group. Therefore, the larger the total amount of carboxyl groups (carboxyl group content) present in cellulose, the smaller the fiber diameter, the more stable it can exist, and in water, an electrical repulsive force is generated. In addition, the tendency of the microfibrils to break apart without maintaining aggregation is increased, and the dispersion stability of the cellulose nanofibers is further increased. The carboxyl group content of the cellulose nanofiber is measured by the following measurement method.

<Measurement method of carboxyl group content>
Take a cellulose nanofiber with a dry mass of 0.5 g in a 100 ml beaker, add ion exchange water to make a total of 55 ml, add 5 ml of 0.01 M sodium chloride aqueous solution to prepare a dispersion, and fully disperse the cellulose nanofiber. The dispersion is stirred until 0.1M hydrochloric acid is added to this dispersion to adjust the pH to 2.5-3, and 0.05M sodium hydroxide aqueous solution is waited for using an automatic titrator (AUT-50, manufactured by Toa DKK Co., Ltd.). The solution is dropped into the dispersion under conditions of 60 seconds, and the conductivity and pH values are measured every minute. Measurement is continued until pH 11 is obtained to obtain a conductivity curve. From this conductivity curve, the sodium hydroxide titration amount is obtained, and the carboxyl group content of the cellulose nanofiber is calculated by the following formula.
Carboxyl group content (mmol / g) = sodium hydroxide titration × sodium hydroxide aqueous solution concentration (0.05 M) / mass of cellulose nanofiber (0.5 g)

  Cellulose nanofibers can be obtained, for example, by a production method including an oxidation reaction step in which a natural cellulose fiber is oxidized to obtain a reactant fiber, and a refinement step in which the reactant fiber is refined. Each step will be described in detail below.

  In the oxidation reaction step, first, a slurry in which natural cellulose fibers are dispersed in water is prepared. The slurry is obtained by adding about 10 times to about 1000 times (mass basis) of water to the natural cellulose fiber (absolute dry basis) as a raw material, and processing with a mixer or the like. Examples of natural cellulose fibers include wood pulp such as softwood pulp and hardwood pulp; cotton pulp such as cotton linter and cotton lint; non-wood pulp such as straw pulp and bagasse pulp; and bacterial cellulose. These 1 type can be used individually or in combination of 2 or more types. The natural cellulose fiber may be subjected to a treatment for increasing the surface area such as beating.

  Next, a natural fiber is oxidized in water using an N-oxyl compound as an oxidation catalyst to obtain a reactant fiber. Examples of N-oxyl compounds that can be used as an oxidation catalyst for cellulose include 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (hereinafter also referred to as TEMPO), 4-acetamide-TEMPO, 4-carboxy-TEMPO, 4-phosphonooxy-TEMPO, etc. can be used. The addition of these N-oxyl compounds is sufficient in a catalytic amount, and is usually in the range of 0.1% by mass or more and 10% by mass or less with respect to the natural cellulose fiber (absolute dry basis) used as a raw material.

  In the oxidation treatment of the natural cellulose fiber, cooxidation with an oxidizing agent (for example, hypohalous acid or a salt thereof, hypohalous acid or a salt thereof, perhalogenic acid or a salt thereof, hydrogen peroxide, a perorganic acid, etc.) An agent (for example, an alkali metal bromide such as sodium bromide) is used in combination. As the oxidizing agent, alkali metal hypohalites such as sodium hypochlorite and sodium hypobromite are particularly preferable. The amount of the oxidizing agent used is usually in the range of about 1% by mass or more and about 100% by mass or less based on the natural cellulose fiber (absolute dry standard) used as a raw material. Moreover, the usage-amount of a co-oxidant is the range used normally as about 1 mass% or more and about 30 mass% or less with respect to the natural cellulose fiber (absolute dry reference | standard) used as a raw material.

  Further, in the oxidation treatment of the natural cellulose fiber, it is desirable that the pH of the reaction solution (the slurry) is maintained in the range of 9 or more and 12 or less from the viewpoint of allowing the oxidation reaction to proceed efficiently. The temperature of the oxidation treatment (the temperature of the slurry) is arbitrary at 1 ° C. or more and 50 ° C. or less, but the reaction is possible at room temperature, and temperature control is not particularly required. The reaction time is preferably 1 minute or more and 240 minutes or less.

  After the oxidation reaction step, before the refinement step, a purification step is performed to remove impurities other than reactant fibers and water contained in the slurry, such as unreacted oxidant and various by-products. preferable. Since the reaction fiber is not normally dispersed to the cellulose nanofiber unit at this stage, in the purification process, for example, a purification method in which water washing and filtration are repeated can be performed, and the purification apparatus used in that case is not particularly limited. . The purified oxidized cellulose fibers (or called carboxyl group-containing cellulose fibers) thus obtained are usually sent to the next step (miniaturization step) impregnated with an appropriate amount of water, but dried if necessary. It is good also as the processed fiber form and powder form.

  In the refinement step, the reaction product fibers that have undergone the purification step are dispersed in a solvent such as water, and the refinement process is performed. By passing through this refinement | miniaturization process, the cellulose nanofiber which has an average fiber diameter and carboxyl group content in the said range, respectively is obtained.

  In the above-mentioned micronization treatment, the solvent as the dispersion medium is usually preferably water, but water-soluble organic solvents (alcohols, ethers, ketones, etc.) may be used in addition to water depending on the purpose. Well, a mixture of these can also be used suitably. Examples of the disperser used in the miniaturization process include a disaggregator, a beater, a low pressure homogenizer, a high pressure homogenizer, a grinder, a cutter mill, a ball mill, a jet mill, a short screw extruder, a twin screw extruder, and an ultrasonic stirrer. A home juicer mixer or the like can be used. The solid content concentration of the oxidized cellulose fiber in the refining treatment is preferably 50% by mass or less. It is preferable that the solid content concentration is 50% by mass or less because the energy required for dispersion does not become excessively high.

  By such oxidation treatment and refinement treatment of natural cellulose fiber, the hydroxyl group at the C6 position of the cellulose constituent unit is selectively oxidized to a carboxyl group via an aldehyde group, and the average fiber diameter is preferably up to 200 nm or less. Finely divided highly crystalline cellulose fibers can be obtained. This highly crystalline cellulose fiber has a cellulose I-type crystal structure. This means that the cellulose nanofiber is a fiber obtained by surface-oxidizing and refining a naturally-derived cellulose solid raw material having an I-type crystal structure. That is, natural cellulose fibers have a high-order solid structure formed by a bundle of fine fibers called microfibrils produced in the process of biosynthesis, and a strong cohesive force between the microfibrils (between surfaces). The cellulose nanofibers can be obtained by weakening the hydrogen bond) by introducing the aldehyde group or carboxyl group by the oxidation treatment, and further through the refinement treatment. Then, by adjusting the conditions for the oxidation treatment, the carboxyl group content is increased or decreased within a predetermined range, the polarity is changed, the electrostatic repulsion of the carboxyl group or the refinement treatment, cellulose nanofibers The average fiber diameter, average fiber length, average aspect ratio, and the like can be controlled.

  Thus, the form of the cellulose nanofiber obtained is a state in which the cellulose nanofiber is dispersed in the dispersion. If necessary, it is a suspension in which the solid content concentration is adjusted (a visually transparent or opaque liquid) or a dried powder (however, a powder in which cellulose nanofibers are aggregated, which means cellulose particles. It is not a thing). In the case of suspension, only water may be used as a dispersion medium, and a mixed solvent of water and other organic solvents (for example, alcohols such as ethanol), surfactants, acids, bases, etc. is used. May be.

  In the resin composition of the present invention, the cellulose nanofibers thus obtained may be used, or cellulose nanofibers (hereinafter referred to as “hydrophobized cellulose nanofibers”) that have been made hydrophobic by modifying the carboxyl groups in the cellulose nanofibers with hydrocarbon groups. Also referred to as “cellulose nanofiber composite”). Hereinafter, the cellulose nanofiber composite will be described.

The cellulose nanofiber composite has a hydrocarbon group as a side chain of the cellulose main chain. The hydrocarbon group is bonded to the cellulose main chain through an amide bond. Examples of the hydrocarbon group include a hydrocarbon group having 1 carbon atom, and a saturated or unsaturated linear or branched hydrocarbon group having 2 to 30 carbon atoms. As will be described later, these hydrocarbon groups are derived from a primary amine or a secondary amine used as a raw material during the production of the cellulose nanofiber composite. Specific examples include the following hydrocarbon groups.
-A hydrocarbon group having 1 carbon atom: a methyl group.
-C2-C30 saturated, linear hydrocarbon group: ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group, decyl group, dodecyl group, octadecyl group, docosyl group An octacosanyl group.
-Unsaturated, linear hydrocarbon group having 2 to 30 carbon atoms: oleyl group, myristol group, palmitoleyl group, linoleyl group, linolenyl group, eicosanyl group.
A saturated branched hydrocarbon group having 2 to 30 carbon atoms: isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, t-pentyl group, isohexyl group, 2-hexyl group, Dimethylbutyl group, ethylbutyl group.

  The number of carbon atoms of the hydrocarbon group is arbitrarily selected depending on the combination with the thermosetting resin, but is preferably 1 or more, particularly 3 or more, particularly 10 or more, and 30 or less, particularly 20 or less, especially 18 or less. It is preferable that For example, it is preferably 1 or more and 30 or less, preferably 3 or more and 20 or less, and more preferably 10 or more and 18 or less. When the carbon number is in the above range, the cellulose nanofiber composite and the thermosetting resin are in a uniform mixed state, and good physical properties such as a low linear thermal expansion coefficient are obtained.

  In addition to the hydrocarbon group, a hydrocarbon group having a hydrophilic group such as hydroxyethyl group or hydroxypropyl group, a polyether chain such as ethylene glycol or propylene glycol, or a hydrocarbon chain having a polyester chain such as lactide or caprolactone. The group is also preferably used as a hydrocarbon group bonded through an amide bond in the cellulose nanofiber composite used in the present invention.

  In addition to the hydrocarbon group, alicyclic hydrocarbon groups such as cyclopentyl group and cyclohexyl group, and aromatic hydrocarbon groups such as benzyl group and phenyl group are also amides in the cellulose nanofiber composite used in the present invention. It is preferably used as a hydrocarbon group bonded through a bond.

The average binding amount of hydrocarbon groups in the cellulose nanofiber composite (average binding amount per unit mass of the cellulose nanofiber composite) is preferably 0.1 mmol / g or more, more preferably 0.5 mmol / g or more, And it is preferably 3 mmol / g or less, more preferably 2 mmol / g or less, and particularly preferably 1 mmol / g or less. More specifically, it is preferably 0.1 mmol / g or more and 3 mmol / g or less, more preferably 0.1 mmol / g or more and 2 mmol / g or less, and particularly preferably 0.5 mmol / g or more and 1 mmol / g or less. The average bond amount of the hydrocarbon group is calculated by the following formula. In the following formula, “carboxyl group content of cellulose nanofiber before introduction of hydrocarbon group” is measured by the above <Method for measuring carboxyl group content of cellulose nanofiber>, and “cellulose nanofiber after introduction of hydrocarbon group” The “carboxyl group content of the composite” is measured according to <Measurement method of carboxyl group content of cellulose nanofiber composite> described later.
Bond amount of hydrocarbon group (mmol / g) = carboxyl group content of cellulose nanofiber before introduction of hydrocarbon group (mmol / g) -carboxyl group content of cellulose nanofiber composite after introduction of hydrocarbon group (mmol) / G)

Moreover, the introduction rate of the hydrocarbon group to the cellulose nanofiber which is a raw material can be calculated from the average binding amount of the hydrocarbon group in the cellulose nanofiber composite according to the following formula.
Introduction rate of hydrocarbon groups (%) = {average amount of bonded hydrocarbon groups in the cellulose nanofiber composite (mmol / g) / carboxyl group content of cellulose nanofibers before introducing hydrocarbon groups (mmol / g) } × 100

  The cellulose nanofiber composite is preferably obtained by amidating the carboxyl group of a cellulose nanofiber having a carboxyl group. In this case, all of the carboxyl groups in the cellulose nanofiber composite may be amidated, or the carboxyl groups may remain without being amidated, and the carboxyl group may be a primary or secondary amine. It may remain in a salified state. The carboxyl group content of the cellulose nanofiber composite used in the present invention is preferably 0 mmol / g or more, more preferably 0.2 mmol / g or more, and preferably 2.9 mmol / g or less, more preferably 1 mmol / g. Hereinafter, it is particularly preferably 0.8 mmol / g or less. More specifically, it is preferably 0 mmol / g or more and 2.9 mmol / g or less, more preferably 0 mmol / g or more and 1 mmol / g or less, and particularly preferably 0.2 mmol / g or more and 0.8 mmol / g or less. The carboxyl group content of the cellulose nanofiber composite is measured as follows.

<Method for measuring carboxyl group content of cellulose nanofiber composite>
Take a cellulose nanofiber composite with a dry mass of 0.5 g in a 100 mL beaker, add ion-exchanged water or a mixed solvent of methanol / water = 2/1 to make a total of 55 mL, and add 5 mL of 0.01 M sodium chloride aqueous solution to it. A dispersion is prepared, and the dispersion is stirred until the cellulose nanofiber composite is sufficiently dispersed. 0.1M hydrochloric acid was added to this dispersion to adjust the pH to 2.5-3, and 0.05M sodium hydroxide aqueous solution was added using an automatic titrator (trade name “AUT-50” manufactured by Toa DKK Corporation). It is dropped into the dispersion under a condition of a waiting time of 60 seconds, and the conductivity and pH values are measured every minute, and the measurement is continued until pH 11 is obtained, thereby obtaining an conductivity curve. From this conductivity curve, the sodium hydroxide titration amount is obtained, and the carboxyl group content of the cellulose nanofiber composite is calculated by the following formula.
Carboxyl nanofiber composite carboxyl group content (mmol / g) = sodium hydroxide titration (ml) × sodium hydroxide aqueous solution concentration (0.05 M) / mass of fine cellulose fiber composite (0.5 g)

  In the cellulose nanofiber composite, preferably, a primary amine compound or a secondary amine compound having a hydrocarbon group (hereinafter, collectively referred to as “amine compound”) is added to the cellulose nanofiber. It can be obtained by bonding via a bond.

  The amine compound used constitutes a hydrocarbon group that is bonded via an amide bond or an ionic bond in the cellulose nanofiber composite that is the production object. Examples of the primary amine include monoalkylamines such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, octadecylamine, and oleylamine. Examples of the secondary amine include dialkylamines such as dimethylamine, diethylamine, dibutylamine, and dioctadecylamine.

  From the viewpoint of efficiently proceeding the amidation reaction between the amine compound and the cellulose nanofiber, a condensing agent may be added to the reaction system. The condensing agent is preferably added after the amine compound is added to the dispersion of cellulose nanofibers. As the condensing agent, a carbodiimide condensing agent, a triazine condensing agent, a phosphonium condensing agent, a benzotriazole condensing agent, an imidazole condensing agent, a polar group-containing halogenated carboxylic acid and the like can be used. Specifically, for example, DMT-MM (4- (4,4-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride), EDC (1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride), BOP (benzotriazol-1-yl-oxy-tris (dimethylamino) phosphonium hexafluorophosphate), benzotriazol-1-yl-oxy-tripyrrolidinophosphonium hexafluoro Examples thereof include phosphate, HBTU (o- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium hexafluorophosphate), 1,2-benzisothiazolin-3-one, and the like. .

  In the amidation reaction between an amine compound and cellulose nanofiber, the temperature of the reaction system (reaction temperature of the amidation reaction) is preferably 20 ° C. or higher and 80 ° C. or lower, and the reaction time is preferably 1 hour or longer and 24 hours or shorter. is there. After completion of the amidation reaction, the reaction system is washed and filtered according to a conventional method to remove impurities such as unreacted substances and various by-products. In this way, a cellulose nanofiber composite in which a hydrocarbon group is bonded to cellulose nanofiber via an amide bond is obtained. The cellulose nanofiber composite may be a swollen gel impregnated with a solvent (for example, acetone) used at the time of washing, or may be a dried fiber or powder.

  The resin composition of the present invention contains a thermosetting resin as a constituent component in addition to the above-described cellulose nanofiber or cellulose nanofiber composite. The thermosetting resin is present in the resin composition of the present invention in a state of being uniformly dispersed with the cellulose nanofiber or the cellulose nanofiber composite. There is no restriction | limiting in particular in the kind of thermosetting resin. Examples of the thermosetting resin include epoxy resin, phenol resin, melamine resin, urea resin, unsaturated polyester resin, and the like. These thermosetting resins can be used alone or in combination of two or more. Among these thermosetting resins, it is particularly preferable to use an epoxy resin because uniform dispersibility with cellulose nanofibers or cellulose nanofiber composites is further increased.

  When a cellulose nanofiber composite and a thermosetting resin are used as the constituent components of the resin composition of the present invention, a composition in which both of these components are uniformly dispersed can be obtained. On the other hand, when cellulose nanofibers and a thermosetting resin are used as the constituent components of the resin composition of the present invention, it is possible to use an alkyl imidazoline-based dispersant as the third component in combination with the cellulose nanofibers and the thermosetting resin. This is advantageous from the viewpoint of increasing uniform dispersion. In the following description, the resin composition containing a cellulose nanofiber composite and a thermosetting resin is also referred to as “resin composition A”. A resin composition containing cellulose nanofibers, a thermosetting resin, and an alkyl imidazoline-based dispersant is also referred to as “resin composition B”.

  As the alkyl imidazoline-based dispersant contained in the resin composition B, for example, a compound in which an alkyl group is bonded to at least one nitrogen atom of the 1-position or 3-position nitrogen atom in the imidazoline ring is used. Can do. Alternatively, those in which an alkyl group is bonded to at least one of the carbon atoms at the 2-position, 4-position or 5-position in the imidazoline ring can be used. As the alkyl group, for example, a saturated or unsaturated group having 2 or more, particularly 6 or more, especially 10 or more, and 30 or less, particularly 20 or less, particularly 18 or less can be used. Specifically, a saturated or unsaturated alkyl group having 2 to 30 carbon atoms, particularly 6 to 20 carbon atoms, particularly 10 to 18 carbon atoms is preferable. When two or more alkyl groups are bonded to the imidazoline ring, the type of each alkyl group may be the same or different. Particularly preferred alkyl imidazoline dispersants are compounds in which the same or different carbon atoms are bonded to the 1st and 3rd nitrogen atoms in the imidazoline ring.

  In the resin composition of the present invention, since the cellulose nanofiber or the cellulose nanofiber composite is uniformly dispersed in the resin composition, the cellulose nanofiber or the cellulose nanofiber composite occupies the resin composition. Even if the proportion of the body is not excessively increased, the characteristics of the resin composition can be improved. For example, when the resin composition of the present invention is the resin composition A, the content of the cellulose nanofiber composite in the resin composition A is 1% by mass or more, particularly 1.2% by mass or more, especially 1.5% by mass or more. Further, it is preferably 50% by mass or less, particularly 20% by mass or less, and particularly preferably 10% by mass or less. For example, the content of the cellulose nanofiber composite is preferably 1% by mass to 50% by mass, more preferably 1.2% by mass to 20% by mass, and more preferably 1.5% by mass to 10% by mass. More preferably, it is as follows.

  On the other hand, the content of the thermosetting resin in the resin composition A is 50% by mass or more, particularly preferably 80% by mass or more, particularly preferably 90% by mass or more, and 99% by mass or less, particularly 98.8% by mass or less. In particular, it is preferably 98.5% by mass or less. For example, the content of the thermosetting resin is preferably 50% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 98.8% by mass or less, and 90% by mass or more and 98.5% by mass or less. It is more preferable that

  When the resin composition of the present invention is the resin composition B, the content of cellulose nanofibers in the resin composition B is 1% by mass or more, particularly 1.2% by mass or more, especially 1.5% by mass or more. Further, it is preferably 50% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less. For example, the content of cellulose nanofibers is preferably 1% by mass or more and 50% by mass or less, more preferably 1.2% by mass or more and 20% by mass or less, and 1.5% by mass or more and 10% by mass or less. More preferably it is.

  On the other hand, the content of the thermosetting resin in the resin composition B is preferably 50% by mass or more, particularly preferably 80% by mass or more, particularly preferably 90% by mass or more, and 99% by mass or less, particularly 98.8% by mass or less. In particular, it is preferably 98.5% by mass or less. For example, the content of the thermosetting resin is preferably 50% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 98.8% by mass or less, and 90% by mass or more and 98.5% by mass or less. It is more preferable that

  The content of the alkylimidazoline-based dispersant in the resin composition B is 0.1% by mass or more, particularly 0.5% by mass or more, particularly 1% by mass or more, and preferably 50% by mass or less, particularly 20% by mass. Hereinafter, it is particularly preferably 5% by mass or less. For example, the content of the alkyl imidazoline-based dispersant is preferably 0.1% by mass or more and 50% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 5% by mass. More preferably, it is as follows.

  Since the resin composition of the present invention is in a state in which cellulose nanofibers or cellulose nanofiber composites are uniformly dispersed in the thermosetting resin, it combines with the characteristics inherent to the thermosetting resin, It has a linear thermal expansion coefficient. And since the thermosetting resin contained in this resin composition is a general purpose thing, it is economically advantageous. Therefore, this resin composition is suitably used as a raw material for, for example, an optical lens, a surface material of a solar cell, a substrate of a display element, etc., as a glass substitute material.

  Next, the suitable manufacturing method of the resin composition of this invention is demonstrated. When the resin composition to be manufactured is the above-described resin composition A, the resin composition A can be manufactured by the method A including the following steps (A1), (A2), and (A3). On the other hand, when the resin composition to be manufactured is the above-described resin composition B, the resin composition B can be manufactured by the method B including the following steps (B1), (B2), and (B3). it can.

[Method A]
(A1) A step of mixing a cellulose nanofiber composite in which hydrocarbon groups are bonded via an amide bond and a thermosetting resin prepolymer before thermosetting to obtain a mixture.
(A2) A step of forming the mixture into a predetermined shape to obtain a molded body.
(A3) A step of thermosetting the prepolymer in the molded body.

[Method B]
(B1) A step of obtaining a mixture by mixing cellulose nanofibers, a thermosetting resin prepolymer before thermosetting, and an alkylimidazoline-based dispersant.
(B2) A step of forming the mixture into a predetermined shape to obtain a molded body.
(B3) A step of thermosetting the prepolymer in the molded body.

  As the thermosetting resin prepolymer used in the step (A1) of the method A and the step (B1) of the method B, an appropriate one is selected according to the kind of the thermosetting resin. For example, when the thermosetting resin is an epoxy resin, examples of the thermosetting resin prepolymer include bisphenol A type, cresol novolac type, bisphenol A type, phenol novolac type, glycidyl ether type, alicyclic type, glycidyl amine type, A prepolymer such as a glycidyl ester type can be used.

  The thermosetting resin prepolymer in a state before curing is generally unnecessary for water but is soluble in an organic solvent. Accordingly, the cellulose nanofiber composite that has been hydrophobized by introduction of hydrocarbon groups has good compatibility with the thermosetting resin prepolymer. Therefore, the cellulose nanofiber composite and the thermosetting resin prepolymer can be uniformly mixed without using a third component such as a dispersant. On the other hand, cellulose nanofibers that are not hydrophobized before introduction of hydrocarbon groups may not be sufficiently compatible with the thermosetting resin prepolymer. Therefore, when the cellulose nanofiber and the thermosetting resin prepolymer are mixed, it is advantageous to use the above-described alkyl imidazoline dispersant together. This makes it possible to uniformly mix the cellulose nanofibers and the thermosetting resin prepolymer.

  In the case of mixing the thermosetting resin prepolymer and the cellulose nanofiber or the cellulose nanofiber composite in the step (A1) of the method A and the step (B1) of the method B, the cellulose nanofiber is mixed with a volatile solvent. It is preferable to mix in the state of an agglomerate containing or to mix the cellulose nanofiber composite in the agglomerate state containing a volatile solvent. By carrying out like this, the more uniform mixing with the thermosetting resin prepolymer which is a substance which has a property soluble in an organic solvent, and a cellulose nanofiber or a cellulose nanofiber composite body can be achieved.

  The aggregate of a cellulose nanofiber or a cellulose nanofiber composite can be prepared, for example, by the following method. First, it is preferable to use an organic solvent capable of dissolving the thermosetting resin prepolymer as the volatile solvent used to obtain the aggregate. There are various kinds of such organic solvents depending on the kind of the thermosetting resin prepolymer. Examples of common organic solvents include acetone, dimethylformamide, dimethyl sulfoxide, methanol, ethanol, N-methyl-2- Examples include pyrrolidone, acetonitrile, tetrahydrofuran, dioxane and the like. These volatile solvents are used to form aggregates of cellulose nanofibers or cellulose nanofiber composites. Formation of this aggregate can be performed as follows, for example. An excess amount of the volatile solvent (for example, acetone) serving as a poor dispersion medium for the cellulose nanofiber or the cellulose nanofiber composite is added to the cellulose nanofiber or the cellulose nanofiber composite dispersion (for example, the cellulose nanofiber aqueous dispersion). Mix to form aggregates. The aggregate can be obtained in the state of an aggregate containing a volatile solvent by removing the solvent by filtration or centrifugation.

  The relationship between the volatile solvent when forming the aggregate and the content of the cellulose nanofiber or the cellulose nanofiber composite is preferably as follows. That is, as described above, the aggregate is produced by filtration or centrifugation from a state containing a volatile solvent, and as a result, is obtained in a state swollen by a volatile solvent. From the viewpoint of physical properties when the resin composition is obtained, it is preferable that the volatile solvent is not completely removed, and the content of the volatile solvent at this time is preferably 50% or more, particularly preferably 80% or more.

  Through the above operation, a mixture containing the cellulose nanofiber composite and the thermosetting resin prepolymer (hereinafter, this mixture is referred to as the mixture A), or the cellulose nanofiber and the thermosetting resin prepolymer. , An alkyl imidazoline-based dispersant (hereinafter, this mixture is referred to as “mixture B”).

  The proportion of the cellulose nanofiber composite contained in the mixture A is preferably 1% by mass or more, particularly 1.2% by mass or more, particularly preferably 1.5% by mass or more, 50% by mass or less, particularly 20% by mass or less, In particular, it is preferably 10% by mass or less. For example, the ratio of the cellulose nanofiber composite is preferably 1% by mass or more and 50% by mass or less, more preferably 1.2% by mass or more and 20% by mass or less, and 1.5% by mass or more and 10% by mass or less. It is more preferable that On the other hand, the ratio of the thermosetting resin prepolymer contained in the mixture A is 50% by mass or more, particularly 80% by mass or more, particularly preferably 90% by mass or more, and 99% by mass or less, particularly 98.8% by mass or less. In particular, it is preferably 98.5% by mass or less. For example, the ratio of the thermosetting resin prepolymer is preferably 50% by mass to 99% by mass, more preferably 80% by mass to 98.8% by mass, and 90% by mass to 98.8% by mass. More preferably, it is as follows.

  The proportion of cellulose nanofibers contained in the mixture B is preferably 1% by mass or more, particularly 1.2% by mass or more, especially 1.5% by mass or more, 50% by mass or less, particularly 20% by mass or less, especially 10%. It is preferable that it is below mass%. For example, the proportion of cellulose nanofibers is preferably 1% by mass or more and 50% by mass or less, more preferably 1.2% by mass or more and 20% by mass or less, and more preferably 1.5% by mass or more and 10% by mass or less. More preferably. On the other hand, the ratio of the thermosetting resin prepolymer contained in the mixture B is preferably 50% by mass or more, particularly 80% by mass or more, particularly preferably 90% by mass or more, and 99% by mass or less, particularly 98.8% by mass or less. In particular, it is preferably 98.5% by mass or less. For example, the ratio of the thermosetting resin prepolymer is preferably 50% by mass to 99% by mass, more preferably 80% by mass to 98.8% by mass, and 90% by mass to 98.5% by mass. More preferably, it is as follows. Further, the proportion of the alkyl imidazoline dispersant contained in the mixture B is 0.1% by mass or more, particularly 0.5% by mass or more, particularly 1% by mass or more, preferably 50% by mass or less, particularly 20% by mass. Hereinafter, it is particularly preferably 5% by mass or less. For example, the proportion of the alkyl imidazoline-based dispersant is preferably 0.1% by mass or more and 50% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and 1% by mass or more and 5% by mass or less. It is more preferable that

  Next, a curing agent of a thermosetting resin prepolymer is added to the mixture A or the mixture B. As a hardening | curing agent, the thing similar to what has been used until now in the technical field of a thermosetting resin can be used. For example, polyamines such as linear polyamines such as triethylenetetramine, acid anhydrides, and the like can be used. Although the addition amount of a hardening | curing agent can be suitably selected according to a desired physical property, it can be set as the range of 0.1-20 mass% with respect to the said prepolymer.

  In the step (A1) or the step (B1), when the cellulose nanofiber or the cellulose nanofiber composite is mixed in the state of an aggregate, it is preferable to remove the volatile solvent used for the formation of the aggregate. . The removal of the volatile solvent is preferably performed at least before the step (A3) or (B3), and more preferably performed before the above-described curing agent is added to the mixture A or the mixture B. The removal of the volatile solvent can be performed, for example, by allowing the mixture A or the mixture B to stand under reduced pressure and volatilizing the volatile solvent.

  When the addition of the curing agent is completed, the step (A2) or the step (B2) is performed, and the mixture A or the mixture B is formed into a predetermined shape to obtain a formed body. The shape of the molded body is preferably the same as the shape of the target resin composition. For example, when it is desired to produce a plate-shaped resin composition, the shape of the molded body may be a plate corresponding to the shape. When forming a molded body from the mixture A or the mixture B, it is preferable to preheat the mixture A or the mixture B to semi-cure these mixtures. By performing such a semi-curing treatment, the shape retention of the molded body is enhanced and the thermosetting resin prepolymer can be successfully cured. The semi-curing treatment can be performed by, for example, hot pressing the mixture A or the mixture B formed into a predetermined shape. What is necessary is just to set the temperature and pressure of a hot press suitably according to the kind of thermosetting resin prepolymer, and the kind of hardening | curing agent. As an example, when a bisphenol A type prepolymer is used as the thermosetting resin prepolymer and triethylenetetramine is used as the curing agent, the temperature of the hot press can be set to 50 ° C. or higher and 300 ° C. or lower. The pressure can be set to 0.01 MPa or more and 1 MPa or less. The hot pressing time can be set to 1 minute or more and 60 minutes or less on condition that the temperature and pressure range are satisfied.

  When the molded body is obtained in this way, the thermosetting resin prepolymer contained in the molded body is cured in the step (A3) or the step (B3). Curing can generally be performed by heating. What is necessary is just to set a heating temperature suitably according to the kind of thermosetting resin prepolymer, and the kind of hardening | curing agent. As an example, when bisphenol A type prepolymer is used as the thermosetting resin prepolymer and triethylenetetramine is used as the curing agent, the heating temperature can be set to 100 ° C. or higher and 300 ° C. or lower. The heating time can be set to 1 minute or more and 600 minutes or less, provided that the temperature is within this temperature range.

  The target resin composition is obtained by the above steps. The resin composition thus obtained has a low linear thermal expansion coefficient as described above.

Regarding the above-described embodiment of the present invention, the following additional notes are disclosed.
<1>
A resin composition containing cellulose nanofibers and a thermosetting resin,
The resin composition which is a cellulose nanofiber composite_body | complex in which the said cellulose nanofiber has a hydrocarbon group couple | bonded through an amide bond.

<2>
A resin composition containing cellulose nanofibers and a thermosetting resin,
Furthermore, the resin composition containing the alkyl imidazoline type dispersing agent.

<3>
The resin composition according to <1>, wherein the content of the cellulose nanofiber composite is 1% by mass or more and 50% by mass or less.
<4>
The content of the cellulose nanofiber composite is preferably 1% by mass or more, particularly 1.2% by mass or more, particularly 1.5% by mass or more, and 50% by mass or less, particularly 20% by mass or less, especially 10%. It is preferable that it is below mass%. For example, the content of the cellulose nanofiber composite is preferably 1% by mass to 50% by mass, more preferably 1.2% by mass to 20% by mass, and more preferably 1.5% by mass to 10% by mass. The resin composition according to <1>, which is more preferably as follows.
<5>
<1> or <3>, wherein the hydrocarbon group is a hydrocarbon group having 1 carbon atom, or a saturated or unsaturated linear or branched hydrocarbon group having 2 to 30 carbon atoms. The resin composition as described.
<6>
The number of carbon atoms of the hydrocarbon group is preferably 1 or more, particularly 3 or more, particularly 10 or more, and preferably 30 or less, particularly 20 or less, particularly 18 or less. For example, the resin composition according to <5>, which is preferably 1 or more and 30 or less, preferably 3 or more and 20 or less, and more preferably 10 or more and 18 or less.
<7>
The resin composition according to <2>, wherein a content of the alkyl imidazoline-based dispersant is 10% by mass or more and 500% by mass or less with respect to the cellulose nanofiber.

<8>
The resin composition according to any one of <1> to <7>, wherein the thermosetting resin is an epoxy resin.
<9>
It is a manufacturing method of the resin composition as described in <1>,
(A1) A cellulose nanofiber composite formed by bonding a hydrocarbon group via an amide bond and a thermosetting resin prepolymer before thermosetting are mixed to obtain a mixture,
(A2) Molding the mixture into a predetermined shape to obtain a molded body,
(A3) The manufacturing method of the resin composition which has the process of thermosetting the said prepolymer in the said molded object.
<10>
It is a manufacturing method of the resin composition as described in <2>,
(B1) Cellulose nanofibers, a thermosetting resin prepolymer before thermosetting, and an alkylimidazoline-based dispersant are mixed to obtain a mixture,
(B2) Molding the mixture into a predetermined shape to obtain a molded body,
(B3) The manufacturing method of the resin composition which has the process of thermosetting the said prepolymer in the said molded object.
<11>
The cellulose nanofiber composite in the step (A1) is an aggregate containing a volatile solvent, or the cellulose nanofiber in the step (B1) is an aggregate containing a volatile solvent,
The method for producing a resin composition according to <9> or <10>, further comprising a step of removing the volatile solvent before the step (A3) or the step (B3).

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” and “part” mean “% by mass” and “part by mass”, respectively. Of the following Examples 1 to 7, Examples 1 to 5 are reference examples and are outside the scope of the present invention.

[Example 1]
(1) Manufacture of Cellulose Nanofiber Composite and Aggregate Containing the Composite Conifer bleached kraft pulp (manufacturer: Fletcher Challenge Canada, trade name “Machenzie”, CSF 650 ml) was used as natural cellulose fiber. As TEMPO, a commercial product (manufacturer: ALDRICH, Free radical, 98%) was used. A commercial product (manufacturer: Wako Pure Chemical Industries, Ltd.) was used as sodium hypochlorite. A commercial product (manufacturer: Wako Pure Chemical Industries, Ltd.) was used as sodium bromide. First, 100 g of bleached kraft pulp fiber of coniferous trees was sufficiently stirred with 9900 g of ion-exchanged water, and then TEMPO 1.25%, sodium bromide 12.5%, sodium hypochlorite 28.4% with respect to 100 g of pulp mass. Were added in this order. Using a pH stat, 0.5M sodium hydroxide was added dropwise to maintain the pH at 10.5, and an oxidation reaction was performed. After the oxidation was performed for 120 minutes, dropping was stopped to obtain a carboxyl group-containing cellulose fiber. The carboxyl group-containing cellulose fiber was sufficiently washed with ion-exchanged water, and then dehydrated. Thereafter, 100 g of the obtained carboxyl group-containing cellulose fiber was dispersed in 9900 g of ion-exchanged water and treated twice using a high-pressure homogenizer (HJP-25005, manufactured by Sugino Machine Co., Ltd.) under a discharge pressure of 245 MPa. . By the operation, the fiber was refined to obtain a dispersion of cellulose nanofibers. The solid content concentration of the dispersion was 1.0%. This cellulose nanofiber had an average fiber diameter of 3.3 nm and a carboxyl group content of 1.2 mmol / g.

  Add 4085 g of the cellulose nanofiber dispersion (solid content concentration 1.3%) and 4085 g of ion-exchanged water to a beaker to obtain a cellulose nanofiber dispersion with a solid content concentration of 0.5%. This dispersion is a mechanical stirrer. For 3 hours at room temperature. Subsequently, 245 g of a 1M hydrochloric acid aqueous solution was charged into the cellulose nanofiber dispersion and reacted overnight at room temperature. After completion of the reaction, the solution was reprecipitated with acetone, filtered, and then washed with acetone / ion exchange water to remove hydrochloric acid and salts. Finally, acetone was added and filtered to obtain cellulose nanofiber aggregates (solid content concentration 5.0%) in a state where cellulose nanofibers were swollen with acetone.

  Into a four-necked round bottom flask equipped with a mechanical stirrer and a reflux tube was charged 488.80 g of the cellulose nanofiber aggregate (solid content adjusted from 5.0% to 4.4%), and t-butyl alcohol. 4800 g was added to obtain a cellulose nanofiber aggregate dispersion with a solid content concentration of 0.5%, and the mixture was stirred at room temperature for 1 hour. Subsequently, 17.50 g of octadecylamine (corresponding to 2 mol of amine group with respect to 1 mol of carboxyl group of cellulose nanofiber) and 17.97 g of DMT-MM were charged, dissolution was confirmed, and reaction was performed at 55 ° C. for 6 hours. After completion of the reaction, the mixture was filtered and then washed with methanol / ion exchange water to remove unreacted octadecylamine and DMT-MM. Finally, acetone was added and filtered to prepare a cellulose nanofiber composite in which octadecyl group was bonded to cellulose nanofiber through an amide bond. This cellulose nanofiber composite was swollen by acetone used for filtration to form an aggregate.

(2) Preparation of mixture with thermosetting resin prepolymer Aggregates (solid content: 0.48 g) of cellulose nanofiber composite obtained in (1) and bisphenol A type prepolymer (DIC Corporation) 850-CRP) was mixed with 30 g using a stirrer (rotating / revolving vacuum mixer ARV-310, manufactured by Shinkey Co., Ltd., rotation speed 2000 rpm, time 2 minutes) to obtain a mixture. This mixture was allowed to stand for 1 day under a reduced pressure of 50 mmHg to volatilize and remove acetone from the mixture. After acetone is removed, triethylenetetramine, which is a prepolymer curing agent, is added to the mixture, and again a stirrer (rotating / revolving vacuum mixer ARV-310, Sinky Corp., rotation speed 2000 rpm, pressure 0.3 kPa, Time 2 minutes). The addition amount was 10% with respect to the prepolymer.

(3) Manufacture of molded body The mixture obtained in (2) was semi-cured by preheating with a hot press. A metal frame having a thickness of 0.45 mm and an inner diameter of 10 cm was sandwiched between stainless steel metal plates, and the mixture was poured into the metal frame for hot pressing. The conditions for hot pressing were a temperature of 70 ° C., a pressure of 0.1 MPa, and a time of 30 minutes. A film-like molded body was obtained by this hot pressing.

(4) Prepolymer Curing The film-like molded product obtained in (3) was heated in a thermostat bath at 130 ° C. for 5 hours to cure the prepolymer. This obtained the thermosetting resin composition which consists of a film of thickness 0.45mm.

[Example 2]
In this example, a cellulose nanofiber composite having an octyl group bonded through an amide group was produced. That is, in Example 1, octadecylamine was replaced with 8.4 g of octylamine (corresponding to 2 mol of amine group with respect to 1 mol of carboxyl group of cellulose nanofiber). Except this, it carried out similarly to Example 1, and obtained the thermosetting resin composition.

Example 3
In this example, the blending amount of the cellulose nanofiber composite in the step (2) in Example 1 was set to the values shown in Table 1 below. Except this, it carried out similarly to Example 1, and obtained the thermosetting resin composition.

Example 4
The cellulose nanofiber composite in Example 1 was mixed with isopropanol to obtain a cellulose nanofiber composite dispersion having a solid content concentration of 0.5% by mass. Next, 200 g of the cellulose nanofiber composite dispersion (solid content: 1.0 g) and 4.0 g of epoxy resin prepolymer (PCE-750 Pernox, manufactured by Co., Ltd.) were mixed. The mixed solution was poured into a polystyrene petri dish and allowed to stand for 5 days in an environment of 23 ° C. and 50% RH, whereby isopropanol was volatilized to obtain a cellulose nanofiber complex and a prepolymer complex. The composite was hot-pressed and cured in the same manner as in Example 1 to obtain a thermosetting resin composition.

Example 5
The cellulose nanofiber composite in Example 2 was mixed with ion exchange water to obtain a cellulose nanofiber composite dispersion having a solid content of 0.5% by mass. Subsequently, 200 g of this cellulose nanofiber composite dispersion (solid content: 1.0 g) and 4.0 g of epoxy resin prepolymer (PCE-750, Pernox Co., Ltd.) were mixed. The mixed solution was poured into a polystyrene petri dish and allowed to stand in an environment of 23 ° C. and 50% RH for 5 days to volatilize ion-exchanged water, thereby obtaining a composite of cellulose nanofiber composite and prepolymer. The composite was hot-pressed and cured in the same manner as in Example 2 to obtain a thermosetting resin composition.

[Examples 6 and 7]
In this example, instead of using the aggregate of the cellulose nanofiber composite in Example 1, the aggregate of the cellulose nanofiber obtained in the process of producing the aggregate of the cellulose nanofiber composite was used. The blending amount of the cellulose nanofiber aggregates was as shown in Table 1. In addition, homogenol L-95 (manufactured by Kao Corporation) was used as the alkylimidazoline-based dispersant in the amount shown in the same table. Except these, it carried out similarly to Example 1, and obtained the thermosetting resin composition.

[Comparative Example 1]
This comparative example is an example in which the aggregate of the cellulose nanofiber composite was not used in Example 1. Except for this, a thermosetting resin was obtained in the same manner as in Example 1.

[Comparative Example 2]
This comparative example is an example in which no alkyl imidazoline dispersant was used in Example 6. Except this, it carried out similarly to Example 1, and obtained the thermosetting resin composition.

[Comparative Example 3]
This comparative example is an example in which the aggregate of the cellulose nanofiber composite was not used in Example 4. Except this, a thermosetting resin was obtained in the same manner as in Example 4.

[Evaluation]
About the resin composition and resin obtained by each Example and each comparative example, the linear thermal expansion coefficient was measured by the method described below. The results are shown in Table 1 below. Moreover, about the resin composition, the ratio of the cellulose nanofiber or the cellulose nanofiber complex contained in it or the cellulose nanofiber was derived from the blending amount of each material, and these results are shown in Table 1 below.

(Measurement of linear thermal expansion coefficient)
The linear thermal expansion coefficient was measured using a tensile mode of a thermomechanical analyzer TMA / SS6100 (Seiko Instruments Co., Ltd.). The temperature was increased from 0 ° C. to 300 ° C. at a rate of temperature increase of 5 ° C./min, a load of 7 mN, under a nitrogen atmosphere, and the linear thermal expansion coefficient was calculated from the sample elongation from 20 ° C. to 200 ° C.

  As is apparent from the results shown in Table 1, Examples 1 to 3 containing a cellulose nanofiber composite and Examples 6 and 7 containing a cellulose nanofiber and an alkylimidazoline-based dispersant are Comparative Examples 1 containing no cellulose nanofiber. Compared to Comparative Example 2 that does not contain any alkyl imidazoline-based dispersant, it exhibits a low linear thermal expansion coefficient. This is considered to be because cellulose nanofibers were uniformly dispersed in the thermosetting resin by using a cellulose nanofiber composite or an alkylimidazoline-based dispersant. In particular, in Examples 1 and 3 in which the hydrocarbon group had 18 carbon atoms, the linear thermal expansion coefficient was remarkably reduced to 60 ppm / K or less. Examples 4 and 5 are resin compositions having a cellulose nanofiber composite content of 20%, but the linear thermal expansion coefficient was significantly reduced to 50 ppm / K or less.

Claims (6)

A cured product of a resin composition containing cellulose nanofibers and a thermosetting resin,
Further seen containing an alkyl imidazoline dispersant,
The thermosetting resin is an epoxy resin;
Hardened | cured material of the resin composition whose average fiber diameters of the said cellulose nanofiber are 1 nm or more and 200 nm or less . 2. The cured product of the resin composition according to claim 1, wherein the content of the alkyl imidazoline-based dispersant is 10% by mass or more and 500% by mass or less with respect to the cellulose nanofiber. The alkyl imidazoline-based dispersant is one in which an alkyl group is bonded to at least one nitrogen atom of the 1-position or 3-position nitrogen atom in the imidazoline ring, or the 2-position, 4-position in the imidazoline ring. Or the hardened | cured material of the resin composition of Claim 1 or 2 which is what the alkyl group has couple | bonded with the carbon atom of at least one place of the 5-position carbon atoms. The content of the cellulose nanofibers in the resin composition is 1% by mass or more and 20% by mass or less, and the content of the alkylimidazoline-based dispersant is 0.1% by mass or more and 20% by mass or less. A cured product of the resin composition according to any one of 3 . A method for producing a cured product of the resin composition according to claim 1,
(B1) Cellulose nanofibers, a thermosetting resin prepolymer before thermosetting, and an alkylimidazoline-based dispersant are mixed to obtain a mixture,
(B2) Molding the mixture into a predetermined shape to obtain a molded body,
(B3) the prepolymer in the shaped body have a step of thermal curing,
The thermosetting resin is an epoxy resin;
Method of manufacturing a cured product of the average fiber diameter of the resin composition Ru der than 200nm or less 1nm of the cellulose nanofiber. ( B1) The cellulose nanofiber in the step is an aggregate containing a volatile solvent,
( B3) The manufacturing method of the hardened | cured material of the resin composition of Claim 5 which further has the process of removing the said volatile solvent before a process.