WO2023013514A1

WO2023013514A1 - Cellulose-containing resin composition, filament for 3d printers, and method for preparing cellulose-containing resin composition

Info

Publication number: WO2023013514A1
Application number: PCT/JP2022/029071
Authority: WO
Inventors: 憲治青木; 康太井出; 宏文小倉; 剛英渡邉
Original assignee: 国立大学法人静岡大学; 東洋レヂン株式会社
Priority date: 2021-08-06
Filing date: 2022-07-28
Publication date: 2023-02-09

Abstract

Provided are: a cellulose-containing resin composition that despite containing a crystalline resin, exhibits good moldability in various types of 3D printers; a filament for 3D printers; and a method for preparing a cellulose-containing resin composition. The cellulose-containing resin composition includes a crystalline resin and a cellulose composite in which a nonpolar polymer is bound to a hydroxyl group of cellulose via a reactive group capable of reacting with the hydroxyl group.

Description

Cellulose-containing resin composition, 3D printer filament, and method for producing cellulose-containing resin composition

The present invention relates to a cellulose-containing resin composition, a 3D printer filament, and a method for producing a cellulose-containing resin composition. In particular, the present invention relates to a cellulose-containing resin composition that can be used in a hot melt deposition method (FDM method) despite containing a crystalline resin, a filament for 3D printers, and a method for producing a cellulose-containing resin composition. .

From the perspective of bioeconomy, attempts are being made to use biomass for olefin resins in various industrial fields (for example, the automobile field, etc.). Specifically, techniques for compounding cellulose such as cellulose fibers and cellulose nanofibers (CNF) with olefin resins and the like are being studied.

Cellulose and cellulose nanofibers (CNF) are made from pulp, etc., and are obtained through mechanical fibrillation in water, so they exist in an aqueous dispersion or state containing a large amount of water. When compounding cellulose or CNF with a resin, it is first necessary to remove moisture from the cellulose or CNF. In this case, if the cellulose or CNF is subjected to a normal heating and drying treatment, the cellulose or CNF becomes a firm aggregate due to the hydrogen bonding of the cellulose or CNF. Even if these aggregates are pulverized, the originally expected effects of cellulose and CNF are not exhibited. Therefore, various methods for extracting CNF capable of suppressing aggregation of cellulose and CNF and methods for dispersing cellulose in resin for the purpose of suppressing aggregation have been investigated.

Here, when cellulose and resin are combined, if the resin is non-polar, it is difficult to combine due to the incompatibility between the resin and the polar cellulose. It is also difficult to suppress aggregation of cellulose within the composite material. Therefore, for example, a technique of adding a compatibilizer (dispersant) to composite cellulose and resin has been proposed.

On the other hand, in recent years, three-dimensional structure modeling technology using 3D printers has been developed. For example, the price of 3D printers of the material extrusion deposition type (FDM method) that deposits resin filaments by thermal melting is progressing. . Therefore, not only the manufacturing industry, but also small businesses, technical high schools, and individuals, etc., can manufacture 3D objects without using molds, and 3D objects with shapes that are difficult to mold with molds. manufacturing is possible. Attempts have been made to add cellulose or cellulose nanofibers to the resin used for modeling the three-dimensional structure by this 3D printer to improve the strength and the like of the structure.

For example, modeling materials for 3D printers, which are mainly composed of resin components consisting of (A) nanofibers, (B) dispersants, and (C) thermoplastic resins or photocurable resins, are known. (See Patent Document 1, for example). According to the modeling material described in Patent Document 1, it is possible to obtain a three-dimensional model that has improved strength and elastic modulus, can reproduce surface conditions with fine patterns, has excellent surface smoothness, and is also excellent in transparency and dyeability. .

JP 2017-170881 A US2013/0224423 A1

However, in the modeling material described in Patent Document 1, when dispersing cellulose in resin, the addition of a dispersing agent cannot be omitted. Time and cost will increase. In addition, although a method of hydrophobizing the surface of cellulose has been conventionally used, it is assumed that such a method cannot omit purification treatment, and it may be difficult to maintain the properties of cellulose by various treatments. The time and effort and cost of

Furthermore, while polylactic acid, ABS resin, etc. are mainly used as resins used in conventional 3D printers, crystalline resins are practically not used. This is because, in the case of a method that melts and cools the resin like the FDM method, the crystalline resin (for example, polypropylene) shrinks thermally when cooling, so the molding property cannot be maintained. This is because it is difficult to use (see, for example, paragraph [0035] of Patent Document 2).

Therefore, an object of the present invention is to provide a cellulose-containing resin composition, a filament for 3D printers, and a cellulose-containing resin that exhibit good molding properties in various types of 3D printers including the FDM method despite containing a crystalline resin. An object of the present invention is to provide a method for producing a composition.

In order to achieve the above object, the present invention provides a cellulose-containing resin containing a crystalline resin and a cellulose composite comprising a hydroxyl group of cellulose and a non-polar polymer bonded via a reactive group capable of reacting with the hydroxyl group. A composition is provided.

Also, in order to achieve the above object, the present invention provides a 3D printer filament containing the cellulose-containing resin composition described above.

Furthermore, in order to achieve the above object, the present invention includes an aqueous emulsion of a cellulose having hydroxyl groups and containing moisture, and a polymer having a reactive group capable of reacting with the hydroxyl groups and having a nonpolar polymer molecular chain. a step of combining a hydroxyl group and a reactive group in an aqueous emulsion to obtain a cellulose composite; and a step of kneading the cellulose composite and a crystalline resin. A manufacturing method is provided. Further, in order to achieve the above object, the present invention provides a cellulose-containing composite comprising a crystalline resin and a cellulose composite in which a non-polar polymer is bonded to the hydroxyl groups of cellulose via a reactive group capable of reacting with the hydroxyl groups. A method for improving the formability of a 3D printer using a 3D printer filament constructed using a resin composition is provided.

According to the cellulose-containing resin composition, the filament for 3D printer, and the method for producing the cellulose-containing resin composition according to the present invention, although it contains a crystalline resin, it is suitable for various types of 3D printers including the FDM type. It is possible to provide a cellulose-containing resin composition exhibiting moldability, a filament for 3D printers, and a method for producing a cellulose-containing resin composition.

It is a figure which shows the relationship between the CNF density|concentration in a cellulose containing resin composition, and the number of lamination|stacking.

[Embodiment]
Until now, it was sometimes recognized that it was necessary to make the hydroxyl groups of cellulose reactive when reacting and bonding predetermined reactive groups to the hydroxyl groups of cellulose or cellulose nanofibers (CNF). However, the present inventor believes that if a reactive group is reactive with a hydroxyl group, for example, the contact probability between the hydroxyl group and the reactive group should be improved (for example, a reactive group should be added to the main chain of a predetermined molecular weight or more. By using a polymer having a side chain, the side chain also moves due to the movement of the main chain, etc., and the contact probability with the hydroxyl group of cellulose is improved, and the hydroxyl group and / or reactive group easily collide with each other. With the idea that it is possible to form a predetermined bond without providing a treatment or process for activating the hydroxyl group by reacting the hydroxyl group and the reactive group in, etc., an aqueous cellulose dispersion and maleic anhydride-modified polypropylene ( MAPP) emulsion was used to attempt to introduce MAPP into cellulose. As a result, it was surprisingly found that an ester bond easily occurs between the hydroxyl group of cellulose and the succinic anhydride group of MAPP by heating at a relatively low temperature.

Furthermore, the inventors of the present invention have discovered that by simply adding a very small amount of a cellulose composite synthesized based on such findings to a thermoplastic resin, volumetric shrinkage can be greatly suppressed even if the thermoplastic resin is cooled after being heated and melted. . The present invention is based on these findings and discoveries.

<Overview of Cellulose Composite>
A cellulose composite according to an embodiment of the present invention is formed by binding a non-polar polymer to a hydroxyl group of cellulose via a reactive group. In the cellulose composite according to the present embodiment, the cellulose surface has a low molecular weight (for example, an organic compound having a weight average molecular weight of about 1,000 or less. 200) except for MA oligomers.) Unlike the conventional treatment of hydrophobization using an organic compound, a nonpolar polymer is bound to cellulose as a so-called "compatibility group" (conceptually , directly bonding a high molecular weight compatibilizer to cellulose). This eliminates the need to add a compatibilizer (dispersant) when dispersing the cellulose composite according to the present embodiment in a predetermined non-polar resin.

In addition, the cellulose composite is a polymer trapped in the cellulose composite (that is, a polymer containing the reactive group and the nonpolar polymer. In other words, the molecular chain is the nonpolar polymer. and a polymer having a reactive group attached to the molecular chain.). Here, the term “captured” means that the polymer is fixed to the cellulose composite to such an extent that the polymer does not easily detach from the cellulose composite, is entangled with the cellulose composite, or is at least one of the cellulose composite. It means at least one of coating the part. Since the cellulose composite contains a polymer trapped in the cellulose composite, the trapped polymer also exhibits the function as a compatibilizer while being trapped, so cellulose dispersion in a nonpolar resin becomes easier.

In the present embodiment, the term "molecular chain" refers to a polymer, an oligomer molecule, or a polymer composed of structural units that are linearly or branchedly connected between terminal groups, branch points, or boundary structural units unique to polymers. Or refers to a configuration including all or part of a block.

<Overview of cellulose-containing resin composition>
A cellulose-containing resin composition according to an embodiment of the present invention comprises a crystalline resin and a cellulose composite in which a non-polar polymer is bonded to hydroxyl groups of cellulose via reactive groups capable of reacting with hydroxyl groups. composed of A filament for a 3D printer is produced by filamentizing the cellulose-containing resin composition according to the present embodiment. In addition, the content of cellulose in the cellulose-containing resin composition is adjusted to a concentration within a range in which aggregation of cellulose can be suppressed in the cellulose-containing resin composition and a network structure of cellulose is formed. By using this filament for 3D printers, the molding properties of 3D printers are improved.

<Details of cellulose composite>
A cellulose composite is a composite formed by binding a nonpolar polymer to cellulose via a predetermined bond formed by reacting a predetermined reactive group with a hydroxyl group of cellulose. The cellulose composite can be obtained in powder form. As cellulose, cellulose fibers, cellulose nanofibers (CNF), and/or microfibrillated cellulose (MFC) can be used.

(cellulose fiber)
Various cellulose fibers can be used as long as the cellulose fibers have hydroxyl groups on the surface. Cellulose fibers include plant-derived cellulose fibers, animal-derived cellulose fibers (e.g., cellulose fibers isolated from sea squirts, seaweed, etc.), microorganism-derived cellulose fibers (e.g., cellulose fibers produced by acetic acid bacteria, etc.), and the like. One or more cellulose fibers can be selected and used from among them. From the viewpoints of practicality, price, and/or availability, it is preferable to use plant-derived cellulose fibers as the cellulose fibers.

Examples of raw materials for plant-derived cellulose fibers include plant fibers such as pulp obtained from natural plant raw materials such as wood, bamboo, hemp, jute, kenaf, cotton, beets, agricultural waste, and cloth. In addition, waste papers such as waste newspapers, waste cardboards, waste magazines, waste copy papers, etc., can also be mentioned as raw materials for cellulose fibers. Examples of wood include cedar, cypress, eucalyptus, and acacia. Pulp or fibrillated cellulose obtained by fibrillating pulp can also be used as a raw material for cellulose fibers. The raw materials for the cellulose fiber can be used singly or in combination of two or more.

When using plant-derived raw materials (that is, plant fibers) as raw materials for cellulose fibers, it is preferable to remove lignin in the plant fibers. That is, plant fibers have a structure in which lignin and hemicellulose are filled between cellulose fibers, and hemicellulose and/or lignin cover a part or all of the bundles of cellulose microfibrils. It has a structure in which cellulose microfibrils and/or bundles of cellulose microfibrils are covered with hemicellulose, and the hemicellulose is further covered with lignin. As a result, the plant fibers are formed in a state in which the cellulose fibers are strongly bonded together by lignin. Therefore, from the viewpoint of suppressing aggregation of cellulose fibers in plant fibers, it is preferable to remove lignin in plant fibers.

For example, the amount of lignin in the raw material may be adjusted by subjecting the cellulose fiber raw material to treatments such as delignification and bleaching, if necessary. In the present embodiment, the lignin content in the cellulose fiber raw material is not particularly limited, but from the viewpoint of suppressing aggregation of cellulose fibers, the lignin content in the plant fiber-containing material is about 40% by mass or less, and 10% by mass. About mass % or less is preferable. Also, the lower limit of lignin is not particularly limited, and the closer to 0% by mass, the better. In addition, lignin content can be measured by the Klason method.

Also, the average fiber length of cellulose fibers is not particularly limited. However, the longer the average fiber length of the cellulose fibers, the more the effect of improving the properties can be expected. Incidentally, for example, when CNF obtained by chemical fibrillation (for example, TEMPO-oxidized CNF) is used as the cellulose fiber, the aspect ratio of this CNF is about 1,000 (that is, the width of the cellulose fiber is 3 nm to 5 nm. , fiber length is about 3 μm).

(cellulose nanofiber)
Cellulose nanofibers (CNF) are nanofibers obtained by refining (fibrillating) a material containing cellulose fibers (for example, the raw material for the cellulose fibers) to a nanosize level. Various CNFs can be used as the CNFs according to the present embodiment as long as they have hydroxyl groups on the surface.

In addition, there is no particular limitation on the method for producing CNF, and various conventionally known production methods can be adopted. For example, CNF can be prepared by defibrating a raw material of cellulose fibers (for example, pulp or the like). In the fibrillation method, first, an aqueous suspension or slurry of cellulose fibers is prepared, and the prepared aqueous suspension or slurry is processed using a refiner, a high-pressure homogenizer, a grinder, a kneader (extruder), a bead mill, or the like. CNF can be prepared by defibrating the cellulose fibers by mechanical grinding or the like.

There is no particular limitation on the average value of the CNF fiber diameter (average fiber diameter). The average fiber diameter of CNF may be 4 nm or more and about 200 nm or less, may be about 150 nm or less, may be about 100 nm or less, or may be about 50 nm or less. In addition, the average value of the fiber length of CNF (average fiber length) may be about 3 μm or more, may be about 5 μm or more, may be about 100 μm or less, or may be about 500 μm or less. The average value of the fiber diameter and the average value of the fiber length of the CNF are, for example, a predetermined number or more (for example, 50 or more) of CNF observed in a predetermined field of view of an electron microscope. It may be a calculated average value.

Further, the specific surface area of CNF is preferably 70 m ² /g or more, more preferably 100 m ² /g or more, preferably about 300 m ² /g or less, more preferably about 250 m ² /g or less, and about 200 m ² /g or less. is more preferable, and about 150 m ² /g or less is most preferable. For example, the specific surface area of carboxymethyl cellulose (CMC, chemically treated CNF), which is CNF, is about 300 m ² /g. The specific surface area can be measured by the BET method.

(microfibrillated cellulose)
Microfibrillated cellulose (MFC) is a fiber with a larger average fiber diameter than CNF. Microfibrillated cellulose (MFC) is obtained by defibrating a material containing cellulose fibers (for example, the raw material for the cellulose fibers described above). Various types of MFC can be used as the MFC according to the present embodiment as long as it has hydroxyl groups on its surface.

In addition, there is no particular limitation on the manufacturing method of MFC, and various conventionally known manufacturing methods can be adopted. For example, MFC can be prepared by beating or fibrillating raw materials of cellulose fibers (for example, pulp).

There is no particular limitation on the average value of the MFC fiber diameter (average fiber diameter). The average fiber diameter of the MFC may be, for example, about 0.3 μm or more, about 1 μm or more, about 5 μm or more, about 8 μm or more, or about 50 μm or less. may be about 40 μm or less, and may be about 30 μm or less. In addition, the average value of the fiber length of MFC (average fiber length) may be about 500 μm or more, may be about 700 μm or more, may be about 800 μm or more, may be about 3 mm or less, and may be 2 mm or less. It may be to some extent. The average value of the fiber diameter and the average value of the fiber length of MFC are, for example, the fiber diameter and fiber length of a predetermined number or more (for example, 50 or more) of MFC observed in a predetermined field of view of an electron microscope or an optical microscope. It may be an average value calculated by measurement.

[High molecular]
A polymer according to the present embodiment (that is, a polymer consisting of a predetermined molecular chain having a reactive group) has a reactive group capable of reacting with a hydroxyl group, and the molecular chain is substantially nonpolar or hydrophobic. It is a polymer. This reactive group reacts with the hydroxyl group of cellulose to form a predetermined bond, thereby bonding the molecular chain of the polymer to the cellulose. In the present embodiment, the polymer only needs to have a reactive group in its molecular chain, and the chain length of the reactive group need not be controlled. In addition, other structural units may be partly contained in the molecular chain as long as they do not inhibit the reaction between the reactive group and the hydroxyl group. Furthermore, the non-polar macromolecules of the molecular chain may have other groups different from the reactive groups. In addition, the reactive groups that react with the hydroxyl groups of cellulose may be at least a part of the reactive groups in the polymer, and it is not necessary that all the reactive groups and the hydroxyl groups of cellulose form bonds. .

(reactive group)
Reactive groups include at least one group selected from the group consisting of succinic anhydride groups, carbonyl groups (eg, methoxycarbonyl groups), and carboxyl groups. Therefore, the bond formed by the reaction between the hydroxyl group of cellulose and the reactive group is an ester bond. Also, the bond formed by reacting with a hydroxyl group may be an amide bond, an ether bond, or a urethane bond.

(Molecular chain: non-polar polymer)
A non-polar polymer is a polymer substance that does not have a permanent dipole. is also a non-polar polymer. Examples of nonpolar polymers include polyethylene resins, polypropylene resins, tetrafluoroethylene resins, and the like.

In the present embodiment, the non-polar polymer that is the molecular chain includes substantially non-polar or hydrophobic olefin resins. Olefin resins include polypropylene, polyethylene, ethylene/vinyl acetate copolymer resin, vinyl chloride resin, styrene resin, (meth)acrylic resin, vinyl ether resin, polyamide resin, polycarbonate resin, polysulfone resin, polyester resin, Examples include polyvinyl acetal resins, polyvinylidene chloride resins, polyurethane resins, and the like.

When the molecular chain is an ethylene/vinyl acetate copolymer resin, (meth)acrylic resin, or the like, the reactive group may be a methoxycarbonyl group or the like contained in the molecular chain. In this case, the nonpolar polymer in the present embodiment refers to the molecular structure of the portion containing a methoxycarbonyl group or the like (in this case, the molecular chain is a structure in which the molecular chain itself contains a reactive group In this case, if the molecular chain portion excluding the reactive group is non-polar, it is considered to be a non-polar polymer). Alternatively, another reactive group (a reactive group different from the methoxycarbonyl group) may be separately introduced into the ethylene/vinyl acetate copolymer resin, (meth)acrylic resin, or the like by graft polymerization or the like.

As the nonpolar polymer, at least one polymer selected from the group consisting of polypropylene, ethylene-vinyl acetate copolymer resin, and acrylic resin from the viewpoint of availability, low specific gravity, versatility, and/or processability. A non-polar polymer is preferred. Among these, polypropylene is more preferred. These olefinic resins may contain other copolymerizable units. Moreover, these olefinic resins can be used singly or in combination of two or more.

(High molecular)
Examples of the polymer comprising the above molecular chain and reactive group include various polymers in which the above molecular chain and the above reactive group are combined. Examples thereof include polypropylene, ethylene/vinyl acetate copolymer resin, and acrylic resin having at least one reactive group among the above reactive groups. As the polymer, a polymer in which a reactive group is bonded to a molecular chain like a pendant group is more preferable, and for example, a graft copolymer is preferable. Among the above polymers, maleic anhydride-modified polypropylene (MAPP), which has a maleic anhydride group as a reactive group and a polypropylene molecular chain, is used from the viewpoint of activating the movement of the reactive group with respect to the molecular chain. Most preferably used.

(molecular weight)
The weight-average molecular weight of the polymer containing a reactive group and a nonpolar polymer is preferably 5,000 or more, more preferably 10,000 or more, still more preferably 15,000 or more, and 200,000 or less. is preferred, 150,000 or less is more preferred, and 100,000 or less is even more preferred. When the weight-average molecular weight is less than 5,000, the mechanical properties of the cellulose composite tend to deteriorate, and when it exceeds 200,000, the reactive groups are insufficient, making it difficult to produce a cellulose composite exhibiting desired physical properties. tends to be difficult. The weight average molecular weight can be calculated using high temperature gel permeation chromatography (high temperature GPC) and converted to polystyrene, and then converted to polypropylene using the Q factor.

(graft rate)
For example, when maleic anhydride is grafted onto polypropylene to obtain MAPP, polymer radicals are generated on the polypropylene chain in the grafting reaction, and maleic anhydride is grafted onto these polymer radicals. On the other hand, a molecular scission reaction of polypropylene chains occurs as a competing reaction of the graft reaction. Since the molecular scission reaction is superior to the graft reaction, the graft ratio and the molecular weight are in a trade-off relationship, such that the molecular weight of MAPP obtained decreases as the graft ratio increases.

When the graft ratio is low (that is, when the graft copolymer has a high molecular weight and the MA concentration is low), emulsification of the polymer is difficult, and when the graft ratio is high, the molecular weight of the graft copolymer increases. extremely low. In addition, when the molecular weight of the graft copolymer is low, the graft copolymer trapped in the cellulose composite is also low molecular weight, so the properties of the cellulose composite itself (for example, strength, etc.) may decrease.

Therefore, when the polymer is a graft copolymer (for example, MAPP), the graft ratio is preferably 0.2% or more, more preferably 1.0%, from the viewpoint of facilitating the formation of an emulsion of the polymer. The above is more preferable. In addition, the graft ratio is preferably 4.0% or less, more preferably 3.0% or less, from the viewpoint of suppressing deterioration in the properties of the cellulose composite/resin composition due to a decrease in the molecular weight of the polymer.

(melting point)
The melting point of the above polymer depends on the melting point of the non-polar polymer used for the molecular chain. For example, when a polypropylene-based polymer is used for the molecular chain, the melting point of the polymer is about 80° C. or higher and 175° C. or lower.

[Captured macromolecules]
The macromolecules trapped in the cellulose composite are the same as the macromolecules described above. However, the non-polar polymer bound to the hydroxyl group of cellulose through the reactive group, that is, the polymer having the non-polar polymer with this reactive group, and the captured polymer are the same. is a polymer of

In the present embodiment, when the cellulose composite is subjected to Soxhlet extraction, the extracted insoluble component (extracted insoluble component) contains the cellulose composite, and the extracted soluble component (extractable soluble component) contains the polymer. If so, the macromolecules are said to be "entrapped" in the cellulose composite. For example, the cellulose composite is Soxhlet-extracted to separate the extractable insoluble components from the extractable soluble components. Next, FT-IR measurement, ¹ H-NMR measurement and/or ¹³ C-NMR measurement are performed for each of the extracted insoluble component and the extracted soluble component. As a result, a peak derived from the skeleton, bond, and/or group contained in the cellulose composite was observed in the extractable insoluble component, and the skeleton, bond, and/or group contained in the polymer was observed in the extractable soluble component. If a derived peak is observed, it can be assumed that the macromolecules are trapped in the cellulose composite.

Here, a composite formed by binding MAPP to CNF is taken as an example of a cellulose composite. CNF itself is insoluble in xylene, while MAPP itself is soluble. In this case, if xylene is used as an organic solvent for the Soxhlet extraction, an extraction-insoluble component and an extraction-soluble component are obtained. Then, when the amount (wt%) of the extracted insoluble component is greater than the amount (wt%) of CNF used for the synthesis of the cellulose composite, and the presence of an ester bond is confirmed by NMR measurement , indicating that MAPP was bound to CNF via an ester bond.

In this case, a peak based on the polypropylene (PP) skeleton was observed by ¹³ C-NMR measurement of the extractable soluble component, and a peak based on the MA skeleton was observed by ^FT -IR measurement and ¹ H-NMR measurement. A peak based on the cellulose skeleton was observed by H-NMR measurement, and a carbonyl peak based on the MA skeleton was observed by FT-IR measurement of the extracted insoluble component and ¹³ C-NMR measurement, and cellulose skeleton was observed by ¹³ C-NMR measurement. is observed, it can be assumed that the macromolecules are trapped in the cellulose composite.

<Cellulose composite/resin composition>
A cellulose composite/resin composition according to the present embodiment is a composition obtained by dispersing a cellulose composite in a predetermined non-polar resin. Since the cellulose composite is a state in which a nonpolar polymer is bound to cellulose, it can be substantially uniformly dispersed in a nonpolar resin. Also, when there is a polymer trapped in the cellulose composite, the cellulose composite can be more easily dispersed in the non-polar resin.

[resin]
Various resins can be used as the resin in the cellulose composite/resin composition. For example, resins include thermoplastic resins, thermosetting resins, and/or photocurable resins. A nonpolar or hydrophobic resin is preferably used as the resin in the cellulose composite/resin composition.

Examples of thermoplastic resins include styrene resins, acrylic resins, aromatic polycarbonate resins, aliphatic polycarbonate resins, aromatic polyester resins, aliphatic polyester resins, olefin resins (e.g., aliphatic polyolefin resins, cyclic olefin-based resins), polyamide-based resins, polyphenylene ether-based resins, thermoplastic polyimide-based resins, polyacetal-based resins, polysulfone-based resins, and amorphous fluorine-based resins.

Examples of thermosetting resins include epoxy resins, acrylic resins, oxetane resins, phenol resins, urea resins, polyimide resins, melamine resins, unsaturated polyester resins, silicon resins, polyurethane resins, allyl ester resins, and diallyl phthalate resins. be done.

Examples of photocurable resins include epoxy resins, acrylic resins, and oxetane resins.

As the resin, it is preferable to use a thermoplastic resin such as an olefin resin (polypropylene, etc.) from the viewpoint that it can be applied to various industries and is relatively easy to mold.

<Details of cellulose-containing resin composition>
A cellulose-containing resin composition is a composition containing a crystalline resin and the cellulose composite according to the present embodiment.

(Crystalline resin)
An olefin-based resin can be used as the crystalline resin. Olefin resins include polypropylene, polyethylene, polymethylpentene, ethylene/vinyl acetate copolymer resin, vinyl chloride resin, styrene resin, (meth)acrylic resin, vinyl ether resin, polyamide resin, polycarbonate resin, polysulfone resin, Examples include polyester resins, polyvinyl acetal resins, polyvinylidene chloride resins, polyurethane resins, and the like. Here, the crystalline resin may be used alone or in combination of two or more of these resins. In the present embodiment, it is preferable to use polypropylene as the crystalline resin from the viewpoints of good resin properties, availability, and the like. The crystalline resin means a resin having a melting peak when measured according to ISO 3146 (method for measuring plastic transition temperature, JIS K7121).

(Cellulose content)
The concentration of cellulose (cellulose, CNF, and/or MFC) in the cellulose-containing resin composition is within a range where aggregation of cellulose can be suppressed in the cellulose-containing resin composition and a network structure of cellulose is formed. preferably adjusted. Further, the cellulose concentration achieves a predetermined laminate height when, for example, a 3D printer filament formed using a cellulose-containing resin composition is used in a material extrusion deposition type (FDM method) 3D printer. It is also preferable that the concentration be adjusted to a possible value. For example, the concentration of cellulose in the cellulose-containing resin composition must exceed 0 wt%, preferably 3 wt% or less, more preferably 2.6 wt% or less, and even more preferably 1.5 wt% or less.

<Other additives>
The cellulose composite, the cellulose composite/resin composition, and/or the cellulose-containing resin composition according to the present embodiment, the physical properties of the cellulose composite, the cellulose composite/resin composition, and/or the cellulose-containing resin composition, etc. Extenders, plasticizers, moisture absorbers, physical property modifiers, reinforcing agents, coloring agents, flame retardants, antioxidants, anti-aging agents, conductive agents, antistatic agents, UV absorbers , UV dispersants, solvents, fragrances, deodorants, pigments, dyes, fillers, diluents, talc, and other additives may be added.

<Application: Products>
The cellulose-containing resin composition according to this embodiment can be used for various purposes. Specifically, it can be used for various products such as automobile parts, home appliances, housing/building materials, and packaging materials. Further, since the cellulose-containing resin composition according to the present embodiment does not easily shrink in volume even if it is cooled after being melted by heat, filaments for 3D printers, especially filaments for 3D printers of material extrusion deposition type (FDM method) 3D printers is useful as

<Method for producing cellulose composite>
The method for producing a cellulose composite according to this embodiment generally includes the following steps. That is, the method for producing a cellulose composite comprises a mixing step of mixing cellulose having a hydroxyl group and a polymer having a reactive group to prepare a mixture, and a heating step of heating the mixture. Moreover, the method for producing a cellulose composite can further include a drying step of drying the cellulose composite obtained after the heating step. The heating step can be performed after the mixing step, or the mixing step and the heating step can be performed at the same time (the mixing step can be performed while heating).

[Mixing process]
First, cellulose having hydroxyl groups, that is, a predetermined amount of cellulose fibers, cellulose nanofibers (CNF), and/or microfibrillated cellulose (MFC), and a predetermined amount of polymers (that is, reactive groups capable of reacting with hydroxyl groups) and the molecular chain is a non-polar polymer) are mixed to prepare a mixture. The mixing method is not particularly limited, and manual mixing, mixing using a stirrer or mixer, or the like can be appropriately selected.

(Cellulose used for mixing)
Here, when cellulose fibers are used as cellulose, the cellulose fibers are used in a state in which they contain moisture. When CNF is used as cellulose, it is preferable to use an aqueous dispersion of cellulose, that is, an aqueous dispersion of CNF (hereinafter referred to as "CNF aqueous dispersion"). As the CNF of the CNF aqueous dispersion, the various CNFs described above can be used. It is also possible to use cellulose fibers previously hydrophobized by chemical treatment. However, when the cellulose fibers are hydrophobized in advance by chemical treatment, the number of steps such as refining accompanying the chemical treatment is increased, resulting in an increase in cost and labor. On the other hand, in the present embodiment, chemically untreated cellulose fibers and/or an aqueous dispersion of cellulose can be used, which eliminates the need for the above steps and is very advantageous in terms of cost and the like. When using microfibrillated cellulose (MFC) as cellulose, it is preferable to use MFC obtained by defibrating (beating) cellulose in water. Since MFC has a lower fibrillation degree than CNF, it drains well and is less likely to aggregate strongly.

The amount of water contained in cellulose fibers varies depending on the manufacturing method of cellulose fibers. For example, methods for producing cellulose fibers include mechanical fibrillation in which cellulose is fibrillated to a fiber width of several tens to 200 nm using a grinder or ultrahigh-pressure water, TEMPO oxidation, phosphoric acid esterification, etc., to achieve a fiber width of 10 nm. There is a chemical processing defibration that defibrates to a fiber width of about level. Both are aqueous dispersions because mechanical fibrillation generates heat and chemical fibrillation requires chemical treatment in an aqueous solution. In the case of mechanical defibration, although it varies depending on the degree of defibration, the solid content concentration of cellulose fibers is usually about 2 wt% or more and 10 wt% or less (note that at about 10 wt%, the shape of cellulose fibers is becomes sherbet-like). On the other hand, in the case of chemical defibration, the solid content concentration of the cellulose fibers is about 0.5 wt% or more and 2 wt% or less (2 wt% is the upper limit of the solid content concentration that maintains the gel state). This embodiment is advantageous in that it can be applied not only to water dispersion CNF but also to fibers such as pulp.

The solid content concentration of the CNF water dispersion is preferably a concentration at which the viscosity becomes a level that allows stirring without temperature unevenness when mixed with a polymer emulsion. For example, the solid content concentration of the CNF aqueous dispersion is 0.5 wt% or more, preferably 2 wt% or more, may be 5 wt% or more, and 15 wt% or less, from the viewpoint of facilitating mixing with the polymer. and preferably 10 wt % or less. In addition, the viscosity of the CNF aqueous dispersion (for example, using a Brookfield viscometer, a representative value of the viscosity when measured at 25 ° C. and 60 rpm) is 700 mPa s or more, and 3,000 mPa s or more. may be 6,000 mPa·s or more, may be 40,000 mPa·s or more, and is 130,000 mPa·s or less, preferably 110,000 mPa·s or less.

(Polymer used for mixing)
As the polymer used in the mixing step, it is preferable to use a polymer aqueous emulsion in which polymer fine particles are dispersed in water. As the polymer constituting the polymer aqueous emulsion, the various polymers described above can be used. A system (emulsion) in which polymer microparticles (dispersoids) are stably dispersed in water (dispersion medium) is called "latex." However, in this embodiment, such a system shall be referred to as an "emulsion" in accordance with common practice.

From the viewpoint of reactivity with cellulose, the proportion of solids in the polymer aqueous emulsion is 5 wt% or more, preferably 10 wt% or more, more preferably 15 wt% or more, still more preferably 20 wt% or more, and 25 wt% or more. There may be. In addition, the proportion of solids in the aqueous polymer emulsion is 45 wt % or less, preferably 30 wt % or less, from the viewpoint of facilitating preparation of the emulsion.

Various emulsions can be used as the polymer water-based emulsion. Among various emulsions, it is preferable to use a maleic anhydride-modified polypropylene (MAPP) emulsion, an ethylene-vinyl acetate copolymer (EVA) emulsion, and an acrylic emulsion of an acrylic resin. Among them, the MAPP emulsion is most preferable because the reactive groups are suspended from the molecular chain, so that the reactive groups can easily approach the hydroxyl groups of the cellulose, and the collision frequency of the reactive groups with the hydroxyl groups can be improved. By mixing the aqueous dispersion of cellulose and the aqueous polymer emulsion, mixing at the molecular level can be facilitated at a low temperature or in a state in which thermal deterioration is less than in the case of mixing solids.

(Mixed amount of cellulose and polymer)
The mixing ratio of cellulose and polymer can be defined by the solid content ratio of cellulose and polymer. That is, the solid content ratio of cellulose (cellulose fiber, CNF, or MFC) in the mixture is 3 wt% or more, may be 5 wt% or more, preferably 10 wt% or more, and may be 20 wt% or more, From the viewpoint of suppressing aggregation of cellulose (typically CNF) and appropriately forming a complex with a polymer, the content is 50 wt% or less, preferably 40 wt% or less.

On the other hand, the solid content ratio of the polymer in the mixture may be a ratio equal to or higher than the solid content ratio of cellulose, preferably a higher ratio, for example, 10 wt% or more, may be 15 wt% or more, or 25 wt%. or more, or 45 wt % or more.

Therefore, when mixing cellulose fibers, CNF, and/or MFC with a polymer, the ratio of the solid content ratio of cellulose to the solid content ratio of the polymer in the mixture, that is, the solid content ratio of cellulose: the solid content of the polymer The cellulose (moisture-containing cellulose Fiber, CNF aqueous dispersion, or MFC) and polymer (water-based emulsion of polymer) are weighed and mixed.

[Heating process]
In the heating step, the mixture obtained in the mixing step is controlled to a predetermined temperature or less and heated for a predetermined time. This heating step causes the hydroxyl groups of the cellulose to react with the reactive groups of the polymer to form predetermined bonds, through which the polymer is bound to the cellulose. Here, when the reactive group is at least one reactive group selected from the group consisting of a succinic anhydride group, a carbonyl group, and a carboxyl group, the bond formed by the hydroxyl group of cellulose and the reactive group is an ester It is a bond. That is, in this case, the esterification reaction proceeds in the heating step.

The reaction temperature in the heating step is 50°C or higher, preferably 70°C or higher, and may be 80°C or higher, from the viewpoint of enabling formation of a predetermined bond (eg, an ester bond). In addition, the reaction temperature is 200° C. or lower, preferably 160° C. or lower, and may be 145° C. or lower in order to suppress thermal deterioration of cellulose.

In addition, the heating step preferably heats the mixture under reduced pressure. The pressure during heating may be less than normal pressure. For example, the pressure in the heating step may be approximately 0.09 MPa or less. Heating under reduced pressure helps remove water from the system. After the heating step, a cellulose composite powder is obtained. Moreover, the reaction product obtained after the heating step may be filtered under reduced pressure (reduced pressure filtration step). That is, the reaction product according to this embodiment can be subjected to dehydration treatment. By going through the vacuum filtration step, it is possible to apply a more powerful dehydration treatment to the reaction product. For the heating step, for example, a device such as a planetary stirring type heating and reduced pressure drying device can be used. In addition, the heating process is a process of heating and reacting the mixture in a pot of a normal pressure open system, followed by a process of primary dehydration treatment with a centrifuge, a filter press, etc. It may include a step of drying under reduced pressure using (secondary dehydration treatment step). From the viewpoint of the amount of cellulose composite powder to be obtained and/or production costs, the heating step is preferably a step in which the primary dehydration treatment step and the secondary dehydration treatment step are combined.

Here, this cellulose composite contains macromolecules trapped in the cellulose composite. By using cellulose (water-containing cellulose fiber, CNF aqueous dispersion, or MFC) and an aqueous emulsion of a polymer, not only a cellulose composite is formed, but also a non-polar polymer bound to the cellulose is highly It is presumed that the molecules are easily entangled and the macromolecules are easily trapped in the cellulose composite.

[Drying process]
A drying process dries the water|moisture content which remains in the cellulose composite obtained after a heating process. For example, the drying step is a step of drying the cellulose composite with warm air. The temperature of the warm air is, for example, about 80° C., and the drying time is about 8 hours. However, the temperature and the drying time are not limited to these, as long as the thermal deterioration of the cellulose contained in the cellulose composite can be suppressed. In the drying step, it is preferable to continue drying until, for example, the water content in the cellulose composite becomes approximately 5 wt % or less.

<Method for producing cellulose composite/resin composition>
The cellulose composite/resin composition can be prepared through a kneading step of kneading the cellulose composite obtained above with a predetermined nonpolar resin at a predetermined temperature for a predetermined time. After the kneading step, a curing step for curing the obtained cellulose composite/resin composition may be further carried out.

[Kneading process]
The kneading step is a step of kneading the cellulose composite and a predetermined nonpolar resin under a predetermined temperature environment, and the kneading method is not particularly limited, and the kneading may be performed in one step or in a plurality of times. It can also be divided into steps. The kneading step can be carried out using, for example, a kneader, a twin-screw kneader, and/or an injection molding machine, which is a device for kneading the charged materials by rotating blades in a container. The cellulose composite used in the kneading step may be in the form of powder, or may be in the form of pellets from the viewpoint of ease of handling during compounding. On the other hand, the shape of the non-polar resin is not particularly limited, and may be in the form of pellets or powder.

(Quantity of cellulose composite and resin)
There is no particular limit to the amount of cellulose composite added to the resin. For example, when the solid content ratio of the cellulose composite in the cellulose composite/resin composition is a (wt%) and the solid content ratio of the resin is b (wt%), a:b is 1:1 to 1 :9, preferably about 1:2 to 1:5. The cellulose (CNF) content of the cellulose composite is preferably 5 wt% or more, more preferably 10 wt% or more, still more preferably 15 wt% or more, still more preferably 20 wt% or more, preferably 40 wt% or less, and 35 wt%. The following are more preferable, and 30 wt% or less is even more preferable. The cellulose (CNF) content in the cellulose composite/resin composition is preferably 2 wt% or more, more preferably 3 wt% or more, and preferably 15 wt% or less, from the viewpoint of ensuring mechanical properties and raw material costs. 10 wt% or less is more preferable, and 5 wt% or less is considered to be even more preferable.

(Temperature during kneading)
Further, in the kneading step, it is preferable to carry out kneading while heating. The heating temperature during kneading is a temperature higher than or equal to the temperature at which the resin melts, from the viewpoint of melting the resin and dispersing the cellulose composite in the melted resin (that is, adding the cellulose composite to the resin melt). It is preferable to control the temperature below the temperature at which the cellulose contained in the cellulose composite is less likely to be thermally degraded. Specifically, in the kneading step, when a non-polar resin used for kneading, for example, a polypropylene resin is used as the non-polar resin, from the viewpoint of not applying excessive heat to the cellulose composite while the resin is in a molten state, the temperature is 175 ° C. or higher. It is preferable to control the heating temperature, and it is preferable to control the heating temperature to 190° C. or 220° C. or less.

In the kneading step, for example, it is preferable to first melt the resin using a twin-screw extruder or the like, add the cellulose composite to the melted resin, and knead. By adopting such an order, heat (amount of heat) applied to the cellulose composite can be reduced, and thermal deterioration of the cellulose contained in the cellulose composite can be suppressed.

In the cellulose composite/resin composition obtained through the kneading process, the cellulose composite is substantially uniformly dispersed in the resin. This dispersed state can be confirmed by, for example, an infrared imaging method, a three-dimensional TEM, or the like.

<Method for producing cellulose-containing resin composition>
The cellulose-containing resin composition according to this embodiment can be produced through a step of kneading the cellulose composite and the crystalline resin obtained above. This kneading step may be the same as the kneading step described above. For example, a mixture obtained by mixing a crystalline resin, a cellulose composite, and/or other additives (such as talc) at a predetermined mixing ratio (for example, various shapes such as powder, paste, and pellets can be used). can be kneaded in a kneading device to produce a cellulose-containing resin composition. Further, after kneading, the cellulose-containing resin composition is extruded from a predetermined die in the form of filaments to produce filaments for 3D printers having a predetermined diameter.

<Effect of Embodiment>
In the cellulose-containing resin composition according to this embodiment, the crystalline resin contains the cellulose composite according to this embodiment. In the cellulose composite, a non-polar polymer is bonded to the hydroxyl group of cellulose through a reactive group. The cellulose composite can be substantially uniformly dispersed in the resin without the presence of the cellulose. Therefore, in the cellulose-containing resin composition according to the present embodiment, for example, since cellulose fibers, CNF, and / or MFC are uniformly dispersed in olefin resins such as polyethylene and polypropylene, raw material costs and manufacturing facility costs can be reduced and a high-performance structural material can be manufactured.

In addition, since the cellulose composite uses a cellulose aqueous dispersion and a polymer aqueous emulsion, the cellulose composite can be prepared while suppressing thermal deterioration of cellulose. As a result, the cellulose-containing resin composition can exhibit properties that incorporate the inherent properties of cellulose.

Furthermore, the cellulose composite can be prepared in a state in which the polymer used for preparing the cellulose composite is captured. As a result, when the cellulose-containing resin composition produced using the cellulose composite according to the present embodiment is added to the resin, the cellulose is more easily dispersed in the resin.

In addition, the cellulose-containing resin composition according to the present embodiment contains a predetermined amount of cellulose in the crystalline resin, and the cellulose is substantially uniformly dispersed in the crystalline resin to form a network without aggregation. Therefore, volumetric shrinkage can be greatly reduced even when the material is cooled after thermal melting. Thereby, the cellulose-containing resin composition according to the present embodiment can be utilized as a high-performance 3D printer filament.

Furthermore, the 3D printer filament comprising the cellulose-containing resin composition according to the present embodiment contains a predetermined amount of cellulose in the crystalline resin (eg, polypropylene), and is , good formability (that is, properties that can suppress the occurrence of cracks and cracks in the model because shrinkage after cooling after hot melting can be suppressed, and properties that have good workability after cooling after hot melting, etc.) and dimensional stability.

A more specific description will be given below with examples. In addition, it cannot be overemphasized that these examples are illustrations and should not be interpreted restrictively.

[Synthesis Examples 1 and 2: Cellulose composite]
First, each compounded substance was mixed at the compounding ratio shown in Table 1 to obtain a mixture. Subsequently, the resulting mixture was heated under reduced pressure using a vertical kneader/agitator (Trimix TX-50, manufactured by Inoue Seisakusho). The reduced-pressure heating conditions were a set temperature of 145° C., a heating time of 30 minutes, and an internal pressure of 0.09 MPa. As a result, the cellulose composite having a CNF content of 25 wt% according to Synthesis Example 1 (hereinafter referred to as "Cellmapp", and "X" in "CellmappX" indicates the CNF content. For example, Cellmapp25 has a CNF content of 25 wt%) powder was prepared. Subsequently, the obtained powder of Cellmapp 25 according to Synthesis Example 1 was dried using a warm air dryer. Drying conditions were set at 80° C. for 8 hours. Cellmapp50 according to Synthesis Example 2 was also prepared in the same manner.

In Table 1, the unit of the compounding amount of each compounding substance is "wt%". Further, the details of the compounded substances are as follows.
・ Cellulose nanofiber (CNF) slurry (BiNFi-s WFo-10010: solid content 10 wt%, manufactured by Sugino Machine Co., Ltd.)
・MAPP emulsion (aqueous emulsion of maleic anhydride-modified polypropylene (MAPP): prepared with water to a solid content of 25 wt%.)

In Table 1, the blending amount of CNF slurry is represented by the amount of CNF contained in the CNF slurry, and the blending amount of MAPP emulsion is represented by the amount of MAPP contained in the MAPP emulsion.

[Synthesis Examples 3-4]
Subsequently, the mixture obtained by mixing each compounding substance in the compounding ratio shown in Table 2 was kneaded. The mixture obtained after kneading was pulled out as a strand, cooled in a water bath, and pelletized. As a result, cellulose composites according to Synthesis Example 3 and Synthesis Example 4 were obtained (hereinafter, the cellulose composite according to Synthesis Example 3 is referred to as "CNF-15MB", and the cellulose composite according to Synthesis Example 4 is referred to as "CNF-25MB". called.). Table 3 shows the compositions of the constituent components of the cellulose composites according to Synthesis Examples 3 and 4. For kneading, a twin-screw extruder (KZW20TW, manufactured by Technobell Co., Ltd.) was used. Further, the kneading conditions are as follows.
・Screw rotation speed: 200 rpm
- Kneading temperature: Set the temperature of zone 1 to 130°C, the temperature of zone 2 to 160°C, and the temperature of the head to 180°C.

In Table 2, the unit of the compounding amount of each compounding substance is "wt%". Further, the details of the compounded substances are as follows.
・ PP powder (PP powder for dilution (PP powder obtained by freeze-pulverizing homotype Prime Polypro J107G (MFR: 30, manufactured by Prime Polymer Co., Ltd.))

(Confirmation of distributed state)
The dispersion state of CNF in the cellulose composites according to Synthesis Example 3 and Synthesis Example 4 was evaluated using the coefficient of variation CV calculated using infrared spectroscopic imaging. Frontier-Spotlight 400 (PerkinElmer) was used as an infrared spectrometer, and the measurement conditions were set to resolution: 8 cm ⁻¹ , number of integrations: 4, pixel size: 1.56 μm×1.56 μm, measurement area: 200 μm×200 μm. In addition, the analysis of the imaging results was performed by dividing the peak area at 1050 cm ⁻¹ derived from cellulose by the peak area at 1380 cm ⁻¹ derived from polypropylene (PP) for each pixel size of 16,384 points. It was analyzed by expressing it with a gradation. Here, the coefficient of variation CV is obtained by taking 16,384 pixels as a plurality of clusters (window size), obtaining the standard deviation (SD) and the average value (Avg.) in the cluster, and averaging the standard deviations Calculated by dividing by the value. Therefore, the smaller the standard deviation, the smaller the CV value. That is, when the window size is small, the small CV value indicates that the presence of cellulose is uniform.

Specifically, Synthesis Example 3 (cellulose composite containing Cellmapp25) and Synthesis Example 4 (cellulose composite containing Cellmapp50) both have CV values as low as 0.0 to less than 0.4, and CNF is good. shown to be dispersed. In addition, the CV value of Synthesis Example 3 was lower than that of Synthesis Example 4, indicating that the dispersibility was more excellent.

[Example]
Each compounded substance was kneaded at the compounding ratio shown in Table 4 to prepare a resin for filaments for 3D printers, and then the resin was formed into filaments. Here, filaments for 3D printers were produced as follows. First, Laboplastomill μ (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used as a kneading device. Mixed pellets of the compounded substances dry-blended at the compounding ratio shown in Table 4 were put into a kneading device. The kneading temperature was set to 173° C. for barrel 1, 175° C. for barrel 2, and 178° C. for the die. to prepare filaments for 3D printers (diameter: 1.75 mm±0.1 mm) according to Comparative Example 1 and Examples 1 to 6.

In Table 4, the unit of the compounding amount of each compounding substance is "g". Further, the details of the compounded substances are as follows.
・Polypropylene (PP): PM731M (random PP, manufactured by SunAllomer Co., Ltd.)
・Talc-70MB: Talc 70wt% Masterbatch (Talc-70MB): PEX1470 (Talc: LDPE = 70:30), Tokyo Ink Co., Ltd.)
· CNF-15MB: cellulose composite according to Synthesis Example 3 · CNF-25MB: cellulose composite according to Synthesis Example 4

(Molding test)
Using the 3D printer filaments according to Comparative Example 1 and Examples 1 to 6, a box-shaped structure (size: length 39 mm x width 33 mm x height 18 mm) was prototyped. A 3D printer (MF-2500EP, manufactured by MUTOH INDUSTRIES CO., LTD.) was used for modeling the structure, and the temperature during modeling was set to 200° C. for the nozzle and 100° C. or 110° C. for the heater bed. The nozzle operation was set at a packing density of 40% and a speed of 20 to 25 mm/s. That is, the box shape was formed by forming a flat bottom portion as the first layer and forming wall portions one by one around the bottom portion in the direction perpendicular to the bottom surface. It should be noted that the box-shaped model to be modeled is completed by stacking 59 layers.

(Evaluation method)
Since the box-shaped structure by the above 3D printer is completed by laminating 59 layers, the ease of modeling is determined by the height of the wall that can be modeled (that is, the first layer to the x layer and x is the number of layers that can be formed.). Specifically, the layer thickness of the first layer was set to 0.4 mm, and the layer thickness of each layer after the second layer was set to 0.3 mm in the setting at the time of modeling of the 3D printer. . Then, evaluation was performed by calculating the height of the wall from the number of layers that could be laminated by the 3D printer and the set layer thickness. It can be determined that the higher the height of the wall, the easier it is to form. In addition, one of the important evaluation indices for ease of modeling is the stable formation of the first layer. If the first layer is warped or the like, the contact area with the heater bed becomes smaller, and the resistance of the resin against the heater bed becomes smaller. This is because it becomes impossible to form a model up to

Table 5 shows the molding results when the heater bed temperature is 110°C, and Table 6 shows the molding results when the heater bed temperature is 100°C.

As shown in Table 5, when the temperature of the heater bed was 110° C., only 25 layers (the wall height was 7.6 mm) could be formed when using the 3D printer filament according to Comparative Example 1. On the other hand, when using the 3D printer filaments according to Examples 1 to 4, it was shown that up to 59 layers (the height of the wall portion is 17.8 mm) can be modeled.

Further, as shown in Table 6, when the temperature of the heater bed is 100° C., only up to 4 layers (the wall height is 1.3 mm) can be formed when the 3D printer filament according to Comparative Example 1 is used. I didn't. On the other hand, when using the 3D printer filament according to Example 1, it is possible to model up to 59 layers (wall height is 17.8 mm), and when using the 3D printer filament according to Examples 2 to 6, at least It was shown that 5 or more layers (with a wall height of 1.6 mm) can be formed. That is, as shown in FIG. 1, at least in Examples 1 to 6, it was shown that lamination of more than twice the number of layers as compared to Comparative Example 1 was possible. In addition, in Examples 1 to 6, it was also shown that the first layer can be shaped without warping if the height is equal to or less than the height of each wall. In other words, even when the temperature of the heater bed of the 3D printer is lower than 110° C., it was shown that warping of the first layer can be suppressed in Examples 1 to 6. In particular, in Example 1, it was shown that the inhibitory effect was remarkable.

In addition, when comparing Comparative Example 1 and Example 1, as shown in Table 4, by setting the CNF concentration in the resin to about 1.3%, it was found that there was a significant improvement in the ease of modeling. shown.

Furthermore, in the 3D printer filaments according to Example 1, and Examples 4, 5, and 6, the amount of CNF-15MB added was varied. That is, the CNF concentrations in the resins for filaments for 3D printers according to Example 1, and Examples 4, 5, and 6 were 1.3 wt%, 0.7 wt%, and 1.9 wt% in this order. , 2.5 wt %. Then, as shown in Table 6, when the 3D printer filament according to Example 4 was used, up to 39 layers could be modeled, and when the 3D printer filament according to Example 5 was used, up to 8 layers could be modeled. Further, when the 3D printer filament according to Example 6 was used, up to nine layers could be modeled. Therefore, it was shown that the number of layers that can be laminated can be controlled by adjusting the CNF concentration in the resin.

Also, in Comparative Example 1, talc is contained in the resin. Talc is added for the purpose of suppressing heat shrinkage when the filament melts and solidifies during modeling with a 3D printer. As shown in Table 6, when the temperature of the heater bed was 100 ° C., the number of layers was up to 4 when the 3D printer filament according to Comparative Example 1 was used, while Example 3 containing no talc When such a filament for a 3D printer was used, the number of layers was 16 layers. From this result, it was shown that CNF suppresses thermal shrinkage during modeling.

From the above, it was shown that the cellulose-containing resin composition (PP-based 3D filament composition) according to the example greatly improved the moldability of a modeled object by a 3D printer by blending CNF. In addition, it was shown that this improvement effect can be realized only by blending about 1 wt% of CNF with respect to the resin, so that a significant reduction in raw material costs can be realized.

[Example using microfibrillated cellulose]
A composite of MFC and PP was prepared using microfibrillated cellulose (MFC).

(Microfibrillated cellulose (MFC))
A cotton linter was used as a raw material for MFC. This was beaten by a refiner to prepare an average fiber diameter of 24 μm (distribution: 8 μm to 50 μm) and an average fiber length of 810 μm (distribution: ~3 mm) to obtain MFC according to this example.

(Preparation of Microfibrillated Cellulose (MFC)/PP Composite)
A mixture obtained by mixing each compounding substance at the compounding ratio shown in Table 7 was kneaded. The mixture obtained after kneading was pulled out as a strand, cooled in a water bath, and pelletized. For kneading, a twin-screw extruder (KZW20TW, manufactured by Technobell Co., Ltd.) was used. Further, the kneading conditions are as follows. As a result, two types of MFC/PP composites (MFC-30MB(h) and MFC-30MB(b)) were obtained.
・Screw rotation speed: 200 rpm
- Kneading temperature: Set the temperature of zone 1 to 130°C, the temperature of zone 2 to 160°C, and the temperature of the head to 180°C.

In Table 7, the unit of the compounding amount of each compounding substance is "wt%". Further, the details of the compounded substances are as follows.
・PP is a homo type (PP (homo)) prime polypro J107G (MFR: 30, manufactured by Prime Polymer Co., Ltd.) and a block type (PP (block)) prime polypro J707G (MFR: 30, manufactured by Prime Polymer Co., Ltd.). Two types were used.
・ MAPP: Kayabrid 002PP (graft rate: 2%, manufactured by Kayaku Noorion Co., Ltd.)

After kneading each compounded substance at the compounding ratio shown in Table 8 to produce a resin for filaments for 3D printers, the resin was made into filaments. Here, filaments for 3D printers were produced as follows. First, Laboplastomill μ (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used as a kneading device. Mixed pellets of compounded substances dry-blended at the compounding ratio shown in Table 8 were put into a kneading device. The kneading temperature was set to 173° C. for barrel 1, 175° C. for barrel 2, and 178° C. for the die. 3D printer filaments (diameter: 1.75 mm±0.1 mm) according to Examples 7 to 12 and Comparative Example 2 were produced.

In Table 8, the unit of the compounding amount of each compounding substance is "g". Further, the details of the compounded substances are as follows. In Comparative Example 2, the strand could not be drawn because the filament broke.
・Polypropylene (PP): PM731M (random PP, manufactured by SunAllomer Co., Ltd.)
・Talc-70MB: Talc 70wt% Masterbatch (Talc-70MB): PEX1470 (Talc: LDPE = 70:30), Tokyo Ink Co., Ltd.)
- MFC-30MB (h) and (b): MFC/PP composites shown in Table 7 above

(Molding test)
Using the 3D printer filaments according to Examples 7 to 12, a box-shaped structure (size: length 39 mm x width 33 mm x height 18 mm) was prototyped. A 3D printer (MF-2500EP, manufactured by MUTOH INDUSTRIES CO., LTD.) was used for modeling the structure, and the nozzle temperature was 200° C. and the heater bed was 110° C. during modeling. The nozzle operation was set at a packing density of 40% and a speed of 20 to 25 mm/s. That is, the box shape was formed by forming a flat bottom portion as the first layer and forming wall portions one by one around the bottom portion in the direction perpendicular to the bottom surface. It should be noted that the box-shaped model to be modeled is completed by stacking 59 layers.

(Evaluation method)
Since the box-shaped structure by the above 3D printer is completed by laminating 59 layers, the ease of modeling is determined by the height of the wall that can be modeled (that is, the first layer to the x layer and x is the number of layers that can be formed.). Specifically, the layer thickness of the first layer was set to 0.4 mm, and the layer thickness of each layer after the second layer was set to 0.3 mm in the setting at the time of modeling of the 3D printer. . Then, evaluation was performed by calculating the height of the wall from the number of layers that could be laminated by the 3D printer and the set layer thickness. It can be determined that the higher the height of the wall, the easier it is to form. In addition, one of the important evaluation indices for ease of modeling is the stable formation of the first layer. If the first layer is warped or the like, the contact area with the heater bed becomes smaller, and the resistance of the resin against the heater bed becomes smaller. This is because it becomes impossible to form a model up to Table 9 shows the molding results when the heater bed temperature is 110°C.

As shown in Table 9, when the temperature of the heater bed is 110 ° C., it is shown that all 3D printer filaments according to Examples 7 to 12 can be modeled up to 59 layers (wall height is 17.8 mm). rice field.

As can be seen from the results of Examples 7 to 12, by blending microfibrillated cellulose (MFC) having a relatively larger fiber diameter than the cellulose nanofibers (CNF) used in Examples 1 to 6, CNF and Similarly, it was shown that the formability of a modeled object by a 3D printer can be greatly improved. In addition, it was shown that this improvement effect can be realized only by blending about 1 wt% of CNF or MFC with respect to the resin, so that a significant reduction in raw material costs can be realized.

Although the embodiments and examples of the present invention have been described above, the embodiments and examples described above do not limit the invention according to the scope of claims. Also, it should be noted that not all combinations of features described in the embodiments and examples are essential to the means for solving the problems of the invention.

Claims

a crystalline resin;
A cellulose-containing resin composition comprising a cellulose composite in which a non-polar polymer is bound to a hydroxyl group of cellulose via a reactive group capable of reacting with the hydroxyl group.
the cellulose contains water,
2. The cellulose-containing resin according to claim 1, wherein in the cellulose composite, the nonpolar polymer is bonded to the hydroxyl group via the reactive group of the polymer aqueous emulsion, the molecular chain of which is a nonpolar polymer. Composition.
The cellulose-containing resin composition according to claim 1 or 2, wherein the crystalline resin is polypropylene.
The cellulose-containing resin according to any one of claims 1 to 3, wherein the cellulose is at least one selected from the group consisting of cellulose fibers, cellulose nanofibers (CNF), and microfibrillated cellulose (MFD). Composition.
The reactive group is at least one reactive group selected from the group consisting of a succinic anhydride group, a carbonyl group, and a carboxyl group,
the bond is an ester bond,
The cellulose according to any one of claims 1 to 4, wherein the nonpolar polymer is at least one nonpolar polymer selected from the group consisting of polypropylene, ethylene-vinyl acetate copolymer resin, and acrylic resin. containing resin composition;
The cellulose-containing resin composition according to any one of claims 1 to 5, wherein the concentration of the cellulose in the cellulose-containing resin composition exceeds 0 wt% and is 3 wt% or less.
A 3D printer filament containing the cellulose-containing resin composition according to any one of claims 1 to 6.
A product containing the cellulose-containing resin composition according to any one of claims 1 to 6.
A step of mixing a cellulose containing water and having a hydroxyl group with an aqueous emulsion of a polymer having a reactive group capable of reacting with the hydroxyl group and having a non-polar polymer molecular chain;
a step of bonding the hydroxyl group and the reactive group in the aqueous emulsion to obtain a cellulose composite;
A method for producing a cellulose-containing resin composition, comprising kneading the cellulose composite and a crystalline resin.
A 3D printer constructed using a cellulose-containing resin composition containing a crystalline resin and a cellulose composite in which a nonpolar polymer is bonded to a hydroxyl group of cellulose via a reactive group capable of reacting with the hydroxyl group A method for improving the formability of a 3D printer using filaments for 3D printers.