JP7467915B2 - Molding material and molded body - Google Patents

Description

The present invention relates to a molding material and a molded body made using this molding material.

In recent years, plant-derived plastics and biodegradable plastics have been attracting attention as a measure against marine pollution and global warming. There are three main types of plant-derived components: cellulose, hemicellulose, and lignin. Of these, cellulose is well known as a biodegradable material, but it has been reported that hemicellulose is even more biodegradable than cellulose.

Technologies that utilize cellulose as a molding material are being investigated. For example, Patent Document 1 discloses a method for manufacturing a resin molded product in which cellulose nanofibers are blended with the resin.

Patent Document 2 discloses a technique for polymerizing cellulose acetate and a fluorene-based compound to produce a material for injection molding. In addition, Patent Document 2 also proposes the use of wood flour itself, hemicellulose, and lignin.

Patent Document 3 proposes an unsaturated polyester resin that contains an unsaturated polyester and a crosslinkable monomer, and uses a material made from a wood-based material as part of the main chain of the unsaturated polyester.

Patent document 4 discloses a molded body reinforced with natural fibers. This molded body is made of a molding material obtained after plastic or thermoplastic molding of a raw material mixture containing residual moisture, and is solidified after the final molding step. The molded body contains at least one plant or animal fiber material, at least one thermoplastic or thermosetting plastic, and at least one water-binding biopolymer and/or at least one water-binding biomonomer. Patent document 4 describes that hemicellulose can be used as the plant fiber, biopolymer, and biomonomer.

JP 2018-43405 A JP 2015-86254 A JP 2008-239906 A JP 2005-506413 A

In the materials used for the resin molded products disclosed in Patent Document 1, the mixing ratio of cellulose nanofibers to polypropylene is limited to a maximum of 20% due to problems with fluidity during injection molding, and it has been difficult to increase the proportion of plant-derived materials.

In contrast, in Patent Document 2, it is possible to increase the proportion of cellulose acetate, a plant-derived material, to 70-90%, but there are issues with this, such as the high cost of fluorene itself and the insufficient light transmittance of the molded body depending on the application.

In Example 3 of Patent Document 3, a method for synthesizing a material made from lignin, cellulose, and hemicellulose in wood-based materials is disclosed. However, there is room for improvement in the moldability of the resin obtained in Patent Document 3, and the light transmittance of the molded body is also insufficient.

Patent Document 4 discloses a method of using hemicellulose as a biopolymer/biomonomer, but does not specifically disclose the use of hemicellulose, nor does it clarify its moldability, compatibility with conventional plastics, or transparency.

The problem that this invention aims to solve is to provide a molding material that can be used to form molded bodies with excellent moldability and transparency, while making effective use of hemicellulose, a plant-derived material that has hardly been used industrially.

In order to solve the above problems, the present invention has the following configuration.
[1] A molding material containing a polymer including a unit derived from a pentose derivative.
[2] The molding material according to [1], wherein the content of the pentose derivative-derived unit is 20% by mass or more based on the total mass of the molding material.
[3] The molding material according to [1] or [2], wherein the pentose derivative-derived unit is a unit derived from a monomer represented by the following formula (1):
In formula (1), R ¹ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R ^1s may be the same or different.
[4] The molding material according to [1] or [2], wherein the pentose derivative-derived unit is a unit derived from a monomer represented by the following formula (2):
In formula (2), R ¹ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R ¹ may be the same or different; R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a bromine atom, or an iodine atom; and Y ¹ represents a single bond or a linking group.
[5] The molding material according to any one of [1] to [4], wherein the pentose derivative-derived unit is a hemicellulose-derived unit.
[6] The molding material according to any one of [1] to [5], further comprising a pentose derivative.
[7] The molding material according to any one of [1] to [6], further comprising a resin component.
[8] The molding material according to any one of [1] to [7], which is for introducing metals.
[9] A molded product obtained by molding the molding material according to any one of [1] to [8].
[10] The molded article according to [9], having a total light transmittance of 80% or more.
[11] The molded article according to [9] or [10], further comprising a metal.

The present invention may also have the following configuration:

[101] A molding material comprising at least one component selected from monosaccharide or polysaccharide derivatives in which pentose is chemically modified.
[102] The molding material according to [101], wherein the monosaccharide or polysaccharide derivative in which the pentose is chemically modified has a structure represented by the following formula (1) or contains a unit derived from the structure represented by the following formula (1).
In formula (1), R ¹ each independently represents a hydrogen atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R ^1s may be the same or different.
[103] The molding material according to [101], wherein the monosaccharide or polysaccharide derivative in which the pentose is chemically modified has a structure represented by the following formula (2) or contains a unit derived from the structure represented by the following formula (2).
^R1 each independently represents a hydrogen atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R1 may be the same or different; ^R5 represents a hydrogen atom, an alkyl group, a chlorine atom, a fluorine atom, a bromine atom, or an iodine atom; ^Y1 represents a single bond or a linking group.
[104] A molded product obtained by molding the molding material according to any one of [101] to [103].
[105] A molding method comprising a step of molding the molding material according to any one of [101] to [103] to obtain a molded product.
[106] The molding method according to [105], further comprising the step of introducing a metal.
[107] The molding method according to [105] or [106], wherein at least one component selected from monosaccharide or polysaccharide derivatives having chemically modified pentoses is obtained by decomposing hemicellulose.

The present invention provides a molding material that effectively utilizes hemicellulose and can form molded articles that have excellent moldability and transparency.

The present invention will be described in detail below. The following explanation of the constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, for substituents that are not specified as substituted or unsubstituted, this means that the group may have any substituent.

(Molding material)
The molding material of the present invention relates to a molding material containing a polymer containing a pentose derivative-derived unit. The pentose derivative is at least one type selected from monosaccharide or polysaccharide derivatives in which the pentose is chemically modified. In this specification, the pentose derivative-derived unit is a unit derived from a monosaccharide or polysaccharide derivative in which the pentose is chemically modified. The molding material of the present invention may contain a monosaccharide or polysaccharide derivative in which the pentose is chemically modified.

In the molding material of the present invention, the content of the pentose derivative-derived units (sugar derivative content) is preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, and particularly preferably 40% by mass or more, based on the total mass of the molding material. The content of the pentose derivative-derived units (sugar derivative content) may be 100% by mass. By setting the content of the pentose derivative-derived units (sugar derivative content) within the above range, the biodegradability of the molded body formed from the molding material can be more effectively increased.

Here, the content of the pentose derivative-derived unit in the molding material of the present invention (sugar derivative content) is a value calculated by the following calculation formula.
Content (mass%) of pentose derivative-derived units=mass of polymer consisting of pentose derivative-derived units/mass of molding material×100
When the polymer containing the pentose derivative-derived unit is a copolymer of the pentose derivative-derived unit and another structural unit, the content of the pentose derivative-derived unit is calculated by the following formula.
Content of pentose derivative-derived units (mass%) = molecular weight of pentose derivative-derived units x average number of pentose derivative-derived units in copolymer / weight average molecular weight of molding material

The molding material of the present invention has the above-mentioned configuration and therefore has excellent moldability. Here, the moldability of the molding material can be evaluated based on the properties of the molded body after the molding material is heated and pressurized. Specifically, the moldability can be evaluated as good when a molded body without cracks and with a good appearance is obtained. In addition, the molded body formed from the molding material of the present invention also has excellent transparency. The transparency of the molded body can be determined from the total light transmittance of the molded body. Specifically, the transparency of the molded body can be evaluated as good when the total light transmittance measured by the method described in JIS K 7105 is 80% or more.

In addition, molded articles formed from the molding material of the present invention are biodegradable because they contain units derived from pentose derivatives. Such molded articles are expected to be used as materials that can suppress marine pollution and global warming.

(Pentose derivatives)
A pentose derivative (a monosaccharide or polysaccharide derivative in which pentose is chemically modified) is a pentose monosaccharide or a polysaccharide in which multiple pentoses are glycosidicly bonded, in which at least one of the hydroxyl groups is modified with a substituent. Examples of the substituent include those described below, such as an alkyl group, an acyl group, an aryl group, a phosphoryl group, and a trimethylsilyl group. In this way, by modifying a part of the hydroxyl groups of the pentose with a substituent, it is possible to weaken the hydrogen bonding strength between the hydroxyl groups, thereby improving the compatibility in the molding material and the fluidity during molding, and improving moldability.

Preferable examples of monosaccharide derivatives in which pentoses are chemically modified include xylose derivatives. In addition, preferable examples of polysaccharide derivatives in which pentoses are chemically modified include hemicellulose derivatives and xylooligosaccharide derivatives, with xylooligosaccharide derivatives being preferred.

It is also preferable that the pentose derivative is a material derived from hemicellulose. In other words, it is preferable that the pentose derivative-derived unit is a unit derived from hemicellulose. By obtaining a pentose derivative from a material derived from hemicellulose, it is possible to effectively utilize hemicellulose. In addition, hemicellulose is known to be highly biodegradable, and since both cellulose and cellulose acetate are biodegradable, the biodegradability can be more effectively increased by using a material derived from hemicellulose.

The pentose derivative-derived units are preferably units derived from a monomer represented by the following formula (1) or (2). In other words, the polymer contained in the molding material preferably contains units derived from a monomer represented by the following formula (1) or (2).

In formula (1), R ^1s each independently represent a hydrogen atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R ^1s may be the same or different, provided that at least one of R ^1s is an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group.

In formula (2), ^R1 each independently represents a hydrogen atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of ^R1 may be the same or different. ^R5 represents a hydrogen atom, an alkyl group, a chlorine atom, a fluorine atom, a bromine atom, or an iodine atom. ^Y1 represents a single bond or a linking group.

The polymer containing a pentose derivative-derived unit may be a sugar polymer having a side chain. Here, the sugar polymer may be one in which a sugar chain constitutes the main chain of the polymer, or another component other than the sugar chain may constitute the main chain of the polymer. When another component other than the sugar constitutes the main chain of the polymer, the sugar or sugar chain constitutes the side chain of the polymer. In addition, when the sugar polymer has sugar chains in the main chain and the side chain, either the pentose in the main chain or the side chain may be chemically modified.

When a component other than sugar constitutes the main chain of the polymer, the unit derived from a pentose derivative is preferably a unit represented by the following formula (3).

In formula (3), R ¹ 's each independently represent a hydrogen atom, an alkyl group, an acyl group, an aryl group, a phosphoryl group, or a trimethylsilyl group, the alkyl group including a sugar derivative group, and multiple R ¹ 's may be the same or different;
R' represents a hydrogen atom, --OR ¹ , an amino group or --NR ¹ ₂ .
R″ represents a hydrogen atom or —OR ¹ .
In addition, R ¹ in R′ and R″ is the same as R ¹ in formula (3), and the preferred range is also the same.
^R5 represents a hydrogen atom, an alkyl group, a chlorine atom, a fluorine atom, a bromine atom, or an iodine atom, and a plurality of ^R5 may be the same or different. Among them, ^R5 is preferably a hydrogen atom, an alkyl group, a fluorine atom, a bromine atom, or an iodine atom.
X ¹ and Y ¹ each independently represent a single bond or a linking group, and a plurality of X ¹ s may be the same or different, and a plurality of Y ¹ s may be the same or different.

When the sugar chain constitutes the main chain of the polymer, the unit derived from the pentose derivative is preferably a unit represented by the following formula (4).

In formula (4), R ²⁰¹ each independently represents a hydrogen atom, an alkyl group, an acyl group, an aryl group, a phosphoryl group, or a trimethylsilyl group, and a plurality of R ²⁰¹ may be the same or different.
R' represents a hydrogen atom, --OR ¹ , an amino group or --NR ¹ ₂ .
R″ represents a hydrogen atom or —OR ¹ .
In addition, R ¹ in R′ and R″ is the same as R ¹ in formula (3), and the preferred range is also the same.
The * symbol represents a bonding site in place of R ²⁰¹ with any one of the oxygen atoms to which R ²⁰¹ is bonded.

When the pentose derivative-derived unit is a unit represented by the above formula (3), in formula (3), R ¹ each independently represents a hydrogen atom, an alkyl group, an acyl group, an aryl group, a phosphoryl group, or a trimethylsilyl group. It is preferable that at least one of R ¹ is an alkyl group, an acyl group, an aryl group, a phosphoryl group, or a trimethylsilyl group. The alkyl group in R ¹ may be an alkyl group having a substituent, and such an alkyl group includes a sugar derivative group, so that the sugar portion (sugar derivative portion) of formula (3) may further have a linear or branched sugar derivative portion. Among them, it is preferable that R ¹ each independently represents a hydrogen atom or an acyl group having 1 to 3 carbon atoms. It is preferable that a plurality of R 1s are the same or different.

In the above formula (3), when R ¹ is an alkyl group or an acyl group, the number of carbon atoms can be appropriately selected depending on the purpose. For example, the number of carbon atoms is preferably 1 or more, and is preferably 200 or less, more preferably 100 or less, even more preferably 20 or less, and particularly preferably 4 or less.

Specific examples of R ¹ in the above formula (3) include acyl groups such as acetyl, propanoyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, hexanoyl, octanoyl, chloroacetyl, trifluoroacetyl, cyclopentanecarbonyl, cyclohexanecarbonyl, benzoyl, methoxybenzoyl, and chlorobenzoyl; and alkyl groups such as methyl, ethyl, propyl, butyl, and t-butyl. Among these, methyl, ethyl, acetyl, propanoyl, butyryl, isobutyryl, and benzoyl are preferred, with acetyl and propanoyl being particularly preferred.

In formula (3), R' represents a hydrogen atom, ^-OR1 , an amino group, _or ^-NR12 . Specific examples of ^R1 include the same as the specific examples of ^R1 in formula ( _{3 )} above. Preferred structures of R' are -H, -OH, -OAc, _-OCOC2H5 , _-OCOC6H5 , _-NH2 , -NHCOOH, and _-NHCOCH3 , more preferred structures of R' are -H, -OH, _-OAc , _-OCOC2H5 , _{and -NH2 ,} and particularly preferred structures of R' are -OH, -OAc, and _-OCOC2H5 .

In formula (3), R" represents a hydrogen atom or ^-OR1 . Specific examples of ^R1 include the same as the specific examples of ^R1 in formula (3) above. Preferred structures of R" are -H, _-OAc , and _-OCOC2H5 , and more preferred structures of R" are -H, -OAc, and _{-OCOC2H5 .}

In formula (3), ^R5 represents a hydrogen atom, an alkyl group, a chlorine atom, a fluorine atom, a bromine atom, or an iodine atom, and a plurality of R5 may be the same or different. Among them, ^R5 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group.

In formula (3), X ¹ and Y ¹ each independently represent a single bond or a linking group, and a plurality of X ¹ s may be the same or different, and a plurality of Y ¹ s may be the same or different.
When ^X1 is a linking group, examples of ^X1 include groups containing an alkylene group, -O-, _-NH2- , a carbonyl group, etc., and ^X1 is preferably a single bond or an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms.
When ^Y1 is a linking group, examples of ^Y1 include groups including an alkylene group, a phenylene group, -O-, -C(=O)O-, etc. ^Y1 may be a linking group that combines these groups. Among them, ^Y1 is preferably a linking group (a) to (e) shown below.

In the linking groups (a) to (e), the * symbol indicates the bonding site with the main chain, and the * symbol indicates the bonding site with the sugar unit of the side chain.

In this specification, when R ¹ in formula (3) is an alkyl group, the alkyl group may be an alkyl group having a substituent, and such an alkyl group includes a sugar derivative group. Therefore, the sugar portion (sugar derivative portion) of formula (3) may further have a straight-chain or branched-chain sugar derivative portion. In other words, the pentose derivative-derived unit may be a unit represented by formula (3').

In formula (3'), ^R1 , ^R5 , R', R'', ^X1 and ^Y1 are the same as ^R1 , ^R5 , R', R'', ^X1 and ^Y1 in formula (3). r is 2 or more and 1500 or less. In formula (3'), the mark * represents a bonding site with any one of ^R1 when r is 2 or more, or represents a bonding site with any one of the oxygen atoms to which ^R1 is bonded in place of ^R1 .

In addition, r in formula (3') represents the degree of polymerization of the sugar derivative portion. The average degree of polymerization of the sugar derivative portion can be calculated by the following measurement method. First, the solution containing the pentose derivative is kept at 50°C and centrifuged at 15,000 rpm for 15 minutes to remove insoluble matter. Then, the total sugar amount and the amount of reducing sugar (both converted into xylose) of the supernatant are measured. The average degree of polymerization is calculated by dividing the total sugar amount by the amount of reducing sugar. In addition, if the above measurement method cannot be adopted, gel permeation chromatography, size exclusion chromatography, light scattering method, viscosity method, terminal group quantification method, sedimentation velocity method, MULDI-TOF-MS method, structural analysis method by NMR, etc. may be adopted.

When the average degree of polymerization of a sugar derivative is measured after polymer synthesis, the integral value of the peak (around 3.3-5.5 ppm) derived from ^the sugar chain and the integral value of the peak derived from other components of the pentose derivative are calculated by 1H-NMR, and the average degree of polymerization is calculated from the ratio of the integral values. When R ¹ in formula (3') is not a hydrogen atom, the integral value of the peak derived from -OR ¹ group can be used instead of the peak derived from the sugar chain (however, in this case, R ¹ of -OR ¹ group is not a sugar chain).

When polymerizing a polymer containing the pentose derivative-derived unit described in formula (3), it may be a homopolymer, or it may be a copolymer that is polymerized by mixing with other known monomer materials. There is no particular limit to known monomer materials, but methyl methacrylate, styrene, lactic acid, propylene, terephthalic acid, ethylene glycol, etc. can also be used.

When the pentose derivative-derived unit is a unit represented by the above formula (4), in formula (4), R ²⁰¹ each independently represents a hydrogen atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R ²⁰¹ may be the same or different. At least one of R ²⁰¹ is preferably an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group.

In formula (4), the preferred ranges of R ²⁰¹ , R', and R'' are the same as the preferred ranges of R ¹ , R', and R'' in formula (3).

The polymer contained in the molding material of the present invention may be a copolymer containing structural units of formula (3) and formula (4). The polymer contained in the molding material of the present invention may also contain other structural units in addition to the structural units of formula (3) and/or formula (4).

The molding material of the present invention contains a polymer containing a pentose derivative-derived unit as described above. The weight-average molecular weight of the polymer is preferably 150 or more, more preferably 200 or more, and even more preferably 300 or more. The weight-average molecular weight of the polymer is preferably 2,000,000 or less, more preferably 1,000,000 or less, and even more preferably 800,000 or less. The weight-average molecular weight of the polymer is a value measured by gel permeation chromatography (GPC) in terms of polystyrene.

(Resin Component)
The molding material of the present invention may contain a resin component in addition to the polymer containing a unit derived from a pentose derivative. The resin component is not particularly limited, but may include PMMA, PC, PS, polylactic acid, polypropylene, PET, PTFE, polyamide, PFA, etc. In the molding material of the present invention, a chemically modified pentose is used, so that the compatibility with the resin component is dramatically improved compared to monosaccharides or polysaccharides made of a non-chemically modified pentose.

The resin component may be included as a copolymerization component constituting a polymer containing a pentose derivative-derived unit. In this case, a polymer is formed by copolymerizing the pentose derivative-derived unit with a unit derived from a monomer constituting the resin described above. In this way, the resin component may be included as a copolymerization component constituting a polymer containing a pentose derivative-derived unit. Such a copolymer may be a random copolymer or a block copolymer.

The resin component may also be a polymer that is added separately from the polymer containing pentose derivative-derived units. In such a case, the resin component may be added as a plastic material. Examples of the plastic material include materials similar to the resin component described above. When the resin component is a polymer that is added separately from the polymer containing pentose derivative-derived units, the polymer containing pentose derivative-derived units and the polymer consisting of the resin component are melt-mixed.

(Optional ingredients)
In addition to the above components, the molding material of the present invention may contain a crosslinking agent, a polymerization initiator, an additive for improving compatibility, a colorant, a thickener, a shrinkage reducing agent, a reinforcing material, an inorganic filler, etc. The crosslinking agent or polymerization initiator may be one that crosslinks or polymerizes a group that substitutes a hydroxyl group of a monosaccharide or polysaccharide, or may be one that crosslinks or polymerizes a material other than a derivative of a monosaccharide or polysaccharide contained in the molding material.

In addition, the molding material of the present invention may contain a pentose derivative as a monomer component in addition to the polymer containing a unit derived from a pentose derivative. By including a pentose derivative as a monomer component, the moldability of the molding material can be improved.

In the process of forming a molded body from the molding material of the present invention, a metal component may be introduced. A molded body with a metal component introduced therein can exhibit electrical conductivity, and is therefore preferably used in applications where electrical conductivity is required. In this way, the molding material of the present invention may be a material for introducing a metal.

(Method of synthesizing polymers containing units derived from pentose derivatives)
The polymer containing the pentose derivative-derived unit can be synthesized by known polymerization methods such as living radical polymerization, living anionic polymerization, and atom transfer radical polymerization. For example, in the case of living radical polymerization, a polymer can be obtained by reacting a monomer such as a pentose derivative with a polymerization initiator such as AIBN (α,α'-azobisisobutyronitrile). In the case of living anionic polymerization, a polymer can be obtained by reacting a monomer with butyllithium in the presence of lithium chloride. Note that, although an example of synthesis using living anionic polymerization is shown in this example, the present invention is not limited thereto, and the polymer can be appropriately synthesized by each of the above synthesis methods or known synthesis methods.

(Method of Extracting Pentose Materials)
The pentose material used in the synthesis of the polymer containing pentose derivative-derived units may be obtained by synthesis, or may be obtained by combining a step of extraction from woody plant- or herbaceous plant-derived material. When a method of extraction from lignocellulose derived from woody plant or herbaceous plant is adopted, the extraction method described in JP 2012-100546 A or the like can be used. Xylan can be extracted, for example, by the method disclosed in JP 2012-180424 A.

Chemical Modification of Pentose Materials
The pentose derivative is preferably used after modifying the OH group of the pentose material obtained by the above extraction method, etc. by acetylation, halogenation, etc. For example, when an acetyl group is introduced, an acetylated pentose derivative can be obtained by reacting the pentose material with acetic anhydride.

(Molded body)
The present invention also relates to a molded body obtained by molding the above-mentioned molding material. In particular, the molding material is preferably the above-mentioned molding material molded under heat and pressure. The molded body may also be a molded body obtained by curing the above-mentioned molding material by irradiating it with an active energy source.

The total light transmittance of the molded article of the present invention is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. As such, the molded article of the present invention has excellent transparency and is therefore preferably used as an optical component.

The molded product of the present invention may further contain the optional components and metals described above. The metal contained in the molded product is introduced in the step of introducing the metal described below. The molded product with the metal introduced therein can exhibit electrical conductivity, and is therefore preferably used in applications where electrical conductivity is required.

Applications of the molded body include, for example, housings for electronic devices and home appliances, reinforcing materials, civil engineering and building material parts, interior parts, automobile and motorcycle parts, aircraft parts, railway vehicle parts, daily necessities, packaging materials, and the like, among which the molded body is particularly suitable for disposable applications. It is desirable that the molded body of the present invention does not leak into the natural environment, but even if it does leak out, it will decompose in the natural environment, thereby reducing the burden on the environment.

(Molding method)
The molding method of the molded article of the present invention is not particularly limited, and examples thereof include injection molding, extrusion molding, blow molding, vacuum molding, pressure molding, cast molding, foam molding, powder molding, photomolding, compression molding, etc. Among these, the molding method is preferably injection molding, extrusion molding, foam molding, or powder molding.

When forming the molded body of the present invention, molding by photopolymerization can also be performed. In this case, it is preferable to use a photopolymerization material as the above-mentioned molding material. When forming a molded body by photopolymerization, for example, the molding material of the present invention is poured into a mold processed with a concave mold or a fine pattern, and a molded body can be obtained by irradiating it with light. In addition, a substrate can be coated with a desired thickness, and then a molded body coated with the molding material can be obtained by irradiating it with light. Alternatively, it can be applied to so-called nanoimprint technology in which the molding material is coated on the base material to form an uncured resin film, and the resin film is photopolymerized while pressing a mold against the resin film. When using the molding material of the present invention for nanoimprinting, it is preferable to add a monomer component of a pentose derivative to reduce the viscosity of the molding material before curing. Alternatively, it is also preferable to add a monosaccharide derivative or an oligosaccharide derivative other than the pentose derivative. The base material for coating is not particularly limited, but materials such as PET, PP, PE, PS, PC, PMMA, COP (cycloolefin polymer), polyamide, cellulose nanofiber, silicon, and quartz can be used.

(Metal introduction step)
When a molded body is formed using the molding material of the present invention, it is also preferable to provide a step of introducing a metal after molding. By introducing a metal, the strength and electrical conductivity of the molded body can be increased.

Methods for introducing metals include mixing the metal material into the molding material itself or coordinating the metal, but the metal can also be introduced after forming the molded body. Specific examples include metal impregnation methods such as CVD (chemical vapor deposition), sputtering (vacuum deposition), ALD (atomic layer deposition), and SIS (sequential infiltration synthesis). Among these, the step of introducing the metal is preferably performed after molding the molding material, and the metal impregnation method of impregnating the molded body with a metal gas is particularly preferred because the metal penetrates not only the surface of the molded body but also the inside. In this case, the step of introducing the metal may be performed on the entire molded body, or the metal can be introduced by selecting the part of the molded body to which the metal is to be introduced.

Metals introduced in the metal introduction process include Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Pd, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, etc. Such a process can be carried out, for example, by the method described in Journal of Photopolymer Science and Technology Volume 29, Number 5 (2016) 653-657.

The features of the present invention are explained in more detail below with reference to the following examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

[Preparation of sugar]
Xylooligosaccharides and xylose were extracted from wood pulp with reference to JP 2012-100546 A.

[Example 1]
(Synthesis of acetyl sugar methacrylate 1)
1 kg of xylose was added to a mixed solution of 12 kg of acetic anhydride and 16 kg of acetic acid, and stirred at 30°C for 2 hours. Approximately 5 times the amount of cold water as the solution was slowly added while stirring, and after stirring for 2 hours, the solution was left to stand overnight. 60 g of ethylenediamine and 70 g of acetic acid were added to 20 L of THF in a flask, and the solution was cooled to 0°C. 1 kg of precipitated crystals was added to the solution, and stirred for 4 hours. This was poured into 50 L of cold water and extracted twice with dichloromethane. 1 kg of the obtained extract, 15 L of dichloromethane, and 240 g of triethylamine were placed in a flask and cooled to -30°C. Next, 140 g of methacryloyl chloride was added and stirred for 2 hours. This was poured into 15 L of cold water, extracted twice with dichloromethane, and the solvent was concentrated to obtain 810 g of acetyl sugar methacrylate 1. The structure of the obtained acetyl sugar methacrylate 1 is as shown in the following formula (6).

(Synthesis of acetyl sugar methacrylate polymer 1)
500 mL of tetrahydrofuran and 92 g of a 2.6% by mass THF solution of lithium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to the flask, and the mixture was cooled to −78° C. under an argon atmosphere. 13 g of a 15.4% by mass hexane solution of n-butyllithium (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred for 5 minutes, after which dehydration and degassing treatment were performed. Next, acetyl sugar methacrylate 1 (300 g) was added and stirred for 30 minutes. Then, 10 g of methanol was added to stop the reaction, and acetyl sugar methacrylate polymer 1 was obtained. The polymerization degree of acetyl sugar methacrylate was 350. The weight average molecular weight of acetyl sugar methacrylate polymer 1 was 34,000. The obtained acetyl sugar methacrylate polymer 1 was used as a molding material.

[Example 2]
(Synthesis of acetyl sugar methacrylate 2)
Acetyl sugar methacrylate 2 was synthesized in the same manner as in the synthesis of acetyl sugar methacrylate 1 in Example 1 (synthesis of acetyl sugar methacrylate 1), except that xylose was replaced with a xylooligosaccharide having an average degree of polymerization of 3.

(Synthesis of acetyl sugar methacrylate polymer 2)
500 mL of tetrahydrofuran and 92 g of a 2.6% by mass THF solution of lithium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to the flask, and the mixture was cooled to -78°C under an argon atmosphere. 13 g of a 15.4% by mass hexane solution of n-butyllithium (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred for 5 minutes, after which it was dehydrated and degassed. Next, acetyl sugar methacrylate 2 (300 g) was added and stirred for 30 minutes. Thereafter, 10 g of methanol was added to stop the reaction, and acetyl sugar methacrylate polymer 2 was obtained.

(Synthesis of polylactic acid)
900 g of L-lactic acid was added to a flask, and after degassing, 4 L of dehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd.) and 7 mL of tin(II) 2-ethylhexanoate (manufactured by Sigma-Aldrich Co.) were added under an argon atmosphere, and the mixture was stirred for 24 hours at 90° C. After the reaction, the mixture was cooled to room temperature, and 5 L of methanol was added to terminate the reaction, yielding polylactic acid.

(Synthesis of polylactic acid-acetyl sugar methacrylate diblock copolymer)
The polylactic acid-acetyl sugar methacrylate two-block copolymer was synthesized with reference to Macromolecules Vol. 36, No. 6, 2003. First, 50 g of acetyl sugar methacrylate polymer 2 and 50 g of polylactic acid were placed in 1 L of DMF, and 1 g of _NaCNBH3 was added as a reducing agent. The mixture was stirred at 60°C for 7 days, during which ₁ g of NaCNBH3 was added every day. The mixture was then cooled to room temperature, and 5 L of water was added to precipitate. The precipitate was filtered and washed several times with cold water to remove excess acetyl sugar. The filtered solid was then vacuum dried to obtain a polylactic acid-acetyl sugar methacrylate two-block copolymer. The structure of the resulting block copolymer is shown in the following formula (7).

In formula (7), p = 104, q = 156, and r = 1. Here, p, q, and r indicate the average values in the obtained block copolymer. The weight-average molecular weight of the obtained polylactic acid-acetyl sugar methacrylate two-block copolymer was 32,000. This polylactic acid-acetyl sugar methacrylate two-block copolymer was used as the molding material.

[Example 3]
(Synthesis of acetyl sugar)
1 kg of xylooligosaccharide (average sugar chain length 8) was added to a mixed solution of 12 kg of acetic anhydride and 15 kg of pyridine, and stirred at 30°C for 17 hours. Approximately 5 times the amount of cold water as the solution was slowly added while stirring, and the mixture was stirred for 30 minutes to synthesize acetyl sugar, which is a xylose acetyl derivative. 6 g of PMMA (Sigma-Aldrich, weight average molecular weight 350,000) was mixed with 4 g of the obtained acetyl sugar, which was an absolute dry mass, to prepare a molding material.

[Example 4]
10 g of acetyl sugar methacrylate 1 synthesized in Example 1 (Synthesis of acetyl sugar methacrylate 1), 0.3 g of IRGACURE369 (manufactured by Ciba Specialty Chemicals) as a polymerization initiator, 3 g of Light Ester M (manufactured by Kyoeisha Chemical Co., Ltd.), and 2 g of pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) were mixed, and the polymer obtained by irradiating with a xenon lamp was used as a molding material.

[Comparative Example 1]
Powdered cellulose (Sigma-Aldrich) was used as the molding material.

[Comparative Example 2]
A molding material was prepared by mixing 4 g of powdered cellulose (Sigma-Aldrich Corporation, absolute dry weight) with 6 g of PMMA (Sigma-Aldrich Corporation, weight average molecular weight 350,000).

[Measurement and Evaluation]
<Content of pentose derivative-derived units>
The content of the pentose derivative-derived unit in the molding material was calculated as follows.
Content (mass%) of pentose derivative-derived units=mass of polymer consisting of pentose derivative-derived units/mass of molding material×100
When the pentose derivative-derived unit forms a copolymer with another structural unit, the content of the pentose derivative-derived unit was calculated as follows.
Content of pentose derivative-derived units (mass %)=molecular weight of pentose derivative-derived units×average number of pentose derivative-derived units in copolymer/weight average molecular weight of molding material In the above formula, the molecular weight of the pentose derivative-derived units, the average number of pentose derivative-derived units in the copolymer, and the weight average molecular weight of the molding material were calculated as follows: The average degree of polymerization of the sugar derivative moiety in the pentose derivative-derived units was calculated using ^1H -NMR, and the molecular weight of the pentose derivative-derived units was calculated from the calculated average degree of polymerization of the pentose derivatives.
The weight average molecular weight of the molding material was measured by gel permeation chromatography (GPC).
GPC column: Shode x K-806M/K-802 combined column (Showa Denko K.K.)
Column temperature: 40°C
Mobile phase: chloroform Detector: RI
The average content of units derived from pentose derivatives in the copolymer was calculated from the values of ¹ H-NMR and GPC.
Average number of pentose derivative-derived units in copolymer=(number ratio of pentose derivative-derived units×number average molecular weight of molding material)/{(molecular weight of pentose derivative-derived units×number ratio of pentose derivative-derived units)+(number average molecular weight of other structural units×number ratio of other structural units)}

<Moldability>
(Thermoforming)
The molding materials obtained in the examples and comparative examples were thermoformed to confirm moldability. Specifically, 2 g of the molding materials obtained in the examples and comparative examples were placed in a silicon rubber mold made to have a recess of 10 mm x 20 mm x 2 mm. Next, the molding material was melted by reducing the pressure inside the rubber mold and heating the mold from the outside to 160 to 180°C with a lamp. After that, the molding material was cooled by air cooling for 1 hour and removed from the mold to obtain a molded body. The moldability was evaluated from the appearance of the molded body according to the following evaluation criteria.
◯: No cracks were found on the molded product by visual inspection, and moldability was good.
×: Cracks were visually observed in the molded product, and there was a problem with moldability.

<Transparency>
In the evaluation of moldability, the total light transmittance of the molded article was measured by the method described in JIS K 7105.

<Conductivity>
The molded body produced in the evaluation of moldability was placed in an ALD (atomic layer deposition apparatus: SUNALE R-100B manufactured by PICUSAN), and Al( _CH3 ) ₃ gas was introduced at 95°C, followed by water vapor. This operation was repeated three times to introduce _Al2O3 into the molded body. The molded body after the introduction _{of Al2O3 was} subjected to EDX analysis (energy dispersive X-ray analysis) using an electron microscope JSM7800F (manufactured by JEOL Ltd.) to calculate the ratio of the Al component, and the electrical conductivity was evaluated according to the following evaluation criteria.
◯: The ratio of the Al component is 5 atom % or more, and the molded body has electrical conductivity.
×: The ratio of the Al component is less than 5 atom %, and the molded body has no electrical conductivity.

<Photoformability>
In Example 4, the moldability by photomolding was further confirmed. The molding material of Example 4 was applied to a 0.1 μm thick PET film to a thickness of 200 nm, and a quartz template mold in which a hole with a diameter of 100 nm was formed was pressed against the film, irradiated with a xenon flash lamp, and removed from the mold. When the surface of the PET film was observed with an SEM, it was confirmed that a pillar structure (molded body) with a diameter of 100 nm was formed by inverting the hole type of the quartz template. The transfer structure of the quartz template obtained in Example 4 had no defects and was optically transparent.

As described above, the molding material of the example had excellent moldability and transparency. In the molded body obtained in the example, the occurrence of structural defects such as cracks was suppressed, and strength was expected to be exhibited. In addition, since it has optical transparency, it can be used as an optical component. Furthermore, since it is easy to introduce metal, it can also be used as a conductive or antistatic part. In addition, the molded body produced using the molding material of the example is biodegradable because it contains components derived from pentose derivatives.

Claims (9)

A molding method comprising a step of molding a molded body from a molding material containing a polymer including a pentose derivative-derived unit,
The pentose derivative-derived unit is a unit derived from a monomer represented by the following formula (1) or (2):
The molding material further contains a pentose derivative as a monomer component,
a molding method in which, in the step of molding the molded body, the molded body is molded by at least one method selected from the group consisting of injection molding, extrusion molding, blow molding, vacuum molding, cast molding, foam molding, powder molding, and photo molding;
In formula (1), R ¹ 's each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R ¹ 's may be the same or different; provided that at least one of R ¹ 's is an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group;
In formula (2), R ¹ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group, and a plurality of R ¹ may be the same or different; R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a bromine atom, or an iodine atom; and Y ¹ represents a single bond or a linking group. The molding method according to claim 1, wherein the content of the pentose derivative-derived units is 20% by mass or more based on the total mass of the molding material. The molding method according to claim 1 or 2 , wherein the molding material further contains a resin component other than the polymer containing the pentose derivative-derived unit. The molding method according to any one of claims 1 to 3 , further comprising a metal introducing step. The molding method according to any one of claims 1 to 4 , wherein the molded body has a total light transmittance of 80% or more. A molding method comprising a step of molding a molded body from a molding material containing a polymer including a pentose derivative-derived unit,
The pentose derivative-derived unit is a unit derived from a monomer represented by the following formula (1) or (2):
In the step of molding the molded body, the molded body is molded by at least one method selected from the group consisting of injection molding, extrusion molding, blow molding, vacuum molding, cast molding, foam molding, powder molding, and photo molding;
the forming method further comprising a metal introduction step;
In formula (1), R ¹ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group; ¹ may be the same or different; provided that R ¹ at least one of is an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group;
In formula (2), R ¹ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group, an acyl group, an aryl group, a trimethylsilyl group, or a phosphoryl group; ¹ may be the same or different; R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a bromine atom or an iodine atom; Y ¹ represents a single bond or a linking group. The molding method according to claim 6 , wherein the content of the pentose derivative-derived units is 20% by mass or more based on the total mass of the molding material. The molding method according to claim 6 or 7, wherein the molding material further contains a resin component other than the polymer containing a unit derived from a pentose derivative. The molding method according to any one of claims 6 to 8, wherein the molded body has a total light transmittance of 80% or more.