WO2025084183A1 - Polysaccharide-derived thermoplastic resin having high heat resistance and low dielectric constant - Google Patents

Abstract

Provided is a novel polysaccharide derivative which has a structure in which a plurality of monosaccharide units are polymerized, wherein a portion or the entirety of hydrogen atoms of hydroxyl groups in a portion or the entirety of the monosaccharide units is substituted with either -C(O)-(CH₂)_m-R¹ (in the formula, R¹s may be the same as or different from each other and are each a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0-6) or -(CH₂)_m-R² (in the formula, R²s may be the same as or different from each other and are each a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and m is 0-6).

Description

Polysaccharide-derived thermoplastic resin with high heat resistance and low dielectric constant

The present invention relates to a polysaccharide-derived thermoplastic resin that has high heat resistance and low dielectric constant.

In recent years, the increasing performance and functionality of electrical and electronic devices has created a need for high-speed information communication. For example, the spread of high-volume, high-speed communications such as the fifth-generation communications system (5G) and millimeter-wave radar for automotive ADAS (advanced driving systems) has led to the signals of communications devices becoming increasingly high-frequency.

　Traditionally, epoxy resins and polyimides have been used as circuit board materials from the perspective of heat resistance. However, these circuit board materials have a high relative dielectric constant, which increases transmission loss in high-frequency applications, causing problems such as signal attenuation and heat generation. In recent years, therefore, resins with excellent low dielectric properties have been developed. For example, polyphenylene ether and fluorine-containing resins are used. However, these resins are all plastics made from petroleum. From the perspective of reducing carbon dioxide emissions, it is necessary to switch to plastics made from biomass (biomass plastics). Furthermore, the use of fluorine-containing resins is being restricted due to their environmental impact.

Natural polysaccharides that have been used in biomass plastics to date include plant-derived polysaccharides such as cellulose (β-1,4-glucan), starch (α-1,4-glucan), and xylan (β-1,4-xylan), as well as polysaccharides produced by microorganisms such as curdlan (β-1,3-glucan) and dextran (α-1,6-glucan), and their derivatives.

Patent Document 1 discloses an esterified α1,3-glucan derivative into which a branched alkyl acyl group has been introduced. It states that the glass transition point of a film formed from a branched esterified α1,3-glucan derivative is higher than that of a film formed from a derivative into which a linear ester chain with the same number of carbon atoms has been introduced.

Non-Patent Document 1 discloses a paramylon ester derivative obtained by esterifying the hydroxyl groups of the glucose units of paramylon, a linear β1,3-glucan, with linear or branched fatty acids having 3 to 7 carbon atoms.

WO2020/241421

FY2021 Ministry of the Environment commissioned project: FY2021 Demonstration project for establishing a resource circulation system for plastics, etc. to support a carbon-free society (Demonstration project for application of polysaccharide-based high-performance bioplastics to electronic devices and home equipment (interior) products and a recycling system) Commissioned project results report, February 2022, NEC Corporation, [Retrieved September 19, 2023], Internet https://www.env.go.jp/content/000038658.pdf

Currently, it is difficult for biomass plastics to achieve both the high thermal stability and low dielectric constant required for circuit boards.

One of the problems that the present invention aims to solve is to provide a polysaccharide derivative that is highly heat resistant and has a low dielectric constant, while using high molecular weight polysaccharides as the raw material.

Another problem to be solved by the present invention is to provide a polysaccharide derivative that has high heat resistance, a low dielectric constant, and an even lower dielectric tangent.

　Conventional resins known for their high heat resistance and low dielectric constant are all aromatic polymers, fluororesins, cycloolefins, and crosslinked polymers. However, the present inventors conducted extensive research to solve the above problems, and as a result, they obtained a glucan derivative with high heat resistance and low dielectric constant equivalent to or exceeding those resins by introducing a side chain having a cyclic hydrocarbon group to the hydroxyl group of the glucose unit of a polysaccharide. They found that such a glucan derivative has a significantly higher glass transition point (which can be used interchangeably with "glass transition temperature" in this specification) than a glucan derivative having a linear ester chain or a branched ester chain of the same carbon number, and combines high heat resistance and low dielectric constant. The present inventors further found that by introducing a structure in which the structural unit of a polysaccharide does not have a primary hydroxyl group in the side chain, it is possible to combine high heat resistance and low dielectric constant, and further reduce the dielectric loss tangent of the polysaccharide derivative.

The present invention includes the following embodiments:

Item 1.
A polysaccharide derivative having a structure in which a plurality of monosaccharide units are polymerized, in which some or all of the hydrogen atoms of the hydroxyl groups of some or all of the monosaccharide units in the plurality of monosaccharide units are substituted with -C(O)-( _CH2 ) _m - ^R1 (1) (wherein each ^R1 may be the same or different and is a substituted or unsubstituted straight-chain or branched-chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6) or -( _CH2 ) _m - ^R2 (2) (wherein each ^R2 may be the same or different and is a substituted or unsubstituted straight-chain or branched-chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6), which is any of the following (i) to (iii):

(i) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group. (ii) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. (iii) A glucan derivative in which the monosaccharide unit is xylose, and each R Item 2. A xylan derivative having no primary hydroxyl group in a side chain, wherein R ¹ may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group.
Item 2. A polysaccharide derivative according to Item 1, which is a glucan derivative having a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and in which some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ (1) (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and m is 0 to 6) or -(CH ₂ ) _m -R ² (2) (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and m is 0 to 6).

Item 3.
Item 3. The polysaccharide derivative according to Item 2, wherein the glycosidic bond comprises an α-1,3-glycosidic bond, an α-1,6-glycosidic bond, a β-1,3-glycosidic bond, or a β-1,4-glycosidic bond.

Item 4.
Item 2. The polysaccharide derivative according to Item 1, wherein the cyclic hydrocarbon group of R ¹ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Item 5.
Item 2. The polysaccharide derivative according to Item 1, wherein the alicyclic hydrocarbon group is a monocyclic alicyclic hydrocarbon group having a 3- to 12-membered ring.

Item 6.
Item 2. The polysaccharide derivative according to item 1, which is a crystal.

Item 7.
Item 7. The polysaccharide derivative according to any one of Items 1 to 6, which has a glass transition point of 200° C. or higher and a dielectric constant of 3.0 or lower.

Item 8.
A grafted glucan derivative in which a second glucan derivative different from the first glucan derivative is grafted to a first glucan derivative, each of the first glucan derivative and the second glucan derivative has a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units of the first glucan derivative and the second glucan derivative are substituted with -C(O)-(CH ₂ ) _m -R ¹ (1) (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6) or -(CH ₂ ) _m -R ² (2) (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6).

Item 9.
Item 8. A resin composition comprising one or more of the polysaccharide derivatives according to any one of items 1 to 7 or the glucan derivatives according to item 8.

Item 10.
Item 10. A molded article obtained by molding the polysaccharide derivative according to any one of items 1 to 7, the glucan derivative according to item 8, or the resin composition according to item 9.

Item 11.
Item 11. The molded article according to item 10, which is a film.

Item 12.
Item 10. A circuit board material comprising the glucan derivative according to any one of items 1 to 7, the glucan derivative according to item 8, or the resin composition according to item 9.

According to one effect of the present invention, the polysaccharide derivative of the present invention has higher heat resistance than a polysaccharide derivative having a linear ester chain or a branched ester chain with the same number of carbon atoms introduced therein, and can combine high heat resistance and a low dielectric constant. According to another effect of the present invention, the polysaccharide derivative of the present invention has higher heat resistance than a glucan derivative having a linear ester chain or a branched ester chain with the same number of carbon atoms introduced therein, and can combine high heat resistance and a low dielectric constant, and can have a low dielectric tangent.

Graph showing the relationship between the glass transition temperature and the dielectric constant at 1 GHz for various glucan derivatives and known thermoplastic resins: (A) β-1,4-glucan ester, (B) β-1,3-glucan ester, (C) α-1,3-glucan ester. Graph showing the relationship between the glass transition temperature and the dielectric constant at 1 GHz for a glucan derivative having six carbon atoms in its side chain (black circles: before heating, white circles: after heating) and a known thermoplastic resin: (A) β-1,4-glucan ester, (B) β-1,3-glucan ester, (C) α-1,3-glucan ester. The black plots are the values for cast films that were not heat-treated, and the white plots are the values after heat treatment for 1 hour at a temperature midway between the glass transition temperature and the melting point of each derivative. (A) Esterification of α-1,6-glucan, (B) ¹ H NMR spectrum of α-1,6-glucan-CH. Dielectric constant Dk (solid line) and dielectric tangent Df (dashed line) of α-1,3-glucan-CH and α-1,6-glucan-CH Dielectric constant Dk and dielectric loss tangent Df of α-1,3-glucan-CH (circles), α-1,3-glucan-CH after heat treatment (squares), and α-1,6-glucan-CH (triangles) compared with polyimide, liquid crystal polymer, and fluororesin Dielectric constant Dk (solid line) and dielectric tangent Df (dashed line) of cellulose-Pr, α-1,6-glucan-Pr, and xylan-Pr: (1): cellulose-Pr, (2): α-1,6-glucan-CH, (3) xylan-Pr. Dielectric constant Dk and dielectric loss tangent Df of cellulose-Pr (circles), α-1,6-glucan-CH (squares), and xylan-Pr (triangles) compared with polyimide, liquid crystal polymer, and fluororesin

In this specification, the terms "contain, include, and have" are concepts that also encompass "consist essentially of" and "consist only of."

In the numerical ranges described in this specification in stages, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of a numerical range of another stage. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. Furthermore, in this specification, a numerical value connected with "~" means a numerical range that includes the numerical values before and after "~" as the upper and lower limits.

The following describes an embodiment of the present invention.

According to a first aspect of the present invention, there is provided a polysaccharide derivative having a structure in which a plurality of monosaccharide units are polymerized, and some or all of the hydrogen atoms of hydroxyl groups of some or all of the monosaccharide units are substituted with -C(O)-( _CH2 ) _m - ^R1 (1) (wherein each ^R1 may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6) or -( _CH2 ) _m - ^R2 (2) (wherein each ^R2 may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6), the polysaccharide derivative being any of the following (i) to (iii):

(i) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group. (ii) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. (iii) A glucan derivative in which the monosaccharide unit is xylose, and each R ^{R 1} may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and is a xylan derivative having no primary hydroxyl group in a side chain. The polysaccharide derivatives (i) to (iii) above have high heat resistance and a low dielectric constant compared to polysaccharide derivatives having an ester chain or ether chain of the same carbon number. The polysaccharide derivatives (ii) and (iii) above have high heat resistance and a low dielectric constant compared to polysaccharide derivatives having an ester chain or ether chain of the same carbon number, and may further have a low dielectric constant.

In one embodiment, the polysaccharide derivative of the first aspect is a polysaccharide derivative of (i), i.e., the polysaccharide derivative is a glucan derivative in which the monosaccharide unit is glucose, each ^R1 , which may be the same or different, is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and each ^R2 , which may be the same or different, is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group. In other words, the polysaccharide derivative has a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ (1) (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or heterocyclic group, and m is 0 to 6) or -(CH ₂ ) _m -R ² (2) (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or heterocyclic group, and m is 0 to 6).

The number of polymerizations of the multiple glucose units of the glucan derivative is not limited, but is, for example, 100 to 20,000. The weight-average molecular weight (Mw) of the glucan derivative is preferably 1.8 × 10 ⁵ or more. Such molecular weight control can be mainly performed by the type of synthetic enzyme, reaction temperature, reaction time, use of surfactant, etc., when synthesizing glucan. In addition, the polydispersity index (PDI; also referred to as molecular weight distribution), which is expressed as the ratio Mw/Mn of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is preferably in the range of 2.0 to 3.0. The weight-average molecular weight (Mw) and the number-average molecular weight (Mn) can be measured using a method known in the art, such as high pressure liquid chromatography (HPLC), size exclusion chromatography (SEC), or gel permeation chromatography (GPC).

In the glucan derivative, hydrogen atoms of hydroxyl groups of some of the glucose units of the glucose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² , or hydrogen atoms of all of the glucose units of the glucose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. In addition, some of the hydrogen atoms of hydroxyl groups of some of the glucose units of the glucose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² , or all of the hydrogen atoms of hydroxyl groups of some of the glucose units of the glucose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² . Some of the hydrogen atoms of the hydroxyl groups of all of the glucose units among the plurality of glucose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² , or all of the hydrogen atoms of the hydroxyl groups of all of the glucose units among the plurality of glucose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² .

When some of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units are substituted with -C(O)-(CH ₂ ) _n -R ¹ or -(CH ₂ ) _n -R ² , the remaining hydrogen atoms may be unsubstituted, may be substituted with a saturated or unsaturated linear hydrocarbon chain, or a saturated or unsaturated branched hydrocarbon chain, or may be substituted with different -C(O)-(CH ₂ ) _n -R ¹ or -(CH ₂ ) _n -R ^2. When the hydrogen atoms of the hydroxyl groups of some or all of the glucose units are substituted with two or more types of substituents, some of the glucose units may be substituted with a certain substituent, and other of the glucose units may be substituted with a different substituent. Alternatively, among the multiple hydroxyl groups in each glucose unit of some or all of the glucose units, one hydroxyl group may be substituted with a certain substituent, and another hydroxyl group may be substituted with a different substituent.

In the glucan derivative, the degree of substitution (DS) with the group of formula (1) or formula (2) is in a preferred embodiment in the range of 2.0 to 3.0, more preferably in the range of 2.5 to 3.0. Here, "degree of substitution" means the average number of hydroxyl groups substituted with esters per glucose unit. That is, a degree of substitution of 3 indicates that all of the hydrogen atoms of the three hydroxyl groups in one glucose unit are groups of formula (1) or formula (2), and that all of the hydrogen atoms of the three hydroxyl groups in each glucose unit are substituted with groups of formula (1) or formula (2). A degree of substitution of 1 indicates that on average one of the hydrogen atoms of the three hydroxyl groups in one glucose unit is substituted with a group of formula (1) or formula (2), and the remaining two hydroxyl groups remain as hydroxyl groups.

In another preferred embodiment, the degree of substitution (DS) with the group of formula (1) or formula (2) is 0.1 to 1.5. In yet another preferred embodiment, the hydrogen atom of one of the three hydroxyl groups of some or all of the glucose units in the plurality of glucose units is substituted with -C(O)-(CH ₂ ) _n -R ¹ (1) or -(CH ₂ ) _n -R ² (2), and the hydrogen atoms of one, two or three hydroxyl groups not substituted with (1) or (2) of some or all of the glucose units in the plurality of glucose units are substituted with a saturated or unsaturated linear hydrocarbon chain or a saturated or unsaturated branched hydrocarbon chain, and the degree of substitution of the hydroxyl groups of the glucose units of the entire glucan derivative of (i) with the group of formula (1) or formula (2) is 0.1 to 1.5.

The hydrogen atom of the hydroxyl group of the glucose unit in one molecule of the glucan derivative may be substituted with one type of -C(O)-(CH ₂ ) _m -R ¹ , or may be substituted with two or more types of -C(O)-(CH ₂ ) _m -R ^1. Furthermore, the hydrogen atom of the hydroxyl group of the glucose unit in one molecule of the glucan derivative may be substituted with one type of -(CH ₂ ) _m -R ² , or may be substituted with two or more types of -(CH ₂ ) _m -R ² .

In the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1), R ¹ is a substituted or unsubstituted cyclic monovalent hydrocarbon group or a substituted or unsubstituted heterocyclic group.

When R ¹ in the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1) is a cyclic hydrocarbon group, the cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Examples of the alicyclic hydrocarbon group include cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 12 members; monocyclic alicyclic hydrocarbon groups, such as cycloalkenyl groups, such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 10 members; and bridged alicyclic hydrocarbon groups (bridged ring hydrocarbon groups) having about 2 to 4 bridged alicyclic rings, such as an adamantane ring, a perhydroindene ring, a decalin ring, a perhydrofluorene ring, a perhydroanthracene ring, a perhydrophenanthrene ring, a tricyclodecane ring, a tricycloundecane ring, a tetracyclododecane ring, a perhydroacenaphthene ring, a perhydrophenalene ring, a norbornane ring, and a norbornene ring.

Aromatic hydrocarbon groups include phenyl and naphthyl groups, preferably having 6 to 20 carbon atoms, and more preferably having 6 to 14 carbon atoms.

When R ¹ in the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1) is a substituted or unsubstituted heterocyclic group, the heterocyclic group may be a saturated or unsaturated heterocyclic group, with an unsaturated heterocyclic group being preferred.

Unsaturated heterocycles include furan, thiophene, pyridine, pyrrole, benzofuran, quinoline, benzothiophene, indole, dibenzofuran, dibenzothiophene, carbazole, and acridine.

In terms of low dielectric constant, the cyclic hydrocarbon group of R ¹ in the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1) is preferably an alicyclic hydrocarbon group.

R ² in —(CH ₂ ) _m —R ² in formula (2) is a substituted or unsubstituted cyclic monovalent hydrocarbon group, or a substituted or unsubstituted monovalent heterocyclic group.

When R ² in —(CH ₂ ) _m —R ² in formula (2) is a cyclic hydrocarbon group, the cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Examples of alicyclic hydrocarbon groups include cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 12 members; monocyclic alicyclic hydrocarbon groups, such as cycloalkenyl groups, such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 10 members; and bridged alicyclic hydrocarbon groups (bridged ring hydrocarbon groups) having about 2 to 4 bridged alicyclic rings, such as an adamantane ring, a perhydroindene ring, a decalin ring, a perhydrofluorene ring, a perhydroanthracene ring, a perhydrophenanthrene ring, a tricyclodecane ring, a tricycloundecane ring, a tetracyclododecane ring, a perhydroacenaphthene ring, a perhydrophenalene ring, a norbornane ring, and a norbornene ring. Examples of aromatic hydrocarbon groups include phenyl and naphthyl groups, preferably aromatic hydrocarbon groups having 6 to 20 carbon atoms, more preferably 6 to 14 carbon atoms.

Aromatic hydrocarbon groups include phenyl and naphthyl groups, preferably having 6 to 20 carbon atoms, and more preferably having 6 to 14 carbon atoms.

When R ² in —(CH ₂ ) _m —R ² of formula (2) is a substituted or unsubstituted heterocyclic group, the heterocyclic group may be a saturated heterocyclic group or an unsaturated heterocyclic group, with an unsaturated heterocyclic group being preferred.

Unsaturated heterocycles include furan, thiophene, pyridine, pyrrole, benzofuran, quinoline, benzothiophene, indole, dibenzofuran, dibenzothiophene, carbazole, and acridine.

When the cyclic hydrocarbon group or heterocycle of ^R1 and ^R2 is substituted, the substituents bonded to the carbon atoms forming the ring are not particularly limited as long as they do not impair the inherent properties of the carbonized glucan derivative, and examples thereof include a hydroxyl group, a mercapto group, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), a maleimide group, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an amino group, an imino group, an aldehyde group, an alkyl group, a vinyl group, an aryl group, a ketone group, a thioketone group, an ester group, a thioester group, an ether group, a thioether group, a phosphoryl group, a phosphono group, and a phosphate group. One to three of the hydrogen atoms bonded to the cyclic hydrocarbon group may be substituted with such a substituent.

In formula (1), m is preferably 0 to 5, more preferably 0 to 3. In one embodiment, in formula (1), m is 0. In another embodiment, in formula (1), m is 1 to 3. In formula (2), m is preferably 0 to 5, more preferably 0 to 3. In one embodiment, in formula (2), m is 0. In another embodiment, in formula (2), m is 1 to 3.

Glycosidic bonds in glucan derivatives include, for example, α-1,3-glycosidic bonds, α-1,4-glycosidic bonds, α-1,6-glycosidic bonds, combinations of α-1,3-glycosidic bonds and α-1,4-glycosidic bonds, combinations of α-1,3-glycosidic bonds and α-1,6-glycosidic bonds, combinations of α-1,4-glycosidic bonds and α-1,6-glycosidic bonds, β-1,3-glycosidic bonds, β-1,4-glycosidic bonds, Examples of such glycosidic bonds include α-1,3-glycosidic bonds, β-1,6-glycosidic bonds, combinations of β-1,3-glycosidic bonds and β-1,4-glycosidic bonds, combinations of β-1,3-glycosidic bonds and β-1,6-glycosidic bonds, and combinations of β-1,4-glycosidic bonds and β-1,6-glycosidic bonds, and preferably include α-1,3-glycosidic bonds, α-1,6-glycosidic bonds, β-1,3-glycosidic bonds, or β-1,4-glycosidic bonds.

In one embodiment, the glucan derivative has a structure in which glucose units are polymerized, the structure being represented by the following formula (3a), (3b), (3c), (3a), or any combination thereof:

　式（３ａ）中、各Ｒは、それぞれ同一でも異なってもよく、－Ｃ（Ｏ）－（ＣＨ_２）_ｍ－Ｒ^１又は－（ＣＨ_２）_ｍ－Ｒ²であり、ｎは１００～２００００である。

In formula (3a), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.

In formula (3b), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.

In formula (3c), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.

In formula (3d), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.

—C(O)—(CH ₂ ) _m —R ¹ and —(CH ₂ ) _m —R ² are as described in relation to formulas (1) and (2).

The glucan derivative preferably has a structure in which glucose units are polymerized in a linear chain, and the glucose units that make up the glucan derivative are not branched.

In one embodiment, the glucan derivative is a derivative of β- ^1,4- glucan (cellulose) in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R 1 or -(CH ₂ ) _m -R ^2. In another embodiment, the glucan derivative is a β-1,4-glucan ester in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ .

In one embodiment, the glucan derivative is a derivative of β-1,3-glucan in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. In another embodiment, the glucan derivative is a β-1,3-glucan ester in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ .

In one embodiment, the glucan derivative is a derivative of α-1,3-glucan in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. In another embodiment, the glucan derivative is an α-1,3-glucan ester in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ .

In one embodiment, the glucan derivative is a derivative of α-1,3-glucan in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. In another embodiment, the glucan derivative is an α-1,6-glucan ester in which some or all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ .

In terms of a high glass transition point, the glucan derivative is preferably an α-1,3-glucan derivative, and in terms of a low dielectric constant, the glucan derivative is preferably a β-1,4-glucan derivative.

The glucan derivative may be in a crystalline form. Heat treatment can crystallize an amorphous glucan derivative or increase the crystallinity of an already crystalline glucan derivative. Crystallization further reduces the dielectric constant of the glucan derivative.

By carrying out heat treatment at a temperature between the glass transition point and the melting point of the glucan derivative, for example at a temperature midway between the glass transition point and the melting point, the crystallization of the glucan derivative proceeds.

In this specification, the method for measuring the glass transition point of the sample follows the measurement method in the Examples.

In this specification, the method for measuring the dielectric constant of the sample follows the measurement method in the Examples, and in the interpretation of the rights of this invention, the measurement frequency is 1 MHz.

The glucan derivative (i) above preferably has a melting point of 250 to 340°C.

The glucan derivative of (i) above preferably has a glass transition point of 120°C or higher and a dielectric constant of 3.0 or lower. A glucan derivative of this configuration has a higher glass transition point than existing thermoplastic resins such as polypropylene, polyethylene terephthalate, and polystyrene, and is preferable in that it has a higher glass transition point and a lower dielectric constant than glucan esters having the same type of glucan chain and linear or branched alkyl acyl groups with the same number of carbon atoms.

The glucan derivative more preferably has a glass transition point of 130°C or higher and a dielectric constant of 3.0 or lower, more preferably has a glass transition point of 150°C or higher and a dielectric constant of 3.0 or lower, more preferably has a glass transition point of 200°C or higher and a dielectric constant of 3.0 or lower, more preferably has a glass transition point of 200°C or higher and a dielectric constant of 2.8 or lower, and more preferably has a glass transition point of 200°C or higher and a dielectric constant of 2.7 or lower.

In one embodiment, the glucan derivative is crystalline, has a glass transition point of 200°C or higher, and a dielectric constant of 2.5 or lower. A glucan derivative having such a configuration is preferable in that it has a high glass transition point and a lower dielectric constant.

The glucan derivative is preferably colorless and transparent. Many highly heat-resistant resins are colored due to the influence of polar groups and contain aromatic rings, so they are almost impermeable to wavelengths of 400 nm or less. However, the glucan derivative of this embodiment is advantageous in that it can be used in a wider range of applications, such as optical elements (optical fibers, optical waveguides).

In one embodiment, the polysaccharide derivative of the first aspect is a polysaccharide derivative of (ii). That is, the polysaccharide derivative is a glucan derivative (ii) in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and does not have a primary hydroxyl group in the side chain.

The number of polymerizations of the glucose units in the glucan derivative, the details of the substituents in the glucan derivative, and the degree of substitution (DS) with the group of formula (1) or formula (2) are as described for the polysaccharide derivative in (i).

In the case of the polysaccharide derivative (ii), since the polysaccharide does not have a primary hydroxyl group in the side chain, it has both high heat resistance and low dielectric constant, and therefore ^R1 and ^R2 in the group of formula (1) or formula (2) may contain a substituted or unsubstituted linear or branched hydrocarbon group in addition to the substituted or unsubstituted cyclic hydrocarbon group or substituted or unsubstituted heterocyclic group in the case of the polysaccharide derivative (i).

When R ¹ is a substituted or unsubstituted linear or branched hydrocarbon group, R ¹ is, for example, a linear or branched alkyl group having 2 to 20 carbon atoms, preferably a linear or branched alkyl or alkenyl group having 3 to 12 carbon atoms, and more preferably a di- or tri-branched alkyl group having 3 to 12 carbon atoms.

When ^R2 is a substituted or unsubstituted linear or branched hydrocarbon group, ^R2 is, for example, a linear or branched alkyl group having 2 to 20 carbon atoms, preferably a linear or branched alkyl group having 3 to 12 carbon atoms, and more preferably a di- or tri-branched alkyl group having 3 to 12 carbon atoms.

By changing the number of branches or the number of carbon atoms of ^R1 or ^R2 , it is possible to change the thermal properties, such as the melting point or glass transition temperature, of the polysaccharide derivative.

The glucan derivative (ii) does not have a primary hydroxyl group in the side chain. To achieve this structure, the glycosidic bonds in the glucan derivative (ii) include α-1,6-glycosidic bonds. Preferably, the glycosidic bonds in the glucan derivative (ii) do not include α-1,3-glycosidic bonds and α-1,4-glycosidic bonds. In one preferred embodiment, 90% or more, 95% or more, 98% or more, or 100% of the total number of glycosidic bonds in the glucan derivative (ii) are α-1,6-glycosidic bonds.

In one embodiment, the glucan derivative has a structure in which glucose units are polymerized, as shown in the following formula (3a):

In formula (3d), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.
In formula (3d), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.

The glucan derivative (ii) above preferably has a melting point of 250 to 340°C.

The glucan derivative of (ii) above preferably has a glass transition point of 120°C or higher and a dielectric constant of 3.0 or lower. Furthermore, the glucan derivative of (ii) above preferably has a dielectric tangent of 0.01 or lower. For example, the dielectric tangent is 0.008 or lower, 0.006 or lower, 0.004 or lower, or 0.003 or lower.

In this specification, the method for measuring the dielectric tangent follows the measurement method in the examples.

In one embodiment, the glucan derivative is crystalline, has a glass transition point of 200°C or higher, and a dielectric constant of 2.5 or lower. A glucan derivative having such a configuration is preferable in that it has a high glass transition point and a lower dielectric constant.

In another embodiment, the glucan derivative is crystalline, has a glass transition point of 200°C or higher, a dielectric constant of 2.5 or lower, and a dielectric dissipation factor of 0.01 or lower. A glucan derivative having such a configuration is preferable in that it has a high glass transition point, a lower dielectric constant, and a low dielectric dissipation factor.

In one embodiment, the polysaccharide derivative of the first aspect is a polysaccharide derivative of (iii), i.e., the polysaccharide derivative is a xylan derivative having no primary hydroxyl group in a side chain, in which the monosaccharide unit is xylose, each ^R1 may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each ^R2 may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group.

The polymerization number of the multiple xylose units of the xylan derivative is not limited, but is, for example, 100 to 20,000. The weight-average molecular weight (Mw) of the xylan derivative is preferably 1.8 × 10 ⁵ or more. Such molecular weight control can be mainly performed by the type of synthetic enzyme, reaction temperature, reaction time, use of surfactant, etc., when synthesizing xylan. In addition, the polydispersity index (PDI; also referred to as molecular weight distribution), which is expressed as the ratio Mw/Mn of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is preferably in the range of 2.0 to 3.0. The weight-average molecular weight (Mw) and the number-average molecular weight (Mn) can be measured using a method known in the art, such as high-pressure liquid chromatography (HPLC), size exclusion chromatography (SEC), or gel permeation chromatography (GPC).

In the xylan derivative, hydrogen atoms of hydroxyl groups of some of the xylose units in the plurality of xylose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² , or hydrogen atoms of all of the xylose units in the plurality of xylose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. Also, some of the hydrogen atoms of hydroxyl groups of some of the xylose units in the plurality of xylose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² , or all of the hydrogen atoms of hydroxyl groups of some of the xylose units in the plurality of xylose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² . Some of the hydrogen atoms of the hydroxyl groups of all of the xylose units in the multiple xylose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² , or all of the hydrogen atoms of the hydroxyl groups of all of the xylose units in the multiple xylose units may be substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² .

When some of the hydrogen atoms of the hydroxyl groups of some or all of the xylose units are substituted with -C(O)-(CH ₂ ) _n -R ¹ or -(CH ₂ ) _n -R ² , the remaining hydrogen atoms may be unsubstituted, or may be substituted with a saturated or unsaturated linear hydrocarbon chain, or a saturated or unsaturated branched hydrocarbon chain, or may be substituted with different -C(O)-(CH ₂ ) _n -R ¹ or -(CH ₂ ) _n -R ^2. When the hydrogen atoms of the hydroxyl groups of some or all of the xylose units are substituted with two or more types of substituents, some of the xylose units may be substituted with a certain substituent, and another of the xylose units may be substituted with a different substituent. Alternatively, among the multiple hydroxyl groups in each xylose unit of some or all of the multiple xylose units, one hydroxyl group may be substituted with a certain substituent, and another hydroxyl group may be substituted with a different substituent.

In the above xylan derivatives, the degree of substitution (DS) with the group of formula (1) or formula (2) is in a preferred embodiment in the range of 1.0 to 2.0, more preferably in the range of 1.5 to 2.0. Here, "degree of substitution" means the average number of hydroxyl groups substituted with esters per xylose unit. That is, a degree of substitution of 2 indicates that both hydrogen atoms of the two hydroxyl groups in one xylose unit are groups of formula (1) or formula (2), and that the hydrogen atoms of the two hydroxyl groups in each xylose unit are all substituted with groups of formula (1) or formula (2). A degree of substitution of 1 indicates that on average one of the hydrogen atoms of the two hydroxyl groups in one xylose unit is substituted with a group of formula (1) or formula (2), and the remaining hydroxyl group remains a hydroxyl group.

In another preferred embodiment, the degree of substitution (DS) with the group of formula (1) or formula (2) is 0.1 to 1.5. In yet another preferred embodiment, the hydrogen atom of one of the two hydroxyl groups of a part or all of the xylose units is substituted with -C(O)-(CH ₂ ) _n -R ¹ (1) or -(CH ₂ ) _n -R ² (2), and the hydrogen atoms of one or two hydroxyl groups not substituted with (1) or (2) of a part or all of the xylose units are substituted with a saturated or unsaturated linear hydrocarbon chain or a saturated or unsaturated branched hydrocarbon chain, and the degree of substitution of the hydroxyl groups of the xylose units of the entire xylan derivative (ii) with the group of formula (1) or (2) is 0.1 to 1.5.

The hydrogen atom of the hydroxyl group of the xylose unit in one molecule of the xylan derivative may be substituted with one type of -C(O)-(CH ₂ ) _m -R ¹ or may be substituted with two types of -C(O)-(CH ₂ ) _m -R ^1. Furthermore, the hydrogen atom of the hydroxyl group of the xylose unit in one molecule of the xylan derivative may be substituted with one type of -(CH ₂ ) _m -R ² or may be substituted with two or more types of -(CH ₂ ) _m -R ² .

In the case of the polysaccharide derivative (iii), since the polysaccharide does not have a primary hydroxyl group in the side chain, it has both high heat resistance and low dielectric constant, and therefore ^R1 and ^R2 in the group of formula (1) or formula (2) may contain a substituted or unsubstituted branched chain hydrocarbon group in addition to the substituted or unsubstituted cyclic hydrocarbon group or substituted or unsubstituted heterocyclic group in the case of the polysaccharide derivative (i).

In the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1), R ¹ is a substituted or unsubstituted branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group.

When R ¹ in the acyl group -C(O)-(CH ₂ ) _m -R ¹ of formula (1) is a substituted or unsubstituted branched hydrocarbon group, R ¹ is, for example, a branched alkyl group having 2 to 20 carbon atoms, preferably a branched alkyl or alkenyl group having 3 to 12 carbon atoms, and more preferably a di- or tri-branched alkyl or alkenyl group having 3 to 12 carbon atoms.

When R ¹ in the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1) is a cyclic hydrocarbon group, the cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Examples of the alicyclic hydrocarbon group include cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 12 members; monocyclic alicyclic hydrocarbon groups, such as cycloalkenyl groups, such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 10 members; and bridged alicyclic hydrocarbon groups (bridged ring hydrocarbon groups) having about 2 to 4 bridged alicyclic rings, such as an adamantane ring, a perhydroindene ring, a decalin ring, a perhydrofluorene ring, a perhydroanthracene ring, a perhydrophenanthrene ring, a tricyclodecane ring, a tricycloundecane ring, a tetracyclododecane ring, a perhydroacenaphthene ring, a perhydrophenalene ring, a norbornane ring, and a norbornene ring.

Aromatic hydrocarbon groups include phenyl and naphthyl groups, preferably having 6 to 20 carbon atoms, and more preferably having 6 to 14 carbon atoms.

When R ¹ in the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1) is a substituted or unsubstituted heterocyclic group, the heterocyclic group may be a saturated or unsaturated heterocyclic group, with an unsaturated heterocyclic group being preferred.

Unsaturated heterocycles include furan, thiophene, pyridine, pyrrole, benzofuran, quinoline, benzothiophene, indole, dibenzofuran, dibenzothiophene, carbazole, and acridine.

In terms of low dielectric constant, the cyclic hydrocarbon group of R ¹ in the acyl group --C(O)--(CH ₂ ) _m --R ¹ of formula (1) is preferably an alicyclic hydrocarbon group.

R ² in --(CH ₂ ) _m --R ² in formula (2) is a substituted or unsubstituted branched hydrocarbon group, a substituted or unsubstituted cyclic monovalent hydrocarbon group, or a substituted or unsubstituted monovalent heterocyclic group.

When R ² in -(CH ₂ ) _m -R ² in formula (2) is a substituted or unsubstituted branched hydrocarbon group, R ² is, for example, a branched alkyl group having 2 to 20 carbon atoms, preferably a branched alkyl group having 3 to 12 carbon atoms, and more preferably a di- or tri-branched alkyl group having 3 to 12 carbon atoms.

When R ² in —(CH ₂ ) _m —R ² in formula (2) is a cyclic hydrocarbon group, the cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Examples of alicyclic hydrocarbon groups include cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 12 members; monocyclic alicyclic hydrocarbon groups, such as cycloalkenyl groups, such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl groups, preferably having 3 to 20 members, more preferably having 3 to 15 members, and even more preferably having 3 to 10 members; and bridged alicyclic hydrocarbon groups (bridged ring hydrocarbon groups) having about 2 to 4 bridged alicyclic rings, such as an adamantane ring, a perhydroindene ring, a decalin ring, a perhydrofluorene ring, a perhydroanthracene ring, a perhydrophenanthrene ring, a tricyclodecane ring, a tricycloundecane ring, a tetracyclododecane ring, a perhydroacenaphthene ring, a perhydrophenalene ring, a norbornane ring, and a norbornene ring. Examples of aromatic hydrocarbon groups include phenyl and naphthyl groups, preferably aromatic hydrocarbon groups having 6 to 20 carbon atoms, more preferably 6 to 14 carbon atoms.

Aromatic hydrocarbon groups include phenyl and naphthyl groups, preferably having 6 to 20 carbon atoms, and more preferably having 6 to 14 carbon atoms.

When R ² in —(CH ₂ ) _m —R ² of formula (2) is a substituted or unsubstituted heterocyclic group, the heterocyclic group may be a saturated heterocyclic group or an unsaturated heterocyclic group, with an unsaturated heterocyclic group being preferred.

Unsaturated heterocycles include furan, thiophene, pyridine, pyrrole, benzofuran, quinoline, benzothiophene, indole, dibenzofuran, dibenzothiophene, carbazole, and acridine.

When the cyclic hydrocarbon group or heterocycle of ^R1 and ^R2 is substituted, the substituents bonded to the carbon atoms forming the ring are not particularly limited as long as they do not impair the inherent properties of the xylan derivative, and examples thereof include a hydroxyl group, a mercapto group, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), a maleimide group, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an amino group, an imino group, an aldehyde group, an alkyl group, a vinyl group, an aryl group, a ketone group, a thioketone group, an ester group, a thioester group, an ether group, a thioether group, a phosphoryl group, a phosphono group, and a phosphate group. One to three of the hydrogen atoms bonded to the cyclic hydrocarbon group may be substituted with such a substituent.

In formula (1), m is preferably 0 to 5, more preferably 0 to 3. In one embodiment, in formula (1), m is 0. In another embodiment, in formula (1), m is 1 to 3. In formula (2), m is preferably 0 to 5, more preferably 0 to 3. In one embodiment, in formula (2), m is 0. In another embodiment, in formula (2), m is 1 to 3.

By changing the number of branches or the number of carbon atoms of ^R1 or ^R2 , it is possible to change the thermal properties, such as the melting point or glass transition temperature, of the polysaccharide derivative.

The xylan derivative (iii) contains, for example, β-1,3-bonds, β-1,4-bonds, or a combination of β-1,3-bonds and β-1,4-bonds.

In one embodiment, the xylan derivative has a structure in which xylose units are polymerized, the structure being represented by the following formula (3e), (3f), or a combination thereof:

　式（３ｅ）中、各Ｒは、それぞれ同一でも異なってもよく、－Ｃ（Ｏ）－（ＣＨ_２）_ｍ－Ｒ^１又は－（ＣＨ_２）_ｍ－Ｒ²であり、ｎは１００～２００００である。

In formula (3e), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.

In formula (3f), each R may be the same or different and is —C(O)—(CH ₂ ) _m —R ¹ or —(CH ₂ ) _m —R ² , and n is 100 to 20,000.

—C(O)—(CH ₂ ) _m —R ¹ and —(CH ₂ ) _m —R ² are as described in relation to formulas (1) and (2).

The xylan derivative preferably has a structure in which xylose units are polymerized in a linear chain, and the xylose units that make up the xylan derivative are not branched.

In one embodiment, the xylan derivative is a derivative of β- ^1,4-xylan (xylose) in which some or all of the hydrogen atoms in the hydroxyl groups of the xylose units are substituted with -C(O)-(CH ₂ ) _m -R 1 or -(CH ₂ ) _m -R ^2. In another embodiment, the xylan derivative is a β-1,4-xylan ester in which some or all of the hydrogen atoms in the hydroxyl groups of the xylose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ .

In one embodiment, the xylan derivative is a derivative of β-1,3-xylan in which some or all of the hydrogen atoms in the hydroxyl groups of the xylose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. In another embodiment, the xylan derivative is a β-1,3-xylan ester in which some or all of the hydrogen atoms in the hydroxyl groups of the xylose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ .

In terms of low dielectric constant, the xylan derivative is preferably a derivative of β-1,4-xylan.

The xylan derivative may be in a crystalline form. Heat treatment can crystallize an amorphous xylan derivative or increase the crystallinity of an already crystalline xylan derivative. Crystallization further reduces the dielectric constant of the xylan derivative.

The xylan derivative (iii) above preferably has a melting point of 250 to 340°C.

The xylan derivative (iii) above preferably has a glass transition point of 120°C or higher and a dielectric constant of 3.0 or lower. Furthermore, the xylan derivative (iii) above preferably has a dielectric tangent of 0.01 or lower. For example, the dielectric tangent is 0.008 or lower, 0.006 or lower, 0.004 or lower, or 0.003 or lower.

In this specification, the method for measuring the dielectric tangent follows the measurement method in the examples.

In one embodiment, the xylan derivative is crystalline, has a glass transition point of 200°C or higher, and a dielectric constant of 2.5 or lower. Xylan derivatives having such a configuration are preferred in that they have a high glass transition point and a lower dielectric constant.

In another embodiment, the xylan derivative is crystalline, has a glass transition point of 200°C or higher, a dielectric constant of 2.5 or lower, and a dielectric dissipation factor of 0.01 or lower. Xylan derivatives of this configuration are preferred in that they have a high glass transition point, a lower dielectric constant, and a low dielectric dissipation factor.

Here, we will explain the method for producing the polysaccharide derivatives. Polysaccharides such as glucan and xylan can be synthesized by various known production methods, or commercially available products can be used.

Substitution of some or all of the hydrogen atoms of the hydroxyl groups of some or all of the monosaccharide units constituting a polysaccharide (the multiple glucose units of a glucan, or the multiple xylose units of a xylan) with -C(O)-(CH ₂ ) _m -R ¹ groups can be achieved, for example, by reacting the hydroxyl groups of the monosaccharide units with a carboxylic acid to esterify the hydroxyl groups. Various methods are known for esterifying hydroxyl groups.

The substitution of some or all of the hydrogen atoms of the hydroxyl groups of some or all of the monosaccharide units constituting a polysaccharide with -(CH ₂ ) _m -R ² groups can be achieved by reacting the hydroxyl groups of the monosaccharide units with an alkylating agent such as iodomethane in the presence of a base. For example, in the case of the synthesis of methyl(alkyl)cellulose, 1.0 g of cellulose was swollen in 50 ml of 37 wt% NaOH. Methyl(alkyl) halide was added and the mixture was stirred at 80°C for 24 hours. The reaction product was neutralized with acetic acid, dialyzed against water, and dried to obtain methyl(alkyl)cellulose. N. I. Nikitim, The Chemistry of Cellulose and Wood. Oldbourne Press, 1966, p. 307 Various methods are known for substituting hydroxy with alkoxy.

In this way, monosaccharide derivatives such as glucan derivatives and xylan derivatives can be produced.

According to a second aspect of the present invention, there is provided a grafted glucan derivative in which a second glucan derivative different from the first glucan derivative is grafted to a first glucan derivative, each of the first glucan derivative and the second glucan derivative has a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units of the first glucan derivative and the second glucan derivative are substituted with -C(O)-(CH ₂ ) _n -R ¹ (1) (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, n is 0 to 6) or -(CH ₂ ) _n -R ² (2) (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, n is 0 to 6).

Examples of the first glucan derivative include derivatives of α-1,6-glucan, α-1,4-glucan, α-1,3-glucan, etc., in which some or all of the hydrogen atoms in the hydroxyl groups bonded to carbons other than the 6-position carbon of the glucose unit of the first glucan derivative are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. -C(O)-(CH ₂ ) _m -R ¹ and -(CH ₂ ) _m -R ² are as explained in relation to formulas (1) and (2) of the first aspect above.

In one embodiment, the first glucan derivative is a derivative of α-1,6-glucan.

The second glucan derivative is, for example, a derivative of α-1,6-glucan, α-1,4-glucan, α-1,3-glucan, etc., and includes the glucan derivatives described in the first aspect above.

In one embodiment, the second glucan derivative is a derivative of α-1,3-glucan in which some of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. In another embodiment, the second glucan derivative is a derivative of α-1,3-glucan in which all of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. In another embodiment, the second glucan derivative is an α-1,3-glucan ester in which some of the hydrogen atoms in the hydroxyl groups of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ . In another embodiment, the second glucan derivative is an α-1,3-glucan ester in which all of the hydrogen atoms in the hydroxyl groups of the glucose units are replaced with —C(O)—(CH ₂ ) _m —R ¹ .

Alternatively, each of the first glucan derivative and the second glucan derivative may be, for example, a derivative of β-1,6-glucan, β-1,4-glucan, β-1,3-glucan or the like, in which some or all of the hydrogen atoms in the hydroxyl groups bonded to carbons other than the 6-position carbon of the glucose unit of the first glucan derivative are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ^2. -C(O)-(CH ₂ ) _m -R ¹ and -(CH ₂ ) _m -R ² are as explained in relation to formulas (1) and (2) of the first aspect above.

Alternatively, one of the first glucan derivative and the second glucan derivative may be, for example, an α-1,6-glucan, an α-1,4-glucan, an α-1,3-glucan, or the like, in which some or all of the hydrogen atoms in the hydroxyl groups bonded to a carbon other than the 6-position carbon of the glucose unit of the first glucan derivative are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² , and the other of the first glucan derivative and the second glucan derivative may be, for example, a β-1,6-glucan, a β-1,4-glucan, a β-1,3-glucan, or the like, in which some or all of the hydrogen atoms in the hydroxyl groups bonded to a carbon other than the 6-position carbon of the glucose unit of the first glucan derivative are substituted with -C(O)-(CH ₂ ) _m -R ¹ or -(CH ₂ ) _m -R ² . —C(O)—(CH ₂ ) _m —R ¹ and —(CH ₂ ) _m —R ² are as explained in relation to formulae (1) and (2) in the first embodiment above.

The glucan derivative preferably has a glass transition point of 120°C or higher and a dielectric constant of 3.0 or less.

The glucan derivative more preferably has a glass transition point of 130°C or higher and a dielectric constant of 3.0 or lower, more preferably has a glass transition point of 150°C or higher and a dielectric constant of 3.0 or lower, more preferably has a glass transition point of 200°C or higher and a dielectric constant of 3.0 or lower, more preferably has a glass transition point of 200°C or higher and a dielectric constant of 2.8 or lower, and more preferably has a glass transition point of 200°C or higher and a dielectric constant of 2.7 or lower.

In one embodiment, the grafted glucan derivative is crystalline, has a glass transition point of 200°C or higher, and a dielectric constant of 2.5 or lower. A glucan derivative having such a configuration is preferable in that it has a high glass transition point and a lower dielectric constant.

The grafted glucan derivative is preferably colorless and transparent.

Next, we will explain the method for producing the above grafted glucan derivative.

Grafted glucan can be produced by various known methods. For example, grafted glucan obtained by grafting α-1,3-glucan to α-1,6-glucan (dextran) can be obtained by adding and elongating an α-1,3-glucan side chain from the C3 position of the raw material α-1,6-glucan (see, for example, JP 2018-198570 A). The reaction is carried out by an enzymatic reaction of sucrose with glucosyltransferase using water as a solvent. Various methods are known for grafting glucan side chains to such glucans. In the obtained grafted glucan, some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units of the multiple glucose units can be replaced with -C(O)-(CH ₂ ) _m -R ¹ groups or -(CH ₂ ) _m -R ² groups by the method described above for the production method of the glucan derivative.

According to a third aspect of the present invention, there is provided a resin composition containing one or more of the polysaccharide derivatives of the first aspect and/or the grafted glucan derivatives of the second aspect.

The content of the polysaccharide derivative (including the polysaccharide derivative of the first embodiment and the glucan derivative of the second embodiment) in the resin composition is not particularly limited, but the polysaccharide derivative is preferably contained in the resin composition in an amount of 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, and more preferably 80 to 100% by mass.

The resin composition may further contain one or more additives, such as fillers, abrasion resistance improvers, flame retardants, tracking resistance improvers, acid resistance improvers, thermal conductivity improvers, defoamers, leveling agents, surface tension adjusters, and colorants.

According to a fourth aspect of the present invention, there is provided a molded article obtained by molding any of the polysaccharide derivatives of the above aspects or the resin composition of the above aspects.

Such molded bodies can be molded using methods known in the art, such as injection molding, compression molding, blow molding, inflation molding, Engel molding, extrusion molding, extrusion lamination molding, rotational molding, calendar molding, vacuum molding, stamping molding, spray-up molding, lamination molding, casting, injection molding, hand-laid molding, low-pressure molding, transfer molding, foam molding, blow molding, or the T-die method.

Preferably, the molded article is a film. A method for producing a film from the polysaccharide derivative or resin composition can be a method known in the art. For example, a film of a desired thickness can be obtained by applying a solution in which the ester derivative is dissolved in a suitable organic solvent and removing the solvent. As the organic solvent, for example, methylene chloride (dichloromethane), methanol, chloroform, tetrachloroethane, formic acid, acetic acid, bromoform, pyridine, dioxane, ethanol, acetone, alcohols, aromatic compounds such as toluene, esters such as ethyl acetate and propyl acetate, ethers such as tetrahydrofuran, methyl cellosolve, and ethylene glycol monomethyl ether, or combinations thereof can be used. In addition, a film can be formed using a method such as spin coating or spraying. Such a film can also be applied to the surface of a material by a hot melt method to bond the materials together.

The molded article preferably has excellent transparency and can be used as an optical film. For example, a film having a thickness of about 0.05 to 0.2 mm can have a maximum transmittance of 60% or more. In particular, the film has transparency even in the ultraviolet region, and preferably has a transmittance of 40% or more at 300 nm.

The uses of the molded article of the embodiment of the present invention are not particularly limited, but examples include components for automobiles, home appliances, electrical or electronic devices (including office automation or media-related devices, optical devices, and communication devices), machine parts, housing or building materials, etc. Among the above, the molded article of the embodiment of the present invention has high heat resistance, low dielectric constant, and transparency, and is therefore particularly suitable for use in circuit boards (circuit board materials including circuit protection materials) used in electronic devices, and optical films, optical fibers, and optical waveguides used in image display devices.

According to a fifth aspect of the present invention, there is provided a circuit board material comprising any of the polysaccharide derivatives of the above aspects or the resin composition of the above aspects.

The polysaccharide derivative and resin composition of the present invention according to the above embodiment have high heat resistance, low dielectric constant, and transparency, and therefore can be suitably used for the same applications as those described for the molded article.

The present invention also includes the following embodiments:

Item 1.
A polysaccharide derivative having a structure in which a plurality of monosaccharide units are polymerized, in which some or all of the hydrogen atoms of the hydroxyl groups of some or all of the monosaccharide units in the plurality of monosaccharide units are substituted with -C(O)-(CH ₂ ) _m -R ¹ (wherein each R ¹ may be the same or different and is a substituted or unsubstituted straight-chain or branched-chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6) or -(CH ₂ ) _m -R ² (wherein each R ² may be the same or different and is a substituted or unsubstituted straight-chain or branched-chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6), which is any of the following (i) to (iii):

(i) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group. (ii) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. (iii) A glucan derivative in which the monosaccharide unit is xylose, and each R Item 2. A xylan derivative having no primary hydroxyl group in a side chain, wherein R ¹ may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group.
Item 2. A polysaccharide derivative according to Item 1, which is a glucan derivative having a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and in which some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R ¹ (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6) or -(CH ₂ ) _m -R ² (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6). The feature of the invention in Item 2. may be used interchangeably with the feature of the invention in (i) of Item 1.

Item 3.
Item 3. The polysaccharide derivative according to Item 1 or 2, wherein the glycosidic bond comprises an α-1,3-glycosidic bond, an α-1,6-glycosidic bond, a β-1,3-glycosidic bond, or a β-1,4-glycosidic bond.

Item 4.
Item 4. The polysaccharide derivative according to any one of Items 1 to 3, wherein the cyclic hydrocarbon group of R ¹ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Item 5.
Item 5. The polysaccharide derivative according to any one of Items 1 to 4, wherein the alicyclic hydrocarbon group is a monocyclic alicyclic hydrocarbon group having a 3- to 12-membered ring.

Item 6.
Item 2. A polysaccharide derivative according to Item 1, which is a glucan derivative having no primary hydroxyl group in a side chain, wherein the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group.

Item 7.
Item 7. The polysaccharide derivative according to Item 6, wherein the glycosidic bond comprises an α-1,6-glycosidic bond.

Item 8.
Item 8. The polysaccharide derivative according to Item 6 or 7, wherein the cyclic hydrocarbon group of R ¹ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Item 9.
Item 9. The polysaccharide derivative according to any one of Items 6 to 8, wherein the alicyclic hydrocarbon group is a monocyclic alicyclic hydrocarbon having a 3- to 12-membered ring.

Item 10.
Item 8. The polysaccharide derivative according to Item 6 or 7, wherein each R ¹ may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, and each R ² may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group.

Item 11.
Item 10. The polysaccharide derivative according to any one of Items 6 to 9, wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group.

Item 12.
Item 2. A polysaccharide derivative according to Item 1, which is a xylan derivative having no primary hydroxyl group in a side chain, wherein the monosaccharide unit is xylose, each R ¹ may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group.

Item 13.
Item 13. The polysaccharide derivative according to item 12, which contains a β1,3-bond, a β1,4-bond, or both.
Item 14. The polysaccharide derivative according to item 12 or 13, wherein the cyclic hydrocarbon group of R ¹ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group.

Item 15.
Item 15. The polysaccharide derivative according to any one of Items 12 to 14, wherein the alicyclic hydrocarbon group is a monocyclic alicyclic hydrocarbon group having a 3- to 12-membered ring.

Item 15.
Item 16. The polysaccharide derivative according to any one of Items 12 to 15, wherein each R ¹ may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, and each R ² may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group.

Item 16.
Item 16. The polysaccharide derivative according to any one of Items 12 to 15, wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group.

Item 17.
Item 17. The polysaccharide derivative according to any one of Items 1 to 16, which is a crystal.

Item 18.
Item 18. The polysaccharide derivative according to any one of Items 1 to 17, having a glass transition point of 200° C. or higher and a dielectric constant of 3.0 or lower.

Item 19.
Item 19. The polysaccharide derivative according to any one of Items 1 to 18, having a dielectric tangent of 0.01 or less, 0.008 or less, 0.006 or less, 0.004 or less, or 0.003 or less.

Item 20.
A grafted glucan derivative in which a second glucan derivative different from the first glucan derivative is grafted to a first glucan derivative, each of the first glucan derivative and the second glucan derivative has a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units of the first glucan derivative and the second glucan derivative are substituted with -C(O)-(CH ₂ ) _m -R ¹ (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6) or -(CH ₂ ) _m -R ² (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6).

Item 21.
Item 21. A glucan derivative according to item 20, having a glass transition point of 200° C. or higher and a dielectric constant of 3.0 or lower.

Item 22.
Item 22. The polysaccharide derivative according to item 20 or 21, having a dielectric tangent of 0.01 or less.

Item 23.
A resin composition comprising one or more of the polysaccharide derivatives according to any one of items 1 to 19 or the glucan derivatives according to any one of items 20 to 22.

Item 24.
Item 24. A molded article obtained by molding the polysaccharide derivative according to any one of items 1 to 19, the glucan derivative according to any one of items 20 to 22, or the resin composition according to item 23.

Item 25.
Item 25. The molded article according to item 24, which is a film.

Item 26.
Item 24. A circuit board material comprising the glucan derivative according to any one of items 1 to 19, the glucan derivative according to any one of items 20 to 22, or the resin composition according to item 23.

The disclosures of all patent applications and publications cited herein are hereby incorporated by reference in their entirety.

The following examples are intended for illustrative purposes only and are not intended to limit the scope of the invention.

Test Example 1
1. Sample Production Commercially available ashless pulp was used for β-1,4-glucan. Paramylon extracted from Euglena was used for β-1,3-glucan. α-1,3-glucan was biosynthesized from a sucrose solution using recombinant glucosyltransferase produced in E. coli according to the disclosure of JP 2018-102249 A. Commercially available dextran was used for α-1,6-glucan. Grafted glucan was biosynthesized from a sucrose solution in the presence of dextran using recombinant glucosyltransferase produced in E. coli according to the method described in JP 2018-198570 A.

Esterification of each glucan was carried out using carboxylic acid and trifluoroacetic acid (TFAA). 9 ml of any carboxylic acid and 12 ml of trifluoroacetic anhydride were placed in a recovery flask and stirred in an oil bath at 50°C for 5 minutes. 0.5 g of dried polysaccharide was added to the resulting mixed solution and stirred at 50°C for 1 hour. After the reaction, a brown, transparent, homogeneous solution was obtained. This reaction solution was poured into 500 ml of a mixed solvent of methanol and water to precipitate the target product, which was then recovered by filtration. The recovered white precipitate was dissolved in 50 ml of chloroform and washed. The chloroform solution was reprecipitated in a mixed solvent of methanol and water and recovered by filtration. The product was dried at room temperature and pressure for 2 days, and finally dried in vacuum for 6 hours.

The cast film was produced by the solvent casting method. 0.50 g of glucan ester derivative was dissolved in 10 ml of chloroform and poured into a Teflon (registered trademark) petri dish with a diameter of 5.4 cm. After leaving it at room temperature and normal pressure for 3 days, it was vacuum dried for 6 hours to obtain a cast film.

2. Measurement of various physical properties
(1) Measurement of glass transition point The glass transition point of each sample was measured by the following measurement method. A dynamic viscoelasticity measuring device DMA 8000 (PerkinElmer Co., Ltd.) was used. The powder sample was sandwiched between aluminum pans (material pockets) to prepare the measurement sample. The measurement conditions were as follows: under a nitrogen atmosphere, shear mode, temperature range 50°C-380°C, heating rate 4°C/min, and measurement frequency 10 Hz.

The glass transition temperatures of general-purpose plastics are those listed in J.E. Mark, Polymer Data Handbook (second ed.), Oxford University Press, New York (2009).

(2) Method for Measuring Dielectric Constant The dielectric constant of the samples was measured by the following method. An E4991B impedance analyzer (Keysight) was used. The test pieces were cast films measuring 2 cm square with thicknesses of 300 μm to 500 μm. The test temperature was 23° C., and the measurement frequency was 1 MHz to 1 GHz. The dielectric constant of the same sample did not change significantly within the measurement frequency range (1 MHz to 1 GHz band).

The dielectric constants (measured at 1 MHz) of common plastics (polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS)) are taken from J.E. Mark, Polymer Data Handbook (second ed.), Oxford University Press, New York (2009).

Mw and PDI were measured by GPC. K-802 and K-806M (Showa Denko) columns and RID-16A (Shimadzu) detector were used. HPLC chloroform was used as the solvent, with a flow rate of 0.8 ml/min, column temperature of 40°C, injection volume of 50 μl, and sample concentration of 1 mg/ml. A calibration curve was created using polyethylene standard (Showa Denko) as the reference substance.

A DSC8500 (Perkin Elmer) was used to measure Tm. Cast films were used as samples, weighing approximately 2 mg. The melting point of each sample was evaluated during the heating process from -30°C to 380°C (1st run). The heating rate was 20°C/min.

3. Results Tables 1-4 show the number of carbon atoms in the side chain, weight average molecular weight (Mw), polydispersity index (PDI, weight average molecular weight Mw/number average molecular weight Mn), glass transition point (Tg), and melting point (Tm) of each sample. In the tables, the samples are named according to the following rule: (name of main chain glucan)-(carboxylic acid used for esterification with hydroxyl groups of glucose units). For example, β-1,4-glucan-Ac indicates that the main chain glucan is β-1,4-glucan and the hydroxyl groups of the glucose units are acetate esters. "-" in Tables 1-4 indicates that measurement was not performed or that measurement was not possible.

In Table 1-4, Pr is propionic acid, Bu is butanoic acid, Va is valeric acid, Hex is hexanoic acid, 2MPr is 2-methylpropionic acid, 2MBu is 2-methylbutanoic acid, 2MVa is 2-methylvaleric acid, 2MHex is 2-methylhexanoic acid, 22DMPr is 2,2-dimethylpropionic acid, CB is cyclobutanecarboxylic acid, CP is cyclopentanecarboxylic acid, CH is cyclohexanecarboxylic acid, AD is adamantanecarboxylic acid, and BZ is benzoic acid.

As shown in Figures 1 (A)-(C), for all glucan ester derivatives, the glass transition temperature decreased for both linear and branched chains as the number of carbon atoms in the side chain increased. However, for cyclic glucan ester derivatives, the glass transition temperature did not decrease even when the number of carbon atoms in the side chain increased. As a result, when the number of carbon atoms in the side chain was the same, the glass transition temperature of the cyclic glucan ester derivatives was often higher than that of the linear and branched chains. In particular, the glass transition temperature of α-1,3-glucan-CH was 205°C. This value is higher than that of any polysaccharide ester derivative with side chains of other shapes. Furthermore, its dielectric constant was 2.65, which is the lowest level compared to other polysaccharide ester derivatives.

For all glucan ester derivatives, in the case of derivatives with linear and branched side chains, the dielectric constant and glass transition point decreased as the number of carbon atoms in the side chain increased. In other words, there was a trade-off between a low dielectric constant and a high glass transition point. However, in the case of derivatives with cyclic side chains, only the dielectric constant decreased as the number of carbon atoms increased. Furthermore, the glass transition point of derivatives with cyclic side chains was higher than that of derivatives with linear or branched side chains with the same number of carbon atoms. Thus, the derivatives with cyclic side chains were thermoplastic resins that achieved the desired levels of dielectric constant and glass transition point.

This can be explained as follows. First, regardless of the shape of the side chain, as the number of carbon atoms in the side chain increases, the polarity within the molecule decreases. Therefore, it is thought that the dielectric constant decreases as the number of carbon atoms in the side chain increases, regardless of the shape of the side chain.

Secondly, in the case of linear or branched side chains, the mobility of the side chain increases as the number of carbon atoms increases, improving its function as an internal plasticizer. As a result, the glass transition point decreases. On the other hand, in the case of cyclic structures, as the number of carbon atoms increases, the ring becomes larger and the bulkiness increases. In other words, in the case of cyclic structures, it is thought that the function as an internal plasticizer does not improve even if the number of carbon atoms increases. As a result, it is thought that derivatives with cyclic side chains have higher molecular chain rigidity and show higher glass transition points than derivatives with linear or branched side chains.

As shown in Figures 2(A)-(C), when a cast film of a glucan ester derivative was heat-treated at a temperature between the glass transition point and the melting point, the dielectric constant decreased. This is thought to be because the molecular chains crystallized, restricting their mobility, making it difficult to induce orientation polarization, which contributes to an increase in the dielectric constant.

試験例２
１．サンプルの製造
　α－１，３－グルカンーＣＨ及びα－１，６－グルカン－ＣＨを、試験例１に記載した通りに製造した。グルカンのエステル化は、カルボン酸無水物とジメチルアセトアミド(DMAc)とリチウムクロライド(LiCl)を用いて行った。8 gのLiClを溶解させた100 mlのDMAcに、0.5 gの乾燥した多糖を加え、7０℃のオイルバス中で、3時間攪拌した。20 ｍｌの任意のカルボン酸無水物を加え、7０℃のオイルバス中で、24時間攪拌した。反応後、茶色く透明な均一溶液になった。この反応液を５００ｍlのメタノールと水の混合溶媒に注ぎ、目的物を沈殿させ、ろ過によって回収した。回収した白色沈殿を５０ｍｌのクロロホルムに溶かし洗浄を行った。そのクロロホルム溶液をメタノールと水の混合溶媒に再沈殿させ、ろ過によって回収した。２日間常温常圧で乾燥し、最後に６時間真空乾燥した。

Test Example 2
1. Preparation of Samples α-1,3-glucan-CH and α-1,6-glucan-CH were prepared as described in Test Example 1. Glucan esterification was performed using carboxylic anhydride, dimethylacetamide (DMAc), and lithium chloride (LiCl). 0.5 g of dried polysaccharide was added to 100 ml of DMAc in which 8 g of LiCl was dissolved, and the mixture was stirred in an oil bath at 70°C for 3 hours. 20 ml of any carboxylic anhydride was added, and the mixture was stirred in an oil bath at 70°C for 24 hours. After the reaction, a brown, transparent, homogeneous solution was obtained. The reaction solution was poured into a mixed solvent of 500 ml of methanol and water, and the target product was precipitated and collected by filtration. The collected white precipitate was dissolved in 50 ml of chloroform and washed. The chloroform solution was reprecipitated in a mixed solvent of methanol and water, and collected by filtration. The mixture was dried at room temperature and pressure for 2 days, and finally dried in vacuum for 6 hours.

2. Measurement of various physical properties
(1) Measurement of Glass Transition Point The glass transition point of a cast film sample of α-1,6-glucan-CH was measured in the same manner as in Test Example 1.

(2) Measurement of Dielectric Constant The dielectric constant of the sample was measured in the same manner as in Test Example 1. The thickness of the cast film was 300 μm.

(3) Measurement of Dielectric Tangent The dielectric tangent of the sample was measured by the following measurement method. An E4991B impedance analyzer (Keysight) was used. The test piece was a cast film of 2 cm square with a thickness of 300 μm to 500 μm. The test temperature was 23° C., and the measurement frequency was 1 MHz to 1 GHz.

3. Results α-1,6-glucan-CH is a compound synthesized by esterifying the hydroxyl groups of α-1,6-glucan with cyclohexane carboxylic acid (Figure 3 (A)). ^{The 1} H NMR spectrum of the synthesized α-1,6-glucan-CH is shown in Figure 3 (B). α-1,6-glucan-CH is crystalline, and the melting point (Tm) and glass transition point (Tg) of α-1,6-glucan-CH measured by the same method as in Test Example 1 were 255°C and 142°C, respectively (data omitted).

As shown in Figure 4, the dielectric constant of α-1,6-glucan-CH is lower than that of α-1,3-glucan-CH, and the dielectric tangent of α-1,6-glucan-CH is also lower than that of α-1,3-glucan-CH. In particular, the dielectric tangent of α-1,6-glucan-CH is more than 70% lower than that of α-1,3-glucan-CH. This is thought to be because α-1,6-glucan-CH does not have a highly mobile primary hydroxyl group in its side chain, suppressing the orientation of the dipole.

As shown in Figure 5, α-1,6-glucan-CH has a lower dielectric constant than typical polyimides and liquid crystal polymers, and a dielectric dissipation factor comparable to that of liquid crystal polymers. For the dielectric constant and dielectric dissipation factor of polyimides and liquid crystal polymers, see https://xtech.nikkei.com/dm/atcl/mag/15/398081/071100093/ (searched September 27, 2024), Nanomaterials 2021, 11(2), 537; https://doi.org/10.3390/nano11020537, etc. As shown by the arrows in Figure 5, the dielectric constant and dielectric dissipation factor move downward to the left, indicating better dielectric properties.

Test Example 3
1. Preparation of samples Esterification of xylan-Pr, cellulose-Pr, and α-1,6-glucan-Pr was carried out using carboxylic anhydride, dimethylacetamide (DMAc), and lithium chloride (LiCl) as follows. 0.5 g of dried polysaccharide was added to 100 ml of DMAc in which 8 g of LiCl was dissolved, and the mixture was stirred in an oil bath at 70°C for 3 hours. 20 ml of any carboxylic anhydride was added, and the mixture was stirred in an oil bath at 70°C for 24 hours. After the reaction, a brown, transparent, homogeneous solution was obtained. The reaction solution was poured into a mixed solvent of 500 ml of methanol and water, and the target product was precipitated and collected by filtration. The collected white precipitate was dissolved in 50 ml of chloroform and washed. The chloroform solution was reprecipitated in a mixed solvent of methanol and water, and collected by filtration. The mixture was dried at room temperature and pressure for 2 days, and finally dried in vacuum for 6 hours.

2. Measurement of various physical properties
(1) Measurement of Dielectric Constant (Dk) The dielectric constant of the sample was measured in the same manner as in Test Example 1.

(2) Measurement of dielectric loss tangent (Df) The dielectric loss tangent of the sample was measured by the following measurement method. An E4991B impedance analyzer (Keysight) was used. The test piece was a cast film of 2 cm square with a thickness of 300 μm to 500 μm. The test temperature was 23° C., and the measurement frequency was 1 MHz to 1 GHz.

3. Results Xylan-Pr (reference example) is a compound synthesized by esterifying the hydroxyl groups of β-1,4-xylan with propionic acid. As shown in Figure 6, the dielectric constant of xylan-Pr was lower than that of α-1,6-glucan-Pr. This is thought to be because xylan has fewer hydroxyl groups in the monosaccharide unit than α-1,6-glucan, resulting in relatively small polarization of orientation. The dielectric loss tangent of xylan-Pr was lower than that of cellulose-Pr and was comparable to that of α-1,6-glucan-Pr.

As shown in Figure 7, xylan-Pr has a lower dielectric constant than polyimide, liquid crystal polymer, cellulose-Pr, and α-1,6-glucan-Pr, and a dielectric dissipation factor comparable to that of α-1,6-glucan-Pr. As shown by the arrows in Figure 7, the dielectric constant and dielectric dissipation factor move downward to the left, indicating superior dielectric properties.

Claims (12)

A polysaccharide derivative having a structure in which a plurality of monosaccharide units are polymerized, in which some or all of the hydrogen atoms of the hydroxyl groups of some or all of the monosaccharide units in the plurality of monosaccharide units are substituted with -C(O)-( _CH2 ) _m - ^R1 (1) (wherein each ^R1 may be the same or different and is a substituted or unsubstituted straight-chain or branched-chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6) or -( _CH2 ) _m - ^R2 (2) (wherein each ^R2 may be the same or different and is a substituted or unsubstituted straight-chain or branched-chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and m is 0 to 6), which is any of the following (i) to (iii):
(i) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group. (ii) A glucan derivative in which the monosaccharide unit is glucose, each R ¹ may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted linear or branched hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. (iii) A glucan derivative in which the monosaccharide unit is xylose, and each R A xylan derivative not having a primary hydroxyl group in a side chain, wherein R ¹ may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and each R ² may be the same or different and is a substituted or unsubstituted branched chain hydrocarbon group, a substituted or unsubstituted cyclic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. The polysaccharide derivative according to claim ¹ , which is a glucan derivative having a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and in which some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units are substituted with -C(O)-(CH ₂ ) _m -R 1 (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and m is 0 to 6) or -(CH ₂ ) _m -R ² (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and m is 0 to 6). The polysaccharide derivative according to claim 2, wherein the glycosidic bond includes an α-1,3-glycosidic bond, an α-1,6-glycosidic bond, a β-1,3-glycosidic bond, or a β-1,4-glycosidic bond. The polysaccharide derivative according to claim 1 , wherein the cyclic hydrocarbon group of R ¹ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The polysaccharide derivative according to claim 1, wherein the alicyclic hydrocarbon group is a monocyclic alicyclic hydrocarbon having 3 to 12 ring members. The polysaccharide derivative according to claim 1, which is crystalline. The polysaccharide derivative according to any one of claims 1 to 6, which has a glass transition point of 200°C or higher and a dielectric constant of 3.0 or lower. A grafted glucan derivative in which a second glucan derivative different from the first glucan derivative is grafted to a first glucan derivative, each of the first glucan derivative and the second glucan derivative has a structure in which a plurality of glucose units are polymerized through glycosidic bonds, and some or all of the hydrogen atoms of the hydroxyl groups of some or all of the glucose units of the first glucan derivative and the second glucan derivative are substituted with -C(O)-(CH ₂ ) _m -R ¹ (1) (wherein each R ¹ may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6) or -(CH ₂ ) _m -R ² (2) (wherein each R ² may be the same or different and is a substituted or unsubstituted cyclic hydrocarbon group or a substituted or unsubstituted heterocyclic group, m is 0 to 6). A resin composition containing one or more of the polysaccharide derivatives described in any one of claims 1 to 7 or the glucan derivatives described in claim 8. A molded article obtained by molding the polysaccharide derivative according to any one of claims 1 to 7, the glucan derivative according to claim 8, or the resin composition according to claim 9. The molded article according to claim 10, which is a film. A circuit board material comprising the polysaccharide derivative according to any one of claims 1 to 7, the glucan derivative according to claim 8, or the resin composition according to claim 9.

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