JP2011195788A - Cellulose derivative and method of manufacturing cellulose derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable simple synthesis of a cellulose derivative having preferable thermoplasticity and heat resistance.SOLUTION: The method of manufacturing a cellulose derivative includes (A) a hydrocarbon group, (B) a group including an acyl group: -CO-Rand an alkyleneoxy group: -R-O-2, (wherein Ris a hydrocarbon group, and Ris an alkylene group), and (C) an acyl group: -CO-R, (wherein Ris a hydrocarbon group) as a substituent while satisfying following formulae: DS(A)=0 to 2.2, MS(B)=0.1 to 1.9, and DS(C)=0.5 to 1.7, (wherein DS(A) and DS(C) are each a degree of substitution of the substituents (A) and (C), and MS(B) is a degree of molar substitution of the substituent (B)). The method includes (1) a first step of obtaining an alkali cellulose by reacting at least 2.0 mol equivalent of a base per anhydrous glucose unit of the cellulose, (2) a second step of obtaining a cellulose ether by reacting at least 2.0 mol equivalent of a halogenated hydrocarbon and at least 0.1 mol equivalent of an alkylene oxide per anhydrous glucose unit of the cellulose, and (3) a third step of esterifying the cellulose ether.

Description

  The present invention relates to a novel cellulose derivative and a method for producing a cellulose derivative.

  Various materials are used for members constituting electric and electronic devices such as copiers and printers in consideration of characteristics and functions required for the members. For example, PC (Polycarbonate) resin, ABS (Acrylonitrile-butadiene-styrene) resin, PC / ABS, etc. are used as members (housings) that house a drive machine for electric / electronic devices and protect the drive machine. It is generally used in large quantities (Patent Document 1). These resins are synthesized from compounds made from petroleum.

  Petroleum and other fossil resources are mainly composed of carbon that has been fixed deep underground for many years. When such fossil resource-based products are incinerated and carbon dioxide is released into the atmosphere, carbon that originally did not exist in the atmosphere will be rapidly released as carbon dioxide, resulting in global warming. Contributes to Therefore, PC resin, ABS resin, and the like have excellent characteristics as materials for members for electric and electronic devices, but are not preferable from the viewpoint of global warming because they use fossil resources as raw materials.

  In contrast, plants are produced by photosynthesis using carbon dioxide and water in the atmosphere as raw materials. Therefore, even if the resin obtained from plants is incinerated and carbon dioxide is generated, it is considered that the total amount of carbon dioxide in the atmosphere does not increase or decrease because the carbon dioxide is equivalent to carbon dioxide originally in the atmosphere. it can. From this point of view, plant-derived resins are referred to as so-called “carbon neutral” materials. Currently, it is an urgent need to use plant-derived resins instead of petroleum-derived resins in order to prevent global warming.

  For example, a method of reducing the amount of petroleum used by using plant-derived resources such as starch as a part of the raw material of PC resin has been proposed (Patent Document 2). However, the amount of reduction is insufficient with this method, and development of a resin that reduces the amount of petroleum used is further demanded.

JP-A-56-55425 JP 2008-24919 A

The present inventors have focused on using cellulose as a carbon neutral resin. However, since cellulose generally does not have thermoplasticity, it is difficult to mold by heating or the like, and thus is not suitable for molding. Moreover, even if thermoplasticity can be provided, there exists a problem that it is inferior to heat resistance.
In addition, when a synthetic reaction is performed using cellulose as a raw material to process it into a new cellulose derivative, it is necessary to significantly change the reaction conditions for each synthetic reaction. This is because cellulose is generally known as a resin that does not easily react. Therefore, when going through a plurality of steps, it is necessary to take out the cellulose reactant for each step, and then change the vessel to a different reaction system to perform the reaction step. For example, the etherification and esterification of cellulose are generally carried out under a base and an acid, respectively, as an industrial production method. After performing one reaction system, it is necessary to take out a reactant once and to perform a reaction in a different reaction system (for example, a reaction system of a basic solvent to a reaction system of an acidic solvent). For this reason, the process of a cellulose takes an effort, an installation becomes large, and it is industrially disadvantageous.
An object of the present invention is to provide a production method for easily producing a cellulose derivative having good thermoplasticity and heat resistance and suitable for molding.

The said subject can be achieved by the following means.
<1> a group containing (A) a hydrocarbon group, (B) an acyl group: —CO—R _B1 and an alkyleneoxy group: —R _B2 —O— (R _B1 represents a hydrocarbon group, and R _B2 represents an alkylene group) And (C) acyl group: —CO—R _C (R _C represents a hydrocarbon group) as a substituent, and a method for producing a cellulose derivative satisfying the following formula:
DS (A) = 0-2.2, MS (B) = 0.1-1.9, DS (C) = 0.5-1.7
[Wherein DS (A) and DS (C) represent the degree of substitution of substituents (A) and (C), respectively, and MS (B) represents the degree of molar substitution of substituent (B).
(1) a first step of obtaining alkali cellulose by reacting cellulose with at least 2.0 molar equivalent of base per anhydroglucose unit of the cellulose;
(2) a second step of obtaining cellulose ether by reacting the alkali cellulose with at least 2.0 molar equivalent of halogenated hydrocarbon and at least 0.1 molar equivalent of alkylene oxide per anhydroglucose unit of the cellulose; And (3) A method for producing a cellulose derivative, comprising a third step of esterifying the cellulose ether.
<2> The method for producing a cellulose derivative according to <1>, wherein the third step is performed after the second step without removing the cellulose ether from the reaction vessel.
<3> The method for producing a cellulose derivative according to <1> or <2>, wherein the base used in the first step is a strong base.
<4> The cellulose according to <1>, wherein DS (A) = 1.2 to 2.2, MS (B) = 0.1 to 1.0, and DS (C) = 0.5 to 1.7. A method for producing a derivative.
<5> The cellulose according to <1>, wherein DS (A) = 1.2 to 2.2, MS (B) = 0.1 to 0.6, and DS (C) = 0.7 to 1.7. A method for producing a derivative.
<6> The cellulose according to <1>, wherein DS (A) = 1.2 to 1.6, MS (B) = 0.1 to 0.3, and DS (C) = 1.0 to 1.7. A method for producing a derivative.
<7> The method for producing a cellulose derivative according to any one of <1> to <6>, wherein (B) R _B2 has 2 to 4 carbon atoms.
<8> The method for producing a cellulose derivative according to any one of <1> to <7>, wherein the hydrocarbon group (A) has 1 to 3 carbon atoms.
<9> The method for producing a cellulose derivative according to any one of <1> to <8>, wherein (C) _RC has 1 to 4 carbon atoms.

  In the method for producing a cellulose derivative of the present invention, a cellulose derivative having a good molded piece appearance and rigidity can be easily synthesized.

  Below, the manufacturing method of the cellulose derivative of this invention and the cellulose derivative manufactured by this manufacturing method are demonstrated in detail.

<Method for producing cellulose derivative>

  The method for producing a cellulose derivative of the present invention includes a first step of obtaining alkali cellulose by reacting cellulose with at least 2.0 molar equivalent of a base per anhydroglucose unit of the cellulose. The alkali cellulose obtained in the first step is reacted with at least 2.0 molar equivalent of halogenated hydrocarbon and at least 0.1 molar equivalent of alkylene oxide per anhydroglucose unit of the cellulose to obtain a cellulose ether. Includes two steps. By passing through the first step of alkalinization and the second step of etherification reaction with excess halogenated hydrocarbon and alkylene oxide, the subsequent esterification can be carried out without taking out from the reaction vessel. In this invention, the cellulose derivative which has favorable heat resistance etc. can be manufactured by taking out reaction of a cellulose, without taking out a reaction system from reaction container.

[First step]
The first step of the present invention is a step of obtaining alkali cellulose by reacting cellulose with at least 2.0 molar equivalent of base per anhydroglucose unit of the cellulose.

  The method for producing a cellulose derivative of the present invention is preferably made of cellulose as a raw material, and can be etherified and esterified without taking out the cellulose from the reaction vessel. The raw material of cellulose is not limited, and examples thereof include cotton, linter (for example, cotton linter), and pulp (for example, wood pulp).

  In the step of alkalizing the cellulose derivative of the present invention into alkali cellulose, a base is used. As the base, any of a known weak base and strong base can be used, but it is preferable to use a strong base.

  For example, alkali hydroxide is used as the strong base. As the alkali hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide and the like are used, and sodium hydroxide is preferable. Moreover, although alkali hydroxide is used as aqueous solution, the density | concentration is 10 weight% or more, More preferably, it is 20-80 weight%.

  As the amount of the base to be alkalized, an excess base is added. This is because esterification is performed without taking out from the reaction vessel after etherification described later. As the addition amount of the base to be alkalized, it is necessary to add at least 2.0 molar equivalent of base per anhydroglucose unit of cellulose to be reacted. More specifically, the amount of the base to be added is preferably 2.0 to 10.0 molar equivalents, more preferably 3.0 to 10.0 molar equivalents, and most preferably 6.0 to 10.0 molar equivalents.

  The reaction temperature in the first step is preferably 5 to 70 ° C, more preferably 20 to 50 ° C, from the viewpoint of viscosity and reaction rate of the cellulose reaction solution, and further preferably 20 to 50 ° C.

  The reaction time in the first step is preferably 0.5 to 2 hours, and preferably 0.5 to 1 hour in order to suppress the generation of by-products.

  The 1st process in this invention may be performed only once in the manufacturing method of this invention, and may be performed in multiple times. In the case of performing the treatment a plurality of times, it is sufficient that the target alkali cellulose is obtained after all the first steps are completed.

  The solvent for the first step in the present invention is not limited, but water is preferred. The first step and the second step are preferably performed in a reaction system in which a two-phase system of a solvent and a water / organic solvent in the second step described later is formed.

  The pressure in the present invention is not limited, but is preferably such that the pressure naturally rises due to sealing or overheating, specifically 0.1 to 5.0 MPa is preferable, and 0.1 to 3.5 MPa is more preferable. Preferably, 0.1 to 2.5 MPa is more preferable.

  The alkali cellulose obtained in the first step is a state in which the hydroxyl group of cellulose is dissociated (for example, cellulose sodium alcoholate when used with sodium hydroxide).

[Second step]
In the second step, the alkali cellulose obtained in the first step is reacted with at least 2.0 molar equivalent of halogenated hydrocarbon and at least 0.1 molar equivalent of alkylene oxide per anhydroglucose unit of the cellulose. It refers to the process of obtaining cellulose ether.

  In the step of etherifying the alkali cellulose obtained in the first step, a halogenated hydrocarbon and an alkylene oxide are used. Although a 2nd process is performed after a 1st process, you may insert another process suitably after a 1st process. The other process may be, for example, a cooling process or a reaction that introduces another substituent.

Halogenated hydrocarbons can be used to etherify cellulose. Specific halogenated _{hydrocarbons, C n H 2n + 1 -X} (X is fluorine, chlorine, bromine, halogen iodine) halogenated hydrocarbon or its derivative represented by are preferred. Specifically, n is preferably 1 to 4, more preferably 1 to 3, and most preferably 1 to 2.

  As the addition amount of the halogenated hydrocarbon used in the second step, an excess of halogenated hydrocarbon is used relative to the raw material cellulose. This is because esterification is performed without taking out from the reaction vessel after etherification described later. As the addition amount of the halogenated hydrocarbon, it is necessary to add 2.0 mol equivalent or more of the halogenated hydrocarbon per anhydroglucose unit to be reacted. More specifically, the amount of the halogenated hydrocarbon to be added is preferably 2.0 to 10 molar equivalents, more preferably 3.0 to 10 molar equivalents, and most preferably 6.0 to 9.0 molar equivalents.

  Alkylene oxide is used to etherify the cellulose. Carbon number of alkylene oxide is 1-7, for example, More specifically, 1-5 are preferable and 1-4 are still more preferable. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide and the like.

  As the addition amount of the alkylene oxide used in the second step, it is necessary to add an alkylene oxide of 0.1 molar equivalent or more per anhydroglucose unit to be reacted. More specifically, the amount of alkylene oxide to be added is preferably 0.1 to 8.0 molar equivalent, more preferably 0.2 to 5.0 molar equivalent, and most preferably 0.3 to 3.0 molar equivalent. .

  The reaction temperature in the second step is preferably 40 to 130 ° C, more preferably 50 to 120 ° C. When the temperature is 40 ° C. or higher, the diffusion rate of the etherifying agent is increased, which is preferable from the viewpoint of reactivity. From the viewpoint of the internal pressure of the reaction system, it is preferable that the temperature is 130 ° C. or lower because side reactions are suppressed.

  The reaction time in the second step is preferably 4 to 10 hours, more preferably 6 to 8 hours as a total time. The reaction time in the third step is preferably 3 to 12 hours, and more preferably 4 to 8 hours.

  The 2nd process in this invention may be performed only once in the manufacturing method of this invention, and may be performed in multiple times. In the case of performing the treatment a plurality of times, it is sufficient that the target cellulose ether is obtained after all the second steps are completed.

  As the solvent in the second step, an aromatic hydrocarbon solvent such as benzene or toluene is used. From the viewpoint of lowering the vapor pressure of the halogenated hydrocarbon during etherification, toluene is particularly preferably used. The solvent in the second step may be one type or two types, but preferably forms a two-phase system.

The compound obtained in the second step is, for example, cellulose ether or hydroxyalkyl cellulose in which a hydrogen atom of a hydroxyl group contained in cellulose is substituted with an alkyl group having 1 to 4 carbon atoms.
Specific examples include methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, allyl cellulose, hydroxyethyl cellulose, and hydroxymethyl cellulose.

  The unreacted alkylene oxide in the second step may be present in the form of a polyol.

[Third step]
A 3rd process means the process of esterifying the cellulose ether obtained at the 2nd process.
The cellulose ether obtained in the second step is esterified in the third step without being taken out from the reaction vessel. In the esterification step, a base and an acid anhydride are used. Although the third step is performed after the second step, other steps may be appropriately added after the second step.

  As the base for esterifying cellulose, for example, amines such as pyridine, lutidine, dimethylaminopyridine, triethylamine, diethylbutylamine, diazabicycloundecene, alkali metal carbonates such as potassium carbonate, triethylamine and the like are used. be able to. Of these, amines such as pyridine, dimethylaminopyridine, and triethylamine are preferable.

  The addition amount of the base for esterifying cellulose is preferably 2.0 to 10.0 molar equivalents relative to the cellulose ether obtained in the second step.

  As the acid anhydride, for example, a carboxylic acid anhydride composed of a carboxylic acid having 4 to 18 carbon atoms can be used. Examples of such carboxylic anhydrides include acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, hexanoic anhydride, heptanoic anhydride, octanoic anhydride, 2-ethylhexanoic anhydride. Nonanoic acid anhydride, decanoic acid anhydride, lauric acid anhydride, myristic acid anhydride, palmitic acid anhydride, stearic acid anhydride, propionic acid anhydride and the like. Particularly preferred are acetic anhydride, butyric anhydride, propionic anhydride and the like.

  The amount of acid anhydride added is preferably 2.0 to 10.0 molar equivalents.

  The reaction temperature in the third step is preferably 20 to 70 ° C, and more preferably 30 to 60 ° C. When it is 20 degrees or more, the diffusion rate of the esterifying agent is increased, which is preferable from the viewpoint of reactivity. It is preferable that the temperature is 70 ° C. or lower because side reactions are suppressed.

  The 3rd process in this invention may be performed only once in the manufacturing method of this invention, and may be performed in multiple times. In the case of performing the treatment a plurality of times, it is sufficient that the target cellulose derivative is obtained after all the third steps are completed.

[Cellulose derivative]
The cellulose derivative obtained by the production method of the present invention is
A) a hydrocarbon group,
B) an acyl group: _{-CO-R B1} and an alkyleneoxy _group: group _{(R B} including the _-R B2 -O- represents a hydrocarbon group), and C) an acyl group:. _-CO-R C _{(R C} represents a hydrocarbon group.)
Have
That is, in the cellulose derivative in the present invention, at least a part of the hydrogen atoms of the hydroxyl group contained in cellulose {(C ₆ H ₁₀ O ₅ ) _n } is A) a hydrocarbon group, B) an acyl group (—CO—). R _B ) and an alkyleneoxy group (—R _B2 —O—) and the C) acyl group (—CO—R _C ).
More specifically, the cellulose derivative in the present invention has a repeating unit represented by the following general formula (2).

General formula (2)

In the above formula, R ² , R ³ and R ⁶ are each independently a hydrogen atom, A) a hydrocarbon group, B) an acyl group (—CO—R _B ) and an alkyleneoxy group (—R _B2 —O—). And C) an acyl group (—CO—R _C ). R _B and R _C represent a hydrocarbon group. ^However, R 2, ^{R 3,} and at least a portion of the ^{R 6} represents a hydrocarbon ^group, R 2, ^{R 3,} and at least part of an acyl group _{(-CO-R B)} an alkylene group of ^{R 6} ( -R _B2 -O-), and at least part of R ² , R ³ , and R ⁶ represents an acyl group (-CO-R _C ). These organic groups may be substituted or unsubstituted.

As described above, in the cellulose derivative of the present invention, at least a part of the hydroxyl groups of the β-glucose ring is A) a hydrocarbon group, B) an acyl group (—CO—R _B ) and an alkyleneoxy group (—R _B2 —O—). ), And C) an ether group and an ester group by an acyl group (—CO—R _C ), can exhibit thermoplasticity and can be suitable for molding processing. .
In addition, this cellulose derivative can exhibit excellent strength and heat resistance as a molded body, and is particularly useful as a thermoforming material. Furthermore, since cellulose is a completely plant-derived component, it is carbon neutral and can greatly reduce the burden on the environment.

  The “cellulose” referred to in the present invention is a polymer compound in which a large number of glucoses are bonded by β-1,4-glycosidic bonds, and the carbon atoms at the 2nd, 3rd and 6th positions in the glucose ring of cellulose. Means that the hydroxyl group bonded to is unsubstituted. Further, “hydroxyl group contained in cellulose” refers to a hydroxyl group bonded to carbon atoms at the 2nd, 3rd and 6th positions in the glucose ring of cellulose.

The cellulose derivative has a group containing A) a hydrocarbon group, B) an acyl group (—CO—R _B ) and an alkyleneoxy group (—R _B2 —O—) in any part of the whole, and C ) An acyl group (—CO—R _C ) may be contained, and may be composed of the same repeating unit, or may be composed of a plurality of types of repeating units. Further, the cellulose derivative need not contain all the substituents of A) to C) in one repeating unit.
As a more specific aspect, for example, when there are two types of alkyleneoxy groups of the cellulose derivative, the following aspects are exemplified.
(1) A part of R ² , R ³ and R ⁶ is
A) a repeating unit substituted with a hydrocarbon group;
A repeating unit in which a part of R ² , R ³ and R ⁶ is substituted with a group containing B) an acyl group (—CO—R _B ) and an alkyleneoxy group (—R _B2 —O—);
A repeating unit in which a part of R ² , R ³ and R ⁶ is substituted with C) an acyl group (—CO—R _C );
Cellulose derivative composed of
(2) One of R ² , R ³ and R ⁶ of one repeating unit is
A) a hydrocarbon group,
B) a group containing an acyl group (—CO—R _B ) and an alkyleneoxy group (—R _B2 —O—), and
C) Acyl group (—CO—R _C )
A cellulose derivative composed of the same type of repeating unit substituted with (that is, having all of the substituents A) to C) in one repeating unit).
(3) A cellulose derivative in which repeating units having different substitution positions and different types of substituents are bonded at random.
Further, a part of the cellulose derivative may contain an unsubstituted repeating unit (that is, a repeating unit in which R ² , R ³ and R ⁶ are all hydrogen atoms in the general formula (1)).

The hydrocarbon group as A) may be either an aliphatic group or an aromatic group. In the case of an aliphatic group, it may be linear, branched or cyclic, and may have an unsaturated bond. Examples of the aliphatic group include an alkyl group, a cycloalkyl group, an alkenyl group, and an alkynyl group. Examples of the aromatic group include a phenyl group, a naphthyl group, a phenanthryl group, and an anthryl group.
The hydrocarbon group as A) is preferably an aliphatic group, more preferably an alkyl group, and still more preferably an alkyl group having 1 to 4 carbon atoms (lower alkyl group). Specifically, it is preferably a methyl group, an ethyl group, or a propyl group, more preferably a methyl group or an ethyl group, and most preferably a methyl group.

In the acyl group (—CO—R _B1 ) in _B ), R _B1 represents a hydrocarbon group. R _B1 may be either an aliphatic group or an aromatic group. In the case of an aliphatic group, it may be linear, branched or cyclic, and may have an unsaturated bond. Examples of the aliphatic group and the aromatic group include those described above.
R _B1 is specifically an alkyl group or an aryl group. The alkyl group or aryl group is specifically an alkyl group or aryl group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 2 to 4 carbon atoms. And most preferably an alkyl group having 3 carbon atoms (that is, a propyl group).
Specifically, as R _B1 , methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, tert-butyl group, isoheptyl group and the like Is mentioned. Preferably, R _B is ethyl group, a propyl group, most preferably a propyl group.

The group containing an acyl group (—CO—R _B1 ) and an alkyleneoxy group (—R _B2 —O—) as _B ) is a group containing a structure represented by the following general formula (1). preferable.

General formula (1)

In the formula, R _B2 represents an alkylene group, which may include a plurality of alkyleneoxy groups (—R _B2 —O—), or may include only one. x represents an integer of 1 to 10, preferably x = 1 to 5, and more preferably x = 1 to 3.

  More specifically, the group of B) can be represented by the following general formula (1 ′) or general formula (1 ″). In the formula, n independently represents an integer of 2 to 4, preferably 2 Represents an integer of ˜3, m independently represents an integer of 1 to 4, and preferably represents an integer of 1 to 3;

General formula (1 ')

  [Wherein, x represents an integer of 1 to 5, preferably an integer of 1 to 3. ]

  General formula (1 ")

  [Wherein, x represents an integer of 1 to 5, preferably an integer of 1 to 3. ]

In the formula, R _B1 has the same meaning as described above, and the preferred range is also the same. The upper limit of n is not particularly limited, and varies depending on the amount of alkyleneoxy group introduced, but is about 10, for example.
In the cellulose derivative of the present invention, a group of B) containing only one alkyleneoxy group (a group in which n is 1 in the above formula (1 ′)) and B) containing two or more alkyleneoxy groups And a group (a group in which n is 2 or more in the above formula (1 ′)) may be mixed and contained.

In previous period C) as acyl group _{(-CO-R C), R} C represents a hydrocarbon group. As the hydrocarbon group represented by R _{C, the same} groups as those described above for R _B1 can be used. The preferred range of R _C is the same as R _B1 .

The hydrocarbon group as A), the hydrocarbon group represented by R _B1 and R _C , and the alkylene group may have a further substituent or may be unsubstituted, but may be unsubstituted. preferable.
In particular, when R _B1 and R _C have a further substituent, it is preferable not to include a substituent that imparts water solubility, such as a sulfonic acid group or a carboxyl group. By not containing these groups, a cellulose derivative insoluble in water and a molding material comprising them are obtained.

When the hydrocarbon group, R _B1 , R _C , and the alkylene group as A) have a further substituent, examples of the further substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom) , A hydroxy group, an alkoxy group (the alkyl group portion preferably has 1 to 5 carbon atoms), an alkenyl group, and the like. In addition, when said R is other than an alkyl group, it can also have an alkyl group (preferably C1-C5) as a substituent.

Moreover, when using the cellulose derivative in this invention as a molding material, since it is preferable that it is water-insoluble, it is preferable not to have substantially water-soluble substituents, such as a carboxyl group. When the cellulose derivative does not substantially have a carboxyl group, it can be made water-insoluble and more suitable for molding.
Here, “substantially has no carboxyl group” means not only when the cellulose derivative in the present invention has no carboxyl group, but also in a range in which the cellulose derivative in the present invention is insoluble in water. Including the case where it has. For example, a cellulose which is a raw material may contain a carboxyl group, and a cellulose derivative in which the substituents A) to C) are introduced using this may contain a carboxyl group. In a cellulose derivative substantially free of
Further, “water insoluble” means that the solubility in 100 parts by mass of water at 25 ° C. is 5 parts by mass or less.

In the cellulose derivative, A) a hydrocarbon group, B) a group containing an acyl group (—CO—R _B1 ) and an alkyleneoxy group (—C _n H _2n —O—), and C) an acyl group (—CO—R). _C )) and the number of substitution groups per β-glucose ring unit (substitution degree) are DS (A) = 0 to 2.2, MS (B) = 0.1 to 1.9, DS (C) = 0.5 to 1.7.

For example, A) the degree of substitution DS (A) of the hydrocarbon group (A) the number of the hydrocarbon groups with respect to the hydroxyl groups at the 2-position, 3-position and 6-position of the β-glucose ring in the repeating unit) is from 0 to 2.2. It is preferable that it is 1.2-2.2, and it is most preferable that it is 1.2-1.6.
B) Degree of substitution DS (B) of a group containing an acyl group (—CO—R _B ) and an alkyleneoxy group (—C _n H _2n —O—) (in the repeating unit, 2 of the cellulose structure of the β-glucose ring) It is preferable that B) the number of groups containing an acyl group and an ethyleneoxy group with respect to the hydroxyl groups at the 3rd and 6th positions is 0 <DS (B). Since 0 <DS (B), the melting start temperature can be lowered, so that thermoforming can be performed more easily.
C) Degree of substitution DS (C) of acyl group (—CO—R _C ) (C) in the repeating unit, C) of the cellulose structure of the β-glucose ring, C) the number of acyl groups relative to the hydroxyl groups at positions 3, 3 and 6. 0.1 <DS (C). Specifically, 0.5 to 1.7 is preferable, 0.7 to 1.7 is more preferable, and 1.0 to 1.7 is most preferable.

  Further, the number of unsubstituted hydroxyl groups present in the cellulose derivative is not particularly limited. The substitution degree DSh of hydrogen atoms (ratio in which the hydroxyl groups at the 2-position, 3-position and 6-position in the polymerization unit are unsubstituted) can be in the range of 0 to 1.5, preferably 0 to 0.6. can do. By setting DSh to 0.6 or less, it is possible to improve the fluidity of the thermoforming material, or to accelerate the thermal decomposition and suppress foaming due to water absorption of the thermoforming material during molding.

The cellulose derivative in the present invention includes A) a hydrocarbon group, B) a group containing an acyl group (—CO—R _B ) and an alkyleneoxy group (—C _n H _2n —O—), and C) acyl. You may have substituents other than group (-CO-R < _C >). Examples of the substituent that may be included include a hydroxyethyl group, a hydroxyethoxyethyl group, and a hydroxyethoxyethoxyethyl group. Therefore, the total sum of the degree of substitution of all substituents of the cellulose derivative is 3, but (DS (A) + DS (B) + DS (C) + DS _h ) is 3 or less.

In addition, the amount of alkyleneoxy group (—C _n H _2n —O—) introduced into the group B) is represented by the molar substitution degree (MS: the number of moles of substituent introduced per glucose residue) (Cellulose Society of Japan). Edit, Cellulose Dictionary P142). The molar substitution degree MS (B) of the alkyleneoxy group is preferably 0 <MS (B), more preferably 0.1 to 1.9, and more preferably 0.1 to 1.0. More preferred is 0.1 to 0.6.

The molecular weight of the cellulose derivative is preferably a number average molecular weight (Mn) in the range of 5 × 10 ^{3 to} 1000 × 10 ³ , more preferably in the range of 10 × 10 ^{3 to} 800 × 10 ³ , and 10 × 10 ^{3 to} 500 × 10. A range of ³ is most preferred. The weight average molecular weight (Mw) is preferably in the range of 7 × 10 ^{3 to} 10000 × 10 ³ , more preferably in the range of 100 × 10 ^{3 to} 5000 × 10 ³ , and in the range of 500 × 10 ^{3 to} 5000 × 10 ³ . Is most preferred. By setting the average molecular weight within this range, it is possible to improve the moldability and mechanical strength of the molded body.
The molecular weight distribution (MWD) is preferably in the range of 1.1 to 10.0, and more preferably in the range of 2.0 to 8.0. By setting the molecular weight distribution within this range, moldability and the like can be improved.
In the present invention, the number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (MWD) can be measured using gel permeation chromatography (GPC). Specifically, N-methylpyrrolidone can be used as a solvent, a polystyrene gel can be used, and the molecular weight can be obtained using a conversion molecular weight calibration curve obtained in advance from a constituent curve of standard monodisperse polystyrene.

The use of the cellulose derivative obtained in the present invention is not particularly limited. For example, as a molded body, the interior or exterior of an electric / electronic device (home appliance, OA / media related device, optical device, communication device, etc.) is used. Examples include parts, automobiles, machine parts, housing and building materials. Among these, from the viewpoint of having excellent heat resistance and low environmental impact, for example, it is suitable as an exterior component (especially a casing) for electrical and electronic equipment such as a copying machine, a printer, a personal computer, and a television. Can be used.
If necessary, the molded body may be filled with fillers, flame retardants, other polymers, plasticizers, stabilizers (antioxidants, UV absorbers, etc.), mold release agents, antistatic agents, flame retardant aids, processing aids. Various additives such as a colorant including an agent, an anti-drip agent, an antibacterial agent, an antifungal agent, and a dye or pigment may be contained.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the scope of the present invention is not limited to the examples shown below.

<Synthesis Example 1: Synthesis of P-1>
100 g of pulverized pulp, sodium hydroxide aqueous solution (148 g of sodium hydroxide / 150 mL of water, 6.1 molar equivalents per anhydroglucose unit of cellulose) in an autoclave (manufactured by pressure-resistant glass industry, simplified autoclave TEM-D3000M), nitrogen The mixture was stirred at 45 ° C. for 1 hour under the atmosphere (first step). After standing to cool, it was cooled to −40 ° C. with a dry ice / methanol bath, and further 150 mL of toluene, 186 g of chloromethane (6 molar equivalents per anhydroglucose unit of cellulose), 20 g of propylene oxide (0.6 per anhydroglucose unit of cellulose) (Molar equivalent) was added, and the mixture was stirred at 60 ° C. for 1 hour and at 90 ° C. for 6 hours (second step). After returning to room temperature, the residual gas in the system was exhausted, and 300 mL of acetic anhydride and 150 mL of triethylamine were further added, followed by stirring at 50 ° C. for 6 hours. After returning to room temperature, the mixture was poured into 6 L of water with vigorous stirring to obtain a brown solid (third step). The operation of washing the obtained brown solid with 6 L of hot water was repeated 3 times, and further the operation of washing with a mixed solvent of 2 L of methanol / 6 L of water was repeated 3 times to obtain an off-white solid. The obtained off-white solid was separated by suction filtration and vacuum-dried at 100 ° C. for 6 hours to obtain the objective cellulose derivative (P-1, substitution degree, molecular weight described in Table 1) as off-white powder ( Yield 145 g).

<Synthesis Example 2: Synthesis of P-2>
In the same manner as in Synthesis Example 1, except that the reaction temperature in the second step was changed to 60 ° C. for 1 hour and 100 ° C. for 6 hours, the target cellulose derivative (P-2, substitution degree and molecular weight are listed in Table 1). Obtained as an off-white powder (yield 138 g).

<Synthesis Example 3: Synthesis of P-3>
In Synthesis Example 2, 222 g of sodium hydroxide used in the first step (9.1 mol equivalent per anhydroglucose unit of cellulose) and 278 g of chloromethane used in the second step (6.1 mol equivalent per anhydroglucose unit of cellulose) The target cellulose derivative (P-3, the degree of substitution and the molecular weight are listed in Table 1) in the same manner except that propylene oxide was changed to 25 g (0.7 molar equivalent per anhydroglucose unit of cellulose) as an off-white powder. Obtained (135 g).

<Synthesis Example 4: Synthesis of P-4>
The same procedure was performed except that chloromethane used in the second step in Synthesis Example 1 was changed to 235 g of chloroethane (6 molar equivalents per anhydroglucose unit of cellulose), and the reaction temperature was changed to 1 hour at 60 ° C and 6 hours at 120 ° C. The target cellulose derivative (P-4, substitution degree, molecular weight is listed in Table 1) was obtained as an off-white powder (148 g).

<Synthesis Example 5: Synthesis of P-5>
It is the same except that the chloromethane used in the second step in Synthesis Example 1 is changed to 450 g of bromopropane (6 molar equivalents per anhydroglucose unit of cellulose), and the reaction temperature is changed to 1 hour at 60 ° C. and 6 hours at 100 ° C. Thus, the objective cellulose derivative (P-5, substitution degree, molecular weight described in Table 1) was obtained as a black-brown powder (163 g).

<Synthesis Example 6: Synthesis of P-6>
In the same manner as in Synthesis Example 4 except that acetic anhydride used in the third step was changed to propionic anhydride, the target cellulose derivative (P-6, substitution degree, molecular weight described in Table 1) was obtained as an off-white powder ( 155g).

<Synthesis Example 7: Synthesis of P-7>
Chloromethane used in the second step in Synthesis Example 3 was changed to 355 g of chloroethane (9 molar equivalents per anhydroglucose unit of cellulose) and propylene oxide was changed to 20 g of butylene oxide (0.5 molar equivalents per anhydroglucose unit of cellulose), The target cellulose derivative (P-7, substitution degree, molecular weight is described in Table 1) was obtained as an off-white powder in the same manner except that the reaction temperature was changed to 60 ° C. for 1 hour and 120 ° C. for 6 hours (128 g). ).

<Synthesis Example 8: Synthesis of P-8>
In Synthesis Example 3, chloromethane used in the second step was changed to 235 g of chloroethane (6 molar equivalents per anhydroglucose unit of cellulose), and the amount of propylene oxide was changed to 60 g (1.7 molar equivalents per anhydroglucose unit of cellulose) Obtained the target cellulose derivative (P-8, substitution degree, molecular weight described in Table 1) as an off-white solid (156 g).

<Synthesis Example of Comparative Compound 1: Synthesis of H-1>
40 g of sodium hydroxide used in the first step in Synthesis Example 1 (1.6 molar equivalents per anhydroglucose unit of cellulose) and 45 g of chloromethane used in the second step (1.5 molar equivalents per anhydroglucose unit of cellulose) In the same manner, except that propylene oxide was changed to 300 g (8.5 molar equivalents per anhydroglucose unit of cellulose) and the reaction temperature was changed to 60 ° C. for 1 hour, 80 ° C. for 3 hours, and 100 ° C. for 3 hours. H-1, substitution degree, and molecular weight described in Table 1) were obtained as a yellowish white amorphous solid (230 g).

<Synthesis Example 2 of Comparative Compound: Synthesis of H-2>
40 g of sodium hydroxide used in the first step in Synthesis Example 1 (1.6 molar equivalents per anhydroglucose unit of cellulose), 290 g of propylene oxide (8.2 molar equivalents per anhydroglucose unit of cellulose), and chloromethane as chloroethane Comparative compound (H-2, 2) was changed in the same manner except that the reaction temperature was changed to 60 g (1.5 molar equivalents per anhydroglucose unit of cellulose) and the reaction temperature was changed to 60 ° C. for 1 hour, 80 ° C. for 3 hours, and 120 ° C. for 3 hours. The degree of substitution and molecular weight described in Table 1) were obtained as a grey-brown amorphous solid (183 g).

<Synthesis Example 3 of Comparative Compound: Synthesis of H-4>
Weighed 100 g of crushed pulp and sodium hydroxide aqueous solution (45 g of sodium hydroxide / 150 mL of water, 1.8 mol per anhydroglucose unit of cellulose) into an autoclave (manufactured by pressure-resistant glass industry, simplified autoclave TEM-D3000M), and nitrogen atmosphere The mixture was stirred at 45 ° C. for 1 hour (first step). After standing to cool, it was cooled to −40 ° C. with a dry ice / methanol bath, and further 150 mL of toluene, 70 g of chloroethane (1.8 mol per anhydroglucose unit of cellulose), 20 g of propylene oxide (0.6 per anhydroglucose unit of cellulose) Mol) was added and stirred at 60 ° C. for 1 hour and 90 ° C. for 6 hours (second step). After returning to room temperature, the residual gas in the system was evacuated, and the contents were poured into 5 L of hot water with vigorous stirring to obtain a gel-like solid. The obtained gel-like solid was filtered while hot, further washed with 5 L of hot water three times, and dried at 100 ° C. for 6 hours to obtain 110 g of a white solid. The obtained white solid was transferred to a 5 L three-necked flask, and 2 L of pyridine was added and dissolved at room temperature. Furthermore, 0.5 L of acetic anhydride was added and reacted at 50 ° C. for 6 hours. After returning to room temperature, the reaction mixture was poured into 10 L of methanol with vigorous stirring to obtain a yellowish white solid. After the obtained yellowish white solid was filtered, the operation of washing with a mixed solvent of methanol / water = 2L / 2L was repeated three times. The obtained yellowish white solid was separated by suction filtration, and vacuumed at 80 ° C. for 6 hours. By drying, the target comparative compound (H-4, substitution degree, molecular weight described in Table 1) was obtained as a yellowish white powder (yield 140 g).

Note that the compound obtained above, a hydroxyl group ^(R 2, ^{R 3} and ^{R 6)} kinds of substituted functional groups contained in the cellulose, and DS and MS, Cellulose Communication 6,73-79 (1999) Table 1 shows the results of observation and determination by ¹ H-NMR or ¹³ C-NMR using the method described in Chality 12 (9), 670-674.

<Measurement of physical properties of cellulose derivative>
Table 1 shows the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the obtained cellulose derivative. These measuring methods are as follows.
[Molecular weight]
For the measurement of the number average molecular weight (Mn) and the weight average molecular weight (Mw), gel permeation chromatography (GPC) was used. Specifically, N-methylpyrrolidone was used as a solvent, a polystyrene gel was used, and the molecular weight was determined using a conversion molecular weight calibration curve obtained in advance from a constituent curve of standard monodisperse polystyrene. As the GPC apparatus, HLC-8220 GPC (manufactured by Tosoh Corporation) was used.

<Example 1: Production of molded body made of cellulose derivative>
[Test specimen preparation]
The cellulose derivative (P-1) obtained above is supplied to an injection molding machine (Imoto Seisakusho, semi-automatic injection molding machine), and the molding temperature (cylinder temperature) and mold temperature shown in Table 1 are set to 60 ° C. Then, a 4 × 10 × 80 mm multipurpose test piece (bending test piece) was molded at an injection pressure of 1.5 kgf / cm ² .

<Examples 2-8, Comparative Examples 1-4>
In the same manner as in Example 1, cellulose derivatives (P-2) to (P-8), comparative compounds (H-1) to (H-2), (H-4) hydroxypropylmethylcellulose (H-3, Matsumoto) Using a fat and oil 90MP4000), a test piece was produced according to the molding conditions shown in Table 1.

<Measurement of physical properties of test piece>
About the obtained test piece, the bending elastic modulus and the molded piece appearance were measured according to the following method. The results are shown in Table 1.
[Flexural modulus (rigidity)]
The bending elastic modulus was measured with a bending tester in accordance with JISK7171.
[Appearance of molded piece]
About the obtained test piece, the molded piece external appearance was sensory-evaluated as follows.
A: Uniform and transparent.
B: Translucent.
C: It is cloudy.
A to B are in a range where there is no problem in practical use.

  As is clear from the results in Table 1, by carrying out the production method of the present invention, a cellulose derivative having a good molded piece appearance and high rigidity (flexural modulus) is taken out from the reaction vessel. It can be seen that a method that can be easily manufactured can be provided.

Claims (9)

(A) a hydrocarbon group,
(B) a group containing an acyl group: —CO—R _B1 and an alkyleneoxy group: —R _B2 —O— (R _B1 represents a hydrocarbon group, R _B2 represents an alkylene group), and
(C) Acyl group: —CO—R _C (R _C represents a hydrocarbon group),
Is a method for producing a cellulose derivative satisfying the following formula,
DS (A) = 0-2.2,
MS (B) = 0.1-1.9,
DS (C) = 0.5 to 1.7
[Wherein DS (A) and DS (C) represent the degree of substitution of substituents (A) and (C), respectively, and MS (B) represents the degree of molar substitution of substituent (B).
(1) a first step of obtaining alkali cellulose by reacting cellulose with at least 2.0 molar equivalent of base per anhydroglucose unit of the cellulose;
(2) a second step of obtaining cellulose ether by reacting the alkali cellulose with at least 2.0 molar equivalent of halogenated hydrocarbon and at least 0.1 molar equivalent of alkylene oxide per anhydroglucose unit of the cellulose; And
(3) A method for producing a cellulose derivative, comprising a third step of esterifying the cellulose ether.   The method for producing a cellulose derivative according to claim 1, wherein the third step is performed after the second step without removing the cellulose ether from the reaction vessel.   The method for producing a cellulose derivative according to claim 1 or 2, wherein the base used in the first step is a strong base.   The production of a cellulose derivative according to claim 1, wherein DS (A) = 1.2 to 2.2, MS (B) = 0.1 to 1.0, DS (C) = 0.5 to 1.7. Method.   The production of a cellulose derivative according to claim 1, wherein DS (A) = 1.2 to 2.2, MS (B) = 0.1 to 0.6, and DS (C) = 0.7 to 1.7. Method.   The production of a cellulose derivative according to claim 1, wherein DS (A) = 1.2 to 1.6, MS (B) = 0.1 to 0.3, DS (C) = 1.0 to 1.7. Method. The method for producing a cellulose derivative according to any one of claims 1 to 6, wherein (B) R _B2 has 2 to 4 carbon atoms.   The method for producing a cellulose derivative according to any one of claims 1 to 7, wherein the hydrocarbon group (A) has 1 to 3 carbon atoms. 9. The method for producing a cellulose derivative according to claim 1, wherein (C) _RC has 1 to 4 carbon atoms.