WO2011078291A1

WO2011078291A1 - Molding material, molded article and process for production thereof, and housing for electric/electronic device

Info

Publication number: WO2011078291A1
Application number: PCT/JP2010/073246
Authority: WO
Inventors: 俊英芳谷; 上平　茂生
Original assignee: 富士フイルム株式会社
Priority date: 2009-12-25
Filing date: 2010-12-22
Publication date: 2011-06-30
Also published as: JP2011132463A; JP5486918B2

Abstract

Disclosed are: a molding material having high stiffness (bending elastic modulus), good bending strength, a high thermal deformation temperature and excellent moldability and also having good impact resistance (Charpy impact strength) and dimensional stability; and a molded article. The molding material comprises: a cellulose derivative which contains at least one group that is produced by substituting a hydrogen atom in a hydroxy group contained in a cellulose by a group (A) and at least one group that is produced by substituting a hydrogen atom in a hydroxy group contained in the cellulose by a group (B); and a polystyrene resin. (A) A hydrocarbon group: -R_A. (B) An acyl group: -CO-R_B (wherein R_B represents a hydrocarbon group).

Description

MOLDING MATERIAL, MOLDED BODY, ITS MANUFACTURING METHOD, AND ELECTRIC ELECTRONIC DEVICE CASE

The present invention relates to a molding material, a molded body, a manufacturing method thereof, and a casing for electrical and electronic equipment.

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), ABS (Acrylonitrile-butadiene-styrene) resin, PC / ABS, etc. are generally used as a member (housing) that stores a drive machine for electrical and electronic equipment and protects the drive machine. In large amounts (Patent Document 1). These resins are produced by reacting compounds obtained from petroleum as a raw material.
By the way, fossil resources such as oil, coal, and natural gas are mainly composed of carbon that has been fixed in the ground for many years. When such fossil resources or products made from fossil resources are burned and carbon dioxide is released into the atmosphere, carbon that was originally not deep in the atmosphere but fixed deep in the ground Is rapidly released as carbon dioxide, and carbon dioxide in the atmosphere greatly increases, which causes global warming. Therefore, polymers such as ABS and PC made from petroleum, which is a fossil resource, have excellent characteristics as materials for electrical and electronic equipment, but are made from petroleum, which is a fossil resource. Therefore, it is desirable to reduce the amount used from the viewpoint of preventing global warming.
On the other hand, a plant-derived resin is originally produced by a photosynthesis reaction using carbon dioxide and water in the atmosphere as raw materials. Therefore, even if plant-derived resin is incinerated to generate carbon dioxide, the carbon dioxide is equivalent to carbon dioxide originally in the atmosphere, so the balance of carbon dioxide in the atmosphere is plus or minus zero After all, there is an idea that the total amount of CO _{2 in} the atmosphere is not increased. Based on this idea, plant-derived resins are referred to as so-called “carbon neutral” materials. The use of carbon-neutral materials in place of petroleum-derived resins is an urgent need to prevent global warming in recent years.
For this reason, in PC polymer, the method of reducing petroleum origin resources is proposed by using plant origin resources, such as starch, as some raw materials derived from petroleum (patent documents 2).
However, further improvements are required from the perspective of aiming for a more complete carbon neutral material.

As known cellulose derivatives, hydroxypropylmethylacetylcellulose is described in Patent Document 3 and Patent Document 4. Patent Document 3 and Patent Document 4 describe that this hydroxypropylmethylacetylcellulose is useful as an additive for reducing the vapor pressure of an organic solvent that easily volatilizes. In addition, the substitution degree of each substituent in hydroxypropylmethylacetylcellulose described in Patent Document 3 and Patent Document 4 is, for example, a molar substitution degree (MS) of hydroxypropyl group in a range of about 2 to 8, a substitution degree of methyl group Is in the range of about 0.1 to 1 and the degree of substitution of the acetyl group is in the range of about 0.8 to 2.5.
Further, hydroxypropylmethylpropylcellulose, hydroxypropylmethylbutylcellulose and the like (Patent Document 5), hydroxypropylmethylserose phthalate and the like (Patent Document 6) are disclosed as uses such as drug coating.

Patent Document 7 describes a resin composition containing a cellulose ester, and further describes that it may contain a polystyrene resin or an impact-resistant polystyrene resin.

Japanese Unexamined Patent Publication No. 56-55425 Japanese Unexamined Patent Publication No. 2008-24919 US Pat. No. 3,979,179 U.S. Pat. No. 3,940,384 International Publication No. 09/010837 Japanese Patent No. 3017412 specification Japanese Unexamined Patent Publication No. 2006-111858

The inventors of the present invention 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. Further, even if thermoplasticity can be imparted, there is a problem that strength such as impact resistance is greatly reduced.
For example, the cellulose derivatives described in Patent Documents 3, 4, and 6 are water-soluble or swellable and lack strength, which is not preferable as a molding material. In addition, the cellulose derivative described in Patent Document 5 is described as being poorly water-soluble, but only described in the text, and its synthesis method and usage form are specifically disclosed in Examples and the like. Absent.
Moreover, the resin composition containing the cellulose ester and the polystyrene resin described in Patent Document 7 is inferior in impact resistance and needs to be improved.
Moreover, since the molded object formed using the conventional cellulose derivative is easy to absorb a water | moisture content, improvement is calculated | required from a viewpoint of dimensional stability.

The object of the present invention is performance such as high rigidity (flexural modulus), good bending strength, high heat resistance (thermal deformation temperature), and excellent moldability, and even better impact resistance (Charpy impact strength), And a molding material and a molded body having dimensional stability. Another object of the present invention is to provide a molded body obtained by molding the molding material, a method for producing the molded body, and a housing for electric and electronic equipment composed of the molded body.

The present inventors paid attention to the molecular structure of cellulose, made cellulose a cellulose derivative having a specific structure having an ether structure and an ester structure, and a molding material containing the cellulose derivative having the specific structure and a polystyrene resin, The inventors have found that a molding material and a molded body excellent in impact resistance and dimensional stability can be provided without lowering the performance such as rigidity, bending strength, heat distortion temperature, and molding processability, and the present invention has been completed. It was.
That is, the said subject can be achieved by the following means.

[1]
The hydrogen atom of the hydroxyl group contained in cellulose
A cellulose derivative comprising at least one group substituted in A) below and at least one group substituted in B) below;
Molding material containing polystyrene resin.
A) Hydrocarbon group: —R _A
B) Acyl group: —CO—R _B (R _B represents a hydrocarbon group.)
[2]
The molding material according to [1], wherein the cellulose derivative further contains at least one group in which a hydrogen atom of a hydroxyl group contained in cellulose is substituted by the following C).
C) a group containing an alkyleneoxy group: —R _C2 —O— and an acyl group: —CO—R _C1 (R _C1 represents a hydrocarbon group, and R _C2 represents an alkylene group having 2 to 4 carbon atoms. )
[3]
[Claim 2] The molding material according to [2], wherein the group containing C) an alkyleneoxy group and an acyl group is a group containing a structure represented by the following general formula (3).

(Wherein R _C1 represents a hydrocarbon group, and R _C2 represents an alkylene group having 2 to 4 carbon atoms.
n represents an integer of 1 or more. )
[4]
The molding material according to any one of [1] to [3], wherein R _A is an alkyl group having 1 to 4 carbon atoms.
[5]
The molding material according to any one of [1] to [4], wherein R _A is a methyl group or an ethyl group.
[6]
The molding material according to any one of [2] to [5], wherein R _B and R _C1 are each independently an alkyl group or an aryl group.
[7]
The molding material according to any one of [2] to [6], wherein R _B and R _C1 are each independently a methyl group, an ethyl group, or a propyl group.
[8]
The molding material according to any one of [1] to [6], wherein R _B is a hydrocarbon group having a branched structure having 3 to 10 carbon atoms.
[9]
The molding material according to any one of [2] to [8], wherein the alkyleneoxy group is a group represented by the following formula (1) or (2).

[10]
The molding material according to any one of [1] to [9], wherein the cellulose derivative is substantially free of carboxyl groups, sulfonic acid groups, and salts thereof.
[11]
The molding material according to any one of [1] to [10], wherein the cellulose derivative is insoluble in water.
[12]
The molding material according to any one of [1] to [11], wherein the polystyrene-based resin is polystyrene or high-impact polystyrene (HIPS).
[13]
The molding material according to any one of [1] to [12], further comprising a compatibilizer.
[14]
The molding material according to [13], wherein the compatibilizing agent has a polystyrene unit.
[15]
[1] A molded product obtained by thermoforming the molding material according to any one of [14].
[16]
[1] A method for producing a molded body, comprising a step of heating and molding the molding material according to any one of [14].
[17]
[15] A casing for an electric and electronic device comprising the molded article according to [15].

Since the molding material of the present invention has excellent thermoplasticity, it can be molded by heat molding or the like. In addition, the molding material and the molded body of the present invention are excellent in performance such as rigidity, bending strength, heat resistance and molding processability, and have good impact resistance and dimensional stability. It can be suitably used as a component part such as an electric / electronic device, a machine part, a house / building material, and the like. Moreover, since the molding material of this invention uses the cellulose derivative obtained from the cellulose which is plant-derived resin, it can substitute for the conventional petroleum-derived resin as a raw material which can contribute to global warming prevention.

In the present invention, the hydrogen atom of the hydroxyl group contained in cellulose is
A cellulose derivative (hereinafter also referred to as “cellulose derivative”) comprising at least one group substituted with A) below and at least one group substituted with B) below;
The present invention relates to a molding material containing a polystyrene resin.
A) Hydrocarbon group: —R _A
B) Acyl group: —CO—R _B (R _B represents a hydrocarbon group.)
Hereinafter, the present invention will be described in detail.

1. Cellulose derivative The cellulose derivative contained in the molding material of the present invention has a hydrogen atom of a hydroxyl group contained in cellulose.
A cellulose derivative comprising at least one group substituted with A) below and at least one group substituted with B) below.
A) Hydrocarbon group: —R _A
B) Acyl group: —CO—R _B (R _B represents a hydrocarbon group.)
That is, the cellulose derivative in the present invention is a cellulose ether ester, and 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: —R _A , B) Substituted by an acyl group: —CO—R _B (R _B represents a hydrocarbon group).
More specifically, the cellulose derivative in the present invention has a repeating unit represented by the following general formula (A).

In the general formula (A), R ² , R ³ and R ⁶ are each independently a hydrogen atom, A) hydrocarbon group: —R _A , B) acyl group: —CO—R _B (R _B is carbon Represents a hydrogen group) or other substituents. However, at least a part of R ² , R ³ , and R ⁶ represents A) a hydrocarbon group, and at least a part of R ² , R ³ , and R ⁶ represents B) an acyl group.

As described above, the cellulose derivative in the present invention has thermoplasticity because at least part of the hydroxyl group of the β-glucose ring is etherified and esterified with A) a hydrocarbon group and B) an acyl group. It can be expressed and is suitable for molding.
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 only needs to contain the A) hydrocarbon group and B) acyl group in any part of the whole, and may be composed of the same repeating unit, or a plurality of types. It may consist of repeating units. The cellulose derivative does not need to contain all of the A) hydrocarbon group and B) acyl group in one repeating unit.
More specific embodiments include the following embodiments, for example.
(1) At least one of R ² , R ³ and R ⁶ is A) a repeating unit substituted with a hydrocarbon group, and at least one of R ² , R ³ and R ⁶ is substituted with B) an acyl group A cellulose derivative composed of repeating units.
(2) At least one of R ² , R ³ and R ⁶ of one repeating unit is substituted with A) a hydrocarbon group, and at least one of the other is substituted with B) an acyl group ( That is, a cellulose derivative composed of the same type of repeating units having the substituents A) and B) 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.
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 (A)).
Moreover, the cellulose derivative may have other substituents other than a hydrogen atom, A) a hydrocarbon group, and B) an acyl group.

A) Hydrocarbon group: —R _A may be an aliphatic group or an aromatic group.
When R _A is 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.
When R _A is an aromatic group, it may be either a single ring or a condensed ring. In the case where R _A is an aromatic group, the preferred carbon number is 6 to 18, more preferably 6 to 14, and still more preferably 6 to 10. Examples of the aromatic group include a phenyl group, a naphthyl group, a phenanthryl group, and an anthryl group.
A) The hydrocarbon group is preferably an aliphatic group because the resulting molding material (hereinafter sometimes referred to as “cellulose resin composition” or “resin composition”) has excellent impact resistance. From the viewpoint of excellent moldability such as melt flow rate, an alkyl group is more preferable, and an alkyl group having 1 to 4 carbon atoms (lower alkyl group) is more preferable. Specific examples include 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. A group or an ethyl group is particularly preferred.

B) Acyl group: In —CO—R _B , R _B represents a hydrocarbon group. R _B is an aliphatic group, and may be any aromatic group.
If R _B is an aliphatic group, straight chain, branched, and may be any of circular, it may have an unsaturated bond. Examples of the aliphatic group include an alkyl group, a cycloalkyl group, an alkenyl group, and an alkynyl group.
If R _B is an aromatic group may be either monocyclic and condensed. Examples of the aromatic group include a phenyl group, a naphthyl group, a phenanthryl group, and an anthryl group.
R _B is preferably an alkyl group or an aryl group. R _B is more preferably an alkyl group having 1 to 12 carbon atoms or an aryl group, still more preferably an alkyl group having 1 to 12 carbon atoms, and particularly preferably an alkyl group having 1 to 4 carbon atoms (preferably a methyl group). Group, ethyl group, propyl group), and most preferably an alkyl group having 1 or 2 carbon atoms (that is, a methyl group or an ethyl group).
Also, R _B, it is also preferably a hydrocarbon group having a branched structure having 3 to 10 carbon atoms, more preferably an alkyl group having a branched structure having 3 to 10 carbon atoms, having 7-9 carbon atoms More preferably, it is an alkyl group having a branched structure.
The R _B, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group, a heptyl group, 3-heptyl, 2-ethylhexyl group, tert- butyl Group, isoheptyl group, and the like. Preferably, R _B is a methyl group, an ethyl group, a propyl group, a 3-heptyl group, or a 2-ethylhexyl group, and more preferably a methyl group, an ethyl group, a 3-heptyl group, or a 2-ethylhexyl group.

The cellulose derivative in the molding material of the present invention is a cellulose derivative in which the hydrogen atom of the hydroxyl group contained in cellulose contains at least one group substituted with A) and at least one group substituted with B). However, it is preferable from the viewpoint of impact resistance that it further contains at least one group in which the hydrogen atom of the hydroxyl group contained in cellulose is substituted by the following C).
C) a group containing an alkyleneoxy group: —R _C2 —O— and an acyl group: —CO—R _C1 (R _C1 represents a hydrocarbon group, and R _C2 represents an alkylene group having 2 to 4 carbon atoms. )

In the acyl group (—CO—R _C1 ) contained in C), R _C1 represents a hydrocarbon group. As the hydrocarbon group represented by R _{C1, the same} groups as those described above for R _B can be applied. The preferred range of R _C1 is the same as R _B.

In the alkyleneoxy group (—R _C2 —O—) contained in C), R _C2 represents an alkylene group having 2 to 4 carbon atoms. R _C2 may be linear, branched or cyclic, but is preferably linear or branched, and more preferably branched.
The alkyleneoxy group (—R _C2 —O—) is preferably an alkyleneoxy group having 2 or 3 carbon atoms. Specific examples of the alkyleneoxy group preferably include the following structures.

Among them, a group represented by the following formula (1) or (2) in which —R _C2 —O— is branched is preferable because the obtained resin composition has excellent bending elastic modulus.

The group of C) may contain a plurality of alkyleneoxy groups or may contain only one. Preferably, the group of C) can be represented by the following general formula (3).

In the general formula (3), R _C1 represents a hydrocarbon group, and R _C2 represents an alkylene group having 2 to 4 carbon atoms. The preferred ranges of R _C1 and R _C2 are the same as those described above. n is an integer of 1 or more. 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. n is preferably 1 to 5, more preferably 1 to 3, and still more preferably 1. When a plurality of R _C2 are present, they may be the same or different, but are preferably the same.
In addition, the cellulose derivative in the present invention is a group of C) containing only one alkyleneoxy group (a group in which n is 1 in the general formula (3)) and C) containing two or more alkyleneoxy groups. And a group (a group in which n is 2 or more in the above general formula (3)).

Further, the bonding direction of the alkyleneoxy group to the cellulose derivative in the group C) is not particularly limited, but it is preferable that the alkylene group part (R _C2 ) of the alkyleneoxy group is bonded to the β-glucose ring structure side.

R _A in A), R B in _B ), R _C1 and R _C2 in C) may have a further substituent or may be unsubstituted, but are preferably unsubstituted.

_{R A} in the A), _{R B} in the B), in the case where the _{where R C1} and _{R C2} in the C) has a further substituent, examples of the further substituent include a halogen atom (e.g. fluorine atom, chlorine atom, bromine Atoms, iodine atoms), hydroxy groups, alkoxy groups (the alkyl group preferably has 1 to 5 carbon atoms), alkenyl groups, and the like. However, even when a substituent is included, R _C2 has 2 or 3 carbon atoms. Note that when R _A , R _B , and R _C1 are other than an alkyl group, they may have an alkyl group (preferably having a carbon number of 1 to 5) as a substituent.

In particular, when R _B and R _C1 have a further substituent, it is preferable that they substantially have no carboxyl group, sulfonic acid group, and salts thereof. When the cellulose derivative is substantially free of carboxyl groups, sulfonic acid groups, and salts thereof, the molding material of the present invention can be made water-insoluble and the moldability can be further improved. In addition, when the cellulose derivative has a carboxyl group, a sulfonic acid group, and a salt thereof, it is known that the compound stability is deteriorated, and in particular, thermal decomposition may be promoted. It is preferable.
Note that “substantially free of carboxyl groups, sulfonic acid groups, and salts thereof” means only when the cellulose derivative in the present invention has no carboxyl groups, sulfonic acid groups, and salts thereof. In addition, the case where the cellulose derivative in the present invention has a trace amount of carboxyl groups, sulfonic acid groups, and salts thereof in a range insoluble in water is included. For example, the cellulose as a raw material may contain a carboxyl group, and the cellulose derivative using the above-described substituents A) to C) introduced therein may contain a carboxyl group. , A sulfonic acid group, and a cellulose derivative substantially free of salts thereof.
In this case, the preferred content of the carboxyl group, sulfonic acid group, and salts thereof is 1% by mass or less, more preferably 0.5% by mass or less, based on the cellulose derivative.

In addition, the cellulose derivative in the present invention is preferably insoluble in water. Here, “being insoluble in water” means that the solubility in 100 parts by mass of water at 25 ° C. is 5 parts by mass or less.

Specific examples of the cellulose derivative in the present invention include acetyl methyl cellulose, acetyl ethyl cellulose, acetyl propyl cellulose, acetyl butyl cellulose, acetyl pentyl cellulose, acetyl hexyl cellulose, acetyl cyclohexyl cellulose, acetyl phenyl cellulose, acetyl naphthyl cellulose, propionyl methyl cellulose, and propionyl ethyl cellulose. , Propionylpropylcellulose, propionylbutylcellulose, propionylpentylcellulose, propionylhexylcellulose, propionylcyclohexylcellulose, propionylphenylcellulose, propionylnaphthylcellulose, butyrylmethylcellulose, butyrylethylcellulose, butyrylpropylcellulose , Butyrylbutylcellulose, butyrylpentylcellulose, butyrylhexylcellulose, butyrylcyclohexylcellulose, butyrylphenylcellulose, butyrylnaphthylcellulose, methylcellulose-2-ethylhexanoate, ethylcellulose-2-ethylhexanoate, propylcellulose -2-ethylhexanoate, butylcellulose-2-ethylhexanoate, pentylcellulose-2-ethylhexanoate, hexylcellulose-2-ethylhexanoate, cyclohexylcellulose-2-ethylhexanoate, phenylcellulose -2-ethylhexanoate, naphthylcellulose-2-ethylhexanoate, acetoxyethylmethylacetylcellulose, acetoxyethylethylacetyl cell Acetoxyethylpropylacetylcellulose, acetoxyethylbutylacetylcellulose, acetoxyethylpentylacetylcellulose, acetoxyethylhexylacetylcellulose, acetoxyethylcyclohexylacetylcellulose, acetoxyethylphenylacetylcellulose, acetoxyethylnaphthylacetylcellulose, acetoxyethylmethylpropionylcellulose, Acetoxyethyl ethyl propionyl cellulose, Acetoxy ethyl propyl propionyl cellulose, Acetoxy ethyl butyl propionyl cellulose, Acetoxy ethyl pentyl propionyl cellulose, Acetoxy ethyl hexyl propionyl cellulose, Acetoxy ethyl cyclohexyl propionyl cellulose, Acetoxy Tylphenylpropionylcellulose, acetoxyethylnaphthylpropionylcellulose, acetoxyethylmethylcellulose-2-ethylhexanoate, acetoxyethylethylcellulose-2-ethylhexanoate, acetoxyethylpropylcellulose-2-ethylhexanoate, acetoxyethylbutylcellulose 2-ethylhexanoate, acetoxyethylpentylcellulose-2-ethylhexanoate, acetoxyethylhexylcellulose-2-ethylhexanoate, acetoxyethylcyclohexylcellulose-2-ethylhexanoate, acetoxyethylphenylcellulose-2-ethyl Hexanoate, acetoxyethyl naphthylcellulose-2-ethylhexanoate, propionyloxyethyl Acetylacetylcellulose, propionyloxyethylethylacetylcellulose, propionyloxyethylpropylacetylcellulose, propionyloxyethylbutylacetylcellulose, propionyloxyethylpentylacetylcellulose, propionyloxyethylhexylacetylcellulose, propionyloxyethylcyclohexylacetylcellulose, propionyloxyethylphenylacetyl Cellulose, propionyloxyethyl naphthylacetyl cellulose, propionyloxyethylmethylpropionylcellulose, propionyloxyethylethylpropionylcellulose, propionyloxyethylpropylpropionylcellulose, propionyloxyethylbutylpropionylcellulose, pro Onyloxyethylpentylpropionylcellulose, propionyloxyethylhexylpropionylcellulose, propionyloxyethylcyclohexylpropionylcellulose, propionyloxyethylphenylpropionylcellulose, propionyloxyethylnaphthylpropionylcellulose, propionyloxyethylmethylcellulose-2-ethylhexanoate, propionyloxyethyl Ethylcellulose-2-ethylhexanoate, propionyloxyethylpropylcellulose-2-ethylhexanoate, propionyloxyethylbutylcellulose-2-ethylhexanoate, propionyloxyethylpentylcellulose-2-ethylhexanoate, propionyloxy Ethyl hexyl cellulose -2-ethylhexanoate, propionyloxyethylcyclohexyl cellulose-2-ethylhexanoate, propionyloxyethylphenylcellulose-2-ethylhexanoate, propionyloxyethylnaphthylcellulose-2-ethylhexanoate, acetoxypropylmethyl Acetylcellulose, acetoxypropylethylacetylcellulose, acetoxypropylpropylacetylcellulose, acetoxypropylbutylacetylcellulose, acetoxypropylpentylacetylcellulose, acetoxypropylhexylacetylcellulose, acetoxypropylcyclohexylacetylcellulose, acetoxypropylphenylacetylcellulose, acetoxypropylnaphthylacetylcellulose , Propio Luoxypropylmethylacetylcellulose, propionyloxypropylethylacetylcellulose, propionyloxypropylpropylacetylcellulose, propionyloxypropylbutylacetylcellulose, propionyloxypropylpentylacetylcellulose, propionyloxypropylhexylacetylcellulose, propionyloxypropylcyclohexylacetylcellulose, propionyl Examples thereof include oxypropylphenylacetylcellulose, propionyloxypropylnaphthylacetylcellulose, valeroxypropylmethylvaleroylcellulose, valeroxybutylmethylvaleroylcellulose, and the like.

The molding material of the present invention may contain only one kind of the specific cellulose derivative or two or more kinds.

In the cellulose derivative of the present invention, A) hydrocarbon group: —R _A , B) acyl group: —CO—R _B , and C) alkyleneoxy group: —R _C2 —O— and acyl group: —CO—R _C1 And the number of substitution groups per each β-glucose ring unit (substitution degree) are not particularly limited.

For example, A) hydrocarbon group: the degree of substitution DS _{A of} —R _A (the number of _RA for the hydroxyl groups at the 2nd, 3rd and 6th positions of the β-glucose ring in the repeating unit) is 1.0 <DS _A It is preferable that 1.0 <DS _A <2.5. Further, DS _A is preferably 1.1 or more.
B) Degree of substitution DS _{B of} acyl group (—CO—R _B ) (the number of —CO—R _B with respect to hydroxyl groups at the 2nd, 3rd and 6th positions of the cellulose structure of the β-glucose ring in the repeating unit) 0.1 <DS _B is preferable, and 0.1 <DS _B <2.0 is more preferable.
C) Degree of substitution DS _C of a group containing an alkyleneoxy group: —R _C2 —O— and an acyl group: —CO—R _C1 (in the repeating unit, the 2nd, 3rd and 6th positions of the cellulose structure of the β-glucose ring) position of C to the hydroxyl group) alkyleneoxy _{group: -R} C2 -O- acyl group: the number of groups containing a _{-CO-R C1)} is preferably _{_{0 <DS C, 0 <DS}} C <1 0.0 is more preferable. 0 <By a DS _C, it is possible to lower the melting initiation temperature of the cellulose derivative can be performed thermoforming easier.
By setting the degree of substitution within the above range, mechanical strength, moldability, and the like can be improved.

Further, the number of unsubstituted hydroxyl groups present in the cellulose derivative is not particularly limited. The degree of substitution DS _{H of} hydrogen atoms (ratio in which the hydroxyl groups at the 2nd, 3rd and 6th positions in the repeating unit are unsubstituted) can be in the range of 0 to 1.5, preferably 0 to 0.6. And it is sufficient. By the DS _H and 0.6 or less, or to improve the fluidity of the molding material, the foaming and the like due to water absorption of the molding material during acceleration and molding of the pyrolysis can or is suppressed.

In addition, the cellulose derivative in the present invention may have a substituent other than A) a hydrocarbon group, B) an acyl group, and C) a group containing an alkyleneoxy group and an acyl group. Examples of the substituent that may be included include a hydroxyethyl group, a hydroxypropyl group, a hydroxyethoxyethyl group, a hydroxypropoxypropyl group, a hydroxyethoxyethoxyethyl group, and a hydroxypropoxypropoxypropyl group. Therefore, the sum of the degree of substitution of all the substituents of the cellulose derivative is 3, but (DS _A + DS _B + DS _C + DS _H ) is 3 or less.

The amount of alkyleneoxy group introduced in the group C) is expressed in terms of molar substitution (MS: number of moles of substituent introduced per glucose residue) (edited by Cellulose Society, Cellulose Dictionary P142). The molar substitution degree MS of the alkyleneoxy group is preferably 0 <MS, more preferably 0 <MS ≦ 1.5, and still more preferably 0 <MS <1.0. When MS is 1.5 or less (MS ≦ 1.5), heat resistance, moldability and the like can be improved, and a cellulose derivative suitable for a molding material can be obtained.

The cellulose derivative in the molding material of the present invention is a cellulose derivative in which the hydrogen atom of the hydroxyl group contained in cellulose contains at least one group substituted with A) and at least one group substituted with B). However, when a hydrogen atom of a hydroxyl group contained in cellulose is substituted, from the viewpoint of moldability, it is substituted only by A) and B) or A), B), and C. ) Is preferred. That is, in the cellulose derivative in the present invention, it is preferable that the hydrogen atom of the hydroxyl group contained in the cellulose is not substituted with a group other than the above A), B), and C).

The molecular weight of the cellulose derivative in the present invention is preferably such that the number average molecular weight (Mn) is in the range of 5 × 10 ³ to 1000 × 10 ³ , more preferably in the range of 10 × 10 ³ to 500 × 10 ³ , and 10 × 10 ³ to A range of 200 × 10 ³ is most preferred. The mass average molecular weight (Mw) is preferably in the range of 7 × 10 ³ to 10000 × 10 ³ , more preferably in the range of 15 × 10 ³ to 5000 × 10 ³ , and in the range of 100 × 10 ³ to 3000 × 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 1.5 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), mass average molecular weight (Mw) and molecular weight distribution (MWD) can be measured using gel permeation chromatography (GPC). Specifically, N-methylpyrrolidone is used as a solvent, a polystyrene gel is used, and the molecular weight can be determined using a conversion molecular weight calibration curve obtained in advance from a standard monodisperse polystyrene constituent curve.

2. Method for Producing Cellulose Derivative The method for producing a cellulose derivative in the present invention is not particularly limited, and the cellulose derivative in the present invention can be produced by using cellulose as a raw material and etherifying and esterifying cellulose. The raw material for cellulose is not limited, and examples thereof include cotton, linter, and pulp.

A preferred embodiment of a method for producing a cellulose derivative having the above A) hydrocarbon group: —R _A and B) acyl group: —CO—R _B (R _B represents a hydrocarbon group) includes cellulose ether, base It includes a step of esterification by reacting acid chloride or acid anhydride in the presence.
As the cellulose ether, for example, those in which at least a part of the hydrogen atoms of the hydroxyl groups at the 2nd, 3rd and 6th positions of the β-glucose ring contained in cellulose are substituted with hydrocarbon groups can be used. Specific examples include methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, allyl cellulose, and benzyl cellulose.

A) hydrocarbon group: —R _A , B) acyl group: —CO—R _B (R _B represents a hydrocarbon group), and C) alkyleneoxy group: —R _C2 —O— and an acyl group: A preferred embodiment of a method for producing a cellulose derivative having a group containing —CO—R _C1 (R _C1 represents a hydrocarbon group and R _C2 represents an alkylene group having 2 to 4 carbon atoms) is a hydrocarbon group. And hydroxyethyl cellulose ether having a hydroxyethyl group or hydroxypropyl cellulose ether having a hydroxypropyl group are reacted by an acid chloride or an acid anhydride to react with the esterification (acylation). is there.
Further, as another embodiment, for example, after etherification with cellulose ether such as methyl cellulose or ethyl cellulose with propylene oxide or the like, alkyl chloride such as methyl chloride or ethyl chloride / alkylene oxide having 3 carbon atoms or the like is allowed to act on cellulose. Furthermore, a method including a step of esterification by reacting an acid chloride or an acid anhydride is also included.
As a method for reacting acid chloride, for example, the method described in Cellulose 10; 283-296, 2003 can be used.
Specific examples of the cellulose ether having a hydrocarbon group and a hydroxyethyl group include hydroxyethyl methyl cellulose, hydroxyethyl ethyl cellulose, hydroxyethyl propyl cellulose, hydroxyethyl allyl cellulose, and hydroxyethyl benzyl cellulose. Preferred are hydroxyethyl methyl cellulose and hydroxyethyl ethyl cellulose.
Specific examples of the cellulose ether having a hydrocarbon group and a hydroxypropyl group include hydroxypropylmethylcellulose, hydroxypropylethylcellulose, hydroxypropylpropylcellulose, hydroxypropylallylcellulose, hydroxypropylbenzylcellulose, and the like. Preferred are hydroxypropylmethylcellulose and hydroxypropylethylcellulose.

As the acid chloride, B) acyl group and carboxylic acid chloride corresponding to the acyl group contained in C) can be used. Examples of the carboxylic acid chloride include acetyl chloride, propionyl chloride, butyryl chloride, isobutyryl chloride, pentanoyl chloride, 2-methylbutanoyl chloride, 3-methylbutanoyl chloride, pivaloyl chloride, hexanoyl chloride, 2-methylpentanoyl chloride, 3-methylpentanoyl chloride, 4-methylpentanoyl chloride, 2,2-dimethylbutanoyl chloride, 2,3-dimethylbutanoyl chloride, 3,3-dimethylbutanoyl chloride, 2- Ethylbutanoyl chloride, heptanoyl chloride, 2-methylhexanoyl chloride, 3-methylhexanoyl chloride, 4-methylhexanoyl chloride, 5-methylhexanoyl chloride, 2,2-dimethylpentanoyl chloride, , 3-dimethylpentanoyl chloride, 3,3-dimethylpentanoyl chloride, 2-ethylpentanoyl chloride, cyclohexanoyl chloride, octanoyl chloride, 2-methylheptanoyl chloride, 3-methylheptanoyl chloride, 4-methyl Heptanoyl chloride, 5-methylheptanoyl chloride, 6-methylheptanoyl chloride, 2,2-dimethylhexanoyl chloride, 2,3-dimethylhexanoyl chloride, 3,3-dimethylhexanoyl chloride, 2-ethylhexanoyl Chloride, 2-propylpentanoyl chloride, nonanoyl chloride, 2-methyloctanoyl chloride, 3-methyloctanoyl chloride, 4-methyloctanoyl chloride, 5-methyloctanoyl chloride, 6-methyloctanoy Chloride, 2,2-dimethylheptanoyl chloride, 2,3-dimethylheptanoyl chloride, 3,3-dimethylheptanoyl chloride, 2-ethylheptanoyl chloride, 2-propylhexanoyl chloride, 2-butylpentanoyl chloride, Decanoyl chloride, 2-methylnonanoyl chloride, 3-methylnonanoyl chloride, 4-methylnonanoyl chloride, 5-methylnonanoyl chloride, 6-methylnonanoyl chloride, 7-methylnonanoyl chloride, 2,2- Examples thereof include dimethyloctanoyl chloride, 2,3-dimethyloctanoyl chloride, 3,3-dimethyloctanoyl chloride, 2-ethyloctanoyl chloride, 2-propylheptanoyl chloride, 2-butylhexanoyl chloride and the like.

As the acid anhydride, for example, carboxylic acid anhydrides corresponding to the acyl group contained in the above B) acyl group and C) 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 acid. An anhydride, nonanoic acid anhydride, etc. are mentioned.
As described above, since the cellulose derivative in the present invention preferably has no carboxylic acid as a substituent, for example, a dicarboxylic acid such as phthalic anhydride, maleic anhydride, or the like, and a compound that generates a carboxyl group by reacting with cellulose. It is preferable not to use.

Other specific manufacturing conditions can follow the usual method. For example, the method described in “Encyclopedia of Cellulose” pages 131 to 164 (Asakura Shoten, 2000) can be referred to.

3. Polystyrene resin The molding material of the present invention contains a polystyrene resin.
Since the polystyrene resin has low hygroscopicity and is excellent in dispersibility with respect to the specific cellulose derivative in the present invention, strain due to moisture absorption can be dispersed and the dimensional stability of the molded body can be improved. Moreover, since the polystyrene resin is excellent in fluidity, the moldability of the molding material can be improved. Moreover, by being excellent in dispersibility, performances such as rigidity, bending strength, and heat distortion temperature are not lowered as compared with the case where a specific cellulose derivative is used alone.

The polystyrene resin used for the molding material of the present invention is preferably a polystyrene resin obtained by polymerizing a styrene monomer or impact-resistant polystyrene (HIPS resin), more preferably polystyrene or HIPS resin.

Examples of the styrene monomer used in the polystyrene resin include styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, vinyl xylene, ethyl styrene, dimethyl styrene, p-tert-butyl styrene, vinyl naphthalene. , Styrene derivatives such as methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, tribromostyrene and the like, and styrene is particularly preferable. Furthermore, these can be used alone or in combination of two or more.

The HIPS resin is a mixture of a rubbery polymer in polystyrene. As a mixing method, a simple mechanical blending method may be used, but in order to obtain good compatibility, a styrene monomer is graft-copolymerized in the presence of a rubbery polymer, so-called graft copolymerization. What was obtained by prescription is more preferable. In addition, it is also preferable to use a rubber-modified polystyrene resin (graft polymer) obtained by this method, which is obtained by a so-called graft-blend method in which polystyrene obtained by a separate method is mixed. As the polymerization method, emulsion polymerization, solution polymerization, suspension polymerization and the like can be applied.

Specific examples of the rubbery polymer include conjugated diene rubbers such as polybutadiene, styrene-butadiene copolymer, hydrogenated styrene-butadiene block copolymer, and non-conjugated diene polymers such as ethylene-propylene copolymer. Although rubber is mentioned, polybutadiene is particularly preferable.

The rubber content in the HIPS resin is preferably 1 to 40% by mass, more preferably 3 to 30% by mass.

In the present invention, the mass average molecular weight (Mw) of the polystyrene-based resin is preferably 10,000 to 500,000, and more preferably 50,000 to 200,000.
The measurement of a mass average molecular weight (Mw) can be performed using gel permeation chromatography (GPC). Specifically, N-methylpyrrolidone is used as a solvent, a polystyrene gel is used, and the molecular weight can be determined using a conversion molecular weight calibration curve obtained in advance from a standard monodisperse polystyrene constituent curve.

These polystyrene resins can be used alone or in combination of two or more.

As the polystyrene resin, a commercially available product may be used, and examples thereof include polystyrene: G200C (Toyo Styrene Co., Ltd.), HIPS resin: H450 (Toyo Styrene Co., Ltd.), and the like.

4). Molding Material and Molded Body The molding material of the present invention contains the cellulose derivative described above and a polystyrene resin, and may contain other additives as necessary.
The content rate of the component contained in the molding material of this invention is not specifically limited.
The content ratio of the cellulose derivative contained in the molding material of the present invention is not particularly limited. Preferably, the cellulose derivative is contained in an amount of 30% by mass or more, more preferably 35% by mass or more, further preferably 45% by mass or more and 99% by mass or less, and particularly preferably 60% by mass or more and 95% by mass or less based on the total solid content. .
The content rate of the polystyrene-type resin contained in the molding material of this invention is not specifically limited. Preferably, the polystyrene-based resin is contained in an amount of 1 to 70% by mass, more preferably 1 to 65% by mass, and still more preferably 5 to 50% by mass with respect to the total solid content.
In addition, from the viewpoint of establishing impact resistance, molding processability, and heat resistance, the mass composition ratio of the cellulose derivative and the polystyrene resin (cellulose derivative / polystyrene resin) is 20/80 to 95/5. It is preferably 40/60 to 90/10, and more preferably 60/40 to 90/10.

The molding material of the present invention may contain various additives such as a compatibilizer, an antioxidant, a filler (reinforcing material), a flame retardant, etc., as necessary, in addition to the cellulose derivative and the polystyrene resin. Good.

The molding material of the present invention preferably contains a compatibilizing agent. The compatibilizing agent is used to compatibilize the cellulose derivative and polystyrene resin in the present invention. When a compatibilizing agent is added to the molding material of the present invention, the dispersibility of the polystyrene-based resin with respect to the cellulose derivative in the present invention is further improved, and the properties such as fluidity (molding processability) and impact resistance of the molding material are further improved. improves.

In the present invention, as the compatibilizing agent, a compatibilizing agent having a polystyrene unit is preferable because of its high affinity for the polystyrene phase.
Preferable compatibilizers include block copolymers and graft polymers having polystyrene units.
Specifically, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-isobutylene copolymer, styrene-methyl methacrylate copolymer, styrene-ethylene copolymer, styrene-propylene copolymer, ethylene Examples thereof include glycidyl methacrylate copolymer-graft-styrene polymer, ethyl acrylate / maleic anhydride copolymer-graft-styrene polymer, and ethylene / vinyl acetate copolymer-graft-styrene polymer. These can be synthesized by existing polymerization methods (radical polymerization, anionic polymerization, cationic polymerization) or polymer reactions, or commercially available ones can also be used. As a commercial item, Modiper A1100, A3100, A4100, A5100, A6100 (made by NOF Corporation) etc. are mentioned, for example. In addition, the compatibilizer is not limited to these, and the compatibilizer described in “Plastic compatibilizer development / evaluation / recycling” (CMC Publishing Co., Ltd.) can also be suitably used.

The content of the compatibilizing agent in the molding material of the present invention is preferably 0.1 parts by mass to 30 parts by mass, more preferably 0.5 parts with respect to 100 parts by mass of the total amount of the cellulose derivative and polystyrene resin in the present invention. Parts by mass to 20 parts by mass. By setting it within this range, a sufficient compatibility improvement effect can be obtained, and problems such as an increase in the viscosity of the molding material are unlikely to occur.

When the molding material of the present invention contains an antioxidant, its content is not limited, but it is usually 30% by mass or less, preferably 0.01 to 10% by mass in the molding material. By setting it within this range, the resin can obtain a sufficient stability improving effect against heating in the kneading or molding process, which is preferable.
Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like, and phenol-based antioxidants are preferable. As the phenolic antioxidant, Irganox 1010, Irganox 1076, Irganox 3114 manufactured by Ciba Specialty Chemicals Co., Ltd. can be suitably used.

The molding material of the present invention may contain a filler (reinforcing material). By containing the filler, the mechanical properties of the molded body formed of the molding material can be enhanced.
A well-known thing can be used as a filler. The shape of the filler may be any of fibrous, plate-like, granular, powdery and the like. Further, it may be inorganic or organic.
Specifically, as the inorganic filler, glass fiber, carbon fiber, graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium whisker, silicon whisker, wollastonite, sepiolite, slag fiber, zonolite, Elastadite, gypsum fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber and boron fiber, and other inorganic fillers; glass flakes, non-swellable mica, carbon black, graphite, metal foil , Ceramic beads, talc, clay, mica, sericite, zeolite, bentonite, dolomite, kaolin, fine silicate, feldspar, potassium titanate, shirasu balloon, calcium carbonate, magnesium carbonate, barium sulfate, calcium oxide Beam, aluminum oxide, titanium oxide, magnesium oxide, aluminum silicate, silicon oxide, aluminum hydroxide, magnesium hydroxide, gypsum, novaculite, dawsonite, and a plate-like or granular inorganic fillers of clay or the like.

Organic fillers include synthetic fibers such as polyester fiber, nylon fiber, acrylic fiber, regenerated cellulose fiber, and acetate fiber, and natural fibers such as kenaf, ramie, cotton, jute, hemp, sisal, Manila hemp, flax, linen, silk, and wool. Examples thereof include fibrous organic fillers obtained from microcrystalline cellulose, sugar cane, wood pulp, paper waste, waste paper and the like, and granular organic fillers such as organic pigments.

When the molding material contains a filler, the content is not limited, but is usually 30 parts by mass or less, preferably 5 to 10 parts by mass with respect to 100 parts by mass of the cellulose derivative.

The molding material of the present invention may contain a flame retardant. Thereby, the flame retarding effect such as reduction or suppression of the burning rate can be improved.
The flame retardant is not particularly limited, and a conventional flame retardant can be used. For example, brominated flame retardants, chlorine-based flame retardants, phosphorus-containing flame retardants, silicon-containing flame retardants, nitrogen compound-based flame retardants, inorganic flame retardants and the like can be mentioned. Among these, hydrogen halides are not generated by thermal decomposition during resin compounding or molding, and do not corrode processing machines or molds or deteriorate the working environment. Phosphorus-containing flame retardants and silicon-containing flame retardants are preferred because they are less likely to adversely affect the environment through the generation of harmful substances such as dioxins when they are diffused or decomposed.

The phosphorus-containing flame retardant is not particularly limited, and a commonly used one can be used. Examples thereof include organic phosphorus compounds such as phosphate esters, phosphate condensation esters, and polyphosphates.

Specific examples of phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris (isopropylphenyl) Phosphate, tris (phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, diphenyl (2-ethylhexyl) phosphate, di (isopropylphenyl) phenyl phosphate, monoisodecyl phosphate, 2-acryloyloxyethyl Acid phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl -2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine oxide, tricresylphosphine oxide, diphenyl methanephosphonate, diethyl phenylphosphonate Can be mentioned.

Examples of the phosphoric acid condensed ester include resorcinol polyphenyl phosphate, resorcinol poly (di-2,6-xylyl) phosphate, bisphenol A polycresyl phosphate, hydroquinone poly (2,6-xylyl) phosphate, and condensates thereof. Aromatic phosphoric acid condensed ester and the like.

In addition, polyphosphates composed of salts of phosphoric acid, polyphosphoric acid and metals of Groups 1 to 14 of the periodic table, ammonia, aliphatic amines, and aromatic amines can also be mentioned. As typical salts of polyphosphates, lithium salts, sodium salts, calcium salts, barium salts, iron (II) salts, iron (III) salts, aluminum salts and the like as metal salts, methylamine salts as aliphatic amine salts, Examples include ethylamine salts, diethylamine salts, triethylamine salts, ethylenediamine salts, piperazine salts, and examples of aromatic amine salts include pyridine salts and triazines.

In addition to the above, halogen-containing phosphate esters such as trischloroethyl phosphate, trisdichloropropyl phosphate, tris (β-chloropropyl) phosphate), and structures in which a phosphorus atom and a nitrogen atom are connected by a double bond Phosphazene compounds having phosphoric acid and phosphoric ester amides.
These phosphorus-containing flame retardants may be used singly or in combination of two or more.

Examples of the silicon-containing flame retardant include an organic silicon compound having a two-dimensional or three-dimensional structure, polydimethylsiloxane, or a methyl group at a side chain or a terminal of polydimethylsiloxane, a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, Examples thereof include those substituted or modified with an aromatic hydrocarbon group, so-called silicone oils, or modified silicone oils.

Examples of the substituted or unsubstituted aliphatic hydrocarbon group and aromatic hydrocarbon group include an alkyl group, a cycloalkyl group, a phenyl group, a benzyl group, an amino group, an epoxy group, a polyether group, a carboxyl group, a mercapto group, Examples include a chloroalkyl group, an alkyl higher alcohol ester group, an alcohol group, an aralkyl group, a vinyl group, or a trifluoromethyl group.
These silicon-containing flame retardants may be used alone or in combination of two or more.

Examples of the flame retardant other than the phosphorus-containing flame retardant or the silicon-containing flame retardant include, for example, magnesium hydroxide, aluminum hydroxide, antimony trioxide, antimony pentoxide, sodium antimonate, zinc hydroxystannate, zinc stannate, Metastannic acid, tin oxide, tin oxide salt, zinc sulfate, zinc oxide, ferrous oxide, ferric oxide, stannous oxide, stannic oxide, zinc borate, ammonium borate, ammonium octamolybdate, tungsten Inorganic flame retardants such as acid metal salts, complex oxides of tungsten and metalloid, ammonium sulfamate, ammonium bromide, zirconium compounds, guanidine compounds, fluorine compounds, graphite, and swellable graphite can be used. . These other flame retardants may be used alone or in combination of two or more.

When the molding material of the present invention contains a flame retardant, its content is not limited, but is usually 30 parts by mass or less, preferably 2 to 10 parts by mass with respect to 100 parts by mass of the cellulose derivative. By setting it as this range, impact resistance, brittleness, etc. can be improved, or generation | occurrence | production of pellet blocking can be suppressed.

The molding material of the present invention may contain other components other than those described above for the purpose of further improving various properties such as moldability and flame retardancy within the range not impairing the object of the present invention. .
Examples of the other components include polymers other than the cellulose derivatives and the polystyrene resins, plasticizers, stabilizers (antioxidants, ultraviolet absorbers, etc.), release agents (fatty acids, fatty acid metal salts, oxyfatty acids, Fatty acid ester, aliphatic partially saponified ester, paraffin, low molecular weight polyolefin, fatty acid amide, alkylene bis fatty acid amide, aliphatic ketone, fatty acid lower alcohol ester, fatty acid polyhydric alcohol ester, fatty acid polyglycol ester, modified silicone), antistatic agent , Flame retardant aids, processing aids, anti-drip agents, antibacterial agents, antifungal agents and the like. Further, a coloring agent containing a dye or a pigment can be added.

As the polymer other than the cellulose derivative and the polystyrene resin, any of a thermoplastic polymer and a thermosetting polymer can be used, but a thermoplastic polymer is preferable from the viewpoint of moldability. Specific examples of polymers other than cellulose derivatives include low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-nonconjugated diene copolymer, ethylene-butene- 1 copolymer, polypropylene homopolymer, polypropylene copolymer (such as ethylene-propylene block copolymer), polyolefins such as polybutene-1 and poly-4-methylpentene-1, polybutylene terephthalate, polyethylene terephthalate and other aromatic polyesters, etc. Polyester, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 6T, nylon 12 and other polyamides, polyacetals (including homopolymers and copolymers), Polyurethane, aromatic and aliphatic polyketone, polyphenylene sulfide, polyether ether ketone, thermoplastic starch resin, acrylic resin such as polymethyl methacrylate and methacrylate ester-acrylate ester copolymer, AS resin (acrylonitrile-styrene copolymer) Coalescence), ABS resin, AES resin (ethylene rubber reinforced AS resin), ACS resin (chlorinated polyethylene reinforced AS resin), ASA resin (acrylic rubber reinforced AS resin), polyvinyl chloride, polyvinylidene chloride, vinyl ester Resin, maleic anhydride-styrene copolymer, MS resin (methyl methacrylate-styrene copolymer), polycarbonate, polyarylate, polysulfone, polyethersulfone, phenoxy resin, polyphenylene ether, modified polyphenyle Thermoplastic polyimides such as ether and polyetherimide, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polychloro Fluoropolymers such as trifluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, cellulose acetate, polyvinyl alcohol, unsaturated polyester, melamine resin, phenol resin, urea resin, polyimide, etc. Can be mentioned.
Various acrylic rubbers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers and alkali metal salts thereof (so-called ionomers), ethylene-acrylic acid alkyl ester copolymers (for example, ethylene-ethyl acrylate copolymer) Copolymer, ethylene-butyl acrylate copolymer), diene rubber (for example, 1,4-polybutadiene, 1,2-polybutadiene, polyisoprene, polychloroprene), copolymer of diene and vinyl monomer (for example, Styrene-butadiene random copolymer, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene random copolymer, styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer Polymer, polybutadiene Styrene-grafted styrene, butadiene-acrylonitrile copolymer), polyisobutylene, copolymer of isobutylene and butadiene or isoprene, butyl rubber, natural rubber, thiocol rubber, polysulfide rubber, acrylic rubber, nitrile rubber, poly Examples include ether rubber, epichlorohydrin rubber, fluoro rubber, silicone rubber, and other thermoplastic elastomers such as polyurethane, polyester, and polyamide.

Furthermore, those having various degrees of crosslinking, those having various microstructures such as cis structure and trans structure, those having vinyl groups, those having various average particle diameters, core layers and the like A multi-layer structure polymer called a so-called core-shell rubber, which is composed of one or more shell layers to be covered and whose adjacent layers are composed of different types of polymers, can also be used, and further a core-shell rubber containing a silicone compound Can also be used.
These polymers may be used alone or in combination of two or more.

When the molding material of the present invention contains a polymer other than the cellulose derivative and the polystyrene resin, the content thereof is preferably 30 parts by mass or less, more preferably 2 to 10 parts by mass with respect to 100 parts by mass of the cellulose derivative.

The molding material of the present invention may contain a plasticizer. Thereby, a flame retardance and a moldability can be improved further. As the plasticizer, those commonly used for polymer molding can be used. Examples thereof include polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, polyalkylene glycol plasticizers, and epoxy plasticizers.

Specific examples of the polyester plasticizer include acid components such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, rosin, propylene glycol, 1,3-butanediol, 1,4 -Polyesters composed of diol components such as butanediol, 1,6-hexanediol, ethylene glycol and diethylene glycol, and polyesters composed of hydroxycarboxylic acids such as polycaprolactone. These polyesters may be end-capped with a monofunctional carboxylic acid or monofunctional alcohol, or may be end-capped with an epoxy compound or the like.

Specific examples of the glycerin plasticizer include glycerin monoacetomonolaurate, glycerin diacetomonolaurate, glycerin monoacetomonostearate, glycerin diacetomonooleate, and glycerin monoacetomonomontanate.

Specific examples of polycarboxylic acid plasticizers include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, and trimellitic acid. Trimellitic acid esters such as tributyl, trioctyl trimellitic acid, trihexyl trimellitic acid, diisodecyl adipate, n-octyl-n-decyl adipate, methyl diglycol butyl diglycol adipate, benzyl methyl diglycol adipate, adipic acid Adipic acid esters such as benzylbutyl diglycol, citrate esters such as triethyl acetylcitrate and tributyl acetylcitrate, azelaic acid esters such as di-2-ethylhexyl azelate, sebashi Dibutyl, and include di-2-ethylhexyl sebacate and the like.

Specific examples of the polyalkylene glycol plasticizer include polyethylene glycol, polypropylene glycol, poly (ethylene oxide / propylene oxide) block and / or random copolymer, polytetramethylene glycol, ethylene oxide addition polymer of bisphenols, and bisphenols. And a polyalkylene glycol such as a propylene oxide addition polymer, a tetrahydrofuran addition polymer of bisphenol, or a terminal epoxy-modified compound thereof, a terminal ester-modified compound, a terminal ether-modified compound, and the like.

The epoxy plasticizer generally refers to an epoxy triglyceride composed of an alkyl epoxy stearate and soybean oil, but there are also so-called epoxy resins mainly made of bisphenol A and epichlorohydrin. Can be used.

Specific examples of other plasticizers include benzoate esters of aliphatic polyols such as neopentyl glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyrate, fatty acid amides such as stearamide, oleic acid Examples thereof include aliphatic carboxylic acid esters such as butyl, oxy acid esters such as methyl acetylricinoleate and butyl acetylricinoleate, pentaerythritol, and various sorbitols.

When the molding material of the present invention contains a plasticizer, the content thereof is usually 30 parts by mass or less, preferably 0.005 to 20 parts by mass with respect to 100 parts by mass in total of the cellulose derivative and the polystyrene resin, More preferably, it is 0.01 to 10 parts by mass.

The molded body of the present invention can be obtained by molding a molding material containing the cellulose derivative and the polystyrene resin. More specifically, the cellulose derivative or the cellulose derivative and, if necessary, a molding material containing various additives and the like are heated and obtained by a production method including a step of molding by various molding methods.
The method for producing a molded body of the present invention includes a step of heating and molding the molding material.
Examples of the molding method include injection molding, extrusion molding, blow molding and the like.
The heating temperature is usually 160 to 300 ° C, preferably 180 to 260 ° C.

The use of the molded article of the present invention is not particularly limited. For example, interior or exterior parts of electric and electronic equipment (home appliances, OA / media related equipment, optical equipment, communication equipment, etc.), automobiles, mechanical parts And materials for housing and construction. Among these, from the viewpoint of having excellent heat resistance and impact resistance and low environmental load, for example, exterior parts for electric and electronic devices such as copiers, printers, personal computers, televisions (especially casings) ) Can be suitably used.

Hereinafter, the present invention will be specifically described 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 acetoxypropylmethylacetylcellulose (C-1)>
In a 5 L three-necked flask equipped with a mechanical stirrer, thermometer, condenser, and dropping funnel, weigh 60 g of hydroxypropyl methylcellulose (trade name Metroze 90SH-100; manufactured by Shin-Etsu Chemical) and 2100 mL of N, N-dimethylacetamide and stir at room temperature. did. After confirming that the reaction system became transparent and completely dissolved, 101 mL of acetyl chloride was slowly added dropwise to raise the temperature of the system to 80 ° C. to 90 ° C. After stirring for 3 hours, the temperature of the reaction system was cooled to room temperature. When the reaction solution was added to 10 L of water with vigorous stirring, a white solid was precipitated. The white solid was filtered off by suction filtration and washed with a large amount of water three times. The obtained white solid was vacuum-dried at 100 ° C. for 6 hours to obtain the objective cellulose derivative (C-1) (acetoxypropylmethylacetylcellulose) as a white powder. The solubility of this cellulose derivative (C-1) in water at 25 ° C. was less than 0.1% by mass (insoluble).

<Synthesis Examples 2, 3, and 4: Synthesis of acetoxyethyl methyl acetyl cellulose (C-2), methyl acetyl cellulose (C-3), and ethyl acetyl cellulose (C-4)>
Hydroxypropyl methylcellulose (trade name Metrolose 90SH-100: manufactured by Shin-Etsu Chemical Co., Ltd.) in Synthesis Example 1 was replaced by hydroxyethyl methylcellulose (trade name Marporose ME-250T: manufactured by Matsumoto Yushi), methylcellulose (trade name Marporose M-4000: manufactured by Matsumoto Yushi Co., Ltd.) And acetoxyethyl methyl acetyl cellulose (C-2), methyl acetyl cellulose (C-3), ethyl acetyl cellulose (C-3) in the same manner as in Synthesis Example 1 except that it was changed to ethyl cellulose (trade name Etcel 300CP: manufactured by Dow Chemical). C-4) was obtained. The solubility of these cellulose derivatives (C-2), (C-3), and (C-4) in water at 25 ° C. was less than 0.1% by mass (insoluble).

<Synthesis Example 5: Synthesis of methylcellulose-2-ethylhexanoate (C-5)>
In a 3 L three-necked flask equipped with a mechanical stirrer, thermometer, condenser, and dropping funnel, 80 g of methylcellulose (manufactured by Wako Pure Chemical Industries, Ltd .: methyl substitution degree 1.8) and 1500 mL of pyridine were weighed and stirred at room temperature. Under water cooling, 173 mL of 2-ethylhexanoyl chloride was slowly added dropwise thereto, and the mixture was further stirred at 60 ° C. for 6 hours. After the reaction, the reaction solution was returned to room temperature and quenched by adding 200 mL of methanol under ice cooling. When the reaction solution was added to 12 L of water with vigorous stirring, a white solid was precipitated. The white solid was filtered off by suction filtration and washed 3 times with a large amount of methanol solvent. The resulting white solid was vacuum-dried at 100 ° C. for 6 hours to obtain methylcellulose-2-ethylhexanoate (C-5). The solubility of this cellulose derivative (C-5) in water at 25 ° C. was less than 0.1% by mass (insoluble).

<Synthesis Example 6: Synthesis of valeroxypropyl methyl valeroyl cellulose (C-6)>
Instead of methyl cellulose in Synthesis Example 5 (manufactured by Wako Pure Chemical Industries, Ltd .: methyl substitution degree 1.8), hydroxypropylmethyl cellulose (trade name Metroze 90SH-100: manufactured by Shin-Etsu Chemical Co., Ltd.) and valeroyl in place of 2-ethylhexanoyl chloride Valeroxypropylmethylvaleroylcellulose (C-6) was obtained in the same manner as in Synthesis Example 5 except that chloride was used. The solubility of this cellulose derivative (C-6) in water at 25 ° C. was less than 0.1% by mass (insoluble).

<Synthesis Example 7: Synthesis of valeroxybutyl methyl valeroyl cellulose (C-7)>
Valeroxybutylmethyl valeroyl cellulose (C-7) was synthesized in the same manner as in Synthesis Example 6 except that hydroxybutylmethylcellulose was used instead of hydroxypropylmethylcellulose (trade name Metroze 90SH-100: manufactured by Shin-Etsu Chemical) in Synthesis Example 6. Obtained. The solubility of this cellulose derivative (C-7) in water at 25 ° C. was less than 0.1% by mass (insoluble).

Note that the types and substitution degrees of hydrocarbon groups, the types and molar substitutions of alkyleneoxy groups, the types of acyl groups, and the degrees of acylation of the cellulose derivatives obtained above are described in Cellulose Communication 6, 73-79 (1999). Was observed and determined by ¹ H-NMR using the method described in ¹ ). The degree of substitution of the hydrocarbon group is the number of moles of the hydrocarbon group substituted on the glucose ring unit, and takes a value of 0 or more and less than 3. The molar substitution degree of the alkyleneoxy group is the number of moles of the alkyleneoxy group substituted on the glucose ring unit, and takes a value of 0 or more. The degree of acylation indicates the degree of substitution with an acyl group by esterifying a hydroxyl group present in the glucose ring or ether substituent of cellulose, and is represented by 0 or more and 100 or less.
Further, a colloid titration method is performed, and the degree of substitution of carboxyl groups or sulfonic acid groups in the cellulose derivatives (C-1) to (C-7) is less than 0.02 (that is, the content of carboxyl groups or sulfonic acid groups is It was confirmed that it was less than 0.5% by mass with respect to the cellulose derivative.

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

The type and degree of substitution of hydrocarbon groups, the type and molar substitution of alkyleneoxy groups, the type and degree of acylation of acyl groups, the number average molecular weight (Mn), and the mass average molecular weight (Mw) of the obtained cellulose derivative These are summarized in Table 1. Table 1 also shows the cellulose derivative (H-1) used in the comparative example.

<Examples 1 to 13 and Comparative Examples 1 to 4>
[Production of molded body]
Cellulose derivatives (C-1 to C-7, H-1), a polystyrene resin, a compatibilizing agent and an antioxidant were mixed at a blending ratio (mass%) shown in Table 3 to prepare a cellulose resin composition. This resin composition was supplied to a twin-screw kneading extruder (manufactured by Technobel Co., Ltd., Ultranano) to produce pellets, and then the obtained pellets were injected into an injection molding machine (FANUC Corporation Robot S-2000i, automatic injection molding). Machine), 4 × 10 × 80 mm multi-purpose test pieces were molded.

In Table 3, polystyrene resins, compatibilizers and antioxidants are as follows.
Polystyrene (PSt): G200C, Toyo Styrene Co., Ltd. HIPS resin (HIPS): H450, Toyo Styrene Co., Ltd. Compatibilizer: Modiper A4100, Nippon Oil & Fat Co., Ltd. (ethylene-glycidyl methacrylate-graft-acrylonitrile-styrene) resin)
Antioxidant: Phenolic antioxidant Irganox 1010, Ciba Specialty Chemicals Co., Ltd.

[Evaluation]
The following items were evaluated using the obtained multipurpose test piece. The evaluation results are shown in Table 3.

(Flexural modulus)
In accordance with ISO178, after adjusting the test piece molded by injection molding for 48 hours or more at 23 ° C ± 2 ° C, 50% ± 5% RH, the distance between fulcrums by Instron (Toyo Seiki, Strograph V50) The flexural modulus was measured at 64 mm and a test speed of 2 mm / min. The measurement is an average of three measurements.

(Bending strength)
In accordance with ISO178, after adjusting the test piece molded by injection molding for 48 hours or more at 23 ° C ± 2 ° C, 50% ± 5% RH, the distance between fulcrums by Instron (Toyo Seiki, Strograph V50) A bending test was performed at 64 mm and a test speed of 2 mm / min, and the maximum stress during the test was defined as the bending strength. The measurement is an average of three measurements.

(Heat deformation temperature (HDT))
In accordance with ISO75, a constant bending load (1.8 MPa) is applied to the center of the test piece (in the flatwise direction), the temperature is increased at a constant speed, and the temperature when the strain at the center reaches 0.34 mm ( ° C). As a thermal deformation temperature measuring device, HDT tester 6M-2 manufactured by Toyo Seiki Seisakusho Co., Ltd. was used. The measurement is an average of three measurements.

(Charpy impact strength)
In accordance with ISO 179, a notch having an incident angle of 45 ± 0.5 ° and a tip of 0.25 ± 0.05 mm is formed on a test piece molded by injection molding, 23 ° C. ± 2 ° C., 50% ± 5% RH Then, the impact strength was measured edgewise with a Charpy impact tester (manufactured by Toyo Seiki Seisakusho). The measurement is an average of three measurements.

(Dimensional stability evaluation)
In accordance with JIS K 7209, after the test piece was dried at 50 ° C. for 24 hours, mass measurement was performed, the sample was immersed in a constant temperature water bath at 23 ° C. for 24 hours, and the test piece was taken out and adhered to the surface. Water was removed and dimensional changes (length, width, thickness) before and after immersion were measured. The dimensional change rate (%) is {(length after immersion / length before immersion-1) × 100}, and the dimensional change rate (%) is {(width after immersion / width before immersion). -1) × 100}, and the dimensional change rate (%) of the thickness was determined by {(thickness after immersion / thickness before immersion-1) × 100}. Table 3 lists the average values of the three types of dimensional change rates of length, width, and thickness.

(Dispersibility evaluation)
Evaluation was made using an optical microscope (Nikon LV100) as an index of dispersibility. A microtome was sliced to 2 μm, observed at 1000 times, and evaluated according to the following criteria.
○: When aggregates are not observed Δ: When aggregates are slightly observed ×: When many aggregates are observed

(Evaluation of formability)
The moldability evaluation shows the moldability in an injection molding machine, and the meterability and the injection property were evaluated by the viscosity at a low shear rate (10 s ⁻¹ ) and a high shear rate (660 s ⁻¹ ), respectively. Viscosity measurement was performed using a rotary rheometer (Rheostress RS600: Thermo HAAKE). As shown in Table 2 below, the evaluation criteria were divided into four stages.

Examples 1 to 13 were excellent in flexural modulus, flexural strength, Charpy impact strength, heat resistance (HDT), and moldability. The comparative example 1 which does not contain a polystyrene resin was inferior to the sample of an Example in dimensional stability. Further, Comparative Examples 2 to 4 containing no cellulose derivative in the present invention had low Charpy impact strength.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application (Japanese Patent Application No. 2009-295101) filed on Dec. 25, 2009, the contents of which are incorporated herein by reference.

Claims

The hydrogen atom of the hydroxyl group contained in cellulose
A cellulose derivative comprising at least one group substituted in A) below and at least one group substituted in B) below;
Molding material containing polystyrene resin.
A) Hydrocarbon group: —R A
B) Acyl group: —CO—R B (R B represents a hydrocarbon group.)
The molding material according to claim 1, wherein the cellulose derivative further comprises at least one group in which a hydrogen atom of a hydroxyl group contained in cellulose is substituted by the following C).
C) a group containing an alkyleneoxy group: —R C2 —O— and an acyl group: —CO—R C1 (R C1 represents a hydrocarbon group, and R C2 represents an alkylene group having 2 to 4 carbon atoms. )
The molding material according to claim 2, wherein the C) group containing an alkyleneoxy group and an acyl group is a group containing a structure represented by the following general formula (3).

(Wherein R C1 represents a hydrocarbon group, R C2 represents an alkylene group having 2 to 4 carbon atoms, and n represents an integer of 1 or more.)
The molding material according to any one of claims 1 to 3, wherein R A is an alkyl group having 1 to 4 carbon atoms.
The molding material according to any one of claims 1 to 4, wherein R A is a methyl group or an ethyl group.
The molding material according to any one of claims 2 to 5, wherein R B and R C1 are each independently an alkyl group or an aryl group.
The molding material according to any one of claims 2 to 6, wherein R B and R C1 are each independently a methyl group, an ethyl group, or a propyl group.
The molding material according to any one of claims 1 to 6, wherein R B is a hydrocarbon group having a branched structure having 3 to 10 carbon atoms.
The molding material according to any one of claims 2 to 8, wherein the alkyleneoxy group is a group represented by the following formula (1) or (2).
The molding material according to any one of claims 1 to 9, wherein the cellulose derivative has substantially no carboxyl group, sulfonic acid group, or salt thereof.
The molding material according to any one of claims 1 to 10, wherein the cellulose derivative is insoluble in water.
The molding material according to any one of claims 1 to 11, wherein the polystyrene resin is polystyrene or high-impact polystyrene (HIPS).
The molding material according to any one of claims 1 to 12, further comprising a compatibilizing agent.
The molding material according to claim 13, wherein the compatibilizing agent has a polystyrene unit.
A molded body obtained by thermoforming the molding material according to any one of claims 1 to 14.
A method for producing a molded body, comprising a step of heating and molding the molding material according to any one of claims 1 to 14.
A housing for electrical and electronic equipment comprising the molded body according to claim 15.