JP2019026726A - Resin composition and resin molding - Google Patents

Abstract

To provide a resin composition that suppresses acetic acid from diffusing out of the resin composition.SOLUTION: A resin composition contains (A) cellulose acetate with a weight average molecular weight of 30,000 or more and 90,000 or less and with a degree of acetylation of 2.1 or more and 2.6 or less, and (B) an epoxidized oil composition.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition and a resin molded body.

Conventionally, various resin compositions have been provided and used for various applications. Resin compositions are particularly used in home appliances, various parts of automobiles, casings, and the like. Thermoplastic resins are also used in parts such as office equipment and electronic electrical equipment casings.
In recent years, plant-derived resins have been used, and cellulose derivatives are one of the conventionally known plant-derived resins.

  For example, Patent Document 1 discloses a cellulose ester resin composition composed of a plasticized cellulose ester and a carbodiimide compound.

  Patent Document 2 includes (A) a cellulose ester resin, (B) an epoxy group-containing plasticizer having an amount of 5 parts by mass to 10 parts by mass with respect to 100 parts by mass of the cellulose ester resin (A), (A) The amount with respect to 100 parts by mass of the cellulose ester resin is 10 parts by mass or more and 30 parts by mass or less, and (C) a nonreactive plasticizer having no functional group capable of reacting with the cellulose ester resin. A resin composition is disclosed.

JP 2006-183090 A Japanese Patent Laid-Open No. 2006-74795

  Conventionally, cellulose acetate in which part or all of hydroxyl groups in cellulose are substituted with acetyl groups has been used as a resin composition. However, when the resin composition containing cellulose acetate is stored for a long time under the conditions of high temperature, high humidity, and a closed system, the acetyl group is desorbed as acetic acid, and the desorbed acetic acid diffuses to the outside of the resin composition. Odors and metal corrosion may occur.

  The subject of the present invention is (A) when the weight average molecular weight of cellulose acetate is less than 30,000 or more than 90,000, (A) when the degree of acetyl substitution of cellulose acetate is less than 2.1 or more than 2.6, Or (B) It is providing the resin composition which suppressed that an acetic acid spread | diffused outside the resin composition compared with the case where an epoxidized oil composition is not included.

  The above object is achieved by the present invention described below.

The invention according to claim 1
(A) a cellulose acetate having a weight average molecular weight of 30,000 to 90,000 and an acetyl substitution degree of 2.1 to 2.6;
(B) an epoxidized oil composition;
A resin composition comprising:

The invention according to claim 2
The resin composition according to claim 1, wherein the (B) epoxidized oil composition contains an epoxidized oil having 5 to 80 carbon atoms as a main component.

The invention according to claim 3
The resin composition according to claim 1 or 2, wherein the (B) epoxidized oil composition is an epoxidized vegetable oil composition.

The invention according to claim 4
The resin composition according to claim 3, wherein the (B) epoxidized oil composition contains at least one of an epoxidized soybean oil composition and an epoxidized linseed oil composition.

The invention according to claim 5
The resin composition according to any one of claims 1 to 4, wherein the oxirane oxygen concentration in the (B) epoxidized oil composition is 3% by mass or more and 15% by mass or less.

The invention according to claim 6
The resin according to any one of claims 1 to 5, wherein a mass ratio (A) / (B) of the (A) cellulose acetate and the (B) epoxidized oil composition is 10 or more and 100 or less. Composition.

The invention according to claim 7 provides:
(C) The resin composition of any one of Claims 1-6 containing a plasticizer.

The invention according to claim 8 provides:
The resin composition according to claim 7, wherein the (C) plasticizer is at least one selected from the group consisting of an adipic acid ester-containing compound and a polyether ester compound.

The invention according to claim 9 is:
The resin composition according to claim 7 or 8, wherein a mass ratio (A) / (C) of (A) cellulose acetate and (C) plasticizer is 6 or more and 20 or less.

The invention according to claim 10 is:
A resin molded body in which the resin composition according to any one of claims 1 to 9 is molded.

The invention according to claim 11 is:
The resin molded body according to claim 10, wherein the resin molded body is an injection molded body.

  According to the invention of claim 1, 2, 3, or 4, when the weight average molecular weight of (A) cellulose acetate is less than 30,000 or more than 90,000, (A) the degree of acetyl substitution of cellulose acetate is 2. A resin composition in which acetic acid is prevented from diffusing to the outside of the resin composition is provided as compared with the case where it is less than 1 or more than 2.6, or compared with the case where (B) the epoxidized oil composition is not included.

  According to the invention which concerns on Claim 5, compared with the case where the density | concentration of the oxirane oxygen of (B) epoxidized oil composition is less than 3 mass%, the resin composition which suppressed that an acetic acid diffused outside the resin composition. Things are provided.

  According to the invention which concerns on Claim 6, compared with the case where mass ratio (A) / (B) of (A) cellulose acetate and (B) epoxidized oil composition is less than 10 or more than 100, acetic acid is resin. There is provided a resin composition in which diffusion to the outside of the composition is suppressed.

  According to the invention according to claim 7 or 8, only (A) cellulose acetate having a weight average molecular weight of 30,000 to 90,000 and an acetyl substitution degree of 2.1 to 2.6 and (B) an epoxidized oil composition only And a resin composition in which acetic acid is prevented from diffusing outside of the resin composition as compared with the case where no plasticizer is contained.

  According to the invention which concerns on Claim 9, compared with the case where mass ratio (A) / (C) of (A) cellulose acetate and (C) plasticizer is less than 6 or more than 20, acetic acid is a resin composition. There is provided a resin composition in which diffusion to the outside is suppressed.

  According to the invention which concerns on Claim 10 or 11, (A) The resin composition whose weight average molecular weight of a cellulose acetate is less than 30,000 or more than 90,000, (A) The acetyl substitution degree of a cellulose acetate is less than 2.1 Or compared with the resin molding which the resin composition which is more than 2.6, or (B) the resin composition which does not contain an epoxidized oil composition was shape | molded, it suppressed that an acetic acid diffused outside the resin composition. A resin molded body is provided.

  Hereinafter, embodiments of the resin composition and the resin molded body of the present invention will be described.

<Resin composition>
The resin composition according to this embodiment includes (A) cellulose acetate and (B) an epoxidized oil composition, and (A) cellulose acetate has a weight average molecular weight of 30,000 to 90,000 and a degree of substitution. 2.1 or more and 2.6 or less.

  Conventionally, cellulose derivatives that can be produced from non-edible resources have been used as resin materials having excellent environmental properties. In addition, the cellulose derivative can be expected to have a high elastic modulus as a resin material because of its hydrogen bonding property between the molecules and between the molecules, and may be developed for various uses such as metal replacement.

Among them, in particular, cellulose acetate is an environmentally friendly resin material because it is a non-edible resource and is a primary derivative that does not require chemical polymerization. In addition, since cellulose acetate has strong hydrogen bonding properties, it has a feature that it has an extremely high elastic modulus as a resin material.
However, since cellulose acetate substitutes a part of the hydroxyl group with an acetyl group in order to impart thermoplasticity, the acetyl group is easily removed as acetic acid. Therefore, when the resin composition containing cellulose acetate is stored for a long time in a high-temperature and high-humidity (for example, 60 ° C. and 85% RH or more) closed system, the acetic acid that has been released diffuses to the outside of the resin composition, thereby generating off-flavors. Certain metal corrosions (ie, vinegar syndrome) may occur.

On the other hand, in this embodiment, (A) cellulose acetate is mixed with (B) epoxidized oil composition, and (A) cellulose acetate has a weight average molecular weight of 30,000 to 90,000 and a degree of substitution of 2.1. By setting it as 2.6 or less above, it can suppress that acetic acid diffuses outside the resin composition.
The reason is not clear, but the following two can be considered.

First, the first reason that the diffusion of acetic acid is suppressed is to lower the kneading temperature and the molding temperature.
It is known that so-called vinegar syndrome is accelerated when the surroundings are in an acidic atmosphere. Cellulose acetate is heated during the kneading and injection molding processes, so part of the acetyl group is desorbed as acetic acid, and this acetic acid desorption triggers the surroundings to become an acidic atmosphere. It becomes easy to be released. And it is thought that the release of acetic acid is accelerated by repeating the release of acetic acid and surrounding acidification.
On the other hand, by combining a cellulose acetate having a weight average molecular weight of 30,000 or more and 90,000 or less and an acetyl substitution degree of 2.1 or more and 2.6 or less and an epoxidized oil, the kneading and molding temperature is reduced by 10 ° C. or more due to the lubricating effect. The As a result, the amount of acetic acid generated in the initial stage is reduced, and it is considered that the release of acetic acid during storage at high temperature, high humidity and closed system is reduced.

In particular, when the weight average molecular weight of the cellulose acetate is in the above range, compared to the case where the weight average molecular weight is less than 30,000, uniform dispersion of the epoxidized oil into the cellulose acetate is suppressed, and the epoxidized oil is also present on the surface. By becoming easy, the said lubrication effect becomes easy to be acquired. Further, since the weight average molecular weight of the cellulose acetate is in the above range, it is possible to suppress the inclusion of the epoxidized oil in the cellulose acetate in a biased state compared to the case where it exceeds 90,000, and the lubricating effect is obtained. It becomes easy to be done.
Furthermore, when the degree of acetyl substitution of cellulose acetate is in the above range, the kneading and molding temperatures can be easily reduced by inhibiting the hydrogen bonding force due to substitution of acetyl groups, compared to the case where the degree of acetyl substitution is less than 2.1. In addition, since the degree of acetyl substitution of cellulose acetate is in the above range, a decrease in meltability due to packing between substituents (acetyl groups) is suppressed compared to a case where the degree of substitution exceeds 2.6, and the kneading and molding temperatures are reduced. It becomes easy to reduce.

Next, as a second reason that the diffusion of acetic acid is suppressed, there is a trap effect of desorbed acetic acid due to the epoxy structure of the epoxidized oil.
Even when an epoxy compound having an epoxy structure has a low molecular weight (for example, epoxidized bisphenol), when the epoxy compound and cellulose acetate are kneaded, the epoxy group of the epoxy compound reacts with the acetyl group or hydroxyl group of cellulose acetate. To do. Therefore, the number of epoxy structures that trap the detached acetic acid is reduced, and the trapping effect is difficult to obtain.
On the other hand, since epoxidized oil has great steric hindrance, reaction with cellulose acetate hardly occurs, and even if reacted, one epoxy group remains because one molecule of epoxidized oil has multiple epoxy groups. The trap effect is considered to be exhibited.

  In particular, due to the weight average molecular weight of cellulose acetate being in the above range, the reaction between the epoxy group and the acetyl group or hydroxyl group is less likely to proceed than in the case where the weight average molecular weight is less than 30,000. The effect is easily obtained. On the other hand, when the weight average molecular weight of the cellulose acetate is in the above range, the epoxidized oil is prevented from being included in the cellulose acetate in a biased state compared to the case where it exceeds 90,000, and the trap effect is exhibited. It becomes easy.

  From the above, in this embodiment, it is considered that acetic acid can be prevented from diffusing outside the resin composition.

  Hereinafter, the components of the resin composition according to this embodiment will be described in detail.

[(A) Cellulose acetate]
The resin composition according to the present embodiment includes cellulose acetate having a weight average molecular weight of 30,000 to 90,000 and a substitution degree of 2.1 to 2.6.
Here, the cellulose acetate is a cellulose derivative in which at least a part of the hydroxyl group is substituted with an acetyl group, and specifically, a cellulose derivative represented by the following general formula (1).

In General Formula (1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or an acetyl group. n represents an integer of 2 or more. However, a part of n R ¹ , n R ² , and n R ³ represents an acetyl group.

  In general formula (1), the range of n is not particularly limited. What is necessary is just to determine according to the range of the target weight average molecular weight. For example, 120 or more and 330 or less are mentioned.

-Weight average molecular weight-
The weight average molecular weight of cellulose acetate is 30,000 or more and 90,000 or less. In addition, 40,000 or more and 90,000 or less are preferable and 60,000 or more and 80,000 or less are more preferable from the viewpoint of suppressing acetic acid from diffusing outside the resin composition.

  The weight average molecular weight (Mw) is a gel permeation chromatography device (GPC device: manufactured by Tosoh Corporation, HLC-8320GPC, column: TSKgel α-M) using a dimethylacetamide / lithium chloride = 90/10 (mass ratio) solution. Measured in terms of polystyrene.

-Degree of substitution-
The degree of substitution of cellulose acetate is 2.1 or more and 2.6 or less. In addition, from the viewpoint of suppressing the diffusion of acetic acid to the outside of the resin composition, it is preferably 2.15 or more and 2.6 or less, more preferably 2.2 or more and 2.5 or less. More preferably, it is 2 or more and 2.45 or less.

Here, the degree of substitution is an index indicating the degree to which the hydroxyl groups of cellulose are substituted with acetyl groups. That is, the degree of substitution is an index indicating the degree of acetylation of cellulose acetate. Specifically, the degree of substitution means an intramolecular average of the number of substitutions in which three hydroxyl groups in the D-glucopyranose unit of cellulose acetate are substituted with acetyl groups.
The degree of substitution is determined from the integral ratio of cellulose-derived hydrogen and acetyl group-derived peak by H ¹ -NMR (manufactured by JMN-ECA / JEOL RESONANCE). For example, the structural unit molecular weight of cellulose acetate is 263 when the substitution degree of the acetyl group is 2.4, and 284 when the substitution degree of the acetyl group is 2.9.

  As a suitable range of the polymerization degree of a cellulose acetate, 120 or more and 330 or less, 200 or more and 300 or less, 250 or more and 300 or less are mentioned, for example. When the degree of polymerization of cellulose acetate is in the above range, a resin molded article having improved impact strength can be easily obtained while suppressing a decrease in flexural modulus.

In addition, the polymerization degree of a cellulose acetate is calculated | required from a weight average molecular weight with the following procedures.
First, the weight average molecular weight of cellulose acetate is measured by the above method.
Next, the degree of polymerization of cellulose acetate is determined by dividing by the molecular weight of the structural unit of cellulose acetate.

  There is no restriction | limiting in particular in the manufacturing method of a cellulose acetate, For example, it manufactures suitably with the method of acetylating and low molecular weight (depolymerization) with respect to a cellulose, and deacetylating as needed. . Moreover, you may manufacture a cellulose acetate of a commercial item by performing low molecular weight (depolymerization) etc. so that it may become a predetermined weight average molecular weight.

[(B) Epoxidized oil composition]
The resin composition according to the present embodiment includes an epoxidized oil composition.
The epoxidized oil composition is an oil having an epoxy group.

-Synthesis | combination of an epoxidized oil composition Here, the synthesis | combination of an epoxidized oil composition is demonstrated.

First, the oil and fat will be described.
Oils and fats generally have a triglyceride structure in which fatty acids are bonded to the three —OH groups of glycerin, for example, the structure represented by the following (formula F). And, oils and fats usually have multiple fatty acids bonded as three fatty acids (R ^F1 , R ^F2 and R ^F3 in the following (formula F)) bonded to the —OH group portion of glycerin, and the three fatty acids. It is a mixture of a plurality of compounds having different combinations.

In (Formula F), R ^F1 , R ^F2 and R ^F3 each independently represent a fatty acid residue.
The fatty acid residue is a fatty acid, that is, a monovalent carboxylic acid having a chain structure (structural formula: R ^F4 —C (═O) —OH (R ^F4 is an alkyl group)), “—OH of the carboxy group. "Represents a group with the moiety removed.

As the fatty acid (R ^F1 , R ^F2 and R ^F3 in the above (Formula F)) bonded to the —OH group portion of glycerin in the oil and fat, a fatty acid having 5 to 80 (more preferably 8 to 60) carbon atoms is preferable. .
Specifically, cabrylic acid (carbon number: double bond number (hereinafter the same) = 8: 0), cabrynic acid (10: 0), lauric acid (12: 0), myristic acid (14: 0), palmitic Acid (16: 0), palmitoleic acid (16: 1), stearic acid (18: 0), oleic acid (18: 1), linoleic acid (18: 2), linolenic acid (18: 3), arachidic acid ( 20: 0), eicosenoic acid (20: 1), behenic acid (behenic acid) (22: 0), erucic acid (erucic acid) (22: 1), lignoceric acid (24: 0) and the like.
A typical structure example is shown below.

As an example, when a fatty acid contains a compound in which palmitic acid (16: 0), oleic acid (18: 1), and stearic acid (18: 0) are bonded as fatty acids to three —OH group portions of glycerin, The structure is, for example, the structure shown below (Formula F-1).


(Formula F-1)

  For example, flaxseed oil, which is a vegetable oil, generally contains palmitic acid (16: 0), palmitoleic acid (16: 1), stearic acid (18: 0), oleic acid (18: 1), linoleic acid (18 : 2), linolenic acid (18: 3), arachidic acid (20: 0), eicosenoic acid (20: 1) and the like are a mixture of compounds bonded to the three —OH group portions of glycerin. In addition, soybean oil, which is a vegetable oil, generally contains myristic acid (14: 0), palmitic acid (16: 0), palmitoleic acid (16: 1), stearic acid (18: 0), and oleic acid (18: 1), linoleic acid (18: 2), linolenic acid (18: 3), arachidic acid (20: 0), eicosenoic acid (20: 1), behenic acid (behenic acid) (22: 0), and lignoceric acid (24: 0) and the like are a mixture of compounds bonded to three —OH group portions of glycerin.

  The epoxidized oil composition in this embodiment has an epoxy group. This epoxidized oil composition can be obtained, for example, by epoxidizing fats and oils.

Here, epoxidation will be described.
The epoxidation of fats and oils is performed, for example, by adding one oxygen atom to a C═C double bond (ethylenic double bond) of the fats and oils to form a three-membered ring epoxy group. In addition, fats and oils have an ethylenic double bond in the residue (R ^F1 , R ^F2 and R ^F3 in the above (formula F)), for example, and this ethylenic double bond is epoxidized.
For example, the ethylenic double bond in the compound having the structure shown in (Formula F-1) in which palmitic acid (16: 0), oleic acid (18: 1), and stearic acid (18: 0) are bonded to glycerin When epoxidized, the structure is, for example, the structure shown below (formula F-2).


(Formula F-2)

  Examples of the epoxidizing agent include organic peracids such as performic acid, peracetic acid, perbenzoic acid, m-chloroperbenzoic acid, hydrogen peroxide, potassium peroxymonosulfate, and metal oxo complexes.

  Thus, for a mixture of oils and fats, that is, triglycerides having different structures in which a plurality of types of fatty acids are bonded to three —OH group parts in glycerin, the C═C double bond (ethylenic double bond) of the oils and fats The epoxidized oil composition in this embodiment can be obtained by epoxidizing at least a part.

-Carbon number of main component The epoxidized oil composition in this embodiment is a mixture of epoxidized oils having different structures. In the epoxidized oil composition, an epoxidized oil having 5 to 80 carbon atoms is preferably a main component. In the present specification, the “main component” means that the content ratio is 50 mass% or more by mass ratio. The content is more preferably 60% by mass or more, and still more preferably 70% by mass or more.
Moreover, it is more preferable that an epoxidized oil having 6 to 70 carbon atoms is a main component (more preferably 60% by mass or more, more preferably 70% by mass or more), and an epoxidized oil having 8 to 60 carbon atoms. More preferably, it is a main component (more preferably 60% by mass or more, more preferably 70% by mass or more).
By using an epoxidized oil having a carbon number in the above range as a main component, the effect of suppressing the diffusion of acetic acid to the outside of the resin composition is more easily achieved.

  The constituent ratio of the carbon number of the epoxidized oil contained in the epoxidized oil composition can be measured by the following method. Specifically, it can be measured by separating each component with a high performance liquid chromatograph (HPLC) apparatus using tetrahydrofuran as a solvent and measuring the mass spectrum of each component.

-Kind of epoxidized oil composition Even if the epoxidized oil composition in this embodiment is an epoxidized vegetable oil composition (that is, an epoxidized oil composition derived from vegetable oil), an epoxidized animal oil composition ( That is, it may be an epoxidized oil composition derived from animal fats and oils, or may be an epoxidized oil composition derived from other fats and oils.
Especially, it is preferable that it is an epoxidized vegetable oil composition, for example, it is preferable that it is an epoxidized oil composition which epoxidized vegetable oil and fat.

Examples of vegetable oils include linseed oil, soybean oil, castor oil, olive oil and the like.
Examples of animal fats include beef tallow and pork tallow.

  Among them, from the viewpoint that the effect of suppressing the diffusion of acetic acid to the outside of the resin composition is more easily achieved, an epoxidized oil composition derived from soybean oil (epoxidized soybean oil composition), linseed oil An epoxidized oil composition (epoxidized linseed oil composition) is preferable, and an epoxidized soybean oil composition and an epoxidized linseed oil composition are more preferable. That is, it is more preferable that the epoxidized oil composition contains at least one of an epoxidized soybean oil composition and an epoxidized linseed oil composition.

  In the present embodiment, a commercially available product may be used as the epoxidized oil composition. Commercial products of the epoxidized oil composition include “Chemizer LE-3000” (epoxidized linseed oil butyl ester) manufactured by Sanwa Synthetic Chemical Co., Ltd., and “Chemiserizer LE-2010” (epoxidized soybean oil-2- Ethyl hexyl ester), and "Chemizer LE-3010" (epoxidized linseed oil-2-ethylhexyl ester).

-Oxirane oxygen concentration As a parameter | index of the content rate of the epoxy group in the epoxidized oil composition in this embodiment, it is preferable that the density | concentration of the oxirane oxygen is 3 to 15 mass%, and 5 to 13 mass%. % Or less, more preferably 6% by mass or more and 11% by mass or less.
When the oxirane oxygen concentration is equal to or higher than the above lower limit value, the trapping effect of the desorbed acetic acid by the epoxy group is easily exhibited, and the effect of suppressing the diffusion of acetic acid to the outside of the resin composition is more easily achieved.
On the other hand, when the oxirane oxygen concentration is not more than the above upper limit, the reactivity of the epoxy group becomes excessive, and the effect that it can be controlled to bond with the hydroxyl group of cellulose acylate can be easily achieved.

-Content rate of epoxidized oil composition In the epoxidized oil composition in this embodiment, (B) mass ratio (A) / (B) with respect to (A) cellulose acetate of (B) epoxidized oil composition is 10 or more and 100 or less. It is preferable that In addition, mass ratio (A) / (B) becomes like this. More preferably, it is 15 or more and 90 or less, More preferably, it is 20 or more and 80 or less.
When the mass ratio (A) / (B) is 100 or less, the trapping effect of desorbed acetic acid by the epoxy group is easily exerted, and the effect of suppressing the diffusion of acetic acid to the outside of the resin composition is further exhibited. It becomes easy. On the other hand, when the mass ratio (A) / (B) is 10 or more, it is easy to achieve an effect that it is compatible with the exertion of the detachment acetic acid trap effect without impairing the original properties of cellulose acetate such as mechanical strength. Become.

[(C) Plasticizer]
The resin composition according to this embodiment may further contain a plasticizer.
Examples of the plasticizer include adipic acid ester-containing compounds, polyether ester compounds, condensed phosphate ester compounds, sebacic acid ester compounds, glycol ester compounds, acetate ester compounds, dibasic acid ester compounds, phosphate ester compounds, and phthalic acid. Examples include ester compounds, camphor, citrate ester compounds, stearate ester compounds, metal soaps, polyol compounds, and polyalkylene oxide compounds.
Among these, it is preferable to include at least one plasticizer selected from the group consisting of an adipic acid ester-containing compound and a polyether ester compound from the viewpoint of easily suppressing a dimensional change when the resin molded body is formed.

-Adipate-containing compound-
The adipic acid ester-containing compound (compound containing adipic acid ester) is a compound of adipic acid ester alone or a mixture of adipic acid ester and a component other than adipic acid ester (a compound different from adipic acid ester) Indicates. However, the adipic acid ester-containing compound may contain 50% by mass or more of the adipic acid ester with respect to all components.

  Examples of the adipic acid ester include adipic acid diester and adipic acid polyester. Specifically, an adipic acid diester represented by the following general formula (AE-1), an adipic acid polyester represented by the following general formula (AE-2), and the like can be given.

In General Formulas (AE-1) and (AE-2), R ^AE1 and R ^AE2 are each independently an alkyl group or a polyoxyalkyl group [— (C _x H _2X —O) _y —R ^A1 ] ( Where R ^A1 represents an alkyl group, x represents an integer of 1 to 6, and y represents an integer of 1 to 6.
R ^AE3 represents an alkylene group.
m1 represents an integer of 1 to 5.
m2 represents an integer of 1 or more and 10 or less.

In general formulas (AE-1) and (AE-2), the alkyl group represented by R ^AE1 and R ^AE2 is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. . The alkyl group represented by R ^AE1 and R ^AE2 may be linear, branched or cyclic, but is preferably linear or branched.

In the general formulas (AE-1) and (AE-2), in the polyoxyalkyl group [— (C _x H _2X —O) _y —R ^A1 ] represented by R ^AE1 and R ^AE2 , the alkyl group represented by R ^A1 is An alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable. The alkyl group represented by R ^A1 may be linear, branched or cyclic, but is preferably linear or branched. x represents an integer of 1 to 6. y represents an integer of 1 to 6.

In general formula (AE-2), the alkylene group represented by R ^AE3 is preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 4 carbon atoms. The alkylene group may be linear, branched or cyclic, but is preferably linear or branched.

  In general formulas (AE-1) and (AE-2), the group represented by each symbol may be substituted with a substituent. Examples of the substituent include an alkyl group, an aryl group, and a hydroxyl group.

  The molecular weight (or weight average molecular weight) of the adipic acid ester is preferably 100 or more and 10,000 or less, and more preferably 200 or more and 3000 or less. In addition, a weight average molecular weight is the value measured by the measuring method similar to the weight average molecular weight of the above-mentioned polyetherester compound.

  Hereinafter, although the specific example of an adipic acid ester containing compound is shown, it is not necessarily restricted to this.

-Polyetherester compound-
Specific examples of the polyetherester compound include a polyetherester compound represented by the general formula (EE).

In general formula (EE), ^REE1 and ^REE2 each independently represent an alkylene group having 2 to 10 carbon atoms. ^AEE1 and ^AEE2 each independently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. m represents an integer of 1 or more.

In general formula (EE), as an alkylene group which ^REE1 represents, a ^C3-C10 alkylene group is preferable and a C3-C6 alkylene group is more preferable. The alkylene group represented by ^REE1 may be linear, branched, or cyclic, but is preferably linear.
When the number of carbon atoms of the alkylene group represented by ^REE1 is 3 or more, a decrease in fluidity of the resin composition is suppressed, and thermoplasticity is easily exhibited. When the alkylene group represented by ^REE1 has 10 or less carbon atoms or the alkylene group represented by ^REE1 is linear, the affinity with cellulose acetate is likely to increase. For this reason, when the alkylene group represented by ^REE1 is linear, and the carbon number is in the above range, the moldability of the resin composition is improved.
From these viewpoints, the alkylene group represented by ^REE1 is particularly preferably an n-hexylene group (— (CH ₂ ) ₆ —). That is, the polyether ester compound is preferably a compound representing an n-hexylene group (— (CH ₂ ) ₆ —) as R ^EE1 .

In general formula (EE), as an alkylene group which ^REE2 represents, a ^C3-C10 alkylene group is preferable and a C3-C6 alkylene group is more preferable. The alkylene group represented by ^REE2 may be linear, branched or cyclic, but is preferably linear.
When the number of carbon atoms of the alkylene group represented by ^REE2 is 3 or more, a decrease in fluidity of the resin composition is suppressed and thermoplasticity is easily exhibited. When the alkylene group represented by ^REE2 has a carbon number of 10 or less or the alkylene group represented by ^REE2 is linear, affinity with cellulose acetate is likely to increase. For this reason, when the alkylene group represented by ^REE2 is linear and the carbon number is in the above range, the moldability of the resin composition is improved.
From these viewpoints, the alkylene group represented by ^REE2 is particularly preferably an n-butylene group (— (CH ₂ ) ₄ —). That is, the polyether ester compound is preferably a compound representing an n-butylene group (— (CH ₂ ) ₄ —) as ^REE2 .

In the general formula ^(EE), the alkyl group represented by ^{A EE1,} and ^{A EE2} is an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 2 to 4 carbon atoms. A ^EE1, and alkyl group represented by A ^EE2 are linear, branched, and may be either cyclic, branched is preferred.
Aryl groups A ^EE1, and represented by A ^EE2 is an aryl group having 6 to 12 carbon atoms, a phenyl group, an unsubstituted aryl group such as a naphthyl group, or t- butyl phenyl, substituted phenyl such as hydroxyphenyl group Groups.
A ^EE1, and aralkyl group represented by ^{A EE2,} a group represented by -R A -Ph. R ^A represents a linear or branched alkylene group having 1 to 6 carbon atoms (preferably 2 to 4 carbon atoms). Ph represents an unsubstituted phenyl group or a substituted phenyl group substituted with a linear or branched alkyl group having 1 to 6 carbon atoms (preferably 2 to 6 carbon atoms). Specific examples of the aralkyl group include unsubstituted aralkyl groups such as benzyl group, phenylmethyl group (phenethyl group), phenylpropyl group, and phenylbutyl group, or substituted groups such as methylbenzyl group, dimethylbenzyl group, and methylphenethyl group. An aralkyl group is mentioned.

At least one of A ^EE1, and ^{A EE2} is preferably an aryl group or an aralkyl group. In other words, a polyether ester ^{compound, A EE1,} and preferably (preferably a phenyl group) an aryl group as at least one of ^{A EE2} is a compound represented or aralkyl ^{group, A EE1,} and aryl groups as both ^{A EE2} ( A compound that preferably represents a phenyl group) or an aralkyl group is preferred.

  Next, the characteristics of the polyetherester compound will be described.

The weight average molecular weight (Mw) of the polyetherester compound is preferably from 450 to 650, more preferably from 500 to 600.
When the weight average molecular weight (Mw) is 450 or more, bleeding (a phenomenon of precipitation) becomes difficult. When the weight average molecular weight (Mw) is 650 or less, the affinity with cellulose acetate tends to increase. For this reason, when a weight average molecular weight (Mw) is made into the said range, the moldability of a resin composition will improve.
In addition, the weight average molecular weight (Mw) of a polyetherester compound is a value measured by a gel permeation chromatograph (GPC). Specifically, the molecular weight measurement by GPC uses Tosoh Co., Ltd. product and HPLC1100 as a measuring apparatus, and uses Tosoh Co., Ltd. column and TSKgel GMHHR-M + TSKgel GMHHR-M (7.8 mm ID30cm). Perform with chloroform solvent. The weight average molecular weight is calculated from the measurement result using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

The viscosity of the polyether ester compound at 25 ° C. is preferably 35 mPa · s or more and 50 mPa · s or less, and more preferably 40 mPa · s or more and 45 mPa · s or less.
When the viscosity is 35 mPa · s or more, dispersibility in cellulose acetate is easily improved. When the viscosity is 50 mPa · s or less, the anisotropy of the dispersion of the polyetherester compound hardly appears. For this reason, when a viscosity is made into the said range, the moldability of a resin composition will improve.
The viscosity is a value measured with an E-type viscometer.

The solubility parameter (SP value) of the polyether ester compound is preferably from 9.5 to 9.9, and more preferably from 9.6 to 9.8.
When the solubility parameter (SP value) is 9.5 or more and 9.9 or less, the dispersibility in cellulose acetate is easily improved.
The solubility parameter (SP value) is a value calculated by the method of Fedor. Specifically, the solubility parameter (SP value) is, for example, Polym. Eng. Sci. , Vol. 14, p. 147 (1974), the SP value is calculated by the following formula.
Formula: SP value = √ (Ev / v) = √ (ΣΔei / ΣΔvi)
(Wherein Ev: evaporation energy (cal / mol), v: molar volume (cm ³ / mol), Δei: evaporation energy of each atom or atomic group, Δvi: molar volume of each atom or atomic group)
The solubility parameter (SP value) employs (cal / cm ³ ) ^1/2 as a unit, but the unit is omitted in accordance with common practice and expressed in a dimensionless manner.

  Hereinafter, although the specific example of a polyetherester compound is shown, it is not necessarily restricted to this.

When the resin composition according to the present embodiment includes the above-described (C) plasticizer, the mass ratio “(A) / (C)” of (A) cellulose acetate and (C) plasticizer is 6 or more and 20 or less. Preferably, it is 7 or more and 18 or less, more preferably 8 or more and 16 or less.
When the mass ratio (A) / (C) is 20 or less, the mobility of the epoxidized oil composition is not impaired, and the trapping effect of detached acetic acid is easily achieved. On the other hand, when the mass ratio (A) / (total plasticizer amount) is 6 or more, the epoxidized oil composition itself does not desorb and the effect of the desorbed acetic acid trap is easily achieved.

The plasticizer preferably contains at least one plasticizer (C1) selected from the group consisting of an adipic acid ester-containing compound and a polyetherester compound. In that case, (A) cellulose acetate and the plasticizer ( The mass ratio (A) / (C1) to C1) is preferably 6 or more and 20 or less, more preferably 7 or more and 18 or less, and still more preferably 8 or more and 16 or less.
When the mass ratio (A) / (C1) is 20 or less, the mobility of the epoxidized oil composition is not impaired, and the effect of trapping desorbed acetic acid is easily achieved. On the other hand, when the mass ratio (A) / (C1) is 6 or more, desorption of the epoxidized oil composition itself does not occur, and the effect of the desorption acetic acid trap is easily achieved.

[Other ingredients]
The resin composition according to the present embodiment may further include other components than those described above as necessary. Examples of other components include flame retardants, compatibilizers, antioxidants, mold release agents, light proofing agents, weathering agents, colorants, pigments, modifiers, anti-drip agents, antistatic agents, and hydrolysis inhibitors. , Fillers, reinforcing agents (glass fiber, carbon fiber, talc, clay, mica, glass flake, milled glass, glass beads, crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, etc.).
Moreover, you may add components (additive), such as an acid acceptor and a reactive trap agent, as needed. Examples of the acid acceptor include oxides such as magnesium oxide and aluminum oxide; metal hydroxides such as magnesium hydroxide, calcium hydroxide, aluminum hydroxide and hydrotalcite; calcium carbonate; talc;
Examples of reactive trapping agents include epoxy compounds, acid anhydride compounds, carbodiimide compounds, and the like.
The content of these components is preferably 0% by mass to 5% by mass with respect to the total amount of the resin composition. Here, “0 mass%” means that other components are not included.

In particular, the addition of a carbodiimide compound to cellulose acetate activates the acetyl group of cellulose acetate and promotes self-binding, thereby suppressing the elimination of acetic acid. However, when a carbodiimide compound is added to cellulose acetate, it may be colored brown due to a conjugated system due to self-reaction, and the thermoplasticity and melt moldability may be impaired due to a significant increase in melt viscosity. .
That is, the resin composition of this embodiment may contain a carbodiimide compound, but by not containing a carbodiimide compound, acetic acid may diffuse outside the resin composition while suppressing the above-described coloring and increase in melt viscosity. It is suppressed. And from a viewpoint of suppression of coloring and suppression of a raise of melt viscosity, it is still more preferable that a resin composition does not contain a carbodiimide compound, or content of the carbodiimide compound with respect to the whole resin composition is 1 mass% or less.
Here, the carbodiimide compound refers to a compound having one or more —N═C═N— structures. Moreover, as a carbodiimide compound, a linear carbodiimide compound, a cyclic carbodiimide compound, etc. are mentioned, for example.

The resin composition according to the present embodiment may contain a resin other than the above resin ((A) cellulose acetate). However, when other resins are included, the content of the other resins with respect to the total amount of the resin composition is preferably 5% by mass or less, and preferably less than 1% by mass. It is more preferable that other resins are not contained (that is, 0% by mass).
Examples of other resins include conventionally known thermoplastic resins, and specifically, polycarbonate resins; polypropylene resins; polyester resins; polyolefin resins; polyester carbonate resins; polyphenylene ether resins; Polyethersulfone resin; Polyarylene resin; Polyetherimide resin; Polyacetal resin; Polyvinyl acetal resin; Polyketone resin; Polyetherketone resin; Polyetheretherketone resin; Polyarylketone resin; Polyethernitrile resin; Imidazole resin; polyparabanic acid resin; selected from the group consisting of aromatic alkenyl compounds, methacrylic acid esters, acrylic acid esters, and vinyl cyanide compounds A vinyl polymer or copolymer obtained by polymerizing or copolymerizing at least one kind of vinyl monomer; a diene-aromatic alkenyl compound copolymer; a vinyl cyanide-diene-aromatic alkenyl compound copolymer; Aromatic alkenyl compound-diene-vinyl cyanide-N-phenylmaleimide copolymer; vinyl cyanide- (ethylene-diene-propylene (EPDM))-aromatic alkenyl compound copolymer; vinyl chloride resin; chlorinated vinyl chloride Resin; and the like. Moreover, a core-shell type butadiene-methyl methacrylate copolymer is also exemplified. These resins may be used alone or in combination of two or more.

[Method for Producing Resin Composition]
The manufacturing method of the resin composition which concerns on this embodiment has the process of preparing the resin composition containing (A) cellulose acetate and (B) epoxidized oil composition, for example.
The resin composition according to this embodiment is obtained by melt-kneading a mixture containing (A) cellulose acetate and (B) an epoxidized oil composition and, if necessary, a plasticizer and other components. Manufactured. In addition, the resin composition according to the present embodiment is produced, for example, by dissolving the above components in a solvent.
Examples of the melt-kneading means include known means, and specific examples include a twin screw extruder, a Henschel mixer, a Banbury mixer, a single screw extruder, a multi-screw extruder, and a kneader.

<Resin molding>
The resin molded body according to the present embodiment is molded using the resin composition according to the present embodiment.
The molding method of the resin molded body according to the present embodiment is preferably injection molding because it has a high degree of freedom in shape. In this respect, the resin molded body is preferably an injection molded body obtained by injection molding.
The cylinder temperature of injection molding is, for example, 200 ° C. or more and 300 ° C. or less, and preferably 240 ° C. or more and 280 ° C. or less. The mold temperature for injection molding is, for example, 40 ° C. or higher and 90 ° C. or lower, and more preferably 60 ° C. or higher and 80 ° C. or lower.
The injection molding may be performed using a commercially available apparatus such as NEX500 manufactured by Nissei Plastic Industrial Co., Ltd., NEX150 manufactured by Nissei Plastic Industrial Co., Ltd., NEX70000 manufactured by Nissei Plastic Industrial Co., Ltd., PNX40 manufactured by Nissei Plastic Industrial Co., Ltd., SE50D manufactured by Sumitomo Machinery Co., Ltd. Good.

  The molding method for obtaining the resin molded body according to the present embodiment is not limited to the above-described injection molding. For example, extrusion molding, blow molding, hot press molding, calendar molding, coating molding, cast molding, dipping molding, vacuum Molding, transfer molding or the like may be applied.

  The resin molded body according to the present embodiment is suitably used for applications such as electronic / electrical equipment, office equipment, home appliances, automobile interior materials, and containers. More specifically, casings for electronic / electrical equipment and home appliances; various parts of electronic / electrical equipment and home appliances; interior parts for automobiles; storage cases such as CD-ROM and DVD; tableware; beverage bottles; Wrap material; film; sheet;

  EXAMPLES The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples. Note that “part” means “part by mass” unless otherwise specified.

<(A) Preparation of cellulose acylate>
-Synthesis of cellulose acetate (CA1)-
Acetylation: 3 parts of cellulose powder (manufactured by Nippon Paper Chemical Co., Ltd., KC Flock W50), 0.05 part of sulfuric acid, 30 parts of acetic acid and 6 parts of acetic anhydride are placed in a reaction vessel and stirred at 20 ° C. for 4 hours. Cellulose was acetylated.

  Deacetylation and molecular weight reduction: After completion of the stirring, 3 parts of acetic acid and 1.2 parts of pure water were immediately added to the acetylated solution, followed by stirring at 20 ° C. for 30 minutes. After the stirring, 4.5 parts of 0.2M hydrochloric acid aqueous solution was added, heated to 75 ° C. and stirred for 5 hours. This solution was dropped into 200 parts of pure water over 2 hours, allowed to stand for 20 hours, and then filtered through a filter having a pore size of 6 μm to obtain 4 parts of white powder.

  Washing: The obtained white powder was washed with pure water using a filter press (SF (PP)) until the conductivity reached 50 μS or less. After washing, it was dried.

  Post-treatment: To 3 parts of the dried white powder, 0.2 part of calcium acetate and 30 parts of pure water were added, stirred at 25 ° C. for 2 hours, and then filtered. The powder obtained by filtration was dried at 60 ° C. for 72 hours to obtain 2.5 parts of cellulose acetate (CA1).

-Synthesis of cellulose acetate (CA2)-
Cellulose acetate (CA2) was obtained in the same manner as CA1, except that 0.05 part of sulfuric acid used for acetylation was changed to 0.10 parts.

-Synthesis of cellulose acetate (CA3)-
Cellulose acetate (CA3) was obtained in the same manner as CA1, except that 0.05 part of sulfuric acid used for acetylation was changed to 0.01 part.

-Synthesis of cellulose acetate (CA4)-
In deacetylation and molecular weight reduction, cellulose acetate (CA4) was obtained in the same manner as CA1, except that the place of stirring for 5 hours was changed to 7 hours.

-Synthesis of cellulose acetate (CA5)-
In deacetylation and molecular weight reduction, cellulose acetate (CA5) was obtained in the same manner as CA1, except that the stirring for 5 hours was changed to 4 hours 30 minutes.

-Synthesis of cellulose acetate (CA6)-
Cellulose acetate (CA6) was obtained in the same manner as CA1, except that the solution obtained by acetylation was allowed to stand at room temperature (25 ° C.) for 16 hours and then deacetylated and reduced in molecular weight.

-Synthesis of cellulose acetate (CA7)-
In deacetylation and molecular weight reduction, cellulose acetate (CA7) was obtained in the same manner as CA1, except that stirring at 75 ° C. for 5 hours was performed at 65 ° C. for 7 hours.

-Synthesis of cellulose acetate (CA8)-
In deacetylation and molecular weight reduction, cellulose acetate (CA8) was obtained in the same manner as CA1, except that stirring at 75 ° C. for 5 hours was performed at 80 ° C. for 4 hours.

-Preparation of cellulose acetate (CA9)-
A commercially available cellulose acetate (manufactured by Daicel, L50) was prepared as (CA9).

-Preparation of cellulose acetate (CA10)-
A commercially available cellulose acetate (manufactured by Daicel, L20) was prepared as (CA10).

-Preparation of cellulose acetate (CA11)-
A commercially available cellulose acetate (manufactured by Daicel, LT-35) was prepared as (CA11).

<Measurement of weight average molecular weight and substitution degree>
The weight average molecular weight of the cellulose acetate was measured in terms of polystyrene using a dimethylacetamide / lithium chloride = 90/10 (mass ratio) solution with a GPC apparatus (manufactured by Tosoh Corporation, HLC-8320GPC, column: TSKgelα-M).
The degree of substitution of cellulose acetate was determined from the integral ratio of cellulose-derived hydrogen and acetyl group-derived hydrogen peak by H ¹ -NMR (manufactured by JMN-ECA / JEOL RESONANCE).
The results of measuring the weight average molecular weight and substitution degree of each prepared cellulose by this method are shown in the following table.

<Preparation of (B) Epoxidized oil composition>
The following commercial products were prepared as epoxidized oil compositions (EPO1) to (EPO5).
(EPO1): Epoxidized soybean oil, “Chemisizer SE-100” manufactured by Sanwa Synthetic Chemical Co., Ltd.
・ Contains epoxidized oil having 40 to 60 carbon atoms as a main component (specifically, 60 mass% or more) ・ Oxirane oxygen concentration: 5.5 mass%

(EPO2): Epoxidized soybean oil, “Sansocizer E-2000H” manufactured by Shin Nippon Chemical Co., Ltd.
・ Containing epoxidized oil having 40 to 60 carbon atoms as a main component (specifically, containing 60% by mass or more)
・ Oxirane oxygen concentration: 6.7% by mass

(EPO3): Epoxidized soybean oil, “ADEKA SIZER O130P” manufactured by ADEKA Corporation,
・ Containing epoxidized oil having 50 to 80 carbon atoms as the main component (specifically, containing 60% by mass or more)
・ Oxirane oxygen concentration: 6.7% by mass

(EPO4): Epoxidized linseed oil, “Sanso Sizer E-9000H” manufactured by Shin Nippon Chemical Co., Ltd.,
・ Containing epoxidized oil having 50 to 80 carbon atoms as the main component (specifically, containing 60% by mass or more)
・ Oxirane oxygen concentration: 8.5% by mass

(EPO5): Epoxidized linseed oil “ADEKA SIZER O180A” manufactured by ADEKA Corporation,
・ Containing epoxidized oil having 50 to 80 carbon atoms as the main component (specifically, containing 60% by mass or more)
・ Oxirane oxygen concentration: 9.1% by mass

<(C) Preparation of plasticizer>
Commercially available plasticizers shown in Table 2 were prepared.

<Preparation of carbodiimide compound>
(Synthesis of carbodiimide compound (CI1))
590 parts of 4,4′-dicyclohexyl metadiisocyanate, 62.2 parts of cyclohexyl isocyanate, and 6.12 parts of catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) are mixed, and 180 ° For 48 hours to synthesize poly (4,4′-dicyclohexylmethanecarbodiimide) having a polymerization degree of 10 to obtain a carbodiimide compound (CI1).

(Preparation of carbodiimide compound (CI2))
A commercially available carbodiimide compound (manufactured by Kawaguchi Chemical Industry, 1,3-diisopropylcarbodiimide) was prepared as a carbodiimide compound (CI2).

<Examples and Comparative Examples>
-Kneading and injection molding-
Table 3 and Table 4 show the cylinder temperatures in terms of the charged composition ratio (parts by mass) of cellulose acetate (A), epoxidized oil composition (B), plasticizer (C), and carbodiimide compound shown in Table 3 and Table 4. Therefore, it adjusted and knead | mixed with the biaxial kneading apparatus (Toshiki machine make, TEX41SS), and obtained the resin composition (pellet).
About the obtained pellet, the cylinder temperature was adjusted according to Table 3 and Table 4 so that the injection peak pressure did not exceed 180 MPa using an injection molding machine (manufactured by Nissei Plastic Industrial Co., Ltd., NEX140III), and a D2 test piece (60 × 60 mm X thickness 2 mm).

[Evaluation]
-Evaluation of acetic acid diffusion rate-
One D2 test piece obtained in each example and comparative example was allowed to stand at a temperature of 25 ° C. for 48 hours, and then the generated gas collector (at MSD, MSTD-285M, which had a temperature of 65 ° C. and a humidity of 85% RH). ). Then, air was supplied (purged) at 50 ml / min for 15 minutes in the generated gas collecting device, and the air (purge gas) that passed through the generated gas replenishing device was collected. The amount of acetic acid in the collected gas was measured using a gas chromatograph mass spectrometer (manufactured by Shimadzu Corporation, QP-2010) with a heat desorption device (manufactured by PerkinElmer, TurboMatrix 350), and acetic acid diffusion from the D2 test piece. The speed was determined. The results are shown in the table below.

-Evaluation of melt viscosity-
The melt viscosity at a cylinder temperature of 230 ° C. and a shear rate of 1216 sec ⁻¹ was measured with a capillary rheometer (manufactured by Toyo Seiki Seisakusho, Capillograph 1D) using the pellets of each Example and Comparative Example. The results are shown in the table below.

-Evaluation of color difference-
Using the D2 test piece obtained in each example and comparative example, a color difference ΔE with respect to a calibration standard white plate was measured with a spectrocolorimeter (manufactured by Konica Minolta, CM-3700A). The results are shown in the table below.

  From the result shown in the said table | surface, it turns out that an acetic acid can suppress spreading | diffusion outside the resin composition compared with a comparative example in a present Example.

Claims (11)

(A) a cellulose acetate having a weight average molecular weight of 30,000 to 90,000 and an acetyl substitution degree of 2.1 to 2.6;
(B) an epoxidized oil composition;
A resin composition comprising:   The resin composition according to claim 1, wherein the (B) epoxidized oil composition contains an epoxidized oil having 5 to 80 carbon atoms as a main component.   The resin composition according to claim 1 or 2, wherein the (B) epoxidized oil composition is an epoxidized vegetable oil composition.   The resin composition according to claim 3, wherein the (B) epoxidized oil composition contains at least one of an epoxidized soybean oil composition and an epoxidized linseed oil composition.   The resin composition according to any one of claims 1 to 4, wherein the oxirane oxygen concentration in the (B) epoxidized oil composition is 3% by mass or more and 15% by mass or less.   The resin according to any one of claims 1 to 5, wherein a mass ratio (A) / (B) of the (A) cellulose acetate and the (B) epoxidized oil composition is 10 or more and 100 or less. Composition.   (C) The resin composition of any one of Claims 1-6 containing a plasticizer.   The resin composition according to claim 7, wherein the (C) plasticizer is at least one selected from the group consisting of an adipic acid ester-containing compound and a polyether ester compound.   The resin composition according to claim 7 or 8, wherein a mass ratio (A) / (C) of (A) cellulose acetate and (C) plasticizer is 6 or more and 20 or less.   A resin molded body in which the resin composition according to any one of claims 1 to 9 is molded.   The resin molded body according to claim 10, wherein the resin molded body is an injection molded body.