JP7336870B2 - resin composition - Google Patents

Description

The present invention relates to a resin composition and a method for producing the resin composition.

Conventionally, petroleum-derived plastic materials, which are a finite resource, have been widely used, but in recent years, technologies that have a low impact on the environment have come into the spotlight. Materials using cellulose have attracted attention.

For example, Patent Document 1 discloses cellulose microfibrils having a specific degree of surface substitution in which the hydroxyl functional groups are etherified with an organic compound for the purpose of providing microfibrils that can be dispersed in an organic medium. is disclosed (claim 1).

Japanese Patent Publication No. 2002-524618

However, the cellulose microfibrils of Patent Document 1 are not fully satisfactory in dispersibility in organic solvents and resins. Furthermore, when a resin composition obtained by blending cellulose with a resin is molded, it tends to be colored and look unattractive.

TECHNICAL FIELD The present invention relates to a resin composition containing modified cellulose, which exhibits excellent rigidity and can be molded into a molded article with suppressed coloration. Further, the present invention relates to providing a method for producing such a resin composition.

That is, the present invention relates to the following [1] to [2].
[1] a polypropylene resin, and one or more substituents selected from the group consisting of a substituent represented by the following formula (1), a substituent represented by (2) and a substituent represented by (3) A resin composition containing modified cellulose in which groups are independently bonded to cellulose via ether bonds.
-R ¹ (1)
—CH ₂ —CH(OH)—CH ₃ (2)
_-CH2 -CH(OH) _-CH2 - _CH3 (3)
[Wherein, R ¹ in general formula (1) represents a linear or branched alkyl group having 3 or 4 carbon atoms]
[2] a polypropylene resin, and one or more substituents selected from the group consisting of a substituent represented by the formula (1), a substituent represented by (2) and a substituent represented by (3) A method for producing a resin composition, comprising a step of mixing modified cellulose in which groups are each independently bonded to cellulose via ether linkages.

According to the present invention, it is possible to provide a resin composition containing modified cellulose, which exhibits excellent rigidity and can be molded into a molded article with suppressed coloration. Furthermore, according to the present invention, it is possible to provide a method for producing such a resin composition.

<Resin composition>
The resin composition of the present invention is a resin composition obtained by blending a polypropylene resin and a modified cellulose having a specific substituent. The modified cellulose has at least one substituent selected from the group consisting of the substituent represented by the formula (1), the substituent represented by (2) and the substituent represented by (3) are each independently bound to cellulose via an ether bond.

Conventionally, efforts have been made to improve mechanical properties by blending cellulose with highly hydrophobic resins, but in order to disperse cellulose in resins, it was necessary to increase the hydrophobicity of cellulose. Therefore, a hydrocarbon group having a relatively large number of carbon atoms has been used as a substituent to be introduced into cellulose. However, the introduction efficiency of such hydrocarbon groups into cellulose was not necessarily high. Therefore, the present inventors have investigated conditions under which even a hydrocarbon group having a relatively small number of carbon atoms can achieve high dispersion in a resin. As a result, by limiting the resin to a polypropylene resin and further limiting the substituents to be introduced to specific ones, it is possible to achieve dispersion of the modified cellulose in the resin, which is accompanied by the blending of the cellulose. It was found that coloring can also be suppressed.

Although the mechanism by which this effect is exerted is not necessarily clear, cellulose is hydrophobized even with a hydrocarbon group having a relatively small number of carbon atoms, making it dispersible in polypropylene resin, and the primary hydroxy group at the 6-position of the glucose unit is It is presumed that the etherification suppresses the decomposition of cellulose and suppresses coloration.

[Polypropylene resin]
The resin constituting the resin composition of the present invention is a polypropylene resin. When a thermoplastic resin other than polypropylene resin, such as polyethylene resin, is used, unexpectedly, the desired effect is not exhibited.

[Modified cellulose]
The modified cellulose in the present invention is characterized in that a specific substituent is bonded to cellulose through an ether bond. In the present specification, "bonded via an ether bond" means a state in which a substituent reacts with a hydroxyl group of cellulose to form an ether bond.

[Average fiber diameter]
The average fiber diameter of the modified cellulose is preferably 5 μm or more from the viewpoints of improving the mechanical strength of the resin composition, improving the handleability of the modified cellulose, facilitating availability, and reducing the cost. , more preferably 7 μm or more, and still more preferably 10 μm or more. Although the upper limit is not particularly set, it is preferably 100 μm or less, more preferably 70 μm or less, still more preferably 50 μm or less, and still more preferably from the viewpoint of improving the handling properties of the modified cellulose and the mechanical strength of the resin composition. It is 40 μm or less, more preferably 30 μm or less. In addition, in this specification, the average fiber diameter of the modified cellulose is measured by the method described in Examples below.

Also, the modified cellulose may have a fine average fiber diameter. For example, the modified cellulose can be pulverized by treatment using a high-pressure homogenizer or the like in an organic solvent. The average fiber diameter of the refined modified cellulose may be, for example, about 1 to 500 nm, and from the viewpoint of improving the heat resistance of the resin composition, it is preferably 3 nm or more, more preferably 10 nm or more, and still more preferably 20 nm. From the viewpoint of improving the handleability of the modified cellulose and the dimensional stability of the resin composition, it is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, and even more preferably 120 nm or less. .

[substituent]
The substituent is composed of a substituent represented by the following formula (1), a substituent represented by (2), and a substituent represented by (3) from the viewpoint of heat resistance and dispersibility in a resin. One or more selected from the group.
-R ¹ (1)
—CH ₂ —CH(OH)—CH ₃ (2)
_-CH2 -CH(OH) _-CH2 - _CH3 (3)
[Wherein, R ¹ in general formula (1) represents a linear or branched alkyl group having 3 or 4 carbon atoms]
From the viewpoint of heat resistance and dispersibility in a resin, the substituent is preferably one selected from the group consisting of a substituent represented by general formula (2) and a substituent represented by (3). above, and more preferably a substituent represented by general formula (3).

In modified cellulose, such substituents are each independently bound to cellulose via ether linkages. Therefore, the modified cellulose in the present invention is exemplified by modified cellulose represented by the following general formula.

[Wherein, R is the same or different and is selected from the group consisting of hydrogen or a substituent represented by the above formula (1), a substituent represented by (2) and a substituent represented by (3) and m represents an integer of 20 or more and 3000 or less. However, in the formula, at least one R is any of the substituents described above. ]

The modified cellulose represented by the general formula has a repeating structure of cellulose units into which the substituents have been introduced. As the repeating number of the repeating structure, m in the general formula may be an integer of 20 or more and 3000 or less, preferably 100 or more, and 200 500 or more is more preferable, and from the same viewpoint, 2000 or less is preferable, 1000 or less is more preferable, and 800 or less is even more preferable.

[Molar degree of substitution (MS)]
In the modified cellulose, the molar amount (molar substitution degree: MS) in which the substituent is introduced with respect to 1 mol of the anhydroglucose unit of the cellulose cannot be unconditionally limited depending on the type of the substituent, but the affinity between the modified cellulose and the resin It is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.2 or more, and still more preferably 0.4 or more from the viewpoint of ensuring the rigidity of the molded article. Therefore, it is preferably 3 or less, more preferably 2 or less, still more preferably 1 or less, and still more preferably 0.8 or less. Here, when the bonded substituents are composed of a plurality of types of substituents, the MS of the bonded substituents is the sum of the MSs of the respective substituents. In addition, in this specification, the MS of the substituent in the modified cellulose can be measured according to the method described in Examples below.

[Crystallinity]
Modified cellulose having a cellulose type I crystal structure is preferred as the modified cellulose.
The crystallinity of the modified cellulose is preferably 10% or more, more preferably 15% or more, and still more preferably 20% or more, from the viewpoint of strength development of the molded article to be obtained. From the viewpoint of raw material availability, it is preferably 90% or less, more preferably 85% or less, still more preferably 80% or less, and even more preferably 75% or less. In this specification, the crystallinity of cellulose is the cellulose type I crystallinity calculated from the diffraction intensity value by the X-ray diffraction method, and can be measured according to the method described in Examples below. The cellulose type I is a crystalline form of natural cellulose, and the degree of cellulose type I crystallinity means the ratio of the amount of crystalline regions to the entire cellulose. The presence or absence of the cellulose type I crystal structure can be determined by the presence of a peak at 2θ=22.6° in the X-ray diffraction measurement described in Examples below.

[Method for producing modified cellulose]
In the modified cellulose of the present invention, as described above, the substituents are bonded to the cellulose via ether bonds, and the introduction of the substituents can be carried out according to known methods. For example, a cellulosic raw material may be reacted with a compound having a substituent (also referred to as an "etherifying agent") in the presence of a base.

[Cellulosic raw materials]
The cellulosic raw materials used in the present invention include woody (coniferous and broad-leaved trees), herbaceous (Poaceae, Malvaceae, and Leguminosae plant materials, Palmaceae non-woody materials), pulps (cotton seeds). cotton linter pulp obtained from the surrounding fibers), papers (newspaper, cardboard, magazines, high-quality paper, etc.), and the like. Of these, woody plants and herbaceous plants are preferred from the viewpoint of availability and cost reduction.

Although the average fiber diameter of the cellulosic raw material is not particularly limited, it is preferably 5 μm or more, more preferably 7 μm or more, and still more preferably 15 μm from the viewpoint of easy availability of the cellulosic raw material and cost reduction. It is preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and even more preferably 30 μm or less.

In addition, from the viewpoint of reducing the number of manufacturing steps, a cellulose-based raw material that has been pulverized in advance may be used. In that case, the average fiber diameter is preferably 1 nm or more, more preferably 1 nm or more, from the viewpoint of improving the heat resistance of the resin composition. is 2 nm or more. Although the upper limit is not particularly set, it is preferably 500 nm or less, more preferably 300 nm or less, from the viewpoint of improving the handleability of the cellulosic raw material.

The average fiber diameter of the cellulosic raw material can be measured in the same manner as for the modified cellulose described above.

[base]
The base functions as a catalyst for advancing the etherification reaction or as a reaction activator for the cellulosic raw material.

The base used in the present invention is not particularly limited, but from the viewpoint of promoting the etherification reaction, alkali metal hydroxides, alkaline earth metal hydroxides, primary to tertiary amines, quaternary ammonium salts, imidazoles. and derivatives thereof, pyridine and its derivatives, and alkoxides are preferred, and one or more selected from alkali metal hydroxides and alkali earth metal hydroxides are More preferably, one or more selected from alkali metal hydroxides is even more preferable.

Alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like.

The amount of the base to be mixed cannot be unconditionally determined depending on the type of the base used and the type of the etherifying agent, but from the viewpoint of advancing the etherification reaction with respect to the anhydroglucose unit of the cellulosic raw material, it is preferably 0.01. equivalent or more, more preferably 0.1 equivalent or more, still more preferably 0.2 equivalent or more, and from the viewpoint of suppressing the production cost of modified cellulose, preferably 10 equivalent or less, more preferably 1 equivalent or less, still more preferably is 0.5 equivalents or less, more preferably 0.3 equivalents or less. Anhydroglucose unit is abbreviated as "AGU". AGU is calculated assuming that the cellulosic feedstock is composed entirely of anhydroglucose units.

The cellulosic raw material and the base may be mixed in the presence of a solvent. Examples of solvents include water, isopropanol, t-butanol, dimethylformamide, toluene, methyl isobutyl ketone, acetonitrile, dimethyl sulfoxide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, hexane, 1,4-dioxane. , and mixtures thereof.

[Etherification agent]
As the etherifying agent, when the modified cellulose is reacted with the cellulosic raw material, the substituent represented by the above formula (1), the substituent represented by (2) and the substituent represented by (3) Although there is no particular limitation as long as one or more substituents selected from the group consisting of groups can be introduced into cellulose, from the viewpoint of ensuring reactivity with cellulosic raw materials, reactive cyclic One or more selected from the group consisting of a compound having a structural group and an organic halogen compound is preferred, and one or more selected from the group consisting of a compound having an epoxy group and a halogenated hydrocarbon group is more preferred, and the epoxy group is more preferably one or more selected from the group consisting of compounds having

The etherifying agent for introducing the substituent represented by formula (2) is an alkylene oxide compound represented by the following formula (2A) (ie, propylene oxide).

The etherification agent for introducing the substituent represented by formula (3) is an alkylene oxide compound (ie, butylene oxide) represented by the following formula (3A).

The amount of the etherifying agent to be added cannot be generally determined depending on the desired degree of introduction of substituents into the resulting modified cellulose and the structure of the etherifying agent used, but from the viewpoint of improving the reactivity with the cellulosic raw material. The amount of such compounds is preferably 0.01 equivalents or more, more preferably 0.1 equivalents or more, still more preferably 0.3 equivalents or more, and still more preferably It is 0.5 equivalents or more, more preferably 1.0 equivalents or more. On the other hand, it is preferably 10 equivalents or less, more preferably 8 equivalents or less, even more preferably 6.5 equivalents or less, still more preferably 5 equivalents or less, from the viewpoint of suppressing the production cost of modified cellulose.

[Etherification reaction]
The etherification reaction between the compound and the cellulosic raw material can be carried out, for example, by mixing the two in the presence of a solvent.

As the solvent, a solvent that can be used when the cellulosic raw material and the base are mixed can be used.
The amount of the solvent to be used is not generally determined by the type of the cellulosic raw material and the etherifying agent, but it is from the viewpoint of improving the reactivity between the etherifying agent and the cellulosic raw material with respect to 100 parts by mass of the cellulosic raw material. Therefore, it is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, still more preferably 80 parts by mass or more, and still more preferably 90 parts by mass or more. 000 parts by mass or less, more preferably 1,000 parts by mass or less, still more preferably 200 parts by mass or less, and even more preferably 100 parts by mass or less.

Mixing conditions are not particularly limited as long as the cellulosic raw material and the etherifying agent are uniformly mixed and the reaction can proceed sufficiently, and continuous mixing may or may not be performed. When using a relatively large reaction vessel exceeding 1 L, stirring may be performed as appropriate from the viewpoint of controlling the reaction temperature.

The reaction temperature is not unconditionally determined depending on the types of the cellulosic raw material and the etherifying agent and the target introduction rate, but from the viewpoint of improving the reactivity between the etherifying agent and the cellulosic raw material, it is preferably 25°C. above, more preferably 30°C or higher, still more preferably 35°C or higher, still more preferably 40°C or higher, still more preferably 45°C or higher, and from the viewpoint of suppressing thermal decomposition of the modified cellulose, preferably 120°C or lower, It is more preferably 100° C. or lower, still more preferably 80° C. or lower, still more preferably 70° C. or lower, still more preferably 60° C. or lower, still more preferably 55° C. or lower.

The reaction time is not unconditionally determined depending on the types of the cellulosic raw material and the etherifying agent and the target introduction ratio, but from the viewpoint of improving the reaction rate between the etherifying agent and the cellulosic raw material, the reaction time is preferably 0.5 hours. 1 hour or more, more preferably 0.5 hours or more, still more preferably 1 hour or more, and from the viewpoint of improving the productivity of the modified cellulose, preferably 60 hours or less, more preferably 10 hours or less, and even more preferably 5 hours or less, more preferably 3 hours or less.

Further, after the reaction, the modified cellulose may be pulverized by performing a known pulverization treatment. Alternatively, a finely modified cellulose can be obtained by carrying out the introduction reaction of the substituent described above using a cellulosic raw material which has been subjected to fineness treatment in advance.

After the reaction, an appropriate post-treatment can be carried out in order to remove unreacted compounds, bases and the like. As a post-treatment method, for example, an unreacted base can be neutralized with an acid (organic acid, inorganic acid, etc.), and then washed with a solvent in which the unreacted compound or base dissolves. If desired, further drying (such as vacuum drying) may be performed.

In the modified cellulose obtained, 1 It is a state in which at least one kind of substituent is ether-bonded. Specifically, for example, modified cellulose represented by the above general formula is exemplified.

<Resin composition>
The resin composition of the present invention gives a molded article obtained by molding it with high rigidity and suppressed coloring. The rigidity of the molded article can be evaluated, for example, by the method described in Examples below, and the degree of suppression of coloration of the molded article can be evaluated, for example, by the method described in Examples below. .

Although the amount of each component in the resin composition of the present invention depends on the type of resin, it is as follows.

From the viewpoint of producing a molded article, the amount of the polypropylene resin blended in the resin composition of the present invention is preferably 20% by mass or more, more preferably 30% by mass or more, still more preferably 40% by mass or more, and still more preferably 50% by mass. % by mass or more, more preferably 60% by mass or more, preferably 99.5% by mass or less, more preferably 99% by mass or less, even more preferably 90% by mass or less, still more preferably from the viewpoint of blending the modified cellulose. is 80% by mass or less.

The amount of modified cellulose in the resin composition of the present invention is preferably 0.5% by mass or more, more preferably 1% by mass or more, from the viewpoint of improving the elastic modulus and strength of the resulting resin composition. It is preferably 10% by mass or more, more preferably 20% by mass or more, and from the viewpoint of the strength of the resulting resin composition, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. , more preferably 40% by mass or less.

The amount of the modified cellulose in the resin composition of the present invention is preferably 1 part by mass or more, more preferably 1 part by mass or more, based on 100 parts by mass of the polypropylene resin, from the viewpoint of improving the elastic modulus and strength of the resulting resin composition. is 10 parts by mass or more, more preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and from the viewpoint of the strength of the resin composition obtained, preferably 200 parts by mass or less, more preferably 100 parts by mass Below, more preferably 70 parts by mass or less, more preferably 50 parts by mass or less.

Molded articles obtained by molding the resin composition of the present invention are used, for example, in fields such as electronics, aerospace, civil engineering and construction, automobiles, and vehicle applications, such as resin molding materials, electrical insulating materials, paints, inks, and coating agents. It can be preferably used as.

[Compatibilizer]
In the resin composition of the present invention and the method for producing the resin composition of the present invention, it is preferable to further incorporate a compatibilizer. By using a compatibilizer, the interface between the polypropylene resin and the modified cellulose is strengthened and the dispersibility of the modified cellulose is improved, thereby exhibiting the effect of improving the elastic modulus and strength.

Examples of the compatibilizing agent include those containing one or more selected from the group consisting of (A) a compound having an acid anhydride group and (B) a silane coupling agent.

The acid anhydride group in the compound (A) is not particularly limited, and examples thereof include those derived from maleic anhydride, succinic anhydride, glutaric anhydride and the like.

Examples of compounds in the compound (A) include polyolefin-based, acrylic, and styrene-based polymer compounds, and polyolefin-based polymer compounds are preferable from the viewpoint of ensuring affinity with the resin to be blended.

Examples of polyolefin-based polymers include ethylene-based polymers [high-density polyethylene, medium-density polyethylene, low-density polyethylene, ethylene and one or more other vinyl compounds (e.g., α-olefin, vinyl acetate, methacrylic acid, acrylic acid, etc.). )], propylene polymers [polypropylene, copolymers of propylene and one or more other vinyl compounds, etc.], ethylene propylene copolymers, polybutene and poly-4-methylpentene-1 etc. are exemplified, but propylene-based polymers are preferred.

Specific examples of the (A) compound include, for example, maleic anhydride-modified polyolefin, and more specifically, maleic anhydride-modified polypropylene.

(A) compound may be prepared according to a known method, or a commercially available product may be used. Suitable commercially available products include, for example, "Umex" (polypropylene having a maleic anhydride group) manufactured by Sanyo Chemical Industries, Ltd. "OREVAC G" (polypropylene having a maleic anhydride group) manufactured by Arkema, " Bondine" (ethylene/acrylic acid/maleic anhydride terpolymer) and the like are exemplified.

(A) The weight average molecular weight (Mw) of the compound is preferably 1,000 or more, more preferably 5,000 or more, and still more preferably 10,000 or more, from the viewpoint of ensuring affinity with the modified cellulose. . In addition, from the viewpoint of expressing physical properties due to entanglement with the polypropylene resin, it is preferably 150,000 or less, more preferably 140,000 or less, and even more preferably 100,000 or less.

In addition, the compound (A) has a melting point of preferably 250° C. or less, more preferably 200° C. or less, and still more preferably 150° C. or less from the viewpoint of suppressing deterioration of the modified cellulose when composited with a resin. preferable. The lower limit is not particularly limited, and is about 100° C., for example.

From the viewpoint of improving the elastic modulus and strength of the resin composition, the amount of the compatibilizer compounded in the resin composition is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass, with respect to 100 parts by mass of the polypropylene resin. It is at least 1 part by mass, more preferably at least 1 part by mass, and from the same viewpoint, preferably at most 10 parts by mass, more preferably at most 5 parts by mass, and even more preferably at most 2 parts by mass.

In addition, from the viewpoint of improving the elastic modulus and strength of the resin composition, the amount of the compatibilizer compounded in the resin composition is preferably 1 part by mass or more, more preferably 3 parts by mass, with respect to 100 parts by mass of the modified cellulose. parts or more, more preferably 5 parts by mass or more. On the other hand, from the viewpoint of cost effectiveness, the amount of the compatibilizer in the resin composition is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and still more preferably 10 parts by mass with respect to 100 parts by mass of the modified cellulose. It is below the department.

The resin composition of the present invention includes, as components other than the above, a plasticizer; a crystal nucleating agent; a filler (inorganic filler, organic filler); a hydrolysis inhibitor; a flame retardant; Lubricants such as waxes and anionic surfactants; ultraviolet absorbers; antistatic agents; antifogging agents; light stabilizers; pigments; Polysaccharides; Natural proteins such as gelatin, glue, and casein; Inorganic compounds such as tannin, zeolite, ceramics, and metal powder; It can be blended within a range that does not impair the effects of the present invention. Similarly, other polymer materials and other resin compositions can be added within a range that does not impair the effects of the present invention. The blending ratio of such optional components may be appropriately blended as long as the effects of the present invention are not impaired. It is more preferable that the content is about mass % or less.

[Method for producing resin composition]
The resin composition of the present invention comprises the above-mentioned polypropylene resin or modified cellulose to which a predetermined substituent is bonded, optionally together with a compatibilizer, solvent, curing agent, curing accelerator and/or other components. , a step of mixing with a high-pressure homogenizer or the like. Preferably, these raw materials are stirred with a Henschel mixer, a rotation-revolution stirrer, or melt-kneaded with a known kneader such as a closed kneader, a single-screw or twin-screw extruder, an open-roll kneader, or the like. The resin composition of the present invention can be produced by mixing under pressure.

Therefore, the method for producing a resin composition of the present invention comprises a polypropylene resin, a substituent represented by the above formula (1), a substituent represented by (2), and a substituent represented by (3). A step of mixing with modified cellulose in which one or more substituents selected from the group are each independently bonded to cellulose via an ether bond.

The amount of the modified cellulose added in the step of mixing the polypropylene resin and the modified cellulose is preferably 1 part by mass with respect to 100 parts by mass of the polypropylene resin, from the viewpoint of improving the elastic modulus and strength of the resulting resin composition. Above, more preferably 10 parts by mass or more, still more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, and from the same viewpoint, preferably 200 parts by mass or less, more preferably 100 parts by mass or less , more preferably 70 parts by mass or less, more preferably 50 parts by mass or less.

From the viewpoint of exhibiting the effect of improving the elastic modulus and strength, it is preferable to further add the compatibilizer in the step of mixing the polypropylene resin and the modified cellulose.

From the viewpoint of improving the elastic modulus and strength of the resin composition, the amount of the compatibilizer added to the resin composition is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass, based on 100 parts by mass of the polypropylene resin. It is at least 1 part by mass, more preferably at least 1 part by mass, and from the same viewpoint, preferably at most 10 parts by mass, more preferably at most 5 parts by mass, and even more preferably at most 2 parts by mass.

In addition, the amount of the compatibilizer added to the resin composition is preferably 1 part by mass or more, more preferably 3 parts by mass with respect to 100 parts by mass of the modified cellulose, from the viewpoint of improving the elastic modulus and strength of the resin composition. parts or more, more preferably 5 parts by mass or more, and from the same viewpoint, the amount of the compatibilizer in the resin composition is preferably 50 parts by mass or less, more preferably 50 parts by mass or less, with respect to 100 parts by mass of the modified cellulose. is 20 parts by mass or less, more preferably 10 parts by mass or less.

EXAMPLES The present invention will be specifically described below with reference to Production Examples, Examples, Comparative Examples and Test Examples. These examples and the like are merely illustrations of the present invention, and do not mean any limitation. Parts in the examples are parts by weight unless otherwise specified. "Atmospheric pressure" means 101.3 kPa, and "room temperature" means 25°C.

[Degree of Introduction of Substituents]
First, the content % (% by mass) of the substituent contained in the modified cellulose to be measured was determined according to Analytical Chemistry, Vol. 51, No. 13, 2172 (1979), the Zeisel method known as a method for analyzing the average number of added moles of alkoxy groups in cellulose ethers, as described in "The Japanese Pharmacopoeia 15th Edition (Section of analytical methods for hydroxypropyl cellulose)". Calculated according to The procedure is shown below.

(i) 0.1 g of n-tetradecane was added to a 200 mL volumetric flask, and the volume was increased to the marked line with hexane to prepare an internal standard solution.
(ii) 70 mg of the purified and dried modified cellulose and 80 mg of adipic acid to be measured were accurately weighed into a 10 mL vial, 2 mL of hydroiodic acid was added, and the vial was sealed.
(iii) The mixture in the vial was heated with a block heater at 160° C. for 1 hour while stirring with a stirrer tip.
(iv) After heating, 2 mL of the internal standard solution and 2 mL of diethyl ether were sequentially injected into the vial and stirred at room temperature for 1 minute.
(v) The upper layer (diethyl ether layer) of the mixture separated into two phases in the vial was analyzed by gas chromatography (manufactured by SHIMADZU, trade name: GC2010Plus).
(vi) Analysis was performed in the same manner as in (ii) to (v) except that the modified cellulose to be measured was changed to 5 mg, 10 mg, and 15 mg of the etherification agent used for the modification, and etherification was performed. A calibration curve for the agent was prepared.
(vii) Substituents contained in the modified cellulose to be measured were quantified from the prepared calibration curve and the analytical results of the modified cellulose to be measured. Analysis conditions are as follows.

Column: manufactured by Agilent Technologies, trade name: DB-5 (12 m, 0.2 mm × 0.33 μm)
Column temperature: 30°C (10min Hold) → 10°C/min → 300°C (10min Hold)
Injector temperature: 300°C
Detector temperature: 300°C
Injection amount: 1 μL
The content (% by mass) of the substituent contained in the modified cellulose to be measured was calculated from the detected amount of the etherifying agent used.

Next, from the obtained content of substituents, the molar substitution degree (MS) (molar amount of substituents per 1 mol of anhydroglucose unit) was calculated using the following formula (1).
Formula (1)
MS = (W/ _Mw )/((100-W)/162.14)
W: content of substituents introduced in the modified cellulose to be measured (% by mass)
M _w : Molecular weight of introduced etherifying agent (g/mol)

[Average fiber diameter of cellulosic raw material]
Deionized water was added to the object to be measured to prepare a dispersion having a content of 0.01% by mass. Using a wet dispersion type image analysis particle size distribution meter (manufactured by Jusco International Co., Ltd., trade name: IF-3200), the dispersion is measured using a front lens of 2x, a telecentric zoom lens of 1x, and an image resolution of 0.835 μm/pixel. , syringe inner diameter: 6515 μm, spacer thickness: 500 μm, image recognition mode: ghost, threshold: 8, analysis sample amount: 1 mL, sampling: 15%. 100 or more measurement objects were measured, and their average ISO fiber diameter was calculated as the average fiber diameter.

[Determination of presence/absence of diffraction peak at 2θ=18-23°]
The presence or absence of a diffraction peak at 2θ=18-23° of the modified cellulose in the present specification is determined using an X-ray diffractometer (trade name: RigakuRINT 2500VC X-RAY diffractometer manufactured by Rigaku Corporation) under the following conditions. It was determined by measuring.
Measurement pellet preparation conditions: Smooth pellets with an area of 320 mm ² × thickness of 1 mm were prepared by applying pressure in the range of 10 to 20 MPa with a tableting machine.
X-ray diffraction analysis conditions: step angle 0.01°, scan speed 10°/min, measurement range: diffraction angle 2θ = 5 to 45°
X-ray source: Cu/Kα-radiation, tube voltage: 40 kv, tube current: 120 mA
Peak splitting conditions: After removing background noise, fitting was performed with a Gaussian function so that the error between 2θ=13-23° was within 5%.

[Confirmation of crystal structure]
The crystal structure of the modified cellulose was confirmed by measurement under the above conditions using the above diffractometer.
The crystallinity of the cellulose type I crystal structure was calculated based on the following formula (A) using the areas of the X-ray diffraction peaks obtained by the above peak division.
Cellulose type I crystallinity (%) = [I _cr /(I _cr + I _am )] × 100 (A
)
[Wherein, I _cr is the area of the diffraction peak of the lattice plane (002 plane) (diffraction angle 2θ=22-23°) in X-ray diffraction, and I _am is the amorphous part (diffraction angle 2θ=18.5°). Areas of diffraction peaks are shown. ]

Production Example 1 of Modified Cellulose <Cellulose with Butylene Oxide>
Bleached coniferous kraft pulp (hereinafter abbreviated as NBKP, manufactured by West Fraser, trade name: Hinton, fibrous, average fiber diameter 24 μm, cellulose content 90% by mass, water content 5% by mass) as a cellulose-based raw material Using. First, 1.5 g of a 6.4% by mass sodium hydroxide aqueous solution (NaOH 0.26 equivalent/AGU) was added to 1.5 g of absolutely dried NBKP and mixed uniformly, and then 1.00 g of butylene oxide as an etherification agent. (1.5 equivalents/AGU) was added, and after sealing, the reaction was allowed to stand at 50° C. for 2 hours. After the reaction, neutralize with acetic acid, thoroughly wash with water and acetone to remove impurities, and vacuum-dry overnight at 70° C. to obtain modified cellulose 1 (having a substituent of formula (3)). MS 0.2) of butylene oxide was obtained.

Production Example 2 of Modified Cellulose <Cellulose with Butylene Oxide>
Modified cellulose 2 having a substituent of formula (3) (oxidized MS 0.6) of butylene was obtained.

Production Example 3 of Modified Cellulose <Cellulose with Butylene Oxide>
Modified cellulose 3 having a substituent of formula (3) (oxidized MS 0.8) of butylene was obtained.

Production Example 4 of Modified Cellulose <Cellulose with Propylene Oxide>
Formula (2 ) substituent was obtained (MS 0.2 for propylene oxide).

Examples 1 to 9 and Comparative Examples 1 to 3 <resin composition>
The composition raw materials shown in Table 1, that is, the polypropylene resin, the modified cellulose obtained in Production Examples 1 to 4, and optionally the compatibilizer are combined as shown in Table 1, and a melt kneader (Japan Steel Works, Ltd.) (trade name: TEX28V (screw diameter: 28 mm, L/D = 42) manufactured by Sanyo Denki), the resin composition was melt-kneaded at a discharge rate of 10 kg/h, a number of revolutions of 200 rpm, and 180°C to obtain a resin composition. The obtained pellets of the resin composition were dehumidified and dried at 110° C. for 2 hours or more so that the water content was 500 ppm or less.

<Molded body>
The obtained resin composition was injection molded using an injection molding machine (trade name: J110AD-180H, manufactured by Japan Steel Works, Ltd., cylinder temperature setting at 6 points). The cylinder temperature was set to 200° C. for the fifth unit from the tip of the nozzle, 190° C. for the remaining one unit, and 45° C. below the hopper. The mold temperature was set to 80° C., and a prismatic test piece (125 mm×13 mm×6.4 mm) was molded to obtain a molding of the resin composition.

Details of raw materials and abbreviations in Table 1 are as follows.
<Resin>
PP: polypropylene resin, manufactured by Prime Polymer, trade name: J106G
<Compatibilizer>
Yumex 1001: manufactured by Sanyo Chemical Industries, maleic anhydride-modified polypropylene, weight average molecular weight 45,000, melting point 142°C

<Etherification agent for modified cellulose>
BO: butylene oxide PO: propylene oxide

Test Example 1 <Measurement of bending elastic modulus and bending strength>
The flexural modulus of each molded body of the resin composition of each example and comparative example was measured as follows. For the prismatic test piece, a bending test is performed with a crosshead speed of 3 mm / min using a Tensilon (Tensilon universal tester RTC-1210A manufactured by Orientec) based on ASTM D790, and the bending elastic modulus and Bending strength was determined.

Test Example 2 <Evaluation of coloring suppression>
For each molded article of the resin composition of each example and comparative example, the coloration suppression property was evaluated as follows. Specifically, the surface of the prismatic test piece was visually observed, and the coloring suppression property was evaluated according to the following evaluation criteria.

Evaluation Criteria Compared to modified cellulose or unmodified cellulose before melt kneading,
4: Almost no color change 3: Slightly yellowed 2: Yellowed 1: Browned

From Comparative Examples 1 and 3 and Examples 2 and 7, and Comparative Examples 1 and 2 and Examples 1 and 4 to 6, compared with examples using cellulose with no substituents (Comparative Examples 2 and 3) In the examples (Examples 2 and 7 and Examples 1, 4 to 6) using the prescribed modified cellulose, it was found that the flexural modulus, that is, the rigidity was greatly improved. Furthermore, no significant difference was observed in such effects even when the type of etherifying agent and the degree of molar substitution were different.

From Comparative Example 1 and Examples 1 to 3, and Comparative Example 1 and Examples 6 and 7, it was found that the flexural modulus improved as the amount of modified cellulose added increased.

From Examples 3 to 5, it was found that as the molar substitution value of the modified cellulose increased, the suppression of coloration increased while maintaining rigidity.
From Examples 1 and 8, and Examples 6 and 9, it was found that the flexural modulus and flexural strength were improved by adding a compatibilizer.

INDUSTRIAL APPLICABILITY The resin composition of the present invention can be suitably used for various industrial applications such as daily commodities, home appliance parts, automobile parts and the like.

Claims (9)

Polypropylene resin, and one or more substituents selected from the group consisting of a substituent represented by the following formula (1), a substituent represented by (2) and a substituent represented by (3), A resin composition containing modified cellulose having a cellulose type I crystal structure, each of which is independently bound to cellulose via an ether bond.
-R ¹ (1)
—CH ₂ —CH(OH)—CH ₃ (2)
_-CH2 -CH(OH) _-CH2 - _CH3 (3)
[Wherein, R ¹ in general formula (1) represents a linear or branched alkyl group having 3 or 4 carbon atoms] 2. The resin composition according to claim 1, further comprising a compatibilizer. The resin composition according to claim 1 or 2, wherein 1 part by mass or more and 200 parts by mass or less of the modified cellulose is blended with 100 parts by mass of the polypropylene resin. 4. The resin composition according to claim 2, wherein 1 part by mass or more and 50 parts by mass or less of said compatibilizing agent is blended with 100 parts by mass of said modified cellulose. 5. The resin composition according to any one of claims 1 to 4, wherein the content of the polypropylene resin in the resin composition is 20% by mass or more and 99.5% by mass or less. The resin composition according to any one of claims 2 to 5, wherein the compatibilizer contains one or more selected from the group consisting of (A) and (B) below.
(A) a compound having an acid anhydride group (B) a silane coupling agent Polypropylene resin, and one or more substituents selected from the group consisting of a substituent represented by the following formula (1), a substituent represented by (2) and a substituent represented by (3), A method for producing a resin composition, comprising a step of mixing modified cellulose having a cellulose type I crystal structure, each independently bonded to cellulose via an ether bond.
-R ¹ (1)
—CH ₂ —CH(OH)—CH ₃ (2)
_-CH2 -CH(OH) _-CH2 - _CH3 (3)
[Wherein, R ¹ in general formula (1) represents a linear or branched alkyl group having 3 or 4 carbon atoms] The resin composition according to claim 7, wherein in the step of mixing the polypropylene resin and the modified cellulose, a compatibilizer is further added in an amount of 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the modified cellulose. A method of making things. The method for producing a resin composition according to claim 8, wherein the compatibilizer contains one or more selected from the group consisting of (A) and (B) below.
(A) a compound having an acid anhydride group (B) a silane coupling agent