Resin composition and pellets

Abstract

Provided are a novel resin composition that contains regenerated cellulose fibers and makes it possible to obtain more environmentally friendly molded articles having good mechanical properties, and pellets thereof.　The resin composition contains a thermoplastic resin (A) and regenerated cellulose fibers (B) which are CS2-free regenerated cellulose fibers having a monofilament tensile elongation at break measured according to JIS L1015 of 10% or more and a toughness of 35 MPa or more.

Description

Resin composition and pellets

[0001] The present invention relates to a resin composition and a pellet.

[0002] Toward building a sustainable society, the use of composite resin compositions that blend petroleum-derived resin components with biomass materials is increasing. Among these composite resin compositions, research is underway on composite resin compositions that blend plant fibers, such as regenerated cellulose fibers, with thermoplastic resins. For example, Patent Documents 1 and 2 propose fiber-reinforced resin compositions that combine regenerated cellulose fibers (viscose rayon) obtained by the viscose process with polypropylene resin. In such fiber-reinforced resin compositions, the inclusion of biomass materials is expected to improve mechanical properties such as tensile strength and impact strength.

[0003] JP 2016-020465 A JP 2018-187944 A

[0004] Because cellulose is very insoluble in solvents, most regenerated cellulose fibers are produced through a long and complicated process. For example, viscose rayon is produced by immersing cellulose in a sodium hydroxide solution to produce alkali cellulose, which is then mixed with carbon disulfide (CS). ２ Viscose rayon is produced by reacting cellulose xanthate with carbon disulfide (CS), which is a major environmental burden, and then coagulating and regenerating the dilute alkaline solution (viscose) of the cellulose xanthate. ２ ) was used, and the resulting viscose rayon contained CS ２ However, trace amounts of cellulose remain, so there are studies being conducted to replace it with regenerated cellulose fibers that are produced using simpler processes and with less environmental impact.

[0005] By the way, regenerated cellulose fibers made using the "solvent method" do not chemically modify the cellulose, so CO ２It has been attracting attention as a biomass material with low emissions and a lower environmental impact. However, according to the investigations of the present inventors, it has been found that resin compositions containing conventional solvent-process regenerated cellulose fibers are inferior to resin compositions containing viscose rayon in terms of mechanical properties, particularly Charpy impact strength, of molded articles.

[0006] An object of the present disclosure is to provide a novel resin composition containing regenerated cellulose fibers, which has a lower environmental impact and can produce molded articles with good mechanical properties, and pellets thereof.

[0007] As a result of extensive investigation, the present inventors have found that a thermoplastic resin (A) and a CS ２ The present inventors have found that the above-mentioned problems can be solved by a resin composition containing regenerated cellulose fiber (B), which is a regenerated cellulose fiber that does not contain (A), and which has a monofilament tensile breaking elongation of 10% or more measured in accordance with JIS L 1015 and a toughness of 35 MPa or more.

[0008] According to the present disclosure, it is possible to provide a novel resin composition containing regenerated cellulose fibers, which has a lower environmental impact and can produce molded articles having good mechanical properties, and pellets thereof.

[0009] 1 is a photograph showing an example of a molded article made of a resin composition of Comparative Example 3 containing viscose rayon and a molded article made of a resin composition of Example 1.

[0010] An embodiment of the present disclosure will be described in detail below. However, the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Furthermore, when multiple upper and lower limits are described for a particular parameter, any of these upper and lower limits can be combined to form a suitable numerical range. Furthermore, the lower and / or upper limits of a numerical range described in this disclosure may be replaced with numerical values ​​within that range and shown in the examples. The expression "X to Y" indicating a numerical range means "X or greater and Y or less." Furthermore, unless otherwise noted, all test temperatures are room temperature (20°C ± 5°C). If a specific description described for one embodiment also applies to other embodiments, that description may be omitted in other embodiments.

[0011] The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate without departing from the spirit of the present disclosure. The present disclosure is not limited by the embodiments, but is limited only by the claims. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0012] In this specification, "regenerated cellulose fiber" refers to a fiber obtained by dissolving raw cellulose and regenerating it. Furthermore, in this disclosure, a "monofilament" refers to a single filament constituting a regenerated cellulose fiber, which is a single filament obtained by spinning from a single nozzle, or a single filament extracted from a multifilament obtained from a multi-hole nozzle. A "multifilament" refers to a bundle or aggregate of two or more monofilaments.

[0013] [Resin Composition] The first embodiment of the present disclosure relates to a resin composition. The resin composition according to the first embodiment comprises a thermoplastic resin (A) and a CS. ２and (B) a regenerated cellulose fiber not containing (A), wherein the monofilament has a tensile breaking elongation of 10% or more and a toughness of 35 MPa or more as measured in accordance with JIS L 1015. The resin composition according to the first embodiment can provide a molded article that has a lower environmental impact and good mechanical properties.

[0014] <Thermoplastic Resin (A)> The resin composition according to the first embodiment contains a thermoplastic resin (A) (hereinafter, sometimes referred to as "resin (A)"). A resin composition containing the resin (A) and the regenerated cellulose fibers (B) described below can produce a molded article having good mechanical properties. In particular, a molded article having excellent Charpy impact strength can be easily obtained. The resin (A) contained in the resin composition according to the first embodiment is not particularly limited as long as it exhibits the effects of the present disclosure when combined with the regenerated cellulose fibers (B). In a preferred embodiment, from the viewpoint of easily producing a molded article having good mechanical properties and easily suppressing discoloration of the molded article described below, the resin contains one or more thermoplastic resins selected from the group consisting of crystalline resins (a1) having a melting point of 250°C or less and amorphous resins (a2) having a glass transition temperature of 150°C or less. Preferred examples of the crystalline resin (a1) having a melting point of 250°C or less and the amorphous resin (a2) having a glass transition temperature of 150°C or less will be described below.

[0015] (Crystalline Resin (a1)) The crystalline resin (a1) (hereinafter sometimes referred to as "resin (a1)") having a melting point of 250°C or less is not particularly limited, and examples thereof include polyolefin-based resins, vinyl alcohol-based resins, vinyl ester-based resins, polyester-based resins, polyamide-based resins, polyacetal-based resins, etc. Examples of resin (a1) also include thermoplastic elastomers, biodegradable resins, biomass resins, etc. The melting point of resin (a1) is a value obtained by DSC measurement (DSC measurement is performed under conditions of a heating rate of 20°C / min and a heating rate of 10°C / min, and the melting peak temperature of the second scan is taken as the melting point).

[0016] Examples of polyolefin resins include homopolymers or copolymers of olefins having 2 to 6 carbon atoms [ethylene resins such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), low-density linear polyethylene (LLDPE), and ethylene-propylene copolymers; propylene resins such as polypropylene and propylene-butene copolymers; butene resins such as poly-1-butene and polyisobutylene; poly(methylpentene-1); propylene-methylpentene copolymers; ethylene-propylene-diene terpolymers (those containing 10% by mass or less of a diene component as a raw material); polymethylpentene, etc.]; copolymers of olefins having 2 to 6 carbon atoms and copolymerizable monomers [ethylene or propylene copolymers]; Examples of the copolymer include copolymers (random, block, and / or graft copolymers) of propylene (50 mol% or more) with vinyl acetate, alkyl (meth)acrylate, and / or aromatic vinyl compounds; homopolymers or copolymers of cyclic olefins (particularly cyclic olefins condensed with hydrocarbon rings, bridged cyclic olefins, etc.) optionally having substituents such as alkyl groups or ester groups (e.g., homopolymers of cyclic olefins such as polybicyclopentadiene and polynorbornene; copolymers of cyclic olefins selected from bicycloalkadienes, tricycloalkadienes, bicycloalkenes, and tricycloalkenes with α-olefins having 2 to 4 carbon atoms (e.g., ethylene)). These may be used alone or in combination of two or more. When a polypropylene resin is contained, the polypropylene resin may contain an acid-modified polypropylene resin (preferably, maleic anhydride-modified polypropylene resin and / or maleic acid-modified polypropylene resin).

[0017] Examples of vinyl alcohol resins include polyvinyl alcohol, ethylene-vinyl alcohol copolymers, etc. These may be used alone or in combination of two or more.

[0018] Examples of vinyl ester resins (carboxylic acid vinyl ester resins) include polyvinyl acetate, ethylene-vinyl acetate copolymers, etc. These may be used alone or in combination of two or more.

[0019] Examples of polyester-based resins include homopolyesters or copolyesters (e.g., copolyesters having a copolymerization component of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms such as adipic acid, an asymmetric aromatic dicarboxylic acid such as phthalic acid or isophthalic acid, and an alkylene glycol having 2 to 6 carbon atoms, polyoxyalkylene glycol, bisphenol A, etc.) containing alkylene terephthalate (ethylene terephthalate, butylene terephthalate, etc.) or alkylene naphthalate (ethylene naphthalate, butylene naphthalate, etc.) as repeating units; liquid crystalline polyesters having a melting point of 250°C or less; and homopolyesters or copolymers of lactones (e.g., ε-caprolactone). These may be used alone or in combination of two or more.

[0020] Examples of polyamide-based resins include aliphatic polyamides (such as nylon 6, nylon 610, nylon 612, nylon 11, and nylon 12); aromatic polyamides having a melting point of 250°C or less [such as polyamides obtained by reacting an aromatic dicarboxylic acid (such as terephthalic acid) with an aliphatic diamine (such as hexamethylenediamine); polyamides obtained by reacting an aliphatic dicarboxylic acid (such as adipic acid) with an aromatic diamine (such as metaxylylenediamine or paraxylylenediamine)]; and homopolymers or copolymers of lactams (such as ε-caprolactam). These may be used alone or in combination of two or more. Furthermore, the polyamide-based resin is not limited to homopolyamides and may also be copolyamides.

[0021] Examples of polyacetal resins include polyacetal (polyoxymethylene) and copolyacetal (trioxane-ethylene oxide copolymer, trioxane-1,3-dioxolane copolymer, etc.). These may be used alone or in combination of two or more.

[0022] Examples of the thermoplastic elastomer include polyolefin-based thermoplastic elastomers, polybutadiene-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, etc. These may be used alone or in combination of two or more.

[0023] Examples of biodegradable resins include one or more selected from cellulose esters, starch polyesters, polylactic acid (PLA), polyhydroxyalkanoates (PHAs) such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), polylactic acid / polycaprolactone copolymers, polyglycolic acid (PGA), polylactic acid / polyether copolymers, butanediol / long-chain dicarboxylic acid copolymers, polybutylene adipate / terephthalate (PBAT), polytetramethylene adipate-co-terephthalate, polyethylene terephthalate succinate (PETS), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and polyvinyl alcohol (PVA).

[0024] Biomass resins are partially or entirely made from bio-derived raw materials, and examples thereof include bio-PE, bio-polyamide 11, bio-polyamide 1010, aromatic polyester containing bio-derived resin, bio-polyurethane, bio-polycarbonate, bio-MXD10, 1012, 610, 510, 410, 56, 11T, bio-PET, bio-PTT, etc. These may be used alone or in combination of two or more.

[0025] As the resin (a1), the above-mentioned thermoplastic resins may be used alone or in combination of two or more.

[0026] (Amorphous Resin (a2)) The amorphous resin (a2) (hereinafter sometimes referred to as "resin (a2)") having a glass transition temperature of 150°C or less is not particularly limited, and examples thereof include vinyl chloride resins, styrene resins, and (meth)acrylic resins. Resin (a2) also includes thermoplastic elastomers, biodegradable resins, and biomass resins. The glass transition temperature of resin (a2) is a value measured in accordance with JIS K 7121 (measurement conditions: temperature rise rate: 20°C / min, and the glass transition temperature at the midpoint of the first scan is taken as the glass transition temperature).

[0027] Examples of vinyl chloride resins include polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, etc. These may be used alone or in combination of two or more.

[0028] Examples of styrene-based resins include polystyrene, styrene-α-methylstyrene copolymer, styrene-(meth)acrylic acid ester copolymer, styrene-maleic anhydride copolymer, etc. These may be used alone or in combination of two or more.

[0029] Examples of (meth)acrylic resins include poly(meth)acrylic acid esters such as polymethyl(meth)acrylate, methyl methacrylate-(meth)acrylic acid copolymers, methyl methacrylate-(meth)acrylic acid ester copolymers, methyl methacrylate-(meth)acrylic acid ester-(meth)acrylic acid copolymers, (meth)acrylic acid ester-styrene copolymers (MS resins, etc.), etc. These may be used alone or in combination of two or more.

[0030] Examples of amorphous thermoplastic elastomers, biodegradable resins, and biomass resins having a glass transition temperature of 150° C. or less include cellulose ester resins such as cellulose acetate resins. These may be used alone or in combination of two or more.

[0031] As the resin (a2), the above-mentioned thermoplastic resins may be used alone or in combination of two or more.

[0032] In one embodiment, the thermoplastic resin (A) preferably includes a resin (a1), and more preferably includes one or more resins (a1) selected from polyolefin resins, polyamide resins, and polyacetal resins. The melt flow rate (230°C, 2.16 kg load) of the thermoplastic resin (A), measured in accordance with ISO 1133, is preferably 10 to 180 g / 10 min.

[0033] In a preferred embodiment, the polyolefin resin preferably includes at least one selected from homopolymers or copolymers of olefins having 2 to 6 carbon atoms and copolymers of olefins having 2 to 6 carbon atoms and copolymerizable monomers. More specific examples include polypropylene, high-density polyethylene (HDPE), low-density polyethylene (LDPE), low-density linear polyethylene (LLDPE), poly-1-butene, polyisobutylene, copolymers of ethylene and propylene, ethylene-propylene-diene terpolymers (containing 10% by mass or less of a diene component as a raw material), polymethylpentene, random, block, and / or graft copolymers of ethylene or propylene (50% by mole or more) with other copolymerizable monomers (such as vinyl acetate, (meth)acrylic acid alkyl esters, and aromatic vinyl compounds). It is preferable to use one of these polyolefin resins alone or two or more of them in combination. Among these, polypropylene is particularly preferred from the viewpoints of mechanical strength and processability.

[0034] In one embodiment, when the thermoplastic resin (A) contains a polyolefin-based resin, it is preferable to use an acid-modified polyolefin in combination, from the viewpoint of improving the impregnation of the thermoplastic resin (A) into the regenerated cellulose fibers (B). As the acid-modified polyolefin, a maleic acid-modified polyolefin (preferably, maleic acid-modified polypropylene) or a maleic anhydride-modified polyolefin (preferably, maleic anhydride-modified polypropylene) is more preferable. Furthermore, in one embodiment, when a polyolefin-based resin and an acid-modified polyolefin are used in combination as the thermoplastic resin (A), it is more preferable to use the acid-modified polyolefin in combination so that the acid content in the thermoplastic resin (A) (the amount of acid components contained in the acid-modified polyolefin) is in the range of an average of 0.05 to 0.5 mass% in terms of maleic anhydride.

[0035] In a particularly preferred embodiment, the thermoplastic resin (A) comprises one or more resins (a1) selected from polypropylene, polyamide, and polyacetal (homopolymer and / or copolymer).

[0036] In one embodiment, the proportion of the thermoplastic resin (A) in the resin composition is preferably 30 to 95% by mass, more preferably 30 to 80% by mass, and even more preferably 30 to 75% by mass, based on the total mass of the resin composition. When the proportion of the thermoplastic resin (A) is within the above range, the proportion of the regenerated cellulose fiber (B) in the resin composition can be controlled, making it easier to obtain a molded product with good mechanical properties.

[0037] According to the studies of the present inventors, it has been surprisingly found that by combining a thermoplastic resin (A) (preferably one or more thermoplastic resins selected from the group consisting of a crystalline resin (a1) having a melting point of 250°C or less and an amorphous resin (a2) having a glass transition temperature of 150°C or less) with the regenerated cellulose fiber (B) described below, discoloration of the resulting molded article can be suppressed. As shown in FIG. 1 described below, the molded article of the resin composition of Comparative Example 3 containing viscose rayon is darkly colored. On the other hand, the molded article obtained from the resin composition according to the first embodiment has less discoloration than Comparative Example 3.

[0038] (Other Thermoplastic Resins) The resin composition according to the first embodiment may contain a thermoplastic resin (other thermoplastic resin) other than the thermoplastic resin (A) described above. The other thermoplastic resin may include, for example, a conventionally known crystalline resin having a melting point of more than 250°C and / or an amorphous resin having a glass transition temperature of more than 150°C. When the resin composition contains other thermoplastic resins, it is preferable that the amount of the other thermoplastic resins be 50% by mass or less relative to the total mass of the resin composition, from the viewpoint of moldability.

[0039] <Regenerated cellulose fibers (B)> The resin composition according to the first embodiment is a cellulose fiber (B) containing CS. ２The present invention also includes a regenerated cellulose fiber (B) (hereinafter sometimes referred to as "fiber (B)") that does not contain cellulose esters, and has a monofilament tensile breaking elongation of 10% or more and a toughness of 35 MPa or more, as measured in accordance with JIS L 1015. The tensile breaking elongation is a value measured for the regenerated cellulose fiber (B) under the conditions described below. The regenerated cellulose fiber (B) contained in the resin composition according to the first embodiment may be a monofilament, a multifilament, or a mixture thereof. The term "monofilament fiber (B)" in the resin composition refers to the fact that, when the resin composition is observed with various microscopes (e.g., scanning electron microscope (SEM) or optical microscope), the fiber (B) is dispersed in the form of a monofilament. The term "multifilament fiber (B)" in the resin composition refers to the fact that, when the resin composition is observed with various microscopes (e.g., scanning electron microscope (SEM) or optical microscope), the fiber (B) is observed as a bundle or aggregate of two or more monofilaments. The term "bundle of monofilaments" refers to a state in which a plurality of monofilaments are bundled together in one direction, and the term "aggregate of monofilaments" refers to a state in which a plurality of monofilaments are overlapped and aggregated.

[0040] The regenerated cellulose fiber (B) according to the first embodiment is "CS ２ The term "regenerated cellulose fiber not containing CS" means that the regenerated cellulose fiber (B) is ２ and / or C.S. ２ The term "substantially free" means that the above-mentioned components are not detected when the regenerated cellulose fiber (B) is analyzed by GC-MS. When the regenerated cellulose fiber (B) is prepared by a method other than the viscose method (preferably the solvent method), the fiber (B) is not considered to be "CS"-derived. ２ It can be said that it is a "regenerated cellulose fiber that does not contain cellulose."

[0041] Hereinafter, preferred embodiments of the regenerated cellulose fiber (B) will be described, but the aspects described as the physical properties of the "monofilament" can also be applied to the case where the fiber (B) is a multifilament. In other words, when the fiber (B) is a multifilament, it is preferable that the fiber (B) contains a monofilament having the physical properties.

[0042] "CS ２ As mentioned above, "regenerated cellulose fibers free of CS" can be prepared by methods other than the viscose method. ２ Since CS is used, the resulting fibers also contain ２ Therefore, CS tends to remain in the manufacturing process. ２ The use of regenerated cellulose fibers prepared by a method that does not use CS can contribute to reducing the environmental impact. On the other hand, resin compositions containing regenerated cellulose fibers prepared by a method other than the viscose method produce molded articles with poor mechanical properties. ２ We have discovered that by combining a novel regenerated cellulose fiber (B), which is a regenerated cellulose fiber free of cellulose esters and has a monofilament tensile breaking elongation of 10% or more and a toughness of 35 MPa or more as measured in accordance with JIS L 1015, with a thermoplastic resin (A), a resin composition can be obtained that achieves both reduced environmental impact and good mechanical properties of the molded article. Such regenerated cellulose fiber (B) can be easily obtained by employing a solvent method using an ionic liquid (preferably imidazolium ions) and setting a low draft ratio. A method for producing the regenerated cellulose fiber (B) will be described later.

[0043] Tensile Breaking Elongation The regenerated cellulose fiber (B) according to the first embodiment has a monofilament tensile breaking elongation of 10% or more, measured according to JIS L 1015. The tensile breaking elongation of the monofilament is preferably 10.5% or more, more preferably 11% or more, and even more preferably 11.5% or more. The upper limit of the tensile breaking elongation of the monofilament is not particularly limited, but from the viewpoint of easily controlling the tensile modulus of the monofilament, it is preferably 20% or less, more preferably 17% or less. In one embodiment, the tensile breaking elongation of the monofilament of fiber (B) may be 10 to 20%, or may be 10 to 17%. The tensile breaking elongation of the regenerated cellulose fiber (B) can be measured by the following method.

[0044] (Method for measuring tensile elongation at break of monofilament) The tensile elongation at break of the monofilament of fiber (B) is measured in accordance with JIS L 1015. Specifically, a single fiber is taken from the monofilament or the multifilament to be measured to form a monofilament, and then a tensile test is carried out under conditions of a temperature of 20°C and a relative humidity of 65% using an automatic single-fiber fineness measuring device and a strength and elongation measuring device (for example, manufactured by Lenzing Instruments / Austria, product names "Vibroskop Micro" and "Vibrodyn 500") at a chuck distance of 20 mm and a tensile speed of 20 mm / min. In this tensile test, the elongation at break of the monofilament is measured. The test is carried out 15 or more times, and the average value is calculated, and the value obtained by rounding off the first decimal place is used.

[0045] Toughness (tenacity) The toughness (tenacity) of the monofilament of fiber (B) according to the first embodiment is 35 MPa or more. By combining fiber (B) having a monofilament tensile breaking elongation of 10% or more and a toughness of 35 MPa or more with thermoplastic resin (A), the mechanical properties (particularly Charpy impact strength) of the molded article become good. In one embodiment, the toughness of the monofilament of fiber (B) is preferably 40 MPa or more, more preferably 45 MPa or more, and even more preferably 50 MPa or more. The toughness of the monofilament of fiber (B) can be measured under the following conditions.

[0046] (Method of measuring toughness of monofilament) A tensile test is carried out under the same conditions as for the tensile breaking elongation. Using the stress-strain curve (so-called SS curve) obtained by the tensile test, the toughness is calculated by determining the area enclosed by the curve from the origin to the breaking point. The area may be determined by analysis using analysis software of the tensile tester, or by integrating the measurement data of the tensile breaking strength and tensile breaking elongation. The tensile breaking strength can also be determined by carrying out a tensile test under the same conditions as for the tensile breaking elongation, and details will be described later.

[0047] Tensile Breaking Strength In one embodiment, the tensile breaking strength of the monofilament of regenerated cellulose fiber (B) may be 1.1 to 10.0 cN / dtex, 3.0 to 7.0 cN / dtex, or 4.8 to 5.5 cN / dtex. The tensile breaking strength of the monofilament of regenerated cellulose fiber (B) can be measured by the following method.

[0048] (Method for measuring tensile breaking strength of monofilament) The tensile modulus of the monofilament of regenerated cellulose fiber (B) is measured in accordance with JIS L1015. Specifically, a single fiber is taken from the monofilament or multifilament to be measured to form a monofilament, and then a tensile test is carried out using an automatic single-fiber fineness meter and a strength and elongation meter (e.g., manufactured by Lenzing Instruments / Austria, product names "Vibroskop Micro" and "Vibrodyn 500") at a temperature of 20°C and a relative humidity of 65% under conditions of a chuck distance of 20 mm and a pulling speed of 20 mm / min. In this tensile test, the load (tensile breaking strength) at which the monofilament breaks (breaks) is measured. The test is carried out 15 or more times, and the average value is calculated, and the value rounded to one decimal place is used as the tensile breaking strength.

[0049] Fineness: In one embodiment, the fineness of the monofilament of the regenerated cellulose fiber (B) is preferably 0.1 to 30 dtex, more preferably 1 to 20 dtex, even more preferably 1 to 10 dtex, and particularly preferably 1 to 3 dtex. When the monofilament fineness is within this range, the tensile elongation at break is likely to be 10% or more. Furthermore, the kneadability with the thermoplastic resin (A) is likely to be improved, making it easier to obtain molded products with excellent mechanical properties. The fineness refers to the weight (g) per 10,000 m of monofilament length and can be measured under the following conditions.

[0050] (Method for measuring monofilament fineness) A single fiber is taken out from the monofilament or multifilament to be measured to make a monofilament, and then the monofilament fineness is measured using an automatic single yarn fineness measuring device (for example, product name "Vibroskop Micro" manufactured by Lenzing Instruments / Austria) in an environment of a temperature of 20°C and a relative humidity of 65%.

[0051] Average fiber diameter In one embodiment, the average fiber diameter of the monofilament of the regenerated cellulose fiber (B) is preferably 10 to 16 μm, more preferably 10 to 14 μm. The average fiber diameter can be measured from an SEM image of the cross section of the monofilament, but it may also be calculated from the fineness of the monofilament. When calculating from the fineness, it is calculated by the following formula, assuming that the cross section of the monofilament is a perfect circle: [(fineness (dtex) ÷ density (g / cm ３ ) ÷ 10,000 ÷ 1,000,000 ÷ π) ０．５ × 1,000,000 × 2]. The density represents the density of the monofilament, and the average fiber diameter is a value calculated assuming the density is 1.5.

[0052] Long axis length / short axis length In one embodiment, the ratio of the long axis length to the short axis length (long axis length / short axis length) in the cross section of the monofilament of regenerated cellulose fiber (B) in the width direction is preferably 1.2 or less, more preferably 1.1 or less. In one embodiment, the long axis length / short axis length may be 1.09 or less. Fibers with a long axis length / short axis length of 1.2 or less have a substantially circular or substantially elliptical cross section in the width direction. The long axis length / short axis length of the regenerated cellulose fiber (B) can be measured by the following method.

[0053] (Method for measuring the long axis length / short axis length of a monofilament) Regenerated cellulose fiber (B) is embedded in epoxy resin, and a cross section is cut out with a microtome (or a razor) to take an SEM photograph. The length of the longest part of the cross section of the monofilament in the SEM photograph is taken as the "long axis length," and the length of the longest part of the line (axis) perpendicular to the long axis is taken as the "short axis length," and the ratio of the long axis length to the short axis length is calculated. The same measurement is performed on 100 monofilaments in the SEM photograph, and the average value is taken as the "long axis length / short axis length."

[0054] Average Fiber Length: In one embodiment, the average fiber length of the regenerated cellulose fibers (B) in the resin composition is preferably 3 to 100 mm, more preferably 3 to 50 mm, and even more preferably 4 to 10 mm. By including regenerated cellulose fibers (B) having such an average fiber length, the mechanical strength of the molded product is likely to be improved. The average fiber length of the fibers (B) in the resin composition can be calculated as the average fiber length of monofilaments measured by dissolving and removing the resin of the resin composition with an organic solvent (e.g., xylene), dispersing the fibers (B) in a medium, and performing image processing on the fibers (B). Furthermore, when the resin composition is a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B1) described below, the major axis lengths of approximately 100 pellets of the thermoplastic resin-impregnated regenerated cellulose fiber bundle (B1) can be measured with a vernier caliper or the like, and the average length can be calculated from the measured values.

[0055] Nitrogen Content: In one embodiment, the nitrogen content of the regenerated cellulose fiber (B) is preferably 1% by mass or less, and more preferably 0.5% by mass or less. The nitrogen content is likely to decrease during the production of the regenerated cellulose fiber (B) by extending the washing process of the filaments (e.g., washing for 3 hours or more), but from the viewpoint of productivity, a long washing process is not preferable. From the viewpoint of easily achieving both productivity and various physical properties such as tensile elongation at break, the nitrogen content of the fiber (B) may be 0.05 to 0.3% by mass, or may be 0.05 to 0.2% by mass. The nitrogen content of the fiber (B) can be measured by the following method.

[0056] (Method for Measuring Nitrogen Content) Measurement is performed using a combustion elemental analyzer (for example, Sumika Chemical Analysis Center, Ltd., product name "SUMIGRAPH (registered trademark) NC-220F"). A blank (empty sample) and a standard substance, DL-aspartic acid, are used to create a calibration curve. First, the weight of a sample of regenerated cellulose fiber (B) is measured. Then, the fiber (B) is pyrolyzed and oxidized, and the nitrogen and nitrogen oxide gases in the combustion gas are reduced to nitrogen in a reduction tube and detected and quantified using a thermal conductivity detector (TCD) gas chromatograph. The quantification is calculated as the total amount of nitrogen using the calibration curve. The temperatures (units: °C) of the furnace (FURNACE) used for pyrolysis and oxidation are set as follows: NC-L (reduction temperature): 600 °C, NC-H (reaction temperature): 870 °C. The various measurement times are set as follows: PURGE: 50 minutes, PUMP: 150 minutes, MEAS.: 100 minutes. The nitrogen content is calculated from the total nitrogen amount thus obtained and the weight of the fiber (B) weighed during the measurement.

[0057] Tensile Modulus In one embodiment, the tensile modulus (Young's modulus) of the monofilament of fiber (B) may be 14 GPa or more, 17 GPa or more, or 19 GPa or more. If the tensile modulus is too high, the tensile elongation at break tends to decrease. Therefore, from the viewpoint of easily achieving both the tensile modulus and the tensile elongation at break, the tensile modulus may be 25 GPa or less, 23 GPa or less, or 20 GPa or less. From the viewpoint of easily achieving good mechanical properties, the tensile modulus of fiber (B) may be 14 to 25 GPa, 15 to 23 GPa, 16 to 20 GPa, or 16 GPa or more but less than 20 GPa. The tensile modulus of fiber (B) can be measured by the following method.

[0058] (Method for measuring tensile modulus of monofilament) The tensile modulus of the monofilament of fiber (B) is measured in accordance with JIS L1015. Specifically, a single fiber is taken out from the monofilament or multifilament to be measured to form a monofilament, and then a tensile test is carried out under conditions of a temperature of 20°C and a relative humidity of 65% using an automatic single-fiber fineness measuring device and a strength and elongation measuring device (for example, manufactured by Lenzing Instruments / Austria, product names "Vibroskop Micro" and "Vibrodyn 500") at a chuck distance of 20 mm and a tensile speed of 20 mm / min. The test is carried out 15 or more times, and the average value is calculated, and the value obtained by rounding off the first decimal place is used.

[0059] In one embodiment, the relationship between the tensile breaking strength and the tensile modulus of the monofilament of fiber (B) preferably satisfies the following formula (1): 8≧M−5.29S (1) (In formula (1), M represents the tensile modulus of the monofilament (GPa), and S represents the tensile breaking strength of the monofilament (cN / dtex).) The tensile modulus and the tensile breaking strength in formula (1) are values ​​measured by the above-mentioned method. When fiber (B) satisfies formula (1), productivity is likely to be good, and the tensile breaking elongation of the monofilament is likely to be 10% or more. In one embodiment, (M−5.29S) in formula (1) is preferably 5 or less, more preferably 2 or less. Note that (M−5.29S) in formula (1) may be less than 0 (a negative value). In one embodiment, (M−5.29S) is preferably −0.5 or less, more preferably −0.61 or less. The lower limit of (M-5.29S) is not particularly limited as long as the effects of the present disclosure are achieved, but may be, for example, -100 or more, -50 or more, or -10 or more.

[0060] <Method for producing regenerated cellulose fiber (B)> The regenerated cellulose fiber (B) according to the first embodiment can be produced by a solvent method. Preferably, it is produced by a solvent method using an ionic liquid. The ionic liquid preferably contains imidazolium ions. A preferred embodiment of a method for producing regenerated cellulose fiber (B) using a solvent containing imidazolium ions will be described below.

[0061] The fiber (B) can be produced by a method including dissolving raw cellulose in a solvent containing imidazolium ions to prepare a cellulose solution (dope), extruding the dope from a nozzle and bringing it into contact with a coagulation liquid, coagulating the dope in the coagulation liquid to obtain filaments, washing and drying the obtained filaments, and winding the dried filaments onto a bobbin. In these steps, setting a low draft ratio during spinning makes it easier to prepare regenerated cellulose fiber (B).

[0062] (Preparation of Dope) The dope is prepared by dissolving raw cellulose in a solvent containing imidazolium ions. The raw cellulose may be an unprocessed cellulose material derived from natural plants such as wood, cotton, or hemp, or a processed plant-derived cellulose material such as pulp or paper. It may also be regenerated cellulose fibers such as rayon, lyocell, or solvent-processed cellulose. Clothing, fabrics, yarn, etc., made from these materials may be reused as raw cellulose. The raw cellulose may be in any form, such as fiber, powder, bulk, liquid, or slurry. The properties of the raw cellulose can be appropriately selected depending on the intended use of the resin composition. The average degree of polymerization of the raw cellulose is preferably 400 to 2500, more preferably 500 to 2000, and even more preferably 600 to 1300. If the average degree of polymerization is too low, the physical properties of the fiber (e.g., tensile strength at break, tensile modulus, toughness, tensile elongation at break, etc.) may be insufficient. If the average degree of polymerization is too high, spinnability may be poor. By using a raw material cellulose having an average degree of polymerization within the above range, it becomes easier to achieve both good physical properties and good spinnability of the fiber (B).

[0063] In one embodiment, the dope is preferably prepared by dissolving the starting cellulose in a solvent under reduced pressure with heating. The heating temperature is preferably in the range of 80 to 150° C. From the viewpoints of dispersibility and solubility, the concentration of the starting cellulose in the dope is preferably 3 to 20% by mass, more preferably 9 to 13% by mass.

[0064] The ionic liquid contained in the solvent that dissolves the starting cellulose refers to a compound having a cation moiety and an anion moiety that has a melting point of 100°C or less. Of these, the cation moiety preferably contains an imidazolium ion. Examples of imidazolium ions include ions represented by the following formula (I):

[0065] [In formula (I), R ６ ~R ７ are each independently an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and R ８ ~R １０each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0066] In formula (I), the alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic, and is preferably linear or branched, and more preferably linear. A preferred specific example of the imidazolium ion represented by formula (I) is shown in formula (II) below.

[0067] [In formula (II), R １ represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, and R ２ represents a hydrogen atom or a methyl group, and R ３ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.]

[0068] In addition, preferred specific examples of the imidazolium ion represented by formula (II) are shown as the following formulae (III) to (V): Of the imidazolium ions represented by formulae (III) to (V), those containing formula (IV) are particularly preferred.

[0069]

[0070]

[0071]

[0072] Examples of the anion moiety include halogen ions, carboxylate ions, phosphinate ions, phosphate ions, and phosphonate ions. Examples of halogen ions include chloride ions, bromide ions, and iodide ions, with chloride ions being preferred. Examples of carboxylate ions include formate ions, acetate ions, propionate ions, butyrate ions, hexanoate ions, maleate ions, fumarate ions, oxalate ions, lectate ions, and pyruvate ions, with formate ions, acetate ions, and propionate ions being preferred.

[0073] Preferred ionic liquids that can be used in the production method of this embodiment include, for example, 1-allyl-3-methylimidazolium chloride (AmimCl), 1-ethyl-3-methylimidazolium acetate (C ２ mimAc), 1-ethyl-3-methylimidazolium diethyl phosphate (C ２ mimDEP), 1-ethyl-3-methylimidazolium methylphosphonate (C ２ mimMEP), 1-ethyl-3-methylimidazolium phosphinate (C ２ mimHPO), 1-butyl-3-methylimidazolium acetate (C ４ mimAc), or 1-butyl-3-methylimidazolium chloride (C ４ More preferred are imidazolium chlorides, such as 1-butyl-3-methylimidazolium chloride (C ４ mimCl) is particularly preferred.

[0074] (Preparation of monofilament or multifilament) The dope prepared above is discharged from a nozzle and taken up while being brought into contact with a coagulation liquid to prepare a monofilament (or multifilament). As the coagulation liquid, water, a lower alcohol, a polar solvent, a non-polar solvent, etc. can be used. The coagulation liquid may also contain a solvent such as an ionic liquid. From the viewpoint of reducing the environmental load, it is preferable that the coagulation liquid contains water. The temperature of the coagulation liquid can be set within any range.

[0075] The diameter of the nozzle for discharging the dope is preferably 0.05 mm to 1.0 mm, more preferably 0.1 to 0.3 mm. The take-up speed is preferably 70 to 120 m / min, more preferably 80 to 110 m / min, from the viewpoint of the draft ratio described below.

[0076] In one embodiment, from the viewpoint of easily obtaining fiber (B) having a tensile elongation at break of 10% or more and a toughness of 35 MPa or more, the draft ratio (take-up speed / discharge linear speed), which is expressed as the take-up speed relative to the discharge linear speed of the dope from the nozzle, is preferably 20 or less, more preferably 10 or less, even more preferably less than 10, and particularly preferably 6 or less. As described above, the regenerated cellulose fiber (B) according to the first embodiment can be easily prepared by using a solvent containing imidazolium ions as the ionic liquid and by setting the draft ratio (take-up speed / discharge linear speed) to preferably less than 10. Furthermore, by using the above draft ratio and spinning the regenerated cellulose fiber (B) so that the final monofilament fineness is 3 dtex or less, fiber (B) having the above properties can be more easily obtained.

[0077] In the production method according to this embodiment, the solvent may be removed in a coagulation liquid, or the obtained monofilament or multifilament may be further washed to remove the solvent. When washing is included, washing with water is preferable. The time for removing the solvent is not particularly limited, but from the viewpoint of easily achieving both productivity and the physical properties of the fiber (B), it is preferable to adjust the time for removing the solvent so that the nitrogen content in the finally obtained regenerated cellulose fiber (B) is 1% by mass or less, more preferably 0.05 to 0.3% by mass, and even more preferably 0.05 to 0.2% by mass.

[0078] <Thermoplastic Resin-Impregnated Regenerated Cellulose Fiber Bundle (B1)> The resin composition according to the first embodiment preferably contains a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B1) (hereinafter referred to as "fiber bundle (B1)") in which regenerated cellulose fibers (B) aligned in the length direction are bundled and impregnated with the thermoplastic resin (A). The fiber bundle (B1) is a composite material obtained by impregnating a fiber bundle of regenerated cellulose fibers (B) aligned in the length direction with the thermoplastic resin (A) and then cutting the fiber bundle. In one embodiment, the resin composition may contain the fiber bundle (B1) and another thermoplastic resin, or may contain only the fiber bundle (B1).

[0079] The average fiber length of the regenerated cellulose fibers (B) in the fiber bundle (B1) can be the same as the average fiber length of the regenerated cellulose fibers (B) in the resin composition described above, i.e., the average fiber length is preferably 3 to 100 mm, more preferably 3 to 50 mm, and even more preferably 4 to 10 mm.

[0080] The number of monofilaments in the fiber bundle (B1) is preferably 2,000 to 30,000, more preferably 3,000 to 25,000, and even more preferably 5,000 to 25,000. By impregnating a multifilament obtained by bundling the above number of monofilaments with the thermoplastic resin (A), the thermoplastic resin (A) can be easily impregnated all the way to the center of the fiber bundle (B1). As a result, when a resin composition containing the fiber bundle (B1) is molded, a molded product with a better appearance and superior mechanical strength can be easily obtained. Furthermore, manufacturing problems such as breakage of the fiber bundle are less likely to occur during the production of the fiber bundle (B1).

[0081] (Method for producing fiber bundle (B1)) In one embodiment, the fiber bundle (B1) can be produced by a well-known production method using a die. Specifically, the production methods described in JP-A-6-313050, JP-A-2007-176227, JP-B-6-2344, etc. can be applied.

[0082] In one embodiment, when the fiber bundle (B1) is composed of a thermoplastic resin (A) and regenerated cellulose fibers (B), the proportion of the regenerated cellulose fibers (B) relative to the total mass of the fiber bundle (B1) is preferably 5 to 70% by mass, more preferably 20 to 70% by mass, and even more preferably 25 to 70% by mass. The proportion of the thermoplastic resin (A) in the fiber bundle (B1) is preferably 30 to 95% by mass, more preferably 30 to 80% by mass, and even more preferably 30 to 75% by mass. By adjusting the proportion of the regenerated cellulose fibers (B) relative to the total mass of the fiber bundle (B1) within the above range, molded articles with good mechanical properties are more likely to be obtained.

[0083] <Other Components> The resin composition according to the first embodiment may contain components (other components) other than the thermoplastic resin (A) and the fiber (B) as long as the effects of the present invention are not impaired. Examples of other components include, in addition to the other thermoplastic resins described above, softeners, surface lubricants, leveling agents, antioxidants, surfactants, corrosion inhibitors, light stabilizers, UV absorbers, heat stabilizers, polymerization inhibitors, silane coupling agents, lubricants, plasticizers, crystallization accelerators, hydrolysis inhibitors, inorganic fillers, colorants, release agents, antistatic agents, organic fillers other than solvent-process regenerated cellulose fibers, metal powders, pigments, epoxy compounds, and other additives. These additives may be used alone or in combination of two or more.

[0084] [Method for Producing Resin Composition] The method for producing the resin composition according to the first embodiment is not particularly limited, and the resin composition may be produced by a method including mixing the resin (A), the regenerated cellulose fibers (B), and, if necessary, optional components by a conventional method. For example, the components may be mixed and kneaded and extruded using a single-screw or twin-screw extruder to obtain pellets of the resin composition. In one embodiment, a resin composition comprising the fiber bundle (B1) (or a resin composition containing the fiber bundle (B1) and other components) may be obtained by a method including obtaining the fiber bundle (B1) by the above-described method for producing the fiber bundle (B1) (e.g., a method in which a molten impregnation resin containing the resin (A) and, if necessary, optional components is impregnated into a fiber bundle of regenerated cellulose fibers (B) that has been passed through a crosshead die and aligned in the length direction, thereby preparing the fiber bundle (B1)), and optionally mixing the fiber bundle (B1) with other components.

[0085] [Pellets] A second embodiment of the present disclosure relates to pellets. The pellets according to the second embodiment can be obtained by producing the resin composition according to the first embodiment, for example, by the method for producing the resin composition described above. The pellets according to the second embodiment contain the regenerated cellulose fiber (B) described above, and therefore have the characteristic of being less colored than pellets containing viscose rayon.

[0086] <Molded article and manufacturing method thereof> A third embodiment of the present disclosure relates to a molded article. The molded article according to the third embodiment includes the resin composition described above. Preferably, the molded article is obtained by molding the resin composition according to the first embodiment. The molded article according to the third embodiment may be obtained by injection molding the resin composition according to the first embodiment, or may be obtained by press molding. The molded article according to the third embodiment has a lower environmental impact and good mechanical properties.

[0087] [Applications] The molded article according to the third embodiment has a lower environmental impact and good mechanical properties. Such a molded article can be used in a variety of applications as an environmentally friendly resin molded article. Among these, it can be suitably used for, for example, automobile parts, electrical and electronic product parts, industrial products, daily necessities, etc.

[0088] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure are set forth below: [1] A thermoplastic resin (A) and a CS ２A resin composition comprising: a regenerated cellulose fiber (B) containing no cellulose ester; the regenerated cellulose fiber (B) having a tensile breaking elongation of 10% or more and a toughness of 35 MPa or more, as measured in accordance with JIS L 1015. [2] The resin composition according to [1], wherein the ratio of the major axis length to the minor axis length (major axis length / minor axis length) in the cross section in the width direction of the monofilament is 1.2 or less. [3] The resin composition according to [1] or [2], wherein the regenerated cellulose fiber (B) has a nitrogen content of 1% by mass or less. [4] The resin composition according to any one of [1] to [3], wherein the resin composition comprises a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B1) obtained by bundling the regenerated cellulose fibers (B) aligned in the length direction and impregnating the fiber bundle with the thermoplastic resin (A). [5] The resin composition according to any one of [1] to [4], wherein the proportion of the thermoplastic resin (A) is 30 to 95% by mass and the proportion of the regenerated cellulose fiber (B) is 5 to 70% by mass, relative to the total mass of the resin composition. [6] The resin composition according to any one of [1] to [5], wherein the regenerated cellulose fibers (B) in the resin composition have an average fiber length of 3 to 100 mm. [7] The resin composition according to any one of [1] to [6], wherein the thermoplastic resin (A) comprises one or more thermoplastic resins selected from the group consisting of crystalline resins (a1) having a melting point of 250°C or less and amorphous resins (a2) having a glass transition temperature of 150°C or less. [8] The resin composition according to [7], wherein the thermoplastic resin (A) comprises one or more crystalline resins (a1) selected from polyolefin-based resins, polyamide-based resins, and polyacetal-based resins. [9] Pellets of the resin composition according to any one of [1] to [8].

[0089] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description.

[0090] <Preparation of Regenerated Cellulose Fiber (B-1)> Raw cellulose (pulp, degree of polymerization 1180, manufactured by Georgia Pacific) was added to an aqueous solution containing 1-butyl-3-methylimidazolium chloride (ionic liquid) and mixed at 140°C to prepare a dope (raw cellulose concentration: 11%). The dope was discharged from a nozzle (nozzle diameter: 0.1 mm) at a take-up speed of 100 m / min, contacted with a coagulation liquid (water containing the ionic liquid), and then washed with water (approximately 1 hour). The draft ratio (take-up speed / extrusion linear velocity) at this time was 5.9. The resulting multifilament was then collected while drying with hot air to obtain regenerated cellulose fiber (B-1). The monofilament fineness of the resulting regenerated cellulose fiber (B-1) was 1.98 dtex. The tensile breaking elongation, tensile breaking strength, tensile modulus, average fiber diameter, major axis length / minor axis length, and nitrogen content of the regenerated cellulose fiber (B-1) were measured under the following conditions. The results are shown in Table 1.

[0091] <Preparation of Regenerated Cellulose Fiber (B-2)> Regenerated cellulose fiber (B-2) was produced in the same manner as regenerated cellulose fiber (B-1), except that the dope temperature was 150°C and the take-up speed was 200 m / min (draft ratio: 5.8). The monofilament fineness of the resulting regenerated cellulose fiber (B-2) was 2.01 dtex. The tensile breaking elongation, tensile breaking strength, tensile modulus, average fiber diameter, major axis length / minor axis length, and nitrogen content of regenerated cellulose fiber (B-2) were measured under the following conditions. The results are shown in Table 1.

[0092] (Measurement of tensile elongation at break, tensile strength at break, and tensile modulus) The tensile elongation at break, tensile strength at break, and tensile modulus of the monofilament of regenerated cellulose fiber (B) were measured in accordance with JIS L 1015. Specifically, a single fiber was taken out of the monofilament or the multifilament to be measured to make a monofilament, and then a tensile test was carried out under conditions of a temperature of 20°C and a relative humidity of 65% using an automatic single-fiber fineness measuring instrument and a strength and elongation measuring instrument (manufactured by Lenzing Instruments / Austria, product names "Vibroskop Micro" and "Vibrodyn 500") at a chuck distance of 20 mm and a tensile speed of 20 mm / min, to measure the tensile elongation at break, tensile strength at break, and tensile modulus. The number of tests was 15 or more, and the average value was calculated, and the value rounded to one decimal place was used.

[0093] (Method of measuring toughness) Using the stress-strain curve (so-called SS curve) obtained by the tensile test such as the tensile elongation at break, the toughness was calculated by determining the area enclosed by the curve from the origin to the breaking point. The area was determined by analysis using the analysis software of the tensile tester.

[0094] (Measurement of average fiber diameter) From the fineness of the monofilament, [(fineness (dtex) ÷ density (g / cm ３ ) ÷ 10,000 ÷ 1,000,000 ÷ π) ０．５ The average fiber diameter was calculated as follows: [×1,000,000×2]. The density was calculated as 1.5.

[0095] (Measurement of major axis length / minor axis length) Regenerated cellulose fiber (B) was embedded in epoxy resin, and a cross section was excised using a microtome (or a razor) to take an SEM photograph (SEM used: Hitachi High-Tech Corporation, product name "FlexSEM 1000 II"). The length of the longest part of the cross section of the monofilament in the SEM photograph was taken as the "major axis length," and the length of the longest part of the line (axis) perpendicular to the major axis was taken as the "minor axis length," and the ratio of the major axis length to the minor axis length was calculated. The same measurement was performed on 100 monofilaments in the SEM photograph, and the average value was taken as the "major axis length / minor axis length."

[0096] (Measurement of Nitrogen Content) Measurement was performed using a combustion method elemental analyzer (manufactured by Sumika Chemical Analysis Center, Ltd., product name "SUMIGRAPH (registered trademark) NC-220F"). A blank (empty sample) and a standard substance, DL-aspartic acid, were used to create a calibration curve. First, the weight of a sample of regenerated cellulose fiber (B) was measured. Then, the fiber (B) was pyrolyzed and oxidized, and the nitrogen and nitrogen oxide gases in the combustion gas were reduced to nitrogen in a reduction tube and detected and quantified using a thermal conductivity detector (TCD) gas chromatograph. The quantification was calculated as the total amount of nitrogen using the calibration curve. The temperatures (unit: °C) of the furnace (FURNACE) used for pyrolysis and oxidation were set at NC-L (reduction temperature): 600 °C and NC-H (reaction temperature): 870 °C. The various measurement times were set as follows: PURGE: 50 minutes, PUMP: 150 minutes, and MEAS.: 100 minutes. The nitrogen content was calculated from the total nitrogen amount thus obtained and the weight of the fiber (B-1) weighed during the measurement.

[0097] <Preparation of Regenerated Cellulose Fiber (B'-1)> Regenerated cellulose fiber (B'-1) was prepared in the same manner as regenerated cellulose fiber (B-1), except that starting cellulose with a degree of polymerization of 630 was used, the nozzle diameter was 0.3 mm, and the draft ratio was 47.9. The monofilament fineness of the resulting regenerated cellulose fiber (B'-1) was 1.92 dtex. The tensile breaking elongation, tensile breaking strength, tensile modulus, average fiber diameter, major axis length / minor axis length, and nitrogen detectability of regenerated cellulose fiber (B'-1) were measured under the same conditions as those for fiber (B-1). The results are shown in Table 1.

[0098] Other regenerated cellulose fibers (B') used were as follows: <Regenerated cellulose fibers (B')> Regenerated cellulose fibers (B'-2): BioMid Fiber (solvent-process regenerated cellulose fibers).

[0099]

[0100] The following were used as raw materials for the resin composition other than the regenerated cellulose fibers. <Thermoplastic resin (A)> Resin (a1-1): Propylene homopolymer (PP homopolymer, manufactured by SunAllomer Co., Ltd., product name "PMB02A", melting point: 164°C, melt flow rate (230°C, 2.16 kg load): 70 g / 10 min). Resin (a1-2): Maleic anhydride modified polypropylene resin (manufactured by SK Functional Polymer, product name "OREVAC CA100", melting point: 167°C). <Other components> Antioxidant (1): Hindered phenol-based antioxidant (manufactured by BASF Japan Ltd., product name "Irganox (registered trademark) 1010FF"). Antioxidant (2): Phosphorus-based antioxidant (manufactured by BASF Japan Ltd., product name "Irgafos (registered trademark) 168") Light stabilizer: Hindered amine-based light stabilizer (manufactured by BASF Japan Ltd., product name "Tinuvin (registered trademark) 111FDL").

[0101] <Preparation of Resin Composition> [Example 1] 67.5% by mass of resin (a1-1), 2.1% by mass of resin (a1-2), 0.2% by mass of antioxidant (1), 0.1% by mass of antioxidant (2), and 0.1% by mass of light stabilizer were mixed and charged into a twin-screw extruder, and then melt-kneaded at a cylinder temperature of 260 ° C. to obtain a molten resin. The regenerated cellulose fiber (B-1) was passed through a crosshead die and impregnated into a fiber bundle of 5,400 fibers aligned in the longitudinal direction so that the fiber (B-1) was 30% by mass. The fiber bundle was then shaped using a shaping nozzle at the crosshead die outlet, shaped using a shaping roll, and cut to a length of 7 mm using a pelletizer to obtain the resin composition of Example 1 consisting of a pelletized fiber bundle (B1). The mechanical properties of the resulting resin composition were evaluated under the following conditions. The results are shown in Table 2.

[0102] <Evaluation of Mechanical Properties> The resin composition (pellets) of each example was injection molded under the following conditions to obtain a molded article (ISO test piece). The obtained molded article was measured for various mechanical properties under the following conditions. The results are shown in Table 2. (Molding conditions) Molding machine: FANUC Corporation, product name "α-S150iA". Test piece: ISO test piece. Molding temperature: 200°C. Mold temperature: 60°C.

[0103] <Evaluation of Tensile Strength and Tensile Elongation> Using the obtained ISO test pieces (dumbbell-shaped type 1A test pieces, total length: 170 mm, parallel portion length: 80 mm, thickness: 4 mm), the tensile strength and tensile elongation were measured in accordance with ISO 527-1 and 2. Specifically, the tensile strength (MPa) and tensile elongation (%) were measured using a tensile tester (manufactured by Shimadzu Corporation, product name "Autograph (registered trademark) AG-X plus") under conditions of 23°C, humidity of 50%, a tensile speed of 5 mm / min, and a chuck distance of 115 mm.

[0104] <Methods for Measuring Flexural Strength, Flexural Modulus, and Charpy Impact Strength> Using the obtained ISO test pieces (dumbbell-shaped Type 1A test pieces cut into 80 mm x 10 mm x 4 mm), flexural strength and flexural modulus were measured in accordance with ISO 178. Furthermore, using test pieces cut into the same shape, notched Charpy impact strength was measured in accordance with ISO 179 / 1eA. Specifically, flexural strength and flexural modulus were measured using a bending test measuring device (Shimadzu Corporation, product name "Shimadzu Autograph AG-X / R") under conditions of 23°C, 50% humidity, and a support distance of 64 mm. Notched Charpy impact strength was measured using a digital impact tester (Yasuda Seiki Seisakusho Co., Ltd., model: 258D) under conditions of 23°C, 50% humidity, and a hammer force of 4J.

[0105] <Method for measuring deflection temperature under load (HDT)> The deflection temperature under load of the obtained ISO test pieces was measured in accordance with ISO 75-1 and 2. The bending stress was set to 1.8 MPa.

[0106] [Example 2, Comparative Examples 1 and 2] Resin compositions (pellets) of Example 2 and Comparative Examples 1 and 2 were obtained in the same manner as Example 1, except that the fibers shown in Table 2 were used as the regenerated cellulose fibers (B). The mechanical properties of the resin compositions of each example were evaluated under the same conditions as in Example 1. The results are shown in Table 2.

[0107]

[0108] As shown in Table 2, the fiber (B) (CS ２ The resin compositions of Examples 1 and 2 containing regenerated cellulose fibers (regenerated cellulose fibers not containing cellulose ether, wherein the monofilament has a tensile breaking elongation of 10% or more and a toughness of 35 MPa or more) were superior in mechanical properties to the resin compositions of Comparative Examples 1 and 2 containing conventional solvent-process regenerated cellulose fibers. In particular, it was found that the Charpy impact strength was significantly improved.

[0109] Comparative Example 3 A resin composition (pellets) of Comparative Example 3 was obtained in the same manner as in Example 1, except that viscose rayon (manufactured by Kodenka Corporation, product name "CR500TEX") was used as the regenerated cellulose fiber. The resin composition of Comparative Example 3 was molded under the molding conditions for the mechanical property evaluation described above to obtain a molded article. Visual comparison of the discoloration levels of the molded article of Comparative Example 3 and the molded article of Example 1 (see FIG. 1 ) revealed that the discoloration level of the molded article of Example 1 was lower than that of the molded article of Comparative Example 3.

[0110] From the above results, it was found that the resin composition according to the first embodiment can produce molded articles with a lower environmental impact and good mechanical properties. It was also found that the resin composition according to the first embodiment can produce molded articles with less coloration than resin compositions containing viscose rayon. It should be noted that, among resin compositions containing solvent-process regenerated cellulose fibers, no resin composition capable of achieving the above-mentioned excellent mechanical properties (particularly Charpy impact strength) has been known to date, and the resin composition according to the present disclosure is a novel resin composition.

[0111] The resin composition according to the first embodiment has a lower environmental impact and good mechanical properties, and therefore, a molded article containing the resin composition can be suitably used as an environmentally friendly resin molded article for applications such as automobile parts, electrical and electronic product parts, industrial products, and daily necessities.

Claims

1. Thermoplastic resin (A) and CS ２ and (B) a regenerated cellulose fiber not containing cellulose ester, wherein the monofilament has a tensile breaking elongation of 10% or more and a toughness of 35 MPa or more as measured in accordance with JIS L 1015.

2. A resin composition according to claim 1, wherein the ratio of the major axis length to the minor axis length (major axis length / minor axis length) in the cross section of the monofilament of the regenerated cellulose fiber (B) in the width direction is 1.2 or less.

3. A resin composition according to claim 1 or 2, wherein the nitrogen content of the regenerated cellulose fibers (B) is 1% by mass or less.

4. A resin composition according to claim 1 or 2, comprising a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B1) in which the regenerated cellulose fibers (B) are bundled together and aligned in the length direction, and the thermoplastic resin (A) is impregnated into the bundle.

5. A resin composition according to claim 1 or 2, wherein the proportion of the thermoplastic resin (A) relative to the total mass of the resin composition is 30 to 95 mass%, and the proportion of the regenerated cellulose fiber (B) is 5 to 70 mass%.

6. A resin composition according to claim 1 or 2, wherein the regenerated cellulose fibers (B) in the resin composition have an average fiber length of 3 to 100 mm.

7. The resin composition according to claim 1 or 2, wherein the thermoplastic resin (A) comprises one or more thermoplastic resins selected from the group consisting of crystalline resins (a1) having a melting point of 250°C or less and amorphous resins (a2) having a glass transition temperature of 150°C or less.

8. The resin composition according to claim 7, wherein the thermoplastic resin (A) comprises one or more crystalline resins (a1) selected from polyolefin-based resins, polyamide-based resins, and polyacetal-based resins.

9. Pellets of the resin composition according to claim 1 or 2.

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