Rayon long fiber reinforced resin composition

Abstract

To provide rayon long fiber reinforced resin compositions with a good dispersion property of rayon fibers.SOLUTION: A rayon filament reinforced resin composition contains a resin impregnated rayon filament bundle in which thermoplastic resin (B) is impregnated and integrated into continuous fibers in which rayon fibers (A) are bundled in a length direction. A rayon fiber content is 5 to 70 mass percent and an impregnation ratio of the thermoplastic resin is 90 percent or more. <Impregnation Rate Test> As sample compositions, 450-550 resin-impregnated rayon filament bundles cut into pieces each having a length of 3-10 mm are immersed in water with aqueous pigment for 2 minutes at room temperature (20-30°C). After wiping off the aqueous pigment on the taken-out samples, appearance of the sample is visually observed. Samples that are continuously stained with the aqueous pigment from one end face to the other are designated as "resin-unimpregnated rayon filament bundles," and the impregnation rate of thermoplastic resin is determined by the following formula: Impregnation rate (%)=(total number of samples-number of resin-unimpregnated rayon filament bundles) / total number of samples×100.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a rayon long fiber reinforced resin composition with improved dispersibility of rayon fibers in a thermoplastic resin molded body, and a molded body obtained therefrom.

Background Art

[0002] Resin molded bodies are used as metal substitutes for weight reduction purposes. To enhance their mechanical strength, it is known to mold resin compositions blended with rayon fibers.

[0003] Patent Document 1 discloses an invention of a fiber reinforced resin composition containing (A) a polyamide resin selected from polyamide 6, polyamide 69, polyamide 610, polyamide 612, polyamide 11, polyamide 12, and polyamide 1010, and (B) a resin-coated long fiber bundle containing rayon fibers satisfying (b1) a fiber diameter of 5 to 30 μm and (b2) a tensile elongation of 10% or more, and describes that a lightweight molded body with good mechanical properties can be obtained.

[0004] Patent Document 2 discloses an invention of a fiber reinforced resin composition containing (A) a thermoplastic resin (excluding polyamide-based resins) and (B) a resin-coated long fiber bundle containing rayon fibers, wherein the rayon fibers of component (B) satisfy (b1) a fiber diameter of 5 to 30 μm, (b2) a tensile elongation of 10 to 20%, and (b3) a ratio of the long axis length to the short axis length (long axis length / short axis length) in the cross-sectional width direction of 1.2 to 1.8, and describes that a lightweight molded body with good mechanical properties can be obtained.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] The object of this disclosure is to provide a rayon long fiber reinforced resin composition in which the dispersibility of rayon fibers in a thermoplastic resin molded article is improved, and a molded article obtained therefrom. [Means for solving the problem]

[0007] This disclosure provides a rayon long fiber reinforced resin composition comprising a resin-impregnated rayon long fiber bundle in which rayon fibers (A) are bundled together in a longitudinal direction and then impregnated with a thermoplastic resin (B) to form an integrated continuous fiber, The present invention provides a rayon long fiber reinforced resin composition in which the rayon fiber content in the resin-impregnated rayon long fiber bundle is 5 to 70% by mass, and furthermore, the impregnation rate of the thermoplastic resin in the resin-impregnated rayon long fiber bundle, determined by the method described below, is 90% or more. <Impregnation Rate Test> 450 to 550 long strands of resin-impregnated rayon fibers, each cut to a length of 3 to 10 mm and having a circular or nearly circular cross-section, are used as samples. Immerse the sample in water containing an aqueous pigment at room temperature (20-30°C) for 2 minutes. After wiping off any water-based pigment adhering to the extracted sample, the sample's appearance is visually inspected. If visual inspection of the appearance is difficult, the sample can be divided into multiple sections along its length for further visual inspection, if necessary. A sample in which the aqueous pigment has continuously permeated from one end face to the other end face on the opposite side in the length direction is defined as a "resin-unimpregnated rayon long fiber bundle," and the impregnation rate of the thermoplastic resin is determined by the following formula. Impregnation rate (%) = (Total number of samples - Number of unimpregnated rayon long fiber bundles) / Total number of samples × 100

[0008] Furthermore, this disclosure relates to a rayon long fiber reinforced resin composition comprising a resin-impregnated rayon long fiber bundle in which a thermoplastic resin (B) is impregnated and integrated with a continuous fiber in which rayon fibers (A) are bundled together with the rayon fibers aligned in the longitudinal direction, The present invention provides a rayon long fiber reinforced resin composition in which the rayon fiber content in the resin-impregnated rayon long fiber bundle is 5 to 70% by mass, and furthermore, the impregnation rate of the thermoplastic resin in the resin-impregnated rayon long fiber bundle, determined by the method described below, is 90% or more. <Impregnation Rate Test> 450 to 550 long strands of resin-impregnated rayon fibers, cut into tape-like or sheet-like strips measuring 3 to 10 mm in width and 5 to 10 mm in length, are used as samples. Immerse the sample in water containing an aqueous pigment at room temperature (20-30°C) for 2 minutes. After wiping off any water-based pigment adhering to the sample, the sample's appearance is visually inspected. A sample in which the aqueous pigment has continuously permeated from one end face to the other end face on the opposite side in the length direction is defined as a "resin-unimpregnated rayon long fiber bundle," and the impregnation rate of the thermoplastic resin is determined by the following formula. Impregnation rate (%) = (Total number of samples - Number of unimpregnated rayon long fiber bundles) / Total number of samples × 100 [Effects of the Invention]

[0009] In the rayon long fiber reinforced resin composition of this disclosure, the resin-impregnated rayon long fiber bundles are easily defibrated during the manufacture of the molded article, and the rayon fibers are easily dispersed in the molded article. [Modes for carrying out the invention]

[0010] The rayon long fiber reinforced resin composition includes a resin-impregnated rayon long fiber bundle in which a thermoplastic resin (B) is impregnated into a continuous fiber in which rayon fibers (A) are bundled together with the rayon fibers aligned in the length direction.

[0011] (Resin-impregnated rayon long fiber bundles) The resin-impregnated rayon long fiber bundles include those with a circular or similar cross-sectional shape in the width direction in the first embodiment, and those with a tape-like or sheet-like planar shape in the second embodiment. Shapes whose cross-sectional shape in the width direction approximates a circle include ellipses and those with a ratio of the longest diameter to the shortest diameter (shortest diameter / longest diameter) of 0.6 to less than 1.0 (excluding the aforementioned ellipse). Tape-like or sheet-like materials are known as prepregs. The resin-impregnated rayon long fiber bundles may be in their original long length from the time of manufacture, or they may be cut to the required length.

[0012] The rayon fibers of component (A) can be those of known origin, for example, the rayon fibers described in Japanese Patent Publication No. 6453575 or the rayon fibers described in Japanese Patent Publication No. 6711876 can be used.

[0013] (A) Rayon fibers can be those produced by the viscose method, the copper ammonia method, or the solvent method. Specifically, fibers such as viscose rayon (viscose method), cupro (copper ammonia method), polynosic (viscose method), modal (solvent (NMMO) method), Tencel (solvent (NMMO) method), and BioMid (solvent (NMMO method)) can be used. In addition, fortisan, which is cellulose regenerated from cellulose acetate, Bocel, which is produced by liquid crystal spinning, and solvent-process rayons using solvents other than NMMO (N-methylmorpholine-N-oxide) can also be used. The rayon fibers of component (A) are preferably 150-600 TEX, more preferably 200-500 TEX, even more preferably 200-450 TEX, even more preferably 200-350 TEX, and even more preferably 200-300 TEX. 1 TEX is the mass of 1 g of fibers (bundles) per 1000 m.

[0014] (B) The thermoplastic resin may include polyolefin resins, polyamide resins, styrene resins, polycarbonate resins, polyvinyl chloride, polyvinylidene chloride, polycarbonate-based resins, acrylic resins, methacrylic resins, polyester resins, polyacetal resins, polyphenylene sulfide resins. In addition, biodegradable resins and biomass plastics (non-biodegradable) produced from organic resources such as biomass (resource crops such as sugarcane and corn, and waste such as household waste) can be mentioned. (B) The thermoplastic resin is preferably selected from polyolefin resins, polyamide resins, biodegradable resins, and biomass plastics, and more preferably has a melting point of 230 °C or lower.

[0015] Examples of polyolefin resins include polypropylene, high-density, low-density, and linear low-density polyethylene, poly-1-butene, polyisobutylene, copolymers of ethylene and propylene, ethylene-propylene-diene terpolymers (where the diene component as a raw material is 10% by mass or less), polymethylpentene, random, block, and graft copolymers of ethylene or propylene (50 mol% or more) and other copolymer monomers (such as vinyl acetate, alkyl methacrylate, alkyl acrylate, aromatic vinyl). Among these, polypropylene is preferred.

[0016] When using a polyolefin resin as the (B) component, it is preferable to use an acid-modified polyolefin in combination to facilitate impregnation into the rayon fiber bundle of the (A) component. Preferred acid-modified polyolefins include maleic acid-modified polyolefins (maleic acid-modified polypropylene) and maleic anhydride-modified polyolefins (maleic anhydride-modified polyolefins). When using an acid-modified polyolefin in combination as the (B) component, the acid amount in the (B) component (the amount of acid contained in the acid-modified polyolefin in the (B) component) is preferably formulated so as to be in the range of 0.005 to 0.5% by mass on average in terms of maleic anhydride.

[0017] As the polyamide resin, it is preferable to select one from aliphatic polyamides and aromatic polyamides. Examples of aliphatic polyamides include polyamide 6, polyamide 66, polyamide 69, polyamide 610, polyamide 1010, polyamide 612, polyamide 46, polyamide 11, and polyamide 12. Aromatic polyamides include those obtained from aromatic dicarboxylic acids and aliphatic diamines, or aliphatic dicarboxylic acids and aromatic diamines, such as nylon MXD10 (metaxylylenediamine and sebacic acid), nylon MXD6 (metaxylylenediamine and adipic acid), nylon 6T (hexamethylenediamine and terephthalic acid), nylon 6I (hexamethylenediamine and isophthalic acid), nylon 9T (nonanediamine and terephthalic acid), nylon 5MT (methylpentadiamine and terephthalic acid), and nylon 10T (decamethylenediamine and terephthalic acid). Among these, polyamide 6, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 1010, and polyamide MXD10 are preferred.

[0018] Examples of biodegradable resins include polylactic acid (PLA), PHA (polyhydroxyalkanoate) resins (such as PHBH [3-hydroxybutyrate-3-hydroxyhexanoic acid copolymer polyester]), bioPBS (polybutylene succinate), PBAT (polybutylene adipate terephthalate)-PLA compound, starch polyester resin, cellulose acetate (diacetate), PVA (polyvinyl alcohol), PGA (polyglycolic acid), PBS, PBSA (polybutylene succinate-co-adipate), PBAT, and PETS (polyethylene terephthalate succinate).

[0019] Examples of biomass plastics (non-biodegradable) include bio-PE, bio-PA11, bio-PA1010, bio-PET, bio-PTT (polytrimethylene terephthalate), bio-PA610, bio-PA410, bio-PA510, bio-PA56, bio-PA1012, bio-PA10T, bio-PA11T, bio-PAMXD10, bio-PC, bio-PU, aromatic polyester, bio-unsaturated polyester, biophenol resin, bio-epoxy resin, and cellulose acetate (triacetate).

[0020] The resin-impregnated rayon long fiber bundle of the first embodiment can be obtained by bundling approximately 1,000 to 30,000 rayon fibers of component (A) aligned in the length direction, and then impregnating them with a molten thermoplastic resin of component (B) to integrate them. Normally, since the product is manufactured using long rayon fibers as component (A), the resulting resin-impregnated rayon long fiber bundles include long bundles of any length (i.e., long bundles of a length derived from the length of the raw rayon fibers) and bundles cut to the required length. Resin-impregnated rayon long fiber bundles can be manufactured by a well-known manufacturing method using a die. In the manufacturing method using the die described above, a bundle of rayon long fibers is passed through the heated die and brought into contact with the molten component (B). By adjusting the die temperature range (the temperature at which the rayon fibers are heated) to preferably 190°C to 300°C, more preferably 200°C to 260°C, the impregnation of component (B) into the rayon fiber bundle of component (A) can be enhanced. Furthermore, this enhanced impregnation is preferable because it also enhances the dispersibility of the rayon fibers in the molded product obtained from the resin-impregnated rayon fiber bundle. The following are some well-known manufacturing methods using dies. For example, the manufacturing methods described in paragraph 7 of Patent Document 2 (JP-A-6-313050), paragraph 23 of Patent Document 3 (JP-A-2007-176227), as well as in JP-A-6-2344 (Method for manufacturing resin-coated long fiber bundles and molding method), JP-A-6-114832 (Fiber-reinforced thermoplastic resin structure and method for manufacturing the same), JP-A-6-293023 (Method for manufacturing long fiber-reinforced thermoplastic resin composition), JP-A-7-205317 (Method for extracting fiber bundles and method for manufacturing long fiber-reinforced resin structures), JP-A-7-216104 (Method for manufacturing long fiber-reinforced resin structures), JP-A-7-251437 (Method for manufacturing long fiber-reinforced thermoplastic composite materials and manufacturing apparatus), and JP-A-8-118490 (Crosshead die and method for manufacturing long fiber-reinforced resin structures) can be applied.

[0021] The resin-impregnated rayon long fiber bundle of the second embodiment can be obtained by arranging approximately 1,000 to 200,000 rayon fibers of component (A) aligned in the length direction, impregnating them with a thermoplastic resin of component (B) while it is heated and melted, and then compressing the bundle. In the method for producing resin-impregnated rayon long fiber bundles of the second embodiment, for the same reasons as in the resin-impregnated rayon long fiber bundles of the first embodiment, the heating temperature range of the rayon long fibers can be adjusted to preferably 190°C to 300°C, more preferably 200°C to 260°C. For example, the manufacturing methods described in Japanese Patent Publication No. 5705650 (Inorganic Fiber Wrapped Tape and Method for Manufacturing the Same), Japanese Patent Publication No. 5705651 (Carbon Fiber Wrapped Tape and Method for Manufacturing the Same), Japanese Patent Publication No. 5705652 (Organic Fiber Wrapped Tape and Method for Manufacturing the Same), Japanese Patent Publication No. 5592775 (Carbon Fiber Wrapped Tape and Method for Manufacturing the Same) can be applied.

[0022] The length of the resin-impregnated rayon long fiber bundle when cut and used according to the first embodiment (i.e., the length of the rayon fibers of component (A) contained in the resin-impregnated rayon long fiber bundle) is preferably 3 to 50 mm, more preferably 5 mm to 50 mm, and even more preferably 5 mm to 25 mm. A length of 3 mm or more can increase the mechanical strength of the molded article obtained from the composition, and a length of 50 mm or less improves moldability. The resin-impregnated rayon long fiber bundle of the second embodiment can be used by cutting it to the appropriate length for the application while it remains in its long fiber bundle form. When the resin-impregnated rayon long fiber bundle of the second embodiment is cut and used, its length is preferably 3 to 100 mm, more preferably 5 mm to 50 mm, and even more preferably 10 mm to 25 mm. A length of 3 mm or more can increase the mechanical strength of the molded article obtained from the composition, while a length of 100 mm or less improves moldability. The preferred width of the resin-impregnated rayon long fiber bundle of the second embodiment is 3 to 100 mm, more preferably 10 to 80 mm, and even more preferably 10 to 50 mm. This width can be adjusted by directly manufacturing the bundle to the specified width, or by cutting it after manufacturing. The preferred thickness of the resin-impregnated rayon long fiber bundle in the second embodiment is 0.1 to 0.5 mm.

[0023] The content of rayon fibers in component (A) of the resin-impregnated rayon long fiber bundles in the first and second embodiments is 5 to 70% by mass, preferably 5 to 50% by mass, and more preferably 5 to 40% by mass.

[0024] The resin-impregnated rayon long fiber bundles of the first and second embodiments have a thermoplastic resin impregnation rate of 90% or more, determined by the method described below. <Impregnation rate test of the first embodiment> 450 to 550 long strands of resin-impregnated rayon fibers, each cut to a length of 3 to 10 mm and having a circular or nearly circular cross-section, are used as samples. You can use resin-impregnated rayon long fiber bundles with an outer diameter (diameter if the cross-section is circular, or maximum diameter if the shape is elliptical or approximates a circle) in the range of 1.0 to 3.0 mm. Immerse the sample in water (water-based pigment concentration approximately 5% by mass) to which a water-based pigment (red) (product name SA-1 Aka, manufactured by Shachihata Co., Ltd.) has been added, at room temperature (20-30°C) for 2 minutes. After wiping off any water-based pigment adhering to the extracted sample, the sample's appearance is visually inspected. If visual inspection of the appearance is difficult, the sample can be divided into multiple sections along its length for further visual inspection, if necessary. When the thermoplastic resin used has high transparency, it is easy to visually inspect its appearance. However, when the thermoplastic resin used has low transparency, or when the outer diameter of the resin-impregnated rayon long fiber bundle is large, the appearance of the bundle can be visually inspected by dividing it into multiple sections along its length as needed. Alternatively, instead of water-based pigments, fluorescent paint can be used, and the impregnation state can be visually confirmed by shining a black light on it to check for color development. A sample in which the aqueous pigment has continuously permeated from one end face to the other end face on the opposite side in the length direction is defined as a "resin-unimpregnated rayon long fiber bundle," and the impregnation rate of the thermoplastic resin is determined by the following formula. Impregnation rate (%) = (Total number of samples - Number of unimpregnated rayon long fiber bundles) / Total number of samples × 100

[0025] <Impregnation rate test of the second embodiment> 450 to 550 long strands of resin-impregnated rayon fibers, cut into tape-like or sheet-like strips measuring 3 to 10 mm in width and 5 to 10 mm in length, are used as samples. Immerse the sample in water containing an aqueous pigment at room temperature (20-30°C) for 2 minutes. After wiping off any aqueous pigment adhering to the sample, the appearance of the sample is visually observed. Since the resin-impregnated rayon long fiber bundle of the second embodiment is in the form of a tape or sheet, its appearance can be easily observed visually. A sample in which the aqueous pigment has continuously permeated from one end to the other end on the opposite side in the length direction is defined as a "resin-unimpregnated rayon long fiber bundle," and the impregnation rate of the thermoplastic resin is determined by the following formula. Impregnation rate (%) = (Total number of samples - Number of unimpregnated rayon long fiber bundles) / Total number of samples × 100

[0026] In the manufacturing of resin-impregnated rayon long fiber bundles according to the first and second embodiments, if the thermoplastic resin impregnation of the rayon long fiber bundle is insufficient, a continuous gap may occur between the rayon long fiber and the thermoplastic resin from one end face to the other end face of the rayon long fiber bundle. When no gaps occur at all, the thermoplastic resin impregnation rate is 100%, and the more gaps there are, the lower the thermoplastic resin impregnation rate becomes. When the above impregnation rate test is performed, a red line can be observed indicating that the aqueous pigment has permeated from one end face of the resin-impregnated rayon long fiber bundle to the other end face on the opposite side in the length direction. This confirms that the portion of the red line is not impregnated with thermoplastic resin.

[0027] The rayon long fiber reinforced resin composition may contain, as necessary, a resin-impregnated rayon long fiber bundle of the first or second embodiment, and the thermoplastic resin of component (B) contained in the resin-impregnated rayon long fiber bundle, as well as an additional thermoplastic resin of component (B). In this case, the thermoplastic resin of component (B) contained in the resin-impregnated rayon long fiber bundle and the additional thermoplastic resin of component (B) may be the same or different. The rayon long fiber reinforced resin composition may contain, to the extent that it can solve the problems of this disclosure, other known flame retardants, flame retardant aids, heat stabilizers, lubricants, light stabilizers, antioxidants, colorants, mold release agents, and antistatic agents in addition to the resin-impregnated rayon long fiber bundles. These components may be contained in the resin-impregnated rayon long fiber bundles or may be contained separately from the resin-impregnated rayon long fiber bundles.

[0028] (A molded article made from a rayon long fiber reinforced resin composition) A molded article made of a rayon long fiber reinforced resin composition is obtained by molding a rayon long fiber reinforced resin composition containing a resin-impregnated rayon long fiber bundle according to the first or second embodiment described above. The resin-impregnated rayon long fiber bundles of the first or second embodiment contained in the rayon long fiber reinforced resin composition have good dispersibility in thermoplastic resins, so that the rayon fibers of component (A) can be uniformly dispersed in the resulting molded article. In particular, using rayon fibers with a strength of 150-400TEX improves dispersibility, but even with fibers ranging from over 400TEX to 600TEX, dispersibility in molded products can be improved in the same way as with 150-400TEX fibers by adjusting the temperature range during manufacturing and the number of filaments constituting the resin-impregnated rayon long fiber bundle (for example, 1,000-10,000 fibers, preferably 1,000-5,000 fibers).

[0029] The weight-average fiber length of the rayon fibers contained in a molded article made of a rayon long-fiber reinforced resin composition is preferably 3 mm or more, more preferably 3.5 mm or more, and even more preferably 4 mm or more. The longer the weight-average fiber length of the rayon fibers in the molded article, the higher the impact strength of the molded article can be, which is therefore preferable.

[0030] Furthermore, since molded articles obtained from rayon long fiber reinforced resin compositions are lighter than those containing inorganic fibers such as glass fibers (i.e., their density can be reduced), it is possible to obtain molded articles with a high specific modulus (flexural modulus / specific gravity). For example, when comparing a polypropylene molded article containing rayon filaments with a polypropylene molded article containing glass filaments, the specific modulus of elasticity increases as the amount of rayon fibers or glass fibers added increases, but the degree of increase is greater in the polypropylene molded article containing rayon filaments.

[0031] The molded body can be shaped to any desired form depending on the application. As mentioned above, the specific modulus of elasticity can be increased, so when it is made into a thin plate-shaped molded body, it is possible to obtain one that is lightweight and has high mechanical strength. When forming a molded body into a thin, plate-like shape, even with a thickness of, for example, 1 to 5 mm, it is possible to obtain a product with high mechanical strength. Furthermore, because it contains rayon fibers, it does not leave behind combustion residue like glass fibers when burned.

[0032] Molded articles obtained from rayon long fiber reinforced resin compositions are lightweight and have high mechanical strength (especially specific modulus), making them suitable for use in various fields such as electrical and electronic equipment, communication equipment, automobiles, building materials, sporting goods, and daily necessities. They are particularly suitable as acoustic components such as speaker cones, home appliance components such as vacuum cleaners and air conditioners, housings for various devices, and plate-shaped exterior materials.

[0033] The configurations and combinations thereof in each embodiment are examples only, and additions, omissions, substitutions, and other modifications are permitted as appropriate without departing from the spirit of this disclosure. This disclosure is not limited by the embodiments, but is limited only by the claims. [Examples]

[0034] <Ingredients used> (A) component Viscose rayon fiber bundle 1:TEX (fineness) 247, 1350 filaments. Viscose rayon fiber bundle 2: TEX (fineness) 512, 2700 filaments. (B) Component PP (Polypropylene): PMC20M (Manufactured by Sun Allomer Co., Ltd.) Acid-modified PP: Modic P908 (manufactured by Mitsubishi Chemical Corporation)

[0035] Manufacturing Example 1 Three bundles of rayon fiber 1 (component A) were passed together through a crosshead die at 200°C. At the same time, molten component (B) was supplied to the crosshead die from a twin-screw extruder in a ratio of rayon fiber bundle 1:polypropylene resin = 30% by mass:70% by mass, thereby impregnating the rayon fiber bundle 1 with polypropylene resin. Subsequently, the material was shaped using a shaping nozzle at the crosshead die outlet, then refined with a molding roll, and finally cut into 7mm lengths using a pelletizer to obtain pellet-shaped (cylindrical) resin-impregnated rayon long fiber bundles (rayon long fiber reinforced resin composition) (total number of filaments in the pellet: 4050). When the resin-impregnated rayon long fiber bundle obtained in this way was cut along its length and examined, it was found that the rayon fibers were almost parallel to the length. The impregnation rate was 95%.

[0036] Manufacturing Example 2 (A) Two bundles of rayon fiber 2 were passed together through a crosshead die at 290°C, except that resin-impregnated rayon long fiber bundles (rayon long fiber reinforced resin composition) were obtained in the same manner as in Production Example 1 (total number of filaments in the pellet: 5400). The impregnation rate was 85%.

[0037] Manufacturing Example 3 A resin-impregnated rayon long fiber bundle (rayon long fiber reinforced resin composition) was obtained using the same method as in Production Example 1, except that the ratio of rayon fiber bundle 1: polypropylene resin was 40% by mass:60% by mass (4,050 filaments in the pellet). The impregnation rate was 94%.

[0038] Manufacturing Example 4 A resin-impregnated rayon long fiber bundle (rayon long fiber reinforced resin composition) was obtained in the same manner as in Production Example 1, except that one strand of rayon fiber bundle 2 of component (A) was passed through a crosshead die at 260°C (2700 filaments in the pellet). The impregnation rate was 93%.

[0039] Example 1 The resin-impregnated rayon long fiber bundles (rayon long fiber reinforced resin composition) produced in Production Example 1 were injection molded to obtain 10 plate test pieces measuring 50 × 90 × 3 mm. Injection molding was carried out as follows: (Injection molding conditions) Molding machine: ROBOSHOT α-S100iA manufactured by FANUC Corporation Cylinder temperature: 200℃ Mold temperature: 60℃ Screw diameter: 36mm Gate shape: 6mm wide side gate

[0040] Examples 2 and 3 The resin-impregnated rayon long fiber bundles produced in Production Example 1 and the polypropylene resin of component (B) were dry-blended to the fiber content shown in Table 1, and 10 plate test pieces were obtained by injection molding in the same manner as in Example 1.

[0041] Comparative Example 1 Ten plate test pieces were obtained by injection molding the resin-impregnated rayon long fiber bundles produced in Manufacturing Example 2 in the same manner as in Example 1.

[0042] Comparative Examples 2 and 3 The resin-impregnated rayon long fiber bundles produced in Production Example 2 and the polypropylene resin of component (B) were dry-blended to achieve the fiber content shown in Table 1, and 10 plate test pieces were obtained by injection molding in the same manner as in Example 1.

[0043] <Testing Method> From the 10 plate specimens in each case, four plate specimens were randomly selected. The four selected plate specimens were visually observed, and the total number of fiber bundles that could be visually confirmed was counted.

[0044] [Table 1]

[0045] As is clear from the comparison between Examples 1-3 and Comparative Examples 1-3, Comparative Examples 1-3 had a large amount of fiber bundles remaining in the molded body. In Example 1, this amounted to 1.1 bundles / 100cm² when calculated by area. 2 This means that fiber bundles were confirmed, and in Comparative Example 1, there were 6.9 bundles / 100cm.2 This is attributed to differences in the impregnation rate of thermoplastic resin within the resin-impregnated rayon long fiber bundles. The difference in dispersibility between Examples 1-3 and Comparative Examples 1-3 is thought to be influenced by the difference in TEX of the rayon fibers used in Examples 1-3 and Comparative Examples 1-3. Although Examples 1-3 used the resin-impregnated rayon long fiber bundles of the first embodiment, the resin-impregnated rayon long fiber bundles of the second embodiment are in the form of tapes or sheets, making it easier to increase the impregnation rate compared to the resin-impregnated rayon long fiber bundles of the first embodiment. Therefore, it is obvious that a level of dispersibility equal to or better than that of Examples 1-3 can be obtained.

[0046] Example 4 Ten ISO dumbbell test pieces were obtained by injection molding the resin-impregnated rayon long fiber bundles (rayon long fiber reinforced resin composition) produced in Production Example 3. Injection molding was carried out as follows: (Injection molding conditions) Molding machine: ROBOSHOT α-S100iA manufactured by FANUC Corporation Cylinder temperature: 200℃ Mold temperature: 60℃ Screw diameter: 36mm Gate shape: Side gates connected to the ends of the dumbbell pieces, with gates the same size as the cross-section (4-10 mm) perpendicular to the longitudinal direction of the dumbbell piece.

[0047] Ten ISO dumbbell pieces were cut to a size of 80 × 10 × 4t, and both sides of the ten test pieces were visually inspected. The total number of fiber bundles that could be visually confirmed was counted. Using the ten ISO test pieces, the Charpy impact strength (kJ / m²) was measured in accordance with ISO 179 / 1eA. 2 ) was measured.

[0048] Furthermore, the fiber length in the molded product was measured and evaluated using the following method. One sample (0.6g) was wrapped in a 400-mesh stainless steel mesh, placed in a 200mL round-bottom flask, and 100mL of xylene was added. The resin was dissolved by setting the dryer to 145°C and heating the sample solution for more than 24 hours. The stainless steel mesh was lifted, and residual xylene was removed using a rotary evaporator set to 80°C. Then, the rayon fibers were extracted by heating them overnight in a dryer set to 155°C to remove the remaining xylene. A portion (500 strands) of the extracted rayon fibers was dispersed in water, and the weight-average fiber length was determined. The calculation formula used was from paragraphs 0044-0045 of Japanese Patent Publication No. 2006-274061. Number of fiber bundles visible to the naked eye / 10 strands: 3 (1.9 bundles / 100cm) 2 ) Weight-average fiber length (mm): 4.8 mm Charpy impact strength: 70 kJ / m 2 As described above, we were able to obtain molded products with a beautiful appearance and high impact strength.

[0049] Example 5 The resin-impregnated rayon long fiber bundles (rayon long fiber reinforced resin composition) produced in Production Example 4 were injection molded to obtain 10 plate test pieces measuring 50 × 90 × 3 mm. Injection molding was performed under the same conditions as in Example 1. The number of fiber bundles that could be visually confirmed was also determined using the same method as in Example 1. The number of fiber bundles that could be visually confirmed per four plates was 5, confirming excellent dispersibility. Comparative Examples 1-3 in Table 1 are plate test specimens of Manufacturing Example 2 using rayon fiber bundle 2 (TEX512, 2700 filaments). However, even when manufacturing resin-impregnated rayon long fiber bundles using TEX512 rayon fibers, by reducing the number of filaments in the rayon fiber bundle (for example, 1000-5000) and lowering the temperature of the crosshead die (for example, 200°C-260°C), it was possible to obtain resin-impregnated rayon long fiber bundles exhibiting similar dispersibility to Examples 1-3 in Table 1. [Industrial applicability]

[0050] Molded articles obtained from the rayon long fiber reinforced resin composition of this disclosure can be used in various fields such as electrical and electronic equipment, communication equipment, automobiles, building materials, sporting goods, and daily necessities.

Claims

1. A rayon long fiber reinforced resin composition comprising a resin-impregnated rayon long fiber bundle in which rayon fibers (A) are bundled together in a manner aligned in the length direction, and a thermoplastic resin (B) is impregnated and integrated with the continuous fibers, The number of filaments in the resin-impregnated rayon long fiber bundle is 1,000 to 10,000. A rayon long fiber reinforced resin composition wherein the rayon fiber content in the resin-impregnated rayon long fiber bundle is 5 to 70% by mass, and further, the impregnation rate of the thermoplastic resin in the resin-impregnated rayon long fiber bundle, determined by the following method, is 90% or more. <Impregnation Rate Test> 450 to 550 resin-impregnated rayon long fiber bundles, each cut to a length of 3 to 10 mm and having a circular or nearly circular cross-section, are used as samples. Immerse the sample in water (water-based pigment concentration 5% by mass) to which a water-based pigment (red) (product name SA-1 Aka, manufactured by Shachihata Co., Ltd.) has been added, at room temperature (20-30°C) for 2 minutes. After wiping off any water-based pigment adhering to the extracted sample, the sample's appearance is visually inspected. If visual inspection of the appearance is difficult, the sample can be divided into multiple sections along its length for further visual inspection, if necessary. A sample in which the aqueous pigment has continuously permeated from one end face to the other end face on the opposite side in the length direction is defined as a "resin-unimpregnated rayon long fiber bundle," and the impregnation rate of the thermoplastic resin is determined by the following formula. Impregnation rate (%) = (Total number of samples - Number of unimpregnated rayon fiber bundles) / Total number of samples × 100

2. A rayon long fiber reinforced resin composition comprising a resin-impregnated rayon long fiber bundle in which rayon fibers (A) are bundled together in a manner aligned in the length direction, and a thermoplastic resin (B) is impregnated and integrated with the continuous fibers, The number of filaments in the resin-impregnated rayon long fiber bundle is 1,000 to 10,000. A rayon long fiber reinforced resin composition wherein the rayon fiber content in the resin-impregnated rayon long fiber bundle is 5 to 70% by mass, and further, the impregnation rate of the thermoplastic resin in the resin-impregnated rayon long fiber bundle, determined by the following method, is 90% or more. <Impregnation Rate Test> 450 to 550 long fiber bundles of resin-impregnated rayon, cut into tape-like or sheet-like shapes with a width of 3 to 10 mm and a length of 5 to 10 mm, are used as samples. Immerse the sample in water (water-based pigment concentration 5% by mass) to which a water-based pigment (red) (product name SA-1 Aka, manufactured by Shachihata Co., Ltd.) has been added for 2 minutes at room temperature (20-30°C). After wiping off any water-based pigment adhering to the sample, the sample's appearance is visually inspected. A sample in which the aqueous pigment has continuously permeated from one end face to the other end face on the opposite side in the length direction is defined as a "resin-unimpregnated rayon long fiber bundle," and the impregnation rate of the thermoplastic resin is determined by the following formula. Impregnation rate (%) = (Total number of samples - Number of unimpregnated rayon fiber bundles) / Total number of samples × 100

3. The rayon long fiber reinforced resin composition according to claim 1 or 2, wherein the thermoplastic resin (B) is a polypropylene resin.

4. The rayon long fiber reinforced resin composition according to claim 1 or 2, wherein the thermoplastic resin (B) is selected from polyamide 6, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 1010, and polyamide MXD10.

5. The rayon long fiber reinforced resin composition according to claim 1 or 2, wherein the thermoplastic resin (B) is selected from biodegradable resins and biomass plastics.

6. The rayon long fiber reinforced resin composition according to any one of claims 1 to 5, wherein the rayon fiber (A) is 150 to 600 TEX.

7. A method for producing a rayon long fiber reinforced resin composition according to any one of claims 1 to 6. A method for producing a rayon long fiber reinforced resin composition, wherein a bundle of rayon fibers (A) is brought into contact with a molten thermoplastic resin (B), and the temperature range during which the bundle of rayon fibers (A) is impregnated with the molten thermoplastic resin (B) is in the range of 190°C to 300°C.

8. A molded article comprising the rayon long fiber reinforced resin composition according to any one of claims 1 to 6.

9. A molded article made from the rayon long fiber reinforced resin composition according to claim 8, wherein the weight-average fiber length of the rayon fibers contained in the molded article is 3 mm or more.

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