Resin composition, method for producing same, pellet, and molded article

Abstract

Provided are a resin composition capable of achieving a sufficient flexural modulus even when the ratio of a recycled material is increased, and a method for producing the resin composition.　A resin composition according to the present invention comprises a resin-impregnated fiber bundle (B-1) obtained by impregnating a fiber bundle in which a fibrous filler (B) is aligned in the longitudinal direction with a thermoplastic resin (A) which contains a recycled material (X) of a polypropylene-containing polyolefin resin, wherein: the polyethylene concentration in the recycled material (X) is less than 10 mass%; and the melting point of the recycled material (X) is 160-166°C. A production method according to the present invention comprises obtaining a resin-impregnated fiber bundle (B-1) by impregnating a fiber bundle in which a fibrous filler (B) is aligned in the longitudinal direction with a thermoplastic resin (A) which contains a recycled material (X) of a polypropylene-containing polyolefin resin, the recycled material (X) having a polyethylene concentration of less than 10 mass% and a melting point of 160-166°C.

Description

Resin composition, method for producing the same, pellets, and molded article

[0001] The present disclosure relates to a resin composition, a method for producing the same, pellets, and a molded article.

[0002] Polyolefin resins such as polypropylene and polyethylene are used in large amounts for various applications, and it is desired to reduce waste and effectively utilize resources through effective use of recycled materials including post-consumer products. In particular, polypropylene-containing polyolefin resins are widely used for food containers and packaging materials, so a large amount of such resins is recovered from the market, and development of resin compositions containing the polypropylene-containing polyolefin resin as a recycled material is in progress.

[0003] Meanwhile, polypropylene-containing polyolefin resins recovered from the market have a problem that mechanical properties such as flexural modulus are lower than those of homopolypropylene (PP homopolymer) and block copolymer (PP block copolymer). Therefore, when such a polyolefin resin is reused as a recycled material, it is necessary to improve mechanical properties such as flexural modulus. Patent Document 1 proposes a production method using recycled polypropylene without impairing mechanical properties by homogenizing multifilament strand pellets, which are a combination of recycled polypropylene and glass fibers, with virgin polypropylene.

[0004] International Publication No. 2023 / 123343

[0005] In the production method according to Patent Document 1, a large amount of virgin material is added to pellets of recycled material-containing multifilament strands to improve mechanical properties, so the proportion of recycled material contained in the resin composition is low. From the viewpoint of reducing waste and effectively utilizing resources, it is desirable to provide a fiber-reinforced resin composition that can achieve sufficient flexural modulus even when the proportion of recycled material is increased.

[0006] An object of the present disclosure is to provide a resin composition that can achieve sufficient flexural modulus even when the proportion of recycled material is increased, and a method for producing the same.

[0007] As a result of diligent research, the inventors of this application have found that the above problem can be solved by impregnating a fibrous filler with recycled polypropylene-containing polyolefin resin having a specific polyethylene concentration and melting point to form a resin-impregnated fiber bundle.

[0008] In other words, the present disclosure includes the following embodiments: [1] A resin composition comprising a resin-impregnated fiber bundle (B-1) in which a thermoplastic resin (A) containing a recycled polypropylene-containing polyolefin resin (X) is impregnated into a fiber bundle in which a fibrous filler (B) is aligned in the longitudinal direction, wherein the polyethylene concentration in the recycled material (X) is less than 10% by mass, and the melting point of the recycled material (X) is 160 to 166°C. [2] A method for producing a resin composition comprising a resin-impregnated fiber bundle, the method comprising impregnating a fiber bundle in which a fibrous filler (B) is aligned in the longitudinal direction with a thermoplastic resin (A) containing a recycled polypropylene-containing polyolefin resin (X) having a polyethylene concentration of less than 10% by mass and a melting point of 160 to 166°C, to obtain a resin-impregnated fiber bundle (B-1).

[0009] According to this disclosure, it is possible to provide a resin composition and a method for manufacturing the same that can achieve a sufficient flexural modulus even with a high proportion of recycled materials.

[0010] One embodiment of this disclosure will be described in detail below, but the scope of this disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of this disclosure. Each embodiment disclosed herein can be combined with any other features disclosed herein. If multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range. The lower and / or upper limits of the numerical ranges described herein may be replaced with numerical values ​​within that range, as shown in the examples. The expression "α to β" indicating a numerical range means "α or greater and β or less". If a particular description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments.

[0011] [Resin Composition] The first embodiment of this disclosure relates to a resin composition. The resin composition according to the first embodiment includes a resin-impregnated fiber bundle (B-1) in which a thermoplastic resin (A) containing a recycled polypropylene-containing polyolefin resin (X) is impregnated into a fiber bundle in which a fibrous filler (B) is aligned in the longitudinal direction, wherein the polyethylene concentration in the recycled material (X) is less than 10% by mass, and the melting point of the recycled material (X) is 160 to 166°C. According to the resin composition according to the first embodiment, a sufficient flexural modulus can be achieved even if the proportion of recycled material is high.

[0012] <Resin-Impregnated Fiber Bundle (B-1)> The resin composition according to the first embodiment includes a resin-impregnated fiber bundle (B-1). The resin-impregnated fiber bundle (B-1) is formed by impregnating a fiber bundle, in which fibrous filler (B) is aligned in the length direction, with a thermoplastic resin (A) containing recycled polypropylene-containing polyolefin resin (X). By including such a resin-impregnated fiber bundle (B-1) (hereinafter sometimes referred to as "fiber bundle (B-1)"), a resin composition can be made that can achieve sufficient mechanical properties even when the proportion of recycled material (X) is high. Hereinafter, in this specification, polypropylene-containing polyolefin resins recovered from the market in general will be referred to as "recycled material". Furthermore, "recycled material (X)" refers to recycled material that satisfies the above polyethylene concentration and melting point among the recycled material. Furthermore, "high proportion of recycled material" may also include a high proportion of recycled material and recycled material (X) in the resin components contained in the resin composition.

[0013] (Thermoplastic resin (A)) [Recycled material (X)] The fiber bundle (B-1) contains thermoplastic resin (A) containing recycled material (X) as an impregnation resin. The recycled material (X) has a polyethylene concentration of less than 10% by mass and a melting point of 160 to 166°C. When the inventors of the present invention evaluated the recycled material-containing resin composition, they noticed that there was variation in mechanical properties depending on the type of recycled material. When the inventors of the present invention investigated the cause of this, they found that the inclusion of a certain amount or more of ethylene in the recycled material tends to reduce the flexural modulus and high-temperature stiffness of the resulting recycled material-containing resin composition. Furthermore, the melting point of the recycled material is also important, and it was found that if the melting point of the recycled material is outside a certain range, it is difficult to achieve a sufficient flexural modulus even if the proportion of ethylene is low. If the melting point of the recycled material is too low, it becomes a factor that reduces the temperature of deflection under load (DTUL) of the resulting molded product, and mechanical properties such as the flexural modulus tend to decrease. Furthermore, recycled materials exhibit variations in melt viscosity, which is often higher than that of polypropylene, which is commonly used in long-fiber-containing thermoplastic resins. Therefore, it is considered difficult to reuse these recycled materials as impregnating resins for resin-impregnated fiber bundles. According to the resin composition and manufacturing method described herein, by successfully managing and selecting the recycled materials, it is possible to create a resin composition that can achieve a sufficient flexural modulus even with a high proportion of recycled materials. Specifically, the above problems can be solved by using recycled material (X) with a polyethylene concentration of less than 10% by mass and a melting point of 160 to 166°C, and by using this recycled material (X) as the impregnating resin for resin-impregnated fiber bundles. In addition, by adjusting the melt viscosity of the recycled material (X), the manufacturability of sufficient resin-impregnated fiber bundles can be ensured.

[0014] • Polyethylene concentration of recycled material (X) The polyethylene concentration of recycled material (X) can be measured by the following method. The polyethylene concentration in the recycled material (X) is determined by measuring the FT-IR (Fourier transform infrared spectroscopy) of the recycled material (X). Specifically, the FT-IR spectrum of the recycled material (X) is measured using an FT-IR analyzer under the following measurement conditions. (Measurement conditions) Measuring device: FT-IR analyzer (e.g., Thermo Fischer Scientific, product name "NICOLET iS50 FT-IR") Resolution: 4 cm －１ Number of measurements: 64 Measurement method: Transmission method Wavelength 695–750 cm in the spectrum －１ The polyethylene concentration of the recycled material (X) is determined from the proportion of band intensity derived from nearby polyethylene. The wavelength range is 695–750 cm. －１ If no peak is present (not detected) in the vicinity, the polyethylene concentration in the recycled material (X) is determined to be 0% by mass.

[0015] By using recycled material (X) with a polyethylene concentration of less than 10% by mass, a resin composition with minimal degradation of mechanical properties (especially flexural modulus) can be obtained. The polyethylene concentration mentioned above refers to the total amount of ethylene components derived from polyethylene (PE homopolymer), ethylene-propylene random copolymer, ethylene-propylene block copolymer, and other polymers in the recycled material (X).

[0016] In one embodiment, from the viewpoint of easily obtaining a molded product with less reduction in flexural modulus, the polyethylene concentration in the recycled material (X) is preferably 9% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less. In one embodiment, the polyethylene concentration in the recycled material (X) may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more. In a preferred embodiment, the polyethylene concentration in the recycled material (X) may be 0% by mass.

[0017] - Melting point of recycled material (X) The recycled material (X) shall have the above polyethylene concentration and a melting point of 160 to 166°C. The melting point of recycled material (X) can be determined by differential scanning calorimetry (DSC) at a heating rate of 10°C / min, in accordance with JIS K-7121.

[0018] In one embodiment, the melting point of the recycled material (X) may be greater than 160°C and less than or equal to 166°C, may be between 161°C and 166°C, may be between 162°C and 166°C, or may be between 163°C and 166°C.

[0019] • Polypropylene concentration of recycled material (X) The polypropylene concentration in recycled material (X) is preferably 90 to 100% by mass. The polypropylene concentration in recycled material (X) is the total amount of polypropylene units in PP homopolymer, PP block copolymer, and PP random copolymer. The polypropylene concentration is more preferably 91 to 100% by mass, even more preferably 93 to 100% by mass, and particularly preferably 95 to 100% by mass. In one embodiment, the polypropylene concentration may be 97 to 100% by mass or 100% by mass. The polypropylene concentration in recycled material (X) can be determined by measuring FT-IR. The specific measurement conditions are the same as those for measuring polyethylene concentration described above. In the spectrum, wavelength 780 to 920 cm －１ The polypropylene concentration of the recycled material (X) can be determined from the proportion of band strength derived from nearby polypropylene.

[0020] - Melt flow rate of recycled material (X) In one embodiment, the melt flow rate of recycled material (X) (230°C, 2.16 kg load) is preferably 10 to 200 g / 10 min, more preferably 20 to 150 g / 10 min, and even more preferably 30 to 90 g / 10 min, from the viewpoint of manufacturability of resin-impregnated fiber bundles. The melt flow rate of recycled material (X) (230°C, 2.16 kg load) can be measured based on ISO 1133 (condition D). The melt flow rate can also be measured using a melt flow rate tester (for example, "Melt Indexer L220" manufactured by Tateyama Science High Technologies Co., Ltd.).

[0021] The resin composition according to the first embodiment can achieve a sufficient flexural modulus even with a high proportion of recycled material. From the viewpoint of balancing various mechanical properties, the ratio of recycled material (X) to the total mass of thermoplastic resin (A) may be 20 to 100% by mass, 50 to 100% by mass, or 70 to 100% by mass.

[0022] [Other resins (a1)] The thermoplastic resin (A) may contain resin components other than the recycled material (X) (other resins (a1)). Other resins (a1) include, for example, homopolymers or copolymers of olefins having 2 to 6 carbon atoms (ethylene-based resins such as polyethylene and ethylene-propylene copolymers; poly(methylpentene-1); propylene-methylpentene copolymers, etc.); copolymers of olefins having 2 to 6 carbon atoms and copolymerizable monomers (ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, etc.); homopolymers or copolymers of cyclic olefins which may have substituents such as alkyl groups or ester groups (especially cyclic olefins condensed with hydrocarbon rings, bridged ring cyclic olefins, etc.) (for example, homopolymers of cyclic olefins such as polybicyclopentadiene and polynorbornene; copolymers of cyclic olefins selected from bicycloalkadienes, tricycloalkadienes, bicycloalkenes, and tricycloalkenes and α-olefins having 2 to 4 carbon atoms (ethylene, etc.)); and acid-modified products of homopolymers of olefins having 2 to 6 carbon atoms (for example, acid-modified polypropylene resins, preferably maleic acid and / or maleic anhydride-modified polypropylene). These may be used individually or in combination of two or more. The other resins may be virgin material or process waste material. They may also contain virgin polypropylene. "Process waste material" refers to thermoplastic resin waste generated during the manufacturing process (for example, discard shots from injection molding). From the viewpoint of adhesion between the fibrous filler and the thermoplastic resin, and the resulting improvement of the flexural modulus, it is preferable that the resin (a1) contains an acid-modified polypropylene resin, and more preferably a maleic acid and / or maleic anhydride-modified polypropylene resin.

[0023] When the thermoplastic resin (A) contains resin (a1), the proportion of resin (a1) in the thermoplastic resin (A) is preferably 5% by mass or less, and more preferably 4% by mass or less, relative to the total mass of the thermoplastic resin (A), from the viewpoint of easily achieving both a high recycling rate and mechanical properties. In one preferred embodiment, the thermoplastic resin (A) contains recycled material (X) and acid-modified polypropylene resin (a1) (more preferably maleic anhydride-modified polypropylene resin (a1)), where the proportion of recycled material (X) relative to the total mass of the thermoplastic resin (A) is 95 to 99% by mass, and the proportion of acid-modified polypropylene resin (a1) is 1 to 4% by mass.

[0024] In one embodiment, the melt flow rate of the thermoplastic resin (A) in the resin-impregnated fiber bundle (B-1) is preferably 50 to 800 g / 10 min, more preferably 55 to 500 g / 10 min, even more preferably 55 to 200 g / 10 min, and particularly preferably 60 to 200 g / 10 min. In one embodiment, the melt flow rate may be 200 to 800 g / 10 min, 300 to 600 g / 10 min, or 500 to 800 g / 10 min. If the melt flow rate of the thermoplastic resin (A) in the resin-impregnated fiber bundle (B-1) is within the above range, it becomes easier to suppress fiber breakage during the manufacturing of the resin-impregnated fiber bundle (B-1). The melt flow rate of the resin (A) in the resin-impregnated fiber bundle (B-1) is the value calculated by the simple melt viscosity measurement method described in Japanese Patent Application Publication No. 2009-128032. Specifically, the measurement can be performed under the following conditions. First, the resin-impregnated fiber bundle (B-1) is heated to 200°C and filtered through a SUS filter with a 100-mesh opening to collect only the thermoplastic resin (A). Next, 15 mg of the collected thermoplastic resin (A) is formed into a tablet with a diameter of 5 mm. This tablet is sandwiched between glass plates and melt-heated at 190°C for 5 minutes. Then, a 50 g weight is placed on top of the slide glass, and the diameter of the resulting circular film is measured to calculate the film area. The melt flow rate is calculated from the film area calculated above using a formula relating the area of ​​a film made from polypropylene with a known melt flow rate to the melt flow rate value.

[0025] (Fibrous Filler (B)) The resin-impregnated fiber bundle (B-1) contains a fibrous filler (B). Examples of fibrous fillers (B) (hereinafter sometimes simply referred to as "filler (B)") include fibrous inorganic fillers such as glass fibers, ceramic fibers, carbon fibers, zirconia fibers, alumina fibers, silica fibers, titanium oxide fibers, stainless steel fibers, metal fibers such as aluminum fibers and brass fibers, silicon carbide fibers, and rock wool; and fibrous organic fillers such as regenerated cellulose fibers. These may be used individually or in combination of two or more. Of these, from the viewpoint of availability, mechanical strength, and a form suitable for the manufacture of the resin-impregnated fiber bundle, it is preferable to include one or more selected from glass fibers, carbon fibers, and regenerated cellulose fibers. Furthermore, from the viewpoint of creating a resin composition with a lower environmental impact, it is preferable that the fibrous filler (B) contains regenerated cellulose fibers.

[0026] When the filler (B) contains glass fibers, the glass fibers are not particularly limited, and any known glass fibers are preferably used. In this disclosure, the type of glass is also not limited, but for quality reasons, E glass or corrosion-resistant glass containing zirconium elements in its composition is preferably used. Furthermore, glass fibers with a sizing agent attached to part or all of their surface may be used.

[0027] When the filler (B) contains carbon fibers, the carbon fibers are not particularly limited, and for example, PAN-based carbon fibers made from polyacrylonitrile, pitch-based carbon fibers made from pitch, etc., can be used.

[0028] The filler (B) may contain regenerated cellulose fibers. In this disclosure, "regenerated cellulose fibers" refers to cellulose fibers artificially spun using natural cellulose fibers (plant-derived cellulose fibers, animal-derived cellulose fibers (such as ascidian cellulose), and bacterial-derived cellulose fibers). If the filler (B) contains regenerated cellulose fibers, the regenerated cellulose fibers may include one or more selected from viscose-processed regenerated cellulose fibers, copper ammonia-processed regenerated cellulose fibers, and solvent-processed regenerated cellulose fibers.

[0029] The average diameter of the filler (B) is not particularly limited. In one embodiment, the average diameter may be 5 to 50 μm or 5 to 30 μm. The average diameter of the filler (B) refers to the average diameter of the filler (B) raw material before it is incorporated into the resin composition. This average diameter can be calculated using a scanning electron microscope and image processing software, and is the arithmetic mean measured over 10 filler (B) samples. Alternatively, a manufacturer's value (a value published by the manufacturer in their catalog, etc.) may be used.

[0030] In addition to the common circular shape, the cross-sectional shape of the filler (B) can also be a flattened shape. Specifically, examples include oval, cocoon shape (two circles in a pair), ellipse, semicircle, rectangle, square, other polygons, star shape, etc. Furthermore, the ratio of the longest diameter to the shortest diameter of the flattened cross-section is not particularly limited, but may be, for example, 1.5 to 6.0 or 2.0 to 5.0.

[0031] The number of filler (B) fibers in the fiber bundle (B-1) is preferably adjusted to a range of 100 to 30,000. In one embodiment, the number of filler (B) fibers in the fiber bundle (B-1) may be 2,000 to 30,000, 3,000 to 25,000, or 5,000 to 25,000. Here, "number of filler (B) fibers" refers to the number of monofilaments of the filler (B) (e.g., glass fibers).

[0032] The average length of the filler (B) in the fiber bundle (B-1) is preferably 5 to 30 mm. If the average length of the filler (B) in the fiber bundle (B-1) is 5 to 30 mm, a sufficient flexural modulus can be easily obtained even if the proportion of recycled material is high. The average length may be greater than 5 mm and less than or equal to 30 mm, or it may be between 5 and 20 mm, between 5 and 15 mm, or between 5 and 10 mm. The average length of the filler (B) in the fiber bundle (B-1) may also be calculated by measuring the length of the long axis of approximately 100 pellets in the fiber bundle (B-1) with a caliper or the like and taking the average value.

[0033] In the fiber bundle (B-1), the ratio of fibrous filler (B) to thermoplastic resin (A) is preferably such that the ratio of fibrous filler (B) is 5 to 70% by mass and the ratio of thermoplastic resin (A) is 30 to 95% by mass relative to the total mass of the fiber bundle (B-1). In one embodiment, when the fibrous filler (B) includes the above-mentioned fibrous inorganic filler, preferably it includes one or more selected from glass fibers and carbon fibers, the ratio of fibrous inorganic filler in the fiber bundle (B-1) is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 20 to 50% by mass. Furthermore, the ratio of thermoplastic resin (A) in the fiber bundle (B-1) is preferably 30 to 95% by mass, more preferably 40 to 90% by mass, and even more preferably 50 to 80% by mass.

[0034] In one embodiment, when the fibrous filler (B) contains regenerated cellulose fibers, the proportion of regenerated cellulose fibers in the fiber bundle (B-1) is preferably 15 to 60% by mass, more preferably 20 to 55% by mass, and even more preferably 25 to 50% by mass. Furthermore, the proportion of thermoplastic resin (A) in the fiber bundle (B-1) is preferably 40 to 85% by mass, more preferably 45 to 80% by mass, and even more preferably 50 to 75% by mass.

[0035] (Additives) The resin-impregnated fiber bundle (B-1) may contain additives other than the filler (B) and thermoplastic resin (A) described above, to the extent that they do not impede the effects of the present disclosure. Examples of additives include organic peroxides, softeners, surface lubricants, leveling agents, antioxidants, surfactants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, processing stabilizers, heat stabilizers, polymerization inhibitors, silane coupling agents, lubricants, plasticizers, crystallization accelerators, hydrolysis inhibitors, colorants, mold release agents, antistatic agents, metal powders, pigments, epoxy compounds, and the like. These additives may be used individually or in combination of two or more. These additives may also be contained within the fiber bundle (B-1), contained in the thermoplastic resin (A) which is the impregnation resin, or attached to at least a part of the surface of the resin-impregnated fiber bundle (B-1).

[0036] The resin composition according to the first embodiment may contain components other than the resin-impregnated fiber bundle (B-1). For example, it may contain the fiber bundle (B-1) and the aforementioned other resins. That is, it may contain the fiber bundle (B-1) and resin pellets of the other resin (for example, resin (a1)). However, from the viewpoint of ensuring uniformity of component dispersion in a workpiece produced by injection molding or the like, the resin composition may contain only the fiber bundle (B-1).

[0037] The resin composition according to the first embodiment is preferably prepared by the method for producing the resin composition according to the second embodiment described below.

[0038] [Method for Manufacturing Resin Composition] A second embodiment of the present disclosure relates to a method for manufacturing a resin composition. The manufacturing method according to the second embodiment is a method for manufacturing a resin composition comprising a resin-impregnated fiber bundle, the manufacturing method comprising impregnating a fibrous filler (B) aligned in the length direction with a thermoplastic resin (A) containing a recycled polypropylene-containing polyolefin resin (X) having a polyethylene concentration of less than 10% by mass and a melting point of 160 to 166°C, to obtain a resin-impregnated fiber bundle (B-1). According to the manufacturing method according to the second embodiment, a resin composition that can achieve a sufficient flexural modulus can be obtained even if the proportion of recycled material is high.

[0039] The manufacturing method according to the second embodiment may include preparing recycled material (X) and / or adjusting the melt flow rate of thermoplastic resin (A) before obtaining the resin-impregnated fiber bundle (B-1). Hereinafter, "preparing recycled material (X)" will be referred to as step (1), "adjusting the melt flow rate of thermoplastic resin (A)" as step (2), and "obtaining the resin-impregnated fiber bundle (B-1)" as step (3), and a preferred embodiment will be described.

[0040] <Step (1)> Step (1) is preparing a recycled material (X). Step (1) may be preparing a commercially available product of the recycled material (X), or may be selecting the recycled material (X) that has a polyethylene concentration of less than 1% by mass and a melting point of 160 to 166°C from recycled materials of polypropylene-containing polyolefin resins.

[0041] The method for selecting the recycled material (X) may include, for example, measuring FT-IR of the recycled material to determine the polyethylene concentration of the recycled material, and measuring the melting point of the recycled material. For the FT-IR measurement conditions and melting point measurement conditions of the recycled material, the method described in the first embodiment can be employed.

[0042] In one embodiment, step (1) may include adjusting the polyethylene concentration and melting point of the recycled material. For example, a recycled material having a low polyethylene concentration may be blended with a recycled material having a polyethylene concentration exceeding 10% by mass to adjust the polyethylene concentration to 10% by mass or less. The melting point may be adjusted by a similar method.

[0043] (Step (2)) Step (2) is adjusting the melt flow rate of the thermoplastic resin (A). In one embodiment, from the viewpoint of easily adjusting the melt flow rate of the thermoplastic resin (A) in the fiber bundle (B-1) to 50 to 800 g / 10 min, step (2) preferably includes adding an organic peroxide to the thermoplastic resin (A).

[0044] Examples of the organic peroxide include benzoyl peroxide, acetyl peroxide, di-t-butyl peroxide, t-butyl peroxylaurate, dicumyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene, 1,4-bis(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne-3, 2,5-di-t-butylperoxyhexane, t-butyl peroxybenzoate, n-butyl-4,4-bis-t-butylperoxyvalerate, octanoyl peroxide, p-menthane hydroperoxide, t-butylmaleic acid, and t-butyl peroxyacetate. These may be used alone singly, or two or more of them may be used in combination. Among these, 2,5-dimethyl-2,5-di-t-butylperoxyhexane is preferable.

[0045] From the viewpoint of easily adjusting the melt flow rate of the thermoplastic resin (A) in the fiber bundle (B-1) to 50 to 800 g / 10 min, the addition amount of the organic peroxide is preferably 0.005 to 0.25 parts by mass, more preferably 0.01 to 0.2 parts by mass, and still more preferably 0.02 to 0.1 parts by mass, relative to 100 parts by mass of the thermoplastic resin (A). In one embodiment, the proportion of the organic peroxide relative to the total mass of the resin-impregnated fiber bundle (B-1), in terms of solid content, may be 0.003 to 0.2 mass%, may be 0.007 to 0.2 mass%, or may be 0.01 to 0.15 mass%.

[0046] Furthermore, step (2) may involve adjusting the melt flow rate of the thermoplastic resin (A) to 55-500 g / 10 min, to 55-200 g / 10 min, or to 60-200 g / 10 min. In one embodiment, step (2) may involve adjusting the melt flow rate of the thermoplastic resin (A) to 200-800 g / 10 min, to 300-600 g / 10 min, or to 500-800 g / 10 min. The melt flow rate of the thermoplastic resin (A) can be measured under the same conditions as described in the first embodiment.

[0047] Step (2) may further include mixing the recycled material (X) with other resins (a1) and / or other additives (excluding organic peroxides).

[0048] <Step (3)> Step (3) involves impregnating a fiber bundle (B-1) with a fibrous filler (B) aligned in the length direction with a thermoplastic resin (A) containing recycled material (X). Step (3) can be performed, for example, by passing a fiber bundle (B) aligned in the length direction with a fibrous filler (B) through a crosshead die, and then supplying a molten mixture of thermoplastic resin (A) containing recycled material (X) from another extruder to the crosshead die to impregnate the fiber bundle with the thermoplastic resin (A). After that, the fiber bundle is shaped with a shaping nozzle at the outlet of the crosshead die, shaped with a shaping roll, and then cut to a predetermined length with a pelletizer to obtain a pellet-shaped resin-impregnated fiber bundle (B-1). The temperature during molten mixing is preferably 200 to 350°C, and more preferably 220 to 330°C. The average length of the resin-impregnated fiber bundle (B-1) obtained in step (3) is preferably 5 to 30 mm. The average length may be greater than 5 mm and less than or equal to 30 mm, or it may be between 5 and 20 mm, or between 5 and 15 mm. Furthermore, as the fibrous filler (B), one or more selected from glass fibers, carbon fibers, and regenerated cellulose fibers are preferred.

[0049] By the above process (3) or processes (1) to (3), a resin composition can be obtained that can achieve sufficient mechanical properties even with a high proportion of recycled material.

[0050] [Pellets] A third embodiment of this disclosure relates to pellets comprising the resin composition according to the first embodiment. The pellets according to the third embodiment can be obtained by manufacturing the resin composition by the manufacturing method according to the second embodiment.

[0051] [Molded Article and Method for Manufacturing the Same] The fourth embodiment in this disclosure relates to a molded article comprising a resin composition according to the first embodiment. The molded article according to the fourth embodiment is obtained by molding the resin composition according to the first embodiment (or pellets according to the third embodiment). The molded article according to the fourth embodiment may also be obtained by injection molding the resin composition according to the first embodiment (or pellets according to the third embodiment). The molded article according to the fourth embodiment can achieve a sufficient flexural modulus even with a high proportion of recycled material.

[0052] [Applications] The molded article according to the fourth embodiment can achieve a sufficient flexural modulus even with a high proportion of recycled material. Such molded articles can be suitably used, for example, as components for automobiles, home appliances, office furniture, and tools, as well as for tableware and racks themselves.

[0053] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure is disclosed below: [1] A resin composition comprising a resin-impregnated fiber bundle (B-1) in which a thermoplastic resin (A) containing a recycled polypropylene-containing polyolefin resin (X) is impregnated into a fiber bundle of a fibrous filler (B) aligned in the longitudinal direction, wherein the polyethylene concentration in the recycled material (X) is less than 10% by mass, and the melting point of the recycled material (X) is 160 to 166°C. [2] The resin composition according to [1], wherein the fibrous filler (B) comprises one or more selected from glass fibers, carbon fibers, and regenerated cellulose fibers. [3] The resin composition according to [1] or [2], wherein the thermoplastic resin (A) comprises an acid-modified polypropylene resin (a1). [4] The resin composition according to any one of [1] to [3], wherein the ratio of the fibrous filler (B) to the total mass of the resin-impregnated fiber bundle (B-1) is 5 to 70% by mass, and the ratio of the thermoplastic resin (A) is 30 to 95% by mass. [5] The resin composition according to any one of [1] to [4], wherein the average length of the fibrous filler (B) in the resin-impregnated fiber bundle (B-1) is 5 to 30 mm. [6] The resin composition according to any one of [1] to [5], wherein the melt flow rate of the thermoplastic resin (A) in the resin-impregnated fiber bundle (B-1) is 50 to 800 g / 10 min. [7] The resin composition according to any one of [1] to [6], wherein the ratio of the recycled material (X) to the total mass of the thermoplastic resin (A) is 20 to 100% by mass. [8] The resin composition according to any one of [1] to [7] for injection molding. [9] Pellets comprising the resin composition according to any one of [1] to [7]. A molded article comprising the resin composition described in any of [1] to [7].

[11] A method for producing a resin composition comprising a resin-impregnated fiber bundle, the method comprising impregnating a fibrous filler (B) aligned in the length direction with a thermoplastic resin (A) comprising a recycled polypropylene-containing polyolefin resin (X) having a polyethylene concentration of less than 10% by mass and a melting point of 160 to 166°C, to obtain a resin-impregnated fiber bundle (B-1).

[12] The manufacturing method according to

[11] , comprising preparing a recycled material (X) and / or adjusting the melt flow rate of the thermoplastic resin (A) before obtaining the resin-impregnated fiber bundle (B-1), wherein adjusting the melt flow rate of the thermoplastic resin (A) includes adding an organic peroxide to the thermoplastic resin (A).

[13] The manufacturing method according to

[11] or

[12] , wherein the fibrous filler (B) comprises one or more selected from glass fibers, carbon fibers, and regenerated cellulose fibers. Each configuration and combination thereof in each embodiment is an example, and additions, omissions, substitutions, and other modifications of the configuration can be made as appropriate without departing from the spirit of the present disclosure. The present disclosure is not limited by embodiments.

[0054] The present disclosure will be further illustrated by the following examples, but these examples will not limit the interpretation of the present disclosure.

[0055] <Materials> The following were used as raw materials for the resin composition. <Thermoplastic resin (A)> Six types of recycled materials were prepared as recycled materials of polypropylene-containing polyolefin resin. For each recycled material, the polyethylene concentration, melting point, and melt flow rate were measured under the conditions described later. Recycled materials with a polyethylene concentration of less than 10% by mass and a melting point of 160 to 166°C were designated as recycled materials (X1) to (X4). In addition, materials with polyethylene concentration and / or melting point outside the above range were designated as recycled materials 1 to 2.

[0056] • Recycled material (X1): Polyethylene concentration: 0% by mass, melting point: 165°C, melt flow rate (230°C, 2.16 kg load): 44 g / 10 min. • Recycled material (X2): Polyethylene concentration: 5.1% by mass, melting point: 164°C, melt flow rate (230°C, 2.16 kg load): 34 g / 10 min. • Recycled material (X3): Polyethylene concentration: 2.0% by mass, melting point: 164°C, melt flow rate (230°C, 2.16 kg load): 34 g / 10 min. • Recycled material (X4): Polyethylene concentration: 1.3% by mass, melting point: 163°C, melt flow rate (230°C, 2.16 kg load): 44 g / 10 min. • Recycled material 1: Polyethylene concentration: 10% by mass, melting point: 164°C, melt flow rate (230°C, 2.16 kg load): 53 g / 10 min. • Recycled material 2: Polyethylene concentration: 1.9% by mass, melting point: 158°C, melt flow rate (230°C, 2.16 kg load): 37 g / 10 min. • Resin (a1): Maleic anhydride modified polypropylene (manufactured by SK Functional Polymers, product name "OREVAC® CA100").

[0057] <Fibrous Filler (B)> ・Glass Fiber: Fiber bundles of glass fibers tied lengthwise (roving manufactured by Nippon Electric Glass Co., Ltd., product name "T-439N", average fiber diameter: 17 μm, count: 2400 tex). ・Regenerated Cellulose Fiber: Fiber bundles of solvent-regenerated cellulose fibers tied lengthwise (roving manufactured by BioMid Fiber, average fiber diameter (longest diameter): 11 μm). <Additives> ・Organic Peroxide: Masterbatch of organic peroxide (90% polypropylene, 10% 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, manufactured by Polytechs, product name "VMPP10X"). ・Antioxidant: Hindered phenol antioxidant (manufactured by BASF Japan Ltd., product name "Irganox® 1010FF"). - Processing stabilizer: Phosphorus-based processing stabilizer (manufactured by BASF Japan Ltd., product name "Irgafos® 168"). - Light stabilizer: Hindered amine-based light stabilizer (manufactured by BASF Japan Ltd., product name "Tinuvin® 111 FDL").

[0058] The polyethylene concentration, melting point, and melt flow rate of recycled materials (X1) to (X4) and recycled materials 1 to 2 were measured under the following conditions.

[0059] (Measurement of polyethylene concentration) The FT-IR spectrum of the recycled material was measured using an FT-IR analyzer under the following measurement conditions. (Measurement conditions) Measuring device: FT-IR analyzer (manufactured by Thermo Fischer Scientific, product name "NICOLET iS50 FT-IR") Resolution: 4 cm －１ Number of measurements: 64 Measurement method: Transmission method Wavelength 695–750 cm in the spectrum －１ The polyethylene concentration in the recycled material was determined from the proportion of band intensity derived from nearby polyethylene. The wavelength range was 695–750 cm. －１ If no peak is present (not detected) in the vicinity, the polyethylene concentration in the recycled material was determined to be 0% by mass.

[0060] (Measuring the melting point) Based on JIS K-7121, the melting point of the recycled material was determined by differential scanning calorimetry (DSC) under a heating rate of 10°C / min.

[0061] (Measurement of Melt Flow Rate) Based on ISO 1133 (Condition D), the melt flow rate of the recycled material (230°C, 2.16 kg load) was measured using a melt flow rate tester (manufactured by Tateyama Science High Technologies Co., Ltd., product name "Melt Indexer L220").

[0062] [Example 1] A thermoplastic resin (A) containing only 57.5% by mass of recycled material (X1), 2.1% by mass of resin (a1), 0.2% by mass of antioxidant, 0.1% by mass of light stabilizer, and 0.1% by mass of processing stabilizer was fed into a twin-screw extruder and melt-kneaded at a cylinder temperature of 280°C. Then, fiber bundles of filler (B) (glass fiber) were passed through a crosshead die and impregnated so that the proportion of filler (B) was 40% by mass and the proportion of thermoplastic resin (A) was 60% by mass. After that, the bundles were shaped using a shaping nozzle at the outlet of the crosshead die, shaped with a shaping roll, and then cut to a length of 9 mm using a pelletizer to obtain a resin composition consisting of strand-shaped resin-impregnated fiber bundles (B-1). The stability during the production of the resin composition (manufacturing stability) was evaluated according to the following evaluation criteria. (Manufacturing Stability Evaluation Criteria) Good: No fiber bundle breakage occurred in the crosshead die, allowing for continuous operation, and no fuzzing occurred at the nozzle due to trace amounts of fiber fragments. Acceptable: No fiber bundle breakage occurred in the crosshead die, allowing for continuous operation, but some fuzzing occurred at the nozzle due to trace amounts of fiber fragments. Unacceptable: Fiber bundle breakage occurred in the crosshead die, preventing continuous operation.

[0063] Next, the resin composition (pellets) of Example 1 was injection molded under the following conditions to obtain molded products (ISO tensile test specimens). Various mechanical properties and color evaluation of the obtained molded products were performed under the following conditions. (Molding conditions) Molding machine: Sumitomo Heavy Industries, Ltd., product name "SE100EV-A". Test specimen: ISO multipurpose test specimen type A. Molding temperature: 235°C. Mold temperature: 50°C.

[0064] <Evaluation of Mechanical Properties> - Measurement of Bending Strength and Bending Modulus of Elasticity Measurements were taken in accordance with ISO 178 using test specimens cut between the gauge marks of an ISO multipurpose test specimen. Specifically, measurements were taken using a bending tester (Bentograph II, manufactured by Toyo Seiki Seisakusho Co., Ltd.) under the following conditions: temperature: 23°C, test speed: 2 mm / min, and chuck distance (span) 64 mm.

[0065] - Measurement of load deflection temperature: Load deflection temperature was measured on ISO multipurpose test specimens in accordance with ISO 75-1 and 75-2. The bending stress was set to 1.8 MPa.

[0066] <Measurement of Melt Flow Rate of Thermoplastic Resin (A) in Resin-Impregnated Fiber Bundle (B-1)> First, the resin-impregnated fiber bundle (B-1) was heated to 200°C and filtered through a SUS filter with a 100-mesh opening to collect only the thermoplastic resin (A). Next, 15 mg of the collected thermoplastic resin (A) was formed into a tablet shape with a diameter of 5 mm. This tablet was sandwiched between glass plates and melted at 190°C for 5 minutes. Then, a 50 g weight was placed on top of the slide glass, and the diameter of the resulting circular film was measured, and the area of ​​the film was calculated. The melt flow rate was calculated from the area of ​​the film calculated above using a relationship formula between the area of ​​a film made from polypropylene with a known melt flow rate and the melt flow rate value.

[0067] [Examples 2, 4, 6, and Comparative Examples 1-2] Resin compositions consisting of resin-impregnated fiber bundles (B-1) were prepared under the same conditions as in Example 1, except that the materials shown in Table 1 were selected as the recycled material (X). The stability during the production of the resin composition (manufacturing stability) was evaluated using the same evaluation criteria as in Example 1. Next, various mechanical properties and the melt flow rate of the thermoplastic resin (A) in the fiber bundles (B-1) were measured for the obtained resin compositions under the same conditions as in Example 1. The results are shown in Table 1.

[0068] [Example 3] Recycled material (X1) and recycled material 1 were mixed in a ratio of 6:4 to obtain recycled material (X) with a polyethylene concentration of 4.1% by mass and a melting point of 165°C. A thermoplastic resin (A) containing only 57.5% by mass of this recycled material (X), 2.1% by mass of resin (a1), 0.2% by mass of antioxidant, 0.1% by mass of light stabilizer, and 0.1% by mass of processing stabilizer was fed into a twin-screw extruder and melt-kneaded at a cylinder temperature of 280°C. Then, fiber bundles of filler (B) (glass fiber) passed through a crosshead die were impregnated so that the proportion of filler (B) was 40% by mass and the proportion of thermoplastic resin (A) was 60% by mass. After that, the bundles were shaped with a shaping nozzle at the outlet of the crosshead die, shaped with a shaping roll, and then cut to a length of 11 mm with a pelletizer to obtain a resin composition consisting of strand-shaped resin-impregnated fiber bundles (B-1). The stability during the production of the resin composition (manufacturing stability) was evaluated using the same evaluation criteria as in Example 1. Next, various mechanical properties and the melt flow rate of the thermoplastic resin (A) in the fiber bundle (B-1) were measured for the obtained resin composition under the same conditions as in Example 1. The results are shown in Table 1.

[0069] [Example 5] A thermoplastic resin (A) containing only 57.21% by mass of recycled material (X3), 2.1% by mass of resin (a1), 0.29% by mass of organic peroxide, 0.2% by mass of antioxidant, 0.1% by mass of light stabilizer, and 0.1% by mass of processing stabilizer was fed into a twin-screw extruder and melt-kneaded at a cylinder temperature of 280°C. Then, fiber bundles of filler (B) (glass fiber) were passed through a crosshead die and impregnated with filler (B) at a ratio of 40% by mass and thermoplastic resin (A) at a ratio of 60% by mass. After that, the bundles were shaped using a shaping nozzle at the crosshead die outlet, shaped with shaping rolls, and then cut to a length of 11 mm using a pelletizer to obtain a resin composition consisting of strand-shaped resin-impregnated fiber bundles (B-1). The stability during the production of the resin composition (manufacturing stability) was evaluated using the same evaluation criteria as in Example 1. Next, the obtained resin composition was subjected to the same mechanical properties and the melt flow rate of the thermoplastic resin (A) in the fiber bundle (B-1) under the same conditions as in Example 1. The results are shown in Table 1.

[0070] [Examples 7, 10, and Comparative Examples 3, 5] Resin compositions consisting of resin-impregnated fiber bundles (B-1) were prepared under the same conditions as in Example 5, except that the recycled material (X) (or recycled material) was the material and composition shown in Table 1. The stability during the production of the resin composition (manufacturing stability) was evaluated using the same evaluation criteria as in Example 1. Next, various mechanical properties and the melt flow rate of the thermoplastic resin (A) in the fiber bundles (B-1) were measured for the obtained resin compositions under the same conditions as in Example 1. The results are shown in Table 1.

[0071] [Example 8] A thermoplastic resin (A) containing only 67.1% by mass of recycled material (X1), 2.1% by mass of resin (a1), 0.2% by mass of antioxidant, 0.1% by mass of light stabilizer, 0.1% by mass of processing stabilizer, and 0.34% by mass of organic peroxide was fed into a twin-screw extruder and melt-kneaded at a cylinder temperature of 260°C. Then, fiber bundles of filler (B) (regenerated cellulose fibers) were passed through a crosshead die and impregnated so that the proportion of filler (B) was 30% by mass and the proportion of thermoplastic resin (A) was 70% by mass. After that, the bundles were shaped using a shaping nozzle at the crosshead die outlet, shaped with shaping rolls, and then cut to a length of 7 mm using a pelletizer to obtain a resin composition consisting of strand-shaped resin-impregnated fiber bundles (B-1). The stability during the production of the resin composition (manufacturing stability) was evaluated using the same evaluation criteria as in Example 1. Next, the obtained resin composition was subjected to the same mechanical properties and the melt flow rate of the thermoplastic resin (A) in the fiber bundle (B-1) under the same conditions as in Example 1. The results are shown in Table 2.

[0072] [Example 9, Comparative Example 4] In Example 9, a resin composition consisting of resin-impregnated fiber bundles (B-1) was prepared under the same conditions as in Example 8, except that the material shown in Table 2 was selected as the recycled material (X) (or recycled material) and the proportion of organic peroxide was changed. In Comparative Example 4, a resin composition consisting of resin-impregnated fiber bundles (B-1) was prepared under the same conditions as in Example 8, except that the material shown in Table 2 was selected as the recycled material. The stability during the production of the resin composition (manufacturing stability) was evaluated using the same evaluation criteria as in Example 1. Next, various mechanical properties and the melt flow rate of the thermoplastic resin (A) in the fiber bundles (B-1) were measured for the obtained resin composition under the same conditions as in Example 1. The results are shown in Table 2.

[0073]

[0074]

[0075] As shown in Tables 1-2, the resin compositions of Examples 1-10 had a higher flexural modulus than the resin compositions of Comparative Examples 1-5. Furthermore, the resin compositions of Examples 5, 7, 8-10 also exhibited excellent manufacturing stability. Moreover, it was found that the resin compositions of the examples had sufficiently high flexural strength and their load deflection temperature did not decrease easily. From these results, it was confirmed that, according to the resin composition of the first embodiment and the manufacturing method of the second embodiment, a resin composition that can achieve a sufficient flexural modulus can be obtained even with a high proportion of recycled material.

[0076] The resin composition of this embodiment can achieve a sufficient flexural modulus even with a high proportion of recycled materials, and therefore can be suitably used in components of automobiles, home appliances, office furniture, and tools, as well as in tableware and racks themselves, thus possessing industrial applicability.

Claims

1. A resin composition comprising a resin-impregnated fiber bundle (B-1) in which a thermoplastic resin (A) containing a recycled polyolefin resin (X) is impregnated into a fiber bundle in which a fibrous filler (B) is aligned in the longitudinal direction, wherein the polyethylene concentration in the recycled material (X) is less than 10% by mass, and the melting point of the recycled material (X) is 160 to 166°C.

2. The resin composition according to claim 1, wherein the fibrous filler (B) comprises one or more selected from glass fibers, carbon fibers, and regenerated cellulose fibers.

3. The resin composition according to claim 1 or 2, wherein the thermoplastic resin (A) comprises an acid-modified polypropylene resin (a1).

4. The resin composition according to claim 1 or 2, wherein the ratio of the fibrous filler (B) to the total mass of the resin-impregnated fiber bundle (B-1) is 5 to 70% by mass, and the ratio of the thermoplastic resin (A) is 30 to 95% by mass.

5. The resin composition according to claim 1 or 2, wherein the average length of the fibrous filler (B) in the resin-impregnated fiber bundle (B-1) is 5 to 30 mm.

6. The resin composition according to claim 1 or 2, wherein the melt flow rate of the thermoplastic resin (A) in the resin-impregnated fiber bundle (B-1) is 50 to 800 g / 10 min.

7. The resin composition according to claim 1 or 2, wherein the ratio of the recycled material (X) to the total mass of the thermoplastic resin (A) is 20 to 100% by mass.

8. The resin composition according to claim 1 or 2, for use in injection molding.

9. A pellet comprising the resin composition according to claim 1 or 2.

10. A molded article comprising the resin composition according to claim 1 or 2.

11. A method for producing a resin composition containing a resin-impregnated fiber bundle, the method comprising impregnating a fibrous filler (B) with a resin-impregnated fiber bundle (B-1) by impregnating a thermoplastic resin (A) containing a recycled polypropylene-containing polyolefin resin (X) having a polyethylene concentration of less than 10% by mass and a melting point of 160 to 166°C with a fibrous filler (B) aligned in the length direction.

12. The manufacturing method according to claim 11, comprising preparing a recycled material (X) and / or adjusting the melt flow rate of the thermoplastic resin (A) before obtaining the resin-impregnated fiber bundle (B-1), wherein adjusting the melt flow rate of the thermoplastic resin (A) includes adding an organic peroxide to the thermoplastic resin (A).

13. The manufacturing method according to claim 11 or 12, wherein the fibrous filler (B) comprises one or more selected from glass fibers, carbon fibers, and regenerated cellulose fibers.

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