Fiber-reinforced recycled thermoplastic resin composition, molded article, and method for producing fiber-reinforced recycled thermoplastic resin composition

Abstract

To provide a fiber-reinforced recycled thermoplastic resin composition which exhibits excellent mechanical characteristics, and is excellent in moldability by apparently recycling breakage of a reinforcing fiber during recycling of the fiber-reinforced recycled thermoplastic resin composition.SOLUTION: A fiber-reinforced recycled thermoplastic resin composition is provided, obtained by blending 40 to 90 wt.% of a thermoplastic resin and 10 to 60 wt.% of a reinforcing fiber, wherein the thermoplastic resin contains a thermoplastic resin derived from a molded article recovered as a process scrap and / or a product after use, and the reinforcing fiber contains a reinforcing fiber Br having an oblateness of less than 2.0 and an irregular cross-section reinforcing fiber Bf having an oblateness of 2.0 or more, and has a weight ratio Br / Bf of 0.2 or more and 20.0 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to the recycling of waste plastics, and more particularly to a fiber-reinforced recycled thermoplastic resin composition that has an extremely small decrease in mechanical properties and excellent moldability compared to a fiber-reinforced thermoplastic resin composition that has not been recycled. The present invention relates to a fiber-reinforced recycled thermoplastic resin composition that has an excellent moldability and a very small decrease in mechanical properties compared to a fiber-reinforced thermoplastic resin composition that has not been recycled. [Background technology]

[0002] In recent years, there has been an increasing demand for recycling thermoplastic resins in order to realize a circular economy.

[0003] Thermoplastic resins are used as fiber-reinforced resin compositions by blending them with reinforcing fibers such as glass fibers and carbon fibers. However, in fiber-reinforced resin compositions, the reinforcing fibers are damaged during the molding and recycling processes, and recycled resin compositions (hereinafter referred to as recycled materials) have the problem of having lower mechanical properties than non-recycled resin compositions (hereinafter referred to as virgin materials). Therefore, it has been common to recycle virgin materials by mixing them with approximately 10 to 20% recycled materials.

[0004] In response to these problems, a method for improving the strength of recycled fiber-reinforced resin compositions has been proposed in which the crushed product of the recovered molded product generated during molding of the recycled resin composition is not pelletized but is instead melt-kneaded into a mixture containing a raw resin and a resin additive (see, for example, Patent Document 1). Also, a method for improving the strength of a recycled resin composition has been proposed by mixing a thermoplastic resin with a specific weight-average molecular weight or a long-fiber-reinforced thermoplastic resin composition (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-26719 A [Patent Document 2] International Publication No. 2023 / 2903 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the manufacturing method described in Patent Document 1 is a method for reducing the thermal history of the recovered molded product, and although it can prevent further breakage of the glass fibers in the recycled resin composition, it is difficult to say that it is a technology for recycling glass fibers that have already been broken and have deteriorated mechanical properties. In addition, Patent Document 2 does not describe the property recovery effect of modified cross-section reinforcing fibers. The present invention aims to obtain a fiber-reinforced recycled thermoplastic resin composition that exhibits excellent mechanical properties and has excellent moldability by apparently recovering the broken reinforcing fibers when recycling the fiber-reinforced thermoplastic resin composition. [Means for solving the problem]

[0007] Therefore, the inventors conducted intensive research to solve the above problems, and discovered that the above problems can be solved by mixing specific irregular cross-section reinforcing fibers with a recycled material containing a thermoplastic resin and reinforcing fibers, thereby arriving at the present invention.

[0008] That is, the present invention has the following configuration. 1. A fiber-reinforced recycled thermoplastic resin composition comprising (A) 40-90% by weight of a thermoplastic resin and (B) 10-60% by weight of reinforcing fibers, wherein the (A) thermoplastic resin comprises a thermoplastic resin derived from at least one selected from process waste materials of a fiber-reinforced thermoplastic resin composition comprising a thermoplastic resin and reinforcing fibers, and a molded product recovered after a molded product made of the fiber-reinforced thermoplastic resin composition is used as a product, and the (B) reinforcing fibers comprise reinforcing fibers Br having an aspect ratio of less than 2.0 (hereinafter, sometimes referred to as reinforcing fibers Br) and irregular cross-section reinforcing fibers Bf having an aspect ratio of 2.0 or more (hereinafter, sometimes referred to as irregular cross-section reinforcing fibers Bf), and the weight ratio Br / Bf of the reinforcing fibers Br and the irregular cross-section reinforcing fibers Bf contained in the fiber-reinforced recycled thermoplastic resin composition is 0.2 or more and 20.0 or less, 2. The fiber-reinforced recycled thermoplastic resin composition according to claim 1, characterized in that the ratio (Lw / Ln) of the weight average fiber length (Lw) to the number average fiber length (Ln) of the (B) reinforcing fiber is 1.30 or more and 3.00 or less. 3. The fiber-reinforced recycled thermoplastic resin composition according to claim 1 or 2, characterized in that the weight ratio Br / Bf of the (B) reinforcing fiber is more than 5.0 and 20.0 or less. 4. The fiber-reinforced recycled thermoplastic resin composition according to any one of items 1 to 3, characterized in that the (B) reinforcing fiber is at least one selected from glass fiber and carbon fiber. 5. The fiber-reinforced recycled thermoplastic resin composition according to any one of items 1 to 4, characterized in that the (A) thermoplastic resin contains at least one selected from polyphenylene sulfide, polyamide, polybutylene terephthalate, and liquid crystal polyester; 6. A molded article made of the fiber-reinforced recycled thermoplastic resin composition according to any one of items 1 to 5. 7. The molded article according to item 6, characterized in that the ratio (Lw / Ln) of the weight average fiber length (Lw) to the number average fiber length (Ln) of the (B) reinforcing fibers of the molded article is 1.30 or more and 3.00 or less. 8. A method for producing a fiber-reinforced recycled thermoplastic resin composition, comprising crushing at least one selected from process waste of a fiber-reinforced thermoplastic resin composition obtained by blending a thermoplastic resin and reinforcing fibers, and a molded product recovered after using a molded product made of the fiber-reinforced thermoplastic resin composition as a product, to obtain (X) crushed molded products, and mixing the (X) crushed molded products with (Y) substantially the same thermoplastic resin as the (X) crushed molded products (hereinafter, sometimes referred to as (Y) substantially the same thermoplastic resin), and (Z) irregular cross-section reinforcing fibers Bf having an aspect ratio of 2.0 or more (hereinafter, sometimes referred to as (Z) irregular cross-section reinforcing fibers Bf); 9. A method for producing a fiber-reinforced recycled thermoplastic resin composition according to item 8, characterized in that (Y) substantially the same thermoplastic resin and (Z) irregular cross-section reinforcing fiber Bf are melt-kneaded to obtain a (YZ) irregular cross-section fiber-reinforced thermoplastic resin composition, and then the (YZ) irregular cross-section fiber-reinforced thermoplastic resin composition and (X) crushed molded product are mixed; 10. The method for producing a fiber-reinforced recycled thermoplastic resin composition according to item 8 or 9, characterized in that the (X) crushed molded product is a crushed molded product pellet obtained by crushing process waste materials and / or molded products recovered after use as products, and then melt-kneading the crushed molded product pellets in an extruder; 11. The method for producing a fiber-reinforced recycled thermoplastic resin composition according to any one of items 8 to 10, characterized in that the reinforcing fibers constituting the (X) crushed molded article and / or the (Z) modified cross-section reinforcing fibers Bf are at least one selected from glass fibers and carbon fibers. 12. A method for producing a fiber-reinforced recycled thermoplastic resin composition described in any one of items 8 to 11, characterized in that the thermoplastic resin contains at least one selected from polyphenylene sulfide, polyamide, polybutylene terephthalate, and liquid crystal polyester. Effect of the Invention

[0009] The fiber-reinforced recycled thermoplastic resin composition obtained by the method of the present invention can be used in a wide range of fields such as injection molding, while retaining the same mechanical strength and moldability as when virgin materials are used, even after recycling. The fiber-reinforced recycled thermoplastic resin composition with these properties will be a material that contributes to the realization of a circular economy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will now be described in further detail.

[0011] The method for producing a fiber-reinforced recycled thermoplastic resin composition of the present invention is characterized by crushing at least one selected from process waste materials of a fiber-reinforced thermoplastic resin composition obtained by blending a thermoplastic resin and reinforcing fibers, and molded products made of the fiber-reinforced thermoplastic resin composition recovered after use as a product, to obtain (X) crushed molded products, and mixing the (X) crushed molded product with (Y) substantially the same thermoplastic resin as the (X) crushed molded product (hereinafter sometimes referred to as (Y) substantially the same thermoplastic resin), and (Z) irregular cross-section reinforcing fiber Bf having an aspect ratio of 2.0 or more.

[0012] In the present invention, "mixing" refers to melt-kneading each component with an extruder or the like. Representative examples of melt-kneading include a method of supplying raw materials to a commonly known melt-kneading machine such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll, and melt-kneading the raw materials. In order to suppress breakage of the reinforcing fibers and thermal deterioration of the thermoplastic resin, it is preferable to use a single-screw extruder or a twin-screw extruder having a screw configuration that can suppress breakage of the reinforcing fibers. In such a method, a fiber-reinforced recycled thermoplastic resin composition with small variation in each property can be obtained. Another example is pellet mixing of each component without melt-kneading. In such a method, breakage of the reinforcing fibers of the crushed molded product (X) can be suppressed, and a fiber-reinforced recycled thermoplastic resin composition with excellent properties can be obtained.

[0013] The process waste material used for the (X) crushed molded product is, for example, a process waste material generated in at least one process selected from a manufacturing process of a fiber-reinforced thermoplastic resin composition formed by blending a thermoplastic resin and a reinforcing fiber, and a molding process of a molded product made of the fiber-reinforced thermoplastic resin composition, and is, for example, a crushed product of a molded product molded by injection molding or the like, or a crushed product such as a sprue or runner recovered during injection molding. The fiber-reinforced thermoplastic resin may contain two or more types of fiber-reinforced thermoplastic resin. In addition, the (X) crushed molded product includes a crushed product obtained by crushing a molded product made of a fiber-reinforced thermoplastic resin composition and recovering it after use in the market as a product. From the viewpoint of realizing a circular economy, the (X) crushed molded product is preferably a crushed product obtained by crushing a molded product made of a fiber-reinforced thermoplastic resin composition and recovering it after use in the market as a product, and the molded product is more preferably composed of a fiber-reinforced recycled thermoplastic resin composition obtained by the manufacturing method of the present invention, and is particularly preferably a crushed product of a molded product that has been recycled multiple times.

[0014] (X) When the crushed molded products are crushed from molded products that have been collected after being used in the market as products, it is preferable to remove any attached substances by washing with water or an organic solvent either before or after crushing, from the viewpoint of suppressing deterioration of mechanical properties and odors due to contaminants.

[0015] (X) The crushed molded products are easy to handle if they are products made of resin material only, but in the present invention, insert molded products of resin and metal can be used if metal is removed. Also, a small amount of metal parts may be included, and in that case, since removing the metal parts during recovery reduces productivity, it is preferable to use a metal removal device in the manufacturing process of the crushed molded products. Specific examples of metal removal devices include a method in which metal is attached to a magnet and removed, and a magnetic or eddy current type sorting device.

[0016] The (X) crushed molded product may be pellets of crushed molded products obtained by crushing the molded products and then melt-kneading the crushed products, which is preferable because it improves classification during mixing and feedability to extruders and molding machines.

[0017] (X) The crushed molded products are preferably of a size that can be fed into an extruder or molding machine, and the major axis dimension of the pieces is preferably 1 to 10 mm or less.

[0018] (X) The thermoplastic resin constituting the crushed molded product is a resin that can be melted and solidified by heating and cooling reversibly, and specific examples thereof include vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol, polyvinyl acetal, polystyrene, AS resin, ABS resin, methacrylic resin, polyethylene, polypropylene, polyamide, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, liquid crystal polyester resin, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, polyether sulfone, polyetherimide, polyether ether ketone, fluororesin, thermoplastic elastomer, and copolymers thereof, as well as polymer alloys made of a plurality of these resins. In order to increase the fluidity during processing and suppress breakage of the reinforcing fibers, a crystalline resin is preferred, and it is more preferred to include any one selected from polyphenylene sulfide, polyamide, polybutylene terephthalate, and liquid crystal polyester, which are engineering plastics that are not easily deteriorated by the heat history associated with recycling.

[0019] (X) Examples of reinforcing fibers constituting the crushed molded product include glass fibers, carbon fibers, carbon nanotubes, carbon nanohorns, potassium titanate whiskers, zinc oxide whiskers, calcium carbonate whiskers, wollastonite whiskers, aluminum borate whiskers, as well as aramid fibers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, and metal fibers, and these can also be used in combination. In terms of availability, cost, and performance balance, it is preferable to use at least one selected from glass fibers and carbon fibers.

[0020] Furthermore, the surface of the reinforcing fiber is preferably pretreated with a coupling agent such as an epoxy compound, an isocyanate compound, an organic silane compound, an organic titanate compound, or an organic borane compound to improve the bundling property of the reinforcing fiber and the dispersibility when compounded with a resin. Such reinforcing fibers have improved adhesion and dispersibility at the interface with the thermoplastic resin, and can provide a high strength improvement effect, heat resistance, and chemical resistance.

[0021] The reinforcing fiber diameter is preferably 1 to 50 μm, more preferably 3 to 30 μm, and particularly preferably 5 to 20 μm. The smaller the reinforcing fiber diameter, the more improved the tensile strength and bending strength can be obtained, and the larger the fiber diameter, the less likely the fibers are to break during molding, and the more improved the mechanical properties can be obtained.

[0022] The reinforcing fibers may also include modified cross-section reinforcing fibers, which will be described later.

[0023] In the present invention, the substantially same thermoplastic resin (Y) refers to a thermoplastic resin having the same repeating unit as the thermoplastic resin constituting the crushed molded product (X), and it is effective to identify it by known spectroscopic analysis, elemental analysis, or thermal analysis. In addition, the combination of compatible thermoplastic resins is also substantially the same thermoplastic resin. "Compatible" refers to the behavior of forming a single phase when different thermoplastic resins are polymer-blended, and it is effective to identify it by known phase structure observation or the like. Furthermore, when the thermoplastic resin constituting the crushed molded product (X) is a polymer alloy, it is preferable that the substantially same thermoplastic resin (Y) is also a polymer alloy composed of the same thermoplastic resin as the polymer alloy of the crushed molded product (X).

[0024] The (Z) modified cross section reinforcing fiber Bf in the present invention is a reinforcing fiber having a flat cross section (hereinafter sometimes abbreviated as flat reinforcing fiber), and in the cross section when the reinforcing fiber is cut perpendicular to the length direction, the ratio of the major axis (the longest linear distance in the cross section) to the minor axis (the longest linear distance perpendicular to the major axis) (hereinafter sometimes referred to as the flatness) is 2.0 or more. The flatness is preferably 2.5 or more, more preferably 3.5 or more. There is no particular upper limit to the flatness, but it is preferably 8.0 or less, more preferably 6.0 or less, and particularly preferably 4.5 or less.

[0025] (Z) The irregular cross section reinforcing fiber Bf has a cross section with a major axis of preferably 10 μm or more, more preferably 20 μm or more, from the viewpoint of increasing the strength of the reinforcing fiber. The upper limit of the major axis is not particularly limited, but is preferably 80 μm or less, more preferably 45 μm or less. The minor axis of the cross section is preferably 2 μm or more, more preferably 5 μm or more. The upper limit of the minor axis is not particularly limited, but is preferably 20 μm or less, more preferably 15 μm or less.

[0026] The aspect ratio was determined by observing the reinforcing fibers with a scanning electron microscope, measuring the long and short diameters of the cross sections of 50 randomly selected reinforcing fibers, calculating the ratio, and then calculating the number average.

[0027] (Z) The modified cross section reinforcing fiber Bf may be glass fiber, carbon fiber, carbon nanotube, carbon nanohorn, potassium titanate whisker, zinc oxide whisker, calcium carbonate whisker, wollastonite whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber, metal fiber, etc., and it is also possible to use a combination of a plurality of types of these. In terms of the balance between cost and performance, it is preferable to use at least one selected from glass fiber and carbon fiber, and glass fiber is more preferable from the viewpoint of easily obtaining flat reinforcing fiber.

[0028] It is preferable that the surface of the (Z) modified cross section reinforcing fiber Bf is pre-treated with a coupling agent such as an epoxy compound, an isocyanate compound, an organic silane compound, an organic titanate compound, or an organic borane compound to improve the bundling property of the reinforcing fiber and the dispersibility when compounded with a resin. Such reinforcing fiber has improved adhesion and dispersibility at the interface with the thermoplastic resin, and can provide a high strength improvement effect, heat resistance, and chemical resistance.

[0029] From the viewpoint of recycling efficiency, it is preferable that the (Z) modified cross section reinforcing fiber Bf contains substantially the same reinforcing fiber as the (X) crushed molded product. Here, "substantially the same" means that the constituent elements and composition are the same, for example, reinforcing fibers within a range that can be treated as having the same composition, such as E glass. It is effective to identify these by known spectroscopic analysis, elemental analysis, or thermal analysis.

[0030] The amount of the crushed molded products (X) mixed in the fiber-reinforced recycled thermoplastic resin composition of the present invention is preferably 20% by weight or more, more preferably 30% by weight or more, and from the viewpoint of contributing to a circular economy, is further preferably 40% by weight or more, particularly preferably 50% by weight or more, and particularly preferably 70% by weight or more. Also, from the viewpoint of obtaining a fiber-reinforced recycled thermoplastic resin composition with excellent properties, the amount of the crushed molded products (X) mixed in is preferably 90% by weight or less.

[0031] In addition, the mixing amount of (Y) substantially the same thermoplastic resin and (Z) modified cross section reinforcing fiber Bf with an aspect ratio of 2.0 or more with respect to (X) crushed molded product is preferably such that the percentage of the difference between the ash content of the fiber reinforced recycled thermoplastic resin composition and the ash content of (X) crushed molded product divided by the ash content of (X) crushed molded product is -35% or more and 35% or less. Furthermore, in terms of suppressing changes in the quality of molded products obtained by molding the fiber reinforced recycled thermoplastic resin composition, the lower limit is preferably -20% or more, more preferably -15% or more, and particularly preferably -10% or more, and the upper limit is preferably 20% or less, more preferably 15% or less, and particularly preferably 10% or less. In addition, in terms of suppressing changes in moldability and realizing closed recycling, the lower limit is particularly preferably -5% or more, and the upper limit is particularly preferably 5% or less.

[0032] The ash content is a percentage obtained by dividing the weight of the residue obtained by baking the fiber-reinforced recycled thermoplastic resin composition or the crushed (X) molded article at 550°C for 3 hours by the weight before baking.

[0033] The method for producing a fiber-reinforced recycled thermoplastic resin composition in the present invention may include melt-kneading (Y) substantially the same thermoplastic resin and (Z) irregular cross-section reinforcing fibers Bf to obtain a (YZ) irregular cross-section fiber-reinforced thermoplastic resin composition, and then mixing the (YZ) irregular cross-section fiber-reinforced thermoplastic resin composition with (X) crushed molded product. Such a method is preferable because it produces a fiber-reinforced recycled thermoplastic resin composition with small variation in each property.

[0034] (YZ) Melt kneading of the irregular cross section fiber reinforced thermoplastic resin composition can be exemplified by a method in which raw materials are supplied to a commonly known melt kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll, and melt kneaded. In order to suppress breakage of the irregular cross section reinforcing fiber and thermal degradation of the thermoplastic resin, it is preferable to use a single-screw extruder or a twin-screw extruder with a screw configuration that can suppress breakage of the reinforcing fiber.

[0035] The fiber-reinforced recycled thermoplastic resin composition of the present invention is composed of 40 to 90% by weight of (A) thermoplastic resin and 10 to 60% by weight of (B) reinforcing fiber. The blending amount of (B) reinforcing fiber is preferably 20% by weight or more, more preferably 30% by weight or more, and even more preferably 40% by weight or more in order to obtain excellent strength.

[0036] The (A) thermoplastic resin in the present invention is a resin that can be melted and solidified by heating and cooling reversibly, and specific examples thereof include vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol, polyvinyl acetal, polystyrene, AS resin, ABS resin, methacrylic resin, polyethylene, polypropylene, polyamide, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, liquid crystal polyester resin, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, polyether sulfone, polyether imide, polyether ether ketone, fluororesin, thermoplastic elastomer, and copolymers thereof, as well as polymer alloys made of a plurality of these resins. In order to reduce the melt viscosity during processing and suppress breakage of the reinforcing fibers, a crystalline resin is preferred, and it is more preferred to be any one selected from polyphenylene sulfide, polyamide, polybutylene terephthalate, and liquid crystal polyester, which are engineering plastics that are not easily deteriorated by the heat history associated with recycling.

[0037] The (A) thermoplastic resin of the present invention contains a thermoplastic resin derived from at least one selected from process waste of a fiber-reinforced thermoplastic resin composition obtained by blending a thermoplastic resin and reinforcing fibers, and a molded product recovered after using a molded product made of the fiber-reinforced thermoplastic resin composition as a product. In addition, it is preferable that these thermoplastic resins are derived from the above-mentioned (X) crushed molded product. In addition, it is preferable that the (A) thermoplastic resin of the present invention contains the above-mentioned (Y) thermoplastic resin derived from substantially the same thermoplastic resin.

[0038] The fiber-reinforced recycled thermoplastic resin composition of the present invention contains (B) reinforcing fiber. (B) Reinforcing fiber contains reinforcing fiber Br with an aspect ratio of less than 2.0 and irregular cross-section reinforcing fiber Bf with an aspect ratio of 2.0 or more, and has a feature that the weight ratio Br / Bf of reinforcing fiber Br and irregular cross-section reinforcing fiber Bf in the fiber-reinforced recycled thermoplastic resin composition is 0.2 or more and 20.0 or less. The aspect ratio of reinforcing fiber Br is preferably 1.5 or less, and 1.0, that is, a reinforcing fiber with a circular cross section, is preferable from the viewpoint of efficiently recycling fiber-reinforced thermoplastic resin compositions that are widely distributed in the market. The aspect ratio of irregular cross-section reinforcing fiber Bf is preferably 2.5 or more, and more preferably 3.5 or more. There is no particular limit to the upper limit of the aspect ratio, but it is preferably 8.0 or less, more preferably 6.0 or less, and particularly preferably 4.5 or less.

[0039] The fiber-reinforced recycled thermoplastic resin composition of the present invention utilizes the fluidity due to the flat shape of the irregular cross-section reinforcing fiber Bf, the reinforcing effect in the direction perpendicular to the flow, and the characteristic that the fiber is not easily broken and the fiber length is easily left long, and not only recovers the properties of the fiber-reinforced thermoplastic resin composition in which the reinforcing fiber is broken and the reinforcing effect is lost due to recycling, but also exhibits properties that surpass the properties of unused materials. Therefore, it has a feature that the weight ratio Br / Bf is 0.2 or more and 20.0 or less, and the lower limit is preferably 1.0 or more, preferably 3.0 or more, and more preferably 5.0 or more from the viewpoint of reducing the amount of high-cost irregular cross-section reinforcing fiber Bf used, particularly preferably more than 5.0, and particularly preferably 8.0 or more. The upper limit is preferably 15.0 or less, more preferably 10.0 or less from the viewpoint of recovering the properties by the irregular cross-section reinforcing fiber Bf. (B) Reinforcing fiber is derived from (X) reinforcing fiber contained in crushed molded product or (Z) irregular cross-section reinforcing fiber Bf. Therefore, when producing a fiber-reinforced recycled thermoplastic resin composition, Br / Bf can be adjusted by changing the types and mixing amounts of (X) crushed molded products and (Z) irregular cross-section reinforcing fibers Bf.

[0040] In addition, Br / Bf can be obtained from the blending amounts of reinforcing fiber Br and irregular cross section reinforcing fiber Bf blended in the fiber-reinforced recycled thermoplastic resin composition. In order to calculate these blending amounts, if necessary, the fiber-reinforced recycled thermoplastic resin composition may be baked to extract the reinforcing fibers, and the blending amounts may be calculated from the number of reinforcing fibers Br and irregular cross section reinforcing fibers Bf in 100 randomly selected reinforcing fibers.

[0041] (B) Examples of reinforcing fibers include glass fibers, carbon fibers, carbon nanotubes, carbon nanohorns, potassium titanate whiskers, zinc oxide whiskers, calcium carbonate whiskers, wollastonite whiskers, aluminum borate whiskers, aramid fibers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, and metal fibers, and these can be used in combination. In terms of the balance between cost and performance, it is preferable to use at least one selected from glass fibers and carbon fibers, and glass fibers are more preferable in terms of easily obtaining modified cross section reinforcing fibers.

[0042] Furthermore, it is preferable that the surface of the (B) reinforcing fiber is pre-treated with a coupling agent such as an epoxy compound, an isocyanate compound, an organic silane compound, an organic titanate compound, or an organic borane compound to improve the bundling ability of the reinforcing fiber and the dispersibility when compounded with the resin. Such reinforcing fiber has improved adhesion and dispersibility at the interface with the thermoplastic resin, and can provide a high strength improvement effect, heat resistance, and chemical resistance.

[0043] The fiber-reinforced recycled thermoplastic resin composition of the present invention and the molded article made of the fiber-reinforced recycled thermoplastic resin composition have a wide fiber length distribution because of the mixture of (X) broken short reinforcing fibers derived from crushed molded articles and (Z) long reinforcing fibers derived from irregular cross-section reinforcing fibers Bf, and the fiber length distribution (Lw / Ln), which is the ratio of the weight average fiber length (Lw) to the number average fiber length (Ln) of the reinforcing fibers, is preferably 1.30 or more and 3.00 or less. As a result, it is easy to express the characteristics derived from long reinforcing fibers while maintaining the fluidity derived from short reinforcing fibers, and it is possible to favorably change the orientation of the reinforcing fibers, which not only improves the moldability and properties of the fiber-reinforced recycled thermoplastic resin composition, but also allows the expression of properties that surpass the properties of unused materials.

[0044] In the present invention, Lw / Ln cannot be generally stated because it depends on the type and amount of the (A) thermoplastic resin and (B) reinforcing fiber contained, but from the viewpoint of achieving both mechanical properties and fluidity, it is preferably 1.40 or more, and more preferably 1.50 or more. From the viewpoint of the quality stability of the molded product, Lw / Ln is preferably 2.50 or less, and more preferably 2.00 or less. Lw / Ln can be adjusted by changing the type and amount of the (X) crushed molded product and (Z) irregular cross-section reinforcing fiber Bf when producing the fiber-reinforced recycled thermoplastic resin composition.

[0045] The weight average fiber length (Lw) of the (B) reinforcing fiber of the fiber-reinforced recycled thermoplastic resin composition and the molded product made of the fiber-reinforced recycled thermoplastic resin composition is preferably 50 to 5000 μm from the viewpoint of ensuring excellent mechanical properties and fluidity, although it depends on the type of reinforcing fiber and cannot be generally stated. From the viewpoint of obtaining excellent mechanical properties, it is preferably 100 μm or more, more preferably 200 μm or more, and from the viewpoint of use as a metal replacement, it is even more preferably 300 μm or more. In addition, when Lw / Ln is in a preferred range, it is more preferable that it is 400 μm or more, and particularly preferable that it is 500 μm or more, since it is possible to achieve both mechanical properties and fluidity. In addition, from the viewpoint of obtaining excellent fluidity, it is preferably 4000 μm or less, more preferably 3000 μm or less, and particularly preferable that it is 2000 μm or less.

[0046] The fiber-reinforced recycled thermoplastic resin composition of the present invention has the fluidity due to the flat shape of the irregular cross-section reinforcing fibers Bf, and the characteristic that the fibers are less likely to break and tend to remain long. When the fiber-reinforced recycled thermoplastic resin composition is molded to obtain a molded product, breakage of the irregular cross-section reinforcing fibers is suppressed, making it possible to obtain a molded product with the above-mentioned preferred Lw and Lw / Ln.

[0047] Here, the weight average fiber length (Lw) and number average fiber length (Ln) of the (B) reinforcing fibers are values ​​obtained by baking the fiber-reinforced recycled thermoplastic resin composition pellets or a molded product obtained by molding the fiber-reinforced recycled thermoplastic resin composition pellets to remove the reinforcing fibers, observing the image magnified 50 to 100 times with an optical microscope, measuring the lengths of 1,000 randomly selected reinforcing fibers, and calculating the lengths based on the following formula using the measured values ​​(μm). Number average fiber length (Ln) = Σ(Li × ni) / Σni Weight average fiber length (Lw)=Σ(Li 2 ×ni) / Σ(Li×ni) Li: Fiber length of reinforcing fiber ni: Number of reinforcing fibers with fiber length Li.

[0048] The fiber-reinforced recycled thermoplastic resin composition of the present invention has excellent flowability due to the flat shape of the irregular cross-section reinforcing fiber Bf, and has a small anisotropy of molding shrinkage and excellent moldability due to the reinforcing effect in the perpendicular direction to the flow and the characteristic that the fiber length is easily left long and is not easily broken. Furthermore, the obtained molded product has a small anisotropy of dimensional characteristics. As a result, the fiber-reinforced recycled thermoplastic resin composition of the present invention has excellent heat cycle resistance. The heat cycle resistance is a characteristic that is determined by the number of treatments until cracks are observed in the insert molded product obtained by insert molding a thermoplastic resin into a metal block, which is treated under high temperature conditions (e.g., 130°C x 1 hour) and then under low temperature conditions (e.g., -40°C x 1 hour). This is an important characteristic value in automotive applications where resistance to severe temperature changes is required.

[0049] By adjusting the weight ratio Br / Bf, it is possible to adjust the moldability and heat cycle resistance, and it is possible to close-recycle the material for the same applications as virgin materials, or to develop properties that surpass those of virgin materials, enabling up-recycling.

[0050] The fiber-reinforced recycled thermoplastic resin composition of the present invention may contain, as a non-fiber filler, fullerene, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, asbestos, silicates such as alumina silicate, metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, and iron oxide, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and barium sulfate, hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, silica, and graphite, and these inorganic fillers may be hollow, and two or more types may be used in combination. In addition, these inorganic fillers may be pretreated with coupling agents such as isocyanate compounds, organic silane compounds, organic titanate compounds, organic borane compounds, and epoxy compounds before use. Among these, magnesium hydroxide, calcium carbonate, silica, and carbon black are preferred from the viewpoints of electrical properties, corrosion prevention, lubricating properties, and electrical conductivity.

[0051] The fiber-reinforced recycled thermoplastic resin composition of the present invention can be blended with ordinary additives such as phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, plasticizers such as organic phosphorus compounds, nucleating agents such as organic phosphorus compounds and polyether ether ketones, metal soaps such as montanic acid waxes, lithium stearate and aluminum stearate, release agents such as ethylenediamine-stearic acid-sebacic acid polycondensates and silicone compounds, as well as water, lubricants, ultraviolet inhibitors, colorants, and foaming agents. It is preferable to blend such additives in an amount of 0.01 to 5% by weight of the resin composition to the extent that the effects of the invention are not impaired.

[0052] The fiber-reinforced recycled thermoplastic resin composition of the present invention can be applied to various molding methods, such as extrusion molding, injection molding, blow molding, calendar molding, compression molding, vacuum molding, foam molding, blow molding, and rotational molding.

[0053] The fiber-reinforced recycled thermoplastic resin composition of the present invention can be used for many purposes, but is particularly preferably used for automobile components, where the demand for circular economy is increasing. EXAMPLES

[0054] The effects of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Evaluations in each of the examples and comparative examples were carried out by the following methods.

[0055] (1)Ash content The resin compositions obtained in each of the Reference Examples, Examples, and Comparative Examples were weighed, placed in a crucible, and fired for 3 hours in an electric furnace set at 550° C. to obtain a reinforcing fiber residue. The residue was weighed, and the weight ratio of the reinforcing fiber to the weight of the sample before firing was calculated to obtain the ash content.

[0056] (2) Density The resin compositions obtained in each of the Reference Examples, Examples, and Comparative Examples were used to determine the elastic modulus of elasticity in accordance with ISO1183 (2019) (unit: g / cm 3 ).

[0057] (3) Flow length measurement of resin composition The resin compositions obtained in each of the Examples and Comparative Examples were dried in a hot air dryer at 130°C for 3 hours, and molded using a Sumitomo Heavy Industries SE-30D injection molding machine and a 1mm thick (1mmt) spiral flow mold under the conditions of a cylinder temperature of 320°C, a mold temperature of 140°C, an injection speed of 230mm / sec, an injection pressure of 98MPa, an injection time of 5sec, and a cooling time of 15sec, and the flow length was measured (unit: mm). The larger this value, the better the flowability.

[0058] (4) Creating test pieces by injection molding The resin compositions obtained in each of the Examples and Comparative Examples were dried in a hot air dryer at 130°C for 3 hours, and then ISO (1A) dumbbell test pieces were injection molded using a Sumitomo Heavy Industries SE75-DUZ injection molding machine under conditions of a cylinder temperature of 310°C, a mold temperature of 140°C, and a screw rotation speed of 100 rpm.

[0059] (5) Mechanical properties The tensile properties of the ISO (1A) dumbbell test pieces obtained in (4) above were evaluated at 23°C using an autograph AG-Xplus 20kN testing machine in accordance with ISO 527-1,-2 (2012) under conditions of a support distance of 114 mm and a tensile speed of 5 mm / min.

[0060] Next, the bending properties were evaluated according to ISO178 (2010) at a support distance of 64 mm and a speed of 2 mm / min.

[0061] Next, the Charpy impact strength (with notch) was evaluated in accordance with ISO179 (2010) using test pieces obtained by cutting the ISO (1A) dumbbells obtained in the above item (4).

[0062] (6) Mold shrinkage rate The resin compositions obtained in each of the Examples and Comparative Examples were dried in a hot air dryer at 130°C for 3 hours, and then injection molded into 80 mm x 80 mm x 3 mm square plates using a Sumitomo Heavy Industries SE75-DUZ injection molding machine under conditions of a cylinder temperature of 310°C, a mold temperature of 140°C, and a screw rotation speed of 100 rpm.

[0063] Next, the dimensions of the obtained square plate in the resin flow direction (flow direction) and in the direction perpendicular to the flow direction (perpendicular direction) were measured with a vernier caliper and calculated based on the following formula. α = (L 0 -L / L 0 ) x 100 α: Molding shrinkage rate (%), L 0 : mold dimension (mm), L: molded product dimension (mm).

[0064] (7) Linear expansion coefficient Test pieces (10mm x 5mm x 3mm) were cut out from the center of the square plate molded product obtained in (6) above, with the resin flow direction (flow direction) and the direction perpendicular to the flow direction (perpendicular direction) as the longitudinal direction. After annealing at 200°C for 1 hr in air, the linear expansion coefficient of the test pieces in the longitudinal direction from -40°C to 150°C was measured using a thermomechanical analyzer (TMA) in accordance with ASTM D696. The smaller the linear expansion coefficient value and the closer the ratio of the resin flow direction (flow direction) to the direction perpendicular to the flow direction (perpendicular direction) is to 1.0, the smaller the anisotropy of the linear expansion change (low anisotropy) and the more excellent the dimensional stability.

[0065] (8) Fiber length analysis of reinforcing fibers The resin composition samples obtained in each Example and Comparative Example, and the ISO (1A) dumbbell test piece obtained in the above item (4) were cut to take a 1 cm square piece from the center, weighed as a sample, placed in a crucible, and fired for 3 hours in an electric furnace set at 550°C to obtain a reinforcing fiber residue. The residue was observed under an optical microscope at 50 to 100 times magnification, and the lengths of 1000 randomly selected reinforcing fibers were measured, and the measured values ​​(μm) were used to perform calculations based on the following formula. Number average fiber length (Ln) = Σ(Li × ni) / Σni Weight average fiber length (Lw)=Σ(Li 2 ×ni) / Σ(Li×ni) Li: Fiber length of reinforcing fiber ni: Number of reinforcing fibers with fiber length Li.

[0066] (9) Heat cycle resistance Using the resin compositions obtained in each of the Examples and Comparative Examples, a metal block (SUS430) was insert molded using a Sumitomo Heavy Industries SE75-DUZ injection molding machine under conditions of a cylinder temperature of 320°C and a mold temperature of 140°C to obtain a metal insert molded product. The obtained metal insert molded product was subjected to a thermal shock treatment, with one treatment being at 130°C for 1 hour and then at -40°C for 1 hour, and the occurrence of cracks was visually confirmed every 5 times. The number of thermal shock treatments at which cracks were observed was determined as heat cycle resistance. The more treatments until cracks occurred, the better the heat cycle resistance (thermal shock resistance) and the more preferable it was.

[0067] The raw materials used in each of the examples and comparative examples are shown below.

[0068] [Reference Example 1] (A-PPS-1) Polyphenylene sulfide resin In a 70-liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.63 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 0.513 kg (6.25 mol) of sodium acetate, and 3.82 kg of ion-exchanged water were charged, and the mixture was gradually heated to 245°C over about 3 hours while passing nitrogen through it at normal pressure. After distilling out 8.09 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mole of charged alkali metal sulfide.

[0069] After that, it was cooled to 200°C, 10.34 kg (70.32 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the temperature was raised from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm, and the reaction was carried out at 270°C for 140 minutes. Then, 2.67 kg (148.4 mol) of water was injected while cooling from 270°C to 250°C over 15 minutes. Then, it was gradually cooled from 250°C to 220°C over 75 minutes, and then quenched to near room temperature and the contents were removed.

[0070] The contents were diluted with about 35 liters of NMP, stirred at 85°C for 30 minutes as a slurry, and filtered through an 80 mesh wire mesh (opening 0.175 mm) to obtain a solid. The obtained solid was washed and filtered with about 35 liters of NMP in the same manner. The obtained solid was diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and filtered through an 80 mesh wire mesh to recover the solid. This operation was repeated three times in total. The obtained solid and 32 g of acetic acid were diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, filtered through an 80 mesh wire mesh, and the obtained solid was further diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and filtered through an 80 mesh wire mesh to recover the solid. The solid thus obtained was dried at 120°C under a nitrogen stream to obtain a dried PPS.

[0071] The resulting PPS resin (A-PPS-1) had a weight average molecular weight of 40,000.

[0072] (A-Ole-1) Olefin copolymer containing epoxy groups: Ethylene-glycidyl methacrylate copolymer (Sumitomo Chemical's "Bondfast" E) (A-Ole-2) Unmodified olefin copolymer: An ethylene-1-butene copolymer was used (Mitsui Chemicals' "Tafmer" A4085).

[0073] (Br-1) Glass fiber: Chopped glass bundled with an epoxy compound with a fiber length of 3 mm, a fiber diameter of 10.5 μm, and an aspect ratio of 1.0 was used (T-760H, manufactured by Nippon Electric Glass Co., Ltd.). (Bf-1) Flat glass fiber: Chopped glass bundled with an epoxy compound with a fiber length of 3 mm, a short diameter of 7 μm, a long diameter of 28 μm, and an aspect ratio of 4.0 was used (T-760FGF, manufactured by Nippon Electric Glass Co., Ltd.).

[0074] (C-1) Calcium carbonate was used as a non-fibrous filler (KSS-1000, manufactured by Kalfin Co., Ltd.)

[0075] (d-1) Organic silane compound containing an epoxy group: 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (Shin-Etsu Silicone: KBM303)

[0076] [Reference example 2] (X'-1) PPS resin composition (unused material) 65% by weight of PPS resin (A-PPS-1), 30% by weight of glass fiber (Br-1), 2.5% by weight of olefin polymer (A-Ole-1), 2.5% by weight of olefin polymer (A-Ole-2), and 0.3 parts by weight of organic silane compound (d-1) per 100 parts by weight of PPS resin, glass fiber, and olefin polymer were melt-kneaded at a cylinder temperature of 300°C and a screw rotation speed of 200 rpm using a Japan Steel Works TEX30α type twin-screw extruder (L / D=45, 3 kneading sections) equipped with a vacuum vent. The glass fiber was added by side feed, and the mixture was melt-kneaded to obtain a PPS resin composition (X'-1). The ash content was 30% by weight and the density was 1.52 g / cm. 3 It was.

[0077] [Reference Example 3] (X-1) Crushed molded product (X'-1) The PPS resin composition was dried in a hot air dryer at 130°C for 3 hours, and an ISO (1A) dumbbell test piece was injection molded using a Sumitomo Heavy Industries SE75-DUZ injection molding machine under the conditions of a cylinder temperature of 310°C, a mold temperature of 140°C, and a screw rotation speed of 100 rpm. The sprue / runner (corresponding to the molded product) generated during this process was crushed in a crusher so that the major axis dimension was 10 mm or less, and crushed molded product (X-1) was obtained. The ash content was 30% by weight, and the density was 1.52 g / cm. 3 It was.

[0078] [Reference Example 4] (X-2) Crushed molded product pellets The crushed molded product (X-1) was melt-kneaded using a Japan Steel Works TEX30α type twin-screw extruder (L / D=45, one kneading section) equipped with a vacuum vent at a cylinder temperature of 300°C and a screw rotation speed of 200 rpm to obtain crushed molded product pellets (X-2). The ash content was 30% by weight and the density was 1.52 g / cm. 3 It was.

[0079] [Reference Example 5] (YZ-1) Non-circular cross-section glass fiber reinforced PPS resin composition Except for using glass fiber (Bf-1) as the glass fiber, melt mixing was performed under the same conditions as in Reference Example 2 to obtain a modified cross section glass fiber reinforced PPS resin composition (YZ-1). The ash content was 30% by weight and the density was 1.52 g / cm. 3 It was.

[0080] [Reference Examples 2 to 5, Examples 1 to 4, Comparative Example 1] The raw materials were dry blended in the ratio shown in Table 1. The resulting resin composition was then subjected to the evaluations in the above items (1) to (8) to measure each of the properties.

[0081] [Example 5, Comparative Example 2] The raw materials were dry blended in the ratios shown in Table 1, and melt-kneaded in a Japan Steel Works TEX30α twin-screw extruder (L / D=45, one kneading section) equipped with a vacuum vent. The glass fibers were added by side feeding, and the mixture was melt-kneaded at a cylinder temperature of 300°C and a screw rotation speed of 200 rpm to obtain a resin composition. The resulting resin composition was then subjected to the evaluations in the above items (1) to (8) to measure each of the properties.

[0082] [Table 1]

[0083] [Table 2]

[0084] Comparison of the Reference Examples, Examples, and Comparative Examples in Tables 1 and 2 makes the following clear.

[0085] In comparison with Reference Example 2 (virgin material), the fiber-reinforced recycled thermoplastic resin composition obtained from the crushed molded products (X) in Reference Examples 3 and 4 exhibited a decrease in glass fiber length due to recycling, resulting in changes in moldability such as molding shrinkage rate (orthogonal direction) and flow length, an increase in the linear expansion coefficient (orthogonal direction) and anisotropy of the linear expansion coefficient, and a decrease in mechanical properties.

[0086] In Comparative Example 1, a fiber-reinforced recycled thermoplastic resin composition was obtained by mixing virgin material with pellets of crushed molded product (X) and having improved glass fiber length and various properties compared to Reference Example 4. However, it cannot be said to be equivalent to Reference Example 2 (virgin material), and the property recovery effect is insufficient.

[0087] In Examples 1 to 4, the weight ratio Br / Bf of the reinforcing fiber (B) of the fiber-reinforced recycled thermoplastic resin composition was increased by mixing the crushed molded product (X) and the pellets of the fiber-reinforced recycled thermoplastic resin composition (YZ), and a fiber-reinforced recycled thermoplastic resin composition with a high property recovery effect was obtained compared to Comparative Example 1. In addition, the mold shrinkage rate (perpendicular direction), fluidity, linear expansion coefficient (perpendicular direction), low anisotropy of the linear expansion coefficient, and Charpy impact strength derived from the irregular cross-section reinforcing fiber were large, and it was shown that these properties can be controlled by adjusting the weight ratio Br / Bf. In particular, as shown in Examples 3 to 4, it was shown that by making the weight ratio Br / Bf exceed 5.0, moldability and low anisotropy close to those of Reference Example 2 (unused material) can be obtained. A fiber-reinforced recycled thermoplastic resin composition having such characteristics is suitable for closed recycling in which it is molded in the same mold as the unused material.

[0088] Furthermore, a comparison of Reference Examples 2 to 3 with Comparative Example 2 and Example 5 showed that a similar property recovery effect was achieved even with a fiber-reinforced recycled thermoplastic resin composition obtained by melt-kneading (X) crushed molded product with (Y) substantially the same thermoplastic resin and (Z) irregular cross-section reinforcing fiber Bf.

[0089] [Reference Example 6] (A-PPS-2) Polyphenylene sulfide resin In a 70-liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.91 kg (69.80 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), and 10.5 kg of ion-exchanged water were charged, and the mixture was gradually heated to 245°C over about 3 hours while passing nitrogen through it at normal pressure. After distilling out 14.78 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mole of charged alkali metal sulfide.

[0090] The mixture was then cooled to 200°C, 10.48 kg (71.27 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the temperature was increased from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting for 100 minutes at 270°C, the bottom plug valve of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen, and most of the NMP was removed by stirring for a while at 250°C.

[0091] The obtained cake and 90 liters of ion-exchanged water were charged into an autoclave equipped with a stirrer, and acetic acid was added to adjust the pH to 7. After the inside of the autoclave was replaced with nitrogen, the temperature was raised to 192°C and maintained at that temperature for 30 minutes. The autoclave was then cooled and the contents were removed.

[0092] The contents were filtered with a glass filter under suction, and then 76 liters of ion-exchanged water at 70° C. was poured therein and filtered under suction to obtain a cake. The obtained cake was dried at 120° C. under a nitrogen stream to obtain a dried PPS.

[0093] The resulting PPS resin (A-PPS-2) had a weight average molecular weight of 25,000.

[0094] [Reference Example 7] (X'-2) PPS resin composition (unused material) 45% by weight of PPS resin (A-PPS-2), 30% by weight of glass fiber (Br-1), 2.5% by weight of olefin polymer (A-Ole-1), 2.5% by weight of olefin polymer (A-Ole-2), 20% by weight of calcium carbonate (C-1), and 0.3 parts by weight of organic silane compound (d-1) per 100 parts by weight of PPS resin, glass fiber, olefin polymer, and calcium carbonate were melt-kneaded at a cylinder temperature of 300°C and a screw rotation speed of 200 rpm using a Japan Steel Works TEX30α type twin-screw extruder (L / D=45, 3 kneading sections) equipped with a vacuum vent. The glass fiber was added by side feed, and the mixture was melt-kneaded to obtain a PPS resin composition (X'-2). The ash content was 50% by weight and the density was 1.67 g / cm. 3 It was.

[0095] [Reference Example 8] (X-3) Crushed molded product pellets Molded product crushed pellets (X-3) were obtained in the same manner as in Reference Examples 3 and 4, except that the PPS resin composition (X'-2) was used instead of the PPS resin composition (X'-1). The ash content was 50% by weight and the density was 1.67 g / cm. 3 It was.

[0096] [Reference Example 9] (YZ-2) Non-circular cross-section glass fiber reinforced PPS resin composition Except for using glass fiber (Bf-1) as the glass fiber, melt mixing was performed under the same conditions as in Reference Example 7 to obtain a modified cross section glass fiber reinforced PPS resin composition (YZ-2). The ash content was 50% by weight and the density was 1.67 g / cm. 3 It was.

[0097] [Reference Examples 7 to 9, Examples 6 to 10, Comparative Examples 3 to 5] The raw materials were dry blended in the ratio shown in Table 3. The resulting resin composition was then subjected to the evaluations in the above items (1) to (9) to measure each of the properties.

[0098] [Table 3]

[0099] [Table 4]

[0100] Comparison of the Reference Examples, Examples, and Comparative Examples in Tables 3 and 4 above makes the following clear, even when the molecular weight of the PPS resin is different or when a non-fibrous filler is blended.

[0101] In Examples 6 to 10, the weight ratio Br / Bf of the reinforcing fiber (B) of the fiber-reinforced recycled thermoplastic resin composition was increased compared to Comparative Examples 3 to 5 by mixing the crushed molded product (X) and the pellets of the fiber-reinforced thermoplastic resin composition (YZ). The mold shrinkage rate (perpendicular direction), low anisotropy of the mold shrinkage rate, fluidity, linear expansion coefficient (perpendicular direction), low anisotropy of the linear expansion coefficient, and characteristic recovery effect of Charpy impact strength derived from the irregular cross-section reinforcing fiber were observed, and it was shown that these characteristics can be controlled by adjusting the weight ratio Br / Bf. In particular, a remarkable improvement in heat cycle resistance was observed, and up-recycling was possible compared to Reference Example 7 (unused material). This is because the dimensional characteristics were improved, especially due to the decrease in the linear expansion coefficient and the decrease in anisotropy, which reduced the generation of load associated with the cold-heat test impact treatment. In addition, it was shown that by making the weight ratio Br / Bf exceed 5.0, moldability, low anisotropy, and heat cycle resistance close to Reference Example 7 (unused material) can be obtained, as shown in Examples 9 to 10. A fiber-reinforced recycled thermoplastic resin composition having such characteristics is suitable for closed recycling in which the composition is molded in the same mold as virgin material.

[0102] [Reference Example 10] (X'-3) PPS resin composition (unused material) 60% by weight of PPS resin (A-PPS-1), 40% by weight of glass fiber (Br-1), and 0.3 parts by weight of organic silane compound (d-1) were melt-kneaded using a Japan Steel Works TEX30α type twin-screw extruder (L / D=45, 3 kneading sections) equipped with a vacuum vent, with the glass fiber being fed by side feed, at a cylinder temperature of 300°C and a screw rotation speed of 200 rpm to obtain a PPS resin composition (X'-3). The ash content was 40% by weight and the density was 1.67 g / cm. 3 It was.

[0103] [Reference Example 11] (X-4) Crushed molded product pellets Molded product crushed pellets (X-4) were obtained in the same manner as in Reference Examples 3 and 4, except that the PPS resin composition (X'-3) was used instead of the PPS resin composition (X'-1). The ash content was 40% by weight and the density was 1.67 g / cm. 3 It was.

[0104] [Reference Example 12] (YZ-3) Non-circular cross-section glass fiber reinforced PPS resin composition Except for using glass fiber (Bf-1) as the glass fiber, melt mixing was performed under the same conditions as in Reference Example 10 to obtain a modified cross section glass fiber reinforced PPS resin composition (YZ-3). The ash content was 40% by weight and the density was 1.67 g / cm. 3 It was.

[0105] [Reference Examples 10 to 12, Examples 11 to 15, Comparative Examples 6 to 8] The raw materials were dry blended in the ratio shown in Table 5. The resulting resin composition was then subjected to the evaluations in the above items (1) to (8) to measure each of the properties.

[0106] [Table 5]

[0107] [Table 6]

[0108] By comparing the reference examples, examples and comparative examples in Tables 5 and 6 above, it is clear that the effects of the present invention can be obtained even when the amount of reinforcing fiber is different or when no olefin-based copolymer is added.

[0109] [Reference Example 13] (X-5) Crushed pellets of molded products with unknown composition ratio after use in the market From several water-related products that were collected after use in the market, several PPS resin compositions with unknown composition ratios printed as PPS-GF were removed and crushed in a crusher so that the major axis dimension was 10 mm or less. The crushed products were washed with 50°C hot water in a mesh drum type washing device and drained with air blow to obtain crushed molded products. Next, the crushed molded products were melt-kneaded at a cylinder temperature of 300°C and a screw rotation speed of 200 rpm using a Japan Steel Works TEX30α type twin-screw extruder (L / D = 45, one kneading section) equipped with a vacuum vent, and crushed molded product pellets (X-5) with a uniform composition were obtained. The ash content was 33% by weight and the density was 1.54 g / cm 3 In addition, the weight loss rate in air measured by thermogravimetric analysis showed that the polymer alloy contained approximately 3% by weight of olefin polymer and approximately 64% by weight of PPS.

[0110] [Reference Examples 2, 13, and Example 16] The raw materials were dry-blended in the ratios shown in Table 7. The resulting resin composition was then subjected to the evaluations in (1) to (8) above, and each characteristic was measured. It was found that the resin composition of Example 16 contained about 64.5% by weight of (A) PPS, about 4% by weight of an olefin-based elastomer, and 31.5% by weight of (B) reinforcing fibers.

[0111] [Table 7]

[0112] From Table 7 above, it is clear that the effects of the present invention can be obtained even if the (X) crushed molded article is a molded article that has been recovered after use as a product.

[0113] The effect of the present invention, which has been specifically described using these examples, is the property recovery effect derived from the irregular cross-section reinforcing fibers, so it is clear that the effect of the present invention can be obtained regardless of the type or amount of thermoplastic resin or reinforcing fiber.

Claims

1. A fiber-reinforced recycled thermoplastic resin composition comprising 40 to 90% by weight of (A) a thermoplastic resin and 10 to 60% by weight of (B) reinforcing fibers, wherein the (A) thermoplastic resin is derived from at least one selected from process waste materials of a fiber-reinforced thermoplastic resin composition comprising a thermoplastic resin and reinforcing fibers, and a molded product made of the fiber-reinforced thermoplastic resin composition and recovered after use as a product, and the (B) reinforcing fibers are reinforcing fibers Br (hereinafter, reinforcing fibers B) having an aspect ratio of less than 2.

0. (B) a fiber-reinforced recycled thermoplastic resin composition comprising reinforcing fibers Br and reinforcing fibers Bf having an aspect ratio of 2.0 or more (hereinafter sometimes referred to as reinforcing fibers Bf), the weight ratio Br / Bf of the reinforcing fibers Br and the reinforcing fibers Bf contained in the fiber-reinforced recycled thermoplastic resin composition being 0.2 or more and 20.0 or less, (B) a ratio (Lw / Ln) of the weight average fiber length (Lw) to the number average fiber length (Ln) of the reinforcing fibers being 1.30 or more and 3.00 or less, and (B) the reinforcing fibers are glass fibers.

2. The fiber-reinforced recycled thermoplastic resin composition according to claim 1, characterized in that the weight ratio Br / Bf of the (B) reinforcing fiber is more than 5.0 and 20.0 or less.

3. The fiber-reinforced recycled thermoplastic resin composition according to claim 1 or 2, characterized in that the (A) thermoplastic resin contains at least one selected from polyphenylene sulfide, polyamide, polybutylene terephthalate, and liquid crystal polyester.

4. A molded article made of the fiber-reinforced recycled thermoplastic resin composition according to claim 1 or 2.

5. The molded article according to claim 4, characterized in that the ratio (Lw / Ln) of the weight average fiber length (Lw) to the number average fiber length (Ln) of the reinforcing fibers (B) of the molded article is 1.30 or more and 3.00 or less.

6. At least one selected from process wastes of a fiber-reinforced thermoplastic resin composition obtained by blending a thermoplastic resin and reinforcing fibers, and a molded product made of the fiber-reinforced thermoplastic resin composition recovered after use as a product is crushed to obtain (X) crushed molded products, and the (X) crushed molded products, (Y) substantially the same thermoplastic resin as the (X) crushed molded products (hereinafter, sometimes referred to as (Y) substantially the same thermoplastic resin), and (Z) irregular cross-section reinforcing fiber Bf having an aspect ratio of 2.0 or more (hereinafter, sometimes referred to as (Z) irregular cross-section reinforcing fiber Bf) are melt-kneaded to obtain a (YZ) irregular cross-section fiber-reinforced thermoplastic resin composition, and then the (YZ) irregular cross-section fiber-reinforced thermoplastic resin composition and the (X) crushed molded products are mixed, and the reinforcing fiber and / or (Z) irregular cross-section reinforcing fiber Bf constituting the (X) crushed molded product are glass fibers.

7. The method for producing a fiber-reinforced recycled thermoplastic resin composition according to claim 6, characterized in that the (X) crushed molded product is a pellet of crushed molded product obtained by crushing process waste materials and / or molded products recovered after use as products, and then melt-kneading the crushed molded product in an extruder.

8. The method for producing a fiber-reinforced recycled thermoplastic resin composition according to claim 6 or 7, characterized in that the thermoplastic resin contains at least one selected from polyphenylene sulfide, polyamide, polybutylene terephthalate, and liquid crystal polyester.

Images