Thermoplastic resin composition and method for producing the same

Abstract

To provide a thermoplastic resin composition that sufficiently suppresses unpleasant odors during molding and exhibits excellent moldability. [Solution] A thermoplastic resin composition comprising a mixture of resin particles containing a thermoplastic resin (A) and eggshell powder (B), wherein the mass ratio of the thermoplastic resin (A) to the eggshell powder (B) is 98 / 2 to 20 / 80, the deodorant (C) is a metal-supported zeolite, and the content of the deodorant (C) is 0.05 to 0.80 parts by mass per 100 parts by mass of the total amount of the thermoplastic resin (A) and the eggshell powder (B).

Description

Technical Field

[0001] The present invention relates to a thermoplastic resin composition and a method for producing the same.

Background Art

[0002] Conventionally, a technique of using a thermoplastic resin together with eggshell powder has been known from the viewpoints of reducing resin cost and considering the environment (Patent Documents 1 to 5).

[0003] On the other hand, when using a thermoplastic resin together with eggshell powder, there has been a problem that a bad odor occurs during molding. Therefore, attempts have been made to use a thermoplastic resin together with a deodorant as well as eggshell powder (Patent Documents 6 to 8).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, with conventional technology, when thermoplastic resin was used together with eggshell powder and a deodorant, the unpleasant odor during molding could not be sufficiently suppressed, and further deodorization was required. Moreover, a new problem arose: reduced moldability during molding. Specifically, when the raw materials containing thermoplastic resin, eggshell powder, and deodorant were supplied from the hopper, the raw materials were not smoothly conveyed from the bottom of the hopper to the cylinder of the molding machine, resulting in reduced moldability.

[0006] The present invention aims to provide a thermoplastic resin mixture and a method for producing the same, which have sufficiently suppressed unpleasant odors during molding and excellent moldability. [Means for solving the problem]

[0007] The inventors of this invention have conducted extensive research to solve this problem and have found that the above objective can be achieved by using silver-supported zeolite as a deodorant and by mixing the eggshell-containing resin composition with the deodorant, rather than including the deodorant in the eggshell-containing resin composition. This led to the present invention.

[0008] The gist of this invention is as follows: <1> Resin particles containing thermoplastic resin (A) and eggshell powder (B); and Deodorizer (C) A thermoplastic resin composition which is a mixture containing, The mass ratio of the thermoplastic resin (A) / eggshell powder (B) is 98 / 2 to 20 / 80. The deodorant (C) is a metal-supported zeolite, A thermoplastic resin composition in which the amount of the deodorant (C) is 0.05 to 0.80 parts by mass per 100 parts by mass of the total amount of the thermoplastic resin (A) and the eggshell powder (B). <2> The resin particles are resin particles in which the eggshell powder (B) is dispersed in the thermoplastic resin (A). <1> The thermoplastic resin composition described above. <3> The thermoplastic resin (A) is a polyolefin, polyamide, or a mixture thereof. <1> or <2> The thermoplastic resin composition described above. <4> The thermoplastic resin (A) is polypropylene, polyethylene, or a mixture thereof. <1> ~ <3> A thermoplastic resin composition as described in any of the following. <5> The eggshell powder (B) is an uncalcined product. <1> ~ <4> A thermoplastic resin composition as described in any of the following. <6> The average particle size of the eggshell powder (B) is 10 to 70 μm. <1> ~ <5> A thermoplastic resin composition as described in any of the following. <7> The aforementioned metal-supported zeolite is a metal aluminosilicate salt. <1> ~ <6> A thermoplastic resin composition as described in any of the following. <8> The amount of the deodorant (C) is 0.15 to 0.50 parts by mass per 100 parts by mass of the total amount of the thermoplastic resin (A) and the eggshell powder (B). <1> ~ <7> A thermoplastic resin composition as described in any of the following. <9> The mass ratio of the thermoplastic resin (A) to the eggshell powder (B) is 97 / 3 to 85 / 15. <8> The thermoplastic resin composition described above. <10> A resin particle forming step of melting and kneading thermoplastic resin (A) and eggshell powder (B) to obtain resin particles; and Mixing step of mixing the resin particles and deodorant (C) to obtain a mixture A method for producing a thermoplastic resin composition containing the above. <11> The aforementioned mixture is a dry blend. <10> A method for producing the thermoplastic resin composition described above. <12> <1> ~ <9> A thermoplastic resin composition described in any of the following is produced: <10> or <11> A method for producing the thermoplastic resin composition described above. <13> <1> ~ <9> A molded article comprising any of the thermoplastic resin compositions described above. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a thermoplastic resin mixture in which unpleasant odors during molding are sufficiently suppressed and which has excellent moldability. [Modes for carrying out the invention]

[0010] [Thermoplastic resin composition] The thermoplastic resin composition of the present invention is resin particles containing a thermoplastic resin (A) and eggshell powder (B); and a metal-supported zeolite as a deodorant (C) is a mixture containing.

[0011] Specifically, the resin particles are resin particles in which the eggshell powder (B) is dispersed in the thermoplastic resin (A), and are an integrated product of the thermoplastic resin (A) and the eggshell powder (B). The resin particles may have a pellet form obtained by cutting a melt-kneaded product of the thermoplastic resin (A) and the eggshell powder (B) with a pelletizer after cooling, or may have a pulverized form obtained by pulverizing the melt-kneaded product after cooling. From the viewpoint of further improving deodorability and moldability, it is preferable that the resin particles have a pellet form obtained by cutting a melt-kneaded product with a pelletizer after cooling. The mixture described for the thermoplastic resin composition is a dry blend obtained by dry mixing. In the thermoplastic resin composition of the present invention, thus, separately from the resin particles in which the eggshell powder (B) is dispersed in the thermoplastic resin (A), by independently providing the deodorant (C), both deodorability and moldability can be improved. If not only the eggshell powder (B) but also the deodorant (C) is dispersed in the thermoplastic resin (A), sufficient deodorability cannot be obtained.

[0012] In this specification, deodorability is the property of suppressing odor (especially malodor) when molding using the thermoplastic resin composition. Moldability is the property that the time from when the thermoplastic resin composition enters the cylinder of the molding machine from the lower part of the hopper is shorter when molding using the thermoplastic resin composition, and can also be expressed as, for example, the transportability of the thermoplastic resin composition.

[0013] The size of the resin particles is not particularly limited. For example, the maximum size is usually 1 to 6 mm, particularly 1 to 5 mm. From the viewpoint of further improving deodorability and moldability, it is preferably 1.5 to 4.5 mm, more preferably 2.5 to 3.5 mm, and even more preferably 3 to 4 mm. When the resin particles have a cylindrical pellet shape, they may have an average diameter of 1 to 5 mm and a length of 2 to 5 mm. From the viewpoint of further improving deodorizing properties and moldability, they are preferably 1.5 to 4.5 mm in average diameter and 2.5 to 4.5 mm in length, more preferably 2 to 4 mm in average diameter and 3 to 4 mm in length, and even more preferably 2.5 to 3.5 mm and 3 to 4 mm in length.

[0014] In this specification, the maximum dimensions of resin particles are the average value of the maximum dimensions (maximum length) of any 10 resin particles. The average diameter and length of the resin particles are calculated using the average values ​​of the major and minor diameters of any 10 resin particles.

[0015] The thermoplastic resin (A) is not particularly limited as long as it is a polymer having thermoplastic properties, for example, polyolefins such as polypropylene and polyethylene; polycaproamide (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sevacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116), polyundecamamide (polyamide 11), polydodecamide (polyamide 12), polybis(4-aminocyclohexyl)methanedodecamamide (polyamide PACM12), polybis(3-methyl-4-aminocyclohexyl)methanedodecamamide (polyamide dimethyl PACM12), poly Examples include polyamides such as metaxylylene adipamide (polyamide MXD6), polynonameethylene terephthalamide (polyamide 9T), polydecamethylene terephthalamide (polyamide 10T), polyundecamethylene terephthalamide (polyamide 11T), and polyundecamethylene hexahydroterephthalamide (polyamide 11T(H)); polystyrene, AS resin, ABS resin, polyester resin, polycarbonate resin, elastomer; and mixtures thereof. From the viewpoint of further improving deodorizing properties and moldability, the thermoplastic resin (A) preferably contains polyolefins (especially polypropylene), polyamides (especially polyamide 6), or mixtures thereof, and more preferably contains polyolefins (especially polypropylene).

[0016] The molecular weight of the thermoplastic resin (A) is not particularly limited, but it is preferable that it has a molecular weight such that it has the following MFR (melt flow rate) or relative viscosity. For example, polyolefins are preferable to have a molecular weight such that they have the following MFR. Also, for example, polyamides are preferable to have a molecular weight such that they have the following relative viscosity.

[0017] The MFR of the thermoplastic resin (A) may be, for example, 0.3 to 50 g / 10 min, and from the viewpoint of further improving deodorizing properties and moldability, it is preferably 1 to 30 g / 10 min, more preferably 1 to 20 g / 10 min, and even more preferably 5 to 15 g / 10 min. This can be arbitrarily selected depending on the processing method of the thermoplastic resin composition.

[0018] In this specification, the MFR of thermoplastic resin (A) is the value measured under conditions of 230°C and 2.16 kg.

[0019] The relative viscosity of the thermoplastic resin (A) may be, for example, 1.8 to 4.0, and is preferably 2.0 to 3.0 from the viewpoint of further improving deodorizing properties and moldability. It can be arbitrarily selected depending on the processing method of the thermoplastic resin composition.

[0020] In this specification, the relative viscosity of thermoplastic resin (A) is expressed as the ratio of the falling time to the falling time of the solvent alone, measured at a temperature of 25°C using an Ubbelohde viscometer for a sample solution with a concentration of 1 g / dL dissolved in 96% sulfuric acid.

[0021] Thermoplastic resin (A) is available commercially. For example, as polypropylene, Prime Polymer's J-700GP (MFR=8g / 10min) can be used. For example, Unitika's A1030SR (PA6) (relative viscosity = 2.5) can be used as a polyamide.

[0022] Eggshell powder (B) may be calcium carbonate, but from an environmental perspective (for example, from the viewpoint of effective utilization of waste), it is preferable to use powder made from discarded eggshells (e.g., chicken eggshells). Furthermore, using eggshell powder (B) can cause unpleasant odors during molding, but since the present invention has excellent deodorizing properties, it is effective to use eggshell powder (B) in this invention.

[0023] The eggshell powder (B) may be unfired or fired. From the viewpoint of effectively exhibiting the effects of the present invention (particularly the effect of improving deodorizing properties), it is preferable that the eggshell powder (B) be unfired. This is because even when using unfired eggshell powder, not much unpleasant odor is generated during molding.

[0024] The average particle size of the eggshell powder (B) is not particularly limited and may be, for example, 5 to 100 μm, but is preferably 10 to 70 μm, more preferably 10 to 50 μm, and even more preferably 15 to 30 μm, from the viewpoint of further improving deodorizing properties and moldability.

[0025] The average particle size of eggshell powder (B) is measured using laser diffraction. The average particle size of eggshell powder (B) can also be measured using other methods such as dynamic light scattering, sieving, and electron microscopy (SEM / TEM).

[0026] Eggshell powder (B) is available commercially. For example, GT-29 (average particle size = 15 μm) (unfired) manufactured by Green Techno 21, and Ranran Buster 10 (average particle size = 10 μm) (fired) manufactured by ESC can be used.

[0027] The ratio of thermoplastic resin (A) to eggshell powder (B) is 98 / 2 to 20 / 80 by mass ratio of thermoplastic resin (A) to eggshell powder (B). From the viewpoint of further improving deodorizing properties and moldability, it is preferably 98 / 2 to 30 / 70, more preferably 98 / 2 to 40 / 60, even more preferably 98 / 2 to 45 / 55, sufficiently preferably 98 / 2 to 55 / 45, even more sufficiently preferably 98 / 2 to 60 / 40, even more sufficiently preferably 97 / 3 to 70 / 30, and most preferably 97 / 3 to 85 / 15. If the content ratio of thermoplastic resin (A) is too low, it becomes difficult to manufacture resin particles. If the content ratio of thermoplastic resin (A) is too high, the contribution of eggshell powder (B) to environmental considerations is significantly reduced.

[0028] Deodorizer (C) contains metal-supported zeolite. Metal-supported zeolite is zeolite on which metal (or metal ions) is supported (or captured). If deodorizer (C) does not contain metal-supported zeolite, sufficient deodorizing effect cannot be obtained, even if other deodorizers are included.

[0029] Metal-supported zeolites are crystalline materials of metal aluminosilicate salts. Such metal-supported zeolites may be natural zeolites, synthetic zeolites, or mixtures thereof.

[0030] Examples of natural zeolites that can be used as metal-supported zeolites include clinoptilolite, mordenite, rhodochrolite, natrolite, gonnaldite, eddingtonite, analusim, leucite, yugawaralite, gismondine, poringite, phillipsite, chabazite, erionite, hojasite, ferrielite, mutinaite, chernihiite, heulandite, stilbite, koulesite, berylosilicate (logianite, shanhalite, etc.), and zincosilicate (gaultite). Examples of synthetic zeolites that can be used as metal-supported zeolites include A-type zeolite, X-type zeolite, Y-type zeolite, L-type zeolite, beta-type zeolite, ferrielite, mordenite, ofretite, chabazite, MCM-22, ZSM-5, ZSM-11, and SAPO-11. Synthetic zeolites may also be artificial zeolites.

[0031] Examples of metals supported in metal-supported zeolites include zinc, tin, iron, platinum, palladium, titanium, silver, copper, manganese, and cobalt. From the viewpoint of further improving deodorizing properties and moldability, the metal supported in the metal-supported zeolite preferably contains zinc (especially zinc ions) and / or silver (especially silver ions), and more preferably contains zinc (especially zinc ions).

[0032] Metal-supported zeolites may contain cations in their skeletal structure in addition to the supported metal (or metal ion). Examples of such cations include hydrogen ions, ammonium ions, alkyl-substituted ammonium ions, aryl or aralkyl-substituted ammonium ions, alkali metal ions, alkaline earth metal ions, metal ions, and gallium ions. Only one type of cation may be used, or two or more types may be used in combination. The content of such cations in the zeolite is not particularly limited. Examples of alkyl-substituted ammonium ions include methylammonium ions, dimethylammonium ions, trimethylammonium ions, and tetramethylammonium ions. Alkali metal ions that may be included in the skeletal structure of metal-supported zeolites may be selected from lithium ions, sodium ions, and potassium ions. Alkaline earth metal ions that may be included in the skeletal structure of metal-supported zeolites may be selected from magnesium ions, calcium ions, and barium ions. The metal ions that may be included as cations in the skeletal structure of the metal-supported zeolite may be selected from zinc ions, tin ions, iron ions, platinum ions, palladium ions, titanium ions, silver ions, copper ions, manganese ions, and cobalt ions, etc.

[0033] The average particle size of the metal-supported zeolite is preferably 0.01 to 5 μm, more preferably 0.05 to 4 μm, more preferably 0.1 to 3 μm, and even more preferably 1 to 2 μm, from the viewpoint of further improving deodorizing properties and moldability.

[0034] The average particle size (D50) of the metal-supported zeolite is measured using dynamic light scattering. The average particle size (D50) of the metal-supported zeolite can also be measured using other methods such as laser diffraction, sieving, and electron microscopy (SEM / TEM).

[0035] The specific surface area of ​​metal-supported zeolite is 100 m². 2It is preferable that the amount be 1 / g or more, and from the viewpoint of further improving deodorizing properties and moldability, it is preferably 300m 2 It is 1 / g or more.

[0036] The specific surface area of ​​the metal-supported zeolite is measured using the BET method with nitrogen gas.

[0037] Metal-supported zeolites are available commercially. For example, PurgeLite (formerly known as DashLite) ZH manufactured by Sinanen Zeomic Co., Ltd. can be used.

[0038] The content of the deodorant (C) (i.e., metal-supported zeolite) is 0.05 to 0.80 parts by mass per 100 parts by mass of the total amount of thermoplastic resin (A) and eggshell powder (B), preferably 0.15 to 0.65 parts by mass, and more preferably 0.15 to 0.50 parts by mass, from the viewpoint of further improving deodorizing properties and moldability. If the content of the deodorant (C) is too low, the deodorizing properties will decrease. If the content of the deodorant (C) is too high, the moldability will decrease.

[0039] The thermoplastic resin composition of the present invention may contain additives such as antioxidants, lubricants, dyes and pigments, flow improvers, flame retardants, impact resistant agents, and lightfast agents. These additives may be independently contained inside the resin particles or outside the resin particles.

[0040] The content of the additive is 20% by mass or less, preferably 10% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on the total amount of resin particles containing the additive. If two or more types of the additive are included, their total content should be within the above range.

[0041] [Method for producing thermoplastic resin compositions] The thermoplastic resin composition of the present invention can be manufactured by a manufacturing method comprising the following steps: A resin particle forming step of melting and kneading thermoplastic resin (A) and eggshell powder (B) to obtain resin particles; and A mixing step of mixing resin particles and a deodorant (C) to obtain a mixture.

[0042] The resin particle formation process is not particularly limited as long as the aforementioned resin particles are formed. For example, a molten mixture of thermoplastic resin (A) and eggshell powder (B) may be cooled and solidified, and then cut with a pelletizer. Alternatively, for example, the molten mixture may be cooled and solidified, and then pulverized in a pulverizer.

[0043] Melting and mixing are typically carried out using an extruder / mixer. The melting temperature is not particularly limited as long as the thermoplastic resin (A) melts. For example, in the case of polyamide 6, it may be 240-270°C, and especially 250-260°C. Also, in the case of polypropylene, it may be 170-200°C, and especially 175-190°C.

[0044] In the mixing step, the resin particles obtained in the resin particle formation step are mixed with the deodorant (C). The mixing is usually dry mixing, and may be a so-called dry blend. The mixing method is not particularly limited as long as the deodorant (C) is sufficiently and uniformly mixed with the resin particles, and for example, a known mixer may be used. Accordingly, the thermoplastic resin composition of the present invention has the form of mixed particles (dry blend) of resin particles and deodorant (C) particles. Depending on the relationship between the particle sizes of the resin particles and the deodorant (C) particles, the deodorant (C) particles may adhere to the surface of the resin particles, or the resin particles may adhere to the surface of the deodorant (C) particles.

[0045] [Molded body] The present invention also provides molded articles. The molded article of the present invention is a molded article manufactured using the thermoplastic resin composition of the present invention described above, and is a molded article containing the thermoplastic resin composition. The molded article of the present invention may also be a molded article of the thermoplastic resin composition of the present invention described above.

[0046] The thermoplastic resin composition of the present invention effectively suppresses unpleasant odors during molding, and therefore, by using it in the same manner as conventional thermoplastic resins, the effects of the present invention can be effectively realized. The thermoplastic resin composition of the present invention can be widely used in molded parts such as general merchandise parts, automobile parts, electrical and electronic components, and civil engineering and construction materials.

[0047] Examples of general merchandise parts include tableware such as plates, cups, bowls, chopsticks, knives, forks, and spoons; resin screws; watch frames; fasteners; toothbrushes; trays; blisters; tubes; plastic cans; containers; tanks; baskets; cosmetic containers; shampoo bottles; beverage bottles; fruit baskets; egg cartons; clear files; bottle caps; and bottles.

[0048] Automotive parts applications include, for example, engine peripheral parts such as engine covers, air intake manifolds, throttle bodies, air intake pipes, radiator tanks, radiator supports, radiator hoses, radiator grilles, timing belt covers, water pump inlets, water pump outlets, cooling fans, fan shrouds, and engine mounts; mechanical parts such as propeller shafts, stabilizer bar linkage rods, accelerator pedals, pedal modules, seal rings, bearing retainers, gears, driven gears, and electric power steering gears; oil pans, oil filter housings, oil filter caps, oil level gauges, fuel tanks, fuel tubes, fuel cutoff valves, canisters, and fuel derailleurs. Examples include fuel and piping system components such as livery pipes, fuel filler necks, fuel sender modules, and fuel piping fittings; electrical system components such as wire harnesses, relay blocks, sensor housings, enclosures, ignition coils, distributors, thermostat housings, quick connectors, lamp reflectors, lamp housings, lamp extensions, lamp sockets, and horn bobbins; and various interior and exterior parts such as muffler covers, intake ducts, rear spoilers, wheel covers, wheel caps, cowl vent grilles, air outlet louvers, air scoops, hood bulges, fenders, tailgates, shift lever housings, window regulators, door locks, door handles, and outside door mirror stays.

[0049] Applications in electrical and electronic components include connectors, LED reflectors, switches, sensors, sockets, capacitors, jacks, fuse holders, relays, coil bobbins, resistors, ICs, LED housings, and various enclosures. [Examples]

[0050] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. The physical properties were measured by the following method.

[0051] A.Measurement method (1) Polyolefin MFR The measurement was performed using a melt indexer under the conditions of 230°C and 2.16 kg.

[0052] (2) Relative viscosity of polyamides A sample solution with a concentration of 1 g / dL was prepared by dissolving the sample in 96% sulfuric acid. Subsequently, the falling time of the sample solution and solvent was measured at a temperature of 25°C using an Ubbelohde viscometer, and the relative viscosity was determined using the following formula. Relative viscosity = (falling time of sample solution) / (falling time of solvent only)

[0053] (3) Tensile strength, flexural strength Using the obtained final composition (mixture or kneaded product), injection molding was performed using an injection molding machine (Toshiba Machine Co., Ltd. EC-100S model) under the following conditions: resin temperature 260°C, mold temperature 80°C, holding pressure 30 MPa, injection speed 50 mm / s, injection pressure 100 MPa, and cooling time 10 seconds, to obtain ISO multipurpose test specimens. Tensile strength and flexural strength were measured using ISO multipurpose test specimens in accordance with ISO 178. Furthermore, moldability was evaluated by the length of the weighing time during specimen molding.

[0054] (4) Deodorizing performance evaluation The final composition (mixture or kneaded product) obtained was evaluated for odor during injection molding. Specifically, purging (the process of removing resin from the heating cylinder) was performed during injection molding, and the odor of the purged block was examined and evaluated based on the following criteria using a sensory evaluation. ◎: The odor is not noticeable at all (best); ○: There is a slight odor, but it's not noticeable (Excellent); △: The smell is slightly noticeable, but it's not a problem for practical use (acceptable); ×: The odor is clearly noticeable and poses a practical problem (failure); ××: The smell is so bad it's noticeable.

[0055] Furthermore, as a reference value, the odor level around the purge block was measured using a New Cosmos Electric Co., Ltd. odor sensor XP-329IIIR.

[0056] (5) Evaluation of moldability The moldability of the obtained final composition (mixture or kneaded product) was evaluated when it was injection molded using a Shibaura Machine Co., Ltd. EC-100S injection molding machine (feed distance 55 cm). For details, the time it took for the mixture to enter the cylinder of the molding machine from the bottom of the hopper when it was fed from the hopper at 100 rpm (metering time during injection molding) was measured and evaluated based on the following. ◎: 5 seconds or less (best); ○: Over 5 seconds, 7 seconds or less (Excellent); △: More than 7 seconds, 10 seconds or less (Pass); ×: More than 10 seconds (fail).

[0057] (6) Overall evaluation The overall evaluation results show the worse of the two evaluations: the deodorizing performance evaluation and the moldability evaluation.

[0058] B. Raw materials (1) Thermoplastic resin (A) • Polypropylene, manufactured by Prime Polymer Co., Ltd., J-700GP (MFR=8g / 10min) • Polyamide Unitika A1030SR (PA6) (relative viscosity = 2.5)

[0059] (2)Eggshell powder (B) • GT-29 manufactured by Green Techno 21 (average particle size = 15 μm) (unfired)

[0060] (3) Deodorizer (C) • Deodorizer (i) PurgeLite (formerly known as DashLite) ZH (Zeolite with zinc ions supported) manufactured by Sinanen Zeomic Co., Ltd. (Average particle size 1-2 μm, specific surface area 300 m²) 2 / g or more). • Deodorizer (ii) A mixture of amorphous silica powder and zinc oxide powder.

[0061] Example 1 80 parts by mass of polyamide 6 resin (PA6) as thermoplastic resin (A) and 20 parts by mass of Green Techno 21) as eggshell powder (B) were supplied to the main hopper of a twin-screw extruder (manufactured by Japan Steel Works: TEX-44αIII, screw diameter 47 mm) and melted at 260°C. After thorough melting and kneading, the mixture was extruded into strands and cooled and solidified, then cut with a pelletizer to obtain pellets (resin particles) of the resin composition. Subsequently, 0.2 parts by mass of deodorant (i) (per 100 parts by mass of pellets) were added and mixed (dry blended) to obtain the final composition. The pellets had a cylindrical shape. The dimensions of the pellets (resin particles) were an average diameter of 3 mm and a length of 4 mm.

[0062] Examples 2-9 and Comparative Examples 2-5 The final composition was obtained by performing the same procedure as in Example 1, except that the types and amounts of thermoplastic resin (A), eggshell powder (B), and deodorant (C) were changed as shown in Table 1.

[0063] Comparative Example 1 80 parts by mass of polypropylene resin (PP) as thermoplastic resin (A), 20 parts by mass of Green Techno 21 as eggshell powder (B), and 0.2 parts by mass of deodorant (i) were mixed and then supplied to the main hopper of a twin-screw extruder (manufactured by Japan Steel Works: TEX-44αIII, screw diameter 47 mm) and melted at 190°C. After thorough melting and kneading, the mixture was extruded into strands and cooled and solidified, then cut with a pelletizer to obtain pellets of the resin composition.

[0064] Comparative Example 6 The final composition was obtained by mixing (dry blending) 80 parts by mass of polypropylene resin (PP) as thermoplastic resin (A), 20 parts by mass of Green Techno 21 as eggshell powder (B), and 0.2 parts by mass of deodorant (i).

[0065] Table 1 shows the resin compositions of Examples 1-9 and Comparative Examples 2-6, as well as their evaluation results.

[0066] [Table 1]

[0067] The mixtures of Examples 1 to 9 met all the requirements specified in the present invention, and therefore had sufficient suppression of unpleasant odors during molding and excellent moldability.

[0068] In Comparative Example 1, the deodorizer was kneaded together with thermoplastic resin (A) and eggshell powder (B), resulting in a reduced deodorizing effect during molding. The mixture in Comparative Example 2 contained a higher amount of eggshell powder (B) than specified in the present invention. As a result, it had poor operability during melt-kneading, the extruded resin strands lacked continuity, and resin particles could not be produced. Therefore, the overall evaluation result for Comparative Example 2 was "×". The mixture in Comparative Example 3 had an insufficient deodorizing effect because the amount of deodorant was less than that specified in the present invention. The mixture in Comparative Example 4 had a higher deodorizing effect because it contained more deodorizer than the amount specified in the present invention, but its moldability was reduced. Comparative Example 5 used a mixture of amorphous silica powder and zinc oxide powder as a deodorant, resulting in a low deodorizing effect and failure to reduce odor during molding. In Comparative Example 6, the mixture was prepared by mixing the thermoplastic resin (A) and eggshell powder (B) with the deodorant (i) without melt-kneading them together. As a result, the mixture did not enter the cylinder of the molding machine from the bottom of the hopper during molding. [Industrial applicability]

[0069] The thermoplastic resin composition of the present invention is useful for any application in which thermoplastic resin (A) (e.g., polyolefins and polyamides) is used or contained. Such applications include, for example, molded articles such as general merchandise parts, automotive parts, electrical and electronic components, and civil engineering and construction materials.

Claims

1. Resin particles comprising thermoplastic resin (A) and eggshell powder (B); and Deodorizer (C) A thermoplastic resin composition which is a mixture containing, The mass ratio of the thermoplastic resin (A) to the eggshell powder (B) is 98 / 2 to 20 / 80. The deodorant (C) is a metal-supported zeolite, A thermoplastic resin composition in which the amount of the deodorant (C) is 0.05 to 0.80 parts by mass per 100 parts by mass of the total amount of the thermoplastic resin (A) and the eggshell powder (B).

2. The thermoplastic resin composition according to claim 1, wherein the resin particles are resin particles in which the eggshell powder (B) is dispersed in the thermoplastic resin (A).

3. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (A) is a polyolefin, a polyamide, or a mixture thereof.

4. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (A) is polypropylene, polyethylene, or a mixture thereof.

5. The thermoplastic resin composition according to claim 1, wherein the eggshell powder (B) is an uncalcined product.

6. The thermoplastic resin composition according to claim 1, wherein the average particle size of the eggshell powder (B) is 10 to 70 μm.

7. The thermoplastic resin composition according to claim 1, wherein the metal-supported zeolite is a metal aluminosilicate salt.

8. The thermoplastic resin composition according to claim 1, wherein the content of the deodorant (C) is 0.15 to 0.50 parts by mass per 100 parts by mass of the total amount of the thermoplastic resin (A) and the eggshell powder (B).

9. The mass ratio of the thermoplastic resin (A) to the eggshell powder (B) is 97 / 3 to 85 / 15. The thermoplastic resin composition according to claim 8.

10. A resin particle forming step of melting and kneading thermoplastic resin (A) and eggshell powder (B) to obtain resin particles; and Mixing step of mixing the resin particles and deodorant (C) to obtain a mixture A method for producing a thermoplastic resin composition containing the above.

11. The method for producing a thermoplastic resin composition according to claim 10, wherein the mixture is a dry blend.

12. A method for producing a thermoplastic resin composition according to claim 10, comprising producing a thermoplastic resin composition according to any one of claims 1 to 9.

13. A molded article comprising the thermoplastic resin composition according to any one of claims 1 to 9.

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