Thermoplastic resin composition, molded body, method for manufacturing thermoplastic resin composition and method for manufacturing molded body

Abstract

A thermoplastic resin composition containing particles is provided, which improves dispersibility and achieves excellent near-infrared absorption of molded articles, suppresses defects and imperfections during molding, and improves processability. The thermoplastic resin composition comprises a modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and a thermoplastic resin (C). The amount of the modified maleic anhydride-styrene copolymer (A) added relative to 100 parts by mass of the near-infrared absorbing metal oxide particles (B) is 20 to 150 parts by mass, and the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm in size within a 200 μm square field of view observed under a microscope is 50 or less.

Description

[Technical Field]

[0001] This invention relates to thermoplastic resin compositions, molded articles, methods for manufacturing thermoplastic resin compositions and molded articles, and particularly to thermoplastic resin compositions containing near-infrared absorbing metal oxide particles. [Previous Technology]

[0002] Resin products that have the property of absorbing light in the near-infrared region and generating heat include fibers and clothing made from such fibers, or films, etc. To impart this property to these products, it is necessary to coat the near-infrared absorbing material onto the surface of the product or disperse it internally. From a durability perspective, dispersing it internally is preferable, but depending on the dispersion state, the property and processability may be affected.

[0003] Conventional near-infrared absorbing materials include, for example, materials that have high transmittance in the visible light region and low transmittance in the near-infrared region, such as tungsten oxide microparticles and composite tungsten oxide microparticles. Furthermore, fibers incorporating such near-infrared absorbing materials have also been disclosed (Patent Document 1).

[0004] Furthermore, a conventional method for manufacturing thermoplastic resin compositions containing near-infrared absorbing materials has been disclosed, which includes steps of mixing composite particles, a compatibilizer, and polyethylene. The composite particles comprise a dispersant and microparticles such as tungsten oxide coated with the dispersant. The dispersant of the composite particles comprises a resin containing a polar group, and the compatibilizer is a polyolefin containing a polar group (Patent Documents 2, 3). These disclosures indicate that by treating the microparticles with a dispersant containing a resin containing a polar group, and further using a polyolefin containing a polar group as a compatibilizer for mixing, the dispersibility of the composite tungsten oxide microparticles in polyethylene or polypropylene, as well as the film processability, can be improved. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 7226321 [Patent Document 2] Patent No. 7190877 [Patent Document 3] Patent No. 7190878 [Summary of the Invention]

[0006] [Problem to be solved by the invention] However, in Patent Document 1, since the near-infrared absorbing material is simply melt-mixed with thermoplastic resin, the dispersibility of the near-infrared absorbing material cannot be said to be sufficient. Due to secondary agglomeration, the processing stability of filament making or film formation deteriorates. In addition, there is also the problem of increased haze value of the film.

[0007] Furthermore, in Patent Documents 2 and 3, since polyethylene or polypropylene is non-polar, its affinity with dispersants and compatibilizers is low, and the dispersion of microparticles during compounding cannot be considered sufficient. In particular, a high degree of dispersibility is required when using the aforementioned thermoplastic resin composition to melt-mold fibers, but the aforementioned manufacturing methods struggle to achieve the degree of dispersibility necessary to fiberize the thermoplastic resin composition. Moreover, since the aforementioned compatibilizers have low heat resistance, adding polyolefins containing polar groups to high-melting-point thermoplastic resins such as polyethylene terephthalate (PET) or polyamide may lead to deterioration of processability.

[0008] The object of this invention is to provide a thermoplastic resin composition containing particles, a molded article, a method for manufacturing the thermoplastic resin composition containing particles, and a method for manufacturing the molded article. This method can improve dispersibility and achieve excellent near-infrared absorption of the molded article, and can suppress the occurrence of defects and imperfections during molding, while improving processability. [Technical Means for Solving the Problem]

[0009] Through repeated and in-depth research, the inventors have discovered that when a modified maleic anhydride-styrene copolymer is added to a thermoplastic resin composition containing near-infrared absorbing metal oxide particles, (a) since the modified maleic anhydride-styrene copolymer possesses both hydrophilicity derived from maleic anhydride and hydrophobicity derived from styrene, the hydrophilic portion exhibits good affinity with the near-infrared absorbing metal oxide particles, while the hydrophobic portion exhibits good affinity with the thermoplastic resin. Furthermore, (b) by combining other compounds with the modified portions of the modified maleic anhydride as the unit structure, the copolymer forms a comb-like structure, which maintains the interparticle distance between the near-infrared absorbing metal oxide particles in the thermoplastic resin composition. As a result, the dispersibility and stability of the near-infrared absorbing metal oxide in the thermoplastic resin composition are improved. Furthermore, this allows for the suppression of defects such as fiber breakage and defects during the molding of fibers and films, while improving processability. Additionally, excellent optical properties can be achieved in the molded fiber structures and films.

[0010] That is to say, the present invention provides the following composition. [1] A thermoplastic resin composition comprising modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B) and thermoplastic resin (C), wherein in the thermoplastic resin composition, the amount of modified maleic anhydride-styrene copolymer (A) added is 20 to 150 parts by mass relative to 100 parts by mass of the near-infrared absorbing metal oxide particles (B), and the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm in a square field of view observed by a microscope is 50 or less.

[0011] [2] The thermoplastic resin composition as described in [1], wherein the modified maleic anhydride-styrene copolymer (A) has a weight average molecular weight of 1,000 to 20,000.

[0012] [3] The thermoplastic resin composition as described in [1], wherein the near-infrared absorbing metal oxide particles (B) are surface modified by a dispersant (b) having a polar group, and at least a portion of the modified maleic anhydride-styrene copolymer (A) is combined with the near-infrared absorbing metal oxide particles (B) via the dispersant (b).

[0013] [4] The thermoplastic resin composition as described in [1], wherein the near-infrared absorbing metal oxide particles (B) are selected from one or more of the group consisting of cesium tungsten oxide, indium tin oxide and antimony tin oxide.

[0014] [5] The thermoplastic resin composition as described in [1] is characterized in that the thermoplastic resin (C) is selected from one or more of the group consisting of polyester resins, polyamide resins and polyurethane resins.

[0015] [6] A molded body is a melt-molded article of a thermoplastic resin composition as described in [1] or [2].

[0016] [7] A method for manufacturing a thermoplastic resin composition includes the following steps: mixing modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B) and thermoplastic resin (C), and performing melt mixing at a temperature above the melting point of the thermoplastic resin (C), wherein in the method for manufacturing the thermoplastic resin composition, the amount of modified maleic anhydride-styrene copolymer (A) added is 20 to 150 parts by mass relative to 100 parts by mass of the near-infrared absorbing metal oxide particles (B), and the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm in a square field of view observed by a microscope is 50 or less.

[0017] [8] The method for manufacturing a thermoplastic resin composition as described in [7] includes the step of preparing an aqueous dispersion of the near-infrared absorbing metal oxide particles (B), and mixing the modified maleic anhydride-styrene copolymer (A), the aqueous dispersion of the near-infrared absorbing metal oxide particles (B), and the thermoplastic resin (C).

[0018] [9] The method for manufacturing a thermoplastic resin composition as described in [7], wherein the modified maleic anhydride-styrene copolymer (A) has a weight average molecular weight of 1,000 to 20,000.

[0019]

[10] The method for manufacturing a thermoplastic resin composition as described in [7], wherein the pH of the modified maleic anhydride-styrene copolymer (A) is 5 to 9 when it is prepared into a 10% by mass aqueous solution.

[0020]

[11] The method for manufacturing a thermoplastic resin composition as described in [7], wherein the near-infrared absorbing metal oxide particles (B) are surface modified by a dispersant (b) having a polar group, and at least a portion of the modified maleic anhydride-styrene copolymer (A) is combined with the near-infrared absorbing metal oxide particles (B) via the dispersant (b).

[0021]

[12] The method for manufacturing a thermoplastic resin composition as described in [7], wherein the near-infrared absorbing metal oxide particles (B) are selected from one or more of the group consisting of cesium tungsten oxide, indium tin oxide and antimony tin oxide.

[0022]

[13] The method for manufacturing a thermoplastic resin composition as described in [7], wherein the thermoplastic resin (C) is selected from one or more of the group consisting of polyester resins, polyamide resins and polyurethane resins.

[0023]

[14] A method for manufacturing a molded article includes the step of: melt molding a thermoplastic resin composition obtained by the manufacturing method described in [7]. [Effects of the Invention]

[0024] According to the present invention, it is possible to improve dispersibility and achieve excellent near-infrared absorption of the molded article, and to suppress the occurrence of defects or flaws during molding, while improving processability.

Implementation Method

[0026] Hereinafter, an embodiment of the present invention will be described, but the scope of the present invention is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present invention. Furthermore, regarding specific parameters, when multiple upper and lower limits are provided, any combination of these upper and lower limits can be used as an appropriate numerical range.

[0027] <Thermoplastic Resin Composition> The thermoplastic resin composition of this embodiment is a thermoplastic resin composition comprising modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C), wherein the amount of modified maleic anhydride-styrene copolymer (A) added is 20 to 150 parts by mass relative to 100 parts by mass of near-infrared absorbing metal oxide particles (B), and the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm in a square field of view observed under a microscope is 50 or less.

[0028] (Modified maleic anhydride-styrene copolymer (A)) Modified maleic anhydride-styrene copolymer (A) is not particularly limited as long as it is a copolymer of modified maleic anhydride and styrene. As a unit structure, modified maleic anhydride-styrene copolymer (A) may contain one type of modified maleic anhydride or more types of modified maleic anhydride. In addition, thermoplastic resin compositions may contain copolymers of maleic anhydride and styrene (hereinafter also referred to as "unmodified maleic anhydride-styrene copolymer"), provided that they contain modified maleic anhydride-styrene copolymer (A).

[0029] In this embodiment, the amount of modified maleic anhydride-styrene copolymer (A) added is 20 to 150 parts by mass relative to 100 parts by mass of near-infrared absorbing metal oxide particles (B), preferably 25 to 130 parts by mass, and more preferably 30 to 110 parts by mass. By adding 20 to 150 parts by mass of modified maleic anhydride-styrene copolymer (A) relative to 100 parts by mass of near-infrared absorbing metal oxide particles (B), the modified maleic anhydride-styrene copolymer (A) can exist at a high concentration at the interface between the near-infrared absorbing metal oxide particles (B) and the thermoplastic resin (C), thereby improving the affinity between the near-infrared absorbing metal oxide particles (B) and the thermoplastic resin (C) and thus improving dispersibility.

[0030] The weight average molecular weight of the modified maleic anhydride-styrene copolymer (A) is preferably 1,000 to 20,000, more preferably 1,500 to 15,000, and even more preferably 2,000 to 10,000. By having the modified maleic anhydride-styrene copolymer (A) have a weight average molecular weight of 1,000 to 20,000, the dispersibility of near-infrared absorbing metal oxide particles (B) in the thermoplastic resin (C) can be further improved.

[0031] Modified maleic anhydride-styrene copolymer (A) is a product in which the carboxyl group of maleic anhydride-styrene copolymer is modified by a modifier. There are no special restrictions. It can be a product in which part of the carboxyl group of maleic anhydride-styrene copolymer is modified by a modifier, or it can be a product in which all of the carboxyl groups are modified.

[0032] There are no particular limitations on the modifier; for example, compounds having hydroxyl, amino, epoxy, etc., can be listed. In addition, one compound can be used as a modifier, or two or more compounds can be used as modifiers.

[0033] Specific examples of modified maleic anhydride-styrene copolymers (A) include DISPERBYK-2010, DISPERBYK-2012, DISPERBYK-2013, DISPERBYK-2015, DISPERBYK-190, BYKJET-1951, and BYKJET-9152 manufactured by BAK Chemical Japan Co., Ltd. Among these, DISPERBYK-2012, DISPERBYK-2013, DISPERBYK-2015, and DISPERBYK-190, which have high water solubility at room temperature, are preferred.

[0034] (Near-infrared absorbing metal oxide particles (B)) The near-infrared absorbing metal oxide particles (B) are not particularly limited to any oxide particles that absorb light of near-infrared wavelengths. Preferably, the near-infrared absorbing metal oxide particles (B) are surface-modified by a dispersant (b) with polar groups, and at least a portion of the modified maleic anhydride-styrene copolymer (A) is combined with the near-infrared absorbing metal oxide particles (B) via the dispersant (b). The dispersant (b) with polar groups is added to the particles during the manufacture of the near-infrared absorbing metal oxide particles (B) from a dispersibility perspective. On the other hand, the low affinity of the dispersant (b) with polar groups for the thermoplastic resin (C) may cause secondary agglomeration of the thermoplastic resin composition during melt molding. In this embodiment, when the near-infrared absorbing metal oxide particles (B) are surface modified by a dispersant (b) having polar groups, the affinity with the thermoplastic resin (C) can be improved by the combination of the dispersant (b) with at least a portion of the modified maleic anhydride-styrene copolymer (A), thereby inhibiting the secondary aggregation of the near-infrared absorbing metal oxide particles (B) and improving dispersibility.

[0035] Dispersants (b) having polar groups include, for example, compounds having one or more selected from amino, hydroxyl, carboxyl, and epoxy groups. Specific examples of dispersants (b) include SOLSPERSE3000, SOLSPERSE9000, SOLSPERSE11200, SOLSPERSE56000 manufactured by Lubricants Japan Co., Ltd.; DISPERBYK-101, DISPERBYK-164, DISPERBYK-181, DISPERBYK-184 manufactured by BAK Chemical Japan Co., Ltd.; Alphon UC-3000, Alphon UF-5022, Alphon UG-4010, Alphon UG-4070 manufactured by Toa Synthetic Co., Ltd.; and Ajispa PB-711, Ajispa PB-821, Ajispa PB-822 manufactured by Ajinomoto Fine Technology Co., Ltd.

[0036] Specific examples of near-infrared absorbing metal oxide particles (B) include one or more selected from the group consisting of cesium tungsten oxide (CWO), indium tin oxide (ITO), and antimony tin oxide (ATO). Among these, cesium tungsten oxide is preferred from the viewpoint of near-infrared absorption performance.

[0037] In this embodiment, within a 200 μm square field of view observed under a microscope, the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm is 50 or less, preferably 30 or less, and more preferably 10 or less. By ensuring that the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm within the aforementioned field of view is 50 or less, processability such as wire drawing, transparency of molded articles, and near-infrared absorption can be improved. Furthermore, the content of near-infrared absorbing metal oxide particles (B) may be limited depending on the specifications of the thermoplastic resin composition, but even with a low content of near-infrared absorbing metal oxide particles (B), high near-infrared absorption can still be achieved.

[0038] The primary average particle size of the near-infrared absorbing metal oxide particles (B) is not particularly limited, but 10 nm to 200 nm is preferred, 20 nm to 150 nm is more preferred, and 30 nm to 120 nm is even more preferred. By using a primary average particle size of 30 nm to 120 nm for the near-infrared absorbing metal oxide particles (B), a good balance between near-infrared absorption and dispersibility can be achieved.

[0039] (Thermoplastic resin (C)) Thermoplastic resin (C) is not particularly limited to any resin that is thermoplastic. Specific examples of thermoplastic resin (C) may be selected from one or more of the group consisting of polyester resins, polyamide resins, and polyurethane resins.

[0040] Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexanedimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, and polylactic acid. Furthermore, these polyesters can also be copolymers copolymerized with alcohols such as butanediol or dicarboxylic acids such as isophthalic acid as a third component, or mixtures of these various polyesters.

[0041] Examples of polyamide resins include aliphatic polyamides and their copolymers such as polyamide 6, polyamide 66, polyamide 610, polyamide 10, polyamide 1010, polyamide 11, polyamide 12, and polyamide 6-12, as well as semi-aromatic polyamides synthesized from aromatic dicarboxylic acids and aliphatic diamines.

[0042] Examples of polyurethane resins include ether-based polyurethane resins and ester-based polyurethane resins. Ether-based polyurethane resins can be selected arbitrarily as long as they contain ether bonds within the molecule; resins obtained from polymeric diols and organic diisocyanates containing ether bonds can be used as raw materials. Ester-based polyurethane resins can be selected arbitrarily as long as they contain ester bonds within the molecule; resins obtained from polymeric diols and organic diisocyanates containing ester bonds can be used as raw materials.

[0043] As a method for determining the resin decomposition of the thermoplastic resin composition of this embodiment, for example, intrinsic viscosity (IV), melt flow rate (MFR), and melt volume rate (MVR) can be listed. Among them, polyester resin is expressed as intrinsic viscosity (IV). According to the JIS K7390 standard, the IV (intrinsic viscosity) retention rate measured by the following formula (1) is preferably 70% or more, and more preferably 80% or more. When the IV retention rate is 70% or more, it can prevent adverse conditions such as molding difficulties and degradation of the physical properties of the molded product. IV retention rate (%) = IV measured value of thermoplastic resin composition / IV of polyethylene terephthalate × 100% ・・・ Formula (1)

[0044] <Molded Article> The molded article of this embodiment is a melt-molded article of the above-mentioned thermoplastic resin composition. The molded article is not particularly limited, and examples include fibers, films, and fibrous structures.

[0045] (Fiber) The fiber of this embodiment can be obtained, for example, by melt spinning the above-described thermoplastic resin composition. The fiber can also be obtained by mixing a masterbatch composed of the above-described thermoplastic resin composition with other thermoplastic resins to obtain a thermoplastic resin composition, and then melt spinning it.

[0046] The fiber contains modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C). The types and amounts of each component constituting the fiber can be the same as the types and amounts of each component constituting the above-mentioned thermoplastic resin composition. Furthermore, provided that the fiber contains modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C), it may also contain one or more other components.

[0047] (Film) The film of this embodiment is obtained by thinning the above-mentioned thermoplastic resin composition. The film may also be obtained by mixing a masterbatch composed of the above-mentioned thermoplastic resin composition with other thermoplastic resins to obtain a thermoplastic resin composition, and then thinning it.

[0048] The film contains modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C). The types and amounts of each component constituting the film can be the same as those constituting the thermoplastic resin composition described above. Furthermore, provided that the film contains modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C), it may also contain one or more other components.

[0049] (Fiber Structure) The fiber structure of this embodiment is composed of part or all of the aforementioned fibers. Examples of fiber structures include cloth, felt, sheet material, etc.

[0050] <Method for Manufacturing Thermoplastic Resin Composition> The method for manufacturing a thermoplastic resin composition according to this embodiment includes the following steps: mixing modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C), and performing melt mixing at a temperature above the melting point of the thermoplastic resin (C). In the method for manufacturing the thermoplastic resin composition, the amount of modified maleic anhydride-styrene copolymer (A) added is 20 to 150 parts by mass relative to 100 parts by mass of near-infrared absorbing metal oxide particles (B), and the number of near-infrared absorbing metal oxide particles (B) larger than 2 μm in a square field of view observed under a microscope is 50 or less.

[0051] In the above steps, the mixture of modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C) is melt-blended at a temperature above the melting point of thermoplastic resin (C). By melt-blending the above mixture at a temperature above the melting point of thermoplastic resin (C), the dispersibility of near-infrared absorbing metal oxide particles (B) in the thermoplastic resin composition can be improved. When the thermoplastic resin (C) is composed of multiple thermoplastic resins, it is preferable to select the one with the highest melting point from the multiple thermoplastic resins and melt-blend at a temperature above that melting point.

[0052] The method of melting and mixing the above mixture is not particularly limited as long as the melting and mixing can be carried out while adjusting the temperature. Known devices such as twin-screw extruders can be used.

[0053] The modified maleic anhydride-styrene copolymer (A) used in the above steps preferably has a weight average molecular weight of 1,000 to 20,000, more preferably 1,500 to 15,000, and even more preferably 2,000 to 10,000. By using a modified maleic anhydride-styrene copolymer (A) with a weight average molecular weight of 1,000 to 20,000, the gas generated by volatilization during processing can be suppressed, the residual amount of modified maleic anhydride-styrene copolymer (A) in the thermoplastic resin composition can be increased, thereby improving heat resistance. At the same time, the increase in viscosity can also be suppressed, thereby improving production efficiency.

[0054] There are no particular limitations on the modified maleic anhydride-styrene copolymer (A). Its unit structure may have one amine-modified maleic anhydride or two or more amine-modified maleic anhydrides. When the unit structure of the modified maleic anhydride-styrene copolymer (A) has two amine-modified maleic anhydrides, for example, the case of grafting with two amines to form a maleimide backbone can be cited. As a specific example of the modified maleic anhydride-styrene copolymer (A), the same structure as described above can be used.

[0055] In the above step, the modified maleic anhydride-styrene copolymer (A) can be fed into a melt mixer together with near-infrared absorbing metal oxide particles (B) and thermoplastic resin (C), or it can be fed into the melt mixer together with thermoplastic resin (C) after being mixed with near-infrared absorbing metal oxide particles (B). From the viewpoint of improving dispersibility, it is preferable to feed it into the melt mixer together with thermoplastic resin (C) after mixing with near-infrared absorbing metal oxide particles (B). Furthermore, the pH value of the modified maleic anhydride-styrene copolymer (A) when prepared into a 10% by mass aqueous solution is preferably 5 to 9, and more preferably 5.5 to 8.5. By preparing the modified maleic anhydride-styrene copolymer (A) into a 10% by mass aqueous solution with a pH value of 5 to 9, the hydrolysis of thermoplastic resin during processing can be suppressed.

[0056] As a specific example of the near-infrared absorbing metal oxide particle (B) used in the above step, one or more selected from the group consisting of cesium tungsten oxide (CWO), indium tin oxide (ITO), and antimony tin oxide (ATO) can be listed. Among them, cesium tungsten oxide is preferred from the viewpoint of near-infrared absorption performance.

[0057] In the above step, the near-infrared absorbing metal oxide particles (B) can be mixed as a powder or as an aqueous dispersion. When the near-infrared absorbing metal oxide particles (B) are mixed as a powder, the presence of the modified maleic anhydride-styrene copolymer (A) can sufficiently improve the dispersibility. Furthermore, when the near-infrared absorbing metal oxide particles (B) are mixed as an aqueous dispersion, an aqueous dispersion of the near-infrared absorbing metal oxide particles (B) is prepared, and the modified maleic anhydride-styrene copolymer (A), the aforementioned aqueous dispersion of the near-infrared absorbing metal oxide particles (B), and the thermoplastic resin (C) are mixed. This further promotes dispersibility. In the aforementioned aqueous dispersion, the content of the near-infrared absorbing metal oxide particles (B) is preferably 10% to 60% by mass, and more preferably 20% to 40% by mass.

[0058] The near-infrared absorbing metal oxide particles (B) are surface-modified by a dispersant (b) having polar groups. In the aforementioned steps, a modified maleic anhydride-styrene copolymer (A) may also be used for treatment. That is, at least a portion of the modified maleic anhydride-styrene copolymer (A) may be combined with the near-infrared absorbing metal oxide particles (B) via the dispersant (b). As a specific example of a dispersant (b) having polar groups, the same composition as described above may be used.

[0059] The thermoplastic resin (C) may be one or more selected from the group consisting of polyester resins, polyamide resins, and polyurethane resins. Preferably, the melt mixing is performed at a temperature above the melting point of the thermoplastic resin (C). When the thermoplastic resin (C) is selected from multiple groups consisting of polyester resins, polyamide resins, and polyurethane resins, the melt mixing temperature is preferably selected from the thermoplastic resins with the highest melting point, and the melt mixing is performed at a temperature above that melting point, more preferably within a temperature range of melting point +20°C to melting point +50°C.

[0060] <Method for Manufacturing a Molded Body> The method for manufacturing a molded body according to this embodiment includes a step of melt molding a thermoplastic resin composition obtained by the above-described manufacturing method. In the case of melt molding a fiber as a molded body, the thermoplastic resin composition obtained by the above-described manufacturing method can be melt-spun. In melt spinning, a commonly used melt spinning apparatus can be used. Alternatively, the fiber can be obtained by mixing a masterbatch composed of the above-described thermoplastic resin composition with other thermoplastic resins to obtain a thermoplastic resin composition, and then melt-spinning it. In the case of melt molding a film as a molded body, it is obtained by thinning the thermoplastic resin composition obtained by the above-described manufacturing method. The film molding method is not particularly limited, but examples include hot pressing, single-layer or multi-layer blown film methods, and T-die methods. Alternatively, the film can be obtained by mixing a masterbatch composed of the above-described thermoplastic resin composition with other thermoplastic resins to obtain a thermoplastic resin composition, and then thinning it to form a film.

[0061] By employing the above-described method for manufacturing a thermoplastic resin composition and a molded article, the thermoplastic resin composition and molded article of this embodiment can be manufactured. [Example]

[0062] The present invention will be further described in detail below through embodiments. The present invention is not limited to the following embodiments.

[0063] Experiment A: Preparation and evaluation of near-infrared absorbing thermoplastic resin film (Example 1) 49.33 parts by mass of thermoplastic resin polyamide 11 (manufactured by Arkema, Rilsan (registered trademark) BMNO), 2.5 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd.: YMW-D20, Cs 0.33WO 320% by mass), and 0.17 parts by mass of dispersant DISPERBYK-2013 (manufactured by BAK Chemicals Japan Co., Ltd., modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were mixed in a laboratory mixer to obtain the thermoplastic resin composition of Example 1. The thermoplastic resin composition was hot-pressed into a film to obtain a near-infrared absorbing thermoplastic resin film 1 containing 1.0 wt% CWO (also known as CsWO) and with a thickness of 110 μm.

[0064] (Example 2) 47.66 parts by weight of the thermoplastic resin polyamide 11 (manufactured by Arkema, Rilsan (registered trademark) BMNO), 2.17 parts by weight of dispersant-treated cesium tungsten oxide powder (manufactured by Sumitomo Metal Mining Co., Ltd.: YMDS-874, Cs 0.33 WO 323 wt%), and 0.17 parts by weight of dispersant DISPERBYK-2013 (manufactured by Bick Chemicals Japan Co., Ltd., modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were mixed in a laboratory mixer to obtain the thermoplastic resin composition of Example 2. This thermoplastic resin composition was hot-pressed into a film to obtain a near-infrared absorbing thermoplastic resin film 2 containing 1.0 wt% CWO and with a thickness of 110 μm.

[0065] (Comparative Example 1) 47.83 parts by weight of the thermoplastic resin polyamide 11 (manufactured by Arkema, Rilsan (registered trademark) BMNO) and 2.17 parts by weight of dispersant-treated cesium tungsten oxide powder (manufactured by Sumitomo Metal Mining Co., Ltd.: YMDS-874, Cs 0.33 WO 323 wt%) were mixed in a laboratory mixer to obtain the thermoplastic resin composition of Comparative Example 1. This thermoplastic resin composition was hot-pressed into a film to obtain a near-infrared absorbing thermoplastic resin film 3 containing 1.0 wt% CWO and with a thickness of 110 μm.

[0066] (Comparative Example 2) 47.41 parts by mass of the thermoplastic resin polyamide 11 (manufactured by Arkema, Rilsan (registered trademark) BMNO), 2.5 parts by mass of a dispersant-treated cesium tungsten oxide aqueous dispersion (manufactured by Sumitomo Metal Mining Co., Ltd.: YMW-D20, Cs 0.33 WO 320 wt%), and 0.09 parts by mass of the dispersant DISPERBYK-2013 (manufactured by Bick Chemicals Japan Co., Ltd., modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were mixed in a laboratory mixer to obtain the thermoplastic resin composition of Comparative Example 2. This thermoplastic resin composition was hot-pressed into a film to obtain a near-infrared absorbing thermoplastic resin film 4 containing 1.0 wt% CWO and with a thickness of 110 μm.

[0067] (Reference Example 1) 50 parts by mass of thermoplastic resin polyamide 11 (manufactured by Arkema, Rilsan (registered trademark) BMNO) were mixed in a laboratory mixer to obtain the thermoplastic resin composition of Reference Example 1. This thermoplastic resin composition was then hot-pressed into a film to obtain a thermoplastic resin film 5 with a thickness of 110 μm.

[0068] <Evaluation> [Dispersion State] The thermoplastic resin composition obtained in the Examples and Comparative Examples was used to prepare a film with a thickness of less than 100 μm by sandwiching it between two glass slides with a heating plate. The number of near-infrared absorbing metal oxide particles exceeding a specific particle size in the film was counted in transmission mode using an optical microscope (Nikon Solutions, ECLIPSE LV100). At 200x magnification, within a square 200 μm field of view, a number of particles larger than 2 μm of 10 or less was considered very good "◎", more than 10 but less than 50 was considered good "〇", and more than 50 was considered poor "×". [Evaluation Criteria] Number of particles larger than 2 μm less than 10... Very good "◎" Number of particles larger than 2 μm more than 10 but less than 50... Good "〇" Number of particles larger than 2 μm more than 50... Poor "×"

[0069] [Haze Measurement (1)] The haze of the films obtained in the Examples and Comparative Examples was measured using a haze meter (Nippon Denshoku Kogyo Co., Ltd., NDH70002II type) according to JIS K7361 standard. A haze difference of less than 1.0% compared to the thermoplastic resin without added near-infrared absorbing metal oxide particles (haze value 2.35%) was considered "Very Good" "◎", a difference of 1.0% or more but less than 5.0% was considered "Good" "〇", and a difference exceeding 5.0% was considered "Poor" "×". [Evaluation Criteria] Haze difference less than 1.0%・・・Very Good "◎" Haze difference 1.0% or more but less than 5.0%・・・Good "〇" Haze difference exceeding 5.0%・・・Poor "×"

[0070] The evaluation results of the above embodiments and comparative examples are shown in Table 1.

[0071] [Table 1]

[0072] As can be seen from the results in Table 1 above, in Examples 1 and 2, the amount of modified maleic anhydride-styrene copolymer (A) added was in the range of 20 to 150 parts by mass relative to 100 parts by mass of near-infrared absorbing metal oxide particles (B), and the number of CWO particles larger than 2 μm was less than 50. Therefore, the dispersibility of CWO particles in the thermoplastic resin composition was excellent, and the obtained near-infrared absorbing thermoplastic resin film had a small haze difference and excellent transparency. Furthermore, in Example 1, the thermoplastic resin composition was prepared using an aqueous dispersion of near-infrared absorbing metal oxide particles (B). Compared with Example 2, which used powder of near-infrared absorbing metal oxide particles (B), the dispersibility of near-infrared absorbing metal oxide particles (B) in the thermoplastic resin composition was excellent, and the obtained near-infrared absorbing thermoplastic resin film had a small haze difference and excellent transparency.

[0073] On the other hand, in Comparative Example 1, the thermoplastic resin composition did not contain modified maleic anhydride-styrene copolymer (A), and the dispersion of near-infrared absorbing metal oxide particles (B) was poor. Furthermore, the obtained near-infrared absorbing thermoplastic resin film had a large haze difference and poor transparency. In Comparative Example 2, the amount of modified maleic anhydride-styrene copolymer (A) added was less than 20 parts by mass relative to 100 parts by mass of near-infrared absorbing metal oxide particles (B). Although the obtained near-infrared absorbing thermoplastic resin film had a smaller haze difference, the dispersion of near-infrared absorbing metal oxide particles (B) was poor.

[0074] <<Experiment B: Evaluation of Fibers and Knitted Fabrics>> (Example 3) <Preparation of CWO Masterbatch> 90 parts by mass of thermoplastic resin polyethylene terephthalate (Mitsui Chemicals, J125S, IV value 0.76), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (Sumitomo Metal Mining, YMW-D20, Cs 0.33WO 320% by mass), and 5 parts by mass of dispersant DISPERBYK-2013 (Bic Chemicals Japan, modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 280°C, 20 μm particle diameter mesh filter). The obtained thermoplastic resin composition was granulated to obtain masterbatch (1).

[0075] <Spinning> Using a multifilament melt spinning apparatus, 210 parts by mass of masterbatch (1) (equivalent to 10.5 parts by mass of CWO) and 840 parts by mass of polyethylene terephthalate (Mitsui Chemicals, J125S) were used as spinning raw materials. Spinning was carried out for 1 hour at a spinning temperature of 280°C, an extrusion rate of 1 kg / h and a take-up speed of 1000 m / min, thereby obtaining infrared absorbing multifilament fibers containing 1.0% by weight of CWO.

[0076] <Production of Woven Fabric> Using the above-mentioned infrared absorption multifilament fibers, a woven fabric with a 30-gauge pitch and a unit area weight of 150g / m2 is produced by a cylindrical knitting machine.

[0077] (Example 4) <Preparation of CWO Masterbatch> 90 parts by mass of thermoplastic resin polyethylene terephthalate (Mitsui Chemicals, J125S, IV value 0.76), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (Sumitomo Metal Mining, YMW-D20, Cs 0.33WO 320% by mass), and 10 parts by mass of dispersant DISPERBYK-2012 (Bic Chemicals Japan, modified maleic anhydride-styrene copolymer, weight average molecular weight 3100, pH=5.62, non-volatile matter 40%) were melt-blended in an 18mm φ twin-shaft extruder (set temperature 250°C, 20μm particle diameter mesh filter). The obtained thermoplastic resin composition was granulated to obtain masterbatch (2).

[0078] <Production of spinning and weaving> Infrared absorbing polyfilament fibers and weaving fabric containing 1.0% by weight of CWO were manufactured by the same method as in Example 1.

[0079] (Example 5) <Preparation of CWO Masterbatch> 91.7 parts by mass of thermoplastic resin polyamide 6 (manufactured by Ube Industries, Ltd., 1015B), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd.: YMW-D20, Cs 0.33WO 320% by mass), and 3.3 parts by mass of dispersant DISPERBYK-2013 (manufactured by BAK Chemicals Japan Co., Ltd., modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 250°C, with a mesh filter capturing particles of 20 μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (3). <Production of spinning and weaving fabric> Infrared absorbing polyfilament fibers and woven fabric containing 1.0% by weight of CWO were manufactured by the same method as in Example 1.

[0080] (Example 6) <Preparation of CWO Masterbatch> 90 parts by mass of thermoplastic resin polylactic acid (manufactured by Unichika Corporation, TE-2000C), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Corporation, YMW-D20, Cs 0.33WO 320% by mass), and 5 parts by mass of dispersant DISPERBYK-2013 (manufactured by BAK Chemicals Japan Co., Ltd., modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were melt-blended in an 18mm φ twin-shaft extruder (set temperature 200°C, with a mesh filter capturing particles of 20μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (4).

[0081] <Production of spinning and weaving> Infrared absorbing polyfilament fibers and weaving fabric containing 1.0% by weight of CWO were manufactured by the same method as in Example 1.

[0082] (Example 7) <Preparation of CWO Masterbatch> 91.7 parts by mass of thermoplastic resin polyamide 11 (manufactured by Arkema, Rilsan (registered trademark), BMNO), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd., YMW-D20, Cs 0.33WO 320% by mass), and 3.3 parts by mass of dispersant DISPERBYK-2013 (manufactured by BAK Chemicals Japan Co., Ltd., modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were melt-blended in an 18mm φ twin-shaft extruder (set temperature 230°C, with a mesh filter capturing particles of 20μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (5).

[0083] <Production of spinning and weaving> Infrared absorbing polyfilament fibers and weaving fabric containing 1.0% by weight of CWO were manufactured by the same method as in Example 1.

[0084] (Example 8) <Preparation of CWO Masterbatch> 91.7 parts by mass of thermoplastic resin polyamide 6 (manufactured by Ube Industries, Ltd., 1015B), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd., YMW-D20, Cs 0.33WO 320% by mass), and 8.3 parts by mass of dispersant DISPERBYK-190 (manufactured by BAK Chemicals Japan Co., Ltd., modified maleic anhydride-styrene copolymer, weight average molecular weight 3900, pH 5.58, non-volatile matter 40%) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 250°C, with a mesh filter capturing particles of 20 μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (6). <Production of spinning and weaving fabric> Infrared absorbing polyfilament fibers and woven fabric containing 1.0% by weight of CWO were manufactured by the same method as in Example 1.

[0085] (Example 9) <Preparation of ATO Masterbatch> 80 parts by mass of thermoplastic resin polyamide 11 (manufactured by Arkema, Rilsan (registered trademark) BMNO), 16.7 parts by mass of antimony tin oxide aqueous dispersion treated with dispersant (manufactured by Special Chemicals, 9387SN, ATO 30% by mass), and 3.3 parts by mass of dispersant DISPERBYK-2013 (manufactured by Bick Chemicals Japan, modified maleic anhydride-styrene copolymer, weight average molecular weight 5200, pH 6.05, non-volatile matter 100%) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 280°C, 20 μm particle diameter mesh filter). The obtained thermoplastic resin composition was granulated to obtain masterbatch (7).

[0086] <Production of spinning and weaving> Infrared absorbing polyfilament fibers and weaving fabric containing 1.0% by weight of ATO were manufactured by the same method as in Example 1.

[0087] (Comparative Example 3) <Preparation of CWO Masterbatch> 95 parts by mass of thermoplastic resin polyethylene terephthalate (PET) (manufactured by Mitsui Chemicals, J125S, IV value 0.76) and 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining, YMW-D20, Cs 0.33WO 320% by mass) were melt-blended in an 18mm φ twin-shaft extruder (set temperature 280°C, supplemented with a mesh filter with a particle diameter of 20μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (8). The dispersion state of the obtained masterbatch (8) was evaluated, and the result was poor "×", therefore, the spinning and weaving properties were not evaluated.

[0088] Comparative Example 4 <Preparation of CWO Masterbatch> 91.7 parts by mass of thermoplastic resin polyethylene terephthalate (PET) (manufactured by Mitsui Chemicals, J125S, IV value 0.76), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining, YMW-D20, Cs 0.33WO 320% by mass), and 3.3 parts by mass of dispersant DISPERBYK-102 (manufactured by BAK Chemicals Japan, phosphate ester, weight average molecular weight 2200, pH 1.53, non-volatile matter 100%) were melt-blended in an 18 mm φ twin-screw extruder (set temperature 280°C, 20 μm particle diameter mesh filter). The obtained thermoplastic resin composition was granulated to obtain masterbatch (9).

[0089] <Spinning and Fabric Production and Evaluation of Spectroscopic Properties> Infrared absorbing polyfilament fibers and woven fabric containing 1.0% by weight of CWO were manufactured by the same method as in Example 1.

[0090] Comparative Example 5 <Preparation of CWO Masterbatch> 90 parts by mass of thermoplastic resin polyethylene terephthalate (PET) (manufactured by Mitsui Chemicals, J125S, IV value 0.76), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining, YMW-D20, Cs 0.33WO 320% by mass), and 5 parts by mass of dispersant SY Gulista CRS-75 (manufactured by Sakamoto Pharmaceutical Co., Ltd., polyglycerol fatty acid ester, weight average molecular weight 5900, pH 9.28, non-volatile matter 100%) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 280°C, 20 μm particle diameter mesh filter). The obtained thermoplastic resin composition was granulated to obtain masterbatch (10). The obtained masterbatch (10) was evaluated for dispersion state and the result was poor "×". Therefore, no spinnability evaluation and woven fabric evaluation were performed.

[0091] Comparative Example 6 <Preparation of CWO Masterbatch> 91.7 parts by mass of thermoplastic resin polyamide 6 (manufactured by Ube Industries, Inc., 1015B), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd.: YMW-D20, Cs 0.33WO 320% by mass), and 3.3 parts by mass of dispersant DISPERBYK-185 (manufactured by BAK Chemicals Japan Co., Ltd., modified polyurethane, pH 8.58, non-volatile matter exceeding 90%) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 280°C, supplemented with a mesh filter with a particle diameter of 20 μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (11). The dispersion state of the obtained masterbatch (11) was evaluated, and the result was "×", therefore, no evaluation of spinnability and woven fabric was performed.

[0092] Comparative Example 7 <Preparation of CWO Masterbatch> 91.7 parts by mass of thermoplastic resin polyamide 6 (manufactured by Ube Industries, Ltd., 1015B), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd.: YMW-D20, Cs 0.33WO 320% by mass), and 3.3 parts by mass of dispersant DISPERBYK-2055 (manufactured by BAK Chemicals Japan Co., Ltd., modified acrylate, pH=9.95, 100% non-volatile matter) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 280°C, with a mesh filter capturing particles of 20 μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (12). The dispersion state of the obtained masterbatch (12) was evaluated, and the result was poor "×", therefore, no evaluation of spinnability and woven fabric was performed.

[0093] Comparative Example 8 <Preparation of CWO Masterbatch> 91.7 parts by mass of thermoplastic resin polyamide 6 (manufactured by Ube Industries, Inc., 1015B), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd.: YMW-D20, Cs 0.33WO 320% by mass), and 3.3 parts by mass of dispersant Adema (registered trademark) QE-800 (manufactured by Mitsui Chemicals Co., Ltd., maleic anhydride modified polyolefin, 100% non-volatile matter) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 250°C, 20 μm particle diameter mesh filter). The obtained thermoplastic resin composition was granulated to obtain masterbatch (13). The dispersion state of the obtained masterbatch (13) was evaluated, and the result was poor "×", therefore, no evaluation of spinnability and woven fabric was performed.

[0094] Comparative Example 9 <Preparation of CWO Masterbatch> 56 parts by mass of thermoplastic resin polyamide 6 (manufactured by Ube Industries, Inc., 1015B), 25 parts by mass of cesium tungsten oxide aqueous dispersion treated with dispersant (manufactured by Sumitomo Metal Mining Co., Ltd.: YMW-D20, Cs 0.33WO 320% by mass), and 39 parts by mass of dispersant Adema (registered trademark) QE-800 (manufactured by Mitsui Chemicals Co., Ltd., maleic anhydride modified polyolefin, 100% non-volatile matter) were melt-blended in an 18 mm φ twin-shaft extruder (set temperature 250°C, mesh filter with particle diameter of 20 μm). The obtained thermoplastic resin composition was granulated to obtain masterbatch (14). The dispersion state of the obtained masterbatch (14) was evaluated, and the result was poor "×", therefore, no spinning performance evaluation and woven fabric evaluation were performed.

[0095] Reference Example 2 <Spinning> Using a multifilament melt spinning apparatus, thermoplastic resin polyethylene terephthalate (manufactured by Mitsui Chemicals, J125S, IV value 0.76) was used as the spinning raw material. Spinning was carried out for 1 hour at a spinning temperature of 280°C, an extrusion rate of 1 kg / h, and a take-up speed of 1000 m / min, thereby obtaining a multifilament fiber of 150 denier and 24 filaments.

[0096] <Fabric Production> Using the above-mentioned multifilament fibers, a woven fabric with a gauge of 30 stitches and a unit area weight of 110g / m2 is produced by a cylindrical knitting machine.

[0097] <Evaluation> [Dispersion State] The thermoplastic resin composition obtained in the Examples and Comparative Examples was used to prepare a film with a thickness of less than 100 μm by sandwiching it between two glass slides using a hot plate. The number of near-infrared absorbing metal oxide particles exceeding a specific particle size in the film was counted in transmission mode using an optical microscope (Nikon Solutions, ECLIPSE LV100). At 200x magnification, within a square 200 μm field of view, a number of particles larger than 2 μm of less than 10 was considered very good "◎", more than 10 but less than 50 was considered good "〇", and more than 50 was considered poor "×". [Evaluation Criteria] Number of particles larger than 2 μm less than 10...very good "◎" Number of particles larger than 2 μm more than 10 but less than 50...good "〇" Number of particles larger than 2 μm more than 50...poor "×"

[0098] [Haze Measurement (2)] A 10% by mass aqueous solution of the modified maleic anhydride-styrene copolymer (A) used in the Examples and Comparative Examples was prepared, and the haze of the aqueous solution was measured using a haze meter (Nippon Denshoku Kogyo Co., Ltd., NDH70002II type) according to JIS K7361 standard. In addition, the solubility of each dispersant in water was visually confirmed. The results are shown in Table 2.

[0099] Table 2

[0100] <Spinning properties> A composite material containing 1 mass% oxide particles is obtained by mixing the masterbatch obtained from the embodiment, the comparative example and the natural resin without the addition of oxide particles at a specified ratio. The resulting composites were melt-spinned, followed by extension to obtain fibers. In case of poor dispersion, it is captured by the nozzle mesh, resulting in a rise in monitoring pressure and thread breakage. No thread breaks within 1 hour and the monitored pressure rise rate was less than 5% was rated as very good “◎”, and no thread breaks within 1 hour and the monitored pressure rise rate exceeded 5% but less than 15% was rated as good “〇”, with broken threads, or no thread breaks but monitored pressure rise above 15% was rated as bad “×”. [Assessment Criteria] No broken threads, and monitored pressure rise rate of less than 5%... Very good "◎" No broken threads, and monitored pressure rise rate of more than 5%, less than 15%... Good "〇" With broken threads, or no broken threads but monitored pressure rise rate of more than 15%... Undesirable "×"

[0101] <IV value determination> The IV value (inherent viscosity) of each sample was measured in accordance with the JIS K7390 standard for the masterbatch containing the thermoplastic resin polyethylene terephthalate (PET) in the embodiments and comparison examples. If the IV value is too low, it can cause problems such as difficulty in molding and decreased physical properties of the molded product. IV retention rates above 80% were rated as very good “◎”, IV retention rates above 70% and less than 80% were rated as good “〇”, and IV retention rates less than 70% were rated as undesirable “×”. The retention rate is calculated according to equation (1). IV retention rate (%) = IV value determination value of each sample / IV value of polyethylene terephthalate × 100%... Formula (1) [Evaluation Criteria] IV retention rate 80% or more... very good "◎" IV retention rate 70% or more and less than 80%... good "〇" IV retention rate less than 70%... bad "×"

[0102] <Near Infrared Transmittance Determination> Use a UV-visible near-infrared spectrophotometer (made by Japan Spectrophotometer, V-770 type) to determine the transmittance of light of light in the near-infrared region with a wavelength of 1000nm to 2000nm in the knitted fabric obtained in the embodiment and comparison example, and find its average value.

[0103] The evaluation results of the above embodiments, comparative examples, are shown in Table 3 .

[0104] [Table 3]

[0105] As can be seen from the results in Table 2 above, in Examples 3 to 9, the amount of modified maleic anhydride-styrene copolymer (A) added was in the range of 20 to 150 parts by mass relative to 100 parts by mass of near-infrared absorbing metal oxide particles (B). Furthermore, within a 200 μm square field of view observed using an electron microscope, the number of near-infrared absorbing metal oxide particles (B) larger than 2 μm was less than 50. Therefore, the near-infrared absorbing metal oxide particles (B) in the thermoplastic resin composition exhibited excellent dispersibility and excellent spinnability. In addition, in Examples 3 to 8, where CWO particles were used as near-infrared absorbing metal oxide particles (B), the near-infrared transmittance was 12.4% to 28.5%, indicating that the knitted fabric had excellent near-infrared absorption.

[0106] Figure 1 shows an optical microscope image of the dispersion state of the thermoplastic resin composition obtained in Example 3. As shown in Figure 1, in the thermoplastic resin composition obtained in Example 3, only a few near-infrared absorbing metal oxide particles (B) larger than 2 μm can be identified within a square 200 μm field of view.

[0107] Furthermore, compared with Comparative Example 4, which used phosphate ester as a dispersant, the near-infrared transmittance of the knitted fabrics obtained in Examples 3 and 4 was lower. This is presumably due to the excellent dispersibility of the near-infrared absorbing metal oxide particles (B) in the fibers.

[0108] On the other hand, in Comparative Example 3, the thermoplastic resin composition did not contain the modified maleic anhydride-styrene copolymer (A), and the dispersion of near-infrared absorbing metal oxide particles (B) was poor. Figure 2 shows an optical microscope image of the dispersion state of the thermoplastic resin composition obtained in Comparative Example 3. As shown in Figure 2, in the thermoplastic resin composition obtained in Comparative Example 3, many near-infrared absorbing metal oxide particles (B) larger than 2 μm can be identified in the same field of view.

[0109] In Comparative Examples 5-9, the thermoplastic resin composition contained a dispersant of unmodified maleic anhydride-styrene copolymer (A), and the near-infrared absorbing metal oxide particles (B) in the thermoplastic resin composition had poor dispersibility. In Comparative Example 4, the thermoplastic resin composition contained phosphate ester as a dispersant, and the IV retention rate was worse than in Examples 3 and 4. This is presumably because the pH of the phosphate ester is less than 5 and is 1.53, thus promoting hydrolysis in the thermoplastic resin composition, leading to a decrease in viscosity. [Simplified Explanation of the Diagram]

[0025] Figure 1 is a schematic diagram of an optical microscope image of the thermoplastic resin composition obtained in Example 3 during the evaluation of its dispersion state. Figure 2 is a schematic diagram showing an optical microscope image of the thermoplastic resin composition obtained in Comparative Example 3 during the evaluation of its dispersion state.

Claims

1. A thermoplastic resin composition comprising a modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and a thermoplastic resin (C), wherein the amount of modified maleic anhydride-styrene copolymer (A) added is 20 to 150 parts by mass relative to 100 parts by mass of the near-infrared absorbing metal oxide particles (B), and the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm in size within a 200 μm square field of view observed under a microscope is 50 or less, wherein the near-infrared absorbing metal oxide particles (B) are surface modified by a dispersant (b) having a polar group, and at least a portion of the modified maleic anhydride-styrene copolymer (A) is bonded to the near-infrared absorbing metal oxide particles (B) via the dispersant (b).

2. The thermoplastic resin composition as claimed in claim 1, wherein the modified maleic anhydride-styrene copolymer (A) has a weight average molecular weight of 1,000 to 20,000.

3. The thermoplastic resin composition as claimed in claim 1, wherein the near-infrared absorbing metal oxide particles (B) are one or more selected from the group consisting of cesium tungsten oxide, indium tin oxide, and antimony tin oxide.

4. The thermoplastic resin composition as claimed in claim 1, characterized in that the thermoplastic resin (C) is one or more selected from the group consisting of polyester resins, polyamide resins and polyurethane resins.

5. A molded article, which is a melt-molded article of a thermoplastic resin composition as claimed in claim 1 or 2.

6. A method for manufacturing a thermoplastic resin composition, comprising the following steps: mixing modified maleic anhydride-styrene copolymer (A), near-infrared absorbing metal oxide particles (B), and thermoplastic resin (C), and performing melt mixing at a temperature above the melting point of the thermoplastic resin (C), wherein in the method for manufacturing the thermoplastic resin composition, the amount of modified maleic anhydride-styrene copolymer (A) added is 20 to 150 parts by mass relative to 100 parts by mass of the near-infrared absorbing metal oxide particles (B), and the number of near-infrared absorbing metal oxide particles (B) exceeding 2 μm in a square field of view observed under a microscope is 50 or less, the near-infrared absorbing metal oxide particles (B) are surface modified by a dispersant (b) having polar groups, and at least a portion of the modified maleic anhydride-styrene copolymer (A) is bonded to the near-infrared absorbing metal oxide particles (B) via the dispersant (b).

7. A method for manufacturing a thermoplastic resin composition as claimed in claim 6, comprising the step of preparing an aqueous dispersion of the near-infrared absorbing metal oxide particles (B), and mixing the modified maleic anhydride-styrene copolymer (A), the aqueous dispersion of the near-infrared absorbing metal oxide particles (B), and the thermoplastic resin (C).

8. A method for manufacturing a thermoplastic resin composition as claimed in claim 6, wherein the modified maleic anhydride-styrene copolymer (A) has a weight average molecular weight of 1,000 to 20,000.

9. A method for manufacturing a thermoplastic resin composition as claimed in claim 6, wherein the pH of the modified maleic anhydride-styrene copolymer (A) is 5 to 9 when it is prepared into a 10% by mass aqueous solution.

10. A method for manufacturing a thermoplastic resin composition as claimed in claim 6, wherein the near-infrared absorbing metal oxide particles (B) are selected from one or more of the group consisting of cesium tungsten oxide, indium tin oxide, and antimony tin oxide.

11. A method for manufacturing a thermoplastic resin composition as claimed in claim 6, wherein the thermoplastic resin (C) is selected from one or more of the group consisting of polyester resins, polyamide resins and polyurethane resins.

12. A method for manufacturing a molded article, comprising the step of: melt molding a thermoplastic resin composition obtained by the manufacturing method as described in claim 6.

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