Recycled resin compositions, resin molded products, resin housings, and electronic devices

Abstract

The object of the present invention is to provide a recycled resin composition, resin molded articles, resin housings, and electronic devices that are substantially free of harmful substances, have high impact strength, and are excellent in flame retardancy. [Solution] A recycled resin composition comprising a PCR material containing polycarbonate and a core-shell type impact modifier, wherein the core-shell type impact modifier contains silicone rubber, and the fluororesin content in the recycled resin composition is less than 1000 ppm.

Description

Technical Field

[0001] The present invention relates to a recycled resin composition, a resin molded product, a resin housing, and an electronic device. More specifically, it relates to a recycled resin composition, a resin molded product, a resin housing, and an electronic device having high impact strength and excellent flame retardancy.

Background Art

[0002] In recent years, PFAS regulations regarding products such as resin molded products have been strengthening, but many of these products contain harmful substances such as fluororesins like polytetrafluoroethylene. And for such products, it is required to contain as few harmful substances such as fluororesins as possible. Hereinafter, "polytetrafluoroethylene" will be abbreviated as "PTFE".

[0003] Here, flame retardancy is required for resin molded products, and some are required to comply with a standard called V-0, which is the standard name defined by UL (Underwriters Laboratories) in the United States and used in the evaluation of such flame retardancy. Hereinafter, such a standard will be described by omitting it as the "V-0 standard".

[0004] For resin molded products required to comply with the V-0 standard, from the viewpoints of the impact on the human body and environmental protection, flame retardants and drip preventives are often used to ensure flame retardancy during the manufacture of the resin molded products.

[0005] For drip preventives, basically PTFE and its processed products are used to ensure flame retardancy, and currently, resin molded products as described above contain a large amount of harmful substances such as fluororesins.

[0006] For example, for electronic device housings that require excellence in both flame retardancy and impact strength, technologies such as those disclosed in Patent Document 1 have been disclosed. Furthermore, as disclosed in Patent Document 2, a technology for applying a treatment to prevent deterioration from the initial performance of a resin composition made from PCR material containing polycarbonate has been disclosed, but there is still room for improvement in these technologies. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-21441 [Patent Document 2] Japanese Patent Publication No. 2000-103952 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In the technology disclosed in Patent Document 1, flame retardancy and impact strength are improved by using a core-shell type impact modifier containing a flame retardant and silicone rubber in polycarbonate. The flame retardant used is phosphorus-based, and the core-shell type impact modifier containing silicone rubber uses a silicone-acrylic composite rubber core that also acts as a flame retardant aid in addition to the role of an impact modifier.

[0009] However, in order to manufacture electronic equipment enclosures that comply with the V-0 standard using the technologies described above, drip inhibitors containing harmful substances such as fluororesins like PTFE are currently essential. Therefore, there is a need for alternative technologies to ensure flame retardancy, but currently there is a lack of suitable alternative technologies.

[0010] Furthermore, in the manufacture of resin molded products and the like, biomass production and recycling are important for reducing carbon emissions, and technological development is actively progressing alongside legal regulations and promotional measures. In particular, the utilization of post-consumer recycled materials collected after use is important. Hereinafter, "post-consumer recycled materials" will also be referred to as "PCR materials." Hereinafter, in this specification, used recycled materials collected after being used in the market will be abbreviated as "PCR materials."

[0011] Generally, products manufactured using PCR materials experience significant degradation from their initial performance before being converted into PCR materials, thus limiting the applications of PCR materials.

[0012] The technology disclosed in Patent Document 2 describes a resin composition made using a PCR material containing polycarbonate as a raw material, which is treated to prevent degradation from its initial performance. Furthermore, it is stated that the resin composition in this technology can withstand accelerated degradation tests and pulverization-remolding tests when virgin resin is included as a raw material. Hereinafter, "resin composition made using a PCR material containing polycarbonate as a raw material" will also be referred to as "PCR polycarbonate material resin composition".

[0013] However, in reality, the above-mentioned PCR polycarbonate resin composition shows degradation from its initial performance, with a particularly significant decrease in toughness function, and therefore cannot be considered to have practical performance.

[0014] Currently, there are few technologies that can elevate PCR polycarbonate resin compositions like those described above to practical performance levels, and these are insufficient to meet the diverse needs of the market.

[0015] In order to improve the performance of PCR polycarbonate resin compositions to a practical level, it is conceivable to include halogenated flame retardants, which are widely known and have a strong effect. However, halogenated flame retardants are mainly brominated, which poses an environmental problem.

[0016] For the reasons stated above, it is preferable that hazardous substances such as PTFE and halogenated flame retardants are not included in PCR polycarbonate resin compositions from an environmental protection standpoint. However, the raw materials for these PCR polycarbonate resin compositions are recalled products from the market. Therefore, it is not practical to manufacture PCR polycarbonate resin compositions with zero content of PTFE and halogenated flame retardants, which are widely used in products on the market.

[0017] Therefore, there is a need for a PCR polycarbonate resin composition that has high impact strength and excellent flame retardancy, even if it is substantially free of harmful substances such as PTFE and halogenated flame retardants. In this specification, "substantially free of harmful substances" means that the amount of fluororesin, bromine, and chlorine is each less than 1000 ppm.

[0018] This invention has been made in view of the above-mentioned problems and circumstances, and its objective is to provide a recycled resin composition, resin molded product, resin housing, and electronic device that are substantially free of harmful substances, have high impact strength, and are excellent in flame retardancy. [Means for solving the problem]

[0019] In order to solve the above problems, the inventors investigated the causes of the above problems and found that the above problems can be solved by incorporating a core-shell type impact modifier containing silicone rubber into the PCR polycarbonate resin composition, and by setting the fluororesin content in the PCR polycarbonate resin composition to less than 1000 ppm, thus leading to the present invention. In other words, the above-mentioned problems of the present invention are solved by the following means. In this specification, "resin composition made using PCR material containing polycarbonate as a raw material," that is, "PCR polycarbonate material resin composition," is also simply referred to as "recycled resin composition."

[0020] 1. A recycled resin composition containing a PCR material containing polycarbonate and a core-shell type impact modifier, wherein the core-shell type impact modifier contains silicone rubber, and the content of the fluororesin in the recycled resin composition is less than 1000 ppm A recycled resin composition characterized by this.

[0021] 2. The core of the core-shell type impact modifier is a silicone-acrylic composite rubber, and the shell is composed of a resin having a structural unit derived from methyl methacrylate The recycled resin composition according to claim 1, characterized by this. [[ID=Is]]

[0022] 3. The content of the PCR material containing polycarbonate in the recycled resin composition is within the range of 88 to 96% by mass, and the content of the core-shell type impact modifier is within the range of 4 to 12% by mass The recycled resin composition according to claim 1, characterized by this.

[0023] 4. The total content of chlorine and bromine in the recycled resin composition is less than 1000 ppm The recycled resin composition according to claim 1, characterized by this.

[0024] 5. Composed of the recycled resin composition according to any one of claims 1 to 4 A resin molded product characterized by this.

[0025] 6. Including the resin molded product according to claim 5 A resin housing characterized by this.

[0026] 7. Equipped with the resin housing according to claim 6 [[ID=Is]] An electronic device characterized by this.

Advantages of the Invention

[0027] The above-described means of the present invention make it possible to provide recycled resin compositions, resin molded articles, resin housings, and electronic devices that are substantially free of harmful substances, have high impact strength, and are highly flame-retardant. Although the mechanism by which the effects of this invention manifest or the mechanism of action are not yet clear, we speculate as follows.

[0028] The recycled resin composition of the present invention is a recycled resin composition containing a PCR material containing polycarbonate and a core-shell type impact modifier, wherein the core-shell type impact modifier contains silicone rubber, and the fluororesin content in the recycled resin composition is less than 1000 ppm.

[0029] PCR materials containing polycarbonate are widely used as market-recovered products, and producing recycled resin compositions using them as raw materials is an important consideration from an environmental protection standpoint. The recycled resin composition of the present invention exhibits excellent flame retardancy even when using PCR materials containing polycarbonate with a fluororesin content of less than 1000 ppm as a raw material.

[0030] Furthermore, by incorporating a core-shell type impact modifier containing silicone rubber into the recycled resin composition, it becomes possible to achieve high impact strength. [Modes for carrying out the invention]

[0031] The present invention, its components, and embodiments and models for carrying out the present invention will be described in detail below. In this application, "~" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0032] While the advantages and features provided by one or more embodiments of the present invention will be better understood from the following detailed description and accompanying drawings, these drawings are for illustrative purposes only and are not intended to define any limitations of the present invention.

[0033] 1. Recycled resin composition The recycled resin composition of the present invention is characterized by containing a PCR material containing polycarbonate and a core-shell type impact modifier, wherein the core-shell type impact modifier contains silicone rubber and the fluororesin content is less than 1000 ppm.

[0034] (1.1) Inclusions (PCR material containing polycarbonate) The "PCR material containing polycarbonate" according to the present invention is a raw material for the recycled resin composition of the present invention, and is a market-recovered resin recovered from molded products using polycarbonate as a base material. It should be noted that such market-recovered resins typically contain resins other than polycarbonate, and strictly speaking, PCR materials containing polycarbonate also include substances that are not resins.

[0035] There are no particular restrictions on the proportion of polycarbonate in the PCR material according to the present invention; it is sufficient as long as polycarbonate is the main component.

[0036] In this specification, "virgin polycarbonate" refers to polycarbonate material before it is molded into a product, and is not a recycled resin from the market. Virgin polycarbonate itself is usually sold as pellets consisting only of virgin polycarbonate. Pellets of virgin polycarbonate resin compositions with added additives such as colorants, antioxidants, and flame retardants are also sold. These pellets are fed into a molding machine to produce resin molded products.

[0037] There are no particular restrictions on the proportion of polycarbonate in the virgin polycarbonate resin composition; it is sufficient as long as polycarbonate is the main component.

[0038] Virgin polycarbonate is a resin with excellent impact resistance in its initial performance, but it is also a material that deteriorates rapidly due to its poor fluidity and susceptibility to hydrolysis. Furthermore, while virgin polycarbonate alone can exhibit flame retardancy of around V-2, increasing its flame retardancy to V-0 requires the inclusion of PTFE containing harmful substances or flame retardants.

[0039] However, even without virgin polycarbonate, the recycled resin composition of the present invention contains a PCR material containing polycarbonate, which makes it possible to improve flame retardancy to V-0 without including the above-mentioned PTFE or flame retardants. Furthermore, the impact strength is improved by including a core-shell type impact modifier containing silicone rubber in the recycled resin composition.

[0040] Furthermore, when PTFE containing harmful substances and flame retardants are not used, the recycled resin composition of the present invention, which contains PCR material containing polycarbonate, can be said to have superior flame retardancy compared to resin compositions containing virgin polycarbonate.

[0041] The impact strength of resin compositions based on PCR material and those based on virgin polycarbonate varies depending on the required grade of the resin composition and cannot be determined universally.

[0042] For example, in a resin composition based on PCR material, the impact strength is higher than that of a resin composition based on virgin polycarbonate, so it can be adjusted to achieve the impact strength required for the above grade so that it is practically acceptable.

[0043] Furthermore, in resin compositions based on virgin polycarbonate, when virgin polycarbonate with particularly high impact strength is used, adding the core-shell type impact modifier may actually decrease the impact strength, but the decrease in impact strength can be kept within a range that does not pose a practical problem.

[0044] In the recycled resin composition, it is preferable that the total content of the PCR material containing the polycarbonate and the core-shell type impact modifier is 50% by mass or more, and that the content ratio of the PCR material containing the polycarbonate and the core-shell type impact modifier is within the range of 88:12 to 96:4.

[0045] This results in improved impact strength and superior flame retardancy.

[0046] (Core-shell type impact modifier) Generally, impact modifiers used in combination with flame retardants have a core-shell shape, from the viewpoint of dispersibility of the impact modifier during manufacturing.

[0047] There are no particular restrictions on the core-shell type impact modifier, but it is preferably a core-shell type elastomer, and it may be used alone or in combination of two or more types. Using a core-shell type elastomer further increases impact strength. It mitigates the effects of external impacts such as bending and impact during actual use, resulting in good reliability during long-term use.

[0048] The elastomer may be a styrene-based elastomer. Examples of styrene-based elastomers include block copolymers of a styrene component with butadiene, isoprene, 1,3-pentadiene, etc. Modified versions of these or hydrogenated versions may also be used. More specifically, examples include SBS, SIS, SEBS, and SEPS.

[0049] The elastomer may be anything other than a styrene-based elastomer. Examples of styrene-based elastomers include polyester-based elastomers, polyolefin-based elastomers, diene-based elastomers, and acrylic-based elastomers. Other known examples include polyamide-based elastomers, polyurethane-based elastomers, fluorine-based elastomers, and silicone-based elastomers.

[0050] The elastomer is generally a thermoplastic elastomer. Preferably, the elastomer is a polyester-based elastomer or the styrene-based elastomer described above.

[0051] A core-shell type elastomer consists of an innermost layer (i.e., a core) and one or more outer layers (i.e., a shell) covering it. Preferably, the core-shell type elastomer is a core-shell type graft copolymer in which monomer components capable of graft copolymerization with respect to the core are graft copolymerized as the shell.

[0052] Core-shell type graft copolymers typically have a polymer component called a rubber component as the core. In core-shell type graft copolymers, it is preferable that the polymer component constituting the core and monomer components copolymerizable with this polymer component are graft copolymerized as the shell.

[0053] Examples of polymer components that form the core include butadiene-based rubbers such as polybutadiene and styrene-butadiene copolymers, isoprene-based rubbers, acrylic-based rubbers such as polybutyl acrylate, poly(2-ethylhexyl acrylate), and butyl acrylate-2-ethylhexyl acrylate copolymers, silicone-based rubbers such as polyorganosiloxane rubber, butadiene-acrylic composite rubbers, silicone-acrylic composite rubbers such as IPN (Interpenetrating Polymer Network) type composite rubbers consisting of polyorganosiloxane rubber and polyalkyl acrylate rubber, ethylene-α-olefin-based rubbers such as ethylene-propylene copolymer, ethylene-butene copolymer, and ethylene-octene copolymer, ethylene-acrylic rubber, and fluororubber. These may be used individually or in combination of two or more.

[0054] Among these, at least one selected from butadiene rubber, acrylic rubber, silicone rubber, and silicone-acrylic composite rubber is preferred in terms of mechanical properties and surface appearance, with silicone-acrylic composite rubber being more preferred.

[0055] The core-shell type impact modifier according to the present invention contains silicone rubber, which reflects the flame retardancy and sliding properties of the silicone material, and is expected to improve the flame retardancy and moldability of the resin composition.

[0056] Examples of monomer components that can be graft copolymerized with the polymer component of the core and constitute the shell include aromatic vinyl compounds; vinyl cyanide compounds; (meth)acrylic compounds such as (meth)acrylic acid ester compounds, (meth)acrylic acid compounds, and epoxy group-containing (meth)acrylic acid ester compounds such as glycidyl (meth)acrylate; maleimide compounds such as maleimide, N-methylmaleimide, and N-phenylmaleimide; and α,β-unsaturated carboxylic acid compounds such as maleic acid, phthalic acid, and itaconic acid, and their anhydrides (e.g., maleic anhydride). These monomer components may be used individually or in combination of two or more.

[0057] Among these, aromatic vinyl compounds, vinyl cyanide compounds, and (meth)acrylic compounds are preferred in terms of mechanical properties and surface appearance, and more preferably aromatic vinyl compounds and (meth)acrylic compounds, with (meth)acrylic acid ester compounds being the most preferred.

[0058] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, 1-vinylnaphthalene, 4-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, and 4-dodecylstyrene. Other examples include 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, and halogenated styrenes. Among these, styrene or α-methylstyrene is more preferred.

[0059] Examples of (meth)acrylic acid ester compounds include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, and octyl (meth)acrylate. Among these, methyl (meth)acrylate and ethyl (meth)acrylate are preferred because they are relatively easy to obtain, with methyl (meth)acrylate being more preferred. Note that "(meth)acrylic" is a general term for "acrylic" and "methacrylic".

[0060] As the core of the core-shell type elastomer, at least one polymer component selected from butadiene rubber, acrylic rubber, silicone rubber, and silicone-acrylic composite rubber is preferred. A core-shell type graft copolymer is particularly preferred, consisting of a shell formed by graft copolymerizing a (meth)acrylic compound such as a (meth)acrylic acid ester or an aromatic vinyl compound around the core.

[0061] In core-shell type graft copolymers, the content of the polymer component of the core is preferably 40% by mass or more.

[0062] Furthermore, the total content of (meth)acrylic compound components and aromatic vinyl compound components in the shell of the core-shell type graft copolymer is preferably 30% by mass or more. Among the (meth)acrylic compounds, (meth)acrylic acid esters are particularly preferred.

[0063] In the shell, either (meth)acrylic compounds or aromatic vinyl compounds may be used alone, or they may be used in combination.

[0064] Based on the above, a silicone-acrylic composite rubber is preferred as the core of the core-shell type impact modifier according to the present invention, thereby increasing the impact strength of the recycled resin composition. Furthermore, the shell of the core-shell type impact modifier is preferably composed of a resin having structural units derived from methyl methacrylate.

[0065] Preferred core-shell type elastomers include methyl methacrylate-butadiene-styrene copolymer (MBS), methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS), methyl methacrylate-butadiene copolymer (MB), methyl methacrylate-acrylic rubber copolymer (MA), methyl methacrylate-acrylic rubber-styrene copolymer (MAS), methyl methacrylate-acrylic-butadiene rubber copolymer, methyl methacrylate-acrylic-butadiene rubber-styrene copolymer, and methyl methacrylate-(silicone-acrylic composite rubber) copolymer.

[0066] From the viewpoint of achieving the effects of the present invention, it is preferable that the content of the core-shell type impact modifier in the recycled resin composition be within the range of 4 to 12% by mass.

[0067] (hazardous substances) The recycled resin composition of the present invention preferably does not contain harmful substances. Specifically, the fluororesin content in the recycled resin composition may be less than 1000 ppm. Furthermore, the total content of chlorine and bromine in the recycled resin composition is preferably less than 1000 ppm.

[0068] The amount of harmful substances contained in the recycled resin composition of the present invention depends on the amount used in the PCR material recovered from the market, and can be controlled to a certain extent by limiting the types of recovered materials or by sorting based on inspections using a fluorescent X-ray analyzer or the like.

[0069] (others) The recycled resin composition may contain flame retardants and other additives, to the extent that they do not impair the effects of the present invention, and various known additives can be used for these.

[0070] The effects of the present invention are further enhanced when the total content of the polycarbonate-containing PCR material and the core-shell type impact modifier in the recycled resin composition of the present invention is 50% by mass or more, and the content ratio of the polycarbonate-containing PCR material to the core-shell type impact modifier is within the range of 88:12 to 96:4. As a result, the recycled resin composition has sufficient impact strength to be used as a housing component for electronic equipment and also has excellent flame retardancy.

[0071] (1.2) Method of analysis of contained substances The contents of recycled resin compositions can be analyzed by various known methods. Known methods include, for example, wavelength-dispersive X-ray spectroscopy (WDX), energy-dispersive X-ray spectroscopy (EDS), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR).

[0072] Furthermore, the core-shell type impact modifier containing the above-mentioned silicone rubber is detected as a rubbery polymer mainly composed of a composite rubber made from silicone rubber components during material analysis. In addition, whether or not a PCR material containing polycarbonate is used in the recycled resin composition of the present invention can be easily confirmed by the published values ​​of the manufacturer of the material actually used.

[0073] 2.Resin molded products The resin molded article according to the present invention is characterized by being molded using the above-mentioned recycled resin composition. By forming the resin molded article using the above-mentioned recycled resin composition, high impact strength and excellent flame retardancy can be imparted to the resin molded article.

[0074] The recycled resin composition according to the present invention contains polycarbonate, which is a thermoplastic resin. Thermoplastic resins can be molded into desired shapes using known injection molding machines and are easy to handle. Therefore, by molding them into appropriate forms and shapes, they can be used as housings and components in electronic devices and the like.

[0075] As for the molding method of the resin molded product according to the present invention, various known methods can be appropriately selected depending on the form and application of the molded product. For example, one method is to melt the recycled resin composition in various molding machines and then mold it.

[0076] A preferred method for preparing a recycled resin composition as a suitable molding material by adding additives and homogenizing it is, for example, the melt-kneading method. Examples of melt-kneading methods include pre-mixing the resin, polysaccharide-containing nanoparticles, and other additives using various mixers such as tumblers and high-speed mixers known as Henschel mixers, followed by melt-kneading using a kneading device such as a Banbarri mixer, roll mixer, plastograph, single-screw extruder, twin-screw extruder, or kneader.

[0077] In particular, from the viewpoint of production efficiency, it is preferable to use an extruder, and more preferable to use a twin-screw extruder. The material can be melted and kneaded using an extruder, the kneaded material can be extruded into strands, and then the kneaded material can be processed into pellets.

[0078] It is preferable to thoroughly dry each material before pre-mixing. The drying temperature is not particularly limited, but is preferably in the range of 60 to 120°C. The drying time is not particularly limited, but is preferably in the range of 2 to 6 hours. Furthermore, drying under reduced pressure is preferable from the viewpoint of promoting faster drying. The above drying may be performed after pre-mixing.

[0079] The melt-mixing temperature is not particularly limited, but it is preferable to select it appropriately depending on the type of resin used, and specifically, it is preferable to be in the range of 150 to 280°C. Here, the melt-mixing temperature corresponds to, for example, the cylinder temperature in a mixing device such as a twin-screw extruder. Furthermore, if there are multiple temperature settings in the cylinder of the mixing device, the cylinder temperature refers to the temperature of the cylinder with the highest temperature. The mixing pressure is not particularly limited, but it is preferable to be in the range of 1 to 20 MPa.

[0080] The discharge rate from a mixing device varies greatly depending on the size of the mixing machine used and the composition of the materials being mixed. For example, the smallest class of laboratory mixers discharges 100g to 1kg / hr, while larger ones discharge 200 to 500kg / hr.

[0081] The kneaded material, melted and kneaded in the kneading apparatus using the method described above, is preferably subjected to a cooling treatment after being extruded from the kneading apparatus. The method of cooling is not particularly limited and includes, for example, immersing the kneaded material in water in the range of 0 to 60°C for water cooling, cooling with gas in the range of -40 to 60°C, or contacting it with metal in the range of -40 to 60°C.

[0082] The form and shape of the recycled resin composition of the present invention are not particularly limited, and may be in solid form such as powder, granules, tablets, pellets, flakes, or fibers, or in liquid form.

[0083] The resin molded products are not particularly limited and include, for example, parts for home appliances and automobiles (electrical and electronic components, electrical components, exterior parts, interior parts, etc.), various packaging materials, household goods, office supplies, piping, agricultural materials, etc.

[0084] 3. Resin housings and electronic equipment The resin housing according to the present invention is characterized by including the aforementioned resin molded product. Furthermore, the electronic device according to the present invention is characterized by comprising the aforementioned resin molded product. That is, the aforementioned resin molded product may be used in electronic devices, etc., either as a housing for the electronic device or as a component. In this invention, "electronic device" refers to an electrical product that applies the technology of electronics.

[0085] The articles housed in the resin housing according to the present invention are not particularly limited, but it is preferable to house electronic devices and the like. In addition, the resin housing of the present invention can also be applied to housings that are generally preferably made of flame-retardant resin.

[0086] Electronic devices are not particularly limited and include, for example, computers, scanners, copiers, printers, facsimile machines, office automation equipment such as MFPs (Multi-Function Peripherals) that combine these functions, and digital printing systems for commercial printing. [Examples]

[0087] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples, the units "parts" or "%" are used, and unless otherwise specified, they represent "parts by mass" or "mass%".

[0088] A. Preparation of resin compositions (A.1) Resin composition [1] As raw materials, pelletized PCR material was dried at 120°C for 2 hours and designated as PCR material [1]. This PCR material [1] was derived from an optical disc containing polycarbonate.

[0089] The PCR material [1] and the core-shell type impact modifier "METABLEN SX-005" manufactured by Mitsubishi Chemical Corporation were dry-blended and placed in a twin-screw mixer, where melt mixing was performed under conditions of 240°C and 400 rpm. The weight ratio of PCR material [1] to the core-shell type impact modifier was 96:4.

[0090] Furthermore, the above-mentioned "METABLEN SX-005" is a core-shell type impact modifier in which the core is a silicone-acrylic composite rubber and the shell is made of a resin having structural units derived from methyl methacrylate.

[0091] Based on the above, a strand of molten resin [1] was prepared.

[0092] The strand [1] was cooled and then subjected to a pelletizer to produce a resin composition [1], which is a resin composition pellet.

[0093] (A.2) Resin composition [2] The raw materials and core-shell type impact modifier were the same as those used in resin composition [1]. These were dry-blended and fed into a twin-screw mixer, where melt-mixing was performed under conditions of 240°C and 400 rpm. However, the weight ratio of PCR material [1] to core-shell type impact modifier was 93:7.

[0094] Based on the above, a strand of molten resin [2] was prepared.

[0095] The strand [2] was cooled and then subjected to a pelletizer to produce resin composition [2], which is a resin composition pellet.

[0096] (A.3) Resin composition [3] The raw materials and core-shell type impact modifier were the same as those used in resin composition [1]. These were dry-blended and fed into a twin-screw mixer, where melt-mixing was performed under conditions of 240°C and 400 rpm. However, the weight ratio of PCR material [1] to core-shell type impact modifier was 88:12.

[0097] Based on the above, a strand of molten resin [3] was prepared.

[0098] The strands [3] were cooled and then subjected to a pelletizer to produce resin composition [3], which is a resin composition pellet.

[0099] (A.4) Resin composition [4] As raw materials, virgin material containing pelletized polycarbonate was prepared by drying it at 120°C for 2 hours, and this was designated as virgin material [1].

[0100] Virgin material [1] and "METABLEN SX-005," a core-shell type impact modifier manufactured by Mitsubishi Chemical Corporation, were dry-blended and fed into a twin-screw mixer. Melt-mixing was performed under conditions of 240°C and 400 rpm. The weight ratio of virgin material [1] to the core-shell type impact modifier was 96:4.

[0101] Based on the above, a strand of molten resin [4] was prepared.

[0102] The strands [4] were cooled and then subjected to a pelletizer to produce resin composition [4], which is a resin composition pellet.

[0103] (A.5) Resin composition [5] The raw materials and core-shell type impact modifier were the same as those used in the resin composition [4], and these were dry-blended and fed into a twin-screw mixer. Melt-mixing was performed under the conditions of 240°C and 400 rpm. However, the weight ratio of virgin material [1] to core-shell type impact modifier was 88:12.

[0104] Based on the above, a strand of molten resin [5] was prepared.

[0105] The strands [5] were cooled and then subjected to a pelletizer to produce resin composition [5], which is a resin composition pellet.

[0106] (A.6) Resin composition [6] The PCR material [1] was placed in a twin-screw mixer and melt-mixed under the conditions of 240°C and 400 rpm.

[0107] Based on the above, a strand of molten resin [6] was prepared.

[0108] The strands [6] were cooled and then subjected to a pelletizer to produce resin composition [6], which is a resin composition pellet.

[0109] (A.7) Resin composition [7] Virgin material [1] was fed into a twin-screw mixer and melt-mixed under the conditions of 240°C and 400 rpm.

[0110] Based on the above, a strand of molten resin [7] was prepared.

[0111] The strands [7] were cooled and then subjected to a pelletizer to produce resin composition [7], which is a resin composition pellet.

[0112] B. Evaluation and determination of flame retardancy The flame retardancy was evaluated by conducting the UL94V test. The "UL94 test" is a combustion test for plastic materials used in equipment components, as defined by Underwriters Laboratories (UL) in the United States. The "UL94V test" evaluates flame retardancy based on the afterflame time and drip rate after exposing a test piece of a specified size, held vertically, to a burner flame for 10 seconds.

[0113] Specifically, each resin composition was dried at 80°C for 4 hours, and then, using a J55ELII injection molding machine manufactured by Japan Steel Works Ltd., strip-shaped test pieces measuring 125 mm × 13 mm × 2.4 mm were molded for each composition at a cylinder temperature of 280°C and a mold temperature of 80°C. The strip-shaped test pieces of resin compositions [1] to [7] molded in this manner were designated as UL combustion test pieces [1] to [7].

[0114] UL combustion test specimens of each molded resin composition were conditioned for 48 hours in a constant temperature chamber at 23°C and 50% humidity. Flame retardancy was evaluated in accordance with the UL94 test, and each UL combustion test specimen was classified as V-0, V-1, or V-2 based on its combustion behavior.

[0115] C. Impact strength evaluation After pre-drying each resin composition at 120°C for 2 hours, they were placed in an injection molding machine to produce Charpy impact test specimens with notches, measuring 80 mm × 10 mm × 4 mm, in accordance with JIS-K7111-1 (ISO179-1). The impact test specimens produced using resin compositions [1] to [7] were designated as Charpy impact test specimens [1] to [7].

[0116] The impact strength of Charpy impact test specimens [1] to [7] was calculated by performing notched Charpy impact tests and evaluated according to the following evaluation criteria.

[0117] (Evaluation Criteria) Passed (no practical problems). Impact strength: 15 kJ / m 2 That's all. Failed (Practical problems exist) Impact strength: 15kJ / m 2 It is less than.

[0118] D. Detection of hazardous substances Fluorine (F), bromine (Br), and chlorine (Cl) were detected in each resin composition using wavelength-dispersive X-ray spectroscopy (WDX) with Rigaku's "ZSXPrimusIV". Since this WDX system can detect elements down to approximately 200 ppm, if fluorine, bromine, and chlorine were not detected, it can be assumed that their levels were below 1000 ppm. However, since this WDX system cannot detect elements below 1000 ppm, if fluorine, bromine, and chlorine were not detected, it can be assumed that their levels were below 1000 ppm. E. Summary Table I summarizes the raw materials, impact modifiers, weight ratios of raw materials to impact modifiers, and the evaluation results for each resin composition.

[0119] [Table 1]

[0120] From the results in Table I above, it can be seen that the resin composition made from PCR material containing polycarbonate according to the present invention, i.e., the recycled resin composition, has superior flame retardancy compared to the resin composition made from virgin polycarbonate.

[0121] Specifically, when a core-shell type impact modifier containing silicone rubber is included, the resin composition made from virgin polycarbonate only meets the V-2 standard in flame retardancy evaluation. In contrast, the resin composition made from PCR material containing polycarbonate according to the present invention, i.e., the recycled resin composition, meets the V-0 standard in flame retardancy evaluation when a core-shell type impact modifier containing silicone rubber is included.

[0122] Furthermore, it is evident that the inclusion of a core-shell type impact modifier containing silicone rubber in the recycled resin composition results in impact strength that is practically acceptable.

[0123] Although embodiments of the present invention have been described and illustrated in detail above, the disclosed embodiments are illustrative and for illustrative purposes only and are not limiting. The scope of the present invention should be interpreted by the terms of the appended claims.

Claims

1. A recycled resin composition containing a PCR material containing polycarbonate and a core-shell type impact modifier, The aforementioned core-shell type impact modifier contains silicone rubber, The fluororesin content in the recycled resin composition is less than 1000 ppm. A recycled resin composition characterized by the following features.

2. In the aforementioned core-shell type impact modifier, the core is a silicone-acrylic composite rubber, and the shell is composed of a resin having structural units derived from methyl methacrylate. The recycled resin composition according to claim 1.

3. The total content of the PCR material containing the polycarbonate and the core-shell type impact modifier in the recycled resin composition is 50% by mass or more, and the content ratio of the PCR material containing the polycarbonate and the core-shell type impact modifier is within the range of 88:12 to 96:

4. The recycled resin composition according to claim 1.

4. The total content of chlorine and bromine in the recycled resin composition is less than 1000 ppm. The recycled resin composition according to claim 1, characterized in that...

5. Composed of a recycled resin composition according to any one of claims 1 to 4 A resin molded product characterized by the following features.

6. Includes the resin molded article described in claim 5 A resin housing characterized by the following features.

7. The resin housing is provided according to claim 6. An electronic device characterized by the following features.

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