Synthetic resin composition comprising recycle plastics

Abstract

The present invention is intended to provide a thermoplastic polymer composition for injection-molded parts of junction blocks and wiring harnesses among automotive parts. To this end, the present invention discloses a molding resin composition using recycled plastic comprising, based on the total weight of the molding resin composition, 42 to 45 weight% of aliphatic polyamide resin PA66 (Polyamide 66), 39 to 41 weight% of aliphatic polyamide resin recycled PA6 (Recycled Polyamide 6), 6 to 7 weight% of impact modifier, 3.5 to 4.5 weight% of linear low-density polyethylene, 3.5 to 4.5 weight% of low-density polyethylene, 0.35 to 0.4 weight% of antioxidant, 0.25 to 0.3 weight% of release agent, 0.25 to 0.3 weight% of flowability improver, and 1 to 1.2 weight% of heat-resistant masterbatch.

Description

Technology Field

[0001] The present invention relates to a synthetic resin composition containing recycled plastic components, and more specifically, to a molding resin composition using recycled plastic to satisfy the mechanical and physical properties required by the Material Specification for the performance of thermoplastic polymer materials for injection-molded parts of junction blocks and wiring harnesses among automotive parts. Background Technology

[0002] As plastic emerges as a major cause of environmental pollution worldwide, there is a growing demand for so-called PCR (Post-Consumer Recycled) plastic, a material made by sorting, collecting, and recycling plastic products used and discarded by end consumers, as an alternative to reduce carbon emissions.

[0003] Plastic recycling methods can be broadly classified into mechanical, chemical, and thermal recycling. Mechanical recycling involves reprocessing collected waste plastics by altering only their physical form without changing their chemical structure, separating them into materials that are as similar as possible to the original plastics. Chemical recycling involves regenerating waste plastics into raw materials by altering their molecular structure itself, while thermal recycling utilizes the high calorific value of waste plastics to recover thermal energy for use as fuel.

[0004] In particular, mechanical recycling is the most representative and long-used method for recycling plastics; it involves crushing collected waste plastic, washing it, and melting it down to create recycled pellets, which are then mixed (compounded) with virgin raw materials in a specific ratio to produce the final product.

[0005] Meanwhile, the European Union (EU) launched the End-of-Life Vehicles Regulation (ELV) in 2023, which imposes mandatory use of recycled materials in the automotive sector. According to the regulations, at least 25% of the plastics used in future automobile manufacturing must be recycled PCR plastic.

[0006] However, since PCR plastic recycled materials used for automotive parts have significantly poor moldability, impact resistance, and thermal deformation resistance, there is a problem in that it is very difficult to obtain molded products that meet or exceed the quality standards required by the Material Specification using molding methods such as injection molding or extrusion molding.

[0007] For example, recycled polyamide 6 (PA6) has a problem in that the amide groups (-NH-CO-) contained in the resin react with moisture present in the air, causing thermal decomposition or hydrolysis during the remelting process, which leads to a decrease in molecular weight and a significant deterioration in heat resistance and mechanical properties.

[0008] In addition, when glass fibers are added as a filler to improve the mechanical strength, heat resistance, and dimensional stability of recycled PA6 resin, there is a problem in that the glass fibers break due to high processing temperatures and shear stress during the process of obtaining molded products by extrusion or injection molding.

[0009] Meanwhile, among crystalline polyamides, representative PA6 and PA66 exhibit high mechanical properties as homopolymers alone, and can be produced as polymers with desired mechanical properties by changing the manufacturing method as needed; however, because nylon is fundamentally weak against external impact due to its characteristics, impact modifiers are used to increase impact strength.

[0010] It is stated that the background technology or prior art described herein refers to information possessed by the inventor or acquired during the process of deriving and completing the present invention, and is specified merely to aid in understanding the technical significance of the present invention and to be useful for prior art search and examination, and does not mean technology that was generally known and widely used in the technical field to which the invention belongs prior to the filing of the present invention. Prior art literature

[0011] KR 10-1548048 B1 2015. 08. 21.KR 10-1848775 B1 2018. 04. 09.KR 10-0566065 B1 2006. 03. 23.KR 10-2013-0009212 A 2013. 01. 23.KR 10-2020-0072610 A 2020. 06. 23. The problem to be solved

[0012] Accordingly, the inventors of the present invention, while comprehensively considering the aforementioned matters and with the idea of ​​resolving the technical limitations and problems of existing synthetic resins for molding containing PCR plastic components, have devised the present invention as a result of tireless research and strenuous efforts to develop a molding resin composition using recycled plastic that satisfies the mechanical and physical properties required by the Material Specification for the performance and quality of thermoplastic polymer materials for injection-molded parts such as junction blocks and wiring harnesses in automobiles, and furthermore, can obtain a molded product with excellent processability, mechanical strength, and thermal deformability that satisfies the quality conditions of the Material Specification even when molded using molding methods such as injection molding or extrusion molding.

[0013] Therefore, the technical problem and objective of the present invention is to provide a molding resin composition using recycled plastic that can satisfy the standard specifications (MS941-07) for thermoplastic polymer materials for automotive parts.

[0014] The technical problems and objectives that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems and objectives will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0015] A specific means according to an aspect of the present invention for effectively achieving a specific technical purpose while embodying a new concept to solve the technical problem of the present invention as described above is provided for a molding resin composition using recycled plastic, characterized by comprising, based on the total weight of the molding resin composition, 42-45% by weight of aliphatic polyamide resin PA66 (Polyamide 66), 39-41% by weight of aliphatic polyamide resin recycled PA6 (Recycled Polyamide 6), 6-7% by weight of impact modifier, 3.5-4.5% by weight of linear low-density polyethylene, 3.5-4.5% by weight of low-density polyethylene, 0.35-0.4% by weight of antioxidant, 0.25-0.3% by weight of release agent, 0.25-0.3% by weight of flowability improver, and 1-1.2% by weight of heat-resistant masterbatch.

[0016] Thus, the present invention can obtain a molding resin composition that satisfies the mechanical and physical properties required by Material Specification No. MS941-07 of the standard specification for the performance and quality of thermoplastic polymer materials for injection molded parts of junction blocks and wiring harnesses among automotive parts.

[0017] In addition, even when molded using molding methods such as injection molding or extrusion molding, it is possible to obtain a molded product with excellent moldability, mechanical strength, and thermal deformability that satisfies the quality conditions of the standard specifications.

[0018] In addition, as a preferred aspect of the present invention, the impact modifier may be applied by grafting 0.5 to 2 weight percent of maleic anhydride onto 100 weight percent of ethylene propylene diene monomer (EPDM).

[0019] In addition, as a preferred aspect of the present invention, the flowability improving agent may be a dendrimer wax that lowers the melt viscosity of the regenerated PA6 and PA66 and improves flowability, thereby improving the processing fluidity of the molded article and increasing the melt index.

[0020] In addition, as a preferred aspect of the present invention, the heat-resistant masterbatch is a polyethylene carbon black masterbatch composed of 30 to 50 weight percent of polyethylene (PE) carrier, 35 to 55 weight percent of carbon black, and the remainder of a light stabilizer, thereby improving fluidity and allowing easy mixing of 35 to 55 weight percent of carbon black and the remainder of the light stabilizer.

[0021] In addition, a preferred aspect of the present invention may have a composition additionally comprising 0.15 to 0.2 weight percent of a heat stabilizer that exhibits a heat-resistant effect resistant to thermal deformation.

[0022] Meanwhile, in a preferred aspect of the present invention, the molding resin composition may have a melt flow index (MFR) of 9.2 to 16.7 g / 10 min measured according to the method specified in ASTM D1238 and a specific gravity of 1.089 to 1.090 g / cm² measured according to the method specified in ISO 1183-1.

[0023] In addition, the above heat-resistant masterbatch may have a melt index of 13.0 to 13.4 g / 10 min as measured according to ASTM D1238 and a specific gravity of 1.0 to 1.2 as measured according to ASTM D792.

[0024] In addition, the molded product manufactured from the above-mentioned molding resin composition has a tensile strength of 46.5–52 MPa and an elongation of 72.4–78% for a specimen measured according to the method specified in ISO 527 (provided that it conforms to ISO 3167, TYPE A, and the test speed is 5 mm / min), a flexural strength of 69–73 MPa and a flexural modulus of 1689–1779 MPa for a specimen measured according to the method specified in ISO 178 (provided that the specimen size is (80 mm × 10 mm × 4 mm), the spacing between supports is 64 mm, and the test speed is 2 mm / min), and a notched Izod impact strength (Notched, 23°C) for a specimen measured according to the method specified in ISO 180, TYPE A (provided that the specimen size is (80 mm × 10 mm × 4 mm) and the notch is 2.54 mm). The heat distortion temperature (HDT) measured under a load (stress) of 0.45 MPa on a specimen (80 mm × 10 mm × 4 mm) according to the method specified in ISO 75 may be 51.7~73 KJ / m² and 172~176°C. Effects of the invention

[0025] According to an embodiment that implements the technical concept on which a unique solution means is based to solve the technical problem of the present invention, a molding resin composition can be obtained that satisfies the mechanical and physical properties specified and required by Material Specification No. MS941-07 for thermoplastic polymer materials and quality performance for injection molded parts of junction blocks and wiring harnesses among automotive parts.

[0026] In addition, when molding is performed using molding methods such as injection molding or extrusion molding, a molded product with excellent moldability, mechanical strength, and thermal deformability that satisfies the quality conditions of the standard specifications can be obtained.

[0027] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Specific details for implementing the invention

[0028] Hereinafter, embodiments according to the present invention will be described in more detail.

[0029] Prior to this, it is specified that the terms described below are defined in consideration of their functions in the present invention, and should be interpreted in accordance with the concept consistent with the technical spirit of the present invention and the meaning commonly accepted or recognized in the relevant technical field.

[0030] In addition, if it is determined that a detailed description of known functions or configurations related to the present invention could obscure the essence of the present invention, such detailed description is omitted.

[0031] In addition, the term "and / or" in this specification means a combination of multiple related described items or includes any of the multiple related described items, and when a part is said to include a certain component, it means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0032] In other words, terms such as "comprising" and "having" as set forth in this specification mean that there is a feature, number, step, process, operation, component, part, or combination thereof, and should be understood as not excluding the existence or addition of one or more other features, numbers, steps, processes, operations, components, parts, or combinations thereof.

[0033] Furthermore, each process and step may occur differently from the specified order unless the context clearly indicates a specific sequence. That is, each process and step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

[0034] [Best mode for carrying out the invention]

[0035] A molding resin composition using recycled plastic according to an embodiment of the present invention comprises 42-45% by weight of PA66 (Polyamide66), which is an aliphatic polyamide resin, 39-41% by weight of recycled PA6 (Recycled Polyamide6), 6-7% by weight of an impact modifier, 3.5-4.5% by weight of linear low-density polyethylene, 3.5-4.5% by weight of low-density polyethylene, 0.35-0.4% by weight of an antioxidant, 0.25-0.3% by weight of a release agent, 0.25-0.3% by weight of a flowability improver, 1-1.2% by weight of a heat-resistant masterbatch, and 0.15-0.2% by weight of a heat-resistant stabilizer.

[0036] PA66 (Polyamide 66) It is one of the engineering thermoplastic resins with excellent strength, stiffness and chemical resistance, which is formed by the condensation polymerization of hexamethylenediamine and adipic acid and has a melting point of 255°C.

[0037] The chemical formula (structural formula) of PA66 is as follows.

[0038]

[0039] PA66 (Polyamide 66) may be included in an amount of 42 to 45 weight percent based on the total weight of the molding resin composition.

[0040] If the content of PA66 (Polyamide 66) in 100 weight% of the molding resin composition is less than 42 weight%, there may be a problem with reduced heat resistance and wear resistance, and if it exceeds 45 weight%, there may be a problem with reduced elongation and impact strength.

[0041] The relative viscosity of PA66 (Polyamide 66) may be in the range of 2.3 to 3.0.

[0042] If the relative viscosity of PA66 (Polyamide 66) is less than 2.3, the tensile strength, impact strength, and heat resistance decrease, and if the relative viscosity exceeds 3.0, there may be a problem with poor extrusion processability due to insufficient fluidity during molding.

[0043] PA66 (Polyamide 66) may be composed of homopolyamide, copolyamide, or a mixture thereof, and may be crystalline, semicrystalline, or amorphous.

[0044] PA66 (Polyamide 66) is a polyamide that does not contain aromatic rings in its molecular chain and may contain aliphatic groups having 10 to 20 carbon atoms.

[0045] PA66 (Polyamide 66) may be a homopolymer, copolymer, terpolymer, or more polymers formed from an aminocarboxylic acid, lactam, or diamine and a dicarboxylic acid.

[0046] Here, copolymer means a polyamide having two or more repeating units of amide and / or diamide molecules.

[0047] The aminocarboxylic acid may be an aminocarboxylic acid having 6 to 12 carbon atoms, and specifically may include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanic acid, or 12-aminododecanoic acid.

[0048] The lactam may be a lactam having 4 to 12 carbon atoms, and specifically may include α-pyrrolidone, ε-caprolactam, ω-laurolactam, or ε-enantholactam.

[0049] The diamine may be an aliphatic or alicyclic diamine, and specifically, the diamine includes tetramethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, aminoethylpiperazine, Bis(p-aminocyclohexyl)methane; 2-methyloctamethylenediamine, trimethylhexamethylenediamine, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane or m-xylylenediamine, etc. may be included.

[0050] The dicarboxylic acid can be an aliphatic or alicyclic dicarboxylic acid.

[0051] Dicarboxylic acids may include adipic acid, 2-methyladipic acid, trimethyladipic acid, glutaric acid, 2,2-dimethylglutaric acid, pimelic acid, souveric acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, malonic acid, dimethylmalonic acid, succinic acid, or 2,2-diethylsuccinic acid.

[0052] Excellent impact strength and processability can be obtained by using PA66 (Polyamide 66), which has a glass transition temperature (Tg) of 35 to 50°C and a melting point of 160 to 210°C.

[0053] Recycled PA6 (Recycled Polyamide 6) It is one of the most widely used polyamides worldwide, with a melting point of 223°C.

[0054] The chemical formula (structural formula) of PA6 is as follows.

[0055]

[0056] These recycled PA6 materials can be obtained primarily from waste fibers, waste fishing nets, etc., after thoroughly removing various impurities.

[0057] Recycled PA6 (Recycled Polyamide 6) may be included in an amount of 39 to 41 weight percent based on the total weight of the molding resin composition.

[0058] If the content of recycled PA6 (Recycled Polyamide 6) in 100 weight% of the molding resin composition is less than 39 weight%, there is a risk that mechanical properties such as heat stability and impact resistance and dimensional stability will be reduced, and if it exceeds 41 weight%, the amount of gas generated during extrusion molding will be high, which may reduce moldability and surface properties.

[0059] Shock reinforcement A molding resin composition with excellent mechanical properties such as impact strength can be obtained by including 6 to 7 weight percent based on the total weight of the molding resin composition.

[0060] If the content of the impact modifier in 100 weight% of the molding resin composition is less than 6 weight%, the impact strength is somewhat improved, but sufficient impact resistance is not achieved, a sharp edge occurs upon breakage due to impact, and sufficient elongation may not be achieved, and if it exceeds 7 weight%, the impact strength is greatly improved, but there may be problems with reduced stiffness such as tensile strength and flexural strength, as well as reduced wear resistance and heat resistance.

[0061] Here, the impact modifier is not particularly limited, but may be a polyester-based elastomer, a butadiene-based elastomer, a styrene-butadiene-styrene copolymer, a styrene-ethylene-butadiene-styrene copolymer, an olefin-based elastomer, a rubber-modified vinyl copolymer, etc., to improve ductility and thus improve impact resistance.

[0062] For example, a rubber-modified vinyl copolymer can be a rubber-modified vinyl graft copolymer.

[0063] A rubber-modified vinyl graft copolymer comprises a monomer mixture of 5% to 95% by weight, consisting of 40% to 95% by weight of styrene, α-methylstyrene, halogen or alkyl-substituted styrene, C1 to C8 alkyl methacrylate esters, C1 to C8 alkyl acrylate esters, or a mixture thereof, and 5% to 60% by weight of acrylonitrile, methacrylonitrile, C1 to C8 alkyl methacrylate esters, C1 to C8 alkyl acrylate esters, maleic anhydride, C1 to C4 alkyl or phenyl N-substituted maleimide, or a mixture thereof, wherein the monomer mixture comprises butadiene rubber, acrylic rubber, ethylene / propylene rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, isoprene rubber, and a terpolymer (EPDM) of ethylene-propylene-diene. It may be a vinyl graft copolymer obtained by graft polymerization on 5% to 95% by weight of one selected from the group consisting of polyorganosiloxane / polyalkyl (meth)acrylate rubber composites or a mixture thereof.

[0064] C1 to C8 alkyl methacrylate esters or C1 to C8 alkyl acrylate esters may each be esters of methacrylic acid or acrylic acid, and may be esters obtained from monohydryl alcohols containing 1 to 8 carbon atoms.

[0065] For example, ethyl lylate ester, ethyl acrylate ester, or propyl methacrylate ester may be used, and among these, methyl methacrylate ester is preferred.

[0066] Preferred examples of rubber-modified vinyl-based graft copolymers include butadiene rubber, acrylic rubber, or styrene / butadiene rubber graft copolymerized with styrene and acrylonitrile and optionally (meth)acrylate alkyl ester monomers in the form of a mixture, and butadiene rubber, acrylic rubber, or styrene / butadiene rubber graft copolymerized with (meth)acrylate methyl ester monomers.

[0067] For example, it may be one or more selected from the group consisting of ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), methyl methacrylate-butadiene-styrene (MBS), styrene-butadiene-styrene (SBS), styrene-ethylene / butylene-styrene copolymer (SEBS), styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPM, EPR), ethylene-propylene-diene copolymer (EPDM), maleic anhydride modified EPM (EPM-g-MA), maleic anhydride modified EPR (EPR-g-MA), maleic anhydride modified SBS (SBS-g-MA), maleic anhydride modified EPDM (EPDM-g-MA), and ethylene vinyl alcohol copolymer (EVOH), among which maleic anhydride modified EPM (EPM-g-MA), maleic anhydride modified EPR (EPR-g-MA), and maleic anhydride modified EPDM (EPDM-g-MA) may be preferred.

[0068] In addition, when manufacturing the graft copolymer, the particle size of the rubber particles is preferably in the range of 0.05㎛ to 4㎛ to improve impact strength and surface properties of the molded product.

[0069] Linear low-density polyethyleneIt may contain 3.5 to 4.5 weight percent based on the total weight of the molding resin composition. By doing so, a molding resin composition with excellent mechanical properties such as friction resistance, scratch resistance, tensile strength, impact strength, stress cracking resistance, flexibility, and impact resistance can be obtained.

[0070] In other words, by adding linear low-density polyethylene, the process of extrusion molding using a molding resin composition is made easy to cut, resulting in good workability and enabling a reduction in production costs, as well as ensuring sufficient low-temperature impact strength.

[0071] 100% by weight of linear low-density polyethylene in a molding resin composition If the content is less than 3.5 weight%, the impact strength of the molded product is poor, and mechanical properties such as flexibility are insufficient, which may result in defects caused by cracking. If it exceeds 4.5 weight%, the impact strength is greatly improved, but stiffness and cushioning properties such as tensile strength and flexural strength are reduced, and problems such as poor workability during injection molding may occur.

[0072] low-density polyethylene It may contain 3.5 to 4.5 weight percent based on the total weight of the molding resin composition. By doing so, a molding resin composition with excellent mechanical properties such as friction resistance, scratch resistance, tensile strength, impact strength, stress cracking, and impact resistance can be obtained.

[0073] That is, when the content of low-density polyethylene is 3.5 to 4.5 weight percent, it has excellent gas barrier properties that block substances causing mold contamination, thereby improving the gas barrier properties of linear low-density polyethylene, as well as excellent processability and heat sealability, which can improve work efficiency in the process of manufacturing molded products using molding methods such as injection molding or extrusion molding.

[0074] If the content of low-density polyethylene in 100% by weight of the molding resin composition is less than 3.5% by weight, the effect of blocking the substance causing mold contamination is negligible, and if it exceeds 4.5% by weight, the effect of blocking the substance causing mold contamination is not significantly improved, and tensile strength and elongation may decrease.

[0075] Here, it is preferable to use low-density polyethylene with a density of 0.910 to 0.925 g / cm³.

[0076] antioxidants It may contain 0.35 to 0.4 weight percent based on the total weight of the molding resin composition. This enables the realization of a molding resin composition and a molded article with excellent mechanical properties such as strength.

[0077] If the content of the antioxidant in 100% by weight of the molding resin composition is less than 0.35% by weight, oxidation due to heat occurs during product molding, and if it exceeds 0.4% by weight, a decrease in mechanical properties such as impact strength may occur and it becomes a factor in increasing costs.

[0078] Here, the type of antioxidant is not limited as long as it inhibits or blocks the chemical reaction between the thermoplastic resin composition and oxygen to prevent the loss or deterioration of intrinsic properties due to decomposition, and for example, antioxidants such as amine-based, phenol-based, thioester-based, and phosphite-based agents may be used.

[0079] This type of mold It may contain 0.25 to 0.3 weight percent based on the total weight of the molding resin composition. This eliminates the adhesion between the molded product and the mold during the molding process, thereby preventing damage to the mold and allowing the molded product to be separated from the mold quickly and easily.

[0080] If the content of the release agent in 100% by weight of the molding resin composition is less than 0.25% by weight, the separation effect is reduced, and if it exceeds 0.3% by weight, mechanical properties such as impact strength may deteriorate and become a factor in increasing costs.

[0081] Here, the release agent is not particularly limited, but one or more selected from the group consisting of aliphatic carboxylic acids, aliphatic carboxylic acid esters, aliphatic polyethers, non-oxidizing polyolefins, and oxidizing polyolefins having carboxyl groups may be used.

[0082] Flow improver It may contain 0.25 to 0.3 weight percent based on the total weight of the molding resin composition. This prevents adhesion between the extruder or mold surface and the resin composition, lowers melt viscosity to improve moldability, and improves product quality by reducing deterioration during processing, such as lowering processing temperature and shortening processing time.

[0083] If the content of the flowability improver in 100% by weight of the molding resin composition is less than 0.25% by weight, the improvement in flowability is negligible and processability is reduced, and if it exceeds 0.3% by weight, flowability is good and processing is easy, but the strength may be weak.

[0084] Here, as a flowability improver, dendrimer wax is preferred to lubricate the metal surface in contact with the thermoplastic resin composition during processing, molding, or extrusion to help the flow or movement of the resin composition. In addition, Montan wax, esterified montan wax, olefin-based and amide-based waxes, EBS (Ethylene Bis-straraminide) wax, etc., may be used.

[0085] Heat-resistant masterbatch (Master batch) may contain 1 to 1.2 weight percent based on the total weight of the molding resin composition. This enables the realization of a molding resin composition and a molded article with excellent heat distortion temperature characteristics.

[0086] If the content of the heat-resistant masterbatch in 100% by weight of the molding resin composition is less than 1% by weight, the heat deformation temperature characteristics are negligible, and if it exceeds 1.2% by weight, a decrease in mechanical properties such as impact strength may occur and it becomes a factor in increasing costs.

[0087] Specifically, the heat-resistant masterbatch can be made more fluid and the carbon black and the remaining amount of light stabilizer can be easily mixed by applying a polyethylene carbon black masterbatch composed of 30 to 50 weight percent of polyethylene (PE) carrier, 35 to 55 weight percent of carbon black, and the remainder of a light stabilizer.

[0088] In this case, if the light stabilizer is added in a small amount, improvement in lightfastness cannot be expected, and if it is added in excess, there is a risk of problems with processability and the color of the molded product.

[0089] Here, it is preferable to use N,N-Bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine polymer with 2,4-dichloro-6-(4-morpholinyl)-1,3,5-triazine as a light stabilizer, which inhibits or blocks the decomposition of the thermoplastic resin composition from ultraviolet rays, causing discoloration or loss of mechanical properties.

[0090] In addition, benzotriazole-based UV stabilizers including 2-hydroxyphenylbenzotriazole, benzophenone-based UV stabilizers including 2-hydroxybenzophenone, benzoate-based UV stabilizers including benzoate, and cyanoacrylate-based UV stabilizers including cyanoacrylate may be used.

[0091] Heat stabilizerIt may additionally include 0.15 to 0.2 weight percent based on the total weight of the molding resin composition. This allows for the stable realization of a heat resistance effect that is strong against thermal deformation.

[0092] Here, the heat stabilizer comprises 30% by weight of modified polyphenyloxide, 30% by weight of modified polybenzimidazole resin, 10% by weight of polyvinylsilsesquioxane, 10% by weight of polybutylene terephthalate, 10% by weight of polycyclohexylenedimethylene terephthalate, 5% by weight of hydroxyethyl acrylate, and 5% by weight of polyesterimide polyol, thereby effectively suppressing thermal decomposition of the thermoplastic resin composition when kneaded or molded at high temperatures.

[0093] Additionally, the modified polyphenyloxide may comprise 80% by weight of polyphenylene oxide and 20% by weight of maleic anhydride-grafted ethylene-propylene-diene (Mg-g-EPDM), and the modified polybenzimidazole resin may comprise 80% by weight of polybenzimidazole resin and 20% by weight of polyurethane / elastomer block copolymers (TPUS).

[0094] The method for manufacturing a molding resin composition using recycled plastic according to an embodiment of the present invention configured as described above is not particularly limited and can be appropriately selected depending on the equipment used and other process elements.

[0095] For example, plastic pellets can be manufactured by introducing each component into a barrel, melting and mixing at 200–350°C at 180–400 rpm, extruding with temperature conditions of a single screw or twin screw extruder set to 195–250°C for the rear, 210–355°C for the middle, 210–380°C for the front, 210–380°C for the head, and 210–400°C for the die, and then using a pelletizer to form polymer pellets with a size of about 2–5 mm, followed by drying at 80–120°C for 2–4 hours.

[0096] In addition, using plastic pellets obtained from a molding resin composition using recycled plastic according to an embodiment of the present invention, molded products having excellent appearance characteristics, mechanical properties, and dimensional stability can be manufactured through various molding methods such as injection molding, extrusion molding, and casting molding.

[0097] [Methods for Evaluating Physical Properties]

[0098] After mixing the contents of each component forming the molding resin composition using recycled plastic according to the embodiment of the present invention differently as in Examples 1 to 3 and Comparative Examples 1 to 4 listed in Table 1 below, the melt flow index (MFR) of the sample was measured according to ASTM D1238 and the specific gravity of the sample was measured according to ISO 1183-1.

[0099] Here, the Melt Index (MFR) is an indicator that measures the flowability of plastic resins. It evaluates the processability and physical properties of plastic materials by measuring the amount of plastic material that melts and flows at a certain temperature and pressure. A lower Melt Index value indicates higher viscosity of the material, which may result in a strong but difficult-to-process molded product. Conversely, a higher Melt Index value indicates that the plastic material flows more easily and is easier to process, but the strength of the molded product may be weak.

[0100] Meanwhile, each resin composition according to Examples 1 to 3 and Comparative Examples 1 to 4 was fed into an extruder, and after compounding, kneaded at a melting temperature of 184°C and extruded at a die temperature of 250°C to produce pellets. At this time, a twin screw extruder with L / D=36 and a diameter of 45 mm was used for extrusion. The produced pellets were dried at 80–100°C for at least 4 hours, and then injection molded in a 6 OZ injection molding machine (molding temperature 280°C, mold temperature 60°C) to produce specimens. The physical properties of each produced specimen were evaluated by the following method, and the results are shown in Table 2 below.

[0101] Here, each specimen was used after 48 hours had elapsed since manufacturing and had been left for at least 24 hours in a test room maintained under standard conditions of a temperature of 23±2℃ and a relative humidity of 50±5%. Each test item was evaluated using 7 specimens, and the result was expressed as the arithmetic mean of the remaining 5 values, excluding the 2 upper and lower limit values.

[0102] 1) Tensile strength and elongation: The tensile strength and elongation of the specimens were measured according to the evaluation method specified in ISO 527 (provided that ISO 3167, TYPE A is followed and the test speed is 5 mm / min).

[0103] 2) Flexural strength and flexural modulus: The flexural strength and flexural modulus of the specimen were measured according to the evaluation method specified in ISO 178 (wherein the specimen size is (80mm × 10mm × 4mm), the spacing between supports is 64mm, and the test speed is 2mm / min).

[0104] 3) Notched Izod impact strength (Notched, 23℃): According to the evaluation method specified in ISO 180 TYPE A, a notch was made in the specimen (wherein the specimen size is (80mm × 10mm × 4mm) and the notch is 2.54mm) and the notched Izod impact strength (Notched, 23℃) was evaluated.

[0105] 4) Heat distortion temperature (°C): According to the evaluation method specified in ISO 75, the heat distortion temperature (HDT) of a specimen (80 mm × 10 mm × 4 mm) was measured under a load (stress) of 0.45 MPa.

[0106] Example 1 Example 2 Example 3 Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 PA66 42 wt% 43 wt% 45 wt% 43 wt% 43 wt% 43 wt% 43 wt% Playback PA6 41 wt% 40 wt% 39 wt% 40 wt% 40 wt% 40 wt% 40 wt% Shock reinforcement 6 wt% 7 wt% 6 wt% 8 wt% 7 wt% 7 wt% 7 wt% LLDPE 4.5 wt% 4.0 wt% 3.5 wt% 4.0 wt% 4.0 wt% 4.0 wt% 4.0 wt% LDPE 4.2 wt% 3.7 wt% 4.3 wt% 4.0 wt% 4.0 wt% 4.0 wt% 4.0 wt% antioxidants 0.40 wt% 0.34 wt% 0.35 wt% 0.40 wt% 0.40 wt% 0.40 wt% 0.40 wt% This type of mold 0.30 wt% 0.30 wt% 0.25 wt% 0.30 wt% 0.30 wt% 0.30 wt% 0.30 wt% Flow improver 0.3 wt% 0.28 wt% 0.3 wt% - 0.60 wt% 0.25 wt% 0.25 wt% Heat-resistant masterbatch 1.1 wt% 1.2 wt% 1.1 wt% 1.0 wt% 3.0 wt% 1.0 wt% - Heat stabilizer 0.2 wt% 0.18 wt% 0.2 wt% - - - -

[0107] Evaluation items MI(g / 10min) Specific gravity (g / cm²) Tensile strength (MPa) Growth Rate (%) Flexural strength (MPa) Flexural modulus (MPa) Izod impact strength (KJ / ㎡) Heat distortion temperature (HDT) Standard specifications 6~16 1.09±0.03 43↑ 70↑ 68↑ 1,655↑ 45↑ 170↑ Example 1 13.2 1.089 46.5 78 73 1,747 51.7 172 Example 2 16.7 1.090 52 72.4 71.3 1,779 60.2 176 Example 3 9.2 1.089 49 75 69 1,689 72.9 174 Comparison Example 1 4.2 1.081 50 55 71.4 1,732 73 174 Comparison Example 2 9.6 1.089 49 54 68.1 1,689 72.9 174 Comparison Example 3 4.8 1.085 43.6 60 59 1,390 61 85 Comparison Example 4 9.4 1.085 45.6 75 69 1,708 63.9 86

[0108] As shown in Table 2, it can be confirmed that the sample of the molding resin composition using recycled plastic according to the embodiment of the present invention has a melt flow index (MFR) of 9.2 to 16.7 g / 10 min measured according to the method specified in ASTM D1238 and a specific gravity of 1.089 to 1.090 g / cm² measured according to the method specified in ISO 1183-1.

[0109] In addition, the molded article manufactured from the molding resin composition using recycled plastic according to the embodiment of the present invention has a tensile strength of 46.5~52 MPa and an elongation of 72.4~78% for a specimen measured according to the method specified in ISO 527 (provided that it follows ISO 3167, TYPE A, and the test speed is 5 mm / min), a flexural strength of 69~73 MPa and a flexural modulus of 1689~1779 MPa for a specimen measured according to the method specified in ISO 178 (provided that the specimen size is (80 mm × 10 mm × 4 mm), the spacing between supports is 64 mm, and the test speed is 2 mm / min), and a notched Izod impact strength (Notched, 23°C) for a specimen measured according to the method specified in ISO 180, TYPE A (provided that the specimen size is (80 mm × 10 mm × 4 mm) and the notch is 2 mm). It can be confirmed that the heat distortion temperature (HDT) measured under a load (stress) of 0.45 MPa on a specimen (80 mm × 10 mm × 4 mm) according to the method specified in ISO 75 is 51.7~73 KJ / ㎡ and is 172~176℃.

[0110] That is, the molded article manufactured from the molding resin composition using recycled plastic according to the embodiment of the present invention exhibited excellent physical properties, including mechanical and physical properties such as impact resistance and elongation, as well as moldability, mechanical strength, and thermal deformability.

[0111] On the other hand, Comparative Example 1, which did not contain a flowability improver and a heat-resistant masterbatch, had a very low melt flow index (MFR) and specific gravity compared to Examples 1 and 2, and Comparative Example 2, which exceeded the appropriate content of a flowability improver and a heat-resistant masterbatch, mostly satisfied the quality criteria of the standard specification but had a significantly lower elongation.

[0112] In addition, Comparative Example 3, which fell short of the appropriate content of flow improver and heat-resistant masterbatch, satisfied the quality criteria of the standard specification for tensile strength and impact strength, but the rest were significantly lower than Examples 1 to 3.

[0113] In addition, Comparative Example 4, which did not contain a heat-resistant masterbatch, had improved elongation but significantly lower specific gravity and heat distortion temperature.

[0114] Accordingly, it can be seen that a molding resin composition comprising PA66 (Polyamide 66), an aliphatic polyamide resin, recycled PA6 (Recycled Polyamide 6), an impact modifier, linear low-density polyethylene, low-density polyethylene, an antioxidant, a release agent, a flowability improver, and a heat-resistant masterbatch in an optimal mixing ratio according to an embodiment of the present invention satisfies the mechanical and physical properties required by the Material Specification for the performance and quality of thermoplastic polymer materials for injection molded parts.

[0115] Furthermore, it can be seen that even when molded using molding methods such as injection molding or extrusion molding, molded products with excellent processability, mechanical strength, and thermal deformability that satisfy the quality conditions of the standard specifications can be obtained.

[0116] Meanwhile, it is obvious to those skilled in the art that the present invention is not limited by the embodiments described above and the attached drawings, and that it can be modified and applied in various ways not exemplified within the scope of the technical concept of the present invention, as well as widely applied by substituting each component and changing to equivalent alternative embodiments.

[0117] Therefore, content related to modifying and applying the technical features of the present invention should be interpreted as being included within the technical concept and scope of the present invention.

Claims

Claim 1 42~45 wt% of aliphatic polyamide resin PA66 (Polyamide 66); 39~41 wt% of recycled PA6 (Recycled Polyamide 6); 6~7 wt% of impact modifier; 3.5~4.5 wt% of linear low-density polyethylene; 3.5~4.5 wt% of low-density polyethylene; 0.35~0.4 wt% of antioxidant; 0.25~0.3 wt% of release agent; 0.25~0.3 wt% of flow improver; 1~1.2 wt% of heat-resistant masterbatch; It comprises 0.15 to 0.2 wt% of a heat stabilizer; wherein the impact modifier is obtained by grafting 0.5 to 2 wt% of maleic anhydride onto 100 wt% of ethylene propylene diene monomer (EPDM); the flowability improver is a dendrimer wax that lowers the melt viscosity of the regenerated PA6 and PA66 and improves flowability to improve the processing fluidity of the molded article and increase the melt index; the heat-resistant masterbatch is a polyethylene carbon black masterbatch composed of 30 to 50 wt% of polyethylene (PE) carrier, 35 to 55 wt% of carbon black, and the remainder being a light stabilizer; and the heat stabilizer comprises 30 wt% of modified polyphenyl oxide, 30 wt% of modified polybenzimidazole resin, and 10 wt% of polyvinylsilsesquioxane. A molding resin composition using recycled plastic, characterized by comprising 10% by weight of polybutylene terephthalate, 10% by weight of polycyclohexylenedimethylene terephthalate, 5% by weight of hydroxyethyl acrylate, and 5% by weight of polyesterimide polyol. Claim 2 delete Claim 3 In claim 1, the molding resin composition has a melt flow index (MFR) of 9.2–16.7 g / 10 min as measured according to the method specified in ASTM D1238, and a specific gravity of 1.089–1.090 g / cm² as measured according to the method specified in ISO 1183-1; and the molded article produced from the molding resin composition has a tensile strength of 46.5–52 MPa and an elongation of 72.4–78% as measured by a specimen (provided it conforms to ISO 3167, TYPE A, and the test speed is 5 mm / min) as measured according to the method specified in ISO 527, and a flexural strength of 69–73 MPa and a flexural modulus as measured by a specimen (provided the specimen size is (80 mm × 10 mm × 4 mm), the spacing between supports is 64 mm, and the test speed is 2 mm / min) as measured according to the method specified in ISO 178. A molding resin composition using recycled plastic, having a notched Izod impact strength (Notched, 23℃) of 51.7~73KJ / ㎡ of a specimen (80mm×10mm×4mm, notch 2.54mm) measured according to the method specified in ISO 180 TYPE A, and a heat distortion temperature (HDT) of 172~176℃ of a specimen (80mm×10mm×4mm) measured under a load (stress) of 0.45MPa according to the method specified in ISO 75.

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