Regenerated resin composition

Abstract

The present invention relates to a recycled resin composition, which comprises a base resin including a graft resin and a heat-resistant resin, and a recycled graft resin, wherein the heat-resistant resin is one or more copolymers selected from the group consisting of alkyl-substituted aromatic vinyl copolymers and aromatic vinyl-imide copolymers, and the recycled graft resin has a heat distortion temperature of 82°C to 90°C and a tensile strength of 41 MPa to 54 MPa, making it possible to provide an environmentally friendly recycled resin that does not suffer from deterioration in thermal and mechanical properties.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0167407, filed December 5, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a recycled resin composition that is environmentally friendly and does not suffer from deterioration in physical properties. [Background technology]

[0003] With the rapid development of advanced materials and equipment, many new technologies are being developed and various technological facilities are continuously being developed. As a result, consumption of electrical and electronic equipment is increasing, and at the same time, the amount of waste electrical and electronic equipment is also increasing. Plastics are widely used in electrical and electronic equipment because they are low-hazard and inexpensive, but their low compressibility and high elasticity make them difficult to recycle, occupying a large volume during the recycling process.

[0004] Meanwhile, with growing concern about the environment worldwide, regulations to curb carbon dioxide emissions are being strengthened. In particular, environmental pollution caused by the recent increase in plastic use has become a serious issue, and an increasing number of countries are introducing producer responsibility recycling systems for plastics as part of the global circular economy trend. The United States, in particular, is tightening regulations at the manufacturing stage, such as mandating the use of recycled resins, and there is also a trend toward introducing plastic taxes and border carbon taxes. Various efforts are being made to introduce waste plastic recycling laws and biomaterials. Therefore, manufacturers are required to add a specified amount of recycled resin when producing plastic molded products, and eco-friendly grades are assigned based on the amount of recycled resin.

[0005] However, because recycled resin is a processed resin, it contains additives such as colorants, lubricants, and release agents, and its properties have already changed due to high-temperature processing. As the recycled resin content increases, the physical properties inevitably deteriorate compared to conventional resins. In particular, it does not have sufficient chemical resistance to organic solvents, detergents, or fragrances used in post-processing of resin molded products, and there are problems such as cracks or breakage, making it difficult to commercialize.

[0006] Therefore, there is a need to develop technology that uses recycled resins, is environmentally friendly, and when applied to actual industries, minimizes the deterioration of thermal and mechanical properties compared to using new conventional plastics, making it possible to practically commercialize the product. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent Publication No. 10-2016-0144185 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to provide a recycled resin composition that uses recycled resin recycled from used resin, is environmentally friendly, minimizes deterioration in thermal properties such as heat resistance and mechanical properties such as tensile strength and impact strength, has excellent paintability, and can be used in place of virgin resin. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a recycled resin composition comprising a base resin containing a graft resin and a heat-resistant resin, and a recycled graft resin, wherein the heat-resistant resin is one or more copolymers selected from the group consisting of alkyl-substituted aromatic vinyl copolymers and aromatic vinyl-imide copolymers, and the recycled graft resin has a heat distortion temperature of 82°C to 90°C and a tensile strength of 41 MPa to 54 MPa.

[0010] The present invention also provides a molded article containing the recycled resin composition. [Effects of the Invention]

[0011] The recycled resin composition according to the present invention can ensure environmental friendliness by using recycled resin recycled from used resin. By using recycled resin, the amount of virgin resin added is relatively small, but deterioration of thermal and mechanical properties is minimized and excellent paintability can be achieved, and it has the advantage of being able to fully replace virgin resin. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will now be described in more detail to aid in understanding the present invention.

[0013] The terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as having meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that inventors can appropriately define the concepts of terms in order to best explain their inventions.

[0014] The terms and measurement methods used in the present invention can be defined as follows, unless otherwise defined.

[0015] As used herein, the term "composition" includes mixtures of materials comprising the composition as well as reaction products and decomposition products formed from the materials of the composition.

[0016] The term "monomer unit" or "monomer-derived unit" used in the present invention may refer to a repeating unit formed when a compound used as a monomer participates in a polymerization reaction, a structure resulting therefrom, or the substance itself.

[0017] The term "derivative" as used in the present invention can refer to a compound in which one or more hydrogen atoms constituting the original compound are substituted with a halogen group, an alkyl group or a hydroxy group.

[0018] In the present invention, the "polymerization conversion rate" indicates the degree to which a monomer is polymerized to form a polymer through a polymerization reaction. A portion of the polymer in a reactor is sampled during polymerization, and the weight of the polymer excluding water is calculated according to the following mathematical formula 1. The sample is then dissolved in tetrahydrofuran (THF) solvent and precipitated in methanol (MeOH). Unreacted monomers are removed, and the precipitate is dried and the weight of the obtained polymer is measured and calculated according to the following mathematical formula 2.

[0019] [Mathematical formula 1] (Actual weight of polymer) = (collected polymer) - (collected polymer × water content)

[0020] [Mathematical formula 2] Polymerization conversion rate (%) = [(weight of polymer obtained after drying) / (weight of actual polymer)] × 100

[0021] recycled resin composition The recycled resin composition according to the present invention comprises a base resin containing a graft resin and a heat-resistant resin, and a recycled graft resin, wherein the heat-resistant resin is one or more copolymers selected from the group consisting of alkyl-substituted aromatic vinyl copolymers and aromatic vinyl-imide copolymers, and the recycled graft resin has a heat distortion temperature of 82°C to 90°C and a tensile strength of 41 MPa to 54 MPa.

[0022] Generally, when two or more resins are blended to manufacture a molded product, at least one of the mixed resins acts as a matrix (continuous phase), and the remaining resins act as a filler (dispersed phase). However, when a recycled graft resin acting as a filler, as in the present invention, is used to replace the virgin graft resin, the desired physical properties cannot be achieved, and the reduced physical properties cannot be compensated for by techniques such as the addition of another resin or additives. Therefore, when using a recycled graft resin, a method is used in which the recycled graft resin is added in place of the resin acting as the matrix. However, the resin acting as the matrix also has the same problems. Therefore, when using a recycled graft resin, a method is needed to minimize the degradation of processability and final physical properties, and the present invention provides a solution to this problem.

[0023] According to one embodiment of the present invention, the recycled resin composition is environmentally friendly and can address environmental issues related to plastics by using recycled graft resin recycled from used resin. It has the advantage of not causing a decrease in thermal and mechanical properties that can occur when the amount of virgin resin used is reduced by using recycled resin, and it has excellent paintability and can fully replace virgin resin in the same field.

[0024] In addition, in order to prevent deterioration of both thermal and mechanical properties and ensure paintability, the recycled graft resin is used as a base resin along with a graft resin and a heat-resistant resin, and this combination can more effectively demonstrate the above-mentioned advantages.

[0025] Regenerated graft resin According to one embodiment of the present invention, the recycled resin composition includes a recycled graft resin. The recycled graft resin is selected to have physical properties such as a heat distortion temperature of 82°C to 90°C and a tensile strength of 41 MPa to 54 MPa. The recycled graft resin can be formed by a separate recycling process after a plastic product using an acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as "ABS resin") as the graft resin is discarded.

[0026] Therefore, the recycled graft resin may contain a conjugated diene polymer, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit. The description of the monomer units is the same as that of the graft resin, and will be described later in the description of the graft resin.

[0027] According to one embodiment of the present invention, the recycled graft resin must satisfy certain physical properties, one of which is a thermal property, that is, a heat distortion temperature of 82°C to 90°C, preferably 83°C to 88°C, more preferably 84°C to 87°C, and most preferably 84°C to 86°C. If a recycled graft resin with a heat distortion temperature lower than 82°C is used, the heat resistance of the molded article may not be ensured and the mechanical properties may be reduced. If a recycled graft resin with a heat distortion temperature higher than 90°C is used, the paintability of the molded article may not be uniform or erosion may occur.

[0028] According to one embodiment of the present invention, the recycled graft resin must have a tensile strength in the range of 41 MPa to 54 MPa, preferably 43 MPa to 50 MPa, more preferably 44 MPa to 48 MPa, and most preferably 45 MPa to 47 MPa. The recycled graft resin of the present invention preferably satisfies this range; if the recycled graft resin has a tensile strength greater than 54 MPa, it may not disperse well in the matrix resin, resulting in uneven coating or erosion. Furthermore, using a recycled graft resin with a tensile strength lower than 41 MPa carries the risk of the molded article itself being inferior in tensile strength. Therefore, it is preferable to use a recycled graft resin with a tensile strength in the above range.

[0029] On the other hand, the tensile strength of ABS resin tends not to be significantly lower than that of virgin resin, even when recycled from virgin ABS resin. Therefore, it is preferable to use recycled graft resins with an appropriate level of tensile strength, and it is generally recognized that the higher the tensile strength, the better. However, in the present invention, it may be more appropriate for the tensile strength of the recycled graft resin to satisfy the above range rather than simply being high in order to achieve the effects of the present invention.

[0030] Furthermore, according to one embodiment of the present invention, it is preferable that the recycled graft resin further satisfy the Izod impact strength of 8 kgf·cm / cm to 25 kgf·cm / cm. The Izod impact strength is more preferably 9 kgf·cm / cm to 20 kgf·cm / cm, and even more preferably 9 kgf·cm / cm to 18 kgf·cm / cm. As with the tensile strength, it is preferable for the impact strength to have an appropriate level rather than being merely high in order to achieve the effects of the present invention.

[0031] According to one embodiment of the present invention, the recycled resin composition may contain 50 to 90 parts by weight of the base resin and 10 to 50 parts by weight of the recycled graft resin, based on 100 parts by weight. Preferably, the recycled resin composition may contain 60 to 85 parts by weight of the base resin and 15 to 40 parts by weight of the recycled graft resin. Adding 10 parts by weight or more of the recycled graft resin is the minimum requirement for achieving environmental friendliness and achieving a uniform, erosion-free coating surface on molded articles. Adding 50 parts by weight or less may ensure excellent uniformity of physical properties and the minimum amount of virgin resin that must be added to ensure minimum physical properties for commercialization.

[0032] Base resin 1: Graft resin According to one embodiment of the present invention, the recycled resin composition includes a base resin, which includes a graft resin. The graft resin may be included in an amount of 5 to 50 parts by weight, 10 to 40 parts by weight, or 15 to 35 parts by weight, based on 100 parts by weight of the recycled resin composition. Within this range, excellent impact strength and tensile strength can be ensured, and paintability can also be improved.

[0033] The graft resin may contain a conjugated diene polymer, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit. As described above, the graft resin may be an acrylonitrile-butadiene-styrene copolymer, which provides the recycled resin composition with excellent moldability and impact resistance. The graft resin may be a graft copolymer with a core-shell structure including a core containing a conjugated diene monomer unit and a shell surrounding the core and containing an aromatic vinyl monomer unit and a vinyl cyanide monomer unit.

[0034] According to an embodiment of the present invention, the acrylonitrile-butadiene-styrene copolymer may be prepared by emulsion polymerization and emulsion graft polymerization. For example, the acrylonitrile-butadiene-styrene copolymer may be prepared by emulsion polymerizing a conjugated diene monomer to prepare a core (or seed) which is a rubber polymer, and then adding a vinyl cyanide monomer and an aromatic vinyl monomer to the core and emulsion graft polymerizing the resulting mixture.

[0035] In addition, the acrylonitrile-butadiene-styrene copolymer may include 30 wt% to 70 wt% of a core including units derived from a conjugated diene monomer; and 30 wt% to 70 wt% of a shell surrounding the core and including units derived from an aromatic vinyl monomer and units derived from a vinyl cyanide monomer. Here, the shell may include the units derived from the aromatic vinyl monomer and the units derived from the vinyl cyanide monomer in a weight ratio of 7:3 to 8:2. In this case, the copolymer may have better impact resistance, mechanical properties, and moldability.

[0036] According to one embodiment of the present invention, the conjugated diene monomer of the acrylonitrile-butadiene-styrene copolymer may be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and isoprene, and a specific example thereof may be 1,3-butadiene.

[0037] According to one embodiment of the present invention, the aromatic vinyl monomer may be at least one selected from the group consisting of styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, o-methylstyrene, ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, and derivatives thereof, and a specific example thereof may be styrene.

[0038] The aromatic vinyl monomer may be added in an amount of 30 to 95 parts by weight, 40 to 90 parts by weight, 50 to 85 parts by weight, or 60 to 80 parts by weight, relative to 100 parts by weight of the aromatic vinyl monomer and vinyl cyanide monomer constituting the shell. Within this range, a copolymer can be obtained with a high polymerization conversion rate, the mechanical properties of the copolymer can be maintained, and the copolymer has excellent compatibility with thermoplastic resins.

[0039] According to one embodiment of the present invention, the vinyl cyanide-based monomer may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and derivatives thereof, and a specific example thereof may be acrylonitrile.

[0040] According to one embodiment of the present invention, the vinyl cyanide monomer may be added in an amount of 5 to 70 parts by weight, 10 to 60 parts by weight, 15 to 50 parts by weight, or 20 to 40 parts by weight, based on 100 parts by weight of the aromatic vinyl monomer and vinyl cyanide monomer constituting the shell. Within this range, a copolymer can be obtained with a high polymerization conversion rate, the mechanical properties of the copolymer can be maintained, and the copolymer has excellent compatibility with thermoplastic resins.

[0041] According to one embodiment of the present invention, the conjugated diene monomer of the unsaturated ester graft copolymer may be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and isoprene, and a specific example thereof may be 1,3-butadiene.

[0042] Meanwhile, a graft resin according to an embodiment of the present invention may be obtained by copolymerizing an unsaturated ester-based monomer with the shell. The unsaturated ester-based monomer may be an alkyl(meth)acrylate-based monomer, and the alkyl(meth)acrylate-based monomer may be at least one selected from the group consisting of methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, decyl(meth)acrylate, and lauryl(meth)acrylate. Specifically, the alkyl(meth)acrylate monomer may be at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate.

[0043] When the unsaturated ester-based monomer is further included as a constituent monomer of the shell and subjected to emulsion graft polymerization, the content thereof can be appropriately adjusted. The unsaturated ester-based monomer can be included as a main component or as an additional component, which can be appropriately selected depending on the desired physical properties.

[0044] The graft resin may be a commercially available resin and may be obtained by a commercially available method, but is not particularly limited thereto. In addition, the recycled graft resin has the same components as a virgin graft resin, but may be produced by a predetermined recycling process after discarding the virgin graft resin.

[0045] Base resin 2: Heat-resistant resin According to one embodiment of the present invention, the recycled resin composition includes a base resin, which includes a heat-resistant resin. The heat-resistant resin may be included in an amount of 10 to 70 parts by weight, 20 to 60 parts by weight, or 25 to 55 parts by weight, based on 100 parts by weight of the recycled resin composition. Within these ranges, degradation of impact strength and tensile strength can be minimized, heat resistance can be ensured, and paintability can be improved. The heat-resistant resin may be a copolymer selected from the group consisting of alkyl-substituted aromatic vinyl copolymers and aromatic vinyl-imide copolymers, used alone, or two copolymers may be used together.

[0046] The two copolymers used as the heat-resistant resins are essential components that ensure heat resistance in the recycled resin composition. In particular, alkyl-substituted aromatic vinyl copolymers can balance heat resistance with thermal and mechanical properties, such as tensile and impact strength, while aromatic vinyl-imide copolymers are particularly advantageous in ensuring thermal properties. When both copolymers applicable as the heat-resistant resins are used, the weight ratio of alkyl-substituted aromatic vinyl copolymer to aromatic vinyl-imide copolymer may be 90:10 to 10:90, 90:10 to 30:70, 90:10 to 40:60, or 90:10 to 50:50.

[0047] 1) Alkyl-substituted aromatic vinyl copolymer According to one embodiment of the present invention, the alkyl-substituted aromatic vinyl copolymer may include an alkyl-substituted aromatic vinyl monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit.

[0048] According to one embodiment of the present invention, the alkyl-substituted aromatic vinyl monomer may be at least one selected from the group consisting of α-methylstyrene, α-ethylstyrene, p-methylstyrene, o-methylstyrene, ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, and derivatives thereof, and a specific example thereof may be α-methylstyrene.

[0049] The alkyl-substituted aromatic vinyl monomer may be added in an amount of 30 to 95 parts by weight, 40 to 90 parts by weight, 50 to 85 parts by weight, or 60 to 80 parts by weight, based on 100 parts by weight of the total monomers added. Within this range, a copolymer can be obtained with a high polymerization conversion rate, and the mechanical properties of the copolymer can be maintained while ensuring thermal properties, thereby providing an excellent effect of maintaining a balance between the physical properties.

[0050] According to an embodiment of the present invention, the aromatic vinyl monomer and the vinyl cyanide monomer are the same as those described in the graft resin, and therefore, the description thereof will be omitted.

[0051] The aromatic vinyl monomer may be added in an amount of 1 to 20 parts by weight, 2 to 15 parts by weight, or 5 to 15 parts by weight based on 100 parts by weight of the total amount of monomers. The amount may be relatively small because it is different from the alkyl-substituted aromatic vinyl monomer and is a similar monomer.

[0052] According to one embodiment of the present invention, the vinyl cyanide monomer may be added in an amount of 5 to 70 parts by weight, 10 to 60 parts by weight, 15 to 50 parts by weight, or 20 to 40 parts by weight, based on 100 parts by weight of the total monomers. Within this range, a copolymer can be obtained with a high polymerization conversion rate, and the copolymer can maintain its mechanical properties while exhibiting excellent thermal properties, effectively maintaining a balance between the physical properties.

[0053] The copolymer may have a weight-average molecular weight of, for example, 40,000 g / mol to 200,000 g / mol, preferably 50,000 g / mol to 150,000 g / mol, and more preferably 70,000 g / mol to 130,000 g / mol. Within this range, excellent chemical resistance, processability, and a good balance of physical properties are achieved. The copolymer can be produced by methods such as emulsion polymerization, suspension polymerization, bulk polymerization, and continuous bulk polymerization, and it is particularly preferable to use one produced by continuous bulk polymerization.

[0054] The alkyl-substituted aromatic vinyl copolymer may be a commercially available copolymer and may be obtained by a commercially available method, but is not particularly limited thereto.

[0055] 2) Aromatic vinyl-imide copolymer According to one embodiment of the present invention, the aromatic vinyl-imide copolymer may include an aromatic vinyl monomer unit, an imide monomer unit, and an unsaturated acid anhydride monomer unit.

[0056] The aromatic vinyl monomer is as described above, and therefore the description thereof will be omitted.

[0057] According to an embodiment of the present invention, the imide-based monomer may be a maleimide-based monomer, specifically a maleimide-based monomer in which a hydrogen atom bonded to a maleimide atom is substituted with a substituent. More specifically, the imide-based monomer may be at least one selected from the group consisting of N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, Nt-butylmaleimide, N-cyclohexylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-bromophenylmaleimide, N-laurylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, N-phenylmaleimide, 2-methyl-N-phenylmaleimide, N-benzylmaleimide, N-naphthylmaleimide, and derivatives thereof, specifically N-phenylmaleimide.

[0058] According to one embodiment of the present invention, the imide monomer may be added in an amount of 30 to 95 parts by weight, 40 to 90 parts by weight, 50 to 85 parts by weight, or 60 to 80 parts by weight based on the total amount of added monomers. Within this range, a copolymer can be obtained with a high polymerization conversion rate, a copolymer having a uniform composition of monomer units can be produced, and the produced copolymer has excellent heat resistance.

[0059] According to one embodiment of the present invention, the unsaturated acid anhydride monomer may be, for example, at least one selected from the group consisting of maleic anhydride, itaconic anhydride, citraconic anhydride, and aconitic anhydride, and specifically, may be maleic anhydride.

[0060] According to one embodiment of the present invention, the unsaturated acid anhydride monomer may be added in an amount of 1 to 50 parts by weight, 5 to 40 parts by weight, or 5 to 30 parts by weight. Within this range, a copolymer can be obtained with a high polymerization conversion rate, a copolymer having a uniform composition of monomer units can be produced, and the produced copolymer has excellent heat resistance.

[0061] Known methods can be used to produce aromatic vinyl-imide copolymers. For example, there is a method of copolymerizing a monomer mixture containing an aromatic vinyl monomer, an imide monomer, an unsaturated acid anhydride monomer, and other copolymerizable monomers. Another method involves copolymerizing a monomer mixture containing an aromatic vinyl monomer, an unsaturated acid anhydride monomer, and other copolymerizable monomers, and then reacting ammonia or a primary amine to imidize some of the unsaturated acid anhydride monomer units and convert them into imide monomer units (hereinafter referred to as the "post-imidization method").

[0062] Polymerization methods for aromatic vinyl-imide copolymers include, for example, solution polymerization and bulk polymerization. Solution polymerization is preferred from the viewpoint that an aromatic vinyl-imide copolymer with a more uniform copolymer composition can be obtained by carrying out polymerization while performing portionwise addition, etc. The solvent for solution polymerization is preferably non-polymerizable from the viewpoint that by-products are less likely to be generated and adverse effects are minimal. The polymerization process can be any of continuous polymerization, batch (batch) and semi-batch. The polymerization method is not particularly limited, but radical polymerization is preferred from the viewpoint that it allows for highly productive production through a simple process.

[0063] In the solution polymerization or bulk polymerization, the polymerization temperature is preferably in the range of 80 to 150°C, and a polymerization initiator and a chain transfer agent can be used. From the viewpoint of controlling the polymerization reaction rate and polymerization rate, it is preferable to use an azo compound or an organic peroxide having a 10-hour half-life at 70 to 120°C as the polymerization initiator.

[0064] Imide monomer units can be introduced into aromatic vinyl-imide copolymers by copolymerizing the imide monomer or by post-imidization. The post-imidization method is preferred because it reduces the amount of remaining imide monomer in the aromatic vinyl-imide copolymer. The post-imidization method involves copolymerizing a monomer mixture containing an aromatic vinyl monomer, an unsaturated acid anhydride monomer, and other copolymerizable monomers, and then reacting some of the unsaturated acid anhydride monomer units with ammonia or a primary amine to imidize and convert them into imide monomer units. During post-imidization, a catalyst can be used to enhance the dehydration ring-closure reaction in the reaction between the primary amine and the unsaturated dicarboxylic acid anhydride monomer units. Examples of catalysts include tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N,N-dimethylaniline, and N,N-diethylaniline. The post-imidization temperature is preferably 100°C to 250°C, more preferably 120°C to 200°C.

[0065] Known methods can be used to remove volatile components such as the solvent used in solution polymerization and unreacted monomers from the solution after solution polymerization of an aromatic vinyl-imide copolymer or from the solution after post-imidization (devolatilization method). For example, a vacuum devolatilization tank equipped with a heater or a devolatilization extruder equipped with a vent can be used. The devolatilized molten aromatic vinyl-imide copolymer is transferred to a granulation process, extruded into strands through a multi-hole die, and processed into pellets by cold cutting, in-air hot cutting, or underwater hot cutting.

[0066] The aromatic vinyl-imide copolymer may be prepared by any of the above methods, and a commercially available one may be used. Preferably, a copolymer prepared by post-imidization may be used. The aromatic vinyl-imide copolymer may be directly prepared by a commercially available method, and is not particularly limited thereto.

[0067] 3) Aromatic vinyl-vinyl cyanide resin According to one embodiment of the present invention, the recycled resin composition may further include an aromatic vinyl-vinyl cyanide-based resin. In this case, since the aromatic vinyl-vinyl cyanide-based resin is added in place of the copolymer added to the heat-resistant resin, the amount of the heat-resistant resin added can be relatively reduced. This allows the amounts of the aromatic vinyl-vinyl cyanide-based resin and the heat-resistant resin added to be appropriately adjusted according to the desired physical property levels. The aromatic vinyl-vinyl cyanide-based resin is an aromatic vinyl-vinyl cyanide-based copolymer and includes an aromatic vinyl-based monomer unit and a vinyl cyanide-based monomer unit. The types of these monomers may be selected from the types listed in the above description of the copolymer.

[0068] The copolymer can serve as a matrix in the recycled resin composition, and this copolymer has excellent heat resistance, impact resistance, and fluidity, and can play a fundamental role in realizing excellent physical properties of resin molded products.

[0069] The copolymer may have a weight-average molecular weight of, for example, 70,000 g / mol to 200,000 g / mol, preferably 80,000 g / mol to 180,000 g / mol, and more preferably 90,000 g / mol to 160,000 g / mol. Within this range, excellent chemical resistance, processability, and a good balance of physical properties are achieved. The copolymer can be produced by methods such as emulsion polymerization, suspension polymerization, bulk polymerization, and continuous bulk polymerization, and it is particularly preferable to use one produced by continuous bulk polymerization.

[0070] The copolymer may be a commercially available copolymer or may be obtained by a commercially available method, but is not particularly limited thereto.

[0071] Meanwhile, in yet another example according to one embodiment of the present invention, the heat-resistant resin in the recycled resin composition may be one or more copolymers, preferably two or more copolymers, selected from the group consisting of alkyl-substituted aromatic vinyl copolymers, aromatic vinyl-imide copolymers, and aromatic vinyl-vinyl cyanide copolymers. Strictly speaking, the aromatic vinyl-vinyl cyanide copolymer is not a resin that ensures heat resistance, but it can affect the final physical property trends of the recycled resin composition and is a basic resin for ensuring heat resistance and controlling the balance of physical properties. Therefore, it is included in the category of "heat-resistant resins" and can be appropriately selected and applied together with the other two copolymers.

[0072] others The recycled resin composition according to one embodiment of the present invention may further contain one or more additives selected from the group consisting of impact modifiers, lubricants, heat stabilizers, anti-dripping agents, antioxidants, light stabilizers, UV blockers, pigments, and inorganic fillers, if necessary. In this case, the additives may be used in an amount of 5.0 parts by weight or less, or 0.1 to 1.0 parts by weight, per 100 parts by weight of the total content of the resins and copolymers contained in the recycled resin composition.

[0073] Furthermore, the specific substances of the additives are not particularly limited as long as they are those used in general thermoplastic resin compositions. For example, in order to further improve flame retardancy, the anti-dripping agent may be one or more selected from the group consisting of Teflon (registered trademark), polyamide, polysilicone, PTFE (polytetrafluoroethylene), and TFE-HFP (tetrafluoroethylene-hexafluoropropylene) copolymer, and the inorganic filler may be one or more selected from the group consisting of barium sulfate, barium glass filler, and barium oxide.

[0074] Molded product The present invention provides a molded article comprising the recycled resin composition. For example, the molded article can be used in various industrial fields such as various electrical and electronic products and automotive parts. Common molding methods such as extrusion, injection, and casting can be used as the molding method.

[0075] Example While the present invention may be embodied in various different forms, it is to be understood that the invention is not limited to the specific embodiments set forth herein, and that the invention may be embodied in various different forms without departing from the spirit or scope of the present invention.

[0076] Examples and Comparative Examples The resins and copolymers used in the examples and comparative examples are as follows.

[0077] *(A) Graft resin: ABS resin (LG Chemical, DP270E) emulsion-polymerized with 60% butadiene, 10% acrylonitrile, and 30% styrene.

[0078] *(B-1) Alkyl-substituted aromatic vinyl copolymer: a copolymer polymerized with 67% by weight of alpha-methylstyrene, 5% by weight of styrene, and 28% by weight of acrylonitrile (LG Chemical, 99UH, Mw is 95,000)

[0079] *(B-2) Aromatic vinyl-imide copolymer: a copolymer bulk-polymerized with 52% by weight of N-phenylmaleimide, 2% by weight of maleic anhydride, and 46% by weight of styrene (DENKA, MS-NB)

[0080] *(C) Aromatic vinyl-vinyl cyanide resin: A copolymer polymerized with 31% by weight of acrylonitrile and 69% by weight of styrene (LG Chemical, 95RF)

[0081] *(D-1) Recycled graft resin A: ABS resin recycled from waste materials with Izod impact strength of 17.5 kgf·cm / cm, tensile strength of 47 MPa, and heat distortion temperature of 84°C.

[0082] *(D-2) Recycled graft resin B: ABS resin recycled from waste materials with an Izod impact strength of 9.6 kgf·cm / cm, a tensile strength of 45 MPa, and a heat distortion temperature of 86°C.

[0083] *(D-3) Recycled graft resin C: ABS resin recycled from waste materials with Izod impact strength of 9.6 kgf·cm / cm, tensile strength of 39 MPa, and heat distortion temperature of 82°C.

[0084] *(D-4) Recycled graft resin D: ABS resin recycled from waste materials with Izod impact strength of 5 kgf·cm / cm, tensile strength of 56 MPa, and heat distortion temperature of 85°C.

[0085] *(D-5) Recycled graft resin E: ABS resin recycled from waste materials with Izod impact strength of 19 kgf·cm / cm, tensile strength of 42 MPa, and heat distortion temperature of 80°C.

[0086] *(D-6) Recycled graft resin F: ABS resin recycled from waste materials with Izod impact strength of 6 kgf·cm / cm, tensile strength of 49 MPa, and heat distortion temperature of 92°C.

[0087] The resins and copolymers were blended in the same ratios as in Table 1 below to produce resin compositions for the Examples and Comparative Examples. All of the following contents are in parts by weight, and 1.0 part by weight of a lubricant (SUNKOO Chemical, Sunlube) and 0.3 part by weight of a stabilizer (BASF, Irganox-1076) were commonly added and blended.

[0088] [Table 1]

[0089] Experimental Example 1 The resin compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 7 were fed into a twin-screw extruder, kneaded and extruded at 240°C to prepare pellets. The pellets were extruded at 240°C to prepare test pieces, and the heat distortion temperature, Izod impact strength, tensile strength and paintability were measured using the following methods. The results are shown in Table 2 below.

[0090] (1) Heat deflection temperature (HDT, °C): According to ASTM D648, load 18.6 kgf / cm 2 The measurements were performed under the conditions of a heating rate of 120°C / hr and unannealed.

[0091] (2) Izod impact strength (kgf·cm / cm): In accordance with ASTM D256, a notch was made in a 6.4 mm thick sample at room temperature (23°C) to measure the notched Izod impact strength.

[0092] (3) Tensile strength (MPa): Measured in accordance with ASTM D638 at a cross head speed of 50 mm / min.

[0093] (4) Paintability: Test pieces were prepared to a size of 10 mm x 10 mm x 3.2 mm at the time of injection, and after degreasing with isopropyl alcohol (IPA), a silver metallic paint was applied, and the test pieces were dried at room temperature (25°C) for 5 minutes. After that, a clear coating liquid was applied and the test pieces were dried at 85°C for 30 minutes. The dried test pieces were then visually observed and evaluated according to the following criteria.

[0094] -○ (Excellent): No defects such as erosion are observed on the surface of the coating. -△ (Good): Fine paint erosion is observed on the painted surface. -× (deterioration): Erosion is clearly observed on the surface of the paint.

[0095] [Table 2]

[0096] Referring to Table 2, in Examples 1 to 10, which used recycled graft resins, the amount of virgin aromatic vinyl-vinyl cyanide resin (C), which can compensate for impact strength and tensile strength by using recycled resin, was reduced. However, considering that only 30% of resin (C) was used compared to Comparative Examples 1 to 5, which were composed entirely of virgin resins, the impact strength and tensile strength were not substantially impaired, and heat resistance was not affected. In fact, it can be seen that the use of recycled graft resins was superior in terms of paintability.

[0097] It was confirmed that Comparative Example 6, which uses a recycled graft resin with a tensile strength of less than 41 MPa, Comparative Example 7, which uses a recycled graft resin with a tensile strength of more than 54 MPa, Comparative Example 8, which uses a recycled graft resin with a heat distortion temperature of less than 82°C, and Comparative Example 9, which uses a recycled graft resin with a heat distortion temperature of more than 90°C, had inferior paintability compared to Examples 1 to 10.

Claims

1. a base resin including a graft resin and a heat-resistant resin; and a recycled graft resin, the heat-resistant resin is one or more copolymers selected from the group consisting of alkyl-substituted aromatic vinyl copolymers and aromatic vinyl-imide copolymers, The regenerated graft resin is The heat distortion temperature is 82°C to 90°C, A recycled resin composition having a tensile strength of 41 MPa to 54 MPa.

2. The recycled resin composition according to claim 1, wherein the recycled graft resin has a heat distortion temperature of 83°C to 88°C and a tensile strength of 43 MPa to 50 MPa.

3. The recycled resin composition according to claim 1, wherein the recycled graft resin has an Izod impact strength of 8 kgf·cm / cm to 25 kgf·cm / cm.

4. For 100 parts by weight of the recycled resin composition, The recycled resin composition according to claim 1, comprising 50 to 90 parts by weight of the base resin and 10 to 50 parts by weight of the recycled graft resin.

5. The recycled resin composition according to claim 1 , wherein the graft resin and the recycled graft resin each independently contain a conjugated diene polymer, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit.

6. The alkyl-substituted aromatic vinyl copolymer contains an alkyl-substituted aromatic vinyl monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit, The recycled resin composition according to claim 1, wherein the aromatic vinyl-imide copolymer contains an aromatic vinyl monomer unit, an imide monomer unit, and an unsaturated acid anhydride monomer unit.

7. The base resin further comprises an aromatic vinyl-vinyl cyanide resin; 2. The recycled resin composition according to claim 1, wherein the aromatic vinyl-vinyl cyanide resin contains an aromatic vinyl monomer unit and a vinyl cyanide monomer unit.

8. For 100 parts by weight of the recycled resin composition, The recycled resin composition according to claim 1, comprising 60 to 85 parts by weight of the base resin and 15 to 40 parts by weight of the recycled graft resin.

9. A molded article comprising the resin composition according to claim 1.

10. The molded article of claim 9, wherein the molded article is injection molded.

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