Recycled resin composition

Abstract

The present invention relates to a recycled resin composition comprising: a base resin comprising a graft resin and a heat-resistant resin, and a recycled graft resin, the heat-resistant resin is at least one copolymer selected from the group consisting of an alkyl-substituted aromatic vinyl-based copolymer and an aromatic vinyl-imide-based copolymer, and the recycled graft resin has a heat distortion temperature of 82 DEG C to 90 DEG C and a tensile strength of 41 MPa to 54 MPa, and thus, the heat-resistant resin has excellent heat resistance and heat resistance. Recycled resins that are environmentally friendly and do not deteriorate in thermal and mechanical properties can be provided.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10 - 2022 - 0167407, filed with the Korean Intellectual Property Office on December 5, 2022, the disclosure of which is incorporated herein by reference in its entirety. Technical field

[0003] The present invention relates to a recycled resin composition that is environmentally friendly and has no deteriorated physical properties. Background art

[0004] The rapid progress of high - tech materials and devices has led to the emergence of various new technologies and the continuous development of various technical instruments. Therefore, the consumption of electrical and electronic devices has increased, prompting the continuous generation of waste electrical and electronic devices. Plastics are low - risk and inexpensive, so they are widely used in electrical and electronic devices, but due to characteristics such as low compressibility and high elasticity, they occupy a large volume during the recycling process, making recycling difficult.

[0005] At the same time, as environmental concerns increase worldwide, regulations have become more stringent to reduce carbon dioxide emissions. In particular, in recent years, environmental pollution caused by the increasing use of plastics has become a serious problem. Therefore, as a trend of the global circular economy, led by the United States, more and more countries are introducing extended producer responsibility (EPR) for plastics, strengthening regulations in the manufacturing stage (such as mandating the use of recycled resins), increasingly adopting plastic taxes and carbon border taxes, and thus, are exploring various ways to recycle waste plastics and introduce bio - materials.

[0006] Therefore, manufacturers need to add more than a certain amount of recycled resin when manufacturing resin - molded products and give a green grade according to the amount of recycled resin.

[0007] However, recycled resin is a processed resin, so it contains additives such as colorants, lubricants, and mold release agents, and has been processed at high temperatures, so its properties change. When the amount of recycled resin increases, it inevitably leads to more deteriorated physical properties compared to conventional resins. In particular, when manufacturing molded products, recycled resin does not have sufficient chemical resistance to organic solvents, detergents, or fragrances used in post - treatment processes, resulting in cracking or breakage, so it is difficult to commercialize as a product.

[0008] Therefore, a technology using recycled resin needs to be developed to allow products to be environmentally friendly and to have minimal deterioration of thermal and mechanical properties compared to conventional new plastic products when applied in actual industry, thus achieving actual commercialization.

[0009] Prior art documents

[0010] [Patent Document]

[0011] (Patent Document 1) Korean Patent Publication No. 10-2016-0144185 Summary of the Invention

[0012] Technical Problem

[0013] One aspect of the present invention provides a recycled resin composition which exhibits environmental friendliness by using recycled resin recycled from waste resin, minimizes deterioration of thermal properties such as heat resistance and mechanical properties such as tensile strength and impact strength, and provides excellent paintability, thereby substituting virgin resin.

[0014] Technical Solution

[0015] According to one aspect of the present invention, there is provided a recycled resin composition comprising: a base resin comprising a graft resin and a heat-resistant resin, and a recycled graft resin, wherein the heat-resistant resin is at least one copolymer 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.

[0016] In addition, according to another aspect of the present invention, there is provided a molded article comprising the above-mentioned recycled resin composition.

[0017] Advantageous Effects

[0018] The recycled resin composition of the present invention can ensure environmental friendliness by using recycled resin recycled from waste resin, and although relatively less virgin resin is introduced due to the use of recycled resin, it minimizes deterioration of thermal properties and mechanical properties while providing excellent paintability, and thus can sufficiently substitute virgin resin. Detailed Description

[0019] Hereinafter, the present invention will be described in detail to assist in understanding the present invention.

[0020] It will be understood that words or terms used in the specification and claims should not be construed as having the meaning defined in a commonly used dictionary, and it will also be understood that based on the principle that the inventor can appropriately define the meaning of words or terms to best explain the present invention, the words or terms should be construed as having a meaning consistent with their meaning in the context of the relevant art and the technical idea of the present invention.

[0021] Unless otherwise defined separately, the terms and measurement methods used in the present invention can be defined as follows.

[0022] As used herein, the term "composition" includes reaction products and decomposition products formed from the materials of the composition and mixtures containing the materials of the composition.

[0023] As used herein, the term "monomeric unit" or "monomer-derived unit" may refer to a repeating unit formed by a compound used as a monomer participating in a polymerization reaction, a structure derived therefrom, or the material itself.

[0024] As used herein, the term "derivative" may refer to a compound having a structure in which at least one hydrogen atom constituting the original compound is substituted by a halogen group, an alkyl group, or a hydroxyl group.

[0025] In this text, "polymerization conversion rate" refers to the degree to which monomers are polymerized through a polymerization reaction to form a polymer, and can be calculated by taking out some polymer in the reactor during the polymerization process and calculating the weight of the polymer excluding moisture using the following Equation 3, then dissolving the sample in a tetrahydrofuran (THF) solvent and precipitating the resulting product with methanol (MeOH) to remove unreacted monomers, and then measuring the weight of the polymer obtained by drying the precipitated suspension, so as to be calculated by the following Equation 4.

[0026] [Equation 3]

[0027] (Weight of the actual polymer) = (Collected polymer) - (Collected polymer × moisture content)

[0028] [Equation 4]

[0029] Polymerization conversion rate (%) = [(Weight of the polymer obtained by drying) / (Weight of the actual polymer)] × 100

[0030] Recycled Resin Composition

[0031] The recycled resin composition of the present invention comprises: a base resin comprising a graft resin and a heat-resistant resin, and a recycled graft resin, wherein the heat-resistant resin is at least one copolymer selected from the group consisting of alkyl-substituted aromatic vinyl copolymers and aromatic vinyl-imide copolymers, and the heat distortion temperature of the recycled graft resin is 82°C to 90°C, and the tensile strength is 41 MPa to 54 MPa.

[0032] Generally, when manufacturing a molded article by mixing two or more resins, at least any one of the mixed resins serves as a matrix (continuous phase), while the other resins serve as fillers (dispersed phase). However, in the case of applying a recycled graft resin as a filler as described in the present invention, when replacing the same virgin graft resin, the recycled graft resin may not meet the basic level of required physical properties and may not be able to compensate for the reduced physical properties through techniques such as adding other resins or additives. Therefore, when applying a recycled graft resin, a method of using a resin instead of the matrix is employed. However, the resin used as the matrix also has the same problem as described above. Therefore, when intending to use a recycled graft resin, a method for minimizing the deterioration of processability or final physical properties is required, and the present invention aims to provide a way to solve this task.

[0033] According to an embodiment of the present invention, the recycled resin composition is environmentally friendly and can respond to plastic-related environmental problems by using a recycled graft resin recycled from waste resins. There is no deterioration in thermal and mechanical properties that may be caused by a reduction in the input of virgin resins due to the use of recycled resins, and it has excellent paintability. Therefore, it can fully replace virgin resins in the same field.

[0034] Furthermore, in order to ensure that the thermal and mechanical properties and paintability are not deteriorated, a graft resin and a heat-resistant resin are included together with the recycled graft resin as base resins, and the above-mentioned benefits can be more effectively achieved through this combination.

[0035] Recycled Graft Resin

[0036] According to an embodiment of the present invention, the recycled resin composition contains a recycled graft resin. In terms of physical properties, a recycled graft resin with a heat distortion temperature of 82°C to 90°C and a tensile strength of 41 MPa to 54 MPa is selected. The recycled graft resin is a graft resin that can be formed through a separate recycling process after a plastic product to which an acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as "ABS resin") is applied is discarded.

[0037] 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 unit is the same as that of the graft resin, and thus will be described in the description of the graft resin below.

[0038] According to an embodiment of the present invention, the recycled graft resin needs to satisfy specific physical properties, and one of the properties is the heat distortion temperature, which is a thermal property, and the heat distortion temperature can be 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. When using a recycled graft resin with a heat distortion temperature lower than 82°C, the heat resistance of the molded product may not be ensured, and its mechanical properties may be reduced. When using a recycled graft resin with a temperature higher than 90°C, the paintability of the molded product may be uneven, or erosion may occur.

[0039] In addition, according to an embodiment of the present invention, the physical property that the recycled graft resin needs to satisfy is the tensile strength, and the tensile strength needs to be in the range of 41 MPa to 54 MPa, and can be 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 in the present invention preferably satisfies the above range. When using a recycled graft resin with a tensile strength greater than 54 MPa, the recycled graft resin may not be well dispersed in the matrix resin, and may have non-uniform paintability or cause erosion. In addition, when using a recycled graft resin with a tensile strength lower than 41 MPa, the molded product itself may also have poor tensile strength. Therefore, it is advantageous to use a recycled graft resin with a tensile strength within the above range.

[0040] Meanwhile, regarding the tensile strength of the ABS resin, even in the case of the recycled ABS resin made from recycled virgin ABS resin, compared with the virgin ABS resin, the tensile strength of the recycled resin does not tend to decrease significantly. Therefore, it is advantageous to apply a recycled graft resin with an appropriate level of tensile strength, and it is generally considered that the higher the tensile strength, the better. However, in the present invention, when the tensile strength of the recycled graft resin satisfies the above range rather than just being high, it can be more suitable for achieving the effects of the present invention.

[0041] In addition, according to an embodiment of the present invention, it is advantageous to apply a recycled graft resin whose Izod impact strength is 8 kgf·cm / cm to 25 kgf·cm / cm. The Izod impact strength can be more preferably 9 kgf·cm / cm to 20 kgf·cm / cm, and more preferably 9 kgf·cm / cm to 18 kgf·cm / cm. Similar to the case of tensile strength, when the impact strength has a suitable value rather than just being high, it is also more suitable for achieving the effects of the present invention.

[0042] According to an embodiment of the present invention, with respect to 100 parts by weight of the recycled resin composition, the content of the base resin may be from 50 parts by weight to 90 parts by weight; and the content of the recycled graft resin may be from 10 parts by weight to 50 parts by weight. In addition, preferably, the content of the base resin may be from 60 parts by weight to 85 parts by weight; and the content of the recycled graft resin may be from 15 parts by weight to 40 parts by weight. When the addition amount of the recycled graft resin is greater than 10 parts by weight, this may be the minimum requirement to meet the environmentally friendly purpose and achieve a uniform and non-corrosive painted surface of the molded article, while when the addition amount of the recycled graft resin is less than 50 parts by weight, the uniformity of excellent physical properties can be ensured, and the minimum amount of virgin resin required to ensure the minimum physical properties necessary for commercialization can be obtained.

[0043] Base Resin 1: Graft Resin

[0044] According to an embodiment of the present invention, the recycled resin composition contains a base resin, and the base resin contains a graft resin. With respect to 100 parts by weight of the recycled resin composition, the content of the graft resin may be from 5 parts by weight to 50 parts by weight, from 10 parts by weight to 40 parts by weight, and from 15 parts by weight to 35 parts by weight, and within this range, excellent impact strength and tensile strength can be achieved, and the paintability can also be improved.

[0045] 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, and the acrylonitrile-butadiene-styrene copolymer is used to provide excellent moldability and impact resistance to the recycled resin composition, and may be a graft copolymer having 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.

[0046] According to an embodiment of the present invention, the acrylonitrile-butadiene-styrene copolymer may be prepared by emulsion polymerization and emulsion graft polymerization, and for example, it may be prepared by the following method: emulsion polymerizing a conjugated diene monomer to prepare a rubber-like polymer core (or seed), adding a vinyl cyanide monomer and an aromatic vinyl monomer to the core, and performing emulsion graft polymerization.

[0047] In addition, the acrylonitrile-butadiene-styrene copolymer may comprise: a core in an amount of 30% to 70% by weight containing units derived from conjugated diene monomers; and a shell surrounding the core and containing units derived from aromatic vinyl monomers and units derived from vinyl cyanide monomers, and in this case, the shell may contain units derived from aromatic vinyl monomers and units derived from vinyl cyanide monomers in a weight ratio of 7:3 to 8:2, and in this case, the copolymer may have further improved impact resistance, mechanical properties, and moldability.

[0048] According to an embodiment of the present invention, the conjugated diene monomer of the acrylonitrile-butadiene-styrene copolymer may be one or more 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 may specifically be 1,3-butadiene.

[0049] According to an embodiment of the present invention, the aromatic vinyl monomer may be one or more selected from the group consisting of styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, o-methylstyrene, o-tert-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, and their derivatives, and may specifically be styrene.

[0050] Relative to 100 parts by weight of the aromatic vinyl monomer and vinyl cyanide monomer constituting the shell, the addition amount of the aromatic vinyl monomer may be 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, and within this range, there are the following effects: obtaining a copolymer with a high polymerization conversion rate, and achieving excellent compatibility with thermoplastic resins while maintaining the mechanical properties of the copolymer.

[0051] According to an embodiment of the present invention, the vinyl cyanide monomer may be one or more selected from the group consisting of acrylonitrile, methacrylonitrile, ethylacrylonitrile, and their derivatives, and may specifically be acrylonitrile.

[0052] In addition, according to an embodiment of the present invention, relative to 100 parts by weight of the aromatic vinyl monomer and vinyl cyanide monomer constituting the shell, the addition amount of the vinyl cyanide monomer may be 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, and within this range, there are the following effects: obtaining a copolymer with a high polymerization conversion rate, and achieving excellent compatibility with thermoplastic resins while maintaining the mechanical properties of the copolymer.

[0053] According to an embodiment of the present invention, the conjugated diene monomer of the unsaturated ester graft copolymer may be one or more 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 may specifically be 1,3-butadiene.

[0054] Meanwhile, the graft resin according to an embodiment of the present invention may be copolymerized by further adding an unsaturated ester monomer to the shell. The unsaturated ester monomer may be an alkyl (meth)acrylate monomer, and the alkyl (meth)acrylate monomer may be one or more 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, and specifically, the alkyl (meth)acrylate monomer may be one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate.

[0055] When an unsaturated ester monomer is further included as a constituent monomer of the shell for emulsion graft polymerization, its content may be appropriately adjusted, and the unsaturated ester monomer may be included as a main component or as a minor component, and this may be appropriately selected according to the desired physical properties.

[0056] The graft resin may be a commercially available resin and may be obtained by a commercially available method, and is not particularly limited thereto. In addition, the recycled graft resin may have the same components as the virgin graft resin, but may be prepared by a predetermined recycling process after the virgin graft resin is discarded.

[0057] Base Resin 2: Heat-Resistant Resin

[0058] According to an embodiment of the present invention, the recycled resin composition includes a base resin, and the base resin includes a heat-resistant resin. The content of the heat-resistant resin may be 10 to 70 parts by weight, 20 to 60 parts by weight, and 25 to 55 parts by weight relative to 100 parts by weight of the recycled resin composition, and within this range, heat resistance can be obtained, the deterioration of impact strength and tensile strength can be minimized, and the paintability can also be improved. The heat-resistant resin is applied by using one copolymer selected from the group consisting of alkyl-substituted aromatic vinyl copolymers and aromatic vinyl-imide copolymers or by including two copolymers.

[0059] Two copolymers used as heat-resistant resins can ensure the heat resistance of the recycled resin composition and are added as essential components. In particular, an alkyl-substituted aromatic vinyl copolymer can balance heat-resistant properties and mechanical properties such as heat resistance, tensile strength, and impact strength, and an aromatic vinyl-imide copolymer can be particularly advantageous in obtaining thermal properties. In the case of including two copolymers that can be used as heat-resistant resins, the input ratio as the weight ratio of the alkyl-substituted aromatic vinyl copolymer to the aromatic vinyl-imide copolymer can be from 90:10 to 10:90, and can be from 90:10 to 30:70, from 90:10 to 40:60, or from 90:10 to 50:50.

[0060] 1) Alkyl-Substituted Aromatic Vinyl Copolymer

[0061] According to an embodiment of the present invention, the alkyl-substituted aromatic vinyl copolymer may include alkyl-substituted aromatic vinyl monomer units, aromatic vinyl monomer units, and vinyl cyanide monomer units.

[0062] According to an 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, o-tert-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, and derivatives thereof, and may specifically be α-methylstyrene.

[0063] With respect to a total input amount of 100 parts by weight of monomers, the addition amount of the alkyl-substituted aromatic vinyl monomer may be 30 parts by weight to 95 parts by weight, 40 parts by weight to 90 parts by weight, 50 parts by weight to 85 parts by weight, or 60 parts by weight to 80 parts by weight, and within this range, there are the following effects: obtaining a copolymer with a high polymerization conversion rate, maintaining the mechanical properties of the copolymer, and obtaining thermal properties, so as to excellently maintain the balance between physical properties.

[0064] 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 thus will not be described herein again.

[0065] With respect to a total input amount of 100 parts by weight of monomers, the addition amount of the aromatic vinyl monomer may be 1 part by weight to 20 parts by weight, 2 parts by weight to 15 parts by weight, or 5 parts by weight to 15 parts by weight, and it may be different from the alkyl-substituted aromatic vinyl monomer, and as a similar monomer, the input amount may be relatively small.

[0066] In addition, according to an embodiment of the present invention, with respect to a total input amount of 100 parts by weight of monomers, the addition amount of vinyl cyanide monomers may be 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, and within this range, there are the following effects: obtaining a copolymer with a high polymerization conversion rate, and maintaining the mechanical properties and excellent thermal properties of the copolymer to maintain the balance between physical properties.

[0067] For example, the weight average molecular weight of the copolymer may be 40,000 g / mol to 200,000 g / mol, preferably 50,000 g / mol to 150,000 g / mol, more preferably 70,000 g / mol to 130,000 g / mol, and within this range, it has excellent chemical resistance, excellent processability, and a balance of physical properties. The copolymer can be prepared by emulsion polymerization, suspension polymerization, bulk polymerization, continuous bulk polymerization, etc., and continuous bulk polymerization is preferred.

[0068] The alkyl-substituted aromatic vinyl copolymer may be a commonly commercially available alkyl-substituted aromatic vinyl copolymer, and can be obtained by a commercially available method, and is not particularly limited thereto.

[0069] 2) Aromatic Vinyl-Imide Copolymer

[0070] According to an embodiment of the present invention, the aromatic vinyl-imide copolymer may include aromatic vinyl monomer units, imide monomer units, and unsaturated acid anhydride monomer units.

[0071] The aromatic vinyl monomers are the same as those described above, and thus will not be described again.

[0072] According to an embodiment of the present invention, the imide monomer may be a maleimide monomer, and as a specific example, it may be a maleimide monomer in which the hydrogen bonded to the N atom of maleimide is substituted by a substituent. As a more specific example, the imide monomer may be selected from the group consisting of N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-tert-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, and as a specific example, it may be N-phenylmaleimide.

[0073] According to an embodiment of the present invention, the addition amount of the imide monomer may be 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 the total amount of the introduced monomers. And within this range, there are the following effects: obtaining a copolymer with a high polymerization conversion rate, preparing a copolymer having a uniform monomer unit composition, and obtaining a copolymer having excellent heat resistance.

[0074] According to an embodiment of the present invention, the unsaturated acid anhydride monomer may be, for example, one or more selected from the group consisting of maleic anhydride, itaconic anhydride, citraconic anhydride, and aconitic anhydride, and may specifically be maleic anhydride.

[0075] According to an embodiment of the present invention, the addition amount of the unsaturated acid anhydride monomer may be 1 to 50 parts by weight, 5 to 40 parts by weight, or 5 to 30 parts by weight. And within this range, there are the following effects: obtaining a copolymer with a high polymerization conversion rate, preparing a copolymer having a uniform monomer unit composition, and obtaining a copolymer having excellent heat resistance.

[0076] As a method for preparing an aromatic vinyl-imide copolymer, a known method can be applied. 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. In addition, there is a method of copolymerizing a monomer mixture containing an aromatic vinyl monomer, an unsaturated acid anhydride monomer, and other copolymerizable monomers, then reacting a part of the unsaturated acid anhydride monomer units with ammonia or a primary amine to undergo imidization, and then converting them into imide monomer units (hereinafter referred to as "post-imidization method").

[0077] The polymerization mode of the aromatic vinyl-imide copolymer is, for example, solution polymerization or bulk polymerization. Considering obtaining an aromatic vinyl-imide copolymer with a more uniform copolymer composition by polymerizing with separate addition, solution polymerization is preferred. Considering that almost no by-products are generated and adverse effects are less likely to occur, the solvent for solution polymerization is preferably non-polymerizable. Any one of a continuous polymerization process, a batch process (batch), and a semi-batch process can be applied as the polymerization process. The polymerization method is not particularly limited, but radical polymerization is preferably used as a manufacturing method by a simple method with high productivity.

[0078] The polymerization temperature of solution polymerization or bulk polymerization may preferably be 80°C to 150°C, and it can be carried out using a polymerization initiator and a chain transfer agent. And for controlling the polymerization reaction rate and polymerization rate, it is advantageous to use an azo compound or an organic peroxide having a 10-hour half-life temperature of 70°C to 120°C as the polymerization initiator.

[0079] The introduction of the imide monomer units of the aromatic vinyl-imide copolymers includes a method of copolymerizing imide monomers and a post-imidation method. The post-imidation method is advantageous because it reduces the amount of residual imide monomers in the aromatic vinyl-imide copolymers. The post-imidation method is a method of copolymerizing a monomer mixture containing aromatic vinyl monomers, unsaturated acid anhydride monomers, and other copolymerizable monomers, and then reacting a part of the unsaturated acid anhydride monomer units with ammonia or a primary amine to cause imidation, and then converting them into imide monomer units. In the post-imidation, a catalyst can be used to improve the dehydration cyclization reaction in the reaction of the primary amine with the unsaturated dicarboxylic anhydride monomer units. The catalyst is, for example, the following tertiary amines: trimethylamine, triethylamine, tripropylamine, tributylamine, N,N-dimethylaniline, or N,N-diethylaniline. The post-imidation temperature is preferably from 100 °C to 250 °C, more preferably from 120 °C to 200 °C.

[0080] Known methods can be employed as a method (devolatilization method) for removing volatile components such as the solvent for solution polymerization and unreacted monomers from the solution after the solution polymerization reaction or after the post-imidation of the aromatic vinyl-imide copolymers. 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 can be transferred to a granulation process, extruded in the form of strands from a porous die, and processed into pellets by a cold cutting method, an air thermal cutting method, or an underwater thermal cutting method.

[0081] The aromatic vinyl-imide copolymers can be any of those commercially available and prepared by any of the above methods, and can preferably be those prepared by post-imidation, and the aromatic vinyl-imide copolymers can be directly prepared by a commercial method and are not particularly limited thereto.

[0082] 3) Aromatic Vinyl-Vinyl Cyanide Resin

[0083] According to an embodiment of the present invention, the recycled resin composition may further contain an aromatic vinyl-vinyl cyanide resin. In this case, the aromatic vinyl-vinyl cyanide resin can be added in place of the copolymer added as a heat-resistant resin, so the input amount of the heat-resistant resin can be relatively small. Therefore, the input amount of the aromatic vinyl-vinyl cyanide resin and the input amount of the heat-resistant resin can be appropriately adjusted according to the required physical property level. The aromatic vinyl-vinyl cyanide resin is an aromatic vinyl-vinyl cyanide copolymer and contains aromatic vinyl monomer units and vinyl cyanide monomer units, and the types of these monomers can be equivalently selected from the types listed in the description of the above copolymers.

[0084] The copolymer can be used as a matrix in the recycled resin composition, and the copolymer has excellent heat resistance and impact resistance, and also has excellent fluidity, so it can be used as the basis for achieving excellent physical properties of resin molded articles.

[0085] For example, the weight-average molecular weight of the copolymer can be from 70,000 g / mol to 200,000 g / mol, preferably from 80,000 g / mol to 180,000 g / mol, more preferably from 90,000 g / mol to 160,000 g / mol, and within this range, it has excellent chemical resistance, excellent processability, and a balance of physical properties. The copolymer can be prepared by emulsion polymerization, suspension polymerization, bulk polymerization, continuous bulk polymerization, etc., and continuous bulk polymerization is preferred.

[0086] The copolymer can be a commonly commercially available copolymer and can be obtained by commercially available methods, and is not particularly limited thereto.

[0087] Meanwhile, as another example of an embodiment of the present invention, in the recycled resin composition, the heat-resistant resin can be at least one copolymer selected from the group consisting of alkyl-substituted aromatic vinyl copolymers, aromatic vinyl-imide copolymers, and aromatic vinyl-vinyl cyanide copolymers, preferably at least two copolymers. Strictly speaking, the aromatic vinyl-vinyl cyanide copolymer is not a resin for obtaining heat resistance, but a resin that can affect the final physical property trend of the recycled resin composition, and is the basis for obtaining heat resistance and controlling the balance of physical properties, and is included in the category of "heat-resistant resin", and can be appropriately selected and applied together with the other two copolymers.

[0088] Others

[0089] If necessary, the recycled resin composition of an 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, ultraviolet blockers, pigments, and inorganic fillers, and in this case, the amount of the additive can be 5.0 parts by weight or less, or from 0.1 part by weight to 1.0 part by weight, based on the total amount of the resin and copolymer contained in 100 parts by weight of the recycled resin composition.

[0090] In addition, there is no specific limitation on the specific material of the additive, as long as the material is used in a conventional thermoplastic resin composition. For example, considering further improvement of flame retardancy, the anti-dripping agent can be one or more selected from the group consisting of Teflon, polyamide, polysiloxane, polytetrafluoroethylene (PTFE), and tetrafluoroethylene-hexafluoropropylene (TFE-HFP) copolymer, and the inorganic filler can be one or more selected from the group consisting of barium sulfate, barium glass filler, and barium oxide.

[0091] Molded Product

[0092] The present invention provides a molded article containing the above-mentioned recycled resin composition. For example, the molded article can be applied to various industrial fields, such as various electrical and electronic products and automotive parts. As the molding method, conventional molding methods such as extrusion, injection, and casting can be applied.

[0093] Examples

[0094] Hereinafter, examples of the present invention will be described in detail in a manner that can be easily implemented by those skilled in the art to which the present invention pertains. However, the present invention can be implemented in many different forms and is not limited to the examples described herein.

[0095] Examples and Comparative Examples

[0096] The resins and copolymers used in the examples and comparative examples are as follows.

[0097] *(A) Graft resin: An ABS resin emulsion obtained by polymerizing 60% by weight of butadiene, 10% by weight of acrylonitrile, and 30% by weight of styrene (LG Chem., Ltd., DP270E)

[0098] *(B-1) Alkyl-substituted aromatic vinyl copolymer: A copolymer obtained by polymerizing 67% by weight of α-methylstyrene, 5% by weight of styrene, and 28% by weight of acrylonitrile (LG Chem., Ltd., 99UH, Mw is 95000)

[0099] *(B-2) Aromatic vinyl-imide copolymer: A copolymer obtained by bulk polymerization of 52% by weight of N-phenylmaleimide, 2% by weight of maleic anhydride, and 46% by weight of styrene (DENKA, MS-NB)

[0100] *(C) Aromatic vinyl-vinyl cyanide resin: A copolymer obtained by polymerizing 31% by weight of acrylonitrile and 69% by weight of styrene (LG Chem., Ltd., 95RF)

[0101] *(D-1) Recycled graft resin A: An ABS resin recycled from waste products with a notched Izod impact strength of 17.5 kgf·cm / cm, a tensile strength of 47 MPa, and a heat distortion temperature of 84 °C

[0102] *(D-2) Recycled graft resin B: An ABS resin recycled from waste products with a notched Izod impact strength of 9.6 kgf·cm / cm, a tensile strength of 45 MPa, and a heat distortion temperature of 86 °C

[0103] *(D-3) Recycled graft resin A: An ABS resin recycled from waste products with a notched Izod impact strength of 9.6 kgf·cm / cm, a tensile strength of 39 MPa, and a heat distortion temperature of 82 °C

[0104] *(D-4) Recycled graft resin D: An ABS resin recycled from waste products with a notched Izod impact strength of 5 kgf·cm / cm, a tensile strength of 56 MPa, and a heat distortion temperature of 85 °C

[0105] *(D-5) Recycled graft resin E: An ABS resin recycled from waste products with a notched Izod impact strength of 19 kgf·cm / cm, a tensile strength of 42 MPa, and a heat distortion temperature of 80 °C

[0106] *(D-6) Recycled graft resin F: An ABS resin recycled from waste products with a notched Izod impact strength of 6 kgf·cm / cm, a tensile strength of 49 MPa, and a heat distortion temperature of 92 °C

[0107] The resin compositions of the examples and comparative examples were prepared by mixing the above resins and copolymers at the ratios shown in Table 1 below. All of the following amounts are in parts by weight, and generally 1.0 part by weight of a lubricant (SUNKOOChemical, Sunlube) and 0.3 part by weight of a stabilizer (BASF, Irganox-1076) were added and mixed.

[0108] [Table 1]

[0109] (A) (B-1) (B-2) (C) (D-1) (D-2) (D-3) (D-4) (D-5) (D-6) Example 1 25 35 - 10 30 - - - - - Example 2 25 35 - 10 - 30 - - - - Example 3 22 43 5 - 30 - - - - - Example 4 22 - 12 36 30 - - - - - Example 5 22 - 12 36 - 30 - - - - Example 6 20 38 12 - 30 - - - - - Example 7 20 38 12 - - 30 - - - - Example 8 20 - 20 30 - 30 - - - - Example 9 25 35 - 25 15 - - - - - Example 10 25 35 - - - 40 - - - - Comparative Example 1 25 35 - 40 - - - - - - Comparative Example 2 22 43 5 30 - - - - - - Comparative Example 3 22 - 12 66 - - - - - - Comparative Example 4 20 38 12 30 - - - - - - Comparative Example 5 20 - 20 60 - - - - - - Comparative Example 6 25 35 - 10 - - 30 - - - Comparative Example 7 25 35 - 10 - - - 30 - - Comparative Example 8 25 35 - 10 - - - - 30 - Comparative Example 9 25 35 - 10 - - - - - 30

[0110] Experimental Example 1

[0111] The resin compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 7 were put into a twin-screw extruder and kneaded and extruded at 240 °C to prepare pellets. For the samples injection-molded from the pellets at 240 °C, the heat distortion temperature, notched Izod impact strength, tensile strength, and paintability were measured using the following methods, and the results are shown in Table 2 below.

[0112] (1) Heat deflection temperature (HDT, °C): Measured according to ASTM D648 under the conditions of a load of 18.6 kgf / cm 2 , a heating rate of 120 °C / hour and without annealing.

[0113] (2) Izod impact strength (kgf·cm / cm): According to ASTM D256, the notched Izod impact strength was measured by slotting the sample at room temperature (23 °C) using a 6.4 mm thick sample.

[0114] (3) Tensile strength (MPa): Measured according to ASTM D638 under the condition of a crosshead speed of 50 mm / min.

[0115] (4) Paintability: After injection, the sample was prepared into 10 mm × 10 mm × 3.2 mm and degreased with isopropyl alcohol (IPA), then coated with silver metal paint, dried at room temperature (25 °C) for 5 minutes, then coated with a transparent paint solution and dried at 85 °C for 30 minutes. Thereafter, the dried sample was observed with the naked eye and evaluated based on the following criteria.

[0116] -〇 (Excellent): No defects such as erosion were observed on the paint surface.

[0117] -△ (Good): Slight paint erosion was observed on the paint surface.

[0118] -X (Poor): Erosion was clearly observed on the paint surface.

[0119] [Table 2]

[0120] Heat Deflection Temperature Impact Strength Tensile Strength Paintability Example 1 93 21 43 〇 Example 2 92 20 44 〇 Example 3 98 17 44 △ Example 4 98 16 43 〇 Example 5 97 15 43 〇 Example 6 103 15 43 △ Example 7 102 14 43 △ Example 8 102 13 43 〇 Example 9 94 20 44 〇 Example 10 91 21 42 △ Comparative Example 1 94 27 48 〇 Comparative Example 2 99 19 49 〇 Comparative Example 3 99 18 48 〇 Comparative Example 4 104 15 51 △ Comparative Example 5 104 14 50 △ Comparative Example 6 91 17 39 X Comparative Example 7 95 13 47 X Comparative Example 8 89 22 41 X Comparative Example 9 95 13 44 X

[0121] Referring to Table 2, it was confirmed that, compared with Comparative Examples 1 to 5 composed entirely of virgin resin, considering that 30% of resin (C) was not added, in Examples 1 to 10 where recycled graft resin was applied, the impact strength and tensile strength did not deteriorate significantly, the heat resistance was not affected, and although the input amount of virgin aromatic vinyl-vinyl cyanide-based resin (C) that could compensate for the impact strength and tensile strength due to the use of recycled resin was reduced, the paintability was better when using recycled graft resin.

[0122] Comparative Example 6 using a recycled graft resin with a tensile strength of less than 41 MPa, Comparative Example 7 using a recycled graft resin with a tensile strength of more than 54 MPa, Comparative Example 8 using a recycled graft resin with a heat distortion temperature of less than 82 °C, and Comparative Example 9 using a recycled graft resin with a heat distortion temperature of more than 90 °C showed worse paintability than Examples 1 to 10.

Claims

1. A recycled resin composition, the recycled resin composition comprising: A base resin comprising a graft resin and a heat-resistant resin; and Recycled graft resin, Among them, The heat-resistant resin is at least one copolymer 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.

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 a cantilever beam impact strength of 8 kgf·cm / cm to 25 kgf·cm / cm.

4. The recycled resin composition according to claim 1, wherein Relative to 100 parts by weight of the recycled resin composition, the content of the base resin is 50 parts by weight to 90 parts by weight, and the content of the recycled graft resin is 10 parts by weight to 50 parts by weight.

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

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

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

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

9. A molded article comprising the resin composition of claim 1.

10. The molded article according to claim 9, wherein, The molded article is injection molded.