Thermoplastic resin composition

Abstract

The present invention relates to a thermoplastic resin composition, which comprises: a graft polymer including a shell containing a rubber and vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the rubber; and a non-graft polymer containing vinyl aromatic monomer units and vinyl cyanide monomer units, wherein the rubber is natural rubber or a rubber mixture containing natural rubber and synthetic rubber; and the biomass content measured in accordance with ASTM D6866 is 20.0 to 50.0% by weight.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0022182, filed February 20, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a thermoplastic resin composition. [Background technology]

[0003] Diene graft polymers include a diene rubbery polymer and a shell containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted onto the diene rubbery polymer. Diene graft polymers have an excellent balance of physical properties, such as fluidity, impact resistance, and gloss, and are widely used in the home appliance and automotive fields. However, the raw materials used in the manufacturing process are petrochemical-based compounds, which have a negative impact on the environment.

[0004] With growing interest in sustainable development, products using recycled diene graft polymers or bio-based plastics are being developed. Bio-based plastics are materials that focus on reducing carbon dioxide emissions by adding carbon-neutral plant biomass. Bio-based plastics are classified based on their biomass content and whether they contain heavy metals. The biomass content of bio-based plastics is determined based on the radiocarbon (C14) content measured in accordance with ASTM D6866. This is because plants fix carbon from the atmosphere through photosynthesis, so the ratio of radiocarbon in living animals and plants matches that in the air, and radiocarbon has a specific half-life. Countries around the world recognize bio-based plastics based on their biomass content measured in accordance with ASTM D6866. Specifically, South Korea, the United States, and Japan recognize plastics with a biomass content of 25.0% by weight or more, while Germany recognizes plastics with a biomass content of 20.0% by weight or more.

[0005] On the other hand, natural rubber is a natural material produced by extracting extracts from the rubber tree (Hevea brasiliensis), and because the tree fixes carbon dioxide as it grows, it can be used as an environmentally friendly raw material. There have been attempts to produce diene graft polymers using natural rubber, but because rubber products use both natural and synthetic rubber, the carbon reduction effect is not significant and it has been difficult to meet the biomass content requirements set by various countries. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP5270101B Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a thermoplastic resin composition that has excellent basic physical properties, a large carbon reduction effect, and can be recognized as a bio-based plastic by countries around the world. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, 1) the present invention provides a thermoplastic resin composition comprising: a graft polymer including a rubber and a shell containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the rubber; and a non-graft polymer containing vinyl aromatic monomer units and vinyl cyanide monomer units, wherein the rubber is natural rubber or a rubber mixture containing natural rubber and synthetic rubber; and the biomass content measured in accordance with ASTM D6866 is 20.0 to 50.0 wt %.

[0009] 2) The present invention can provide the thermoplastic resin composition according to 1) above, wherein the thermoplastic resin composition has a biomass content of 25.0 to 50.0% by weight as measured in accordance with ASTM D6866.

[0010] 3) The present invention can provide the thermoplastic resin composition according to 1) or 2), wherein the natural rubber is at least one selected from the group consisting of concentrated natural rubber, deproteinized natural rubber, crosslinked natural rubber, hydrogenated natural rubber, and epoxidized natural rubber.

[0011] 4) The present invention can provide a thermoplastic resin composition in any one of 1) to 3) above, wherein the rubber mixture contains 90.0 to 99.0 wt % of the natural rubber and 1.0 to 10.0 wt % of the synthetic rubber, based on the total weight of the rubber mixture.

[0012] 5) The present invention can provide a thermoplastic resin composition in any one of 1) to 4) above, wherein the synthetic rubber includes at least one selected from the group consisting of diene-based rubber polymers and acrylic-based rubber polymers.

[0013] 6) The present invention can provide a thermoplastic resin composition in any one of 1) to 5) above, wherein the thermoplastic resin composition contains 20.0 to 40.0% by weight of the rubber.

[0014] 7) The present invention can provide a thermoplastic resin composition in any one of 1) to 6), wherein the thermoplastic resin composition contains 35.0 to 68.0 wt % of the vinyl aromatic monomer unit.

[0015] 8) The present invention can provide a thermoplastic resin composition in any one of 1) to 7) above, wherein the thermoplastic resin composition contains 6.0 to 30.0 wt % of the vinyl cyanide-based monomer unit.

[0016] 9) The present invention can provide a thermoplastic resin composition in any one of 1) to 8) above, wherein the shell contains a (meth)acrylate monomer unit grafted to the rubber.

[0017] 10) The present invention can provide a thermoplastic resin composition in any one of the above 1) to 9), wherein the non-graft polymer contains a (meth)acrylate monomer unit. [Effects of the Invention]

[0018] The thermoplastic resin composition according to the present invention has excellent basic physical properties and a significant carbon reduction effect, and can be recognized as a bio-based plastic by countries around the world. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] In the present invention, the average particle size can be measured using a dynamic light scattering method, and specifically, it can mean the arithmetic average particle size in the particle size distribution measured by the dynamic light scattering method, that is, the scattering intensity average particle size.

[0021] In the present invention, the average particle size can be measured using a Nicomp 380 device manufactured by Particle Sizing Systems.

[0022] In the present invention, the natural rubber is not particularly limited as long as it is natural rubber collected from nature, but may be one or more selected from the group consisting of concentrated natural rubber, deproteinized natural rubber, crosslinked natural rubber, hydrogenated natural rubber, and epoxidized natural rubber. The natural rubber may be poly(cis-isoprene) collected from nature.

[0023] The concentrated natural rubber may refer to a product obtained by separating natural rubber from natural rubber latex by centrifugation and concentrating the separated natural rubber.

[0024] The deproteinized natural rubber may refer to natural rubber from which proteins have been removed.

[0025] The crosslinked natural rubber may refer to natural rubber crosslinked by vulcanization, peroxide crosslinking, photocrosslinking, or the like.

[0026] The hydrogenated natural rubber may refer to natural rubber in which the double bonds have been partially hydrogenated.

[0027] The epoxidized natural rubber may refer to natural rubber into which epoxy groups have been introduced, preferably natural rubber into which 10 to 50 mol % of epoxy groups have been introduced.

[0028] In the present invention, the diene rubber polymer may be a polymer produced by polymerizing, specifically, crosslinking, a diene monomer or a vinyl aromatic monomer with a diene monomer. The diene monomer may be one or more selected from the group consisting of 1,3-butadiene, isoprene, chloroprene, and piperylene, of which 1,3-butadiene is preferred. The vinyl aromatic monomer may be one or more selected from the group consisting of styrene, α-methylstyrene, α-ethylstyrene, and p-methylstyrene, of which styrene is preferred. The diene rubber polymer may be one or more selected from the group consisting of polybutadiene and styrene-butadiene copolymer.

[0029] In the present invention, the acrylic rubber polymer may be produced by polymerizing, specifically, crosslinking, a (meth)acrylate monomer. The (meth)acrylate monomer may include both acrylate and methacrylate monomers. The (meth)acrylate monomer may be at least one selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate, among which butyl acrylate is preferred.

[0030] In the present invention, the vinyl aromatic monomer unit may be a unit derived from a vinyl aromatic monomer, the types of which are as described above.

[0031] In the present invention, the vinyl cyanide-based monomer unit may be a unit derived from a vinyl cyanide-based monomer, and the vinyl cyanide-based monomer unit may be one or more selected from the group consisting of acrylonitrile, methacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile, among which acrylonitrile is preferred.

[0032] In the present invention, the (meth)acrylate monomer unit may be a unit derived from a (meth)acrylate monomer. The (meth)acrylate monomer may include both acrylate monomers and methacrylate monomers. Specific types of the (meth)acrylate monomer are as described above.

[0033] 1.Thermoplastic resin composition A thermoplastic resin composition according to one embodiment of the present invention comprises a graft polymer comprising a rubber and a shell comprising vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the rubber, and a non-graft polymer comprising vinyl aromatic monomer units and vinyl cyanide monomer units.

[0034] The thermoplastic resin composition may have a biomass content of 20.0 to 50.0 wt %, preferably 20.0 to 40.0 wt %, measured in accordance with ASTM D6866. If the above conditions are met, the thermoplastic resin composition can be recognized as a bio-based plastic by countries around the world. Furthermore, the impact strength of the thermoplastic resin composition can be further improved. If the above conditions are not met, the thermoplastic resin composition cannot be recognized as a bio-based plastic by countries around the world. If the above conditions are exceeded, the fluidity of the thermoplastic resin composition decreases, making it difficult to process.

[0035] The rubber is natural rubber; or a rubber mixture containing natural and synthetic rubber.

[0036] The synthetic rubber may be one or more selected from the group consisting of diene-based rubber polymers and acrylic-based rubber polymers.

[0037] The rubber mixture may contain 90.0 to 99.0% by weight of the natural rubber and 1.0 to 10.0% by weight of the synthetic rubber, based on the total weight of the rubber mixture, and preferably 90.0 to 95.0% by weight of the natural rubber and 5.0 to 10.0% by weight of the synthetic rubber. When the above conditions are satisfied, the impact strength of the thermoplastic resin composition can be further improved.

[0038] The thermoplastic resin composition can contain 20.0 to 40.0% by weight, preferably 20.0 to 35.0% by weight, of the rubber relative to the total weight of the thermoplastic resin composition. When the above conditions are satisfied, the processability of the thermoplastic resin composition can be improved.

[0039] The thermoplastic resin composition may contain 35.0 to 68.0 wt %, preferably 40.0 to 60.0 wt %, of the vinyl aromatic monomer units relative to the total weight of the thermoplastic resin composition. When the above conditions are satisfied, the processability of the thermoplastic resin composition can be improved. The content of the vinyl aromatic monomer units may be the sum of the contents of the vinyl aromatic monomer units contained in the graft polymer and the non-graft polymer, which are components of the thermoplastic resin composition.

[0040] The thermoplastic resin composition may contain 6.0 to 30.0 wt %, preferably 10.0 to 25.0 wt %, of the vinyl cyanide-based monomer units relative to the total weight of the thermoplastic resin composition. When the above conditions are satisfied, the impact strength and chemical resistance of the thermoplastic resin composition can be improved. The content of the vinyl cyanide-based monomer units may be the sum of the contents of the vinyl cyanide-based monomer units contained in the graft polymer and the non-graft polymer, which are components of the thermoplastic resin composition.

[0041] The thermoplastic resin composition may contain (meth)acrylate monomer units to improve colorability. The thermoplastic resin composition may contain 1.0 to 20.0 wt %, preferably 1.0 to 10.0 wt %, of the (meth)acrylate monomer units relative to the total weight of the thermoplastic resin composition. When the above conditions are satisfied, the strength and colorability of the thermoplastic resin composition can be improved. The content of the (meth)acrylate monomer units may be the sum of the contents of the (meth)acrylate monomer units contained in the graft polymer and non-graft polymer, which are components of the thermoplastic resin composition.

[0042] On the other hand, the graft polymer includes the rubber and a shell containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the rubber.

[0043] The graft polymer may contain 30.0 to 70.0% by weight of the rubber, preferably 35.0 to 65.0% by weight, and more preferably 40.0 to 60.0% by weight. When the above conditions are satisfied, the graft polymer can be easily produced and the cohesion properties can be improved.

[0044] The graft polymer may contain 20.0 to 60.0% by weight, preferably 25.0 to 55.0% by weight, and more preferably 30.0 to 50.0% by weight of the vinyl aromatic monomer unit. When the above conditions are satisfied, the processability of the graft polymer can be improved.

[0045] The graft polymer may contain 5.0 to 25.0% by weight, preferably 7.0 to 23.0% by weight, and more preferably 10.0 to 21.0% by weight of the vinyl cyanide monomer unit. When the above conditions are satisfied, the chemical resistance of the graft polymer can be improved.

[0046] In the graft polymer, the shell may contain (meth)acrylate monomer units grafted to the rubber to improve colorability.

[0047] The graft polymer may contain 30.0 to 70.0% by weight, preferably 35.0 to 65.0% by weight, of the rubber. When the above conditions are satisfied, the graft polymer can be easily produced and the cohesion properties can be improved.

[0048] The graft polymer can contain the vinyl aromatic monomer units in an amount of 18.0 to 60.0% by weight, preferably 20.0 to 50.0% by weight. When the above conditions are satisfied, the processability of the graft polymer can be improved.

[0049] The graft polymer can contain 4.5 to 28.0% by weight, preferably 6.0 to 20.0% by weight, of the vinyl cyanide monomer unit. When the above conditions are satisfied, the chemical resistance of the graft polymer can be improved.

[0050] The graft polymer may contain the (meth)acrylate monomer unit in an amount of 0.5 to 10.0% by weight, preferably 0.5 to 5.0% by weight. If the above conditions are met, the colorability of the graft polymer can be further improved.

[0051] The graft polymer may comprise a natural rubber and a shell comprising styrene units and acrylonitrile units grafted to the natural rubber.

[0052] The graft polymer may comprise a rubber mixture containing natural rubber and a diene-based rubbery polymer, and a shell containing styrene units and acrylonitrile units grafted onto the rubber mixture.

[0053] On the other hand, the non-grafted polymer contains vinyl aromatic monomer units and vinyl cyanide monomer units.

[0054] The non-graft polymer may contain 50 to 90% by weight, preferably 65 to 85% by weight, more preferably 70 to 80% by weight of the vinyl aromatic monomer unit. When the above conditions are satisfied, the processability of the non-graft polymer can be improved.

[0055] The non-graft polymer can contain the vinyl cyanide monomer unit in an amount of 10.0 to 50.0% by weight, preferably 15.0 to 35.0% by weight, and more preferably 20.0 to 30.0% by weight. When the above conditions are satisfied, the chemical resistance of the non-graft polymer can be improved.

[0056] The non-grafted polymer may contain (meth)acrylate monomer units to improve colorability.

[0057] The non-graft polymer can contain the vinyl aromatic monomer units in an amount of 60 to 80% by weight, preferably 65 to 75% by weight. When the above conditions are satisfied, the processability of the non-graft polymer can be improved.

[0058] The non-graft polymer can contain the vinyl cyanide monomer unit in an amount of 10.0 to 30.0% by weight, preferably 15.0 to 25.0% by weight. When the above conditions are satisfied, the chemical resistance of the non-graft polymer can be improved.

[0059] The non-graft polymer can contain the (meth)acrylate monomer unit in an amount of 1.0 to 20.0% by weight, preferably 5.0 to 15.0% by weight. When the above conditions are satisfied, the colorability of the non-graft polymer can be further improved.

[0060] The non-graft polymer may be a binary copolymer consisting of the vinyl aromatic monomer unit and the vinyl cyanide monomer unit, or a ternary copolymer consisting of the vinyl aromatic monomer unit, the vinyl cyanide monomer unit, and the (meth)acrylate monomer unit, specifically a styrene / acrylonitrile polymer or a styrene / acrylonitrile / methyl methacrylate polymer.

[0061] The thermoplastic resin composition can contain the graft polymer in an amount of 30.0 to 95.0% by weight, preferably 35.0 to 93.0% by weight, and more preferably 40.0 to 90.0% by weight. When the above conditions are satisfied, the impact resistance of the thermoplastic resin composition can be improved.

[0062] The thermoplastic resin composition can contain the non-grafted polymer in an amount of 5.0 to 70.0% by weight, preferably 7.0 to 65.0% by weight, and more preferably 10.0 to 60.0% by weight. When the above conditions are satisfied, the processability and chemical resistance of the thermoplastic resin composition can be improved.

[0063] The thermoplastic resin composition may contain, as an additive, one or more selected from the group consisting of natural rosin soap and ethylene bisstearamide.

[0064] 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. [Example]

[0065] Manufacturing Example 1 A mixture was prepared containing 37.0 parts by weight of styrene (S), 13.0 parts by weight of acrylonitrile (AN), 0.3 parts by weight of tertiary dodecyl mercaptan, 0.3 parts by weight of sodium oleate, 0.3 parts by weight of tertiary butyl hydroperoxide, 0.014 parts by weight of iron (II) sulfate, 0.700 parts by weight of tetrasodium pyrophosphate, 1.500 parts by weight of dextrose, and 50.0 parts by weight of distilled water.

[0066] A reactor was charged with 50.0 parts by weight of deproteinized natural rubber (Selatex 3821 manufactured by Sumitomo Rubber Co., Ltd.), 2.0 parts by weight of sodium dodecyl sulfate, 0.5 parts by weight of cumene hydroperoxide, 0.006 parts by weight of iron (II) sulfate, 0.300 parts by weight of tetrasodium pyrophosphate, 0.700 parts by weight of dextrose, and 100.0 parts by weight of distilled water, and the mixture was reacted at 70°C for 5 hours.

[0067] The mixture was then continuously added to the reactor (internal temperature: 70°C) at a constant rate for 4 hours to react, and then aged for 1 hour, after which the reaction was terminated to produce a graft polymer latex.

[0068] The graft polymer latex was coagulated with 2.0 parts by weight of calcium carbonate, washed, dehydrated and dried to prepare a graft polymer powder.

[0069] Manufacturing Example 2 A mixture was prepared containing 37.0 parts by weight of styrene (S), 13.0 parts by weight of acrylonitrile (AN), 0.3 parts by weight of sodium oleate, 0.3 parts by weight of tertiary dodecyl mercaptan, 0.3 parts by weight of tertiary butyl hydroperoxide, 0.014 parts by weight of iron (II) sulfate, 0.700 parts by weight of tetrasodium pyrophosphate, 1.500 parts by weight of dextrose, and 50.0 parts by weight of distilled water.

[0070] 50.0 parts by weight of deproteinized natural rubber (Selatex 3821 manufactured by Sumitomo Rubber Co., Ltd.), 2.0 parts by weight of sodium dodecyl sulfate, and 100.0 parts by weight of distilled water were charged into a reactor, and the internal temperature of the reactor was raised to 70°C.

[0071] The mixture was then continuously added to the reactor (internal temperature: 70°C) at a constant rate for 4 hours to react, and then aged for 1 hour, after which the reaction was terminated to produce a graft polymer latex.

[0072] The graft polymer latex was coagulated with 2.0 parts by weight of calcium carbonate, washed, dehydrated and dried to prepare a graft polymer powder.

[0073] Manufacturing Example 3 A mixture was prepared containing 37.0 parts by weight of styrene (S), 13.0 parts by weight of acrylonitrile (AN), 0.3 parts by weight of sodium oleate, 0.3 parts by weight of tertiary dodecyl mercaptan, 0.3 parts by weight of tertiary butyl hydroperoxide, 0.014 parts by weight of iron (II) sulfate, 0.700 parts by weight of tetrasodium pyrophosphate, 1.500 parts by weight of dextrose, and 50.0 parts by weight of distilled water.

[0074] 50.0 parts by weight (based on solids) of polybutadiene rubber (PBR, average particle size: 300.0 nm) latex, 2.0 parts by weight of sodium dodecyl sulfate, and 100.0 parts by weight of distilled water were added to a reactor and kneaded, and the internal temperature of the reactor was raised to 70°C.

[0075] The mixture was then continuously added to the reactor (internal temperature: 70°C) at a constant rate for 4 hours to react, and then aged for 1 hour, after which the reaction was terminated to produce a graft polymer latex.

[0076] The graft polymer latex was coagulated with 2.0 parts by weight of calcium carbonate, washed, dehydrated and dried to prepare a graft polymer powder.

[0077] Manufacturing Example 4 A mixture was prepared containing 37.0 parts by weight of styrene (S), 13.0 parts by weight of acrylonitrile (AN), 0.3 parts by weight of sodium oleate, 0.3 parts by weight of tertiary dodecyl mercaptan, 0.3 parts by weight of tertiary butyl hydroperoxide, 0.014 parts by weight of iron (II) sulfate, 0.700 parts by weight of tetrasodium pyrophosphate, 1.500 parts by weight of dextrose, and 50.0 parts by weight of distilled water.

[0078] 25.0 parts by weight of crosslinked natural rubber (Thaitex Prevulcanized NR MM Grade), 25.0 parts by weight (solids basis) of polybutadiene rubber (PBR) latex (average particle size: 300 nm), 2.0 parts by weight of sodium dodecyl sulfate, and 100.0 parts by weight of distilled water were added to a reactor and kneaded, and the temperature of the reactor was raised to 70°C.

[0079] The mixture was then continuously added to the reactor (internal temperature: 70°C) at a constant rate for 4 hours to react, and then aged for 1 hour, after which the reaction was terminated to produce a graft polymer latex.

[0080] The graft polymer latex was coagulated with 2.0 parts by weight of calcium carbonate, washed, dehydrated and dried to prepare a graft polymer powder.

[0081] Production Example 5 A mixture was prepared containing 37.0 parts by weight of styrene (S), 13.0 parts by weight of acrylonitrile (AN), 0.3 parts by weight of sodium oleate, 0.3 parts by weight of tertiary dodecyl mercaptan, 0.3 parts by weight of tertiary butyl hydroperoxide, 0.014 parts by weight of iron (II) sulfate, 0.700 parts by weight of tetrasodium pyrophosphate, 1.500 parts by weight of dextrose, and 50.0 parts by weight of distilled water.

[0082] 46.0 parts by weight of crosslinked natural rubber (Thaitex Prevulcanized NR MM Grade), 4.0 parts by weight (solids basis) of polybutadiene rubber (PBR, average particle size: 300.0 nm) latex, 2.0 parts by weight of sodium dodecyl sulfate, and 100.0 parts by weight of distilled water were added to a reactor and kneaded, and then the internal temperature of the reactor was raised to 70°C.

[0083] The mixture was then continuously added to the reactor (internal temperature: 70°C) at a constant rate for 4 hours to react, and then aged for 1 hour, after which the reaction was terminated to produce a graft polymer latex.

[0084] The graft polymer latex was coagulated with 2.0 parts by weight of calcium carbonate, washed, dehydrated and dried to prepare a graft polymer powder.

[0085] Manufacturing Example 6 A mixture containing 75.0 parts by weight of styrene (S), 25.0 parts by weight of acrylonitrile (AN), 30.0 parts by weight of toluene, and 0.1 parts by weight of tertiary dodecyl mercaptan was continuously added to a reactor (internal temperature: 148°C) and reacted for an average reaction time of 3 hours. The polymerization solution discharged from the reactor was heated in a preheating tank, and unreacted monomer was evaporated in a vaporization tank, followed by production of non-grafted polymer pellets using a polymer transfer pump extruder.

[0086] Manufacturing Example 7 A mixture containing 70.0 parts by weight of styrene (S), 20.0 parts by weight of acrylonitrile (AN), 10.0 parts by weight of methyl methacrylate, 30.0 parts by weight of toluene, and 0.1 parts by weight of tertiary dodecyl mercaptan was continuously added to a reactor (internal temperature: 148°C) and reacted for an average reaction time of 3 hours. The polymerization solution discharged from the reactor was heated in a preheating tank, and unreacted monomer was evaporated in a vaporization tank, followed by production of non-grafted polymer pellets using a polymer transfer pump extruder.

[0087] Examples and Comparative Examples The components used in the following examples and comparative examples are described below.

[0088] 1) Graft polymer (1) Production Example 1: The graft polymer produced in Production Example 1 was used. (2) Production Example 2: The graft polymer produced in Production Example 2 was used. (3) Production Example 3: The graft polymer produced in Production Example 3 was used. (4) Production Example 4: The graft polymer produced in Production Example 4 was used. (4) Production Example 5: The graft polymer produced in Production Example 5 was used.

[0089] 2) Non-graft polymer (1) Production Example 6: The non-grafted polymer produced in Production Example 6 was used. (2) Production Example 7: The non-grafted polymer produced in Production Example 7 was used.

[0090] The above-mentioned components in the amounts shown in Tables 1 to 3 below were mixed with 0.3 parts by weight of a lubricant (ethylene bisstearamide), 0.2 parts by weight of an antioxidant (IRGANOX1076 manufactured by BASF), and 0.2 parts by weight of an antioxidant 2 (IRGAFOS168 manufactured by BASF) to produce a thermoplastic resin composition.

[0091] Experimental Example 1 The thermoplastic resin compositions of the Examples and Comparative Examples were extruded to produce pellets. These pellets were then injected to produce test pieces. The physical properties of these test pieces were evaluated by the following methods, and the results are shown in Tables 1 to 3 below.

[0092] 1) Content (wt%) of components of thermoplastic resin composition: The content (wt%) of the components was calculated based on the content (parts by weight) of natural rubber, polybutadiene rubber (PBR), styrene units (S units), and acrylonitrile units (AN units) added during the production of the graft copolymer and non-graft copolymer contained in the thermoplastic resin composition.

[0093] 2) Biomass content (wt%) in thermoplastic resin composition: The biomass content was measured in accordance with ASTM D6866.

[0094] 3) Melt Flow Index (g / 10 min): Measured in accordance with ASTM D1238 at 220°C and 10 kg.

[0095] 4) Impact strength (kgf·cm / cm): The notched Izod impact strength of the test piece (1 / 4 inch) was measured in accordance with ASTM D256.

[0096] [Table 1]

[0097] [Table 2]

[0098] [Table 3]

[0099] Referring to Tables 1 to 3, Examples 1 to 7, which have a biomass content of 20.1 to 45.8 wt% measured in accordance with ASTM D6866, are not only excellent in basic physical properties such as flow index and impact strength, but are also recognized as bio-based plastics by countries around the world. However, Comparative Examples 1 to 3, which have a biomass content of less than 20.0 wt% measured in accordance with ASTM D6866, are not recognized as bio-based plastics by countries around the world.

[0100] Furthermore, Comparative Example 4, which had a biomass content of 51.0% by weight as measured in accordance with ASTM D6866, is recognized as a bio-based plastic by countries around the world, but its fluidity was too low to be processed, making it impossible to produce test specimens.

Claims

1. a graft polymer including a rubber and a shell including vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the rubber, and a non-graft polymer including vinyl aromatic monomer units and vinyl cyanide monomer units; the rubber is natural rubber; or a rubber mixture containing natural rubber and synthetic rubber; A thermoplastic resin composition having a biomass content of 20.0 to 50.0% by weight as measured in accordance with ASTM D6866.

2. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has a biomass content of 25.0 to 50.0% by weight as measured in accordance with ASTM D6866.

3. 2. The thermoplastic resin composition according to claim 1, wherein the natural rubber is at least one selected from the group consisting of concentrated natural rubber, deproteinized natural rubber, crosslinked natural rubber, hydrogenated natural rubber, and epoxidized natural rubber.

4. 2. The thermoplastic resin composition according to claim 1, wherein the rubber mixture contains 90.0 to 99.0% by weight of the natural rubber and 1.0 to 10.0% by weight of the synthetic rubber, based on the total weight of the rubber mixture.

5. The thermoplastic resin composition according to claim 1 , wherein the synthetic rubber comprises at least one selected from the group consisting of diene-based rubber polymers and acrylic-based rubber polymers.

6. The thermoplastic resin composition according to claim 1, comprising 20.0 to 40.0% by weight of said rubber.

7. 2. The thermoplastic resin composition according to claim 1, comprising 35.0 to 68.0% by weight of the vinyl aromatic monomer units.

8. 2. The thermoplastic resin composition according to claim 1, comprising 6.0 to 30.0% by weight of the vinyl cyanide monomer unit.

9. The thermoplastic resin composition according to claim 1 , wherein the shell comprises (meth)acrylate monomer units grafted to the rubber.

10. The thermoplastic resin composition according to claim 1 , wherein the non-grafted polymer contains a (meth)acrylate monomer unit.

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