Thermoplastic resin composition

Abstract

The present invention relates to a thermoplastic resin composition comprising: a grafted polymer comprising a rubber polymer having a gel content of 0 to 10% by weight and comprising an aromatic vinyl monomer unit and a diene monomer unit, and a shell comprising a (meth)acrylate monomer unit and an aromatic vinyl monomer unit grafted to the rubber polymer; and a non-grafted polymer comprising 90% by weight or more of a (meth)acrylate monomer unit.

Description

[0001] [Cross-references to related applications]

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2021-0098177, filed on July 26, 2021, and Korean Patent Application No. 10-2022-0088170, filed on July 18, 2022, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] This invention relates to a thermoplastic resin composition, and more specifically, to a thermoplastic resin composition that can achieve excellent impact resistance, scratch resistance, matte finish, and processability. Background Technology

[0004] Diene rubber polymers are widely used as impact modifiers for various thermoplastic polymers, such as graft polymers, due to their excellent rubber properties. Graft polymers can be widely used in materials for electrical products, electronic products, automotive parts, and general office supplies, and can be prepared by graft polymerization of aromatic vinyl monomers and vinyl cyanide monomers with diene rubber polymers.

[0005] Meanwhile, since the gel content of diene rubber polymers affects the impact resistance of grafted polymers, an excessive amount of molecular weight regulator is needed to adjust the gel content. However, when an excessive amount of molecular weight regulator is used, the polymerization rate decreases and the polymerization time increases, thus reducing the preparation efficiency.

[0006] Furthermore, in recent years, with industrial development and the diversification of lifestyles, there is a need to inject high functionality into complex structures while simultaneously endowing them with properties such as matte finish. However, grafted polymers using diene-based rubber polymers struggle to achieve both excellent matte finish and processability simultaneously. Additionally, embossing techniques using molds to achieve matte finishes have been proposed, but a limitation is that conventional molds cannot achieve this. Furthermore, the use of matting agents to achieve matte finishes has been suggested, but this presents problems such as increased manufacturing costs, deterioration of basic properties, and unsatisfactory matte finish characteristics.

[0007] Therefore, a method has been studied to improve impact resistance, as well as matte properties, scratch resistance, processability and preparation efficiency by adjusting the gel content.

[0008] [Related Technical Documents]

[0009] [Patent Literature]

[0010] (Patent Document 1) JP1995-025975B Summary of the Invention

[0011] Technical issues

[0012] The present invention aims to provide a thermoplastic resin composition that can achieve excellent impact resistance, scratch resistance, matte finish and processability.

[0013] Technical solution

[0014] 1) One aspect of the present invention provides a thermoplastic resin composition comprising: a grafted polymer comprising a rubber polymer having a gel content of 0% to 10% by weight and comprising aromatic vinyl monomer units and diene monomer units, and a shell comprising (meth)acrylate monomer units and aromatic vinyl monomer units grafted to said rubber polymer; and a non-grafted polymer comprising more than 90% by weight of (meth)acrylate monomer units.

[0015] 2) According to 1), the present invention provides a thermoplastic resin composition wherein the gel content of the rubber polymer is from 0% by weight to 5% by weight.

[0016] 3) According to 1) or 2), the present invention provides a thermoplastic resin composition, wherein the rubber polymer comprises aromatic vinyl monomer units and diene monomer units in a weight ratio of 10:90 to 35:65.

[0017] 4) According to any one of 1) to 3), the present invention provides a thermoplastic resin composition wherein the average particle size of the rubber polymer is 20 nm to 100 nm.

[0018] 5) According to any one of 1) to 4), the present invention provides a thermoplastic resin composition, wherein the graft polymer comprises: 30.0% to 65.0% by weight of the rubber polymer; 10.0% to 55.0% by weight of the (meth)acrylate monomer unit; and 5.0% to 40.0% by weight of the aromatic vinyl monomer unit.

[0019] 6) According to any one of 1) to 5), the present invention provides a thermoplastic resin composition, wherein the ungrafted polymer comprises one or more selected from (meth)acrylic monomer units and aromatic vinyl monomer units.

[0020] 7) According to any one of 1) to 6), the present invention provides a thermoplastic resin composition comprising: 10.0% to 50.0% by weight of the grafted polymer; and 50.0% to 90.0% by weight of the ungrafted polymer.

[0021] 8) According to any one of 1) to 7), the present invention provides a thermoplastic resin composition wherein the shell of the grafted polymer comprises vinyl cyanide monomer units grafted to the rubber polymer.

[0022] 9) According to any one of 1) to 8), the present invention provides a thermoplastic resin composition comprising: 5.0% to 25.0% by weight of the rubber polymer; 60.0% to 90.0% by weight of the (meth)acrylate monomer unit; and 3.0% to 20.0% by weight of the aromatic vinyl monomer unit.

[0023] Beneficial effects

[0024] The thermoplastic resin composition according to the present invention can achieve excellent impact resistance, scratch resistance, matte finish and processability. Detailed Implementation

[0025] The terms and words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and based on the principle that inventors can appropriately define the concepts of terms in order to best describe their inventions, the terms and words should be understood as having meanings and concepts consistent with the technical concept of the present invention.

[0026] In this invention, the gel content is calculated as follows. The rubber polymer latex is coagulated with a dilute acid or metal salt, washed, and dried in a vacuum oven at 60°C for 24 hours to obtain a rubber block. The rubber block is cut with scissors to prepare a 1g rubber fragment. The rubber fragment is placed in 100g of toluene and stored in a dark room at 23°C for 48 hours to separate the sol and gel. The weights of the sol and gel are substituted into the following equation to calculate the gel content. In this case, although there is no particular limitation on the type of dilute acid, it is preferred to use one or more selected from hydrochloric acid, sulfuric acid, formic acid, etc. Furthermore, although there is no particular limitation on the type of metal salt, it is preferred to use one or more selected from magnesium sulfate, calcium chloride, aluminum sulfate, etc.

[0027] Gel content (wt%) = weight of gel / weight of rubber segment × 100

[0028] In this invention, refractive index refers to the absolute refractive index of a material and is considered to be the ratio of the velocity of electromagnetic radiation in free space to the velocity of radiation within the material. The radiation can be visible light with wavelengths from 450 nm to 680 nm, specifically visible light with a wavelength of 589.3 nm. The refractive index can be measured using known methods, namely, by using an Abbe refractometer.

[0029] In this invention, after the grafted and ungrafted polymers are spread to a thickness of 0.2 mm, the refractive index can be measured at 25°C using an Abbe refractometer with visible light at a wavelength of 589.3 nm.

[0030] In this invention, the average particle size can be measured using dynamic light scattering, specifically by using a Nicomp 380 instrument (commercially available from Particle Sizing Systems). In this invention, the average particle size can refer to the arithmetic mean particle size of the particle size distribution measured by dynamic light scattering, i.e., the average particle size based on the scattering intensity distribution.

[0031] In this invention, the average particle size can be measured using a transmission electron microscope (TEM).

[0032] In this invention, the weight of the rubber polymer, diene monomer units, (meth)acrylate monomer units, aromatic vinyl monomer units, and vinyl cyanide monomer units contained in the thermoplastic resin composition can be measured by infrared (IR) spectroscopy. In this case, Nicolet can be used. TM The iS20 FTIR spectrometer (commercially available from ThermoScientific) can be used as an IR spectrometer.

[0033] In this invention, polymerization conversion rate refers to the degree to which monomers polymerize to form polymers, and can be calculated using the following equation.

[0034] Polymerization conversion (%) = {(Total weight of monomers added until polymerization terminates) - (Total weight of unreacted monomers at the time of polymerization conversion measurement)} / (Total weight of monomers added until polymerization terminates) × 100

[0035] In this invention, the diene monomer unit can be a unit derived from a diene monomer. The diene monomer can be one or more selected from 1,3-butadiene, isoprene, chloroprene, and isoprene, preferably 1,3-butadiene.

[0036] In this invention, the aromatic vinyl monomer unit can be a unit derived from an aromatic vinyl monomer. The aromatic vinyl monomer can be one or more selected from styrene, α-methylstyrene, α-ethylstyrene, and p-methylstyrene, preferably styrene.

[0037] In this invention, the (meth)acrylate monomer unit can be a unit derived from a (meth)acrylate monomer. The term (meth)acrylate monomer can be a term encompassing both acrylate monomers and methacrylate monomers. The (meth)acrylate monomer can be (meth)acrylate C1 to C12. 10Alkyl ester monomers, and the (meth)acrylic acid C1 to C1... 10 The alkyl ester monomer may be one or more selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, heptyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate and decyl methacrylate, with methyl methacrylate being preferred.

[0038] In this invention, the vinyl cyanide monomer unit can be a unit derived from a vinyl cyanide monomer. The vinyl cyanide monomer can be one or more selected from acrylonitrile, methacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile, preferably acrylonitrile.

[0039] In this invention, the (meth)acrylic acid monomer unit may be one or more selected from acrylic acid and methacrylic acid.

[0040] In this invention, the emulsifier may be one or more selected from sodium dicyclohexyl sulfosuccinate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium octadecyl sulfate, sodium oleyl sulfate, potassium dodecyl sulfate, potassium octadecyl sulfate, potassium oleate, sodium oleate, potassium rosinate, and sodium rosinate. Among the substances listed above, one or more selected from potassium oleate, sodium oleate, and potassium rosinate are preferred.

[0041] In this invention, the initiator may be one or more selected from potassium persulfate, sodium persulfate, ammonium persulfate, cumene hydroperoxide, dicumene hydroperoxide, azobisisobutyronitrile, tert-butyl hydroperoxide, p-menthane hydroperoxide, benzoyl peroxide, and 1,1-bis(tert-butylperoxy)cyclohexane. Among the substances listed above, one or more selected from potassium persulfate, cumene hydroperoxide, and 1,1-bis(tert-butylperoxy)cyclohexane are preferred.

[0042] In this invention, the molecular weight regulator may be one or more selected from α-methylstyrene dimer, tert-dodecyl mercaptan, n-dodecyl mercaptan, tert-octyl mercaptan, n-octyl mercaptan, carbon tetrachloride, dichloromethane, dibromomethane, tetraethylthiuram disulfide, dipentylthiuram disulfide, and diisopropyl xanthate disulfide. Among the substances listed above, tert-dodecyl mercaptan is preferred.

[0043] In this invention, the redox catalyst may be one or more selected from sodium formaldehyde sulfoxylate, sodium ethylenediaminetetraacetate, ferrous sulfate, glucose, tetrasodium pyrophosphate, anhydrous sodium pyrophosphate, and sodium sulfate. Among the substances listed above, one or more selected from ferrous sulfate, glucose, and tetrasodium pyrophosphate are preferred.

[0044] In this invention, the aqueous solvent can be ion-exchanged water or deionized water.

[0045] 1. Thermoplastic resin composition

[0046] According to one aspect of the invention, a thermoplastic resin composition comprises: a grafted polymer comprising a rubber polymer having a gel content of 0% to 10% by weight and comprising aromatic vinyl monomer units and diene monomer units, and a shell comprising (meth)acrylate monomer units and aromatic vinyl monomer units grafted to said rubber polymer; and a non-grafted polymer comprising more than 90% by weight of (meth)acrylate monomer units.

[0047] The refractive indices of the grafted polymer and the ungrafted polymer included in the thermoplastic resin composition according to the present invention can differ by 0.0350 or more, preferably 0.0400 or more. When the above conditions are met, the thermoplastic resin composition can be opaque.

[0048] The thermoplastic resin composition according to the invention may comprise 10.0 wt% to 50.0 wt% of a grafted polymer and 50.0 wt% to 90.0 wt% of a non-grafted polymer, preferably 15.0 wt% to 45.0 wt% of a grafted polymer and 55.0 wt% to 85.0 wt% of a non-grafted polymer, more preferably 15.0 wt% to 35.0 wt% of a grafted polymer and 65.0 wt% to 85.0 wt% of a non-grafted polymer. When the above conditions are met, the thermoplastic resin composition can achieve excellent impact resistance and processability.

[0049] The thermoplastic resin composition according to the invention may contain 5.0% to 25.0% by weight, preferably 10.0% to 20.0% by weight, of a rubber polymer. When the above conditions are met, the thermoplastic resin composition can achieve excellent impact resistance.

[0050] The thermoplastic resin composition according to the invention may contain 60.0% to 90.0% by weight, preferably 65.0% to 85.0% by weight, of (meth)acrylate monomer units. When the above conditions are met, the thermoplastic resin composition can achieve excellent impact resistance and abrasion resistance.

[0051] Furthermore, the thermoplastic resin composition according to the present invention may contain 3.0% to 20.0% by weight, preferably 8.0% to 15.0% by weight, of aromatic vinyl monomer units. When the above conditions are met, the thermoplastic resin composition can achieve excellent processing properties.

[0052] Furthermore, the thermoplastic resin composition according to the present invention may contain vinyl cyanide monomer units. In this case, the content of vinyl cyanide monomer units may be 10.0% by weight or less, preferably 5% by weight or less. When the above conditions are met, excellent chemical resistance can be achieved while minimizing yellowing.

[0053] The grafted polymers and ungrafted polymers that are components of the present invention will be described in detail below.

[0054] 1) Grafted polymers

[0055] The grafted polymer comprises: a rubber polymer having a gel content of 0% to 10% by weight and containing aromatic vinyl monomer units and diene monomer units; and a shell comprising (meth)acrylate monomer units and aromatic vinyl monomer units grafted onto the rubber polymer. Furthermore, the shell may contain (meth)acrylate monomer units and aromatic vinyl monomer units not grafted onto the rubber polymer. To improve the chemical resistance of the grafted polymer, the shell may also contain vinyl cyanide monomer units grafted onto or not grafted onto the rubber polymer.

[0056] The gel content of the rubber polymer can be from 0% to 10% by weight, preferably from 0% to 5% by weight, and more preferably from 0% to 1% by weight. When the above range is met, the thermoplastic resin composition can achieve excellent matte properties and impact resistance. However, when the range is greater than the above range, the thermoplastic resin composition cannot achieve matte properties, and the impact resistance will be significantly degraded.

[0057] Meanwhile, the gel content of the rubber polymer can be adjusted by the polymerization temperature and the final polymerization conversion rate. Furthermore, a rubber polymer meeting the above gel content can be prepared by initiating and carrying out the polymerization of aromatic vinyl monomer units and diene monomer units at 0°C to 20°C, and terminating the polymerization when the polymerization conversion rate reaches 40% to 60%. Preferably, a rubber polymer meeting the above gel content can be prepared by initiating and carrying out the polymerization of aromatic vinyl monomer units and diene monomer units at 5°C to 15°C, and terminating the polymerization when the polymerization conversion rate reaches 45% to 55%.

[0058] If either the polymerization temperature or the polymerization termination time is not met, it will be difficult to prepare a rubber polymer that meets the required gel content.

[0059] The polymerization can be emulsion polymerization, and can be carried out in the presence of one or more selected from emulsifiers, initiators, molecular weight regulators, redox catalysts and aqueous solvents.

[0060] The amount of emulsifier can be from 1.0 to 10.0 parts by weight, preferably from 3.0 to 7.0 parts by weight, relative to 100 parts by weight of all monomers added in the preparation of the rubber polymer. When the above conditions are met, polymerization stability and latex stability can be improved, and can be adjusted so that the rubber polymer has a desired average particle size.

[0061] The amount of initiator can be 0.1 to 0.5 parts by weight, preferably 0.1 to 0.3 parts by weight, relative to 100 parts by weight of all monomers added in the preparation of the rubber polymer. When the above conditions are met, emulsion polymerization can be stably initiated and carried out.

[0062] The amount of molecular weight regulator can be 0.1 to 1.7 parts by weight, preferably 0.3 to 1.5 parts by weight, and more preferably 0.5 to 1.3 parts by weight, relative to 100 parts by weight of all monomers added in the preparation of the rubber polymer. When the above conditions are met, the gel content of the rubber polymer can be finely adjusted. When the content of the molecular weight regulator increases, the gel content decreases, and when the content of the molecular weight regulator decreases, the gel content increases.

[0063] The amount of redox catalyst can be from 0.010 parts by weight to 0.100 parts by weight, preferably from 0.030 parts by weight to 0.080 parts by weight, relative to 100 parts by weight of all monomers added in the preparation of the rubber polymer.

[0064] Meanwhile, when the rubber polymer contains only diene monomer units, an excess of (meth)acrylate monomer units is required in the matrix portion to prevent or minimize the difference in refractive index between the impact-modified portion and the matrix portion of the thermoplastic resin composition. However, (meth)acrylate monomer units reduce the chemical resistance of the thermoplastic resin composition and increase manufacturing costs due to the high unit cost of (meth)acrylate monomers. Furthermore, rubber polymers cannot be prepared using only aromatic vinyl monomers.

[0065] However, since the rubber polymer contains not only diene monomer units but also aromatic vinyl monomer units, the refractive index of the rubber polymer can be increased, and therefore, a small amount of (meth)acrylate monomer units can be included in the matrix portion. Therefore, the thermoplastic resin composition according to the invention can minimize the reduction in chemical resistance and the increase in manufacturing costs caused by (meth)acrylate monomer units.

[0066] The rubber polymer may contain aromatic vinyl monomer units and diene monomer units in a weight ratio of 10:90 to 35:65, preferably 15:85 to 30:70. When the above conditions are met, impact resistance can be improved and the refractive index can be increased, thereby reducing the amount of (meth)acrylate monomer units and minimizing the reduction in chemical resistance and increase in manufacturing costs caused by (meth)acrylate monomer units.

[0067] The rubber polymer, by comprising diene monomer units and aromatic vinyl monomer units in the aforementioned weight ratio, can have a higher refractive index than a rubber polymer comprising only diene monomers. As a specific example, the refractive index of the rubber polymer can be from 1.5230 to 1.5420, preferably from 1.5300 to 1.5400.

[0068] The average particle size of the rubber polymer can be from 20 nm to 100 nm, preferably from 20 nm to 80 nm. When the above range is met, excellent matte properties and impact resistance can be achieved.

[0069] The grafted polymer may contain 30.0% to 65.0% by weight, preferably 35.0% to 60.0% by weight, of a rubber polymer. When the above range is met, excellent impact resistance can be achieved.

[0070] The graft polymer may contain 10.0% to 55.0% by weight, preferably 15.0% to 50.0% by weight, of (meth)acrylate monomer units. When the above range is met, excellent scratch resistance can be achieved.

[0071] The graft polymer may contain 5.0% to 40.0% by weight, preferably 10.0% to 35.0% by weight, of aromatic vinyl monomer units. When the above range is met, excellent processing properties can be achieved.

[0072] The grafted polymer may further contain vinyl cyanide monomer units, and the content of vinyl cyanide monomer units may be less than 7.0% by weight to achieve excellent chemical resistance and minimize yellowing. In this case, the content of vinyl cyanide monomer units may refer to the content of vinyl cyanide monomer units grafted with or not grafted with the rubber polymer.

[0073] The refractive index of the grafted polymer can be from 1.5230 to 1.5420, preferably from 1.5300 to 1.5400. When the above range is met, the refractive index is the same as or similar to that of the rubber polymer, thereby improving the transparency of the grafted polymer.

[0074] 2) Non-grafted polymers

[0075] The ungrafted polymer contains more than 90% by weight of (meth)acrylate monomer units. When the content of (meth)acrylate monomer units is less than the above range, the scratch resistance and matte finish of the thermoplastic resin composition deteriorate.

[0076] To improve scratch resistance, the ungrafted polymer may further comprise one or more comonomers selected from (meth)acrylic acid monomer units and aromatic vinyl monomer units. The comonomers may be included as a remainder, such that the monomer content in the ungrafted polymer is 100% by weight.

[0077] The refractive index of the ungrafted polymer can be from 1.4800 to 1.5000, preferably from 1.4850 to 1.4950.

[0078] The present invention will now be described in detail with reference to embodiments so that those skilled in the art can readily implement it. However, the present invention may be implemented in several different forms and is therefore not limited to the embodiments described herein.

[0079] Preparation Example 1

[0080] <Preparation of Rubber Polymers>

[0081] 200 parts by weight of deionized water, 20 parts by weight of styrene, 80 parts by weight of 1,3-butadiene, 2.0 parts by weight of potassium oleate, 3.0 parts by weight of potassium rosinate, 0.1 parts by weight of cumene hydroperoxide, 1.0 part by weight of tert-dodecyl mercaptan, 0.010 parts by weight of sodium pyrophosphate, 0.050 parts by weight of glucose, and 0.001 parts by weight of ferrous sulfate were added in batches to a nitrogen-purified polymerization reactor (autoclave) and polymerized at 10°C. When the polymerization conversion reached 50%, the polymerization was terminated to prepare a styrene / butadiene rubber polymer latex (gel content: 0 wt%, average particle size: 40 nm, refractive index: 1.5310).

[0082] <Preparation of Grafted Polymers>

[0083] A liquid mixture comprising 200 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 29.6 parts by weight of methyl methacrylate, 20.4 parts by weight of styrene, 0.6 parts by weight of tert-dodecyl mercaptan, 0.050 parts by weight of ethylenediaminetetraacetic acid, 0.100 parts by weight of sodium formaldehyde sulfoxylate, 0.001 parts by weight of ferrous sulfate and 0.2 parts by weight of cumene hydroperoxide was prepared.

[0084] Fifty parts by weight (based on solids content) of styrene / butadiene rubber polymer latex were added to a reactor. Polymerization was then carried out simultaneously with the continuous addition of the liquid mixture to the reactor at 60°C for 5 hours. After the continuous addition of the liquid mixture was completed, aging was performed at 60°C for 1 hour, and polymerization was terminated to prepare the grafted polymer latex. The entire amount of the grafted polymer latex was added to an aqueous solution containing 2 parts by weight of calcium chloride, and the mixture was coagulated, aged, washed, dehydrated, and dried to prepare a grafted polymer powder (refractive index: 1.5310).

[0085] Preparation Example 2

[0086] <Preparation of Rubber Polymers>

[0087] 200 parts by weight of deionized water, 25 parts by weight of styrene, 75 parts by weight of 1,3-butadiene, 3.0 parts by weight of potassium oleate, 3.0 parts by weight of potassium rosinate, 0.1 parts by weight of cumene hydroperoxide, 0.8 parts by weight of tert-dodecyl mercaptan, 0.010 parts by weight of sodium pyrophosphate, 0.050 parts by weight of glucose, and 0.001 parts by weight of ferrous sulfate were added in batches to a nitrogen-purified polymerization reactor (autoclave) and polymerized at 10°C. When the polymerization conversion reached 60%, the polymerization was terminated to prepare a styrene / butadiene rubber polymer latex (gel content: 1 wt%, average particle size: 40 nm, refractive index: 1.5350).

[0088] <Preparation of Grafted Polymers>

[0089] A liquid mixture comprising 200 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 25.7 parts by weight of methyl methacrylate, 21.8 parts by weight of styrene, 2.5 parts by weight of acrylonitrile, 0.4 parts by weight of tert-dodecyl mercaptan, 0.050 parts by weight of ethylenediaminetetraacetic acid, 0.100 parts by weight of sodium formaldehyde sulfoxylate, 0.001 parts by weight of ferrous sulfate and 0.2 parts by weight of cumene hydroperoxide was prepared.

[0090] Fifty parts by weight (based on solids content) of styrene / butadiene rubber polymer latex were added to a reactor. Polymerization was then carried out simultaneously with the continuous addition of the liquid mixture to the reactor at 60°C for 5 hours. After the continuous addition of the liquid mixture was completed, aging was performed at 60°C for 1 hour, and polymerization was terminated to prepare the grafted polymer latex. The entire amount of the grafted polymer latex was added to an aqueous solution containing 2 parts by weight of calcium chloride, and the mixture was coagulated, aged, washed, dehydrated, and dried to prepare a grafted polymer powder (refractive index: 1.5350).

[0091] Preparation Example 3

[0092] <Preparation of Rubber Polymers>

[0093] 200 parts by weight of deionized water, 25 parts by weight of styrene, 75 parts by weight of 1,3-butadiene, 3.0 parts by weight of potassium oleate, 3.0 parts by weight of potassium rosinate, 0.1 parts by weight of cumene hydroperoxide, 1.0 part by weight of tert-dodecyl mercaptan, 0.010 parts by weight of sodium pyrophosphate, 0.050 parts by weight of glucose, and 0.001 parts by weight of ferrous sulfate were added in batches to a nitrogen-purified polymerization reactor (autoclave) and polymerized at 15°C. When the polymerization conversion reached 60%, the polymerization was terminated to prepare a styrene / butadiene rubber polymer latex (gel content: 5 wt%, average particle size: 40 nm, refractive index: 1.5350).

[0094] <Preparation of Grafted Polymers>

[0095] Except for using the styrene / butadiene rubber polymer latex described above, the grafted polymer powder (refractive index: 1.5350) was prepared in the same manner as in Preparation Example 2.

[0096] Preparation Example 4

[0097] <Preparation of Rubber Polymers>

[0098] 200 parts by weight of deionized water, 25 parts by weight of styrene, 75 parts by weight of 1,3-butadiene, 2.0 parts by weight of potassium oleate, 3.0 parts by weight of potassium rosinate, 0.1 parts by weight of potassium persulfate, 0.8 parts by weight of tert-dodecyl mercaptan, 0.010 parts by weight of sodium pyrophosphate, 0.050 parts by weight of glucose, and 0.001 parts by weight of ferrous sulfate were added in batches to a nitrogen-purified polymerization reactor (autoclave) and polymerized at 10°C. When the polymerization conversion reached 65%, the polymerization was terminated to prepare a styrene / butadiene rubber polymer latex (gel content: 15 wt%, average particle size: 40 nm, refractive index: 1.5350).

[0099] <Preparation of Grafted Polymers>

[0100] Except for using the styrene / butadiene rubber polymer latex described above, the grafted polymer powder (refractive index: 1.5350) was prepared in the same manner as in Preparation Example 2.

[0101] Preparation Example 5

[0102] <Preparation of Rubber Polymers>

[0103] 200 parts by weight of deionized water, 25 parts by weight of styrene, 75 parts by weight of 1,3-butadiene, 1.0 part by weight of potassium oleate, 1.0 part by weight of potassium rosinate, 0.2 parts by weight of potassium persulfate, 0.3 parts by weight of tert-dodecyl mercaptan, 0.010 parts by weight of sodium pyrophosphate, 0.050 parts by weight of glucose, and 0.001 parts by weight of ferrous sulfate were added in batches to a nitrogen-purified polymerization reactor (autoclave) and polymerized at 70°C. When the polymerization conversion reached 93%, the polymerization was terminated to prepare a styrene / butadiene rubber polymer latex (gel content: 65 wt%, average particle size: 300 nm, refractive index: 1.5350).

[0104] <Preparation of Grafted Polymers>

[0105] Except for using the styrene / butadiene rubber polymer latex described above, the grafted polymer powder (refractive index: 1.5350) was prepared in the same manner as in Preparation Example 2.

[0106] Preparation Example 6

[0107] <Preparation of Rubber Polymers>

[0108] 200 parts by weight of deionized water, 25 parts by weight of styrene, 75 parts by weight of 1,3-butadiene, 2.0 parts by weight of potassium oleate, 1.0 parts by weight of potassium rosinate, 0.3 parts by weight of potassium persulfate, 0.3 parts by weight of tert-dodecyl mercaptan, 0.010 parts by weight of sodium pyrophosphate, 0.050 parts by weight of glucose, and 0.001 parts by weight of ferrous sulfate were added in batches to a nitrogen-purified polymerization reactor (autoclave) and polymerized at 70°C. When the polymerization conversion reached 99%, the polymerization was terminated to prepare a styrene / butadiene rubber polymer latex (gel content: 90 wt%, average particle size: 90 nm, refractive index: 1.5350).

[0109] <Preparation of Grafted Polymers>

[0110] Except for using the styrene / butadiene rubber polymer latex described above, the grafted polymer powder (refractive index: 1.5350) was prepared in the same manner as in Preparation Example 2.

[0111] Preparation Example 7

[0112] Use methyl methacrylate homopolymer (commercially available from LG MMACorp., IH830, refractive index: 1.4900).

[0113] Preparation Example 8

[0114] A liquid mixture comprising 86 parts by weight of methyl methacrylate, 14 parts by weight of styrene, 3 parts by weight of toluene, 0.01 parts by weight of 1,1-bis(tert-butylperoxy)cyclohexane and 0.4 parts by weight of tert-dodecyl mercaptan was prepared.

[0115] Polymerization was carried out in a reactor with an average polymerization time of 3 hours while the liquid mixture was continuously added to the reactor. The reactor temperature was 148°C. The polymerization solution discharged from the reactor was heated in a preheating bath, and unreacted monomers were volatilized in an evaporation tank to prepare the polymer. Then, while maintaining a temperature of 210°C, the polymer was transferred to a polymer transfer pump extruder to prepare ungrafted polymer pellets (refractive index: 1.5040).

[0116] Examples 1 to 4 and Comparative Examples 1 to 4

[0117] The grafted polymer and non-grafted polymer of the preparation example were mixed in the amounts described in Tables 1 and 2 below to prepare a thermoplastic resin composition.

[0118] Experimental Example 1

[0119] The physical properties of the rubber polymers prepared in the example were evaluated by the following methods, and the results are shown in Tables 1 and 2 below.

[0120] 1) Gel content (wt%): The rubber polymer latex was coagulated with calcium chloride, washed, and dried in a vacuum oven at 60°C for 24 hours to obtain a rubber block. The rubber block was cut with scissors to prepare a 1g rubber fragment. The rubber fragment was added to 100g of toluene and stored in a dark room at 23°C for 48 hours to separate the sol and gel. The weights of the sol and gel were substituted into the following equation to calculate the gel content.

[0121] Gel content (wt%) = weight of gel / weight of rubber segment × 100

[0122] 2) Average particle size (nm): Measured using a Nicomp 380 instrument (commercially available from Particle Sizing Systems) via dynamic light scattering.

[0123] 3) Refractive index: The rubber fragment prepared in the gel content measurement was unfolded to a thickness of 0.2 mm and measured at 25 °C using visible light with a wavelength of 589.3 nm using an Abbe refractometer.

[0124] Experimental Example 2

[0125] The composition of the thermoplastic resin compositions of the examples and comparative examples was measured by the following methods, and the results are shown in Tables 1 and 2 below.

[0126] 1) Content (wt%) of styrene / butadiene rubber polymer, methyl methacrylate monomer units, styrene monomer units, and acrylonitrile monomer units: using Nicolet TM The iS20 FTIR spectrometer (commercially available from ThermoScientific) calculates the content of rubber polymer and monomer units in thermoplastic resin compositions using infrared (IR) spectroscopy.

[0127] Experimental Example 3

[0128] 100 parts by weight of each thermoplastic resin composition of the Examples and Comparative Examples were mixed with 0.2 parts by weight of an antioxidant and extruded to prepare granules. The granules were injection molded to prepare test specimens, and the physical properties of the specimens were evaluated by the following methods. The results are shown in Tables 1 and 2 below.

[0129] 1) Gloss (45°): The gloss of the sample (thickness: 3 mm) was measured at 45° using a gloss meter (commercially available from Nippon Denshoku Industries Co., Ltd., VG7000). It was determined that a matte finish was achieved when the gloss value was below 30, and the lower the gloss value, the better the matte finish.

[0130] 2) Gloss (60°): The gloss of the sample (thickness: 3 mm) was measured at 60° using a gloss meter (commercially available from Nippon Denshoku Industries Co., Ltd., VG7000). It was determined that a matte finish was achieved when the gloss value was below 30, and the lower the gloss value, the better the matte finish.

[0131] 3) Impact strength (kgf·cm / cm): The notched cantilever beam impact strength of the specimen (1 / 4 inch) is measured at 23°C according to ASTM D256.

[0132] 4) Pencil hardness: Measured according to ASTM D3365.

[0133] [Table 1]

[0134]

[0135]

[0136] [Table 2]

[0137]

[0138]

[0139] Referring to Tables 1 and 2, Examples 1 to 4, comprising grafted polymers containing rubber polymers with a gel content of 0% to 5% by weight and an average particle size of 40 nm, achieved excellent impact resistance and abrasion resistance while also achieving a matte finish. However, Comparative Example 1, comprising a grafted polymer containing rubber polymers with a gel content of 15% by weight and an average particle size of 40 nm, did not achieve a matte finish. Furthermore, Comparative Example 2, comprising a grafted polymer containing rubber polymers with a gel content of 65% by weight and an average particle size of 300 nm, did not achieve a matte finish and exhibited deteriorated abrasion resistance. Moreover, although the rubber polymer of Comparative Example 2 had a much larger average particle size, it exhibited an impact resistance level comparable to that of Examples 1 to 4.

[0140] Furthermore, Comparative Example 3, which contained a grafted polymer comprising a rubber polymer with a gel content of 90% by weight and an average particle size of 90 nm, did not achieve matte properties. Additionally, although the rubber polymer of Comparative Example 3 had a much larger average particle size, its impact resistance was deteriorated compared to Examples 1 to 4.

[0141] In addition, Comparative Example 4, which contains a non-grafted polymer with less than 90% by weight of methyl methacrylate monomer units, exhibits a pencil hardness of HB, and therefore, its scratch resistance is deteriorated compared to Examples 1 to 4.

Claims

1. A thermoplastic resin composition comprising: A grafted polymer comprising a rubber polymer having a gel content of 0% to 10% by weight and containing aromatic vinyl monomer units and diene monomer units, and a shell comprising (meth)acrylate monomer units and aromatic vinyl monomer units grafted onto the rubber polymer; and The ungrafted polymer contains more than 90% by weight of (meth)acrylate monomer units. in, The method for calculating the gel content includes: The rubber polymer latex is coagulated with a dilute acid or a metal salt, then washed and dried in a vacuum oven at 60°C for 24 hours to obtain a rubber block, wherein the dilute acid includes one or more selected from hydrochloric acid, sulfuric acid or formic acid, and the metal salt includes one or more selected from magnesium sulfate, calcium chloride, aluminum sulfate; The rubber block was cut with scissors to prepare a 1g rubber fragment; The rubber fragment was placed in 100g of toluene and stored in a dark room at 23°C for 48 hours to separate the sol and gel; and The gel content is calculated by substituting the weights of the sol and gel into the following equation; Equation 1 Gel content (weight %) = weight of gel / weight of rubber segment × 100.

2. The thermoplastic resin composition according to claim 1, wherein, The gel content of the rubber polymer is from 0% to 5% by weight.

3. The thermoplastic resin composition according to claim 1, wherein, The rubber polymer contains aromatic vinyl monomer units and diene monomer units in a weight ratio of 10:90 to 35:

65.

4. The thermoplastic resin composition according to claim 1, wherein, The average particle size of the rubber polymer is 20 nm to 100 nm.

5. The thermoplastic resin composition according to claim 1, wherein, The graft polymer comprises: 30.0% to 65.0% by weight of the rubber polymer; 10.0% to 55.0% by weight of the (meth)acrylate monomer units; and 5.0% to 40.0 wt% of the aromatic vinyl monomer units.

6. The thermoplastic resin composition according to claim 1, wherein, The ungrafted polymer comprises one or more monomer units selected from (meth)acrylic acid monomer units and aromatic vinyl monomer units.

7. The thermoplastic resin composition according to claim 1, wherein, The thermoplastic resin composition comprises: 10.0% to 50.0% by weight of the grafted polymer; and 50.0% to 90.0% by weight of the ungrafted polymer.

8. The thermoplastic resin composition according to claim 1, wherein, The shell of the grafted polymer contains vinyl cyanide monomer units grafted onto the rubber polymer.

9. The thermoplastic resin composition according to claim 1, wherein, The thermoplastic resin composition comprises: 5.0% to 25.0% by weight of the rubber polymer; 60.0% to 90.0% by weight of the (meth)acrylate monomer units; and 3.0% to 20.0% by weight of the aromatic vinyl monomer units.

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