阅读说明：本技术 共聚物的制备方法和共聚物 (Method for producing copolymer and copolymer ) 是由 许宰源 金英玟 于 2018-10-01 设计创作，主要内容包括：本发明涉及一种共聚物的制备方法、根据该制备方法制备的共聚物,和使用所述共聚物制造的热塑性树脂模制品,所述制备方法包括：添加表面改性的二氧化硅纳米粉、乙烯基氰基类单体和芳香族乙烯基类单体并且使它们聚合,其中,所述表面改性的二氧化硅纳米粉是被用于可逆加成-断裂链转移聚合的链转移剂表面改性的二氧化硅纳米粉。更具体地,本发明涉及一种具有改善的热收缩性和反射雾度的共聚物的制备方法；共聚物；和热塑性树脂模制品。(The present invention relates to a method for preparing a copolymer, a copolymer prepared according to the method, and a thermoplastic resin molded article manufactured using the copolymer, the method comprising: adding and polymerizing surface-modified silica nanopowder, vinyl cyano-based monomer and aromatic vinyl-based monomer, wherein the surface-modified silica nanopowder is surface-modified silica nanopowder that is surface-modified by a chain transfer agent for reversible addition-fragmentation chain transfer polymerization. More particularly, the present invention relates to a method for preparing a copolymer having improved heat shrinkability and reflection haze; a copolymer; and a thermoplastic resin molded article.)

1. A method of making a copolymer comprising:

adding surface-modified silica nanopowder, vinyl cyano-based monomer and aromatic vinyl-based monomer and polymerizing them,

wherein the surface-modified silica nanopowder is a silica nanopowder surface-modified by a chain transfer agent for reversible addition-fragmentation chain transfer polymerization.

2. The production method according to claim 1, wherein the chain transfer agent for reversible addition-fragmentation chain transfer polymerization is one or more sulfur compounds selected from the group consisting of 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid, 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid, and 2- (dodecylsulfanylthiocarbonylthio) -2-methylpropanoic acid.

3. The preparation method of claim 1, wherein the silica nanopowder further comprises hydroxyl groups.

4. The preparation method of claim 1, wherein the silica nanopowder has an average particle size of 1 to 100 nm.

5. The preparation method of claim 1, wherein the silica nanopowder has an average particle size of 5 to 50 nm.

6. The preparation method of claim 1, wherein the surface-modified silica nano powder is added in an amount of 0.01 to 2 parts by weight, based on 100 parts by weight of the sum of the vinyl cyano-based monomer and the aromatic vinyl-based monomer.

7. The preparation method of claim 1, wherein the surface-modified silica nano powder is added in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the sum of the vinyl cyano-based monomer and the aromatic vinyl-based monomer.

8. The production method according to claim 1, wherein the polymerization is suspension polymerization.

9. A copolymer, comprising:

silicon dioxide nano powder;

units derived from sulfur compounds;

units derived from a vinyl cyano-based monomer; and

units derived from an aromatic vinyl monomer.

10. The copolymer of claim 9, wherein the units derived from a sulfur compound are derived from one or more sulfur compounds selected from the group consisting of 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid, 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid, and 2- (dodecylsulfanylthiocarbonylthio) -2-methylpropionic acid.

11. A thermoplastic resin molded article manufactured using a thermoplastic resin composition comprising: the copolymer according to claim 9 or 10; a matrix copolymer comprising units derived from an aromatic vinyl monomer and units derived from a vinyl cyano monomer; and a graft copolymer comprising a conjugated diene polymer, a unit derived from an aromatic vinyl monomer, and a unit derived from a vinyl cyano monomer,

wherein the thermoplastic resin molded article has a reflection haze of 2 or less.

Technical Field

[ Cross-reference to related applications ]

The present application claims priority rights of korean patent application No.10-2017-0127975 filed in the korean intellectual property office at 29.09.2017 and korean patent application No.10-2018-0116461 filed in the korean intellectual property office at 28.09.2018, the disclosures of both applications being incorporated herein by reference.

Background

SAN copolymers prepared by polymerizing styrene and acrylonitrile have excellent processability and heat resistance, and thus, demand for them is increasing. SAN copolymers are used mainly in household appliances, automobiles, packaging, construction, medical devices, and the like. Further, the SAN copolymer was used as a matrix copolymer of the ABS graft copolymer to prepare a thermoplastic resin composition. The SAN copolymer has excellent flowability and is used to shorten a molding cycle at the time of molding, thereby providing high productivity and economic benefits.

SAN copolymers can be made into articles by mixing with ABS graft copolymers and injection molding at elevated temperature and pressure, followed by cooling at room temperature and atmospheric pressure. However, during the production of an article using the SAN copolymer, the total volume may excessively shrink, and thus, the appearance of the article may be deformed and warped (distorted), and thus, the dimensional stability may be reduced. Therefore, studies to improve the heat shrinkage problem of the styrene-acrylonitrile copolymer to improve the dimensional stability of the final product have been continuously conducted.

Disclosure of Invention

Technical problem

The present invention aims to provide a method for preparing a copolymer having improved heat shrinkability and reflection haze.

Technical scheme

According to an aspect of the present invention, there is provided a method for preparing a copolymer, comprising suspension polymerizing surface-modified silica nanopowder, a vinyl cyano-based monomer and an aromatic vinyl-based monomer, wherein the surface-modified silica nanopowder is a silica nanopowder surface-modified by a chain transfer agent for reversible addition-fragmentation chain transfer polymerization.

According to another aspect of the present invention, there is provided a copolymer comprising: silicon dioxide nano powder; units derived from sulfur compounds; units derived from a vinyl cyano-based monomer; and units derived from an aromatic vinyl monomer.

Advantageous effects

By using the preparation method of the copolymer according to the present invention, a vinyl cyano-based monomer and an aromatic vinyl-based monomer can be easily graft-polymerized to the surface of the surface-modified silica nano-powder, whereby the surface-modified silica nano-powder can be more uniformly distributed in the copolymer, and the bonding force between the surface-modified silica nano-powder and the unit derived from the aromatic vinyl monomer and between the surface-modified silica nano-powder and the unit derived from the vinyl cyano-based monomer can be significantly improved.

In addition, due to such structural features, an increase in reflection haze of the copolymer, i.e., deterioration of appearance characteristics, due to the silica nanopowder can be prevented.

In addition, the surface-modified silica nano powder may improve the graft polymerization efficiency, and thus, the dispersibility of the silica nano powder may be significantly improved, and the dimensional stability of the thermoplastic resin molded product may be significantly improved.

Drawings

Fig. 1 shows the results of thermogravimetric analysis (TGA) of the silica nano powder of preparative example 1 and the silica nano powder of comparative preparative example 1.

Detailed Description

Hereinafter, the present invention will be described to help understanding of the present invention.

The terms or words used in the present specification and the appended claims should not be limited to conventional or dictionary meanings, but have meanings and concepts corresponding to technical aspects of the embodiments of the present invention in order to best express the embodiments of the present invention.

In the present invention, the average particle size of the silica nanopowder may be measured using NICOMP370 HPL (product name) (manufacturer: NICOMP) after dispersing the silicon nanopowder in methanol to a concentration of 0.1 wt% and sonicating with a sonicator (manufacturer: Malik Scientific glass works) for one hour.

In the present invention, the weight average molecular weight of the copolymer can be measured as a relative value to a standard Polystyrene (PS) sample using Tetrahydrofuran (THF) as an eluent, using Gel Permeation Chromatography (GPC).

In the present invention, the coefficient of thermal expansion (ppm/K) of the film can be measured using a thermo-mechanical analysis (TMA) apparatus (manufacturer: TAInstructions, product name: Q400 TMA). The change in the film length can be measured at room temperature (25 ℃) to 90 ℃, and the CTE value can be calculated according to the following equation. The value of the second cycle is preferably used to increase the reliability of the data.

△ L ═ film length after increase at 90 deg.C (film length at room temperature)

Lo-film length at room temperature

△ T-varying temperature

In the present invention, reflection haze can be measured using a Rhopoint IQ device (product name) manufacturer: Rhopoint instruments, using 512 diodes arranged in a line to draw 14 to 27 degrees of reflected light on a large circular arc. Here, a small reflection haze indicates excellent appearance characteristics.

1. Method for preparing copolymer

The method of preparing a copolymer according to one embodiment of the present invention includes adding surface-modified silica nanopowder, a vinyl cyano-based monomer and an aromatic vinyl-based monomer and polymerizing them. The surface-modified silica nanopowder is a silica nanopowder surface-modified by a chain transfer agent for reversible addition-fragmentation chain transfer (RAFT) polymerization.

The chain transfer agent for RAFT polymerisation may be a sulphur compound. The sulfur compound may be one or more selected from the group consisting of 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid, 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid, and 2- (dodecylsulfanylthiocarbonylthio) -2-methylpropionic acid. Among them, 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid is preferable.

Due to the functional group of the surface-modified silica nanopowder derived from the sulfur compound, the vinyl cyano monomer and the aromatic vinyl monomer can be easily graft-polymerized to the surface of the surface-modified silica nanopowder, and therefore, the surface-modified silica nanopowder can be uniformly distributed in the copolymer, and the bonding force between the surface-modified silica nanopowder and the units derived from the aromatic vinyl monomer and between the surface-modified silica nanopowder and the units derived from the vinyl cyano monomer can be significantly improved.

Due to such structural characteristics, the surface-modified silica nanopowder can be uniformly distributed in the copolymer. Therefore, an increase in reflection haze, i.e., deterioration of appearance characteristics, due to the silica nanopowder can be prevented.

Meanwhile, the surface-modified silica nano powder shows remarkably superior thermal stability compared to the silica nano powder which is not surface-modified. Therefore, the copolymer including the surface-modified silica nano-powder also exhibits significantly improved heat shrinkage, and a thermoplastic resin molded article manufactured using the copolymer may exhibit improved dimensional stability.

Meanwhile, the silica nanopowder may further comprise hydroxyl groups. More specifically, the silica nanopowder may be a hydrophilic fumed silica nanopowder comprising hydroxyl groups present on the surface thereof.

The surface-modified silica nanopowder can be prepared by reacting a silica nanopowder with a sulfur compound, more specifically, by esterifying hydroxyl groups present on the surface of a hydrophilic fumed silica nanopowder with a sulfur compound.

Thus, the surface-modified silica nanopowder may contain unreacted hydroxyl groups present on the surface thereof.

The surface-modified silica nanopowder may be reacted with a sulfur compound in a molar ratio of 1:500 to 1:2,000, 1:700 to 1:1,500, or 1:800 to 1:1,000. Among them, the preferred molar ratio is 1:800 to 1:1,000.

Within these ranges, the efficiency of esterification can be maximized while minimizing the residual amount of sulfur compounds.

Meanwhile, the hydrophilic fumed silica can be prepared according to the following reaction scheme 1:

[ reaction scheme 1]

Si+4HCl→SiCl₄+2H₂

2H₂+O₂+SiCl₄+SiC₂+4HCl

Referring to reaction scheme 1, first, silicon is reacted with hydrogen chloride to produce chlorosilane. The chlorosilane is hydrolyzed in a flame of 1,000 ℃ or higher formed of oxygen and hydrogen, thereby generating hydrophilic fumed silica containing hydroxyl groups present on the surface thereof, i.e., silica containing hydroxyl groups present on the surface thereof.

The base particles (primary particles) of the hydrophilic fumed silica produced by the flame in this manner collide with each other in a state where the surface of the hydrophilic fumed silica is dissolved, thereby being formed into secondary particles. Hydrogen chloride gas remaining in the silica is removed under high temperature air conditions, and the average particle diameter and specific surface area of the silica can be adjusted by changing the composition of the reactants and the temperature of the flame. The hydrophilic fumed silica can be amorphous silica.

The hydrophilic fumed silica can be prepared by the above-described method, or commercially available hydrophilic fumed silica can be used.

In addition, the average particle diameter of the silica nanopowder may be 100nm or less, 1nm to 100nm, or 5nm to 50 nm. Among them, the average particle diameter is preferably 5nm to 50 nm.

Within these ranges, the silica nanopowder can be uniformly dispersed in the reaction solution, and thus, can be more uniformly distributed in the copolymer. Therefore, an increase in reflection haze, i.e., deterioration of appearance characteristics, due to the silica nanopowder can be prevented.

The surface-modified silica nano powder may be added in an amount of 0.01 to 2.0 parts by weight, 0.01 to 1.5 parts by weight, or 0.1 to 1.0 parts by weight, based on 100 parts by weight of the total of the vinyl cyanide-based monomer and the aromatic vinyl-based monomer. Among them, an amount of 0.1 to 1.0 part by weight is preferable.

Within these ranges, the vinyl cyanide-based monomer and the aromatic vinyl-based monomer may be easily graft-polymerized to the surface of the surface-modified silica nano powder, whereby the surface-modified silica nano powder may be more uniformly distributed in the copolymer, and the bonding force between the surface-modified silica nano powder and the unit derived from the aromatic vinyl monomer and between the surface-modified silica nano powder and the unit derived from the vinyl cyano-based monomer may be significantly improved. Further, due to the silica nanopowder, excellent impact resistance and surface gloss can be achieved while suppressing an increase in reflection haze, i.e., deterioration of appearance characteristics, and also the heat shrinkability of the copolymer can be significantly improved.

Meanwhile, the thermal expansion coefficient is, as a numerical value, an expansion rate per unit temperature due to heat at a predetermined pressure, and the expansion rate and the contraction rate are inherent properties of an object. In addition, due to the temperature-dependent density difference of the copolymer, thermal shrinkage and expansion of the copolymer occur. For example, although the coefficient of thermal expansion of a copolymer comprising units derived from styrene and units derived from acrylonitrile is 50X 10^-6To 150X 10^-6K^-1(based on the thickness: 1 μm to 2 μm), since the surface-modified silica nano powder of the present invention has a low thermal expansion coefficient, when the surface-modified silica nano powder of the present invention is included in a copolymer, the thermal expansion coefficient of the copolymer can be improved. Therefore, the method comprises the following steps: a conjugated diene polymer; a graft copolymer comprising units derived from a vinyl cyano monomer and a vinyl cyano monomer; and a matrix copolymer comprising a unit derived from a vinyl cyano monomer and a unit derived from an aromatic vinyl monomer, can reduce problems occurring during molding at room temperature and atmospheric pressure after injection molding at high temperature and high pressure. More specifically, in the case of the thermoplastic resin composition, the energy of chain molecules in the copolymer is reduced during molding, and thus, the distance between the chain molecules is reduced. Therefore, the density of the resin composition may increase, and the total volume of the thermoplastic resin composition may shrink. On the other hand, when the surface-modified silica nanopowder is contained in the matrix copolymer, the distance between chain molecules in the thermoplastic resin can be prevented from being reduced, whereby the deformation and warpage of the appearance of the thermoplastic resin molded article can be reduced, and the dimensional stability thereof can be improved.

The vinyl cyanide-based monomer may be one or more selected from acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, chloroacrylonitrile, and α - (cyanoethyl) -acrylonitrile, among which acrylonitrile is preferred.

The aromatic vinyl monomer may be one or more selected from the group consisting of styrene, α -methylstyrene, p-bromostyrene, p-methylstyrene, p-chlorostyrene and o-bromostyrene, among which styrene is preferred.

The vinyl cyano monomer and the aromatic vinyl monomer may be added in a weight ratio of 15:85 to 35:65 or 20:80 to 30:70, specifically 20:80 to 30: 70.

Within these ranges, a copolymer having excellent processability, heat resistance and chemical resistance can be prepared.

Meanwhile, the polymerization may be suspension polymerization.

The polymerization step may be a step of adding the surface-modified silica nano powder, the vinyl cyano-based monomer, the aromatic vinyl-based monomer, the initiator, and the suspension stabilizer to water and stirring, and then performing polymerization at 70 to 90 ℃.

The initiator may be one or more selected from the group consisting of a water-soluble polymerization initiator, a fat-soluble polymerization initiator, and a redox catalyst. Among them, a fat-soluble polymerization initiator is preferable.

The water-soluble polymerization initiator may be one or more selected from the group consisting of potassium persulfate, sodium persulfate, and ammonium persulfate.

The fat-soluble polymerization initiator may be one or more selected from the group consisting of cumene hydroperoxide, diisopropylbenzene hydroperoxide, azobis (isobutyronitrile), t-butyl hydroperoxide, p-menthane hydroperoxide and benzoyl peroxide. Among them, azobis (isobutyronitrile) is preferable.

The redox catalyst may include one or more selected from the group consisting of sodium formaldehyde, sulfoxylate, sodium ethylenediaminetetraacetate, ferrous sulfate, glucose, sodium sulfite, potassium pyrophosphate, sodium pyrophosphate, potassium phosphate, sodium phosphate, potassium hydrogen phosphate and sodium hydrogen phosphate. Specifically, the redox catalyst may include one or more selected from the group consisting of ferrous sulfate, glucose, and sodium pyrophosphate.

The content of the initiator is not particularly limited, and may be 0.1 to 2.0 parts by weight, 0.1 to 1.5 parts by weight, or 0.1 to 1 part by weight, based on 100 parts by weight of the total of the vinyl cyanide-based monomer and the aromatic vinyl-based monomer.

Within these ranges, the polymerization conversion of the monomer can be simultaneously increased. In addition, radicals for initiating polymerization can be sufficiently generated, and polymerization can be easily performed.

The suspension stabilizer may be one or more selected from the group consisting of water-soluble polyvinyl alcohol, oil-soluble partially saponified polyvinyl alcohol, polyacrylic acid, a copolymer of vinyl acetate and maleic anhydride, hydroxypropylmethylcellulose, gelatin, calcium phosphate, tricalcium phosphate, hydroxyapatite, sorbitan monolaurate, sorbitan trioleate, polyoxyethylene, sodium lauryl sulfate, sodium dodecylbenzenesulfonate and dioctyl sodium sulfosuccinate. Among them, tricalcium phosphate is preferable.

The suspension stabilizer may be added in an amount of 0.01 to 2 parts by weight, 0.05 to 1.5 parts by weight, or 0.1 to 1 part by weight, based on 100 parts by weight of the sum of the vinyl cyanide-based monomer and the aromatic vinyl-based monomer. Among them, an amount of 0.1 to 1 part by weight is preferable.

Within these ranges, high polymerization stability is exhibited, and deterioration in the properties of the copolymer due to the suspension stabilizer can be prevented.

In the polymerization step, a molecular weight regulator may also be added.

The molecular weight modifier may be one or more selected from the group consisting of α -methylstyrene dimer, t-dodecylmercaptan, n-dodecylmercaptan, octylmercaptan, carbon tetrachloride, methylene chloride, methylene bromide, tetraethylthiuram disulfide, dipentamethylenethiuram disulfide, and diisopropylxanthogen disulfide.

The molecular weight modifier may be added in an amount of 0.1 to 1.0 part by weight, 0.1 to 0.8 part by weight, or 0.1 to 0.5 part by weight, based on 100 parts by weight of the total of the vinyl cyanide-based monomer and the aromatic vinyl-based monomer.

Within these ranges, a copolymer having an appropriate weight average molecular weight may be prepared.

The surface-modified silica nano powder having excellent thermal stability may be uniformly distributed in the copolymer prepared according to one embodiment of the present invention, and the bonding force between the surface-modified silica nano powder and the unit derived from the vinyl cyano-based monomer and between the surface-modified silica nano powder and the unit derived from the aromatic vinyl-based monomer is excellent. Due to such structural features, the copolymer may exhibit excellent heat shrinkability and reduced reflection haze.

The graft ratio of the copolymer may be 20% to 90%, 40% to 90%, or 50% to 90%. Among them, the graft ratio is preferably 50% to 90%.

Within these ranges, the surface-modified silica nano powder may be easily subjected to graft polymerization, and thus, the surface-modified silica nano powder may be easily dispersed and its dimensional stability may be effectively improved.

The graft ratio can be calculated using the solubility of the copolymer in an organic solvent such as acetone. More specifically, since the copolymer grafted to the surface of the silica nano powder in the copolymer is insoluble in acetone, the proportion of the grafted copolymer can be calculated from the proportion of the copolymer that is not adsorbed to the surface of the silica nano powder.

2. Copolymer

The copolymer according to another embodiment of the present invention may include silica nanopowders, units derived from a sulfur compound, units derived from a vinyl cyano-based monomer and units derived from an aromatic vinyl-based monomer.

The silica nanopowder and the units derived from a sulfur compound are derived from surface-modified silica nanopowder. The sulfur compound may be derived from one or more sulfur compounds selected from the group consisting of 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid, 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid, and 2- (dodecylsulfanylthiocarbonylthio) -2-methylpropionic acid, which are chain transfer agents for reversible addition-fragmentation chain transfer polymerization.

The weight average molecular weight of the copolymer can be from 100,000g/mol to 150,000g/mol, 105,000g/mol to 140,000g/mol, or 110,000g/mol to 130,000 g/mol. Among them, the weight average molecular weight is preferably 110,000g/mol to 130,000 g/mol.

Within these ranges, the copolymer may exhibit excellent mechanical properties and flowability.

In addition, the copolymer may have a glass transition temperature of 90 ℃ or more, 90 ℃ to 130 ℃, 95 ℃ to 125 ℃, or 100 ℃ to 120 ℃. Among them, the glass transition temperature is preferably 100 ℃ to 120 ℃.

Within these ranges, the copolymer may exhibit excellent heat resistance and improved process efficiency during injection molding.

The other description of the copolymer is the same as in "1. copolymer preparation method", and a copolymer according to another embodiment of the present invention may be prepared according to a graft copolymer preparation method according to one embodiment of the present invention.

3. Thermoplastic resin composition

The thermoplastic resin composition according to still another embodiment of the present invention comprises: a copolymer according to another embodiment of the present invention; a matrix copolymer comprising units derived from an aromatic vinyl monomer and units derived from a vinyl cyano monomer; and a graft copolymer comprising a conjugated diene polymer, a unit derived from an aromatic vinyl monomer, and a unit derived from a vinyl cyano monomer.

The matrix copolymer may include a unit derived from an aromatic vinyl monomer and a unit derived from a vinyl cyano monomer. The unit from the aromatic vinyl-based monomer and the unit from the vinyl cyano-based monomer may be included in a weight ratio of 85:15 to 65:35 or 80:20 to 70: 30. Among them, the weight ratio is preferably 80:20 to 70: 30.

Within these ranges, a thermoplastic resin molded article having excellent processability, chemical resistance and heat resistance can be manufactured.

The graft copolymer comprises a conjugated diene polymer, a unit derived from an aromatic vinyl monomer, and a unit derived from a vinyl cyano monomer.

The conjugated diene polymer is prepared from conjugated diene monomers. The conjugated diene monomer may be one or more selected from 1, 3-butadiene, isoprene, chloroprene and piperylene. Among them, 1, 3-butadiene is preferable.

The average particle diameter of the conjugated diene-based polymer may be 50nm to 500nm, 50nm to 400nm, or 80nm to 400 nm. Among them, the average particle diameter is preferably 80nm to 400 nm.

Within these ranges, the graft copolymer may exhibit excellent impact resistance and surface gloss.

The content of the conjugated diene-based polymer may be 45 to 75% by weight or 50 to 70% by weight, based on the total weight of the conjugated diene-based polymer, the aromatic vinyl-based monomer, and the vinyl cyano-based monomer. Among them, the content is preferably 50 to 70% by weight.

Within these ranges, the graft copolymer may exhibit improved impact resistance and processability.

The aromatic vinyl monomer may be added in an amount of 15 to 45 wt% or 20 to 40 wt% based on the total weight of the conjugated diene polymer, the aromatic vinyl monomer, and the vinyl cyano monomer. Among them, an amount of 20 to 40% by weight is preferable.

Within these ranges, the graft copolymer may exhibit further improved chemical resistance, rigidity, impact resistance, processability, and surface gloss.

The vinyl cyanide-based monomer may be added in an amount of 1 to 20% by weight or 5 to 15% by weight, based on the total weight of the conjugated diene-based polymer, the aromatic vinyl-based monomer, and the vinyl cyano-based monomer. Among them, an amount of 5 to 15% by weight is preferable.

Within these ranges, the graft copolymer may exhibit further improved chemical resistance, rigidity, impact resistance, processability, and surface gloss.

The thermoplastic resin composition may include, based on the total weight of the thermoplastic resin composition: 10 to 30 weight percent of the copolymer; 45 to 65 wt% of the matrix copolymer; and 15 to 35 weight percent of the graft copolymer. Preferably, it comprises: 15 to 25 weight percent of the copolymer; 50 to 60 weight percent of the matrix copolymer; and 20 to 30 weight percent of the graft copolymer.

Within these ranges, the thermoplastic resin composition may exhibit excellent appearance characteristics, heat resistance, and processability.

4. Thermoplastic resin molded article

A thermoplastic resin molded article manufactured using the thermoplastic resin composition according to still another embodiment of the present invention has a reflection haze of 2 or less, preferably, a reflection haze of 1.95 or less.

Within these ranges, the thermoplastic resin molded article may exhibit further improved appearance characteristics.

Now, exemplary embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present invention may be embodied in various different forms and is not limited to these embodiments.

< preparation of silica nanopowder >

Preparation of example 1

4.32g (0.003mmol) of hydrophilic fumed silica (manufacturer: Aeroil, average particle diameter: 12nm) and 0.75g (2.7mmol) of 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid were dissolved in 95ml of toluene, and 1.3g (6.3mmol) of N, N' -dicyclohexylcarbodiimide and 0.31g (2.5mmol) of 4-dimethylaminopyridine were added thereto, followed by reflux at 25 ℃ for 12 hours. After the reaction was terminated, the reaction was filtered after slowly cooling at room temperature, thereby obtaining surface-modified silica nanopowder containing reactive groups derived from sulfur compounds.

Preparation of example 2

Surface-modified silica nanopowders were obtained in the same manner as in preparation example 1, except that hydrophilic fumed silica (manufacturer: Aeroil, average particle diameter: 50nm) was used instead of hydrophilic fumed silica (manufacturer: Aeroil, average particle diameter: 12 nm).

Comparative preparation example 1

Example 1 was prepared using non-surface-modified hydrophilic fumed silica (manufacturer: Aeroil, average particle diameter: 12nm) as a comparison.

< preparation of copolymer >