THERMOPLASTIC RESIN COMPOSITION INCLUDING (METH)ACRYLATE GRAFT COPOLYMER AND METHOD OF PREPARING THERMOPLASTIC RESIN COMPOSITION
[Technical Field]
[1] [Cross-Reference to Related Application] [2] This application claims priority to Korean Patent Application No. 10-2019-0107752, filed on August 30, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
[3] The present invention relates to a thermoplastic resin composition including a (meth)acrylate graft copolymer and a method of preparing the thermoplastic resin composition. More specifically, the thermoplastic resin composition of the present invention has excellent impact strength and weather resistance and, in particular, has an advantage in expressing a deep black color due to excellent colorability.
[Background Art]
[4] Acrylonitrile-butadiene-styrene resins (hereinafter referred to as "ABS resins") based on conjugated diene rubber have excellent processability, mechanical properties,

and appearance properties, and thus are used in various fields, such as parts of electrical and electronic products, automobiles, small toys, furniture, and building materials. However, since ABS resins are based on butadiene rubber 5 containing chemically unstable unsaturated bonds, a rubber polymer is easily aged by ultraviolet light, which deteriorates weather resistance of the ABS resins. To overcome this problem, painted ABS resins are sometimes used. However, painting causes environmental pollution. In
10 addition, painted products are difficult to recycle, and durability thereof deteriorates.
[5] To overcome the above-described limitations of ABS
resins, alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymers (hereinafter referred to as "ASA
15 resins") without ethylenically unsaturated bonds are used. Although ASA resins have weather resistance, impact resistance, and colorability superior to ABS resins, painted ASA resin products have poor appearance properties such as colorability compared to painted ABS resin products. In
20 addition, as the level of weather resistance required by the market gradually increases, these resins are limited in meeting this requirement.
[6] Therefore, a resin that has colorability superior
to conventional ABS resins or ASA resins and has excellent
25 weather resistance and impact strength needs to be developed.
2

[7] [Related Art Documents]
[8] [Patent Documents]
[9] KR 10-0815995 B1
5 【Disclosure】
【Technical Problem】
[10] Therefore, the present invention has been made in view of the above problems, and it is one object of the present invention to provide a thermoplastic resin
10 composition including a (meth)acrylate graft copolymer and a method of preparing the thermoplastic resin composition. The thermoplastic resin composition of the present invention has excellent impact strength and weather resistance and, in particular, has an advantage in expressing a deep black
15 color due to excellent colorability.
[11] It is another object of the present invention to provide a molded article manufactured using the thermoplastic resin composition of the present invention. [12] The above and other objects can be accomplished by
20 the present disclosure described below.
【Technical Solution】
[13] In accordance with one aspect of the present
invention, provided is a thermoplastic resin composition
25 including a (meth)acrylate graft copolymer and a method of
3

preparing the thermoplastic resin composition, wherein the thermoplastic resin composition includes a graft copolymer (A) containing an alkyl (meth)acrylate rubber core and an alkyl methacrylate compound (co)polymer shell surrounding 5 the alkyl (meth)acrylate rubber core; and a matrix resin (B), wherein the rubber core has an average particle diameter of 40 to 100 nm, the graft copolymer (A) has a grafting degree of 20 to 100 %, and the thermoplastic resin composition has a refractive index of greater than 1.46 and less than 1.49 10 and a blackness (L value) of less than 25.0.
【Advantageous effects】
[14] According to the present invention, a thermoplastic
resin composition including a (meth)acrylate graft copolymer,
15 characterized in that the thermoplastic resin composition has excellent impact strength and weather resistance and, in particular, has an advantage in expressing a deep black color due to excellent colorability, a method of preparing the thermoplastic resin composition, and a molded article
20 manufactured using the thermoplastic resin composition can be provided.
【Best mode】
[15] Hereinafter, a thermoplastic resin composition 25 including a (meth)acrylate graft copolymer, a method of
4

preparing the thermoplastic resin composition, and a molded article manufactured using the thermoplastic resin composition according to the present invention will be described in detail. 5 [16] The present inventors confirmed that, in the preparation of a thermoplastic resin composition including a (meth)acrylate graft copolymer and a matrix resin, when the rubber size and grafting degree of the graft copolymer were controlled to be within predetermined ranges, respectively,
10 and the total refractive index of the thermoplastic resin composition was controlled to be within a predetermined range, weather resistance and colorability were significantly improved while maintaining impact strength. Based on these results, the present inventors conducted
15 further studies to complete the present invention.
[17] The thermoplastic resin composition of the present invention is a thermoplastic resin composition including a graft copolymer (A) containing an alkyl (meth)acrylate rubber core and an alkyl methacrylate compound (co)polymer
20 shell surrounding the alkyl (meth)acrylate rubber core; and a matrix resin (B). In this case, the rubber core has an average particle diameter of 40 to 100 nm, the graft copolymer (A) has a grafting degree of 20 to 100 %, and the thermoplastic resin composition has a refractive index of
25 greater than 1.46 and less than 1.49. Within this range,
5

the thermoplastic resin composition may have excellent impact strength and weather resistance and, in particular, may have an advantage in expressing a deep black color due to excellent colorability. 5 [18] In addition, the present invention may include a thermoplastic resin composition including a graft copolymer (A) containing an alkyl (meth)acrylate rubber core and an alkyl methacrylate compound (co)polymer shell surrounding the alkyl (meth)acrylate rubber core; and a matrix resin (B),
10 wherein the rubber core has an average particle diameter of 40 to 100 nm, the graft copolymer (A) has a grafting degree of 20 to 100 %, and the thermoplastic resin composition has a refractive index of greater than 1.46 and less than 1.49 and a blackness (L value) of less than 25.0. Within this
15 range, the thermoplastic resin composition may have excellent impact strength and weather resistance and, in particular, may have an advantage in expressing a deep black color due to excellent colorability. [19] In addition, the present invention may include a
20 thermoplastic resin composition including a graft copolymer (A) containing an alkyl (meth)acrylate rubber core and an alkyl methacrylate compound (co)polymer shell surrounding the alkyl (meth)acrylate rubber core; and a matrix resin (B), wherein the rubber core has an average particle diameter of
25 40 to 100 nm, the graft copolymer (A) has a grafting degree
6

of 20 to 100 %, the thermoplastic resin composition has a refractive index of greater than 1.46 and less than 1.49, and difference in refractive index between the rubber core, the (co)polymer shell, and the matrix resin is less than 5 0.04. Within this range, the thermoplastic resin composition may have excellent impact strength and weather resistance and, in particular, may have an advantage in expressing a deep black color due to excellent colorability. [20] Hereinafter, each component of the thermoplastic
10 resin composition of the present invention will be described. [21] A) Graft copolymer
[22] A graft copolymer according to the present invention contains an alkyl (meth)acrylate rubber core and an alkyl methacrylate compound (co)polymer shell surrounding
15 the alkyl (meth)acrylate rubber core. In this case, weather resistance and colorability may be excellent.
[23] For example, the rubber core may have an average particle diameter of 40 to 120 nm, preferably 50 to 110 nm, more preferably 60 to 110 nm, still more preferably 60 to
20 100 nm, still more preferably 70 to 100 nm, most preferably 80 to 100 nm. Within this range, weather resistance may be significantly improved, and colorability may be excellent. [24] For example, the rubber core may include an alkyl acrylate and an alkyl methacrylate. In this case, weather
25 resistance may be further improved.
7

[25] For example, the alkyl methacrylate may be included in an amount of 0 to 30 % by weight, preferably 1 to 20 % by weight, more preferably 3 to 10 % by weight, in the rubber core. Within this range, weather resistance may be improved 5 without deterioration in impact resistance.
[26] For example, the rubber core may further include one or more selected from the group consisting of aromatic vinyl compounds and vinyl cyanide compounds. In this case, appearance properties may be excellent.
10 [27] For example, based on 100 % by weight in total of monomers used to prepare a core, the rubber core may include 0 to 30 % by weight, 0 to 20 % by weight, 0.1 to 30 % by weight, or 0.1 to 20 % by weight of one or more selected from the group consisting of aromatic vinyl compounds and
15 vinyl cyanide compounds. Within this range, appearance properties may be excellent.
[28] As a specific example, based on 100 % by weight in total of monomers used to prepare a core, the rubber core may include 0 to 20 % by weight of the aromatic vinyl
20 compound and 0 to 10 % by weight of the vinyl cyanide compound, preferably 0.1 to 20 % by weight of the aromatic vinyl compound and 0.1 to 10 % by weight of the vinyl cyanide compound, more preferably 0.1 to 10 % by weight of the aromatic vinyl compound and 0.1 to 5 % by weight of the
25 vinyl cyanide compound. Within this range, appearance
8

properties may be excellent.
[29] Difference in refractive index between the rubber core and the (co)polymer shell or between the rubber core and the matrix resin is preferably 0.03 or less, as a 5 preferable example, 0.015 to 0.03, more preferably less than 0.03, as a more preferable example, greater than 0.015 and less than 0.03, as a still more preferable example, greater than 0.012 and less than 0.03, as a most preferable example, greater than 0.015 and less than 0.03. Within this range,
10 colorability may be excellent.
[30] In the present invention, difference in refractive index between certain components refers to difference between the minimum refractive index and the maximum refractive index thereamong.
15 [31] In the present invention, the alkyl (meth)acrylate includes an alkyl acrylate and an alkyl methacrylate. [32] In the present invention, the alkyl acrylate may be, for example, an alkyl acrylate containing an alkyl group having 1 to 15 carbon atoms and, as a specific example, may
20 include one or more selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylbutyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, heptyl acrylate, n-pentyl acrylate, and lauryl acrylate, preferably an alkyl
25 acrylate containing an alkyl group having 1 to 4 carbon
9

atoms, more preferably butyl acrylate.
[33] In the present invention, the alkyl methacrylate may be, for example, an alkyl methacrylate containing an alkyl group having 1 to 15 carbon atoms and, as a specific 5 example, may include one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylbutyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate, preferably an alkyl methacrylate containing an alkyl group having 1 to 4 carbon
10 atoms, more preferably methyl methacrylate.
[34] In the present invention, a polymer including a certain compound refers to a polymer prepared by polymerizing the compound, and one unit in the polymerized polymer is derived from the compound.
15 [35] For example, based on 100 parts by weight in total of monomers used to prepare a graft copolymer, the rubber core may include 0.01 to 3 parts by weight, preferably 0.1 to 1 part by weight of a crosslinking agent. Within this range, the impact resistance and weather resistance of a
20 resin may be improved.
[36] As a specific example, based on 100 parts by weight in total of monomers used to prepare a graft copolymer, the rubber core may be prepared by adding 0.01 to 3 parts by weight of a crosslinking agent, 0.01 to 3 parts by weight of
25 an initiator, and 0.01 to 5 parts by weight of an emulsifier
10

and performing polymerization. Within this range, the impact resistance and weather resistance of a resin may be improved.
[37] For example, the rubber core may include a polymer 5 seed.
[38] For example, based on 100 parts by weight in total of monomers used to prepare a graft copolymer, the polymer seed may include 1 to 30 parts by weight, preferably 3 to 20 parts by weight, more preferably 4 to 15 parts by weight of
10 one or more monomers selected from an alkyl acrylate and an alkyl methacrylate. Within this range, impact resistance, weather resistance, and physical property balance may be excellent. [39] For example, based on 100 % by weight in total of
15 monomers used to prepare a seed, the polymer seed may include 0 to 30 % by weight, preferably 1 to 20 % by weight, more preferably 3 to 10 % by weight of an alkyl methacrylate monomer. Within this range, impact resistance, weather resistance, and physical property balance may be excellent.
20 [40] For example, based on 100 % by weight in total of monomers used to prepare a seed, the polymer seed may include 0 to 20 % by weight of the aromatic vinyl compound and 0 to 10 % by weight of the vinyl cyanide compound, or may include 0.1 to 20 % by weight of the aromatic vinyl
25 compound and 0.1 to 10 % by weight of the vinyl cyanide
11

compound. As an example, the polymer seed may include 0.1 to 10 % by weight of the aromatic vinyl compound and 0.1 to 5 % by weight of the vinyl cyanide compound. Within this range, appearance properties may be improved. 5 [41] As a preferred example, the polymer seed may not
include an aromatic vinyl compound, a vinyl cyanide compound, or both.
[42] As a specific example, based on 100 parts by weight in total of monomers used to prepare a graft copolymer, the
10 polymer seed may be prepared by polymerizing 0.01 to 3 parts by weight of a crosslinking agent, 0.01 to 3 parts by weight of an initiator, and 0.01 to 5 parts by weight of an emulsifier. Within this range, polymers having a uniform size may be prepared within a short time, and the physical
15 properties of the polymers, such as weather resistance and impact resistance, may be further improved.
[43] As another specific example, based on 100 parts by weight in total of monomers used to prepare a graft copolymer, the polymer seed may be prepared by polymerizing
20 0.1 to 1 part by weight of a crosslinking agent, 0.01 to 1 part by weight of an initiator, and 0.5 to 1.5 parts by weight of an emulsifier. Within this range, polymers having a uniform size may be prepared within a short time, and the physical properties of the polymers, such as weather
25 resistance and impact resistance, may be further improved.
12

[44] Preferably, the polymer seed is prepared by polymerizing an alkyl acrylate alone or by copolymerizing an alkyl acrylate and an alkyl methacrylate. When necessary, an aromatic vinyl compound and/or a vinyl cyanide compound 5 may be additionally used when preparing the polymer seed. In this case, weather resistance and mechanical strength may be further improved.
[45] For example, the polymer seed may have an average particle diameter of 10 to 60 nm, preferably 30 to 60 nm,
10 more preferably 30 to 50 nm, most preferably 30 to 40 nm. Within this range, weather resistance and colorability may be excellent.
[46] When preparing the polymer seed, one or more of an electrolyte and a grafting agent may be optionally included.
15 [47] For example, based on 100 parts by weight in total of monomers used to prepare a graft copolymer, the electrolyte may be included in an amount of 0.005 to 1 part by weight, 0.01 to 1 part by weight, or 0.05 to 1 part by weight. Within this range, polymerization efficiency and
20 latex stability may be improved.
[48] In the present invention, the electrolyte may include, for example, one or more selected from the group consisting of KCl, NaCl, KHCO3, NaHCO3, K2CO3, Na2CO3, KHSO3, NaHSO3, K4P2O7, Na4P2O7, K3PO4, Na3PO4, K2HPO4, Na2HPO4, KOH,
25 NaOH, and Na2S2O7, without being limited thereto.
13

[49] For example, based on 100 parts by weight in total of monomers used to prepare a graft copolymer, the grafting agent may be included in an amount of 0.01 to 3 parts by weight, 0.01 to 1 part by weight, or 0.01 to 0.5 parts by 5 weight. Within this range, the grafting degree of a graft polymer may be improved, and other physical properties may be improved.
[50] In the present invention, unless otherwise defined, grafting agents commonly used in the art to which the
10 present invention pertains may be used as the grafting agent of the present invention, without particular limitation. For example, a compound including two or more unsaturated vinyl groups having different reactivities may be used as the grafting agent. For example, one or more selected from
15 allyl methacrylate, triallyl isocyanurate, triallyl amine,
and diallyl amine may be used, without being limited thereto. [51] In the present invention, the (co)polymer may include a polymer and a copolymer. [52] For example, an alkyl methacrylate included in the
20 (co)polymer shell may be included in an amount of 65 to 100 % by weight, preferably 80 to 99.5 % by weight, more preferably 85 to 95 % by weight in the (co)polymer shell. Within this range, impact strength and weather resistance may be excellent.
25 [53] For example, the (co)polymer shell may further
14

include an alkyl acrylate. In this case, impact strength may be excellent.
[54] For example, an alkyl acrylate included in the (co)polymer shell may be included in an amount of 0.1 to 5 20 % by weight, preferably 5 to 15 % by weight in the (co)polymer shell. Within this range, impact strength may be excellent.
[55] When necessary, the (co)polymer shell may further include one or more selected from the group consisting of
10 aromatic vinyl compounds and vinyl cyanide compounds. In this case, impact strength may be improved.
[56] For example, difference in refractive index between the (co)polymer shell and the matrix resin may be 0.005 or less, preferably less than 0.005, more preferably 0.003 or
15 less, still more preferably 0.0025 or less, most preferably 0.0021 or less. Within this range, colorability may be excellent.
[57] For example, based on 100 % by weight in total of monomers used to prepare a shell, the (co)polymer shell may
20 include 0 to 10 % by weight of the aromatic vinyl compound and 0 to 5 % by weight of the vinyl cyanide compound, preferably 0.1 to 10 % by weight of the aromatic vinyl compound and 0.1 to 5 % by weight of the vinyl cyanide compound, more preferably 0.1 to 5 % by weight of the
25 aromatic vinyl compound and 0.1 to 2.5 % by weight of the
15

vinyl cyanide compound. Within this range, appearance properties may be excellent.
[58] In the present invention, the aromatic vinyl compound may include, for example, one or more selected from 5 styrene, α-methylstyrene, p-methylstyrene, and vinyl toluene, preferably styrene, without being limited thereto.
[59] In the present invention, the vinyl cyanide compound may include, for example, one or more selected from acrylonitrile, methacrylonitrile, and ethacrylonitrile,
10 preferably acrylonitrile, without being limited thereto.
[60] Emulsifiers commonly used in the art to which the present invention pertains may be used as the emulsifier of the present invention without particular limitation. For example, the emulsifier may include one or more selected
15 from the group consisting of low molecular weight carboxylates having 20 or fewer carbon atoms or 10 to 20 carbon atoms, such as rosinates, laurates, oleic acid salts, and stearates; alkyl sulfosuccinates having 20 or fewer carbon atoms or 10 to 20 carbon atoms or derivatives
20 thereof; alkyl sulfates having 20 or fewer carbon atoms or 10 to 20 carbon atoms or sulfonates; polyfunctional carboxylic acids having 20 to 60 carbon atoms, 20 to 55 carbon atoms, or 30 to 55 carbon atoms and having two or more carboxyl groups, preferably 2 to 3 carboxyl groups or
25 salts thereof; and one or more phosphoric acid salts
16

selected from the group consisting of mono-alkyl ether phosphate and dialkyl ether phosphate.
[61] As another example, the emulsifier may include one or more selected from the group consisting of reactive 5 emulsifiers selected from sulfoethyl methacrylate, 2-acrylamido-2-methylpropane sulfonic acid, sodium styrene sulfonate, sodium dodecyl allyl sulfosuccinate, a copolymer of styrene and sodium dodecyl allyl sulfosuccinate, polyoxyethylene alkylphenyl ether ammonium sulfate, alkenyl
10 C16-18 succinic acid di-potassium salt, and sodium methallyl sulfonate; and non-reactive emulsifiers selected from the group consisting of alkyl aryl sulfonates, alkali methyl alkyl sulfates, sulfonated alkylesters, fatty soap, and alkali salts of rosin acid.
15 [62] In the present invention, the monomers refer to an alkyl acrylate, an alkyl methacrylate, an aromatic vinyl compound, and a vinyl cyanide compound.
[63]
[64] For example, the graft copolymer (A) may have a 20 grafting degree of 20 to 100 %, preferably 30 to 80 %, more
preferably 40 to 70 %. Within this range, appearance
properties, such as colorability, and impact resistance may
be excellent.
[65] As a specific example, based on 100 parts by weight 25 in total of monomers used to prepare a graft copolymer, the
17

(co)polymer shell may be prepared by adding 20 to 80 parts by weight of an alkyl methacrylate, 0.01 to 5 parts by weight of an emulsifier, and 0.01 to 3 parts by weight of an initiator and performing graft polymerization. Within this 5 range, weather resistance and impact resistance may be excellent.
[66]
[67] Optionally, the (co)polymer shell may further
include a molecular weight modifier. For example, based on
10 100 parts by weight in total of monomers used to prepare a graft copolymer, the molecular weight modifier may be included in an amount of 0.01 to 2 parts by weight, 0.05 to 2 parts by weight, or 0.05 to 1 part by weight. Within this range, a polymer having a desired size may be easily
15 prepared.
[68] In the present invention, "based on 100 parts by weight in total of monomers used to prepare a graft copolymer" means that a total weight of monomers used to prepare a seed, a core, and a shell constituting a graft
20 copolymer is regarded as 100 parts by weight, and may be referred to as "based on 100 parts by weight in total of a graft copolymer" or "based on 100 parts by weight of a sum of a rubber core and monomers". [69] For example, the molecular weight modifier may
25 include one or more selected from the group consisting of
18

mercaptans such as α-methylstyrene dimer, t-dodecyl mercaptan, n-dodecyl mercaptan, and octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, and methylene bromide; and sulfur-5 containing compounds such as tetraethylthiuram disulfide, dipentamethylene thiuram disulfide, and diisopropylxanthogen disulfide, preferably mercaptan compounds such as tert-dodecyl mercaptan, without being limited thereto. [70] In the present invention, unless otherwise defined,
10 crosslinking agents commonly used in the art to which the present invention pertains may be used as the crosslinking agent of the present invention without particular limitation. For example, the crosslinking agent may include acrylic compounds that contain an unsaturated vinyl group and may
15 serve as a crosslinking agent. As a specific example, the crosslinking agent may include one or more selected form the group consisting of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, ethylene
20 glycol diacrylate, ethylene glycol dimethacrylate,
divinylbenzene, diethylene glycol dimethacrylate,
triethylene glycol dimethacrylate, 1,3-butadiol
dimethacrylate, hexanediol propoxylate diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol ethoxylate
25 diacrylate, neopentyl glycol propoxylate diacrylate,
19

trimethylolpropane trimethacrylate, trimethylolmethane triacrylate, trimethylpropane ethoxylate triacrylate, trimethylpropane propoxylate triacrylate, pentaerythritol ethoxylate triacrylate, pentaerythritol propoxylate 5 triacrylate, and vinyltrimethoxysilane, without being limited thereto.
[71] In the present invention, initiators commonly used in the art to which the present invention pertains may be used as the initiator of the present invention without
10 particular limitation. For example, the initiator may include water-soluble initiators, oil-soluble initiators, or mixtures thereof.
[72] For example, the water-soluble initiator may include one or more selected from the group consisting of
15 sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide, without being limited thereto.
[73] For example, the oil-soluble initiator may include one or more selected from the group consisting of t-butyl
20 peroxide, cumene hydroperoxide, p-methane hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide, diisopropylbenzene hydroperoxide, 3,5,5-trimethylhexanol peroxide, t-butyl peroxy isobutyrate, azobisisobutyronitrile,
25 azobis-2,4-dimethylvaleronitrile,
20

azobiscyclohexanecarbonitrile, and azobis(isobutyric acid methyl), without being limited thereto.
[74] In one or more of a step of preparing a polymer seed, a step of preparing a rubber core, and a step of 5 preparing a (co)polymer shell according to the present invention, in addition to the above-described initiator, an activator is preferably included to further activate initiation reaction. More preferably, the activator is included in the step of preparing a (co)polymer shell.
10 [75] The activator preferably includes one or more selected from the group consisting of sulfinato acetic acid metal salts and sulfonato acetic acid metal salts. In this case, weather resistance and colorability may be significantly improved while maintaining impact strength.
15 [76] For example, the metal salt may be an alkali metal salt, preferably a sodium salt. In this case, weather resistance and colorability may be significantly improved while maintaining impact strength. [77] Preferably, the sulfinato acetic acid metal salt
20 and the sulfonato acetic acid metal salt may each independently include one or more functional groups, and the functional groups preferably include a hydroxyl group. In this case, weather resistance and colorability may be significantly improved while maintaining impact strength.
25 [78] As a specific example, the sulfinato acetic acid
21

metal salts including a hydroxyl group as the functional
group may include disodium 2-hydroxy-2-sulfinatoacetate, and
the sulfonato acetic acid metal salts including a hydroxyl
group as the functional group may include disodium 2-
5 hydroxy-2-sulfonatoacetate. In this case, weather
resistance and colorability may be significantly improved
while maintaining impact strength.
[79]
[80] Preferably, the activator includes a compound 10 represented by Chemical Formula 1 below. [81] [Chemical Formula 1]

[83] In Chemical Formula 1, R1 and R2 are the same or different from each other. R1 and R2 are each independently
15 hydrogen, a C1 to C10 alkyl group, or -(C=O)OM2, but both R1 and R2 are not hydrogen. M1 and M2 are the same or different from each other, and are each independently alkali metals. [84] When the compound represented by Chemical Formula 1 is used, the grafting degree of a graft copolymer may be
20 significantly increased, thereby improving appearance
22

properties including colorability.
[85] In addition, in the case of the compound represented by Chemical Formula 1, although dextrose or sodium formaldehyde sulfoxylate as a conventional reducing 5 agent is not used, and a compound containing a divalent iron ion, such as iron sulfate, as a conventional activator and sodium pyrophosphate or sodium ethylenediamine tetraacetate as a conventional chelating agent are used in small amounts compared to a conventional method, the high grafting degree
10 of a graft copolymer may be secured. In particular, since dextrose, which is a reducing agent, is a material that is easily discolored, excellent weather resistance may be secured by removing dextrose. [86] In Chemical Formula 1, M1 and M2 are the same or
15 different from each other, and are each independently Na or K, preferably Na.
[87] Chemical Formula 1, preferably, R1 and R2 are the same or different from each other, and R1 and R2 are each independently hydrogen or -(C=O)OM2.
20 [88] When the above conditions are satisfied, the grafting degree of a graft copolymer may be significantly increased, thereby improving appearance properties, such as colorability, and securing weather resistance. [89] Preferably, the activator includes a compound
25 represented by Chemical Formula 2 below.
23

[90] [Chemical Formula 2]

[92] Preferably, the activator according to the present invention is continuously fed for a certain period of time 5 to maintain excellent activity and improve the grafting degree of a graft copolymer. In addition, to achieve continuous feeding, the activator preferably is fed after being mixed with a solvent. In this case, the solvent may be, for example, water.
10 [93] In the present invention, "continuous feeding" is
distinguished from "batch feeding". For example,
"continuous feeding" means that, during polymerization reaction, feeding is performed for 10 minutes or more, 30 minutes or more, or 1 hour or more, preferably 2 hours or
15 more in a dropwise manner, a little-by-little manner, a step-by-step manner, or a continuous flow manner.
[94] Based on 100 parts by weight in total of monomers fed when preparing the graft copolymer, the activator may be fed in an amount of 0.01 to 1 part by weight or 0.1 to 0.8
20 parts by weight. Within this range, grafting degree may be
24

significantly increased, thereby improving colorability and appearance properties.
[95] In a preparation step performed by including the activator, one or more selected from the group consisting of 5 compounds including divalent iron ions and chelating agents are preferably included.
[96] In addition, to stably impart catalytic activity to a polymerization initiator, a compound including a divalent iron ion such as ferrous sulfate may be included in, for
10 example, 0.0001 to 0.01 parts by weight based on 100 parts by weight in total of monomers used to prepare a graft copolymer, and chelating agents including sodium pyrophosphate and/or sodium ethylenediamine tetraacetate may be included in, for example, 0.001 to 0.1 parts by weight
15 based on 100 parts by weight in total of monomers used to
prepare a graft copolymer. Within this range,
polymerization initiation may be further accelerated, and the weather resistance of a prepared polymer may be improved. [97] For example, in the step of preparing a graft
20 copolymer according to the present invention, a conventional reducing agent such as dextrose may not be used. In this case, weather resistance may be improved.
[98] For example, graft copolymer latex obtained through the step of preparing a rubber core and a (co)polymer shell
25 may have a coagulum content of 1 % or less, preferably 0.5 %
25

or less, more preferably 0.1 % or less. Within this range, the productivity of a resin, mechanical strength, and appearance properties may be improved.
[99] In the present invention, the weight of coagulum 5 generated in a reactor, the total weight of rubber, and the weight of monomers are measured, and coagulum content (%) may be calculated by substituting the measured values into Equation 1 below. [100] [Equation 1]
10 [101] Solid coagulum (%) = (Weight of coagulum generated in reactor (g)/total weight of rubber and monomers (g)) × 100
[102] The graft copolymer latex may be prepared in a powder form through conventional processes including
15 coagulation, washing, drying, and the like. For example, to prepare the graft copolymer latex in a powder form, a metal salt or an acid may be added to the graft copolymer latex, and then coagulation may be performed at 60 to 100 °C, followed by aging, dehydration, washing, and drying.
20 However, the present invention is not limited thereto.
[103] For example, the present invention may include a method of preparing a graft copolymer, the method including a core preparation step of preparing a rubber core by adding and polymerizing a monomer including an alkyl
25 (meth)acrylate; and a shell preparation step of preparing a
26

shell by adding and graft-polymerizing an emulsifier and a monomer including an alkyl methacrylate compound in the presence of the prepared rubber core. The method may also be defined with or limited to the above description. 5 [104] As another example, the present invention may include a method of preparing a graft copolymer, the method including a seed preparation step (a) of preparing a polymer seed by polymerizing a monomer including an alkyl (meth)acrylate; a core preparation step (b) of preparing a
10 rubber core by adding and polymerizing a monomer including an alkyl (meth)acrylate in the presence of the prepared polymer seed; and a shell preparation step (c) of preparing a shell by adding and graft-polymerizing an emulsifier and a monomer including an alkyl methacrylate in the presence of
15 the prepared rubber core. The method may also be defined with or limited to the above description.
[105] Other conditions not specified in the method for preparing the graft copolymer described above, that is, polymerization conversion rate, reaction pressure, reaction
20 time, gel content, and the like are particularly limited when these conditions are within ranges commonly used in the technical field. Also, these conditions may be selectively performed as needed. [106] B) Matrix resin
25 [107] A matrix resin according to the present invention
27

is a thermoplastic resin that serves to impart excellent colorability by lowering refractive index.
[108] The matrix resin preferably includes a poly(alkyl
methacrylate) resin, more preferably a
5 polymethylmethacrylate resin. In this case, excellent weather resistance and appearance properties may be secured. [109] For example, the poly(alkyl methacrylate) resin may further include an alkyl acrylate. In this case, impact resistance may be excellent.
10 [110] For example, the alkyl acrylate may be included in an amount of 0.1 to 20 % by weight, preferably 1 to 15 % by weight, more preferably 1 to 10 % by weight in the poly(alkyl methacrylate) resin. Within this range, impact resistance may be excellent.
15 [111] For example, the matrix resin may have a weight average molecular weight of 50,000 to 200,000 g/mol, preferably 80,000 to 150,000 g/mol, more preferably 90,000 to 130,000 g/mol. Within this range, gloss, processability, and weather resistance may be excellent.
20 [112] In the present invention, unless otherwise defined, weight average molecular weight may be measured using gel permeation chromatography (GPC, Waters Breeze). As a specific example, weight average molecular weight may be measured using tetrahydrofuran (THF) as an eluate through
25 gel permeation chromatography (GPC, Waters Breeze). In this
28

case, weight average molecular weight is obtained as a relative value to a standard polystyrene (PS) specimen. [113] For example, the poly(alkyl methacrylate) resin may be prepared by mixing a crosslinking agent, an initiator, 5 and a monomer including an alkyl methacrylate and then performing bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization, preferably suspension polymerization or emulsion polymerization.
10 [114] Initiators commonly used to prepare a poly(alkyl methacrylate) resin may be used as the initiator of the present invention without particular limitation. For example, an azo initiator such as 2,2'-azobis 2'4-dimethyl-valeronitrile is preferably used as the initiator.
15 [115] When necessary, substances required for reaction, such as solvents and emulsifiers, and conditions, such as polymerization temperature and polymerization time, which should be added or changed depending on the above-described polymerization methods, may be appropriately selected
20 according to a polymerization method used to prepare a poly(alkyl methacrylate) resin, without particular limitation.
[116] C) Thermoplastic resin composition [117] For example, the thermoplastic resin composition of
25 the present invention may include 20 to 80 % by weight of
29

the graft copolymer and 20 to 80 % by weight of the matrix resin, preferably 30 to 70 % by weight of the graft copolymer and 30 to 70 % by weight of the matrix resin, most preferably 40 to 60 % by weight of the graft copolymer and 5 40 to 60 % by weight of the matrix resin. Within this range, colorability, impact resistance, and weather resistance may be excellent.
[118] For example, the thermoplastic resin composition may have a refractive index of greater than 1.46 and less
10 than 1.49, 1.47 or more and less than 1.488, or greater than 1.47 and less than 1.488, preferably greater than 1.46 and 1.485 or less, more preferably greater than 1.46 and less than 1.485, most preferably greater than 1.46 and 1.48 or less. Within this range, the thermoplastic resin
15 composition may have an advantage in expressing a deep black color due to excellent colorability.
[119] For example, based on 100 parts by weight in total of the graft copolymer and the matrix resin, the thermoplastic resin composition may include an alkyl
20 acrylate-aromatic vinyl compound-vinyl cyanide compound copolymer in an amount of 0 to 10 parts by weight, preferably 1 to 10 parts by weight, more preferably 1 to 5 parts by weight. Within this range, impact strength and processability may be significantly improved.
25 [120] For example, the alkyl acrylate-aromatic vinyl
30

compound-vinyl cyanide compound copolymer may be a copolymer prepared by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound onto alkyl acrylate rubber having an average particle size of 100 to 500 nm. Within 5 this range, gloss and processability may be excellent.
[121] As a more specific example, the alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound copolymer may be a copolymer prepared by graft-polymerizing 30 to 60 % by weight of an aromatic vinyl compound and 10 to 20 % by
10 weight of a vinyl cyanide compound onto 20 to 60 % by weight of alkyl acrylate rubber having an average particle size of greater than 100 nm and 500 nm or less. Within this range, gloss and processability may be excellent. [122] As another example, the alkyl acrylate-aromatic
15 vinyl compound-vinyl cyanide compound copolymer may be a copolymer prepared by graft-polymerizing 30 to 50 % by weight of an aromatic vinyl compound and 10 to 15 % by weight of a vinyl cyanide compound onto 40 to 60 % by weight of alkyl acrylate rubber having an average particle size of
20 200 to 400 nm. Within this range, gloss and processability may be excellent.
[123] The method of preparing the thermoplastic resin composition of the present invention includes a step of mixing and extruding the thermoplastic resin composition of
25 the present invention. In this case, impact strength may be
31

good, and weather resistance may be excellent. In particular, the thermoplastic resin composition may have an advantage in expressing a deep black color due to excellent colorability. 5 [124] For example, the extruding step may be performed at 190 to 260 °C and 100 to 300 rpm, preferably at 200 to 240 °C and 150 to 200 rpm. Within this range, a thermoplastic resin composition having excellent processability and desired physical properties may be
10 prepared.
[125] In the method of preparing the thermoplastic resin composition, when mixed, one or more additives selected from the group consisting of a flame retardant, a lubricant, an antibacterial agent, a release agent, a nucleating agent, a
15 plasticizer, a heat stabilizer, an antioxidant, a light stabilizer, a pigment, a dye, and a compatibilizer may be further included. Based on 100 parts by weight in total of a composition including a graft copolymer and a matrix resin, the additives are preferably included in an amount of 0.1 to
20 10 parts by weight, more preferably 1 to 7 parts by weight, most preferably 1 to 5 parts by weight. Within this range, the desired effect of the additives may be fully expressed without deterioration in the inherent physical properties of a resin.
25 [126] For example, the lubricant may be selected from
32

ethylene bis stearamide, oxidized polyethylene wax, metallic stearates, and various silicone oils, and may be used in an amount of 0.1 to 5 parts by weight, more preferably 0.1 to 2 parts by weight based on 100 parts by weight in total of a 5 composition including a graft copolymer and a matrix resin. [127] D) Molded article
[128] A molded article of the present invention is manufactured using the thermoplastic resin composition of the present invention. In this case, impact strength may be
10 good, and weather resistance may be excellent. In particular, the molded article may have an advantage in expressing a deep black color due to excellent colorability. [129] The molded article is preferably an automotive exterior material, more preferably an unpainted product,
15 such as a filler, or a lamp housing. In this case, impact strength, weather resistance, and colorability required by the molded article may be achieved.
[130] For example, the present invention may include a method of manufacturing a molded article, the method
20 including a step of injecting the thermoplastic resin composition of the present invention or the pellet thereof. [131] For example, the injection step may be performed at 190 to 260 °C and 30 to 80 bar, preferably at 200 to 240 °C and 40 to 60 bar. Within this range, processability may be
25 improved, and the desired levels of impact strength, weather
33

resistance, and colorability may be achieved.
[132] For example, the molded article may have a blackness (L value) of less than 25.0, preferably 24.5 or less, more preferably 24.0 or less, as a preferred example, 5 24.5 to 20, as a more preferred example, 24 to 22. Within this range, overall physical property balance and colorability may be excellent.
[133] Other conditions not specified in the thermoplastic resin composition and the molded article described above are
10 particularly limited when these conditions are within ranges commonly used in the art to which the preset invention pertains. Also, these conditions may be appropriately selected as needed. [134] Hereinafter, the present invention will be
15 described in more detail with reference to the following preferred examples. However, these examples are provided for illustrative purposes only and should not be construed as limiting the scope and spirit of the present invention. In addition, it will be apparent to those skilled in the art
20 that various changes and modifications may be made without
departing from the spirit and scope of the present invention, and such changes and modifications are also within the scope of the appended claims. [135] [Examples]
25 [136] Example 1
34

[137]
[138] 5 parts by weight of butyl acrylate, 1.4 parts by weight of sodium dodecyl sulfate, 0.05 parts by weight of ethylene glycol dimethacrylate, 0.05 parts by weight of 5 allyl methacrylate, 0.1 parts by weight of potassium hydroxide, and 60 parts by weight of distilled water were fed into a nitrogen-substituted reactor batchwise, temperature was raised to 70 °C, 0.05 parts by weight of potassium persulfate was added to initiate reaction, and
10 then polymerization was performed for 1 hour. The average particle diameter of a rubber polymer seed obtained after reaction was 45 nm, and the refractive index thereof was 1.46. [139]
15 [140] A mixture obtained by adding 45 parts by weight of butyl acrylate, 0.7 parts by weight of sodium dodecyl sulfate, 0.2 parts by weight of ethylene glycol dimethacrylate, 0.2 parts by weight of allyl methacrylate, 35 parts by weight of distilled water, and 0.1 parts by
20 weight of potassium persulfate to the polymer seed was continuously fed into a reactor at 70 °C for 2.0 hours. After feeding, polymerization was further performed for 1 hour. The average particle diameter of a rubber polymer obtained after reaction was 100 nm, and the refractive index
25 thereof was 1.46.
35

[141]
[142] Polymerization was performed while continuously feeding a mixture obtained by uniformly mixing 23 parts by weight of distilled water, 45 parts by weight of methyl 5 methacrylate, 5 parts by weight of butyl acrylate, 1.5 parts by weight of potassium rosinate as an emulsifier, 0.1 parts by weight of n-octyl mercaptan, and 0.1 parts by weight of cumene hydroperoxide as an initiator; an aqueous solution (concentration: 5 % by weight) containing 0.3 parts by
10 weight of 2-hydroxy-2-sulfinato acetic acid disodium salt as an activator; and a mixed liquid containing 0.03 parts by weight of pyrophosphoric acid sodium and 0.0006 parts by weight of ferrous sulfide into the reactor containing the obtained core at 75 °C for 3 hours. After completion of
15 continuous feeding, polymerization was further performed at 75 °C for 1 hour, followed by cooling to 60 °C to terminate polymerization and obtain a graft copolymer latex. The average particle diameter of the graft copolymer obtained after reaction was 125 nm, and the shell refractive index
20 thereof was 1.487. In addition, the total refractive index of the graft copolymer was 1.4735, and the grafting degree thereof was 70 %.
[143] < Preparation of graft copolymer powder > [144] 1.0 part by weight of an aqueous solution
25 containing calcium chloride was applied to the prepared
36

(meth)acrylate graft copolymer latex, coagulation was performed at 60 to 85 °C under atmospheric pressure, aging was performed at 70 to 95 °C, dehydration and washing were performed, and then drying was performed with 80 °C hot 5 blast for 2 hours to prepare a graft copolymer powder. [145]
[146] 95 parts by weight of methyl methacrylate, 5 parts by weight of methyl acrylate, 200 parts by weight of distilled water, 0.3 parts by weight of polyvinyl alcohol as
10 a suspension agent, and 0.3 parts by weight of n-octyl mercaptan were fed batchwise into a nitrogen-substituted reactor, the internal temperature of the reactor was raised to 80 °C, 0.1 parts by weight of AIBN as an initiator was added thereto to initiate reaction, polymerization was
15 performed for 70 minutes while maintaining the internal temperature of the reactor at 80 °C, and then the temperature of the reactor was raised to 110 °C for 30 minutes to perform additional polymerization. The polymerized beads were washed using a dehydrator and dried
20 in a fluid bed dryer at 80 °C for 2 hours. The molecular weight of the prepared polymethylmethacrylate resin was 120,000 g/mol, and the refractive index thereof was 1.487. [147] [148] 50 parts by weight of the graft copolymer powder,
25 50 parts by weight of the polymethylmethacrylate resin, 1.5

parts by weight of a lubricant, 1.0 part by weight of an antioxidant, 1.0 part by weight of an ultraviolet light stabilizer, and 1 part by weight of a black colorant were added and mixed. This mixture was prepared in a pellet form 5 using a 36 pi extrusion kneader at a cylinder temperature of 220 °C, and the pellet was injected to prepare a specimen for measuring physical properties. At this time, the refractive index of an entire thermoplastic resin composition was 1.4813. In addition, difference between the
10 refractive index of a shell and a matrix resin and the refractive index of rubber was 0.027, and difference in refractive index between the shell and the matrix resin was 0.0021. [149] Example 2
15 [150] The preparation process was performed in the same manner as in Example 1, except that, in the seed preparation step, 4.5 parts by weight of butyl acrylate and 0.5 parts by weight of methyl methacrylate were used instead of 5 parts by weight of butyl acrylate, and 1.6 parts by weight of
20 sodium dodecyl sulfate was used; and 40.5 parts by weight of butyl acrylate and 4.5 parts by weight of methyl methacrylate were used instead of 45 parts by weight of butyl acrylate in the core preparation step. In this case, the grafting degree of a graft copolymer was 58 %, the
25 refractive index of rubber was 1.463, and the refractive

【CLAIMS】
【Claim 1】
A thermoplastic resin composition, comprising:
5 a graft copolymer (A) containing an alkyl
(meth)acrylate rubber core and an alkyl methacrylate compound (co)polymer shell surrounding the alkyl acrylate rubber core; and
a matrix resin (B),
10 wherein the rubber core has an average particle
diameter of 40 to 120 nm,
the graft copolymer (A) has a grafting degree of 20 to 100 %,
difference in refractive index between the rubber core, 15 the (co)polymer shell, and the matrix resin is less than 0.04, and
the thermoplastic resin composition has a refractive index of greater than 1.46 and less than 1.49 and a blackness (L value) of less than 25.0. 20
【Claim 2】
The thermoplastic resin composition according to claim 1, wherein the matrix resin comprises a poly(alkyl methacrylate) resin. 25

【Claim 3】
The thermoplastic resin composition according to claim
2, wherein the poly(alkyl methacrylate) resin further
comprises alkyl acrylate.
5
【Claim 4】
The thermoplastic resin composition according to claim
3, wherein the alkyl acrylate is comprised in an amount of
0.1 to 20 % by weight in the poly(alkyl methacrylate) resin.
10
【Claim 5】
The thermoplastic resin composition according to claim
1, wherein the rubber core further comprises an alkyl
methacrylate. 15
【Claim 6】
The thermoplastic resin composition according to claim
5, wherein the alkyl methacrylate is comprised in an amount
of 0.1 to 30 % by weight in the rubber core. 20
【Claim 7】
The thermoplastic resin composition according to claim
1, wherein the rubber core further comprises one or more
selected from the group consisting of aromatic vinyl 25 compounds and vinyl cyanide compounds.

【Claim 8】
The thermoplastic resin composition according to claim 1, wherein the (co)polymer shell further comprises an alkyl 5 acrylate.
【Claim 9】
The thermoplastic resin composition according to claim 8, wherein the alkyl acrylate is comprised in an amount of 10 0.1 to 20 % by weight in the (co)polymer shell.
【Claim 10】
The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition comprises 20 15 to 80 % by weight of the graft copolymer and 20 to 80 % by weight of the matrix resin.
【Claim 11】
The thermoplastic resin composition according to claim 20 1, wherein the thermoplastic resin composition further comprises an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound copolymer.
【Claim 12】

A molded article, comprising the thermoplastic resin composition of any one of claims 1 to 11.
[Claim 13]
A method of preparing a thermoplastic resin composition, the method comprising a step of mixing and extruding the thermoplastic resin composition of any one of claims 1 to 11.