Method for preparing graft copolymer, and resin composition comprising graft copolymer prepared thereby

Abstract

The present invention relates to: a method for preparing a graft copolymer by using a single type of conjugated diene-based polymer latex of a limited size and distribution in order to provide a resin composition with improved impact strength, tensile strength or flame retardancy; and a resin composition comprising same.

Description

Method for producing a graft copolymer and a resin composition comprising a graft copolymer produced thereby

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0107205, filed August 16, 2023, the entire disclosure of which is incorporated herein by reference.

[0003]

[0004] [Technical Field]

[0005] The present invention relates to a method for producing a graft copolymer and a resin composition comprising the graft copolymer produced thereby.

[0006] Graft copolymers, such as acrylonitrile-butadiene-styrene (ABS) copolymers, are manufactured by graft polymerizing vinyl cyanide monomers and vinyl aromatic monomers onto a diene rubber polymer. Compared to conventional high-impact polystyrene (HIPS), ABS copolymers exhibit superior impact resistance, chemical resistance, thermal stability, colorability, fatigue resistance, rigidity, and processability, and are used in automotive interior and exterior materials, office equipment, various electrical and electronic product components, and toys.

[0007] Meanwhile, the graft polymerization can be performed by adding an aromatic vinyl monomer and a vinyl cyan monomer to polybutadiene latex (PBL) and performing emulsion polymerization, and thus, the graft copolymer can be obtained in the form of latex.

[0008] The production of graft copolymer latex used in the production of a resin composition can be carried out by using two or more different types of PBLs. However, when graft copolymer latex produced using two or more different types of PBLs is used in the production of a resin composition, there has been a problem that the tensile strength of the produced resin composition is reduced. Therefore, recently, a method of producing graft copolymer latex used in the production of a resin composition using one type of PBL has been studied in order to improve the tensile strength of the resin composition.

[0009] However, when obtaining a graft copolymer latex using a single PBL, there is a problem in that it is difficult to secure excellent impact strength and uniform physical properties compared to when using two or more types of PBL.

[0010] [Prior Art Literature]

[0011] [Patent Document]

[0012] (Patent Document 0001) JP Registration No. 7005990 B2

[0013] The problem to be solved by the present invention is to provide a method for producing a graft copolymer for producing a resin composition having excellent tensile strength, impact strength, or flame retardancy.

[0014] Another problem to be solved by the present invention is to provide a resin composition having excellent tensile strength, impact strength, or flame retardancy.

[0015] (1) The present invention provides a method for producing a graft copolymer, comprising the steps of: (S1) obtaining a conjugated diene polymer latex comprising conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt% and a proportion of particles having a particle size of 150 nm or less of 10% or less; and (S2) introducing an aromatic vinyl monomer and a vinyl cyan monomer in the presence of the conjugated diene polymer latex and subjecting the mixture to graft polymerization to obtain a graft copolymer latex.

[0016] (2) The present invention provides a method for producing a graft copolymer in which the average particle diameter of the conjugated diene polymer particles in (1) above is 280 nm or more and 320 nm or less.

[0017] (3) The present invention provides a method for producing a graft copolymer, wherein in the above (1) or (2), the step S2 comprises: a first polymerization step (S2-1) of simultaneously introducing the conjugated diene polymer latex, an aromatic vinyl monomer, a vinyl cyan monomer, and a polymerization initiator; and a second polymerization step (S2-2) of continuously introducing the aromatic vinyl monomer, the vinyl cyan monomer, and an emulsifier after the first polymerization step (S2-1).

[0018] (4) The present invention provides a method for producing a graft copolymer, wherein no emulsifier is added in the first polymerization step (S2-1) in any one of the above (1) to (3).

[0019] (5) The present invention provides a method for producing a graft copolymer, wherein, in any one of (1) to (4), an emulsifier introduced in the second polymerization step (S2-2) is introduced in an amount of 0.4 parts by weight or more and 0.7 parts by weight or less, based on 100 parts by weight of the conjugated diene polymer latex, aromatic vinyl monomer, and vinyl cyan monomer introduced in the first polymerization step and the aromatic vinyl monomer and vinyl cyan monomer introduced in the second polymerization step.

[0020] (6) The present invention provides a method for producing a graft copolymer, wherein, in any one of (1) to (5), the average particle diameter of the conjugated diene polymer particles is smaller than the average particle diameter of the graft copolymer particles, and the average particle diameter of the graft copolymer particles is 300 nm or more and 350 nm or less.

[0021] (7) The present invention provides a method for producing a graft copolymer, wherein the average particle diameter of the conjugated diene polymer particles is smaller than the average particle diameter of the graft copolymer particles in any one of the above (1) to (6).

[0022] (8) The present invention provides a method for producing a graft copolymer, wherein the conjugated diene polymer particles have a gel content of 70 wt% or more and less than 80 wt%, and the proportion of particles having a particle size of 150 nm or less in the particle distribution is 9% or less, in any one of the above (1) to (7).

[0023] (9) The present invention provides a conjugated diene polymer latex comprising conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt%, and a proportion of particles having a particle size of 150 nm or less in the particle distribution of 10% or less.

[0024] (10) The present invention provides a conjugated diene polymer latex comprising conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt%, and a proportion of particles having a particle size of 150 nm or less in the particle distribution of (9) above of 9% or less.

[0025] (11) The present invention provides a graft copolymer manufactured by any one of the graft copolymer manufacturing methods among (1) to (7) above.

[0026] (12) The present invention provides a resin composition comprising the graft copolymer of (12).

[0027] According to the present invention, a graft copolymer for producing a resin composition having excellent tensile strength, impact strength, or flame retardancy can be produced.

[0028] In addition, a resin composition having excellent tensile strength, impact strength, or flame retardancy can be manufactured.

[0029] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0030] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0031] In the present invention, the term 'monomer unit' may refer to a component, structure, or substance itself derived from a monomer, and as a specific example, may refer to a repeating unit formed within a polymer by a monomer introduced during polymerization of the polymer and participating in the polymerization reaction.

[0032] In the present invention, the "weight average molecular weight" is measured by gel permeation chromatography (GPC). For example, the sample to be measured can be dissolved in a THF (tetrahydrofuran) solution, and then measured as a relative value to a standard sample (PS, standard polystyrene) through gel permeation chromatography (GPC).

[0033] The term 'composition' as used in the present invention includes a mixture of materials comprising the composition as well as reaction products and decomposition products formed from the materials of the composition.

[0034] In the present invention, the 'average particle diameter' may refer to the arithmetic mean particle diameter in the particle size distribution measured by dynamic light scattering, specifically, the scattering intensity average particle diameter. The average particle diameter of the conjugated diene polymer can be measured using the Nicomp N3000 equipment (product name, manufacturer: PSS Nicomp).

[0035] In the present invention, the term 'latex' may mean a polymer or copolymer polymerized by polymerization that exists in a form dispersed in water, and as a specific example, it may mean a polymer or copolymer of rubber polymerized by emulsion polymerization that exists in a form dispersed in water in a colloidal state.

[0036]

[0037] <Method for producing graft copolymer>

[0038] A method for producing a graft copolymer according to one embodiment of the present invention comprises the steps of: obtaining a conjugated diene polymer latex including conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt% and a proportion of particles having a particle size of 150 nm or less of 10% or less; and a step (S2) of introducing an aromatic vinyl monomer and a vinyl cyan monomer in the presence of the conjugated diene polymer latex and performing graft polymerization to produce a graft copolymer.

[0039]

[0040] The present inventors have confirmed that when a conjugated diene polymer satisfying a specific gel content, a specific average particle diameter, and a specific particle size distribution is used to prepare a graft copolymer for preparing a resin composition, the impact strength, tensile strength, and flame retardancy of the resin composition are simultaneously improved, and based on this, they have devoted themselves to further research and completed the present invention.

[0041]

[0042] Hereinafter, the method for producing a graft copolymer of the present invention will be described in detail step by step.

[0043]

[0044] 1) Step of obtaining a conjugated diene polymer latex

[0045]

[0046] In one embodiment of the present invention, a conjugated diene polymer latex used in the production of a graft copolymer can be obtained by polymerizing a conjugated diene monomer with an emulsifier, an electrolyte, and a molecular weight regulator.

[0047]

[0048] According to one embodiment of the present invention, the conjugated diene monomer for obtaining the conjugated diene polymer latex may be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, and 2-phenyl-1,3-butadiene, and a more specific example may be 1,3-butadiene. The conjugated diene polymer particles included in the conjugated diene polymer may include a conjugated diene monomer unit formed by the conjugated diene monomer.

[0049]

[0050] According to one embodiment of the present invention, the emulsifier may be at least one selected from the group consisting of potassium oleate, docusate sodium, allyl aryl sulfonate, alkali methyl alkyl sulfonate, sulfonated alkyl ester, fatty acid soap, and rosin acid alkali salt, and preferably, fatty acid soap and rosin acid alkali salt may be used in combination.

[0051]

[0052] According to one embodiment of the present invention, the electrolyte may be at least one selected from the group consisting of K2CO3, Na2SO4, Na3PO4, NaH2PO4 and Na2HPO4, preferably Na2SO4, Na3PO4 or a mixture thereof, and more preferably K2CO3.

[0053]

[0054] According to one embodiment of the present invention, the molecular weight regulator may be at least one selected from the group consisting of t-dodecyl mercaptan, n-dodecyl mercaptan, and α-methyl styrene dimer, and more preferably t-dodecyl mercaptan and α-methyl styrene dimer.

[0055]

[0056] The conjugated diene polymer particles included in the manufactured conjugated diene polymer latex may have a gel content of 70 wt% or more and less than 80 wt%. Specifically, the gel content of the conjugated diene polymer particles may be 71 wt% or more, 72 wt% or more, 73 wt% or more, or 74 wt% or more, and may be 79 wt% or less, 78 wt% or less, 77 wt% or less, or 76 wt% or less.

[0057] When the gel content of the conjugated diene polymer particles satisfies the above range, the tensile strength, impact strength, or flame retardancy of the resin composition manufactured using the conjugated diene polymer latex is improved. If the gel content of the conjugated diene polymer particles is less than the above range, the tensile strength and impact strength may decrease. In addition, when the gel content of the conjugated diene polymer particles exceeds the above range, the impact strength or flame retardancy of the resin composition manufactured using the conjugated diene polymer latex may decrease.

[0058] In the present invention, the method for calculating the gel content of the conjugated diene polymer particles included in the conjugated diene polymer latex is as follows. First, the conjugated diene polymer latex is coagulated using a dilute acid or a metal salt, then washed, and dried in a vacuum oven at 60°C for 24 hours to obtain conjugated diene polymer particles. The conjugated diene polymer particles are cut into small pieces with scissors to prepare 1 g of rubber segments, and the rubber segments are placed in 100 g of toluene and stored in a dark room at 23°C for 48 hours, after which the sol and gel are separated. The sol and gel are substituted into the following mathematical equation 1 to calculate the gel content. Here, the type of dilute acid is not particularly limited, but it is preferably at least one selected from the group consisting of hydrochloric acid, sulfuric acid, formic acid, and the like. In addition, the type of metal salt is not particularly limited, but it is preferable that it be at least one selected from the group consisting of magnesium sulfate, calcium chloride, and aluminum sulfate.

[0059]

[0060] [Mathematical Formula 1]

[0061] Gel content (wt%) = weight of gel / weight of rubber segment Х 100

[0062]

[0063] Meanwhile, when using a single type of conjugated diene polymer latex to manufacture graft copolymer latex, it has been common for the particle size distribution of conjugated diene polymer particles to have a large content ratio of particles with a particle size of 150 nm or less. However, when the content ratio of particles with a particle size of 150 nm or less is large, there has been a problem in that the impact efficiency of the resin composition being manufactured is significantly reduced.

[0064] The present invention uses a conjugated diene polymer latex in which the content of particles having a particle size of 150 nm or less among the particle size distribution of conjugated diene polymer particles is reduced, so that even if a graft copolymer used in the production of a resin composition is produced using one type of conjugated diene polymer latex, the impact efficiency of the produced resin composition is secured.

[0065] Specifically, according to one embodiment of the present invention, the content of particles having a particle diameter of 150 nm or less in the particle size distribution of the conjugated diene polymer particles included in the manufactured conjugated diene polymer latex may be 10% or less by weight. Preferably, the content of particles having a particle diameter of 150 nm or less in the particle size distribution of the conjugated diene polymer particles may be 9.5% or less, 9% or less, 8.5% or less, or 8% or less by weight.

[0066] When the content of particles having a particle size of 150 nm or less in the particle size distribution of the conjugated diene-based polymer particles satisfies the above range, the tensile strength, impact strength, or flame retardancy of a resin composition manufactured using the conjugated diene-based polymer latex may be improved. When the content of particles having a particle size of 150 nm or less in the particle size distribution of the conjugated diene-based polymer particles exceeds the above range, the tensile strength, impact strength, or flame retardancy of a resin composition manufactured using the conjugated diene-based polymer latex may be reduced.

[0067] In the present invention, the content of particles having a particle diameter of 150 nm or less among the particle size distribution of conjugated diene polymer particles included in the conjugated diene polymer latex can be calculated by measuring the particle distribution using CHDF 4000 equipment based on the principle of light dispersion.

[0068]

[0069] According to one embodiment of the present invention, the average particle diameter of the conjugated diene polymer particles included in the manufactured conjugated diene polymer latex may be 280 nm or more and 320 nm or less. Specifically, the average particle diameter of the conjugated diene polymer particles may be 285 nm or more, 290 nm or more, or 295 nm or more, and 315 nm or less, 310 nm or less, or 305 nm or less. When the average particle diameter of the conjugated diene polymer particles satisfies the above range, there is an effect of improving the tensile strength, impact strength, or flame retardancy of the resin composition manufactured using the conjugated diene polymer latex without deteriorating other physical properties. When the average particle diameter of the conjugated diene polymer particles exceeds the above range, the tensile strength or flame retardancy of the resin composition manufactured using the conjugated diene polymer latex may deteriorate.

[0070]

[0071] According to one embodiment of the present invention, the conjugated diene polymer latex used in the production of the graft copolymer may be one type of conjugated diene polymer latex having one gel content and one average particle size, rather than different types of conjugated diene polymer latex having different gel contents and / or average particle sizes. In the production of the graft copolymer, when one type of conjugated diene polymer latex is used, the tensile strength of the resulting resin composition may be improved compared to when different types of conjugated diene polymer latex are used.

[0072]

[0073] 2) Step of obtaining graft copolymer latex

[0074] A method for producing a graft copolymer according to one embodiment of the present invention can obtain a graft copolymer latex by introducing an aromatic vinyl monomer and a vinyl cyan monomer in the presence of a conjugated diene polymer latex produced as described above and performing graft polymerization.

[0075] Specifically, a method for producing a graft copolymer according to one embodiment of the present invention may include a 'first polymerization step' in which a portion of an aromatic vinyl monomer and a portion of a vinyl cyan monomer are introduced at once in the presence of a conjugated diene polymer latex to initiate a reaction, and a 'second polymerization step' in which a portion of an aromatic vinyl monomer and a portion of a vinyl cyan monomer are continuously introduced after the first polymerization step.

[0076] Below, each of the first polymerization step and the second polymerization step will be described in detail.

[0077]

[0078] 2-1) First polymerization stage

[0079] According to one embodiment of the present invention, in the first polymerization step, the conjugated diene polymer latex prepared above, an aromatic vinyl monomer, and a polymerization initiator are introduced in batches to initiate a reaction.

[0080] According to one embodiment of the present invention, the first polymerization step can be performed in a range of 45°C to 55°C.

[0081]

[0082] According to one embodiment of the present invention, the content (based on solid content) of the conjugated diene polymer latex introduced in batches in the first polymerization step may be 50 to 70 parts by weight, preferably 55 to 62 parts by weight, based on 100 parts by weight of the sum of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the impact resistance of the graft copolymer can be improved.

[0083]

[0084] According to one embodiment of the present invention, the aromatic vinyl monomer introduced in batches in the first polymerization step may be at least one selected from the group consisting of styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p-methylphenyl)styrene, and 1-vinyl-5-hexylnaphthalene, and a specific example thereof may be styrene.

[0085] According to one embodiment of the present invention, the content of the aromatic vinyl monomer introduced in batches in the first polymerization step may be 5 to 15 parts by weight, preferably 7 to 12 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the processability of the graft copolymer can be improved.

[0086]

[0087] According to one embodiment of the present invention, the vinyl cyan monomer introduced in batches in the first polymerization step may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile, and a specific example thereof may be acrylonitrile.

[0088] According to one embodiment of the present invention, the vinyl cyan monomer introduced in batches in the first polymerization step may be 1 to 5 parts by weight, preferably 2 to 3 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the chemical resistance of the graft copolymer can be improved.

[0089]

[0090] According to one embodiment of the present invention, the first polymerization step is performed in the presence of an initiator.

[0091] According to one embodiment of the present invention, the initiator may be at least one selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, hydroperoxide, t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide, 3,5,5-trimethylhexanol peroxide, t-butyl peroxy isobutyrate, azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile and azobisisobutyric acid (butyric acid) methyl, and among these Hydroperoxide is preferred.

[0092] According to one embodiment of the present invention, the initiator may be present in an amount of 0.01 to 1.0 parts by weight, preferably 0.02 to 0.08 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the polymerization stability of the graft polymerization can be improved, while the residual amount of the initiator in the graft copolymer can be minimized.

[0093]

[0094] According to one embodiment of the present invention, a reaction catalyst may be further added to promote the initiation reaction together with the initiator. The reaction catalyst may be at least one selected from the group consisting of sodium pyrrolate, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, dextrose, tetrasodium pyrophosphate, and sodium sulfate, and among these, at least one selected from the group consisting of dextrose, ferrous sulfate, and sodium pyrophosphate is preferred.

[0095] According to one embodiment of the present invention, the reaction catalyst may be added in a batch amount of 0.001 to 0.5 parts by weight, preferably 0.01 to 0.3 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the polymerization stability of the graft polymerization can be improved, while the residual amount of the reaction catalyst in the graft copolymer can be minimized.

[0096]

[0097] According to one embodiment of the present invention, the first polymerization step may or may not include an emulsifier. In other words, the emulsifier may be included in both the first and second polymerization steps, may be included only in the first polymerization step and not in the second polymerization step, or may not be included in the first polymerization step and only in the second polymerization step.

[0098] According to one embodiment of the present invention, the emulsifier being introduced in the first polymerization step includes cases where it is introduced all at once in the first polymerization step and not introduced in the second polymerization step, or cases where some of it is introduced in the first polymerization step and the remainder is introduced in the second polymerization step.

[0099] According to one embodiment of the present invention, when an emulsifier is introduced in batches in the first polymerization step, the emulsifier may be at least one selected from the group consisting of sodium dicyclohexyl sulfosuccinate, sodium di-(cyclohexyl)-sulfosuccinate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium octadecyl sulfate, sodium oleic sulfate, potassium dodecyl sulfate and potassium octadecyl sulfate, fatty acid potassium salts, and sodium rosinate.

[0100] According to one embodiment of the present invention, when an emulsifier is introduced in batches in the first polymerization step, the emulsifier may be introduced in batches in an amount of 0.1 to 0.6 parts by weight, preferably 0.2 to 0.4 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the polymerization stability of the graft polymerization can be improved.

[0101] According to one embodiment of the present invention, when an emulsifier is added in the first polymerization step, the fluidity index of the resin composition produced can be improved.

[0102] Meanwhile, according to one embodiment of the present invention, when an emulsifier is not added in the first polymerization step, an emulsifier is added in the second polymerization step, and in this case, the mechanical stability of the produced graft copolymer latex is secured, and the flame retardancy of the produced resin composition can be further improved.

[0103]

[0104] 2-2) Second polymerization stage

[0105] According to one embodiment of the present invention, the second polymerization step is performed after the first polymerization step by continuously adding an aromatic vinyl monomer and a vinyl cyan monomer to carry out a polymerization reaction.

[0106] According to one embodiment of the present invention, the second polymerization step can be performed at a temperature in the range of 65°C to 75°C.

[0107]

[0108] According to one embodiment of the present invention, the aromatic vinyl monomer continuously introduced in the second polymerization step may be at least one selected from the group consisting of styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p-methylphenyl)styrene, and 1-vinyl-5-hexylnaphthalene, and a specific example thereof may be styrene.

[0109] According to one embodiment of the present invention, the content of the aromatic vinyl monomer continuously added in the second polymerization step may be 20 to 25 parts by weight, preferably 21 to 23 parts by weight, based on 100 parts by weight of the sum of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the processability of the graft copolymer can be improved.

[0110]

[0111] According to one embodiment of the present invention, the vinyl cyan monomer continuously introduced in the second polymerization step may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile, and a specific example thereof may be acrylonitrile.

[0112] According to one embodiment of the present invention, the vinyl cyan monomer continuously added in the second polymerization step may be 5 to 10 parts by weight, preferably 6 to 8 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the chemical resistance of the graft copolymer can be improved.

[0113]

[0114] According to one embodiment of the present invention, a molecular weight regulator may be continuously added in the second polymerization step.

[0115] According to one embodiment of the present invention, the molecular weight regulator may be at least one selected from the group consisting of t-dodecyl mercaptan, n-dodecyl mercaptan, and α-methyl styrene dimer, and among these, t-dodecyl mercaptan is preferred.

[0116] According to one embodiment of the present invention, the molecular weight regulator may be added in an amount of 0.05 to 0.5 parts by weight, preferably 0.10 to 0.3 parts by weight, based on 100 parts by weight of the total of the diene rubber polymer, vinyl cyanide monomer, and vinyl aromatic monomer. When the above-described range is satisfied, the weight average molecular weight of the shell grafted onto the conjugated diene polymer core can be easily controlled.

[0117]

[0118] According to one embodiment of the present invention, the initiator can be continuously added in the second polymerization step.

[0119] According to one embodiment of the present invention, the initiator may be at least one selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, hydroperoxide, t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide, 3,5,5-trimethylhexanol peroxide, t-butyl peroxy isobutyrate, azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile and azobisisobutyric acid (butyric acid) methyl, and among these Hydroperoxide is preferred.

[0120] According to one embodiment of the present invention, in the second polymerization step, the initiator may be continuously added in an amount of 0.01 to 0.5 parts by weight, preferably 0.05 to 0.3 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the polymerization stability of the graft polymerization can be improved, while the residual amount of the initiator in the graft copolymer can be minimized.

[0121]

[0122] According to one embodiment of the present invention, the second polymerization step may or may not include an emulsifier. In other words, the emulsifier may be included in both the first and second polymerization steps, may be included only in the first polymerization step and not in the second polymerization step, or may not be included in the first polymerization step and only in the second polymerization step.

[0123] According to one embodiment of the present invention, the introduction of the emulsifier in the second polymerization step includes a case where a part of the emulsifier is introduced in the first polymerization step and the remainder of the emulsifier is continuously introduced in the second polymerization step, or a case where the emulsifier is not introduced in the first polymerization step and the emulsifier is continuously introduced in the second polymerization step.

[0124] According to one embodiment of the present invention, when an emulsifier is continuously added in the second polymerization step, the emulsifier may be at least one selected from the group consisting of sodium dicyclohexyl sulfosuccinate, sodium di-(cyclohexyl)-sulfosuccinate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium octadecyl sulfate, sodium oleic sulfate, potassium dodecyl sulfate and potassium octadecyl sulfate, fatty acid potassium salts, and sodium rosinate.

[0125] According to one embodiment of the present invention, when an emulsifier is continuously added in the second polymerization step, the emulsifier may be added in an amount of 0.3 to 0.7 parts by weight, preferably 0.4 to 0.6 parts by weight, based on 100 parts by weight of the total of the conjugated diene polymer latex (based on solid content), the aromatic vinyl monomer, and the vinyl cyan monomer. When the above-described range is satisfied, the mechanical stability of the produced graft copolymer latex is secured, and the flame retardancy of the produced resin composition can be further improved.

[0126] Meanwhile, according to one embodiment of the present invention, when the emulsifier is not added in the second polymerization step, the emulsifier is added in batches in the first polymerization step, and in this case, the polymerization stability of the graft polymerization can be improved.

[0127]

[0128] According to one embodiment of the present invention, at the end of the second polymerization step, a reaction catalyst may be further added. The reaction catalyst may be at least one selected from the group consisting of sodium pyrrolate, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, dextrose, tetrasodium pyrophosphate, and sodium sulfate, and among these, at least one selected from the group consisting of dextrose, ferrous sulfate, and sodium pyrophosphate is preferred.

[0129] According to one embodiment of the present invention, in the second polymerization step, the reaction catalyst may be added in an amount of 0.0001 to 0.1 parts by weight, preferably 0.0002 to 0.05 parts by weight, based on 100 parts by weight of the conjugated diene polymer latex (based on solid content), aromatic vinyl monomer, and vinyl cyan monomer. When the above-described range is satisfied, the polymerization stability of graft polymerization can be improved, while the residual amount of the reaction catalyst in the graft copolymer can be minimized.

[0130]

[0131] According to one embodiment of the present invention, a coagulant and an antioxidant are added to a graft copolymer latex obtained through a first polymerization step and a second polymerization step to coagulate the graft copolymer, and then a powder-type graft copolymer can be obtained through a dehydration and drying process.

[0132]

[0133] Resin composition

[0134] According to one embodiment of the present invention, the resin composition comprises a graft copolymer obtained according to one embodiment of the present invention.

[0135]

[0136] According to one embodiment of the present invention, the resin composition may include a non-graft copolymer including an aromatic vinyl monomer unit and a vinyl cyan monomer unit.

[0137] According to one embodiment of the present invention, the aromatic vinyl monomer for forming the aromatic vinyl monomer unit of the non-graft copolymer may be at least one selected from the group consisting of styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p-methylphenyl)styrene, and 1-vinyl-5-hexylnaphthalene, and a specific example thereof may be styrene.

[0138] According to one embodiment of the present invention, the vinyl cyan monomer for forming the vinyl cyan monomer unit of the non-graft copolymer may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile, and a specific example thereof may be acrylonitrile.

[0139] The non-graft copolymer may contain aromatic vinyl monomer units in an amount of 60 mass% or more and 80 mass% or less, and vinyl cyan monomer units in an amount of 20 mass% or more and 40 mass% or less. Specifically, the non-graft copolymer may contain aromatic vinyl monomer units in an amount of 62 mass% or more, 64 mass% or more, or 65 mass% or more, and may contain 78 mass% or less, 76 mass% or less, or 75 mass% or less. In addition, the non-graft copolymer may contain vinyl cyan monomer units in an amount of 22 mass% or more, 24 mass% or more, or 25 mass% or more, and may contain 38 mass% or less, 36 mass% or less, or 35 mass% or less. When the above-described conditions are satisfied, a resin composition having excellent processability and chemical resistance can be produced.

[0140]

[0141] According to one embodiment of the present invention, the resin composition may contain 20 parts by weight or more and 40 parts by weight or less of the graft copolymer and 60 parts by weight or more and 80 parts by weight or less of the non-graft copolymer, based on 100 parts by weight of the total of the graft copolymer and the non-graft copolymer. Specifically, the resin composition may contain 22 parts by weight or more, 25 parts by weight or more, or 27 parts by weight or more of the graft copolymer, and 38 parts by weight or less, 35 parts by weight or less, or 32 parts by weight or less of the graft copolymer, based on 100 parts by weight of the total of the graft copolymer and the non-graft copolymer. In addition, the resin composition may contain the non-graft copolymer in an amount of 62 parts by weight or more, 65 parts by weight or more, or 67 parts by weight or more, and 78 parts by weight or less, 75 parts by weight or less, or 72 parts by weight or less, based on 100 parts by weight of the total of the graft copolymer and the non-graft copolymer. When the above-described range is satisfied, a resin composition having excellent processability and impact resistance can be manufactured.

[0142]

[0143] According to one embodiment of the present invention, the resin composition may further include a flame retardant to ensure flame retardancy.

[0144] According to one embodiment of the present invention, the flame retardant is for imparting flame retardancy to the resin composition, and may be a halogen-based flame retardant, specifically, at least one of a chloro-based flame retardant and a brominated flame retardant, and more specifically, may be a brominated flame retardant.

[0145] According to one embodiment of the present invention, the brominated flame retardant may be at least one selected from the group consisting of tetrabromobisphenol A, decabromodiphenyloxide, decabrominateddiphenylethane, 1,2-bis(2,4,6-tribromophenyl)ethane, octabromo-1,2,2-trimethyl-1-phenylindane, tetrabromobisphenol A-bis(2,3-dibromopropyl ether), and 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, and a more specific example may be 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine.

[0146] According to one embodiment of the present invention, the flame retardant may be included in an amount of 10 parts by weight or more and 30 parts by weight or less, or 12 parts by weight or more and 28 parts by weight or less, based on 100 parts by weight of the graft copolymer and the non-graft copolymer, and more specifically, may be included in an amount of 15 parts by weight or more and 25 parts by weight or less. When the above-described range is satisfied, excellent flame retardancy and fluidity can be imparted to the flame retardant resin composition without deterioration of other physical properties.

[0147]

[0148] According to one embodiment of the present invention, the flame-retardant resin composition may further include a flame-retardant adjuvant. The flame-retardant adjuvant used in the present invention may be at least one selected from the group consisting of antimony trioxide, polysiloxane compounds, biotite, muscovite, iron oxide, tungsten oxide, and calcium carbonate, and a more specific example may be antimony trioxide.

[0149] The above flame retardant auxiliary agent may be included in an amount of 1 part by weight or more and 7 parts by weight or less based on 100 parts by weight of the graft copolymer and the non-graft copolymer. More specifically, the above flame retardant auxiliary agent may be included in an amount of 2 parts by weight or more and 5 parts by weight or less based on 100 parts by weight of the graft copolymer and the non-graft copolymer. When the above-described range is satisfied, excellent flame retardancy can be imparted to the flame retardant resin composition without deterioration of other physical properties.

[0150]

[0151] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0152]

[0153] Example 1

[0154] <Manufacture of conjugated diene polymer latex>

[0155] In a nitrogen-exchanged reactor, 70 parts by weight of ion-exchanged water, 70 parts by weight of 1,3-butadiene as a monomer, 0.8 parts by weight of fatty acid soap and 1.0 parts by weight of potassium rosin salt as emulsifiers, 1.2 parts by weight of potassium carbonate (K2CO3) as an electrolyte, 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator, and 0.3 parts by weight of potassium organic persulfate as a polymerization initiator were charged in batches, and then the polymerization reaction was started at a reaction temperature of 74°C. When the polymerization conversion was 30% to 40%, the remaining 30 parts by weight of 1,3-butadiene was continuously charged for 5 hours, and when the polymerization conversion was 60%, 0.15 parts by weight of potassium persulfate and 0.1 parts by weight of tertiary dodecyl mercaptan were charged in batches, and then the temperature was raised to 80°C to initiate the polymerization reaction. Thereafter, when the polymerization conversion rate was 75%, 0.03 parts by weight of t-butyl hydroperoxide, 0.054 parts by weight of dextrose, 0.04 parts by weight of sodium pyrrolate, and 0.002 parts by weight of ferrous sulfate were added, and when the polymerization conversion rate was 90%, the reaction was terminated to obtain a conjugated diene polymer latex having a gel content of 76%, an average particle size of 300 nm, and a content of particles having a particle size of 150 nm or less in the particle size distribution of 0%. The total time required for the polymerization reaction at this time was 25 hours.

[0156]

[0157] <Manufacturing of graft copolymer latex>

[0158] A mixed solution containing 60 parts by weight (based on solid content) of the manufactured conjugated diene polymer latex, 100 parts by weight of ion-exchanged water, 7.5 parts by weight of styrene as monomers, 2.5 parts by weight of acrylonitrile, 0.05 parts by weight of hydroperoxide as an initiator, 0.08 parts by weight of dextrose as a reaction catalyst, 0.05 parts by weight of sodium pyrophosphate, and 0.001 parts by weight of ferrous sulfate was charged all at once into a nitrogen-filled polymerization reactor, and the reaction was initiated at 50°C (first polymerization stage).

[0159] After the first polymerization step, 22.5 parts by weight of styrene as a monomer, 7.5 parts by weight of acrylonitrile, 0.6 parts by weight of a potassium salt of a fatty acid as an emulsifier, 0.12 parts by weight of t-dodecyl mercaptan as a molecular weight regulator, and 0.1 parts by weight of hydroperoxide as an initiator were continuously added in an emulsified state (emulsified monomer) while the temperature was raised to 70°C for about an hour (second polymerization step).

[0160] At the end of the second polymerization step, 0.04 parts by weight of dextrose, 0.03 parts by weight of sodium pyrrolate, and 0.0005 parts by weight of ferrous sulfate were added at once, and the temperature was raised to 80°C over 1 hour to complete the reaction, thereby obtaining a graft copolymer latex in which graft copolymer particles (solid content) were dispersed (third polymerization step).

[0161]

[0162] <Manufacture of graft copolymer powder>

[0163] 0.4 parts by weight of antioxidant (A / O) was added to the graft copolymer latex after the reaction was completed, and after coagulation with 1.7 parts by weight of sulfuric acid and dehydration, the graft copolymer powder with less than 1% moisture was obtained after drying in a hot air fluidized bed dryer.

[0164]

[0165] <Manufacture of resin composition>

[0166] 30 parts by weight of the obtained graft copolymer powder, 70 parts by weight of styrene-acrylonitrile (SAN, 81HF from LG Chemical Co., Ltd.) pellets, 18 parts by weight of a flame retardant (2,4,6-tris(2,4,6-bromophenoxy)-1,3,5-triazine, trade name FR-245), 3 parts by weight of a flame retardant auxiliary agent (antimony trioxide), 3.0 parts by weight of a lubricant (ethylene bis stearamide), 0.2 parts by weight of a stabilizer (Irganox 1076), and 0.1 parts by weight of an anti-drip agent (polytetrafluoroethylene) were uniformly mixed with a Henschel mixer and extruded and injected to prepare a resin composition.

[0167]

[0168] Example 2

[0169] <Manufacture of conjugated diene polymer latex>

[0170] In a nitrogen-exchanged reactor, 70 parts by weight of ion-exchanged water, 70 parts by weight of 1,3-butadiene as a monomer, 0.8 parts by weight of fatty acid soap and 1.0 parts by weight of potassium rosin salt as emulsifiers, 1.2 parts by weight of potassium carbonate (K2CO3) as an electrolyte, 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator, and 0.3 parts by weight of potassium organic persulfate as a polymerization initiator were charged in batches, and then the polymerization reaction was started at a reaction temperature of 74°C. When the polymerization conversion was 30% to 40%, 20 parts by weight of 1,3-butadiene was continuously charged for 5 hours, and when the polymerization conversion was 60%, 0.15 parts by weight of potassium persulfate and 0.1 parts by weight of tertiary dodecyl mercaptan were charged in batches, and then the temperature was raised to 80°C to initiate the polymerization reaction. Thereafter, when the polymerization conversion rate was 75%, the remaining 10 parts by weight of 1,3-butadiene, 0.03 parts by weight of t-butyl hydroperoxide, 0.054 parts by weight of dextrose, 0.04 parts by weight of sodium pyrrolate, and 0.002 parts by weight of ferrous sulfate were added, and when the polymerization conversion rate was 90%, the reaction was terminated to obtain a conjugated diene polymer latex having a gel content of 73%, an average particle size of 300 nm, and a content of particles having a particle size of 150 nm or less of 5% among the particle size distribution. The total time required for the polymerization reaction at this time was 25 hours.

[0171]

[0172] A resin composition was prepared in the same manner as in Example 1, except that the obtained conjugated diene polymer latex was used in the first polymerization step.

[0173]

[0174] Example 3

[0175] <Manufacture of conjugated diene polymer latex>

[0176] In a nitrogen-substituted reactor, 70 parts by weight of ion-exchanged water, 65 parts by weight of 1,3-butadiene as a monomer, 0.8 parts by weight of fatty acid soap and 1.0 parts by weight of potassium rosin salt as emulsifiers, 1.2 parts by weight of potassium carbonate (K2CO3) as an electrolyte, 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator, and 0.3 parts by weight of potassium organic persulfate as a polymerization initiator were charged in batches, and then the polymerization reaction was started at a reaction temperature of 74°C. When the polymerization conversion was 30% to 40%, 20 parts by weight of 1,3-butadiene was continuously charged for 5 hours, and when the polymerization conversion was 60%, 0.15 parts by weight of potassium persulfate and 0.1 parts by weight of tertiary dodecyl mercaptan were charged in batches, and then the temperature was raised to 80°C to initiate the polymerization reaction. Afterwards, when the polymerization conversion rate was 75%, the remaining 15 parts by weight of 1,3-butadiene, 0.03 parts by weight of t-butyl hydroperoxide, 0.054 parts by weight of dextrose, 0.04 parts by weight of sodium pyrrolate, and 0.002 parts by weight of ferrous sulfate were added, and when the polymerization conversion rate was 90%, the reaction was terminated to obtain a conjugated diene polymer latex having a gel content of 71%, an average particle size of 297 nm, and a content of particles having a particle size of 150 nm or less in the particle size distribution of 12%. The total time required for the polymerization reaction at this time was 25 hours.

[0177]

[0178] A resin composition was prepared in the same manner as in Example 1, except that the obtained conjugated diene polymer latex was used in the first polymerization step.

[0179]

[0180] Example 4

[0181] A resin composition was prepared in the same manner as in Example 1, except that the conjugated diene polymer latex obtained in Example 2 was used in the first polymerization step, 0.6 parts by weight of a fatty acid potassium salt was added as an emulsifier in the first polymerization step, and no emulsifier was added in the second polymerization step.

[0182]

[0183] Example 5

[0184] A resin composition was prepared in the same manner as in Example 1, except that the conjugated diene polymer latex obtained in Example 2 was used in the first polymerization step, 0.3 parts by weight of a fatty acid potassium salt was added as an emulsifier in the first polymerization step, and 0.3 parts by weight of a fatty acid potassium salt was added as an emulsifier in the second polymerization step.

[0185]

[0186] Example 6

[0187] A resin composition was prepared in the same manner as in Example 1, except that the conjugated diene polymer latex obtained in Example 2 was used in the first polymerization step, 0.4 parts by weight of a fatty acid potassium salt was added as an emulsifier in the first polymerization step, and 0.4 parts by weight of a fatty acid potassium salt was added as an emulsifier in the second polymerization step.

[0188]

[0189] Example 7

[0190] A resin composition was prepared in the same manner as in Example 1, except that the conjugated diene polymer latex obtained in Example 2 was used in the first polymerization step and 0.8 parts by weight of a fatty acid potassium salt was added as an emulsifier in the second polymerization step.

[0191]

[0192] Comparative Example 1

[0193] <Manufacture of conjugated diene polymer latex>

[0194] In a nitrogen-substituted reactor, 70 parts by weight of ion-exchanged water, 65 parts by weight of 1,3-butadiene as a monomer, 0.8 parts by weight of fatty acid soap and 1.0 parts by weight of potassium rosin salt as emulsifiers, 1.2 parts by weight of potassium carbonate (K2CO3) as an electrolyte, 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator, and 0.3 parts by weight of potassium organic persulfate as a polymerization initiator were charged in batches, and then the polymerization reaction was started at a reaction temperature of 74°C. When the polymerization conversion was 30% to 40%, 18 parts by weight of 1,3-butadiene was continuously charged for 5 hours, and when the polymerization conversion was 60%, 0.15 parts by weight of potassium persulfate and 0.1 parts by weight of tertiary dodecyl mercaptan were charged in batches, and then the temperature was raised to 80°C to initiate the polymerization reaction. Afterwards, when the polymerization conversion rate was 75%, the remaining 12 parts by weight of 1,3-butadiene, 0.03 parts by weight of t-butyl hydroperoxide, 0.054 parts by weight of dextrose, 0.04 parts by weight of sodium pyrrolate, and 0.002 parts by weight of ferrous sulfate were added, and when the polymerization conversion rate was 90%, the reaction was terminated to obtain a conjugated diene polymer latex having a gel content of 70%, an average particle size of 294 nm, and a content of particles having a particle size of 150 nm or less in the particle size distribution of 14%.

[0195]

[0196] A resin composition was prepared in the same manner as in Example 1, except that the obtained conjugated diene polymer latex was used in the first polymerization step.

[0197]

[0198] Comparative Example 2

[0199] <Manufacture of conjugated diene polymer latex>

[0200] In a nitrogen-exchanged reactor, 130 parts by weight of ion-exchanged water, 80 parts by weight of 1,3-butadiene as a monomer, 2.5 parts by weight of fatty acid soap as an emulsifier, 0.3 parts by weight of potassium carbonate (K2CO3) as an electrolyte, 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator, 0.03 parts by weight of t-butyl hydroperoxide as a polymerization initiator, 0.054 parts by weight of dextrose, 0.04 parts by weight of sodium pyrophosphate, and 0.002 parts by weight of ferrous sulfate were all charged together, and a polymerization reaction was started at a reaction temperature of 60°C. Thereafter, when the polymerization conversion rate was 40%, 20 parts by weight of the remaining 1,3-butadiene was continuously added for 5 hours, and when the polymerization conversion rate was 60%, 0.15 parts by weight of potassium persulfate and 0.1 parts by weight of tertiary dodecyl mercaptan were added all at once, and the temperature was raised to 80℃ to initiate a polymerization reaction. Then, when the polymerization conversion rate was 95%, the reaction was terminated, and a conjugated diene polymer latex having a gel content of 92%, an average particle size of 330 nm, and a content of particle size distribution having a particle size of 150 nm or less of 5% was obtained.

[0201]

[0202] A resin composition was prepared in the same manner as in Example 1, except that the obtained conjugated diene polymer latex was used in the first polymerization step.

[0203]

[0204] Comparative Example 3

[0205] <Manufacture of conjugated diene polymer latex>

[0206] In a nitrogen-exchanged reactor, 70 parts by weight of ion-exchanged water, 70 parts by weight of 1,3-butadiene as a monomer, 0.8 parts by weight of fatty acid soap and 1.0 parts by weight of potassium rosin salt as emulsifiers, 1.0 parts by weight of potassium carbonate (K2CO3) as an electrolyte, 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator, and 0.3 parts by weight of potassium organic persulfate as a polymerization initiator were charged in batches, and then the polymerization reaction was started at a reaction temperature of 74°C. When the polymerization conversion was 30% to 40%, 25 parts by weight of 1,3-butadiene was continuously charged for 5 hours, and when the polymerization conversion was 60%, 0.15 parts by weight of potassium persulfate and 0.1 parts by weight of tertiary dodecyl mercaptan were charged in batches, and then the temperature was raised to 80°C to initiate the polymerization reaction. Afterwards, when the polymerization conversion rate was 75%, the remaining 5 parts by weight of 1,3-butadiene, 0.03 parts by weight of t-butyl hydroperoxide, 0.054 parts by weight of dextrose, 0.04 parts by weight of sodium pyrrolate, and 0.002 parts by weight of ferrous sulfate were added, and when the polymerization conversion rate was 95%, the reaction was terminated to obtain a conjugated diene polymer latex having a gel content of 65%, an average particle size of 280 nm, and a content of particles having a particle size of 150 nm or less of 5% in the particle size distribution.

[0207]

[0208] A resin composition was prepared in the same manner as in Example 1, except that the obtained conjugated diene polymer latex was used in the first polymerization step.

[0209]

[0210] Comparative Example 4

[0211] <Manufacture of conjugated diene polymer latex (A)>

[0212] 100 parts by weight of butadiene, 2.5 parts by weight of emulsifier (potassium rosinate), 0.5 parts by weight of initiator (potassium persulfate), 0.4 parts by weight of chain transfer agent (t-dodecyl mercaptan), 1.5 parts by weight of buffer (potassium carbonate), and 100 parts by weight of deionized water were placed in an autoclave, and a polymerization reaction was performed at a reaction temperature of 50°C in a nitrogen atmosphere, thereby obtaining a conjugated diene polymer latex (A) having a gel content of 75%, an average particle diameter of 298 nm, and a content of particles having a particle diameter of 150 nm or less of 6% in the particle size distribution.

[0213]

[0214] <Manufacture of conjugated diene polymer latex (B)>

[0215] In an autoclave, 75 parts by weight of butadiene, 25 parts by weight of styrene, 3.0 parts by weight of an emulsifier (potassium rosinate), 0.5 parts by weight of an initiator (ammonium persulfate), 0.3 parts by weight of a chain transfer agent (t-dodecyl mercaptan), 1.5 parts by weight of a buffer (sodium phosphate dibasic), and 70 parts by weight of deionized water were added, and a polymerization reaction was performed at a reaction temperature of 55°C in a nitrogen atmosphere, thereby obtaining a conjugated diene polymer latex (B) having a gel content of 15%, an average particle size of 273 nm, and a content of particles having a particle size of 150 nm or less in the particle size distribution of 10%.

[0216]

[0217] <Preparation of conjugated diene polymer latex composition>

[0218] The obtained conjugated diene polymer latex (A) and conjugated diene polymer latex (B) were mixed at a ratio of 85:15 to prepare a conjugated diene polymer latex composition.

[0219]

[0220] A resin composition was prepared in the same manner as in Example 1, except that the obtained conjugated diene polymer latex composition was used in the first polymerization step.

[0221]

[0222] Experimental Example 1

[0223] The physical properties of each graft copolymer latex obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were measured as follows, and the measured values ​​are recorded in Tables 1 to 3.

[0224]

[0225] * Grafting ratio (%): 0.4 parts by weight of an antioxidant (A / O) was added to each of the graft copolymer latexes obtained in Examples 1 to 7 and Comparative Examples 1 to 4, coagulated with 1.7 parts by weight of sulfuric acid, dehydrated, and dried in a hot air fluidized bed dryer to obtain a graft copolymer powder having a moisture content of less than 1%, and 1 g of the obtained graft copolymer powder was added to 50 ml of acetone and stirred for 24 hours, and then the solution was separated into sol-gel using a centrifuge, and the separated acetone solution was dropped into methanol to obtain a non-grafted portion, which was dried at 60 to 120°C and weighed, and then the weight of the grafted monomer was calculated by deducting the weight of the non-grafted portion and the weight of the conjugated diene polymer from 1 g of the obtained graft copolymer powder, and then the grafting ratio was calculated according to the following mathematical formula 1. Here, the weight of the conjugated diene polymer refers to the solid weight of the conjugated diene polymer theoretically added to 1 g of graft copolymer powder; or the weight of the conjugated diene polymer measured by analyzing the graft copolymer using infrared spectroscopy.

[0226]

[0227] [Mathematical Formula 1]

[0228] Grafting ratio = {Weight of grafted monomer (g) / Weight of conjugated diene polymer (g)} × 100

[0229]

[0230] * Coagulation amount (weight %): Each of the graft copolymer latexes obtained in Examples 1 to 7 and Comparative Examples 1 to 4 was filtered through a 100-mesh mesh made of SUS304, placed in a convention oven, and left at 80°C for 720 minutes. Thereafter, the weight of the coagulants caught in the 100-mesh mesh was measured, and the coagulation amount of the graft copolymer latex was calculated according to the following mathematical equation 2.

[0231]

[0232] [Equation 2]

[0233] Amount of coagulation = {(Weight of coagulation caught in a 100-mesh screen) / Theoretical total weight of butadiene rubber polymer, styrene, acrylonitrile, and additives used in the production of graft copolymer} × 100

[0234]

[0235] * Mechanical Stability (min): The time until the latex stability is destroyed and coagulation occurs was measured for 300 to 400 g of each of the graft copolymer latexes obtained in Examples 1 to 7 and Comparative Examples 1 to 4 using a Robomix device from PRIMIX under a shear condition of 12,000 rpm. The higher the mechanical stability, the greater the resistance to stress that may occur during transportation of the polymerized latex.

[0236]

[0237] Experimental Example 2

[0238] For each of the resin compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 4, the physical properties were measured using the following methods, and the measured values ​​are recorded in Tables 1 to 3.

[0239]

[0240] * Izod impact strength (kg·cm / cm, 1 / 4``): Measured according to ASTM D256.

[0241]

[0242] * Flow index (g / 10 min): Measured under the conditions of 220℃ and 10kg according to ASTM D1238.

[0243]

[0244] * Tensile strength (kg / cm) 2 ): According to ASTM D638, a UTM (manufacturer; Instron, model number 4466) was used to pull a specimen with a thickness of 3.2 mm at a cross head speed of 5 mm / min, and the point where the specimen was cut was measured.

[0245]

[0246] * Flame retardancy (sec): The resin composition manufactured above was made into a specimen with a thickness of 2.0 mm, a width of 12.7 mm, and a length of 127 mm, and the time until the flame goes out after combustion under the conditions specified in the UL-94 vertical combustion evaluation method was measured twice a total of five times, and the average value was calculated.

[0247]

[0248] Example 1 Example 2 Example 3 Example 4 Conjugated diene polymer latex Gel content (%) 76737173 Average particle size (based on solid content, nm) 300300297300 Small particle size ratio (%) 05125 Emulsifier usage (weight parts) 1st polymerization stage 0000.6 2nd polymerization stage 0.60.60.60 Graft copolymer latex Average particle size (based on solid content, nm) 343338327328 Coagulation (weight%) 0.030.040.070.12 Mechanical stability (min) 26242212 Graft ratio (based on solid content, %) 40.441.843.542.8 Molecular weight (based on solid content, g / mol) 88,40090,80093,40092,400 Resin composition Izod Impact strength (kg cm / cm, 1 / 4``) 22.42 2.02 1.8 20.7 Flow index (g / 10 min) 53.15 2.45 1.65 1.8 Tensile strength (kg / cm 2 )423424424423 Flame retardancy (sec)2.42.83.24.4

[0249] Example 5 Example 6 Example 7 Conjugated diene polymer latex Gel content (%) 7 37 37 3 Average particle size (based on solid content, nm) 300 300 300 Small particle size ratio (%) 5 5 Emulsifier usage (weight parts) 1st polymerization stage 0.3 0.4 2nd polymerization stage 0.3 0.4 0.8 Graft copolymer latex Average particle size (based on solid content, nm) 3 30 32 5 33 1 Coagulation (weight%) 0.1 0 0.0 8 0.0 4 Mechanical stability (min) 1 8 2 5 3 4 Graft ratio (based on solid content, %) 4 2.4 4 0.5 3 9.1 Molecular weight (based on solid content, g / mol) 9 1,50 0 8 7,50 0 8 6,100 Izod impact strength of resin composition (kg cm / cm, 1 / 4``)21.120.419.2Flow index (g / 10 min)52.153.554.3Tensile strength (kg / cm) 2 )422423423Flammability(sec)4.04.24.0

[0250] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Conjugated diene polymer latex (composition) Gel content (%) 70926575 / 15 Average particle size (based on solid content, nm) 294330280298 / 273 Small particle size ratio (%) 14556 / 10 Emulsifier usage (parts by weight) 1st polymerization stage 0000 2nd polymerization stage 0.6 0.6 0.6 0.6 Graft copolymer latex Average particle size (based on solid content, nm) 300 348 321 285 Coagulation (% by weight) 0.18 0.03 0.08 0.42 Mechanical stability (min) 15282216 Grafting ratio (based on solid content, %) 45.4 26.5 42.7 48.1 Molecular weight (based on solid content, g / mol)96,00078,40087,80088,000Izod impact strength of resin composition(kg·cm / cm, 1 / 4``)18.520.219.818.5Flow index(g / 10 min)50.556.851.155.6Tensile strength(kg / cm 2 )411402408384 Flame retardancy (sec)6.08.07.56.2

[0251] As shown in Tables 1 to 3 above, it can be confirmed that the resin compositions of Examples 1 to 7 prepared using the conjugated diene polymer latex according to the present invention, which includes conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt% and a proportion of particles having a size of 150 nm or less in a particle distribution of 10% or less, have improved impact strength, flow index, tensile strength, and flame retardancy compared to the resin composition of Comparative Example 1 prepared using the conjugated diene polymer latex including conjugated diene polymer particles having a proportion of particles having a size of 150 nm or less in a particle distribution of more than 10%.

[0252] It was confirmed that the resin compositions of Examples 1 to 7 had improved tensile strength and flame retardancy compared to the resin composition of Comparative Example 2, which was manufactured using a conjugated diene polymer latex including conjugated diene polymer particles having a gel content of 80 wt% or more.

[0253] It was confirmed that the resin compositions of Examples 1 to 7 had improved tensile strength and flame retardancy compared to the resin composition of Comparative Example 3, which was prepared using a conjugated diene polymer latex including conjugated diene polymer particles having a gel content of less than 70 wt%.

[0254] It was confirmed that the resin compositions of Examples 1 to 7 had improved tensile strength and flame retardancy compared to the resin composition of Comparative Example 4, which was prepared using a conjugated diene polymer latex composition comprising different types of conjugated diene polymer particles having different gel contents and average particle diameters.

[0255] It was confirmed that the resin compositions of Examples 1 to 3, in which an emulsifier was not added in the first polymerization step and an appropriate amount of an emulsifier was added in the second polymerization step, had improved flame retardancy compared to the resin composition of Example 3, in which an emulsifier was added only in the first polymerization step, and the resin compositions of Examples 4 and 5, in which an emulsifier was added in both the first and second polymerization steps.

[0256] It was confirmed that the resin compositions of Examples 1 to 3, in which no emulsifier was added in the first polymerization step and an appropriate amount of emulsifier was added in the second polymerization step, had improved impact strength and flame retardancy compared to the resin composition of Example 7, in which no emulsifier was added in the first polymerization step and an emulsifier was added in the second polymerization step but in an excessive amount.

Claims

1. A step (S1) of obtaining a conjugated diene polymer latex including conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt% and a proportion of particles having a particle size of 150 nm or less of 10% or less among the particle distribution; and A method for producing a graft copolymer, comprising a step (S2) of introducing an aromatic vinyl monomer and a vinyl cyan monomer in the presence of the above conjugated diene polymer latex and performing graft polymerization to obtain a graft copolymer latex.

2. In paragraph 1, A method for producing a graft copolymer, wherein the average particle diameter of the conjugated diene polymer particles is 280 nm or more and 320 nm or less.

3. In paragraph 1, The above S2 step: A first polymerization step (S2-1) in which the above conjugated diene polymer latex, an aromatic vinyl monomer, a vinyl cyan monomer and a polymerization initiator are introduced in batches; and A method for producing a graft copolymer, comprising a second polymerization step (S2-2) of continuously adding an aromatic vinyl monomer, a vinyl cyan monomer, and an emulsifier after the first polymerization step (S2-1).

4. In paragraph 3, A method for producing a graft copolymer, wherein no emulsifier is added in the first polymerization step (S2-1).

5. In paragraph 3, For 100 parts by weight of the conjugated diene polymer latex, aromatic vinyl monomer and vinyl cyan monomer introduced in the first polymerization step and the aromatic vinyl monomer and vinyl cyan monomer introduced in the second polymerization step, A method for producing a graft copolymer, wherein the emulsifier introduced in the second polymerization step (S2-2) is introduced in an amount of 0.4 parts by weight or more and 0.7 parts by weight or less.

6. In paragraph 1, The average particle diameter of the above conjugated diene polymer particles is smaller than the average particle diameter of the above graft copolymer, A method for producing a graft copolymer, wherein the average particle diameter of the graft copolymer is 300 nm or more and 350 nm or less.

7. In paragraph 6, A method for producing a graft copolymer, wherein the average particle diameter of the conjugated diene polymer particles is smaller than the average particle diameter of the graft copolymer.

8. In paragraph 1, A method for producing a graft copolymer, wherein the conjugated diene polymer particles have a gel content of 70 wt% or more and less than 80 wt%, and the proportion of particles having a particle size of 150 nm or less among the particles is 9% or less.

9. A conjugated diene polymer latex comprising conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt% and a proportion of particles having a particle size of 150 nm or less of 10% or less among the particles.

10. A conjugated diene polymer latex comprising conjugated diene polymer particles having a gel content of 70 wt% or more and less than 80 wt% and a proportion of particles having a particle size of 150 nm or less of 9 wt% or less.