WO2016043424A1 - Thermoplastic resin composition and thermoplastic resin molded article prepared therefrom - Google Patents

Abstract

The present invention provides a thermoplastic resin composition comprising, in a weight ratio of 35:65 to 70:30: a graft copolymer (A) in which (meth)acrylic ester, a vinyl cyanide compound and an aromatic vinyl compound are graft-polymerized to conjugated diene based rubber latex; and a copolymer (B) of a (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyanide based compound, wherein in the event of irradiating light in a wavelength range of 450 nm to 680 nm, the refractive index difference between the graft copolymer (A) and the copolymer (B) of a (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyanide based compound is less than 0.003, and when measuring the flow index according to ASTM D1238, the flow index is 4.0g/10 min or less. A thermoplastic resin molded article prepared from said thermoplastic resin composition exhibits high environmental stress cracking resistance (ESCR) as well as excellent impact resistance and transparency.

Description

Thermoplastic resin composition and thermoplastic resin molded article produced therefrom

Citation with Related Applications

This application claims the benefit of priority based on Korean Patent Application No. 2014-0122822 filed on September 16, 2014 and Korean Patent Application No. 2015-0104270 filed on July 23, 2015. The contents are included as part of this specification.

Technical Field

The present invention relates to a thermoplastic resin composition exhibiting high environmental stress crack resistance (ESCR) with excellent impact resistance and transparency, and a thermoplastic resin molded article prepared therefrom.

In general, excellent environmental stress cracking resistance (ESCR, chemical resistance) such as excellent impact resistance and transparency, alcohol resistance and oil resistance to materials used in the manufacture of medical products is required. As such medical materials, polyvinyl chloride (PVC) resins, polycarbonate (PC) resins, acrylonitrile-butadiene-styrene (ABS) resins, polymethyl methacrylate (PMMA) resins, polystyrene (PS) resins, Styrene-acrylonitrile (SAN) resin etc. are used.

Polyvinyl chloride-based (PVC) resin has excellent flame retardancy, transparency and chemical resistance, and is used for medical treatment such as needle hub, patient connector, and urine container. Mainly used for products. However, polyvinyl chloride-based resins have a human stability problem due to the migration of the plasticizer because the use of a plasticizer is necessarily accompanied.

In addition, polycarbonate resin has excellent transparency and impact resistance, but low environmental stress crack resistance (ESCR, chemical resistance), there is a problem that the crack occurs due to the effect of residual molding stress when the cleaning agent contacts.

In addition, acrylonitrile-butadiene-styrene (ABS) resin contains acrylonitrile compound, so it is excellent in environmental stress crack resistance (ESCR, chemical resistance), but it is opaque, so it is not applicable to medical products requiring transparency. There is.

In addition, polymethyl methacrylate (PMMA) resin, polystyrene (PS) resin and styrene-acrylonitrile (SAN) resin have excellent transparency, but have low environmental stress crack resistance (ESCR) to alcohol and impact strength. Not high enough In addition, polystyrene resins and styrene-acrylonitrile resins have a low impact strength, and therefore, there is a limit to application to medical products requiring high environmental stress crack resistance (chemical resistance), impact resistance and transparency.

Therefore, there is a need for the development of a resin having high environmental stress crack resistance (chemical resistance) with excellent impact resistance and transparency.

It is an object of the present invention to provide a thermoplastic resin composition having excellent impact resistance and transparency, low flow index and high environmental stress crack resistance (ESCR).

Another object of the present invention is to provide a thermoplastic resin molded article prepared from the thermoplastic resin composition.

In order to solve the above problems, according to an embodiment of the present invention, a graft copolymer (A) in which (meth) acrylic acid ester, vinyl cyan compound and aromatic vinyl compound are graft-polymerized on conjugated diene rubber latex; And a copolymer (B) of (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound in a weight ratio of 35:65 to 70:30, and when the light is irradiated in the wavelength range of 450 nm to 680 nm, A) and a copolymer (B) of the (meth) acrylic acid ester-vinyl cyan compound-aromatic vinyl compound have a refractive index difference of less than 0.003, and exhibit a flow index of 4.0 g / 10 min or less when the flow index is measured according to ASTM D1238. It provides a thermoplastic resin composition.

Further, according to another embodiment of the present invention, the graft copolymer (MABS) and methyl methacrylate-styrene-acryl grafted with methyl methacrylate, acrylonitrile and styrene with respect to conjugated diene rubber latex Ronitrile copolymer (MSAN) in a weight ratio of 35:65 to 70:30, and the conjugated diene-based rubber latex in an amount of 20% to 35% by weight based on the total weight of the composition, and in the 450nm to 680nm wavelength range Upon irradiation with light, the difference in refractive index between the graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer is less than 0.003, and the graft copolymer is methyl methacrylate and acryl with respect to conjugated diene rubber latex. Ronitrile and styrene are prepared by graft polymerization using a molecular weight modifier, wherein the methyl methacrylate, acrylonitrile and styrene are from 20: 2: 8 to It is used in a weight ratio of 40:10:15, wherein the molecular weight modifier is used in 0.05 to 0.4 parts by weight based on 100 parts by weight of the total of the conjugated diene rubber latex and the monomer grafted to the conjugated diene rubber latex It provides a thermoplastic resin composition.

Furthermore, according to another embodiment of the present invention, a thermoplastic resin molded article prepared from the thermoplastic resin composition is provided.

The thermoplastic resin composition according to the present invention may exhibit high environmental stress crack resistance (ESCR) by having a low flow index while having excellent impact resistance and transparency.

Therefore, the thermoplastic resin composition is useful as a material of a product, particularly a medical product, which requires excellent impact resistance and transparency and high environmental stress crack resistance (chemical resistance).

Hereinafter, the present invention will be described in more detail to aid in understanding the present invention.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

In order to impart transparency to the acrylonitrile-butadiene-styrene resin having low transparency, a method of introducing an acrylic acid alkyl ester or methacrylic acid alkyl ester compound has been implemented. However, the method has a low environmental stress crack resistance due to the (meth) acrylic acid alkyl ester introduced, there is a limit to the application of medical products. In order to introduce (meth) acrylic acid alkyl esters into acrylonitrile-butadiene-styrene resins to have properties that can be easily applied to medical products, the modulus in the final polymerized resin must be properly controlled and mixed for this purpose. The control of the ratio of each ingredient is an important factor.

Accordingly, in the present invention, a graft copolymer in which a (meth) acrylic acid ester, a vinyl cyan compound and an aromatic vinyl compound are graft-polymerized to a conjugated diene rubber latex having a similar refractive index, and a (meth) acrylic acid ester-aromatic vinyl compound -Thermoplastic resin composition which uses a copolymer of vinyl cyanide compound, but optimizes the content and mixing ratio of each component, which has excellent impact resistance and transparency, low flow index and high environmental stress crack resistance (ESCR) Can be provided.

Specifically, the thermoplastic resin composition according to an embodiment of the present invention is a graft copolymer (A) in which (meth) acrylic acid ester, vinyl cyan compound and aromatic vinyl compound are graft-polymerized on conjugated diene rubber latex; And a copolymer (B) of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound in a weight ratio of 35:65 to 70:30, wherein the graft copolymer (A) and the (meth) acrylic acid ester- The difference in refractive index of the copolymer (B) of the aromatic vinyl compound-vinyl cyan compound is less than 0.003 and shows a flow index (MI) of 4.0 g / 10 min or less when the flow index is measured according to ASTM D1238.

In the present invention, the term "refractive index" refers to the absolute index of refraction of a material (eg, monomer or polymer), which is recognized as the ratio of the rate of electromagnetic radiation in free space to the rate of radiation in the material. In this case, the radiation is visible light having a wavelength of 450 nm to 680 nm. The refractive index can be measured using a known method, generally using an Abbe Refractometer.

In addition, the refractive index of the graft copolymer may be calculated according to the following equation 1 using the refractive index and the content of each polymer of the graft copolymer configuration:

[Equation 1]

RI = ∑ (Wti × RIi)

In Formula 1, Wti is the weight fraction (%) of each component (or polymer) in the graft copolymer, and RIi is the refractive index of the graft copolymer-forming polymer.

Hereinafter, the present invention will be described in more detail.

A) Graft Copolymer

In the thermoplastic resin composition according to the embodiment of the present invention, the graft copolymer is a (meth) acrylic acid ester, a vinyl cyan compound and an aromatic vinyl compound graft polymerized on a conjugated diene rubber latex, specifically The core of the graft conjugated diene rubber latex; And a core-shell structure of a shell comprising a (meth) acrylic acid ester, an aromatic vinyl compound, and a vinyl cyan-based compound grafted onto the core.

As for the kind and content of the monomer compound which comprises the said graft copolymer, the refractive index difference with the copolymer (B) of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan type compound used for manufacture of a thermoplastic resin composition is 0.003 It may be appropriately determined under the conditions to be less than. Specifically, the graft copolymer is 45% to 75% by weight of the conjugated diene rubber latex core; And 25% by weight to 55% by weight of a shell including a (meth) acrylic acid ester, a vinyl cyan compound, and an aromatic vinyl compound on the core. In this case, the shell is 20 to 40 parts by weight, 2 to 10 parts by weight and 8 to 15 parts by weight of the (meth) acrylic acid ester, vinyl cyan compound, and aromatic vinyl compound, respectively, that is, 20: 2: 8 to 40:10 It may be included in a weight ratio of: 15. If the shell includes an acryl compound, a vinyl cyan compound and an aromatic vinyl compound in a weight ratio within the above range, especially when the vinyl cyan compound is included in the above ratio range, the flow index (MI) of the thermoplastic resin is As a result, the environmental stress crack resistance can be greatly improved.

In addition, in the graft copolymer, the conjugated diene rubber latex core may have an average particle diameter of 2000 GPa to 5000 GPa, a gel content of 70% to 95% by weight, and a swelling index of 12 to 30.

In the graft copolymer, the graft copolymer is similarly controlled by controlling the refractive index of the conjugated diene rubber latex core and a shell containing a (meth) acrylic acid ester, a vinyl cyan compound, and an aromatic vinyl compound described later. Can improve the transparency. Specifically, the difference in refractive index between the conjugated diene rubber latex core and the shell including the acrylic compound, the vinyl cyan compound, and the aromatic vinyl compound may be less than 0.003.

In the graft copolymer, the conjugated diene rubber latex may include a conjugated diene-based compound homopolymer or a copolymer of a conjugated diene-based compound and an ethylenically unsaturated compound. The compound may be one or more selected from the group consisting of 1,3-butadiene, 2-ethyl-1,3-butadiene, isoprene, chloroprene and 1,3-pentadiene. In addition, the ethylenically unsaturated compound may include an ethylenically unsaturated nitrile compound, an ethylenically unsaturated acid compound or a mixture thereof, such as acrylonitrile, methacrylonitrile, α-chloronitrile, styrene, alkyl styrene, vinyl naphthalene It may be one or more selected from the group consisting of chloroethyl vinyl ether, (meth) acrylamide, dibutyl maleate, dibutyl fumarate or diethyl maleate.

More specifically, the conjugated diene rubber latex may be one or more selected from the group consisting of butadiene homopolymer, isoprene homopolymer, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer and isobutylene-isoprene copolymer. have. Even more specifically, the conjugated diene rubber latex may be a butadiene homopolymer.

In the graft copolymer, (meth) acrylic acid ester is meant to include acrylic acid ester and methacrylic acid ester.

Specifically, the (meth) acrylic acid ester may be one or more selected from the group consisting of acrylic acid alkyl esters and methacrylic acid alkyl esters.

In addition, the acrylic acid alkyl ester may be specifically one or more selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate and 2-ethylhexyl acrylate, and more specifically, May be a metal acrylate.

In addition, the methacrylic acid alkyl ester is specifically one selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate and 2-ethylhexyl methacrylate It may be more than one, more specifically may be methyl methacrylate.

In the graft copolymer, the vinyl cyan compound may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, and derivatives thereof, and specifically, may be acrylonitrile.

In addition, in the graft copolymer, the aromatic vinyl compound is styrene, α-methylstyrene, vinyltoluene, alkyl styrene substituted with an alkyl group of C _1-3 (for example, o-methylstyrene, m-methylstyrene , p-methylstyrene, p-ethylstyrene, etc.) and styrene substituted with halogen may be one or more selected from the group consisting of, specifically, styrene.

In addition, the graft copolymer may have a weight average molecular weight (Mw) of 130,000 to 300,000 g / mol. When the graft copolymer has a weight average molecular weight in the above-described range, the flow index of the thermoplastic resin composition may be reduced, thereby exhibiting better environmental stress crack resistance. Typically, the weight average molecular weight of the polymer may be a polystyrene equivalent molecular weight, respectively, analyzed by gel permeation chromatography (GPC), but in the case of rubber, it is difficult to determine the exact weight average molecular weight. Accordingly, in the present invention, the weight average molecular weight of the graft copolymer can be calculated from the flow index of the copolymer, the rubber content and the content of the vinyl cyan compound-derived structural unit.

More specifically, the graft copolymer may be a methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS) graft copolymerized with methyl methacrylate, acrylonitrile and styrene on butadiene rubber latex, More specifically, it may be MABS that satisfies the above-described weight average molecular weight and molecular weight distribution.

Specifically, the graft copolymer may be prepared by a graft polymerization method of a (meth) acrylic acid ester, a vinyl cyan compound, and an aromatic vinyl compound with respect to a conjugated diene rubber latex using a molecular weight regulator.

In this case, the conjugated diene rubber latex, (meth) acrylic acid ester, vinyl cyan compound, and aromatic vinyl compound are the same as described above.

In addition, the molecular weight modifier is for controlling the molecular weight of the graft copolymer is prepared, 0.05 to 0.4 based on the total weight of the conjugated diene rubber latex and the monomer grafted to the conjugated diene rubber latex 100 parts by weight It can be used in parts by weight. If the molecular weight modifier is used too little or excessively out of the above range, the molecular weight of the graft copolymer to be produced is too small and the chemical resistance is lowered or the molecular weight is too high, the moldability may be lowered. The type of the molecular weight modifier is not particularly limited, but may be, for example, mercaptans. Specific examples may be one or more selected from the group consisting of n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan and t-dodecyl mercaptan.

The conjugated diene-based rubber latex core is not particularly limited and may be prepared by methods commonly known in the art. Specifically, one or more additives such as ion-exchanged water, an emulsifier, a polymerization initiator, an electrolyte, or a molecular weight regulator are selectively added to a conjugated diene compound, or a mixture of a conjugated diene compound and an ethylenically unsaturated compound, followed by emulsion polymerization. Preparing large diameter conjugated diene-based rubber latex (direct polymerization); Alternatively, a small diameter conjugated diene-based rubber latex may be prepared by the emulsion polymerization (step 1), and then a fusion process may be performed to prepare a large diameter conjugated diene-based rubber latex core (step 2) (coagulation polymerization method, Agglomeration polymerization).

More specifically, when the conjugated diene-based rubber latex core is prepared through a direct polymerization method, from 70 parts by weight of ion-exchanged water to 100 parts by weight of the conjugated diene-based compound or a mixture of the conjugated diene-based compound and the ethylenically unsaturated compound 120 parts by weight, emulsifier 0.2 parts to 2.5 parts by weight, 0.1 parts to 1.5 parts by weight of the polymerization initiator, 0.5 parts to 2 parts by weight of the electrolyte, and 0.1 parts to 1 parts by weight of the molecular weight modifier are collectively added to the polymerization reactor. It may be carried out by reacting at ℃ to 90 ℃. In this case, the conjugated diene-based compound and ethylenically unsaturated compound, and the molecular weight regulator may be the same material or included as described above.

The polymerization initiator is not particularly limited, but water-soluble persulfate-based polymerization initiators such as potassium persulfate, sodium persulfate or ammonium persulfate, hydrogen peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, tertiary Redox-based polymerization initiators containing peroxides such as butyl hydroperoxide and paramentane hydroperoxide as one component may be used alone or in combination.

The emulsifier is not particularly limited and may be used, for example, using one or two or more selected from the group consisting of alkyl aryl sulfonates, alkali methyl alkyl sulfates, sulfonated alkyl esters, soaps of fatty acids and alkali salts of rosin acid. Can be.

The electrolyte is not particularly limited, but for example, potassium chloride (KCl), sodium chloride (NaCl), potassium bicarbonate (KHCO ₃ ), sodium bicarbonate (NaHCO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ) , Potassium hydrogen sulfite (KHSO ₃ ), sodium hydrogen sulfite (NaHSO ₃ ), potassium pyrophosphate (K ₄ P ₂ O ₇ ), sodium pyrophosphate (Na ₄ P ₂ O ₇ ), tripotassium phosphate (K ₃ PO ₄ ), one or two or more kinds selected from the group consisting of trisodium phosphate (Na ₃ PO ₄ ), dipotassium hydrogen phosphate (K ₂ HPO ₄ ) and disodium hydrogen phosphate (Na ₂ HPO ₄ ).

The conjugated diene rubber latex core prepared by the direct polymerization method may exhibit an average particle diameter of 2000 mm 3 to 5000 mm, a gel content of 70 wt% to 95 wt%, and a swelling index of 12 to 30 as described above. In this case, the average particle diameter is measured by a dynamic laser light scattering method (Niser 370 HPL), and "Å" generally means a unit of length used to express a wavelength of electromagnetic radiation. 1 kHz is equal to 0.1 nm.

The gel content (% by weight) and the swelling index were added to methanol prepared in the conjugated diene-based rubber latex, precipitated with sulfuric acid, washed, and dried in a vacuum oven at 60 ° C. for 24 hours to obtain rubber in a rubber mass. 1 g of the slice (A) was cut into 100 g of toluene, stored in a dark room at room temperature for 48 hours, separated into a sol and a gel, and obtained by the following Equations 2 and 3 below.

[Equation 2]

[Equation 3]

In addition, when the conjugated diene-based rubber latex core is manufactured through a coagulation polymerization method, it may be carried out through steps 1 and 2 described later.

Step 1 is a step of performing an emulsion polymerization to prepare a small diameter conjugated diene-based rubber latex, the emulsion polymerization is not particularly limited and may be carried out by conventional methods known in the art. Specifically, 90 parts by weight to 130 parts by weight of ion-exchanged water, 1 part by weight to 4 parts by weight of an emulsifier, 0.1 part by weight of a polymerization initiator, in 100 parts by weight of a conjugated diene compound or a mixture of a conjugated diene compound and an ethylenically unsaturated compound To 0.6 parts by weight, 0.1 parts to 1.0 parts by weight of electrolyte, and 0.1 parts to 0.5 parts by weight of the molecular weight modifier are collectively added to the polymerization reactor and firstly reacted for 7 hours to 12 hours at a temperature range of 50 ° C to 65 ° C. After the first reaction, the method comprising the steps of adding 0.05 parts by weight to 1.2 parts by weight of the molecular weight modifier in the polymerization reactor in a batch and the temperature is raised to a temperature range of 55 ℃ to 70 ℃ to react for 5 hours to 15 hours. Can be performed by. At this time, the conjugated diene-based compound, ethylenically unsaturated compound, emulsifier, polymerization initiator, electrolyte and molecular weight modifier may be or include the material as described above.

The small-diameter conjugated diene-based rubber latex prepared by step 1 may exhibit an average particle diameter of 600 kPa to 1500 kPa, a gel content of 70 wt% to 95 wt%, and a swelling index of 12 to 30. At this time, the average particle diameter, the gel content and the swelling index can be obtained through the same method as described above.

The step 2 is a step of performing a fusion process to prepare a large diameter conjugated diene rubber latex from the prepared small diameter conjugated diene rubber latex, the fusion process is not particularly limited and commonly known in the art Although it can be carried out by the method, for example, slowly and continuously administered 2.0 parts by weight to 4.0 parts by weight of an aqueous acetic acid solution (concentration of 5 to 10%) for 1 hour while stirring in a reactor filled with 100 parts by weight of the small-diameter conjugated diene-based rubber latex. By condensing the conjugated diene rubber latex particles of the small diameter can be carried out by neutralizing by administering potassium hydroxide and stopping the stirring.

The prepared large-diameter conjugated diene-based rubber latex may exhibit the average particle diameter, gel content, and swelling index as described above.

Next, the shell containing the (meth) acrylic acid ester, the vinyl cyan compound, and the aromatic vinyl compound is an emulsifier for the (meth) acrylic acid ester, the vinyl cyan compound, and the aromatic vinyl compound to the prepared conjugated diene rubber latex core. It may be formed on the conjugated diene-based rubber latex core by selectively mixing with one or more additives, such as a polymerization initiator or a molecular weight regulator, and graft copolymerization.

Specifically, in the polymerization reactor filled with 45% to 75% by weight of the conjugated diene-based rubber latex core 25% by weight of the monomer mixture constituting the shell containing (meth) acrylic acid ester, vinyl cyan-based compound and aromatic vinyl compound 55 parts by weight, 0.05 parts by weight to 0.4 parts by weight of the molecular weight regulator, 0.1 parts by weight to 0.5 parts by weight of the emulsifier, and 0.05 parts by weight to 0.3 parts by weight of the polymerization initiator to 50 parts by weight based on 100 parts by weight of the core and the monomer mixture as a whole. The shell may be formed on the conjugated diene-based rubber latex core by copolymerizing for 3 hours to 6 hours in the temperature range of 80 ℃. At this time, the monomer mixture constituting the shell may include a (meth) acrylic acid ester, a vinyl cyan compound and an aromatic vinyl compound in a weight ratio of 20: 2: 8 to 40:10:15 as described above. In addition, by using the molecular weight regulator in the above range, as described above, it may exhibit excellent chemical resistance and may be excellent in moldability.

After the polymerization process, a process of coagulation, washing and drying may be further performed. For example, an antioxidant and a stabilizer may be added to a reactor in which polymerization is completed, and coagulation is performed by adding calcium chloride, magnesium sulfate aqueous solution or sulfuric acid aqueous solution at a temperature of 80 ° C. or higher. After dehydration and drying, the powdered graft copolymer can be obtained.

Additives such as (meth) acrylic acid esters, vinyl cyan-based compounds and aromatic vinyl compounds used to form the shells, molecular weight modifiers, emulsifiers and polymerization initiators may be or include the materials described above.

In addition, the above-mentioned substances may be administered in a batch, or a whole amount or a partial amount may be administered continuously (sequential). Moreover, such a batch administration and a continuous administration method may be mixed and used suitably.

The graft copolymer according to the present invention may have a solid coagulation content of less than 0.5% by weight. The solid coagulant is an indicator of latex stability of the graft copolymer. When the solid coagulant is 0.5% by weight or more, the latex stability may be remarkably lowered to obtain desired characteristics.

In this case, the solidified solids may be calculated according to Equation 4 below.

[Equation 4]

B) Copolymer of (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound

The copolymer of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound according to an embodiment of the present invention is a copolymer of (meth) acrylic acid ester, an aromatic vinyl compound, and a vinyl cyan compound, but is not limited thereto. However, it may be a bulk polymer prepared by bulk polymerization.

Specifically, the copolymer of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound is 55% to 70% by weight of (meth) acrylic acid ester; 20 to 30 weight percent of an aromatic vinyl compound; And it may be a bulk polymer containing 2 to 10% by weight of the vinyl cyan compound.

The copolymer of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound has a (meth) acrylic acid ester and an aromatic vinyl such that a difference in refractive index with the graft copolymer described above is less than 0.003 in order to increase the transparency of the thermoplastic resin composition. It may be desirable to appropriately adjust the weight ratio of the compound and the vinyl cyan compound. Specifically, the weight ratio of the (meth) acrylic acid ester, aromatic vinyl compound, and vinyl cyan compound may be 55: 20: 2 to 70:30:10. In this case, the (meth) acrylic acid ester, the aromatic vinyl compound, and the vinyl cyan-based compound may be included or included as described above.

In addition, the copolymer of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound may have a weight average molecular weight (Mw) of 130,000 g / mol to 300,000 g / mol. When the copolymer of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound has a weight average molecular weight in the above range, the melt index of the thermoplastic resin composition may be reduced, thereby exhibiting better environmental stress crack resistance. . In the present invention, the weight average molecular weight of the copolymer may be a polystyrene reduced molecular weight analyzed by gel permeation chromatography (GPC).

More specifically, the copolymer of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound may be methyl methacrylate-styrene-acrylonitrile copolymer (MSAN), and even more specifically, MSANs that meet the weight average molecular weight and molecular weight distribution conditions.

On the other hand, the copolymer of the (meth) acrylic acid ester, vinyl cyan-based compound and aromatic vinyl compound is not particularly limited and can be prepared by methods commonly known in the art. For example, (meth) acrylic acid ester, an aromatic vinyl compound, and a vinyl cyan compound can be prepared by block polymerization. Specifically, the bulk polymerization is 100% by weight of the monomer mixture comprising 55% to 70% by weight of the (meth) acrylic acid ester, 20% to 30% by weight of the aromatic vinyl compound, and 2% to 10% by weight of the vinyl cyan compound. Part by weight, 26 parts by weight to 30 parts by weight of the reaction medium and 0.05 parts by weight to 0.5 parts by weight of the molecular weight regulator were mixed and reacted for 2 to 4 hours while maintaining a temperature range of 140 ° C to 170 ° C. It can be carried out by removing the reacted material and reaction medium.

The reaction medium may be a conventional organic solvent, specifically, an aromatic hydrocarbon compound such as ethylbenzene, benzene, toluene, xylene; Ketone compounds such as methyl ethyl ketone and acetone; aliphatic hydrocarbon compounds such as n-hexane; Halogenated hydrocarbon compounds such as chloroform; In addition, alicyclic hydrocarbon compounds such as cyclohexane may be used.

The bulk polymerization may be performed by further including additives such as a polymerization initiator and a molecular weight regulator in addition to the above-described materials such as the monomer mixture. The additive may be a material as described above or included.

In addition, the bulk polymerization may be performed in a continuous processing machine consisting of a raw material input pump, a continuous stirring tank, a preheating tank, a volatilization tank, a polymer transfer pump, and an extrusion process.

The thermoplastic resin composition according to an embodiment of the present invention includes a copolymer of the graft copolymer and the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound as described above, and constitutes each copolymer. Each copolymer may be included in a combination such that the difference in refractive index between the two copolymers is controlled to less than 0.003 by controlling the type and content of the monomers. As such, when the refractive index difference between the two copolymers is less than 0.003 or the same refractive index, transparency of the thermoplastic resin composition may be greatly improved. In this case, the refractive index of each of the graft copolymer and the copolymer of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound is not particularly limited, but the two copolymers are notable in terms of remarkable transparency improving effect of the thermoplastic resin composition. Each may have a refractive index of 1.515 to 1.521.

In addition, the thermoplastic resin composition according to an embodiment of the present invention is a 35:65 copolymer of the graft copolymer having a refractive index difference and the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound. To 70:30, more specifically 55:45 to 60:40. As such, by including the two copolymers in an optimized content ratio, the thermoplastic resin composition may have an appropriate modulus, thereby exhibiting better impact strength and environmental stress crack resistance.

In addition, the thermoplastic resin composition according to an embodiment of the present invention is 20 wt% to 35 wt%, more specifically 25 wt% of the conjugated diene rubber latex included in the graft copolymer, based on the total weight of the thermoplastic resin composition. % To 35% by weight. By including within the above range, the thermoplastic resin composition may exhibit a significantly low flow index, and as a result it may exhibit improved environmental stress crack resistance.

The refractive index of the monomer mixture affects the transparency of the thermoplastic resin composition, where the refractive index may be controlled by the amount of the monomer used and the mixing ratio. Specifically, in the thermoplastic resin composition according to the present invention, the refractive index of butadiene forming the rubber core of the graft copolymer is about 1.518. Accordingly, in order for the thermoplastic resin composition including the same to exhibit excellent transparency, it is preferable to adjust the refractive index of the entire component of the shell grafted to the polybutadiene rubber core to a similar degree. In one example, the refractive index of each component constituting the shell is specifically about 1.49 methyl methacrylate, about 1.59 styrene and about 1.518 acrylonitrile. In addition, it is preferable to improve the transparency of the thermoplastic resin composition by adjusting the refractive index of the MSAN copolymer mixed with the graft copolymer to be almost similar to the refractive index of the graft copolymer. At the same time, it is preferable to control the acrylonitrile content and the molecular weight in order to increase the ESCR property of the thermoplastic resin composition. In addition, the content of the core rubber included in the thermoplastic resin composition affects the modulus of the thermoplastic resin composition. If the rubber content is too low, the modulus may increase to reduce the ESCR property. If the rubber content is too high, the resin composition There is a fear that the workability of the deterioration.

Accordingly, in the thermoplastic resin composition according to another embodiment of the present invention, impact resistance, transparency and environmental stress according to the control of the refractive index and the mixing ratio of the copolymer and the content of the conjugated diene rubber latex in the graft copolymer Considering good balance of uniformity, the thermoplastic resin composition may more specifically include a graft copolymer in which methyl methacrylate, acrylonitrile, and styrene are grafted to conjugated diene rubber latex; And methyl methacrylate-styrene-acrylonitrile copolymer in a weight ratio of 35:65 to 70:30, wherein the conjugated diene-based rubber latex is included in an amount of 20% to 35% by weight based on the total weight of the composition, The difference in refractive index between the graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer may be less than 0.003. At this time, the graft copolymer is prepared by graft polymerization of methyl methacrylate, acrylonitrile and styrene with a conjugated diene rubber latex using a molecular weight modifier, wherein the methyl methacrylate, acrylonitrile and Styrene is included in a weight ratio of 20: 2: 8 to 40:10:15, and the molecular weight modifier is 0.05 weight part based on 100 parts by weight of the total amount of monomers grafted to the conjugated diene rubber latex and the conjugated diene rubber latex. It may be included in parts to 0.4 parts by weight.

On the other hand, the thermoplastic resin composition according to the present invention may further include one or more additives such as lubricants, antioxidants and ultraviolet stabilizers in addition to the copolymer.

The lubricant is not particularly limited, but may be, for example, ethylene bis stearamide, polyethylene oxide wax, magnesium stearate, or a mixture thereof. The amount of the lubricant may be 0.1 part by weight to 5 parts by weight based on 100 parts by weight of the thermoplastic resin composition. In particular, it may be 0.5 parts by weight to 2 parts by weight.

The antioxidant is not particularly limited, but may be, for example, a phenolic antioxidant or a phosphate antioxidant, specifically, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) prop Stearyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and the like. The amount may be 0.5 part by weight to 2 parts by weight based on 100 parts by weight of the thermoplastic resin composition.

The UV stabilizer is not particularly limited and may be one commonly used in the art, and specifically 2 (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chloro benzotriazole [2 (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chloro benzotiazole]. The amount used may be 0.05 part by weight to 3 parts by weight with respect to 100 parts by weight of the thermoplastic resin composition, and specifically 0.2 to 1 part by weight.

The thermoplastic resin composition according to an embodiment of the present invention having the configuration as described above exhibits high environmental stress cracking resistance (ESCR) with a low flow index with excellent impact resistance and transparency.

Specifically, the thermoplastic resin composition has a haze of 3.5% or less after storage for 24 hours at 23 ° C. measured according to the method A of DIN 75201, and is manufactured in pellet form, followed by injection at 230 ° C. It is molded to produce a 1/4 "thick specimen, and the impact strength measured according to ASTM D256 (1/4", notched at 23 ℃, kgfcm / cm ² ) 20 kgfcm / cm ² ~ 30 may be kgf · cm / cm ² .

In addition, the thermoplastic resin composition is determined from a result of measuring the weight (g) of the resin melted for 10 minutes at a temperature of 220 ° C. and a 10 kg load according to ASTM D1238 after preparing the thermoplastic resin composition in pellet form. Flow index (MI) may be less than 4.0 g / 10 min.

Generally, the flow index of the transparent MABS resin used for injection of electrical / electronic products is about 10 g / 10 min to 50 g / 10 min, and the flow index of the transparent MABS for extrusion used for sheets is 4.5. g / 10 min to 8 g / 10min. In addition, when the flow index exceeds 4.0g / 10min, the molecular weight is insufficient and the environmental stress uniformity of the thermoplastic resin is lowered. The thermoplastic resin composition according to the present invention has a flow index of 4 g / 10 min or less, more specifically 3.5 g / 10 min or less, even more specifically 1 g / 10 min to 3 g / 10 min, and is excellent in high shear test. It can show environmental stress uniformity.

The flow index of the thermoplastic resin composition may be mainly determined by the content of the vinyl cyanide compound of the copolymer, the molecular weight of the copolymer, and the content of the conjugated diene-based latex, and particularly, the content of the conjugated diene-based latex in the thermoplastic resin composition is large. get affected. As described above, the thermoplastic resin composition according to the exemplary embodiment of the present invention controls the content of the conjugated diene rubber latex to 20 wt% to 35 wt%, more specifically 25 wt% to 35 wt% based on the total weight of the composition. As a result, a flow index of 4.0 g / 10 min or less, which is significantly lower than that of a conventional injection molding rubber composition, can be exhibited. Furthermore, the flow index of the thermoplastic resin composition may be further reduced by further controlling the content of the vinyl cyan compound and the molecular weight of the copolymer in each copolymer constituting the thermoplastic resin composition.

In addition, according to another embodiment of the present invention provides a thermoplastic resin molded article prepared from the thermoplastic resin composition.

The thermoplastic resin molded article prepared from the thermoplastic resin composition according to the present invention not only has excellent impact resistance and transparency, but also has high environmental stress crack resistance (chemical resistance), thereby providing excellent impact resistance, transparency and environmental stress crack resistance ( Chemistry), which may be useful in the manufacture of materials, in particular medical products.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following Examples and Experimental Examples are provided to illustrate the present invention, and the scope of the present invention is not limited only to these examples.

Example 1

1) Preparation of methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS)

a) Preparation of conjugated diene rubber latex core of small diameter

110 parts by weight of ion-exchanged water, 100 parts by weight of 1,3-butadiene, 1.2 parts by weight of potassium rosin salt and 1.5 parts by weight of potassium oleate salt, 0.1 part by weight of sodium carbonate as electrolyte in a nitrogen-substituted polymerization reactor (autoclave); 0.5 parts by weight of potassium bicarbonate, 0.3 parts by weight of t-dodecyl mercaptan (TDDM) as a molecular weight regulator, the reaction temperature was raised to 55 ℃ and 0.3 parts by weight of potassium persulfate as a polymerization initiator to initiate the reaction for 10 hours Reacted. Thereafter, 0.05 parts by weight of tertiary dodecyl mercaptan was further administered as a molecular weight regulator, and the reaction was terminated after further reacting for 8 hours by raising the temperature to 65 ° C. The obtained conjugated diene rubber latex had an average particle diameter of 1000 mm 3, a gel content of 90 wt%, and an swelling index of 18. At this time, the average particle diameter, the gel content and the swelling index were obtained through the above-described method.

b) Preparation of large diameter conjugated diene rubber latex cores

In order to manufacture a large diameter conjugated diene rubber latex core from the small diameter conjugated diene rubber latex prepared in a), 100 parts by weight of the minor diameter conjugated diene rubber latex was added to a reaction tank, and a stirring speed of 10 rpm and 30 After controlling to a temperature of ℃ and 3.0 parts by weight of 7% acetic acid aqueous solution was slowly added for 1 hour, neutralized with aqueous potassium hydroxide solution and the stirring was stopped. Thereafter, it was left for 30 minutes to obtain a large diameter conjugated diene rubber latex core. The prepared large-diameter conjugated diene-based rubber latex core exhibited an average particle diameter of 3000 mm 3, a gel content of 90 wt%, and a swelling index of 17. At this time, the average particle diameter, the gel content and the swelling index were obtained through the above-described method.

c) manufacture of shells

90 parts by weight of ion-exchanged water and 0.1 weight of alkyl aryl sulfonate salt (Dowfax ™, manufactured by Dow) in 50% by weight of the large diameter conjugated diene rubber latex core prepared in b) in a nitrogen-substituted polymerization reactor having an internal temperature of 50 ° C. Part, 25% by weight of the monomer mixture constituting the shell, 0.1 part by weight of t-dodecylmercaptan, 0.048 part by weight of sodium tetrapyrophosphate, 0.012 part by weight of dextrose, 0.001 part by weight of ferrous sulfide, 0.04 weight of cumene hydroperoxide The reaction was initiated while the batch was dosed and the temperature was raised to 73 ° C. over 1 hour. And 70 parts by weight of ion-exchanged water, 0.2 parts by weight of alkyl aryl sulfonate salt, 25% by weight of the monomer mixture constituting the shell, 0.1 part by weight of t-dodecylmercaptan, 0.048 part by weight of sodium pyrophosphate, and 0.012 weight of dextrose. Part 1, 0.001 parts by weight of ferrous sulfide and 0.1 parts by weight of cumene hydroperoxide were continuously administered for 3 hours, and then heated to 76 ° C. to mature for 1 hour, and the reaction was completed to complete 99% of polymerization conversion and solidified solids. 0.1 wt% of methyl methacrylate-acrylonitrile-butadiene-styrene copolymer was prepared. The parts by weight are shown based on 100 parts by weight of the total mixture of monomers constituting the conjugated diene-based rubber latex core and the shell, and the monomer mixtures constituting the shell are methyl methacrylate, styrene and acrylonitrile 32.68: 11.32 It mixes in the weight ratio of: 6.0. The prepared methyl methacrylate-acrylonitrile-butadiene-styrene copolymer was coagulated with an aqueous calcium chloride solution, washed and dried to obtain a methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer in powder form. .

2) Preparation of Methyl Methacrylate-Styrene-Acrylonitrile Copolymer (MSAN)

To 100 parts by weight of a monomer mixture comprising 68.4% by weight of methyl methacrylate, 26.6% by weight of styrene and 5% by weight of acrylonitrile, 30 parts by weight of toluene and 0.15 parts by weight of di-t-dodecyl mercaptan were added to the raw material mixture. To prepare a raw material mixture was continuously added to the reaction tank so that the average reaction time is 3 hours. At this time, the reaction temperature was maintained at 148 ℃. The polymer solution discharged from the reactor was heated in a preheating bath and volatilized unreacted monomer in a volatilization tank to obtain a methyl methacrylate-styrene-acrylonitrile copolymer, and the polymer was maintained at 210 ° C. Methyl methacrylate-styrene-acrylonitrile copolymer in pellet form was prepared using a transfer pump extrusion machine.

3) Preparation of Thermoplastic Resin Composition

Methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer prepared in 1) and methyl methacrylate-styrene-acrylonitrile copolymer prepared in 2), total content of the two copolymers 100 weight 0.2 parts by weight of lubricant, 0.1 parts by weight of antioxidant, and 0.1 parts by weight of UV stabilizer were added and kneaded, and a pellet-type thermoplastic resin composition was prepared using a twin screw extruder at 210 ° C. In this case, the methyl methacrylate-acrylonitrile-butadiene-styrene copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer were used in a weight ratio of 58:42.

Example 2

In Example 1, 3), the methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer were obtained in an amount of 48:52 instead of 58:42. A thermoplastic resin composition in a pellet form was obtained by the same method as Example 1 except for using the weight ratio.

Example 3

Through the same method as in Example 1, except that the total amount of the t-dodecyl mercaptan in Example 1) 1) -c) was divided by two so as to be 0.05 parts by weight instead of 0.2 parts by weight. A thermoplastic resin composition in pellet form was obtained.

Example 4

Through the same method as in Example 1, except that the total amount of the t-dodecyl mercaptan in Example 1) 1) -c) was divided into 2 parts by weight so as to be 0.4 parts by weight instead of 0.2 parts by weight. A thermoplastic resin composition in pellet form was obtained.

Example 5

As the monomer mixture constituting the shell in Example 1) -c), a mixture of methyl methacrylate, styrene and acrylonitrile in a weight ratio of 35.66: 12.34: 2.0 was used, and the t-dode A thermoplastic resin composition in a pellet form was obtained in the same manner as in Example 1, except that 0.15 parts by weight of the total amount of the silmercaptan was divided into two parts of 0.3 parts by weight instead of 0.2 parts by weight.

Example 6

Except that the total amount of the t-dodecyl mercaptan in Example 1) 1) -b) was divided into two to be 0.03 parts by weight instead of 0.2 parts by weight of pellets through the same method as in Example 1 A thermoplastic resin composition was obtained.

Comparative Example 1

In Example 1, 3), the methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer were substituted with a weight ratio of 34:66 instead of 58:42. A thermoplastic resin composition in a pellet form was obtained by the same method as Example 1 except for using the weight ratio.

Comparative Example 2

In Example 1, 3), the methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer were used instead of the weight ratio of 58:42. A thermoplastic resin composition in a pellet form was obtained by the same method as Example 1 except for using the weight ratio.

Comparative Example 3

The same method as in Example 1 was repeated except that the total amount of t-dodecyl mercaptan used in Example 1 was 0.5 parts by weight so that the total amount of t-dodecyl mercaptan was 0.5 parts by weight instead of 0.2 parts by weight. Through the thermoplastic resin composition of the pellet form was obtained.

Comparative Example 4

Except for using the monomer mixture constituting the shell in Example 1) -c) of Example 1, methylmethacrylate, styrene and acrylonitrile were mixed at a weight ratio of 28.23: 15.77: 6.0. Through the same method as 1 to obtain a thermoplastic resin composition in the form of pellets.

Comparative Example 5

As the monomer mixture constituting the shell in Example 1) -c), a mixture of methyl methacrylate, styrene and acrylonitrile in a weight ratio of 35.66: 12.34: 2.0 was used, and the t-dode A thermoplastic resin composition in a pellet form was obtained in the same manner as in Example 1, except that 0.3 parts by weight of the total amount of the silmercaptan was used in two portions so as to be 0.6 parts by weight instead of 0.2 parts by weight.

Comparative Example 6

In Example 1) -c), the total amount of t-dodecyl mercaptan used is divided into two portions so that the total amount of t-dodecyl mercaptan is 0.5 parts by weight, not 0.2 parts by weight, and 0.25 parts by weight is used. The methacrylate-acrylonitrile-butadiene-styrene graft copolymer and the methylmethacrylate-styrene-acrylonitrile copolymer were used in a weight ratio of 30:70 instead of 58:42, except that Through the same method as in Example 1, a thermoplastic resin composition in a pellet form was obtained.

Comparative Example 7

Instead of the monomer mixture used in the preparation of 2) methylmethacrylate-styrene-acrylonitrile copolymer (MSAN) of Example 1, 64% by weight of methyl methacrylate, 31% by weight of styrene and 5% by weight of acrylonitrile Except for using the monomer mixture containing%, the thermoplastic resin composition in the form of pellets was obtained through the same method as in Example 1.

Comparative Example 8

In Example 1, 3), the methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer were obtained in an amount of 39:61 instead of 58:42. A thermoplastic resin composition in a pellet form was obtained by the same method as Example 1 except for using the weight ratio.

Table 1

	MABS graft copolymer (A)			MSAN copolymer (B)		Mixed weight ratio of A: B
	Rubber content (% by weight)	MMA: S: AN weight ratio	Molecular weight regulator content 1) (parts by weight)	MMA: S: AN weight ratio	Molecular weight regulator content 2) (parts by weight)
Example 1	28.9	32.68: 11.32: 6.0	0.2	68.4: 26.6: 5	0.1	58:42
Example 2	23.9	32.68: 11.32: 6.0	0.2	68.4: 26.6: 5	0.1	48:52
Example 3	28.9	32.68: 11.32: 6.0	0.05	68.4: 26.6: 5	0.1	58:42
Example 4	28.9	32.68: 11.32: 6.0	0.4	68.4: 26.6: 5	0.1	58:42
Example 5	28.9	35.66: 12.34: 2.0	0.3	68.4: 26.6: 5	0.1	58:42
Example 6	28.9	32.68: 11.32: 6.0	0.03	68.4: 26.6: 5	0.1	58:42
Comparative Example 1	16.9	32.68: 11.32: 6.0	0.2	68.4: 26.6: 5	0.1	34:66
Comparative Example 2	35.9	32.68: 11.32: 6.0	0.2	68.4: 26.6: 5	0.1	72:28
Comparative Example 3	28.9	32.68: 11.32: 6.0	0.5	68.4: 26.6: 5	0.1	58:42
Comparative Example 4	28.9	28.23: 15.77: 6.0	0.2	68.4: 26.6: 5	0.1	58:42
Comparative Example 5	28.9	35.66: 12.34: 2.0	0.6	68.4: 26.6: 5	0.1	58:42
Comparative Example 6	14.9	32.68: 11.32: 6.0	0.5	68.4: 26.6: 5	0.1	30:70
Comparative Example 7	28.9	32.68: 11.32: 6.0	0.2	64: 31: 5	0.1	58:42
Comparative Example 8	19.5	32.68: 11.32: 6.0	0.2	68.4: 26.6: 5	0.1	39:61

In Table 1, the rubber content is weight% based on the total weight of the thermoplastic resin composition, and the content of the molecular weight regulator ¹⁾ is 100 parts by weight of the total sum of the monomers grafted onto the conjugated diene rubber latex and the conjugated diene rubber latex. Relative weight ratio, and the content of the molecular weight modifier ²⁾ is relative weight ratio to 100 parts by weight total of the monomers forming the MSAN copolymer.

Experimental Example 1

The refractive index values of the copolymers prepared in Examples 1 to 6 and Comparative Examples 1 to 8 were measured.

The refractive index of the graft copolymer was calculated according to the following Equation 1 using the refractive index and the content of each polymer of the graft copolymer composition, and the refractive index of the polymer constituting the copolymer was prepared with a specimen having a thickness of 40 μm, It was measured by irradiation of 450 nm light using an Abbe refractor. The results are shown in Table 2 below.

[Equation 1]

RI = ∑ (Wti × RIi)

In Formula 1, Wti is the weight fraction (%) of each component (or polymer) in the graft copolymer, and RIi is the refractive index of the graft copolymer-forming polymer.

TABLE 2

	MABS graft copolymer (A)				MSAN copolymer (B)
	Refractive Index of Conjugated Diene Rubber Latex Core	Refractive index of the shell	Refractive Index of MABS Graft Copolymer	Solid coagulant of MABS (% by weight)	MSAN refractive index	Mw of MSAN (g / mol)
Example 1	1.518	1.518	1.518	0.10	1.518	146,000
Example 2	1.518	1.518	1.518	0.10	1.518	146,000
Example 3	1.518	1.518	1.518	0.14	1.518	146,000
Example 4	1.518	1.518	1.518	0.09	1.518	146,000
Example 5	1.518	1.518	1.518	0.08	1.518	146,000
Example 6	1.518	1.518	1.518	0.18	1.518	146,000
Comparative Example 1	1.518	1.518	1.518	0.10	1.518	146,000
Comparative Example 2	1.518	1.518	1.518	0.10	1.518	146,000
Comparative Example 3	1.518	1.518	1.518	0.08	1.518	146,000
Comparative Example 4	1.518	1.5249	1.5215	0.15	1.518	146,000
Comparative Example 5	1.518	1.5158	1.5169	0.12	1.518	146,000
Comparative Example 6	1.518	1.518	1.518	0.10	1.518	146,000
Comparative Example 7	1.518	1.518	1.518	0.10	1.5224	145,000
Comparative Example 8	1.518	1.518	1.518	0.10	1.518	146,000

Experimental Example 2

In order to analyze the impact resistance, transparency, environmental stress crack resistance (chemical resistance) and fluidity of each thermoplastic resin composition prepared in Examples 1 to 6 and Comparative Examples 1 to 8, impact strength, haze, Environmental stress crack resistance and flow index were measured, respectively, and the results are shown in Table 3 below.

1) impact strength

In order to compare and analyze the impact resistance of each thermoplastic resin composition prepared in Examples 1 to 6 and Comparative Examples 1 to 8, the impact strength of each thermoplastic resin composition was measured.

Impact strength is produced by injection molding the pellets of the thermoplastic resin composition at 230 ℃ to a specimen 1/4 "thick, according to ASTM D256 (1/4", notched at 23 ℃, kgfcm / cm ² ) It was carried out by.

2) Flow index (MI)

In order to compare and analyze the fluidity of each thermoplastic resin composition prepared in Examples 1 to 6 and Comparative Examples 1 to 8, the flow index (melt index) of each thermoplastic resin composition was measured.

The flow index measured the weight (g) of the resin melted for 10 minutes under pellets of each thermoplastic resin composition at a temperature of 220 ° C. and a 10 kg load according to ASTM D1238.

3) Environmental stress crack resistance (chemical resistance)

In order to analyze and analyze the environmental stress crack resistance (ESCR) of each thermoplastic resin composition prepared in Examples 1 to 6 and Comparative Examples 1 to 8, the environmental stress crack resistance of each thermoplastic resin composition was measured.

Environmental stress crack resistance injection molding the pellets of the thermoplastic resin composition at 230 ℃ to produce each 1/4 "thick specimens, strain Jig of 1.5% at room temperature (about 25 ℃) in accordance with ASTM D1693 It was installed in (Strain Zig), soaked soybean oil in the center of the specimen and prevented for 2 days, and the change of the specimen was observed after 2 days.

<Evaluation Criteria>

○: No change in the specimen. Excellent environmental stress crack resistance

(Triangle | delta): A crack is observed in a test piece.

×: the specimen completely cracked, poor environmental stress crack resistance

4) Haze

In order to compare and analyze the transparency of each thermoplastic resin composition prepared in Examples 1 to 6 and Comparative Examples 1 to 8, the haze of each thermoplastic resin composition was measured.

The haze was injection molded pellets of the thermoplastic resin composition at 230 to prepare each specimen having a 1/4 "thickness, and measured after storage for 24 hours at room temperature (about 23 ° C) in accordance with the method A of DIN 75201. .

TABLE 3

division	Impact strength (kgfcm / cm 2 )	Flow index (g / 10min)	Transparency (Haze,%)	Environmental Stress Cracking Resistance
Example 1	26.2	2.3	2.5	○
Example 2	20.8	2.9	2.2	○
Example 3	28.4	1.9	2.7	○
Example 4	23.1	2.6	2.3	○
Example 5	14.6	3.5	2.5	○
Example 6	29.0	0.7	3.9	○
Comparative Example 1	19.6	6.9	1.8	×
Comparative Example 2	38.9	0.2 (poor tensile strength)	4.5	○
Comparative Example 3	24.2	4.1	2.2	△
Comparative Example 4	25.5	2.5	9.8	○
Comparative Example 5	15.5	6.5	2.7	△
Comparative Example 6	18.0	20.6	1.8	×
Comparative Example 7	25.0	2.6	11.5	○
Comparative Example 8	21.5	5.4	2.0	×

As a result, the thermoplastic resins of Examples 1 to 6 according to the present invention are compared with the thermoplastic resins of Comparative Examples 1 to 8 without any bias in the characteristics of impact strength, flow index, transparency and environmental stress crack resistance. It was confirmed that the balance exhibits improved properties. However, in the case of Example 6 in which the molecular weight modifier was used in a slightly lower content, the flow index was significantly lower than that of Examples 1 to 5, indicating a slightly deteriorated processability, and high haze value compared to Examples 1 to 5 in terms of transparency. Indicated.

Specifically, prepared by mixing methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer (MABS) and methyl methacrylate-styrene-acrylonitrile copolymer (MSAN) within a ratio range according to the present invention. As a result of comparing the thermoplastic resins of Examples 1 to 6 with the thermoplastic resins of Comparative Examples 1 and 2 which did not satisfy the mixing ratio condition and rubber content condition of the MABS and MSAN, Although the thermoplastic resin was excellent in transparency, the environmental stress crack resistance was greatly lowered as the flow index range of the thermoplastic resin composition of the present invention was greatly exceeded. In addition, the thermoplastic resin of Comparative Example 2 in which the MABS was used in an excessive amount was excellent in impact strength and environmental stress crack resistance, but the transparency was greatly decreased, and poor tensile strength was shown.

In addition, the thermoplastic resins of Comparative Examples 3 and 5, which do not satisfy the flow index conditions of the thermoplastic resin composition according to the present invention, and in which the molecular weight modifier is used in excess of the range of the present invention in the preparation of the MABS, have an environmental stress resistance. Cracking property fell.

In addition, the mixture of MABS and MSAN in the ratio of the range according to the present invention was prepared, but the mixing ratio conditions of the monomers constituting the MABS in the preparation of the MABS does not meet the mixing ratio conditions defined in the present invention thermoplasticity Resin greatly reduced transparency as the difference in refractive index between MABS and MSAN constituting the resin composition exceeded 0.003.

In addition, the thermoplastic resin of Comparative Example 6, which does not satisfy the flow index conditions of the copolymers presented in the present invention and is out of the rubber content range and the molecular weight modifier content range in the manufacture of MABS, has an impact strength lowered, Stress cracking was significantly reduced.

In addition, the resin composition of Comparative Example 7 in which the mixing ratio condition of the monomer of MSAN does not satisfy the mixing ratio condition defined in the present invention has a large transparency as the difference in refractive index between MABS and MSAN constituting the resin composition exceeds 0.003. Degraded.

In addition, the resin composition of Comparative Example 8, which did not satisfy the flow index condition of the copolymer proposed in the present invention, and did not satisfy the rubber content condition in the thermoplastic resin composition, significantly lowered the environmental stress crack resistance.

This is because the composition and mixing ratio of each copolymer according to the present invention, the difference in refractive index between the two copolymers, and the control of the flow index of the thermoplastic resin composition, the impact strength, transparency and environmental stress crack resistance of the thermoplastic resin composition The present invention is not limited to the characteristics, but represents an important factor capable of improving all the above characteristics. Therefore, the thermoplastic resin composition according to the present invention and the thermoplastic resin molded article prepared therefrom may be useful as a material of a material industry, in particular, a medical product, where impact strength, transparency, and environmental stress crack resistance (chemical resistance) are simultaneously required. .

Claims (18)

1. Graft copolymers (A) in which a (meth) acrylic acid ester, a vinyl cyan compound and an aromatic vinyl compound are graft polymerized onto a conjugated diene rubber latex; And a copolymer (B) of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound in a weight ratio of 35:65 to 70:30,

   In the light irradiation in the wavelength range of 450 nm to 680 nm, the difference in refractive index between the graft copolymer (A) and the copolymer (B) of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound is less than 0.003,

   A thermoplastic resin composition exhibiting a flow index of 4.0 g / 10 min or less when measured by a flow index according to ASTM D1238.
2. The method of claim 1,

   The conjugated diene-based rubber latex is a thermoplastic resin composition comprising 20 to 35% by weight relative to the total weight of the thermoplastic resin composition.
3. The method of claim 1,

   The conjugated diene rubber latex is a conjugated diene compound homopolymer or a copolymer of a conjugated diene compound and an ethylenically unsaturated compound.
4. The method of claim 1,

   The (meth) acrylic acid ester in the copolymer (B) of the graft copolymer (A) and the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound is independently methyl acrylate, ethyl acrylate, Propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate and 2-ethylhexyl methacrylate A thermoplastic resin composition comprising any one or a mixture of two or more selected from the group consisting of the rate.
5. The method of claim 1,

   The aromatic vinyl compounds in the copolymer (B) of the graft copolymer (A) and the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound are each independently styrene, α-methylstyrene, vinyltoluene, A thermoplastic resin composition comprising any one or a mixture of two or more selected from the group consisting of alkyl styrene substituted with C _1-3 alkyl groups and styrene substituted with halogen.
6. The method of claim 1,

   The vinyl cyan compound in the copolymer (B) of the graft copolymer (A) and the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound is acrylonitrile, methacrylonitrile and derivatives thereof. A thermoplastic resin composition comprising any one or a mixture of two or more selected from the group consisting of.
7. The method of claim 1,

   The graft copolymer (A) is 45 to 75% by weight of the conjugated diene rubber latex core; And a core-shell structure comprising 25 wt% to 55 wt% of a shell comprising a (meth) acrylic acid ester, a vinyl cyan compound, and an aromatic vinyl compound grafted onto the core.
8. The method of claim 7, wherein

   The difference in refractive index between the conjugated diene rubber latex core and the shell is less than 0.003 thermoplastic resin composition.
9. The method of claim 7, wherein

   The conjugated diene rubber latex core is a thermoplastic resin composition having an average particle diameter of 2000 GPa to 5000 GPa, a gel content of 70% to 95% by weight and a swelling index of 12 to 30.
10. The method of claim 1,

    The graft copolymer (A) is prepared by graft polymerization of a (meth) acrylic acid ester, a vinyl cyan compound and an aromatic vinyl compound with respect to a conjugated diene rubber latex using a molecular weight modifier,

    The (meth) acrylic acid ester, vinyl cyan compound and aromatic vinyl compound are used in a weight ratio of 20: 2: 8 to 40:10:15,

    The molecular weight modifier is a thermoplastic resin composition is used in 0.05 parts by weight to 0.4 parts by weight based on 100 parts by weight of the total of the conjugated diene rubber latex and the monomer grafted to the conjugated diene rubber latex.
11. The method of claim 10,

    The molecular weight modifier is a thermoplastic resin composition comprising any one or two or more selected from the group consisting of n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan and t-dodecyl mercaptan.
12. The method of claim 1,

    The solid resin contained in the graft copolymer (A) is less than 0.5% by weight of the thermoplastic resin composition.
13. The method of claim 1,

    The graft copolymer (A) is a methyl methacrylate-acrylonitrile-butadiene-styrene copolymer.
14. The method of claim 1,

    The copolymer (B) of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound

    55% to 70% by weight of (meth) acrylic acid ester;

    20 to 30 weight percent of an aromatic vinyl compound; And

    2 to 10 wt% of the vinyl cyan compound.
15. The method of claim 1,

    The copolymer (B) of the (meth) acrylic acid ester-aromatic vinyl compound-vinyl cyan compound is a methyl methacrylate-styrene-acrylonitrile copolymer.
16. The method of claim 1,

    The thermoplastic resin composition whose haze measured according to the method A of DIN 75201 is 2.5% or less.
17. Graft copolymers in which methyl methacrylate, acrylonitrile and styrene are graft-polymerized with respect to conjugated diene rubber latex; And methyl methacrylate-styrene-acrylonitrile copolymer in a weight ratio of 35:65 to 70:30,

    Containing the conjugated diene rubber latex 20 to 35% by weight based on the total weight of the composition,

    In the light irradiation in the wavelength range of 450 nm to 680 nm, the difference in refractive index between the graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer is less than 0.003,

    The graft copolymer is prepared by graft polymerization of methyl methacrylate, acrylonitrile and styrene using a molecular weight modifier with respect to conjugated diene rubber latex,

    The methyl methacrylate, acrylonitrile and styrene are used in a weight ratio of 20: 2: 8 to 40:10:15, and the molecular weight modifier of the monomer grafted to the conjugated diene rubber latex and the conjugated diene rubber latex A thermoplastic resin composition used in an amount of 0.05 to 0.4 parts by weight based on 100 parts by weight in total.
18. A thermoplastic resin molded article prepared from the thermoplastic resin composition according to any one of claims 1 to 17.