CN111201279A

CN111201279A - Thermoplastic resin composition and molded article formed therefrom

Info

Publication number: CN111201279A
Application number: CN201880063130.6A
Authority: CN
Inventors: 任晟午; 金珢珍; 秋东辉; 权宁喆
Original assignee: Lotte Chemical Corp
Current assignee: Lotte Chemical Corp
Priority date: 2017-10-19
Filing date: 2018-08-30
Publication date: 2020-05-26
Also published as: JP2021500423A; WO2019078479A1; JP7145941B2; KR101925728B1

Abstract

本发明的热塑性树脂组合物包括：(A)橡胶改性的乙烯基类接枝共聚物；(B)重均分子量为约100,000g/mol‑500,000g/mol的第一芳族乙烯基‑氰基乙烯基类共聚物；(C)重均分子量为约4,000,000g/mol或更大的第二芳族乙烯基‑氰基乙烯基类共聚物；和(D)氧化锌，其中(C)和(D)的重量比为约1:约0.5至约1:约5。The thermoplastic resin composition of the present invention comprises: (A) a rubber-modified vinyl-based graft copolymer; (B) a first aromatic vinyl-cyanide having a weight average molecular weight of about 100,000 g/mol-500,000 g/mol (C) a second aromatic vinyl-cyanovinyl-based copolymer having a weight average molecular weight of about 4,000,000 g/mol or greater; and (D) zinc oxide, wherein (C) and The weight ratio of (D) is from about 1 : about 0.5 to about 1 : about 5.

Description

Thermoplastic resin composition and molded article formed therefrom

Technical Field

The present invention relates to a thermoplastic resin composition and a molded article formed therefrom. More particularly, the present invention relates to a thermoplastic resin composition having good properties in terms of antibacterial effect, vacuum formability, and mechanical strength, and a molded article formed therefrom.

Background

In general, rubber-modified aromatic vinyl copolymer resins, such as acrylonitrile-butadiene-styrene copolymer (ABS) resins, are mainly used as resins for refrigerators. In particular, unlike general ABS resins, extruded ABS resins for refrigerators are required to undergo additional processing, i.e., vacuum forming, and thus are required to have good processability. In addition, such a material for a refrigerator is required to have antibacterial properties to be suitable for storage of foods.

In order to impart antibacterial properties to such a resin for a refrigerator, a method of adding an antibacterial agent to the resin has been proposed. Although organic antibacterial agents are relatively low in price and can provide good antibacterial effects even in a small amount, they are sometimes toxic to humans, effective only for certain bacteria, and easily decompose and lose antibacterial properties when processed at high temperatures. In addition, organic antibacterial agents cause discoloration after processing and cannot have long-term antibacterial durability due to problems associated with dissolution.

Inorganic antibacterial agents are antibacterial agents containing metal components such as silver (Ag) and copper (Cu), and are widely used for the preparation of antibacterial thermoplastic resin compositions (antibacterial resins) due to their good thermal stability. However, since the inorganic antibacterial agent needs to be used in a large amount due to its lower antibacterial activity than the organic antibacterial agent, and has disadvantages of relatively high price, difficulty in uniform dispersion at the time of processing, and discoloration due to metal components, the inorganic antibacterial agent is used in a limited range of applications. Further, inorganic antimicrobial agents can affect the vacuum formability of the resin. In response to the trend toward large capacity and reduced thickness of refrigerator products, there is a demand for thermoplastic resin compositions capable of exhibiting good properties in terms of antibacterial effect, vacuum moldability and mechanical strength.

The background art of the present invention is disclosed in korean patent laid-open publication No. 10-2009-0073453.

Disclosure of Invention

[ problem ] to provide a method for producing a semiconductor device

An object of the present invention is to provide a thermoplastic resin composition having good properties in terms of antibacterial effect, vacuum moldability and mechanical strength, and a molded article formed therefrom.

It is another object of the present invention to provide a thermoplastic resin composition having good low-odor properties and a molded article formed therefrom.

The above and other objects of the present invention will become apparent from the detailed description of the embodiments below.

[ technical solution ] A

One aspect of the present invention relates to a thermoplastic resin composition. The thermoplastic resin composition comprises: (A) rubber-modified vinyl graft copolymers; (B) a first aromatic vinyl-vinyl cyanide copolymer having a weight average molecular weight of about 100,000g/mol to about 500,000 g/mol; (C) a second aromatic vinyl-vinyl cyanide copolymer having a weight average molecular weight of about 4,000,000g/mol or more; and (D) zinc oxide, wherein the weight ratio of (C) to (D) ranges from about 1:0.5 to about 1: 5.

In one embodiment, the thermoplastic resin composition may include: about 100 parts by weight of a base resin comprising about 10 to about 70 wt% of a rubber-modified vinyl graft copolymer (A) and about 30 to about 90 wt% of a first aromatic vinyl-vinyl cyanide copolymer (B); about 1 to about 10 parts by weight of a second aromatic vinyl-vinyl cyanide copolymer (C); and about 2 to about 10 parts by weight of zinc oxide (D).

In one embodiment, the rubber-modified vinyl graft copolymer (a) may be obtained by graft copolymerizing a monomer mixture including an aromatic vinyl monomer and a vinyl cyanide monomer to a diene rubber polymer.

In one embodiment, the diene rubber polymer may have an average particle size of about 0.1 μm to about 0.4. mu.m.

In one embodiment, the weight average molecular weight of the second aromatic vinyl-vinyl cyanide copolymer (C) may be about 4,000,000g/mol to about 10,000,000 g/mol.

In one embodiment, the zinc oxide (D) may have a peak intensity ratio (B/a) of about 0.01 to about 10 in photoluminescence measurements, where a indicates a peak in a wavelength range of 370nm to 390nm, and B indicates a peak in a wavelength range of 450nm to 600 nm.

In one embodiment, the zinc oxide (D) may have a peak intensity ratio (B/a) of about 0.01 to about 1 in photoluminescence measurement, where a indicates a peak in a wavelength range of 370nm to 390nm, and B indicates a peak in a wavelength range of 450nm to 600 nm.

In one embodiment, the BET specific surface area of zinc oxide (D) may be about 15m²(ii) g or less.

In one embodiment, in an X-ray diffraction (XRD) analysis, as calculated from formula 4, the peak position (2 θ) of the zinc oxide (D) may be in a range of about 35 ° to about 37 °, and the crystallite size may be about 35 ° to about 37 °

To about

[ formula 4]

Where K is the shape factor, λ is the X-ray wavelength, β is the FWHM value (degrees) of the X-ray diffraction peak, and θ is the peak position degree.

In one embodiment, the zinc oxide (D) may have an average particle size (D50) of about 0.5 μm to about 3 μm.

In one embodiment, the thermoplastic resin composition may satisfy formula 1 and formula 2:

[ equation 1]

6kg/cm²≤TS₁₅₀≤20kg/cm²

Wherein TS₁₅₀Represents the tensile strength of the thermoplastic resin composition measured at a strain rate of 150mm/min after the thermoplastic resin composition is left at 150 ℃ for 3 minutes according to ASTM D638, and

[ formula 2]

485kg/cm²≤TS₂₃≤600kg/cm²

Wherein TS₂₃Represents the tensile strength of the thermoplastic resin composition measured at 23 ℃ at a strain rate of 5mm/min according to ASTM D638.

In one embodiment, the antibacterial activity of the thermoplastic resin composition against staphylococcus aureus may be about 2 to about 5, and the antibacterial activity against escherichia coli may be about 2 to about 5, as measured according to JIS Z2801 on 5cm × 5cm samples, respectively, inoculated with staphylococcus aureus and escherichia coli, and calculated according to formula 3:

[ formula 3]

Log (M1/M2)

Wherein M1 is the number of bacteria measured on a blank sample after 24 hours of incubation at 35 ℃ and 90% RH, and M2 is the number of bacteria measured on each sample of the thermoplastic resin composition after 24 hours of incubation at 35 ℃ and 90% RH.

In one embodiment, the total volatile organic compound detection area of the thermoplastic resin composition can be from about 200 area/g to about 500 area/g as measured by HS-SPMEGC/MS after collecting the volatile organic compounds at 120 ℃ for 300 minutes.

In one embodiment, the residual volatile content of the thermoplastic resin composition can be from about 800ppm to about 1,200ppm as measured by GC/MS at 250 ℃.

Another aspect of the present invention relates to a molded article formed from the above thermoplastic resin composition.

In one embodiment, the molded article may be formed by vacuum forming, and may be used for refrigerator interior parts.

[ PROBLEMS ] the present invention

The present invention provides a thermoplastic resin composition having good properties in terms of antibacterial effect, vacuum moldability and mechanical strength while exhibiting excellent low-odor properties, and a molded article formed therefrom.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The thermoplastic resin composition according to the present invention comprises: (A) rubber-modified vinyl graft copolymers; (B) a first aromatic vinyl-vinyl cyanide copolymer having a weight average molecular weight of about 100,000g/mol to about 500,000 g/mol; (C) a second aromatic vinyl-vinyl cyanide copolymer having a weight average molecular weight of about 4,000,000g/mol or more; and (D) zinc oxide.

(A) Rubber modified vinyl graft copolymers

The rubber-modified vinyl graft copolymer according to one embodiment of the present invention is used to improve impact resistance of a thermoplastic resin composition, and may be obtained by graft-polymerizing a monomer mixture including an aromatic vinyl monomer and a vinyl cyanide monomer to a diene rubber polymer. For example, the rubber-modified vinyl graft copolymer may be obtained by graft-copolymerizing a monomer mixture including an aromatic vinyl monomer and a vinyl cyanide monomer to the diene rubber polymer, wherein the monomer mixture may further include a monomer for imparting processability and heat resistance as needed. Here, the polymerization may be carried out by any suitable polymerization method known in the art, such as emulsion polymerization or suspension polymerization.

In some embodiments, examples of the diene rubber polymer may include polybutadiene, poly (styrene-butadiene), and poly (acrylonitrile-butadiene), but are not limited thereto. These may be used alone or as a mixture thereof. For example, the diene rubber polymer may be a butadiene rubber, such as polybutadiene.

In some embodiments, the diene rubber polymer (rubber particles) may have an average (Z-average) particle size of about 0.1 μm to about 0.4 μm, for example about 0.2 μm to about 0.4 μm. Within this range, the thermoplastic resin composition may have good properties in terms of impact resistance and appearance.

In some embodiments, the diene rubber polymer may be present in an amount of about 20 wt% to about 65 wt%, for example about 30 wt% to about 60 wt%, based on the total weight of the rubber-modified vinyl graft copolymer, and the monomer mixture (including the aromatic vinyl monomer and the vinyl cyanide monomer) may be present in an amount of about 35 wt% to about 80 wt%, for example about 40 wt% to about 70 wt%, based on the total weight of the rubber-modified vinyl graft copolymer. Within this range, the thermoplastic resin composition may have good properties in terms of impact resistance and flowability.

In some embodiments, aromatic vinyl monomers may be graft copolymerized to the diene rubber polymer, and examples thereof may include styrene, α -methylstyrene, β -methylstyrene, p-tert-butylstyrene, ethylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, dibromostyrene, and vinylnaphthalene, but are not limited thereto.

In some embodiments, vinyl cyanide monomers may be copolymerized with aromatic vinyl monomers, and examples thereof may include acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, α -chloroacrylonitrile, and fumaronitrile, but are not limited thereto.

In some embodiments, examples of the monomer for imparting processability and heat resistance may include (meth) acrylic acid, maleic anhydride, and N-substituted maleimide, but are not limited thereto. The monomer for imparting processability and heat resistance may be present in an amount of about 15 wt% or less, for example about 0.1 wt% to about 10 wt%, based on the total weight of the monomer mixture. Within this range, the monomer for imparting processability and heat resistance can impart processability and heat resistance to the thermoplastic resin composition without deteriorating other properties.

In some embodiments, the rubber-modified vinyl graft copolymer may include, for example, acrylonitrile-butadiene-styrene graft copolymer (g-ABS), but is not limited thereto.

In some embodiments, the rubber-modified vinyl graft copolymer may be present in an amount of about 10 wt% to about 70 wt%, such as about 15 wt% to about 65 wt%, about 20 wt% to about 60 wt%, about 20 wt% to about 55 wt%, or about 25 wt% to about 50 wt%, based on the total weight of the base resin ((a) + (B)). Within this range, the thermoplastic resin composition may have good properties in terms of chemical resistance, rigidity, flowability, and a balance therebetween.

(B) A first aromatic vinyl-vinyl cyanide copolymer

The first aromatic vinyl-vinyl cyanide copolymer is used to improve chemical resistance and flowability of the thermoplastic resin composition, and is a polymer including a monomer mixture of an aromatic vinyl monomer and a vinyl cyanide monomer, wherein the polymer may have a weight average molecular weight of about 100,000g/mol to about 500,000g/mol, for example about 200,000g/mol to about 400,000g/mol, and may contain about 25 wt% to about 31 wt% of repeating units derived from the vinyl cyanide monomer. For example, the first aromatic vinyl-vinyl cyanide copolymer may be a copolymer containing a repeating unit derived from an aromatic vinyl monomer and a repeating unit derived from a vinyl cyanide monomer, and may be obtained by polymerizing a monomer mixture via any suitable polymerization method known in the art such that the weight average molecular weight and the repeating unit content of the first aromatic vinyl-vinyl cyanide copolymer fall within the above-described ranges. In addition, the monomer mixture may further include a monomer for imparting processability and heat resistance, as necessary, and thus the first aromatic vinyl-vinyl cyanide copolymer may further contain a repeating unit derived from the monomer for imparting processability and heat resistance.

In some embodiments, the aromatic vinyl monomer may form a repeating unit derived therefrom by polymerization with a vinyl cyanide monomer or the like, and examples thereof may include, but are not limited to, styrene, α -methylstyrene, β -methylstyrene, p-tert-butylstyrene, ethylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, dibromostyrene, and vinylnaphthalene.

In some embodiments, the vinyl cyanide monomer may form a repeating unit derived therefrom by polymerization with an aromatic vinyl monomer or the like, and examples thereof may include acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, α -chloroacrylonitrile, and fumaronitrile, but are not limited thereto.

In some embodiments, examples of the monomer for imparting processability and heat resistance may include (meth) acrylic acid, maleic anhydride, and N-substituted maleimide, but are not limited thereto. When used in the monomer mixture, the monomer for imparting processability and heat resistance may be present in an amount of about 15 wt% or less, for example about 0.1 wt% to about 10 wt%, based on the total weight of the monomer mixture. Within this range, the monomer for imparting processability and heat resistance can impart processability and heat resistance to the thermoplastic resin composition without deteriorating other properties.

In some embodiments, the weight average molecular weight of the first aromatic vinyl-vinyl cyanide copolymer can be from about 100,000g/mol to about 500,000g/mol, for example, from about 200,000g/mol to about 400,000g/mol or from about 250,000g/mol to about 350,000g/mol, as measured by Gel Permeation Chromatography (GPC). If the weight average molecular weight of the first aromatic vinyl-vinyl cyanide copolymer is less than about 100,000g/mol, the thermoplastic resin composition may have poor impact resistance, and if the weight average molecular weight of the first aromatic vinyl-vinyl cyanide copolymer exceeds about 500,000g/mol, the thermoplastic resin composition may have poor flowability.

In some embodiments, the first aromatic vinyl-vinyl cyanide copolymer may be present in an amount of about 30 wt% to about 90 wt%, such as about 35 wt% to about 85 wt%, about 40 wt% to about 80 wt%, about 45 wt% to about 80 wt%, or about 50 wt% to about 75 wt%, based on the total weight of the base resin ((a) + (B)). Within this range, the thermoplastic resin composition may have good properties in terms of chemical resistance, rigidity, impact resistance, flowability, and a balance therebetween.

(C) Second aromatic vinyl-vinyl cyanide copolymer

The second aromatic vinyl-vinyl cyanide copolymer of the present invention is used to impart high temperature tensile strength to a thermoplastic resin.

The second aromatic vinyl-vinyl cyanide copolymer is a copolymer containing a repeating unit derived from an aromatic vinyl monomer and a repeating unit derived from a vinyl cyanide monomer.

The second aromatic vinyl-vinyl cyanide copolymer may be prepared by cross-linking polymerization of a monomer mixture including an aromatic vinyl monomer and a vinyl cyanide monomer.

In some embodiments, the aromatic vinyl monomer may form a repeating unit derived therefrom by polymerization with a vinyl cyanide monomer or the like, and examples thereof may include styrene, α -methylstyrene, β -methylstyrene, p-tert-butylstyrene, ethylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, dibromostyrene, and vinylnaphthalene, but are not limited thereto.

In some embodiments, the second aromatic vinyl-vinyl cyanide copolymer can have a weight average molecular weight of about 4,000,000g/mol or greater, for example from about 4,000,000g/mol to about 10,000,000g/mol, as measured by Gel Permeation Chromatography (GPC). If the weight average molecular weight of the second aromatic vinyl-vinyl cyanide copolymer is less than about 4,000,000g/mol, the thermoplastic resin composition may not have a sufficient level of high temperature tensile strength.

In some embodiments, the second aromatic vinyl-vinyl cyanide copolymer may be present in an amount of about 1 part by weight to about 10 parts by weight, for example, about 1 part by weight to about 5 parts by weight, relative to about 100 parts by weight of the base resin ((a) + (B)). Within this range, the thermoplastic resin composition may have good properties in terms of high-temperature tensile strength, chemical resistance, rigidity, impact resistance, flowability, and a balance therebetween.

In some embodiments, the weight ratio of (B) to (C) may range from about 90:1 to about 3:1, for example, from about 75:1 to about 30:1 or from about 40:1 to about 35: 1. Within this range, the thermoplastic resin composition may have good properties in terms of flowability, processability, and high-temperature tensile strength efficiency.

(D) Zinc oxide

The zinc oxide according to the invention can be prepared by: melting metallic zinc in a reactor, heating the molten zinc to about 850 ℃ to about 1,000 ℃ (e.g., about 900 ℃ to about 950 ℃) to vaporize the molten zinc, injecting oxygen into the reactor, cooling the reactor to about 20 ℃ to about 30 ℃, heating the reactor to about 400 ℃ to about 900 ℃ (e.g., 500 ℃ to about 800 ℃) for about 30 minutes to about 150 minutes while injecting nitrogen/hydrogen into the reactor as needed, and cooling the reactor to room temperature (about 20 ℃ to about 30 ℃).

The zinc oxide prepared as above may have a peak intensity ratio (B/a) in photoluminescence measurement of about 0.01 to about 10, for example about 0.01 to about 2, about 0.01 to about 1, about 0.01 to about 0.5, or about 0.1 to about 0.3, wherein a indicates a peak in a wavelength range of 370nm to 390nm, and B indicates a peak in a wavelength range of 450nm to 600nm, and a BET specific surface area of about 15m²A/g or less, e.g., about 10m²A/g or less, or about 1m²G to about 7m²(ii) in terms of/g. Within this range of the peak intensity ratio (B/a), the thermoplastic resin composition may have good antibacterial properties while having discoloration resistance, low odor, and high-temperature tensile strength. Further, when the BET specific surface area is about 15m²The thermoplastic resin composition may have a low odor per gram or less.

In some embodiments, the zinc oxide can have various shapes, for example, a spherical shape, a plate shape, a rod shape, and combinations thereof.

The zinc oxide may have an average particle size of from about 0.5 μm to about 3 μm, for example from about 1 μm to about 3 μm, as measured in a single particle state (without forming secondary particles by agglomeration of the particles) using a particle size analyzer (laser diffraction particle size analyzer LS I3320, Beckman Coulter co., Ltd.). Within this range, the thermoplastic resin composition may exhibit good discoloration resistance and low odor properties.

In X-ray diffraction (XRD) analysis, the peak position (2 θ) of zinc oxide may be in the range of about 35 ° to about 37 ° and the crystallite size may be about 35 ° to about 37 °, as calculated by formula 4

To about

For example about

To about

Or about

To about

Within this range, the thermoplastic resin composition may have good initial odor, weatherability, and antibacterial properties.

[ formula 4]

In some embodiments, the zinc oxide may be present in an amount of about 2 parts by weight to about 10 parts by weight, for example about 1 part by weight to about 5 parts by weight, relative to about 100 parts by weight of the base resin ((a) + (B)). Within this range, the thermoplastic resin composition may have good low odor properties, impact resistance and antibacterial properties.

In addition, the weight ratio of the second aromatic vinyl-vinyl cyanide copolymer (C) to the zinc oxide (D) may be in the range of about 1:0.5 to about 1:5, for example, about 1:1 to about 1: 3. If the weight ratio exceeds about 1:5, the thermoplastic resin composition may exhibit a balance between poor physical properties, and if the weight ratio is less than about 1:0.5, the thermoplastic resin composition may exhibit low antibacterial activity.

The thermoplastic resin composition according to one embodiment of the present invention may further include additives such as flame retardants, antioxidants, lubricants, mold release agents, nucleating agents, antistatic agents, stabilizers, colorants and combinations thereof, without changing the desired effects of the present invention. When used in the thermoplastic resin composition, the additive may be present in an amount of about 20 parts by weight or less, for example, about 0.1 parts by weight to about 10 parts by weight, relative to about 100 parts by weight of the base resin, but is not limited thereto.

[ equation 1]

6kg/cm²≤TS₁₅₀≤20kg/cm²

[ formula 2]

485kg/cm²≤TS₂₃≤600kg/cm²

In addition, the thermoplastic resin composition may have an Izod notched impact strength of about 20 kgf-cm/cm to about 40 kgf-cm/cm as measured at 23 ℃ on an 1/4 ″ thick sample according to ASTM D256, and a low temperature impact strength of about 7 kgf-cm/cm to about 15 kgf-cm/cm as measured at-30 ℃ according to ASTM D256.

[ formula 3]

Log (M1/M2)

In one embodiment, the thermoplastic resin composition may have a total volatile organic compound detection area of from about 200 to about 500 area/g, for example, from about 200 to about 460 area/g, from about 250 to about 450 area/g, or from about 300 to about 400 area/g, as measured by headspace solid phase microextraction (HS-SPME GC/MS) in combination with gas chromatography/mass spectrometry after collecting the volatile organic compounds for 300 minutes at 120 ℃.

In one embodiment, the thermoplastic resin composition can have a residual volatile content of from about 800ppm to about 1,200ppm, for example from about 900ppm to about 1,100ppm or from about 950ppm to about 1,080ppm, as measured by gas chromatography/mass spectrometry (GC/MS) at 250 ℃.

The molded article according to the present invention is formed of the above thermoplastic resin composition. The thermoplastic resin composition according to the present invention may be prepared by any suitable thermoplastic resin composition preparation method known in the art. For example, the thermoplastic resin composition in the form of pellets can be prepared by mixing the above-mentioned components and optional additives, followed by melt-extrusion in an extruder. The prepared pellets can be produced into various molded articles (articles) by various molding methods such as injection molding, extrusion, vacuum forming and casting. Such shaping methods are well known to those skilled in the art. The molded article can be used as interior/exterior materials for electric/electronic products and materials for automobile parts. In particular, the molded article may be manufactured by vacuum forming, and may be used as a material for interior parts of a refrigerator.

[ MEANS FOR THE INVENTION ]

Next, the present invention will be described in more detail with reference to some examples. It should be understood that these examples are provided for illustration only and are not to be construed as limiting the invention in any way.

Examples

The detailed information of the components used in the examples and comparative examples is as follows:

(A) rubber modified vinyl graft copolymers

A g-ABS copolymer obtained by graft copolymerizing 42 wt% of styrene and acrylonitrile (weight ratio: 75/25 (styrene/acrylonitrile)) and 58 wt% of polybutadiene rubber (average particle diameter: 0.3 μm) was used.

(B) A first aromatic vinyl-vinyl cyanide copolymer

A resin (weight average molecular weight: 250,000g/mol) obtained by polymerizing 71 wt% of styrene and 29 wt% of acrylonitrile was used.

(C) Second aromatic vinyl-vinyl cyanide copolymer

(C1) A bead copolymer (ZB-869, Zibo Huaxing Additives Co., Ltd.) comprising 72.5 wt.% of styrene monomer and 27.5 wt.% of acrylonitrile monomer was used. The second aromatic vinyl-vinyl cyanide copolymer had a weight average molecular weight of 5,100,000 g/mol.

(C2) A bead copolymer (ZB-869, Zibo Huaxing Additives Co., Ltd.) comprising 72.5 wt.% of styrene monomer and 27.5 wt.% of acrylonitrile monomer was used. The second aromatic vinyl-vinyl cyanide copolymer had a weight average molecular weight of 3,000,000 g/mol.

(D) Zinc oxide

(D1) Metallic zinc was melted in a reactor, and then heated to 900 ℃ to vaporize the molten zinc, and then oxygen was injected into the reactor, followed by cooling to room temperature (25 ℃) to obtain an intermediate. Then, the intermediate was subjected to heat treatment at 700 ℃ for 30 to 150 minutes, and then cooled to room temperature (25 ℃), thereby preparing zinc oxide (D1). The zinc oxide (D1) had a purity of 99% or more, an average particle diameter (D50) of 1.2 μm, and no halogen (Cl, Br).

(D2) The zinc oxide product (manufacturer: Ristecbiz Co., Ltd., product name: RZ-950) was used.

(D3) Zinc oxide prepared by heat-treating a zinc oxide product (manufacturer: risteccbiz co., ltd., product name: RZ-950) at 700 ℃ for 90 minutes and then cooling to room temperature (25 ℃) was used.

For each of zinc oxides D1, D2, D3, the average particle diameter, BET surface area, purity, peak intensity ratio (B/a) of peak B in a wavelength range of 450nm to 600nm to peak a in a wavelength range of 370nm to 390nm in photoluminescence measurement, and crystallite size were measured by the following methods. The results are shown in Table 1.

TABLE 1

Measurement of the Properties of Zinc oxide

(1) Average particle diameter (unit: μm): the average particle size (volume average) was measured using a particle size analyzer (laser diffraction particle size analyzer LS I3320, Beckman Coulter co., Ltd.).

(2) Purity (unit:%): purity was measured by thermogravimetric analysis (TGA) based on the weight of residual material at 800 ℃.

(3) BET surface area (unit: m)²(iv)/g): BET surface area was measured by nitrogen adsorption using a BET analyzer (surface area and porosity analyzer ASAP 2020, Micromeritics co., Ltd.).

(4) PL Peak intensity ratio (B/A): in the photoluminescence measurement method, a spectrum emitted when a sample was irradiated with a He-Cd laser (KIMMON, 30mW) at a wavelength of 325nm was detected by a CCD detector at room temperature, wherein the CCD detector was maintained at-70 ℃. The peak intensity ratio (B/A) of peak B in the wavelength range of 450 to 600nm to peak A in the wavelength range of 370 to 390nm was measured. Here, in the PL analysis, an injection-molded sample irradiated with a laser beam was not separately processed, and a zinc oxide powder was compressed in a pelletizer having a diameter of 6mm to prepare a flat sample.

(5) Crystallite size (unit:

): the crystallite size was calculated from scherrer equation (equation 4) with reference to the measured FWHM value (full width at half maximum of the diffraction peak) using a high-resolution X-ray diffractometer (PRO-MRD, X' pert Inc.) at a peak position (2 θ) in the range of 35 ° to 37 °. Here, both powder form and injection molded samples can be measured. For more accurate analysis, prior to XRD analysis, the injection-molded sample was subjected to heat treatment in air at 600 ℃ for 2 hours to remove the polymer resin therefrom.

[ formula 4]

Examples 1 to 4 and comparative examples 1 to 4

The above components were mixed in the amounts as listed in Table 2, and then introduced into a twin-screw extruder (L/D: 36, Φ: 45mm), followed by melt-extrusion at 230 ℃ to prepare thermoplastic resin compositions in the form of pellets. The prepared pellets were dried at 80 ℃ for 4 hours or more and then injection-molded using an injection machine (injection temperature: 230 ℃ C., mold temperature: 60 ℃ C.), thereby preparing a sample. The prepared samples were evaluated for the following properties. The results are shown in Table 2.

Evaluation of the Properties of the samples

(1) Impact strength (unit: kgf. cm/cm): izod notched impact strength was measured according to ASTM D256 on 1/4 "thick Izod notched samples.

(2) Tensile Strength (Unit: kg/cm)²)：TS₁₅₀Represents the tensile strength measured according to ASTM D638 on each of the samples prepared in examples and comparative examples at a strain rate of 150mm/min after the samples were left at 150 ℃ for 3 minutes, and TS₂₃Representing the tensile strength measured at 23 ℃ at a strain rate of 5mm/min on each sample according to ASTM D638.

(3) Antibacterial activity: a sample of 5cm X5 cm was inoculated with Staphylococcus aureus and Escherichia coli, respectively, according to JIS Z2801, followed by calculation of antibacterial activity according to formula 3:

[ formula 3]

Log (M1/M2)

Wherein M1 is the number of bacteria measured on a blank sample after 24 hours of incubation at 35 ℃ and 90% RH and M2 is the number of bacteria measured on each sample after 24 hours of incubation at 35 ℃ and 90% RH.

(4) Low odor evaluation by R-SM GC/MS (residual Total volatiles (RTVM), units: ppm): the content of residual total volatiles was measured by gas chromatography/mass spectrometry (GC/MS) at 250 ℃. The measurement conditions and pretreatment methods used were as follows:

-measuring conditions

-pretreatment

1) 0.2g to 0.3g of the sample to be tested is placed in a 20mL vial.

2) 9mL of NMP was added to the vial and dissolved therein with a shaker for 10 hours or more.

3) 1mL of the internal standard solution was added thereto, followed by stirring, and then the resultant material was filtered through a 0.45 μm filter.

(5) Low odor evaluation by HS-SPME GC/MS (Total volatile organic Compounds (TVOC), units: area/g): the area of detection of the volatile organic compounds collected at 120 ℃ for 300 minutes was measured by headspace solid phase microextraction (HS-SPME GC/MS) coupled with gas chromatography/mass spectrometry. The measurement conditions and pretreatment methods used were as follows:

-measuring conditions

-pretreatment

1) The samples were placed in HSS vials (powder: 20mg, pellet: 2g) in that respect

2) The conditions of the headspace sampler were set as above.

(6) Fluidity (vacuum formability):

each of the samples prepared in the form of pellets in examples and comparative examples was dried at 80 ℃ for 4 hours or more and then injection-molded in an injection machine at an injection temperature of 230 ℃ and a mold temperature of 60 ℃ to prepare 6 × 6(15cm × 15cm)2T samples. After the prepared sample was put into a vacuum forming machine (manufacturer: DONGJIN Industry), the vacuum forming machine was set to the following reference conditions: the temperature was 500 ℃, the preheating time was 25 seconds, and the vacuum pressure was 10%. When the sample was bubbled under the reference conditions, water was added to the vacuum forming machine until the bubbling portion of the sample was completely filled with water, and then the volume of the added water was measured to evaluate the fluidity (vacuum formability). When the volume of added water was 1,000ml or more, the corresponding sample was rated as grade 1; when the volume of added water is greater than or equal to 950ml and less than 1,000ml, the corresponding sample is rated as 2; when the volume of added water is greater than or equal to 900ml and less than 950ml, the corresponding sample is rated as 3; and when the volume of added water was less than 900ml, the corresponding sample was rated as 4.

TABLE 2

Lower numbers indicate better flowability.

TABLE 3

Lower numbers indicate better flowability.

It is to be understood that various modifications, alterations, adaptations, and equivalent embodiments may occur to one skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A thermoplastic resin composition, comprising:

(A) rubber-modified vinyl graft copolymers;

(B) a first aromatic vinyl-vinyl cyanide copolymer having a weight average molecular weight of about 100,000g/mol to about 500,000 g/mol;

(C) a second aromatic vinyl-vinyl cyanide copolymer having a weight average molecular weight of about 4,000,000g/mol or more; and

(D) the zinc oxide is added to the mixture of zinc oxide,

wherein the weight ratio of (C) to (D) ranges from about 1:0.5 to about 1: 5.

2. The thermoplastic resin composition of claim 1, comprising:

about 100 parts by weight of a base resin comprising about 10 to about 70 wt% of the rubber-modified vinyl graft copolymer (A) and about 30 to about 90 wt% of the first aromatic vinyl-vinyl cyanide copolymer (B);

about 1 to about 10 parts by weight of the second aromatic vinyl-vinyl cyanide copolymer (C); and

about 2 to about 10 parts by weight of the zinc oxide (D).

3. The thermoplastic resin composition according to claim 1, wherein the rubber-modified vinyl graft copolymer (a) is obtained by graft-copolymerizing a monomer mixture comprising an aromatic vinyl monomer and a vinyl cyanide monomer to a diene rubber polymer.

4. The thermoplastic resin composition of claim 3, wherein said diene rubber polymer has an average particle size of about 0.1 μm to about 0.4 μm.

5. The thermoplastic resin composition of claim 1, wherein said second aromatic vinyl-vinyl cyanide copolymer (C) has a weight average molecular weight of about 4,000,000g/mol to about 10,000,000 g/mol.

6. The thermoplastic resin composition of claim 1, wherein said zinc oxide (D) has a peak intensity ratio (B/a) of about 0.01 to about 10 in photoluminescence measurement, wherein a indicates a peak in a wavelength range of 370nm to 390nm, and B indicates a peak in a wavelength range of 450nm to 600 nm.

7. The thermoplastic resin composition of claim 1, wherein said zinc oxide (D) has a peak intensity ratio (B/a) of about 0.01 to about 1 in photoluminescence measurement, wherein a indicates a peak in a wavelength range of 370nm to 390nm, and B indicates a peak in a wavelength range of 450nm to 600 nm.

8. The method of claim 1A thermoplastic resin composition, wherein said zinc oxide (D) has a BET specific surface area of about 15m²(ii) g or less.

9. The thermoplastic resin composition of claim 1, wherein, in X-ray diffraction (XRD) analysis, the zinc oxide (D) has a peak position (2 θ) in the range of about 35 ° to about 37 ° and a crystallite size of about 35 ° to about 37 ° as calculated from formula 4

To about

10. The thermoplastic resin composition of claim 1, wherein said zinc oxide (D) has an average particle diameter (D50) of about 0.5 μm to about 3 μm.

11. The thermoplastic resin composition of claim 1, wherein the thermoplastic resin composition satisfies formula 1 and formula 2:

[ equation 1]

6kg/cm²≤TS₁₅₀≤20kg/cm²

Wherein TS₁₅₀Represents the tensile strength of the thermoplastic resin composition measured at a strain rate of 150mm/min after leaving the thermoplastic resin composition at 150 ℃ for 3 minutes according to ASTM D638, and

[ formula 2]

485kg/cm²≤TS₂₃≤600kg/cm²

Wherein TS₂₃Denotes a temperature of 5m at 23 ℃ according to ASTM D638Tensile strength of the thermoplastic resin composition measured at a strain rate of m/min.

12. The thermoplastic resin composition of claim 1, wherein said thermoplastic resin composition has an antibacterial activity against staphylococcus aureus of about 2 to about 5 and an antibacterial activity against escherichia coli of about 2 to about 5, as measured according to JIS Z2801 on 5cm x 5cm samples, respectively, inoculated with staphylococcus aureus and escherichia coli, and calculated according to formula 3:

[ formula 3]

Log (M1/M2)

13. The thermoplastic resin composition of claim 1, wherein the thermoplastic resin composition has a total volatile organic compound detected area of about 200 to about 500 area/g as measured by HS-SPME GC/MS after collecting volatile organic compounds at 120 ℃ for 300 minutes.

14. The thermoplastic resin composition of claim 1, wherein the thermoplastic resin composition has a residual volatile content of about 800ppm to about 1,200ppm as measured by GC/MS at 250 ℃.

15. A molded article formed from the thermoplastic resin composition according to any one of claims 1 to 14.

16. The molded article of claim 15, wherein the molded article is formed by vacuum forming and is used for refrigerator interior parts.