Polypropylene resin composition having excellent stiffness, impact resistance, and

Abstract

The present invention relates to a polypropylene resin composition having excellent rigidity, impact resistance, and appearance, and a molded article made from the same. A polypropylene resin molded article made by the polypropylene resin composition according to an embodiment of the present invention has an excellent balance of rigidity and impact resistance, and has an excellent appearance by suppressing a defect in the appearance of a fusion pattern, and thus can be effectively used as a component of a household electrical appliance or an article of daily use.

Description

Technical Field

[0001] The present invention relates to a polypropylene resin composition having excellent rigidity, impact resistance and appearance, and a molded product made thereof. Specifically, the present invention relates to a polypropylene resin composition having excellent rigidity and impact resistance and capable of producing a molded product with suppressed weld line appearance, and a molded product made thereof. Background Art

[0002] Polypropylene resin is a general-purpose resin that is widely used as a material for automotive interior and exterior parts, electrical and home appliance parts, construction and industrial materials, films, pipes and wires due to its excellent economy, mechanical properties, formability and chemical resistance.

[0003] There have been many attempts to further expand the application range of polypropylene by improving its rigidity and impact resistance. In particular, as polypropylene for heat-resistant home appliances such as coffee makers, electric irons and air fryers, propylene homopolymer resins have been used in the past for high heat resistance, but considering the situation where consumers accidentally drop the products, a polypropylene resin composition with high impact resistance is needed.

[0004] For this purpose, a propylene block copolymer resin composition in which ethylene-propylene rubber (EPR) is added to a propylene homopolymer is used to improve impact resistance, but the problem is that the weld line is obvious in appearance. The weld line is the part where the front heads of the molten resin in the mold meet during the injection molding process. Not only is the mechanical property of this part weak, but also the visible weld line reduces consumers' desire to buy the product.

[0005] Japanese Patent Application Publication No. 2000-000838 discloses a resin composition with suppressed weld lines, wherein 15 to 30 wt % of a thermoplastic elastomer and 10 to 30 wt % of an inorganic additive are added to 50 to 70 wt % of a propylene resin, and the composition is subjected to a shear rate of 2,432 s. -1 The melt viscosity is 32 Pa·s, and the swelling ratio (SR) ranges from 1.3 to 2.

[0006] However, conventional polypropylene has limited applications because it is molded with polypropylene itself without compounding. Therefore, it is necessary to develop a propylene resin composition having an excellent balance between rigidity and impact resistance and having an excellent appearance due to the suppression of poor weld line appearance.

[0007] [Prior art literature]

[0008] [Patent Literature]

[0009] (Patent Document 1) Japanese Patent Application Publication No. 2000-000838. Summary of the invention

[0010] Technical issues

[0011] The object of the present invention is to provide a polypropylene resin composition having excellent rigidity, impact resistance and appearance.

[0012] Another object of the present invention is to provide a polypropylene resin molded article made from the above polypropylene resin composition, which has an excellent balance between rigidity and impact resistance and has an excellent appearance because weld line appearance defects are suppressed.

[0013] Technical Solution

[0014] To achieve the above object, according to one embodiment of the present invention, the present invention provides a polypropylene resin composition, comprising a propylene-ethylene block copolymer resin obtained by staged polymerization of a propylene homopolymer matrix component (A) and an ethylene-propylene rubber copolymer dispersed phase component (B) in multiple reactors, wherein, when the propylene-ethylene block copolymer is extracted with a xylene solvent at room temperature, the content of the matrix component (A) as a solvent-insoluble matter that cannot be extracted is 94 to 97 weight %, the content of the dispersed phase component (B) as an extracted solvent-soluble matter is 3 to 6 weight %, the melting temperature of the propylene-ethylene block copolymer resin measured by a differential scanning calorimeter (DSC) is above 162° C., and the ethylene content in the propylene-ethylene block copolymer resin measured by a Fourier transform infrared spectrometer (FT-IR) is 0.5 to 1.5 weight %.

[0015] In a specific embodiment of the present invention, the propylene homopolymer matrix component (A) may have a melt index of 5 to 40 g / 10 min when measured at 230° C. under a 2.16 kg load condition.

[0016] In a specific embodiment of the present invention, the ethylene content in the solvent soluble matter measured by Fourier transform infrared spectrometer (FT-IR) may be 15 to 35 wt %, and the intrinsic viscosity of the solvent soluble matter measured by Ubbelohde viscometer may be 2 to 35 wt %.

[0017] In a specific embodiment of the present invention, the weight ratio of the ethylene content to the solvent soluble content in the propylene-ethylene block copolymer resin may be 0.15 to 0.35.

[0018] The propylene-ethylene block copolymer resin may have a melt index of 3 to 30 g / 10 min when measured at 230° C. under a 2.16 kg load condition.

[0019] In a specific embodiment of the present invention, the polypropylene resin composition may further include one or more additives selected from antioxidants, neutralizers, slip agents, anti-blocking agents, reinforcing agents, fillers, weather stabilizers, antistatic agents, lubricants, nucleating agents, flame retardants, pigments and dyes.

[0020] In a specific embodiment of the present invention, the polypropylene resin composition may further comprise 0.05 to 0.3 parts by weight of one or more antioxidants selected from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and tris(2,4-di-tert-butylphenyl)phosphite, based on 100 parts by weight of the composition.

[0021] In a specific embodiment of the present invention, the polypropylene resin composition may further include 0.01 to 0.3 parts by weight of one or more neutralizers selected from hydrotalcite and calcium stearate based on 100 parts by weight of the composition.

[0022] According to another embodiment of the present invention, the present invention provides a polypropylene resin molded product produced by molding the above-mentioned polypropylene resin composition.

[0023] In a specific embodiment of the present invention, the polypropylene resin molded article can be prepared by injection molding the polypropylene resin composition.

[0024] In a specific embodiment of the present invention, the flexural modulus of the polypropylene resin molded article can be 14,000 kgf / cm 2 The Izod impact strength measured at 23° C. can be 3.5 kgf·cm / cm or more.

[0025] In a specific embodiment of the present invention, the polypropylene resin molded product can be a component of a household appliance or a daily necessity.

[0026] In a preferred embodiment of the present invention, the polypropylene resin molded article may be a part of an electric rice cooker, a steam cleaner, an air fryer, a coffee maker or a vacuum cleaner.

[0027] Beneficial Effects

[0028] The polypropylene resin molded article produced by the polypropylene resin composition according to the embodiment of the present invention has an excellent balance between rigidity and impact resistance, and has excellent appearance with poor weld line appearance suppressed, and can be effectively used as a component of household appliances or daily necessities. DETAILED DESCRIPTION

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

[0030] According to one embodiment of the present invention, the present invention provides a polypropylene resin composition, comprising a propylene-ethylene block copolymer resin obtained by staged polymerization of a propylene homopolymer matrix component (A) and an ethylene-propylene rubber copolymer dispersed phase component (B) in multiple reactors, wherein, when the propylene-ethylene block copolymer is extracted with a xylene solvent at room temperature, the content of the matrix component (A) as a solvent-insoluble matter that cannot be extracted is 94 to 97 weight %, the content of the dispersed phase component (B) as an extracted solvent-soluble matter is 3 to 6 weight %, the melting temperature of the propylene-ethylene block copolymer resin measured by a differential scanning calorimeter (DSC) is above 162° C., and the ethylene content in the propylene-ethylene block copolymer resin measured by a Fourier transform infrared spectrometer (FT-IR) is 0.5 to 1.5 weight %.

[0031] The polypropylene resin composition according to an embodiment of the present invention comprises a propylene-ethylene block copolymer resin. Wherein, the propylene-ethylene block copolymer resin comprises a propylene homopolymer matrix component (A) and an ethylene-propylene rubber copolymer dispersed phase component (B). Specifically, the propylene-ethylene block copolymer resin is obtained by segmented polymerization of the propylene homopolymer matrix component (A) and the ethylene-propylene rubber copolymer dispersed phase component (B) in multiple reactors.

[0032] In the polypropylene resin composition according to an embodiment of the present invention, the content of the propylene homopolymer matrix component (A) in the propylene-ethylene block copolymer resin is 94 to 97% by weight, and the content of the ethylene-propylene rubber copolymer dispersed phase component (B) is 3 to 6% by weight. Here, the matrix component (A) is the solvent-insoluble matter that cannot be extracted when the propylene-ethylene block copolymer is extracted with a xylene solvent at room temperature, and the dispersed phase component (B) is the extracted solvent-soluble matter measured when the propylene-ethylene block copolymer is extracted with a xylene solvent at room temperature.

[0033] As described below, the propylene homopolymer matrix component (A) and the ethylene-propylene rubber copolymer dispersed phase component (B) can be obtained by staged polymerization in multiple reactors. First, in at least one reactor, the propylene homopolymer matrix component (A) is obtained by substantially polymerizing the propylene monomer alone. In at least one subsequent reactor, ethylene and propylene are copolymerized in the presence of the propylene homopolymer matrix component (A) to obtain the ethylene-propylene rubber copolymer dispersed phase component (B). As a result, a propylene-ethylene block copolymer resin in which the ethylene-propylene rubber copolymer dispersed phase component (B) is dispersed in the propylene homopolymer matrix component (A) can be obtained. If the content of the matrix component (A) exceeds the above upper limit (that is, the content of the dispersed phase component (B) is lower than the above lower limit), the impact resistance of the molded product may be reduced. If the content of the matrix component (A) is lower than the above lower limit (that is, the content of the dispersed phase component (B) exceeds the above upper limit), the molded product may have a serious poor appearance of weld lines.

[0034] In the polypropylene resin composition according to an embodiment of the present invention, when measured using a differential scanning calorimeter (DSC), the melting temperature of the propylene-ethylene block copolymer resin is 162° C. or higher. Preferably, when measured using a differential scanning calorimeter (DSC), the melting temperature of the propylene-ethylene block copolymer resin may be 163° C. or higher. When the melting temperature satisfies the above range, it can be effectively used in home appliances or daily necessities that require heat resistance.

[0035] In the polypropylene resin composition according to an embodiment of the present invention, when measured using a Fourier transform infrared spectrometer (FT-IR), the ethylene content in the propylene-ethylene block copolymer resin is 0.5 to 1.5 weight %. Preferably, when measured using a Fourier transform infrared spectrometer (FT-IR), the ethylene content in the propylene-ethylene block copolymer resin may be 0.7 to 1.3 weight %. When the ethylene content in the propylene-ethylene block copolymer resin is less than 0.5 weight %, the impact resistance of the molded article may be reduced, and when the ethylene content is greater than 1.5 weight %, the rigidity of the molded article may be reduced.

[0036] In a specific embodiment of the present invention, the melt index of the propylene homopolymer matrix component (A) may be 5 to 40 g / 10 min when measured at 230° C. under a 2.16 kg load condition. Preferably, the melt index of the propylene homopolymer matrix component (A) may be 6 to 30 g / 10 min when measured at 230° C. under a 2.16 kg load condition. When the melt index satisfies the above range, the melt index of the propylene-ethylene block copolymer resin may satisfy the above preferred range.

[0037] In a specific embodiment of the present invention, when measured using a Fourier transform infrared spectrometer (FT-IR), the ethylene content in the solvent solubles may be 15 to 35% by weight. Preferably, the ethylene content in the solvent solubles may be 18 to 32% by weight. When the ethylene content in the solvent solubles exceeds 35% by weight, the size of the ethylene-propylene rubber copolymer dispersed phase component (B) increases and the distance between each other increases. As a result, the room temperature (23°C) impact resistance of the molded article may be reduced, and the gloss characteristics of the molded article may be reduced. When the ethylene content in the solvent solubles is less than 15% by weight, the glass transition temperature (Tg) of the ethylene-propylene rubber (EPR) copolymer dispersed phase component becomes high and may cause the impact resistance of the molded article to decrease.

[0038] In a specific embodiment of the present invention, when measured using an Ubbelohde viscometer, the intrinsic viscosity of the solvent solubles may be 2 to Preferably, the intrinsic viscosity may be 2.5 to When the intrinsic viscosity of the solvent soluble substance is less than When the intrinsic viscosity exceeds When the molded product is exposed to the sun, the surface may have a segmented appearance defect.

[0039] In a specific embodiment of the present invention, the weight ratio of the ethylene content in the propylene-ethylene block copolymer resin to the solvent soluble content may be 0.15 to 0.35. Preferably, the weight ratio of the ethylene content in the propylene-ethylene block copolymer resin to the solvent soluble content may be 0.15 to 0.32. If the weight ratio is less than 0.15, the glass transition temperature (Tg) of the ethylene-propylene rubber (EPR) copolymer dispersed phase component becomes high and may cause the impact resistance of the molded article to decrease. If the weight ratio exceeds 0.35, the size of the ethylene-propylene rubber (EPR) copolymer dispersed phase component increases and the distance between the dispersed phases increases, which may cause the impact resistance of the molded article to decrease.

[0040] In the polypropylene resin composition according to an embodiment of the present invention, the melt index of the propylene-ethylene block copolymer resin may be 3 to 30 g / 10 min when measured at 230° C. under a load condition of 2.16 kg. Preferably, the melt index of the propylene-ethylene block copolymer resin may be 5 to 28 g / 10 min when measured at 230° C. under a load condition of 2.16 kg. If the melt index is less than 3 g / 10 min, the melt fluidity during injection molding is low and injection molding may not be performed normally; if the melt index exceeds 30 g / 10 min, the impact resistance of the molded product may be reduced.

[0041] In the polypropylene resin composition according to the embodiment of the present invention, the method for preparing the propylene-ethylene block copolymer resin is not particularly limited, and the method for preparing the propylene-ethylene block copolymer resin known in the technical field to which the present invention belongs can be used. For example, bulk polymerization, solution polymerization, slurry polymerization, gas phase polymerization, etc. can be used, and intermittent or continuous polymerization can be used.

[0042] Specifically, the preparation of the propylene-ethylene block copolymer resin can be carried out under a commercial process according to a polymerization method known to those skilled in the art, such as the Spherizone preparation process of LyondellBasell, the Hypol preparation process of Mitsui & Co., Ltd., or the Unipol preparation process of Grace.

[0043] The Spherizone process can be a process that can be continuously polymerized by a ring reactor and a gas phase reactor that are called a multizone circulating reactor (multizonecirculating reactor; MZCR) connected in series. Specifically, in the MZCR reactor, propylene homopolymer can be generated by adding propylene alone. In the subsequent gas phase reactor, ethylene-propylene rubber component can be block copolymerized by adding propylene and ethylene to obtain propylene-ethylene block copolymer resin. The melt index of the generated copolymer resin can be controlled by injecting hydrogen in each reactor.

[0044] The Hypol process can be a process capable of continuous polymerization by two bulk reactors or slurry reactors and two gas phase reactors connected in series. Specifically, in the first to third stage reactors, propylene homopolymer can be generated by adding propylene alone. In the subsequent fourth stage reactor, the ethylene-propylene rubber component can be block copolymerized by adding propylene and ethylene to obtain a propylene-ethylene block copolymer resin. The melt index of the generated copolymer resin can be controlled by injecting hydrogen in each reactor.

[0045] The Unipol process can be a process that enables continuous polymerization by connecting two or more gas phase reactors in series. Specifically, in the case of a process consisting of two gas phase reactors in series, propylene can be added alone in the first stage reactor to generate a propylene homopolymer. In the subsequent second stage reactor, the ethylene-propylene rubber component can be block copolymerized by adding propylene and ethylene to obtain a propylene-ethylene block copolymer resin. The melt index of the generated copolymer resin can be controlled by injecting hydrogen in each reactor.

[0046] In the polypropylene resin composition according to the embodiment of the present invention, the propylene-ethylene block copolymer resin can be prepared in the presence of a Ziegler-Natta catalyst.

[0047] For example, a catalyst system composed by selecting and combining the catalysts mentioned in Korean Patent Application Publication Nos. 2006-0038101, 2006-0038102, 2006-0038103, etc., an alkyl aluminum, and a suitable external electron donor may be used.

[0048] Preferably, the propylene-ethylene block copolymer resin may be prepared by using C601 of Grace Company, but is not particularly limited to the catalyst.

[0049] Without departing from the scope of the present invention, the polypropylene resin composition according to the embodiment of the present invention may further include conventional additives. For example, the polypropylene resin composition may further include one or more additives selected from antioxidants, neutralizers, slip agents, antiblocking agents, reinforcing agents, fillers, weathering stabilizers, antistatic agents, lubricants, nucleating agents, flame retardants, pigments and dyes, but is not particularly limited thereto.

[0050] In a specific embodiment of the present invention, the polypropylene resin composition may further include an antioxidant to increase its heat resistance stability. At this time, based on 100 parts by weight of the polypropylene resin composition, the content of the antioxidant may be 0.05 to 0.3 parts by weight, preferably 0.05 to 0.2 parts by weight. If the content of the antioxidant is less than 0.05 parts by weight, it is difficult to ensure long-term heat resistance stability. If the content of the antioxidant exceeds 0.3 parts by weight, not only the heat resistance stability cannot be further improved, but also the economic efficiency of the product is reduced, so it is not preferred.

[0051] The antioxidant may include phenolic antioxidants, phosphite antioxidants, and the like. Specifically, the antioxidant may include one or more substances selected from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and tris(2,4-di-tert-butylphenyl)phosphite, but is not particularly limited thereto.

[0052] In a specific embodiment of the present invention, the polypropylene resin composition may further include a neutralizer to remove the catalyst component remaining in the polypropylene resin composition. At this time, based on 100 parts by weight of the polypropylene resin composition, the content of the neutralizer may be 0.01 to 0.3 parts by weight, preferably 0.05 to 0.2 parts by weight. If the content of the neutralizer is less than 0.01 parts by weight, it is difficult to fully remove the residual catalyst component. If the content of the neutralizer exceeds 0.3 parts by weight, not only the removal effect of the residual catalyst component is not further improved, but also the economic efficiency of the product is reduced, so it is not preferred.

[0053] The neutralizing agent may include one or more substances selected from hydrotalcite and calcium stearate, but is not particularly limited thereto.

[0054] The preparation method of the polypropylene resin composition according to the embodiment of the present invention is not particularly limited, and the blending method known in the technical field to which the present invention belongs can be directly used, or used after being appropriately improved.

[0055] Specifically, for example, the required amounts of the propylene resin and additives described above can be added to a kneader, roll, Banbury mixer or other mixing machine or a single-screw / twin-screw extruder, and then the added raw materials can be blended using these machines to prepare the polypropylene resin composition of the present invention.

[0056] In another embodiment of the present invention, the present invention provides a polypropylene resin molded article, which is produced by molding the polypropylene resin composition of the present invention.

[0057] The method for preparing the molded article by the polypropylene resin composition according to the embodiment of the present invention is not particularly limited, and methods known in the technical field to which the present invention belongs can be used. For example, the polypropylene resin composition according to the embodiment of the present invention can be molded by conventional methods such as injection molding, extrusion molding, cast molding, etc. to prepare the polypropylene resin molded article. Preferably, the polypropylene resin molded article can be prepared by injection molding the polypropylene resin composition.

[0058] In a specific embodiment of the present invention, the flexural modulus of the polypropylene resin molded article can be 14,000 kgf / cm 2 The polypropylene resin molded article has an excellent balance between rigidity and impact resistance.

[0059] Furthermore, the polypropylene resin composition according to the embodiment of the present invention has an excellent appearance since poor weld line appearance is suppressed.

[0060] The polypropylene resin molded article according to the embodiment of the present invention has an excellent balance between rigidity and impact resistance, and has an excellent appearance with poor weld line appearance suppressed, so it can be effectively used as a component of a household appliance or daily necessities. Specifically, the polypropylene resin molded article according to the embodiment of the present invention can be effectively used as a component of an electric rice cooker, a steam cleaner, an air fryer, a coffee pot, or a vacuum cleaner.

[0061] [Example]

[0062] The present invention will be described in more detail below by way of examples and comparative examples. However, the following examples are only used to illustrate the present invention, and the scope of the present invention is not limited thereto.

[0063] Example 1

[0064] As the Ziegler-Natta catalyst, C601 from Grace Company was used.

[0065] The Hypol process is used to prepare propylene homopolymer by adding propylene to the first to third stage reactors in the presence of the above-mentioned Ziegler-Natta catalyst. The generated propylene homopolymer is transferred to the fourth stage reactor, and gas phase polymerization is carried out by adding ethylene and propylene in the presence of the above-mentioned Ziegler-Natta catalyst to prepare propylene-ethylene block copolymer. At this time, the melt index of the polymer generated in each polymerization reactor is adjusted by adjusting the hydrogen content introduced in each reactor. The specific process conditions are shown in Table 1 below.

[0066] Comparative Examples 1 to 3

[0067] The Hypol process was used, and the specific process conditions are shown in Table 1 below.

[0068] Reference example

[0069] The propylene homopolymer of Comparative Example 1 was mixed with BI6200, a commercial product of Hanwha Total Petrochemical Energy, which was a propylene-ethylene block copolymer, at a ratio of 95:5.

[0070] Experimental example

[0071] The basic physical properties of the resin compositions of Examples, Comparative Examples and Reference Examples were measured by the following methods. The results are shown in Table 1.

[0072] 1. Melt index (g / 10min)

[0073] The melt index of the polypropylene resin is measured at 230° C. and under a load of 2.16 kg according to ASTM D1238.

[0074] 2. Content of ethylene-propylene rubber copolymer component (soluble in xylene solvent) (XS; weight %)

[0075] The determination was performed according to ASTM D5492. Specifically, a propylene-ethylene block copolymer resin was dissolved in xylene at a concentration of 1 wt% (at 140°C for 1 hour), and then the weight extracted was measured after 2 hours at room temperature. The obtained weight was expressed as a percentage relative to the weight of the propylene-ethylene block copolymer resin.

[0076] 3. Ethylene content (C2; weight %)

[0077] Determination was performed by FT-IR according to ASTM D3900.

[0078] 4. Intrinsic viscosity of xylene solubles

[0079] The intrinsic viscosity of the xylene solvent-soluble matter obtained in the above "2" was measured by an Ubbelohde viscometer.

[0080] 5. Flexural modulus

[0081] Flexural modulus was measured at 23°C according to ASTM D770.

[0082] 6. Izod impact strength

[0083] The Izod impact strength was measured according to ASTM D256 at 23°C using notched specimens with a thickness of 3.2 mm.

[0084] 7. Weld line

[0085] 1 wt% of a black masterbatch was added to each resin or composition, and the weld line portion of an injection molded sample made through a mold for evaluating weld lines was observed with the naked eye. When evaluating with the naked eye, blind scoring was adopted, and the severity was indicated by numbers from the most severe sample (5) to the least severe sample (1).

[0086] 8. Melting temperature (DSC)

[0087] Using a differential scanning calorimeter (DSC), the sample was melted at 200°C and then cooled to 50°C at a rate of 10°C / min. Next, the peak temperature of the DSC curve obtained when heated to 200°C at a rate of 10°C / min (i.e., second heating) was taken as the melting temperature.

[0088] 9. Dart impact characteristics

[0089] When a weight of 500 g is dropped from a height of about 14 cm onto a 2 mm sheet sample, the fracture shape is observed.

[0090]

Table 1

[0091]

[0092] PP-MI: Melt index of the propylene homopolymer matrix component

[0093] B-C2: Ethylene content in propylene resin or composition

[0094] XS: xylene soluble content

[0095] XS-C2: Ethylene content in xylene solubles

[0096] XS-IV: Intrinsic viscosity of xylene solubles

[0097] As can be seen from Table 1 above, in the case of the polypropylene resin composition of Example 1 within the scope of the present invention, the molded article made therefrom has an excellent balance between rigidity and impact resistance, and the appearance defect caused by weld lines is not obvious.

[0098] In contrast, in the case of the resin composition of Comparative Example 1 containing only a propylene homopolymer, although the flexural modulus, melting temperature and weld line appearance characteristics are good, the Izod impact strength and dart impact characteristics are low. In the case of Comparative Example 2 containing only a propylene-ethylene random copolymer, the flexural modulus, weld line appearance characteristics and melting temperature are low. In the case of Comparative Example 3 in which the content of solvent (xylene) solubles exceeds the range of the present invention, although the impact resistance and melting temperature are good, the weld line appearance characteristics are poor.

[0099] The polypropylene resin composition of Example 1 exhibits physical properties similar to those of the reference example comprising a mixture of a propylene homopolymer and a propylene-ethylene block copolymer, but the composition of the present invention has the advantages of being easy to prepare and having a low possibility of contaminant mixing.

Claims

1. A polypropylene resin composition comprising a propylene-ethylene block copolymer resin obtained by staged polymerization of a propylene homopolymer matrix component (A) and an ethylene-propylene rubber copolymer dispersed phase component (B) in multiple reactors, in, When the propylene-ethylene block copolymer is extracted with xylene solvent at room temperature, the content of the matrix component (A) as the solvent-insoluble matter that cannot be extracted is 94 to 97 weight percent, and the content of the dispersed phase component (B) as the extracted solvent-soluble matter is 3 to 6 weight percent. The melting temperature of the propylene-ethylene block copolymer resin measured by differential scanning calorimetry is 162° C. or higher. The ethylene content of the propylene-ethylene block copolymer resin measured by Fourier transform infrared spectrometer is 0.5 to 1.5% by weight.

2. The polypropylene resin composition according to claim 1, characterized in that The propylene homopolymer matrix component (A) has a melt index of 5 to 40 g / 10 min when measured at 230°C under a 2.16 kg load condition.

3. The polypropylene resin composition according to claim 1, characterized in that The ethylene content of the solvent soluble matter measured by Fourier transform infrared spectrometer is 15 to 35% by weight, and the intrinsic viscosity of the solvent soluble matter measured by Ubbelohde viscometer is 2 to 4 dl.

4. The polypropylene resin composition according to claim 1, characterized in that The weight ratio of the ethylene content in the propylene-ethylene block copolymer resin to the solvent soluble content is 0.15 to 0.

35.

5. The polypropylene resin composition according to claim 1, characterized in that The propylene-ethylene block copolymer resin has a melt index of 3 to 30 g / 10 min when measured at 230° C. under a 2.16 kg load condition.

6. The polypropylene resin composition according to claim 1, characterized in that The invention further comprises one or more additives selected from antioxidants, neutralizers, slip agents, anti-blocking agents, reinforcing agents, fillers, weathering stabilizers, antistatic agents, lubricants, nucleating agents, flame retardants, pigments and dyes.

7. The polypropylene resin composition according to claim 6, characterized in that Based on 100 parts by weight of the composition, 0.05 to 0.3 parts by weight of one or more antioxidants selected from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and tris(2,4-di-tert-butylphenyl)phosphite are further included.

8. The polypropylene resin composition according to claim 6, characterized in that The composition further comprises 0.01 to 0.3 parts by weight of one or more neutralizing agents selected from hydrotalcite and calcium stearate, based on 100 parts by weight of the composition. 9 . A polypropylene resin molded article produced by molding the polypropylene resin composition according to claim 1 .

10. The polypropylene resin molded article according to claim 9, characterized in that It is produced by injection molding a polypropylene resin composition.

11. The polypropylene resin molded article according to claim 9, characterized in that: Flexural modulus is 14,000kgf / cm 2 As described above, the Izod impact strength measured at 23° C. is 3.5 kgf·cm / cm or more.

12. The polypropylene resin molded article according to claim 9, characterized in that It is a component of household appliances or daily necessities.

13. The polypropylene resin molded article according to claim 12, characterized in that: It is a part of a rice cooker, steam cleaner, air fryer, coffee maker or vacuum cleaner.

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