Polypropylene resin composition and molded article produced therefrom

Abstract

A polypropylene resin composition of the present invention comprises: about 100 parts by weight of a block polypropylene resin having an isotactic index of about 98.5 wt% or more; about 8 to about 27 parts by weight of a melt blend of about 65 to about 99 wt% of an ultra-low-density polyethylene having a density, measured in accordance with ISO 1183-1, of about 0.88 to about 0.91 g / cm3, and about 1 to about 35 wt% of a styrenic thermoplastic elastomer; about 8 to about 27 parts by weight of a polyolefin elastomer; and about 20 to about 45 parts by weight of talc. The polypropylene resin composition has excellent impact resistance, rigidity, dimensional stability, balance of properties thereof, and the like.

Description

Polypropylene resin composition and molded article manufactured therefrom

[0001] The present invention relates to a polypropylene resin composition and a molded article manufactured therefrom. More specifically, the present invention relates to a polypropylene resin composition having excellent impact resistance, rigidity, dimensional stability, and a balance of these physical properties, and a molded article manufactured therefrom.

[0002]

[0003] Polyolefin resins boast excellent chemical resistance, weather resistance, and processability, making them easy to manufacture into injection-molded products, films, and blow-molded parts. They are widely used in fields such as electrical components, automobiles, and building materials. However, conventional propylene resins have low impact resistance, so olefin elastomers based on copolymers of ethylene and α-olefins are used to enhance impact resistance.

[0004] However, the rubber (olefin elastomer) added during this process may lower the rigidity, etc. of the propylene resin composition, and if inorganic fillers, etc. are added to improve rigidity, etc., impact resistance, etc. may be lowered. In addition, depending on the characteristics of the crystalline polymer, the propylene resin exhibits high shrinkage characteristics, and there is a concern that post-shrinkage may occur even when olefin elastomers and inorganic fillers, etc. are added.

[0005] Therefore, there is a need to develop a polypropylene resin composition with excellent impact resistance, rigidity, dimensional stability, and a balance of these properties.

[0006] The background technology of the present invention is disclosed in Korean Patent No. 10-0842162, etc.

[0007]

[0008] The purpose of the present invention is to provide a polypropylene resin composition having excellent impact resistance, rigidity, dimensional stability, and a balance of these physical properties.

[0009] Another object of the present invention is to provide a molded article formed from the polypropylene resin composition.

[0010] The above and other objects of the present invention can all be achieved by the present invention described below.

[0011]

[0012] 1. One aspect of the present invention relates to a polypropylene resin composition. The polypropylene resin composition comprises about 100 parts by weight of a block polypropylene resin having an isotactic index of about 98.5 wt% or more; and a density of about 0.88 to about 0.91 g / cm as measured according to ISO 1183-1. 3 A composition comprising: about 8 to about 27 parts by weight of a melt blend of about 65 to about 99 weight percent of an ultra-low density polyethylene and about 1 to about 35 weight percent of a styrenic thermoplastic elastomer; about 8 to about 27 weight parts of a polyolefin elastomer; and about 20 to about 45 weight parts of talc.

[0013] 2. In the above 1 specific example, the block polypropylene resin may have a melt-flow index of about 20 to about 40 g / 10 min, measured under conditions of 230°C and 2.16 kg load, according to ASTM D1238.

[0014] 3. In the above 1 or 2 specific examples, the ultra-low density polyethylene may have a melt flow index of about 1 to about 20 g / 10 min, measured under conditions of 230°C and 2.16 kg load, according to ASTM D1238.

[0015] 4. In the above 1 to 3 specific examples, the styrene-based thermoplastic elastomer may include at least one of a styrene-ethylene-butylene-styrene block copolymer, a styrene-ethylene-propylene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, and a styrene-butadiene-butylene-styrene block copolymer.

[0016] 5. In the above specific examples 1 to 4, the styrene-based thermoplastic elastomer may have a content of styrene-based monomer of about 5 to about 50 wt%.

[0017] 6. In the above 1 to 5 specific examples, the styrene-based thermoplastic elastomer may have a weight average molecular weight of about 100,000 to about 450,000 g / mol.

[0018] 7. In the above 1 to 6 specific examples, the polyolefin elastomer may include at least one of ethylene-propylene rubber, ethylene-butene rubber, and ethylene-octene rubber.

[0019] 8. In the above 1 to 7 specific examples, the talc may have an average particle size of about 0.5 to about 3.8 μm as measured by a particle size measuring device.

[0020] 9. In the above 1 to 8 specific examples, the polypropylene resin composition may be in a form in which the block polypropylene resin, the polyolefin elastomer, and the talc are continuous phases, the ultra-low density polyethylene is a dispersed phase, and the styrene-based thermoplastic elastomer is present at the interface of the continuous phase and the dispersed phase.

[0021] 10. In the above 1 to 9 specific examples, the polypropylene resin composition has a Charpy impact strength of about 26.5 to about 45 kJ / m measured according to ISO 180 standard. 2 It could be.

[0022] 11. In the above 1 to 10 specific examples, the polypropylene resin composition may have a flexural modulus of about 1,790 to about 2,200 MPa measured under 2 mm / min conditions according to ISO 178 standards.

[0023] 12. In the above 1 to 11 specific examples, the polypropylene resin composition may have a linear expansion coefficient of about 5 to about 6.7 ㎛ / m·℃ of a 10 mm × 10 mm × 6.4 mm sized specimen measured while heating from -30°C to 30°C at a rate of 5°C / min according to ASTM E831.

[0024] 13. Another aspect of the present invention relates to a molded article. The molded article is characterized in that it is formed from a polypropylene resin composition according to any one of 1 to 12.

[0025]

[0026] The present invention has the effect of providing a polypropylene resin composition having excellent impact resistance, rigidity, dimensional stability, and balance of physical properties thereof, and a molded article formed therefrom.

[0027]

[0028] Hereinafter, the present invention will be described in detail as follows.

[0029] A polypropylene resin composition according to the present invention comprises (A) a block polypropylene resin; (B) a melt blend of ultra-low density polyethylene and a styrenic thermoplastic elastomer; (C) a polyolefin elastomer and (D) talc.

[0030] In this specification, “a to b” indicating a numerical range is defined as “≥a and ≤b”.

[0031]

[0032] (A) Block polypropylene resin

[0033] According to one specific example of the present invention, a block polypropylene resin can be applied together with a melt blend of ultra-low density polyethylene and a styrene-based thermoplastic elastomer, a polyolefin elastomer, and talc, etc., to improve the impact resistance, rigidity, dimensional stability, and physical property balance of the polypropylene resin composition. A block polypropylene resin having an isotactic index of about 98.5 wt% or more can be used.

[0034] In a specific example, the block polypropylene resin may be a block polypropylene resin composed of a homopolypropylene block and an ethylene-propylene copolymer block and / or a homopolyethylene block.

[0035] In a specific example, the block polypropylene resin may have an isotactic index of about 98.5 wt% or more, for example, about 98.5 to about 99.9 wt%. If the isotactic index of the block propylene resin is less than about 98.5 wt%, there is a concern that the rigidity, dimensional stability (low shrinkage characteristics), etc. of the polypropylene resin composition may deteriorate. Here, the isotactic index is expressed as a weight% by measuring the weight of the remaining isotactic component after boiling n-heptane to dissolve the atactic component according to ISO 9113:1986.

[0036] In a specific example, the block polypropylene resin may have a melt flow index (MI) of about 20 to about 40 g / 10 min, for example, about 25 to about 35 g / 10 min, measured under conditions of 230°C and a load of 2.16 kg according to ASTM D1238. Within this range, the mechanical properties, dimensional stability, and balance of these properties of the polypropylene resin composition may be excellent.

[0037]

[0038] (B) Melt blend of ultra-low density polyethylene and styrenic thermoplastic elastomer

[0039] A melt blend of ultra-low density polyethylene and a styrenic thermoplastic elastomer according to one specific example of the present invention can be applied together with a block polypropylene resin, a polyolefin elastomer, and talc, etc., to improve the impact resistance, rigidity, dimensional stability, and physical property balance of the polypropylene resin composition.

[0040] In a specific example, the ultra-low density polyethylene (VLDPE) has a density of about 0.88 to about 0.91 g / cm as measured according to ISO 1183-1. 3 , for example, about 0.885 to about 0.90 g / cm 3 It can be. The density of the above ultra-low density polyethylene is about 0.88 g / cm 3 If it is less than 0.90 g / cm, there is a risk that the appearance characteristics of the polypropylene resin composition (molded product) may deteriorate, and if ... 3 If it exceeds, there is a risk that the impact resistance and rigidity of the polypropylene resin composition may deteriorate.

[0041] In a specific example, the ultra-low density polyethylene may have a melt flow index of about 1 to about 20 g / 10 min, measured under conditions of 190°C and a load of 2.16 kg, according to ASTM D1238. Within this range, the moldability of the polypropylene resin composition may be excellent.

[0042] In a specific example, the ultra-low density polyethylene may have a weight average molecular weight measured by gel permeation chromatography (GPC) of about 100,000 to about 550,000 g / mol, for example, about 150,000 to about 500,000 g / mol. Within this range, the mechanical properties, elasticity, etc. of the polypropylene resin composition may be excellent.

[0043] In a specific example, the ultra-low density polyethylene may be included in an amount of about 65 to about 99 wt%, for example, about 70 to about 95 wt%, based on 100 wt% of the total melt blend. If the amount of the ultra-low density polyethylene is less than about 65 wt%, based on 100 wt% of the total melt blend, there is a concern that the rigidity, dimensional stability, etc. of the polypropylene resin composition may be reduced, and if it exceeds about 99 wt%, there is a concern that the impact resistance, etc. of the polypropylene resin composition may be reduced.

[0044] In specific examples, the styrene-based thermoplastic elastomer may be a styrene-ethylene-butylene-styrene block copolymer, a styrene-ethylene-propylene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a styrene-butadiene-butylene-styrene block copolymer, or a combination thereof.

[0045] In a specific example, the styrenic thermoplastic elastomer may have a styrenic monomer content of about 5 to about 50 wt%, for example, about 5 to about 45 wt%. Within this range, the mechanical properties, elasticity, etc. of the polypropylene resin composition may be excellent.

[0046] In a specific example, the styrene-based thermoplastic elastomer may have a weight average molecular weight measured by gel permeation chromatography (GPC) of about 100,000 to about 450,000 g / mol, for example, about 150,000 to about 400,000 g / mol. Within this range, the mechanical properties, moldability, etc. of the polypropylene resin composition may be excellent.

[0047] In a specific example, the styrenic thermoplastic elastomer may be included in an amount of about 1 to about 35 wt%, for example, about 5 to about 30 wt%, based on 100 wt% of the total molten blend. If the content of the styrenic thermoplastic elastomer is less than 1 wt%, based on 100 wt% of the total molten blend, there is a concern that the impact resistance, etc. of the polypropylene resin composition may be reduced, and if it exceeds 35 wt%, there is a concern that the rigidity, dimensional stability, etc. of the polypropylene resin composition may be reduced.

[0048] In a specific example, the melt blend may be manufactured according to a manufacturing method including the steps of: mixing the ultra-low density polyethylene and the styrenic thermoplastic elastomer to manufacture a mixture; and melt-extruding the mixture.

[0049] In a specific example, the melt extrusion may be performed using a conventional twin-screw extruder at a temperature of about 150 to about 250°C, for example, about 170 to about 230°C. Within this range, the mechanical properties, moldability, and balance of these properties of the polypropylene resin composition may be excellent.

[0050] In a specific example, the molten blend may be manufactured in the form of pellets, and the manufactured pellets may be applied to various thermoplastic resin compositions and molded articles (products), and the molten blend alone may be manufactured into molded articles (products) through various molding methods such as injection molding, extrusion molding, vacuum molding, and casting molding. Such molding methods are well known to those skilled in the art to which the present invention pertains.

[0051] In a specific example, the molten blend may be in the form of a mixture of ultra-low density polyethylene as a continuous phase and a styrenic thermoplastic elastomer as a dispersed phase, and the average particle size of the dispersed phase as measured by a transmission electron microscope may be about 0.1 to about 3 ㎛, for example, about 0.3 to about 1 ㎛.

[0052] In a specific example, the molten blend may be included in an amount of about 8 to about 27 parts by weight, for example, about 8.3 to about 25 parts by weight, based on about 100 parts by weight of the block polypropylene resin. If the content of the molten blend is less than about 8 parts by weight based on about 100 parts by weight of the block polypropylene resin, there is a concern that the impact resistance, dimensional stability, etc. of the polypropylene resin composition may be reduced, and if it exceeds about 27 parts by weight, there is a concern that the rigidity, etc. of the polypropylene resin composition may be reduced.

[0053]

[0054] (C) polyolefin elastomer

[0055] A polyolefin elastomer (POE) according to one specific example of the present invention can be applied together with a melt blend of a block polypropylene resin, an ultra-low density polyethylene, and a styrenic thermoplastic elastomer, and talc, etc., to improve the impact resistance, rigidity, dimensional stability, and physical property balance thereof of a polypropylene resin composition, and a polyolefin elastomer applied to a typical thermoplastic resin composition can be used.

[0056] In specific examples, the polyolefin elastomer may include ethylene-propylene rubber, ethylene-butene rubber, ethylene-octene rubber, combinations thereof, and the like. For example, it may include ethylene-butene rubber, ethylene-octene rubber, and the like.

[0057] In a specific example, the polyolefin elastomer has a density of about 0.85 to about 0.87 g / cm as measured according to ISO 1183-1. 3 , for example, about 0.855 to about 0.865 g / cm 3 It can be. In the above range, the mechanical properties, etc. of the polypropylene resin composition can be excellent.

[0058] In a specific example, the polyolefin elastomer may have a melt flow index of about 0.5 to about 10 g / 10 min, for example, about 1 to about 5 g / 10 min, measured under conditions of 190°C and a load of 2.16 kg according to ASTM D1238. Within this range, the mechanical properties, dimensional stability, and balance of these properties of the polypropylene resin composition may be excellent.

[0059] In a specific example, the polyolefin elastomer may be included in an amount of about 8 to about 27 parts by weight, for example, about 8.3 to about 25 parts by weight, based on about 100 parts by weight of the block polypropylene resin. If the content of the polyolefin elastomer is less than about 8 parts by weight based on about 100 parts by weight of the block polypropylene resin, there is a concern that the impact resistance, dimensional stability, etc. of the polypropylene resin composition may be reduced, and if it exceeds about 27 parts by weight, there is a concern that the rigidity, etc. of the polypropylene resin composition may be reduced.

[0060]

[0061] (D) Talk

[0062] According to one specific example of the present invention, talc can be applied together with a melt blend of a block polypropylene resin, an ultra-low density polyethylene, and a styrenic thermoplastic elastomer, and a polyolefin elastomer, etc., to improve the impact resistance, rigidity, dimensional stability, and physical property balance of the polypropylene resin composition. Talc applied to a typical thermoplastic resin composition can be used.

[0063] In a specific example, the talc is a plate-shaped inorganic filler, and the average particle size measured by a particle size measuring device (Malvern mastersizer 3000) may be about 0.5 to about 3.8 μm, for example, about 1 to about 3.5 μm. Within this range, the mechanical properties, dimensional stability, etc. of the polypropylene resin composition may be excellent.

[0064] In a specific example, the talc may be included in an amount of about 20 to about 45 parts by weight, for example, about 25 to about 40 parts by weight, relative to about 100 parts by weight of the block polypropylene resin. If the amount of the talc is less than about 20 parts by weight relative to about 100 parts by weight of the block polypropylene resin, there is a concern that the rigidity, dimensional stability, etc. of the polypropylene resin composition may be reduced, and if it exceeds about 45 parts by weight, there is a concern that the impact resistance, etc. of the polypropylene resin composition may be reduced.

[0065]

[0066] A polypropylene resin composition according to one specific embodiment of the present invention may further include additives included in conventional thermoplastic resin compositions. Examples of the additives include, but are not limited to, flame retardants, fillers, stabilizers, lubricants, antibacterial agents, release agents, and mixtures thereof. When the additives are used, the content thereof may be about 0.001 to about 40 parts by weight, for example, about 0.1 to about 10 parts by weight, based on about 100 parts by weight of the block polypropylene resin, but is not limited thereto.

[0067]

[0068] A polypropylene resin composition according to one specific example of the present invention may be in the form of pellets obtained by mixing the above components and melt-extruding them at about 180 to about 320°C, for example, about 200 to about 280°C, using a conventional twin-screw extruder.

[0069] In a specific example, the polypropylene resin composition may be in a form in which the block polypropylene resin, the polyolefin elastomer, and the talc are continuous phases, the ultra-low-density polyethylene is a dispersed phase, and the styrenic thermoplastic elastomer is present at the interface of the continuous phase and the dispersed phase. Specifically, the continuous phase may be in a form in which the polyolefin elastomer and talc are each dispersed in the block polypropylene resin, and the dispersed phase (ultra-low-density polyethylene) may be in a form in which the styrenic thermoplastic elastomer at the interface of the continuous phase and the dispersed phase forms a core-shell form (a shell form in which the styrenic thermoplastic elastomer covers at least a portion of the ultra-low-density polyethylene core).

[0070] In a specific example, the core-shell type dispersed phase may have an average particle size of about 0.1 to about 3 μm, for example, about 0.3 to about 1 μm, as measured by transmission electron microscopy (TEM, manufacturer: JEOL, device name: JEM-1400) after a thin-sectioned specimen using a cryomicrotome is stained with 0.5% ruthenium tetroxide. In this range, the mechanical properties of the polypropylene resin composition may be excellent.

[0071] In a specific example, the polypropylene resin composition has a Charpy impact strength of about 26.5 to about 45 kJ / m measured at room temperature (about 23°C) according to ISO 180 standards. 2 , for example, about 27 to about 35 kJ / m 2 It could be.

[0072] In a specific example, the polypropylene resin composition may have a flexural modulus of about 1,790 to about 2,200 MPa, for example, about 1,800 to about 2,000 MPa, measured under 2 mm / min conditions according to ISO 178 standards.

[0073] In a specific example, the polypropylene resin composition may have a coefficient of linear expansion of about 5 to about 6.7 ㎛ / m·℃, for example, about 5.2 to about 6.5 ㎛ / m·℃, of a 10 mm × 10 mm × 6.4 mm sized specimen measured while heating from -30°C to 30°C at a rate of 5°C / min according to ASTM E831.

[0074]

[0075] The molded article according to the present invention is formed from the polypropylene resin composition. The polypropylene resin composition can be manufactured in the form of pellets, and the manufactured pellets can be manufactured into various molded articles (products) through various molding methods such as injection molding, extrusion molding, vacuum molding, and casting molding. Such molding methods are well known to those skilled in the art to which the present invention pertains.

[0076] In a specific example, the molded product has excellent impact resistance, rigidity, dimensional stability, and balance of these properties, and is useful as an interior / exterior material for automobiles, a housing for home appliances, etc.

[0077]

[0078] Hereinafter, the present invention will be described in more detail through examples; however, these examples are for the purpose of explanation only and should not be construed as limiting the present invention.

[0079]

[0080] Example

[0081] Below, the specifications of each component used in the examples and comparative examples are as follows.

[0082] (A) Block polypropylene resin

[0083] (A1) Block polypropylene resin (B-PP, manufacturer: S-OIL, product name: MQ900, isotactic index: 99.5 wt%, melt-flow index: approximately 30 g / 10 min) was used.

[0084] (A2) Block polypropylene resin (B-PP, manufacturer: S-OIL, product name: MQ100, isotactic index: 97 wt%, melt-flow index: approximately 30 g / 10 min) was used.

[0085] (B) Ultra-low density polyethylene and styrenic thermoplastic elastomers

[0086] (B1) Density is about 0.885 g / cm 3 A melt blend was used, which was melt-extruded at approximately 200°C using a twin-screw extruder, containing 90 wt% of ultra-low density polyethylene and 10 wt% of styrene-ethylene-butylene-styrene block copolymer (manufacturer: Sinopec, trade name: YH-503T).

[0087] (B2) Density is about 0.92 g / cm 3 A melt blend was used, which was melt-extruded at approximately 200°C using a twin-screw extruder, containing 90 wt% of ultra-low density polyethylene and 10 wt% of styrene-ethylene-butylene-styrene block copolymer (manufacturer: Sinopec, trade name: YH-503T).

[0088] (B3) Density is about 0.885 g / cm 3 A melt blend was used, which was melt-extruded at approximately 200°C using a twin-screw extruder, containing 60 wt% of ultra-low density polyethylene and 40 wt% of styrene-ethylene-butylene-styrene block copolymer (manufacturer: Sinopec, trade name: YH-503T).

[0089] (B4) Density is about 0.885 g / cm 3 A melt blend was used, which was melt-extruded at approximately 200°C using a twin-screw extruder, containing 99.5 wt% of ultra-low density polyethylene and 0.5 wt% of styrene-ethylene-butylene-styrene block copolymer (manufacturer: Sinopec, trade name: YH-503T).

[0090] (B5) Density is about 0.885 g / cm 390 wt% of ultra-low density polyethylene and 10 wt% of styrene-ethylene-butylene-styrene block copolymer (manufacturer: Sinopec, trade name: YH-503T) were simply mixed.

[0091] (C) polyolefin elastomer

[0092] Ethylene-butene rubber (EBR, manufacturer: LG Chemical, product name: LC565) was used.

[0093] (D) Talk

[0094] Talc (Manufacturer: KOCH, Product Name: KC-5000, Average Particle Size: Approximately 3.5 ㎛) was used.

[0095]

[0096] Examples 1 to 7 and Comparative Examples 1 to 11

[0097] Each of the above components was added in the amounts shown in Tables 1, 2, and 3 below, and then extruded at about 250°C to produce pellets. The extrusion was performed using a twin-screw extruder with an L / D of 48 and a diameter of 75 mm. The manufactured pellets were dried at about 80°C for about 2 hours or more, and then injected into a 110-ton injection molding machine (molding temperature: about 210°C, mold temperature: about 50°C) to produce test pieces. The physical properties of the manufactured test pieces were evaluated using the following methods, and the results are shown in Tables 1, 2, and 3 below.

[0098]

[0099] Method of measuring physical properties

[0100] (1) Charpy impact strength (unit: kJ / m) 2 ): Charpy impact strength was measured at room temperature (approximately 23°C) according to ISO 180 standards.

[0101] (2) Flexural modulus (unit: kgf / cm) 2 ): According to ISO 178 standard, the flexural modulus of 4 mm thick specimens was measured under 2 mm / min conditions.

[0102] (3) Coefficient of linear expansion (unit: ㎛ / m·℃): According to ASTM E831 standard, the temperature was increased from -30℃ to 30℃ at a rate of 5℃ / min, and the coefficient of linear expansion of a specimen measuring 10 mm × 10 mm × 6.4 mm was measured.

[0103]

[0104] Example 1234567 (A) (parts by weight) (A1) 100 100 100 100 100 100 100 (A2) ------- (B) (parts by weight) (B1) 16.725 16.716.716.725 8.3 (B2) ------- (B3) ------- (B4) ------- (B5) ------- (C) (parts by weight) 16.716.725 16.716.7 8.325 (D) (parts by weight) 33.333.333.325 40 33.333.3 Charpy Impact strength 28.0 30.0 31.0 30.5 27.0 27.0 30.0 Flexural modulus 1,900 1,800 1,800 1,800 1,950 1,900 1,900 Coefficient of linear expansion 6.0 5.5 5.7 6.5 5.8 6.15.8

[0105]

[0106] Comparative Example 123456 (A) (parts by weight) (A1) - 100 100 100 100 100 (A2) 100 --- (B) (parts by weight) (B1) 16.7 530 --- (B2) --- 16.7 -- (B3) ---- 16.7 -- (B4) ----- 16.7 (B5) ------ (C) (parts by weight) 16.7 16.7 16.7 16.7 16.7 16.7 (D) (parts by weight) 33.3 333.3 333.3 333.3 333.3 Charpy Impact strength 30.0 18.0 33.0 25.0 30.0 25.0 Flexural modulus 1,700 2,000 1,600 1,750 1,750 1,980 Coefficient of linear expansion 8.0 7.1 5.3 6.5 7.0 5.8

[0107]

[0108] Comparative Example 7891011(A) (parts by weight)(A1)100100100100100(A2)-----(B) (parts by weight)(B1)-16.716.716.716.7(B2)-----(B3)-----(B4)-----(B5)16.7----(C) (parts by weight)16.753016.716.7(D) (parts by weight)33.333.333.31050Charpy impact strength25.016.534.033.024.5Flexural modulus1,7502,0001,5801,6502,050Coefficient of linear expansion7.07.05.27.05.5

[0109]

[0110] From the above results, it can be seen that the polypropylene resin composition of the present invention has excellent impact resistance (Charpy impact strength), rigidity (flexural modulus), dimensional stability (linear expansion coefficient), and a balance of these physical properties.

[0111] On the other hand, in Comparative Example 1, where a polypropylene resin (A2) having an isotactic index below the range of the present invention was applied instead of the block polypropylene resin of the present invention, it can be seen that rigidity, dimensional stability, etc. are deteriorated, and in Comparative Example 2, where the content of the melt blend of ultra-low density polyethylene and styrenic thermoplastic elastomer is below the range of the present invention, it can be seen that impact resistance, dimensional stability, etc. are deteriorated, and in Comparative Example 3, where the content of the melt blend of ultra-low density polyethylene and styrenic thermoplastic elastomer exceeds the range of the present invention, it can be seen that rigidity, etc. are deteriorated. In the case of Comparative Example 4, which applied a melt blend (B2) using ultra-low density polyethylene having a density exceeding the range of the present invention instead of the melt blend of the present invention, it was confirmed that impact resistance, rigidity, etc. were deteriorated, and when a melt blend using ultra-low density polyethylene or polyolefin elastomer having a density below the range of the present invention was applied, the appearance characteristics of the injection-molded product (molded article) were deteriorated, and it was confirmed that the melt blend was not suitable for the use of the present invention, and in the case of Comparative Example 5, which applied a melt blend (B3) having an ultra-low density polyethylene content below the range of the present invention, it was confirmed that rigidity, dimensional stability, etc. were deteriorated, and in the case of Comparative Example 6, which applied a melt blend (B4) having an ultra-low density polyethylene content exceeding the range of the present invention, it was confirmed that impact resistance, etc. were deteriorated, and in the case of Comparative Example 7, which applied (B5), which is a simple mixture of ultra-low density polyethylene and a styrene-based thermoplastic elastomer, impact resistance, rigidity, dimensional stability, etc. You can see that it has deteriorated.In addition, in the case of Comparative Example 8, where the content of polyolefin elastomer is less than the range of the present invention, it can be seen that impact resistance, dimensional stability, etc. are reduced, and in the case of Comparative Example 9, where the content of polyolefin elastomer is more than the range of the present invention, it can be seen that rigidity, etc. are reduced, and in the case of Comparative Example 10, where the content of talc is less than the range of the present invention, it can be seen that rigidity, dimensional stability, etc. are reduced, and in the case of Comparative Example 11, where the content of talc is more than the range of the present invention, it can be seen that impact resistance, etc. are reduced.

[0112]

[0113] The present invention has been described with reference to exemplary embodiments. Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from its essential characteristics. Therefore, the disclosed embodiments should be considered illustrative rather than limiting. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. About 100 parts by weight of a block polypropylene resin having an isotactic index of about 98.5 wt% or more; A density of about 0.88 to about 0.91 g / cm as measured according to ISO 1183-1. 3 About 8 to about 27 parts by weight of a melt blend of about 65 to about 99 wt % of an ultra-low density polyethylene and about 1 to about 35 wt % of a styrenic thermoplastic elastomer; About 8 to about 27 parts by weight of a polyolefin elastomer; and A polypropylene resin composition characterized by comprising about 20 to about 45 parts by weight of talc.

2. In the first paragraph, the block polypropylene resin is a polypropylene resin composition characterized in that the melt-flow index measured under conditions of 230° C. and 2.16 kg load according to ASTM D1238 is about 20 to about 40 g / 10 min.

3. A polypropylene resin composition according to claim 1 or 2, wherein the ultra-low density polyethylene has a melt flow index of about 1 to about 20 g / 10 min as measured under conditions of 230° C. and 2.16 kg load according to ASTM D1238.

4. A polypropylene resin composition according to any one of claims 1 to 3, wherein the styrene-based thermoplastic elastomer comprises at least one of a styrene-ethylene-butylene-styrene block copolymer, a styrene-ethylene-propylene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, and a styrene-butadiene-butylene-styrene block copolymer.

5. A polypropylene resin composition according to any one of claims 1 to 4, wherein the styrene-based thermoplastic elastomer has a content of a styrene-based monomer of about 5 to about 50 wt%.

6. A polypropylene resin composition according to any one of claims 1 to 5, wherein the styrene-based thermoplastic elastomer has a weight average molecular weight of about 100,000 to about 450,000 g / mol.

7. A polypropylene resin composition according to any one of claims 1 to 6, characterized in that the polyolefin elastomer comprises at least one of ethylene-propylene rubber, ethylene-butene rubber, and ethylene-octene rubber.

8. A polypropylene resin composition according to any one of claims 1 to 7, wherein the talc has an average particle size of about 0.5 to about 3.8 ㎛ as measured by a particle size measuring device.

9. A polypropylene resin composition according to any one of claims 1 to 8, characterized in that the block polypropylene resin, the polyolefin elastomer, and the talc are continuous phases, the ultra-low density polyethylene is a dispersed phase, and the styrene-based thermoplastic elastomer is present at the interface of the continuous phase and the dispersed phase.

10. In any one of claims 1 to 9, the polypropylene resin composition has a Charpy impact strength of about 26.5 to about 45 kJ / m as measured according to ISO 180 standard. 2 A polypropylene resin composition characterized by:

11. A polypropylene resin composition according to any one of claims 1 to 10, characterized in that the polypropylene resin composition has a flexural modulus of about 1,790 to about 2,200 MPa measured under 2 mm / min conditions according to ISO 178 standards.

12. A polypropylene resin composition according to any one of claims 1 to 11, characterized in that the polypropylene resin composition has a coefficient of linear expansion of about 5 to about 6.7 ㎛ / m·℃ of a specimen measuring 10 mm × 10 mm × 6.4 mm when heated from -30°C to 30°C at a rate of 5°C / min according to ASTM E831.

13. A molded product characterized by being formed from a polypropylene resin composition according to any one of claims 1 to 12.