JP2002012718A - Thermoplastic resin composition and its injection molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition which is excellent in stiffness, impact strength, and flowability and gives a molded article excellent in external appearance without flow marks, and to provide the injection molded article obtained therefrom. SOLUTION: The resin composition contains a polypropylene resin in a content in a specified range, an elastomer in a content in a specified range, an inorganic filler in a content in a specified range, and a resin in a content in a specified range, this resin having such characteristics that the melt tension measured under specified conditions is in a specified range; the swelling ratio measured under specified conditions is in a specified range; and the time required until the ratio of a relaxation modulus measured at a specified temperature to a relaxation modulus measured at a specified time becomes a specified value is in a specified range. The injection molded article is obtained from the resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to rigidity, impact strength,
The present invention relates to a thermoplastic resin composition which has excellent fluidity and, when formed into a molded product, has a good appearance, particularly a flow mark, of the molded product. Further, the present invention relates to an injection molded article comprising the thermoplastic resin composition.

[0002]

2. Description of the Related Art Polypropylene resins are widely used for materials requiring rigidity, impact strength and the like. In recent years, polypropylene-based resins have been particularly used for automotive materials, and in particular, ethylene-propylene block copolymers have been used. In addition, ethylene-propylene block copolymers have conventionally been produced by a solvent method, but the production process is simple, and a continuous gas phase method capable of producing an ethylene-propylene block copolymer at low cost. It is being manufactured.

However, in general, an ethylene-propylene block copolymer produced by a gas phase method has a low swelling ratio (SR) because the intrinsic viscosity ([η] _EP ) of the ethylene-propylene copolymer portion is low. Low, the flow mark is insufficient, the appearance of the molded article is poor, and the intrinsic viscosity ([η] _EP ) of the ethylene-propylene copolymer portion of the ethylene-propylene block copolymer produced by the gas phase method However, when the value is too high, there is a problem that bumps occur and the appearance of the molded body is deteriorated.

[0004] As a method of solving the above-mentioned appearance problem, for example, Japanese Patent Application Laid-Open No. 7-286022 discloses a method.
23 ° C. Intrinsic viscosity of n-decane insoluble component is 0.1 to 20 d
1 / g, the intrinsic viscosity of the n-decane-soluble component at 23 ° C. is 5 to 15 dl / g, and a batch-type solvent method capable of forming a molded product without generating irregularities in appearance. The produced propylene-based block copolymer is described. However, as shown in Comparative Example 3 in the publication, an ethylene-propylene block copolymer having a high intrinsic viscosity of a 23 ° C. n-decane-soluble component which is considered to correspond to an ethylene-propylene copolymer part is In addition, the number of rubber lumps that caused dust was large.

Japanese Patent Application Laid-Open No. 7-286075 discloses that a propylene polymer produced by a continuous method is used at 23 ° C.
A propylene polymer composition comprising an ethylene-propylene block copolymer having an intrinsic viscosity of a decane-soluble component of from 5 to 12 dl / g and capable of forming a molded article without generating bumps in appearance is provided. It has been disclosed. However, the content of the ethylene-propylene block copolymer was as large as 12% by weight or more.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermoplastic resin composition which is excellent in rigidity, impact strength and fluidity, and which has a good appearance, especially a flow mark, when formed into a molded product. An object of the present invention is to provide an injection-molded article made of the thermoplastic resin composition.

[0007]

Means for Solving the Problems In view of such circumstances, the present inventor has conducted intensive studies, and as a result, has found that the content of the polypropylene resin is within a certain range, the content of the elastomer is within a certain range, and the content is at a certain level. And the melt tension (MT) measured under a specific condition is a specific range, the swelling ratio (SR) measured under a specific condition is a specific range, and a specific temperature. The time required for the ratio of the relaxation elastic modulus measured in the above and the relaxation elastic modulus at a specific time to reach a specific value is a specific range, and the heat is characterized by containing a resin whose content is in a specific range. The present inventors have found that a plastic resin composition and an injection-molded article made of the same can solve the above problems, and have completed the present invention.

That is, according to the present invention, 35 to 85% by weight of a polypropylene resin (A) and 10 to 10% of an elastomer (B)
35% by weight, 2 to 30% by weight of an inorganic filler (C), and
The melt tension (MT) measured at 190 ° C. at a winding speed of 15.7 m / min is 0.1 N or more;
At 0 ° C., an L / D of an orifice of 40, the shear rate 1.2 × 10 ³ sec ^- swelling ratio measured in the ¹ (SR) is not less than 1.8, relaxation elastic measured at 210 ° C. Modulus G (t) and relaxation modulus G for 0.02 seconds
The ratio (G (t) / G (0.02)) of (0.02) is 0.
The thermoplastic resin composition containing 0.1 to less than 5% by weight of the resin (D) which requires 10 seconds or more to reach 01 (however, the above (A), (B), (C) and (D) )
The total amount of the thermoplastic resin composition containing is 100% by weight), and an injection-molded article comprising the above-mentioned thermoplastic resin composition. Hereinafter, the present invention will be described in detail.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene resin (A) used in the present invention is not particularly limited, but is preferably
Polypropylene resin having crystallinity, for example,
Examples thereof include a crystalline propylene homopolymer, a crystalline ethylene-propylene copolymer, and a crystalline propylene-α-olefin copolymer, and these may be used alone or in combination of two or more.

The α-olefin used in the crystalline propylene-α-olefin copolymer is an α-olefin having 4 or more carbon atoms, preferably an α-olefin having 4 to 20 carbon atoms. And more preferably an α-olefin having 4 to 12 carbon atoms. For example,
Butene-1, pentene-1, hexene-1, heptene-
1, octene-1, decene-1 and the like. Examples of the crystalline propylene-α-olefin copolymer include a crystalline propylene-butene-1 copolymer, a crystalline propylene-hexene-1 copolymer, and the like.

The crystalline polypropylene resin is preferably a crystalline propylene homopolymer, a crystalline ethylene-propylene block copolymer, or a mixture thereof, and particularly preferably a crystalline ethylene-propylene block copolymer. It is a combined or a mixture of a crystalline ethylene-propylene block copolymer and a crystalline propylene homopolymer.

The crystalline ethylene-propylene block copolymer used in the present invention includes a propylene homopolymer portion (this is referred to as a first segment) and an ethylene-propylene random copolymer portion (this is referred to as a second segment). .) Is a crystalline ethylene-propylene block copolymer.

The propylene homopolymer portion as the first segment includes a weight average molecular weight (Mw) / gel weight permeation chromatography (GPC) method.
Those having a Q value as a number average molecular weight (Mn) ratio of preferably 3.0 to 5.0 are more preferable, and those having a Q value of 3.5 to 4.5 are more preferable. Further, the isotactic pentad fraction calculated by ¹³ C-NMR is preferably 0.98 or more, more preferably 0.99 or more. In addition, the intrinsic viscosity of the tetralin solution at 135 ° C [η] _P
Is preferably 0.7 to 1.1 dl / g.
Those having 8 to 1.0 dl / g are more preferred.

The ethylene-propylene random copolymer portion as the second segment has an intrinsic viscosity [η] _{EP of a} tetralin solution at 135 ° C. of 1.0 to 8.0 dl /.
g is preferably 1.5 to 7.5 dl / g.
Is more preferable. Further, those having an ethylene content [(C2 ′) _EP ] of 25 to 35% by weight are preferred, and those having an ethylene content of 27 to 33% by weight are more preferred.

The ratio (second segment / first segment ratio) of the ethylene-propylene random copolymer portion (second segment) to the propylene homopolymer portion (first segment) is 8 / 92-35 / 65 is preferred.

The crystalline propylene homopolymer used in the mixture of the crystalline ethylene-propylene block copolymer and the crystalline propylene homopolymer is the first segment of the crystalline ethylene-propylene block copolymer. It has the same physical properties as a certain propylene homopolymer portion, and has a weight average molecular weight (Mw) / gel weight permeation chromatography (GPC) method /
Those having a Q value as a number average molecular weight (Mn) ratio of preferably 3.0 to 5.0 are more preferable, and those having a Q value of 3.5 to 4.5 are more preferable. Further, the isotactic pentad fraction calculated by ¹³ C-NMR is preferably 0.98 or more, more preferably 0.99 or more.
Further, the intrinsic viscosity [η] _P of the 135 ° C. tetralin solution is preferably 0.7 to 1.1 dl / g,
More preferably, it is from 1.0 dl / g to 1.0 dl / g.

The method for producing the polypropylene resin used in the present invention is not particularly limited, and known stereoregular olefin polymerization catalysts, for example, known catalysts such as Ziegler-Natta catalyst system, metallocene catalyst system, Using a catalyst system or the like in which they are combined, a known polymerization method such as a bulk polymerization method, a solution polymerization method, a slurry polymerization method or a gas phase polymerization method, or any combination of these polymerization methods can be used. However, a continuous gas phase polymerization method is preferred. In particular, the crystalline ethylene-propylene block copolymer is obtained by homopolymerizing propylene in the presence of a stereoregular olefin polymerization catalyst in the first step of obtaining a crystalline propylene homopolymer portion as the first segment, Those produced by copolymerizing ethylene and propylene in the second step of obtaining a 2-segment ethylene-propylene random copolymer portion are preferred.

The mixing ratio of the polypropylene resin (A) used in the present invention is 35 to 85% by weight, preferably 40 to 80% by weight, and more preferably 45 to 80% by weight.
~ 75% by weight.

When the blending ratio of the polypropylene resin (A) used in the present invention is less than 35% by weight, the rigidity may decrease, and when it exceeds 85% by weight, the impact strength may decrease. .

The elastomer (B) used in the present invention is not particularly limited, but preferably contains a rubber component. For example, an elastomer composed of a rubber containing a vinyl aromatic compound and / or an ethylene-α-olefin random copolymer rubber may be used.

The rubber containing a vinyl aromatic compound of the present invention includes, for example, a block copolymer composed of a vinyl aromatic compound polymer block and a conjugated diene polymer block. Is preferably 80% or more hydrogenated, and more preferably 85% or more hydrogenated. G
Preferably, the molecular weight distribution (Q value) by PC (gel permeation chromatography) method is 2.5 or less, more preferably 2.3 or less. The average content of the vinyl aromatic compound in the rubber containing the vinyl aromatic compound is preferably 10 to 20% by weight, more preferably 12 to 19% by weight.
Further, the melt flow rate (MFR, JIS-K-6758, 230 ° C.) of the rubber containing a vinyl aromatic compound is 1 to 1.
It is preferably 15 g / 10 min, more preferably 2 to 13 g / 10 min.

Examples of the above-mentioned rubber containing a vinyl aromatic compound include styrene-ethylene-butene-styrene rubber (SEBS) and styrene-ethylene-propylene-
Block copolymers such as styrene rubber (SEPS), styrene-butadiene rubber (SBR), styrene-butadiene-styrene rubber (SBS), and styrene-isoprene-styrene rubber (SIS), or water-soluble rubber components And the like.
Further, ethylene-propylene-non-conjugated diene rubber (E
A rubber obtained by reacting an olefin copolymer rubber such as PDM) with a vinyl aromatic compound such as styrene can also be suitably used. Further, two or more kinds of rubbers containing a vinyl aromatic compound may be used in combination.

The method for producing the above-mentioned rubber containing a vinyl aromatic compound is not particularly limited. For example, an olefin-based copolymer rubber or a conjugated diene rubber may be used.
Examples include a method of bonding a vinyl aromatic compound by polymerization, reaction, and the like.

The ethylene-α-olefin random copolymer rubber of the present invention is a random copolymer rubber composed of ethylene and α-olefin, and is not particularly limited as long as it is such a rubber. The α-olefin is an α-olefin having 3 or more carbon atoms, and examples thereof include propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, and decene. , Butene-1, hexene-1, and octene-1.

The ethylene-α-olefin random copolymer rubber includes ethylene-propylene random copolymer rubber, ethylene-butene-1 random copolymer rubber,
Ethylene-hexene-1 random copolymer rubber, ethylene-octene-1 random copolymer rubber, and the like,
Preferably, ethylene-octene-1 random copolymer rubber, ethylene-butene-1 random copolymer rubber or ethylene-propylene random copolymer rubber is used. Further, two or more kinds of ethylene-α-olefin random copolymer rubbers may be used in combination.

The ethylene-octene used in the present invention
(1) The Q value (molecular weight distribution) of the random copolymer rubber according to the GPC method is preferably 2.5 or less, more preferably 2.3 or less. Further, the content of octene-1 in the ethylene-octene-1 random copolymer rubber is preferably from 15 to 45% by weight, more preferably from 18 to 42% by weight. The ethylene-octene-1 random copolymer rubber preferably has a melt flow rate (MFR, JIS-K-6758, 190 ° C.) of 1 to 15 g / 10 min, more preferably 2 to 13 g / 10 min. Minutes.

Ethylene-butene-1 used in the present invention
It is preferable that the Q value (molecular weight distribution) of the random copolymer rubber determined by the GPC method is 2.7 or less, more preferably 2.5 or less. The content of butene-1 in the ethylene-butene-1 random copolymer rubber is 1
The content is preferably 5 to 35% by weight, more preferably 17 to 33% by weight. The ethylene-butene-1 random copolymer rubber has a melt flow rate (MFR, JIS-K-6758, 190 ° C) of 1 to 1.
It is preferably 5 g / 10 min, more preferably 2 to 13 g / 10 min.

The ethylene-propylene random copolymer rubber used in the present invention preferably has a Q value (molecular weight distribution) of 2.7 or less, more preferably 2.5 or less, according to the GPC method. The propylene content in the ethylene-propylene random copolymer rubber is 2%.
The content is preferably 0 to 30% by weight, and more preferably 22 to 28% by weight. The ethylene-propylene random copolymer rubber has a melt flow rate (MFR, JIS-K-6758, 190 ° C) of 1 to 1.
It is preferably 5 g / 10 min, more preferably 2 to 13 g / 10 min.

The method for producing the above-mentioned ethylene-α-olefin random copolymer rubber is not particularly limited, and ethylene and various α-olefins are copolymerized by a known polymerization method using a known catalyst. It can be produced by polymerizing. Known catalysts include, for example, a catalyst system comprising a vanadium compound and an organoaluminum compound, a Ziegler-Natta catalyst system or a metallocene catalyst system, and known polymerization methods include a solution polymerization method, a slurry polymerization method, and a high-pressure ionic weight. Synthetic method or gas phase polymerization method is exemplified.

The compounding ratio of the elastomer (B) used in the present invention is from 10 to 35% by weight, preferably from 15 to 35% by weight.
３０30% by weight. When the content of the elastomer (B) is 1
When the amount is less than 0% by weight, the impact strength of the thermoplastic resin composition may decrease.
Heat resistance may decrease.

The inorganic filler (C) that can be used in the present invention is not particularly limited as long as it can improve the rigidity. Examples thereof include calcium carbonate, barium sulfate, mica, Examples include crystalline calcium silicate, talc, and magnesium sulfate fibers. Preferably, it is talc and / or magnesium sulfate fiber.

The talc used in the present invention is not particularly limited, but is preferably crushed hydrous magnesium silicate. The crystal structure of the molecule shows a pyrophyllite-type three-layer structure, and talc is a stack of these structures, and is particularly preferably a flat plate in which the crystal is finely pulverized to a unit layer.

The average particle diameter of talc used in the present invention is preferably 3 μm or less. Here, the average particle diameter of talc is defined as a 50% equivalent particle diameter D obtained from an integral distribution curve of a sieving method measured by suspending in a dispersion medium such as water or alcohol using a centrifugal sedimentation type particle size distribution analyzer. Means ₅₀ .

Talc may be used without treatment, or various silane coupling agents and titanium cups known in the art may be used for the purpose of improving the interfacial adhesion to the polypropylene resin (A) and improving the dispersibility. You may use what processed the surface with a ring agent, a higher fatty acid, a higher fatty acid ester, a higher fatty acid amide, a higher fatty acid salt, or another surfactant.

The magnesium sulfate fiber that can be used in the present invention is not particularly limited, but preferably has an average fiber length of 5 to 50 μm, more preferably 10 to 30 μm. It is. Further, those having an average fiber diameter of 0.3 to 2.0 μm are preferable, and those having an average fiber diameter of 0.5 to 1.0 μm are more preferable.

The proportion of the inorganic filler used in the present invention is 2 to 30% by weight, preferably 5 to 30% by weight.
And more preferably 10 to 30% by weight. If the compounding ratio of the inorganic filler is less than 2% by weight, the rigidity may decrease, and if it exceeds 30% by weight, the impact strength may be insufficient and the appearance may deteriorate. is there.

The resin (D) used in the present invention refers to a swelling ratio (SR) of a polypropylene resin composition.
Is a resin capable of improving the
The melt tension (MT) measured at 90 ° C. at a winding speed of 15.7 m / min is 0.1 N or more, preferably 0.15 N or more. This melt tension (M
When T) is less than 0.1 N, the appearance of the molded article may be insufficient.

Further, at 220 ° C. of the resin (D), the L / D of the orifice was set to 40, and the shear rate was set to 1.2 × 10 ³ sec.
The swelling ratio (SR) measured at c ^-1 was 1.
8 or more, preferably 2.0 or more. When the swelling ratio (SR) is less than 2.0, the appearance of the molded product may be insufficient.

The relaxation modulus G (t) of the resin (D) measured at 210 ° C. and the relaxation modulus G of the resin (D) at a time of 0.02 sec.
The ratio (G (t) / G (0.02)) of (0.02) is 0.
The time required to reach 01 is 10 seconds or more,
Preferably, it is 15 seconds. The relaxation modulus G (t) measured at 210 ° C. and the relaxation modulus G at a time of 0.02 seconds
The ratio (G (t) / G (0.02)) of (0.02) is 0.
When the time required to reach 01 is less than 10 seconds, the appearance of the molded article may be insufficient.

The resin (D) used in the present invention includes:
For example, a polypropylene master batch of a polypropylene block copolymer and / or a polytetrafluoroethylene fiber and the like can be mentioned. The polypropylene block copolymer is preferably an ethylene-propylene block copolymer, more preferably a propylene homopolymer portion and an ethylene-propylene copolymer portion, and the intrinsic viscosity of the ethylene-propylene copolymer portion. [Η] An ethylene-propylene block copolymer having an _{EP of 8} to 15 dl / g and a content of the ethylene-propylene copolymer of 20 to 40% by weight.

The mixing ratio of the resin (D) used in the present invention is 0.1 to less than 5% by weight, preferably 0.5 to 4.5% by weight, and more preferably 1.0 to 4.5% by weight.
４4.5% by weight. The mixing ratio of the resin (D) is 0.1
If the amount is less than 5% by weight, the appearance of the molded article may be insufficient. If the amount is more than 5% by weight, the fluidity may be reduced.

The thermoplastic resin composition described in the present specification comprises:
It can be manufactured using a kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, a hot roll, or the like. The addition and mixing of each component to the kneader may be performed simultaneously or separately, and examples thereof include the following methods, but are not limited thereto. (Method 1) A method of kneading a polypropylene resin (A) and an inorganic filler (C), adding an elastomer (B), and kneading the resin (D). (Method 2) Inorganic filler (C) is kneaded with polypropylene resin (A) at a high concentration in advance to form a master batch, which is separately diluted with polypropylene resin (A), elastomer (B), etc. A method of kneading (D). (Method 3) A method of kneading a polypropylene resin (A) and an elastomer (B), adding an inorganic filler (C), and then kneading (D). (Method 4) The elastomer (B) is kneaded with the polypropylene resin (A) at a high concentration in advance to form a master batch, and the polypropylene resin (A) and the inorganic filler (C) are added thereto. ) Kneading method. (Method 5) The polypropylene-based resin (A) and the inorganic filler (C), and the polypropylene-based resin (A) and the elastomer (B) are kneaded in advance, and after they are finally combined, the resin (D) is mixed. How to knead.

The kneading temperature is usually from 170 to 250 ° C., more preferably from 190 to 230 ° C. The kneading time is usually 1 to 20 minutes, more preferably 3 to 15 minutes.
Minutes.

In addition, in these kneaders, in addition to the components (A) to (D) used in the present invention, antioxidants, ultraviolet absorbers, lubricants, pigments, antistatic agents, copper damage inhibitors, flame retardants, Additives such as a neutralizing agent, a foaming agent, a plasticizer, a nucleating agent, an air bubble inhibitor, a cross-linking agent, and the like may be appropriately blended as long as the objects and effects of the present invention are not impaired.

The thermoplastic resin composition described in the present specification comprises:
It can be molded into an injection molded body by a generally known injection molding method. In particular, it is suitably used as an injection molded article for automobiles such as door trims, pillars, instrumental panels, and bumpers.

[0046]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these examples. The methods for measuring the physical properties of the resin components and the compositions used in the examples and comparative examples are shown below. (1) Melt flow rate (MFR, unit: g / 10
Min) It was measured according to the method specified in JIS-K-6758. Unless otherwise specified, the measurement was performed at a measurement temperature of 230 ° C. and a load of 2.16 kg.

(2) Flexural modulus (FM, unit: kg / c)
m ² ) Measured according to the method specified in JIS-K-7203. Using a test piece having a thickness of 6.4 mm formed by injection molding and a span length of 100 mm, the load speed is 2.0 or 30 mm / min, and the measurement temperature is 23.
Measured in ° C. (3) Izod impact strength (Izod, unit: kg · c
m / cm ² ) Measured according to the method specified in JIS-K-7110. The measurement temperature was measured at 23 ° C. and −30 ° C. using a notched test piece having a thickness of 6.4 mm formed by injection molding and notching after molding.

(4) Heat deformation temperature (HDT, unit: ° C.) Measured according to the method specified in JIS-K-7207. Fiber stress was measured at 18.6 kg / cm ² or 4.6 kg / cm ² . (5) Rockwell hardness (HR) It was measured according to the method specified in JIS-K-7202. The measurement was performed using a test piece having a thickness of 3.0 mm formed by injection molding. The measured values were displayed on an R scale. (6) Embrittlement temperature (BP, unit: ° C.) Measured according to the method specified in JIS-K-7216. 25 × 150 × 2mm formed by injection molding
A predetermined 6.3 × 38 × 2 mm test piece was punched out from the flat plate and measured.

(7) Intrinsic viscosity (unit: dl / g) Using an Ubbelohde viscometer, reduced viscosities were measured at three points of concentrations of 0.1, 0.2 and 0.5 g / dl. Intrinsic viscosity is described in “Polymer Solution, Polymer Experimental Science 11” (198
(2 years published by Kyoritsu Shuppan Co., Ltd.), page 491, that is, the reduced viscosity was plotted against the concentration, and the extrapolation method was used to extrapolate the concentration to zero. The crystalline polypropylene was measured at a temperature of 135 ° C. using tetralin as a solvent. (7-1) Intrinsic viscosity of crystalline ethylene-propylene block copolymer (7-1a) Intrinsic viscosity of propylene homopolymer portion (first segment): [η] _P First of crystalline ethylene-propylene block copolymer The intrinsic viscosity of the propylene homopolymer portion as the segment: [η] _P is the propylene homopolymer taken out of the polymerization tank after the polymerization of the propylene homopolymer in the first step during the production thereof, and the propylene homopolymer weight taken out. It was determined by measuring [η] _{P of the} coalescence.

(7-1b) Intrinsic viscosity of ethylene-propylene random copolymer portion (second segment): [η] _EP- ethylene random copolymer which is the second segment of _EP crystalline ethylene-propylene block copolymer The intrinsic viscosity of the coalesced portion: [η] _EP is the intrinsic viscosity of the propylene homopolymer portion: [η] _P and the intrinsic viscosity of the entire ethylene-propylene block copolymer: [η] _T. The weight ratio of the random copolymer portion to the entire crystalline ethylene-propylene block copolymer: X was determined by calculation from the following equation. [η] _EP = [η] _T / X- (1 / X-1) [η] _P [η] _P : Intrinsic viscosity (dl /
g) [η] _T : intrinsic viscosity of the entire block copolymer (dl / g)

(7-1c) Weight ratio of the ethylene-propylene random copolymer portion to the entire crystalline ethylene-propylene block copolymer: X The crystalline ethylene-propylene block copolymer of the ethylene-propylene random copolymer portion The weight ratio X to the whole was determined by measuring the heat of crystal fusion of the propylene homopolymer portion (first segment) and the entire crystalline ethylene-propylene block copolymer, respectively, and calculating by the following formula. The heat of crystal fusion was determined by suggestive scanning thermal analysis (D
SC). X = 1− (ΔH _f ) _T / (ΔH _f ) _P (ΔH _f ) _T : heat of fusion (cal) of the entire block copolymer
/ G) (ΔH _f ) _P : heat of fusion of propylene homopolymer (c)
al / g)

(8) Ethylene content of the ethylene-propylene random copolymer in the crystalline ethylene-propylene block copolymer: (C ₂ ') _EP Ethylene-propylene random copolymer of the crystalline ethylene-propylene block copolymer Ethylene content of polymer part:
(C ₂ ′) _EP was obtained by measuring the ethylene content (C ₂ ′) _T (% by weight) of the entire crystalline ethylene-propylene block copolymer by an infrared absorption spectrum method, and calculating by using the following equation. (C ₂ ') _EP = (C ₂ ') _T / X (C ₂ ') _T : ethylene content (% by weight) of the whole block copolymer (C ₂ ') _EP : ethylene-propylene random copolymer part Ethylene content (% by weight) X: weight ratio of ethylene-propylene random copolymer part to the whole crystalline ethylene-propylene block copolymer

(9) Isotactic pentad fraction The isotactic pentad fraction is described in A.I. Zamb
Macromolecules, by Elli et al.
6, 925 (1973), i.e., isotactic linkage in pentad units in a polypropylene molecular chain measured using ¹³ C-NMR,
In other words, it is the fraction of propylene monomer units at the center of a chain in which five propylene monomer units are successively meso-bonded. However, regarding the assignment of the NMR absorption peak, Macromolecules,
8, 687 (1975). Specifically, the isotactic pentad fraction was measured as the area fraction of the mmmm peak in all the absorption peaks in the methyl carbon region of the ¹³ C-NMR spectrum. By this method, NATIONAL PHYSICAL LABORATORO
RY NPL standard CRM No. M19-14 Po
The isotactic pentad fraction of lypropylene PP / MWD / 2 was measured to be 0.94.
It was 4.

(10) Molecular weight distribution (Q value) Gel permeation chromatography (GPC)
Was measured under the following conditions. GPC: 150C type manufactured by Waters Column: Shodex 80 MA 2 manufactured by Showa Denko
Sample volume: 300 μl (polymer concentration: 0.2 wt%) Flow rate: 1 ml / min Temperature: 135 ° C. Solvent: o-dichlorobenzene Calibration curve of elution volume and molecular weight using standard polystyrene manufactured by Toyo Soda Co., Ltd. Created. The weight average molecular weight and the number average molecular weight in terms of polystyrene of the sample were determined using a calibration curve, and the Q value, which is a measure of the molecular weight distribution, was determined by calculating the weight average molecular weight / number average molecular weight.

(11) Melt tension (MT, unit:
N) Melt tension tester RE manufactured by Toyo Seiki Seisaku-sho, Ltd.
Using No. 2, the measurement was performed under the following conditions. Measurement temperature: 190 ° C. Winding speed: 15.7 mm / min (12) Swelling ratio (SR) It was measured using Capillograph 1B manufactured by Toyo Seiki Seisakusho under the following conditions. Measurement temperature: 220 ° C. L / D: 40 Shear rate: 1.2 × 10 ³ sec ⁻¹

(13) Relaxation modulus G (t) and time 0.0
Time until the ratio of the relaxation elastic modulus G (0.02) of 2 seconds becomes 0.01 Measured under the following conditions using a mechanical spectrometer RMS-800 manufactured by Rheometrics. Measurement mode: Stress Relaxation Measurement temperature: 210 ° C. Plate shape: 25 mmφ Parallel plate Distance between plates: 1.9 mm Strain amount: 0.2 Strain applied: 0.2

(14) Appearance Appearance was visually observed using a test piece molded by injection molding, and good or bad was judged.

(Production of injection molded article)
Test specimens as injection molded articles for evaluating physical properties of (3), (4), (5), (6) and (14) were prepared according to the following methods. After drying the composition at 120 ° C. for 2 hours using a hot air drier, the molding temperature was 220 ° C., the mold cooling temperature was 50 ° C., and the injection time was 15 s using an IS150EV type injection molding machine manufactured by Toshiba Machine Co., Ltd.
Injection molding was performed at ec for a cooling time of 30 sec to obtain a test piece as an injection molded body.

(Production of thermoplastic resin composition) The thermoplastic resin composition was produced according to the following method. After weighing a predetermined amount of each component and uniformly premixing with a Henschel mixer or a tumbler, the extruding rate is 30 to 50 kg / hr using a twin-screw kneading extruder (TEX44SS 30BW-2V manufactured by Nippon Steel Works). And the screw rotation speed is 350
The composition was produced by kneading and extruding at a rpm under a vent suction. The screw was constructed by arranging a three-row type rotor and a kneading disk at two locations of a kneading zone, that is, a first feed port, a second feed port, and a zone next to each.

Table 1 shows the physical properties of the polypropylene resin (A) used in Examples 1-4 and Comparative Examples 1-6.
Shows the physical properties of the elastomer (B) used in Examples 1 to 4 and Comparative Examples 1 to 6.

Table 3 shows the mixing ratio (% by weight) of each component in the thermoplastic resin compositions of Examples 1 to 4, and Table 4 shows the mixing ratio of each component in the thermoplastic resin compositions of Comparative Examples 1 to 4. (% By weight), and Table 7 shows the mixing ratio (% by weight) of each component in the thermoplastic resin compositions of Comparative Examples 5 and 6.

Table 5 shows the physical properties of the thermoplastic resin compositions of Examples 1 to 4 and the results of the physical properties and appearance of the injection molded articles obtained using the compositions. Table 6 shows the results of Comparative Examples 1 to 4. The physical properties of the thermoplastic resin composition and the results of the physical properties and appearance of the injection molded articles obtained using the composition are shown. Table 8 shows the physical properties of the thermoplastic resin compositions of Comparative Examples 5 and 6, and the compositions thereof. The results of physical properties and appearance of the injection-molded article obtained by using the method are shown.

Examples 1 and 2 and Comparative Examples 1, 2, 5 and 6
The inorganic filler (C) used in Example 1 was talc, and the inorganic filler (C) used in Examples 3 and 4 and Comparative Examples 3 and 4 was used.
Were talc and magnesium sulfate fibers. Also,
The resin (D) used in Examples 1 to 4 and Comparative Example 5 was 19
At 0 ° C, the melt tension (MT) measured at a winding speed of 15.7 m / min was 0.2 N.
Set the orifice L / D to 40 and the shear rate to 1.2 × 1
Swelling ratio (S) measured at 0 ³ sec ^-1
R) is 2.34, the relaxation modulus G (t) measured at 210 ° C. and the relaxation modulus G (0.02) at a time of 0.02 seconds.
The time required for the ratio (G (t) / G (0.02)) to be 0.01 was 36 seconds, which was an ethylene-propylene block copolymer.

The resin (D), ethylene-p
Propylene homopolymer part of propylene block copolymer
Has a molecular weight distribution (Q value) of 4.0 and its intrinsic viscosity
[Η] _PIs 0.91 dl / g and its isotacticity is
The Cook Pent fraction is 0.99, and the
Ethylene-propylene block copolymer
Intrinsic viscosity [η] of renrandom copolymerized part_EPIs 11.5
dl / g, ethylene-propylene block copolymer
Of the ethylene-propylene random copolymerized moiety in the
Its content was 25.1% by weight, its ethylene
The ethylene content in the renrandom copolymerized portion is 2
It was 3.1% by weight.

The resin (D ') used in Comparative Example 6 was 190
The melt tension (MT) measured at a winding speed of 15.7 m / min.
And the orifice L / D is 40 and the shear rate is 1.2.
The swelling ratio (SR) measured at × 10 ³ sec ⁻¹ was 1.54, and the relaxation modulus G (t) measured at 210 ° C. and the relaxation modulus G (0.0) at a time of 0.02 sec.
The time required for the ratio (G (t) / G (0.02)) of 2) to be 0.01 was 0.3 seconds, which was an ethylene-propylene block copolymer.

The resin (D ′) ethylene-
The intrinsic viscosity [η] _P of the propylene homopolymer portion of the propylene block copolymer is 0.94 dl / g, and the intrinsic viscosity [η] of the ethylene-propylene random copolymer portion of the ethylene-propylene block copolymer is [η] _P. ]
_EP is 5.0 dl / g, the content of the ethylene-propylene random copolymer part in the ethylene-propylene block copolymer is 12.0% by weight, and the ethylene content in the ethylene-propylene random copolymer part is 32.0% by weight.

[0067]

[Table 1] BC: ethylene-propylene block copolymer PP: propylene homopolymer P part: propylene homopolymer part of ethylene-propylene block copolymer or whole propylene homopolymer EP part: ethylene of ethylene-propylene block copolymer -Propylene random copolymer portion Content 1: Content of ethylene-propylene random copolymer portion in ethylene-propylene block copolymer Content 2: Ethylene content in ethylene-propylene random copolymer portion mmmm: Isotactic pentad component rate

[0068]

[Table 2] SEBS-1: Rubber containing vinyl aromatic compound EBR-1: Ethylene-butene-1 copolymer rubber EOR-1: Ethylene-octene-1 copolymer rubber

[0069]

[Table 3]

[0070]

[Table 4]

[0071]

[Table 5]

[0072]

[Table 6]

[0073]

[Table 7]

[0074]

[Table 8]

Examples 1 to 4 are thermoplastic resin compositions satisfying the requirements of the present invention, having high fluidity (MFR),
Excellent balance between rigidity (flexural modulus (FM), heat distortion temperature (HDT) and Rockwell hardness (HR)) and impact strength (Izod impact strength (Izod) and embrittlement temperature (BP)) and injection molding It can be seen that the appearance of the body is good.

On the other hand, Comparative Examples 1 to 4 are thermoplastic resin compositions not using the resin (D), which is one of the requirements of the present invention, and the appearance of the injection molded article is poor. I understand.

Comparative Example 5 is a thermoplastic resin composition that does not satisfy the content of the resin (D), which is one of the requirements of the present invention, and the fluidity of the thermoplastic resin composition is insufficient. You can see that.

In Comparative Example 6, the melt tension (MT) of the resin (D), which is a requirement of the present invention, was measured at 190 ° C. at a winding speed of 15.7 m / min.
Set the orifice L / D to 40 and the shear rate to 1.2 × 1
Swelling ratio (S) measured at 0 ³ sec ^-1
R) and the ratio (G (t)) between the relaxation modulus G (t) measured at 210 ° C. and the relaxation modulus G (0.02) at a time of 0.02 seconds.
/G(0.02)) is a thermoplastic resin composition using a resin (D ′) that does not satisfy the time required until the value becomes 0.01, and it can be seen that the appearance of the injection molded article is poor.

[0079]

Industrial Applicability According to the present invention, a thermoplastic resin composition having excellent rigidity, impact strength, and fluidity, and having a good appearance when molded, and injection molding comprising the thermoplastic resin composition A body is provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 101: 00) C08L 101: 00) (72) Inventor Shinichi Kondo 5-1, Anesaki Beach, Ichihara City, Chiba Prefecture Sumitomo 4F071 AA12X AA15X AA20 AA20X AA22X AA75 AA88 AB24 AB30 AE17 AF14 AF23 BA01 BB05 BC07 4J002 BB052 BB121 BB141 BB152 BP012 BP021 BP023 DE236 DG046 DJ046 DJ016

Claims (7)

[Claims] (1) 35-85% by weight of a polypropylene resin (A), 10-35% by weight of an elastomer (B), 2-30% by weight of an inorganic filler (C), and a winding speed of 15 at 190 ° C. The melt tension measured at 0.7 m / min (M
T) is not less 0.1N or more, at 220 ° C., an L / D of an orifice of 40, the shear rate 1.2 × 10 ³ sec ^{- 1}
Ratio (SR) is 1.8 or more, and the ratio (G) of the relaxation modulus G (t) measured at 210 ° C. to the relaxation modulus G (0.02) at a time of 0.02 seconds.
(T) / G (0.02)) A thermoplastic resin composition characterized by containing 0.1 to less than 5% by weight of a resin (D) having a time of 10 sec or more required until it becomes 0.01. (Provided that the total amount of the thermoplastic resin composition containing (A), (B), (C) and (D) is 100% by weight). 2. The content of the polypropylene resin (A) is 4
The thermoplastic resin composition according to claim 1, wherein the content is 0 to 80% by weight. 3. The elastomer (B) is a rubber containing a vinyl aromatic compound and / or an ethylene-α-olefin copolymer rubber, the content of which is 15 to 30% by weight. 2. The thermoplastic resin composition according to 1. 4. The thermoplastic resin composition according to claim 1, wherein the inorganic filler (C) is talc and / or magnesium sulfate fiber, and its content is 5 to 30% by weight. 5. A winding speed of the resin (D) at 190.degree.
Melt tension (MT) measured at 5.7 m / min
Is not less than 0.15 N and at 220 ° C., the orifice L
The swelling ratio (SR) measured at a shear rate of 1.2 × 10 ³ sec ^-1 with a / D of 40 is 2.0 or more, and the relaxation modulus G (t) and time measured at 210 ° C. Ratio of relaxation modulus G (0.02) of 0.02 seconds (G (t)
/G(0.02)) is 0.01 sec or more, and the content thereof is 0.5 to 4.5.
2. The thermoplastic resin composition according to claim 1, wherein the content is by weight. 6. The resin (D) has an intrinsic viscosity [η] _{EP of 8} to 15 dl / g of an ethylene-propylene copolymer portion and a content of the copolymer portion of 20 to 40% by weight. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is an ethylene-propylene block copolymer. 7. An injection-molded article comprising the thermoplastic resin composition according to claim 1.