JP3216942B2 - Polypropylene composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene composition having excellent rigidity and heat resistance, as well as excellent impact resistance and toughness.

[0002]

BACKGROUND OF THE INVENTION Crystalline polypropylene is rigid,
Although excellent in heat resistance, surface glossiness, etc., there is a problem that it is inferior in impact resistance.

For this reason, various methods for improving the impact resistance of polypropylene have been conventionally proposed. For example, a method in which a modifier such as polyethylene or a rubber-like substance is mixed with crystalline polypropylene is known. As such a rubber-like substance, amorphous or low-crystalline ethylene / propylene random copolymer (EPR), polyisobutylene, polybutadiene and the like are generally used.

[0004] However, in order to improve the impact resistance by adding a rubber-like substance as described above, it is necessary to make polypropylene contain a large amount of rubber-like substance. However, a polypropylene composition containing a large amount of rubber-like substance is required. Although the impact resistance is improved, there is a problem that rigidity, heat resistance and surface hardness are greatly reduced.

For this reason, a polypropylene composition containing an inorganic filler such as talc for imparting rigidity together with the rubbery substance as described above has been proposed (JP-A-60-58459, JP-A-60-58459). JP-A-60-60154, JP-A-61-233048, JP-A-61-3
6348, JP-A-62-235350, JP-A-63-122751, JP-A-63-1503
No. 43, JP-A-1-149845, JP-A-1-149845
-204947, JP-A-1-271450, etc.).

However, a polypropylene composition containing a large amount of a rubber-like substance has a limit in improving the rigidity by blending an inorganic filler, and is difficult to use for applications requiring high rigidity. There was a problem.

[0007] For this reason, there is a demand for a polypropylene composition which is excellent in rigidity and heat resistance and also excellent in impact resistance and toughness. The present inventor has studied such a polypropylene composition, and in order to obtain a polypropylene composition having excellent rigidity and heat resistance as well as excellent impact resistance, a generally known type of polypropylene is used. Instead of a polymer alloy of
A rubber-like substance (rubber component) is used as a matrix, polypropylene (a crystal component) is used as a dispersed phase, and polypropylene microcrystals have a specific size in the a-axis, b-axis, and c-axis directions, and around the polypropylene microcrystals. It has been found that the rubber component present in the present invention is only required to be a continuous phase having a specific average thickness, and the present invention has been completed.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a composition containing polypropylene as a main component, which is excellent in rigidity, heat resistance, impact resistance, impact resistance and toughness.

[0009]

SUMMARY OF THE INVENTION The polypropylene composition according to the present invention comprises: (A) 87 to 97% by weight of a crystalline homopolypropylene component and 3 to 13% by weight of ethylene / propylene which is a 23 ° C. n-decane soluble component. A propylene block copolymer comprising a polymerized rubber component, and (1) ASTM D12 of the propylene block copolymer.
Melt flow rate (MF
R: 230 ° C., 2.16 kg load) is 10 to 60 g / 10 min, and (2) the 23 ° C. n-decane-soluble component has an intrinsic viscosity [η] of 4 to 4 measured in decalin at 135 ° C. 12 dl / g, containing 30 to 60 mol% of a structural unit derived from ethylene, and (3) the polypropylene component has an MFR of 20 to 80 g / 10
A propylene block copolymer having a pentad isotacticity (I ₅ ) of 0.97 or more, determined by ¹³ C-NMR method, of 0.97 or more;

(B) (1) The structural unit derived from ethylene is 60 to 9
(2) intrinsic viscosity [η] measured in decalin at 135 ° C. is 1.5 to 3.5 dl / g, and (3) glass transition temperature (Tg) is −50 ° C. or less. Is there
Alternatively, an ethylene / α-olefin random copolymer 1 whose melting point measured as a main peak by the DSC method is 90 ° C. or less, and (4) crystallinity measured by the X-ray diffraction method is less than 20%
5 to 25% by weight,

(C) 5-15% by weight of an inorganic filler, characterized by satisfying the following conditions. (i) a melt flow rate (MFR: 230 ° C., 2.16 kg load) measured according to ASTM D1238 is 10 g / 10 min or more; (ii) a flexural modulus measured according to ASTM D790 and the (FM) is 20,000 kg / cm ² or more, or (iii) the Izod impact strength as measured according to ASTM D256 (IZ) is 20 kg · cm / cm or more, conforming to (iv) ASTM D648 (V) a heat distortion temperature (HDT) of at least 135 ° C. measured in the injection-molded product of the polypropylene composition, and (v) a fine crystal of polypropylene measured by a wide-angle X-ray diffraction method and a small-angle X-ray scattering method. The size is from 5 nm in the c-axis direction
20 nm, 5 nm to 20 nm in a-axis direction, 5 nm in b-axis direction
nm or more, and (vi) in an injection molded article of the polypropylene composition, the rubber component exists as a continuous phase around the polypropylene microcrystals in the injection direction and a direction perpendicular to the injection direction. And the rubber continuous phase has an average thickness of 0.5 nm to 3 nm.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the polypropylene composition according to the present invention will be described specifically. The polypropylene composition according to the present invention contains a polypropylene (crystal component) and a rubber component, and satisfies the following conditions.

(I) Melt flow rate measured according to ASTM D1238 (MFR: 230 ° C., 2.1
Under 6 kg load) is 10 g / 10 min or more, preferably 10
50 g / 10 min.

(Ii) The flexural modulus (FM) measured according to ASTM D790 is 20,000 kg / cm ² or more, preferably 20,000 to 25,000 kg / cm ² . (iii) The Izod impact strength (IZ) measured according to ASTM D256 is 20 kg · cm / cm or more, preferably 25-60 kg · cm / cm, more preferably 30-6.
It is 0 kg · cm / cm.

(Iv) The heat distortion temperature (HD) measured under a load of 4.6 kg / cm ² in accordance with ASTM D648.
T) is 135 ° C. or higher. The polypropylene composition according to the present invention contains polypropylene and a rubber component. In an injection-molded product formed from this polypropylene composition, the rubber component (matrix) contains polypropylene in the a-axis direction and the b-axis direction. And a structure dispersed as fine crystals having a specific size in the c-axis direction. The injection molded article formed from such a polypropylene composition is analyzed by an X-ray diffraction method, a small-angle X-ray scattering method and an electron microscope as described later. Have.

(V) The fine crystals of polypropylene obtained by the X-ray diffraction method and the X-ray small angle scattering method are 5 nm to 20 nm in the c-axis direction, 5 nm to 20 nm in the a-axis direction, and 5 nm or more in the b-axis direction. Has a size of 5 nm to 100 nm, more preferably 5 nm to 30 nm.

(Vi) In this injection-molded product, the rubber component exists as a continuous phase around the polypropylene microcrystals in the injection direction and a direction perpendicular to the injection direction, and the rubber has a continuous phase. Average thickness is 0.5n
m to 3 nm.

In the injection molded article formed from the polypropylene composition according to the present invention, the polypropylene microcrystal and the rubber component have a specific structure as described above, and are excellent in rigidity and heat resistance as well as in heat resistance. Excellent impact and toughness.

Incidentally, injection molded articles formed from a conventionally known polypropylene composition containing a polypropylene and an ethylene / propylene random copolymer have the characteristics specified in the present invention. The rubber component has a structure in which a part of the crystal component is mixed with the rubber component, whereby the rubber component is restricted by the amorphous component of the polypropylene. With such a polypropylene composition, the effect of improving the impact resistance is not sufficient. As described above, conventionally, in order to improve the impact resistance, a large amount of a rubber component (ethylene-propylene random copolymer) is contained in the polypropylene composition. Etc.).

In the present invention, the size of the microcrystals of polypropylene as described above is measured by the following X-ray diffraction method (measured using an RU-200A type X-ray diffractometer manufactured by Rigaku Corporation). can do. In the following, the X-ray wavelength is calculated at 1.5418 °.

Measurement of the size of polypropylene microcrystal The crystal size of the polypropylene microcrystal in the b-axis direction and the a-axis direction is obtained from the wide-angle X-ray diffraction intensity.

The size of the polypropylene microcrystal is calculated from the half width of the peak based on the (040) plane and the (110) plane of the polypropylene crystal using Scherrer's formula. (1) The crystal size in the b-axis direction is obtained from the half width of the (040) plane.

(2) The crystal size in the a-axis direction is (11
0) The value calculated using the Scherrer's formula from the half width of the plane was multiplied by the ratio of the diagonal length of the ab plane of the unit cell of 21.99 ° to the b-axis length of 20.96 °. Calculated as a value.

(3) The crystal size in the c-axis direction is determined by the crystallinity (X%) measured by the X-ray diffraction method and the long period (Å) of the homopolypropylene measured by the small-angle X-ray scattering intensity. (Long cycle Å × X%).

The long period of the homopolypropylene is calculated by measuring the small-angle X-ray scattering intensity of the homopolypropylene and calculating the peak scattering angle according to Bragg's equation. Measurement of the thickness of the rubber phase The thickness of the rubber phase is determined from the scattering angle showing the peak of the small-angle X-ray scattering intensity as the difference between the following two long periods measured according to the Bragg equation.

Long period measured for a composition comprising a propylene block copolymer, an ethylene / α-olefin random copolymer and an inorganic filler. Homopolypropylene (MF of this homopolypropylene
A composition comprising an R value equal to the MFR value of the polypropylene component of the propylene block copolymer in the above composition) and an inorganic filler (the type and amount of the inorganic filler are the same as the above composition) Long period measured for.

Determination of rubber continuous phase When a sample section is stained with ruthenic acid, the rubber component is stained. When this is observed with an electron microscope of 150,000 times,
Crystal (undyed area)-Rubber (dyed area)-Crystal (undyed area)
Is seen repeatedly. From this photograph, it can be determined whether or not it is a rubber continuous phase.

Next, an example of the polypropylene composition according to the present invention which satisfies the above specific conditions will be described below. Although the composition of the polypropylene composition according to the present invention as described above is not limited, for example, (A) a propylene block copolymer as described below,
(B) an ethylene / α-olefin random copolymer;
(C) Fine powder talc.

Each of such components will be specifically described. (A) In the propylene block copolymer the present invention, a polypropylene, a specific propylene block copolymer preferably used. This (A)
The propylene block copolymer is preferably composed of a highly crystalline homopolypropylene component and an ethylene-propylene copolymer rubber component which is a n-decane soluble component at normal temperature (23 ° C.), and satisfies the following conditions. Is desirable.

(1) Propylene block copolymer (A)
Is 230 ° C., 2. according to ASTM D1238.
Melt flow rate (MF) measured under a load of 16 kg
R) is 10 to 60 g / 10 min, preferably 15 to 40 g
/ 10 minutes is desirable.

The polypropylene composition containing the propylene block copolymer (A) having the above MFR value has excellent fluidity and is easy to mold a large molded article. MFR
Is less than 10 g / 10 minutes, the polypropylene composition containing a propylene block copolymer has low fluidity, poor moldability, and may not be able to mold large products.
A polypropylene composition containing a propylene block copolymer having an R exceeding 60 g / 10 minutes tends to have poor impact strength (IZ).

(2) Propylene block copolymer (A)
Desirably contains a component soluble in n-decane at 23 ° C. in an amount of 3 to 13% by weight, preferably 4 to 10% by weight. Propylene block copolymer (A) containing a rubber component (23 ° C. n-decane soluble component) in the above amount
Is excellent in flexural modulus and also in impact strength and low-temperature toughness. A polypropylene composition containing a propylene block copolymer having a rubber component amount larger than the above amount may have poor rigidity, while a polypropylene composition containing a propylene block copolymer having a rubber component too small than the above amount. The product may be inferior in impact strength and low-temperature toughness.

(3) The polypropylene component of the propylene block copolymer (A) has a melt flow rate (MFR)
But 20 to 200 g / 10 min, preferably 20 to 80 g /
It is desirable that it is 10 minutes, more preferably 20 to 60 g / 10 minutes.

The polypropylene component is composed of ¹³ C—N
It is pentad isotacticity I ₅ obtained by MR method, at least 0.97, preferably at most 0.98.

The polypropylene component has an MFR of 20 g / 10
The propylene block copolymer containing a propylene block copolymer having a MFR of less than 200 minutes has a low fluidity, is inferior in moldability, and may not be able to mold a large product. The polypropylene composition containing the copolymer has an impact strength (I
Z).

A polypropylene composition containing a propylene block copolymer having a polypropylene component I ₅ of less than 0.97 tends to have poor rigidity. (4) The propylene block copolymer (A) has an intrinsic viscosity [η] measured at 23 ° C. in decalin of 4 to 12 dl / g, preferably 5 to 8 dl / g, at 23 ° C. in n-decane. Desirably.

The n-decane-soluble component at 23 ° C. desirably contains a constituent unit derived from ethylene in an amount of 30 to 60 mol%, preferably 35 to 45 mol%.

When the constituent units derived from ethylene in the n-decane-soluble component at 23 ° C. are less than 30 mol%, or
A polypropylene composition containing more than 0 mol% of a propylene block copolymer may have poor impact strength (IZ).

The (A) propylene block copolymer used in the present invention comprises a structural unit derived from ethylene,
It is desirable that the copolymer contains 2 to 9 mol%, preferably 2 to 8 mol% in the copolymer.

A polypropylene composition containing a propylene block copolymer having a constitutional unit derived from ethylene of less than 2 mol% may have poor impact strength (IZ). Some polypropylene compositions containing a propylene block copolymer have poor rigidity.

The above n-decane soluble component at 23 ° C. was prepared by boiling 5 g of a sample (propylene block copolymer) by boiling.
This is a value calculated by immersing in 200 cc of n-decane for 5 hours to dissolve, cooling to room temperature, filtering the precipitated solid phase through a G4 glass filter, drying, and measuring the solid phase weight.

The content of the constituent unit derived from ethylene can be determined by measuring the propylene block copolymer or the n-decane-soluble component by a conventional method such as infrared spectroscopy and NMR.

The pentad isotacticity I ₅ is
Macromolec by A. Zambelli et al.
ules 6, 925 (1973), ie ¹³ C-N
It is an isotactic fraction in pentad units in a polypropylene molecular chain measured by an MR method (nuclear magnetic resonance method), and is a fraction of propylene monomer units in which five consecutive propylene units are isotactically bonded. .

The assignment of peaks in the above-mentioned NMR measurement is performed based on the description in Macromolecules 8, 687 (1975). ¹³ C-NMR is a Fourier transform NMR [5
00 MHz (at the time of hydrogen nuclei measurement)]
By performing the integration measurement at 20,000 times at 25 MHz, the measurement can be performed with the signal detection limit improved to 0.001.

In the propylene block copolymer (A) used in the present invention, the ethylene / propylene copolymer component (the component soluble in n-decane at 23 ° C.) is selected from those other than ethylene and propylene as long as the object of the present invention is not impaired. It may contain a structural unit derived from a polymerizable monomer.

Such other polymerizable monomers include:
Specifically, for example, 1-butene, 1-pentene, 1-hexene,
Α-olefins such as 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadodecene, 4-methyl-1-pentene, vinylcyclopentene, vinylcyclohexane,
Examples include vinyl compounds such as vinyl norbornane, vinyl esters such as vinyl acetate, unsaturated organic acids such as maleic anhydride, and derivatives thereof.

The propylene block copolymer (A) used in the present invention has a terpolymer of ethylene, propylene and other polymerizable monomers in the rubber part and a terpolymer of ethylene and propylene in the rubber part. It may be a mixture with a propylene block copolymer which is a copolymer.

The propylene block copolymer (A) used in the present invention comprises 3-methyl-1-butene, 3,3-dimethyl-1-butene, 3-methyl-1-pentene, 3-methyl-1 -Containing a homopolymer or copolymer such as hexene, 3,5,5-trimethyl-1-hexene, vinylcyclopentene, vinylcyclohexane, vinylnorbornane as a prepolymer formed by, for example, prepolymerization; This is preferable because the crystallization speed of the polypropylene composition is increased.

The propylene block copolymer used in the present invention as described above can be produced by various methods. For example, it can be produced using a stereoregular Ziegler-Natta catalyst. Specifically, it can be produced using a catalyst formed from a solid titanium catalyst component, an organometallic compound catalyst component, and, if necessary, an electron donor.

In the present invention, the solid titanium catalyst component specifically includes titanium trichloride or a titanium trichloride composition supported on a carrier having a specific surface area of 100 m ² / g or more. Or magnesium, a halogen, an electron donor (preferably an aromatic carboxylic acid ester or an alkyl group-containing ether) and titanium as essential components, and these essential components have a specific surface area of 100 m ² /
g of a solid titanium catalyst component supported on a carrier having a weight of at least g. Of these, the latter solid titanium catalyst component is particularly preferred.

The organometallic compound catalyst component is preferably an organoaluminum compound, and specific examples of the organoaluminum compound include trialkylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, and alkylaluminum dihalide. The organoaluminum compound can be appropriately selected according to the type of the titanium catalyst component used.

As the electron donor, an organic compound having a nitrogen atom, a phosphorus atom, a sulfur atom, a silicon atom, a boron atom or the like can be used, and preferably, an ester compound and an ether compound having the above-mentioned atoms. Is mentioned.

Such a catalyst may be further activated by a method such as co-milling, or the above-mentioned olefin may be prepolymerized. (B) Ethylene / α-olefin random copolymer The (B) ethylene / α-olefin random copolymer used in the present invention has a constitutional unit derived from ethylene of 60 to 90 mol%, preferably 75 to 90 mol%. It is contained in an amount of 85 mol%.

Examples of the α-olefin to be copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene,
1-dodecene, 1-hexadodecene and the like.

Of these, 1-butene is preferred. These α-olefins may be a combination of two or more. Further, the ethylene / α-olefin random copolymer may contain a structural unit derived from a substance other than ethylene and α-olefin, and may contain, for example, a structural unit derived from a diene as necessary. Is also good.

The structural unit derived from ethylene is 9
The polypropylene composition containing the ethylene random copolymer of 0 mol% or more may be inferior in impact resistance,
On the other hand, the polypropylene composition containing the ethylene-based random copolymer in which the constitutional unit exceeds less than 60 mol% may have poor rigidity.

The ethylene / α-olefin random copolymer (B) used in the present invention preferably has the following physical properties. (2) Intrinsic viscosity [η] measured in decalin at 135 ° C
But 1.5 to 3.5 dl / g, preferably 2.0 to 3.0 dl / g
It is desirably dl / g.

A polypropylene composition containing an ethylene / α-olefin random copolymer having an intrinsic viscosity [η] of less than 1.5 dl / g may be poor in IZ impact strength, while the intrinsic viscosity [η] is 3. Ethylene α exceeding 5 dl / g
-A polypropylene composition containing an olefin random copolymer has low fluidity and may be inferior in moldability.

(3) The glass transition temperature is −50 ° C. or lower, preferably −55 ° C. or lower, or the melting point measured as the main peak by the DSC method is 90 ° C. or lower, preferably 80 ° C. or lower, particularly Preferably, it is 70 ° C. or lower.

A polypropylene composition containing an ethylene / α-olefin random copolymer having a glass transition temperature exceeding -50 ° C. or a melting point exceeding 90 ° C. may have poor IZ impact strength.

(4) It is desirable that the crystallinity measured by the X-ray diffraction method is 20% or less, preferably 10% or less. A polypropylene composition containing an ethylene / α-olefin random copolymer having a crystallinity exceeding 20% may have poor IZ impact strength.

The ethylene / α-olefin random copolymer (B) as described above is excellent in compatibility with polypropylene, and the copolymer (B) and polypropylene are
A composition having excellent rigidity, excellent impact resistance, and excellent fluidity is formed. Further, from such a polypropylene composition, an injection-molded article having excellent appearance can be formed.

The ethylene / α-olefin random copolymer (B) as described above can be produced using a vanadium catalyst or a metallocene catalyst. (C) Fine powder talc As the (C) fine powder talc used in the present invention, conventionally known fine talc used as a modifier such as polyolefin is used.

In the present invention, the fine powder talc (C) has an average particle size of 0.5 to 20 μm and a ratio of aspect ratio to aspect ratio of at least 2 times, preferably at least 10 times. Fine powder talc is preferred. The content of the fine powder talc (C) having a particle size of 5 μm or more is desirably 5% by weight or less.

The polypropylene composition according to the present invention comprises (A) a propylene block copolymer as described above,
-80% by weight, preferably 62-72% by weight,
(B) an ethylene / α-olefin random copolymer,
It is desirable that the inorganic filler (C) is contained in an amount of 5 to 15% by weight, preferably 10 to 15% by weight, in an amount of 15 to 25% by weight, preferably 18 to 23% by weight.

The polypropylene composition according to the present invention can be obtained by a conventionally known method for preparing a resin composition from each of the above-mentioned components. Specifically, each of the components is simultaneously or successively prepared, for example, in Henschel. It is obtained by charging into a mixer, a V-type blender, a tumbler blender, a ribbon blender or the like, kneading, and then melt-kneading with a single screw extruder, a multi-screw extruder, a kneader, a Banbury mixer, or the like.

Among these, when equipment having excellent kneading performance such as a multi-screw extruder, a kneader and a Banbury mixer is used, a high-quality polypropylene composition in which each component is more uniformly dispersed can be obtained. preferable.

Although an example of the polypropylene composition according to the present invention has been described above, the polypropylene composition according to the present invention is not limited to this example as long as it satisfies the specific conditions described above. .

The polypropylene composition according to the present invention further comprises a heat-resistant stabilizer, a nucleating agent such as an aromatic carboxylate aluminum salt, an aromatic phosphate ester salt, dibenzylidene sorbitol, and an ultraviolet ray as long as the object of the present invention is not impaired. Absorbents, lubricants, antistatic agents, flame retardants, pigments, dyes, inorganic fillers other than fine powder talc, organic fillers, other polymers such as polyethylene (PE), propylene / ethylene random copolymer (EPR), etc. May be contained.

[0070]

The polypropylene composition according to the present invention comprises:
It has excellent rigidity and heat resistance, and also has various properties such as impact resistance and toughness, which are much better than conventionally known polypropylene compositions.

The injection molded article formed from the polypropylene composition according to the present invention can be used for a wide range of applications, and is particularly suitably used for automotive interior and exterior materials such as bumpers.

[0072]

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

In the following examples, each physical property was measured as follows. (1) MFR: Measured according to ASTM D1238. Conditions: 230 ° C., 2.16 kg (2) Flexural modulus (FM): Measured in accordance with ASTM D790.

Test piece 12.7 mm (width) x 6.4 mm (thickness)
× 127mm (length) 100mm between spans Bending speed 2mm / min (3) Izod impact strength (IZ): ASTM D256
It measured according to.

Temperature 23 ° C. Test piece 12.7 mm (width) × 6.4 mm (thickness) × 64 mm (length) Notch was machined. (4) Heat distortion temperature (HDT) Measured in accordance with ASTM D648.

Load 4.6 kg / cm ² (5) The size of the polypropylene microcrystals in the a-axis direction, b-axis direction and c-axis direction was determined as described above.

(6) The rubber continuous phase was determined by electron microscopy as described above. (7) The thickness of the rubber phase in the injection molded article formed from the polypropylene composition was determined as described above.

The measurement of X-ray diffraction was carried out using an RU-200A type X-ray diffractometer manufactured by Rigaku Corporation. In the following Examples and Comparative Examples, each component used when preparing the polypropylene composition is as follows. (A) Polypropylene block PP1: Propylene block copolymer (1) MFR; 20 g / 10 min (2) n-decane soluble component at normal temperature; 5% by weight (3) MFR of polypropylene component: 28 g / 10 min, (4) ) I ₅ ; 0.98 (5) Intrinsic viscosity [η] of n-decane soluble component at normal temperature: 5.5 dl
/ G (6) Structural unit derived from ethylene; 40 mol% homo PP: homopolypropylene MFR; 20 g / 10 min I ₅ ; 0.98 (B) ethylene / α-olefin random copolymer EBR-1: ethylene / 1-butene random copolymer Constituent unit derived from ethylene; 81 mol% intrinsic viscosity [η]; 2.5 dl / g Glass transition temperature (Tg); -64 ° C Crystallinity; 5% (C) talc : Average particle diameter: 2.5 μm Content of particles having a particle diameter of 5 μm or more; 3% by weight

[0079]

Examples 1-2 The components shown in Table 1 were dry blended and kneaded at 200 ° C. using a twin screw extruder to obtain a polypropylene composition.

From each of the obtained polypropylene compositions, an ASTM test piece was molded by an injection molding machine under the conditions of a resin temperature of 200 ° C. and a mold temperature of 40 ° C., and the physical properties as described above were measured for each test piece. .

Table 1 shows the results. In the injection molded product obtained in Example 1, the size of the polypropylene microcrystals was c
9.8 nm in the axial direction, 17 nm in the a-axis direction, and 18 nm in the b-axis direction. In the injection direction and the direction perpendicular to the injection direction, a continuous phase of rubber exists around the microcrystals, and the average of the rubber phase It had a phase structure repeating a structure having a thickness of 1.22 nm.

[0082]

Comparative Examples 1 and 2 ASTM test pieces were molded in the same manner as in Example 1 except that the polypropylene composition shown in Table 1 was used, and the physical properties of each test piece were measured.

Table 1 shows the results.

[0084]

[Table 1]

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mikio Hashimoto 1-2-1, Waki, Waki-machi, Kuga-gun, Yamaguchi Prefecture Inside Mitsui Petrochemical Industry Co., Ltd. (72) Inventor Satoru Moriya Kawa-gun, Yamaguchi Prefecture 6-1-2 Kimachi Waki Mitsui Petrochemical Industry Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 23/08-23/10 C08L 53/00

Claims (1)

(57) [Claims] 1. A propylene block copolymer comprising (A) 87 to 97% by weight of a crystalline homopolypropylene component and 3 to 13% by weight of an ethylene / propylene copolymer rubber component which is a 23 ° C. n-decane soluble component. (1) ASTM D12 of the propylene block copolymer
Melt flow rate (MF
R: 230 ° C., 2.16 kg load) is 10 to 60 g / 10 min, and (2) the 23 ° C. n-decane-soluble component has an intrinsic viscosity [η] of 4 to 4 measured in decalin at 135 ° C. 12 dl / g, containing 30 to 60 mol% of a structural unit derived from ethylene, and (3) the polypropylene component has an MFR of 20 to 80 g / 10
(B) (1) derived from ethylene, and 60 to 80% by weight of a propylene block copolymer having a pentad isotacticity (I ₅ ) of 0.97 or more as determined by ¹³ C-NMR method. 60 to 9 structural units
(2) intrinsic viscosity [η] measured in decalin at 135 ° C. is 1.5 to 3.5 dl / g, and (3) glass transition temperature (Tg) is −50 ° C. or less. Is there
Alternatively, an ethylene / α-olefin random copolymer 1 whose melting point measured as a main peak by the DSC method is 90 ° C. or less, and (4) crystallinity measured by the X-ray diffraction method is less than 20%
A polypropylene composition comprising 5 to 25% by weight and (C) 5 to 15% by weight of an inorganic filler and satisfying the following conditions; (i) Melt flow measured according to ASTM D1238. A rate (MFR: 230 ° C., 2.16 kg load) is 10 g / 10 min or more; (ii) a flexural modulus (FM) measured in accordance with ASTM D790 is 20,000 kg / cm ² or more; (iii) The Izod impact strength (IZ) measured according to ASTM D256 is 20 kg · cm / cm or more, and (iv) The heat distortion temperature (HDT) measured according to ASTM D648 is 135 ° C or more. (V) In the injection-molded product of the polypropylene composition, the size of polypropylene microcrystals measured by a wide-angle X-ray diffraction method and a small-angle X-ray scattering method is 5 nm to 20 nm in the c-axis direction, 5 nm to 20 in the direction
(vi) in an injection molded product of the polypropylene composition, the rubber component is formed around the polypropylene microcrystals in the injection direction and in a direction perpendicular to the injection direction. While present as a continuous phase, the rubber continuous phase has an average thickness of 0.5 nm to 3 nm.