JPH0873673A - Polypropylene-based resin composition for blow molding and blow molding using the same - Google Patents

Abstract

PURPOSE: To obtain a polypropylene-based resin composition capable of providing a blow molding excellent in stiffness and impact resistance at low temperature, having good recycling property and transparency and capable of lowering the weight. CONSTITUTION: This polypropylene-based resin composition for blow molding is composed of (A) 50-90wt.% of a propylene homopolymer having 0.05-10g/10min MI and (B) 10-50wt.% of a flexible polypropylene resin having 0.1-10g/10min MI or composed of 30-90wt.% of the component A, 1-50wt.% of the component B and 10-70wt.% of the propylene copolymer C component having 0.05-100g/10min MI. Blow molding is obtained by molding this composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene resin composition for blow molding and a blow molding using the same.
More specifically, a polypropylene-based resin composition having excellent rigidity and low-temperature impact resistance, and having good recyclability or transparency as well as providing a hollow molded article capable of reducing the weight,
It also relates to a hollow molded article obtained by molding the polypropylene resin composition.

[0002]

2. Description of the Related Art Polypropylene resin is used as a material for hollow molded articles useful as various containers because it has good rigidity and transparency and excellent chemical resistance and hygienic properties. However, polypropylene resin has a drawback that it has low impact strength, in particular, low impact resistance at low temperatures, and improvement in low temperature impact resistance is essential for use as a hollow molded article. Conventionally, a polyethylene resin and an ethylene-propylene copolymer rubber (EPR) have been blended with the polypropylene resin for the purpose of improving the low-temperature impact resistance of the polypropylene resin (Japanese Patent Publication No. 58-38459, Japanese Patent Publication No. Kaisho 53-799
No. 39, Japanese Patent Publication No. 5-88264, and Japanese Unexamined Patent Publication No. 2-
208339, JP-A-5-124092). However, in a hollow molded article produced from such a conventional polypropylene-based resin composition, by incorporating a rubber component, the transparency originally possessed by the polypropylene resin is lowered, and a different material is incorporated. Therefore, it has drawbacks such as poor recyclability.

[0003]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of the prior art, is excellent in rigidity and low temperature impact resistance, has good recyclability and transparency, and is capable of reducing the basis weight. It is an object of the present invention to provide a polypropylene resin composition which gives a hollow molded article, and a hollow molded article obtained by molding the same.

[0004]

The inventors of the present invention have conducted extensive studies to achieve the above object. As a result, a resin composition containing a propylene homopolymer having a melt index in a specific range and a soft polypropylene resin at a predetermined ratio, respectively, is excellent in rigidity and low temperature impact resistance,
Further, they have found that the hollow molded article has good recyclability because it does not contain many different kinds of materials, and at the same time, it gives a hollow molded article capable of reducing the basis weight. Further, the present inventor has found that a resin composition containing a propylene homopolymer having a melt index in a specific range, a soft polypropylene resin, and a propylene copolymer composition at predetermined ratios has high rigidity and low temperature resistance. It has been found that it gives a hollow molded article which has excellent impact properties, particularly good transparency, and can be reduced in weight. The present invention has been completed based on such findings.

That is, in the present invention, 50 to 90% by weight of propylene homopolymer (A) melt index of 0.05 to 10 g / 10 min, and (B) melt index of
0.1 ~ 10g / 10min soft polypropylene resin 50 ~
Polypropylene resin composition for blow molding comprising 10% by weight, (A) melt index of 0.05 to 10 g / 1
30 to 90% by weight of propylene homopolymer for 0 minutes, (B)
A soft polypropylene resin having a melt index of 0.1 to 10 g / 10 minutes and 1 to 50% by weight, and (C) a propylene copolymer composition having a melt index of 0.05 to 100 g / 10 minutes and 10 to 70% by weight. Provided are a polypropylene resin composition for blow molding, and a blow molded product obtained by molding the above polypropylene resin composition.

In the resin composition of the present invention, the propylene homopolymer used as the component (A) must have a melt index (MI) in the range of 0.05 g / 10 minutes. If this MI is less than 0.05 g / 10 minutes,
Moldability is poor, and if it exceeds 10 g / 10 minutes, resin dripping may occur during molding, and a good molded body may not be obtained.
The preferred MI range is 0.1 to 5 g / 10 minutes. The propylene homopolymer as the component (A) contributes to improvement in rigidity and transparency. The method for producing the propylene homopolymer is not particularly limited, and a conventionally known method can be used. For example, in the presence of a Ziegler type catalyst, specifically a polymerization catalyst composed of a halogen compound of a transition metal such as titanium trichloride and an organoaluminum compound,
By homopolymerizing propylene by a slurry polymerization method, a gas phase polymerization method, a bulk polymerization method, a solution polymerization method, or the like,
A propylene homopolymer of the component (A) is obtained.

In the resin composition of the present invention, the soft polypropylene resin used as the component (B) has an MI of 0.
It is necessary to be in the range of 1 to 10 g / 10 minutes. If this MI is less than 0.1 g / 10 minutes, the moldability is poor and 10
If it exceeds g / 10 minutes, resin sagging may occur during molding, and a good molded product may not be obtained. The preferred MI range is 0.5-6 g / 10 minutes. Within this preferable MI range, the moldability becomes even better. The soft polypropylene resin as the component (B) contributes to the improvement of low-temperature impact resistance, and in particular, (a) (a) the intrinsic viscosity [η] measured in decalin at a temperature of 135 ° C. is 0.5 to 0.5. 10 deciliter / g, preferably 1.0-9.0 deciliter / g
And (b) the boiling n-heptane insoluble component amount (W) is 10 to
99% by weight, preferably 20-99% by weight, and (C) the relaxation time of the rubber component measured by pulse NMR at a temperature of 30 ° C. [T _2H ^R (30): μs] and 80
Measured value in ° C [T _2H ^R (80): μs] and the above boiling n
-The relationship with the amount of heptane-insoluble component (W) is expressed by the formula T _2H ^R (80) ≦ 670−2.2 × W T _2H ^R (80) / T _2H ^R (30) ≦ 8.8 + 0.086 × W Satisfying propylene homopolymer and / or copolymers containing less than 4 mol% of other olefin units 10-95
% By weight, preferably 30-95% by weight, and (b) temperature 1
The intrinsic viscosity [η] measured in decalin at 35 ° C is 0.5-
10 deciliter / g, preferably 1.0 to 9.0 deciliter / g olefin units other than propylene 10
A propylene-based random copolymer containing 80 mol%, preferably 10 to 70 mol%, 90 to 5 wt%, preferably 70 to 5 wt% is suitable.

In the above-mentioned component (a), a propylene homopolymer and / or a copolymer containing 4 mol% or less of other olefin units, if the intrinsic viscosity [η] is less than 0.5 deciliter / g, mechanical properties Is insufficient, and if it exceeds 10 deciliter / g, the moldability is deteriorated. Also, boiling n
-If the heptane insoluble content (W) deviates from the above range,
The object of the present invention cannot be fully achieved. The amount of the insoluble component (W) is a value expressed as a weight fraction of the boiling n-heptane-insoluble component as the extraction residue after extraction with boiling n-heptane for 6 hours using a Soxhlet-extraction tester. . Further, the homopolymer or copolymer of propylene is pulse N
The relaxation time of the rubber component measured by MR was measured at a temperature of 30 ° C. [T _2H ^R (30): μs] and at 80 ° C. [T _2H ^R (80): μs], and the boiling n-heptane-insoluble If the relationship with the component amount (W) does not satisfy the above formula, the object of the present invention cannot be sufficiently achieved. Regarding the measuring method of the relaxation time (T _2H ^R ) of the rubber component by the above-mentioned pulse NMR, the measurement nucleus was set to ¹ H at a measurement frequency of 90.1 MHz using a CXP-90NMR apparatus manufactured by Nippon Bruker Co., Ltd. The pulse sequence was measured by the solid echo method. Observation pulse width 2.0 μsec, FID (free induction decay)
The waiting time until the next pulse was given after the observation was 5 seconds and the number of integration was 300 times.

On the other hand, in the propylene random copolymer as the component (b), if the intrinsic viscosity [η] is less than 0.5 deciliter / g, the mechanical properties are insufficient, and if it exceeds 10 deciliter / g, the Sex deteriorates. In addition, in this soft polypropylene resin, the component (a) and the component (b)
If the content ratio with the components deviates from the above range, the object of the present invention cannot be sufficiently achieved. The soft polypropylene resin as the component (B) can be prepared, for example, by various polymerization methods such as a gas phase multi-step polymerization method and a slurry multi-step polymerization method, or a blending method. When prepared by a polymerization method, for example, a solid catalyst component composed of magnesium, titanium, a halogen atom, an electron donor, and a crystalline polyolefin optionally used, an organoaluminum compound and an alkoxy group-containing aromatic compound are required. Propylene and other olefins may be subjected to multi-stage polymerization in the presence of a polymerization catalyst composed of an electron donor used according to the above. The polymerization order and the number of polymerization stages in the multi-stage polymerization can be arbitrarily selected. For example, propylene homopolymerization can be performed in the first polymerization (first stage polymerization), and ethylene-propylene copolymerization or ethylene-propylene-polyene copolymerization can be performed in the second and subsequent stages. Polyenes that can be used include
Examples thereof include dicyclopentadiene and tricyclopentadiene. The polymerization method is not particularly limited, and slurry polymerization, gas phase polymerization, bulk polymerization, solution polymerization and the like can be used. When prepared by a blending method, a propylene homopolymer and an ethylene-propylene copolymer and / or an ethylene-propylene-polyene copolymer may be blended by a known method (for example, dry blending or kneading). Good.

In the resin composition of the present invention, the propylene copolymer composition used as the component (C) has MI
It should be in the range of 0.05 to 100 g / 10 minutes. If the MI is less than 0.05 g / 10 minutes, the moldability is poor, and if it exceeds 100 g / 10 minutes, the impact resistance is lowered. The preferable MI range is 0.1 to 50 g / 10 minutes, and in this range, excellent moldability and impact resistance can be obtained. The propylene copolymer composition as the component (C) contributes to improvement of transparency and impact resistance, and particularly, the intrinsic viscosity [η] of (c) is 0.5 to 6 deciliter / g, preferably Is 0.8 to 4 deciliters / g propylene homopolymer 65 to 98% by weight, preferably 70
To 95% by weight, and (d) intrinsic viscosity [η] gas 0.8 to 10
Deciliter / g, preferably 1-8 deciliter / g
And the content of the α-olefin unit having 5 or more carbon atoms is 5% by weight or more, preferably 10% by weight or more, the propylene-α-olefin (having 5 or more carbon atoms) copolymer 35.
It is suitable that the amount is ˜2% by weight, preferably 30 to 5% by weight.

In the propylene homopolymer of the component (c), if the intrinsic viscosity [η] is less than 0.5 deciliter / g, the impact resistance is poor, and if it exceeds 6 deciliter / g,
Moldability deteriorates. On the other hand, the component (d), propylene-α-
When the intrinsic viscosity [η] of the olefin copolymer is less than 0.8 deciliter / g, the impact resistance is insufficient, and 1
When it exceeds 0 deciliter / g, the moldability deteriorates. If the content of the α-olefin unit having 5 or more carbon atoms is less than 5% by weight, the effect of improving the impact resistance cannot be sufficiently exhibited. The α-olefin constituting the propylene-α-olefin copolymer which is the component (d) is an α-olefin having 5 or more carbon atoms. Specifically, pentene-1,
Linear olefins such as hexene-1, decene-1 and 4-
Branched olefins such as methylpentene-1; 3-methylbutene-1; vinylcyclohexane and the like can be mentioned, and among them, linear olefins having 6 or more carbon atoms are particularly preferable. These olefins may be used as a mixture of two or more. If the α-olefin has 4 or less carbon atoms, the effect of improving transparency and impact resistance cannot be sufficiently exhibited. Further, if the content of the component (d) is less than 2% by weight, the effect of improving impact resistance is not sufficiently exerted, and 35
When it exceeds the weight%, the rigidity decreases.

The method for producing the propylene copolymer composition as the component (C) is not particularly limited, and various known methods can be used. For example, for the propylene homopolymer of the component (c), propylene is homopolymerized in the presence of a Ziegler type catalyst, specifically, a polymerization catalyst composed of a halogen compound of a transition metal such as titanium trichloride and an organic aluminum compound. You can do it. Also,
The propylene-α-olefin copolymer of the component (d) is
Subsequent to the polymerization of the component (c), propylene and an α-olefin having 5 or more carbon atoms are introduced into the same polymerization tank to proceed the copolymerization, and at the same time, (c),
(D) It is also possible to obtain a propylene copolymer composition comprising both components. After polymerizing the component (c) in the first polymerization tank, the composition is transferred to the second polymerization tank without losing the catalytic activity, Therefore, the component (d) can be polymerized to obtain a propylene copolymer composition. Alternatively, the component (c) and the component (d) may be produced in separate polymerization tanks, and then both components may be mixed to obtain the desired propylene copolymer composition. As the polymerization method, for example, slurry polymerization, solution polymerization, gas phase polymerization, bulk polymerization, etc. are used.

In the present invention, as a polypropylene resin composition for blow molding, (1) 50 to 90% by weight of a propylene homopolymer as the component (A) and 50 to 10% by weight of a soft polypropylene resin as the component (B). And a propylene homopolymer 30 of component (2) (A)
~ 90 wt% and (B) component soft polypropylene resin 1
Provided is a resin composition comprising about 50% by weight and 10 to 70% by weight of the propylene copolymer composition as the component (C). The resin composition of (1) above has excellent rigidity and low-temperature impact resistance,
In addition, it has characteristics such as being able to reduce the weight, (A)
If the blending ratio of the component and the component (B) deviates from the above range, this characteristic will not be sufficiently exhibited. The preferred mixing ratio is 60 to 85% by weight of the component (A) and 40 to the component (B).
15% by weight. Moreover, since this composition does not contain many different kinds of components, the obtained hollow molded article has good recyclability. On the other hand, the resin composition of the above (2) has characteristics such as excellent rigidity and low temperature impact resistance, capable of reducing the basis weight, and also particularly excellent in transparency, and the components (A), (B) and If the blending ratio of the component (C) deviates from the above range, this property will not be sufficiently exhibited. A preferable blending ratio is 35 to 80% by weight of the component (A), 3 to 40% by weight of the component (B) and 20 to 65% by weight of the component (C).

The polypropylene resin composition for blow molding of the present invention may optionally contain various additives such as antioxidants, ultraviolet absorbers, lubricants, nucleating agents, etc. within the range not impairing the object of the present invention. Antistatic agents, flame retardants, colorants, inorganic or organic fillers, etc. can be added. The method for preparing the polypropylene-based resin composition of the present invention is not particularly limited, and conventionally known methods such as V-blender, ribbon blender, and Henschel mixer are used as essential components and various additive components used as desired. The method of mixing with a mixer, the method of kneading with a kneader such as an extruder, a mixing roll, a Banbury mixer, or a kneader, or the method of mixing and kneading with a combination of a mixer and a kneader can be used.

The present invention also provides a hollow molded article obtained by molding the polypropylene resin composition thus prepared. As a method for molding the hollow molded body, various commonly used methods can be adopted. For example, a polypropylene resin composition is melted and plasticized, a parison is extruded from a die head by screw rotation, a plunger extrusion, an accumulator, and the like, and then a split mold having a concave mold for giving a bottle shape is closed to mold the parison. It is sandwiched between molds, and then a pressurized fluid is pressed into the parison to expand the parison (blow molding method), a bottomed parison is molded by injection molding, and this is mounted in a mold and pre-blown. And stretch-blow after adjusting the stretch temperature (injection stretch-blow molding method)
For example, a hollow molded body can be obtained.

[0016]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Production Example 1 Production of Soft Polypropylene Resin (1) Preparation of Magnesium Compound A glass reactor equipped with a stirrer (internal volume of about 6 liters) was sufficiently replaced with nitrogen gas, and ethanol of about 2,430 g, iodine of 16 g and magnesium metal was prepared. 160 g was added, and the mixture was reacted under heating under reflux conditions with stirring until no hydrogen gas was generated from the inside of the system to obtain a solid reaction product. The reaction mixture containing this solid product was dried under reduced pressure to obtain a magnesium compound. (2) Preparation of solid catalyst component (A) In a glass reactor having an internal volume of 5 liters which was sufficiently replaced with nitrogen gas, 160 g of the magnesium compound (not crushed) obtained in the above (1) and purified heptane 800 After adding milliliters, 24 milliliters of silicon tetrachloride and 23 milliliters of diethyl phthalate, keeping the system temperature at 80 ° C, adding 770 milliliters of titanium tetrachloride with stirring and reacting at 110 ° C for 2 hours, and then separating solid components. The purified heptane at 90 ° C was washed. Further, 1220 ml of titanium tetrachloride was added, and the mixture was reacted at 110 ° C. for 2 hours and then sufficiently washed with purified heptane to obtain a solid catalyst component (A).

(3) Gas Phase Polymerization The solid catalyst component (A) obtained in the above (2) was added to 6.0 in a polymerization tank at the front stage of a continuous gas phase polymerization apparatus having an internal volume of 200 liters.
g / h, triisobutylaluminum (TIBA)
0.2 mol / hour, 1-allyl-3,4-dimethoxybenzene (ADMB) 0.012 mol / hour, diphenyldimethoxysilane (DPDMS) 0.006 mol / hour, and propylene were supplied at 37 kg / hour, 70 ℃, 28kg
/ Cm ² G It was polymerized.

The intrinsic viscosity [η] of the obtained polymer (13)
5 ° C. in decalin) was 4.27 dl / g. Also,
The boiling n-heptane insoluble matter [η] of this polymer was 4.8.
1 dl / g, boiling n-heptane solubles [η] 2.61d
It was 1 / g. The amount of polymer produced in the polymerization tank at this time was 30 kg / hour. The boiling n-heptane insoluble component amount (W) of this polymer was 62.5% by weight. Also, the measured relaxation time obtained by pelletizing the sampling powder is T _2H ^R (30) 42.1μs T _2H ^R (80) 530μs T _2H ^R (80) / T _2H ^R (30) 12.6. there were.

Then, the above-mentioned polymer was continuously transferred to a polymerization tank in the subsequent stage. In the latter polymerization tank, add 1 ethylene
5 kg / hour and propylene are supplied at 5 kg / hour,
Polymerization was carried out at 50 ° C. and 15 kg / cm ² G to obtain a polymer having a total intrinsic viscosity [η] of 4.77 dl / g, an ethylene unit content of 16.5% by weight, and a reaction ratio of 37.5% in the latter stage. It was Increase the amount of 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane mixed in the obtained powder, and further add an antioxidant, a heat stabilizer, and a chlorine scavenger to the mixture. After mixing, the mixture was extruded with a 40 mmφ extruder to obtain pellets having MI of 2.5 g / 10 min.

Production Example 2 Production of Propylene Copolymer Composition Dehydration was carried out in an autoclave equipped with a stirrer and having an internal volume of 10 liters.
-Add 5 liters of heptane, add 5 ml of diethylaluminum chloride and 0.6 g of titanium trichloride (manufactured by Marubeni Solvay), and add propylene (pressure 1 kg / cm
² G) was supplied and prepolymerization was carried out at 25 ° C. for 30 minutes.
Next, the liquidus temperature was maintained at 65 ° C., hydrogen was metered so that the produced polypropylene had a predetermined intrinsic viscosity, and then propylene was continuously added so that the reaction pressure became 8 kg / cm ² G. And was polymerized while stirring for 90 minutes to obtain a propylene homopolymer. Then, unreacted propylene was removed. Then, in the above autoclave, while maintaining the temperature at 57 ° C, 5 ml of triethylaluminum, a predetermined amount of hydrogen and hexene-1 were added.
Was added, propylene was continuously supplied so that the reaction pressure was 2 kg / cm ² G, and polymerization was performed for 120 minutes to obtain a propylene-hexene-1 copolymer. After the reaction,
The unreacted monomer was removed, the polymerization product was separated, and a propylene copolymer composition in the form of white powder was manufactured through a washing step and a drying step. This propylene copolymer composition has M
Propylene homopolymer component 83 with I of 11 g / 10 min
% By weight and 17% by weight of the propylene-hexene-1 copolymer component, and the physical properties of each component were as shown below. Physical properties of propylene homopolymer component Intrinsic viscosity [η]: 1.36 dl / g Physical properties of propylene-hexene-1 copolymer component Hexene-1 unit content: 21% by weight Intrinsic viscosity [η]: 3.8 dl / g

Examples 1 to 7 and Comparative Example 1 Polypropylene using the types and amounts of the components shown in Table 1
System resin composition is prepared and manufactured by Japan Steel Works, Ltd. 50mmφ hollow
Using a molding machine (L / D = 20, CR = 1.6),
A: 16/14 mmφ, molding temperature: C₁, C₂, C₃,
AD, H₁, H ₂, D = 190 ℃_,200 ° C, 210
℃, 230 ℃, 230 ℃, 230 ℃, 230 ℃, mold temperature
Degree: Round shape with a rated capacity of 500 ml at 20 ° C
A container was made. Obtain the physical properties of this container as shown below.
I have (1) Buckling strength Large compression tester (TENSIL) manufactured by Toyo Seiki Seisakusho Ltd.
ON / CTN-I-5000) with an empty container
, And perform a compression test at a compression speed of 12.5 mm / min.
The maximum force exerted by the deforming container during this compression test is
The buckling strength is the force at the point of time. (2) Transparency (Haze) Haze measurement tester manufactured by Nippon Denshoku Industries Co., Ltd. (SZ-Σ90)
It was used and measured according to JIS K-7105. What
For the measurement, the body of a 500 ml round container
A 50 × 50 mm test piece cut from was used. (3) Bottle drop strength Using a small incubator (SC-65) manufactured by Satake Co., Ltd.
Let the container containing the rated volume of water stand in a thermostat at 5 ° C for 30 hours.
After placing, drop 10 containers from a height of 120 cm
Measure the presence or absence of container cracking, and follow the criteria below.
The drop strength was evaluated. ⊚: 10 pieces are not cracked ◯: 1-2 pieces are broken in 10 pieces ×: 3 pieces or more are broken in 10 pieces The results are shown in Table 2.

[0022]

[Table 1]

[0023] Note 1) propylene homopolymer: Idemitsu Petrochemical Co., Ltd. E105GM, MI = 0.6g / 10 min, density = 0.90g / cm ³ 2) soft polypropylene resin: obtained in Preparation Example 1 3) Propylene copolymer composition: the one obtained in Production Example 2

[0024]

[Table 2]

80% by weight of a propylene homopolymer [E105GM manufactured by Idemitsu Petrochemical Co., Ltd., MI = 0.6 g / 10 min, density = 0.90 g / cm ³ ] and polyethylene resin (linear low-density polyethylene) , MI = 2 g / 10 min, density = 0.920 g / cm ³ ) 14% by weight and EPR (ethien-propylene copolymer rubber, MI = 0.4 g / 10 min,
A resin composition having a density of 0.880 g / cm ³ ) 6% by weight was prepared, and a round container having a rated capacity of 500 ml was prepared in the same manner as described above, and its physical properties were evaluated. It was Unit weight: 30g Buckling strength: 29kg Haze: 54% Bottle drop strength: ◎

[0026]

EFFECT OF THE INVENTION The polypropylene resin composition for blow molding of the present invention is excellent in rigidity and impact resistance at low temperature, has good recyclability or transparency, and can give a blow molded product capable of reducing the basis weight. it can. The hollow molded article obtained from the polypropylene resin composition is effectively used as various containers.

Claims (5)

[Claims] 1. A melt index of (A) of 0.05 to 1
50 to 90% by weight of a propylene homopolymer of 0 g / 10 minutes, and (B) a melt index of 0.1 to 10 g / 1.
A polypropylene resin composition for blow molding, which comprises 50 to 10% by weight of a soft polypropylene resin for 0 minutes. 2. (A) Melt index is 0.05 to 1
30 to 90% by weight of propylene homopolymer of 0 g / 10 minutes, (B) 1 to 50% by weight of soft polypropylene resin having a melt index of 0.1 to 10 g / 10 minutes, and (C)
A polypropylene resin composition for blow molding, comprising 10 to 70% by weight of a propylene copolymer composition having a melt index of 0.05 to 100 g / 10 min. 3. The soft polypropylene resin as the component (B) has an intrinsic viscosity [η] of 0.5 to 10 deciliter / g measured in (a) (a) decalin at a temperature of 135 ° C.,
(B) Boiling n-heptane insoluble component amount (W) is 10 to 99.
%, And the relaxation time of the rubber component measured by (c) pulse NMR at a temperature of 30 ° C. [T _2H ^R (3
0): μs] and the measured value at 80 ° C. [T _2H ^R (80): μ
s] and the boiling n-heptane insoluble component amount (W) are expressed by the formula T _2H ^R (80) ≦ 670−2.2 × W T _2H ^R (80) / T _2H ^R (30) ≦ 8. Propylene homopolymer satisfying 0.8 + 0.086 × W and / or copolymer containing 10 to 95 mol% of other olefin units.
Propylene-based random copolymerization containing 10% by weight and (b) 10 to 80 mol% of olefin units other than propylene having an intrinsic viscosity [η] of 0.5 to 10 deciliter / g measured in decalin at a temperature of 135 ° C. The polypropylene resin composition for blow molding according to claim 1 or 2, which comprises 90 to 5% by weight of the combined product. 4. The propylene copolymer composition of the component (C) has an intrinsic viscosity (η) of 0.5 to 6 deciliters / g.
The propylene homopolymer of 65 to 98% by weight and (d) the intrinsic viscosity [η] is 0.8 to 10 deciliter / g, and the content of the α-olefin unit having 5 or more carbon atoms is 5% by weight or more. The polypropylene resin composition for blow molding according to claim 2, which comprises 35 to 2% by weight of a propylene-α-olefin (having 5 or more carbon atoms) copolymer. 5. A hollow molded article obtained by molding the polypropylene resin composition according to claim 1.