JP2002179860A - Polypropylene resin composition, container and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylene resin composition which is excellent in injection stretch blow moldability, and at the same time improves rigidity, gloss, transparency, flexibility and impact resistance in a well-balanced manner,
Provided are a polypropylene resin composition capable of obtaining a container having excellent squeezing properties, and a container comprising the resin composition. SOLUTION: (A) Melt flow rate (ASTM)
D 1238, 230 ° C, 2.16 kg load) 20 to
60 g / 10 min, molecular weight distribution (Mw / Mn) determined by gel permeation chromatography is 2.2
(B) nucleating agent 0.05 to 100 parts by weight of polypropylene resin having an ethylene content of 2 to 4% by weight.
A polypropylene resin composition containing 0.5 parts by weight, and a container comprising the resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition, a container made of the resin composition, and a method for producing the container. In particular, the present invention is excellent in injection stretch blow moldability, and has rigidity, gloss, transparency, flexibility and flexibility. The present invention relates to a polypropylene resin composition having an excellent balance of impact resistance, a container made of this resin composition having excellent squeezability, and a method for producing a container.

[0002]

2. Description of the Related Art Generally, polypropylene resin has heat resistance,
Because of its excellent chemical properties, physical properties, and moldability, and its low cost, it is mainly used for a wide range of applications as injection molded products or films. However, polypropylene resins have not been used much for hollow container applications. One of the reasons is that the content of the polypropylene resin is dull because the transparency of the polypropylene resin is not always sufficient as compared with the polyester resin or the polystyrene resin.

[0003] As a method of molding a hollow plastic container, there is a direct blow molding method in which a parison is molded from a molten resin, the parison is sandwiched by a mold, and then a pressurized gas is blown into the parison to form the container. There is an injection stretch blow molding method in which a preform is once formed by injection molding or extrusion molding, and the preform is stretch blow molded.

Since a polypropylene resin has a low melt tension, it is difficult to obtain a good molded container by direct blow molding as it is, so that the injection stretch blow molding method is often used for molding the container. But,
Since polypropylene resin is a resin that easily crystallizes,
Also in the injection stretch blow molding method, there is a problem that the preform is easily crystallized, and as a result, uniform stretching of the preform is often difficult, and it is difficult to obtain a good product.

In general, a plastic container needs to be self-supporting and have rigidity so that it does not deform even when the contents are filled, and have mechanical strength such as impact resistance that does not break even when dropped with the contents filled. It is required to be excellent. Also, plastic containers are required to have a squeezing property such that the folds do not turn white even when the container is crushed when taking out the contents.However, containers obtained from polypropylene resin have insufficient squeezing properties, and when taking out the contents, There is a problem that the fold is creased and the fold becomes white.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polypropylene resin composition which is excellent in injection stretch blow moldability and at the same time improves rigidity, gloss, transparency, flexibility and impact resistance in a well-balanced manner. Another object of the present invention is to provide a polypropylene resin composition capable of obtaining a container having excellent squeezing properties, a container comprising the resin composition, and a method for manufacturing a container.

[0007]

The present invention provides the following polypropylene resin composition, container, and method for producing the same. (1) (A) Melt flow rate (ASTM D 1
238, 230 ° C, 2.16kg load) 20-60g
/ 10 minutes, the molecular weight distribution (Mw / Mn) determined from gel permeation chromatography is 2.2 to 4.
0, 100 parts by weight of a polypropylene resin having an ethylene content of 2 to 4% by weight, and (B) a nucleating agent of 0.05 to 0.1%.
A polypropylene resin composition containing 5 parts by weight. (2) The content of α-olefins other than propylene and ethylene in the polypropylene resin (A) is 0 to 2% by weight.
The polypropylene resin composition according to the above (1), wherein (3) The above (1) or (2), wherein the polypropylene resin (A) is a polypropylene resin obtained by thermal degradation.
The polypropylene resin composition according to the above. (4) The polypropylene resin composition according to any one of the above (1) to (3), wherein the polypropylene resin (A) contains a polypropylene resin thermally degraded at least twice. (5) Any one of the above (1) to (4), wherein the polypropylene resin (A) is obtained by thermal degradation by melt-kneading the polypropylene resin (C) in the presence of an organic peroxide. The polypropylene resin composition according to the above. (6) The above-mentioned (5), wherein the polypropylene resin (C) contains a thermally degraded polypropylene resin (C-1) and a thermally degraded polypropylene resin (C-2).
The polypropylene resin composition according to the above. (7) The above-mentioned polypropylene resin (C) which contains 80 to 98% by weight of the thermally degraded polypropylene resin (C-1) and 2 to 20% by weight of the thermally degraded polypropylene resin (C-2). The polypropylene resin composition according to (5) or (6). (8) Non-thermally degraded polypropylene resin (C-
The polypropylene resin composition according to the above (6) or (7), wherein 1) is a propylene / α-olefin random copolymer. (9) Non-thermally degraded polypropylene resin (C-
The polypropylene resin composition according to the above (6) or (7), wherein 1) is a propylene / ethylene random copolymer. (10) Thermally degraded polypropylene resin (C-2)
Is a propylene / α-olefin random copolymer (D-
The polypropylene resin composition according to any one of the above (6) to (9), which is obtained by thermally degrading a mixture containing 1) and a propylene homopolymer (D-2). (11) Thermally degraded polypropylene resin (C-2)
Is a propylene / α-olefin random copolymer (D-
1) 80 to 98% by weight of propylene homopolymer (D-
2) The polypropylene resin composition according to any one of the above (6) to (10), which is obtained by thermally degrading a mixture containing 2 to 20% by weight. (12) The polypropylene resin composition according to the above (10) or (11), wherein the propylene / α-olefin random copolymer (D-1) is a propylene / ethylene random copolymer. (13) The nucleating agent (B) is an organic phosphate compound,
(1) to (12) which are at least one selected from the group consisting of sorbitol compounds, C _{4 to} C ₁₂ aliphatic dicarboxylic acids or metal salts thereof, aromatic carboxylic acids or metal salts thereof, and rosin chloride compounds. The polypropylene resin composition according to any one of the above. (14) The organic phosphate compound is represented by the following formula (1):
Or the polypropylene resin composition according to the above (13), which is a compound represented by (2).

Embedded image (In the formula (1) or (2), R ¹ is a group having 1 to 10 carbon atoms.
A divalent hydrocarbon group, R ² and R ³ are hydrogen or C 1 -C
10 hydrocarbon groups. R ² and R ³ may be the same or different. M is a metal atom having 1 to 3 valences, and n is 1
-3. m is 1 or 2. (15) A container comprising the polypropylene resin composition according to any one of (1) to (14). (16) A method for manufacturing a container, comprising: forming a preform by injection molding the polypropylene resin composition according to any one of the above (1) to (14), and then stretch blow molding the preform to manufacture a container. .

In the present specification, “squeezing property” means
Even if the container or sheet made of the polypropylene resin composition is crushed, the fold does not become white even when crushed, and means that the original shape can be easily restored when an external force is applied.

<< Polypropylene Resin (A) >> As the polypropylene resin (A) which is a main component of the polypropylene resin composition of the present invention, the melt flow rate, the molecular weight distribution (Mw / Mn) and the ethylene content are specified below. Can be used without limitation. For example, as long as the physical properties described later are satisfied, one kind of polypropylene resin may be used, or two or more kinds of polypropylene resins may be contained. Further, the polymerization method and the production method are not limited. When two or more types of polypropylene resins are contained, the physical properties of the mixture as a whole need only satisfy the physical properties described below.

The physical properties of the polypropylene resin (A) used in the present invention are as follows.・ Melt flow rate (MFR: ASTM D 123)
8, 230 ° C., 2.16 kg load, the same applies hereinafter unless otherwise specified) is 20 to 60 g / 10 min, preferably 2
5 to 55 g / 10 min, more preferably 30 to 50 g /
10 minutes.・ Gel permeation chromatography (GPC)
Molecular weight distribution (weight average molecular weight (Mw) /
The number average molecular weight (Mn) is 2.2 to 4.0, preferably 2.5 to 3.8, and more preferably 2.7 to 3.5. -An ethylene content of 2 to 4% by weight, preferably 2.3 to
3.8% by weight, more preferably 2.6 to 3.8% by weight.

[0011] Since the MFR of the polypropylene resin (A) is within the above range, the polypropylene resin composition of the present invention is excellent in injection stretch blow moldability, and a molded article molded from this resin composition has a high mechanical strength. In addition, the balance between transparency and gloss is improved, and a molded article having a good appearance can be obtained.

Further, since the molecular weight distribution (Mw / Mn) of the polypropylene resin (A) is in the above range, the polypropylene resin composition of the present invention has excellent injection stretch blow moldability, and is molded from this resin composition. The molded article is excellent in transparency and gloss. The molecular weight distribution is GP
In method C, using o-dichlorobenzene as an elution solvent,
It is a polystyrene conversion value measured using monodisperse polystyrene as a standard substance.

Examples of the polypropylene resin constituting the polypropylene resin (A) include a propylene / α-olefin random copolymer, a propylene / α-olefin block copolymer, and a propylene homopolymer.
Examples of the α-olefin copolymerized with propylene include olefins having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, such as ethylene, 1-butene, 1-pentene and 4-olefin.
Methyl-1-pentene, 1-hexene, 1-heptene,
Examples thereof include 1-octene, 1-decene, 1-dodecene, and 1-hexadecene. Of these, ethylene is preferred.

The content of α-olefins other than propylene and ethylene in the polypropylene resin (A) is from 0 to 2% by weight, preferably from 0 to 1.5% by weight, in terms of balance between mechanical strength, squeezing property and transparency. %, More preferably 0 to 0.5% by weight. The propylene content of the polypropylene resin (A) is 96 to 98% by weight,
Preferably it is 96.2 to 97.7% by weight, more preferably 96.2 to 97.4% by weight.

[0015] The polypropylene resin (A) can be produced by a known method. For example, in the presence of a stereoregular olefin polymerization catalyst containing a transition metal compound component such as a titanium-based or zirconium-based component, an organoaluminum component, an electron donor if necessary, a carrier, and the like, propylene, ethylene, By polymerizing an α-olefin of the formula (1). It can also be obtained by thermally degrading a polypropylene resin by a known method.

The polypropylene resin (A) is preferably a polypropylene resin obtained by thermal degradation, and particularly preferably contains a polypropylene resin thermally degraded two or more times. The thermally degraded polypropylene resin easily satisfies the molecular weight distribution.

As the polypropylene resin (A) preferably used in the present invention, the polypropylene resin (C) is melt-kneaded in the presence of an organic peroxide to reduce the molecular weight (thermal degradation) and narrow the molecular weight distribution. Polypropylene resin. When a polypropylene resin obtained by thermal degradation is used as the polypropylene resin (A), the physical properties of the polypropylene resin before thermal degradation are not particularly limited, and the properties after thermal degradation include the MFR, molecular weight distribution, and ethylene content. You only have to satisfy the quantity.

The polypropylene resin (C) preferably contains a thermally degraded polypropylene resin (C-1) and a thermally degraded polypropylene resin (C-2). Non-thermally degraded polypropylene resin (C-
The content of 1) is 80 to 98% by weight, preferably 80 to 9%.
0% by weight, thermally degraded polypropylene resin (C-2)
Is desirably 2 to 20% by weight, preferably 10 to 20% by weight.

It is desirable that the ethylene content of the polypropylene resin (C) is 3 to 4% by weight, preferably 3.5 to 3.9% by weight. The content of α-olefins other than propylene and ethylene in the polypropylene resin (C) is 0.
%, Preferably 0 to 1.5% by weight, more preferably 0 to 0.5% by weight.

The melt flow rate (MFR (230 ° C.)) of the polypropylene resin (C) is 8 to 20 g / 10 minutes,
Preferably 8 to 15 g / 10 min, more preferably 8 to 15 g / 10 min.
Desirably, it is 11 g / 10 minutes. Mw / Mn of the polypropylene resin (C) is 3 to 5, preferably 3.2 to 2.
It is desirable to be 4.8, more preferably 3.5-4.5.

The polypropylene resin (C-1) which has not been thermally degraded is preferably a propylene / α-olefin random copolymer, particularly preferably a propylene / ethylene random copolymer. Α-olefins other than propylene and ethylene have 4 to 20 carbon atoms, preferably 4 to 10 carbon atoms.
Α-olefins such as 1-butene, 1-pentene,
4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene and the like. The polypropylene resin (C-1) that has not been thermally degraded is propylene / α described later.
-It may be the same as or different from the olefin random copolymer (D-1).

The ethylene content of the polypropylene resin (C-1) is desirably 2 to 4% by weight, preferably 3 to 4% by weight, and more preferably 3.5 to 4% by weight. The content of α-olefins other than propylene and ethylene in the polypropylene resin (C-1) is 0 to 2% by weight, preferably 0 to 1.5% by weight, and more preferably 0 to 0.5% by weight.
Desirably, it is% by weight.

The melt flow rate (MFR (230) of the polypropylene resin (C-1) not thermally degraded
C) is 2 to 20 g / 10 min, preferably 4 to 15 g / min.
It is preferably 10 minutes, more preferably 8 to 15 g / 10 minutes. Mw / Mn of the polypropylene resin (C-1) that has not been thermally degraded is 3.8 to 5.5, preferably 4.0 to 5.0, and more preferably 4.2 to 4.8. desirable.

The thermally degraded polypropylene resin (C-
2) is preferably obtained by thermally degrading a mixture containing a propylene / α-olefin random copolymer (D-1) and a propylene homopolymer (D-2).

The propylene / α-olefin random copolymer (D-1) is a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms, preferably 4 to 10 carbon atoms (excluding propylene), A propylene / ethylene random copolymer is preferred. Examples of the α-olefin other than propylene include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene,
Heptene, 1-octene, 1-decene, 1-dodecene,
1-hexadecene and the like. Of these, ethylene is preferred.

The ethylene content of the propylene / α-olefin random copolymer (D-1) is 2 to 5% by weight, preferably 3 to 4.5% by weight, more preferably 3.5 to 4% by weight.
Desirably, it is% by weight. The content of α-olefins other than propylene and ethylene in the propylene / α-olefin random copolymer (D-1) is 0 to 2% by weight, preferably 0 to 1.5% by weight, and more preferably 0 to 0.
Desirably, it is 5% by weight.

The propylene / α-olefin random copolymer (D-1) has a melt flow rate (MFR (230
C) is 2 to 20 g / 10 min, preferably 4 to 15 g / min.
It is preferably 10 minutes, more preferably 8 to 15 g / 10 minutes.

The propylene homopolymer (D-2) has a melt flow rate (MFR (230 ° C.)) of 2 to 20 g / g.
It is desirably 10 minutes, preferably 4 to 15 g / 10 minutes, and more preferably 8 to 15 g / 10 minutes.

The mixing ratio of the propylene / α-olefin random copolymer (D-1) to the propylene homopolymer (D-2) is 99 to 100% for the propylene / α-olefin random copolymer (D-1). 70% by weight, preferably 95 to
80% by weight, more preferably 90 to 85% by weight, the propylene homopolymer (D-2) is 1 to 30% by weight, preferably 5 to 20% by weight, more preferably 10 to 15% by weight. . When the mixing ratio of both is in the above range, a polypropylene resin composition having an excellent balance between rigidity and transparency can be obtained.

Non-thermally degraded polypropylene resin (C-1), propylene / α-olefin random copolymer (D-1) and propylene homopolymer (D-2)
Can be produced by a known method. For example, a transition metal compound component such as a titanium-based or zirconium-based component, an organoaluminum component, an electron donor as needed,
In the presence of a stereoregular olefin polymerization catalyst containing a carrier and the like, propylene and, if necessary, ethylene and other α-
It can be produced by polymerizing an olefin.

In the present invention, thermal degradation of the polypropylene resin can be performed by a known method. For example, the following method is exemplified. First, a polypropylene resin, an organic peroxide, and other additives added as necessary are mixed. The mixing can be performed by a mixing device such as a ribbon blender, a tumbler blender, and a Henschel blender. Next, the mixture is melt-kneaded to obtain a thermally degraded polypropylene resin. Examples of melt-kneading devices include kneaders such as co-kneaders, Banbury mixers, Brabenders, single-screw extruders, and twin-screw extruders; biaxial surface updaters; horizontal-type stirrers such as twin-screw multi-disk devices; Vertical stirrer or the like can be employed.

The heating temperature during the melt-kneading is from 170 to 250.
C, preferably 180 to 220C.
When melt kneading in this temperature range, the polypropylene resin is sufficiently melted, and the organic peroxide is completely decomposed,
The obtained polypropylene resin composition is preferable since it does not change its properties during molding. The time for melt kneading is generally 10 seconds to 5 minutes, preferably 30 seconds to 6 minutes.
It is desirably 0 seconds.

In the present invention, known organic peroxides can be used as the organic peroxide used for the thermal degradation treatment of the polypropylene resin. Preferred organic peroxides include, for example, ketone peroxides such as methyl ethyl ketone peroxide and methyl acetoacetate peroxide; 1,1-bis (t-butylperoxy) -3,
3,5-trimethylcyclohexane, 1,1-bis (t
-Butylperoxy) cyclohexane, n-butyl-
4,4-bis (t-butylperoxy) valerate,
Peroxyketals such as 2,2-bis (t-butylperoxy) butane; permethane hydroperoxide,
Hydroperoxides such as 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide; dicumyl peroxide, 2,5-dimethyl-2,5-di (t
-Butylperoxy) hexane, α, α'-bis (t-
Dialkyl peroxides such as butylperoxy m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexine-3; benzoyl peroxide and the like Diacyl peroxide; t
-Butyl peroxy octate, t-butyl peroxyisobutyrate, t-butyl peroxy laurate, t
-Butylperoxy 3,5,5-trimethylhexanoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t
And peroxyesters such as -butylperoxybenzoate and di-t-butylperoxyisophthalate. Of these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 is preferred. The organic peroxides can be used alone or in combination of two or more.

The amount of the organic peroxide to be added is preferably 0.001 to 0.5 part by weight, more preferably 0.005 to 0.2 part by weight, based on 100 parts by weight of the polypropylene resin. When the addition amount of the organic peroxide is in the above range, a modifying effect of narrowing the molecular weight distribution can be obtained without lowering physical properties such as melt tension, and the fluidity can be improved. .

The particularly preferred polypropylene resin (A) in the present invention is a polypropylene resin obtained by the following thermal degradation.

[Outside 1]

In a preferred embodiment of the present invention, a propylene / α-olefin random copolymer (D-1) and a propylene homopolymer (D-2) are first mixed to obtain a mixture. In this case, the mixing ratio of the propylene / α-olefin random copolymer (D-1) and the propylene homopolymer (D-2) is 99 to 100% for the propylene / α-olefin random copolymer (D-1). 70% by weight, preferably 95
To 80% by weight, more preferably 90 to 85% by weight, and the propylene homopolymer (D-2) is 1 to 30% by weight, preferably 5 to 20% by weight, more preferably 10 to 15% by weight. desirable. When the mixing ratio of both is in the above range, a polypropylene resin composition having an excellent balance between rigidity and transparency can be obtained.

Next, the propylene / α-olefin random copolymer (D-1) and the propylene homopolymer (D
-2) is thermally degraded in the presence of an organic peroxide to produce a thermally degraded polypropylene resin (C-2). In this case, the added amount of the organic peroxide is propylene.
0.001 to 0.5 part by weight, preferably 0.1 to 0.5 part by weight, based on 100 parts by weight of the α-olefin random copolymer (D-1).
It is preferably from 005 to 0.2 parts by weight. When the addition amount of the organic peroxide is in the above range, a modifying effect of narrowing the molecular weight distribution can be obtained without lowering physical properties such as melt tension, and the fluidity can be improved. .

The propylene / α-olefin random copolymer (D-1), the propylene homopolymer (D-2), the organic peroxide and other optional additives are melt-kneaded after mixing. Is preferred. The mixing can be performed by a mixing device such as a ribbon blender, a tumbler blender, and a Henschel blender. Then, by melt-kneading, the thermally degraded polypropylene resin (C-
2) can be obtained. Examples of melt-kneading devices include kneaders such as co-kneaders, Banbury mixers, Brabenders, single-screw extruders, and twin-screw extruders; biaxial surface updaters; horizontal-type stirrers such as twin-screw multi-disk devices; Vertical stirrer or the like can be employed.

The heating temperature during melt kneading is 170 to 250.
C, preferably 180 to 220C.
When melt-kneaded in this temperature range, the propylene / α-olefin random copolymer (D-1) is sufficiently melted, and the organic peroxide is completely decomposed. This is preferable because it does not change. The time for melt-kneading is generally from 10 seconds to 15 minutes, preferably from 30 seconds to 10 minutes.

In a preferred embodiment of the present invention, the thermally degraded polypropylene resin (C-
2) and non-thermally degraded polypropylene resin (C-
1) to produce a polypropylene resin (C). The blending ratio of the thermally degraded polypropylene resin (C-2) and the non-thermally degraded polypropylene resin (C-1) is determined according to the non-thermally degraded polypropylene resin (C-
1) is 98 to 70% by weight, preferably 95 to 80% by weight, more preferably 93 to 85% by weight, and the thermally degraded polypropylene resin (C-2) is 2 to 30% by weight, preferably 5 to 20% by weight. %, More preferably 7 to 15% by weight.

The polypropylene resin (C) obtained by the above method is then subjected to a thermal degradation treatment by blending an organic peroxide to produce a polypropylene resin composition (A). The conditions of this thermal degradation treatment and the compounding amount of the organic peroxide can be carried out under the same conditions as those described for the production of the thermally degraded polypropylene resin (C-2).

According to a preferred embodiment of the present invention, the propylene homopolymer (D-2) is sufficiently dispersed and present in the polypropylene resin composition (A) to improve transparency and rigidity. I do. In addition, it is possible to obtain a polypropylene resin having a molecular weight distribution within a specific range and free of a high molecular weight substance which causes early crystallization.

<< Nucleating Agent (B) >> As the nucleating agent (B) used in the present invention, known nucleating agents can be used without any limitation, but organic phosphoric acid ester compounds, sorbitol compounds, C ₄ -C ₁₂
And a nucleating agent selected from the group consisting of aliphatic dicarboxylic acids or metal salts thereof, aromatic carboxylic acids or metal salts thereof, and chlorine rosinate compounds, and among them, organophosphate compounds are preferable.

As the organic phosphate compound used as the nucleating agent (B), known organic phosphate compounds can be used, but the compounds represented by the above formula (1) or (2) are preferred. In the formulas (1) and (2), the divalent carbon atoms having 1 to 10 represented by R ¹ include a methylene group,
Examples include an ethylidene group, a butylidene group, and a t-octylmethylene group. Among these, a methylene group or an ethylidene group having 1 or 2 carbon atoms is preferable.

R ² and R ^{3 in the} above formulas (1) and (2)
Represents a methyl group, an ethyl group, i-
Examples thereof include a propyl group, an n-butyl group and a t-butyl group. Among them, a methyl group or an ethyl group having 1 or 2 carbon atoms is preferable. R in the above formulas (1) and (2)
Preferably, ² and R ³ are both hydrocarbon groups.

The metal atom represented by M in the above formulas (1) and (2) includes lithium, sodium, potassium,
Examples include magnesium, calcium, barium, and aluminum. In the above formulas (1) and (2), n
Is an integer of 1 to 3, preferably 1. m is 1 or 2, preferably 1.

Specific examples of the organophosphate compound represented by the above formula (1) include sodium-2,2'-methylene-bis (4,6-di-t-butylphenyl) phosphate, sodium -2,2'-ethylidene-bis (4,6-di-t-butylphenyl) phosphate,
Lithium-2,2'-methylene-bis- (4,6-di-
t-butylphenyl) phosphate, lithium-2,
2'-ethylidene-bis (4,6-di-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis (4-i-propyl-6-t-butylphenyl) phosphate, Lithium-2,2'-methylene-
Bis (4-methyl-6-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis (4-ethyl-6-t-butylphenyl) phosphate, sodium-2,2'- Butylidene-bis (4,6-dimethylphenyl) phosphate, sodium-2,2'-
Butylidene-bis (4,6-di-t-butylphenyl)
Phosphate, sodium-2,2'-t-octylmethylene-bis (4,6-dimethylphenyl) phosphate, sodium-2,2'-t-octylmethylene-bis (4,6-di-t -Butylphenyl) phosphate, calcium-bis- (2,2'-methylene-bis (4,6-di-t-butylphenyl) phosphate)
G), magnesium-bis [2,2′-methylene-bis (4,6-di-t-butylphenyl) phospho-
G], barium-bis [2,2'-methylene-bis (4,6-di-t-butylphenyl) phospho-
G], sodium-2,2'-methylene-bis (4-methyl-6-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis (4-ethyl-6
t-butylphenyl) phosphate, sodium
2,2'-ethylidene-bis (4-n-butyl-6-t
-Butylphenyl) phosphate, sodium-2,
2'-methylene-bis (4,6-dimethylphenyl) phosphate, sodium-2,2'-methylene-bis (4,6-diethylphenyl) phosphate, potassium-2,2'-ethylidene -Bis (4,6-di-t-
Butylphenyl) phosphate, calcium-bis [2,2'-ethylidene-bis (4,6-di-t-butylphenyl) phosphate], magnesium-bis [2,2'-ethylidene-bis (4 , 6-Di-tert-butylphenyl) phosphate], barium-bis [2,
2′-ethylidene-bis (4,6-di-tert-butylphenyl) phosphate], aluminum-tris [2,
2'-methylene-bis (4,6-di-t-butylfell) phosphate] and aluminum-tris [2,2'-ethylidene-bis (4,6-di-t-butylphenyl) phosphate] And so on. These can be used alone or in combination of two or more.

A hydroxyaluminum phosphate compound represented by the above formula (2) is also a usable organic phosphoric acid ester compound. Particularly, in the following formula (3) wherein both R ² and R ³ are t-butyl groups. The compounds represented are preferred.

Embedded image (In the formula (3), R ¹ and m are the same as those in the formula (2). Bu is a butyl group.)

Particularly preferred organic phosphate compound used as the nucleating agent (B) is a compound represented by the following formula (4).

Embedded image (In the formula (4), R ¹ is a methylene group or an ethylidene group. Bu is a butyl group.)

The organic phosphoric ester compound represented by the above formula (4) is specifically exemplified by hydroxyaluminum-bis [2,2-methylene-bis (4,6-di-t-butylphenyl) phosphate]. Or hydroxyaluminum-bis [2,2-ethylidene-bis (4,6-di-
t-butylphenyl) phosphate].

The sorbitol compounds used as the nucleating agent (B) include 1,3,2,4-dibenzylidene sorbitol, 1,3-benzylidene-2,4-p-methylbenzylidene sorbitol, 1,3-benzylidene −
2,4-p-ethylbenzylidene sorbitol, 1,3
-P-methylbenzylidene-2,4-benzylidenesorbitol, 1,3-p-ethylbenzylidene-2,4-
Benzylidene sorbitol, 1,3-p-methyl benzylidene-2,4-p-ethyl benzylidene sorbitol, 1,3-p-ethyl benzylidene-2,4-p-methyl benzylidene sorbitol, 1,3,2,4-di (P-methylbenzylidene) sorbitol, 1,3
2,4-di (p-ethylbenzylidene) sorbitol,
1,3,2,4-di (pn-propylbenzylidene)
Sorbitol, 1,3,2,4-di (pi-propylbenzylidene) sorbitol, 1,3,2,4-di (p
-N-butylbenzylidene) sorbitol, 1,3,
2,4-di (ps-butylbenzylidene) sorbitol, 1,3,2,4-di (pt-butylbenzylidene) sorbitol, 1,3,2,4-di (p-methoxybenzylidene) sorbitol , 1,3,2,4-di (p
-Ethoxybenzylidene) sorbitol, 1,3-benzylidene-2,4-p-chlorobenzylidenesorbitol, 1,3-p-chlorobenzylidene-2,4-benzylidenesorbitol, 1,3-p-chlorobenzylidene-2,4 -P-methylbenzylidene sorbitol, 1,
3-p-chlorobenzylidene-2,4-p-ethylbenzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-p-chlorobenzylidene sorbitol,
Examples thereof include 1,3-p-ethylbenzylidene-2,4-p-chlorobenzylidene sorbitol and 1,3,2,4-di (p-chlorobenzylidene) sorbitol. These can be used alone or in combination of two or more. Examples of the organic peroxide include 1,3,2,4-dibenzylidenesorbitol, 1,3,2,4-di (p-methylbenzylidene) sorbitol and 1,3-p-chlorobenzylidene-2,4-p- Methylbenzylidene sorbitol is preferred.

The C ₄ -C ₁₂ aliphatic dicarboxylic acids or metal salts thereof used as the nucleating agent (B) include succinic acid, glutaric acid, adipic acid, suberic acid and sebacic acid, and their Li, Na , Mg, Ca,
Ba or Al salts may, for example, be mentioned.

The aromatic carboxylic acids or metal salts thereof used as the nucleating agent (B) include benzoic acid, allyl-substituted acetic acid, aromatic dicarboxylic acids and their elements belonging to Groups I, II and III of the periodic table. Metal salts, specifically, benzoic acid, p-isopropylbenzoic acid, o-tert.
Butyl benzoic acid, p-tert-butyl benzoic acid, monophenylacetic acid, diphenylacetic acid, phenyldimethylacetic acid and phthalic acid, and their Li, Na, Mg, C
a, Ba or Al salts. The nucleating agent (B) can be used alone or in combination of two or more.

<< Polypropylene Resin Composition >> The polypropylene resin composition of the present invention contains 0.05 to 50 parts by weight of the nucleating agent (B) per 100 parts by weight of the polypropylene resin (A).
It is a polypropylene resin composition containing 0.5 parts by weight, preferably 0.2 to 0.3 parts by weight.

In the polypropylene resin composition of the present invention, in addition to the polypropylene resin (A) and the nucleating agent (B), if necessary, an antioxidant, a heat stabilizer, an antistatic agent, a weather stabilizer, Other additives such as a light stabilizer, a dispersant, a coloring agent, and a lubricant may be blended as long as the object of the present invention is not impaired.

Examples of the antioxidant that can be added to the polypropylene resin composition of the present invention include a phosphorus antioxidant and / or an amine antioxidant. There is no particular limitation on the phosphorus antioxidant,
Known phosphorus antioxidants can be used. In addition,
It is preferable to use only one type of phosphorus-based antioxidant, because the contamination of the contents by bleed is small.

The phosphorus antioxidant preferably used in the present invention is a trivalent organic phosphorus compound, specifically, tris (2,4-di-t-butylphenyl) phosphite,
2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (2,6-di-tert-butyl)
Butyl-4-methylphenyl) pentaerythritol diphosphite. The phosphorus-based antioxidant is usually used in an amount of 0.05 to 0.3 part by weight, preferably 0.1 to 0.3 part by weight based on 100 parts by weight of the polypropylene resin (A).
It is desirable to use 0.3 parts by weight, more preferably 0.1 to 0.2 parts by weight.

The amine-based antioxidant is not particularly limited, and a known amine-based antioxidant can be used. Examples of the amine antioxidant that can be preferably used in the present invention include compounds having a piperidine ring. Specifically, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, bis (2,2,6,6-
(Tetramethyl-4-piperidyl) sebacate. The amine-based antioxidant is used in an amount of usually 0.01 to 0.2 part by weight, preferably 0.01 to 0.1 part by weight, more preferably 0.05 to 0.1 part by weight based on 100 parts by weight of the polypropylene resin (A). It is desirable to use 1 part by weight.

The polypropylene resin composition of the present invention comprises the above-mentioned polypropylene resin (A), nucleating agent (B), and if necessary, other additives, etc.
After mixing using a mold blender, tumbler blender, ribbon blender, etc., a single-screw extruder, multi-screw extruder,
It can be produced by melt-kneading using a kneader, a Banbury mixer or the like. When a thermally degraded polypropylene resin is used as the polypropylene resin (A), a nucleating agent (B) is blended in the mixture to be thermally degraded, and the thermal degradation and the production of the resin composition are performed. It can be done at the same time. By producing in this manner, a high-quality polypropylene resin composition in which each component and additive are uniformly dispersed and mixed can be obtained.

A method for producing a particularly preferred polypropylene resin composition in the present invention will be described below.

[Outside 2]

In a preferred embodiment of the present invention, first, a propylene / α-olefin random copolymer (D-1), a propylene homopolymer (D-2) and a nucleating agent (B) are mixed to obtain a mixture. . In this case, the compounding ratio of the nucleating agent (B) is determined according to the propylene / α-olefin random copolymer (D
-1) and a total of 1 of propylene homopolymer (D-2)
It is desirably 0.05 to 0.45 parts by weight, preferably 0.2 to 0.3 parts by weight, per 100 parts by weight. next,
The mixture is thermally degraded in the presence of an organic peroxide, and a thermally degraded polypropylene resin (C-
2) is manufactured.

Next, the thermally degraded polypropylene resin (C-C) containing the nucleating agent (B) obtained by thermal degradation as described above.
2) and non-thermally degraded polypropylene resin (C-
1) to produce a polypropylene resin (C). Further, the polypropylene resin (C) and the nucleating agent (B) are mixed, and a thermal degradation treatment is performed in the presence of an organic peroxide. The mixing ratio of the nucleating agent (B) in this case is 0.05 to 100 parts by weight of the polypropylene resin (C).
It is desirably 0.45 parts by weight, preferably 0.2 to 0.3 parts by weight. Thus, the polypropylene resin composition (A) containing the nucleating agent (B) is produced, and the polypropylene resin composition of the present invention is produced. The method and conditions for thermal degradation are the same as in the preferred embodiment of the polypropylene resin composition (A).

The polypropylene resin composition of the present invention is excellent in injection stretch blow moldability, excellent in rigidity, gloss, transparency, flexibility and impact resistance, and has a balance among them. Further, the polypropylene resin composition of the present invention can provide a container having excellent squeezing properties.

<< Container >> The container of the present invention is a container comprising the polypropylene resin composition of the present invention. The shape and size of the container are not particularly limited and are arbitrary. The production method is not particularly limited, either, but it is preferable to produce by an injection stretch blow molding method. The container of the present invention is excellent in rigidity, gloss, transparency, flexibility, squeezability and impact resistance and is well balanced. The container of the present invention is a container or packaging for various foods, detergents, medical products, etc .;
It can be suitably used as a medical container or the like.

<< Method of Manufacturing Container >> In the method of manufacturing the container of the present invention, the polypropylene resin composition of the present invention is injection-molded to form a preform, and then the preform is stretch blow-molded to manufacture the container. This is a stretch blow molding method using a so-called hot parison method. In the method for producing a container of the present invention, first, a preform is injection-molded using the polypropylene resin composition of the present invention. Next, the preform is stretch-blown using both a stretching rod and compressed air to obtain a container shape. Before performing stretch blow, compressed air may be blown (pre-blown) into the preform and stretched to form a preblown preform.

Here, the stretching ratio and the blowing pressure for pre-blow and stretching blow depend on the final container shape, the molding machine, the polypropylene resin composition to be used, etc., but the preliminary blow ratio is 1 to 2.0 times in the longitudinal direction. It is desirable to stretch the film in the transverse direction by a factor of 1 to 2.2. The stretch blow ratio is desirably 1.0 to 4.0 times in the longitudinal direction.
The preliminary blow pressure is 0.01 to 0.1 MPa (1 to 0.1 MPa).
10 kgf / cm ² ).
A pressure setting of 0.4 MPa ( ^{2 to} 40 kgf / cm ² ) is desirable. The shape of the preform is generally a test tube type, but the shape is not limited, and is not limited to a preform shape such as a disk shape or a conical shape.

[0067]

The polypropylene resin composition of the present invention has
Since it contains a specific amount of polypropylene resin and nucleating agent having specific physical properties, it is excellent in injection stretch blow moldability, and rigidity, gloss, transparency, flexibility and impact resistance are simultaneously improved in a well-balanced manner. In addition, a container having excellent squeezing properties can be obtained. Since the container of the present invention is obtained from the polypropylene resin composition, rigidity, gloss, transparency, flexibility, and impact resistance are improved at the same time in a well-balanced manner, and the squeezing property is excellent.
And it can be easily and efficiently manufactured by injection stretch blow molding. Since the method for producing a container of the present invention uses the polypropylene resin composition to form a preform by injection molding and then stretch-blow-molds the preform, the container is easily and efficiently produced. can do.

[0068]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below by way of examples, but the present invention is not limited to these examples.

The raw materials used in the examples are as follows. -(PP-1) propylene / ethylene random copolymer: MFR (230 ° C); 11 g / 10 min Mw / Mn; 4.2 Ethylene content: 4.0% by weight ・ (PP-2) propylene / ethylene random Copolymer: MFR (230 ° C.); 8 g / 10 minutes Ethylene content: 2.6% by weight ・ (PP-3) Propylene homopolymer: MFR (230 ° C.): 8 g / 10 minutes Measured by ¹³ C-NMR Isotactic pentad fraction obtained: 0.963 · (PP-4) propylene / ethylene random copolymer: MFR (230 ° C); 40 g / 10 min Mw / Mn; 4.4

(B-1) Nucleating agent: hydroxyaluminum-bis [2,2-methylene-bis (4,6-di-t-butylphenyl) phosphate represented by the above formula (4)] -Phosphorus antioxidant: tris (2,4-di-t-butylphenyl) phosphite

In the present invention, physical properties were measured by the following methods. Mw / Mn: determined from GPC. The measurement conditions of GPC are as follows. Apparatus; Waters, 150CV-plus (trademark) Column; Shodex GPC AD-80M / S (Showa Denko KK, trade name) Column size (inner diameter x length); 8 mm x 250 mm Exclusion limit molecular weight (PEG); 2 × 10 ⁷ separation range; 500 to 20,000,000 filler; styrene-divinylbenzene copolymer mobile phase; o-dichlorobenzene flow rate; 1.0 ml / min sample concentration; 0.2 w / v% injection amount; 0.2 ml detector; differential refractometer measurement temperature; 135 ° C

Melt flow rate (MFR): AST
According to MD 1238, load 2.16 kg, 230
It was measured under the condition of ° C. -Tensile yield strength and elongation at break: ASTM D6
A bending test was carried out in accordance with No. 38, and the tensile yield strength and elongation at break were measured from the results. Bending modulus: A bending test was performed in accordance with ASTM D790, and the bending modulus was calculated from the results.

High-speed surface impact test (high-speed surface impact absorption energy): At 23 ° C., at a speed of 3 m / s, the tip diameter 1 /
A striker with a 2-inch load cell is caused to collide with a 2 mm-thick square test piece. On the back surface of the test piece, a table having a tip diameter (receiving diameter) of 3 inches was used as a receiving table. As values, the total absorbed energy and the ductile energy from breakdown to fracture were determined, respectively. Haze: Measured on a test piece cut out from a 2 mm sheet or container in accordance with ASTM D 1003.

Container squeezability (flexibility): The center of a cylindrical container (200 ml) was crushed from the left and right, and the inner walls of the container were brought into contact with each other. In this state, the force was released, and it was observed whether or not the container recovered to the shape before crushing and whether or not whitening occurred. A: The shape before crushing was not recovered, and no whitening was observed in the crushed portion. I can't tell where I bend it even if I put it back by external force. ；: The shape before the crushing was not recovered, and no whitening was observed at the crushed portion. If you apply force from the outside to restore it, the bent part will be damaged. ×: Recovered to the shape before crushing without applying external force. -Fall strength of container: A cylindrical container (200 ml) was covered with a metal stopper, filled with water at 5 ° C, dropped from a height of 1 m, and checked for damage to the container. The same test was performed on 20 containers.

Example 1 100 parts by weight of a resin mixture containing 87.5% by weight of a propylene / ethylene random copolymer (PP-2) and 12.5% by weight of a propylene homopolymer (PP-3) in a Henschel mixer And 0.05 parts by weight of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as an organic peroxide, and hydroxyaluminum-bis [2,2-methylene- as a nucleating agent. Screw (4
6-di-t-butylphenyl) phosphate].
2 parts by weight, 0.1 part by weight of tris (2,4-di-t-butylphenyl) phosphite as a phosphorus-based antioxidant, 0.1 part by weight of calcium stearate, 0.1 part by weight of erucamide , And 0.25 parts by weight of ADK STAB NA-21 (trade name, manufactured by Asahi Denka Co., Ltd.) as a transparent seed agent were added, followed by stirring and mixing. Next, the mixture was melt-kneaded at a resin temperature of 230 ° C. using a twin-screw extruder (40 mmφ) and thermally degraded, and then the kneaded product was extruded to obtain pellets of a polypropylene resin composition (PPC-1).

Next, 10 parts by weight of the above-mentioned polypropylene resin composition (PPC-1) pellets and a propylene / ethylene random copolymer (PP-
1) 90 parts by weight, 0.25 parts by weight of the same nucleating agent as described above, 0.03 parts by weight of the same organic peroxide as described above, 0.05 parts by weight of the same phosphorus-based antioxidant as described above, and 0.1 part by weight of calcium stearate. 07 parts by weight were added and mixed by stirring. Next, the mixture was melt-kneaded at a resin temperature of 230 ° C. using the same twin-screw extruder as described above, and thermally degraded.

Next, the pellets of the above polypropylene resin composition (PPC-2) were injection-molded into 18
A sheet test piece having a thickness of 2 mm and a test piece for bending strength test (ASTM D 79) at 0 ° C. and a mold temperature of 40 ° C.
0, thickness 3.2mm, length 127mm, width 12.7m
m), and a test piece (ASTM D 638, length 115 mm, thickness 3.2 mm, width 19/6 mm) for a tensile test was prepared. Using these test pieces, haze, flexural modulus and the like were measured by the method described above. Table 1 shows the results.

Also, a hot parison injection blow molding machine (AOKI TECHNICAL LABORATORY INC: SBIII250S-50)
Using the above-mentioned polypropylene resin composition (PPC-
2) As a raw material, a 200 ml container (having a height of 11
cm / diameter 8 cm). The physical properties were measured by the above method using the obtained container. Table 1 shows the results. Injection temperature: 180 ° C Injection time: 4 seconds Mold temperature: 13 ° C Cooling time: 4 seconds Blow pressure: 1.3 MPa Stretching ratio: 2 × 2 × 2

The propylene / ethylene random copolymer (PP-2) and the propylene homopolymer (PP-
3), propylene / ethylene random copolymer (PP-
Using only the organic peroxide 1) and the organic peroxide, the physical properties of the polypropylene resin obtained by thermal degradation in the same manner as in the method for producing the polypropylene resin composition (PPC-2) were measured. 10 minutes, Mw / Mn is 2.
7. The ethylene content was 3.8% by weight.

Comparative Example 1 In Example 1, propylene homopolymer (PP-3)
And a propylene / ethylene random copolymer (PP-
A propylene / ethylene random copolymer (PP-4) was used in place of 2), and the additives were used in the same manner as in Example 1 without thermal degradation. Table 1 shows the results.

Comparative Example 2 In Example 1, the polypropylene resin composition (PPC
-1) A polypropylene resin composition (ppc-1) having a melt flow rate of 100 g / 10 min in the same manner as in Example 1 except that the amount of the organic peroxide used together with -1) was changed to 0.05 part by weight. Obtained. Except using this polypropylene resin composition (ppc-1), it carried out similarly to Example 1. Table 1 shows the results.

[0082]

[Table 1]

As can be seen from the results in Table 1, the polypropylene resin composition of the present invention is excellent in rigidity, transparency, flexibility and impact resistance. Further, a container molded from this resin composition is excellent in transparency and squeezability, and is flexible and excellent in drop impact. As described above, it has excellent physical properties not found in conventional polypropylene resin compositions and is very useful.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 5/00 CES C08K 5/09 C08K 5/09 5/521 5/521 C08L 93/04 C08L 93/04 B29K 23:00 // B29K 23:00 B29L 22:00 B29L 22:00 B65D 1/00 ACF term (reference) 3E033 BA16 BB01 CA03 CA06 CA18 FA03 4F071 AA15 AA15X AA20 AA20X AA21 AA21X AA74 AC05 AC05 AC05 BA05 BB05 BB07 BC04 4F208 AA11H AA11K AB08 AG07 AH55 LA02 LA04 LB01 LG28 4J002 AF022 BB121 BB141 BB151 BB201 BP021 BP031 EC056 EF026 EF056 EF096 HCEGA EG046 EG046 EW046 FD202 FD206 4J100 AAQAQA4A

Claims (16)

[Claims] 1. A melt flow rate (ASTM)
D 1238, 230 ° C, 2.16 kg load) 20 to
60 g / 10 min, molecular weight distribution (Mw / Mn) determined by gel permeation chromatography is 2.2
(B) A polypropylene resin composition containing 0.05 to 0.5 parts by weight of a nucleating agent with respect to 100 parts by weight of a polypropylene resin having an ethylene content of 2 to 4% by weight. 2. The polypropylene resin (A) has an α-olefin content other than propylene and ethylene of from 0 to 2 inclusive.
The polypropylene resin composition according to claim 1, which is in a percentage by weight. 3. The polypropylene resin (A) according to claim 1, wherein the polypropylene resin (A) is a polypropylene resin obtained by thermal degradation.
The polypropylene resin composition according to the above. 4. The polypropylene resin composition according to claim 1, wherein the polypropylene resin (A) contains a thermally degraded polypropylene resin two or more times. 5. The method according to claim 1, wherein the polypropylene resin (A) is obtained by thermal degradation by melt-kneading the polypropylene resin (C) in the presence of an organic peroxide. The polypropylene resin composition according to the above. 6. The polypropylene resin composition according to claim 5, wherein the polypropylene resin (C) contains a thermally degraded polypropylene resin (C-1) and a thermally degraded polypropylene resin (C-2). . 7. A polypropylene resin (C) in which the polypropylene resin (C) is not thermally degraded (80% to 98% by weight) and a thermally degraded polypropylene resin (C-2) (2 to 2%).
7. The polypropylene resin composition according to claim 5, comprising 0% by weight. 8. The polypropylene resin composition according to claim 6, wherein the non-thermally degraded polypropylene resin (C-1) is a propylene / α-olefin random copolymer. 9. The polypropylene resin composition according to claim 6, wherein the non-thermally degraded polypropylene resin (C-1) is a propylene / ethylene random copolymer. 10. A thermally degraded polypropylene resin (C)
-2) is obtained by thermally degrading a mixture containing a propylene / α-olefin random copolymer (D-1) and a propylene homopolymer (D-2). The polypropylene resin composition according to any one of the above. 11. A thermally degraded polypropylene resin (C)
-2) is obtained by thermally degrading a mixture containing 80 to 98% by weight of a propylene / α-olefin random copolymer (D-1) and 2 to 20% by weight of a propylene homopolymer (D-2). The polypropylene resin composition according to any one of claims 6 to 10, wherein 12. The polypropylene resin composition according to claim 10, wherein the propylene / α-olefin random copolymer (D-1) is a propylene / ethylene random copolymer. 13. The nucleating agent (B) is an organic phosphate compound, a sorbitol compound, a C _{4 to} C ₁₂ aliphatic dicarboxylic acid or a metal salt thereof, an aromatic carboxylic acid or a metal salt thereof, and a chlorine rosinate compound. The polypropylene resin composition according to any one of claims 1 to 12, which is at least one member selected from the group consisting of: 14. The organic phosphate compound is a compound represented by the following formula (1) or (2).
The polypropylene resin composition according to the above. Embedded image (In the formula (1) or (2), R ¹ is a group having 1 to 10 carbon atoms.
A divalent hydrocarbon group, R ² and R ³ are hydrogen or C 1 -C
10 hydrocarbon groups. R ² and R ³ may be the same or different. M is a metal atom having 1 to 3 valences, and n is 1
-3. m is 1 or 2. ) 15. A container comprising the polypropylene resin composition according to claim 1. 16. A method for producing a container, comprising: forming a preform by injection molding the polypropylene resin composition according to claim 1; and then stretching and blowing the preform to produce a container.