JP7126601B2 - Propylene-based resin composition and molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a propylene-based resin composition and a molded article, typified by a container, formed from the composition.

BACKGROUND ART Propylene-based resin compositions, which are excellent in heat resistance, rigidity and transparency, are often used as raw materials for packaging containers for foods such as jelly, pudding, and coffee (hereinafter also referred to as food packaging containers). In addition, food is often handled in a low-temperature environment during storage and distribution, so food packaging containers are required to have not only impact resistance at room temperature, but also impact resistance at low temperatures, that is, low-temperature impact resistance. be done.

As a propylene-based resin composition having excellent impact resistance, a composition containing a propylene-ethylene block copolymer, a nucleating agent, and a low-density polyethylene resin or a linear low-density polyethylene resin is known (for example, patent Document 1), as a propylene-based resin composition excellent in low-temperature impact resistance, a composition comprising a propylene block copolymer and an ethylene-based resin and having specific physical properties is known (for example, Patent Document 2, 3).

Patent Document 4 discloses a polypropylene-based resin composition containing a crystalline propylene-ethylene block copolymer having a specific resin structure, a crystalline polypropylene-based resin, a high-density polyethylene, and optionally an elastomer. It is described that a sheet or film having an excellent balance of resistance to whitening, rigidity, and low-temperature impact resistance can be obtained from the composition, and that this composition is useful for applications such as food containers.

Furthermore, Patent Document 5 discloses a propylene-based resin composition containing a specific propylene-based random block copolymer, from which an injection-molded article having excellent impact resistance and the like can be obtained. It is described that it can be used for containers and the like, and furthermore, it is described that a polyethylene resin may be added to this composition in order to impart functions such as impact resistance.

Further, in recent years, from the viewpoint of reducing environmental load, cost, etc., these containers are required to be thinner and lighter.
In order to meet these demands, Patent Document 6 discloses a food product containing a specific propylene-based block copolymer, a specific ethylene/α-olefin copolymer produced using a single-site catalyst, and a nucleating agent. Proposal of a propylene-based resin composition that is excellent in rigidity, low-temperature impact resistance, and transparency even when it is made thinner and lighter than before when manufacturing molded articles such as containers such as packaging containers. It is

Japanese Patent Application Laid-Open No. 2001-26686 JP-A-2002-187996 JP-A-2002-187997 JP-A-2005-26981 WO2007/116709 WO2010/074001

However, food packaging containers formed from conventional propylene-based resin compositions have room for further improvement from the viewpoint of high-speed moldability of thin-walled molded products, rigidity, and low-temperature impact resistance.
Accordingly, the present invention provides a propylene-based resin composition which is excellent in high-speed moldability even when producing thin-walled molded articles, and which enables the production of molded articles which are excellent in well-balanced rigidity and low-temperature impact resistance. With the goal.

The gist of the present invention is as follows.
[1]
75 to 92 parts by mass of a propylene polymer (A) satisfying the following requirements (A1) to (A5);
8 to 25 parts by mass of an ethylene polymer (B) that satisfies the following requirements (B1) to (B2) (provided that the total amount of the propylene polymer (A) and the ethylene polymer (B) is 100 parts by mass) ), and a propylene-based resin composition containing 0.02 to 1.0 parts by mass of a nucleating agent (C).
(A1): According to ASTM D-1238, the melt flow rate measured at a measurement temperature of 230°C and a load of 2.16 kg is 45 to 195 g/10 minutes.
(A2): Contains 80 to 92% by mass of a portion insoluble in room temperature n-decane and 8 to 20% by mass of a portion soluble in room temperature n-decane.
(A3): The proportion of ethylene-derived structural units in the portion insoluble in n-decane at room temperature is 0 to 1.0% by mass.
(A4): The proportion of ethylene-derived structural units in the portion soluble in room temperature n-decane is 25 to 35% by mass.
(A5): The intrinsic viscosity [η] of the portion soluble in room temperature n-decane in decalin at 135° C. is 1.0 to 3.0 dl/g.
(B1): The melt flow rate is 3.0 to 50 g/10 minutes measured at a measurement temperature of 190° C. and a load of 2.16 kg according to ASTM D-1238.
(B2): The density is 940 kg/m ³ or more.

[2]
A molded article containing the propylene-based resin composition of the above [1].
[3]
The molded article according to the above [2], which is an injection molded article or an injection blow molded article of the propylene-based resin composition of the above [1].

[4]
The molded article according to the above [2] or [3], which is a container.
[5]
The molded article according to [4], wherein the container is a food packaging container.

[6]
The compact according to [4] or [5], wherein the thinnest portion of the container has a thickness of 0.3 to 2.0 mm.

[7]
A method for producing a molded article, comprising a step of injection molding or injection stretch blow molding the propylene-based resin composition of the above [1].

According to the propylene-based resin composition of the present invention, it is possible to obtain a molded article having excellent high-speed moldability and excellent rigidity and low-temperature impact resistance in a well-balanced manner even when producing a thin-walled molded article.
In addition, the molded article of the present invention has well-balanced rigidity and low-temperature impact resistance.

[Propylene resin composition]
The propylene-based resin composition of the present invention contains 75-92 parts by mass of a propylene-based polymer (A) that satisfies the requirements (A1) to (A5) described later, and an ethylene-based polymer that satisfies the requirements (B1) to (B2) described later. 8 to 25 parts by mass of the polymer (B) (where the total of the propylene-based polymer (A) and the ethylene-based polymer (B) is 100 parts by mass), and 0.02 of the nucleating agent (C) It is characterized by containing up to 1.0 parts by mass.

[Propylene polymer (A)]
The propylene-based resin composition of the present invention contains a propylene-based polymer that satisfies requirements (A1) to (A5) described below. Hereinafter, "the propylene-based polymer (A) that satisfies the requirements (A1) to (A5)" is also simply referred to as "the propylene-based polymer (A)".

The propylene-based polymer (A) is preferably a propylene-based copolymer (a so-called block copolymer ).

(Requirement (A1))
Requirement (A1) is the melt flow rate of the propylene-based polymer (A) measured at a measurement temperature of 230° C. and a load of 2.16 kg in accordance with ASTM D-1238 (hereinafter also referred to as “MFR _A ”). ) is 45 to 195 g/10 minutes. The MFR _A is preferably 60-170 g/10 min, more preferably 80-120 g/10 min.

If the MFR _A is below the above range, short shots may occur when the propylene-based resin composition is injection molded. Also, if the MFR _A exceeds the above range, burrs may occur when the propylene-based resin composition is injection molded.

(Requirement (A2))
Requirement (A2) is that the propylene-based polymer (A) has a portion insoluble in room temperature n-decane (hereinafter also referred to as “D _insol ”) of 80 to 92% by mass, and a portion soluble in room temperature n-decane. It contains 8 to 20% by mass of a portion (hereinafter also referred to as “D _sol ”). However, the sum of the ratio of D _insol and the ratio of D _sol is 100% by mass. Preferably, D _insol is 82-88% by weight and D _sol is 12-18% by weight. Further, room temperature is specifically 25°C.

In the propylene-based polymer (A), the n-decane-insoluble portion (D _insol ) is usually a component mainly composed of structural units derived from propylene, and is considered to have crystallinity and high rigidity. be done. The portion soluble in n-decane (D _sol ) is usually a component mainly composed of structural units derived from propylene and ethylene. The D _sol component does not exhibit crystallinity or has low crystallinity, and is considered to exhibit low glass transition temperature, impact resistance, and compatibility with the ethylene polymer (B). This is sometimes referred to as the rubber component. The propylene-based polymer (A) is usually a propylene-based copolymer (so-called block copolymer) having a n-decane-insoluble portion (D _insol ) and an n-decane-soluble portion (D _sol ). be.

When the proportion of D _sol is below the above range and the proportion of D _insol exceeds the above range, the impact resistance of the molded article obtained from the propylene-based resin composition tends to decrease. This is believed to be due to the fact that the absorption energy against impact decreases as the ratio of D _sol decreases.

On the other hand, when the proportion of D _insol is below the above range and the proportion of D _sol exceeds the above range, the high-speed moldability of the propylene-based resin composition may be poor, and the The rigidity (buckling strength) of the molded body may be inferior.
The ratio of D _insol and the ratio of D _sol are those measured by the method employed in the examples described later.

(Requirement (A3))
Requirement (A3) is that the proportion of ethylene-derived structural units in the D _insol is 0 to 1.0% by mass. This proportion is preferably between 0 and 0.8% by weight. The amount of D _insol is assumed to be 100% by mass. Moreover, the ratio of the structural units being 0% by mass means that the D _insol does not contain any structural units derived from ethylene, or the ratio of the structural units is below the detection limit.

If the proportion of the structural unit exceeds the above range, the high-speed moldability of the propylene-based resin composition may be poor, and the rigidity (buckling strength) of a molded article obtained from the propylene-based resin composition may be poor. Sometimes.
The ratio of the structural units is the one measured by the method employed in the examples described later.

(Requirement (A4))
Requirement (A4) is that the proportion of ethylene-derived structural units in D _sol is 25 to 35% by mass. The amount of D _sol is assumed to be 100% by mass. This proportion is preferably 27 to 35% by weight, more preferably 28 to 34% by weight.

If the ratio of the structural unit is below the above range, the impact resistance of the molded article obtained from the propylene-based resin composition tends to be poor. It is believed that the decrease in the proportion of ethylene in D _sol lowers the glass transition temperature, increases the degree of crystallinity, and reduces the absorption energy against impact.

On the other hand, if the proportion of the structural unit exceeds the above range, the high-speed moldability of the propylene-based resin composition may deteriorate.
The ratio of the structural units is the one measured by the method employed in the examples described later.

(Requirement (A5))
Requirement (A5) is that the intrinsic viscosity of D _sol in decalin at 135° C. (hereinafter also referred to as “intrinsic viscosity [η _sol ]”) is 1.0 to 3.0 dl/g. . The intrinsic viscosity [η _sol ] is preferably 1.4 to 2.8 dl/g.

If the intrinsic viscosity [η _sol ] exceeds or falls below the above range, the impact resistance of the molded article obtained from the propylene-based resin composition may decrease.
The value of the intrinsic viscosity [η _sol ] is the value measured by the method employed in the examples described later.

The propylene-based polymer (A) is generally obtained by copolymerizing propylene and ethylene in the presence of a metallocene compound-containing catalyst or in the presence of a Ziegler-Natta catalyst, although the method for producing the propylene-based polymer (A) is not particularly limited.

The propylene-based polymer (A) is preferably obtained by copolymerizing propylene and ethylene in the presence of a Ziegler-Natta catalyst. This is because a resin having a wide molecular weight distribution and good moldability can be easily obtained.

(Catalyst containing metallocene compound)
As the metallocene compound-containing catalyst, at least one compound selected from a metallocene compound, an organometallic compound, an organoaluminum oxy compound, and a compound capable of forming an ion pair by reacting with the metallocene compound, and, if necessary, A metallocene catalyst comprising a particulate carrier can be mentioned accordingly, and preferably a metallocene catalyst capable of stereoregular polymerization having an isotactic or syndiotactic structure can be mentioned. Among the metallocene compounds, preferred are the crosslinkable metallocene compounds exemplified in WO 01/27124 and the metallocene compounds described in [0068] to [0076] of WO 2010/74001. In addition, compounds that react with organometallic compounds, organoaluminum oxy compounds, and transition metal compounds to form ion pairs, and particulate carriers that are used as necessary are described in International Publication No. 01/27124, The compounds disclosed in Japanese Patent Application Laid-Open No. 11-315109 can be used without limitation.

(Ziegler-Natta catalyst)
The propylene-based polymer (A) can be produced by using a highly stereoregular Ziegler-Natta catalyst. Various known catalysts can be used as the highly stereoregular Ziegler-Natta catalyst. For example, (a) a solid titanium catalyst component containing magnesium, titanium, a halogen and an electron donor, (b) an organometallic compound catalyst component, (c) a cyclopentyl group, a cyclopentenyl group, a cyclopentadienyl group, and A catalyst consisting of an organosilicon compound catalyst component having at least one group selected from the group consisting of these derivatives can be used, and this catalyst component is prepared by a known method, for example, [0078 ] to [0094].

When propylene is polymerized using a catalyst comprising the solid titanium catalyst component (a), the organometallic compound catalyst component (b), and the organosilicon compound catalyst component (c) as described above, prepolymerization is carried out in advance. can also The prepolymerization polymerizes the olefin in the presence of the solid titanium catalyst component (a), the organometallic compound catalyst component (b), and optionally the organosilicon compound catalyst component (c).

As the olefin to be prepolymerized, an α-olefin having 2 to 8 carbon atoms can be used. Specifically, linear olefins such as ethylene, propylene, 1-butene, 1-octene; 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4- methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, etc. can be used. These may be copolymerized.

The prepolymerization is desirably carried out so that about 0.1 to 1000 g, preferably about 0.3 to 500 g of polymer is produced per 1 g of the solid titanium catalyst component (a). If the prepolymerization amount is too large, the production efficiency of the (co)polymer in the main polymerization may decrease. In the prepolymerization, the catalyst can be used at a much higher concentration than in the system in the main polymerization.

In the main polymerization, about 0.0001 to 50 millimoles, preferably about 0.001 to 10 millimoles of the solid titanium catalyst component (a) (or prepolymerization catalyst) is converted to titanium atoms per liter of polymerization volume. It is desirable to use it in quantity. The organometallic compound catalyst component (b) can be used in an amount of about 1 to 2000 mol, preferably about 2 to 500 mol, in terms of the amount of metal atoms, per 1 mol of titanium atoms in the polymerization system. desirable. The organosilicon compound catalyst component (c) is desirably used in an amount of about 0.001 to 50 mol, preferably about 0.01 to 20 mol, per 1 mol of the metal atom in the organometallic compound catalyst component (b).

(Manufacturing method of propylene-based polymer (A))
The propylene-based polymer (A) is obtained by copolymerizing propylene and ethylene in the presence of the aforementioned metallocene compound-containing catalyst or in the presence of a Ziegler-Natta catalyst.

When the propylene-based polymer (A) is produced by continuous multi-stage polymerization, propylene is homopolymerized or propylene and ethylene are copolymerized in each stage.
The polymerization may be carried out by any of a gas phase polymerization method, a liquid phase polymerization method such as a solution polymerization method and a suspension polymerization method, and each stage may be carried out by a separate method. Further, the polymerization may be conducted by either a continuous system or a semi-continuous system, and each stage may be divided into a plurality of polymerization vessels, for example, 2 to 10 polymerization vessels. Industrially, it is most preferable to carry out polymerization by a continuous method. In this case, it is preferable to carry out the second and subsequent polymerizations in two or more polymerization vessels, thereby suppressing the generation of gel. .

As the polymerization medium, inert hydrocarbons may be used, and liquid propylene may be used as the polymerization medium. The polymerization conditions for each stage are such that the polymerization temperature is in the range of about −50 to +200° C., preferably about 20 to 100° C., and the polymerization pressure is normal pressure to 10 MPa (gauge pressure), preferably about 0.2 to 5 MPa. (gauge pressure).

The propylene-based polymer (A) can be prepared, for example, by continuously performing the following two steps ([step 1] and [step 2]) in a reactor in which two or more polymerization vessels are connected in series. can get. In the production of the propylene-based polymer (A), a polymerization apparatus in which two or more reactors are connected in series may be used and [Step 1] may be performed in each polymerization apparatus. [Step 2] may be performed in each of the polymerization apparatuses connected in series. Further, [Step 1] and [Step 2] are performed separately, and the polymers obtained in each are melt-kneaded using a single-screw extruder, a multi-screw extruder, a kneader, a Banbury mixer, etc., and propylene-based polymer Coalescence (A) may be produced.

A method for producing the propylene-based polymer (A) by continuously performing [Step 1] and [Step 2] will be described below.
[Step 1] is a step of polymerizing propylene and optionally ethylene at a polymerization temperature of 0 to 100° C. and a polymerization pressure of normal pressure to 5 MPa gauge pressure. In this process, a small amount of ethylene is supplied to the D _insol to produce a propylene-based polymer, which is the main component of D insol. If necessary, a chain transfer agent typified by hydrogen gas may be introduced to adjust the intrinsic viscosity [η] of the polymer produced in [Step 1].

[Step 2] is a step of copolymerizing propylene and ethylene at a polymerization temperature of 0 to 100° C. and a polymerization pressure of normal pressure to 5 MPa gauge pressure. 1] to produce propylene-ethylene copolymer rubber, which is the main component of D _sol . If necessary, a chain transfer agent typified by hydrogen gas may be introduced to adjust the intrinsic viscosity [η] of the polymer produced in [Step 2].

The propylene-based polymer (A) is obtained by continuously performing the above [Step 1] and [Step 2], and the requirements (A1) to (A5) can be adjusted as follows.
MFR _A in requirement (A1) is the feed amount of monomers (that is, propylene in the case of homopolymerization of propylene, propylene and ethylene in the case of copolymerization) when performing [Step 1] or [Step 2] It can be adjusted by adjusting the feed rate of hydrogen gas as a chain transfer agent. That is, by increasing this ratio, MFR _A can be increased, and by decreasing this ratio, MFR _A can be decreased.

In addition to the above method, the MFR _A can also be adjusted by subjecting the propylene-based polymer obtained by polymerization to a melt-kneading treatment in the presence of an organic peroxide. By subjecting the propylene-based polymer obtained by polymerization to a melt-kneading treatment in the presence of an organic peroxide, the MFR _A becomes higher, and the organic peroxide is reduced when the melt-kneading treatment is performed in the presence of an organic peroxide. The MFR _A becomes higher by increasing the amount of additive added. When the propylene-based polymer obtained by polymerization is melt-kneaded in the presence of an organic peroxide, the organic peroxide is used in an amount of 0.005 to 0.05 parts by mass with respect to 100 parts by mass of the propylene-based polymer. is desirable. Moreover, the melt-kneading treatment in the presence of the organic peroxide may be performed after the following post-treatment step. The organic peroxide is not particularly limited, and conventionally known organic peroxides such as 2,5-di-methyl-2,5-di-(benzoylperoxy)hexane and 1,3-bis-( t-butylperoxyisopropyl)benzene).

The ratio of D _insol and the ratio of D _sol in requirement (A2) can be adjusted by adjusting the polymerization time in [Step 1] and [Step 2]. That is, by increasing the proportion of the polymerization time in [Step 1] in the total polymerization time, the proportion of D _insol can be increased and the proportion of D _sol can be decreased. Further, by increasing the ratio of the polymerization time of [Step 2] to the total polymerization time, the ratio of D _insol can be decreased and the ratio of D _sol can be increased.

The ratio of ethylene-derived structural units in the D _insol in requirement (A3) can be adjusted by adjusting the ratio of the ethylene feed amount to the propylene feed amount during [Step 1]. That is, by increasing the feed rate, the proportion of the structural unit can be increased, and by decreasing the feed rate, the proportion of the structural unit can be decreased.

The ratio of ethylene-derived structural units in D _sol in requirement (A4) can be adjusted by adjusting the ratio of the ethylene feed amount to the propylene feed amount when performing [Step 2]. That is, by increasing the feed rate, the proportion of the structural unit can be increased, and by decreasing the feed rate, the proportion of the structural unit can be decreased.

The limiting viscosity [η _sol ] in the requirement (A5) can be adjusted by adjusting the feed amount of hydrogen gas used as a chain transfer agent when performing [Step 2]. In other words, the limiting viscosity [η _sol ] can be decreased by increasing the ratio of the hydrogen gas feed rate to the monomer (i.e., propylene and ethylene) feed rate, and the ratio of the hydrogen gas feed rate to the monomer feed rate is By decreasing the ratio, the intrinsic viscosity [η _sol ] can be increased.

After completion of the polymerization, the propylene-based polymer (A) is obtained as a powder by carrying out known post-treatment steps such as a catalyst deactivation treatment step, a catalyst residue removal step, a drying step, and the like, if necessary.
Moreover, you may use a commercial item as a propylene-type polymer (A).

[Ethylene polymer (B)]
The propylene-based resin composition of the present invention contains an ethylene-based polymer (B) that satisfies requirements (B1) to (B2) described below. Hereinafter, "the ethylene-based polymer (B) that satisfies the requirements (B1) to (B2)" is also simply referred to as "the ethylene-based polymer (B)".

Examples of the ethylene-based polymer (B) include ethylene homopolymers and ethylene/α-olefin copolymers.
Examples of the α-olefins include α-olefins having 3 to 20 carbon atoms, examples of which include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1 -pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like.

(Requirement (B1))
Requirement (B1) is the melt flow rate of the ethylene polymer (B) measured at a measurement temperature of 190 ° C. and a load of 2.16 kg in accordance with ASTM D-1238 (hereinafter also simply referred to as "MFR _B " ) is 3.0 to 50 g/10 minutes. The MFR _B is preferably 3.0 to 30 g/10 minutes, more preferably 3.0 to 20 g/10 minutes.

If the MFR _B is below the above range, the impact resistance of the molded article obtained from the propylene-based resin composition may be poor. If the MFR _B exceeds the above range, the shape of dispersion in the propylene-based resin composition becomes too small, so that the energy absorbed against impact decreases, and the impact resistance of the molded product obtained from the propylene-based resin composition is reduced. may be inferior.

(Requirement (B2))
Requirement (B2) is that the density of the ethylene polymer (B) is 940 kg/m ³ or more. The density is preferably 942 kg/m ³ or more, more preferably 945 kg/m ³ or more, still more preferably 955-980 kg/m ³ .

If the density of the ethylene-based polymer (B) is below the above range, the high-speed moldability of the propylene-based resin composition may be poor, and the rigidity (buckling) of the molded product obtained from the propylene-based resin composition may strength) may be inferior.

The value of the density of the ethylene polymer (B) is obtained by heat-treating the strand obtained when measuring the MFR of the ethylene polymer (B) at 120°C for 1 hour and slowly cooling it to room temperature over 1 hour. It was measured by the density gradient tube method using it as a sample.

The ethylene-based polymer (B) can be produced by a conventionally known method.
MFR _B in requirement (B1) is a monomer (that is, in the case of homopolymerization of ethylene It can be adjusted by adjusting the ratio of the feed amount of hydrogen gas as a chain transfer agent to the feed amount of ethylene (or ethylene and α-olefin in the case of copolymerization). That is, the MFR _B can be increased by increasing this ratio, and the MFR _B can be decreased by decreasing this ratio.

The density in the requirement (B2) adjusts the ratio of the α-olefin feed amount to the ethylene feed amount when polymerizing ethylene (or copolymerizing ethylene and α-olefin) to produce the ethylene-based polymer (B). can be adjusted by That is, the density can be lowered by increasing this ratio, and the density can be increased by decreasing this ratio.

Moreover, you may use a commercial item as an ethylene polymer (B). Examples of commercially available products include Neo-Zex (registered trademark) 45200 (MFR = 20 g/10 minutes, density = 943 kg/m ³ ), Neo-Zex 2805JV (MFR = 3.0 g/10 minutes, density = 965 kg/m ³ ), and Hi-Zex. (registered trademark) 2200J (MFR = 5.2 g/10 min, density = 964 kg/m ³ ), HI-ZEX 1700J (MFR = 16 g/10 min, density = 967 kg/m ³ ), (manufactured by Prime Polymer Co., Ltd.) ) and the like.

[Nucleating agent (C)]
The propylene-based resin composition of the present invention contains a nucleating agent (C).
The nucleating agent contained in the propylene-based resin composition of the present invention is not particularly limited. compounds and the like. Preferred nucleating agents are sorbitol nucleating agents, phosphorus nucleating agents, and polymer nucleating agents.

Specific examples of sorbitol-based nucleating agents include 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol (commercially available products containing the compound Product name "Mirad NX8000" series, manufactured by Milliken ("NX8000" is the above chemical substance + fluorescent brightener + blooming agent, "NX8000K" is "NX8000" without fluorescent brightener, "NX8000J" is fluorescent brightener 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di-(p-methylbenzylidene) sorbitol, 1,3-p-chlorobenzylidene -2,4-p-methylbenzylidene sorbitol.

Specific examples of phosphorus-based nucleating agents include sodium-bis-(4-t-butylphenyl) phosphate, potassium-bis-(4-t-butylphenyl) phosphate, sodium-2,2'-ethylidene- Bis(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate, bis(2,4,8,10 -tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxide) sodium salt (trade name “ADEKASTAB® NA-11”) , manufactured by ADEKA Corporation), bis(2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphosine-6- oxide) a composite mainly composed of aluminum hydroxide salt (trade name “ADEKA STAB NA-21” manufactured by ADEKA Corporation), lithium-2,2′-methylene-bis(4,6-di-t-butyl A complex containing phenyl)phosphate and 12-hydroxystearic acid and containing lithium as an essential component (trade name “ADEKA STAB NA-71”, manufactured by ADEKA Corporation) can be mentioned.

Specific examples of carboxylic acid metal salt nucleating agents include pt-butylbenzoic acid aluminum salt, hydroxy-di(pt-butylbenzoic acid) aluminum (trade name “AL-PTBBA”, manufactured by Japan Chemtech). , aluminum adipate, and sodium benzoate.

A branched α-olefin polymer is preferably used as the polymer nucleating agent. Examples of branched α-olefin polymers include 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene , 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene homopolymers, or copolymers thereof, and can include copolymers of them with other α-olefins. Polymers of 3-methyl-1-butene are particularly preferred from the viewpoints of good low-temperature impact resistance and rigidity properties, and economic efficiency.

Specific examples of inorganic compounds include talc, mica, and calcium carbonate.
Among these nucleating agents, bis(2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphosine-6- oxide) sodium salt, 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propiphenyl)methylene]-nonitol, and hydroxy-di(pt-butylbenzoic acid) Aluminum is preferred.

These nucleating agents may be used singly or in combination of two or more.
Since the propylene-based resin composition of the present invention contains the nucleating agent (C), molded articles such as containers formed from the composition of the present invention are excellent in rigidity. It is presumed that this is due to the high rigidity due to the improvement of the degree of crystallinity.
On the other hand, if the content of the nucleating agent is less than the following range, the effect of improving rigidity is insufficient, and if the content of the nucleating agent is greater than the following range, the further improvement effect is small and uneconomical.

[Propylene resin composition]
The propylene-based resin composition of the present invention contains 75 to 92 parts by mass of the propylene-based polymer (A) and 8 to 25 parts by mass of the ethylene-based polymer (B) (provided that the propylene-based polymer (A) and the ethylene-based The total of polymer (B) is 100 parts by mass), and 0.02 to 1.0 parts by mass of nucleating agent (C), preferably 86 to 90 parts by mass of propylene polymer (A), ethylene 10 to 14 parts by mass of the system polymer (B) and 0.04 to 0.40 parts by mass of the nucleating agent (C).

In addition to these three components, the propylene-based resin composition of the present invention may also contain a neutralizing agent, an antioxidant, a heat stabilizer, a weathering agent, a lubricant, an ultraviolet absorber, Additives such as antistatic agents, antiblocking agents, antifogging agents, antifogging agents, dispersing agents, flame retardants, antibacterial agents, fluorescent brightening agents, cross-linking agents, and cross-linking aids; examples include coloring agents such as dyes and pigments components (hereinafter referred to as "other components").

When the propylene-based resin composition of the present invention contains other components, the amount of the other components is It is usually 0.01 to 5 parts by mass.

The melt flow rate of the propylene-based resin composition of the present invention measured at a measurement temperature of 230° C. and a load of 2.16 kg according to ASTM D-1238 (hereinafter also simply referred to as “MFR”) is propylene It is preferably from 50 to 140 g/10 minutes, more preferably from 60 to 120 g/10 minutes, because of excellent fluidity during injection molding of the resin composition.

The MFR of the propylene-based resin composition of the present invention can be determined by appropriately selecting the melt flow rate of the propylene-based polymer (A) or the melt flow rate of the ethylene-based polymer (B), or the propylene-based polymer (A ) and the ethylene-based polymer (B).

The MFR of the propylene-based resin composition of the present invention can also be adjusted by allowing each component to coexist with an organic peroxide when melt-kneading each component with a kneader. That is, the MFR of the propylene-based resin composition can be increased by adding an organic peroxide during melt-kneading or by increasing the amount of the organic peroxide added during melt-kneading. .

The organic peroxide is not particularly limited, but conventionally known organic peroxides such as 2,5-dimethyl-2,5-di-(benzoylperoxy)hexane, 1,3-bis- (t-butylperoxyisopropyl)benzene may be mentioned. When using an organic peroxide, the organic peroxide is 0.005 to 0.05 with respect to a total of 100 parts by mass of the propylene polymer (A) and the ethylene/α-olefin copolymer (B). It is desirable to use parts by mass.

The propylene-based resin composition of the present invention has a so-called sea-island structure in which D _insol is a continuous phase, that is, a sea portion, and D _sol and the ethylene polymer (B) are mainly island portions. Therefore, the propylene-based resin composition of the present invention can achieve both high rigidity and high low-temperature impact resistance.

The production method of the propylene-based resin composition of the present invention is not particularly limited, but examples of the production method include a method of melt-kneading each component in a kneader to produce a propylene-based resin composition. Examples of the kneader include a single-screw kneading extruder, a multi-screw kneading extruder, a kneader, a Banbury mixer, a Henschel mixer, and the like. Melt-kneading conditions are not particularly limited as long as the melted resin is not deteriorated by shearing during kneading, heating temperature, heat generation due to shearing, or the like. From the viewpoint of preventing deterioration of the molten resin, it is effective to appropriately set the heating temperature and add antioxidants and heat stabilizers.

[Molded body]
The molded article of the present invention is characterized by containing the propylene-based resin composition of the present invention described above. Specific examples thereof include injection molding or injection blow molding of the propylene-based resin composition of the present invention.

Examples of the molded article of the present invention include containers, household appliance parts, daily necessities, and the like. Among them, a container is preferable from the viewpoint of impact resistance and rigidity.
Examples of the container include packaging containers for liquid daily necessities such as hair wash, hair conditioner, cosmetics, detergents, and disinfectants; food packaging containers for liquids such as soft drinks, water, and seasonings; food packaging containers for solids (dessert cups); packaging containers for other chemicals; packaging containers for industrial liquids;

Since the molded article of the present invention is excellent in well-balanced rigidity and low-temperature impact resistance, it can be preferably used as a food packaging container (dessert cup) among these containers.
As for the dessert cup, it is preferable that the thickness of the container body portion (the thinnest portion) is in the range of 0.3 to 2.0 mm. The molded article of the present invention is excellent in low-temperature impact resistance even though it is thin as described above, and is also excellent in moldability.

Further, the method for producing a molded article of the present invention is characterized by including the step of molding the propylene-based resin composition of the present invention described above. Molding methods preferably include injection molding and injection stretch blow molding.

As an injection molding method, for example, molding can be performed using an injection molding machine in the following manner. First, the propylene-based resin composition is introduced into the hopper of the injection mechanism, fed into a cylinder heated to about 200° C. to 250° C., kneaded and plasticized to be melted. This is poured from the nozzle at high pressure and high speed (maximum pressure 50-200 MPa) into a mold closed by a mold clamping mechanism, which is temperature-controlled to 5-50°C, preferably 10-40°C, with cooling water or warm water. inject. It can be carried out by cooling and solidifying the injected propylene-based resin composition by cooling from the mold, opening the mold with a mold clamping mechanism, and obtaining a molded product.

In injection stretch blow molding, for example, a propylene-based resin composition is introduced into the hopper of an injection molding machine, and the resin is fed into a cylinder heated to about 200° C. to 250° C., kneaded and plasticized to a molten state. do. This is poured from the nozzle at high pressure and high speed (maximum pressure 50-200 MPa) into a mold closed by a mold clamping mechanism, which is temperature-controlled to 5-80°C, preferably 10-60°C, with cooling water or warm water. Injection molding, cooling there for 1.0 to 3.0 seconds to form a preform, then immediately opening the mold and using stretch rods to stretch orient in the machine direction, and then stretch orient in the transverse direction by blow molding. It can be done by obtaining a molded product by letting it.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these.
[Raw materials and methods for measuring their physical properties]
The physical properties of raw materials were measured by the following methods.

<Properties of propylene-based polymer>
MFR
The melt flow rate (MFR) of the propylene-based polymer was measured according to ASTM D-1238 (measurement temperature 230°C, load 2.16 kg).

In addition, the precipitate (α) obtained when the following ratio of D _insol was determined was used as a measurement sample, and the melt flow rate of D _insol was determined according to ASTM D-1238 (measurement temperature 230 ° C., load 2.16 kg). (MFR) was measured.

Proportion of D _insol and Proportion of D _sol To 5 g of a propylene polymer sample, 200 ml of n-decane was added and dissolved by heating at 145° C. for 30 minutes to obtain solution (1).

Next, solution (1) was cooled to room temperature (25° C.) over about 2 hours and allowed to stand at 25° C. for 30 minutes to obtain solution (2) containing precipitate (α). After that, the precipitate (α) was separated from the solution (2) by filtration with a filter cloth having an opening of about 15 μm, dried, and then the mass of the precipitate (α) was measured. The ratio of the n-decane insoluble portion (D _insol ) was obtained by dividing the mass of the precipitate (α) by the mass of the sample (5 g).

Further, the solution (2) obtained by filtering the precipitate (α) is placed in about three times the amount of acetone of the solution (2) to precipitate the components dissolved in n-decane, and the precipitate (β ). After that, the precipitate (β) was separated by filtration through a glass filter (G2, opening about 100 to 160 μm) and dried, and then the mass of the precipitate (β) was measured. The ratio of the n-decane soluble portion (D _sol ) was obtained by dividing the mass of the precipitate (β) by the mass of the sample (5 g).

Proportion of ethylene-derived structural units in D _insol and ratio of ethylene-derived structural units in D _sol Using the precipitate (α) obtained when measuring the proportion of D _insol as a sample, the following conditions were applied. ¹³ C-NMR measurement was carried out.
( ¹³ C-NMR measurement conditions)
Measurement device: JEOL LA400 type nuclear magnetic resonance device Measurement mode: BCM (Bilevel Complete decoupling)
Observation frequency: 100.4MHz
Observation range: 17006.8Hz
Pulse width: C nucleus 45° (7.8 μs)
Pulse repetition time: 5 seconds Sample tube: 5 mmφ
Sample tube rotation speed: 12 Hz
Accumulation times: 20000 times Measurement temperature: 125°C
Solvent: 1,2,4-trichlorobenzene: 0.35 ml/heavy benzene: 0.2 ml
Sample amount: about 40 mg

From the spectrum obtained by the measurement, the ratio of the monomer chain distribution (triad (triad) distribution) was determined according to the following document (1), and the molar fraction of the ethylene-derived structural units in the D _insol ( mol%) (hereinafter referred to as E (mol%)) and the molar fraction (mol%) of propylene-derived structural units (hereinafter referred to as P (mol%)) were calculated. From the obtained E (mol%) and P (mol%), the ratio (mass%) of the ethylene-derived structural unit in the D _insol (hereinafter referred to as E (mass%)) is calculated according to the following (formula 1). did.

Reference (1): Kakugo, M.; Naito, Y.; Mizunuma, K.; Miyatake, T., Carbon-13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared with delta-titanium trichloride-diethylaluminum chloride. Macromolecules 1982 , 15, (4), 1150-1152
E (mass%) = E (mol%) x 28 x 100/[P (mol%) x 42 + E (mol%) x 28] (Formula 1)

Furthermore, except that the sample was changed to the precipitate (β) obtained when the proportion of D _sol was measured, by the same method as the above-mentioned method for measuring the proportion of ethylene-derived structural units in D _insol , The proportion of ethylene-derived structural units in D _sol was calculated.

Intrinsic viscosity of D _sol [η _sol ]
As a sample, the precipitate (β) obtained when the ratio of D _sol was determined was used.
About 25 mg of this sample was dissolved in 25 ml of decalin, and the specific viscosity ηsp was measured in an oil bath at 135°C.

5 ml of the decalin solvent was added to the decalin solution to dilute it, and then the specific viscosity ηsp was measured in the same manner.
This dilution operation is repeated twice, and the value of _ηsp /C when the concentration (C) is extrapolated to 0 is obtained as the intrinsic viscosity. _sol ].

<Physical properties of ethylene polymer>
MFR
Melt flow rate (MFR) was measured according to ASTM D-1238 (measurement temperature 190°C, load 2.16 kg).

The strand obtained when measuring the density melt flow rate (ASTM D-1238) was heat-treated at 120 ° C. for 1 hour and slowly cooled to room temperature over 1 hour, and the density was measured by the density gradient tube method. was performed to determine the density of the ethylene-based polymer.

[Raw materials of composition]
[Propylene polymer]
As the propylene-based polymer, the following propylene-based polymers (A-1) to (A-17) were produced.

[Production Example 1] (Production of propylene-based polymer (A-1))
(1) Preparation of Solid Catalyst Component 95.2 g of anhydrous magnesium chloride, 442 ml of decane and 390.6 g of 2-ethylhexyl alcohol are heated at 130° C. for 2 hours to form a homogeneous solution, and 21 of phthalic anhydride is added to this solution. 3 g was added, and the mixture was further stirred and mixed at 130° C. for 1 hour to dissolve the phthalic anhydride.

After the homogeneous solution thus obtained was cooled to room temperature, 75 ml of this homogeneous solution was dropped into 200 ml of titanium tetrachloride maintained at -20° C. over 1 hour. After the completion of charging, the temperature of the mixed solution was raised to 110°C over 4 hours, and when the temperature reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added, followed by stirring at the same temperature for 2 hours. held.

After completion of the reaction for 2 hours, the solid portion was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110° C. for 2 hours. After completion of the reaction, the solid portion was collected again by hot filtration and thoroughly washed with 110° C. decane and hexane until no free titanium compound was detected in the solution.

Here, the detection of the free titanium compound was confirmed by the following method. 10 ml of the supernatant liquid of the solid catalyst component was collected with a syringe and charged into a 100 ml branched Schlenk tube previously purged with nitrogen. Next, the solvent hexane was dried with a stream of nitrogen, followed by vacuum drying for 30 minutes. 40 ml of ion-exchanged water and 10 ml of 50% by volume sulfuric acid were added thereto and stirred for 30 minutes. This aqueous solution was transferred to a 100 ml volumetric flask through filter paper, followed by conc. 1 ml of H ₃ PO ₄ and 5 ml of 3% H ₂ O ₂ aqueous solution as a coloring reagent for titanium were added, and the volume was made up to 100 ml with deionized water. This volumetric flask was shaken, and after 20 minutes, free titanium was detected by observing absorbance at 420 nm using UV. Free titanium was washed away and free titanium was detected until this absorption was no longer observed.

The solid titanium catalyst component (a) prepared as described above was stored as a decane slurry, part of which was dried for the purpose of investigating the catalyst composition. The composition of the solid titanium catalyst component (a) thus obtained was 2.3% by weight of titanium, 61% by weight of chlorine, 19% by weight of magnesium and 12.5% by weight of DIBP.

(2) Preparation of Prepolymerization Catalyst Components After purging a 500 ml three-necked flask equipped with a stirrer with nitrogen gas, 400 ml of dehydrated heptane, 19.2 mmol of triethylaluminum, 3.8 mmol of dicyclopentyldimethoxysilane, and the above were added. 4 g of solid titanium catalyst component (a) was added. The internal temperature was maintained at 20° C., and propylene was introduced while stirring. After 1 hour, stirring was stopped to obtain a prepolymerized catalyst component (b) in which 2 g of propylene was polymerized per 1 g of the solid titanium catalyst component (a).

(3-1) Polymerization-1 (Polymerization [Step 1])
A 10-L stainless steel autoclave equipped with a stirrer was thoroughly dried and purged with nitrogen, and then 6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmol of dicyclopentyldimethoxysilane were added. After replacing nitrogen in the system with propylene, hydrogen was introduced so that the pressure in the system became 0.80 MPa-G, and then propylene was introduced while stirring.

After the inside of the system stabilized at an internal temperature of 80° C. and a total pressure of 0.8 MPa-G, 20.8 ml of a heptane slurry containing 0.10 mmol of the prepolymerization catalyst component (b) in terms of Ti atoms was added into the system. , while continuously supplying propylene, polymerization was carried out at 80°C for 3 hours.

(3-2) Polymerization-2 (Polymerization [Step 2])
After the completion of the polymerization of the propylene homopolymer (after the above [Step 1]), the internal temperature was lowered to 30°C and the pressure was released. After that, hydrogen was charged so that the pressure in the system was 0.60 MPa-G, followed by a mixed gas having a composition of propylene/ethylene = (4.0 L/min)/(2.4 L/min). introduced. The internal temperature was adjusted to 60° C. and propylene/ethylene copolymerization was carried out for 60 minutes.

After a predetermined time, 50 ml of methanol was added to stop the reaction, and the temperature was lowered and the pressure was removed. The content was transferred to a filtration tank with a total filter and heated to 60° C. for solid-liquid separation. Furthermore, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried. The obtained propylene-based polymer (A-1) had an MFR of 120 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 2] (Production of propylene-based polymer (A-2))
In "Polymerization-1", hydrogen was charged so that the pressure in the system was 0.25 MPa-G, and in "Polymerization-2", the propylene/ethylene copolymerization was carried out for 40 minutes in the same manner as in Production Example 1. and polymerized. The obtained propylene-based polymer (A-2) had an MFR of 60 g/10 min, D _insol of 92% by mass, D _sol of 8% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 3] (Production of propylene-based polymer (A-3))
Polymerization was carried out in the same manner as in Production Example 1 except that in "Polymerization-1" hydrogen was introduced so that the pressure in the system was 1.30 MPa-G. The obtained propylene-based polymer (A-3) had an MFR of 170 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 4] (Production of propylene-based polymer (A-4))
In "Polymerization-1", hydrogen was charged so that the pressure in the system was 1.30 MPa-G, and in "Polymerization-2" the propylene/ethylene copolymerization was carried out for 80 minutes in the same manner as in Production Example 1. and polymerized. The obtained propylene-based polymer (A-4) had an MFR of 140 g/10 min, D _insol of 80% by mass, D _sol of 20% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 5] (Production of propylene-based polymer (A-5))
Polymerization was carried out in the same manner as in Production Example 1 except that the composition of the mixed gas in "Polymerization-2" was changed to propylene/ethylene=(4.0 L/min)/(1.60 L/min). The obtained propylene-based polymer (A-5) had an MFR of 120 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 25% by mass.

[Production Example 6] (Production of propylene-based polymer (A-6))
Polymerization was carried out in the same manner as in Production Example 1 except that the composition of the mixed gas in "Polymerization-2" was changed to propylene/ethylene=(4.0 L/min)/(2.57 L/min). The obtained propylene-based polymer (A-6) had an MFR of 120 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 35% by mass.

[Production Example 7] (Production of propylene-based polymer (A-7))
Polymerization was carried out in the same manner as in Production Example 1 except that in "Polymerization-2" hydrogen was introduced so that the pressure in the system was 1.0 MPa-G. The obtained propylene-based polymer (A-7) had an MFR of 130 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 1.8 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 8] (Production of propylene-based polymer (A-8))
Polymerization was carried out in the same manner as in Production Example 1 except that in "Polymerization-2" hydrogen was introduced so that the pressure in the system was 0.35 MPa-G. The obtained propylene-based polymer (A-8) had an MFR of 110 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 3.0 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 9] (Production of propylene-based polymer (A-9))
In "Polymerization-1", except that ethylene was also introduced so that the ethylene concentration in the gas phase in the polymerization tank was 0.8 mol% (the total of propylene and ethylene was 100 mol%) when propylene was introduced. Polymerization was carried out in the same manner as above. The obtained propylene-based polymer (A-9) had an MFR of 120 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 1.0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 10] (Production of propylene-based polymer (A-10))
Polymerization was carried out in the same manner as in Production Example 1 except that in "Polymerization-1" hydrogen was introduced so that the pressure in the system was 0.15 MPa-G. The obtained propylene-based polymer (A-10) had an MFR of 40 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 11] (Production of propylene-based polymer (A-11))
Polymerization was carried out in the same manner as in Production Example 1 except that in "Polymerization-1" hydrogen was introduced so that the pressure in the system was 1.80 MPa-G. The obtained propylene-based polymer (A-11) had an MFR of 200 g/10 min, a D _insol of 86% by mass, a D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 12] (Production of propylene-based polymer (A-12))
In "Polymerization-1", hydrogen was charged so that the pressure in the system was 0.25 MPa-G, and in "Polymerization-2", propylene/ethylene copolymerization was carried out for 30 minutes in the same manner as in Production Example 1. and polymerized. The obtained propylene-based polymer (A-12) had an MFR of 65 g/10 min, D _insol of 94% by mass, D _sol of 6% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 13] (Production of propylene-based polymer (A-13))
In "Polymerization-1", hydrogen was charged so that the pressure in the system was 1.30 MPa-G, and in "Polymerization-2", propylene/ethylene copolymerization was carried out for 110 minutes in the same manner as in Production Example 1. and polymerized. The obtained propylene-based polymer (A-13) had an MFR of 100 g/10 min, D _insol of 75% by mass, D _sol of 25% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 14] (Production of propylene-based polymer (A-14))
Polymerization was carried out in the same manner as in Production Example 1 except that the composition of the mixed gas in "Polymerization-2" was changed to propylene/ethylene=(4.0 L/min)/(1.40 L/min). The obtained propylene-based polymer (A-14) had an MFR of 120 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 22% by mass.

[Production Example 15] (Production of propylene-based polymer (A-15))
Polymerization was carried out in the same manner as in Production Example 1 except that the composition of the mixed gas in "Polymerization-2" was changed to propylene/ethylene=(4.0 L/min)/(2.65 L/min). The obtained propylene-based polymer (A-15) had an MFR of 120 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The proportion of structural units derived from was 0% by mass, and the proportion of structural units derived from ethylene in D _sol was 38% by mass.

[Production Example 16] (Production of propylene-based polymer (A-16))
Polymerization was carried out in the same manner as in Production Example 1 except that in "Polymerization-2" hydrogen was introduced so that the pressure in the system was 0.32 MPa-G. The obtained propylene-based polymer (A-16) had an MFR of 100 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 3.2 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 0% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Production Example 17] (Production of propylene-based polymer (A-17))
In "Polymerization-1", except that ethylene was also introduced so that the ethylene concentration in the gas phase in the polymerization tank was 0.9 mol% (the total of propylene and ethylene was 100 mol%) when propylene was introduced. Polymerization was carried out in the same manner as above. The obtained propylene-based polymer (A-17) had an MFR of 120 g/10 min, D _insol of 86% by mass, D _sol of 14% by mass, [η _sol ] of 2.5 dl/g, and ethylene in D _insol . The ratio of structural units derived from was 1.6% by mass, and the ratio of structural units derived from ethylene in D _sol was 31% by mass.

[Ethylene polymer]
The following commercially available products were used as the ethylene polymer.
Ethylene-based polymer (B-1): HI-ZEX 2200J (MFR = 5.2 g/10 minutes, density = 964 kg/m ³ )
Ethylene-based polymer (B-2): HI-ZEX 1700J (MFR = 16 g/10 min, density = 967 kg/m ³ )
Ethylene-based polymer (B-3): Neozex 45200 (MFR = 20 g/10 minutes, density = 943 kg/m ³ )
Ethylene polymer (B-4): Neozex 2805JV (MFR = 3.0 g/10 minutes, density = 965 kg/m ³ )
Ethylene-based polymer (B-5): Hi-Zex 3300F (MFR = 1.1 g/10 minutes, density = 950 kg/m ³ )
Ethylene polymer (B-6): Neozex 25200J (MFR = 16 g/10 minutes, density = 926 kg/m ³ )
(both manufactured by Prime Polymer Co., Ltd.)

[Nucleating agent]
The following commercial products were used as nucleating agents.
- Nucleating agent (C-1): ADEKA STAB NA-11 (manufactured by ADEKA Co., Ltd.)
- Nucleating agent (C-2): Mirad NX8000J (manufactured by Milliken)
- Nucleating agent (C-3): AL-PTBBA (manufactured by Japan Chemtech)

[Example 1]
(1) Production and evaluation of propylene-based resin composition
90 parts by mass of the propylene-based polymer (A-1), 10 parts by mass of the ethylene-based polymer (B-1), and 0.1 parts by mass of the nucleating agent (C-1) were stirred and mixed using a Henschel mixer. did.

The resulting mixture was melt-kneaded under the following conditions using a twin-screw extruder (TEM35BS) manufactured by Toshiba Machine Co., Ltd. to obtain strands.
・Model: TEM35BS (35mm twin screw extruder)
・Screw rotation speed: 300 rpm
・Screen mesh: #200
・Resin temperature: 220°C

The resulting strand was cooled with water and then cut with a pelletizer to obtain pellets (1) of the propylene-based resin composition.
Using this pellet (1), the melt flow rate (MFR) (ASTM D-1238, measurement temperature 230° C., load 2.16 kg) and melting point of the propylene-based resin composition were measured by the methods shown below. Carried out. Table 1 shows the results.

MFR (melt flow rate)
Melt flow rate (MFR) was measured according to ASTM D-1238 (measurement temperature 230°C, load 2.16 kg).

Melting point (Tm)
Measurement was performed using a differential scanning calorimeter (DSC, manufactured by PerkinElmer (Diamond DSC)) according to JIS-K7121. The apex of the endothermic peak in the third step measured here was defined as the crystalline melting point (Tm). When there are multiple endothermic peaks, the apex of the maximum endothermic peak is defined as the crystalline melting point (Tm). (Measurement condition)
Measurement environment: Nitrogen gas atmosphere Sample amount: 5 mg
Sample shape: Press film (molded at 230°C, thickness 200-400 μm)
1st step: The temperature is raised from 30° C. to 240° C. at a rate of 10° C./min and held for 10 minutes.
2nd step: The temperature is lowered to 60°C at a rate of 10°C/min.
3rd step: Heat up to 240°C at 10°C/min.

(2) Manufacture and evaluation of containers
0.5 mmt beverage container molding Using an electric injection molding machine (Fanuc Roboshot S-2000i-100B) with a mold clamping force of 100 tons, cylinder temperature 250 ° C., mold temperature 20 ° C., injection primary pressure 150 MPa, injection Under the conditions of a speed of 100 mm/sec, a holding pressure of 80 MPa, and a holding pressure time of 1.3 seconds, pellets (1) of the propylene-based resin composition were injection molded to a height of 110 mm, a flange diameter of 70 mm, and a side wall thickness of 0.5 mm. of containers (cups) were injection molded.
The obtained container was evaluated as follows. Table 1 shows the results.

High-speed moldability In continuous molding under the above molding conditions, the minimum cycle time was measured to enable molding without problems such as mold release failure, container deformation, and breakage during ejection for 100 shots.

The appearance of the defective product container was observed. The meanings of symbols in Tables 1 and 2 are as follows.
○: No product defects occurred ×: Sink phenomenon such as dents on the container surface due to the occurrence of burrs on the flange surface, which is the end of the flow, and the phenomenon that the end was not filled, and insufficient filling occurred.

The container with the obtained rigidity is conditioned for 48 to 72 hours at 24 ° C., and a universal testing machine (Shimadzu Corporation, AG-1000KNX wide 250 mm) is used to hold the container in a vertical state (with the opening facing downward. A load was applied from the top surface of the container while the container was in a closed state), and the maximum load until the container was deformed was measured.

Impact Resistance The resulting container was conditioned at 24°C for 48-72 hours, and further conditioned at 5°C for 24 hours or more.

Place the container after conditioning on a flat iron plate so that the bottom of the container faces up in a -5 ° C environment, drop an iron plate with a mass of 6.8 kg from a height of 100 cm onto the container, and check the state of the container. Observed.

The symbols in Table 1 have the following meanings.
Good: The container was crushed, but no cracks or breakage occurred.
x: The container was cracked or glass-like broken.

[Examples 2 to 13 and Comparative Examples 1 to 13]
Pellets of a propylene-based resin composition were produced in the same manner as in Example 1, except that the types and amounts of the propylene-based polymer, ethylene-based polymer, and nucleating agent were changed as shown in Tables 1 and 2. , containers were manufactured, and these were further evaluated. Results are shown in Tables 1 and 2.

Claims (7)

75 to 92 parts by mass of a propylene polymer (A) satisfying the following requirements (A1) to (A5);
8 to 25 parts by mass of an ethylene polymer (B) that satisfies the following requirements (B1) to (B2) (provided that the total amount of the propylene polymer (A) and the ethylene polymer (B) is 100 parts by mass) ), and a propylene-based resin composition containing 0.02 to 1.0 parts by mass of a nucleating agent (C).
(A1): According to ASTM D-1238, the melt flow rate measured at a measurement temperature of 230°C and a load of 2.16 kg is 45 to 195 g/10 minutes.
(A2): Contains 80 to 92% by mass of a portion insoluble in room temperature n-decane and 8 to 20% by mass of a portion soluble in room temperature n-decane.
(A3): The proportion of ethylene-derived structural units in the portion insoluble in n-decane at room temperature is 0 to 1.0% by mass.
(A4): The proportion of ethylene-derived structural units in the portion soluble in room temperature n-decane is 25 to 35% by mass.
(A5): The intrinsic viscosity [η] of the portion soluble in room temperature n-decane in decalin at 135° C. is 1.0 to 3.0 dl/g.
(B1): The melt flow rate is 3.0 to 50 g/10 minutes measured at a measurement temperature of 190° C. and a load of 2.16 kg according to ASTM D-1238.
(B2): The density is 940 kg/m ³ or more. A molded article comprising the propylene-based resin composition according to claim 1 . 3. The molded article according to claim 2, which is an injection molded article or an injection blow molded article of the propylene-based resin composition according to claim 1. 4. The molded article according to claim 2 or 3, which is a container. 5. The molded article according to claim 4, wherein said container is a food packaging container. 6. The molded article according to claim 5, wherein the thinnest portion of the container has a thickness of 0.3 to 2.0 mm. A method for producing a molded article, comprising a step of injection molding or injection stretch blow molding the propylene-based resin composition according to claim 1 .