JP2008266502A - Polypropylene-based resin composition and film comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene-based resin composition excellent in blocking resistance, transparency and impact resistance. <P>SOLUTION: The polypropylene-based resin composition comprises 88-99 wt.% propylene-based polymer (A), 1-12 wt.% propylene-based elastomer (B). The propylene-based polymer (A) is a propylene-based polymer which has 125-155°C melting point, 83-98.5 wt.% propylene content, 0.5-7 wt.% ethylene content and 1-10 wt.% 4-20C α-olefin content. The propylene-based elastomer (B) is a propylene-based elastomer which has 60-94 wt.% propylene content, 6-40 wt.% ethylene content and ≤-10°C glass transition temperature, wherein, the elastomer (B) has, in<SP>13</SP>C-NMR spectrum, two peaks corresponding to 2,1-insertion error on 14-16 ppm and the peak strength ratio of the peaks is 0.5-1.5 times. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polypropylene resin composition comprising a blend of a propylene polymer and a propylene elastomer and a film comprising the same. More specifically, the present invention relates to a polypropylene resin composition excellent in transparency, impact resistance and blocking resistance, and a film containing the same.

Polypropylene films made of a blend of polypropylene and propylene elastomer are used in the packaging field because of their excellent heat sealability and impact resistance.
For example, JP 2005-508416 A discloses a polypropylene resin composition containing a random copolymer of propylene and ethylene and a propylene elastomer as a means for improving the heat sealability and impact resistance of a packaging film. A packaging film is described.
JP-T-2006-505585 discloses a packaging film comprising a polypropylene resin composition containing at least 40% by weight of a propylene elastomer in polypropylene as a means for improving the heat sealability of a polypropylene film. Are listed.

  In addition, JP-T-2001-512771 discloses a polypropylene system containing 2 to 95% by weight of polypropylene and 5 to 98% by weight of a propylene-based elastomer as means for improving the tensile strength of the thermoplastic polymer blend composition. A resin composition is described.

JP-T-2005-508416 JP-T-2006-505658 JP-T-2001-512771

In order to improve the impact resistance of the polypropylene film, additive components such as polyethylene, a copolymer of propylene and ethylene, an ethylene copolymer elastomer, and a propylene copolymer elastomer may be added. However, since these additive components have low crystallinity, the anti-blocking property of the film with improved impact resistance may not always be sufficient, and the transparency may deteriorate due to the addition.
Under such circumstances, an object of the present invention is to provide a polypropylene resin composition excellent in blocking resistance, transparency and impact resistance, and a film comprising the same.

In view of the actual situation, the present inventors have found that the present invention can solve the above problems as a result of intensive studies, and have completed the present invention.
That is, the present invention relates to a polypropylene resin composition containing the following propylene polymer (A) 88 to 99% by weight and the following propylene elastomer (B) 1 to 12% by weight (however, the polypropylene resin composition). Is 100% by weight).
The propylene polymer (A) is a polymer whose main component is a structure derived from propylene, has a melting point of 125 ° C. to 155 ° C., a propylene content of 83 to 98.5% by weight, and ethylene. A propylene polymer having a content of 0.5 to 7% by weight and an α-olefin content of 4 to 20 carbon atoms of 1 to 10% by weight (provided that the propylene content and the ethylene content are And the α-olefin content is 100% by weight).
The propylene-based elastomer (B) is a polymer whose main component is a structure derived from propylene, and has a propylene content of 60 to 94% by weight and an ethylene content of 6 to 40% by weight (provided that 2) having a glass transition temperature lower than −10 ° C. and corresponding to a 2,1-insertion error at 14-16 ppm in ¹³ C-NMR spectrum. It is a propylene-based elastomer having two peaks and having a peak intensity ratio (high magnetic field peak intensity / low magnetic field peak intensity) of 0.5 to 1.5 times.

  ADVANTAGE OF THE INVENTION According to this invention, the polypropylene resin composition excellent in blocking resistance, transparency, and impact resistance, and the film containing it can be obtained.

  The propylene-based polymer (A) used in the present invention is a polymer whose main component is a structure derived from propylene, has a melting point of 125 ° C. to 155 ° C., and a propylene content of 83 to 96.5 wt. A propylene-based polymer having an ethylene content of 0.5 to 7 wt% and an α-olefin content of 4 to 20 carbon atoms of 1 to 10 wt% (provided that propylene is contained) The sum of the amount, ethylene content and α-olefin content is 100% by weight).

  The propylene polymer (A) is a polymer having a structure derived from propylene as a main component, and is preferably a propylene-ethylene-α-olefin random copolymer from the viewpoint of transparency.

  The propylene-ethylene-α-olefin random copolymer is a chain of structures derived from propylene, a structure derived from ethylene, and an α- having 4 or more carbon atoms such as 1-butene, 1-pentene, 1-hexene. Structures derived from olefins are randomly bonded. The α-olefin is preferably 1-butene or 1-hexene from the viewpoint of copolymerization characteristics and economy.

  The content of the structure derived from ethylene contained in the propylene-ethylene-α-olefin random copolymer (hereinafter referred to as ethylene content) is usually 0.5 to 7% by weight, and α having 4 or more carbon atoms. -Content of structure derived from olefin (hereinafter referred to as α-olefin content) is usually 1 to 10% by weight (however, the total amount of random copolymer is 100% by weight).

  As a propylene-ethylene-α-olefin random copolymer, from the viewpoint of transparency and impact resistance, the ethylene content is preferably 1 to 6% by weight, more preferably 1.5 to 5% by weight. The α-olefin content is preferably 3 to 9% by weight, more preferably 4 to 8% by weight.

  The melting point of the propylene polymer (A) is 125 ° C. to 155 ° C., preferably 126 ° C. to 150 ° C. When the melting point of the polypropylene resin (A) exceeds 155 ° C., the transparency and impact resistance of the polypropylene resin composition may be inferior, and when the melting point is less than 125 ° C., the blocking resistance may be inferior. .

As a manufacturing method of a propylene polymer (A), the manufacturing method using a generally well-known polymerization catalyst and a well-known polymerization method is mentioned.
As a known polymerization catalyst, for example, a Ti-Mg-based catalyst composed of a solid catalyst component obtained by complexing a Ti compound with a magnesium compound, an organoaluminum compound and a solid catalyst component obtained by complexing a Ti compound with this magnesium compound, and Examples include a catalyst in which a third component such as an electron donating compound is combined as necessary.

  Preferably, for example, magnesium, titanium and halogen described in JP-A-61-218606, JP-A-61-287904, JP-A-7-216017, JP-A-2004-67850 and the like are essential. The catalyst comprises a solid catalyst component, an organoaluminum compound, and an electron donating compound.

  Known polymerization methods include solvent polymerization performed in the presence of an inert solvent, bulk polymerization performed in the presence of a liquid monomer in the absence of a substantially liquid medium, and in the presence of a gaseous monomer. Examples of the polymerization method include a vapor phase polymerization method, a polymerization method including a combination thereof, and the like, and a polymerization method including a gas phase polymerization method, a bulk polymerization method, or a combination of the bulk polymerization method and the gas phase polymerization method is preferable.

  The melt flow rate of the propylene-based polymer (A) used in the present invention is preferably 2 to 20 g / 10 minutes, more preferably 5 to 15 g / 10 minutes, from the viewpoint of processability or transparency.

  The propylene-based elastomer (B) used in the present invention is a polymer whose main component is a structure derived from propylene, the propylene content is 60 to 94% by weight, and the ethylene content is 6 to 40% by weight. (However, the total of the propylene content and the ethylene content is 100% by weight).

The propylene-based elastomer (B) has a glass transition temperature lower than −10 ° C. The propylene-based elastomer (B) has two peaks corresponding to 2,1-insertion error at 14 to 16 ppm in the ¹³ C-NMR spectrum, and the peak intensity ratio of the peaks (high magnetic field peak intensity / low The magnetic field peak intensity) is 0.5 to 1.5 times.
Two peaks at 14-16 ppm are shown in Macromolecules, Vol. 27, 7538-7543 (1994), Angew. Chem. Int. Ed. Engl, Vol. 34, 1143-1170 (1995) and Macromolecules, Vol. 32,8283-8290 (1999) means a 2,1-insertion error of propylene units into the growing polymer chain.

The melt flow rate of the propylene-based elastomer (B) used in the present invention is preferably 0.5 to 10 g / 10 minutes, more preferably 1 to 8 g / 10 minutes, from the viewpoint of impact resistance.

As a method for producing the propylene-based elastomer (B), for example, a homogeneous catalyst (for example, a nonmetallocene catalyst is mentioned, and in detail, a heteroaryl ligand catalyst described in JP-T-2005-508416) is used as a solution Examples thereof include a method of production by polymerization, slurry polymerization, suspension polymerization, high pressure polymerization, gas phase polymerization and the like. Non-metallocene catalyst means a catalyst in which the metal of the catalyst is not bound to a substituted or unsubstituted cyclopentadienyl ring.

The content of the propylene polymer (A) contained in the polypropylene resin composition of the present invention is 88 to 99% by weight, and the content of the propylene elastomer (B) is 1 to 12% by weight (however, The total weight of the polypropylene resin composition is 100% by weight).
From the viewpoint of transparency and blocking resistance, the content of the propylene polymer (A) is preferably 94 to 98.7% by weight, more preferably 96 to 98.5% by weight. The content of B) is preferably 1.3 to 6% by weight, more preferably 1.5 to 4% by weight.

When the content of the propylene-based polymer (A) is less than 88% by weight (that is, when the content of the propylene-based elastomer (B) exceeds 12% by weight), transparency and blocking resistance deteriorate. There is. Further, when the content of the propylene polymer (A) exceeds 99% by weight (that is, when the content of the propylene elastomer (B) is less than 1% by weight), the impact resistance may be inferior. .

As a manufacturing method of the polypropylene resin composition of the present invention, for example,
(1) A method in which the propylene polymer (A) and the propylene elastomer (B) are mixed and melt-kneaded,
(2) A method of mixing and melt-kneading the propylene polymer (A) and the propylene elastomer (B) when forming a film,
Etc.

You may add an additive and another resin to the polypropylene resin composition of this invention as needed.
Examples of additives include neutralizers, organic peroxides, weathering agents, flame retardants, antistatic agents, plasticizers, lubricants, nucleating agents, copper damage inhibitors, antioxidants, antiblocking agents, and chlorine supplements. An agent or the like may be added. These additives may be used alone or in combination of at least two kinds.
Examples of other resins include ethylene-α-olefin copolymers and ethylene homopolymers.

Examples of the neutralizing agent include fatty acid calcium salts and hydrotalcite, and the content thereof is preferably 0.005 to 0.5 parts by weight with respect to 100 parts by weight of the polypropylene resin composition.
As the organic peroxide, those that are industrially easy to handle are preferred, and for example, those having a half-life at 150 ° C. of 0.5 minutes or more are preferred. Specific examples of such organic peroxides include 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 1,1-bis (tert-butylperoxy) 3, 3,5. -Trimethylcyclohexane, tert-butylperoxy-iso-propyl carbonate, tert-butylpa-3,3,5-trimethylhexanoate, 1,3 bis (2-tert-butylperoxyiso-propyl) benzene, etc. be able to.
Antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and phosphite antioxidants.

The polypropylene film of the present invention is a polypropylene film containing the polypropylene resin composition of the present invention, may be a single layer film, and has at least a layer containing the polypropylene film of the present invention. It may be a multilayer film having one.
The thickness of the polypropylene film of the present invention is usually 10 to 500 μm, preferably 10 to 150 μm.

  The method for producing a polypropylene film of the present invention includes, for example, a commonly used inflation method, a casting method using a T-die, etc. as a method for producing a monolayer film, and a method for producing a multilayer film includes, for example, Examples of the processing method and extrusion laminating method include coextrusion of the layer made of the polypropylene film of the present invention and other layers by a commonly used inflation method, a casting method using a T die, and the like. A casting method using a T die is preferable.

  Moreover, an unstretched film may be sufficient and a stretched film may be sufficient. In the case of producing a stretched film, examples of the stretching method include a method of stretching uniaxially or biaxially using a roll stretching method, a tenter stretching method, a tubular stretching method, or the like.

The polypropylene film of the present invention is preferably an unstretched film produced by a casting method using a T die from the viewpoint of transparency and the like.

  Examples of the use of the polypropylene film of the present invention include packaging applications and the like, for example, packaging applications such as foods, fibers and sundries.

Moreover, what bonded together the polypropylene-type film of this invention and another film is also used suitably. Examples of other films include polypropylene films other than the polypropylene film of the present invention, polyethylene films, polyester films, polyamide films, polystyrene films, aluminum foil, paper, and the like.
Examples of the bonding method include a heat laminating method and a dry laminating method.

Hereinafter, the present invention will be described using examples and comparative examples. The measured value of each item in an Example and a comparative example was measured with the following method.
(1) Melt flow rate (MFR, unit: g / 10 minutes)
The melt flow rate was measured according to JIS K7210. The melt flow rates of the propylene polymer (A) and the propylene elastomer (B) were measured at a temperature of 230 ° C. and a load of 21.18 N.

(2) Ethylene content of propylene polymer (unit:% by weight)
It was determined by the method described on page 616 of a polymer handbook (published by Kinokuniya, 1995).

(3) 1-butene content (% by weight) of propylene polymer
It was determined by the method described on page 618 of the Polymer Handbook (published by Kinokuniya, 1995).

(4) Detection of ethylene content (unit:% by weight) of propylene-based elastomer and peak of 2,1-insertion error at 14 to 16 ppm of ¹³ C-NMR spectrum Proton resonance frequency equipped with a probe for a glass sample tube having a diameter of 10 mm ¹³ C-NMR was measured using a 600 MHz nuclear magnetic resonance apparatus (trade name AVANCE 600 (manufactured by Bruker)). The calculation of the ethylene content is described in Macromolecules, Vol. 17, 1950-1955 (1984). Detection of a region error peak at 14-16 ppm of the ¹³ C-NMR spectrum is described in Macromolecules, Vol. 27, 7538-7543 (1994), Angew. Chem. Int. Ed. Engl, Vol. 34, 1143-1170 (1995) and Macromolecules, Vol. 32, 8283-8290 (1999), and the peak intensity ratio of the peak of the 2,1-insertion error was calculated from the peak area ratio.
The measurement conditions are shown below.
Measurement mode: Proton decoupling method Pulse width: 45 °
Pulse repetition time: 4 sec
Integration count: 3000 times Solvent: 1,2-dichlorobenzene / 1,2-dichlorobenzene-d4 mixed solvent (75/25)
Internal standard: Tetramethylsilane Sample concentration: 200 mg / 3.0 ml Solvent measurement temperature 135 ° C

(5) Melting point (Tm, unit: ° C)
About 10 mg of the test piece was melted at 220 ° C. under a nitrogen atmosphere using a differential scanning calorimeter (Perkin Elmer DSC), and then rapidly cooled to 150 ° C. After holding at 150 ° C. for 1 minute, the temperature was lowered to 50 ° C. at a rate of 5 ° C./min.
Thereafter, the temperature was maintained at 50 ° C. for 1 minute, and then the temperature was raised at 5 ° C./minute. In the obtained melting endothermic curve, the decimal point of the peak temperature of the maximum peak was rounded off to obtain Tm (melting point). For those with multiple peaks, the peak on the high temperature side was adopted.
In addition, Tm of indium (In) measured at a temperature decrease rate of 5 ° C./min and a temperature increase rate using this measuring instrument was 156.6 ° C.

(6) Glass transition temperature of propylene elastomer (unit: ° C)
Using a differential scanning calorimeter (DSC220C manufactured by Seiko Denshi Kogyo Co., Ltd .: input compensation DSC), the temperature was raised from normal temperature to 200 ° C. at 30 ° C./min. The temperature was measured according to JIS K7121 from the endothermic curve when the temperature was raised at 10 ° C./min after the temperature was lowered.
The glass transition temperature was determined by measuring the glass transition temperature (Tg) by drawing the measured values on the horizontal axis -150 to 180 ° C and the vertical axis -3.0 to 3.0 mW.

(7) Haze (Unit:%)
It measured according to JIS K7105.

(8) Impact resistance (unit: Kg · cm / mm)
Using a Toyo Seiki film impact tester, the impact strength of the film was measured at −10 ° C. using a hemispherical impact head having a diameter of 15 mm.

(9) Blocking resistance (unit: Kg / 12cm2)
Using a 150 mm × 30 mm film (collected so that the film forming direction and the long side direction coincide), the two films were overlapped so that the surface in contact with the cooling roll was in contact, and 500 g in a range of 40 mm × 30 mm was obtained. The condition was adjusted at 80 ° C. for 3 hours. Thereafter, the sample was left in an atmosphere of 23 ° C. and 50% humidity for 30 minutes or more, peeled at a rate of 200 mm / min using a tensile tester manufactured by Toyo Seiki, and the strength required for peeling the sample was measured.

Example 1
(Producing method of propylene polymer (PP-1))
A butane, triethylaluminum, and cyclohexylethyldimethoxysilane, which were sufficiently dehydrated and degassed with respect to the solid catalyst component containing magnesium, titanium, and halogen produced according to Example 1 of Japanese Patent Application Laid-Open No. 2004-066785. It was added and propylene was continuously fed for preactivation.
By a polymerization method comprising a combination of a bulk polymerization method and a gas phase polymerization method, a preactivated solid catalyst component, triethylaluminum and cyclohexylethyldimethoxysilane are continuously supplied, and a supply ratio of propylene, ethylene and 1-butene And by adjusting the supply amount of hydrogen and polymerizing, the MFR is 6.0 g / 10 min, the ethylene content is 4.0 wt%, the 1-butene content is 3.6 wt%, and the melting point is A propylene-ethylene-1-butene random polymer (PP-1) having a temperature of 129 ° C. was obtained.

(Production of polypropylene resin composition)
98 parts by weight of the propylene-ethylene-1-butene random polymer (PP-1) obtained by the above polymerization has a melt flow rate of 1.9 g / 10 minutes, a propylene content of 87% by weight, and an ethylene content. Is 13 wt%, has a glass transition temperature of −31 ° C., has two peaks corresponding to 2,1-insertion errors at 14 to 16 ppm in a ¹³ C-NMR spectrum, and the peak intensity ratio ( High magnetic field peak intensity / low magnetic field peak intensity) is 0.8 times propylene elastomer (PER-1: manufactured by Dow Chemical Co., Ltd., trade name: Versify DE2300) with respect to 100 parts by weight of polypropylene resin composed of 2 parts by weight. , Chlorine scavenger hydrotalcite 0.01 parts by weight, antioxidant 2,4,8,10-tetra-t-butyl-6- [3- (3 -Methyl-4-hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,3,2] dioxaphosphine (trade name: Sumilizer GP) 0.1 part by weight was added, and super The mixture was uniformly mixed with a mixer (manufactured by Kawada Manufacturing Co., Ltd.), and kneaded at a resin temperature of 220 ° C. using a 40 mm single screw extruder (manufactured by Tanabe Plastics Machinery Co., Ltd.) to obtain a polypropylene resin composition.

(Film production)
98 parts by weight of the polypropylene-based resin composition obtained by the above kneading is uniformly mixed with 2 parts by weight of an antiblocking agent master batch, and a 50 mm T die film forming apparatus (V-50-F600 type film molding manufactured by Tanabe Plastics Co., Ltd.). The melt extrusion was performed at a resin temperature of 250 ° C. using an apparatus with a 400 mm width T die. The melt-extruded product was cooled with a cooling roll through which cooling water of 30 ° C. was passed to obtain a film having a thickness of 30 μm.
As the antiblocking agent master batch, a 10 wt% master batch of Silicia 550 (manufactured by Fuji Silysia Chemical Co., Ltd.) described in Example 4 of JP-A-2003-170420 was used.

(Example 2)
The same procedure as in Example 1 was carried out except that 4 parts by weight of the propylene-based elastomer (PER-1) and 96 parts by weight of the propylene-ethylene-1-butene random polymer (PP-1) were used.

(Example 3)
(Production method of propylene polymer (PP-2))
The preactivation of the solid catalyst component was performed in the same manner as in Example 1.
By a polymerization method comprising a combination of a bulk polymerization method and a gas phase polymerization method, a preactivated solid catalyst component, triethylaluminum and cyclohexylethyldimethoxysilane are continuously supplied, and a supply ratio of propylene, ethylene and 1-butene And by adjusting the supply amount of hydrogen and polymerizing, the MFR is 7.5 g / 10 min, the ethylene content is 2.0% by weight, the 1-butene content is 5.4% by weight, and the melting point is 136. A propylene-ethylene-1-butene random polymer (PP-2) having a temperature of 0 ° C. was obtained.
(Production of polypropylene resin composition)
Example 1 except that the propylene-ethylene-1-butene random polymer (PP-2) obtained by the above polymerization was used instead of the propylene-ethylene-1-butene random polymer (PP-1). The same was done.
(Film production)
The same operation as in Example 1 was performed.

Example 4
The same procedure as in Example 3 was performed except that the propylene-based elastomer (PER-1) was 4 parts by weight and the propylene-ethylene-1-butene random polymer (PP-2) was 96 parts by weight.

(Comparative Example 1)
The same procedure as in Example 1 was carried out except that 15 parts by weight of the propylene-based elastomer (PER-1) and 85 parts by weight of the propylene-ethylene-1-butene random polymer (PP-1) were used.

(Comparative Example 2)
(Producing method of propylene polymer (PP-3))
The preactivation of the solid catalyst component was performed in the same manner as in Example 1.
A pre-activated solid catalyst component, triethylaluminum, and cyclohexylethyldimethoxysilane are continuously supplied by a polymerization method consisting of a bulk polymerization method and a gas phase polymerization method, and a supply ratio of propylene and ethylene and supply of hydrogen. By adjusting the amount and polymerizing, a propylene-ethylene random polymer (PP-3) having an MFR of 7.5 g / 10 min, an ethylene content of 4.6% by weight, and a melting point of 138 ° C. is obtained. It was.
(Production of polypropylene resin composition)
It carried out similarly to Example 1 except having used the propylene-ethylene random polymer (PP-3) obtained by the said superposition | polymerization instead of the propylene-ethylene-1-butene random polymer (PP-1). .
(Film production)
The same operation as in Example 1 was performed.

(Comparative Example 3)
The same procedure as in Comparative Example 2 was carried out except that the propylene elastomer (PER-1) was 4 parts by weight and the propylene-ethylene random polymer (PP-3) was 96 parts by weight.

(Comparative Example 4)
(Producing method of propylene polymer (PP-4))
The preactivation of the solid catalyst component was performed in the same manner as in Example 1.
A polymerization method consisting of a combination of a bulk polymerization method and a gas phase polymerization method, continuously supplying a preactivated solid catalyst component, triethylaluminum, cyclohexylethyldimethoxysilane and propylene, and adjusting the supply amount of hydrogen for polymerization As a result, the MFR was 8.0 g / 10 min and the melting point was 165 ° C. A propylene polymer (PP-4) was obtained.
(Production of polypropylene resin composition)
It carried out similarly to Example 1 except having used the propylene polymer (PP-4) obtained by the said superposition | polymerization instead of the propylene-ethylene-1-butene random polymer (PP-1).
(Film production)
The same operation as in Example 1 was performed.

Table 1 shows the physical properties of Examples and Comparative Examples.
It can be seen that films containing a polypropylene resin composition satisfying the requirements of the present invention (Example) are excellent in transparency, impact resistance and blocking resistance.
In contrast, the film of Comparative Example 1 that does not satisfy the requirements of the present invention has insufficient transparency and blocking resistance, and the films of Comparative Example 2 and Comparative Example 3 have insufficient blocking resistance. It can be seen that the film of Example 4 has insufficient impact resistance.

Claims (4)

Polypropylene resin composition containing the following propylene polymer (A) 88-99 wt% and the following propylene elastomer (B) 1-12 wt% (however, the total amount of the polypropylene resin composition is 100 wt%) And).
The propylene polymer (A) has a melting point of 125 ° C. to 155 ° C., a propylene content of 83 to 98.5% by weight, an ethylene content of 0.5 to 7% by weight, and a carbon number of 4 A propylene-based polymer having an α-olefin content of 1 to 10% by weight (provided that the total of propylene content, ethylene content and α-olefin content is 100% by weight) .
The propylene elastomer (B) has a propylene content of 60 to 94% by weight and an ethylene content of 6 to 40% by weight (provided that the total of the propylene content and the ethylene content is 100% by weight) ), A glass transition temperature lower than −10 ° C., two peaks corresponding to 2,1-insertion errors at 14 to 16 ppm in a ¹³ C-NMR spectrum, and a peak intensity ratio of the peaks (high magnetic field) It is a propylene-based elastomer having a peak intensity / low magnetic field peak intensity) of 0.5 to 1.5 times.   A polypropylene film comprising the polypropylene resin composition according to claim 1.   The polypropylene film according to claim 2, which is an unstretched film.   The manufacturing method of the polypropylene-type film of Claim 3 manufactured by the casting method.