JP2002080656A - Polypropylenic resin composition, t-die film and manufacturing method of t-die film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylenic resin capable of rectifying defective external appearances of a film even in T-die film processing using a polypropylenic resin having a sharp molecular weight distribution, a T-die film composed of the same, and a manufacturing method of a T-die film permitting rectification in defective external appearances of a film even when a polypropylenic resin having a sharp molecular weight distribution is employed. SOLUTION: The polypropylenic resin composition comprises 100 pts.wt. of a propylene polymer resin (A) having a die swell ratio of less than 1.70 and 0.01-45 pts.wt. of a propylene polymer resin (B) having a die shell ratio of at least 1.80. The T-die film is composed of the polypropylenic resin composition. The manufacturing method of the T-die film comprises using the polypropylenic resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene resin composition suitable for processing a T-die film, a T-die film comprising the same, and a method for producing the T-die film.

[0002]

2. Description of the Related Art Polypropylene films are widely used in packaging fields such as food packaging and textile packaging because of their excellent optical properties, mechanical properties and packaging suitability. When a T-die film is manufactured using a polypropylene resin having a narrow molecular weight distribution for a field such as a film for a retort, the film surface may be roughened in a folded shape and the perceived feeling may be impaired. The problem to be solved by the present invention is to provide a polypropylene resin capable of improving the above-mentioned poor film appearance even when a T-die film processing is performed using a polypropylene resin having a narrow molecular weight distribution, and a T-die comprising the same. It is an object of the present invention to provide a method for producing a T-die film in which the above-described poor film appearance is improved even when a film and a polypropylene resin having a narrow molecular weight distribution are used.

[0003]

According to the present invention, 100 parts by weight of a propylene polymer resin (A) having a die swell ratio of less than 1.70 and 0.01 parts of a propylene polymer resin (B) having a die swell ratio of 1.80 or more are used. The present invention relates to a polypropylene resin composition comprising from 45 to 45 parts by weight, a T-die film comprising the polypropylene resin composition, and a method for producing a T-die film using the polypropylene resin composition. Hereinafter, the present invention will be described in more detail.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polypropylene resin composition of the present invention comprises 100 parts by weight of a propylene polymer resin (A) having a die swell ratio of less than 1.70 and a die swell ratio of 1.8.
A polypropylene-based resin composition comprising 0.01 to 45 parts by weight of 0 or more propylene polymer resin (B). The die swell ratio mentioned here is based on the condition 1 of JIS K7210.
The diameter of the cross section of the extrudate at the time of measuring the melt flow rate (MFR) according to the method of No. 4 is measured, and the value determined from the following equation is adopted. Die swell ratio = diameter of cross section of extrudate / diameter of orifice However, the cross section of extrudate means a cross section perpendicular to the extrusion direction of the extrudate, and when the cross section is not a perfect circle, the maximum diameter of the cross section The average of the value and the minimum value is defined as the diameter of the cross section of the extrudate.

[0005] The propylene polymer resin (A) preferably has a die swell ratio of 1.00 to 1.60. In the present invention, the propylene polymer resin (A) is useful when a resin having a smaller die swell ratio is used, and the propylene polymer resin (A) used in the present invention is used.
The die swell ratio is more preferably 1.05 to 1.
50, and more preferably 1.10 to 1.35. The die swell ratio of the propylene polymer resin (B) is more preferably from 1.80 to 3.00, and even more preferably from 2.00 to 3.00. The amount of the propylene polymer resin (B) is preferably 0.01 to 30 parts by weight, more preferably 0.10 to 20 parts by weight, based on 100 parts by weight of the propylene polymer resin (A). And more preferably 0.20 to 15 parts by weight.

The propylene polymer resin (A) is composed of a propylene homopolymer resin or propylene and α-C 2-12 other than propylene to such an extent that crystallinity is not lost.
-Copolymer resins with olefins and the like, and a plurality of resins selected therefrom are preferred. Examples of the α-olefin include ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like. The copolymerization is performed for the purpose of controlling flexibility and impact resistance, and the content of the repeating unit derived from a monomer other than propylene is 1 in the case of ethylene.
0% by weight or less, preferably 30% by weight or less in the case of an α-olefin having 4 to 12 carbon atoms. Among these, a propylene homopolymer resin, a random copolymer resin of propylene and ethylene having a content of a repeating unit derived from ethylene of 10% by weight or less, and a resin having 4 to 1 carbon atoms
Propylene having a content of the repeating unit derived from the α-olefin of No. 2 of 30% by weight or less and 4 to 4 carbon atoms.
12 random copolymer resin with α-olefin, the content of repeating units derived from ethylene is 10% by weight
A tertiary random copolymer of propylene, ethylene and an α-olefin having 4 to 12 carbon atoms, wherein the content of the repeating unit derived from an α-olefin having 4 to 12 carbon atoms is 30% by weight or less Resins or block copolymer resins of propylene and ethylene are more preferably used. In this case, 1-butene is particularly preferred as the α-olefin.

In the present invention, the propylene polymer resin (A) is useful when a resin having a narrow molecular weight distribution is used, and the propylene polymer resin (A) used in the present invention preferably has a molecular weight distribution of 1 or less. 0.5 to 5.0, and more preferably 1.8 to 4.0.

[0008] The method for producing the propylene polymer resin (A) is not particularly limited, and examples thereof include a gas phase polymerization method and a solvent polymerization method, with the gas phase polymerization method being particularly preferred. As the catalyst used for the polymerization, various known catalysts can be used, and preferably, a multi-site catalyst obtained using a solid catalyst component containing a titanium atom, a magnesium atom and a halogen atom, or a metallocene complex or the like is used. Single-site catalyst.

The propylene polymer resin (B) includes:
Various known propylene polymer resins can be used, and examples thereof include a non-linear propylene polymer resin having a strain-hardening elongational viscosity and a propylene polymer resin having a wide molecular weight distribution produced by multi-stage polymerization. Can be

As the propylene polymer resin (B), the following propylene polymer (C) is preferably used. Propylene polymer (C): a step of producing a crystalline propylene polymer portion (a) having an intrinsic viscosity of 5.0 dl / g or more, and a crystalline propylene polymer portion (b) having an intrinsic viscosity of less than 3.0 dl / g Wherein the proportion of the crystalline propylene polymer portion (a) in the entire resin is 0.05 to 35% by weight, and the intrinsic viscosity of the entire resin is less than 3.0 dl / g. And the molecular weight distribution is 1
Propylene polymer less than 0. As a specific method for producing the propylene polymer (C), for example, after (a) is polymerized in the first stage, (b) is subsequently polymerized in the same polymerization tank as used in the polymerization of (a) in the second stage. In a batch polymerization method for polymerization, two or more polymerization tanks are arranged in series, the product after polymerization of (a) is transferred to the next polymerization tank as the first step, and the second step is performed in the polymerization tank in the second step ( and a continuous polymerization method for polymerizing b). In the case of a continuous polymerization method, the number of polymerization tanks in each of the first and second stages may be one or two or more.

The intrinsic viscosity of the crystalline propylene polymer portion (a) is at least 5.0 dl / g, preferably at least 6.
0 dl / g or more. Within this range, the effect of improving the appearance of the film made of the polypropylene-based resin composition of the present invention is enhanced, which is preferable. The intrinsic viscosity of (a) is preferably as high as possible, and there is no particular upper limit, but usually 15.0 dl.
/ G. The intrinsic viscosity of (a) is more preferably 6.0 to 13.0 dl / g, and still more preferably 7.0 to 11.0 dl / g.

The proportion of the crystalline propylene polymer part (a) in the propylene polymer (C) is 0.05 to 35% by weight, preferably 0.1 to 25% by weight, more preferably 0.3 to 35% by weight. 18% by weight.

The intrinsic viscosity of the crystalline propylene polymer portion (b) is less than 3.0 dl / g, preferably 2.
0 dl / g or less. When it is in this range, the polypropylene resin composition of the present invention is excellent in fluidity and processability, and is preferable. The intrinsic viscosity of (b) is preferably as low as possible, and the lower limit is not particularly limited, but is usually 0.5 dl / g or more. The intrinsic viscosity of (b) is more preferably 0.8 to 2.0.
dl / g, and more preferably 1.0 to 1.8 dl.
/ G.

The intrinsic viscosity of (b) can be set within the above range by appropriately setting the production conditions of (b). Usually, assuming that the additive property of the intrinsic viscosity is satisfied, in the case of the propylene polymer (C) comprising (a) and (b), the intrinsic viscosity [η] of the finally obtained propylene polymer (C) ] intrinsic viscosity _C and the (a) [eta] _a and the (a), (b) the intrinsic viscosity of the content of each of (C) in said by equation 1 below from (wt%) (b) [η ] _B
Ask for. [Η] _b = ([η] _C × 100− [η] _a × W _a ) ÷ W _b [Equation 1] [η] _C : intrinsic viscosity of propylene polymer (C) (dl /
g) [η] _a: Intrinsic viscosity (dl / g) W _a crystalline propylene polymer portion (a): the proportion (wt% of the crystalline propylene polymer portion (a)) W _b: crystalline propylene heavy Content (b%) of coalesced part (b)

The intrinsic viscosity of the entire propylene polymer (C) is less than 3.0 dl / g. When it is in this range, the polypropylene resin composition of the present invention is excellent in fluidity and processability, and is preferable. The intrinsic viscosity of (C) is preferably as low as possible, and the lower limit is not particularly limited, but is usually 1.0 dl / g or more. The intrinsic viscosity of (C) is more preferably 1.0.
It is dl / g or more and less than 3.0 dl / g, and more preferably 1.2 dl / g or more and less than 2.8 dl / g.

The molecular weight distribution of the entire propylene polymer (C) is less than 10. The molecular weight distribution is preferably from 4 to 8. The molecular weight distribution referred to in the present invention is a ratio (Mw) between the weight average molecular weight (Mw) and the number average molecular weight (Mn).
/ Mn).

Furthermore, in order to keep the die swell ratio of the propylene polymer (C) in a suitable range, the intrinsic viscosity [η] _a (dl / g) and the content ratio W _a (% by weight) of ( _a ) are used.
However, it is more preferable that the following formula 2 is satisfied. W _a ≧ 400 × EXP (−0.6 × [η] _a ) [Equation 2]

(A) and (b) are each a crystalline propylene polymer portion having an isotactic polypropylene crystal structure, and a propylene homopolymer;
Alternatively, a copolymer of propylene and a comonomer such as ethylene and / or an α-olefin having 4 to 12 carbon atoms in such an amount that crystallinity is not lost is preferable. Examples of the α-olefin include 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like.
The amount that does not lose crystallinity differs depending on the type of comonomer. For example, in the case of ethylene, the content of the repeating unit derived from ethylene in the copolymer is usually 10% by weight or less, and the content of other units such as 1-butene is 1% or less. In the case of the α-olefin, the content of the repeating unit derived from the α-olefin in the copolymer is usually 30% by weight or less.

In addition to the above (b), the crystalline propylene polymer resin (A) may contain an amorphous ethylene / α
A polymer in which an olefin copolymer is dispersed can also be mentioned as a preferable example. Particularly preferred as (a) and (b) are a homopolymer of propylene, a random copolymer of propylene and ethylene having a content of a repeating unit derived from ethylene of 10% by weight or less, and carbon, respectively. A random copolymer of propylene having a content of a repeating unit derived from an α-olefin having 4 to 12 atoms of 30% by weight or less and an α-olefin having 4 to 12 carbon atoms, or derived from ethylene. Propylene and ethylene having a repeating unit content of 10% by weight or less and a repeating unit derived from an α-olefin having 4 to 12 carbon atoms of 30% by weight or less, and α-olefin having 4 to 12 carbon atoms. It is a ternary random copolymer with an olefin. The most preferred α-olefin in these cases is 1-butene. As (a) showing particularly excellent performance in terms of flexibility and impact resistance, the amount of the repeating unit derived from ethylene is 1 to 1;
A 0% by weight random copolymer of propylene and ethylene is used.

(A) and (b) may have the same composition or different compositions. Further, (a) and (b) may be combined in a block manner. Furthermore, (a) and (b) may be combined in a block-like manner, and the other (a) and (b) may coexist.

The propylene polymer (C) is produced by using various known catalysts. As such a catalyst, a multicomponent catalyst obtained by using a solid catalyst component containing a titanium atom, a magnesium atom and a halogen atom is used. A site catalyst or a single-site catalyst obtained by using a metallocene complex or the like can be used. The propylene polymer (C) is preferably produced using a multi-site catalyst obtained using a solid catalyst component containing a titanium atom, a magnesium atom and a halogen atom, and more preferably disclosed in JP-A-11-228629. It is manufactured by the method described.

The present invention is particularly effective for a polypropylene resin composition having a narrow molecular weight distribution. The molecular weight distribution of the polypropylene resin composition of the present invention is preferably 1.5
-6.0, and more preferably 1.8-4.5.

In order to further improve the physical properties of the polypropylene resin composition of the present invention, 2,6-di-t-butyl-p-cresol (BH) is used as long as the effects of the present invention are not impaired.
T), tetrakis [methylene-3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate] methane (IRGANOX 1010) and n-octadecyl-3- (4'-hydroxy-3,5'-di-t-butylphenyl) propionate (IRGANOX 107)
A phenolic stabilizer represented by 6), bis (2,4-
Di-t-butylphenyl) pentaerythritol diphosphite or tris (2,4-di-t-butylphenyl)
Phosphite-based stabilizers represented by phosphites and the like; lubricants represented by higher fatty acid amides and higher fatty acid esters; glycerin esters and sorbitanate esters of fatty acids having 8 to 22 carbon atoms; antistatic agents such as polyethylene glycol esters; Silica, calcium carbonate, anti-blocking agent represented by talc, ethylene-α
-A polyethylene resin represented by an olefin copolymer, a low-density polyethylene, a high-density polyethylene, or the like may be added.

The processability improvers, stabilizers, lubricants, antiblocking agents and the like to be blended according to various purposes may be subjected to film processing after melt-kneading with the polypropylene resin composition of the present invention in advance. After dry blending, each may be made into a dry blend or one or more master batches and subjected to film processing, and any method may be used.

The above-mentioned polypropylene resin composition of the present invention is useful as a polypropylene resin composition for a T-die film and has an excellent appearance of a film obtained.

The T-die film processing apparatus used in the method for producing a T-die film of the present invention is not particularly limited, and examples thereof include a known T-die film processing apparatus and a known extrusion laminating apparatus. T
It is a die film processing device. As preferred film forming conditions in the method for producing a T-die film of the present invention, conditions of a resin temperature of 190 to 300 ° C and a cooling roll temperature of 20 to 50 ° C can be applied.

The T-die film obtained in the present invention is a T-die film comprising the above-mentioned polypropylene resin composition, and is a single-layer film or a multilayer film containing at least one layer comprising the polypropylene resin composition. There may be. The use of the film is not particularly limited. For example, the film can be used for food packaging such as bread and vegetables, clothing packaging such as shirts, industrial parts packaging, and the like. In addition, the film may be formed by a known technique such as a lamination method such as a dry laminating method or a sand laminating method. It can also be used as a film laminated on a base material such as resin or stretched polypropylene.

[0028]

Hereinafter, the present invention will be described based on examples.
The present invention is not limited by these examples. The evaluation method is as follows.

(1) Intrinsic viscosity of polymer (unit: dl /
g) Measurement was carried out at 135 ° C. in tetralin using an Ubbelohde viscometer. In addition, the intrinsic viscosity of the crystalline propylene polymer portion (b) in Reference Example 1 below was determined from the crystalline propylene polymer portion (a) and the intrinsic viscosity of the entire polymer using the calculation formula described in the specification. Was.

(2) Melt flow rate (MFR) Condition 14 of JIS K7210 (Condition Number 1)
Measured at 230 ° C. according to the method of 4). (Unit: g /
10 minutes)

(3) Die Swell Ratio (SR) The diameter of the cross section of the extrudate at the time of measuring the melt flow rate (MFR) according to the method of condition 14 of JIS K7210 was measured, and was determined from the following equation. Die swell ratio = diameter of cross section of extrudate / diameter of orifice However, cross section of extrudate refers to a cross section perpendicular to the extrusion direction of the extrudate, and when the cross section is not a perfect circle, the maximum diameter of the cross section The average of the values and the minimum was taken as the diameter of the cross section of the extrudate.

(4) Molecular weight and molecular weight distribution P. C. (Gel permeation chromatography) was measured under the following conditions. The molecular weight distribution was evaluated by the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn). Model: 150CV type (manufactured by Millipore Waters); Column: Shodex M / S 80; Measurement temperature: 145 ° C; Solvent: orthodichlorobenzene; Sample concentration: 5mg / 8mL; The calibration curve was prepared using standard polystyrene.

(5) Film Appearance The resulting film was visually evaluated for the sense of transparency.
The evaluation was evaluated as x when the film surface was roughened in a folded shape and the visibility was poor, and as ○ when the film surface was smooth and the visibility was excellent.

The polymers used in the examples and comparative examples are as follows. PP-1: Propylene-ethylene random copolymer manufactured by Sumitomo Chemical Co., Ltd., trade name Noblen WF577P
G2, lot number PIF129, MFR = 3, content of “repeating unit derived from ethylene” determined by infrared absorption spectrum = 4.0% by weight, SR = 1.16, molecular weight distribution (Mw / Mn) = 3.7, weight average molecular weight (M
w) = 1.2 × 10 ⁵ ; PP-2: propylene homopolymer obtained in Reference Example 1 below, MFR = 12, SR = 2.35, molecular weight distribution (M
w / Mn) = 8.0, weight average molecular weight (Mw) = 3.4
× 10 ⁵ ;

[Reference Example 1] (PP-2: Production of propylene homopolymer) [1] (Synthesis of solid catalyst component) After replacing a 200-liter SUS reaction vessel equipped with a stirrer with nitrogen, 80 liters of hexane was added. 6.55 mol of tetrabutoxytitanium, 2.8 mol of diisobutyl phthalate and 98.9 mol of tetraethoxysilane were added to form a homogeneous solution. Next, 51 l of a solution of butylmagnesium chloride in diisobutyl ether having a concentration of 2.1 mol / l was gradually dropped over 5 hours while maintaining the temperature in the reaction vessel at 5 ° C. After completion of the dropwise addition, the mixture was further stirred at room temperature for 1 hour, and then solid-liquid separated at room temperature.
Washing with 0 liter was repeated three times. Next, toluene was added so that the slurry concentration became 0.6 kg / liter, then a mixed solution of 8.9 mol of n-butyl ether and 274 mol of titanium tetrachloride was added, and 20.8 mol of phthalic acid chloride was further added. And stirred at 110 ° C. for 3 hours. Thereafter, solid-liquid separation was performed, and washing with 90 liters of toluene at 95 ° C. was performed twice. Next, after adjusting the slurry concentration to 0.6 kg / liter, 3.13 mol of diisobutyl phthalate, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was stirred at 105 ° C for 1 hour. After solid-liquid separation at the same temperature, 95
Washing with 90 liters of toluene at 2 ° C. was performed twice. Next, after adjusting the slurry concentration to 0.6 kg / liter, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was stirred at 95 ° C. for 1 hour.
Thereafter, solid-liquid separation was performed at the same temperature, and washing with 90 liters of toluene was performed three times at the same temperature. Next, after adjusting the slurry concentration to 0.6 kg / liter, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was stirred at 95 ° C. for 1 hour. Thereafter, solid-liquid separation was performed at the same temperature, and washing with 90 liters of toluene was performed at the same temperature.
The washing was repeated three times with 90 liters of hexane, and then dried under reduced pressure to obtain 11.0 kg of a solid catalyst component. The solid catalyst component was 1.9% by weight of titanium atom, 20% by weight of magnesium atom, 8.6% by weight of phthalate, 0.05% by weight of ethoxy group, 0.2% of butoxy group.
It contained 1% by weight and had good particle properties without fine powder.

[2] (Pre-activation of solid catalyst component) 1.5 liter of n-hexane, 37.5 mmol of triethylaluminum, dehydrated and sufficiently dehydrated in an autoclave with a stirrer made of SUS having an internal volume of 3 liters
t-butyl-n-propyldimethoxysilane 3.75
15 mmol of the solid catalyst component obtained in the above [1] was added thereto, and 15 g of propylene was continuously supplied over 30 minutes while maintaining the temperature in the tank at 5 to 15 ° C. to perform preactivation.

[3] (Polymerization of Crystalline Propylene Polymer Part (a)) In a SUS 300 liter polymerization tank, liquid propylene was maintained at a polymerization temperature of 60 ° C. and a polymerization pressure of 27 kg / cm ² G. While supplying at 57 kg / h,
1.3 mmol / h of triethylaluminum, 0.13 mmol / h of t-butyl-n-propyldimethoxysilane and 0.51 g / h of the solid catalyst component preactivated in the same manner as in the above [2] are continuously added. Propylene polymerization in the substantial absence of hydrogen,
(h) was obtained. At this time, the produced amount of the polymer was 3920 g per 1 g of the solid catalyst component, and as a result of sampling and analyzing a part thereof, the intrinsic viscosity was 7.7 dl / g. The obtained polymer was continuously transferred to the second tank as it was.

[4] (Polymerization of Crystalline Propylene Polymer Portion (b)) In a fluidized bed reactor with a stirrer having an internal volume of 1 m ³ (second tank), the polymerization temperature is 80 ° C., and the polymerization pressure is 18 kg / cm ^2.
G, the catalyst-containing polymer and triethylaluminum transferred from the first tank while supplying propylene and hydrogen so as to maintain a hydrogen concentration of 8 vol% in the gas phase.
By continuing propylene polymerization continuously while supplying 0 mmol / h and 6 mmol / h of t-butyl-n-propyldimethoxysilane, a polymer of 18.2 kg / h was obtained. The intrinsic viscosity of this polymer is 1.9 dl / g
Met. From the above results, the amount of polymer produced during the polymerization of (b) was 31760 g per 1 g of the solid catalyst component, and the polymerization weight ratio of the first tank and the second tank was 11:89,
The intrinsic viscosity of (b) was determined to be 1.2 dl / g.

[5] (Pelletization of polymer) For 100 parts by weight of this polymer powder, 0.1 part by weight of calcium stearate, Irganox 1010
0.05 parts by weight (manufactured by Ciba Geigy) and 0.2 parts by weight of Sumilyzer BHT (manufactured by Sumitomo Chemical Co., Ltd.) were added and melt-kneaded at 230 ° C., and the weight average molecular weight (Mw) was 3.4 × 10 ⁵ , molecular weight distribution (Mw / Mn) is 8.0,
A propylene homopolymer pellet having an MFR of 12 g / 10 min and a die swell ratio (SR) of 2.35 was obtained.

Example 1 A composition obtained by pellet blending 11 parts by weight of PP-2 with respect to 100 parts by weight of PP-1 was heated to a resin temperature of 230 to 270 ° C. using two 65 mmφ extruders and 90 mmφ extruders. The mixture was melt-kneaded under the following conditions, introduced into a feed block type T die (die width 1250 mm, lip opening 0.8 mm) heated to 225 ° C., and melt-extruded. The melt-extruded film was cooled and solidified by a cooling roll rotating at 100 m / min at a temperature controlled at 40 ° C. to obtain a single-layer unstretched film having a thickness of 60 μm. Evaluation results of the film appearance
○ The molecular weight distribution (Mw / Mn) measured using the obtained film as a sample was 3.5, and the weight average molecular weight (M
w) was 1.1 × 10 ⁴ .

[Comparative Example 1] Two PP-1s of 65 mmφ
Extruder and resin temperature 230-2 with 90mmφ extruder
The mixture was melt-kneaded under the condition of 70 ° C., introduced into a feed block type T die (die width 1250 mm, lip opening 0.8 mm) heated to 225 ° C., and melt-extruded.
The melt-extruded film is adjusted to a temperature of 40 ° C.
It was cooled and solidified by a cooling roll rotating at 0 m / min to obtain a single-layer unstretched film having a thickness of 60 μm.
The evaluation result of the film appearance was x. The molecular weight distribution (Mw / Mn) measured using the obtained film as a sample was 3.5, and the weight average molecular weight (Mw) was 1.1 × 10 ⁴ .

[0042]

As described in detail above, according to the present invention,
Even if T-die film processing is performed using a polypropylene resin having a narrow molecular weight distribution, a polypropylene resin capable of improving the above-described poor film appearance, a T-die film comprising the same, and a narrow polypropylene resin having a low molecular weight distribution , A method for producing a T-die film having improved film appearance defects as described above is provided.

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Claims (7)

[Claims] 1. A propylene polymer resin having a die swell ratio of less than 1.70 (A) 100 parts by weight and a propylene polymer resin having a die swell ratio of 1.80 or more (B) 0.01 to 0.01 parts by weight.
A polypropylene-based resin composition comprising 45 parts by weight. 2. The polypropylene resin composition according to claim 1, wherein the propylene polymer resin (A) has a die swell ratio of 1.00 to 1.60. 3. A process for producing a crystalline propylene polymer portion (a) having an intrinsic viscosity of 5.0 dl / g or more, wherein the propylene polymer resin (B) has an intrinsic viscosity of 3.0 dl / g.
Obtained by a polymerization method including a step of producing a crystalline propylene polymer portion (b) of less than 0.05, wherein the ratio of the crystalline propylene polymer portion (a) to the whole resin is 0.05 to 35.
The polypropylene resin composition according to claim 1 or 2, which is a propylene polymer having a limiting viscosity of less than 3.0 dl / g and a molecular weight distribution of less than 10 by weight. 4. The crystalline propylene polymer portion (a) and the crystalline propylene polymer portion (b) each have a content of a repeating unit derived from a propylene homopolymer or ethylene of 10% by weight or less. A random copolymer of propylene and ethylene, propylene having 4 to 12 carbon atoms and an α-olefin having 4 to 12 carbon atoms having a repeating unit content of 30% by weight or less.
When the content of a random copolymer with an olefin or a repeating unit derived from ethylene is 10% by weight or less and the content of a repeating unit derived from an α-olefin having 4 to 12 carbon atoms is 30% by weight or less. 3 of certain propylene, ethylene and α-olefin having 4 to 12 carbon atoms
The polypropylene resin composition according to claim 3, which is a random copolymer. 5. The polypropylene resin composition according to claim 1, wherein the polypropylene resin composition is a polypropylene resin composition for a T-die film. 6. A T-die film comprising the polypropylene resin composition according to claim 1. 7. A method for producing a T-die film, comprising using the polypropylene resin composition according to claim 1.