JP2010053342A - Polypropylene based resin composition, and film comprising it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene based resin composition being excellent in the balance of blocking-resistance, rigidity and low temperature impact-resistance and being further excellent in contamination-resistance of a processing machine. <P>SOLUTION: The polypropylene based resin composition contains a polypropylene based copolymer containing 50-95 wt.% of a polymer component (component A) in which a structural unit derived from propylene is a main component, and 5-50 wt.% of a polymer component (component B) of propylene, ethylene and 4 or more C α-olefin in which a content (X) of a structural unit derived from propylene is 10≤X<50 wt.%, a content (Y) of a structural unit derived from ethylene is 50<Y≤70 wt.%, and a content (Z) of a structural unit derived from the 4 or more C α-olefine is 0<Z≤20 wt.% (provided that the total of X, Y and Z is made to 100 wt.%), and hydrotalcite. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a polypropylene resin composition. More specifically, a polypropylene resin composition suitable as a material for a retort food packaging film that has an excellent balance between blocking resistance, rigidity, and impact at low temperatures, and also has excellent contamination resistance (cooling roll dirt) of processing machines. And a film made of the same.

Polypropylene is widely used in the field of packaging materials such as food packaging and fiber packaging because it is excellent in rigidity, heat resistance and packaging suitability. The packaging material is required to have rigidity, heat resistance, impact resistance at low temperatures, heat sealability, blocking resistance, and the like, and it is required to have less fish eyes and excellent appearance. In addition, large packaging bags are beginning to spread in retort food packaging and the like, and excellent impact resistance is required so that they can be used at low temperatures. In this case, it is conceivable to contain a large amount of an elastomer component, but it becomes difficult to achieve both blocking properties.

JP-A-9-20845 discloses a specific property of 0.01 to 1.0 part by weight of hydrotalcite and / or metal hydroxide compound as a neutralizing agent with respect to 100 parts by weight of crystalline polypropylene. The polypropylene resin composition for retort formed by blending 0.01 to 0.5 parts by weight of an organic inert substance having no fisheye, and has a good balance of anti-blocking property, transparency and slipperiness, In addition, a polypropylene resin composition for retort having good transparency after retort sterilization treatment and a retort-treated polypropylene film using the same are described.

JP-A-9-20846 discloses a specific property of 0.01 to 1.0 part by weight of hydrotalcite and / or metal hydroxide compound as a neutralizing agent with respect to 100 parts by weight of crystalline polypropylene. The polypropylene resin composition for retort formed by blending 0.01 to 0.8 parts by weight of the inorganic inactive substance having no fisheye, and has a good balance of antiblocking property, transparency and slipperiness, In addition, a polypropylene resin composition for retort having good transparency after retort sterilization treatment and a retort-treated polypropylene film using the same are described.

In JP-A-2002-194152, from 100 parts by weight of a polyolefin resin, 0.001 to 0.2 parts by weight of a neutralizing agent, and 0.01 to 1.0 parts by weight of phosphites having a specific structure. Preferably, the neutralizing agent is an inorganic neutralizing agent, more preferably the inorganic neutralizing agent is selected from hydrotalcite, an alkaline earth metal oxide or hydroxide. It is described that the polyolefin resin composition which is at least one kind is excellent in thermal stability during processing, stain resistance of the processing machine, corrosion resistance and color tone.

Japanese Patent Laid-Open No. 9-20845 Japanese Patent Laid-Open No. 9-20846 Japanese Patent Laid-Open No. 2002-194152

However, the above composition may be insufficient particularly in impact resistance at low temperatures, and is not satisfactory in the balance of blocking resistance, rigidity, and impact resistance at low temperatures.
An object of the present invention is to provide a polypropylene resin composition excellent in the balance between blocking resistance, rigidity, and impact resistance at low temperature, and further excellent in stain resistance of a processing machine, and a film comprising the same. It is in.

As a result of intensive studies, the present inventors have found that the present invention can solve the above problems, and have completed the present invention.

That is, the present invention has a polymer component (component A) of 50 to 95% by weight whose main component is a structural unit derived from propylene, and the content (X) of the structural unit derived from propylene is 10 ≦ X <50 weight. %, The content of structural units derived from ethylene (Y) is 50 <Y ≦ 70 wt%, and the content of structural units derived from α-olefins having 4 or more carbon atoms (Z) is 0 <Z ≦ 20% by weight (provided that the total of X, Y and Z is 100% by weight), and a structure derived from an α-olefin having 4 or more carbon atoms with respect to the content (X) of a structural unit derived from propylene Polypropylene copolymer containing 5 to 50% by weight of a polymer component (component B) of propylene, ethylene and an α-olefin having 4 or more carbon atoms, having a unit content (Z) weight ratio of 1 or less. And the polypropylene It relates polypropylene resin composition containing the hydrotalcite of 0.001 to 0.2 parts by weight per polymer 100 parts by weight.

ADVANTAGE OF THE INVENTION According to this invention, the polypropylene resin composition excellent in the balance with blocking resistance, rigidity, and impact resistance in low temperature and also excellent in the stain resistance of a processing machine can be obtained. And the polypropylene resin composition of this invention can be used suitably as a material of the film for retort food packaging.

The polypropylene resin composition of the present invention comprises a polymer component (component A) whose main component is a structural unit derived from propylene, and a polymer component (component B) of propylene, ethylene and an α-olefin having 4 or more carbon atoms. And a polypropylene resin composition containing hydrotalcite as essential components.

Here, the proportion of component A and component B in the polypropylene copolymer is in the range of 50 to 95% by weight of component A and 5 to 50% by weight of component B, preferably 60 to 95% by weight of component A. %, Component B is 5 to 40% by weight, more preferably component A is 60 to 90% by weight, and component B is 10 to 40% by weight. When component B is less than 5% by weight, impact resistance at low temperatures is poor, and when component B exceeds 50% by weight, blocking resistance may be deteriorated.

Component A is a polymer whose main component is a structural unit derived from propylene. From the viewpoint of rigidity, the melting point preferably exceeds 155 ° C, more preferably 160 ° C or higher. Component A may be copolymerized with an α-olefin such as ethylene or 1-butene within a range where the melting point does not become 155 ° C. or less, but is preferably a propylene homopolymer. When an α-olefin such as ethylene or 1-butene is copolymerized, the content of the structural unit derived from the α-olefin in the polymer component (component A) whose main component is the structural unit derived from propylene is 5% by weight or less, preferably 3% by weight or less (the polymer component mainly composed of propylene is 100% by weight). Although there is no restriction | limiting in particular about the intrinsic viscosity of the component A, the range of 1.5-3.0 dL / g is preferable, and the range of 1.5-2.5 dL / g is further more preferable.

The content (Y) of the structural unit derived from ethylene contained in Component B is 50 <Y ≦ 70 wt%, preferably 52 ≦ Y ≦ 70 wt%, more preferably 54 ≦ Y ≦ 70 wt%. % (However, the content of structural units derived from propylene contained in component B (X), the content of structural units derived from ethylene (Y), and the structural units derived from α-olefins having 4 or more carbon atoms) The total content (Z) is 100% by weight). When the content of the structural unit derived from ethylene is 50% by weight or less, or exceeds 70% by weight, impact resistance at low temperatures may be lowered.

The content (Z) of the structural unit derived from the α-olefin contained in Component B is 0 <Z ≦ 20 wt%, preferably 1 ≦ Z ≦ 16 wt%, more preferably 1 ≦ Z ≦ 10% by weight (provided that the content of structural units derived from propylene contained in component B (X), the content of structural units derived from ethylene (Y), and α-olefins having 4 or more carbon atoms) The total content of structural units (Z) is 100% by weight). When the content of the structural unit derived from α-olefin exceeds 0% by weight or 20% by weight, the impact resistance at low temperature may be lowered.

The weight ratio of the content (Z) of the structural unit derived from the α-olefin having 4 or more carbon atoms to the content (X) of the structural unit derived from propylene in the component B is 1 or less. When the weight ratio of the content (Z) of structural units derived from α-olefins having 4 or more carbon atoms to the content (X) of structural units derived from propylene is 1 or less, impact resistance at low temperatures Will improve.

Examples of the α-olefin having 4 or more carbon atoms contained in Component B include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinylcyclohexane, vinylnorbornane. 1-butene is preferable. Although there is no restriction | limiting in particular about the intrinsic viscosity of the component B, the range of 2.0-5.0 dL / g is preferable from a viewpoint of fish-eye generation | occurrence | production, and the range of 2.5-4.5 dL / g is further more preferable.

As a method for producing a polypropylene copolymer contained in the polypropylene resin composition of the present invention, after polymerizing a polymer component (component A) whose main component is a structural unit derived from propylene, propylene is continuously produced. And a method of polymerizing a polymer component (component B) of ethylene and an α-olefin having 4 or more carbon atoms, which can be produced by various polymerization methods using a normal stereoregular catalyst. it can.

Examples of the stereoregular catalyst include a catalyst comprising a solid titanium catalyst component, an organometallic compound catalyst component, and an electron donor used as necessary, and a transition of group IVB of the periodic table having a cyclopentadienyl ring. Examples include a catalyst system composed of a metal compound and an alkylaluminoxane, or a compound composed of a group IVB transition metal compound having a cyclopentadienyl ring and a compound which reacts with it to form an ionic complex and an organoaluminum compound. . Among them, a method of producing using a catalyst comprising a solid titanium catalyst component, an organometallic compound catalyst component, and an electron donor used as necessary is preferable.

Examples of the solid titanium catalyst component include a solid catalyst component precursor obtained by reducing a titanium compound with an organic magnesium compound in the presence of a silicon compound, a halogenated compound (for example, titanium tetrachloride), and an electron donor ( For example, a trivalent titanium compound-containing solid catalyst component obtained by contact treatment of an ether compound or a mixture of an ether compound and an ester compound) may be mentioned.

Examples of the organometallic compound catalyst component include an organoaluminum compound having at least one Al-carbon bond in the molecule, and a trialkylaluminum, a mixture of a trialkylaluminum and a dialkylaluminum halide, or an alkylalumoxane is preferable. In particular, triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, or tetraethyldialumoxane is preferable.

Examples of the electron donor include oxygen-containing compounds, nitrogen-containing compounds, phosphorus-containing compounds, and sulfur-containing compounds, among which oxygen-containing compounds or nitrogen-containing compounds are preferable, oxygen-containing compounds are more preferable, and alkoxysilicones or Ethers are particularly preferred.

Specifically, for example,
(A) In the coexistence of a silicon compound having a Si—O bond, the general formula Ti (OR ₁ ) _n X _4-n (R ₁ is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen electron, and n is 0 <Representing a number of n ≦ 4.) The solid product obtained by reducing the titanium compound represented by the organic magnesium compound is treated with a mixture of an ester compound, an ether compound and titanium tetrachloride. -Valent titanium compound-containing solid catalyst component,
(B) Organoaluminum compound (c) A catalyst system comprising a silicon compound having a Si—OR ₂ bond (R ₂ is a hydrocarbon group having 1 to 20 carbon atoms) can be mentioned.

Further, the molar ratio of Al atom in component (b) / Ti atom in component (a) is 1 to 2000, preferably 5 to 1500, and the molar ratio of Al atom in component (c) / component (b) is It is used so that it may become 0.02-500, preferably 0.05-50.

The polymerization method will be described below. The polymerization format may be either batch type or continuous type. Further, slurry polymerization or solution polymerization using an inert hydrocarbon solvent such as propane, butane, isobutane, pentane, hexane, heptane, and octane, and bulk polymerization or gas phase polymerization using a liquid olefin as a medium at the polymerization temperature are also possible. Although superposition | polymerization temperature can be implemented over -30-300 degreeC normally, 20-180 degreeC is preferable. Although there is no restriction | limiting in particular regarding the polymerization pressure, Generally the pressure of a normal pressure-10MPa, Preferably about 200kPa-5MPa is employ | adopted by the point that it is industrial and economical. In particular, the second step described later is preferably gas phase polymerization.
During polymerization, a chain transfer agent such as hydrogen can be added to adjust the molecular weight of the polymer.

Examples of the polypropylene copolymer contained in the polypropylene resin composition of the present invention include a method of producing by the following steps using the catalyst and the polymerization method.
Polymerization step 1: Propylene is homopolymerized to produce a polypropylene homopolymer component (component A), or propylene and an olefin selected from the group consisting of ethylene and an α-olefin having 4 to 10 carbon atoms. A step of copolymerization to produce a polymer component (component A) whose main component is a structural unit derived from propylene. Polymerization step 2: Mainly the structural unit derived from the polypropylene homopolymer component or propylene obtained in step 1 above. In the presence of a copolymer component as a component, propylene, ethylene and an α-olefin having 4 or more carbon atoms are copolymerized to form a polymer component (component) of propylene, ethylene and an α-olefin having 4 or more carbon atoms. B) generating step

A time for polymerizing a polymer component (component A) whose main component is a structural unit derived from propylene, and a time for polymerizing a polymer component (component B) of propylene, ethylene and an α-olefin having 4 or more carbon atoms; , The ratio of component A and component B can be changed.
In addition, by polymerizing a polymer component (component B) of propylene, ethylene and an α-olefin having 4 or more carbon atoms, by changing the gas composition in the mixed gas of propylene, ethylene and α-olefin, the component The composition of B can be changed.

In the polypropylene resin composition of the present invention, the polypropylene copolymer produced as described above may be a propylene homopolymer or an ethylene-α-olefin copolymer other than the polypropylene copolymer. Polymers can be included.

The hydrotalcite used in the present invention is an anion-exchangeable layered compound represented by the following general formula (I).
[M ²⁺ 1-XM ³⁺ X (OH) ₂ ] ^{X +} [A ^n- X / n · mH ₂ O] ^X- formula (I)
^{[M 2+ 1-XM 3+ X (} OH) 2 ] ^{X +} is a base layer, a _{^{[A n- X / n · mH 2}} O ] ^X- intermediate layer. M ²⁺ is a divalent metal cation such as Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ , and M ³⁺ is Al ³⁺ , Trivalent metal cations such as Fe ³⁺ , Cr ³⁺ , Co ³⁺ and In ³⁺ . A ^{n- is, OH -, F -, Cl} -, Br -, NO 3-, CO 3 2-, SO 4 2-, Fe (CN) 6 3-, CH 3 COO -, oxalic acid ion, Sarichin acid N-valent anions such as ions, where n is a positive integer. X is 0 <X ≦ 0.33, and m is a positive number. The hydrotalcite may be a natural mineral or a synthetic product, and can be used regardless of its crystal structure, crystal particle diameter, water content, surface treatment, and the like.

Among the hydrotalcites represented by the above general formula, the hydrotalcite represented by the following formula (II) is preferable.
_{M Y Al 2 (OH) 2Y} + 4 CO 3 · mH 2 O formula (II)
(In the formula, Y is Y ≧ 4, and m is a positive number.)

More preferably, M ²⁺ in the general formula (II) is composed of any one of Mg ²⁺ and Zn ²⁺ , or two divalent metal cations, and particularly preferably Hydrotalcite.
Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3H ₂ O
Mg _4.5 Al ₂ (OH) ₁₃ (CO ₃ ) _0.8 · O _0.2
Mg ₄ Al ₂ (OH) ₁₂ CO ₃ · 3H ₂ O
Mg ₅ Al ₂ (OH) ₁₄ CO ₃ / 4H ₂ O
Mg ₆ Al ₂ (OH) ₁₆ CO ₃ / 4H ₂ O (natural mineral)
Zn ₄ Al ₂ (OH) ₁₂ CO ₃ .mH ₂ O (m is 0 to 4)
Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ .mH ₂ O (m is 0 to 4)

The compounding quantity of the hydrotalcite used for this invention is 0.001-0.2 weight part with respect to 100 weight part of polypropylene-type copolymers. Preferably it is 0.001-0.1 weight part, More preferably, it is 0.005-0.05 weight part.

When the blending amount of the neutralizing agent is less than 0.001 part by weight, the catalyst residue is not sufficiently deactivated and the processing machine may be contaminated. When the amount exceeds 0.2 part by weight, the present invention The effect of saturates and becomes uneconomical.

The polypropylene resin composition of the present invention contains a neutralizing agent, an antioxidant, an ultraviolet absorber, an antistatic agent, an antifogging agent, a lubricant, an antiblocking agent, a nucleating agent and the like as long as the object of the present invention is not impaired. Can be contained.

The molded product can be obtained by molding the polypropylene resin composition of the present invention by a method that is usually used industrially. Examples thereof include an extrusion molding method, a blow molding method, an injection molding method, a compression molding method, and a calendar molding method.

The polypropylene resin composition of the present invention is preferably used for a film application by an extrusion molding method such as a T-die molding method or a tubular molding method. Particularly preferred is an unstretched film by the T-die method. The thickness of the film is preferably 10 to 500 μm, more preferably 10 to 100 μm. The film may be subjected to a surface treatment such as a corona discharge treatment, a flame treatment, a plasma treatment, an ozone treatment, etc. by a method that is usually employed industrially.

The use of the polypropylene resin composition of the present invention is preferably a film for retort food packaging that is heat-treated at a high temperature. The film is also preferably used as a single layer of a composite film. The composite film is a film composed of the film of the present invention and other films. Examples of the other films include a polypropylene biaxially stretched film, an unstretched nylon film, a stretched polyterephthalate film, and an aluminum foil. Examples of the method for producing the composite film include a dry laminating method and an extrusion laminating method.

Hereinafter, although the present invention is explained using an example and a comparative example, the range of the present invention is not limited only to an example. The detailed description of the invention and the measured values of each item in the examples and comparative examples were measured by the following methods.

(1) Melting point (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 held at 50 ° C. for 1 minute, and then the temperature was raised at 5 ° C./min. The temperature of the maximum peak of the obtained melting endothermic curve was defined as the melting point (Tm). Note that the melting point of indium (In) measured at a rate of temperature increase of 5 ° C./min using this measurement method was 156.6 ° C.

(2) MFR (unit: g / 10 minutes)
According to JIS K7210, measurement was performed at a temperature of 230 ° C. and a load of 2.16 kgf.

(3) Intrinsic viscosity ([η], unit: dL / g)
The measurement was performed in 135 ° C. tetralin using an Ubbelohde viscometer.

(4) Weight ratio χ (unit:% by weight) of component B to the entire polypropylene copolymer
Polymerization ratio: χ of the polymer component (component B) of propylene, ethylene, and α-olefin having 4 or more carbon atoms to the entire polypropylene copolymer containing component A and component B was calculated by the following method. .
χ = 1−ΔH _B / ΔH _A
ΔH _A : Polymer portion (component A) whose structural unit derived from propylene is the main component (component A) Heat of fusion of polymer after polymerization (J / g)
ΔH _B : Polymer component of propylene, ethylene and α-olefin having 4 or more carbon atoms (component B) Heat of fusion of polymer after polymerization (J / g)

(5) Content of structural unit derived from ethylene of component B (Y) and content of structural unit derived from 1-butene (Z) (unit: wt%)
Content of structural unit derived from ethylene (C2 ′ (T)) in polypropylene-based copolymer containing component A and component B and content of structural unit derived from 1-butene (C4 ′ (T) ) Was determined by the method described on pages 616 to 619 of the Polymer Analysis Handbook (1995, published by Kinokuniya Shoten).
Next, C2 ′ (T), C4 ′ (T) and χ described in the above (5) are derived from the content (Y) of structural unit derived from ethylene of component B and 1-butene by the following method. The content (Z) of the structural unit was calculated.
Y = C2 ′ (T) / χ × 100
Z = C4 ′ (T) / χ × 100

(6) Blocking resistance (unit: Kg / 12cm ² )
Using a 150 mm x 30 mm film (collected so that the film forming direction coincides with the long side direction), the films were overlapped, and a condition of condition was adjusted at 60 ° C for 24 hours by applying a load of 500 g to a range of 40 mm x 30 mm. Went. Thereafter, the sample was left in an atmosphere of 23 ° C. and 50% humidity for 30 minutes or more, peeled off 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.

(7) Rigidity (Young's modulus, unit: MPa)
Using an autostrain manufactured by Yasuda Seiki Seisakusho, under an atmosphere of 23 ° C. and a humidity of 50%, using a 120 mm × 30 mm film (collected so that the film forming direction (MD) and the long side direction coincide). A tensile test was performed at a grip interval of 60 mm and a tensile speed of 5 mm / min, and the initial elastic modulus was measured from the tangent at the zero point of the tensile-stress curve.

(8) Impact resistance (unit: kJ / m)
The film is placed in a thermostat set at a predetermined temperature (-10 ° C, -15 ° C), and the impact strength of the film is measured using a Toyo Seiki film impact tester with a hemispherical impact head having a diameter of 15 mm. Was measured.

(9) Contamination resistance of processing machines (cooling roll dirt test)
Using a 20 mm T die film forming apparatus (VS20-14 type, manufactured by Tanabe Plastics Machine Co., Ltd., with a 100 mm width T die), the resin was heated and melted at a resin temperature of 280 ° C., and the molten resin was extruded from the T die. This was cooled and solidified with a cooling roll (manufactured by SUS) at 30 ° C., and processed into a film having a width of about 7 cm and a thickness of 60 μm. This extrusion process was continued for 15 minutes, and then the dirt adhering to the cooling roll was wiped with a black cloth for 2 minutes while rotating the roll. For the determination of the degree of contamination, the degree of adherence of the white powdery adhering matter adhering to the black cloth was determined in five visual steps.
5: Extremely dirty.
4: Dirty.
3: Slightly dirty.
2: Slightly soiled.
1: Not dirty at all.

Reference Example 1 Production of Polypropylene Copolymer (BCPP1) [Preparation of Solid Components]
A 200 liter cylindrical reactor (with a stirrer having 3 pairs of stirring blades having a diameter of 0.35 m and 4 baffles having a width of 0.05 m and having a diameter of 0.5 m) was purged with nitrogen, and 54 liters of hexane, 780 g of diisobutyl phthalate, 20.6 kg of tetraethoxysilane and 2.23 kg of tetrabutoxy titanium were added and stirred. Next, 51 liters of dibutyl ether solution of butyl magnesium chloride (concentration 2.1 mol / liter) was dropped into the stirred mixture over 4 hours while maintaining the temperature in the reactor at 5 ° C. At this time, the rotational speed of stirring was 120 rpm. After completion of the dropwise addition, the mixture was stirred at 20 ° C. for 1 hour and filtered. The obtained solid was washed with 70 liters of toluene at room temperature three times, and toluene was added to obtain a solid component slurry.
The solid component contained Ti: 1.9% by weight, OEt (ethoxy group): 35.9% by weight, and OBu (butoxy group): 3.6% by weight. Moreover, the valence of the titanium atom in this solid component was trivalent.
[Synthesis of solid catalyst components]
After a 100 ml flask equipped with a stirrer, a dropping funnel and a thermometer was replaced with nitrogen, the solid component slurry obtained above was charged in an amount containing 8 g of the dry solid component, and the total volume of the slurry was 26. The supernatant liquid was extracted to 5 ml. A mixture of 16.0 ml of titanium tetrachloride and 0.8 ml of dibutyl ether was added at 40 ° C., and a mixture of 2.0 ml of phthalic acid chloride (hereinafter abbreviated as OPC) and 2.0 ml of toluene. Was added dropwise over 5 minutes. After completion of the dropwise addition, the reaction mixture was stirred at 115 ° C. for 4 hours. Thereafter, solid-liquid separation was performed at the same temperature, and washing was performed 3 times at 115 ° C. with 40 ml of toluene.
After washing, toluene was added so that the volume of the slurry was 26.5 ml. Thereto was added a mixture of 0.8 ml of dibutyl ether, 0.45 ml of diisobutyl phthalate and 6.4 ml of titanium tetrachloride, and the mixture was stirred at 105 ° C. for 1 hour. Thereafter, solid-liquid separation was performed at the same temperature, and washing was performed twice at 105 ° C. with 40 ml of toluene.
Next, toluene was added so that the volume of the slurry was 26.5 ml, and the temperature was 105 ° C. Thereto was added a mixture of 0.8 ml of dibutyl ether and 6.4 ml of titanium tetrachloride, and the mixture was stirred at 105 ° C. for 1 hour. Thereafter, solid-liquid separation was performed at the same temperature, and washing was performed twice at 105 ° C. with 40 ml of toluene.
Furthermore, toluene was added to 105 ° C. so that the volume of the slurry was 26.5 ml. Thereto was added a mixture of 0.8 ml of dibutyl ether and 6.4 ml of titanium tetrachloride, and the mixture was stirred at 105 ° C. for 1 hour. Thereafter, solid-liquid separation was performed at the same temperature, and washing was performed 6 times with 40 ml of toluene at 105 ° C. and 3 times with 40 ml of hexane at room temperature. This was dried under reduced pressure to obtain a solid catalyst component.
The solid catalyst component contained 1.6% by weight of titanium atoms, 7.6% by weight of diethyl phthalate, 0.8% by weight of ethyl normal butyl phthalate, and 2.5% by weight of diisobutyl phthalate.
[Preliminary polymerization]
To a SUS autoclave with a stirrer with an internal volume of 3 L, 1.5 L of fully dehydrated and degassed n-hexane, 30 mmol of triethylaluminum, 3.0 mmol of cyclohexylethyldimethoxysilane and 16 g of the above solid catalyst component were added, After preliminarily polymerizing 32 g of propylene while continuously maintaining the temperature in the autoclave at about 3 to 20 ° C. over about 40 minutes, the prepolymerized slurry was transferred to a 200-liter SUS autoclave with a stirrer. Then, 132 L of liquid butane was added to prepare a slurry of a prepolymerized catalyst component.
Polymerization of component A [polymerization step (1)]
A slurry of propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane and a prepolymerization catalyst component is continuously fed using a vessel type reactor with an internal volume of 40 L with a stirrer, the polymerization temperature is set to 78 ° C., and the stirring speed is 150 rpm. The reactor liquid level is maintained at 18 L, the propylene feed rate is 25 kg / hr, the hydrogen feed rate is 20 NL / hr, the triethylaluminum feed rate is 41 mmol / hr, and the cyclohexylethyldimethoxysilane feed rate. Was 6.15 mmol / hour, and the amount of slurry of the prepolymerized catalyst component was 0.57 g / hour in terms of solid catalyst component, and continuous polymerization was conducted for 0.26 hours. The polymer was discharged at 2.6 kg / hour.
[Polymerization step (2)]
The slurry discharged from the polymerization step (1) is continuously transferred to a vessel type reactor different from the polymerization step (1), propylene and hydrogen are continuously supplied, the polymerization temperature is set to 73 ° C., and stirring is performed. Continuous polymerization was performed for 0.45 hours at a speed of 150 rpm, a reactor liquid level of 44 L, a propylene supply rate of 15 kg / hour, and a hydrogen supply rate of 11 NL / hour. The polymer was discharged at 3.0 kg / hour.
[Polymerization step (3)]
The slurry discharged from the polymerization step (2) is continuously transferred to a vessel type reactor different from the polymerization steps (1) and (2), the polymerization temperature is set to 68 ° C., the stirring speed is set to 150 rpm, and the reactor The liquid level was maintained at 44 L, and continuous polymerization was further performed for 0.49 hours. The polymer was discharged at 2.6 kg / hour.
[Polymerization step (4)]
The slurry discharged from the polymerization step (3) is continuously transferred to a fluidized bed reactor equipped with a stirrer with an internal volume of 1 m ³ , propylene and hydrogen are continuously supplied, the polymerization temperature is set to 80 ° C., and the polymerization pressure is increased. The polymerization was carried out for 2.9 hours at a pressure ratio of 1.8 MPa and a propylene / hydrogen concentration ratio in the reactor gas of 98.94 vol% / 1.06 vol% (propylene concentration / hydrogen concentration). The polymer was discharged at 11.0 kg / hour. The intrinsic viscosity [η] A of the obtained polymer component (component A) was 1.80 dL / g.
Polymerization of component B [polymerization step (5)]
The polymer component (component A) discharged from the polymerization step (4) is continuously transferred to a fluidized bed reactor with a stirrer having an internal volume of 1 m ³ different from the reactor used in the polymerization step (4). Propylene, ethylene, 1-butene and hydrogen are continuously fed, the polymerization temperature is 70 ° C., the polymerization pressure is 1.4 MPa, and the concentration ratio of propylene, ethylene, 1-butene and hydrogen in the reactor gas is 42.65% by volume / 48% by volume / 6.1% by volume / 3.25% by volume (propylene concentration / ethylene concentration / 1-butene concentration / hydrogen concentration) and supplying triethyl as a deactivator Polymerization was carried out for 1.7 hours with a molar ratio to aluminum of 0.025. The polymer was discharged at 5.1 kg / hour. The intrinsic viscosity [η] B of the obtained polymer component (component B) was 2.89 dL / g.
Table 1 shows the analysis results of each component of the produced polypropylene copolymer.

Reference Example 2 Production of Polypropylene Copolymer (BCPP2) The solid catalyst component and prepolymerization were carried out in the same steps as in Reference Example 1.
Polymerization of component A [polymerization step (1)]
A slurry of propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane and a prepolymerization catalyst component is continuously fed using a vessel type reactor with an internal volume of 40 L with a stirrer, the polymerization temperature is set to 78 ° C., and the stirring speed is 150 rpm. The reactor liquid level was maintained at 18 L, the propylene feed rate was 25 kg / hr, the hydrogen feed rate was 20 NL / hr, the triethylaluminum feed rate was 42 mmol / hr, and the cyclohexylethyldimethoxysilane feed rate. Continuous polymerization was carried out for 0.26 hours by setting the amount to 6.3 mmol / hour and setting the supply amount of the prepolymerized catalyst component slurry to 0.57 g / hour in terms of solid catalyst component. The polymer was discharged at 2.5 kg / hour.
[Polymerization step (2)]
The slurry discharged from the polymerization step (1) is continuously transferred to a vessel type reactor different from the polymerization step (1), propylene and hydrogen are continuously supplied, the polymerization temperature is set to 73 ° C., and stirring is performed. The speed was 150 rpm, the reactor liquid level was maintained at 44 L, the propylene feed rate was 15 kg / hr, the hydrogen feed rate was 11 NL / hr and continuous polymerization was conducted for an additional 0.45 hours. The polymer was discharged at 3.1 kg / hour.
[Polymerization step (3)]
The slurry discharged from the polymerization step (2) is continuously transferred to a vessel type reactor different from the polymerization steps (1) and (2), the polymerization temperature is set to 68 ° C., the stirring speed is set to 150 rpm, and the reactor The liquid level was maintained at 44 L, and continuous polymerization was further performed for 0.49 hours. The polymer was discharged at 2.7 kg / hour.
[Polymerization step (4)]
The slurry discharged from the polymerization step (3) is continuously transferred to a fluidized bed reactor equipped with a stirrer with an internal volume of 1 m ³ , propylene and hydrogen are continuously supplied, the polymerization temperature is set to 80 ° C., and the polymerization pressure is increased. The pressure was 1.8 MPa, and the concentration ratio of propylene and hydrogen in the reactor gas was 98.91 vol% / 1.09 vol% (propylene concentration / hydrogen concentration), and polymerization was carried out for 2.9 hours. The polymer was discharged at 10.9 kg / hour. The intrinsic viscosity [η] A of the obtained polymer component (component A) was 1.80 dL / g.
Polymerization of component B [polymerization step (5)]
The polymer component (component A) discharged from the polymerization step (4) is continuously transferred to a fluidized bed reactor with a stirrer having an internal volume of 1 m ³ different from the reactor used in the polymerization step (4). Propylene, ethylene and hydrogen are continuously supplied, the polymerization temperature is 70 ° C., the polymerization pressure is 1.4 MPa, and the concentration ratio of propylene, ethylene and hydrogen in the reactor gas is 74.72% by volume / 24% by volume. /1.28 vol% (propylene concentration / ethylene concentration / hydrogen concentration), oxygen was added as a quenching agent at a molar ratio of 0.017 to the supplied triethylaluminum, and polymerization was carried out for 1.9 hours. The polymer was discharged at 5.0 kg / hour. The intrinsic viscosity [η] B of the obtained polymer component (component B) was 2.57 dL / g.
Table 1 shows the analysis results of each component of the produced polypropylene polymer.

Example 1
[Η] is 1.84 dL / g, 120 g of homopolypropylene having a melting point of 164.7 ° C., 380 g of a polypropylene copolymer (BCPP1), hydrotalcite (DHT4C, manufactured by Kyowa Chemical Industry Co., Ltd.) 05 g, Sumiser GP (2,4,8,10-tetra-tert-butyl-6- [3- (3-methyl-4-hydroxy-5-tert-butylphenyl) propoxy] dibenzo [d, f] [1 , 3, 2] Dioxaphosphepine, manufactured by Sumitomo Chemical Co., Ltd. (0.25 g) was mixed, and a 20 mm single screw extruder (VS20-14 type, manufactured by Tanabe Plastics Machinery Co., Ltd., L / D = 12. 6 with a full flight type screw) was melt-kneaded at 250 ° C. to obtain a polypropylene resin composition having MFR = 3.1 (g / 10 min).
The obtained polypropylene resin composition was melt-extruded at a resin temperature of 280 ° C. using a 20 mmT die film forming apparatus (VS20-14 type, manufactured by Tanabe Plastics Machine Co., Ltd., with a 100 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. The properties of the obtained film are shown in Table 2.
Furthermore, the cooling roll dirt was evaluated using the obtained polypropylene resin composition. The results are shown in Table 2.

Example 2
A polypropylene resin with MFR = 3.1 (g / 10 min) was carried out in the same manner as in Example 1 except that the amount of hydrotalcite (DHT4C, manufactured by Kyowa Chemical Industry Co., Ltd.) was changed to 0.25 g. A composition was obtained. Table 2 shows the characteristics of the obtained film and the results of cooling roll contamination.

Comparative Example 1
Polypropylene with MFR = 3.1 (g / 10 min), which was carried out in the same manner as in Example 1 except that 0.25 g of calcium stearate was used instead of hydrotalcite (DHT4C, manufactured by Kyowa Chemical Industry Co., Ltd.). A system resin composition was obtained. Table 2 shows the characteristics of the obtained film and the results of cooling roll contamination.

Comparative Example 2
[Η] is 1.84 dL / g, melting point is 164.7 ° C., 115 g of homopolypropylene, 385 g of polypropylene resin composition (BCPP2), hydrotalcite (DHT4C, manufactured by Kyowa Chemical Industry Co., Ltd.) 05 g, Sumiser GP (2,4,8,10-tetra-tert-butyl-6- [3- (3-methyl-4-hydroxy-5-tert-butylphenyl) propoxy] dibenzo [d, f] [1 , 3, 2] Dioxaphosphepine, manufactured by Sumitomo Chemical Co., Ltd. (0.25 g) was mixed, and a 20 mm single screw extruder (VS20-14 type, manufactured by Tanabe Plastics Machinery Co., Ltd., L / D = 12. 6 with a full flight type screw) was melt-kneaded at 250 ° C. to obtain a polypropylene resin composition having MFR = 3.2 (g / 10 min).
The obtained polypropylene resin composition was melt-extruded at a resin temperature of 280 ° C. using a 20 mmT die film forming apparatus (VS20-14 type, manufactured by Tanabe Plastics Machine Co., Ltd., with a 100 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. The properties of the obtained film are shown in Table 2.
Furthermore, the cooling roll dirt was evaluated using the obtained polypropylene resin composition. The results are shown in Table 2.

Table 1

Table 2

Claims (3)

50 to 95% by weight of a polymer component (component A) having a structural unit derived from propylene as a main component, and the content (X) of the structural unit derived from propylene is 10 ≦ X <50% by weight,
The content (Y) of the structural unit derived from ethylene is 50 <Y ≦ 70% by weight,
The content (Z) of the structural unit derived from the α-olefin having 4 or more carbon atoms is 0 <Z ≦ 20% by weight (provided that the total of X, Y and Z is 100% by weight),
The weight ratio of the content (Z) of the structural unit derived from the α-olefin having 4 or more carbon atoms to the content (X) of the structural unit derived from propylene is 1 or less.
A polypropylene copolymer comprising 5 to 50% by weight of a polymer component (component B) of propylene, ethylene and an α-olefin having 4 or more carbon atoms,
And a polypropylene resin composition containing 0.001 to 0.2 parts by weight of hydrotalcite with respect to 100 parts by weight of the polypropylene copolymer. The polypropylene resin composition according to claim 1, wherein the α-olefin having 4 or more carbon atoms is 1-butene. The film which consists of a polypropylene resin composition in any one of Claim 1 or 2.