JP3024082B2 - Propylene-based polymer blend and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a propylene-based polymer blend, and more particularly, to a propylene-based polymer blend excellent in transparency, whitening resistance and low-temperature impact resistance, and a method for producing the same by gas-phase polymerization. About.

[0002]

2. Description of the Related Art Polypropylene resin is relatively inexpensive,
Due to their excellent thermal and mechanical properties, they are used today in a wide variety of fields. However, while propylene homopolymer generally has high rigidity,
Poor impact resistance, especially at low temperatures. As a propylene homopolymer having improved impact resistance at low temperatures, a propylene block copolymer composition in which a propylene homopolymer component is first formed, and then an ethylene-propylene random copolymer component is formed. It is widely used in various industrial fields such as home electric appliances field.

[0003] These conventionally used propylene-based block copolymer compositions are excellent in impact resistance, but are inferior in transparency as compared with homopolymers, and are largely whitened when subjected to impact. . As a method of improving the disadvantage of impact whitening of the propylene-based block copolymer composition, a method of increasing the content of ethylene in the copolymer so far,
A method of adding polyethylene to a propylene-based block copolymer composition has been proposed. Both methods are excellent methods for improving the impact whitening property, but at the same time, the transparency of the product is reduced.

JP-A-5-331327 discloses a polymer composition containing a propylene block copolymer composition in which only the limiting viscosity ratio of a propylene homopolymer component and an ethylene-propylene random copolymer component is specified. JP
No. 6-145268 discloses a polymer composition that defines the intrinsic viscosity of a propylene homopolymer component, and the intrinsic viscosity ratio to the intrinsic viscosity of an ethylene-propylene copolymer component and the ethylene content of an ethylene-propylene random copolymer component. Has been proposed. JP-A-56-72042 and JP-A-57-63350 disclose polyolefin resin compositions in which an ethylene / propylene copolymer containing a small amount of ethylene and an ethylene / propylene copolymer are blended. are doing.

[0005]

The impact whitening property and the transparency of the injection-molded articles of these polymer compositions from the measurement results of the haze were improved as compared with the conventional propylene-based polymer blends, but were further improved. There is room for In addition, the adoption of the blending process may cause variations in various characteristics due to variations in the dispersibility of each component in the final product.

An object of the present invention is to provide a propylene-based polymer blend excellent in balance among various properties such as transparency, whitening resistance and impact resistance at low temperature, and a method for producing the same.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that a propylene-α-olefin random copolymer (A) and this random copolymer
(A) and a propylene-based polymer blend comprising a propylene-α-olefin random copolymer (B) having a different α-olefin content, the intrinsic viscosity of the propylene-α-olefin random copolymer (B), When the intrinsic viscosity ratio of both copolymers and the product of the intrinsic viscosity ratio and the weight ratio of both copolymers are within a certain range, the balance of transparency, whitening resistance and low-temperature impact resistance is excellent. Thus, the present invention has been completed.

According to the present invention, the propylene content is 90 to 99.
A propylene-α-olefin random copolymer (A) having a propylene content of 55 to 90% by weight and a propylene-α-olefin random copolymer (B) having a propylene content of 55 to 90% by weight. Copolymer
(B) intrinsic viscosity [η] _B is 1.3 to 3.5 dl / g, intrinsic viscosity ratio of propylene-α-olefin copolymer (B) and propylene-α-olefin copolymer (A) [ η] _B / [η] _A is 0.5 to 1.3, and the intrinsic viscosity ratio of the propylene-α-olefin copolymer (A) and the propylene-α-olefin copolymer (B) is [η] _B / [eta] _a and a weight ratio W _a / W _B and the product _{([η] B / [η} ] a) · (W a / W B) to be in the range of 1.0 to 4.5 A propylene-based polymer blend characterized by the following:

In another aspect of the present invention, the average particle size is 20 to 3
00 μm titanium-containing solid catalyst component, general formula AlR ¹ _m X
_An organoaluminum compound represented by _3-m (wherein, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a halogen atom, and m is a positive number satisfying 3 ≧ m> 1.5) And R ² _X R ³ _Y Si (OR ⁴ ) _Z , wherein R ² and R ⁴ are a hydrocarbon group, R ³ is a hydrocarbon group or a hydrocarbon group containing a hetero atom, and 0 ≦ X ≦ 2, 1 ≦ Y ≦ 3, 1 ≦ Z ≦ 3 and X
+ Y + Z = 4) propylene and an α-olefin other than propylene are copolymerized in the gas phase in the presence of a stereoregular catalyst comprising an organosilicon compound represented by the formula: % Propylene-α-
A first polymerization step for producing an olefin random copolymer (A), and then copolymerizing propylene and an α-olefin other than propylene with a different composition ratio from the first polymerization step;
The method for producing a propylene-based polymer blend described above, wherein the propylene-based polymer blend is continuously performed in the order of the second polymerization step for producing a propylene-α-olefin random copolymer (B) having a total weight of 10 to 50% by weight. .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the propylene polymer blend of the present invention, the propylene-α-olefin random copolymer (A) has a propylene content of 90 to 99% by weight.
Is a random copolymer of propylene and an α-olefin other than propylene. When the propylene content of the copolymer (A) is too small, the heat resistance of the molded article is reduced, while when it is too large, the whitening resistance becomes insufficient. The propylene content of the copolymer (A) is preferably from 92 to 99% by weight.

As the α-olefin component of the propylene-α-olefin random copolymer (A), ethylene, 1-
Butene, 1-pentene, 1-hexene, 1-octene,
1-decene, 1-dodecene, 4-methyl-1-pentene, 3-methyl-1-pentene, and the like,
Ethylene is preferred in terms of production cost.

The other component of the propylene-based polymer blend, a propylene-α-olefin random copolymer (B)
Is a random copolymer of propylene having a propylene content of 55 to 90% by weight and an α-olefin other than propylene. When the propylene content of the copolymer (B) is excessive, the impact resistance of the molded article at low temperature becomes insufficient,
If it is too small, the transparency will decrease. The preferred propylene content of the copolymer (B) is 55 to 85% by weight.
Α of propylene-α-olefin random copolymer (B)
Examples of the olefin component include the same compounds as those of the copolymer (A), and ethylene is also preferred here.

The propylene-α-olefin random copolymer (B) has an intrinsic viscosity [η] _B measured in tetralin at 135 ° C. of 1.3 to 3.5 dl / g, more preferably 1.5 to 3.5 dl / g.
In the range of 3.0 dl / g, the intrinsic viscosity ratio [η] _B / [η] _A to the intrinsic viscosity [η] _A of the propylene-α-olefin random copolymer (A) measured under the same conditions is 0. .5-
1.3, preferably in the range of 0.6 to 1.2. Intrinsic viscosity of propylene-α-olefin random copolymer (B)
Since [η] _B cannot be measured directly, the intrinsic viscosity of the propylene-α-olefin random copolymer (A), which can be measured directly,
[η] _A and intrinsic viscosity of the final product propylene-based polymer blend [η] _WHOLE , and propylene-α
- the weight% W _B of olefin random copolymer (B),
It is calculated by the following equation. _{[η] B = {[η} ] WHOLE - (1-W B / 100) [η] A} / (W B / 100)

[0014] The intrinsic viscosity [η] _B of the propylene-α-olefin random copolymer (B) affects the molding cycle property and the transparency of the molded product, and is different from that of the propylene-α-olefin random copolymer (B). The intrinsic viscosity ratio [η] _B / [η] _A with the propylene-α-olefin random copolymer (A) is the propylene-α-olefin random copolymer of the propylene-α-olefin random copolymer (B). It affects the dispersibility in (A). As the intrinsic viscosity [η] _{B of the} propylene-α-olefin random copolymer (B) increases, the molding cycleability decreases. Further, if the intrinsic viscosity ratio with propylene-α-olefin random (A) is too large, transparency is reduced,
If it is too small, the impact resistance at low temperatures is insufficient, and the desired properties cannot be achieved.

In the propylene-based polymer blend of the present invention, the propylene-α-olefin random copolymer
(A) and propylene-α-olefin random copolymer
The weight ratio W _A / W _B with (B) is the product of the intrinsic viscosity ratio [η] _B / [η] _{A of} both copolymers, ([η] _B / [η] _A ) · ( W _A / W
_B ) is a ratio in the range of 1.0 to 4.5. The product of the weight ratio of the two copolymers and the intrinsic viscosity ratio is an index indicating the whitening resistance of the composition.When the value is small, the whitening resistance is improved, but the decrease in heat resistance and rigidity is large. On the other hand, when it is larger, the intended effect of improving the whitening resistance cannot be obtained.
The specific composition of the propylene-based polymer blend is 90 to 50% by weight of the propylene-α-olefin random copolymer (A) and 10 to 50% by weight of the propylene-α-olefin random copolymer (B) based on the weight of the polymer blend. % By weight.

The propylene-based polymer blend of the present invention that satisfies the above-mentioned various properties can be suitably used as a raw material for producing molded articles having excellent transparency, whitening resistance and low-temperature impact resistance.

The propylene-based polymer blend of the present invention may be produced by any method as long as it satisfies the above-mentioned properties, but is preferably produced by employing the above-mentioned two-stage continuous polymerization method in the gas phase. be able to.

The two-stage continuous polymerization method has an average particle size of 20 to
In the presence of a stereoregular catalyst in which a 300 μm titanium-containing solid catalyst component, an organoaluminum compound, and an organosilicon compound are combined, propylene and an α-olefin other than propylene are copolymerized in a gas phase to a predetermined amount and A first polymerization step for producing a propylene-α-olefin random copolymer (A) having a predetermined composition ratio, and then copolymerizing propylene and α-olefins other than propylene by changing their composition ratios to obtain the remaining The second polymerization step for producing the propylene-α-olefin random copolymer (B) is sequentially and continuously performed.

In the above-mentioned production method, the titanium-containing solid catalyst component is obtained by supporting a titanium compound on an inorganic carrier such as a magnesium compound, a silica compound or alumina or an organic carrier such as polystyrene or the like. Those having an average particle diameter in the range of 20 to 300 μm obtained by reacting an electron donating compound such as ethers and esters can be used, including known catalysts.

For example, a titanium-containing solid catalyst component obtained by spray-granulating a magnesium compound-alcohol solution to partially dry a solid component and then treating the dried solid component with a titanium halide and an electron donating compound (JP-A-3-119003) Publication), a magnesium compound dissolved in tetrahydrofuran / alcohol / electron donor, and a magnesium-containing carrier precipitated with TiCl ₄ alone or in combination with an electron donor, and further treated with a titanium halide and an electron-donating compound to obtain a titanium-containing solid. And a catalyst component (JP-A-4-103604).

The titanium-containing catalyst component has an average particle size of 20 to
Those having a thickness of 300 μm, preferably 20 to 150 μm are used. If the average particle size of the titanium-containing catalyst component is too small, the fluidity of the powder of the resulting propylene-based polymer blend will be significantly impaired, causing contamination in the polymerization system due to adhesion to the vessel walls of the polymerization vessel, stirring blades, etc. Transport of the powder discharged from the tank becomes difficult, and the stable operation is greatly hindered. Further, the titanium-containing catalyst component preferably has a particle size distribution in which uniformity in a normal distribution is 2.0 or less. If the degree of uniformity increases, the powder fluidity of the propylene-based polymer blend deteriorates, and continuous stable operation becomes difficult.

As the organoaluminum compound, the general formula is AlR ¹ _m X _3-m (wherein R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a halogen atom, and m represents 3 ≧ m> 1). (A positive number of 0.5) can be used.

Specifically, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, tri-i-butylaluminum, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum sesquichloride, di-aluminum n-propylaluminum monochloride,
Examples thereof include ethylaluminum sesquichloride, diethylaluminum iodide, and ethoxydiethylaluminum. Preferably, triethylaluminum is used. These organoaluminum compounds can be used alone or as a mixture of two or more.

As the organosilicon compound, a compound represented by the general formula R ² _X R
³ _Y Si (OR ⁴ ) _Z (wherein R ² and R ⁴ are hydrocarbon groups, R ³
Represents a hydrocarbon group or a hydrocarbon group containing a hetero atom, and 0 ≦ X ≦ 2, 1 ≦ Y ≦ 3, 1 ≦ Z ≦ 3 and X + Y +
Z = 4) is used.

Specifically, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, phenylmethyldimethoxysilane, t-butyltrimethoxysilane, t-butyltriethoxysilane, phenyltriethoxysilane, methylethyl Dimethoxysilane, methylphenyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, di-t-butyldimethoxysilane, diphenyldimethoxysilane, trimethylmethoxysilane, cyclohexylmethyldimethoxysilane, trimethylethoxysilane And the like. Preferably, diisobutyldimethoxysilane, diisopropyldimethoxysilane,
Di-t-butyldimethoxysilane, cyclohexylmethyldimethoxysilane and diphenyldimethoxysilane are used. These organosilicon compounds can be used alone or as a mixture of two or more.

The stereoregular catalyst obtained by combining the titanium-containing solid catalyst component, the organoaluminum compound and the organosilicon compound is used for the copolymerization of propylene with an α-olefin other than propylene in the first polymerization step. It is preferable to use the catalyst after preliminarily activating the α-olefin by preliminarily reacting it with the catalyst.

The pre-activation treatment of the titanium-containing solid catalyst component can be carried out in the presence or absence of the same organic aluminum compound as that used in the main polymerization. The organoaluminum compound is used in an amount of 0.1 to 4 per mole of atom.
0 mol, preferably in the range of 0.3 to 20 mol,
0.1 to 100 g, preferably 0.5 to 50 g, of the α-olefin is reacted per 1 g of the titanium-containing solid catalyst component at 0 to 80 ° C. for 10 minutes to 48 hours.
A preferred organoaluminum compound is triethylaluminum.

In the preliminary activation treatment, the same organosilicon compound as the organosilicon compound used in the main polymerization is used in an amount of 0.01 to 1 mol per mol of the organoaluminum compound.
0 mol, preferably in the range of 0.05 to 5 mol. Preferred organosilicon compounds are diisobutyldimethoxysilane, diisopropyldimethoxysilane, di-
t-butyldimethoxysilane, cyclohexylmethyldimethoxysilane and diphenyldimethoxysilane.

The α-olefin used in the preactivation treatment of the titanium-containing solid catalyst component is ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, -Tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 4-methyl-1-pentene, 3-methyl-1-pentene, and the like. It may be a mixture. In addition, a molecular weight regulator such as hydrogen can be used in combination to regulate the molecular weight of the polymer formed during the polymerization.

The inert solvent used for the pre-activation treatment of the titanium-containing solid catalyst component is a liquid saturated hydrocarbon such as hexane, heptane, octane, decane, dodecane and liquid paraffin, or a silicon oil having a structure of dimethylpolysiloxane. It is an inert solvent that does not significantly affect the isomerization reaction. These inert solvents may be either a single solvent or a mixture of two or more solvents. When using such an inert solvent, it is preferable to use it after removing impurities such as water and sulfur compounds which adversely affect the polymerization.

In the process for producing a propylene-based polymer blend of the present invention, propylene and an α-olefin other than propylene are copolymerized in the gas phase in the presence of the titanium-containing solid catalyst component preactivated by the above-mentioned method. The first polymerization step is followed by a second polymerization step in which the propylene content is changed to copolymerize propylene with an α-olefin. The first polymerization step is not limited to gas-phase polymerization, and may be slurry polymerization or bulk polymerization.However, since the subsequent second polymerization step is preferably gas-phase polymerization, in the present invention, The first polymerization step also employs gas phase polymerization. When slurry polymerization or bulk polymerization is employed as the second polymerization step, the copolymer elutes into the solution, making it difficult to continue stable operation.

The polymerization conditions for the propylene-α-olefin random copolymer (A) vary depending on the type of polymerization. In the case of the gas phase polymerization method, a titanium-containing solid catalyst which has been preactivated by mixing and stirring a certain amount of powder. Polymerization temperature in the presence of a stereoregular catalyst consisting of a component, an organoaluminum component and an organosilicon compound, at a polymerization temperature of 20 to 120C, preferably 40 to 1
00 ° C., polymerization pressure from atmospheric pressure to 9.9 MPa, preferably 0.1 MPa.
Propylene and an α-olefin other than propylene are supplied under the conditions of 59 to 5.0 MPa to polymerize the propylene-α-olefin random copolymer (A). Usage rate of organoaluminum compound and titanium-containing solid catalyst component (molar ratio)
Is Al / Ti = 1 to 500, preferably 10 to 300. In this case, the number of moles of the titanium-containing solid catalyst component is
It refers to the substantial number of Ti gram atoms present in the titanium-containing solid catalyst component.

The use ratio (molar ratio) of the organosilicon compound and the organoaluminum component is Al / Si = 1 to 10, preferably 1.5 to 8. When the Al / Si molar ratio is excessive, the low crystalline component of the propylene-α-olefin random copolymer (A) increases, the rigidity of the propylene-based polymer blend becomes insufficient, and the fluidity of the powder decreases. It is difficult to maintain stable operation. On the other hand, when the Al / Si molar ratio is too small, the polymerization activity is remarkably reduced, and the productivity is reduced.

In controlling the molecular weight of the propylene-α-olefin random copolymer (A), a molecular weight regulator such as hydrogen can be used during polymerization, and the propylene-α-olefin random copolymer (A) can be used. Is carried out so as to satisfy the requirements of the present invention. After polymerization of the propylene-α-olefin random copolymer (A), a part of the produced powder was extracted, and the intrinsic viscosity ([η] _A ), melt flow rate (MFR _A ) and polymerization yield per unit weight of the catalyst were determined. Provide for measurement.

Following the polymerization of the propylene-α-olefin random copolymer (A) in the first polymerization step, the polymerization temperature is from 20 to 120 ° C., preferably from 40 to 100 ° C., and the polymerization pressure is from atmospheric pressure to 9.9 MPa, preferably. Is 0.59-5.0MP
Under the conditions of a, the composition ratio of the mixed monomer of propylene and α-olefin other than propylene is changed from that of the first polymerization step to copolymerize to form a propylene-α-olefin random copolymer (B). Perform two polymerization steps. Α in the propylene-α-olefin random copolymer (B)
The olefin unit content is controlled by controlling the gas molar ratio of the α-olefin monomer and the propylene monomer in the comonomer gas so that the α-olefin unit content in the copolymer is 10%.
Adjust to ~ 45% by weight.

On the other hand, the weight of the propylene-α-olefin random copolymer (B) relative to the weight of the propylene-α-olefin random copolymer (A) can be adjusted by controlling the polymerization time or by controlling the catalyst such as carbon monoxide or hydrogen sulfide. Propylene-α-olefin random copolymer
The weight of (B) is adjusted to 1.0 to 50% by weight. further,
The molecular weight of the propylene-α-olefin random copolymer (B) is propylene-α-olefin random copolymer.
The intrinsic viscosity of the _{(B) ([η] B} ) is adjusted in addition to the time of polymerization of the molecular weight modifier propylene -α- olefin random copolymer such as hydrogen to meet the requirements of the propylene-based polymer blend (B) Is done.

As the polymerization system, any of a batch system, a non-continuous system, and a continuous system can be employed, but a continuous polymerization is industrially preferable.

After the completion of the second polymerization step, the monomer can be removed from the polymerization system to obtain a particulate polymer. The obtained polymer is subjected to measurement of intrinsic viscosity ([η] _WHOLE ), α-olefin content, and measurement of polymerization yield per unit weight of catalyst.

The propylene-based polymer blend of the present invention can be used as a raw material for molded articles having various shapes by various molding methods such as injection molding and extrusion molding. In molding, the propylene-based polymer blend may be used, if necessary, with known antioxidants, neutralizing agents, antistatic agents, weathering agents, inorganic materials such as talc, calcium carbonate, silica, and mica used in conventional polyolefins. Various additives such as a filler can be added.

[0040]

The present invention will be described more specifically with reference to examples and comparative examples. 1) Various physical property measuring methods The measuring methods adopted in the examples and comparative examples are as follows. a) Intrinsic viscosity (dl / g): Measured using an automatic viscosity measuring device (AVS2, manufactured by Mitsui Toatsu) under a temperature condition of 135 ° C. using tetralin (tetrahydronaphthalene) as a solvent. b) Particle size (μm) and uniformity of the titanium-containing solid catalyst component: The average particle size calculated from the particle size distribution measured using a master sizer (manufactured by MALVERN) is defined as the particle size, and 60%
The value obtained by dividing the particle size under the sieve by the particle size under the 10% sieve was defined as the uniformity. c) Ethylene unit content (% by weight): measured by an infrared absorption spectrum method. d) Melt flow rate (g / 10 minutes): JIS K-721
0 was measured.

2) Preparation of Titanium-Containing Solid Catalyst Component a) Titanium-containing solid catalyst component: A-1 A nitrogen-substituted SUS autoclave was charged with 95.3 g of anhydrous MgCl ₂ and 352 ml of dry EtOH.
This mixture was heated to 105 ° C. with stirring to dissolve. 1
After stirring for an hour, the solution was fed into a two-fluid spray nozzle with pressurized nitrogen (1.1 MPa) heated to 105 ° C. The flow rate of the nitrogen gas was 38 l / min. Liquid nitrogen for cooling was introduced into the spray tower, and the temperature in the tower was maintained at -15 ° C. The product was collected in cold hexane introduced into the bottom of the column to obtain 256 g. Analysis of the product indicated that the composition of this support was the same as MgCl ₂ .6EtOH as the starting solution. For use as a carrier, sieved to 45 to 212 µ
205 g of a spherical carrier having a particle size of m were obtained. The obtained carrier was dried by aeration at room temperature for 181 hours using nitrogen at a flow rate of 3 L / min to obtain a dried carrier having a composition of MgCl ₂ .1.7EtOH.

In a glass flask, dry carrier 20
g, 160 ml of titanium tetrachloride and 240 ml of purified 1,2-dichloroethane, and heated to 100 ° C. with stirring.
6.8 ml of diisobutyl phthalate was added, and further at 100 ° C.
For 2 hours. The liquid phase was removed by decantation, and 160 ml of titanium tetrachloride and 320 ml of purified 1,2-dichloroethane were added again. After heating and maintaining at 100 ° C. for 1 hour, the liquid phase was removed by decantation, washed with purified hexane, and dried to obtain a titanium-containing solid catalyst component: A-1. The obtained titanium-containing solid catalyst component:
The average particle size of A-1 is 115 μm, and the analysis value is
Mg: 19.5% by weight, Ti: 1.6% by weight, Cl: 5
9.0% by weight, diisobutyl phthalate; 4.5% by weight.

B) Titanium-containing solid catalyst component: A-2 Purified kerosene 105 was placed in a nitrogen-substituted SUS autoclave.
0 ml, anhydrous MgCl ₂ 15 g, dry ethanol 36.3 g
And 4.5 g of a surfactant (trade name: Emazol 320, manufactured by Kao Atlas Co., Ltd.), and the mixture was mixed with 800 r.
The temperature was raised while stirring at pm and maintained at 120 ° C. for 30 minutes. While stirring the molten mixture at a high speed, the mixture was transferred to a 3 liter stirring flask filled with 1.5 liter of purified kerosene cooled to -10 ° C using a Teflon tube having an inner diameter of 5 mm. After filtration, the product was sufficiently washed with hexane to obtain a carrier.

15 g of the carrier was added at room temperature to titanium tetrachloride 300
After suspending the mixture in 2.6 ml, 2.6 ml of diisobutyl phthalate were added and the mixture was heated to 120 ° C. 120
After stirring and mixing at a temperature of 2 ° C. for 2 hours, the solid was filtered and suspended again in 300 ml of titanium tetrachloride. 1 suspension solution
After stirring and mixing at 30 ° C. for 2 hours, the solid substance was filtered and sufficiently washed with purified hexane to obtain a titanium-containing solid catalyst component:
A-2 was obtained. The obtained titanium-containing solid catalyst component: A-
2 has an average particle size of 72 μm, and its analysis value is Mg;
21.1% by weight, Ti: 2.4% by weight, Cl: 64.5% by weight, diisobutyl phthalate: 5.3% by weight.

C) Titanium-containing solid catalyst component: A-3 A mixture of 300 g of magnesium ethoxyside, 550 ml of 2-ethylhexyl alcohol and 600 ml of toluene was stirred at 93 ° C. for 3 hours in a carbon dioxide atmosphere of 0.20 MPa, and then toluene was further added. 800 ml and 800 ml of n-decane were added to obtain a magnesium carbonate solution. 800 ml of toluene, 60 ml of chlorobenzene, 18 ml of tetraethoxysilane, 17 ml of titanium tetrachloride and Isopearl G
(Isoparaffinic hydrocarbon having an average of 10 carbon atoms, boiling point 156
(〜176 ° C.) While stirring 200 ml of the mixed solution at 30 ° C. for 5 minutes, 100 ml of the magnesium carbonate solution prepared above was added.

After further stirring for 5 minutes, 44 ml of tetrahydrofuran was added and the mixture was stirred at 60 ° C. for 1 hour. After the stirring was stopped and the supernatant was removed, the resulting solid was dissolved in toluene 10
After washing with 0 ml, the obtained solid was treated with 200 ml of chlorobenzene.
And 200 ml of titanium tetrachloride were added, and the mixture was stirred at 135 ° C. for 1 hour. After stirring was stopped and the supernatant was removed, 500 ml of chlorobenzene, 200 ml of titanium tetrachloride and 4.2 ml of di-n-butyl phthalate were added, and the mixture was stirred at 135 ° C for 1.5 hours. After removing the supernatant, the solid was washed sequentially with 1200 ml of toluene, 1600 ml of Isopearl G and 800 ml of hexane to obtain a titanium-containing solid catalyst component for comparison: A-3. The average particle size of the obtained titanium-containing solid catalyst component: A-3 was 16.2 μm, and its analysis value was Mg;
2.3% by weight, Ti: 55.0% by weight, di-n-butyl phthalate; 7.5% by weight.

3) Pre-Activation Treatment of Titanium-Containing Solid Catalyst Component After replacing a stainless steel reactor having an inner volume of 15 liters with inclined blades with nitrogen gas, a saturated solution having a kinematic viscosity at 40 ° C. of 7.3 centistokes was obtained. Hydrocarbon solvents (CRYSTOL-52,
8.3 liters, 525 mmol of triethylaluminum, diisopropyldimethoxysilane 8
0 mmol, the titanium-containing solid catalyst component 700 prepared in the preceding section
After adding g at room temperature, the mixture was heated to 40 ° C. and reacted at a propylene partial pressure of 0.15 MPa for 7 hours to perform a preactivation treatment. As a result of the analysis, 3.0 g of propylene was reacted per 1 g of the titanium-containing solid catalyst component.

4) First Polymerization Step In the flow sheet shown in the attached FIG. 1, the pre-activated titanium-containing solid catalyst component described above was placed in a horizontal polymerization vessel (L / D = 6, internal volume 100 liters) having stirring blades. 0.5g
/ Hr, triethylaluminum as an organoaluminum compound and diisopropyldimethoxysilane as an organosilicon compound were continuously supplied so as to have an Al / Si molar ratio shown in Tables 1 to 3. C2 / shown in Tables 1 to 3
A propylene-ethylene mixed gas having a C3 molar ratio is reacted at a reaction temperature of 65 ° C, a reaction pressure of 2.2 MPa, and a stirring speed of 40 rpm
And the hydrogen gas is continuously supplied from the circulation pipe 2 so as to maintain the hydrogen concentration in the gas phase of the reactor at the H2 / C3 molar ratio shown in Tables 1 to 3. The molecular weight was controlled by controlling the intrinsic viscosity of the resulting polymer, ie, the propylene-α-olefin random copolymer (A).

The reaction heat was removed by the heat of vaporization of the raw material propylene supplied from the pipe 3. The unreacted gas discharged from the polymerization reactor was cooled and condensed outside the reactor system through the pipe 4 and returned to the polymerization reactor 1. The propylene-α-olefin random copolymer (A) obtained in the present polymerization vessel is continuously withdrawn from the polymerization vessel 1 through the pipe 5 so that the level of the retained polymer becomes 50% by volume of the reaction volume. It was supplied to the polymerization vessel 10 in the polymerization step. At this time, propylene-
A part of the α-olefin random copolymer (A) was intermittently extracted, and used as a sample for obtaining ethylene content, intrinsic viscosity and polymer yield per unit weight of catalyst. The polymer yield per unit weight of the catalyst was measured by inductively coupled plasma emission spectroscopy (ICP method) of the Mg content in the polymer.

5) Second Polymerization Step Horizontal polymerization vessel 10 having stirring blades (L / D = 6, internal volume 10
(0 liter), the propylene-α-olefin random copolymer (A) and the ethylene-propylene mixed gas from the first polymerization step were continuously supplied to copolymerize ethylene and propylene. The reaction conditions were a stirring speed of 40 rpm, a temperature of 60 ° C., and a pressure of 2.2 MPa. The molar ratio was adjusted. Carbon monoxide as a polymerization activity inhibitor for adjusting the polymerization amount of the propylene-α-olefin random copolymer (B), and the propylene-α-olefin random copolymer (B)
Hydrogen gas for adjusting the molecular weight of was supplied from a pipe 7.

The reaction heat was removed by the heat of vaporization of the raw material liquid propylene supplied from the pipe 6. The unreacted gas discharged from the polymerization vessel was cooled and condensed outside the reactor system through the pipe 8 and returned to the copolymerization step. The propylene-based polymer blend produced in the copolymerization step is connected to the polymerization reactor 1 via the pipe 9 such that the level of the polymer held is 50% by volume of the reaction volume.
Extracted from zero. The production rate of the propylene-based polymer blend was 8 to 12 kg / hr.

The extracted propylene-based polymer blend removes the monomer, partially measures the intrinsic viscosity ([η] _WHOLE ), and measures the ethylene in the propylene-α-olefin random copolymer (B) by infrared _rays. Measurement and IC
It was used for the measurement of the polymerization ratio of the copolymer component by the measurement of the Mg content in the polymer by the P method. Further, the compressibility of the powder of the propylene-based polymer blend was calculated from the following equation, and the fluidity was evaluated. Compressibility = (solid apparent density-loose apparent density) x 100 /
The lower the value of the compact apparent density compression degree, the better the fluidity of the powder.

Kinds of titanium-containing solid catalyst components, Al / Si molar ratio, ethylene / propylene molar ratio and hydrogen / propylene molar ratio in the first polymerization step, and ethylene / propylene molar ratio and hydrogen / ethylene molar ratio in the second polymerization step Was changed as shown in Tables 1 to 3, and samples of Examples 1 to 6 and Comparative Examples 1 to 8 were obtained. Tables 1 to 3 show the measurement results of various physical properties.

6) Production of injection-molded article 0.004 kg of phenolic heat stabilizer and 0.004 kg of calcium stearate were added to 4 kg of the powder obtained above, and the mixture was stirred at room temperature using a high-speed stirring mixer (Henschel mixer). After mixing for 10 minutes, the mixture was granulated using an extrusion granulator having a screw diameter of 40 mm. Next, JI
An S-shaped test piece was prepared using an injection molding machine at a molten resin temperature of 230 ° C and a mold temperature of 50 ° C. The obtained test pieces were conditioned for 72 hours in a room at a humidity of 50% and a room temperature of 23 ° C., and various physical property values were measured based on the following methods. The results are shown in Tables 1 to 3.

A) Flexural modulus (MPa): JIS K 720
3 was measured. b) Haze: Measured in accordance with ASTM D 1003 using a 25 × 50 × 1 mm plate sample adjusted under the above conditions. c) Izod impact value: Measured according to JIS K 6758. d) Impact whitening: A 50 × 50 × 2 mm flat plate sample adjusted under the above conditions was subjected to a load drop under the following conditions using a DuPont impact tester (manufactured by Toyo Seiki), and the whitening point generated on the flat plate by the impact was measured. Was measured for diameter. Hammer tip radius 0.635cmR Cradle inner diameter 3.81cmφ Load 500g Load drop height 1m

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

The molded product obtained from the propylene-based polymer blend satisfying the above physical properties of the present invention is excellent in transparency, whitening resistance, impact resistance at low temperature, and balance among them. In addition, the method for producing a propylene-based polymer blend of the present invention has extremely high productivity because it is a continuous process.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a continuous polymerization apparatus used in Examples.

[Explanation of symbols]

 1 and 10: Polymerizer 2: Hydrogen pipe 3: Raw material propylene pipe 4 and 8: Unreacted gas pipe 5 and 9: Polymer extraction pipe 6: Raw material mixed gas pipe

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-31846 (JP, A) JP-A-61-287917 (JP, A) JP-A-6-93061 (JP, A) JP-A-6-93061 93062 (JP, A) JP-A-6-116391 (JP, A) JP-A-9-324022 (JP, A) JP-A-10-87744 (JP, A) JP-A-10-212361 (JP, A) JP-A-6-87991 (JP, A) JP-A-2-258854 (JP, A) JP-A-58-83016 (JP, A) JP-A-6-25367 (JP, A) (58) (Int.Cl. ⁷ , DB name) C08L 23/16 C08F 2/34 C08F 4/642 C08F 210/06 WPI (DIALOG)

Claims (3)

(57) [Claims] A propylene-α-olefin random copolymer (A) containing 90 to 98.5% by weight of propylene and 90 to 50% by weight of propylene and 55 to 8% by weight of propylene.
A propylene-based polymer blend containing 10 to 50% by weight of a propylene-α-olefin random copolymer (B) contained in a range of 3% by weight, and a limit of the propylene-α-olefin random copolymer (B). Viscosity [η] _B is 1.3 to 3.5 dl / g, propylene-α-
The intrinsic viscosity ratio [η] _B / [η] _{A of the} olefin copolymer (B) and the propylene-α-olefin copolymer (A) is 0.5 to 1.5.
3, and the intrinsic viscosity ratio of the propylene-α-olefin copolymer (A) and the propylene-α-olefin copolymer (B)
The product of [η] _B / [η] _A and their weight ratio W _A / W _B ([η] _B
/ [Η] _A ) · (W _A / W _B ) is in the range of 1.0 to 4.5. 2. In the presence of a stereoregular catalyst comprising a combination of a titanium-containing solid catalyst component having an average particle diameter of 20 to 300 μm, an organoaluminum compound and an organosilicon compound, propylene and α-
90-50% by weight of the total weight by copolymerizing with olefin
A first polymerization step of producing a propylene-α-olefin random copolymer (A), and then copolymerizing propylene and an α-olefin other than propylene at a different composition ratio from the first polymerization step, and A second polymerization step of producing 10 to 50% by weight of a propylene-α-olefin random copolymer (B), wherein the propylene-based polymer blend is obtained by continuously performing propylene in an amount of 90 to 98%. 0.5 to 90% by weight based on the weight of the propylene-based polymer blend.
Propylene-α-olefin random copolymer (A) occupying 55% to 83% by weight of the propylene-based polymer blend and 10 to 50% by weight of the propylene-based polymer blend. α-olefin random copolymer (B), wherein the propylene-α-olefin random copolymer (B) has an intrinsic viscosity [η] _B of 1.3 to 3.5 dl / g, and propylene-α-
The intrinsic viscosity ratio [η] _B / [η] _{A of the} olefin copolymer (B) and the propylene-α-olefin copolymer (A) is 0.5 to 1.5.
3, and the intrinsic viscosity ratio of the propylene-α-olefin copolymer (A) and the propylene-α-olefin copolymer (B)
The product of [η] _B / [η] _A and their weight ratio W _A / W _B ([η] _B
/ [Η] _A ) · (W _A / W _B ) is in the range of 1.0 to 4.5. 3. The propylene-based polymer blend according to claim 2, wherein the organoaluminum compound / organosilicon compound (Al / Si) molar ratio is 1.5 to 8.