JP7480871B2 - Branched polypropylene polymer - Google Patents

Description

The present invention relates to a branched polypropylene polymer.

Polypropylene is characterized by its low density and excellent chemical resistance, and is also highly recyclable. It does not emit toxic gases when incinerated, making it an excellent material for industrial use.
In recent years, much research has been conducted into introducing branched structures into polypropylene to improve its suitability for sheet molding, blow molding, thermoforming, foam molding, melt spinning, and other processes that require a material with a relatively high melt tension. In addition, progress is being made with its application to injection molding, injection foam molding, and its modification and fiber fields.

Recently, a macromer copolymerization method that mainly uses a metallocene catalyst has been proposed. Branched polypropylene produced by the macromer copolymerization method has the advantage that it produces less gel due to crosslinking reactions compared to polypropylene in which a branched structure has been introduced by irradiating with an electron beam, etc.

As such a macromer copolymerization method, for example, a method has been proposed in which a propylene macromer having a vinyl structure at the end is produced using a specific catalyst and specific polymerization conditions in the first polymerization stage (macromer synthesis process), and then propylene and the propylene macromer are copolymerized using a specific catalyst and specific polymerization conditions in the second polymerization stage (macromer copolymerization process). It has been shown that the resulting branched polypropylene has high melt strength and melt tension (see, for example, Patent Documents 1 and 2).

Also, a single-stage polymerization method has been proposed in which a macromer synthesis step and a macromer copolymerization step are carried out simultaneously using a specific metallocene catalyst, and it has been shown that the resulting branched polypropylene exhibits improved melt strength (see, for example, Patent Document 3).
Furthermore, a method for _multi -stage polymerization has been proposed using a catalyst that combines a catalyst containing two specific metallocene compounds, specifically, metallocene compounds such as rac- _SiMe2 [2-Me-4-Ph-lnd] _2ZrCl2 and rac- _SiMe2 [ ₂ -Me-4-Ph-lnd] _2HfCl2 , with silica carrying methylaluminoxane (MAO), and it has been reported that the resulting propylene-based polymer exhibits a relatively high melt tension (see Patent Document 4).

Also, a method has been devised in which a catalyst containing a specific metallocene compound and an ion-exchangeable layered silicate is used, and it has been reported that the resulting propylene-based polymer has a broad molecular weight distribution, a large amount of branching, and good melt tension (see Patent Document 5).
Furthermore, a method has been devised in which a catalyst containing a specific number of metallocene compounds is used, and it has been reported that the resulting propylene-based polymer has good melt tension (see Patent Document 6).

However, all of the propylene-based polymers disclosed in Patent Documents 1 to 6 have problems with extensional viscosity, with room for improvement, and poor melt fluidity.

JP 2001-525460 A Japanese Patent Application Laid-Open No. 10-338717 JP 2002-523575 A JP 2001-64314 A JP 2007-154121 A JP 2009-57542 A

As described above, the propylene-based polymers having a branched structure obtained by the macromer copolymerization methods proposed and devised so far have a problem of poor balance between melt fluidity and extensional viscosity.
Here, the extensional viscosity is considered to be a property that can affect the uniformity of wall thickness in sheet molding, blow molding, etc., the uniformity of foam cell diameter in foam molding, etc., and the fineness of fiber diameter in melt spinning, etc.
A propylene-based polymer degraded by peroxide can be a material having good melt fluidity. However, as shown in the comparative example described later, improving the melt fluidity leads to a decrease in the extensional viscosity, and the balance between the melt fluidity and the extensional viscosity is not necessarily good.
Therefore, an object of the present invention is to provide a propylene polymer having an excellent balance between melt fluidity and extensional viscosity.

As a result of intensive research, the present inventors have discovered that a branched polypropylene polymer has an excellent balance between melt fluidity and elongational viscosity by having a branched polypropylene structure, particularly a molecular weight distribution and branching distribution, that is different from conventional branched polypropylene polymers.

The branched polypropylene polymer of the present invention has the following properties (1) to (5).
Property (1): The melt flow rate (MFR) measured at a temperature of 230° C. under a load of 2.16 kg is greater than 100 g/10 min and is 1,000 g/10 min or less.
Property (2): The weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) is 50,000 or more and 160,000 or less, and the ratio (Q value) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.0 or more and 4.5 or less.
Property (3): In a molecular weight distribution curve obtained by GPC, when the common logarithm of the molecular weight corresponding to the peak position is Tp, the common logarithms of the molecular weight at a position corresponding to 20% of the peak height are L ₂₀ and H ₂₀ (L ₂₀ is on the lower molecular weight side than Tp, and H ₂₀ is on the higher molecular weight side than Tp), and wL=Tp-L ₂₀ and wH=H ₂₀ -Tp, wL/wH is 1.15 or more and 1.50 or less.
Property (4): In an integrated molecular weight distribution curve obtained by GPC, the proportion of components having a molecular weight of 1,000,000 or more (W _1M ) is 0.1% by weight or more and less than 2.5% by weight.
Property (5): In the molecular weight distribution curve obtained by 3D-GPC,
There is a relationship of M _abs pt < Mw _abs < Mz _abs < 1 million,
The branching index g' (M _abs pt) at M _abs pt is 0.90 or more and 1.00 or less; the branching index g' (Mw _abs ) at Mw _abs is 0.88 or more and less than 1.00; the branching index g' (Mz _abs ) at Mz _abs is 0.75 or more and less than 0.88; and the branching index g' (1M) at an absolute molecular weight M _abs of 1 million is 0.70 or more and 0.81 or less.
Here, M _abs pt, Mw _abs and Mz _abs respectively represent the absolute molecular weight, the weight average molecular weight and the z-average molecular weight corresponding to the peak position.

The branched polypropylene polymer of the present invention preferably further has the following property (6) from the viewpoint of the balance between melt fluidity and elongational viscosity in a shear or elongational deformation field.
Property (6): The branched polypropylene-based polymer has a side chain and a main chain,
the mesopentad fraction (mmmm) of the side chains measured by ^13C -NMR is in the range of 96% or more and less than 98%, the amount of hetero bonds (2,1 bonds) is in the range of 0 mol% or more and less than 0.30 mol%, and the amount of hetero bonds (1,3 bonds) is in the range of 0.05 mol% or more and less than 0.20 mol%,
The main chain has a mesopentad fraction (mmmm) measured by ¹³ C-NMR of 98% or more and less than 99%, a heterogeneous bond amount (2,1 bond) of 0.30 mol % or more and 1.00 mol % or less, and a heterogeneous bond amount (1,3 bond) of 0.20 mol % or more and 0.50 mol % or less.

It is preferable that the branched polypropylene polymer of the present invention further has the following property (7) from the viewpoint of improving heat resistance, rigidity, and tactile sensation such as touch.
Property (7): In an elution curve obtained by temperature rising elution fractionation (TREF) measurement using o-dichlorobenzene (ODCB), the content of components eluted at a temperature of 40° C. or less is 0.1% by weight or more and 3.0% by weight or less.

It is preferable that the branched polypropylene polymer of the present invention further has the following property (8) from the viewpoint of heat resistance of the product.
Property (8): The melting point (Tm) measured by differential scanning calorimetry (DSC) is 145° C. or higher and 157° C. or lower.

It is preferable that the branched polypropylene polymer of the present invention further has the following property (9) from the viewpoints of heat resistance, rigidity and transparency of the product.
Property (9): The crystallization temperature (Tc) measured by differential scanning calorimetry (DSC) is 113° C. or higher and 118° C. or lower, and the melting point (Tm) and crystallization temperature (Tc) measured by differential scanning calorimetry (DSC) satisfy the following formula (2).
37<Tm-Tc≦0.907×Tm-99.64 (2)

The present invention provides a propylene-based polymer that has an excellent balance between melt fluidity and elongational viscosity.

FIG. 1 is a diagram showing an example of a molecular weight distribution curve and an integrated molecular weight distribution curve. FIG. 2 is a diagram for explaining the baseline and intervals of a chromatogram in GPC. FIG. 3 is a graph showing the relationship between the extensional viscosity (unit: kPa·s) and the MFR (unit: g/10 min) at an extension rate of 300/s for the propylene-based polymers of the examples and comparative examples.

The branched polypropylene polymer of the present invention has the following properties (1) to (5).
Property (1): The melt flow rate (MFR) measured at a temperature of 230° C. under a load of 2.16 kg is greater than 100 g/10 min and is 1,000 g/10 min or less.
Property (2): The weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) is 50,000 or more and 160,000 or less, and the ratio (Q value) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.0 or more and 4.5 or less.
Property (3): In a molecular weight distribution curve obtained by GPC, when the common logarithm of the molecular weight corresponding to the peak position is Tp, the common logarithms of the molecular weight at a position corresponding to 20% of the peak height are L ₂₀ and H ₂₀ (L ₂₀ is on the lower molecular weight side than Tp, and H ₂₀ is on the higher molecular weight side than Tp ₎ , _and wL/wH is 1.15 or more and 1.50 or less.
Property (4): In an integrated molecular weight distribution curve obtained by GPC, the proportion of components having a molecular weight of 1,000,000 or more (W _1M ) is 0.1% by weight or more and less than 2.5% by weight.
Property (5): In the molecular weight distribution curve obtained by 3D-GPC,
There is a relationship of M _abs pt < Mw _abs < Mz _abs < 1 million,
The branching index g' (M _abs pt) at M _abs pt is 0.90 or more and 1.00 or less; the branching index g' (Mw _abs ) at Mw _abs is 0.88 or more and less than 1.00; the branching index g' (Mz _abs ) at Mz _abs is 0.75 or more and less than 0.88; and the branching index g' (1M) at an absolute molecular weight M _abs of 1 million is 0.70 or more and 0.81 or less.
Here, M _abs pt, Mw _abs and Mz _abs respectively represent the absolute molecular weight, the weight average molecular weight and the z-average molecular weight corresponding to the peak position.
The branched polypropylene-based polymer of the present invention has the above-mentioned properties (1) to (5), and is a propylene-based polymer excellent in balance between melt fluidity and elongational viscosity due to the fact that it has a branched polypropylene structure, particularly a molecular weight distribution and a branching distribution, different from conventional ones.
The branched polypropylene-based polymer of the present invention has a specific molecular weight distribution in which the Q value, which is an index showing the spread of the molecular weight distribution, is in a specific range, and wL/wH, which is an index showing the bias of the spread of the molecular weight distribution toward the low molecular weight side, is in a specific range, and the molecular weight distribution is biased toward the low molecular weight side while containing an appropriate amount of high molecular weight components, and the z-average molecular weight is less than 1 million. In this specific molecular weight distribution, the branching index at the absolute molecular weight corresponding to the peak top of the molecular weight distribution and the branching index at the weight average molecular weight are close to 1.00, indicating few branches, and the branching index at the z-average molecular weight and the branching index at a molecular weight of 1 million are within a specific range, indicating a branching distribution in which the branching increases within the specific range as the molecular weight increases. By having a specific branching distribution in this specific molecular weight distribution, the branched polypropylene-based polymer of the present invention has good fluidity while increasing the elongational viscosity commensurate with the fluidity, and as a whole, the balance between the elongational viscosity and the melt fluidity is good.

The physical properties and production method of the branched polypropylene polymer of the present invention will be described in detail below. In addition, in this specification, the numerical range "to" is used to mean that the numerical range includes the numerical ranges before and after it as the lower and upper limits.

I. Physical properties of branched polypropylene polymers (1):
The branched polypropylene polymer of the present invention has a melt flow rate (MFR) measured at a temperature of 230° C. under a load of 2.16 kg of more than 100 g/10 min and not more than 1,000 g/10 min.
MFR is an index of melt fluidity, and the value decreases as the molecular weight of a polymer increases, whereas the value increases as the molecular weight decreases.
If the MFR is too small, the melt fluidity becomes poor and thermoforming becomes difficult. Therefore, the MFR is greater than 100 g/10 min, preferably 200 g/10 min or more, and more preferably 300 g/10 min or more.
On the other hand, if the MFR is too high, it will cause a decrease in melt strength, and therefore the MFR is 1000 g/10 min or less, preferably 800 g/10 min or less, and more preferably 700 g/10 min or less.
In the present invention, the melt flow rate (MFR) is a value measured in accordance with JIS K7210 "Test method for melt mass flow rate (MFR) and melt volume flow rate (MVR) of plastics-thermoplastics" under test conditions of 230°C and a load of 2.16 kgf.
The melt flow rate (MFR) can be easily adjusted by changing the temperature or pressure of the polymerization or, as a general method, by adding a chain transfer agent such as hydrogen during the polymerization.

Characteristics (2):
The branched polypropylene polymer of the present invention has a weight average molecular weight (Mw) of 50,000 or more and 160,000 or less, as determined by gel permeation chromatography (GPC), and a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn; Q value) of 3.0 or more and 4.5 or less.
The branched polypropylene polymer of the present invention has an Mw of 50,000 or more and 160,000 or less from the viewpoint of the balance between melt fluidity and extensional viscosity. From the viewpoint of extensional viscosity, the Mw is preferably 80,000 or more, more preferably 90,000 or more, and from the viewpoint of melt fluidity, preferably 150,000 or less.
The Q value is an index showing the spread of the molecular weight distribution, and the larger this value, the wider the molecular weight distribution. If the Q value is too small, the amount of low molecular weight components decreases and the melt flowability becomes poor. Therefore, the Q value is 3.0 or more, preferably 3.2 or more, more preferably 3.4 or more, and even more preferably 3.6 or more.
On the other hand, if the Q value is too large, the amount of high molecular weight components increases relatively, and the melt fluidity deteriorates. Therefore, the Q value is 4.5 or less, preferably 4.3 or less, more preferably 4.0 or less, and even more preferably 3.8 or less.
The average molecular weight and molecular weight distribution (Mw, Mn, Q value) of the branched polypropylene polymer measured by GPC can be easily adjusted by changing the temperature and pressure conditions of propylene polymerization or, as the most common method, by adding a chain transfer agent such as hydrogen during propylene polymerization. Furthermore, they can be controlled by changing the type of metallocene complex used, or, when two or more types of complexes are used, the amount ratio thereof.

Characteristics (3):
In the branched polypropylene polymer of the present invention, when the common logarithm of the molecular weight corresponding to the peak position in a molecular weight distribution curve obtained by GPC is Tp, the common logarithms of the molecular weight at a position corresponding to 20% of the peak height are L ₂₀ and H ₂₀ (L ₂₀ is on the lower molecular weight side than Tp, and H ₂₀ is on the higher molecular weight side than Tp), and wL=Tp-L ₂₀ and wH=H ₂₀ -Tp, wL/wH, which is an index showing the bias of the spread of the molecular weight distribution toward the lower molecular weight side, is 1.15 or more and 1.50 or less.

The spread of the molecular weight distribution is shown by a molecular weight distribution curve obtained by GPC, which produces a graph with the common logarithm of the molecular weight (M) on the horizontal axis and the relative differential mass of the molecule corresponding to that molecular weight on the vertical axis.
The molecular weight referred to here is the molecular weight of each molecule constituting the branched polypropylene polymer, and is different from the weight average molecular weight (Mw) of the branched polypropylene polymer. Figure 1 is a diagram showing an example of a molecular weight distribution curve. wL and wH can be obtained from the graph created.
Usually, when homogeneous polymerization is carried out using a catalyst having a single active site, the molecular weight distribution will have the most probable distribution shape. The wL/wH of this most probable distribution is calculated to be 1.00.
This means that the molecular weight distribution of the branched polypropylene polymer of the present invention is biased toward the lower molecular weight side as compared with the molecular weight distribution of a polymer homogeneously polymerized using a catalyst having a single active site.
If wL/wH is too small, the amount of high molecular weight components becomes relatively large, and the melt fluidity decreases. If the melt fluidity decreases, hot molding becomes difficult. Therefore, wL/wH is 1.15 or more. In particular, from the viewpoint of fluidity in a high shear field or during high elongation deformation, wL/wH is preferably 1.16 or more.
On the other hand, if wL/wH is too large, the amount of high molecular weight components will be relatively small. If the amount of high molecular weight components is small, the amount of polymers with a large number of branches introduced per single chain will decrease, causing a decrease in melt strength and viscosity. Therefore, wL/wH is 1.50 or less. In particular, from the viewpoint of extensional viscosity, wL/wH is preferably 1.35 or less, and more preferably 1.34 or less.
In the molecular weight distribution curve, two or more peaks may appear. In that case, the peak with the maximum height can be regarded as the peak of the present invention. In addition, when two or more _H20s appear, the common logarithm of the molecular weight on the highest molecular weight side can be regarded as _H20 . Similarly, when two or more _L20s appear, the common logarithm of the molecular weight on the lowest molecular weight side can be regarded as _L20 .

In addition, in the branched polypropylene polymer of the present invention, it is preferable that wL/wH and the weight average molecular weight (Mw) satisfy the relationship represented by the following formula (1) in terms of a balance between fluidity and elongational viscosity in a high shear field or during high elongational deformation.
wL / wH>-0.17 × log(Mw) + 2.00 ... (1)

The bias of the molecular weight distribution toward the low molecular weight side can be easily adjusted by selecting one of the two or more metallocene complexes that can produce a high molecular weight polymer, and then controlling the amount of hydrogen added during polymerization. It can also be adjusted by changing the ratio of the two or more metallocene complexes used.

Property (4):
In the branched polypropylene polymer of the present invention, in an integrated molecular weight distribution curve obtained by GPC, the proportion (W _1M ) of components having a molecular weight of 1,000,000 or more is 0.1% by weight or more and less than 2.5% by weight, relative to 100% by weight of the total amount of the branched polypropylene polymer.
As mentioned above, a lower amount of high molecular weight component leads to a lower melt strength, therefore _W1M is 0.1 wt% or more, preferably 0.2 wt% or more, more preferably 0.3 wt% or more.
On the other hand, if _W1M is large, the melt fluidity is decreased. Furthermore, the number of fish eyes increases, which may cause a problem of impairing the appearance of the molded product. Therefore, _W1M is less than 2.5% by weight, preferably 2.0% by weight or less, more preferably 1.5% by weight or less, and even more preferably 1.0% by weight or less.
In the present invention, _W1M is defined as the value obtained by subtracting from 1 the integral value up to a molecular weight (M) of 1 million (Log(M)=6.0) in an integrated molecular weight distribution curve (total amount normalized to 1) obtained by GPC, and multiplying the result by 100. An example of an integrated molecular weight distribution curve is shown in FIG.
For example, in a method using a catalyst containing a plurality of metallocene complexes, _W1M can be easily adjusted by selecting one of the metallocene complexes capable of producing a high molecular weight polymer as one of the metallocene complexes to be used, and then controlling the amount of the selected metallocene complex relative to the other metallocene complex producing a low molecular weight polymer, the amount of hydrogen added during polymerization, and the polymerization temperature.

The number average molecular weight (Mn), weight average molecular weight (Mw), Q value, wL/wH and _W1M values defined above are all obtained by gel permeation chromatography (GPC), and the details of the measurement method and measurement equipment are as follows.
Apparatus: Waters GPC (ALC/GPC, 150C)
Detector: FOXBORO MIRAN, 1A, IR detector (measurement wavelength: 3.42 μm)
Column: Showa Denko AD806M/S (3 columns)
Mobile phase solvent: o-dichlorobenzene (ODCB)
Measurement temperature: 140°C
Flow rate: 1.0 mL/min Injection volume: 0.2 mL
The sample is prepared by preparing a 1 mg/mL solution using the sample and ODCB (containing 0.5 mg/mL dibutylhydroxytoluene (BHT)) and dissolving the sample at 140° C. for about 1 hour.
The baseline and interval of the obtained chromatogram are as shown in FIG.
The retention volume obtained by GPC measurement is converted into the molecular weight using a calibration curve prepared in advance using standard polystyrenes. The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
Brands: F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A 0.2 mL solution of each of the compounds dissolved in ODCB (containing 0.5 mg/mL BHT) was injected so that the concentration of each compound was 0.5 mg/mL, and a calibration curve was created using a cubic equation obtained by approximating the curve using the least squares method.
Viscosity equation used for conversion to molecular weight: [η] = K × M The following values are used for ^α .
PS: K = 1.38 × 10 ^-4 , α = 0.7
PP: K=1.03×10 ⁻⁴ , α=0.78

Property (5) Branching index g' measured by 3D-GPC
The branched polypropylene polymer of the present invention has the following molecular weight distribution curve obtained by 3D-GPC:
There is a relationship of M _abs pt < Mw _abs < Mz _abs < 1 million,
The branching index g' (M _abs pt) at M _abs pt is 0.90 or more and 1.00 or less; the branching index g' (Mw _abs ) at Mw _abs is 0.88 or more and less than 1.00; the branching index g' (Mz _abs ) at Mz _abs is 0.75 or more and less than 0.88; and the branching index g' (1M) at an absolute molecular weight M _abs of 1 million is 0.70 or more and 0.81 or less.
Here, M _abs pt, Mw _abs and Mz _abs respectively represent the absolute molecular weight, the weight average molecular weight and the z-average molecular weight corresponding to the peak position.
The branched polypropylene polymer of the present invention, when having a branching distribution within the above range, can maintain a balance between the overall melt strength, particularly the extensional viscosity and the melt fluidity.

The branched polypropylene polymer of the present invention has a relationship of M _abs pt < Mw _abs < Mz _abs < 1 million in a molecular weight distribution curve obtained by 3D-GPC. Here, the M _abs pt corresponding to the maximum component is considered to be easily correlated with fluidity under high stress. It is presumed that the melt fluidity is good when the M _abs pt corresponding to the maximum component is less than the Mw _abs . In addition, the Mz _abs is considered to be correlated with a high molecular weight component, and it is presumed that the melt fluidity is good when the Mz _abs is less than 1 million.

The branched polypropylene polymer of the present invention has a branching index g'(M _abs pt) at M _abs pt of 0.90 or more and 1.00 or less in a molecular weight distribution curve obtained by 3D-GPC. Since the branching index g'(M _abs pt) at the M _abs pt corresponding to the maximum component is 1.00 or close to 1.00, the maximum component indicates that the branched components are few. It is presumed that the melt fluidity is good in the maximum component due to the few branched components.
In particular, from the viewpoint of fluidity under high stress, the branched polypropylene polymer of the present invention preferably has a branching index g'(M _abs pt) at the above M _abs pt of 0.91 or more, more preferably 0.92 or more.

In the branched polypropylene polymer of the present invention, the branching index g' (Mw _abs ) at Mw _abs is 0.88 or more and less than 1.00 in a molecular weight distribution curve obtained by 3D-GPC. Since the branching index g' (Mw _abs ) at the weight average molecular weight Mw _abs is also close to 1.00, it indicates that the components in the weight average molecular weight also have few branched components. It is presumed that the melt fluidity is good because the components in the weight average molecular weight also have few branched components.
In order to obtain a good balance between melt fluidity and elongational viscosity, it is preferable that a component having a weight average molecular weight Mw _abs higher than the component having the maximum molecular weight M _abs pt has more branches, that is, the branching index g'(M _abs pt) is greater than the branching index g'(Mw _abs ).
In particular, from the viewpoint of fluidity under high stress, the branched polypropylene polymer of the present invention preferably has a branching index g'(Mw _abs ) at the Mw _abs of 0.89 or more,
It is more preferably 0.90 or more, while it is more preferably 0.98 or less, and further preferably 0.95 or less.

The branched polypropylene polymer of the present invention has a branching index g'(Mz _abs ) at Mz _abs of 0.75 or more and less than 0.88 in a molecular weight distribution curve obtained by 3D-GPC. It is presumed that the extensional viscosity is improved because the branching index g'(Mz _abs ) at Mz _abs , which correlates with the high molecular weight component, is less than 0.88 and there is a large amount of branching in the high molecular weight component. On the other hand, it is presumed that the balance with melt fluidity is also good because the branching index g'(Mz _abs ) is 0.75 or more and there is not too much branching in the high molecular weight component.
In particular, in terms of extensional viscosity, the branched polypropylene polymer of the present invention preferably has a branching index g'(Mz _abs ) in the Mz _abs of 0.76 or more,
It is more preferably 0.77 or more, while it is more preferably 0.87 or less, and further preferably 0.86 or less.

The branched polypropylene polymer of the present invention has a branching index g'(1M) of 0.70 or more and 0.81 or less at an absolute molecular weight M _abs of 1 million in a molecular weight distribution curve obtained by 3D-GPC. Since the branching index g'(1M) of the component in the highest molecular weight region is 0.81 or less and the component in the highest molecular weight region has many branches, it is presumed that a polymer having a large number of branches introduced per single chain effectively acts to improve the extensional viscosity. On the other hand, since the branching index g'(1M) is 0.70 or more and the branching is not too large, it is presumed that a good balance with melt fluidity is also achieved.
In particular, in terms of extensional viscosity, the branched polypropylene polymer of the present invention preferably has a branching index g'(1M) at an absolute molecular weight M _abs of 1 million of 0.71 or more, more preferably 0.72 or more, and on the other hand, preferably 0.80 or less, more preferably 0.79 or less.

The branching index g' is given by the ratio ([η] _br /[η] _lin ) of the intrinsic viscosity [η] _br of a polymer having a long chain branching structure to the intrinsic viscosity [η] _lin of a linear polymer having the same molecular weight, and when a long chain branching structure is present, the branching index g' has a value smaller than 1.0.
The definition is described, for example, in "Developments in Polymer Characterization-4" (J.V. Dawkins ed. Applied Science Publishers, 1983), and is a guide known to those skilled in the art.
The branching index g' can be obtained as a function of the absolute molecular weight M _abs , for example, by using 3D-GPC equipped with a light scattering meter and a viscometer as detectors as described below.
In this specification, 3D-GPC refers to a GPC apparatus connected with three detectors: a differential refractometer (RI), a viscometer, and a multi-angle laser light scattering detector (MALLS).
The GPC apparatus used is Alliance GPCV2000 manufactured by Waters Corporation, equipped with a differential refractometer (RI) and a viscometer. In addition, the light scattering detector used is a multi-angle laser light scattering detector (MALLS) manufactured by Wyatt Technology, DAWN-E.
The detectors are connected in the following order: MALLS, RI, and Viscometer.
The mobile phase solvent was 1,2,4-trichlorobenzene (containing the antioxidant Irganox 1076 manufactured by BASF Japan at a concentration of 0.5 mg/mL).
The flow rate is 1 mL/min, and two columns, GMHHR-H(S)HT manufactured by Tosoh Corporation, are connected in series.
The temperatures of the column, the sample injection part and each detector were 140°C.
The sample concentration was 1 mg/mL, and the injection volume (sample loop volume) was 0.2175 mL.
The absolute molecular weight (M _abs ), the root mean square radius of gyration (Rg) obtained from MALLS, and the intrinsic viscosity ([η]) obtained from Viscometer are calculated using the data processing software ASTRA (version 4.73.04) attached to MALLS, with reference to the following literature:
References:
1. Developments in Polymer Characterization, vol. 4. Essex: Applied Science; 1984. Chapter 1.
2. Polymer, 45, 6495-6505 (2004)
3. Macromolecules, 33, 2424-2436 (2000)
4. Macromolecules, 33, 6945-6952 (2000)
The branching index g′ is calculated as the ratio ([η] br /[η] _lin ) of the intrinsic _viscosity ([η] _br ) obtained by measuring a sample with the above-mentioned Viscometer to the intrinsic viscosity ([η] _lin ) obtained by separately measuring a linear polymer.

When a long chain branching structure is introduced into a polymer molecule, the radius of gyration becomes smaller compared to a linear polymer molecule of the same molecular weight. Since the intrinsic viscosity decreases as the radius of gyration becomes smaller, the ratio ([η] _br /[η] _lin ) of the intrinsic viscosity of the branched polymer ([η] _br ) to the intrinsic viscosity ([η] _lin ) of a linear polymer of the same molecular weight becomes smaller as the long chain branching structure is introduced. Therefore, a polymer having a long chain branching structure has a branching index g' ([η] _br /[η] _lin ) smaller than 1.0, and a linear polymer has a branching index g' of 1.0 by definition.
Here, [η] _lin is obtained using a commercially available homopolypropylene (Novatec PP (registered trademark) grade name: FY6 manufactured by Japan Polypropylene Corporation) as the linear polymer. The fact that the logarithm of [η] _lin of a linear polymer has a linear relationship with the logarithm of the molecular weight is known as the Mark-Houwink-Sakurada equation, so the value of [η] _lin can be obtained by appropriately extrapolating to the low molecular weight side or the high molecular weight side.
The branching index g' of less than 1.0 can be achieved by introducing a large amount of long chain branches, and this can be achieved by controlling the selection of catalysts, their combination and amount ratio, and the prepolymerization conditions.
Each branching index g' can be set within the above-mentioned specific range by appropriately adjusting the amount of hydrogen during polymerization in addition to the selection of catalysts, their combination and amount ratio, as described below.

The branched polypropylene polymer of the present invention preferably further has the following property (6) from the viewpoint of improving the balance between the melt fluidity and the extensional viscosity.
Characteristics (6):
The branched polypropylene polymer has a side chain and a main chain,
the mesopentad fraction (mmmm) of the side chains measured by ^13C -NMR is in the range of 96% or more and less than 98%, the amount of hetero bonds (2,1 bonds) is in the range of 0 mol% or more and less than 0.30 mol%, and the amount of hetero bonds (1,3 bonds) is in the range of 0.05 mol% or more and less than 0.20 mol%,
The main chain has a mesopentad fraction (mmmm) measured by ¹³ C-NMR of 98% or more and less than 99%, a heterogeneous bond amount (2,1 bond) of 0.30 mol % or more and 1.00 mol % or less, and a heterogeneous bond amount (1,3 bond) of 0.20 mol % or more and 0.50 mol % or less.

In the branched polypropylene polymer of the present invention, it is preferable that the mesopentad fraction (mmmm) of five consecutive propylene units in the side chains and main chain is within the above range from the viewpoint of improving the balance between melt fluidity and elongational viscosity.
Furthermore, the branched polypropylene polymer of the present invention may have the following 2,1 bond and 1,3 bond based on irregular insertion of propylene in addition to the structure based on regular 1,2 insertion of propylene inside the polymer. From the viewpoint of improving the balance between melt fluidity and elongational viscosity, it is preferable that the amount of heterogeneous bonds (2,1 bond) and the amount of heterogeneous bonds (1,3 bond) in the side chain and main chain are each within the above-mentioned range.

It is more preferable that the branched polypropylene polymer has, as a side chain, a polymer produced from a complex which produces a vinyl-terminated macromer, and has, as a main chain, a polymer produced from a complex which is different from the complex which copolymerizes the vinyl-terminated macromer, and each of them has the following regularity: An example of the complex which produces the vinyl-terminated macromer is the complex [A-1] described below, and an example of the complex which is different from the complex [A-1] which copolymerizes the vinyl-terminated macromer is the complex [A-2] described below.
The branched polypropylene polymer has a side chain and a main chain,
the mesopentad fraction (mmmm) of the side chain measured by ^13C -NMR is in the range of 96% or more and less than 98%, the amount of hetero bonds (2,1 bonds) is in the range of 0 mol% or more and 0.10 mol% or less, and the amount of hetero bonds (1,3 bonds) is in the range of 0.05 mol% or more and less than 0.15 mol%,
It is more preferable that the mesopentad fraction (mmmm) of the main chain measured by ^13C -NMR is 98% or more and less than 99%, the hetero-bond amount (2,1 bond) is 0.50 mol% or more and 1.00 mol% or less, and the hetero-bond amount (1,3 bond) is 0.30 mol% or more and 0.50 mol% or less.
The range is.

The crystallinity of polypropylene polymers is affected by stereoregularity and regioregularity. In particular, polypropylene polymers obtained by metallocene catalysts are different from polypropylene polymers obtained by ZN (Ziegler-Natta) catalysts in that they are affected by both stereoregularity indicated by mmmm and heterogeneous bonds due to defects in regioregularity indicated by the amount of heterogeneous bonds (2,1 bonds) and the amount of heterogeneous bonds (1,3 bonds). In other words, crystallization progresses as lamellae fold back from the defective parts of regularity (sterically irregular bonds and heterogeneous bonds).
It is believed that when the branched polypropylene polymer of the present invention has the number of branching points and the regularity of the components of the main chain and side chains having different molecular chain lengths within the above-mentioned ranges, the balance between the melt fluidity and the elongational viscosity is improved due to the crystallization process caused thereby in a shear or elongation deformation field.

It is extremely difficult to directly analyze the regularity of the main chain and the regularity of the side chain of a branched polypropylene-based polymer. However, in the case of using a catalyst component which polymerizes propylene to produce a propylene macromonomer and a catalyst component which copolymerizes propylene and the propylene macromonomer to produce a branched polypropylene, the regularity value of the polypropylene-based polymer when polymerized using the former catalyst component and the latter catalyst component alone, respectively, can be adopted.
In other words, the number and regularity of the main chain branches are determined by identifying the polypropylene homopolymer obtained by polymerization using the latter catalyst component, taking advantage of the fact that they are derived from the latter catalyst component. Furthermore, these components mainly appear on the lower molecular weight side of the peak top in the molecular weight distribution curve obtained by GPC.
The number and regularity of side chain branches are derived from the former catalyst component, and are determined by identifying the polypropylene homopolymer obtained by polymerization using the former catalyst component. These components mainly appear on the higher molecular weight side of the peak top in the molecular weight distribution curve obtained by GPC.

( ^13C -NMR measurement method)
[Sample preparation and measurement conditions]
200 mg of a sample was placed in an NMR sample tube with an inner diameter of 10 mm together with 2.4 mL of o-dichlorobenzene/deuterated bromide benzene (C ₆ D ₅ Br)=4/1 (volume ratio) and hexamethyldisiloxane as a chemical shift standard substance, and dissolved homogeneously in a 150° C. block heater.
The NMR measurement is carried out using a Bruker Biospin AV400 NMR apparatus equipped with a 10 mmφ cryoprobe.
The ¹³ C-NMR measurement conditions are a sample temperature of 120° C., a pulse angle of 90°, a pulse interval of 15 seconds, and an accumulation count of 1024, and the measurement is performed by a broadband decoupling method.
The chemical shifts are set to 1.98 ppm for the ¹³ C signal of hexamethyldisiloxane, and the chemical shifts of other ¹³ C signals are based on this.

[Calculation method]
<Mesopentad fraction (mmmm)>
The mesopentad fraction (mmmm) of five consecutive propylene units can be determined by substituting the integrated intensity of the ¹³ C signal measured by ¹³ C-NMR measurement into the following formula (3).
mmmm(%)=(I _mm -2×I _mrrm )×100
/(I _mm + 3 × I _mrrm ) ... formula (3)
Here, I _mm represents the integrated intensity of the ¹³ C signal assigned to a bonding mode in which three consecutive propylene units are mm, and is calculated as the integrated intensity of the ¹³ C signal in the chemical shift range of 23.6 to 21.1 ppm (hereinafter, referred to as "I _23.6-21.1 ").
I _mrrm represents the integrated intensity of the ¹³ C signal attributable to the bonding mode of mrrm in five successive propylene units, and is a value shown as I _{19.9 to 19.7} .
Spectral assignment can be made with reference to Polymer Journal, vol. 16, p. 717 (1984), Asakura Publishing, Macromolecules, vol. 8, p. 687 (1975), and Polymer, vol. 30, p. 1350 (1989).
The chemical shift range shifts slightly depending on the molecular weight of the polymer, but the regions are easily distinguishable.

<Amount of heterogeneous bonds (2,1 bonds, 1,3 bonds)>
The amount of heterogeneous bond (molar concentration) is calculated from the signal intensity of the ¹³ C-NMR spectrum according to the following formula.
Propylene 2,1(m) bond (mol%)
= I _{2,1 (m) - P} × 100 / (I _{1,2 - P} + I _{2,1 (m) - P} + I _{2,1 (r) - P} + I _{1,3 - P} )
Propylene 2,1(r) bond (mol%)
= I _2,1(r)-P × 100/(I _1,2-P + I _2,1(m)-P + I _2,1(r)-P + I _1,3-P )
Propylene 1,3 bond (mol%)
= I _1,3-P × 100 / (I _1,2-P + I _{2,1 (m)-P} + I _{2,1 (r)-P} + I _1,3-P )
Here, I _1,2-P , I _2,1(m)-P , I _2,1(r)-P , and I _1,3-P are calculated as follows:
I _1,2-P = I _{48.80 to 44.50
I2,1(m)-P} = ( _I35.94-35.72 )/2
_I2,1(r)-P = ( _I32.63-32.55 + _I34.70-34.61 + _I35.39-34.57 )/3
I _1,3-P = I _{37.49 to 37.21} / 2

It is preferable that the branched polypropylene polymer of the present invention further has the following property (7) from the viewpoint of improving heat resistance, rigidity, and tactile sensation such as touch.
Property (7):
In the branched polypropylene polymer, the content of a component eluted at a temperature of 40° C. or lower is 0.1% by weight or more and 3.0% by weight or less in an elution curve obtained by temperature rising elution fractionation (TREF) measurement using o-dichlorobenzene (ODCB).
The components that dissolve at 40° C. or less are low-crystalline components, and if the amount of these components is large, the crystallinity decreases, and there is a risk that the heat resistance and rigidity of the product may decrease. Therefore, this amount is preferably 3.0% by weight or less, more preferably 2.0% by weight or less, even more preferably 1.0% by weight or less, and particularly preferably 0.7% by weight or less.
On the other hand, if the amount of components eluted at 40° C. or less is small, for example, when the fiber is molded, the rigidity may become too high, resulting in poor feel to the touch, etc. Therefore, this amount is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, even more preferably 0.3% by weight or more, and particularly preferably 0.4% by weight or more.

The content of the branched polypropylene polymer soluble at 40°C or less in temperature rising elution fractionation (TREF) with o-dichlorobenzene (ODCB) can generally be kept low by using a metallocene complex. In addition to maintaining the purity of the catalyst at a certain level or higher, it is preferable not to set the catalyst production method or reaction conditions during polymerization to extremely high temperatures, and not to increase the ratio of organoaluminum to the metallocene catalyst too much.
Details of the method for measuring the eluted components by temperature rising elution fractionation (TREF) are as follows.
The sample is dissolved in ODCB at 140° C. to obtain a solution. This is introduced into a TREF column at 140° C., and then cooled to 100° C. at a temperature drop rate of 8° C./min, and then cooled to 40° C. at a temperature drop rate of 4° C./min, and held for 10 minutes. Then, ODCB, which is a solvent, is passed through the column at a flow rate of 1 mL/min to elute the components dissolved in ODCB at 40° C. in the TREF column for 10 minutes, and then the column is linearly heated to 140° C. at a temperature increase rate of 100° C./hour to obtain an elution curve.
Column size: 4.3 mmφ×150 mm
Column packing material: 100 μm surface deactivated glass beads Solvent: o-dichlorobenzene (ODCB)
Sample concentration: 5 mg/mL
Sample injection volume: 0.1 mL
Solvent flow rate: 1 mL/min. Detector: fixed wavelength infrared detector. FOXBORO MIRAN, 1A
Measurement wavelength: 3.42 μm

It is preferable that the branched polypropylene polymer of the present invention further has the following property (8) from the viewpoint of improving the heat resistance of the product.
Characteristics (8):
The branched polypropylene polymer has a melting point (Tm) of 145° C. or more and 157° C. or less, as measured by differential scanning calorimetry (DSC).
The higher the Tm of the branched polypropylene polymer, the more improved its heat resistance and rigidity. Therefore, the Tm is preferably 145° C. or higher, more preferably 147° C. or higher, and even more preferably 149° C. or higher.
On the other hand, if the branched polypropylene polymer has too high a Tm, the rigidity may become too high, resulting in poor feel, such as touch, etc. Therefore, the Tm is preferably 157° C. or less, more preferably 155° C. or less, and even more preferably 153° C. or less.
In the case of polypropylene, Tm can be controlled by controlling the crystal thickness, and the crystal thickness is proportional to the regularly inserted propylene chains. In other words, Tm decreases due to the insertion of ethylene units or regioregular defects. The branched polypropylene polymer of the present invention can have Tm controlled by selecting an optimal complex for regioregular defects as a polymerization catalyst, selecting a combination of multiple complexes, and further controlling the polymerization temperature, pressure conditions, and crystal thickness.

It is preferable that the branched polypropylene polymer of the present invention further has the following property (9) from the viewpoints of heat resistance, rigidity and transparency of the product.
Characteristics (9):
The branched polypropylene polymer has a crystallization temperature (Tc) measured by differential scanning calorimetry (DSC) of 113° C. or higher and 118° C. or lower, and the melting point (Tm) and crystallization temperature (Tc) measured by differential scanning calorimetry (DSC) satisfy the following formula (2):
37<Tm-Tc≦0.907×Tm-99.64 (2)
That is, in the branched polypropylene polymer of the present invention, it is preferable that the difference between Tm and Tc (degree of supercooling: Tm-Tc) measured by DSC is small in proportion to Tm.
A high Tc in relation to Tm means that the polymer crystallizes more easily, has a faster crystallization rate, and has smaller and denser crystals than a branched polypropylene polymer with the same Tm. When a branched polypropylene polymer that crystallizes easily is used, the transparency due to the crystal size and amount, and the heat resistance and rigidity due to the crystal amount are higher in relation to Tm. If the degree of supercooling is too high, the transparency, heat resistance, and rigidity may be worse in relation to Tm.
On the other hand, if the degree of supercooling is too small, the crystallization corresponding to the Tm will be too fast, making it impossible to control the size and amount of the crystals formed, and there is a possibility that the desired physical properties will not be obtained.
In view of the above, it is preferable that the branched polypropylene polymer of the present invention satisfies the above formula (2).
Tm is controlled by the amount of heterogeneous bonds (stereoregularity, regioregularity) and the isotactic sequence length. In general propylene polymers, there is a linear correlation between Tm and Tc.
On the other hand, the fact that Tc is high relative to Tm is due to the contribution of the primary structure other than the heterogeneous bond amount (stereoregularity, regioregularity) and isotactic sequence length. In particular, in the case of a branched structure, it is believed that the branching points promote crystallization, and the more branches there are, the smaller the degree of supercooling becomes. Therefore, in order to obtain the branched polypropylene-based polymer of the present invention, it is preferable to select a complex that optimizes the heterogeneous bond amount (stereoregularity, regioregularity), isotactic sequence length, and amount of branches, and further to control the degree of supercooling by adjusting the polymerization temperature and pressure.
In the present invention, Tm and Tc can be determined by using a Seiko Instruments Inc. DSC (DSC6200) to pack 5 mg of a sheet-like sample piece into an aluminum pan, heating it from room temperature to 200° C. at a heating rate of 100° C./min, holding it for 5 minutes, and then cooling it to 40° C. at a heating rate of 10° C./min, and determining the maximum crystallization peak temperature (° C.) when crystallized as the crystallization temperature (Tc), and then heating it to 200° C. at a heating rate of 10° C./min to determine the maximum melting peak temperature (° C.) as the melting point (Tm).
The sheet-like sample can be obtained by sandwiching the branched polypropylene polymer powder between press plates, preheating the powder at 190°C for 2 minutes, pressing the powder at 5 MPa for 2 minutes, and then cooling the powder at 0°C and 10 MPa for 2 minutes.

The branched polypropylene polymer of the present invention preferably further has the following property (10) from the viewpoint of excellent extensional viscosity commensurate with the fluidity.
Property (10):
The branched polypropylene polymer has an extensional viscosity (unit: kPa·s) at an extension rate of 300/s and an MFR (unit: g/10 min) measured in accordance with JIS K7199 that satisfy the relationship represented by the following formula (4).
log (extension viscosity at extension rate of 300/s)>-1.44 × log (MFR) + 3.30 ... (4)
More preferably, the relationship represented by the following formula (4') is satisfied.
log (extension viscosity at extension rate of 300/s)>-1.44 × log (MFR) + 3.35 ... (4')
Generally, when the fluidity is increased, the extensional viscosity decreases and becomes insufficient, so it is desired that the propylene-based polymer has both the necessary fluidity and excellent extensional viscosity. The above formula (4) and formula (4') show that the branched polypropylene-based polymer has a superior extensional viscosity commensurate with the fluidity compared to the conventional branched polypropylene-based polymer. That is, in order to distinguish the branched polypropylene-based polymer of the present invention from the conventional ones, the extensional viscosity at an extensional speed of 300/s is considered to be a function negatively correlated with the increase in fluidity (MFR), the parameters of the function are set, and it is shown that the extensional viscosity at an extensional speed of 300/s of the propylene-based polymer produced by the present invention is larger in proportion to the fluidity than the extensional viscosity at an extensional speed of 300/s defined by the function. Specifically, based on the data of the examples and comparative examples, values of extensional viscosity and fluidity (MFR) at an extension speed of 300/s that distinguish the examples from the comparative examples of the prior art were assumed, and the parameters of the relational equation that holds between the extensional viscosity and fluidity (MFR) at an extension speed of 300/s were determined by the least squares method.

In the present invention, the extensional viscosity can be measured based on the provisions of JIS K7199. Specifically, for example, a capillary rheometer (twin capillary rheometer RH2200, manufactured by Rosand) is used, 26 g of weighed sample pellets are placed in two barrels, the temperature is raised, and the sample pellets are melted while degassing the air in the sample, and the pellets are held at 180°C for 10 minutes and measured under the following conditions. Using analysis software Flowmaster (manufactured by Rosand), a graph of extensional viscosity and a graph of shear viscosity are obtained from the measured data by performing correction for pressure loss caused by the capillary die (Burgeley correction) and Rabinovich correction. The extensional viscosity at an extensional speed of 300/s is obtained.
Barrel diameter: 15mm
Barrel length: 250mm
Capillary die material: tungsten carbide Capillary die: diameter 1 mm, length 16 mm, inlet angle 180°
and diameter 1 mm, length 0 mm, inflow angle 180°
Measurement mode: Twin capillary mode

II. Method for Producing Branched Polypropylene Polymer The method for producing the branched polypropylene polymer of the present invention is not particularly limited as long as it is a method that can produce a branched polypropylene polymer that satisfies the above-mentioned physical properties that are the characteristics of the present invention. For example, a macromer copolymerization method using a metallocene catalyst is included, and preferably a method using a catalyst containing a plurality of metallocene compounds as described below that can produce a long-chain branched polypropylene polymer is included.
As a method for producing the branched polypropylene polymer of the present invention, a method for producing a branched polypropylene polymer using the following catalyst components (A), (B) and (C) as a propylene polymerization catalyst can be mentioned as a suitable method.
(A): Two or more transition metal compounds of Group 4 of the periodic table selected from at least one of component [A-1], which is a compound represented by the following general formula (a1), and at least one of [A-2], which is a compound represented by the following general formula (a2): Component [A-1]: Compound represented by general formula (a1) Component [A-2]: Compound represented by general formula (a2) (B): Compound that reacts with component (A) to form an ion pair or ion-exchangeable layered silicate (C): Organoaluminum compound

The catalyst components (A), (B) and (C) will be described in detail below.
1. Catalyst Component (A)
1-1. Component [A-1]: Compound represented by general formula (a1) As the component [A-1], a metallocene compound represented by the following general formula (a1) is preferably used from the viewpoint of producing a propylene-based polymer having a high terminal vinyl ratio.

[In general formula (a1), R ¹¹ and R ¹² each independently represent a heterocyclic group having 4 to 16 carbon atoms containing nitrogen, oxygen or sulfur. R ¹³ and R ¹⁴ each independently represent an aryl group having 6 to 30 carbon atoms which may contain halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus or a plurality of hetero elements selected therefrom, or a heterocyclic group having 6 to 16 carbon atoms containing nitrogen, oxygen or sulfur. Q ¹¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, or a silylene group or germylene group which may have a hydrocarbon group having 1 to 20 carbon atoms, M ¹¹ represents zirconium or hafnium, and X ¹¹ and Y ¹¹ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silyl group having a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, an amino group or an alkylamino group having 1 to 20 carbon atoms. ］

The nitrogen-, oxygen- or sulfur-containing heterocyclic group having 4 to 16 carbon atoms for R ¹¹ and R ¹² is preferably a 2-furyl group, a substituted 2-furyl group, a substituted 2-thienyl group or a substituted 2-furfuryl group, more preferably a substituted 2-furyl group.
By making R ¹¹ and R ¹² a group selected from heterocyclic groups containing nitrogen, oxygen, or sulfur and having 4 to 16 carbon atoms, the terminal vinyl ratio (Rv) can be increased. In particular, by introducing a substituent of an appropriate size onto the heterocyclic group, the relative positional relationship between the heterocycle and the coordination field on the transition metal and the growing polymer chain can be made appropriate, thereby making it possible to further increase the terminal vinyl ratio (Rv).
In addition, examples of the substituent of the substituted 2-furyl group, the substituted 2-thienyl group, and the substituted 2-furfuryl group include alkyl groups having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, and a propyl group, halogen atoms, such as a fluorine atom and a chlorine atom, alkoxy groups having 1 to 6 carbon atoms, such as a methoxy group and an ethoxy group, and trialkylsilyl groups. Among these, a methyl group and a trimethylsilyl group are preferred, and a methyl group is particularly preferred.
Furthermore, R ¹¹ and R ¹² are particularly preferably a 5-methyl-2-furyl group. It is also preferable that R ¹¹ and R ¹² are the same as each other.

The above R ¹³ and R ¹⁴ are each independently an aryl group having 6 to 30 carbon atoms which may contain halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a plurality of hetero elements selected therefrom, or a heterocyclic group having 6 to 16 carbon atoms which contains nitrogen, oxygen, or sulfur.
In particular, by making R ¹³ and R ¹⁴ bulkier, a propylene polymer having higher stereoregularity, fewer heterogeneous bonds, and a higher terminal vinyl ratio can be obtained.
Thus, R ¹³ and R ¹⁴ are preferably in the range of 6 to 16 carbon atoms and are each preferably an aryl group having one or more hydrocarbon groups having 1 to 6 carbon atoms, silyl groups having a hydrocarbon group having 1 to 6 carbon atoms, halogen-containing hydrocarbon groups having 1 to 6 carbon atoms, or aryl groups which may have a halogen atom as a substituent on the aryl ring skeleton, and specific examples of such R ¹³ and R ¹⁴ include a 4-t-butylphenyl group, a 2,3-dimethylphenyl group, a 3,5-di-t-butylphenyl group, a 4-chlorophenyl group, a 4-trimethylsilylphenyl group, a 1-naphthyl group, and a 2-naphthyl group.
Furthermore, R ¹³ and R ¹⁴ are more preferably in the range of 6 to 16 carbon atoms, and are each a phenyl group having one or more hydrocarbon groups having 1 to 6 carbon atoms, silyl groups having a hydrocarbon group having 1 to 6 carbon atoms, halogen-containing hydrocarbon groups having 1 to 6 carbon atoms, or halogen atoms as substituents. The position of substitution is preferably the 4-position on the phenyl group. Specific examples of such R ¹³ and R ¹⁴ include a 4-t-butylphenyl group, a 4-biphenylyl group, a 4-chlorophenyl group, and a 4-trimethylsilylphenyl group. Furthermore, it is preferable that R ¹³ and R ¹⁴ are the same as each other.

The above ^X11 and ^Y11 are auxiliary ligands, which react with component (B) to produce an active metallocene capable of olefin polymerization. Therefore, as long as this purpose is achieved, the type of ligand for ^X11 and ^Y11 is not limited, and each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silyl group having a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group, or an alkylamino group having 1 to 20 carbon atoms.

The above ^Q11 represents a divalent hydrocarbon group having 1 to 20 carbon atoms linking two five-membered rings, or a silylene group or germylene group which may have a hydrocarbon group having 1 to 20 carbon atoms. When two hydrocarbon groups are present on the above-mentioned silylene group or germylene group, they may be linked to each other to form a ring structure.
Specific examples of ^Q11 include alkylene groups such as methylene, methylmethylene, dimethylmethylene, and 1,2-ethylene; aryl alkylene groups such as diphenylmethylene; silylene groups; alkyl silylene groups such as methylsilylene, dimethylsilylene, diethylsilylene, di(n-propyl)silylene, di(i-propyl)silylene, and di(cyclohexyl)silylene, (alkyl)(aryl)silylene groups such as methyl(phenyl)silylene, aryl silylene groups such as diphenylsilylene, alkyl oligosilylene groups such as tetramethyldisilylene, germylene groups, alkylgermylene groups in which the silicon of the silylene group having the above divalent hydrocarbon group having 1 to 20 carbon atoms is replaced with germanium, (alkyl)(aryl)germylene groups, and arylgermylene groups. Among these, a silylene group having a hydrocarbon group of 1 to 20 carbon atoms or a germylene group having a hydrocarbon group of 1 to 20 carbon atoms is preferred, with an alkylsilylene group and an alkylgermylene group being particularly preferred.

Among the compounds represented by the above general formula (a1), preferred compounds are specifically exemplified below.
(1) dichloro[1,1'-dimethylsilylenebis{2-(2-furyl)-4-phenyl-indenyl}]hafnium,
(2) dichloro[1,1'-dimethylsilylenebis{2-(2-thienyl)-4-phenyl-indenyl}]hafnium,
(3) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(4) dichloro[1,1'-diphenylsilylenebis{2-(5-methyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(5) dichloro[1,1'-dimethylgermylenebis{2-(5-methyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(6) dichloro[1,1'-dimethylgermylenebis{2-(5-methyl-2-thienyl)-4-phenyl-indenyl}]hafnium,
(7) dichloro[1,1'-dimethylsilylenebis{2-(5-t-butyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(8) dichloro[1,1'-dimethylsilylenebis{2-(5-trimethylsilyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(9) dichloro[1,1'-dimethylsilylenebis{2-(5-phenyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(10) dichloro[1,1'-dimethylsilylenebis{2-(4,5-dimethyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(11) dichloro[1,1'-dimethylsilylenebis{2-(2-benzofuryl)-4-phenyl-indenyl}]hafnium,
(12) dichloro[1,1'-dimethylsilylenebis{2-(2-furfuryl)-4-phenyl-indenyl}]hafnium,
(13) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-chlorophenyl)-indenyl}]hafnium,
(14) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-fluorophenyl)-indenyl}]hafnium,
(15) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-trifluoromethylphenyl)-indenyl}]hafnium,
(16) dichloro[1,1′-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-isopropyl-phenyl)-indenyl}]hafnium,
(17) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-t-butylphenyl)-indenyl}]hafnium,
(18) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-trimethylsilylphenyl)-indenyl}]hafnium,
(19) dichloro[1,1'-dimethylsilylenebis{2-(2-furyl)-4-(1-naphthyl)-indenyl}]hafnium,
(20) dichloro[1,1'-dimethylsilylenebis(2-(2-furyl)-4-(2-naphthyl)-indenyl)]hafnium,
(21) dichloro[1,1'-dimethylsilylenebis(2-(2-furyl)-4-(2-phenanthryl)-indenyl)]hafnium,
(22) dichloro[1,1'-dimethylsilylenebis(2-(2-furyl)-4-(9-phenanthryl)-indenyl)]hafnium,
(23) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-biphenylyl)-indenyl}]hafnium,
(24) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(1-naphthyl)-indenyl}]hafnium,
(25) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(2-naphthyl)-indenyl}]hafnium,
(26) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(2-phenanthryl)-indenyl}]hafnium,
(27) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(9-phenanthryl)-indenyl}]hafnium,
(28) dichloro[1,1'-dimethylsilylenebis{2-(5-t-butyl-2-furyl)-4-(1-naphthyl)-indenyl}]hafnium,
(29) dichloro[1,1'-dimethylsilylenebis{2-(5-t-butyl-2-furyl)-4-(2-naphthyl)-indenyl}]hafnium,
(30) dichloro[1,1'-dimethylsilylenebis{(2-(5-t-butyl-2-furyl)-4-(2-phenanthryl)-indenyl)}hafnium,
(31) dichloro[1,1'-dimethylsilylenebis{2-(5-t-butyl-2-furyl)-4-(9-phenanthryl)-indenyl}]hafnium,
(32) dichloro[1,1′-dimethylsilylene(2-methyl-4-phenyl-indenyl){2-(5-methyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(33) Dichloro[1,1'-dimethylsilylene(2-methyl-4-phenyl-indenyl){2-(5-methyl-2-thienyl)-4-phenyl-indenyl}]hafnium, and the like.

Of these, more preferred are:
(3) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-phenyl-indenyl}]hafnium,
(13) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-chlorophenyl)-indenyl}]hafnium,
(16) dichloro[1,1′-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-isopropyl-phenyl)-indenyl}]hafnium,
(17) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-t-butylphenyl)-indenyl}]hafnium,
(18) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-trimethylsilylphenyl)-indenyl}]hafnium,
(23) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-biphenylyl)-indenyl}]hafnium,
(25) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(2-naphthyl)-indenyl}]hafnium,
It is.

Also particularly preferred are
(13) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-chlorophenyl)-indenyl}]hafnium,
(16) dichloro[1,1′-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-isopropyl-phenyl)-indenyl}]hafnium,
(17) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-t-butylphenyl)-indenyl}]hafnium,
(18) dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-trimethylsilylphenyl)-indenyl}]hafnium,
It is.

1-2. Component [A-2]
As the component [A-2] , a metallocene compound represented by the following general formula (a2) is preferably used.

[In general formula (a2), R ²¹ and R ²² each independently represent a hydrocarbon group having 1 to 6 carbon atoms. R ²³ and R ²⁴ each independently represent a halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or an aryl group having 6 to 30 carbon atoms which may contain a plurality of hetero elements selected therefrom. Q ²¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, or a silylene group or germylene group which may have a hydrocarbon group having 1 to 20 carbon atoms, M ²¹ represents zirconium or hafnium, and X ²¹ and Y ²¹ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silyl group having a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, an amino group, or an alkylamino group having 1 to 20 carbon atoms.]

The above R ²¹ and R ²² are each independently a hydrocarbon group having 1 to 6 carbon atoms, preferably an alkyl group, and more preferably an alkyl group having 1 to 4 carbon atoms. Specific examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, n-pentyl, i-pentyl, n-hexyl, and the like, and are preferably methyl, ethyl, or n-propyl.

Moreover, the above R ²³ and R ²⁴ are each independently an aryl group having 6 to 30 carbon atoms, preferably 6 to 24 carbon atoms, which may contain halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a plurality of hetero elements selected therefrom. Such aryl groups are phenyl groups, biphenylyl groups, and naphthyl groups, which may have a substituent. Preferred examples include phenyl, 3-chlorophenyl, 4-chlorophenyl, 3-fluorophenyl, 4-fluorophenyl, 4-methylphenyl, 4-i-propylphenyl, 4-t-butylphenyl, 4-trimethylsilylphenyl, 4-(2-fluoro-4-biphenylyl), 4-(2-chloro-4-biphenylyl), 1-naphthyl, 2-naphthyl, 4-chloro-2-naphthyl, 3-methyl-4-trimethylsilylphenyl, 3,5-dimethyl-4-t-butylphenyl, 3,5-dimethyl-4-trimethylsilylphenyl, and 3,5-dichloro-4-trimethylsilylphenyl.

^Q21 represents either a divalent hydrocarbon group having 1 to 20 carbon atoms that links two five-membered rings and bridges two conjugated five-membered ring ligands via a carbon having 1 or 2 carbon atoms, or a silylene group or germylene group that may have a hydrocarbon group having 1 to 20 carbon atoms. When two hydrocarbon groups are present on the above-mentioned silylene group or germylene group, they may be bonded to each other to form a ring structure.

Specific examples of ^Q21 include alkylene groups such as methylene, methylmethylene, dimethylmethylene, and 1,2-ethylene; aryl alkylene groups such as diphenylmethylene; silylene groups; alkyl silylene groups such as methylsilylene, dimethylsilylene, diethylsilylene, di(n-propyl)silylene, di(i-propyl)silylene, and di(cyclohexyl)silylene; (alkyl)(aryl)silylene groups such as methyl(phenyl)silylene; aryl silylene groups such as diphenylsilylene; alkyl oligosilylene groups such as tetramethyldisilylene; germylene groups; alkylgermylene groups in which the silicon of the silylene group having the above divalent hydrocarbon group having 1 to 20 carbon atoms is replaced with germanium; (alkyl)(aryl)germylene groups; and arylgermylene groups.
Among these, a silylene group having a hydrocarbon group of 1 to 20 carbon atoms or a germylene group having a hydrocarbon group of 1 to 20 carbon atoms is preferred, with an alkylsilylene group and an alkylgermylene group being particularly preferred.
Furthermore, the above ^M21 is zirconium or hafnium, and is preferably hafnium.

The above X ²¹ and Y ²¹ are auxiliary ligands, which react with the component (B) as a cocatalyst to produce an active metallocene having olefin polymerization ability. Therefore, as long as this purpose is achieved, the type of ligand for X ²¹ and Y ²¹ is not limited, and each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silyl group having a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group, or an alkylamino group having 1 to 20 carbon atoms.

Non-limiting examples of the metallocene compound represented by the above general formula (a2) include the following.
However, to avoid a cumbersome number of examples, only representative example compounds are described. Also, although compounds with hafnium as the central metal are described, similar zirconium compounds can also be used, and it is self-evident that various ligands, bridging groups, or auxiliary ligands can be used as desired.
(1) dichloro{1,1'-dimethylsilylenebis(2-methyl-4-phenyl-4-hydroazulenyl)}hafnium,
(2) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium,
(3) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-t-butylphenyl)-4-hydroazulenyl}]hafnium,
(4) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium,
(5) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(3-chloro-4-t-butylphenyl)-4-hydroazulenyl}]hafnium,
(6) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(3-methyl-4-t-butylphenyl)-4-hydroazulenyl}]hafnium,
(7) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(3-chloro-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium,
(8) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(3-methyl-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium,
(9) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(1-naphthyl)-4-hydroazulenyl}]hafnium,
(10) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(2-naphthyl)-4-hydroazulenyl}]hafnium,
(11) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chloro-2-naphthyl)-4-hydroazulenyl}]hafnium,
(12) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(2-fluoro-4-biphenylyl)-4-hydroazulenyl}]hafnium,
(13) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(2-chloro-4-biphenylyl)-4-hydroazulenyl}]hafnium,
(14) dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(9-phenanthryl)-4-hydroazulenyl}]hafnium,
(15) dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium,
(16) dichloro[1,1'-dimethylsilylenebis{2-n-propyl-4-(3-chloro-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium,
(17) dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(3-chloro-4-t-butylphenyl)-4-hydroazulenyl}]hafnium,
(18) dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(3-methyl-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium,
(19) dichloro[1,1'-dimethylgermylenebis{2-methyl-4-(2-fluoro-4-biphenylyl)-4-hydroazulenyl}]hafnium,
(20) dichloro[1,1'-dimethylgermylenebis{2-methyl-4-(4-t-butylphenyl)-4-hydroazulenyl}]hafnium,
(21) dichloro[1,1'-(9-silafluorene-9,9-diyl)bis{2-ethyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium,
(22) dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(4-chloro-2-naphthyl)-4-hydroazulenyl}]hafnium,
(23) dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(2-fluoro-4-biphenylyl)-4-hydroazulenyl}]hafnium,
(24) Dichloro[1,1'-(9-silafluorene-9,9-diyl)bis{2-ethyl-4-(3,5-dichloro-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium, and the like.

Among these, dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium, dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(3-chloro-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium, dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(2-fluoro-4-biphenylyl)-4-hydroazulenyl}]hafnium, dichloro[1, 1'-dimethylsilylenebis{2-ethyl-4-(4-chloro-2-naphthyl)-4-hydroazulenyl}]hafnium, dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(3-methyl-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium, dichloro[1,1'-(9-silafluorene-9,9-diyl)bis{2-ethyl-4-(3,5-dichloro-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium.

Particularly preferred are dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium, dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(2-fluoro-4-biphenylyl)-4-hydroazulenyl}]hafnium, dichloro[1,1'-dimethylsilylenebis{2-ethyl-4-(3-methyl-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium, and dichloro[1,1'-(9-silafluorene-9,9-diyl)bis{2-ethyl-4-(3,5-dichloro-4-trimethylsilylphenyl)-4-hydroazulenyl}]hafnium.

2. Catalyst Component (B)
The catalyst component (B) used in the present invention is a compound or an ion-exchangeable layered silicate which reacts with the catalyst component (A) to form an ion pair.
The catalyst component (B) may be used alone or in combination of two or more thereof, and is preferably an ion-exchangeable layered silicate.

2-1. Compounds that form ion pairs with catalyst component (A) Examples of compounds that react with catalyst component (A) to form ion pairs include aluminum oxy compounds and boron compounds. Specific examples of aluminum oxy compounds include compounds represented by the following general formulas (I) to (III).

In the above general formulas (I), (II) and (III), R ⁹¹ , R ¹⁰¹ and R ¹¹¹ each represent a hydrogen atom or a hydrocarbon group, preferably a hydrocarbon group having 1 to 10 carbon atoms, and particularly preferably a hydrocarbon group having 1 to 6 carbon atoms. Furthermore, multiple R ⁹¹ , R ¹⁰¹ and R ¹¹¹ may be the same or different. Furthermore, p represents an integer of 0 to 40, preferably 2 to 30.
The compounds represented by the general formulas (I) and (II) are also called aluminoxanes, and among them, methylaluminoxane or methylisobutylaluminoxane is preferred. The above aluminoxanes can be used in combination of multiple types within each group or between each group. The above aluminoxanes can be prepared under various known conditions.
In general formula (III), R ¹¹² represents a hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. The compound represented by general formula (III) can be obtained by reacting one type of trialkylaluminum or two or more types of trialkylaluminum with an alkylboronic acid represented by general formula R ¹¹² B(OH) ₂ in a molar ratio of 10:1 to 1:1.
Examples of the boron compound include complexes of cations such as carbonium cation and ammonium cation with organic boron compounds such as triphenyl boron, tris(3,5-difluorophenyl) boron and tris(pentafluorophenyl) boron, and various organic boron compounds such as tris(pentafluorophenyl) boron.

In the present invention, the ion-exchangeable layered silicate (hereinafter, sometimes simply referred to as silicate) used as a raw material refers to a silicate compound having a crystal structure in which layers formed by ionic bonds or the like are stacked in parallel with each other through bonding forces, having interlayer ions between the layers, and in which the contained interlayer ions are exchangeable.
Most silicates are naturally produced as the main component of clay minerals. They are generally purified by dispersing/swelling them in water and measuring the difference in sedimentation rate, but it is not necessary to completely remove impurities, and they may contain impurities other than ion-exchangeable layered silicates (quartz, cristobalite, etc.). Depending on the type, amount, particle size, crystallinity, and dispersion state of these impurities, they may be more preferable than pure silicates, and such complexes are also included in the ion-exchangeable layered silicates of the catalyst component (B).
Moreover, the silicate used in the present invention is not limited to naturally occurring silicates, but may be synthetically produced silicates.

Specific examples of ion-exchangeable layered silicates include layered silicates having a 1:1 type structure or a 2:1 type structure, as described in, for example, "Clay Mineralogy" by Shiramizu Haruo, Asakura Publishing (1988).
The 1:1 type structure refers to a structure based on stacking of one layer of tetrahedral sheet and one layer of octahedral sheet, as described in the above-mentioned "Clay Mineralogy" and the like.
The 2:1 type structure refers to a structure based on stacking two layers of tetrahedral sheets sandwiching one layer of octahedral sheet.
Specific examples of ion-exchangeable layered silicates having a 1:1 type structure include kaolin group silicates such as dickite, nacrite, kaolinite, metahalloysite, and halloysite, and serpentine group silicates such as chrysotile, lisardite, and antigorite.
Specific examples of ion-exchangeable layered silicates having a 2:1 type structure include smectite group silicates such as montmorillonite, beidellite, nontronite, saponite, hectorite, stevensite, etc., vermiculite group silicates such as vermiculite, mica group silicates such as mica, illite, sericite, glauconite, etc., attapulgite, sepiolite, palygorskite, bentonite, pyrophyllite, talc, chlorite group, etc. These may form mixed layers.
Among these, it is preferable that the main component is an ion-exchangeable layered silicate having a 2:1 type structure, more preferably that the main component is a smectite group silicate, and even more preferably that the main component is montmorillonite.
The type of interlayer cation (the positive ion contained between the layers of the ion-exchangeable layered silicate) is not particularly limited, but preferred main components are alkali metals of Group 1 of the periodic table, such as lithium and sodium, alkaline earth metals of Group 2 of the periodic table, such as calcium and magnesium, and transition metals, such as iron, cobalt, copper, nickel, zinc, ruthenium, rhodium, palladium, silver, iridium, platinum, and gold, which are relatively easily available.

The ion-exchangeable layered silicate may be used in a dry state or in a slurried state in a liquid.
The shape of the ion-exchangeable layered silicate is not particularly limited, and may be a naturally occurring shape or a shape at the time of artificial synthesis, or may be an ion-exchangeable layered silicate whose shape has been processed by operations such as pulverization, granulation, and classification.
Among these, the use of granulated ion-exchange layered silicate is particularly preferred because it gives good polymer particle properties when the ion-exchange layered silicate is used as a catalyst component.
The ion-exchanged layered silicate can be used as it is without any particular treatment, but it is preferable to subject it to a chemical treatment. For the chemical treatment method of the ion-exchanged layered silicate, see paragraphs 0042 to 0071 of JP 2009-299046 A.

The catalyst component (B) preferably used in the present invention is a chemically treated ion-exchangeable layered silicate having an Al/Si atomic ratio of 0.01 to 0.25, preferably 0.03 to 0.24, and more preferably 0.05 to 0.23. The Al/Si atomic ratio is considered to be an index of the acid treatment strength of the clay portion.
The aluminum and silicon in the ion-exchangeable layered silicate are measured by preparing a calibration curve according to a chemical analysis method in accordance with the JIS method, and quantifying the amounts by fluorescent X-rays.

3. Component (C)
The catalyst component (C) used in the present invention is an organoaluminum compound, and preferably an organoaluminum compound represented by the following general formula (IV) is used.
(AlR _n X _3-n ) _m General formula (IV)
[In the above general formula (IV), R represents an alkyl group having 1 to 20 carbon atoms, X represents a halogen, a hydrogen, an alkoxy group, or an amino group, n represents an integer of 1 to 3, and m represents an integer of 1 or 2.]
When X is a halogen, it is preferably chlorine; when X is an alkoxy group, it is preferably an alkoxy group having 1 to 8 carbon atoms; and when X is an amino group, it is preferably an amino group having 1 to 8 carbon atoms.
The organoaluminum compounds may be used alone or in combination of two or more kinds.
Specific examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, tri-normal propylaluminum, tri-normal butylaluminum, triisobutylaluminum, tri-normal hexylaluminum, tri-normal octylaluminum, tri-normal decylaluminum, diethylaluminum chloride, diethylaluminum sesquichloride, diethylaluminum hydride, diethylaluminum ethoxide, diethylaluminum dimethylamide, diisobutylaluminum hydride, diisobutylaluminum chloride, etc. Among these, preferred are trialkylaluminums and alkylaluminum hydrides in which m=1 and n=3. More preferred are trialkylaluminums in which R has 1 to 8 carbon atoms.

4. Preparation of Catalyst The olefin polymerization catalyst used in the present invention contains the above-mentioned catalyst components. These can be obtained by contacting them in or outside a polymerization vessel. The olefin polymerization catalyst may be prepolymerized in the presence of an olefin.
The contact of the catalyst components is usually carried out in an aliphatic or aromatic hydrocarbon solvent. The contact temperature is not particularly limited, but is preferably between -20°C and 150°C. The contact order may be any combination suitable for the purpose, but the particularly preferred order for each catalyst component is as follows:
When using catalyst component (C), it is possible to contact catalyst component (C) with catalyst component (A), or with catalyst component (B), or with both catalyst component (A) and catalyst component (B) before contacting catalyst component (A) with catalyst component (B), or to contact catalyst component (C) with catalyst component (A) and catalyst component (B) at the same time as contacting catalyst component (A) with catalyst component (B), or to contact catalyst component (C) after contacting catalyst component (A) with catalyst component (B). Preferably, catalyst component (C) is contacted with either catalyst component (A) or catalyst component (B) before contacting catalyst component (A) with catalyst component (B).
After contacting the catalyst components, they can be washed with an aliphatic hydrocarbon or aromatic hydrocarbon solvent.

The amounts of the catalyst components (A), (B) and (C) used in the present invention are arbitrary. For example, the amount of the catalyst component (A) used relative to the catalyst component (B) is preferably in the range of 0.1 μmol to 1000 μmol, more preferably 0.5 μmol to 500 μmol, per 1 g of the catalyst component (B).
The amount of catalyst component (C) used relative to catalyst component (A) is preferably in the range of 0.01 to 5 x 10 ⁶ , more preferably 0.1 to 1 x 10 ⁴ , in terms of the molar ratio of aluminum of catalyst component (C) to the transition metal of catalyst component (A).

The branched polypropylene-based polymer of the present invention can be produced by using a catalyst component capable of producing a macromer and a catalyst component capable of copolymerizing the macromer with propylene. Although it is possible to produce the polymer by using a single catalyst component having both the ability to produce the macromer and the ability to copolymerize the macromer with propylene, a method using separate catalyst components having each of the respective capabilities can be selected to efficiently produce the branched polypropylene-based polymer of the present invention. That is, the method using a component [A-1] capable of producing a macromer and a component [A-2] capable of copolymerizing the macromer with propylene makes it easy to produce a branched polypropylene-based polymer satisfying the requirements of the present invention.
The proportions of the components [A-1] and [A-2] used may be any as long as the branched polypropylene polymer of the present invention satisfies the required properties. However, the molar ratio of the transition metal in [A-1] to the total amount of the components [A-1] and [A-2] is preferably 0.30 or more and 0.99 or less.
By changing this ratio, it is possible to adjust the balance between melt properties and catalytic activity. That is, from component [A-1], a low molecular weight vinyl-terminated macromer is produced, and from component [A-2], a high molecular weight product in which a part of the macromer is copolymerized is produced. Therefore, by changing the ratio of component [A-1], it is possible to control the average molecular weight, molecular weight distribution, the bias of the molecular weight distribution toward the low molecular weight side, the very high molecular weight component, and the branching (amount, length, distribution) of the produced polymer, and thereby it is possible to control melt properties such as the strain hardening degree, melt tension, and elongational viscosity.
The molar ratio of the transition metal in component [A-1] to the total amount of components [A-1] and [A-2] is preferably 0.30 or more, more preferably 0.40 or more, and even more preferably 0.50 or more. The upper limit is preferably 0.90 or less, and in order to efficiently obtain the polymer of the present invention with high catalytic activity, the upper limit is preferably 0.80 or less, and even more preferably 0.70 or less.
Furthermore, by using the component [A-1] within the above range, it is possible to adjust the balance between the average molecular weight and the catalytic activity relative to the amount of hydrogen.

5. Prepolymerization The olefin polymerization catalyst is preferably subjected to prepolymerization, which involves contacting an olefin and polymerizing a small amount of the olefin. By carrying out the prepolymerization treatment, it is possible to prevent the formation of gel when carrying out the main polymerization. The reason for this is believed to be that long chain branches can be uniformly distributed among the polymer particles when carrying out the main polymerization.
The olefin used in the prepolymerization is not particularly limited, but examples thereof include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, and styrene, and is preferably propylene.
The olefin may be fed to the prepolymerization reactor at a constant rate or at a constant pressure, or any combination thereof, or by stepwise change.

The prepolymerization temperature and prepolymerization time are not particularly limited, but are preferably in the range of -20°C to 100°C and 5 minutes to 24 hours, respectively.
The amount of the prepolymerization is preferably 0.01 to 100, more preferably 0.1 to 50, in terms of the mass ratio of the prepolymerized polymer to the catalyst component (B).
In addition, the catalyst component (C) can be added during the prepolymerization, and washing can also be carried out at the end of the prepolymerization.
It is also possible to use a method in which a polymer such as polyethylene or polypropylene or a solid inorganic oxide such as silica or titania is made to coexist during or after the contact of the above catalyst components.
After the preliminary polymerization, the catalyst may be dried. The drying method is not particularly limited, and examples thereof include drying under reduced pressure, drying by heating, and drying by passing a dry gas through the catalyst. These methods may be used alone or in combination of two or more methods. In the drying step, the catalyst may be stirred, vibrated, or fluidized.

6. Propylene Polymerization Any polymerization mode can be adopted as long as the olefin polymerization catalyst and the monomer are efficiently contacted with each other.
Specifically, a slurry polymerization method using an inert solvent, a bulk polymerization method using propylene as a solvent without substantially using an inert solvent, a solution polymerization method, or a gas phase polymerization method in which each monomer is kept in a gaseous state without substantially using a liquid solvent can be used.
Furthermore, a method of carrying out continuous polymerization or batch polymerization can also be applied.
Besides single-stage polymerization, multi-stage polymerization of two or more stages is also possible.

In the case of the slurry polymerization method, as the inert solvent, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene, toluene, etc., may be used alone or in mixture.
The polymerization temperature is preferably 0° C. or higher and 150° C. or lower. In particular, in the case of a bulk polymerization method, the polymerization temperature is more preferably 40° C. or higher, and even more preferably 50° C. or higher. The upper limit is preferably 80° C. or lower, and even more preferably 75° C. or lower.
In the case of the gas phase polymerization method, the temperature is preferably 40° C. or higher, more preferably 50° C. or higher, and the upper limit is preferably 100° C. or lower, more preferably 90° C. or lower.

The polymerization pressure is preferably 1.0 MPa or more and 5.0 MPa or less. In particular, in the case of a bulk polymerization method, it is more preferably 1.5 MPa or more, and even more preferably 2.0 MPa or more. The upper limit is preferably 4.0 MPa or less, and even more preferably 3.5 MPa or less.
In the case of the gas phase polymerization method, the pressure is preferably 1.5 MPa or more, more preferably 1.7 MPa or more, and the upper limit is preferably 2.5 MPa or less, more preferably 2.3 MPa or less.

Furthermore, in order to produce the branched polypropylene polymer of the present invention, it is preferable to use hydrogen as a molecular weight modifier in a range of 1.0×10 ⁻⁵ or more and 1.0×10 ⁻² or less in terms of molar ratio to propylene.
For example, the polymer produced from the above-mentioned component [A-1] has a very slow chain transfer due to hydrogen, while the polymer produced from the component [A-2] has a relatively fast chain transfer due to hydrogen, and when there is a small amount of hydrogen, a high molecular weight can be produced, but when there is a large amount of hydrogen, the molecular weight of the produced polymer decreases. Therefore, when the amount of hydrogen used is small, the polymer produced from the component [A-2] exists on the higher molecular weight side than the polymer produced from the component [A-1], but when the amount of hydrogen used is large, the polymer produced from [A-2] exists more on the lower molecular weight side than the polymer produced from the component [A-1].
Furthermore, component [A-1] produces vinyl-terminated macromers, which are then copolymerized with component [A-1] to produce branched polymers. On the other hand, component [A-2] does not produce macromers by itself, but only when the macromer produced by component [A-1] approaches component [A-2] does it copolymerize to produce branched polymers. In other words, due to the difference in contact efficiency with vinyl-terminated macromers, the branch density of the polymer derived from component [A-2] is lower than that of the polymer derived from component [A-1].
Therefore, by using a large amount of hydrogen in the method for producing the branched polypropylene of the present invention, it is possible to broaden the molecular weight distribution to the low molecular weight side so that the polymer produced from component [A-2] is more abundant on the low molecular weight side than the polymer produced from component [A-1], and to reduce the branching density on the low molecular weight side. On the other hand, by having a large amount of polymer derived from component [A-1] on the high molecular weight side, it is possible to make the branching density on the high molecular weight side fall within a specific range. As a result, it is possible to make the g' at each absolute molecular weight, as the branching distribution, fall within a specific range as shown for the branched polypropylene of the present invention.
Therefore, hydrogen is used in a molar ratio to propylene of 1.0×10 ⁻⁵ or more, preferably 1.0×10 ⁻⁴ or more, and more preferably 0.5×10 ⁻³ or more. The upper limit is 1.0×10 ⁻² or less, preferably 0.5×10 ⁻² or less, and more preferably 0.2×10 ⁻² or less.

III. Uses of the branched polypropylene polymer The branched polypropylene polymer of the present invention can be used as a molding material after being heated, melt-kneaded using a melt kneader, and then cut into pellets. The branched polypropylene polymer of the present invention can be blended with various additives such as known antioxidants, ultraviolet absorbers, antistatic agents, nucleating agents, lubricants, flame retardants, antiblocking agents, colorants, inorganic or organic fillers, and various synthetic resins, as necessary.
These pellet-like molding materials can be molded by various known polypropylene molding methods, such as injection molding, extrusion molding, foam molding, and blow molding, to produce various molded products such as industrial injection molded parts, containers, non-oriented films, uniaxially oriented films, biaxially oriented films, sheets, pipes, and fibers.
In addition, the branched polypropylene-based polymer of the present invention has an excellent balance between melt fluidity and elongational viscosity, and therefore can be suitably used in fields requiring uniform wall thickness in sheet molding, blow molding, etc., uniform foam cell diameter in foam molding, etc., and fine fiber diameter in melt spinning, etc.
The branched polypropylene polymer of the present invention can also be used by blending it with other resins.

Next, the present invention will be explained in more detail using examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[Example 1]
(1) Synthesis of Complex (1-a) Synthesis of rac-dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-i-propylphenyl)indenyl}]hafnium:
rac-Dichloro[1,1′-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-i-propylphenyl)indenyl}]hafnium was synthesized according to the method of Synthesis Example 1 in JP 2012-149160 A.
(1-b) Synthesis of rac-dichloro[1,1′-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium:
rac-Dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium was synthesized according to the method of Example 7 of JP-A-11-240909.

(2) Preparation of Catalyst (2-a) Chemical Treatment of Ion-Exchangeable Layered Silicate Into a 1 L three-neck flask equipped with a stirring blade and a reflux device, 645.1 g of distilled water and 82.6 g of 98% sulfuric acid were added and heated to 95°C.
100 g of commercially available montmorillonite (Benclay KK, manufactured by Mizusawa Chemical Industries, Ltd., Al=9.78% by mass, Si=31.79% by mass, Mg=3.18% by mass, Al/Si (molar ratio)=0.320, average particle size 14 μm) was added thereto, and the mixture was reacted for 320 minutes at 95° C. After 320 minutes, 0.5 L of distilled water was added to stop the reaction, and the mixture was filtered to obtain 255 g of a cake-like solid.
This cake contained 0.31 g of the chemically treated montmorillonite (intermediate), which had a chemical composition of Al = 7.68 mass%, Si = 36.05 mass%, Mg = 2.13 mass%, and Al/Si (molar ratio) = 0.222.
1,545 g of distilled water was added to the cake to form a slurry, and the temperature was raised to 40° C. 5.734 g of lithium hydroxide hydrate was added as a solid, and the mixture was reacted for 1 hour at 40° C. After 1 hour, the reaction slurry was filtered and washed three times with 1 L of distilled water, again obtaining a cake-like solid.
The collected cake was dried to obtain 80 g of chemically treated montmorillonite, which had a chemical composition of Al = 7.68 mass%, Si = 36.05 mass%, Mg = 2.13 mass%, Al/Si (molar ratio) = 0.222, and Li = 0.53 mass%.

(2-b) Prepolymerization In a reactor having an internal volume of ¹ m3, 150 kg of the chemically treated montmorillonite obtained as described above was placed, and 2832 L of hexane was added to form a slurry, to which 74.4 kg (375 mol) of triisobutylaluminum was added over 85 minutes and stirred for 60 minutes. After that, the mixture was washed with hexane to 1/32 of its volume, and the total volume was adjusted to 900 L.
The slurry solution containing the chemically treated montmorillonite was kept at 50° C., and 0.65 kg of triisobutylaluminum (4.257 kg, 3.28 mol, of a hexane solution with a concentration of 15.3% by mass) was added thereto.
After stirring for 5 minutes, 0.657 kg (0.81 mol) of rac-dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium and 96 L of toluene were added, and stirring was continued for 60 minutes.
Thereafter, 9.758 kg (26.61 mol) of tri-normal octylaluminum was added and stirred for 6 minutes, and then, in another vessel equipped with a stirrer, a solution prepared by adding 1.768 kg (1.89 mol) of rac-dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-i-propylphenyl)indenyl}]hafnium to 0.064 kg (9.88 kg, 0.32 mol) of triisobutylaluminum in 240 L of toluene was added, and 100 L of toluene was added, and stirring was continued for another 20 minutes.
Thereafter, 2387 L of hexane was added, and the internal temperature of the reactor was raised to 40° C., after which 328.1 kg of propylene was fed over 240 minutes to carry out prepolymerization while maintaining the temperature at 40° C. Thereafter, the propylene feed was stopped, and residual polymerization was carried out for 80 minutes while maintaining the temperature at 40° C.
After the completion of the residual polymerization, the stirring was stopped, and the contents were allowed to settle and settle. The supernatant was removed until the solution volume was 1500 L, 12.7 kg of triisobutylaluminum was added, 3974 L of hexane was added again, and the mixture was stirred, then allowed to settle and settle, and the supernatant was removed until the solution volume was 1500 L.
To this was added 8.9 kg of triisobutylaluminum (42.9 kg of a hexane solution having a concentration of 20.8% by mass) and 205 L of hexane.
Thereafter, the reaction liquid was transferred to a dryer and dried at 40° C. for 9 hours.
As a result, 465 kg of a dry prepolymerized catalyst was obtained. The prepolymerization ratio (amount of prepolymerized polymer divided by amount of solid catalyst) was 2.1. This prepolymerized catalyst was designated as Catalyst 1.

(3) Polymerization A 20L autoclave was dried thoroughly in advance by passing nitrogen through it under heating, and then the inside of the tank was replaced with propylene and cooled to room temperature. 18.7 mL of a heptane solution of triisobutylaluminum (140 mg/mL) and 1.45 N (normal) L of _H2 were introduced, followed by 5000 g of liquid propylene, and the temperature was raised to 63 ° C. Then, 150 mg of the catalyst 1, excluding the prepolymerized polymer, was pumped into the polymerization tank with high-pressure argon to start polymerization, and the temperature was quickly raised to 70 ° C. The temperature was kept at 70 ° C., and after 1 hour from the start of polymerization, the unreacted propylene was quickly purged to stop the polymerization. As a result, about 1804 g of propylene homopolymer was obtained. The evaluation results of the obtained polymer are shown in Table 1.

(4) Granulation 100 parts by weight of the obtained branched propylene polymer were blended with 0.125 parts by weight of a phenol-based antioxidant IRGANOX1010 (trade name, manufactured by BASF Japan, tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane) and 0.125 parts by weight of a phosphite-based antioxidant IRGAFOS168 (trade name, manufactured by BASF Japan, tris(2,4-di-t-butylphenyl)phosphite), and mixed at room temperature for 3 minutes using a high-speed stirring mixer Henschel Mixer (trade name, manufactured by Nippon Coke & Engineering Co., Ltd.). Thereafter, the mixture was melt-kneaded using a twin-screw extruder KZW-15 (manufactured by Technobel Co., Ltd.) at a screw rotation speed of 400 rpm and a kneading temperature of 80, 120, and 230°C from the bottom of the hopper (the same temperature from then until the die outlet). The molten resin extruded from the strand die was taken up while being cooled and fixed in a cooling water tank, and the strands were cut and pelletized using a strand cutter.

[Examples 2 to 4]
In the polymerization of Example 1 (3), the amount of H ₂ introduced was changed to 1.70 NL, 2.30 NL, or 2.81 NL, and the amount of catalyst 1 was changed to 140 mg, 130 mg, or 130 mg, respectively. The same polymerization as in Example 1 was performed.
The evaluation results of the obtained polymer are shown in Table 1.
Each of the obtained branched propylene polymers was granulated in the same manner as in Example 1 and pelletized.

[Comparative Examples 1 to 4]
A molecular weight reducing agent Perbutyl P-40 (trade name, NOF Corp. organic peroxide, α,α'-di(t-butylperoxy)diisopropylbenzene) was blended with a linear polymer propylene homopolymer FY6Q (trade name, Japan Polypropylene Corp., MFR = 3g / 10 min, Tm = 160 ° C., g' = 1.00), and the mixture was stirred and mixed for 3 minutes with a high-speed stirring mixer Henschel Mixer (trade name, Nippon Coke & Engineering Co., Ltd.). Thereafter, the mixture was melt-kneaded using a twin-screw extruder KZW-15 (Technovel Corp., screw diameter 15 mm) at a screw rotation speed of 400 rpm and a kneading temperature of 80, 120, and 230 ° C. from the bottom of the hopper (hereafter, the same temperature until the die outlet). The molten resin extruded from the strand die was taken while being cooled and fixed in a cooling water tank, and the strands were cut and pelletized using a strand cutter.
By adjusting the amount of the molecular weight reducing agent, pellets of linear polymers having MFR=182 (Comparative Example 1), 296 (Comparative Example 2), 470 (Comparative Example 3) and 660 (Comparative Example 4) g/10 min were obtained.

[Physical property measurement and analysis]
The physical property measurements and analyses in the examples and comparative examples were performed according to the following methods. The results of the physical property measurements and analyses are shown in Table 1.
(1) Melt flow rate (MFR):
The melt flow rate was measured according to JIS K7210, a polypropylene testing method (test conditions: 230° C., load 2.16 kgf) in g/10 min.
(2) Molecular weight and molecular weight distribution (Mw, Mn, Mw/Mn, wL/wH, _W1M ):
The measurement was performed by gel permeation chromatography (GPC) using the method described in the present specification above.
(3) 3D-GPC (g'(M _abs pt), g'(Mw _abs ), g'(Mz _abs ), g'(1M))
As the GPC apparatus to which a differential refractometer (RI), a viscosity detector (Viscometer) and a multi-angle laser light scattering detector (MALLS) were connected, a GPC apparatus (Alliance GPCV2000, manufactured by Waters) equipped with a differential refractometer (RI) and a viscosity detector (Viscometer) and a multi-angle laser light scattering detector (DAWN-E, manufactured by Yatt Technology) were used, and the measurement was performed by the method described in the present specification.

(4) Determination of the regularity of the side chain and main chain (4-1) Example of the homopolymerization method of the side chain (4-1-a) Preparation of catalyst and preliminary polymerization 20 g of the chemically treated montmorillonite obtained in Example 1 was placed in a 1 L three-neck flask, and 131 mL of heptane was added to make a slurry, to which 50 mmol of triisobutylaluminum (69 mL of a heptane solution with a concentration of 143.4 mg/mL) was added and stirred for 60 minutes. After that, the mixture was washed with heptane to 1/100, and the total volume was made 100 mL.
The slurry solution containing the chemically treated montmorillonite was kept at 50° C., and 4.2 mmol of tri-n-octylaluminum (10.7 mL of a heptane solution having a concentration of 143.4 mg/mL) was added thereto, followed by stirring for 20 minutes.
To this was added 0.3 mmol of rac-dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-i-propylphenyl)indenyl}]hafnium synthesized in Example (1-a) (prepared as a slurry with 50 mL of toluene), and the mixture was stirred for 20 minutes while maintaining the temperature at 50°C.
Then, 350 mL of heptane was added, and the slurry was introduced into a 1 L autoclave.
After the internal temperature of the autoclave was raised to 40° C., propylene was fed at a rate of 10 g/hour, and prepolymerization was carried out for 4 hours while maintaining the temperature at 40° C. Thereafter, the propylene feed was stopped, and residual polymerization was carried out for 1 hour while maintaining the temperature at 40° C.
The supernatant of the obtained catalyst slurry was removed by decantation, and then heptane was added again and decanted to wash the prepolymerized catalyst. 12 mmol of triisobutylaluminum (16.6 mL of a heptane solution with a concentration of 143.4 mg/mL) was added to the portion remaining after the decantation, and the mixture was stirred for 10 minutes. The solid was dried under reduced pressure at 40° C. for 2 hours to obtain 54.0 g of a dried prepolymerized catalyst. The prepolymerization ratio (the value obtained by dividing the amount of prepolymerized polymer by the amount of solid catalyst) was 1.7. This prepolymerized catalyst was designated as catalyst 2.
(4-1-b) Polymerization A 3L autoclave was thoroughly dried in advance by passing nitrogen through it under heating, and then the inside of the vessel was replaced with propylene and cooled to room temperature. 2.86 mL of a heptane solution of triisobutylaluminum (140 mg/mL) and 750 g of liquid propylene were introduced, and the temperature was raised to 70°C. Then, 200 mg of the catalyst 2, excluding the prepolymerized polymer, was pumped into the polymerization vessel and polymerized at 70°C for 1 hour. Finally, the unreacted propylene was quickly purged to stop the polymerization. As a result, about 350 g of a propylene homopolymer having an MFR of 40 was obtained.

(4-2) Example of Main Chain Homopolymerization Method (4-2-a) Preparation of Catalyst and Prepolymerization In a 1 L three-neck flask, 20 g of the chemically treated montmorillonite obtained in Example 1 was placed, and 131 mL of heptane was added to make a slurry, to which 50 mmol of triisobutylaluminum (69 mL of a heptane solution with a concentration of 143.4 mg/mL) was added and stirred for 60 minutes. After that, the mixture was washed with heptane to 1/100, and the total volume was adjusted to 100 mL.
This slurry solution containing the chemically treated montmorillonite was kept at 50° C., and 4.2 mmol of tri-n-octylaluminum (10.6 mL of a heptane solution having a concentration of 145.0 mg/mL) was added thereto, followed by stirring for 20 minutes.
To this was added 0.3 mmol of rac-dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium synthesized in Example (1-b) (prepared as a slurry with 50 mL of toluene), and the mixture was stirred for 20 minutes while maintaining the temperature at 50°C.
Then, 350 mL of heptane was added, and the slurry was introduced into a 1 L autoclave.
After the internal temperature of the autoclave was raised to 40° C., propylene was fed at a rate of 10 g/hour, and prepolymerization was carried out for 4 hours while maintaining the temperature at 40° C. Thereafter, the propylene feed was stopped, and residual polymerization was carried out for 1 hour while maintaining the temperature at 40° C.
The supernatant of the obtained catalyst slurry was removed by decantation, and then heptane was added again and decanted to wash the prepolymerized catalyst. 12 mmol of triisobutylaluminum (16.6 mL of a heptane solution with a concentration of 143.4 mg/mL) was added to the portion remaining after the decantation, and the mixture was stirred for 10 minutes. The solid was dried under reduced pressure at 40° C. for 2 hours to obtain 62.2 g of a dried prepolymerized catalyst. The prepolymerization ratio (the value obtained by dividing the amount of prepolymerized polymer by the amount of solid catalyst) was 2.1. This prepolymerized catalyst was designated as catalyst 3.
(4-2-b) Polymerization Polymerization was carried out in the same manner as in (4-1-b) above, except that 240 mL of _H2 was further introduced before the introduction of 750 g of liquid propylene, and 30 mg of the catalyst 3 was used instead of the catalyst 2. As a result, about 157 g of a propylene homopolymer having an MFR of 1.0 was obtained.
(4-3) Determination of the Regularity of the Main Chain and the Side Chain The regularity of the main chain and the side chain was determined by using the homopolymer of the main chain and the side chain obtained above according to the method described in the present specification.

(5) Melting point (Tm), crystallization temperature (Tc):
The branched polypropylene polymer powder was sandwiched between press plates, preheated at 190° C. for 2 minutes, and pressed at 5 MPa for 2 minutes, then cooled at 0° C. and 10 MPa for 2 minutes to obtain a sheet.
Using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.), 5 mg of a sample piece of the sheet obtained above was packed into an aluminum pan, and the temperature was raised from room temperature to 200°C at a heating rate of 100°C/min, held for 5 minutes, and then cooled to 20°C at a rate of 10°C/min to determine the crystallization temperature (Tc) as the maximum crystallization peak temperature (°C) at which crystallization occurred. Thereafter, the temperature was raised to 200°C at a rate of 10°C/min to determine the melting point (Tm) as the maximum melting peak temperature (°C).
(6) Components eluted at 40° C. or less Measured by temperature rising elution fractionation (TREF) using the method described in the present specification above. The unit is weight %.
(7) Shear viscosity, extensional viscosity:
Based on JIS K7199, the shear viscosity and extensional viscosity were measured. Using a capillary rheometer (twin capillary rheometer RH2200, manufactured by Rosand), 26 g of weighed sample pellets were placed in two barrels, the temperature was raised, and the sample pellets were melted while degassing the air in the sample, and the pellets were held at 180 ° C for 10 minutes and measured under the following conditions. Using analysis software Flowmaster (manufactured by Rosand), a graph of the extensional viscosity and a graph of the shear viscosity were obtained by performing correction for the pressure loss caused by the capillary die (Burgeley correction) and Rabinovich correction from the measured data. The extensional viscosity at an extension rate of 300 / s was obtained.
Barrel diameter: 15mm
Barrel length: 250mm
Capillary die material: tungsten carbide Capillary die: diameter 1 mm, length 16 mm, inlet angle 180°
and diameter 1 mm, length 0 mm, inflow angle 180°
Measurement mode: Twin capillary mode

The relationship between MFR and extensional viscosity is shown in Figure 3. Examples 1 to 4 and Comparative Examples 1 to 4 show that the branched polypropylene polymer of the present invention has an improved balance between MFR (melt fluidity) and extensional viscosity.

Claims (5)

A branched polypropylene-based polymer having the following properties (2) to (5) and (10):
Property (2): The weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) is 50,000 or more and 160,000 or less, and the ratio (Q value) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.0 or more and 4.5 or less.
Property (3): In a molecular weight distribution curve obtained by GPC, when the common logarithm of the molecular weight corresponding to the peak position is Tp, the common logarithms of the molecular weight at a position corresponding to 20% of the peak height are L ₂₀ and H ₂₀ (L ₂₀ is on the lower molecular weight side than Tp, and H ₂₀ is on the higher molecular weight side than Tp), and wL=Tp-L ₂₀ and wH=H ₂₀ -Tp, wL/wH is 1.15 or more and 1.50 or less.
Property (4): In an integrated molecular weight distribution curve obtained by GPC, the proportion of components having a molecular weight of 1,000,000 or more (W _1M ) is 0.1% by weight or more and less than 2.5% by weight.
Property (5): In the molecular weight distribution curve obtained by 3D-GPC,
There is a relationship of M _abs pt < Mw _abs < Mz _abs < 1 million,
The branching index g' (M _abs pt) at M _abs pt is 0.90 or more and 1.00 or less; the branching index g' (Mw _abs ) at Mw _abs is 0.88 or more and less than 1.00; the branching index g' (Mz _abs ) at Mz _abs is 0.75 or more and less than 0.88; and the branching index g' (1M) at an absolute molecular weight M _abs of 1 million is 0.70 or more and 0.81 or less.
Here, M _abs pt, Mw _abs and Mz _abs respectively represent the absolute molecular weight, the weight average molecular weight and the z-average molecular weight corresponding to the peak position.
Property (10):
The extensional viscosity (unit: kPa s) at an extension rate of 300/s, measured according to the provisions of JIS K7199, and the melt flow rate (MFR) (unit: g/10 min) measured at a temperature of 230°C under a load of 2.16 kg satisfy the relationship represented by the following formula (4).
log(616)≧log(MFR)＞(−log(extension viscosity at extension rate of 300/s)+3.30)/1.44 (4) The branched polypropylene-based polymer according to claim 1, further having the following property (6):
Property (6): The branched polypropylene-based polymer has a side chain and a main chain,
the mesopentad fraction (mmmm) of the side chains measured by ^13C -NMR is in the range of 96% or more and less than 98%, the amount of hetero bonds (2,1 bonds) is in the range of 0 mol% or more and less than 0.30 mol%, and the amount of hetero bonds (1,3 bonds) is in the range of 0.05 mol% or more and less than 0.20 mol%,
The main chain has a mesopentad fraction (mmmm) measured by ¹³ C-NMR of 98% or more and less than 99%, a heterogeneous bond amount (2,1 bond) of 0.30 mol % or more and 1.00 mol % or less, and a heterogeneous bond amount (1,3 bond) of 0.20 mol % or more and 0.50 mol % or less. The branched polypropylene-based polymer according to claim 1 or 2, further having the following property (7):
Property (7): In an elution curve obtained by temperature rising elution fractionation (TREF) measurement using o-dichlorobenzene (ODCB), the content of components eluted at a temperature of 40° C. or less is 0.1% by weight or more and 3.0% by weight or less. The branched polypropylene polymer according to any one of claims 1 to 3, further having the following property (8):
Property (8): The melting point (Tm) measured by differential scanning calorimetry (DSC) is 145° C. or higher and 157° C. or lower. The branched polypropylene-based polymer according to any one of claims 1 to 4, further having the following property (9):
Property (9): The crystallization temperature (Tc) measured by differential scanning calorimetry (DSC) is 113° C. or higher and 118° C. or lower, and the melting point (Tm) and crystallization temperature (Tc) measured by differential scanning calorimetry (DSC) satisfy the following formula (2).
37<Tm-Tc≦0.907×Tm-99.64 (2)