JP7259707B2 - Branched propylene polymer - Google Patents

Description

The present invention relates to branched propylene-based polymers. More specifically, it relates to a branched propylene-based polymer that achieves both a nano-sized fiber diameter and a highly uniform fiber diameter.

Polypropylene is characterized by its low density and excellent chemical resistance. It is also highly recyclable and does not generate toxic gases when incinerated.
In recent years, many studies have been conducted to introduce a branched structure into polypropylene to improve suitability for sheet molding, blow molding, thermoforming, foam molding, melt spinning, etc., which require materials with relatively high melt tension. In addition, application to injection molding, injection foam molding, their modifiers, and textiles is underway.

In the field of products such as filters and masks, which require high dust collecting properties, high filterability, and texture, fibers with a small fiber diameter are required.
Therefore, Patent Document 1, Patent Document 2, and the like propose a method of reducing the fiber diameter by a meltblown method. In Patent Document 1, a fiber diameter of about 1 μm can be obtained, but the uniformity of the fiber diameter is insufficient. Moreover, it cannot be said that the fibers in Patent Document 2 are sufficiently thin.
In addition, Patent Document 3 proposes meltblown polypropylene particles that suppress smoke generation by reducing low molecular weight components using a metallocene catalyst, but the fiber diameter obtained here is sufficiently thin. do not have.

Thus, the actual situation is that a polypropylene fiber having a nano-sized fiber diameter and high uniformity has not yet been realized.

In addition, Patent Document 4 proposes a method of mixing a polyolefin resin with low crystallinity and a polyolefin resin with a long-chain branched structure as a method of improving texture, other than the method of reducing the fiber diameter.
However, since the resin obtained in this way is used in combination with a polypropylene-based resin having low crystallinity, although the texture is improved, the fibers are fused to each other, and there is a concern that the apparent fiber diameter will increase. There is a possibility that the fiber diameter will become non-uniform, and it has not been achieved from the viewpoint of compatibility between the nano-sized fiber diameter and the uniformity of the fiber diameter. As a result, high dust collection and high filterability cannot be achieved satisfactorily.
Furthermore, it is not mentioned that the melt-blown fibers obtained by the method of Patent Document 4 can produce fibers having a nano-sized fiber diameter and high uniformity with good productivity.

Also, as a method for obtaining nano-sized fiber diameters, there is known a solution-type electrospinning method (Patent Document 5) in which a resin is dissolved in a solvent and electrospun, but the used solvent must be recovered after molding. However, the manufacturing efficiency is poor. Moreover, it is not adapted by dissolving a polypropylene resin.

Therefore, a melt electrospinning method (Patent Document 6) has been developed in which a resin is melted by heat without using a solvent and electrostatically spun, but in order to lower the melt viscosity, the weight average molecular weight must be 40,000 or less. However, there is a concern that the molecular weight becomes too low to allow granulation, which makes handling difficult, and that smoking occurs during molding due to the low molecular weight.

JP-A-6-25958 Japanese Unexamined Patent Application Publication No. 2002-201560 JP 2007-145914 A JP 2017-222972 A JP 2005-264374 A JP 2013-64203 A

As described above, conventionally, fibers having a nano-sized fiber diameter and high uniformity have not been obtained with good productivity.
Accordingly, an object of the present invention is to provide a propylene-based polymer that achieves both a nano-sized fiber diameter and a high uniformity in fiber diameter, is resistant to thread breakage, and is easy to mold.

As a result of intensive studies, the present inventors have found that a branched propylene-based polymer has a branched propylene structure different from conventional ones, particularly a molecular weight distribution and branching distribution, and a complex viscosity coefficient η in dynamic viscoelasticity measurement. ^* By satisfying a specific formula for the angular frequency ω dependence of (ω) and the MFR, it was found that both the nano-sized fiber diameter and the high uniformity of the fiber diameter can be achieved, and the yarn is less likely to break and can be easily molded. .

The branched propylene-based polymer of the present invention has the following properties (1) to (4).
A branched propylene-based polymer having the following properties (1) to (4).
Characteristic (1): The melt flow rate (MFR) measured at a temperature of 230° C. and a load of 2.16 kg is greater than 100 g/10 minutes and not more than 1000 g/10 minutes.
Characteristic (2): The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by gel permeation chromatography (GPC) is 2.0 or more and 4.0 or less, and The ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) is 1.5 or more and 4.0 or less.
Characteristic (3): In the molecular weight distribution curve obtained by 3D-GPC, the branching index g' (Mz _abs ) at the absolute z-average molecular weight Mz _abs is 0.70 or more and 0.95 or less.
Characteristic (4): The angular frequency ω dependence of complex viscosity η ^* (ω) in dynamic viscoelasticity measurement and MFR satisfy the following relational expression (1).
log[η ^* (0.1rad/s)/η ^* (100rad/s)]≧−0.19×log(MFR)+0.58 Equation (1)
(Here, η ^* (0.1 rad/s) is the complex viscosity at ω=0.1 rad/s, and η ^* (100 rad/s) is the complex viscosity at ω=100 rad/s.)

It is preferable that the branched propylene-based polymer of the present invention further has the following property (5) from the viewpoint of achieving both a nano-sized fiber diameter and a high uniformity of the fiber diameter.
Characteristic (5): In the integral molecular weight distribution curve obtained by GPC, the ratio (W _1M ) of components having a molecular weight of 1,000,000 or more is 0.10% by mass or less.

It is preferable that the branched propylene-based polymer of the present invention further has the following property (6) from the viewpoint of resistance to thread breakage.
Characteristic (6): Melting point (Tm) measured with a differential scanning calorimeter (DSC) is 145° C. or higher.

It is preferable that the branched propylene-based polymer of the present invention further has the following property (7) in terms of the feel and texture of the product.
Characteristic (7): The mesopentad fraction (mmmm) of 5 chains of propylene units measured by ¹³ C-NMR is 93% or more.

The branched propylene-based polymer of the present invention may be degraded with an organic peroxide.

According to the present invention, it is possible to provide a propylene-based polymer that achieves both a nano-sized fiber diameter and a high uniformity in fiber diameter, is resistant to thread breakage, and is easy to mold.

FIG. 1 is a diagram for explaining baselines and intervals of a chromatogram in GPC. FIG. 2 shows the angular frequency ω of the sinusoidal strain on the horizontal axis, the measured G′(ω) and G″(ω) on the first vertical axis, and η ^* (ω) on the second vertical axis. It is an example of a graph taken and plotted. FIG. 3 shows the ratio [η ^* (0.1 rad/s)/η ^* (100 rad/s) of the complex viscosity on the low frequency side and the complex viscosity on the high frequency side of the propylene-based polymers of Examples and Comparative Examples. ] and MFR (unit: g/10 minutes). FIG. 4 is a diagram showing an example of a molecular weight distribution curve and an integral molecular weight distribution curve.

The branched propylene-based polymer of the present invention has the following properties (1) to (4).
Characteristic (1): The melt flow rate (MFR) measured at a temperature of 230° C. and a load of 2.16 kg is greater than 100 g/10 minutes and not more than 1000 g/10 minutes.
Characteristic (2): The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by gel permeation chromatography (GPC) is 2.0 or more and 4.0 or less, and The ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) is 1.5 or more and 4.0 or less.
Characteristic (3): In the molecular weight distribution curve obtained by 3D-GPC, the branching index g' (Mz _abs ) at the z-average molecular weight Mz _abs is 0.70 or more and 0.95 or less.
Characteristic (4): The angular frequency ω dependence of complex viscosity η ^* (ω) in dynamic viscoelasticity measurement and MFR satisfy the following relational expression (1).
log[η ^* (0.1rad/s)/η ^* (100rad/s)]≧−0.19×log(MFR)+0.58 Equation (1)
(Here, η ^* (0.1 rad/s) is the complex viscosity at ω=0.1 rad/s, and η ^* (100 rad/s) is the complex viscosity at ω=100 rad/s.)

The branched propylene-based polymer of the present invention has the properties (1) to (4) described above, and has a structure different from conventional branched propylene, particularly molecular weight distribution and branching distribution, and complex viscosity in dynamic viscoelasticity measurement. By satisfying a specific formula for the angular frequency ω dependence of the rate η ^* (ω) and the MFR, it is possible to achieve both a nano-sized fiber diameter and a high uniformity of the fiber diameter, and it is difficult to break the yarn and easy to mold. It is a propylene polymer.
The branched propylene-based polymer of the present invention has a specific MFR, and Mw/Mn, which is an index representing the spread of the molecular weight distribution, and Mz/Mw, which represents the spread of the high molecular weight side compared to Mw/Mn. and has a specific molecular weight distribution, and the branching index in the z-average molecular weight on the high molecular weight side is within a specific range. The branched propylene-based polymer of the present invention has a specific molecular weight distribution and an appropriate amount of branched structure in the polymer region, thereby having a specific long-term relaxation component. For example, when meltblown molding is performed, yarn breakage is less likely to occur even if the air flow rate is increased until the fiber diameter is reduced to nano-size. In addition, by making the angular frequency ω dependence of the complex viscosity η ^* (ω) and the MFR satisfy a specific formula, the molten molded body is subjected to elongation stress at an air flow rate maximized in terms of fluidity. It is presumed that by being able to follow, it is possible to achieve both nano-sized fiber diameter and high uniformity of fiber diameter, and to perform molding that is less likely to break.

The physical properties, production method, and the like of the branched propylene-based polymer of the present invention will be described below in detail for each item. Also, in this specification, the term "to" indicating a numerical range is used to include the numerical values before and after it as lower and upper limits.

I. Physical properties of branched propylene-based polymer (1):
The branched propylene-based polymer of the present invention has a melt flow rate (MFR) of more than 100 g/10 minutes and not more than 1000 g/10 minutes measured at a temperature of 230° C. and a load of 2.16 kg.
MFR is an index showing melt fluidity, and this value decreases as the molecular weight of the polymer increases. On the other hand, the smaller the molecular weight, the larger this value.
If the MFR is too small, the melt fluidity will be poor and heat molding will be difficult. Therefore, the MFR is greater than 100 g/10 min, preferably 120 g/10 min or greater, more preferably 250 g/10 min or greater.
On the other hand, if the MFR is too large, it causes a decrease in melt strength. Therefore, the MFR is 1000 g/10 min or less, preferably 500 g/10 min or less, more preferably 400 g/10 min or less.
In the present invention, the melt flow rate (MFR) is determined according to JIS K7210 "Plastics - Test method for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics", test conditions: 230 ° C. , are values measured with a load of 2.16 kgf.
The melt flow rate (MFR) can be easily adjusted by changing the temperature and pressure of polymerization or, as a general technique, by adding a chain transfer agent such as hydrogen during polymerization.
Melt flow rate (MFR) can also be adjusted by appropriately degrading higher molecular weight polymers.

Property (2):
4. The branched propylene-based polymer of the present invention has a weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Mw/Mn) of 2.0 or more, as measured by gel permeation chromatography (GPC). 0 or less, and the ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) is 1.5 or more and 4.0 or less.
Mw/Mn is an index representing the spread of the molecular weight distribution, and the larger this value, the wider the molecular weight distribution. If the Mw/Mn ratio is too small, the low molecular weight components will decrease and the melt fluidity will deteriorate. Therefore, Mw/Mn is 2.0 or more, preferably 2.1 or more, more preferably 2.2 or more. On the other hand, if Mw/Mn is too large, the amount of high-molecular-weight components will relatively increase, resulting in poor melt fluidity. Therefore, Mw/Mn is 4.0 or less, preferably 3.0 or less, more preferably 2.5 or less.
Similarly, Mz/Mw is an index representing the spread of the molecular weight distribution, and is an index showing the spread on the high molecular weight side compared to Mw/Mn. The larger these values are, the wider the molecular weight distribution is toward the high molecular weight side. If the Mz/Mw is too small, the high molecular weight component will decrease and the melt strength will decrease. Therefore, Mz/Mw is 1.5 or more, preferably 1.6 or more, more preferably 1.7 or more. On the other hand, if Mz/Mw is too large, the amount of high molecular weight components will relatively increase, resulting in poor melt fluidity. Therefore, Mz/Mw is 4.0 or less, preferably 3.5 or less, more preferably 3.0 or less, and even more preferably 2.0 or less.
The average molecular weight and molecular weight distribution (Mz, Mw, Mn, Mw/Mn, Mz/Mw) measured by GPC of branched propylene-based polymers vary depending on the temperature and pressure conditions of the propylene polymerization, or the most common As a method, it can be easily adjusted by adding a chain transfer agent such as hydrogen during the polymerization of propylene. Furthermore, when using two or more types of metallocene complexes, the amount can be controlled by changing the amount ratio thereof.
The average molecular weight and molecular weight distribution can also be adjusted by appropriately degrading the higher molecular weight polymer.

The branched propylene-based polymer of the present invention preferably has an Mw of 70,000 or more and 130,000 or less from the viewpoint of the balance between melt fluidity and melt strength. Mw is preferably 70,000 or more, more preferably 80,000 or more from the viewpoint of melt strength, and preferably 130,000 or less from the viewpoint of melt fluidity.

Mz, Mw, Mn, Mw / Mn, Mz / Mw defined above, and the values of W _1M described later are all obtained by gel permeation chromatography (GPC), and the measurement method, The details of the measuring 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
Sample preparation is performed by using the sample and ODCB (containing 0.5 mg/mL dibutylhydroxytoluene (BHT)) to prepare a 1 mg/mL solution and dissolving it at 140°C for about 1 hour. .
In addition, the baseline and interval of the obtained chromatogram are performed as shown in FIG.
Further, conversion from the retention volume obtained by GPC measurement to molecular weight is performed using a previously prepared standard polystyrene calibration curve. The standard polystyrene used is the following brand manufactured by Tosoh Corporation.
Brand: F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is generated by injecting 0.2 mL of a solution dissolved in ODCB (containing 0.5 mg/mL of BHT) at 0.5 mg/mL each. A calibration curve uses a cubic equation obtained by approximation using the least squares method.
Viscosity formula used for conversion to molecular weight: [η]=K×M ^α uses the following numerical values.
PS: K=1.38×10 ⁻⁴ , α=0.7
PP: K=1.03×10 ⁻⁴ , α=0.78

Property (3): branching index g' (Mz _abs ) measured by 3D-GPC
The branched propylene-based polymer of the present invention has a branching index g' (Mz _abs ) at an absolute z-average molecular weight Mz _abs of 0.70 or more and 0.95 or less in a molecular weight distribution curve obtained by 3D-GPC.
The branched propylene-based polymer of the present invention has a branching index g′ (Mz _abs ) in the absolute z-average molecular weight Mz _abs within the above range, so that the melt strength as a whole, especially the elongational viscosity and the melt fluidity are well balanced. can keep.
When the branching index g′ (Mz _abs ) in Mz _abs is 0.95 or less, the branching of the high-molecular-weight component exists to some extent or more, and it is presumed that the melt strength is improved. On the other hand, the branching index g'(Mz _abs ) is When it is 0.70 or more, the branching of the high-molecular-weight component is not excessive, so it is presumed that the balance with the melt fluidity will be good.
The branched propylene-based polymer of the present invention preferably has a branching index g′ (Mz _abs ) in Mz _abs of 0.76 or more, more preferably 0.77 or more, from the viewpoint of melt strength. is preferred, on the other hand, it is preferably 0.93 or less, and more preferably 0.90 or less.

Property (3'):
In addition, the branched polypropylene polymer of the present invention, in the molecular weight distribution curve obtained by 3D-GPC,
There is a relationship of M _abs pt<Mw _abs <Mz _abs <1,000,000,
Branching index g' (M _abs pt) at M _abs pt is preferably 0.95 or more and 1.00 or less Branching index g' (Mw _abs ) at Mw _abs is preferably 0.90 or more and 1.00 or less.
Here, M _abs pt, Mw _abs and Mz _abs represent the absolute molecular weight, weight average molecular weight and z average molecular weight corresponding to the peak positions, respectively.
The branched polypropylene-based polymer of the present invention preferably has a branch distribution within the above range because it can maintain the melt strength as a whole, especially the balance between elongational viscosity and melt fluidity.

Here, the M _abs pt, which corresponds to the molecular weight of the largest component, is considered to be easily correlated with fluidity under high stress. When the M _abs pt is less than the Mw _abs , it is presumed that the melt fluidity is improved. Moreover, the Mz _abs is considered to be correlated with how high the molecular weight of the component is, and it is presumed that the Mz _abs of less than 1,000,000 improves the melt fluidity.

The branched polypropylene polymer of the present invention preferably has a branching index g' (M _abs pt) in M _abs pt of 0.95 or more and 1.00 or less in the molecular weight distribution curve obtained by 3D-GPC. . Since the branching index g′ (M _abs pt) in the above M _abs pt is 1.00 or close to 1.00, the most abundant component indicates no or few branched components. It is presumed that in the case of the largest number of components, the melt fluidity is improved because there are no or few branched components.
Among them, the branched polypropylene polymer of the present invention preferably has a branching index g' (M _abs pt) of 0.95 or more in the M _abs pt from the viewpoint of fluidity under high stress, and furthermore, 0 0.98 or higher is preferred.

The branched polypropylene polymer of the present invention preferably has a branching index g' (Mw _abs ) in Mw _abs of 0.90 or more and 1.00 or less in the molecular weight distribution curve obtained by 3D-GPC. The branching index g′ (Mw _abs ) at the weight average molecular weight Mw _abs is also 1.00 or close to 1.00, indicating that the component at the weight average molecular weight is also free or low in branched components. As for the components in the weight-average molecular weight, it is presumed that the melt fluidity is improved when there are no or few branched components.
From the point of achieving a good balance between melt fluidity and elongational viscosity, it is preferable that the component at the weight average molecular weight Mw _abs having a higher molecular weight than the M _abs pt component corresponding to the largest component has more branches, that is, the branch Preferably, the index g' (M _abs pt)>branching index g' (Mw _abs ).
Among them, the branched polypropylene polymer of the present invention preferably has a branching index g' (Mw _abs ) in the Mw _abs of 0.93 or more from the viewpoint of fluidity under high stress.
Further, it is preferably 0.95 or more, while it is preferably less than 1.00, and more preferably 0.98 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 branched structure and [η] _lin of a linear polymer with the same molecular weight. and takes values less than 1.0 in the presence of long-chain branched structures.
Definitions are described, for example, in "Developments in Polymer Characterization-4" (JV Dawkins ed. Applied Science Publishers, 1984) and are guidelines 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 scatterometer and a viscometer as detectors as described below.
As used herein, 3D-GPC refers to a GPC apparatus to which three detectors are connected. Three such detectors are a differential refractometer (RI), a viscosity detector (Viscometer) and a multi-angle laser light scattering detector (MALLS).
As a GPC apparatus equipped with a differential refractometer (RI) and a viscosity detector (Viscometer), Alliance GPCV2000 manufactured by Waters is used. As a light scattering detector, a multi-angle laser light scattering detector (MALLS) DAWN-E manufactured by Wyatt Technology is used.
The detectors are connected in the order MALLS, RI, Viscometer.
The mobile phase solvent is 1,2,4-trichlorobenzene (antioxidant Irganox 1076 manufactured by BASF Japan Co., Ltd. added at a concentration of 0.5 mg/mL).
The flow rate is 1 mL/min, and two Tosoh GMHHR-H(S)HT columns connected in series are used.
The temperature of the column, sample injection part and each detector is 140°C.
The sample concentration is 1 mg/mL and the injection volume (sample loop volume) is 0.2175 mL.
In determining the absolute molecular weight (M _abs ), the root-mean-square radius of gyration (Rg), and the intrinsic viscosity ([η]) obtained from the Viscometer, the data processing software ASTRA (version 4.73.04) attached to MALLS was used. Use it and calculate with reference to the following literature.
References:
1. Developments in Polymer Characterization, vol. 4. Essex: Applied Science; Chapter1.
2. Polymer, 45, 6495-6505 (2004)
3. Macromolecules, 33, 2424-2436 (2000)
4. Macromolecules, 33, 6945-6952 (2000)
The branching index _g ' is the _ratio ([ η] _br /[η] _lin ).

The introduction of long-chain branched structures into polymer molecules reduces the radius of gyration compared to linear polymer molecules of the same molecular weight. Since the intrinsic viscosity decreases as the radius of gyration decreases, the intrinsic viscosity of the _branched polymer ([η] _br ) ratio ([η] _br /[η] _lin ) becomes smaller. Therefore, a polymer having a long-chain branched structure has a branching index g′([η] _br /[η] _lin ) of less than 1.0, and a linear polymer, by definition, has a branching index g′ of 1. .0.
Here, [η] _lin is obtained using a commercially available homopolypropylene (Novatec PP (registered trademark) grade name: FY6, manufactured by Nippon Polypropylene Co., Ltd.) as a linear polymer. It is known as the _Mark -Houwink-Sakurada formula that the logarithm of [η] _lin of a linear polymer has a linear relationship with the logarithm of the molecular weight. A numerical value can be obtained by extrapolation.
A branching index g′ of less than 1.0 can be achieved by introducing many long-chain branches, and can be achieved by controlling the selection of catalysts, their combinations and ratios, and prepolymerization conditions. Become.
In order to keep the branching index g' within the above specific range, it is possible to appropriately adjust the amount of hydrogen during polymerization in addition to the selection, combination and amount ratio of catalysts, as will be described later.
The branching index g' can also be adjusted by appropriately degrading a polymer having a higher molecular weight long-chain branched structure.

Property (4):
The branched propylene-based polymer of the present invention satisfies the following relational expression (1) between the angular frequency ω dependence of the complex viscosity η ^* (ω) in dynamic viscoelasticity measurement and the MFR.
log[η ^* (0.1rad/s)/η ^* (100rad/s)]≧−0.19×log(MFR)+0.58 Equation (1)
(Here, η ^* (0.1 rad/s) is the complex viscosity at ω=0.1 rad/s, and η ^* (100 rad/s) is the complex viscosity at ω=100 rad/s.)

Polymer melts generally exhibit non-Newtonian properties, and the non-Newtonian properties can be evaluated by measuring dynamic viscoelasticity. Dynamic viscoelasticity measurements are made in the melt and measure strain and stress, commonly referred to as the gap loading method. As for the gap, since polymer melts are generally treated as viscoelastic bodies, parallel discs are used for measurement.
In this viscoelastic phenomenology, we consider the case where two parallel discs are filled with a high-viscosity polymer melt and are displaced (shear strain). At time: t=0, after applying a constant strain: γ= _γ0 , the stress G(t) that maintains this constant amount of strain decreases exponentially with time. This time indicates the speed at which the stress in the polymer melt relaxes, is called relaxation time, and indicates a value specific to the substance. The ratio of the relaxing stress σ(t) to the initially applied constant strain γ ₀ varies with time. Elastic modulus G(t)=σ(t)/γ ₀ is called the relaxation elastic modulus.
If the constant strain is sinusoidally oscillating at an angular frequency ω, then the elastic modulus G ^* (ω), which is defined as the ratio of sinusoidal strain to stress, becomes a complex number and is expressed by the following equation as the complex elastic modulus.
G ^* (ω)=G′(ω)+iG″(ω)
The real part is called the storage elastic modulus G', and the imaginary part is called the loss elastic modulus G''. , which means that the stress has the same frequency, but the phase changes. Tan I'm in.
Also, the complex viscosity η ^* is similarly expressed by the following equation as a complex number and its absolute value using the storage elastic modulus G′, the loss elastic modulus G″, and the angular frequency ω.

正弦的ひずみの角周波数ωを横軸に取り、第一縦軸に測定したＧ’（ω）とＧ”（ω）、第二縦軸にη^＊（ω）を縦軸に取り、プロットしたグラフの一例を図２に示す。

The angular frequency ω of the sinusoidal strain is plotted on the horizontal axis, the measured G′(ω) and G″(ω) on the first vertical axis, and η ^* (ω) on the second vertical axis. An example of the graph is shown in FIG.

The fact that the branched propylene-based polymer of the present invention satisfies the above relational expression (1) means that the branched propylene-based polymer of the present invention has a complex viscosity coefficient on the low frequency side and a complex viscosity on the high frequency side. It shows that the viscosity ratio [η ^* (0.1 rad/s)/η ^* (100 rad/s)] is larger than a specific relational expression in terms of fluidity.
Generally, in the non-Newtonian properties of polymer melts, the presence of a long-term relaxation component increases the storage modulus and loss modulus on the low frequency side. The complex viscosity increases as the storage modulus and loss modulus increase. By using the complex viscosity, both the storage elastic modulus and the loss elastic modulus are reflected, and it is presumed that this is an index representing properties suitable for ultrafine fiber molding.
Since the branched propylene-based polymer of the present invention has an appropriate amount of branched structure in the high molecular weight region, it has an appropriate amount of long-term relaxation component. η ^* (0.1 rad/s)/η ^* (100 rad/s)] is greater in terms of fluidity than conventional propylene-based polymers, and satisfies the relational expression (1).
If the complex viscosity on the low frequency side is large in terms of fluidity, for example, when fiber molding is performed, the air flow rate can be increased. Since it can follow, even if it is made finer, the fiber diameter tends to be uniform and the yarn breakage is less likely to occur.

The branched propylene-based polymer of the present invention more preferably satisfies the following relational expression (1′), and even more preferably satisfies the following relational expression (1″).
log[η ^* (0.1rad/s)/η ^* (100rad/s)]≧−0.19×log(MFR)+0.59 Expression (1′)
log[η ^* (0.1rad/s)/η ^* (100rad/s)]≧−0.19×log(MFR)+0.60 Formula (1″)

In general, there is a problem that if the fluidity is increased, the melt strength is lowered and becomes insufficient. Therefore, it is desired that the propylene-based polymer has both the required fluidity and excellent melt strength. Formulas (1), (1′), and (1″) above show that the branched propylene-based polymer has higher fluidity than conventional propylene-based polymers on the low frequency side in terms of fluidity. The complex viscosity of the branched propylene-based polymer of the present invention is large, indicating a balance between fluidity and melt strength. η ^* (0.1 rad / s) / η ^* (100 rad / s)] is considered to be a function that has a negative correlation with the increase in fluidity (MFR), the parameters of the function are set, and in the present invention It shows that the complex viscosity ratio of the propylene-based polymer to be produced is greater than the complex viscosity ratio defined by the function in terms of fluidity.Specifically, based on the data of Examples and Comparative Examples, Assuming values of the complex viscosity ratio and the fluidity (MFR) that distinguish the example from the comparative example of the prior art, the relational expression that holds between the complex viscosity ratio and the fluidity (MFR): , the parameters of the relational expression are determined by the method of least squares (see FIG. 3).

On the other hand, for example, in the case of ultrafine fiber molding such as meltblown where the stretching stress is high at the tip of the nozzle, if the complex viscosity on the low frequency side is too high, the molten resin is difficult to stretch at the tip of the nozzle in the initial stage of molding. There is a risk that the thread will break easily.
Therefore, the branched propylene-based polymer of the present invention preferably further satisfies the following relational expression (1′″).
log [η ^* (0.1 rad/s)/η ^* (100 rad/s)] ≤ -0.19 x log (MFR) + 0.73 Formula (1'")

Property (4'):
Further, in the branched propylene-based polymer of the present invention, it is preferable that the angular frequency ω dependence of the complex elastic modulus G′(ω) in dynamic viscoelasticity measurement and the MFR satisfy the following relational expression (2): .
log [G' (0.1 rad/s) / G' (100 rad/s)] ≧ -0.73 × log (MFR) -2.39 formula (2)
(Here, G' (0.1 rad/s) is the storage modulus of ω = 0.1 rad/s, and G' (100 rad/s) is the storage modulus of ω = 100 rad/s.)

That is, the ratio of the storage elastic modulus on the low frequency side to the storage elastic modulus on the high frequency side [G' (0.1 rad/s) / G' (100 rad/s)] is larger than a specific relational expression in terms of MFR. is preferred.
In general, in non-Newtonian properties exhibited by polymer melts, the storage modulus on the low frequency side increases as the long-term relaxation component increases. Since the branched propylene-based polymer of the present invention has an appropriate amount of branched structure in the high molecular weight region, it has an appropriate amount of long-term relaxation component, so the storage elastic modulus on the low frequency side increases, and the storage elastic modulus ratio [G '(0.1 rad/s)/G'(100 rad/s)] is greater in terms of fluidity than conventional propylene-based polymers, and can satisfy the following relational expression (2).
If the storage elastic modulus on the low frequency side is high, for example, when fiber molding is performed, the melted molded body can follow the elongation stress, so that even if the fiber is finely divided, the fiber is less likely to break.
The branched propylene-based polymer of the present invention preferably further satisfies the following relational expression (2′), and more preferably satisfies the following relational expression (2″).
log [G' (0.1 rad/s) / G' (100 rad/s)] ≧ -0.73 × log (MFR) -2.38 formula (2')
log [G' (0.1 rad/s) / G' (100 rad/s)] ≧ -0.73 × log (MFR) -2.37 Formula (2")
satisfies the relational expression of

On the other hand, for example, in the case of ultrafine fiber molding such as meltblown where the stretching stress is high at the tip of the nozzle, if the storage modulus on the low frequency side is too high, the molten resin is stretched at the tip of the nozzle in the initial stage of molding. It may become difficult and the thread may break easily.
Therefore, the branched propylene-based polymer of the present invention preferably further satisfies the following relational expression (2''').
log [G' (0.1 rad/s) / G' (100 rad/s)] ≤ -0.73 × log (MFR) -2.09 Formula (2'")

The dynamic viscoelasticity of the branched propylene-based polymer of the present invention can be measured with a usual device for measuring dynamic viscoelasticity. Devices for measuring dynamic viscoelasticity include, for example, ARES-G2 manufactured by TA Instruments.
The propylene-based polymer is compression-molded with a press at 180° C. for 5 minutes so as not to introduce air bubbles into a disk-shaped measurement sample having a thickness of 2.0 mm and a diameter of 25 mm. Sample measurement is performed by using parallel discs with a diameter of 25 mm that are kept at 180° C. After compressing the sample for measurement with a thickness of 2.0 mm to a thickness of 1.5 mm, place it with a gap of 1.5 mm. At 180° C., with a strain of anywhere from 0.1% to 40%, and in the frequency range from 0.01 rad/sec to 100 rad/sec, using parallel discs with a diameter of 25 mm, The storage elastic modulus (G') and the loss elastic modulus (G'') are measured at 5 points per one digit of ω.

In order to satisfy the above formula (1), it has a specific molecular weight distribution and is achieved by introducing an appropriate amount of long chain branches. It is possible by controlling the amount of hydrogen and the like for polymerization.
Moreover, in order to satisfy the above formula (1), adjustment can also be made by appropriately degrading a polymer having a higher molecular weight long-chain branched structure. In order to prepare a polymer having a long-chain branched structure with a higher molecular weight, for example, in a method using a catalyst containing a plurality of metallocene complexes, one of the metallocene complexes used is one that can produce a polymer with a high molecular weight. After selection, it can be easily adjusted by controlling the amount ratio to the other metallocene complex to be produced on the low molecular weight side, the amount of hydrogen added during polymerization, and the polymerization temperature.

Property (5):
In the branched propylene-based polymer of the present invention, the ratio (W _1M ) of components having a molecular weight of 1,000,000 or more is 0 with respect to 100% by mass of the total amount of the branched propylene-based polymer in the integrated molecular weight distribution curve obtained by GPC. 0.10% by mass or less is preferable from the point of uniformity in following elongation stress.
When the amount of the ultra-high molecular weight branched component increases, the melt strength becomes too high, and the elongational stress may not be followed uniformly. Therefore, the branched propylene-based polymer of the present invention preferably has a W _1M of 0.10% by mass or less, more preferably 0.05% by mass or less, and preferably 0.00% by mass.
In the present invention, W _1M is an integral molecular weight distribution curve obtained by GPC (the total weight is normalized to 1), and the integral value up to a molecular weight (M) of 1,000,000 (Log (M) = 6.0) is , multiplied by 100. An example of the integral molecular weight distribution curve is shown in FIG.
W _1M can be achieved, for example, by controlling prepolymerization conditions, the amount of hydrogen during polymerization, and the like, in addition to the selection, combination, and ratio of catalysts.
W _1M can also be adjusted by appropriately degrading a polymer having a higher molecular weight long-chain branched structure.

Property (6):
The branched propylene-based polymer of the present invention preferably has a melting point (Tm) of 145° C. or higher as measured by a differential scanning calorimeter (DSC) in terms of heat resistance of the product.
The branched propylene-based polymer has higher heat resistance as the product has a higher Tm. Therefore, 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 Tm of the branched propylene-based polymer is too high, the rigidity of the branched propylene-based polymer may become too high, resulting in poor touch and feel. Therefore, Tm is preferably 158° C. or lower, more preferably 157° C. or lower, and even more preferably 156° C. or lower.

Property (6'):
In addition, the branched propylene-based polymer of the present invention preferably has a crystallization temperature (Tc) of 105° C. or higher, more preferably 108° C. or higher, still more preferably 113° C. as measured by a differential scanning calorimeter (DSC). C. or higher, while it is preferably 125.degree. C. or lower, more preferably 122.degree. The above range is preferable as a range in which the product is solidified by crystallization during molding.

In the case of polypropylene, Tm and Tc can be controlled by controlling the crystal thickness, and the crystal thickness is proportional to the regularly inserted propylene chains. That is, Tm and Tc are lowered by the insertion of defects due to ethylene units and regioregularity. The branched propylene-based polymer of the present invention is prepared by selecting a complex that reduces defects due to regioregularity as a polymerization catalyst, selecting a combination of multiple complexes, and controlling the polymerization temperature, pressure conditions, and crystal thickness. , Tm can be controlled.

In the present invention, Tm is determined by using a DSC (DSC6200) manufactured by Seiko Instruments Inc., packing 5 mg of a sheet-shaped sample piece in an aluminum pan, heating from room temperature to 200 ° C. at a heating rate of 100 ° C./min, and heating for 5 minutes. After holding, the temperature is lowered to 40°C at a temperature drop rate of 10°C/min, and the crystal maximum peak temperature (°C) when crystallized is obtained as the crystallization temperature (Tc). The maximum melting peak temperature (°C) when the temperature is raised at 1/min can be obtained as the melting point (Tm).
The sheet-like sample was obtained by sandwiching the branched propylene-based polymer powder between press plates, preheating at 190°C for 2 minutes, pressing at 5 MPa for 2 minutes, and then cooling at 0°C and 10 MPa for 2 minutes. ,Obtainable.

Property (7):
The branched propylene-based polymer of the present invention has a mesopentad fraction (mmmm) of 5 chains of propylene units measured by ¹³ C-NMR of 93% or more, which improves the balance between melt fluidity and elongational viscosity. preferred from

( ¹³ C-NMR measurement method)
[Sample preparation and measurement conditions]
200 mg of a sample was mixed with 2.4 mL of o-dichlorobenzene/deuterobrominated benzene (C ₆ D ₅ Br) = 4/1 (volume ratio) and hexamethyldisiloxane, which is a reference substance for chemical shift, and an NMR sample with an inner diameter of 10 mmφ. Put into a tube and melt uniformly with a block heater at 150°C.
NMR measurement is performed using a Bruker Biospin AV400 type NMR apparatus equipped with a 10 mmφ cryoprobe.
The measurement conditions for ¹³ C-NMR are a sample temperature of 120° C., a pulse angle of 90°, a pulse interval of 15 seconds, and an integration count of 1024 times, and the broadband decoupling method is used.
The chemical shifts are set to 1.98 ppm for the hexamethyldisiloxane ¹³ C signal and the chemical shifts for the other ¹³ C signals are referenced to this.
[Method for calculating mesopentad fraction (mmmm)]
The mesopentad fraction (mmmm) of 5 chains of propylene units is obtained 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 ) Equation (3)
Here, I _mm represents the integrated intensity of the ¹³ C signal attributed to the bonding mode of the propylene unit triplet in mm, and the integrated intensity of the ¹³ C signal with a chemical shift in the range of 23.6 to 21.1 ppm (hereinafter " I _23.6-21.1 ”).
I _mrrm represents the integrated intensity of the ¹³ C signal attributed to the bonding mode of mrrm for 5 chains of propylene units, and is a value indicated by I _{19.9 to 19.7} .
Spectral attribution can be performed with reference to Polymer Journal, Vol. 16, p. 717 (1984), Asakura Shoten, 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, etc., but the regions are easy to identify.

II. Method for Producing Branched Propylene-Based Polymer As for the method for producing the branched propylene-based polymer of the present invention, any method can be used as long as it is a method for obtaining a branched propylene-based polymer that satisfies the above-described physical properties that characterize the present invention. Well, there are no particular restrictions. Examples thereof include a macromer copolymerization method using a metallocene catalyst, preferably a method using a catalyst containing a plurality of metallocene compounds as described below, which yields a long-chain branched propylene-based polymer.
As a method for producing the branched propylene-based polymer of the present invention, among others, a method for producing a branched propylene-based polymer using the following catalyst components (A), (B) and (C) as catalysts for propylene polymerization. are preferred.
(A): At least one kind from component [A-1], which is a compound represented by the following general formula (a1), and at least one kind from [A-2], which is a compound represented by general formula (a2) selected, two or more transition metal compounds of Group 4 of the periodic table Component [A-1]: Compound represented by general formula (a1) Component [A-2]: Compound represented by general formula (a2) (B): compound or ion-exchange layered silicate that reacts with component (A) to form an ion pair (C): organoaluminum compound

The branched propylene-based polymer of the present invention may be polymerized using the catalyst components (A), (B) and (C) as catalysts for propylene polymerization. Alternatively, the branched propylene-based polymer of the present invention can be obtained by using the catalyst components (A), (B) and (C) as a catalyst for propylene polymerization to produce a branched propylene-based polymer having a higher molecular weight than the branched propylene-based polymer of the present invention. It may be produced by polymerizing a propylene-based polymer and degrading the high molecular weight branched propylene-based polymer.
In the method for producing the branched propylene-based polymer of the present invention, among others, the catalyst components (A), (B) and (C) are used as catalysts for propylene polymerization because they can be produced stably on an industrial scale with good productivity. ) to produce a branched propylene-based polymer (Z) having the following properties (i) to (ii); and reducing the branched propylene-based polymer (Z) with an organic peroxide. It is preferable to have a step of forming.
Characteristic (i) MFR is 1 g/10 minutes or more and 10 g/10 minutes or less.
Characteristic (ii) In the molecular weight distribution curve obtained by 3D-GPC, the branching index g'(1M) at an absolute molecular weight M _abs of 1,000,000 is 0.70 or more and 0.95 or less.

The branched propylene-based polymer (Z) to be degraded has a characteristic (i) MFR of 0.1 g/10 min or more and 10 g/10 min or less. It is preferable from the viewpoint of making the MFR of the polymer greater than 100 g/10 minutes and 1000 g/10 minutes or less. The MFR of the branched propylene-based polymer (Z) is preferably 2 g/10 minutes or more, more preferably 5 g/10 minutes or more.
On the other hand, if the MFR of the branched propylene-based polymer (Z) is too high, less organic peroxide will be used during degradation, and there is a risk that the necessary high-molecular-weight branched components will not be cleaved. Therefore, the MFR of the branched propylene-based polymer (Z) is preferably 9 g/10 minutes or less, more preferably 8 g/10 minutes or less.
The MFR of the branched propylene-based polymer (Z) can also be measured in the same manner as described above. As a method, it can be easily adjusted by a method of adding a chain transfer agent such as hydrogen at the time of polymerization.

The branched propylene-based polymer (Z) to be degraded has a branching index g' (1M) of 0 at an absolute molecular weight M _abs of 1,000,000 in the characteristic (ii) molecular weight distribution curve obtained by 3D-GPC. .70 or more and 0.95 or less is preferable from the viewpoint that the branching index g' (Mz _abs ) in Mz _abs of the branched propylene-based polymer after degradation is 0.70 or more and 0.95 or less. .
The branched propylene-based polymer (Z) has a branching index g'(1M) at an absolute molecular weight M _abs of 1,000,000 that is more preferably 0.73 or more, more preferably 0.75 or more. Preferably, on the other hand, it is more preferably 0.90 or less, and even more preferably 0.88 or less.

In addition, the branched propylene-based polymer (Z) to be degraded has, in the characteristic (ii′) molecular weight distribution curve obtained by 3D-GPC,
There is a relationship of M _abs pt<Mw _abs <Mz _abs <1,000,000,
Branching index g' (M _abs pt) at M _abs pt is 0.90 or more and 1.00 or less Branching index g' (Mw _abs ) at Mw _abs is 0.85 or more and 0.95 or less Branching index g at Mz _abs '(Mz _abs ) is preferably 0.80 or more and 0.90 or less.
The fact that the branch distribution of the branched propylene-based polymer (Z) to be degraded is within the above range means that the branched propylene-based polymer obtained after degradation has a particularly good balance between elongational viscosity and melt fluidity. It is preferable from the point of keeping.
The branched propylene-based polymer (Z) to be degraded preferably has a branching index g' (M _abs pt) in the M _abs pt of 0.90 or more, more preferably 0.95 or more. This is particularly preferred from the viewpoint of fluidity under high stress of the branched propylene-based polymer obtained after degradation.
The branched propylene-based polymer (Z) to be degraded preferably has a branching index g′ (Mw _abs ) in the Mw _abs of 0.85 or more, more preferably 0.88 or more. On the other hand, it is preferably 0.95 or less, more preferably 0.93 or less, from the viewpoint of fluidity under high stress of the branched propylene-based polymer obtained after degradation.
The branched propylene-based polymer (Z) to be degraded preferably has a branching index g′ (Mz _abs ) in Mz _abs of 0.80 or more, more preferably 0.83 or more. On the other hand, it is preferably 0.90 or less, more preferably 0.88 or less, from the viewpoint of increasing the melt strength of the branched propylene-based polymer obtained after degradation.
The branching index g' of the branched propylene-based polymer (Z) can also be measured in the same manner as described above. In addition to the amount ratio, it is possible by appropriately adjusting the amount of hydrogen during polymerization.

The branched propylene-based polymer (Z) to be degraded has a molecular weight of 1,000,000 with respect to 100% by mass of the total branched propylene-based polymer in the characteristic (iii) integrated molecular weight distribution curve obtained by GPC. The ratio (W _1M ) of the above components is preferably 3.0% by mass or more, more preferably 4.0% by mass or more, and is 10.0% by mass or less, and further 9.0% by mass or less. is preferable because the branching index g' (Mz _abs ) in Mz _abs of the branched propylene-based polymer after degradation is 0.70 or more and 0.95 or less.
W _1M of the branched propylene-based polymer (Z) can also be measured _in the same manner as described above. As a general technique, it can be easily adjusted by adding a chain transfer agent such as hydrogen during polymerization.

The branched propylene-based polymer (Z) to be degraded has a ratio (Mw/Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) obtained by characteristic (iv) GPC. It is preferably 0 or more and 5.5 or less because the Mw/Mn of the branched propylene-based polymer after degradation is 2.0 or more and 4.0 or less.
Further, the ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) of the branched propylene-based polymer (Z) to be degraded is 3.0 or more; 0.5 or less is preferable in order to make the Mz/Mw of the branched propylene-based polymer after degradation 1.5 or more and 4.0 or less.
The Mw/Mn and Mz/Mw of the branched propylene-based polymer (Z) can also be measured in the same manner as described above, and the Mw/Mn and Mz/Mw of the branched propylene-based polymer (Z) are determined by the catalyst In addition to the selection, combination and amount ratio thereof, the polymerization temperature and pressure are changed, or as a general method, a method of adding a chain transfer agent such as hydrogen during polymerization can be easily adjusted. can.

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

[In general formula (a1), R ¹¹ and R ¹² each independently represent a heterocyclic group containing nitrogen, oxygen or sulfur and having 4 to 16 carbon atoms. R ¹³ and R ¹⁴ are each independently 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 from these, or represents 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 optionally having a hydrocarbon group having 1 to 20 carbon atoms, and M ¹¹ represents zirconium or hafnium. wherein X ¹¹ and Y ¹¹ are each independently 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 It represents a halogenated hydrocarbon group, 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, a substituted a substituted 2-furfuryl group, more preferably a substituted 2-furfuryl group.
When R ¹¹ and R ¹² are groups selected from nitrogen-, oxygen- or sulfur-containing heterocyclic groups having 4 to 16 carbon atoms, the terminal vinyl ratio (Rv) can be increased. By introducing a large substituent on the group, the coordination field on the heterocyclic ring and the transition metal is facilitated to take an appropriate positional relationship such that the methyl group of the growing polymer chain overlaps, thereby increasing the terminal vinyl ratio (Rv) can be made higher.
Further, substituted 2-furyl group, substituted 2-thienyl group and substituted 2-furfuryl group include alkyl groups having 1 to 6 carbon atoms such as methyl group, ethyl group and propyl group, Examples include halogen atoms such as fluorine and chlorine atoms, alkoxy groups having 1 to 6 carbon atoms such as methoxy and ethoxy groups, and trialkylsilyl groups. Among these, a methyl group and a trimethylsilyl group are preferred, and a methyl group is particularly preferred.
Furthermore, 5-methyl-2-furyl group is particularly preferred as R ¹¹ and R ¹² . Also, R ¹¹ and R ¹² are preferably the same as each other.

R ¹³ and R ¹⁴ are each independently 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 from these. , or a heterocyclic group having 4 to 16 carbon atoms containing nitrogen, oxygen or sulfur.
In particular, by increasing the bulk of R ¹³ and R ¹⁴ , it is possible to obtain a propylene polymer having high stereoregularity and regioregularity, and thus less defects during lamellar formation and a high terminal vinyl ratio.
Therefore, R ¹³ and R ¹⁴ each have one or more hydrocarbon groups having 1 to 6 carbon atoms or a hydrocarbon group having 1 to 6 carbon atoms on the aryl cyclic skeleton within the range of 6 to 16 carbon atoms. a silyl group having 1 to 6 carbon atoms, a halogen-containing hydrocarbon group having 1 to 6 carbon atoms, or an aryl group optionally having a halogen atom as a substituent, and specific examples of such R ¹³ and R ¹⁴ include 4-t -butylphenyl group, 2,3-dimethylphenyl group, 3,5-di-t-butylphenyl group, 4-chlorophenyl group, 4-trimethylsilylphenyl group, 1-naphthyl group and 2-naphthyl group.
Further, R ¹³ and R ¹⁴ more preferably have one or more hydrocarbon groups having 1 to 6 carbon atoms or hydrocarbon groups having 1 to 6 carbon atoms in the range of 6 to 16 carbon atoms. A silyl group, a halogen-containing hydrocarbon group having 1 to 6 carbon atoms, or a phenyl group having a halogen atom as a substituent. Moreover, the substituted position is preferably the 4-position on the phenyl group. Specific examples of such R ¹³ and R ¹⁴ are 4-t-butylphenyl, 4-biphenylyl, 4-chlorophenyl and 4-trimethylsilylphenyl groups. Also, it is preferable that R ¹³ and R ¹⁴ are the same.

X ¹¹ and Y ¹¹ above are ancillary ligands and react with component (B) to form an active metallocene capable of olefin polymerization. Therefore, the types of ligands of X ¹¹ and Y ¹¹ are not limited as long as this object is achieved, 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 of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, an oxygen-containing hydrocarbon group of 1 to 20 carbon atoms, an amino group or an alkylamino group of 1 to 20 carbon atoms represents

The above Q ¹¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms that binds two five-membered rings, or a silylene group or a germylene group optionally having a hydrocarbon group having 1 to 20 carbon atoms. show. When two hydrocarbon groups are present on the above-mentioned silylene group or germylene group, they may combine with each other to form a ring structure.
Specific examples of Q ¹¹ above include alkylene groups such as methylene, methylmethylene, dimethylmethylene and 1,2-ethylene; arylalkylene groups such as diphenylmethylene; silylene groups; methylsilylene, dimethylsilylene, diethylsilylene, di(n -propyl)silylene, di(i-propyl)silylene, di(cyclohexyl)silylene and other alkylsilylene groups; methyl(phenyl)silylene and other (alkyl)(aryl)silylene groups; diphenylsilylene and other arylsilylene groups; tetramethyl Alkyloligosilylene groups such as disilylene; germylene groups; alkylgermylene groups in which silicon in the above divalent hydrocarbon group having 1 to 20 carbon atoms is substituted with germanium; (alkyl)(aryl)germylene groups ; an arylgermylene group and the like can be mentioned. 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 preferable, and an alkylsilylene group and an alkylgermylene group are particularly preferable.

Among the compounds represented by the 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. can.

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,
is.

Also, it is particularly preferable to
(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,
is.

1-2. Component [A-2]
As the component [A-2], a metallocene compound represented by the following general formula (a2) is preferably used because it produces a propylene-based polymer having a high vinyl terminal ratio.

[In general formula (a2), R ²¹ and R ²² are each independently a hydrocarbon group having 1 to 6 carbon atoms. R ²³ and R ²⁴ are each independently 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 from these. show. Q ²¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, or a silylene group or germylene group optionally having a hydrocarbon group having 1 to 20 carbon atoms, and M ²¹ represents zirconium or hafnium. wherein X ²¹ and Y ²¹ are each independently 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, It represents a halogenated hydrocarbon group, an amino group or an alkylamino group having 1 to 20 carbon atoms. ]

R ²¹ and R ²² above are each independently a hydrocarbon group having 1 to 6 carbon atoms, preferably an alkyl group, 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, preferably methyl , ethyl, and n-propyl.

In addition, R ²³ and R ²⁴ are each independently halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a C 6-30 carbon atom optionally containing a plurality of hetero elements selected from these. , preferably an aryl group having 6 to 24 carbon atoms. Such aryl groups include a phenyl group, a biphenylyl group, and a naphthyl group 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, 3,5-dichloro-4-trimethylsilylphenyl and the like.

Q ²¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms that bridges two conjugated five-membered ring ligands via a carbon atom having 1 or 2 carbon atoms that binds two five-membered rings, or carbon It represents either a silylene group or a germylene group which may have 1 to 20 hydrocarbon groups. When two hydrocarbon groups are present on the silylene group or germylene group described above, they may bond together to form a ring structure.

Specific examples of Q ²¹ above include alkylene groups such as methylene, methylmethylene, dimethylmethylene and 1,2-ethylene; arylalkylene groups such as diphenylmethylene; silylene groups; methylsilylene, dimethylsilylene, diethylsilylene, di( alkylsilylene groups such as n-propyl)silylene, di(i-propyl)silylene and di(cyclohexyl)silylene; (alkyl)(aryl)silylene groups such as methyl(phenyl)silylene; arylsilylene groups such as diphenylsilylene; Alkyloligosilylene groups such as methyldisilylene; germylene groups; alkylgermylene groups in which silicon in the above divalent hydrocarbon group having 1 to 20 carbon atoms is substituted with germanium; (alkyl)(aryl)germylene group; an arylgermylene group and the like.
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 preferable, and an alkylsilylene group and an alkylgermylene group are particularly preferable.
Further, ^M21 is zirconium or hafnium, preferably hafnium.

The above X ²¹ and Y ²¹ are ancillary ligands and react with component (B) as a cocatalyst to produce an active metallocene capable of olefin polymerization. Therefore, the types of ligands of X ²¹ and Y ²¹ are not limited as long as this object is achieved, 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 of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, an oxygen-containing hydrocarbon group of 1 to 20 carbon atoms, an amino group or an alkylamino group of 1 to 20 carbon atoms represents

Non-limiting examples of the metallocene compound represented by the general formula (a2) include the following.
However, only typical exemplary compounds are described to avoid a large number of complicated examples. In addition, although compounds having hafnium as the central metal have been described, it is obvious that similar zirconium compounds can also be used, and that various ligands, cross-linking groups, or ancillary ligands can be optionally used.
(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 so on.

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.

Also, particularly preferably, 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, 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 ion-exchange layered silicate that 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. Preferred are ion-exchange layered silicates.

2-1. Compound Forming an Ion Pair with the Catalyst Component (A) Examples of the compound that forms an ion pair by reacting with the catalyst component (A) include an aluminum oxy compound, a boron compound, and the like. Specific examples include compounds represented by the following general formulas (I) to (III).

In general formulas (I), (II) and (III) above, R ⁹¹ , R ¹⁰¹ and R ¹¹¹ are hydrogen atoms or hydrocarbon groups, preferably hydrocarbon groups having 1 to 10 carbon atoms, particularly preferably carbon atoms. It represents a hydrocarbon group of numbers 1-6. Moreover, a plurality of R ⁹¹ , R ¹⁰¹ and R ¹¹¹ may be the same or different. P is an integer of 0-40, preferably 2-30.
The compounds represented by formulas (I) and (II) are also called aluminoxanes, and among these, methylaluminoxane and methylisobutylaluminoxane are preferred. The above aluminoxanes may be used in combination within each group and between each group. And 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 the general formula (III) is a trialkylaluminum or two or more trialkylaluminums and an alkylboronic acid represented by the general formula R ¹¹² B(OH) ₂ at a ratio of 10:1 to It can be obtained by a 1:1 (molar ratio) reaction.
Boron compounds include complexes of cations such as carbonium cations and ammonium cations with organic boron compounds such as triphenylboron, tris(3,5-difluorophenyl)boron and tris(pentafluorophenyl)boron, or Various organoboron compounds such as tris(pentafluorophenyl)boron can be mentioned.

2-2. Ion-exchange layered silicate In the present invention, the ion-exchange layered silicate used as a raw material (hereinafter sometimes simply abbreviated as silicate) means that layers formed by ionic bonds etc. It refers to a silicate compound that has a crystal structure that is stacked in parallel by force, has interlayer ions between layers, and is capable of exchanging the contained interlayer ions.
Most silicates are naturally produced mainly as main components of clay minerals. It is common to disperse/swell in water and purify by difference in sedimentation speed, etc., but it is not necessary to completely remove contaminants, contaminants other than ion-exchange layered silicate ( quartz, cristobalite, etc.). Depending on the type, amount, particle size, crystallinity, and dispersion state of these contaminants, they may be preferable to pure silicate, and such a composite is also an ion-exchange layered silicate of the catalyst component (B). include.
In addition, the silicate used in the present invention is not limited to naturally occurring silicates, and may be artificially synthesized.

Specific examples of ion-exchangeable layered silicates include layered silicic acid having a 1:1 type structure or a 2:1 type structure described in Haruo Shiramizu, "Clay Mineralogy", Asakura Shoten (1988). salt.
The 1:1 type structure indicates a structure based on stacking of one layer of tetrahedral sheet and one layer of octahedral sheet, as described in "Clay Mineralogy".
The 2:1 type structure refers to a structure based on stacking two layers of tetrahedral sheets sandwiching one layer of octahedral sheets.
Specific examples of ion-exchange layered silicates having a 1:1 type structure include kaolin group silicates such as dickite, nacrite, kaolinite, metahalloysite and halloysite, and serpentine stones such as chrysotile, lizardite and antigorite. group silicates and the like.
Specific examples of ion-exchange layered silicates having a 2:1 type structure include smectite group silicates such as montmorillonite, beidellite, nontronite, saponite, hectorite and stevensite, and vermiculite group silicates such as vermiculite. Examples include salt, mica group silicates such as mica, illite, sericite, and glauconite, attapulgite, sepiolite, palygorskite, bentonite, pyrophyllite, talc, and chlorite group. These may form a mixed layer.
Among these, those whose main component is an ion-exchangeable layered silicate having a 2:1 type structure are preferred. More preferably, the main component is a smectite group silicate, and even more preferably, the main component is montmorillonite.
The type of the interlayer cation (the cation contained between the layers of the ion-exchangeable layered silicate) is not particularly limited. Alkaline earth metals of Group 2 of the periodic table such as is preferable.

The ion-exchange layered silicate may be used in a dry state, or may be used in a state of being slurried in a liquid.
Further, the shape of the ion-exchangeable layered silicate is not particularly limited, and may be a shape produced naturally or a shape at the time of artificial synthesis. may be used.
Of these, the use of a granulated ion-exchangeable layered silicate is particularly preferred because it provides good polymer particle properties when the ion-exchanged layered silicate is used as a catalyst component.
The ion-exchange layered silicate can be used as it is without any particular treatment, but chemical treatment is preferred. For the chemical treatment method of the ion-exchange layered silicate, the descriptions in paragraphs 0042 to 0071 of JP-A-2009-299046 can be referred to.

The catalyst component (B) preferably used in the present invention is a chemically treated ion-exchange layered silicate having an Al/Si atomic ratio of 0.01 to 0.25, preferably 0.03 to 0. 0.24, more preferably in the range of 0.05 to 0.23. The Al/Si atomic ratio appears to be an indicator of the acid treatment strength of the clay parts.
Aluminum and silicon in the ion-exchange layered silicate are measured by a method of preparing a calibration curve by chemical analysis according to the JIS method and quantifying with fluorescent X-rays.

3. Component (C)
The catalyst component (C) used in the present invention is an organoaluminum compound, preferably an organoaluminum compound represented by the following general formula (IV).
(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, hydrogen, an alkoxy group or an amino group, n is 1 to 3, m is 1 to 2 each represents an integer of ]
X is preferably chlorine when it is a halogen, an alkoxy group with 1 to 8 carbon atoms when it is an alkoxy group, and an amino group with 1 to 8 carbon atoms when it is an amino group.
An organic aluminum compound can be used individually or in combination of multiple types.
Specific examples of organoaluminum compounds include trimethylaluminum, triethylaluminum, tri-normal-propylaluminum, tri-normal-butylaluminum, triisobutylaluminum, tri-normal-hexylaluminum, tri-normal-octylaluminum, tri-normal-decyl-aluminum, diethylaluminum chloride, and diethylaluminum. Sesquichloride, diethylaluminum hydride, diethylaluminum ethoxide, diethylaluminum dimethylamide, diisobutylaluminum hydride, diisobutylaluminum chloride and the like. Among these, trialkylaluminums and alkylaluminum hydrides where m=1 and n=3 are preferred. More preferably, R is a trialkylaluminum having 1 to 8 carbon atoms.

4. Preparation of Catalyst The olefin polymerization catalyst used in the present invention contains each of the above catalyst components. These can be obtained by contacting them inside or outside the polymerization tank. The olefin polymerization catalyst may be prepolymerized in the presence of olefin.
Contacting of each catalyst component is usually carried out in an aliphatic hydrocarbon or aromatic hydrocarbon solvent. The contact temperature is not particularly limited, but it is preferably between -20°C and 150°C. As the order of contact, any suitable combination is possible, but particularly preferred ones for each catalyst component are as follows.
When using the catalyst component (C), before contacting the catalyst component (A) and the catalyst component (B), the catalyst component (A), the catalyst component (B), or the catalyst component (A) and the catalyst contacting both component (B) with catalyst component (C), or contacting catalyst component (A) with catalyst component (B) and simultaneously contacting catalyst component (C), or Although it is possible to contact catalyst component (C) after (A) and catalyst component (B) are contacted, preferably catalyst component (A) is contacted with catalyst component (B) before contacting catalyst component (B). It is a method of contacting either component (C).
Further, after contacting each catalyst component, it is possible to wash 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 catalyst component (A) used relative to 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 catalyst component (B).
The amount of the catalyst component (C) used relative to the catalyst component (A) is preferably 0.01 to 5×10 ⁶ in terms of the molar ratio of aluminum in the catalyst component (C) to the transition metal in the catalyst component (A). It is more preferably in the range of 0.1 to 1×10 ⁴ .

The branched propylene-based polymer of the present invention and the branched propylene-based polymer (Z) to be degraded comprise a catalyst component capable of producing a macromer and an ability to copolymerize the macromer with propylene. It can be produced by using a catalyst component having. Although it is possible to produce the branched propylene-based polymer of the present invention using a single catalyst component that simultaneously has the ability to produce this macromer and the ability to copolymerize the macromer and propylene, In order to efficiently produce the target branched propylene-based polymer (Z), a method using separate catalyst components having respective capabilities can be selected. That is, a branched propylene-based polymer having the requirements of the present invention is obtained by a method using component [A-1] having the ability to form a macromer and component [A-2] having the ability to copolymerize the macromer and propylene. Coalescence and production of the branched propylene-based polymer (Z) to be degraded are facilitated.
Therefore, the ratio of the component [A-1] and the component [A-2] to be used depends on the characteristics of the branched propylene-based polymer of the present invention and the branched propylene-based polymer (Z) to be degraded. The molar ratio of the transition metal [A-1] to the total amount of each component [A-1] and [A-2] is preferably 0.30 or more and 0.99 or less. be.
By changing this ratio, it is possible to adjust the balance between melt physical properties and catalytic activity. That is, the component [A-1] produces a low-molecular-weight terminal vinyl macromer, and the component [A-2] produces a high-molecular-weight polymer obtained by partially copolymerizing the macromer. Therefore, by changing the proportion of component [A-1], the average molecular weight, molecular weight distribution, bias of the molecular weight distribution to the low molecular weight side, very high molecular weight components, branching (amount, length, distribution) can be controlled, thereby controlling melt physical properties such as degree of strain hardening, melt tension, and elongational viscosity.
The molar ratio of the transition metal of component [A-1] to the total amount of component [A-1] and component [A-2] is preferably 0.30 or more, more preferably 0.40 or more, More preferably, it is 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, it is preferably 0.80 or less, more preferably 0.70 or less. Range.
Also, by using the component [A-1] within the above range, the balance between the average molecular weight and the catalytic activity with respect to the amount of hydrogen can be adjusted.

5. Prepolymerization The catalyst for olefin polymerization is preferably subjected to prepolymerization, which comprises contacting an olefin and polymerizing a minor amount. By carrying out the preliminary polymerization treatment, it is possible to prevent the formation of gel when the main polymerization is carried out. The reason for this is thought to be that the long chain branches can be uniformly distributed among the polymer particles when the main polymerization is carried out.
The olefin used for prepolymerization is not particularly limited, but ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, Examples include styrene, preferably propylene.
The olefin feeding method includes a feeding method in which the olefin is maintained in a prepolymerization tank at a constant rate or a constant pressure state, a method in which the olefin is fed at a constant rate and then maintained in a constant pressure state, a method in which the constant rate feeding is started again and further A combination of a method of changing the constant pressure state step by step, such as maintaining a constant pressure step, and an arbitrary method are possible.

Although the prepolymerization temperature and prepolymerization time are not particularly limited, they are preferably in the range of -20°C to 100°C and 5 minutes to 24 hours.
Regarding the amount of prepolymerization, the mass ratio of the prepolymerization polymer to the catalyst component (B) is preferably 0.01-100, more preferably 0.1-50.
In addition, the catalyst component (C) can be added during prepolymerization, and washing can be performed at the end of prepolymerization.
It is also possible to coexist with solids of inorganic oxides such as polymers such as polyethylene and polypropylene, silica and titania during or after the contact of each of the above catalyst components.
After prepolymerization, the catalyst may be dried. The drying method is not particularly limited, but examples include drying under reduced pressure, drying by heating, and drying by circulating a dry gas. These methods may be used alone, or two or more methods may be combined. good. The catalyst may be stirred, vibrated, or fluidized in the drying step.

6. Propylene Polymerization Any polymerization mode may be adopted as long as the olefin polymerization catalyst and the monomer are efficiently brought into contact with each other.
Specifically, the slurry polymerization method using an inert solvent, the bulk polymerization method using propylene as a solvent without substantially using an inert solvent, the solution polymerization method, or the gaseous polymerization of each monomer without substantially using a liquid solvent. A vapor phase polymerization method or the like can be employed to maintain the
Further, a method of conducting continuous polymerization or batchwise polymerization is also applied.
In addition to single-stage polymerization, multi-stage polymerization of two or more stages is also possible.

In the case of the slurry polymerization method, saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, pentane, cyclohexane, benzene, toluene and the like are used singly or as a mixture as inert solvents.
The polymerization temperature is preferably 0°C or higher and 150°C or lower. In particular, in the case of bulk polymerization, the temperature is more preferably 40°C or higher, more preferably 50°C or higher. Moreover, the upper limit is preferably 80° C. or lower, more preferably 75° C. or lower.
In the case of gas phase polymerization, the temperature is preferably 40°C or higher, more preferably 50°C or higher. Moreover, 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 bulk polymerization, the pressure is more preferably 1.5 MPa or higher, more preferably 2.0 MPa or higher. Moreover, the upper limit is preferably 4.0 MPa or less, more preferably 3.5 MPa or less.
In the case of gas phase polymerization, the pressure is preferably 1.5 MPa or more, more preferably 1.7 MPa or more. Moreover, the upper limit is preferably 2.5 MPa or less, more preferably 2.3 MPa or less.

Furthermore, hydrogen is used as a molecular weight modifier in order to produce the branched propylene-based polymer of the present invention.
When the branched propylene-based polymer of the present invention is produced directly by polymerization without degradation, the MFR is increased by using a large amount of hydrogen. In this case, the amount of hydrogen to be used is in the range of 1.0×10 ⁻⁵ to 1.0×10 ⁻² in terms of molar ratio of hydrogen to propylene, preferably more than 1.0×10 ⁻⁴ 1. It is preferable to use in the range of 0×10 ⁻² or less.
The polymer produced from the component [A-1] shown above 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 large amount of hydrogen , the molecular weight of the polymer produced decreases. Further, the component [A-1] produces a terminal vinyl macromer, and the component [A-1] that produced the macromer itself is copolymerized to produce a branched polymer. On the other hand, the component [A-2] does not form a macromer by itself, and copolymerizes to form a branched polymer only when the macromer produced by the component [A-1] approaches the component [A-2]. . That is, the branching density of the polymer derived from component [A-2] is lower than that of the polymer derived from component [A-1] due to the difference in contact efficiency with the terminal vinyl macromer.
Therefore, if a large amount of hydrogen is used, the molecular weight distribution spreads to the low molecular weight side so that the polymer generated in component [A-2] exists more on the low molecular weight side than the polymer generated in component [A-1]. , and the branch density on the low molecular weight side becomes low. On the other hand, since a large amount of the polymer derived from the component [A-1] exists on the high molecular weight side, the branch density on the high molecular weight side falls within a specific range.
Also, the branched propylene-based polymer of the present invention can be produced by degrading the branched propylene-based polymer (Z). When the branched propylene-based polymer (Z) is produced, the MFR is reduced by using a small amount of hydrogen. In this case, the amount of hydrogen used is preferably in the range of 1.0×10 ⁻⁶ to 1.0×10 ⁻⁴ in terms of molar ratio of hydrogen to propylene.
When the amount of hydrogen used is small, the polymer produced from component [A-2] exists on the higher molecular weight side than the polymer produced from component [A-1]. At this time, the polymer derived from the component [A-1] having a high branching density exists on the low molecular weight side. By degrading the branched propylene-based polymer (Z) having such a branching distribution, the branched propylene-based polymer of the present invention can be produced so as to satisfy the characteristic (3).
As described above, the branched propylene-based polymer of the present invention can be produced directly from polymerization so as to have the branch distribution of characteristic (3), or a branched propylene-based polymer (Z) having a small MFR can be It can also be produced by degradation. Among them, it is preferable to degrade the branched propylene-based polymer (Z).

7. Degradation When a step of degrading the branched propylene-based polymer (Z) with an organic peroxide is used, the MFR can be adjusted by degrading, and the MFR of the branched propylene-based polymer (Z) can be reduced to It can be 10 to 1000 times larger.
The degradation method for adjusting the MFR is preferably an organic peroxide of 0.005 to 2.00 parts by weight, more preferably 0.100 to 1.00 parts by weight, based on 100 parts by weight of the resin. may be heated and kneaded at a temperature equal to or higher than the melting temperature of the resin, for example, 180 to 300° C. Any method can be employed, but it is particularly preferable to carry out in an extruder. In order to uniformly disperse the organic peroxide in the branched propylene-based polymer, the two may be thoroughly mixed in advance using a mixer such as a Henschel mixer or a ribbon blender before the two are heated and kneaded. . Furthermore, in order to improve the dispersibility of the organic peroxide, a mixture of the organic peroxide and a suitable medium can also be used.
Organic peroxides used at that time include benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 1,1-bis-(t-butylperoxy))- 3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)octane, n-butyl-4,4-bis(t-butyl peroxy)valerate, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2 ,5-di(t-butylperoxy)-3-hexyne, 1,3-bis(t-butylperoxyisopropyl)benzene, α,α'-bis(t-butylperoxyisopropyl)benzene, t-butyl -hydroperoxide, cumene hydroperoxide, lauroyl peroxide, di-t-butyl-diperoxyphthalate, t-butylperoxymaleic acid, t-butylperoxyisopropylcarbonate, isopropylpercarbonate and the like.
These can be used in combination of not only 1 type but 2 or more types. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, 1,3 - At least one selected from the group consisting of bis(t-butylperoxyisopropyl)benzene and α,α'-bis(t-butylperoxyisopropyl)benzene uniformly degrades in the kneader It is particularly preferable because it can be performed.

III. Uses of branched propylene-based polymer The branched propylene-based polymer of the present invention can be melt-kneaded by heat using a melt-kneader, and then cut into pellets to be used as a molding material. The branched propylene-based polymer of the present invention may optionally contain known antioxidants, ultraviolet absorbers, antistatic agents, nucleating agents, lubricants, flame retardants, antiblocking agents, coloring agents, and inorganic substances. Alternatively, various additives such as organic fillers and various synthetic resins can be blended.
In addition, the branched propylene-based polymer of the present invention has both a nano-sized fiber diameter and a high uniformity of the fiber diameter, and is resistant to fiber breakage and is easy to mold. can be suitably used in fields where finer fiber diameter is required.
Meltblown molding is a well-known method, and is widely used, for example, in the production of polyolefin-based resin nonwoven fabrics with small fiber diameters. In meltblown molding, after a raw material is melted by an extruder, a molten strand is extruded into a heated air stream from a spinning nozzle head having a hole diameter of several tens to several hundreds of μm and several tens to several thousands of holes. The melted strands are thinned by this air stream, collected on a collection device such as a conveyor, and wound up on a roll to obtain a nonwoven fabric.

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

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

(2) Preparation of catalyst (2-a) Chemical treatment of ion-exchange layered silicate 645.1 g of distilled water and 82.6 g of 98% sulfuric acid were placed in a 1 L three-necked flask equipped with a stirring blade and a reflux device. The temperature was raised to 95°C.
Commercially available montmorillonite (Benclay KK manufactured by Mizusawa Chemical Industry Co., Ltd., Al = 9.78 mass%, Si = 31.79 mass%, Mg = 3.18 mass%, Al / Si (molar ratio) = 0.320, An average particle size of 14 μm) was added, and the reaction was allowed to proceed at 95° C. for 320 minutes. After 320 minutes, 0.5 L of distilled water was added to stop the reaction and filtered to obtain 255 g of a solid cake.
1 g of this cake contained 0.31 g of chemically treated montmorillonite (intermediate). The chemical composition of the chemically treated montmorillonite (intermediate) was Al = 7.68 wt%, Si = 36.05 wt%, Mg = 2.13 wt%, Al/Si (molar ratio) = 0.222.
1545 g of distilled water was added to the above 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 reacted at 40° C. for 1 hour. After 1 hour, the reaction slurry was filtered and washed with 1 L of distilled water three times to obtain a cake-like solid again.
The collected cake was dried to obtain 80 g of chemically treated montmorillonite. The chemical composition of this chemically treated montmorillonite is Al = 7.68 mass%, Si = 36.05 mass%, Mg = 2.13 mass%, Al / Si (molar ratio) = 0.222, Li = 0.53 % by mass.

(2-b) Prepolymerization 150 kg of the chemically treated montmorillonite obtained as described above was placed in a reactor having an internal volume of 1 m ³ , and 2832 L of hexane was added to form a slurry, and 74.4 kg (375 mol) of triisobutylaluminum was added thereto. was added over 85 minutes and stirred for 60 minutes. After that, it was washed with hexane to 1/32, and the total volume was adjusted to 900L.
The slurry solution containing this 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 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. , stirring was continued for 60 minutes.
Then, 9.758 kg (26.61 mol) of tri-n-octylaluminum was added and stirred for 6 minutes, and then 0.064 kg of triisobutyl aluminum (a toluene solution with a concentration of 0.648% by mass) was added to 240 L of toluene in another vessel equipped with a stirrer. 9.88 kg, 0.32 mol) of rac-dichloro[1,1′-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-i-propylphenyl)indenyl }] A solution prepared by adding 1.768 kg (1.89 mol) of hafnium was added, 100 L of toluene was added, and stirring was continued for an additional 20 minutes.
After that, 2387 L of hexane was added to raise the internal temperature of the reactor to 40°C, and then 328.1 kg of propylene was fed over 240 minutes to carry out prepolymerization while maintaining 40°C. Thereafter, the propylene feed was stopped, and residual polymerization was carried out at 40° C. for 80 minutes.
After the residual polymerization was completed, the stirring was stopped and the content was allowed to settle and settle. The supernatant was removed so that the solution volume became 1,500 L, 12.7 kg of triisobutylaluminum was added, 3,974 L of hexane was added again, and the mixture was stirred.
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 were added thereto.
After that, the reaction solution was transferred to a dryer and dried at 40° C. for 9 hours.
As a result, 465 kg of dry prepolymerized catalyst was obtained. The prepolymerization ratio (value obtained by dividing the amount of prepolymerized polymer by the amount of solid catalyst) was 2.1. This prepolymerized catalyst was referred to as catalyst 1.

(3) Polymerization After sufficiently replacing the inside of a stirred high-pressure reactor (L/D = 1.2) with an internal volume of 100 ^m3 with propylene, sufficiently purified liquefied propylene was supplied at 20 T/hr and hydrogen at 0.110 kg/hr. hr,
Triisobutylaluminum was continuously introduced at a flow rate of 80 kg/hr and the temperature was maintained at 70±0.1°C.
When the MFR of the branched propylene-based polymer stabilized within the range of ±0.5 g/10 minutes, the branched propylene-based polymer (Z) (powder) was recovered.
The obtained branched propylene-based polymer (Z) (powder) had an MFR of 7.9, an Mw/Mn of 4.7, an Mz/Mw of 3.6, a W _1M of 4.1% by mass, and g'( M _abs pt) was 1.0, g′(Mw _abs ) was 0.91, g′(Mz _abs ) was 0.87, g′(million)=0.86.

(4) Degradation and granulation To 100 parts by mass of the powder of the branched propylene-based polymer (Z) obtained above, '-di-t-butyl-4'-hydroxyphenyl)propionate]methane (trade name: IRGANOX1010, manufactured by BASF Japan Ltd.) 0.125 parts by mass, a phosphite antioxidant Tris (2,4 -Di-t-butylphenyl) phosphite (trade name: IRGAFOS 168, manufactured by BASF Japan Co., Ltd.) 0.125 parts by mass, Perbutyl P-40 (trade name, Japan), an organic peroxide used as a molecular weight depressant 0.250 parts by mass of α,α'-di(t-butylperoxy)diisopropylbenzene, manufactured by Yusha Co., Ltd.), and stirred for 3 minutes with a high-speed stirring mixer Henschel mixer (trade name, manufactured by Nippon Coke Industry Co., Ltd.). Mixed. Then, using a twin-screw extruder KZW-15 (manufactured by Technobel, screw diameter 15 mm), the screw rotation speed is 400 rpm, and the kneading temperature is 80, 120, 230 ° C. from the bottom of the hopper (the same temperature until the die exit). Melt-kneaded. The molten resin extruded from the strand die was taken out while being cooled and fixed in a cooling water tank, and the strand was cut and pelletized using a strand cutter.
Various analyzes were performed using the obtained pellets. The results are shown in Table 1.

[Examples 2-3]
In (3) polymerization of Example 1, the same procedure as in Example 1 was performed except that the amount of the organic peroxide was changed to 0.375 parts by mass in Example 2 and 0.500 parts by mass in Example 3. to obtain pellets.
Various analyzes were performed using the obtained pellets. The results are shown in Table 1.

[Comparative Examples 1 to 3]
Used as a molecular weight depressant for linear polymer propylene homopolymer FY6Q (trade name, manufactured by Japan Polypropylene Corporation, MFR = 3 g/10 min, Tm = 160°C, g' (Mz _abs ) = 1.00). Perbutyl P-40 (trade name, manufactured by NOF Corporation, α,α'-di(t-butylperoxy)diisopropylbenzene), which is an organic peroxide that can be , manufactured by Nippon Coke Kogyo Co., Ltd.) for 3 minutes. Then, using a twin-screw extruder KZW-15 (manufactured by Technobel, screw diameter 15 mm), the screw rotation speed is 400 rpm, and the kneading temperature is 80, 120, 230 ° C. from the bottom of the hopper (the same temperature until the die exit). Melt-kneaded. The molten resin extruded from the strand die was collected while being cooled and fixed in a cooling water bath, and the strand was cut using a strand cutter to pelletize the linear polymer.
The amount of the organic peroxide per 100 parts by mass of the propylene homopolymer was adjusted to 0.375 parts by mass in Comparative Example 1, 0.500 parts by mass in Comparative Example 2, and 0.750 parts by mass in Comparative Example 3.
Various analyzes were performed using the obtained pellets. The results are shown in Table 1.

[Physical property measurement, analysis]
Physical property measurements and analyzes of the polymers of Examples and Comparative Examples were carried out according to the following methods. Table 1 shows physical property measurements and analysis results.
(1) Melt flow rate (MFR):
It was measured according to the melt flow rate of the polypropylene test method of JIS K7210 (test conditions: 230°C, load 2.16 kgf). The unit is g/10 minutes.
(2) Molecular weight and molecular weight distribution (Mw, Mn, Mz, Mw/Mn, Mz/Mw, W _1M ):
It was measured by gel permeation chromatography (GPC) by the method described in the specification above.
(3) 3D-GPC (g'(M _abs pt), g'(Mw _abs ), g'(Mz _abs ), g'(1M))
A GPC apparatus equipped with a differential refractometer (RI) and a viscosity detector (Viscometer) as a GPC apparatus to which a differential refractometer (RI), a viscosity detector (Viscometer) and a multi-angle laser light scattering detector (MALLS) are connected (Waters, Alliance GPCV2000) and a multi-angle laser light scattering detector (Yatt Technology, DAWN-E), and measured by the method described in this specification.

(4) Measurement of dynamic viscoelasticity ARES-G2 manufactured by TA Instruments was used as a device for measuring dynamic viscoelasticity.
The propylene-based polymer was compression-molded with a press at 180° C. for 5 minutes so as not to contain air bubbles, to obtain a disk-shaped measurement sample having a thickness of 2.0 mm and a diameter of 25 mm. Sample measurement is performed by using a parallel disk with a diameter of 25 mm that is kept at 180°C, compressing a sample for measurement with a thickness of 2.0 mm to a thickness of 1.5 mm, and placing it with a gap of 1.5 mm. 180 ° C., 10% strain, frequency range from 0.01 rad/sec to 100 rad/sec, measurement points are stored as 5 points per ω digit Elastic modulus (G') and loss modulus (G'') were measured.

(5) Melting point (Tm):
A propylene-based polymer powder was sandwiched between press plates, preheated at 190° C. for 2 minutes, and then pressed at 5 MPa for 2 minutes. Then, after cooling at 0° C. and 10 MPa for 2 minutes, a sheet was obtained.
Using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.), 5 mg of the sample piece of the sheet obtained above was packed in an aluminum pan, heated from room temperature to 200 ° C. at a heating rate of 100 ° C./min, and heated for 5 minutes. After holding, the temperature is lowered to 20°C at 10°C/min to determine the crystallization temperature (Tc) as the maximum crystal peak temperature (°C) when crystallized, and then raised to 200°C at 10°C/min. The melting point (Tm) was determined as the maximum melting peak temperature (°C) when warmed.

(6) mesopentad fraction (mmmm) of five chains of propylene units measured by ¹³ C-NMR
Using the propylene-based polymer obtained above, the regularity was determined according to the following.
( ¹³ C-NMR measurement method)
[Sample preparation and measurement conditions]
200 mg of a sample was mixed with 2.4 mL of o-dichlorobenzene/deuterobrominated benzene (C ₆ D ₅ Br) = 4/1 (volume ratio) and hexamethyldisiloxane, which is a reference substance for chemical shift, and an NMR sample with an inner diameter of 10 mmφ. It was placed in a tube and uniformly melted with a block heater at 150°C.
The NMR measurement was carried out using a Bruker Biospin Model AV400 NMR apparatus equipped with a 10 mmφ cryoprobe.
The 13C-NMR measurement conditions were a sample temperature of 120° C., a pulse angle of 90°, a pulse interval of 15 seconds, and an accumulation count of 1024 times, and the measurement was performed by a broadband decoupling method.
The chemical shift was set to 1.98 ppm for the ¹³ C signal of hexamethyldisiloxane and the chemical shifts of the other ¹³ C signals were referenced to this.
[Method for calculating mesopentad fraction (mmmm)]
The mesopentad fraction (mmmm) of 5 chains of propylene units was obtained 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 ) Equation (3)
where I _mm represents the integrated intensity of the ¹³ C signal attributed to the bonding mode of the propylene unit triplets in mm, and the integrated intensity of the ¹³ C signal with chemical shifts in the range of 23.6-21.1 ppm, I _mrrm represents the integrated intensity of the ¹³ C signal in which the propylene unit penta-link is assigned to the mrrm bonding mode, and is the integrated intensity of the ¹³ C signal in the range of chemical shifts from 19.9 to 19.7 ppm.

[Fiber molding and evaluation]
(1) Molding Each propylene-based polymer obtained above was melt-blown molded under the following conditions to obtain a nonwoven fabric having a basis weight of 20 g/m ² .
Die; die size: 10 inches, nozzle holes: 360, nozzle diameter: 0.3 mm
Spinning conditions; spinning temperature: 260°C, air temperature: 280°C, air flow rate: 5500 L/min, discharge rate: 0.15 g/min/hole fiber collection conditions; ejector-conveyor distance: 200 mm

(2) Evaluation (2-1) Formability Since the fiber diameter of the fiber produced from each propylene-based polymer obtained above is nano-sized, the thread breakage can be evaluated by visual inspection immediately below the die. I can't confirm because I don't have one. However, if yarn breakage occurs during yarn forming, a phenomenon occurs in which the broken yarn flies in the air.

(2-2) Uniformity of fiber diameter and fiber diameter
The obtained fibrous nonwoven fabric raw fabric was photographed at a magnification of 150 using a shape measuring laser microscope "VK-X200" manufactured by Keyence Corporation, and the single yarn diameter was measured at n = 60 from the image.
Furthermore, the uniformity of the fiber diameter was derived from the standard deviation of the obtained fiber diameter.
The evaluation results are also shown in Table 1.

FIG. 3 shows the relationship between the angular frequency ω dependence of the complex viscosity η ^* (ω) and the MFR. From Examples 1 to 3 and Comparative Examples 1 to 3, the branched propylene polymer of the present invention has a ratio [η ^* (0.1 rad/s ) / η ^* (100 rad/s)] is large in proportion to fluidity, the balance between fluidity and melt strength is improved, and both nano-sized fiber diameter and high uniformity of fiber diameter are achieved. It can be seen that it is possible to provide a propylene-based polymer that is resistant to thread breakage and is easy to mold.

Claims (5)

A branched propylene-based polymer having the following properties (1) to (4).
Characteristic (1): The melt flow rate (MFR) measured at a temperature of 230° C. and a load of 2.16 kg is greater than 100 g/10 minutes and not more than 1000 g/10 minutes.
Characteristic (2): The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by gel permeation chromatography (GPC) is 2.0 or more and 4.0 or less, and The ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) is 1.5 or more and 4.0 or less.
Characteristic (3): In the molecular weight distribution curve obtained by 3D-GPC, the branching index g' (Mz _abs ) at the absolute z-average molecular weight Mz _abs is 0.70 or more and 0.95 or less.
Characteristic (4): The angular frequency ω dependence of complex viscosity η ^* (ω) in dynamic viscoelasticity measurement and MFR satisfy the following relational expression (1).
log[η ^* (0.1rad/s)/η ^* (100rad/s)]≧−0.19×log(MFR)+0.58 Equation (1)
(Here, η ^* (0.1 rad/s) is the complex viscosity at ω=0.1 rad/s, and η ^* (100 rad/s) is the complex viscosity at ω=100 rad/s.) The branched propylene-based polymer according to claim 1, further having the following property (5).
Characteristic (5): In the integral molecular weight distribution curve obtained by GPC, the ratio (W _1M ) of components having a molecular weight of 1,000,000 or more is 0.10% by mass or less. 3. The branched propylene-based polymer according to claim 1, further having the following property (6).
Characteristic (6): Melting point (Tm) measured with a differential scanning calorimeter (DSC) is 145° C. or higher. The branched propylene-based polymer according to any one of claims 1 to 3, further having the following property (7).
Characteristic (7): The mesopentad fraction (mmmm) of 5 chains of propylene units measured by ¹³ C-NMR is 93% or more. The branched propylene-based polymer according to any one of claims 1 to 4, which is degraded with an organic peroxide.

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