JP2000109568A - Polyolefin resin composition - Google Patents

Abstract

(57) [Problem] To provide a polypropylene resin composition having excellent melting properties and good physical properties and moldability. SOLUTION: At least one or more Si—H in a molecule is provided.
The poly-α-olefin composition such as crystalline polypropylene containing silicon caused by the polysiloxane having a bond is heated and melt-mixed in the presence of an alkali metal or alkaline earth metal alkoxy compound to obtain physical properties and moldability. To obtain a good polypropylene resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyolefin resin composition. More specifically, the present invention relates to a polyolefin resin composition having physical properties suitable for extrusion molding.

[0002]

2. Description of the Related Art Polyolefins have been used in a wide range of applications such as injection moldings and extrusion moldings because of their excellent moldability. Among the polyolefins, polypropylene has recently been particularly demanded because it has excellent resin properties suitable for various uses in addition to excellent moldability. For example, extrusion molded products of various shapes by extrusion molding, various hollow molded products by blow molding,
Its applications are extremely wide, such as films and sheets utilizing film forming ability.

[0003] In the field of polyolefin molded articles, various improvements have been made so far in order to open up new markets and respond to market demands. The improvements cover the resin manufacturing process, mixing of resins, mixing with additives, and modification of the resin. For example, to improve the physical properties of polypropylene, or
A method of polymerizing polypropylene in multiple stages for the purpose of improving flowability during foaming or a method of melting and mixing a plurality of resins having different properties is known, and for the purpose of improving the same flowability, crosslinking polypropylene. Various things are also performed. For example, a method of mixing a bifunctional monomer and a radical initiator with a polyolefin and a method of irradiating a molded product with radiation are known, and polyolefin particles containing a copolymer of alkenylsilane and olefin are known. ,
A method of mixing and melt-molding polyolefin particles or the like containing a specific hydrosilylation catalyst has also been attempted.

In extrusion molding, which is a main application of polyolefins, especially polypropylene, attention has been paid to the properties of resins when they are melted as one of various improvements. The properties of the molten resin are the stability of the molten resin during molding,
It is an important factor that affects the molding cycle, appearance and physical properties of the molded product. Although various efforts have been made to improve this problem as described above, this is a field where further improvement is desired.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have diligently worked on the development of a molding resin having melting characteristics suitable for extrusion molding, and have reached the present invention. That is, the present invention provides a resin composition that has excellent melting properties in extrusion molding and that exhibits excellent moldability.

[0006]

According to the present invention, there is provided a poly-α-olefin composition containing from 4 ppm to 3800 ppm of silicon atoms derived from a polysiloxane having at least one Si—H bond in a molecule. Provided is a polyolefin resin composition obtained by heat-melting and kneading in the presence of an alkaline earth metal alkoxy compound. Further, the present invention provides a poly-α-olefin which is a mixture of a polysiloxane having at least one or more Si-H bonds in a molecule and at least one poly-α-olefin.
Provided is a polyolefin resin composition obtained by heating and kneading an olefin composition in the presence of an alkali metal or alkaline earth metal alkoxy compound.

In the above polyolefin resin composition provided by the present invention, any of the poly α-olefins is
Provided is a polyolefin resin composition which is crystalline polypyrropyrene satisfying the following properties. The melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg is 0.01 to 50 g / 10 min. The content of a high molecular weight component having an intrinsic viscosity [η] of 8 to 13 dl / g is 15 to 50% by weight. And the isotactic pentad fraction (mmmm) measured by 13C-NMR is 0.970 or more.

In addition, the present invention provides a mixture of a polysiloxane having at least one Si—H bond in a molecule and a crystalline polypropylene having the following characteristics:
Alternatively, there is provided a polyolefin resin composition obtained by heat-melting and mixing a mixture of the crystalline polypropylene and another poly-α-olefin in the presence of an alkali metal or alkaline earth metal alkoxy compound. The melt flow rate (MFR) measured under a load of 2.16 kg at 230 ° C. is 0.01 to 50 g / 10 min. The content of a high molecular weight component having an intrinsic viscosity [η] of 8 to 13 dl / g is 15 to 50% by weight. Isotactic pentad fraction (mmmm) measured by 13C-NMR is 0.970 or more

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as the polysiloxane having at least one Si—H bond in a molecule, an oligomer or polymer having a siloxane structure is preferably used. Can be used. The Si-H bond in the molecule may be present in either the main chain or the terminal.

[0010] Polysiloxane is a general term for polymers having a siloxane bond -Si-O- in the main chain, and can be represented by the following general formula. _{- (- SiR 2 0-) n} - wherein R represents an example, an alkyl group or an aryl group,
n represents a number of 2 to 2000. Polysiloxanes in which R in the above formula is a methyl group or a phenyl group are well known.

In the polysiloxane having at least one Si—H bond in the molecule used in the present invention, a part of the Si—R bond in the main chain of the polysiloxane represented by the above formula is Si A typical example is a hydrogen polysiloxane substituted with -H. In particular, a preferable example is a methylhydrogenpolysiloxane in which a part of Si-CH3 bonds in the main chain of dimethylpolysiloxane in which R in the formula is methyl is replaced by Si-H. As described above, at least one or more Si atoms are present in the molecule of the present invention.
The polysiloxane having an —H bond may be a compound in which H is not at the main chain but at the terminal.

The polysiloxane having at least one Si—H bond in the molecule preferably has a molecular weight in an oligomer or polymer region. The degree of polymerization of the polysiloxane is expressed by the number n in the above formula, and 2 Or 200
0, preferably 3 to 100 is desirable. The amount of Si—H bonds in the polysiloxane having at least one Si—H bond in a molecule preferably used in the present invention is 1 to 100% based on the total amount of Si—R and Si—H bonds. It is good to be. It is.

The α-olefin homopolymer or copolymer (hereinafter referred to as polyα-olefin) to be mixed with the polysiloxane having at least one Si—H bond in the molecule is a homopolymer of α-olefin. A coalescence or a copolymer can be exemplified. Specifically, a homopolymer of propylene, a random or block copolymer of propylene and ethylene, a copolymer of ethylene and butene-1, a copolymer of ethylene and 4-methyl-1-pentene, Copolymers of ethylene and hexene and copolymers of ethylene and octene can be mentioned. Above all,
A propylene homopolymer and a random or block copolymer of propylene and ethylene are preferred.

The α-olefin homopolymer or copolymer to be used can be obtained by homopolymerizing the α-olefin using a known catalyst or by copolymerizing in the presence of a comonomer. It is also possible to appropriately select a commercially available poly-α-olefin. The melt flow rate (MFR) of the polymer used at 230 ° C. under a load of 2.16 kg is usually 0.01 to 100, preferably 0.01 to 5
0.

In the obtained molecule, at least one or more S
A poly-α-olefin composition comprising a mixture of a polysiloxane having an iH bond and a poly-α-olefin is further mixed with one or more other same or different poly-α-olefins to form a poly-α-olefin composition. Is also good.

The mixing ratio in the poly-α-olefin composition comprising a mixture of a polysiloxane having at least one or more Si—H bonds in the molecule and a poly-α-olefin can be appropriately selected.

In the present invention, the amount of the polysiloxane added is 1/100 relative to 1 part by weight of the polyα-olefin.
000 parts by weight or more, preferably 1 / 10,000 parts by weight or more. Here, the upper limit of the amount of the polysiloxane is not particularly limited, but it is not necessary to add the polysiloxane excessively. In terms of the amount of silicon derived from a polysiloxane having at least one Si-H bond in the molecule, 4p
pm to 3800 ppm. The amount of silicon can be measured by X-ray fluorescence.

In preparing a mixture with a poly-α-olefin having at least one Si—H bond in the molecule, the melting property can be improved by using crystalline polypropylene having the following characteristics as the poly-α-olefin. An improved resin composition can be obtained, and a molded article having improved physical properties can be obtained. The melt flow rate (MFR) measured under a load of 2.16 kg at 230 ° C. is 0.01 to 50 g / 10 min, and the intrinsic viscosity [η] is 8 to 13 dl / g. %, And an isotactic pentad fraction (mmmm) measured by 13C-NMR of 0.970 or more.

Further, the crystalline polypropylene preferably has the following properties. Gel permeation chromatography (GPC)
The molecular weight distribution Mw / Mn measured in the above is 6 or more and Mz /
Mw is 4 or more.

The crystalline polypropylene may be a homopolymer of propylene or a copolymer of propylene with ethylene or another monomer. Generally, a homopolymer of propylene is used, but when low-temperature impact strength is required, a block copolymer with ethylene is used, and when transparency is required, a random copolymer with ethylene is used. A suitable result can be expected when is used.

The melt flow rate (MFR) of the crystalline polypropylene in the present invention is 230 ° C., 2.16 k
It is in the range of 0.01 to 50 g / 10 minutes measured under a g load, but is preferably 0.05 to 35 g / 10 minutes.

The crystalline polypropylene contains 15 to 50% by weight of a high molecular weight component having an intrinsic viscosity [η] of 8 to 13 dl / g. Further, the intrinsic viscosity [η] is 8.5 to 8.5.
It is preferable that the content of the high molecular weight component of 12 dl / g is 15 to 45% by weight.

The crystalline polypropylene according to the present invention,
The isotactic pentad fraction (mmmm) measured by 13 C-NMR is 0.970 or more, and preferably 0.980 to 0.995. Here, the isotactic pentad fraction is an isotactic chain in a pentad unit in a crystalline polypropylene molecular chain measured using ¹³ C-NMR, and five consecutive propylene monomer units are used. The fraction of propylene monomer units at the center of the meso-linked chain. In practice, ¹³ CN
It can be determined as a fraction occupied by the mmmm peak in all the absorption peaks in the methyl carbon region measured by the MR spectrum.

A more preferable property when the crystalline polypropylene is satisfied in the present invention is a molecular weight distribution measured by gel permeation chromatography (GPC). The ratio (Mw / M) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by the GPC method
n) is 6 or more, preferably 6 to 20, and the Z-average molecular weight (Mz) similarly measured by the GPC method.
The value indicated by the ratio (Mz / Mw) of the weight average molecular weight (Mw) is 4 or more, preferably 4 to 7. Satisfying this range indicates that the distribution is broader on the high molecular weight side than that of ordinary polypropylene. The crystalline polypropylene of the present invention only needs to satisfy the above characteristics, and the production method is not particularly limited.

An example of the method for producing the crystalline polypropylene according to the present invention is as follows: polypropylenes having different molecular weights are separately produced and melt-kneaded and blended, or polypropylenes having different molecular weights are produced by multi-stage polymerization. It is preferable to mix polypropylenes having different molecular weights. At this time, the effect of improving the physical properties is remarkably increased by using a composition containing a relatively low molecular weight polypropylene and a relatively high molecular weight polypropylene.

When the crystalline polypropylene is used in the present invention, at least one or more Si—H
The polysiloxane having a bond may be previously mixed with a poly-α-olefin other than the crystalline polypropylene and then mixed with the crystalline polypropylene, or may be directly mixed with the crystalline polypropylene. Further, after mixing with the crystalline polypropylene, it may be mixed with a poly-α-olefin other than the crystalline polypropylene. The ratio of the crystalline polypropylene to the total amount of the crystalline polypropylene and the poly-α-olefin other than the crystalline polypropylene is 1% by weight to 100% by weight, preferably 10% by weight to 100% by weight. When the crystalline polypropylene is used in the present invention, the poly-α-olefin other than the crystalline polypropylene is more preferably a poly-α-olefin containing [η] of less than 15% by weight of a high molecular weight component having a molecular weight of 8 to 13. Good results can be obtained.

Furthermore, if attention is paid to the melting characteristics of the polyolefin resin composition of the present invention, it is possible to keep the melt viscosity in the low shear rate region as high as possible while keeping the melt viscosity in the high shear rate region low. It is to provide a resin composition.

In the present invention, the poly-α-olefin composition obtained above is heated and melt-mixed in the presence of an alkaline earth metal alkoxy compound. Here, as the alkali metal or alkaline earth metal, lithium, sodium,
Examples thereof include potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, and barium. The alkoxy group is not particularly limited, but includes methoxy, ethoxy, propoxy, n-butoxy, sec.
-Butoxy, tert. -An alkoxy group having 1 to 8 carbon atoms such as butoxy, pentanoxy, hexanoxy, heptanoxy, octanoxy and cyclohexanoxy, or phenoxy, 4-methylphenoxy, 2,6-di-
Examples thereof include an aryloxy group having 6 to 20 carbon atoms such as tert-butyl-4-methylphenoxy. Further, an alkoxy group having a substituent derived from an alcohol such as benzyl alcohol, ethylene glycol, diethylene glycol, polyethylene glycol, ethylene glycol monomethyl ether, propylene glycol, dipropylene glycol, polypropylene glycol, and propylene glycol monomethyl ether can also be preferably exemplified.

In the present invention, the amount of the alkali metal or alkaline earth metal alkoxy compound to be used may be a catalytic amount, but is usually a polysiloxane having at least one Si—H bond in the molecule and a crystal. 0.00001 to 1% by weight, preferably 0.0001% by weight, based on the mixture with the functional polypropylene and the other poly-α-olefin.
~ 0.5% by weight is used.

In the present invention, the mixture of the above-mentioned copolymer of polysiloxane having at least one or more Si—H bond in the molecule with crystalline polypropylene and other α-olefin is treated with an alkali metal or alkaline earth metal. As a method of heat-melting and mixing in the presence of the alkoxy compound, all the above-mentioned components are mixed, and then charged into an extruder or a twin-screw kneader, followed by heat-melting and kneading. The contact temperature is about 150 to 300 ° C., and the contact time is 0.0
It takes about 5 to 20 minutes.

Upon mixing, if necessary, an antioxidant, a heat stabilizer, a weathering agent, an ultraviolet absorber, a radiation-resistant agent, an antistatic agent, a crystal nucleating agent, an inorganic filler, a lubricant, a plasticizer, a neutralizing agent ,
Of course, it is also possible to add various additives such as pigments and colorants that are usually used for olefin polymers. Further, auxiliary materials such as elastomers can be added to improve mechanical properties. Further, for the purpose of adjusting the molecular weight of the obtained polyolefin resin composition, upon mixing,
Compounds that generate radicals can also be added, and conventional radical generators such as benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, acetyl peroxide, lauroyl peroxide and the like, perbenzoic acid, perbenzoic acid T-butyl acid,
Peroxides such as 2,5-dimethyl-2,5-di-t-butylperoxyhexane and azo compounds such as azobisisobutyronitrile can be used.

The addition amount of these compounds is 0.00001 to 0.1% by weight based on a mixture of polysiloxane having at least one Si-H bond in a molecule, crystalline polypropylene and other poly α-olefin. %.

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. (1) Melt flow rate (hereinafter referred to as MFR): A
It conformed to STM-D1238 (230 ° C). (2) Gel permeation chromatography (GP
Measurement of molecular weight distributions Mw / Mn and Mz / Mw by C): weight average molecular weight (Mw), number average molecular weight (Mn),
The Z average molecular weight (Mz) was measured under the following conditions. That is, W
Using a 150C type GPC manufactured by Aters, a PLmlxedB column manufactured by Polymer Laboratories was attached.
400 μl of a sample having a polymer concentration of 0.15% by weight was supplied. The solvent is o-dichlorobenzene and the measurement temperature is 1
35 ° C. Then, Mw, Mn, and Mz were determined from a calibration curve prepared using standard polystyrene manufactured by Polymer Laboratories. For the analysis, analysis software (Millennium) manufactured by Waters was used. (3) Measurement of flexural rigidity: ASTM-D747-63
(20 ° C.).

Example 1 Polypropylene powder having an intrinsic viscosity [η] of 2.90 dl / g (brand name EB, manufactured by Grand Polymer Co., Ltd.) 10
0 parts by weight of methyl hydrogen polysiloxane (silicone oil manufactured by Shin-Etsu Chemical Co., Ltd., brand name KF
99) 0.3 parts by weight, potassium-tert.
-After adding 0.05 parts by weight of butoxide, 0.1 g of Irgafos 168 (manufactured by Ciba-Geigy) as an antioxidant
Parts by weight, 0.1% calcium stearate as a hydrochloric acid scavenger.
The mixture was heated and melt-kneaded at a screw rotation speed of 70 rpm at a temperature of 230 ° C. using a 50 mmφ single screw extruder to obtain pellets. The MFR of this pellet is 0.54 g
/ 10 minutes. Using a differential scanning calorimeter (hereinafter referred to as DSC), the crystallization temperature (hereinafter referred to as Tc) and melting point (hereinafter referred to as Tm) of the pellet, and an isothermal half-crystallization time at 125 ° C (hereinafter referred to as t1 / 2). ) Were measured, Tc was 113.3 ° C, Tm was 161.6 ° C,
t1 / 2 was 2.2 minutes. Further, using a conical disk-shaped rheometer (Rheology MR-500, cone angle 5 deg, disk diameter 20 mm), measuring temperature 230 ° C., measuring angular frequency 0.1 to 100 rad / sec. , Measured strain 1-10
% When the melt viscosity of the pellets was measured within the linear range of 100%. The melt viscosity at (high shear rate region) is 1150 Pa · s
At a measurement angular frequency of 0.019 rad / sec. The melt viscosity in (low shear rate region) was 68800 Pa · s.

Then, using the above-mentioned pellet, a thickness of 1 mm
Was prepared, and the flexural rigidity was measured. The value of the flexural rigidity was 15,400 kg / cm2. Comparative Example 1 Methyl hydrogen polysiloxane and potassium-t
ert. -Performed exactly as in Example 1, but without adding butoxide. The MFR of the obtained pellet is 0.28 g.
/ 10 min, Tc is 110.3 ° C, Tm is 160.7
° C and t1 / 2 were 5.0 minutes. Measurement angular frequency 1
00 rad / sec. Melt viscosity at 1250 Pa
S, the measurement angular frequency is 0.019 rad / sec. Was 62,600 Pa · s. The value of the bending rigidity of the injection sheet is 15,000k.
g / cm2.

In comparison with Example 1 and Comparative Example 1, in Example, both Tc and Tm slightly increased from Comparative Example 1, and t1 / Tm increased.
2 is shorter. Although there was almost no difference in the melt viscosity in the high shear rate region, the melt viscosity in the low shear rate region increased. Furthermore, the value of the bending rigidity also increased. From these facts, it is considered that the crosslinking reaction is progressing.

Example 2 Preparation of crystalline polypropylene (Preparation of solid titanium catalyst component) 4.8 kg of anhydrous magnesium chloride, 25.0 liters of decane and 2-
23.4 liters of ethylhexyl alcohol was charged into a 200 liter autoclave, and a heating reaction was performed at 130 ° C. for 2 hours to obtain a uniform solution. Thereafter, 11.1 kg of phthalic anhydride was added to the solution, and the mixture was further stirred and mixed at 130 ° C. for 1 hour to dissolve phthalic anhydride to obtain a uniform solution. After cooling the thus obtained homogeneous solution to room temperature, the whole solution was dropped into 200 liters kept at -20 ° C over 1 hour. After the completion of the dropwise addition, the temperature of the mixture was raised to 110 ° C. over 4 hours,
When the temperature reached 0 ° C., 2.7 g of diisobutyl phthalate was obtained.
One liter was added and the same temperature was maintained with stirring for 2 hours. After completion of the reaction for 2 hours, a solid portion was collected by hot filtration and washed with hexane at 110 ° C. Washing was sufficiently performed until the free titanium compound concentration in the washing solution became 0.1 mmol / L or less. A solid titanium catalyst component was obtained by the above method.

(Preparation of Prepolymerization Catalyst Component) Internal Volume 200
In a liter autoclave, 250 g of the above solid titanium catalyst component was placed in triethylaluminum (hereinafter referred to as TE).
3A) and 125 liters of heptane. Next, 1250 g of propylene was charged while maintaining the internal temperature at 10 ° C., and the mixture was stirred for 30 minutes. Then, 18 g of titanium tetrachloride was charged to obtain a slurry of a prepolymerized catalyst component.

(Implementation of Multi-Stage Polymerization) The first-stage polymerization was carried out by a continuous two-stage method using one polymerization vessel and the second-stage polymerization using four polymerization vessels. That is, 53 l / h of heptane, 5.4 g / h of the above prepolymerized catalyst component, 10.3 g / h of triethylaluminum, and dicyclopentyldimethoxysilane (500 g / h) as a catalyst were placed in a 500 l polymerization vessel-1. Hereinafter referred to as DCPMS)
Feed continuously at a rate of 0.9 gram / hour, temperature 60
Under a condition substantially free of hydrogen at ℃, propylene was continuously charged so as to keep the internal pressure of the polymerization reactor 1 at 0.76 MPa (7.8 kgf / cm 2, gauge pressure) (first stage). polymerization). Sampling of the slurry in the polymerization vessel-1
When the intrinsic viscosity [η] of polypropylene was measured,
It was 9.4 dl / g. Then, as the second stage polymerization,
Using four polymerization reactors having an internal volume of 500 liters, the slurry of the polymerization reactor 1 in which the first stage polymerization was carried out was continuously fed to the polymerization reactor 2 and further sequentially fed to the subsequent polymerization reactors to carry out polymerization. In the second-stage polymerization, the hydrogen concentration in the gas phase was increased to 30 vol. % And propylene and hydrogen were continuously supplied. After removing the unreacted monomer from the slurry exiting the polymerization vessel, heptane was centrifuged by a usual method, and 80 ° C., 9300 Pa
(70 mmHg, gauge pressure) for 10 hours to obtain a product. This product powder was obtained at a rate of 78 kg / hour. The MFR of this product was 4.0 g / 10 minutes.
The proportion of the polypropylene produced in the first-stage polymerization in the finally obtained polypropylene, calculated from the material balance, was 25 wt. %Met. The isotactic pentad fraction (hereinafter referred to as mm) measured by 13 C-NMR
mm) was 0.983, the molecular weight distribution Mw / Mn measured by gel permeation chromatography (GPC) was 18.9, and Mz / Mw was 5.6.

(Production and evaluation of resin composition) Polypropylene powder (manufactured by Grand Polymer Co., Ltd., brand name E)
Example 1 was carried out in exactly the same manner as in Example 1 except that the polypropylene obtained by the above method was used instead of B). The MFR of the obtained pellet was 5.6 g / 10 min, and Tc was 1
17.0 ° C., Tm was 162.7 ° C., and t1 / 2 was 0.9 minutes. The measurement angular frequency is 100 rad / sec. Has a melt viscosity of 261 Pa · s and a measured angular frequency of 0.1.
038 rad / sec. Melt viscosity at 6760P
a · s. The value of the bending rigidity of the injection sheet was 22,000 kg / cm 2. Compared with Comparative Example 2 shown below, both Tc and Tm increased,
t1 / 2 became shorter. Although there was almost no difference in the melt viscosity in the high shear rate region, the melt viscosity in the low shear rate region increased. Further, it can be seen that the value of the bending rigidity is also high.

Comparative Example 2 Methyl hydrogen polysiloxane and potassium-t
ert. -Performed exactly as in Example 2 without adding butoxide. The MFR of the obtained pellet was 7.1 g /
In 10 minutes, Tc is 114.0 ° C., Tm is 161.0 ° C.,
t1 / 2 was 3.0 minutes. In addition, measurement angular frequency 100
rad / sec. Melt viscosity at 219 Pa · s
At a measurement angular frequency of 0.038 rad / sec. Was 2450 Pa · s. The value of the bending rigidity of the injection sheet is 19,800 kg / c.
m2.

[0041]

The polypropylene resin composition of the present invention has
Since it has high rigidity and excellent melting properties, it exhibits excellent moldability and gives good physical properties to molded products, and is of high industrial value.

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Claims (6)

[Claims] 1. The method according to claim 1, wherein the silicon atom derived from the polysiloxane having at least one Si--H bond in the molecule is from 4 to 4.
A polyolefin resin composition characterized by being heated and melt-kneaded with a polyα-olefin composition containing 3800 ppm in the presence of an alkali metal or alkaline earth metal alkoxy compound. 2. The poly-α-olefin composition is a mixture of a polysiloxane having at least one Si—H bond in a molecule and at least one kind of poly-α-olefin. Item 4. The polyolefin resin composition according to Item 1. 3. The polyolefin resin composition according to claim 1, wherein one of the poly-α-olefins is crystalline polypyrropyrene satisfying the following properties. The melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg is 0.01 to 50 g / 10 min. The content of a high molecular weight component having an intrinsic viscosity [η] of 8 to 13 dl / g is 15 to 50% by weight. And the isotactic pentad fraction (mmmm) measured by 13C-NMR is 0.970 or more. 4. The polypropylene resin composition according to claim 3, wherein the crystalline polypropylene further has the following characteristics. Gel permeation chromatography (GPC)
The molecular weight distribution Mw / Mn measured in the above is 6 or more and Mz /
Mw is 4 or more. 5. A mixture of a polysiloxane having at least one Si—H bond in a molecule and a crystalline polypropylene having the following characteristics, or a mixture of the crystalline polypropylene and another polyα-olefin. A polyolefin resin composition obtained by heating and melting a mixture in the presence of an alkali metal or alkaline earth metal alkoxy compound. The melt flow rate (MFR) measured under a load of 2.16 kg at 230 ° C. is 0.01 to 50 g / 10 min. The content of a high molecular weight component having an intrinsic viscosity [η] of 8 to 13 dl / g is 15 to 50% by weight. Isotactic pentad fraction (mmmm) measured by 13C-NMR is 0.970 or more 6. The polypropylene resin composition according to claim 5, wherein the crystalline polypropylene further has the following characteristics. Gel permeation chromatography (GPC)
The molecular weight distribution Mw / Mn measured in the above is 6 or more and Mz /
Mw is 4 or more.