JP2011068819A - Polypropylene-based injection foamed article and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene-based injection formed article that has good moldability, is excellent in uniformity of foaming and in surface appearance, and whose high expansion ratio achieves substantial weight reduction, and to provide a method for producing the same. <P>SOLUTION: The polypropylene-based injection formed article is obtained by injection foaming of a propylene-based resin composition prepared by combining 0.05-10 pts.wt. foaming agent into 100 pts.wt. propylene-based resin component comprised of 6-100 wt.% propylene-based polymer (X) satisfying the requirements (i)-(vi), and 0-94 wt.% propylene-based polymer (Y) that is different from the propylene-based polymer (X) and whose weight average molecular weight is 50,000-800,000. Requirement (i): Melt flow rate (MFR) (temperature of 230°C and loading of 2.16 kg) is ≥0.01 g/10 min and ≤100 g/10 min. Requirement (ii): The ratio (Q value) of weight-average molecular weight (Mw) measured by gel permeation chromatography (GPC) to number-average molecular weight (Mn) is ≥3.5 and ≤10.5. Requirement (iii): The ratio of a component whose molecular weight (M) is at least 2,000,000 to the total amount in the molecular weight distribution curve obtained by GPC is ≥0.4 wt.% and <10 wt.% Requirement (iv): An amount of the component eluted by o-dichlorobenzene (ODCB) at 40°C or below by the temperature raising elution fractionation (TREF) is ≤3.0 wt.%. Requirement (v): isotactic triad fraction (mm fraction) measured by 13C-NMR is ≥95%. Requirement (vi): Strain hardening degree (λ max)upon measuring elongation viscosity is ≥6.0. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polypropylene-based injection-foamed molded article and a method for producing the same, and more specifically, a polypropylene-based foam having good moldability, excellent foam uniformity and surface appearance, and capable of significantly reducing weight at a high foaming ratio. The present invention relates to a molded body and a manufacturing method thereof.

Conventionally, polypropylene resin has good physical properties and moldability, and its use range is rapidly expanding as an environmentally friendly material. In particular, for automobile parts and the like, a lightweight and excellent polypropylene resin product is provided, and one of such products is an injection foam molded product of a polypropylene resin.
So far, in the injection molding of polypropylene resin, so-called injection foam molding has been performed in which foaming is performed for weight reduction, cost reduction, and prevention of warping and sink marks of the molded body. As a technology for highly foaming polypropylene-based resin, a resin containing a foaming agent is injection-molded in a mold space that is held so that the mold can be opened, and then the mold is opened to expand the space. There is a so-called core back method (moving cavity method) for foaming (for example, Patent Document 1).
Ordinary linear polypropylene resins are crystalline and have low melt tension (melt tension), and bubbles are easily destroyed. As a result, appearance defects called silver streaks (or swirl marks) are likely to occur on the surface of the molded body, and voids are likely to be generated inside, making it difficult to increase the expansion ratio. In addition, since the bubbles were non-uniform and large, the resulting molded article was not sufficiently rigid. Note that the void means a coarse bubble generated when internal bubbles communicate with each other, and means a bubble whose diameter substantially exceeds 1.5 mm.
As a method for improving foamability, a method of increasing the melt tension of a polypropylene resin by adding a crosslinking agent or a silane graft thermoplastic resin has been proposed (for example, Patent Document 2 and Patent Document 3). However, in this method, although a foamed molded article having a high expansion ratio can be obtained, the viscosity at the time of melting is excessively increased, and the surface properties of the obtained molded article are also poor.

On the other hand, when used as an automobile part, high rigidity and high impact resistance are often required. As a method for improving the impact resistance, there has been proposed a method in which an amorphous rubber-like substance is added to a polypropylene resin by blending or multistage polymerization (for example, Patent Document 4, Patent Document 5, and Patent Document 6). However, in this method, although the impact resistance is high, the dispersibility of the rubber component to be added is poor and the molding becomes poor, or the foaming property of the resin is not sufficient, and a foamed molded article having a high foaming ratio of 2 times or more is obtained. Couldn't get.
As described above, it has heretofore been difficult to obtain an injection foam molded article having good injection foam moldability, excellent foam uniformity and surface appearance, and capable of drastically reducing weight at a high foaming ratio.

WO2005 / 026255 JP 61-152754 A Japanese Patent Laid-Open No. 7-109372 JP 2001-81251 A JP 2002-11748 A JP 11-309737 A

  An object of the present invention is to provide a polypropylene-based injection-foamed molded article having good moldability, excellent foaming uniformity and surface appearance, and capable of drastically reducing weight at a high foaming ratio, in view of the above-mentioned problems of the prior art. There is to do.

  As a result of intensive studies to solve the above problems, the present inventors have found that a specific propylene polymer having specific physical properties alone, or in addition, other propylene having a specific weight average molecular weight different from that. A propylene resin composition comprising a propylene resin component composed of a polymer and a specific amount of a foaming agent is prepared, and when it is injection-foam molded, the moldability is good, the foaming uniformity, It was found that a polypropylene-based injection-foamed molded article having an excellent surface appearance and capable of being greatly reduced in weight at a high expansion ratio was obtained, and the present invention was completed based on this finding.

That is, according to the first invention of the present invention, the propylene-based polymer (X) satisfying the following requirements (i) to (vi) (hereinafter sometimes simply referred to as “component (X)”). A propylene polymer (Y) having a weight average molecular weight of 50,000 to 800,000, which is 6 to 100% by weight and different from the propylene polymer (X) (hereinafter sometimes simply referred to as “component (Y)”). .) A propylene-based resin composition comprising 0.05 to 10 parts by weight of a foaming agent with respect to 100 parts by weight of a propylene-based resin component consisting of 0 to 94% by weight is formed by injection foam molding. A polypropylene-based injection-foamed molded article is provided.
Requirement (i): Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is 0.01 g / 10 min or more and 100 g / 10 min or less.
Requirement (ii): The ratio (Q value) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 3.5 or more and 10.5 or less.
Requirement (iii): In the molecular weight distribution curve obtained by GPC, the ratio of the component having a molecular weight (M) of 2 million or more to the total amount is 0.4% by weight or more and less than 10% by weight.
Requirement (iv): In temperature rising elution fractionation (TREF) with orthodichlorobenzene (ODCB), the component eluted at a temperature of 40 ° C. or less is 3.0% by weight or less.
Requirement (v): The isotactic triad fraction (mm fraction) measured by 13C-NMR is 95% or more.
Requirement (vi): The strain hardening degree (λmax) in the measurement of elongational viscosity is 6.0 or more.

According to the second invention of the present invention, in the first invention, the propylene-based polymer (X) is a polypropylene-based injection-foamed molded article characterized by further satisfying the following requirement (vii): Provided.
Requirement (vii): ME (memory effect) satisfies the following relational expression.
(ME) ≧ −0.26 × log (MFR) +1.9
[In the formula, ME (memory effect) uses a melt indexer with an orifice of 8.00 mm in length and a diameter of 1.00 mmφ, sets the temperature in the cylinder to 190 ° C., applies a load, and the extrusion speed is 0 At 1 g / min, the polymer extruded from the orifice is quenched in ethanol, and the strand diameter of the extrudate is divided by the orifice diameter. ]

According to the third aspect of the present invention, in the first or second aspect, the propylene polymer (X) further satisfies the following requirement (viii), and is a polypropylene injection foam molding, The body is provided.
Requirement (viii): In the molecular weight distribution curve obtained by GPC, the common logarithm of the molecular weight corresponding to the peak position is Tp, and the common logarithm of the molecular weight at the position where the peak height is 50% is L ₅₀ and H ₅₀ (L ₅₀ Is lower molecular weight than Tp, H ₅₀ is higher molecular weight than Tp), and α and β are defined as α = H ₅₀ −Tp and β = Tp−L ₅₀ , respectively, α / β is larger than 0.9 , Less than 2.0.

  According to a fourth invention of the present invention, in any one of the first to third inventions, the foaming agent is at least one selected from a chemical foaming agent or a physical foaming agent. A system injection foamed molded article is provided.

  Furthermore, according to a fifth invention of the present invention, there is provided a method for producing a polypropylene-based injection foamed molding according to any one of the first to fourth inventions by an injection foaming method, wherein the propylene-based resin composition A polypropylene-based injection-foamed molded article comprising: an injection step of injecting and filling a mold cavity in a molten state or a semi-molten state; and a foaming step of foaming the propylene-based resin composition in the mold cavity A manufacturing method is provided.

  According to a sixth aspect of the present invention, in the fifth aspect, the injection foam molding method comprises a propylene-based resin composition in a molten or semi-molten state in an amount less than the volume of the mold cavity. Provided is a method for producing a polypropylene-based injection-foamed molded article characterized by a short shot method comprising an injection process for injection-filling a mold cavity and a foaming process for filling a void in the mold cavity with an expansion pressure by a foaming agent. Is done.

  According to a seventh aspect of the present invention, in the fifth aspect, the injection foam molding method includes a fixed mold and a movable mold capable of moving forward and backward, and the shape position of the final product. An injection step of injecting and filling a molten or semi-molten propylene resin composition into a mold cavity having a mold cavity clearance (t0) smaller than the mold cavity clearance (t1) corresponding to A polypropylene-based injection foam molding characterized by a mold opening injection molding method comprising a foaming step of retracting a movable mold to a cavity clearance (t1) and filling a void of a mold cavity with an expansion pressure by a foaming agent. A manufacturing method is provided.

  The polypropylene-based injection-foamed molded article of the present invention has a remarkable effect that the moldability is good, the foaming uniformity and the surface appearance are excellent, and the weight can be significantly reduced at a high foaming ratio. It can be suitably used for injection molding parts such as parts.

It is a figure which shows an example of the molecular weight distribution curve in GPC. It is a figure of the description of the base line of a chromatogram in GPC, and an area. It is a figure which shows an example of the molecular weight distribution derived from [A-1] in GPC, and [A-2] origin. It is a plot figure which shows an example of the extensional viscosity measured with the uniaxial extensional viscometer.

The polypropylene-based injection-foamed molded article of the present invention is a propylene-based polymer (X) that satisfies the following requirements (i) to (vi) (hereinafter sometimes simply referred to as “component (X)”) or it. 0.05 to 10 parts by weight of a foaming agent was blended with 100 parts by weight of a propylene-based resin component composed of a propylene-based polymer (Y) (hereinafter sometimes simply referred to as “component (Y)”). The propylene resin composition is obtained by injection foam molding.
Requirement (i): Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is 0.01 to 100 g / 10 min.
Requirement (ii): The ratio (Q value) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 3.5 to 10.5.
Requirement (iii): In the molecular weight distribution curve obtained by GPC, the ratio of the component having a molecular weight (M) of 2 million or more to the total amount is 0.4% by weight or more and less than 10% by weight.
Requirement (iv): In temperature rising elution fractionation (TREF) with orthodichlorobenzene (ODCB), the component eluted at a temperature of 40 ° C. or less is 3.0% by weight or less.
Requirement (v): The isotactic triad fraction (mm fraction) measured by 13C-NMR is 95% or more.
Requirement (vi): The strain hardening degree (λmax) in the measurement of elongational viscosity is 6.0 or more.

Hereinafter, the components of the propylene-based resin composition, the production of the propylene-based resin composition, the polypropylene-based injection-foamed molded article, the production method thereof, and the like are described in detail.
I. Components of propylene-based resin composition 1. Propylene resin component 1-1. Propylene polymer (X)
The propylene-based polymer used in the present invention has the following requirements (i) to (vi), or in addition to these, the properties and properties shown in the requirements (vii) and / or the requirements (viii): Features.
Requirement (i): Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is 0.01 to 100 g / 10 min.
Requirement (ii): The ratio (Q value) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 3.5 to 10.5.
Requirement (iii): In the molecular weight distribution curve obtained by GPC, the ratio of the component having a molecular weight (M) of 2 million or more to the total amount is 0.4% by weight or more and less than 10% by weight.
Requirement (iv): In temperature rising elution fractionation (TREF) with orthodichlorobenzene (ODCB), the component eluted at a temperature of 40 ° C. or less is 3.0% by weight or less.
Requirement (v): The isotactic triad fraction (mm fraction) measured by 13C-NMR is 95% or more.
Requirement (vi): The strain hardening degree (λmax) in the measurement of elongational viscosity is 6.0 or more.
Requirement (vii): ME (memory effect) satisfies the following relational expression.
(ME) ≧ −0.26 × log (MFR) +1.9
[In the formula, ME (memory effect) uses a melt indexer with an orifice of 8.00 mm in length and a diameter of 1.00 mmφ, sets the temperature in the cylinder to 190 ° C., applies a load, and the extrusion speed is 0 At 1 g / min, the polymer extruded from the orifice is quenched in ethanol, and the strand diameter of the extrudate is divided by the orifice diameter. ]
Requirement (viii): In the molecular weight distribution curve obtained by GPC, the common logarithm of the molecular weight corresponding to the peak position is Tp, and the common logarithm of the molecular weight at the position where the peak height is 50% is L ₅₀ and H ₅₀ (L ₅₀ Is lower molecular weight than Tp, H ₅₀ is higher molecular weight than Tp), and α and β are defined as α = H ₅₀ −Tp and β = Tp−L ₅₀ , respectively, α / β is larger than 0.9 , Less than 2.0.
Hereinafter, each item will be described sequentially.

I. Propylene Polymer Structure, Long-Chain Branched Structure Definition and Identification Method The propylene polymer of the present invention has excellent balance between physical properties and melt processability with controlled melt fluidity (melt stretchability) and melt tension. It is a long chain branched propylene polymer.
The propylene-based polymer of the present invention is considered that the melt properties are remarkably improved by introducing the above-mentioned long chain branching.
In general, ¹³ C-NMR is used for directly detecting and quantifying the branched structure and the number of branches. Further, ¹³ C-NMR, GPC-vis, and GPC-malls are used for detection and quantification of the number of branches and branch distribution. However, the above method has a limit of quantification. At present, rheological methods are considered to have the highest sensitivity as a method for evaluating branching. For example, measurement of flow activation energy in linear viscoelasticity measurement and strain hardening degree in elongational viscosity measurement are generally used at this stage as a method for detecting a small amount of branching.
Regarding the branched structure, the present inventors have inferred as follows in consideration of the mechanism and mechanism capable of forming the branched structure.

That is, from the active species derived from the catalyst component [A-1] used in the method for producing a propylene-based polymer, which will be described later, one end of the polymer mainly has a propenyl structure (by a special chain transfer reaction generally called β-methyl elimination). Vinyl structure) and so-called macromers are formed.
The terminal propenyl structure (vinyl structure) terminated by the β-methyl elimination reaction is shown below (reference document: Macromol. Rapid Commun. 2000, 21, 1103-1107).

This macromer can generate a higher molecular weight and is assumed to be incorporated into the active species derived from the catalyst component [A-2] having better copolymerizability, which will be described later, and the macromer copolymerization is proceeding. Yes.
Therefore, the propylene polymer of the present invention has a specific branched structure as shown in the following structural formula (2).
In Structural Formula (2), Ca, Cb, and Cc represent methylene carbon adjacent to the branched carbon, Cbr represents the methine carbon at the root of the branched chain, and P1, P2, and P3 represent propylene-based polymer residues. Indicates.
P1, P2, and P3 may contain a branched carbon (Cbr) different from Cbr described in the structural formula (2) in itself.

Such a branched structure is identified by ¹³ C-NMR analysis. The assignment of each peak is described in Macromolecules, Vol. 35, no. 10. The description of 2002, pages 3839-3842 can be referred to. That is, a total of three methylene carbons (Ca, Cb, Cc) were observed, each at 43.9-44.1 ppm, 44.5-44.7 ppm, and 44.7-44.9 ppm. Methine carbon (Cbr) is observed at ˜31.7 ppm. Hereinafter, the methine carbon observed at 31.5 to 31.7 ppm may be abbreviated as branched carbon (Cbr).
It is characterized in that three methylene carbons adjacent to the branched methine carbon Cbr are observed in three non-equivalent diastereotopics.

The branched chain assigned by ¹³ C-NMR referred to in the present invention represents a propylene polymer residue having 5 or more carbon atoms branched from the main chain of the propylene polymer. It can be distinguished from a branch having 4 or less carbon atoms by the difference in the peak position of the branched carbon (see Macromol. Chem. Phys. 2003, Vol. 204, p. 1738).

In general, considering the definition of the number of branches and the length of the polymer, the higher the number of branches, the better the melt properties. On the other hand, it is considered that if the number of branches is unevenly distributed between the molecules, a gel is generated and the effect of improving the melt properties is reduced.
The number of branches is defined as the number of branches (density) per 1000 total skeleton-forming carbons of the branched carbon (Cbr) observed at 31.5 to 31.7 ppm using the assignment by ¹³ C-NMR. . However, the total skeleton-forming carbon means all carbon atoms other than methyl carbon.

As a result of ¹³ C-NMR measurement, it can be seen that a small amount of a branched component is present in the propylene-based polymer having improved melt properties according to the present invention. The amount is less than the quantification limit of 0.1, but there are 0.01 or more of the detection limit.
On the other hand, if the amount of branching is too large, there is a concern that gel is generated and the appearance of the molded product is impaired. Furthermore, there is a problem of causing deterioration of melt ductility.
Therefore, the number of branches is 0.01 or more as a lower limit and 0.4 or less as an upper limit.
Even when the current ¹³ C-NMR of high magnetic field NMR is used, the limit of quantification is 0.1 or more, and the quantification has not been achieved so far. When the branching was below the limit of quantification by ¹³ C-NMR, instead of this, branching was evaluated by a more sensitive rheological method. As a result, the obtained strain hardening degree (λmax) is defined to be 6.0 or more.

Moreover, in order to show high strain hardening like the propylene-type polymer of this invention, regarding the branch length, it is thought that 7000 or more which is an entanglement molecular weight of polypropylene is required (reference: Macromolecules. 1998, 31, 1335, Macromolecules). 2002, 35, 10062).
This corresponds to about 400 or more in terms of the number of skeleton carbon atoms. As used herein, skeletal carbon means all carbon atoms other than methyl carbon. As the branch length becomes longer, the melt physical properties are considered to be further improved.
Therefore, the branched chain length of the propylene-based polymer of the present invention is skeleton carbon number 500 (polypropylene molecular weight conversion: 11,000) or more, preferably skeleton carbon number 1000 (polypropylene molecular weight conversion: 21,000) or more. More preferably, it has 2000 or more skeleton carbon atoms (polypropylene molecular weight conversion: 42,000).

The polypropylene molecular weight converted value here is strictly different from the molecular weight value measured by GPC, but approximates the number average molecular weight (Mn) measured by GPC.
Therefore, the branch length of the propylene-based polymer of the present invention is 11,000 or more, preferably 21,000 or more, more preferably 42,000 or more in terms of number average molecular weight (Mn) measured by GPC, Replaced.

Further, when considering the polymerization mechanism, the macromer generated from the active species derived from the catalyst component [A-1] is incorporated into the main chain to form a branched structure, so that the average molecular weight of the macromer is that of the incorporated branched chain. Characterized as average molecular weight.
For example, in the propylene-based polymer of the present invention, when the molecular weight of the macromer generated from the active species derived from [A-1] is 50,000 in the number average molecular weight, the average molecular weight of the incorporated branched chain is 50,000, Converted to skeleton carbon, it is interpreted as 2400.
The number average molecular weight of the macromer generated from the active species derived from the above [A-1] is based on the molecular weight when the polymerization is carried out by the peak top of the portion derived from [A-1] in GPC or [A-1] alone. Can be estimated.

On the other hand, the branched distribution of the polymer can be measured by GPC-vis or GPC-malls, but considering the polymerization mechanism, the macromer derived from [A-1] has a higher molecular weight and higher copolymerization. Considered that long chain branching has been introduced into the molecular weight component derived from [A-2] because it is considered that branching is generated by incorporation into the active species derived from component [A-2]. ing.
Since the molecular weight component derived from the catalyst component [A-2] has a higher molecular weight than the molecular weight component derived from [A-1], the branched distribution has a high molecular weight side ([A-2] derived side). In addition, it is considered that the distribution form is introduced with branching.
In addition, the molecular weight component derived from [A-1] has a branched structure formed by incorporating the macromer by [A-1] itself.
An example of the molecular weight distribution derived from [A-1] and [A-2] is shown in FIG.

Describing the relationship between the number of branches and the distribution of branches, in order to improve the melt physical properties, it is generally considered that a large number of branches is necessary, and in Patent Document 9 (Japanese Patent Laid-Open No. 2007-154121), A propylene homopolymer having a branch number of 0.1 / 1000 skeleton carbon or more is disclosed.
However, the strain hardening degree (λmax) in the measurement of the extensional viscosity of the disclosed propylene homopolymer is less than 6, and the strain hardening degree (λmax) in the measurement of the extensional viscosity of the propylene polymer of the present invention is 6. The improvement effect is not sufficient even when compared with 0 or more. This is because the desired branching component is not sufficiently introduced because it is produced from a single complex, meaning that the effect of improving the melt properties is small even if the number of branches is simply large on average.
The propylene-based polymer of the present invention does not necessarily have a large number of branches (average value) as compared with conventional branched polymers, but by introducing multiple branches into the high molecular weight side by combining a plurality of complexes. The melt properties are remarkably improved.

Further, the stereoregularity of the side chain will be described. The stereoregularity of the main chain and the side chain is determined by the stereoregular ability of [A-1] and [A-2] used, respectively. If the stereoregularity of the side chain is low, even if the crystallinity of the main chain is high, the overall crystallinity is degraded. Therefore, in order to obtain a higher-rigidity polymer, it is preferable that the side chain and the main chain have high stereoregularity. As the value, both the main chain and the side chain are 95% or more in mm fraction. Especially preferably, it is 96% or more, More preferably, it is 97% or more.
The stereoregularity of the side chain is considered to be equal to the stereoregularity of the polymer by [A-1] alone.
The details of the stereoregularity of the main chain and side chain will be described later.

II. Physical Properties of Propylene Polymer The propylene polymer of the present invention is excellent in the balance between physical properties and melt processability with controlled melt fluidity (melt spreadability) and melt tension. The physical properties of the propylene polymer of the present invention will be described.
1. Melt flow rate (MFR)
As shown in the requirement (i), the propylene polymer of the present invention has a melt flow rate (MFR) measured at a temperature of 230 ° C. and a load of 2.16 Kg of 0.01 g / 10 min or more and 100 g / 10 min or less. Need to be.
MFR is an indicator of fluidity, and this value decreases as the molecular weight of the polymer increases, while this value increases as the molecular weight decreases. When this value is small, fluidity is deteriorated and melt spreadability is deteriorated. Accordingly, the MFR needs to be 0.01 g / 10 min or more, preferably 0.1 g / 10 min or more, and more preferably 0.3 g / 10 min or more.
On the other hand, when this value is large, the fluidity is improved, but the molecular weight is too small, which causes a deterioration in mechanical properties such that the impact strength is lowered when formed into a molded body. Accordingly, the MFR is required to be 100 g / 10 min or less, preferably 20 g / 10 min or less, more preferably 10 g / 10 min or less.

The melt flow rate (MFR) is a test condition in accordance with JIS K6921-2 “Plastics—Polypropylene (PP) molding and extrusion materials—Part 2: How to make test pieces and properties”. : A value measured at 230 ° C. and a load of 2.16 kgf.
The melt flow rate (MFR) of the propylene polymer can be easily adjusted by changing the temperature and pressure conditions of propylene polymerization, or by adding a chain transfer agent such as hydrogen during polymerization as the most general technique. Can be done.

2. Average molecular weight and molecular weight distribution (Mw, Mn, Q value) measured by GPC
As shown in the requirement (ii) above, the propylene-based polymer of the present invention is a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography (GPC), Mw / Mn (Q Value) in the range of 3.5 or more and 10.5 or less.
The Q value is an index representing the spread of the molecular weight distribution, and the larger the value, the wider the molecular weight distribution. If the Q value is too small, the distribution is narrow, and the balance between melt spreadability and workability becomes poor. Accordingly, the Q value needs to be 3.5 or more, preferably 4.0 or more. More preferably, it is 4.5 or more. On the other hand, if the Q value is too large, the amount of unnecessary (low) molecular weight components increases, which may deteriorate the melt ductility. Therefore, the Q value needs to be 10.5 or less, preferably less than 8.0, and more preferably less than 7.5.
The average molecular weight and molecular weight distribution (Mw, Mn, Q value) measured by GPC of the propylene polymer can be changed by changing the temperature and pressure conditions of propylene polymerization, or the most common method is chain transfer such as hydrogen Adjustment can be easily made by a method of adding an agent during propylene polymerization. Furthermore, when using 2 or more types of the metallocene complex to be used, it can control by changing the quantity ratio.

3. Bias of molecular weight distribution obtained from molecular weight distribution curve by GPC toward high molecular weight side As shown in the above requirement (viii), the propylene polymer of the present invention has a peak position in the molecular weight distribution curve obtained by GPC. The common logarithm of the corresponding molecular weight is Tp, and the common logarithm of the molecular weight at the position where the peak height is 50% is L ₅₀ and H ₅₀ (L ₅₀ is lower molecular weight side than Tp, H ₅₀ is higher molecular weight side than Tp) , Α and β are defined as α = H ₅₀ −Tp and β = Tp−L ₅₀ , respectively, it is desirable that α / β is greater than 0.9 and less than 2.0. Here, α / β is an index representing the deviation of the molecular weight distribution toward the high molecular weight side.
The spread of the molecular weight distribution is indicated by a molecular weight distribution curve obtained by GPC. That is, a graph is created in which the common logarithm of molecular weight (MW) is plotted on the horizontal axis and the relative differential mass of the molecule corresponding to the MW is plotted on the vertical axis.
The molecular weight (MW) referred to here is the molecular weight of individual molecules constituting the propylene polymer, and is different from the weight average molecular weight (Mw) of the propylene polymer. FIG. 1 is a diagram showing an example of a molecular weight distribution curve. Α and β are obtained from the created graph. In the present invention, as described above, it is desirable that α / β is greater than 0.9 and less than 2.0.

Usually, when uniform polymerization is carried out with a catalyst having a single active site, the molecular weight distribution has the most probable distribution shape. The most probable distribution α / β is calculated as 0.9.
Therefore, the molecular weight distribution of the propylene-based polymer of the present invention means that the molecular weight distribution of the propylene-based polymer that is uniformly polymerized at a single active site is further widened to the higher molecular weight side.
When α / β is 0.9 or less, the amount of the high molecular weight component is relatively insufficient, so that the melt tension and swell ratio become small, and the moldability deteriorates.
Therefore, it is desirable that the propylene-based polymer of the present invention has α / β larger than 0.9, preferably 1.0 or more, and more preferably 1.1 or more.

On the other hand, when α / β is 2.0 or more, the amount of the high molecular weight component is too large, which causes deterioration of melt ductility.
Therefore, the propylene-based polymer of the present invention desirably has an α / β of less than 2.0, preferably less than 1.8, more preferably less than 1.7, and still more preferably less than 1.6. It is.
In the molecular weight distribution curve, two or more peaks may appear. In that case, the maximum peak can be replaced with the peak of the present invention. Moreover, when two or more H50 appears, it can replace with the molecular weight of the highest molecular weight side. Similarly, when two or more L50s appear, the molecular weight on the lowest molecular weight side can be replaced.
The bias toward the high molecular weight side of the molecular weight distribution obtained from the GPC molecular weight distribution curve of the propylene-based polymer is based on selecting one that can produce a high molecular weight polymer as one of the two types of metallocene complexes used. Adjustment can be easily made by controlling the amount of hydrogen added during the polymerization. It can also be adjusted by changing the amount ratio of the two metallocene complexes used.

4). Ratio of components having a molecular weight (M) of 2 million or more in the molecular weight distribution curve by GPC As shown in the requirement (iii), the propylene-based polymer of the present invention has a molecular weight distribution curve obtained by GPC. On the other hand, the ratio (W (2 million or more)) of components having a molecular weight (M) of 2 million or more is 0.4% by weight or more and less than 10% by weight.
The ratio of 2 million or more (W (2 million or more)) is an index indicating the ratio of a very high molecular weight component contained in the polymer.
The very high molecular weight component ratio W (2 million or more) is an integral molecular weight distribution curve obtained by GPC (the total amount is normalized to 1), and the molecular weight (M) is 2 million (Log (M) = 6). .3) The integral value up to the following is defined as a value obtained by subtracting from 1. An example of the integrated molecular weight distribution curve is also shown in FIG.

As described above, when the amount of the high molecular weight component is insufficient, the melt tension and the swell ratio are decreased, and the moldability is deteriorated. Therefore, a component having a high molecular weight is necessary, and the moldability is efficiently improved by containing a small amount of a component having a very high molecular weight. This very high molecular weight component is considered to contain a branched component as described above.
Therefore, the propylene-based polymer of the present invention desirably has W (2 million or more) of 0.4% by weight or more, preferably 1.0% by weight or more, more preferably 1.5%. % By weight or more.
However, if the ratio of this component is too high, the fluidity is deteriorated. In addition, since it is a component having a very high molecular weight, a gel is generated, resulting in a problem that the appearance of the molded product is impaired. Moreover, when the ratio of this component is too high, it will cause deterioration of melt ductility.
Therefore, the propylene polymer of the present invention desirably has W (2 million or more) less than 10% by weight, preferably less than 6.0% by weight, and more preferably less than 5% by weight.
In addition, the ratio of the component having a molecular weight (M) of 2 million or more in the molecular weight distribution curve by GPC of the propylene polymer is selected on the low molecular weight side after selecting a metallocene complex that can produce a high molecular weight polymer. Can be easily adjusted by controlling the ratio of the amount of the metallocene complex to the metallocene complex, the amount of hydrogen added during propylene polymerization, and the polymerization temperature.

  So far, adjustment methods related to the molecular weight of the propylene-based polymer such as the ratio of components having MFR, Q value, α / β and molecular weight (M) of 2 million or more have been described. For example, control of the amount of hydrogen can be given as a common control method. When the amount of hydrogen is increased, the MFR of the propylene polymer increases, and the ratio of components having a Q value, α / β, and molecular weight (M) of 2 million or more tends to decrease. On the other hand, it is possible to increase MFR by increasing the polymerization temperature or decreasing the monomer partial pressure. In this case, the ratio of components having a molecular weight (M) of 2 million or more decreases, but the Q value and α / β is not significantly affected. In addition, the ratio of components having a molecular weight (M) of 2 million or more with respect to MFR can be controlled by changing the amount and type of the metallocene complex that produces the high molecular weight side. In this way, the regulation can be controlled by changing the catalyst used and the polymerization conditions.

  The weight average molecular weight (Mw), Q value, α / β, and W (over 2 million) values defined above are all obtained by gel permeation chromatography (GPC). Details of the measuring method and measuring equipment are as follows.

Apparatus: GPC manufactured by Waters (ALC / GPC, 150C)
Detector: MIRAN, 1A, IR detector manufactured by FOXBORO (measurement wavelength: 3.42 μm)
Column: AD806M / S (3 pieces) manufactured by Showa Denko KK
Mobile phase solvent: o-dichlorobenzene (ODCB)
Measurement temperature: 140 ° C
Flow rate: 1.0 ml / min Injection volume: 0.2 ml

The sample is prepared by preparing a 1 mg / mL solution using ODCB (containing 0.5 mg / mL BHT) and dissolving it at 140 ° C. for about 1 hour.
The baseline and interval of the obtained chromatogram are performed as shown in FIG.
In addition, the conversion from the retention capacity obtained by GPC measurement to the molecular weight is performed using a standard curve prepared in advance by standard polystyrene. The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
Brand: F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
Inject 0.2 mL of a solution dissolved in ODCB (containing 0.5 mg / mL BHT) so that each is 0.5 mg / mL to create a calibration curve. The calibration curve uses a cubic equation obtained by approximation by the least square method.
The following numerical value is used for the viscosity formula: [η] = K × Mα used for conversion to molecular weight.
PS: K = 1.38 × 10 −4, α = 0.7
PP: K = 1.03 × 10 −4, α = 0.78

5). Elevated temperature elution fractionation with orthodichlorobenzene (ODCB) (TREF)
As shown in the above requirement (iv), for example, the propylene homopolymer is eluted at a temperature of 40 ° C. or lower in an elution curve obtained by temperature rising elution fractionation (TREF) measurement. The component is 3.0% by weight or less.
A component that elutes at a temperature of 40 ° C. or lower is a low crystalline component. If the amount of this component is large, the crystallinity of the entire product is lowered, and the mechanical strength such as the rigidity of the product is lowered.
Therefore, this amount needs to be 3.0% by weight or less, preferably 2.0% by weight or less, more preferably 1.0% by weight or less, and particularly preferably 0.5% by weight or less. .
Elevated temperature elution fractionation (TREF) of propylene-based polymer with orthodichlorobenzene (ODCB) can generally be kept low by using a metallocene complex, but the purity of the catalyst should be kept above a certain level. In addition, it is necessary that the catalyst production method and the reaction conditions during the polymerization are not extremely high, and that the amount ratio of the organic aluminum to the metallocene complex is not increased too much.

The details of the measurement method of the eluted component by temperature rising elution fractionation (TREF) are as follows.
A sample is dissolved in orthodichlorobenzene at 140 ° C. to obtain a solution. This is introduced into a TREF column at 140 ° C., cooled to 100 ° C. at a temperature lowering rate of 8 ° C./min, subsequently cooled to 40 ° C. at a temperature lowering rate of 4 ° C./min, and held for 10 minutes. Thereafter, orthodichlorobenzene as a solvent is allowed to flow through the column at a flow rate of 1 mL / min, and the components dissolved in the orthodichlorobenzene at 40 ° C. are eluted in the TREF column for 10 minutes, and then the heating rate is 100 ° C./hour. The column is linearly heated to 140 ° C. to obtain an elution curve.

Column size: 4.3mmφ × 150mm
Column packing material: 100 μm surface inert treatment glass beads Solvent: Orthodichlorobenzene Sample concentration: 5 mg / mL
Sample injection volume: 0.1 mL
Solvent flow rate: 1 mL / min Detector: Fixed wavelength infrared detector, manufactured by FOXBORO, MIRAN, 1A
Measurement wavelength: 3.42 μm

6). Isotactic triad fraction (mm) measured by ¹³ C-NMR
As shown in the requirement (v), the propylene-based polymer of the present invention has a stereoregularity in which the mm fraction of the three propylene unit chains obtained by ¹³ C-NMR is 95% or more.
The mm fraction is a ratio of three propylene unit chains in which the direction of methyl branching in each propylene unit is the same among arbitrary three propylene unit chains composed of head-to-tail bonds in the polymer chain. This mm fraction is a value indicating that the steric structure of the methyl group in the polypropylene molecular chain is controlled isotactically, and the higher the value, the higher the degree of control.
If the mm fraction is smaller than this value, the mechanical properties such as the elastic modulus of the product are lowered. Therefore, the mm fraction is preferably 96% or more, and more preferably 97% or more.
Further, the stereoregularity of the main chain and the side chain is determined by the stereoregular ability of the catalyst components [A-1] and [A-2] used in the method for producing a propylene polymer described later. If the stereoregularity of the side chain is low, even if the crystallinity of the main chain is high, the overall crystallinity is degraded. Therefore, in order to obtain a higher rigidity polymer, it is preferable that the side chain and the main chain have high stereoregularity.
As the value, the main chain and the side chain are 95% or more in mm fraction. Especially preferably, it is 96% or more, More preferably, it is 97% or more.
The isotactic triad fraction (mm) measured by ¹³ C-NMR of the propylene polymer can be easily adjusted by the selection of the metallocene complex to be used and the polymerization temperature.

The detail of the measuring method of mm fraction of the propylene unit 3 chain | strand by ¹³ C-NMR is as follows.
A sample of 375 mg was completely dissolved in 2.5 ml of deuterated 1,1,2,2, -tetrachloroethane in an NMR sample tube (10φ), and then measured at 125 ° C. by a proton complete decoupling method. The chemical shift was set to 74.2 ppm at the center of the three peaks of deuterated 1,1,2,2-tetrachloroethane. The chemical shift of other carbon peaks is based on this.
Flip angle: 90 degrees Pulse interval: 10 seconds Resonance frequency: 100 MHz or more Integration frequency: 10,000 times or more Observation range: -20 ppm to 179 ppm
Number of data points: 32768

The mm fraction is measured using a ¹³ C-NMR spectrum measured under the above conditions.
Spectral assignments were made with reference to Macromolecules, (1975) 8６８, 687 and Polymer, 30: 1350 (1989).

A more specific method for determining the mm fraction will be described below.
Peaks derived from the methyl group of the three-chain central propylene bonded head-to-tail around the propylene unit occur in three regions depending on the configuration.
mm: about 24.3 to about 21.1 ppm
mr: about 21.2 to about 20.5 ppm
rr: about 20.5 to about 19.8 ppm
The chemical shift range of each region slightly shifts depending on the molecular weight and copolymer composition, but the above three regions can be easily identified.
Here, mm, mr, and rr are each represented by the following structure.

The mm fraction is calculated from the following mathematical formula (I).
mm fraction = peak area of mm area / (peak area of mm area + peak area of mr area + peak area of rr area) × 100 [%] (I)

  Moreover, the propylene polymer of the present invention may have the following partial structure containing an ethylene unit.

The methyl group (PPE-methyl group) of the central propylene unit of the partial structure PPE resonates in the mr region around 20.9 ppm, and the methyl group (EPE-methyl group) of the central propylene unit of the partial structure EPE is 20.2 ppm. Since resonance occurs in the vicinity of the rr region, in the case of having such a partial structure, it is necessary to reduce the peak areas based on the PPE-methyl group and the EPE-methyl group from the peak areas of both the mr and rr regions. The peak area based on the PPE-methyl group can be evaluated by the peak area of the corresponding methine group (resonance around 31.0 ppm).
-The peak area based on a methyl group can be evaluated by the peak area of the corresponding methine group (resonance at around 33.3 ppm).

  Moreover, as a partial structure containing a position irregular unit, it may have the following structure (5-a), structure (5-b), structure (5-c), and structure (5-d).

Among them, the carbon A, A ′, A ″ peaks appear in the mr region, and the carbon B, B ′ peaks appear in the rr region. Further, the carbon C, C ′ peaks appear in 16.8 to 17.8 ppm. .
Therefore, when the mm fraction is calculated in the formula (I), the carbon appearing in the mr and rr regions with the peak not based on the head-to-tail three-linked chain from the peak area of the mr region and the peak area of the rr region, respectively. It is necessary to reduce the peak areas based on A, A ′, A ″, B, and B ′.

The peak areas based on carbon A are carbon D (resonance around 42.4 ppm), carbon E and G (resonance around 36.0 ppm) and carbon F (38 in the position irregular substructure [structure (5-a)]). It can be evaluated from 1/4 of the sum of the peak areas of resonance at around .7 ppm.
The peak areas based on carbon A ′ are carbon H and I (resonance around 34.7 ppm and around 35.0 ppm) and carbon J of the position irregular substructure [structure (5-b) and structure (5-c)]. It can be evaluated by 2/5 of the sum of peak areas (resonance around 34.1 ppm) and the sum of peak areas of carbon K (resonance around 33.7 ppm).
The peak area based on the carbon A ″ can be evaluated by the sum of the peak areas of the carbon L (resonance in the vicinity of 27.7 ppm) of the position irregular partial structure [structure (5-d)].
The peak area based on carbon B can be evaluated by carbon J. The peak area based on carbon B ′ can be evaluated by carbon K.
Note that the positions of the carbon C peak and the carbon C ′ peak need not be considered because they are not related to the focused mm, mr, and rr regions.
As described above, since the peak areas of mm, mr, and rr can be evaluated, the mm fraction of the triple chain portion composed of the head-to-tail bond with the propylene unit as the center can be obtained according to the above formula (I).

7). Strain hardening degree (λmax) in measurement of elongational viscosity
As shown in the requirement (vi), the propylene-based polymer of the present invention needs to have a strain hardening degree (λmax) of 6.0 or more in the measurement of elongational viscosity.
The strain hardening degree (λmax) is an index representing the strength at the time of melting, and when this value is large, there is an effect of improving the melt tension. As a result, it is difficult for bubbles to break during foam molding.
Accordingly, the strain hardening degree is required to be 6.0 or more, preferably 10.0 or more, more preferably 12.0 or more, and further preferably 15.0 or more.
The strain hardening degree is an index representing the nonlinearity of elongational viscosity, and it is usually said that this value increases as the molecular entanglement increases. Molecular entanglement is affected by the amount of branching and the length of the branched chain.
Therefore, the greater the amount of branching and the length of branching, the greater the strain hardening degree.
At the present time, it is considered to be the most sensitive method for evaluating branching. Since the branched structure cannot be directly evaluated by ¹³ C-NMR, the strain hardening degree is used as an index of branching instead of the method. It was.

Generally, in order to show a high degree of strain hardening, a branching length of 7,000 or more, which is an entanglement molecular weight of polypropylene, is required. When converted into skeleton carbon number, it corresponds to about 400 or more. As used herein, skeletal carbon means all carbon atoms other than methyl carbon. As the branch length becomes longer, the melt physical properties are considered to be further improved. In particular, when a longer branched chain is introduced, strain hardening is considered to be detected even in a slower strain rate region in the measurement of elongational viscosity.
Therefore, as described above, the branched chain length of the propylene-based polymer of the present invention is not less than 500 skeletal carbons (polypropylene molecular weight conversion: 11,000), preferably 1000 skeletal carbon numbers (polypropylene molecular weight conversion: 2. 10,000) or more, and more preferably 2000 or more skeleton carbon atoms (polypropylene molecular weight conversion: 42,000).
As described above, the polypropylene molecular weight converted value here is strictly different from the molecular weight value measured by GPC, but approximates the number average molecular weight (Mn) measured by GPC.
Therefore, the branch length of the propylene-based polymer of the present invention is 11,000 or more, preferably 21,000 or more, more preferably 42,000 or more in terms of number average molecular weight (Mn) measured by GPC, Can be replaced. The strain hardening degree (λmax) in the measurement of the extensional viscosity of the propylene polymer is 6 or more by controlling the selection of two kinds of metallocene complexes constituting the catalyst used for propylene polymerization, the amount ratio thereof, and the prepolymerization conditions. It can be enlarged. That is, one of the two types of metallocene complexes is selected so as to easily generate a macromer, and the other is selected so that the macromer can be easily incorporated into the polymer and can generate a high molecular weight polymer. Furthermore, by performing prepolymerization, long chain branches are uniformly distributed among the polymer particles.

  Here, regarding the method for measuring the strain hardening degree, the same value can be obtained in principle by any method as long as the uniaxial extensional viscosity can be measured. For example, the details of the measuring method and measuring instrument are disclosed in Polymer 42. Although there are methods described in (2001) 8663, examples of preferable measuring methods and measuring instruments include the following.

Measuring method 1:
Apparatus: Ales manufactured by Rheometrics
Jig: EXTENSIONAL VISUALITY FIXTURE, manufactured by TA Instruments
Measurement temperature: 180 ° C
Strain rate: 0.1 / sec
Preparation of test piece: A sheet of 18 mm × 10 mm and a thickness of 0.7 mm is formed by press molding.

Measurement method 2:
Apparatus: Toyo Seiki Co., Ltd., Melten Rheometer
Measurement temperature: 180 ° C
Strain rate: 0.1 / sec
Preparation of test piece: An extruded strand is prepared at a speed of 10 to 50 mm / min using an orifice having an inner diameter of 3 mm at 180 ° C. using a capillograph manufactured by Toyo Seiki Co., Ltd.

Calculation method:
The elongational viscosity at a strain rate of 0.1 / sec is plotted as a log-log graph of time t (seconds) on the horizontal axis and elongational viscosity ηE (Pa · seconds) on the vertical axis. On the logarithmic graph, the viscosity immediately before strain hardening is approximated by a straight line, the maximum value (ηmax) of the extensional viscosity ηE until the amount of strain reaches 4.0 is obtained, and on the approximate straight line up to that time Let ηlin be the viscosity.
FIG. 4 is an example of a plot of elongational viscosity. ηmax / ηlin is defined as λmax and is used as an index of strain hardening degree.
The strain rate can be measured in the range of 0.001 / sec to 10.0 / sec, and the strain hardening degree varies depending on the difference in strain rate. The strain rate dependency of the strain hardening degree is considered to change depending on the form and length of the introduced branch.

8). Memory effect (ME)
As for the propylene-type polymer of this invention, as shown to said requirement (vii), it is desirable that a memory effect (ME) satisfy | fills the following relational expression (I-1).
(ME) ≧ −0.26 × log (MFR) +1.9 (I-1)
[In the formula, ME (memory effect) uses a melt indexer with an orifice of 8.00 mm in length and a diameter of 1.00 mmφ, sets the temperature in the cylinder to 190 ° C., applies a load, and the extrusion speed is 0 At 1 g / min, the polymer extruded from the orifice is quenched in ethanol, and the strand diameter of the extrudate is divided by the orifice diameter. ]

In the propylene-based polymer of the present invention, preferably, a correlation between a memory effect (ME) that is an index that represents an abundance ratio of a high molecular weight component in a polymer and an MFR that is an index that represents an average molecular weight of the polymer is a specific relationship ( It is characterized by being in the above formula (I-1)).
ME is an index representing the non-Newtonian property of a polymer, and a large ME indicates that a component having a long relaxation time exists in the polymer. That is, when ME is large with the same MFR, it means that a longer-term relaxation component is distributed in the polymer.
Further, it is empirically known that ME has a first-order correlation with Log (MFR), and generally, the larger the molecular weight (that is, the smaller the MFR value), the larger the ME value. .

The propylene-based polymer of the present invention is characterized in that the ME in the MFR match is larger than that of conventionally known polymers as shown in FIG. 5 due to the presence of a branching component in the polymer chain. When the amount of the long-term relaxation component is large, the melt tension is excellent. More preferably, the following relational expression (I-2) is satisfied.
(ME) ≧ −0.26 × log (MFR) +2.20 (I-2)
More preferably, the following relational expression (I-3) is satisfied.
(ME) ≧ −0.26 × log (MFR) +2.40 (I-3)

  The memory effect (ME) was measured using a melt indexer manufactured by Takara, and extruded at 190 ° C. with an orifice diameter of 1.0 mm and length of 8.0 mm under a load. The extrusion speed was 0.1 g. At the time of / min, the polymer extruded from the orifice is quenched in ethanol, and the value of the strand diameter at that time is divided by the orifice diameter.

9. Melt tension and melt spreadability Since the propylene-based polymer of the present invention has a controlled branch structure (branch amount, branch length, branch distribution), melt properties are remarkably improved. That is, it has excellent melt spreadability while having high melt tension. As an index of melt tension and melt spreadability, it can be expressed by a balance between melt tension (MT) and maximum winding speed (MaxDraw) measured by the following measurement method.

A method for measuring the melt tension (MT) and the maximum winding speed (MaxDraw) will be described.
Using a Capillograph 1B manufactured by Toyo Seiki Co., Ltd., the tension detected by the pulley when the resin is extruded in a string shape under the following conditions and wound on a roller is defined as a melt tension (MT).
Capillary: 2.1mm in diameter
Cylinder diameter: 9.6mm
Cylinder extrusion speed: 10 mm / min Winding speed: 4.0 m / min Temperature: 230 ° C.

When the winding speed is gradually increased from 4.0 m / min (acceleration: 5.4 cm / s2), the winding speed immediately before the string-like material is cut is set as the maximum winding speed (MaxDraw). .
Here, a larger MT value means higher melt tension, and a larger MaxDraw means better fluidity and spreadability.
The propylene-based polymer of the present invention has improved melt tension by broadening the molecular weight distribution and introducing branching. Therefore, MT is 5 g or more, preferably 10 g or more, more preferably 15 g or more. .

In addition, as described above, when the high molecular weight component is increased or the number of branches is increased, the MT value can be increased, but conversely, the polymer has too many high molecular weight components or the branches are unevenly distributed. Then, the viscosity becomes too high during winding, causing breakage of the string-like material, and MaxDraw does not increase. That is, the melt ductility is deteriorated.
The propylene-based polymer of the present invention can have a large MaxDraw while maintaining a high MT by controlling the branching component, and the balance between melt tension and melt spreadability is improved.
Therefore, the propylene polymer of the present invention has a MaxDraw of 10 m / min or more, preferably 20 m / min or more, and more preferably 30 m / min or more.

As explained above, the propylene-based polymer of the present invention is a long-chain branched type in which melt spreadability and melt tension are controlled and excellent in balance between physical properties and processability. In contrast to conventional propylene polymers, for example, as described above, Patent Document 9 (Japanese Patent Laid-Open No. 2007-154121) discloses a propylene homopolymer having a branch number of 0.1 / 1000 skeleton carbon or more. However, the degree of strain hardening (λmax) in the measurement of the extensional viscosity is less than 6, and the degree of strain hardening (λmax) in the measurement of the extensional viscosity of the propylene-based polymer of the present invention is 6.0 or more, The effect of improving melt properties is not sufficient. In addition, in the commercial product of polypropylene that is crosslinked by electron beam irradiation and has a high degree of long-chain branching (base melt high melt tension polypropylene, “PF814”), the branched carbon of the structural formula (2) described above is not detected. In addition, the isotactic triad fraction (mm) by ¹³ C-NMR is low (92.5%), and further, molecular cleavage occurs simultaneously with crosslinking during irradiation with an electron beam, resulting in an increase in low molecular weight components. . In addition, as another general method for controlling the molding process characteristics, control is performed by expanding the molecular weight distribution. However, when the molecular weight distribution is expanded, the low molecular weight component is increased as a result. It is thought that stability (return property) is reduced.
However, the propylene-based polymer of the present invention is controlled by expanding the molecular weight distribution by broadening the molecular weight distribution and introducing branches, but the low molecular weight component does not increase and the high molecular weight component increases. Therefore, the above disadvantages do not occur.
Thus, since the propylene-based polymer of the present invention is a long-chain branched type, it has an excellent balance between physical properties and workability with controlled melt ductility and melt tension not found in conventional propylene-based polymers. It has become.

III. Propylene Polymer Production Method About the method of producing the propylene polymer of the present invention, the above-described melt ductility and melt tension, which are the characteristics of the present invention, are controlled and the long chain branching is excellent in balance between physical properties and processability. The method is not particularly limited as long as it is a method for obtaining a propylene-based polymer of the type, and examples of the method for introducing a controlled branched component include the following methods using a plurality of complexes.
That is, a method for producing the long-chain branched propylene polymer, wherein the following catalyst components (A), (B) and (C) are used as propylene polymerization catalysts: The manufacturing method of a polymer is mentioned.
Catalyst component (A): from component [A-1] which is a compound represented by the following general formula (a1) and from component [A-2] which is a compound represented by the general formula (a2) At least one, two or more selected Group 4 transition metal compounds of the periodic table Component [A-1]: Compound represented by general formula (a1) Component [A-2]: Represented by general formula (a2) Compound Catalyst Component (B): Ion Exchange Layered Silicate Catalyst Component (C): Organoaluminum Compound

Hereinafter, the catalyst components (A), (B), and (C) will be described in detail.
(1) Catalyst component (A)
(I) Component [A-1]: Compound represented by general formula (a1)

[In General Formula (a1), each of R ¹¹ and R ¹² independently represents a heterocyclic group containing nitrogen, oxygen, or sulfur having 4 to 16 carbon atoms. In addition, each of R ¹³ and R ¹⁴ is independently halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a C 6-16 aryl that may contain a plurality of hetero elements selected from these Represents a heterocyclic group containing a group, nitrogen or oxygen having 6 to 16 carbon atoms, and sulfur. X ¹¹ and Y ¹¹ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 20 carbon atoms, or a halogenated group having 1 to 20 carbon atoms. Represents a hydrocarbon group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group or a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, Q ¹¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms, It represents a silylene group or a germylene group which may have a hydrocarbon group having 1 to 20 carbon atoms. ]

The heterocyclic group containing nitrogen, oxygen or sulfur having 4 to 16 carbon atoms of R ¹¹ and R ¹² is preferably a 2-furyl group, a substituted 2-furyl group, a substituted 2-thienyl group, or a substituted group. 2-furfuryl group, more preferably a substituted 2-furyl group.
Moreover, as a substituted 2-furyl group, a substituted 2-thienyl group, and a substituted 2-furfuryl group, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, and a propyl group, Examples thereof include halogen atoms such as fluorine atom and chlorine atom, alkoxy groups having 1 to 6 carbon atoms such as methoxy group and ethoxy group, and trialkylsilyl groups. Of these, a methyl group and a trimethylsilyl group are preferable, and a methyl group is particularly preferable.
Further, R ¹¹ and R ¹² are particularly preferably a 2- (5-methyl) -furyl group. R ¹¹ and R ¹² are preferably the same as each other.

Carbon atoms 6 to 16 of the R ¹³ and R ^14, halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or, as the aryl group which may contain a plurality of hetero elements selected from these, In the range of 6 to 16 carbon atoms, on the aryl cyclic skeleton, one or more hydrocarbon groups having 1 to 6 carbon atoms, silicon-containing hydrocarbon groups having 1 to 6 carbon atoms, halogens having 1 to 6 carbon atoms You may have a containing hydrocarbon group as a substituent.
At least one of R ¹³ and R ¹⁴ is preferably a phenyl group, a 4-tbutylphenyl group, a 2,3-dimethylphenyl group, a 3,5-ditbutylphenyl group, a 4-phenyl-phenyl group, or a chlorophenyl. Group, naphthyl group or phenanthryl group, more preferably phenyl group, 4-tbutylphenyl group and 4-chlorophenyl group. R ¹³ and R ¹⁴ are preferably the same as each other.

In the general formula (a1), X ¹¹ and Y ¹¹ are auxiliary ligands and react with the cocatalyst of the component (B) to generate an active metallocene having an olefin polymerization ability. Therefore, as long as this purpose is achieved, X ¹ and Y ¹ are not limited to the type of ligand, and each independently represents hydrogen, a halogen group, a hydrocarbon group having 1 to 20 carbon atoms, An alkoxy group having 1 to 20 carbon atoms, an alkylamide group having 1 to 20 carbon atoms, a trifluoromethanesulfonic acid group, a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms or a silicon-containing hydrocarbon group having 1 to 20 carbon atoms is shown. .

In general formula (a1), Q ¹¹ is a silylene having 1 to 20 carbon atoms and a hydrocarbon group having 1 to 20 carbon atoms, which bonds two five-membered rings. Group or germylene group. When two hydrocarbon groups are present on the aforementioned silylene group or germylene group, they may be bonded to each other to form a ring structure.
Specific examples of Q ¹¹ include alkylene groups such as methylene, methylmethylene, dimethylmethylene and 1,2-ethylene; arylalkylene groups such as diphenylmethylene; silylene groups; methylsilylene, dimethylsilylene, diethylsilylene, diethylene Alkylsilylene groups such as (n-propyl) silylene, di (i-propyl) silylene, di (cyclohexyl) silylene, (alkyl) (aryl) silylene groups such as methyl (phenyl) silylene; arylsilylene groups such as diphenylsilylene; Alkyl oligosilylene groups such as tetramethyldisilylene; germylene groups; alkylgermylene groups in which the silicon of the above-mentioned divalent hydrocarbon groups having 1 to 20 carbon atoms is replaced with germanium; (alkyl) (aryl) Germylene group; arylgermylene Examples include groups. In these, the silylene group which has a C1-C20 hydrocarbon group, or the germylene group which has a C1-C20 hydrocarbon group is preferable, and an alkylsilylene group and an alkylgermylene group are especially preferable.

Among the compounds represented by the general formula (a1), specific examples of preferable compounds are given below.
Dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-thienyl) -4-phenyl -Indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-diphenylsilylenebis {2 -(5-Methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylgermylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl} ] Hafnium, dichloro [1,1'-dimethylgermylenebis {2- (5-methyl-2-thienyl) -4-phenyl-indenyl}] hafnium, dic B [1,1′-dimethylsilylenebis {2- (5-t-butyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5- Trimethylsilyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-phenyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [ 1,1′-dimethylsilylenebis {2- (4,5-dimethyl-2-furyl) -4-phenyl-indenyl}] hafnium dichloride, dichloro [1,1′-dimethylsilylenebis {2- (2-benzofuryl) ) -4-Phenyl-indenyl}] hafnium, dichloro [1,1′-diphenylsilylenebis {2- (5-methyl-2-furyl) -4- Enyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-methyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2- (5-Methyl-2-furyl) -4-isopropyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-furfuryl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-chlorophenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5 -Methyl-2-furyl) -4- (4-fluorophenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-Methyl-2-furyl) -4- (4-trifluoromethylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4 -(4-t-butylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4- (1-naphthyl) -indenyl}] hafnium, dichloro [1 , 1′-dimethylsilylenebis {2- (2-furyl) -4- (2-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4- (2-phenanthryl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4- (9-phenanthryl) -indenyl}] hafni Dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (1-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2 -(5-Methyl-2-furyl) -4- (2-naphthyl) -indenyl}] hafnium, dichloro [1,1'-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- ( 2-phenanthryl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (9-phenanthryl) -indenyl}] hafnium, dichloro [1, 1′-dimethylsilylenebis {2- (5-t-butyl-2-furyl) -4- (1-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2 -(5-t-butyl-2-furyl) -4- (2-naphthyl) -indenyl}] hafnium, dichloro [1,1'-dimethylsilylenebis {2- (5-t-butyl-2-furyl) -4- (2-phenanthryl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-tert-butyl-2-furyl) -4- (9-phenanthryl) -indenyl}] Hafnium, dichloro [1,1′-dimethylsilylene (2-methyl-4-phenyl-indenyl) {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1 ′ -Dimethylsilylene (2-methyl-4-phenyl-indenyl) {2- (5-methyl-2-thienyl) -4-phenyl-indenyl}] hafnium, and the like. .

  Of these, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethyl gel are more preferable. Mylenebis {2- (5-methyl-2-thienyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- ( 4-chlorophenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-naphthyl-indenyl}] hafnium, dichloro [1,1′-dimethyl Silylenebis {2- (5-methyl-2-furyl) -4- (4-t-butylphenyl) -indenyl}] hafnium.

  Particularly preferred is dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2- (5-Methyl-2-furyl) -4-naphthyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-t -Butylphenyl) -indenyl}] hafnium.

(Ii) Component [A-2]: Compound represented by general formula (a2)

[In General Formula (a2), each of R ²¹ and R ²² is independently a hydrocarbon group having 1 to 6 carbon atoms, and R ²³ and R ²⁴ are each independently halogen, silicon, oxygen, It is a C6-C16 aryl group which may contain sulfur, nitrogen, boron, phosphorus, or a plurality of hetero elements selected from these. X ²¹ and Y ²¹ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon having 1 to 20 carbon atoms. Group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group, or a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, Q ²¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms, carbon number It represents a silylene group or a germylene group which may have 1 to 20 hydrocarbon groups. M ²¹ is zirconium or hafnium. ]

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

R ²³ and R ²⁴ each independently contain a halogen having 6 to 30 carbon atoms, preferably 6 to 24 carbon atoms, halogen, silicon, or a plurality of hetero elements selected from these. It is a good aryl group. 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.

Further, the X ²¹ and Y ²¹ are auxiliary ligands to generate an active metallocene having olefin polymerizability reacts with the cocatalyst component (B). Therefore, as long as this object is achieved, X ²¹ and Y ²¹ are not limited in the type of ligand, and are independently hydrogen, halogen group, hydrocarbon group having 1 to 20 carbon atoms, carbon An alkoxy group having 1 to 20 carbon atoms, an alkylamide group having 1 to 20 carbon atoms, a trifluoromethanesulfonic acid group, a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms, or a silicon-containing hydrocarbon group having 1 to 20 carbon atoms is shown.

Q ²¹ is a bonding group that bridges two conjugated five-membered ring ligands, and a silylene having a C 1-20 divalent hydrocarbon group and a C 1-20 hydrocarbon group. Or a germylene group having a hydrocarbon group having 1 to 20 carbon atoms, preferably a substituted silylene group or a substituted germylene group. The substituent bonded to silicon and germanium is preferably a hydrocarbon group having 1 to 12 carbon atoms, and two substituents may be linked. Specific examples include methylene, dimethylmethylene, ethylene-1,2-diyl, dimethylsilylene, diethylsilylene, diphenylsilylene, methylphenylsilylene, 9-silafluorene-9,9-diyl, dimethylsilylene, diethylsilylene, Examples thereof include diphenylsilylene, methylphenylsilylene, 9-silafluorene-9,9-diyl, dimethylgermylene, diethylgermylene, diphenylgermylene, methylphenylgermylene and the like.

Further, M ²¹ is zirconium or hafnium, preferably hafnium.

Non-limiting examples of the metallocene compound represented by the general formula (a2) include the following.
However, only representative exemplary compounds are described avoiding many complicated examples. Moreover, although the compound whose center metal is hafnium was described, it is obvious that the same zirconium compound can be used, and various ligands, crosslinking groups, or auxiliary ligands can be arbitrarily used.
Dichloro {1,1′-dimethylsilylenebis (2-methyl-4-phenyl-4-hydroazurenyl)} hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4 -Hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-t-butylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2-methyl-4- (4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-chloro-4-t-butylphenyl)- 4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-methyl) -4-t-butylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-chloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium , Dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-methyl-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl -4- (1-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (2-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [1, 1'-dimethylsilylenebis {2-methyl-4- (4-chloro-2-naphthyl) -4-hydroazule Nil}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (2-fluoro-4-biphenylyl) -4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2-methyl-4- (2-chloro-4-biphenylyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (9-phenanthryl) -4-hydroazurenyl} ] Hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (4-chlorophenyl) -4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-n-propyl-] 4- (3-Chloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1 1'-dimethylsilylenebis {2-ethyl-4- (3-chloro-4-t-butylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1'-dimethylsilylenebis {2-ethyl-4- (3-Methyl-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylgermylenebis {2-methyl-4- (2-fluoro-4-biphenylyl) -4-hydroazurenyl} ] Hafnium, dichloro [1,1'-dimethylgermylenebis {2-methyl-4- (4-tert-butylphenyl) -4-hydroazulenyl}] hafnium, dichloro [1,1 '-(9-silafluorene- 9,9-diyl) bis {2-ethyl-4- (4-chlorophenyl) -4-hydroazulenyl}] hafnium, dichloro [1,1 ′ -Dimethylsilylenebis {2-ethyl-4- (4-chloro-2-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [1,1'-dimethylsilylenebis {2-ethyl-4- (2-fluoro- 4-biphenylyl) -4-hydroazurenyl}] hafnium, dichloro [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3,5-dichloro-4-trimethylsilylphenyl) ) -4-hydroazurenyl}] hafnium, and the like.

  Of these, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- Methyl-4- (3-chloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (2-fluoro-4-biphenylyl) -4 -Hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (4-chloro-2-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-Ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4-hydroazurenyl}] ha Dichloro, [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3,5-dichloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, is there.

  Particularly preferably, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl -4- (2-Fluoro-4-biphenylyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4- Hydroazurenyl}] hafnium, dichloro [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3,5-dichloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] Hafnium.

(2) Catalyst component (B)
Next, the catalyst component (B) used in the present invention is an ion-exchange layered silicate.
(I) Types of ion-exchangeable layered silicate In the present invention, the ion-exchangeable layered silicate used as a raw material (hereinafter simply abbreviated as “silicate”) means that the surfaces formed by ionic bonds or the like have a binding force to each other. The silicate compound has a crystal structure stacked in parallel with each other, and the contained ions are exchangeable. Most silicates are naturally produced mainly as a main component of clay minerals, and therefore often contain impurities (quartz, cristobalite, etc.) other than ion-exchangeable layered silicates. But you can. Depending on the type, amount, particle diameter, crystallinity, and dispersion state of these impurities, it may be preferable to pure silicate, and such a complex is also included in component (B).
In addition, the raw material of this invention refers to the silicate of the previous stage which performs the chemical treatment of this invention mentioned later. Further, the silicate used in the present invention is not limited to a natural product, and may be an artificial synthetic product. You may include them.

Specific examples of the silicate include the following layered silicates described in Haruo Shiramizu “Clay Mineralogy” Asakura Shoten (1995).
That is, montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stemite and other smectites, vermiculite and other vermiculites, mica, illite, sericite and sea chlorite and other mica, attapulgite, sepiolite and palygorskite , Bentonite, pyrophyllite, talc, chlorite group, etc.

  The silicate used as a raw material in the present invention is preferably a silicate in which the main component silicate has a 2: 1 type structure, more preferably a smectite group, and particularly preferably montmorillonite. The type of interlayer cation is not particularly limited, but a silicate containing an alkali metal or an alkaline earth metal as a main component of the interlayer cation is preferable from the viewpoint of being relatively easy and inexpensive to obtain as an industrial raw material.

(Ii) Chemical treatment of ion-exchange layered silicate The ion-exchange layered silicate of the catalyst component (B) according to the present invention can be used as it is without any particular treatment, but it is preferable to perform a chemical treatment. . Here, the chemical treatment of the ion-exchanged layered silicate may be any of a surface treatment that removes impurities adhering to the surface and a treatment that affects the structure of the clay. Treatment, alkali treatment, salt treatment, organic matter treatment and the like.

<Acid treatment>:
In addition to removing impurities on the surface, the acid treatment can elute part or all of cations such as Al, Fe, Mg, etc. having a crystal structure.
The acid used in the acid treatment is preferably selected from hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid and oxalic acid.
Two or more salts (described in the next section) and acid may be used in the treatment. The treatment conditions with salts and acids are not particularly limited. Usually, the salt and acid concentrations are 0.1 to 50% by weight, the treatment temperature is room temperature to boiling point, and the treatment time is 5 minutes to 24 hours. It is preferable to carry out the process under the condition of selecting and eluting at least a part of the substance constituting at least one compound selected from the group consisting of ion-exchangeable layered silicates. In addition, salts and acids are generally used in an aqueous solution.
In the present invention, a combination of the following acids and salts may be used as the treatment agent. Moreover, the combination of these acids and salts may be sufficient.

<Salt treatment>:
In the present invention, 40% or more, preferably 60% or more of the exchangeable Group 1 metal cation contained in the ion-exchangeable layered silicate before being treated with salts is dissociated from the salts shown below. It is preferable to ion exchange with cations.
The salt used in the salt treatment for the purpose of ion exchange is a group consisting of a cation containing at least one atom selected from the group consisting of group 1 to 14 atoms, a halogen atom, an inorganic acid, and an organic acid. A compound comprising at least one anion selected from the group consisting of at least one anion selected from the group consisting of 2 to 14 atoms, and Cl, Br, I, F, PO. ₄ , SO ₄ , NO ₃ , CO ₃ , C ₂ O ₄ , ClO ₄ , OOCCH ₃ , CH ₃ COCHCOCH ₃ , OCl ₂ , O (NO ₃ ) ₂ , O (ClO ₄ ) ₂ , O (SO ₄ ), At least one anion selected from the group consisting of OH, O ₂ Cl ₂ , OCl ₃ , OOCH, OOCCH ₂ CH ₃ , C ₂ H ₄ O ₄ and C ₅ H ₅ O ₇ Is a compound consisting of

Specific examples of such _{salts, LiF, LiCl, LiBr, LiI} , Li 2 SO 4, Li (CH 3 COO), LiCO 3, Li (C 6 H 5 O 7), LiCHO 2, LiC 2 O 4 , LiClO ₄ , Li ₃ PO ₄ , CaCl ₂ , CaSO ₄ , CaC ₂ O ₄ , Ca (NO ₃ ) ₂ , Ca ₃ (C ₆ H ₅ O ₇ ) ₂ , MgCl ₂ , MgBr ₂ , MgSO ₄ , Mg ( PO ₄ ) ₂ , Mg (ClO ₄ ) ₂ , MgC ₂ O ₄ , Mg (NO ₃ ) ₂ , Mg (OOCCH ₃ ) ₂ , MgC ₄ H ₄ O _{4 and the} like.
Further, Ti (OOCCH ₃ ) ₄ , Ti (CO ₃ ) ₂ , Ti (NO ₃ ) ₄ , Ti (SO ₄ ) ₂ , TiF ₄ , TiCl ₄ , Zr (OOCCH ₃ ) ₄ , Zr (CO ₃ ) ₂ , Zr (NO ₃ ) ₄ , Zr (SO ₄ ) ₂ , ZrF ₄ , ZrCl ₄ , ZrOCl ₂ , ZrO (NO ₃ ) ₂ , ZrO (ClO ₄ ) ₂ , ZrO (SO ₄ ), HF (OOCCH ₃ ) ₄ , HF (CO ₃ ) ₂ , HF (NO ₃ ) ₄ , HF (SO ₄ ) ₂ , HFOCl ₂ , HFF ₄ , HFCl ₄ , V (CH ₃ COCHCOCH ₃ ) ₃ , VOSO ₄ , VOCl ₃ , VCl ₃ , VCl ₄ , VBr _{3 and the} like.

Also, Cr (CH ₃ COCHCOCH ₃ ) ₃ , Cr (OOCCH ₃ ) ₂ OH, Cr (NO ₃ ) ₃ , Cr (ClO ₄ ) ₃ , CrPO ₄ , Cr ₂ (SO ₄ ) ₃ , CrO ₂ Cl ₂ , CrF ₃ , CrCl ₃ , CrBr ₃ , CrI ₃ , Mn (OOCCH ₃ ) ₂ , Mn (CH ₃ COCHCOCH ₃ ) ₂ , MnCO ₃ , Mn (NO ₃ ) ₂ , MnO, Mn (ClO ₄ ) ₂ , MnF ₂ , MnCl ₂ , Fe (OOCCH ₃ ) ₂ , Fe (CH ₃ COCHCOCH ₃ ) ₃ , FeCO ₃ , Fe (NO ₃ ) ₃ , Fe (ClO ₄ ) ₃ , FePO ₄ , FeSO ₄ , Fe ₂ (SO ₄ ) ₃ , FeF ₃ , FeCl ₃ , FeC ₆ H ₅ O _{7 and the} like.

Further, Co (OOCCH ₃ ) ₂ , Co (CH ₃ COCHCOCH ₃ ) ₃ , CoCO ₃ , Co (NO ₃ ) ₂ , CoC ₂ O ₄ , Co (ClO ₄ ) ₂ , Co ₃ (PO ₄ ) ₂ , CoSO ₄ , CoF ₂ , CoCl ₂ , NiCO ₃ , Ni (NO ₃ ) ₂ , NiC ₂ O ₄ , Ni (ClO ₄ ) ₂ , NiSO ₄ , NiCl ₂ , NiBr _{2 and the} like.

Furthermore, Zn (OOCCH ₃ ) ₂ , Zn (CH ₃ COCHCOCH ₃ ) ₂ , ZnCO ₃ , Zn (NO ₃ ) ₂ , Zn (ClO ₄ ) ₂ , Zn ₃ (PO ₄ ) ₂ , ZnSO ₄ , ZnF ₂ , ZnCl ₂ , AlF ₃ , AlCl ₃ , AlBr ₃ , AlI ₃ , Al ₂ (SO ₄ ) ₃ , Al ₂ (C ₂ O ₄ ) ₃ , Al (CH ₃ COCHCOCH ₃ ) ₃ , Al (NO ₃ ) ₃ , AlPO ₄ , GeCl ₄ , GeBr ₄ , GeI _{4 and the} like.

<Alkali treatment>:
In addition to acid and salt treatment, the following alkali treatment or organic matter treatment may be performed as necessary. Examples of the treating agent used in the alkali treatment include LiOH, NaOH, KOH, Mg (OH) ₂ , Ca (OH) ₂ , Sr (OH) ₂ , Ba (OH) _{2 and the} like.

<Organic treatment>:
Examples of the organic treatment agent used for organic treatment include trimethylammonium, triethylammonium, N, N-dimethylanilinium, triphenylphosphonium, and the like.
Examples of the anion constituting the organic treatment agent include hexafluorophosphate, tetrafluoroborate, tetraphenylborate and the like other than the anions exemplified as the anion constituting the salt treatment agent. It is not limited to these.

  Moreover, these processing agents may be used independently and may be used in combination of 2 or more types. These combinations may be used in combination for the treatment agent added at the start of the treatment, or may be used in combination for the treatment agent added during the treatment. The chemical treatment can be performed a plurality of times using the same or different treatment agents.

These ion-exchange layered silicates usually contain adsorbed water and interlayer water. In the present invention, it is preferable to remove these adsorbed water and interlayer water and use them as the catalyst component (B).
The heat treatment method of the ion-exchange layered silicate adsorbed water and interlayer water is not particularly limited, but it is necessary to select conditions so that interlayer water does not remain and structural destruction does not occur. The heating time is 0.5 hour or longer, preferably 1 hour or longer. At that time, the water content of the catalyst component (B) after removal is 3% by weight or less when the water content is 0% by weight when dehydrated for 2 hours under the conditions of a temperature of 200 ° C. and a pressure of 1 mmHg. It is preferably 1% by weight or less.

  As described above, in the present invention, the catalyst component (B) is particularly preferably an ion-exchange layered silicic acid having a water content of 3% by weight or less obtained by performing a salt treatment and / or an acid treatment. Salt.

  The ion-exchange layered silicate is preferable because it can be treated with a catalyst component (C) described later before use as a catalyst or as a catalyst. Although there is no restriction | limiting in the usage-amount of the catalyst component (C) with respect to 1g of ion-exchange layered silicate, Usually, 20 mmol or less, Preferably it is 0.5 mmol or more and 10 mmol or less. There is no limitation on the treatment temperature and time, the treatment temperature is usually 0 ° C. or more and 70 ° C. or less, and the treatment time is 10 minutes or more and 3 hours or less. It is also possible and preferable to wash after the treatment. As the solvent, the same hydrocarbon solvent as that used in the preliminary polymerization and slurry polymerization described later is used.

  The catalyst component (B) is preferably spherical particles having an average particle size of 5 μm or more. If the particle shape is spherical, a natural product or a commercially available product may be used as it is, or a particle whose particle shape and particle size are controlled by granulation, sizing, fractionation, or the like may be used.

Examples of the granulation method used here include agitation granulation method and spray granulation method, but commercially available products can also be used.
Moreover, you may use organic substance, an inorganic solvent, inorganic salt, and various binders in the case of granulation.
The spherical particles obtained as described above desirably have a compressive fracture strength of 0.2 MPa or more, particularly preferably 0.5 MPa or more, in order to suppress crushing and generation of fine powder in the polymerization process. In the case of such particle strength, the effect of improving the particle properties is effectively exhibited especially when prepolymerization is performed.

(3) Catalyst component (C)
The catalyst component (C) used in the present invention is an organoaluminum compound. Organic aluminum compounds used as the catalyst component (C) has the general ^{_{formula: (AlR 11 q Z 3-}} q) a compound represented by _p is suitable.
In the present invention, it goes without saying that the compounds represented by this formula can be used singly, mixed in plural or in combination. In this formula, R ¹¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and Z represents a halogen, hydrogen, an alkoxy group, or an amino group. q represents an integer of 1 to 3, and p represents an integer of 1 to 2, respectively. R ¹¹ is preferably an alkyl group, and Z is a chlorine atom when it is a halogen atom, a C 1-8 alkoxy group when it is an alkoxy group, and a C 1 atom when it is an amino group. Eight amino groups are preferred.

  Specific examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, trinormaloctylaluminum, trinormaldecylaluminum, diethylaluminum chloride, diethylaluminum. Examples thereof include sesquichloride, diethylaluminum hydride, diethylaluminum ethoxide, diethylaluminum dimethylamide, diisobutylaluminum hydride, and diisobutylaluminum chloride. Of these, trialkylaluminum and alkylaluminum hydride having p = 1 and q = 3 are preferable. More preferably, R11 is a trialkylaluminum having 1 to 8 carbon atoms.

(4) Catalyst Formation / Preliminary Polymerization The catalyst according to the present invention is formed by bringing the above-mentioned components into contact with each other in a (preliminary) polymerization tank simultaneously or continuously, or once or multiple times. Can do.
The contact of each component is usually carried out in an aliphatic hydrocarbon or aromatic hydrocarbon solvent. Although a contact temperature is not specifically limited, It is preferable to carry out between -20 degreeC and 150 degreeC. As the contact order, any desired combination can be used, but particularly preferable ones for each component are as follows.
When the catalyst component (C) is used, before the catalyst component (A) and the catalyst component (B) are contacted, the catalyst component (A), or the catalyst component (B), or the catalyst component (A) and the catalyst Contacting catalyst component (C) with both components (B), or contacting catalyst component (C) with catalyst component (A) and catalyst component (B), or catalyst component Although it is possible to contact the catalyst component (C) after bringing the catalyst component (B) into contact with (A), it is preferable that the catalyst component be brought into contact with the catalyst component (A) before contacting the catalyst component (B). It is a method of contacting any of the component (C).
Moreover, after contacting each component, it is possible to wash with an aliphatic hydrocarbon or an aromatic hydrocarbon solvent.

  The amount of the catalyst components (A), (B) and (C) used in the present invention is arbitrary. For example, the amount of the catalyst component (A) used relative to the catalyst component (B) is preferably in the range of 0.1 μmol to 1000 μmol, particularly preferably 0.5 μmol to 500 μmol, relative to 1 g of the catalyst component (B). The amount of the catalyst component (C) used relative to the catalyst component (B) is preferably in the range of 0.01 to 1000 mmol, particularly preferably 0.05 to 500 mmol, with respect to 1 g of the catalyst component (B). Therefore, the amount of the catalyst component (C) relative to the catalyst component (A) is preferably in the range of 0.01 to 5 × 10 6, particularly preferably 0.1 to 100 in terms of the molar ratio of the transition metal.

Although the ratio of component [A-1] and component [A-2] used by this invention is arbitrary in the range with which the characteristic of a propylene polymer is satisfy | filled, each component [A-1] and [A-2] The molar ratio of the transition metal of [A-1] to the total amount of is preferably 0.30 or more and 0.99 or less.
From component [A-1], a low molecular weight terminal vinyl macromer is produced, and from component [A-2], a high molecular weight product obtained by copolymerizing a part of the macromer is produced. Therefore, by changing the ratio of the component [A-1], the average molecular weight, molecular weight distribution, bias of the molecular weight distribution toward the high molecular weight side, very high molecular weight component, branch (amount, length, Distribution) can be controlled, whereby the melt properties such as strain hardening degree, melt tension, and melt spreadability can be controlled. In order to produce a propylene-based polymer for applications requiring higher melt properties and high catalytic activity, it is particularly preferably 0.40 or more, and further preferably 0.5 or more. The upper limit is particularly preferably 0.90 or less, and more preferably 0.8 or less.
Further, it is possible to adjust the balance between the average molecular weight and the catalyst activity with respect to the amount of hydrogen used.

  The catalyst according to the present invention is subjected to a prepolymerization treatment consisting of a small amount of polymerization by bringing an olefin into contact therewith. By performing the prepolymerization treatment, gel formation can be prevented when the main polymerization is performed. The reason is considered to be that long-chain branches can be uniformly distributed among the polymer particles when the main polymerization is performed, and the melt properties can be improved thereby.

  The olefin used in the prepolymerization is not particularly limited, but propylene, ethylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, Styrene and the like can be exemplified. The olefin feed method may be any method such as a feed method for maintaining the olefin at a constant rate or a constant pressure in the reaction tank, a combination thereof, or a stepwise change. The prepolymerization temperature and time are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The amount of prepolymerization is preferably 0.01 to 100, more preferably 0.1 to 50 with respect to the component (B). Moreover, a component (C) can also be added or added at the time of prepolymerization. It is also possible to wash after the prepolymerization.

  In addition, a method of coexisting a polymer such as polyethylene or polypropylene, or a solid of an inorganic oxide such as silica or titania, at the time of contacting or after contacting each of the above components is also possible.

(5) Use of Catalyst / Propylene Polymerization As the polymerization mode, any mode can be adopted as long as the olefin polymerization catalyst including the catalyst components (A), (B) and (C) and the monomer are in efficient contact with each other. .
Specifically, a slurry method using an inert solvent, a so-called bulk method, a solution polymerization method, or a substantially liquid solvent without using an inert solvent as a solvent. A gas phase method can be used. Further, a method of performing continuous polymerization or batch polymerization is also applied. In addition to single-stage polymerization, it is possible to carry out multistage polymerization of two or more stages.

In the case of slurry polymerization, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene, toluene or the like is used alone or as a mixture as a polymerization solvent.
The polymerization temperature is 0 ° C. or higher and 150 ° C. or lower. In particular, when bulk polymerization is used, 40 ° C. or higher is preferable, and 50 ° C. or higher is more preferable. The upper limit is preferably 80 ° C. or lower, and more preferably 75 ° C. or lower.
Furthermore, when using vapor phase polymerization, 40 degreeC or more is preferable, More preferably, it is 50 degreeC or more. The upper limit is preferably 100 ° C. or lower, more preferably 90 ° C. or lower.

The polymerization pressure is 1.0 MPa or more and 5.0 MPa or less. In particular, when bulk polymerization is used, the pressure is preferably 1.5 MPa or more, more preferably 2.0 MPa or more. The upper limit is preferably 4.0 MPa or less, more preferably 3.5 MPa or less.
Furthermore, when using vapor phase polymerization, 1.2 MPa or more is preferable, and 1.5 MPa or more is more preferable. The upper limit is preferably 3.0 MPa or less, more preferably 2.5 MPa or less.

Further, hydrogen can be used as a molecular weight regulator and for the purpose of improving the activity.
Hydrogen is used in a feed ratio of 0 to 1 mol% with respect to propylene, preferably 0.0001 mol% or more, and more preferably 0.001 mol% or more.
By changing the amount of hydrogen used, in addition to the average molecular weight of the polymer produced, the molecular weight distribution, the bias of the molecular weight distribution toward the high molecular weight side, very high molecular weight components, branching (amount, length, distribution) The melt physical properties such as strain hardening degree, melt tension, and melt spreadability can be controlled.

The propylene polymer used in the present invention may be a propylene homopolymer, or an α-olefin having about 2 to 20 carbon atoms (excluding those used as a monomer) as a comonomer in addition to the propylene monomer. It may be a propylene α-olefin copolymer obtained by copolymerization. The (total) comonomer content in the propylene-based polymer is in the range of 0 mol% or more and 20 mol% or less, and a plurality of the above-mentioned comonomers can be used. Specifically, ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene.
Among these, in order to obtain the propylene-based polymer of the present invention in a good balance between melt properties and catalytic activity, it is preferable that the comonomer such as ethylene be 5 mol% or less. In order to obtain a polymer having particularly high rigidity, the comonomer contained in the polymer should be 1 mol% or less, and propylene homopolymerization is more preferable.

(6) Consideration of polymerization mechanism It is considered that the formation of a macromer is generated by a special chain transfer reaction generally called β-methyl elimination. In the present invention, the component [A-1] having a specific structure is In the relatively low temperature range (40 ° C. to 80 ° C.), the selectivity of the β-methyl elimination reaction during the growth termination reaction is high, and the ratio of the β-methyl elimination reaction to the polymer growth reaction is that of the conventional structure. The inventors have found that it is larger than the complex.
In the past, in order to preferentially cause the β-methyl elimination reaction, it could only be produced under special conditions (low pressure, high temperature polymerization, no hydrogen addition) in slurry polymerization with a low propylene concentration, By using the component [A-1] having a specific structure of the present invention, industrially effective bulk polymerization or gas phase polymerization, and practical pressure conditions (1.0 to 3.0 MPa) and temperature conditions It was found that the production was possible under (40 ° C. to 80 ° C.).

Furthermore, surprisingly, by adding hydrogen, in the conventional method, the chain transfer reaction by hydrogen is superior to the β-methyl elimination reaction, whereas the cause is unknown, but The propylene-based polymer production method is characterized by a small change in the balance between macromer formation and growth reaction even when hydrogen is added, and it has been found that the selectivity of the macromer remains almost unchanged even in the presence of hydrogen. Moreover, hydrogen has an activity improving effect.
This is because, in the past, it has been necessary to perform a multi-stage polymerization in which a macromer copolymerization is performed after a macromer generation step which is a special condition (low pressure, high temperature, no hydrogen addition), whereas the component [A-2 ], It was found that the macromer production step and the macromer copolymerization step can be performed under the same conditions, that is, simultaneous polymerization and single-stage polymerization can be performed.

On the other hand, since the component [A-2] has a specific structure, it has a high ability to copolymerize a macromer even though it does not have the ability to form a terminal vinyl structure, and further, compared with the component [A-1]. And has the ability to produce higher molecular weight polymers. Further, when hydrogen is added, the activity is improved, and the molecular weight is lowered due to chain transfer by hydrogen.
Conventionally, since macromer production and macromer copolymerization are produced with a single complex, that is, since a polymer is produced with the same complex of component [A-1] and component [A-2], macromer production is performed. If either the capacity or the macromer copolymerization capacity is insufficient, the amount of branching component introduced is insufficient on the high molecular weight side, or if hydrogen is used to adjust the molecular weight, the production amount of the macromer itself decreases. There was a problem of doing.

However, in the present invention, the component [A-1] having a specific structure having macromer generation ability and the component [A-2] having a specific structure having high molecular weight and macromer copolymerization ability are combined in a specific method. By using it as a catalyst, it is an industrially effective method such as bulk polymerization or gas phase polymerization, especially in single-stage polymerization under practical pressure-temperature conditions, and using hydrogen as a molecular weight regulator. It has been found that it is possible to produce a long-chain branched propylene-based polymer having the following physical properties:
Further, conventionally, it has been necessary to increase the branch generation efficiency by reducing the crystallinity by using a component having low stereoregularity, but in the method of the present invention, a component having sufficiently high stereoregularity, It can be introduced into the side chain by a simple method.

1-2. Propylene polymer (Y)
About the propylene-type resin component which comprises the propylene-type resin composition used for the polypropylene-type injection foaming molding of this invention, a propylene-type polymer (Y) can be used together with the said propylene-type polymer (X). The propylene polymer (Y) is different from the propylene polymer (X). Specifically, the propylene homopolymer, the propylene / ethylene random copolymer, the propylene / ethylene block copolymer, etc. A copolymer of propylene and an α-olefin excluding propylene, a copolymer of propylene and a vinyl compound, a copolymer of propylene and a vinyl ester, a copolymer of propylene and an unsaturated organic acid or a derivative thereof, Examples thereof include copolymers of propylene and conjugated dienes, copolymers of propylene and nonconjugated polyenes, and mixtures thereof. Among them, propylene homopolymers, propylene / ethylene random copolymers, propylene / ethylene block copolymers, and the like. Polymers and mixtures thereof are preferred.

  The propylene polymer (Y) has a weight average molecular weight in the range of 50,000 to 800,000. The measurement of a weight average molecular weight is the same as the measuring method in propylene polymer (X). When the weight average molecular weight of the propylene-based polymer (Y) is smaller than 50,000, the foaming cell is broken and the foaming ratio is lowered. When the weight average molecular weight exceeds 800,000, the appearance of the foamed molded product becomes inferior, for example, a flow mark is generated. From the balance of expansion ratio and appearance, the weight average molecular weight is preferably 80,000 to 650,000, more preferably 100,000 to 500,000, and still more preferably 120,000 to 260,000.

  Furthermore, the propylene-based polymer (Y) preferably has a strain hardening degree (λmax) in the measurement of elongational viscosity of less than 1.5, more preferably less than 1.1, and even more preferably 0.9 or more. It is less than 1.05. By carrying out like this, the external appearance of a foaming molding is improved more.

The method for producing the propylene-based polymer (Y) is not particularly limited, and can be appropriately selected from known methods and conditions, but a propylene-based resin having no branched structure can be obtained. The method and conditions are preferable.
As the polymerization catalyst, a highly stereoregular catalyst is usually used, and examples thereof include a Ziegler catalyst and a metallocene catalyst.
As such a production method, a production process such as a gas phase polymerization method, a liquid phase bulk polymerization method, or a slurry polymerization method in the presence of the catalyst is generally used.

The propylene resin component is composed of 6 to 100% by weight of the propylene polymer (X) and 0 to 94% by weight of the propylene polymer (Y).
If the propylene polymer (X) is 100% by weight in the propylene resin component, the moldability is good due to its characteristic properties, and the foam molded product has a high expansion ratio, uniform foaming, surface Excellent appearance.
On the other hand, when the propylene polymer (X) and the propylene polymer (Y) are used in combination in the propylene resin component, good moldability is obtained by the propylene polymer (X), and foam molding is performed. The propylene polymer (X) is a total amount of the propylene polymer (X) and the propylene polymer (Y) so that a high foaming ratio and good foaming uniformity can be provided. At least 6% by weight, preferably at least 7% by weight, more preferably at least 8% by weight, even more preferably at least 10% by weight (6% by weight or more, preferably 7% by weight or more, more preferably 8% by weight or more, (More preferably 10% by weight or more) is used, and in order to further add the properties of the propylene polymer (Y), the propylene polymer (Y) is propylene. At least 10 wt%, preferably at least 20 wt%, more preferably at least 30 wt% (10 wt% or more, preferably 20 wt% or more) based on the total amount of the polymer (X) and the propylene-based polymer (Y). , More preferably 30% by weight or more).

2. Foaming agent The foaming agent that can be used in the present invention is not particularly limited as long as it can be usually used for injection foam molding, such as a chemical foaming agent and a physical foaming agent. The chemical foaming agent is mixed with the resin in advance and then supplied to the injection molding machine, and decomposes in the cylinder to generate a gas such as carbon dioxide. Examples of the foaming agent include inorganic compounds such as ammonium carbonate and sodium bicarbonate, and organic compounds such as azo compounds, sulfohydrazide compounds, nitroso compounds, and azide compounds. Examples of the azo compound include azodicarbonamide (ADCA), 2,2-azoisobutyronitrile, azohexahydrobenzonitrile, diazoaminobenzene, and the like. Examples of the sulfohydrazide compound include benzenesulfohydrazide, benzene-1,3-disulfohydrazide, diphenylsulfone-3,3-disulfohydrazide, diphenyloxide-4,4-disulfohydrazide and the like. Examples of the nitroso compound include N, N-dinitrosopentamethylenetetramine (DNPT), N, N-dimethyl terephthalate and the like. Examples of the azide compound include terephthalazide and p-tert-butylbenzazide.

  A physical foaming agent is injected into a molten resin in a cylinder of a molding machine as a gaseous or supercritical fluid, dispersed or dissolved, and functions as a foaming agent by being released from pressure after being injected into a mold. Is. Physical foaming agents include aliphatic hydrocarbons such as propane and butane, alicyclic hydrocarbons such as cyclobutane and cyclopentane, halogenated hydrocarbons such as chlorodifluoromethane and dichloromethane, nitrogen, carbon dioxide, air, etc. Inorganic gas. You may use these individually or in mixture of 2 or more types.

  Among these foaming agents, normal injection molding machines can be used safely, and uniform fine bubbles are easily obtained. Chemical foaming agents are inorganic chemical foaming agents, physical foaming agents are nitrogen and carbon dioxide. Inorganic gas such as air is preferable. These foaming agents include, for example, foaming aids such as organic acids such as citric acid and inorganic fine particles such as talc and lithium carbonate, in order to stably and uniformly make the foamed foam air bubbles. A nucleating agent such as may be added. In general, the inorganic chemical foaming agent is preferably used as a masterbatch of a polyolefin resin having a concentration of 10 to 50% by weight from the viewpoints of handleability, storage stability, and dispersibility in a propylene polymer.

  The amount of the foaming agent used may be appropriately set depending on the foaming ratio of the final product, the type of foaming agent, and the resin temperature at the time of molding. Usually, the propylene-based polymer (X) and the propylene-based polymer (Y) In the case of an inorganic chemical foaming agent, for example, in the case of an inorganic chemical foaming agent, preferably 100 parts by weight of propylene polymer (X) It is selected in the range of 0.5 to 5 parts by weight. In this way, it is easy to obtain a foamed molded article having a foaming ratio of 2 times or more and uniform fine cells.

3. Other compounding agents The propylene-based resin composition used in the polypropylene-based injection-foamed molded article of the present invention has various additives usually used for polyolefins, such as nucleation, as necessary, as long as the object of the present invention is not impaired. An agent, an antioxidant, a neutralizer, a light stabilizer, an ultraviolet absorber, an inorganic filler, an antiblocking agent, a lubricant, an antistatic agent, a metal deactivator, and the like can be appropriately blended.

  Examples of antioxidants include phenolic antioxidants, phosphite antioxidants, and thio antioxidants, and examples of neutralizing agents include higher fatty acid salts such as calcium stearate and zinc stearate. Examples of the light stabilizer and the ultraviolet absorber include hindered amines, nickel complex compounds, benzotriazoles, and benzophenones.

As nucleating agents, sorbitols such as sodium 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphate, talc, 1,3,2,4-di (p-methylbenzylidene) sorbitol Compound, hydroxy-di (aluminum t-butylbenzoate, 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphoric acid and aliphatic monocarboxylic acid lithium salt having 8 to 20 carbon atoms (Asahi Examples include Denka Co., Ltd. product name NA21).
Examples of inorganic fillers and anti-blocking agents include calcium carbonate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate, and examples of lubricants include higher fatty acid amides such as stearic acid amide. it can.
Furthermore, examples of the antistatic agent include fatty acid partial esters such as glycerin fatty acid monoester, and examples of the metal deactivator include triazines, phosphones, epoxies, triazoles, hydrazides, and oxamides. it can.

II. Preparation Method of Propylene Resin Composition As a preparation method of the propylene resin composition used in the present invention, the propylene polymer (X) in powder form or pellet form, the propylene polymer (Y), and A method of mixing other compounding agents appropriately blended by dry blend, Henschel mixer or the like can be mentioned.

III. Polypropylene Injection Foam Molded Article The polypropylene injection foam molded article of the present invention is formed by injection foam molding of the propylene resin composition, and its production method is based on an injection foam molding method. The injection foam molding method includes an injection process in which the propylene resin composition is injected and filled into a mold cavity in a molten state or a semi-molten state, and a foaming process in which the propylene resin composition is foamed in the mold cavity. Preferably, a molten or semi-molten propylene resin composition in an amount less than the volume of the mold cavity is injected and filled into the mold cavity, and the cavity of the mold cavity is filled with the expansion pressure of the foaming agent. A mold cavity clearance (t0) smaller than a mold cavity clearance (t1) corresponding to the shape position of the final product, which is composed of a short shot method or a mold whose mold is a fixed mold and a movable mold capable of moving forward and backward. ) Is injected and filled with the propylene resin composition in a molten or semi-molten state. Retracting the movable mold up Sensitivity clearance (t1), include mold opening injection molding process allowed to fill the void of the mold cavity by expansion pressure generated by the blowing agent.

IV. Use of polypropylene-based injection-foamed molded article The polypropylene-based injection-foamed molded article of the present invention can provide a foam-molded article having high rigidity, beautiful and excellent surface appearance. Applications of such molded products include: automotive interior parts such as instrument panels and door trims, air-conditioning cases, air cleaner cases, automotive heat-resistant parts such as lamps, automotive exterior parts such as bumpers and back doors, vanity tables, washstands, It can be suitably used for industrial parts such as toiletries such as toiletries.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, the physical properties of polypropylene-based injection-foamed molded articles or their constituent components were measured and evaluated according to the following evaluation methods, and the following resins were used.

1. Evaluation method (1) Melt flow rate (MFR):
In accordance with JIS K6921-2 “Plastics—Polypropylene (PP) molding and extrusion materials—Part 2: How to make test pieces and properties” Test flow: 230 ° C., load 2 .16 kgf) was measured. The unit is g / 10 minutes.
(2) Molecular weight and molecular weight distribution (Mw, Mn, Q value):
It was measured by the method described in the present specification by gel permeation chromatography (GPC).
(3) ME (memory effect):
Polymer that was extruded through an orifice at a temperature of 190 ° C. using a melt indexer manufactured by Takara at 190 ° C. with a load and an extrusion speed of 0.1 g / min. Was quenched in ethanol and calculated as a value obtained by dividing the value of the strand diameter at that time by the orifice diameter. This value correlates with Log (MFR), and a large value indicates that the product appearance is improved when the swell is large and injection molded.
(4) mm fraction:
The measurement was carried out by the method described in the present specification using GSX-400 and FT-NMR manufactured by JEOL. The unit is%.
(5) Measurement of ethylene content:
A calibration curve was prepared using 13C-NMR and measured using IR.

(6) Elongation viscosity:
It was measured by the method described in the present specification.
(7) Composition analysis:
A calibration curve was prepared by chemical analysis by the JIS method and measured by fluorescent X-ray.
(8) Melting point (Tm) and crystallization temperature (Tc)
Using a DSC6200 manufactured by Seiko Instruments Inc., a sample piece made into a sheet is packed in a 5 mg aluminum pan, heated from room temperature to 200 ° C. at a heating rate of 100 ° C./minute, held for 5 minutes, and then 10 ° C./minute. The crystallization temperature (Tc) is obtained as the maximum crystal peak temperature (° C.) when the temperature is lowered to 20 ° C. and crystallized, and then the maximum melting peak when the temperature is increased to 200 ° C. at 10 ° C./min. The melting point (Tm) was determined as the temperature (° C.).
(1) Melt flow rate (MFR) [unit: g / 10 min]:
The propylene-based polymer is JIS K7210: 1999, “Method A of plastic-thermoplastic plastic melt mass flow rate (MFR) and melt volume flow rate (MVR)”, condition M (230 ° C., 2.16 kg load). Measured according to

(2) Weight average molecular weight (Mw)
It was measured by the method described in the present specification by gel permeation chromatography (GPC).

(3) mm fraction It measured by the method as described in the said specification using JEOL Co., Ltd. make, GSX-400, and FT-NMR. The unit is%.

(4) Elongation viscosity It measured by the method as described in this specification using the rheometer.

(5) Melting temperature (Tm)
Measurements were made using a Seiko DSC.
After taking 5.0 mg of sample and holding it at 200 ° C. for 5 minutes, it is crystallized at a rate of temperature decrease of 10 ° C./min to 40 ° C. to erase its thermal history, and further melted at a rate of temperature increase of 10 ° C./min. The peak temperature of the melting curve is taken as the melting point. When a plurality of melting points are observed in the resin, the one observed at the highest temperature is defined as the melting point of the resin.

(6) Quantification of ethylene content Measured by ¹³ C-NMR under the same conditions as in the measurement of the mm fraction described above. The ethylene content is calculated according to the analysis method described in Macromolecules 1982 1150.

(7) Molecular weight distribution:
Measurement was performed by the method described above.

(8) Temperature rise elution fractionation (TREF):
The TREF measurement method is as described above using the following apparatus.
(I) TREF part TREF column: 4.3 mmφ × 150 mm stainless steel column Column packing material: 100 μm surface inactive glass beads Heating method: Aluminum heat block Cooling method: Peltier element (Peltier element is cooled by water)
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation Digital Program Controller KP1000 (Valve Oven)
Heating method: Air bath oven Measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve 4-way valve (ii) Sample injection part Injection method: Loop injection method Injection amount: Loop size 0.1ml
Inlet heating method: Aluminum heat block Measurement temperature: 140 ° C
(Iii) Detection unit Detector: Fixed wavelength infrared detector MIRAN 1A manufactured by FOXBORO
Detection wavelength: 3.42 μm
High-temperature flow cell: Micro flow cell for LC-IR Optical path length 1.5mm Window shape 2φ x 4mm oval Synthetic sapphire window Measurement temperature: 140 ° C
(Iv) Pump unit Liquid feed pump: SSC-3461 pump manufactured by Senshu Kagaku Co. (v) Measurement conditions Solvent: o-dichlorobenzene (including 0.5 mg / ml BHT)
Sample concentration: 5 mg / ml
Sample injection volume: 0.1 ml
Solvent flow rate: 1 ml / min

(9) Foaming ratio: The maximum foaming ratio that can reproduce the shape of the cavity in a predetermined molding method was determined.
In the short shot method, the filling rate was changed, and the foaming ratio of the molded product obtained at the minimum filling rate at which the shape of the molded product could reproduce the cavity shape was used.
In the mold opening method, the mold opening amount was changed, and the foaming ratio of the molded product obtained when the mold was opened at the maximum mold opening amount that could reproduce the cavity shape was used.
The specific gravity (dG, dM) of each test piece obtained by cutting from the gate portion and the filling end portion of the foam molded product was measured, and the average value (dG-M) and the specific gravity (d1) of the foam molded product material The ratio was obtained and (d1 / dG-M) = foaming ratio.

(10) Appearance of molded product: The molded product having the maximum expansion ratio was visually judged according to the following evaluation criteria.
○: Specular gloss, minimal swirl mark △; surface fogging, small swirl mark ×: no gloss, swirl mark many (11) Foamed bubble observation: A foam molded product with the maximum expansion ratio was cut out with a sharp blade and the cross section was 20 times The image was enlarged with a magnifying glass and visually judged according to the following evaluation criteria.
○: Bubbles are not broken and the diameter is uniform ×: Bubbles are broken and the diameter is non-uniform

2. Materials used (1) Propylene polymer (X)
The propylene polymers (PP-1) to (PP-5) produced in the following Production Examples 1 to 5 and a commercially available polypropylene resin (PF814) were used. Table 1 shows the properties of the propylene polymers (PP-1) to (PP-5) and the commercially available polypropylene resin (PF814).

[Production Example 1 (PP-1)]
[Synthesis example 1 of catalyst component (A)]:
(1) Synthesis of dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-t-butylphenyl) indenyl}] hafnium: (component [A-1] (Synthesis of Complex 1):
(1-a) Synthesis of 4- (4-t-butylphenyl) -indene:
To a 1000 ml glass reaction vessel, 1-bromo-4-t-butyl-benzene (40 g, 0.19 mol) and dimethoxyethane (400 ml) were added and cooled to -70 ° C. A t-butyllithium-pentane solution (260 ml, 0.38 mol, 1.46 mol / L) was added dropwise thereto. After dropping, the mixture was stirred for 5 hours while gradually returning to room temperature. The mixture was cooled again to −70 ° C., and a dimethoxyethane solution (100 ml) of triisopropyl borate (46 ml, 0.20 mol) was added dropwise thereto. After dropping, the mixture was stirred overnight while gradually returning to room temperature.

Distilled water (100 ml) was added to the reaction solution, and the mixture was stirred for 30 minutes, and then sodium carbonate 50 g in water (150 ml), 4-bromoindene (30 g, 0.15 mol), tetrakis (triphenylphosphino) palladium (5 g, 4 g .3 mmol) was added in order, then the low boiling component was removed and heated at 80 ° C. for 5 hours.
The reaction solution was poured into ice water (1 L), from which ether was extracted three times, and the ether layer was washed with saturated brine until neutral. Sodium sulfate was added thereto and left overnight to dry the reaction solution. Anhydrous sodium sulfate was filtered, the solvent was distilled off under reduced pressure, and the residue was purified by a silica gel column to obtain 4- (4-tert-butylphenyl) -indene (37 g, yield 98%) as a pale yellow liquid.

(1-b) Synthesis of 2-bromo-4- (4-t-butylphenyl) -indene:
To a 1000 ml glass reaction vessel, 4- (4-t-butylphenyl) -indene (37 g, 0.15 mol), dimethyl sulfoxide (400 ml) and distilled water (11 ml) were added, and N-bromosuccinimide (35 g) was added thereto. , 0.20 mol) was gradually added, and the mixture was stirred at room temperature for 1 hour.
The reaction solution was poured into ice water (1 L), and extracted from it three times with toluene. The toluene layer was washed with saturated brine, p-toluenesulfonic acid (4.3 g, 22 mmol) was added, and the mixture was heated to reflux for 2 hours while removing moisture.
The reaction solution was transferred to a separatory funnel and washed with brine until neutral. Sodium sulfate was added thereto and left overnight to dry the reaction solution. Anhydrous sodium sulfate was filtered off, the solvent was distilled off under reduced pressure, and the residue was purified by a silica gel column to give 2-bromo-4- (4-t-butylphenyl) -indene (46 g, yield 95%) as a pale yellow solid. Obtained.

Synthesis of (1-c) 4- (4-t-butylphenyl) -2- (5-methyl-2-furyl) -indene:
Methyl furan (13.8 g, 0.17 mol) and dimethoxyethane (400 ml) were added to a 1000 ml glass reaction vessel and cooled to -70 ° C. An n-butyllithium-hexane solution (111 ml, 0.17 mol, 1.52 mol / L) was added dropwise thereto. After dropping, the mixture was stirred for 3 hours while gradually returning to room temperature. The mixture was cooled again to 70 ° C., and a dimethoxyethane solution (100 ml) containing triisopropyl borate (41 ml, 0.18 mol) was added dropwise thereto. After dropping, the mixture was stirred overnight while gradually returning to room temperature.
Distilled water (50 ml) was added to the reaction solution, and the mixture was stirred for 30 minutes, and then an aqueous solution (100 ml) of sodium carbonate 54 g, 2-bromo-4- (4-t-butylphenyl) -indene (46 g, 0.14 mol), Tetrakis (triphenylphosphino) palladium (5 g, 4.3 mmol) was added in order, and then heated while removing low boiling components and heated at 80 ° C. for 3 hours.
The reaction solution was poured into ice water (1 L), from which ether was extracted three times, and the ether layer was washed with saturated brine until neutral. Sodium sulfate was added thereto and left overnight to dry the reaction solution. Anhydrous sodium sulfate was filtered off, the solvent was distilled off under reduced pressure, the residue was purified with a silica gel column, recrystallized with hexane and 4- (4-t-butylphenyl) -2- (5-methyl-2-furyl)- Indene (30.7 g, 66% yield) was obtained as colorless crystals.

Synthesis of (1-d) dimethylbis {2- (5-methyl-2-furyl) -4- (4-t-butylphenyl) -indenyl} silane:
4- (4-t-Butylphenyl) -2- (5-methyl-2-furyl) -indene (22 g, 66 mmol) and THF (200 ml) are added to a 1000 ml glass reaction vessel and cooled to -70 ° C. did. An n-butyllithium-hexane solution (42 ml, 67 mmol, 1.60 mol / L) was added dropwise thereto. After dropping, the mixture was stirred for 3 hours while gradually returning to room temperature. The mixture was cooled again to −70 ° C., 1-methylimidazole (0.3 ml, 3.8 mmol) was added, and a THF solution (100 ml) containing dimethyldichlorosilane (4.3 g, 33 mmol) was added dropwise. After dropping, the mixture was stirred overnight while gradually returning to room temperature.
Distilled water was added to the reaction solution, transferred to a separatory funnel, and washed with brine until neutral. Sodium sulfate was added thereto and left overnight to dry the reaction solution. Anhydrous sodium sulfate was filtered off, the solvent was distilled off under reduced pressure, and the residue was purified with a silica gel column. Dimethylbis (2- (5-methyl-2-furyl) -4- (4-t-butylphenyl))-indenyl) A pale yellow solid of silane (22 g, 92% yield) was obtained.

Synthesis of (1-e) rac-dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-t-butylphenyl) -indenyl}] hafnium:
In a 500 ml glass reaction vessel, 9.6 g (13.0 mmol) of dimethylbis (2- (5-methyl-2-furyl) -4- (4-tert-butylphenyl) -indenyl) silane, 300 ml of diethyl ether. And cooled to -70 ° C in a dry ice-methanol bath. 16 ml (26 mmol) of a 1.59 mol / liter n-butyllithium-hexane solution was added dropwise thereto. After dropping, the mixture was returned to room temperature and stirred for 3 hours. The solvent of the reaction solution was distilled off under reduced pressure, 250 ml of toluene and 10 ml of diethyl ether were added, and the solution was cooled to −70 ° C. in a dry ice-methanol bath. Thereto was added 4.2 g (13.0 mmol) of hafnium tetrachloride. Thereafter, the mixture was stirred overnight while gradually returning to room temperature.
The solvent was distilled off under reduced pressure, recrystallization was performed with dichloromethane / hexane, and dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-t-butylphenyl)- Indenyl}] 1.3 g of hafnium racemate (purity 99% or more) was obtained as yellow-orange crystals (yield 22%).

The resulting proton nuclear magnetic resonance method for racemate identified value according to ^{(1 H-NMR)} are shown below.
_{^{[1 H-NMR (CDCl 3}} ) identification results:
Racemate: δ 0.95 (s, 6H), δ 1.18 (s, 18H), δ 2.09 (s, 6H), δ 5.80 (d, 2H), δ 6.37 (d, 2H), δ6. 75 (dd, 2H), δ 7.09 (d, 2H), δ 7.34 (s, 2H), δ 7.33 (d, 2H), δ 7.35 (d, 4H), δ 7.87 (d, 4H ).

[Synthesis Example 2 of Catalyst Component (A)]:
(1) Synthesis of rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium: (synthesis of component [A-1] (complex 2) ):
The synthesis of rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium is carried out according to the method described in Example 1 of JP-A-11-240909. As well as.

(2) [Catalyst Synthesis Example 1]
(2-1) Chemical treatment of ion-exchange layered silicate:
In a separable flask, 96% sulfuric acid (1044 g) was added to 3456 g of distilled water, and then 600 g of montmorillonite (Mizusawa Chemical Benclay SL: average particle size 19 μm) was added as a layered silicate. The slurry was heated to 90 ° C. over 1 hour at 0.5 ° C./minute, and reacted at 90 ° C. for 120 minutes. The reaction slurry was cooled to room temperature in 1 hour, added with 2400 g of distilled water and then filtered to obtain 1230 g of a cake-like solid.
Next, 648 g of lithium sulfate and 1800 g of distilled water were added to the separable flask to make a lithium sulfate aqueous solution, and the entire amount of the above solid on the cake was added, and 522 g of distilled water was further added. The slurry was heated to 90 ° C. over 1 hour at 0.5 ° C./minute, and reacted at 90 ° C. for 120 minutes. The reaction slurry was cooled to room temperature in 1 hour, filtered after adding 1980 g of distilled water, further washed with distilled water to pH 3, and filtered to obtain 1150 g of cake-like solid.
The obtained solid was preliminarily dried at 130 ° C. for 2 days under a nitrogen stream, and then coarse particles of 53 μm or more were removed, and further, rotary kiln drying was performed under a condition of 215 ° C. under a nitrogen stream for a residence time of 10 minutes. 340 g was obtained.
The composition of this chemically treated smectite is Al: 7.81 wt%, Si: 36.63 wt%, Mg: 1.27 wt%, Fe: 1.82 wt%, Li: 0.20 wt%, Al / Si = 0.222 [mol / mol].

(2-2) Catalyst preparation and prepolymerization:
Into a three-necked flask (volume: 1 L), 10 g of the chemically treated smectite obtained above was added, and heptane (65 mL) was added to form a slurry. To this was added triisobutylaluminum (25 mmol; 6 mL) and stirred for 1 hour, washed to 1/1000 with heptane, and heptane was added to a total volume of 100 mL.
In another flask (volume: 200 mL), rac-dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl)-] prepared in Synthesis Example 1 of the catalyst component (A) was used. 4- (4-t-butylphenyl) indenyl}] hafnium (105 μmol) is dissolved in toluene (30 mL) (solution 1), and further, the catalyst component (A) is synthesized in another flask (volume 200 mL). Rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium (45 μmol) prepared in Example 2 was dissolved in toluene (12 mL) (Solution 2 ).

After adding triisobutylaluminum (0.6 mmol: 0.83 mL of a heptane solution with a concentration of 143 mg / mL) to the 1 L flask containing the chemically treated smectite, add the above solution 1, and then add the above solution 2 after 5 minutes. And stirred at room temperature for 1 hour.
Thereafter, 356 mL of heptane was added, and this slurry was introduced into a 1 L autoclave.
After the internal temperature of the autoclave was set to 40 ° C., propylene was fed at a rate of 10 g / hour, and prepolymerization was performed while maintaining 40 ° C. for 2 hours. Thereafter, the propylene feed was stopped, the temperature was raised to 50 ° C., and residual polymerization was performed until the pressure in the autoclave reached 0.05 MPa. After removing the supernatant of the resulting catalyst slurry by decantation, triisobutylaluminum (6 mmol: 8.3 mL of a heptane solution having a concentration of 143 mg / mL) was added to the remaining portion and stirred for 5 minutes.
This solid was dried under reduced pressure for 2 hours to obtain 27.5 g of a dry prepolymerized catalyst. The prepolymerization ratio (a value obtained by dividing the amount of the prepolymerized polymer by the amount of the solid catalyst) was 1.75 (preliminary polymerization catalyst 1).

(3) [Polymerization]
After sufficiently replacing the inside of the stirring autoclave having an internal volume of 200 liters with propylene, 40 kg of sufficiently dehydrated liquefied propylene was introduced. To this was added 5 liters of hydrogen (as a standard volume) and 500 ml (0.12 mol) of a triisobutylaluminum / n-heptane solution, and the internal temperature was raised to 75 ° C. Next, 4.0 g of the prepolymerized catalyst 1 (by weight excluding the prepolymerized polymer) was injected with argon to initiate polymerization, and the internal temperature was maintained at 75 ° C. After 3 hours, 100 ml of ethanol was injected under pressure, unreacted propylene was purged, and the inside of the autoclave was purged with nitrogen to stop the polymerization in the first step.
The obtained polymer was dried for 1 hour under a nitrogen stream at 90 ° C. to obtain 14.5 kg of a polymer (PP-1). The catalytic activity was 3630 (g-PP / g-cat).
5 g of the obtained polymer was dissolved in hot xylene and then precipitated with a large amount of ethanol. After filtration, it was dried under reduced pressure to obtain a sample for analysis.

[Production Example 2] (PP-2)
The same operation as in Production Example 1 was conducted except that 6.0 liters of hydrogen was added. 15.9 kg of polymer (PP-2) was obtained. The catalytic activity was 3800 (g-PP / g-cat).

[Production Example 3] (PP-3)
The same procedure as in Production Example 1 was conducted except that 12.5 liters of hydrogen were added and 3.0 g of the prepolymerized catalyst 1 to be used (by weight excluding the prepolymerized polymer) was used. 14.3 kg of polymer (PP-3) was obtained. The catalytic activity was 4770 (g-PP / g-cat).

[Production Example 4] (PP-4)
(1) [Catalyst synthesis example 2]
In (1-2) catalyst preparation and prepolymerization in Catalyst Synthesis Example 1, rac-dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-t- Butylphenyl) indenyl}] hafnium (75 μmol) is dissolved in toluene (21 mL) to form solution 1 and rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4 —Hydroazulenyl}] Hafnium (75 μmol) was dissolved in toluene (21 mL) and used as Solution 2, and the same experiment as in Catalyst Synthesis Example 1 was performed.
As a result, 30.9 g of a dry prepolymerization catalyst (preliminary polymerization catalyst 2) was obtained. The prepolymerization ratio was 2.09 (preliminary polymerization catalyst 2).

(2) [Polymerization]
Example 1 Polymerization Example 1 except that 7.5 L (as a standard state volume) of hydrogen was introduced and 2.0 g of the prepolymerized catalyst 2 synthesized above was used instead of the prepolymerized catalyst 1 in a weight excluding the prepolymerized polymer. The same polymerization was carried out to obtain 11.4 kg of a polymer (PP-4). The catalytic activity was 5700 (g-PP / g-cat).

[Production Example 5] (PP-5)
PP-5 was performed according to Example 3 described in JP-A-2001-525460.
Into a 1 L autoclave sufficiently purged with nitrogen, 500 ml of toluene, 2.5 ml of an organoaluminum oxy compound (hexane solution manufactured by Tosoh Finechem Co., Ltd., MMAO-3A 1.47 mmol / ml) and 37.5 g of propylene were introduced and heated to 105 ° C. And left to equilibrate. Thereafter, 2.5 ml of MMAO and 1 ml of a toluene solution (1 mg / ml) of dimethylsilylene bis (2-methyl-4-phenyl-indenyl) zirconium dichloride were brought into contact with each other and activated, and the mixture was pumped to the polymerization tank with high-pressure argon. And polymerized at 105 ° C. for 15 minutes. The obtained polymer solution was added to ethanol, filtered, and dried under reduced pressure to obtain 30.5 g of polymer. The molecular weight of the polymer was Mn: 13600, Mw / Mn: 2.6, and the melting point was 142.9 ° C.

  To the 1 L autoclave, 10 g of the macromer synthesized above was charged, and the macromer was further dried by heating the autoclave to 110 ° C. while ventilating nitrogen. Thereafter, 500 ml of toluene was added and further stirred at 110 ° C. to completely dissolve the macromer. The polymerization tank was cooled, 2.5 ml of MMAO and 37.5 g of propylene were introduced, and then kept at 55 ° C. until equilibrium was reached. Thereafter, 2.5 ml of MMAO and 1 ml of a toluene solution (1 mg / ml) of dimethylsilylene bis (2-methyl-4-phenyl-indenyl) zirconium dichloride were brought into contact with each other and activated, and the mixture was pumped to the polymerization tank with high-pressure argon. And polymerized for 15 minutes. After completion of the polymerization, the polymer was recovered by filtration and dried under reduced pressure to obtain 38 g of polymer.

(Commercial goods)
PF814 (electron beam irradiated product):
High melt tension polypropylene (MFR = 2.5 g / 10 min) manufactured by Basel Co. was used.

[Example 1]
Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propione, which is a phenolic antioxidant, with respect to 100 parts by weight of the propylene polymer (PP-1). -To] methane (trade name: IRGANOX 1010, manufactured by Ciba Specialty Chemicals) 0.05 parts by weight, tris (2,4-di-t-butylphenyl) phosphite (trade name: phosphite antioxidant) IRGAFOS 168, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.05 parts by weight, and calcium stearate as a neutralizing agent (trade name: calcium stearate, manufactured by Nippon Oil & Fats Co., Ltd.) 0.05 part by weight Mix for 3 minutes at room temperature with a stirrer mixer (Henschel mixer, trade name), then melt knead with an extruder to obtain pellets It was.

Propylene system comprising 80% by weight of PP-1 obtained and 20% by weight of a commercially available propylene homopolymer (MA1B manufactured by Nippon Polypro, MFR = 20 g / 10 min, Mw 216000, λmax = 1.0, MT = 0.5 cN) Has a heating cylinder with a screw diameter of 50 mm and a mold clamping control mechanism blended with 5 parts by weight of a chemical foaming agent 30% masterbatch (Polyslen EE275F manufactured by Eiwa Kasei Co., Ltd., 40 ml / g of cracked gas) per 100 parts by weight of the resin component. Then, using an injection molding machine with a maximum clamping force of 300 tons, set the temperature of each heating zone of the heating cylinder to 230 ° C, 230 ° C, 230 ° C, 210 ° C, and 180 ° C in order from the tip to the rear. The back pressure is 9.8 MPa, the mold cooling water temperature is 40 ° C., the distance between the moving mold and the stationary mold is 2.0 mm, and the volume is 160 cm ³ . In the cavity, 160 cm ³ of the foamed molded material 160 that was heated and melted was injected and filled. The primary cooling was performed for 1 second after completion of the injection, and then the movable mold was retracted to expand the cavity volume and foam. Thereafter, secondary cooling was carried out for 20 seconds to obtain a polypropylene injection foam molded article.
Table 2 shows the evaluation results of the obtained polypropylene injection foam molding.
The polypropylene-based injection-foamed molded article satisfying the configuration of the present invention had uniform foam, good appearance of the molded product, and a high expansion ratio.

[Example 2]
It implemented similarly to Example 1 except having used the propylene polymer (PP-2) instead of the propylene polymer (PP-1), and obtained the polypropylene injection foaming molding.
Table 2 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article satisfying the configuration of the present invention had uniform foam, good appearance of the molded product, and a high expansion ratio.

[Example 3]
It implemented similarly to Example 1 except having used the propylene polymer (PP-3) instead of the propylene polymer (PP-1), and obtained the polypropylene injection foaming molding.
Table 2 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article satisfying the configuration of the present invention had uniform foam, good appearance of the molded product, and a high expansion ratio.

[Example 4]
It implemented similarly to Example 1 except having used the propylene polymer (PP-4) instead of the propylene polymer (PP-1), and obtained the polypropylene injection foaming molding.
Table 2 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article satisfying the configuration of the present invention had uniform foam, good appearance of the molded product, and a high expansion ratio.

[Example 5]
Propylene-based resin component 100 consisting of 80% by weight of PP-1 and 20% by weight of a commercially available propylene homopolymer (MA1B manufactured by Nippon Polypro, MFR = 20 g / 10 min, Mw 216000, λmax = 1.0, MT = 0.5 cN) The largest type with a heating cylinder with a screw diameter of 50 mm and a mold clamping control mechanism, blended with 5 parts by weight of a chemical foaming agent 30% masterbatch (Polyslen EE275F manufactured by Eiwa Kasei Co., Ltd., cracked gas amount 40 ml / g). Using an injection molding machine with a clamping force of 300 tons, the temperature of each heating zone of the heating cylinder was set to 230 ° C., 230 ° C., 230 ° C., 210 ° C., and 180 ° C. Cavities with a mold cooling water temperature of 40 ° C., a distance between the movable mold and the stationary mold of 2.0 mm, and a volume of 160 cm ³ The foamed molded material 65 cm ³ which was heated and melted was injected and filled in the space, and the void was filled with the expansion pressure of the foamed resin itself to obtain a polypropylene injection foamed molded product.
Table 2 shows the evaluation results of the obtained polypropylene injection foam molding.
The polypropylene injection-foamed molded article satisfying the constitution of the present invention had uniform air bubbles and good appearance of the molded product.

[Example 6]
A propylene-based resin component comprising 80% by weight of PP-1 and 20% by weight of a commercially available propylene homopolymer (MA1B manufactured by Nippon Polypro, MFR = 20 g / 10 min, Mw 216000, λmax = 1.0, MT = 0.5 cN) , Using an electric injection molding machine 850T manufactured by Ube Industries, inject 0.5 parts by weight of supercritical carbon dioxide into a resin melted at 210 ° C. at an injection pressure of 6 MPa, and inject it into a mold at a back pressure of 7 MPa. . The mold was injection-filled with 160 cm ³ of a foamed molded material, which was heated and melted, in a cavity having a cooling water temperature of 40 ° C., a distance between the moving mold and the fixed mold of 2.0 mm, and a volume of 160 cm ³ . The primary cooling was performed for 1 second after completion of the injection, and then the movable mold was retracted to expand the cavity volume and foam. Thereafter, secondary cooling was carried out for 20 seconds to obtain a polypropylene injection foam molded article.
Table 2 shows the evaluation results of the obtained polypropylene injection foam molding.
The polypropylene injection foam molded article satisfying the constitution of the present invention had uniform foam, good appearance of the molded product, and a high expansion ratio.

[Example 7]
A propylene-based resin component comprising 80% by weight of PP-1 and 20% by weight of a commercially available propylene homopolymer (MA1B manufactured by Nippon Polypro, MFR = 20 g / 10 min, Mw 216000, λmax = 1.0, MT = 0.5 cN) Using an electric injection molding machine 850T manufactured by Ube Industries Co., Ltd., injecting 0.5 parts by weight at an injection pressure of 6 MPa into a resin in which a supercritical carbon dioxide fluid is completely melted by an Amotech method at a resin temperature of 210 ° C. Injecting and filling 65 cm ³ of a foamed molded body material heated and melted into a cavity having a mold cooling water temperature of 40 ° C. under a pressure of 7 MPa, a distance between the movable mold and the fixed mold of 2.0 mm, and a volume of 160 cm ³ Then, the voids were filled with the expansion pressure of the foaming resin itself to obtain a polypropylene injection foam molded article.
Table 2 shows the evaluation results of the obtained polypropylene injection foam molding.
The polypropylene injection-foamed molded article satisfying the constitution of the present invention had uniform air bubbles and good appearance of the molded product.

[Comparative Example 1]
The same procedure as in Example 1 was carried out except that a propylene polymer (PF814) different from the propylene polymer specified in the present invention was used instead of the propylene polymer (PP-1). A foamed molded product was obtained.
Table 3 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article that does not satisfy the configuration of the present invention had a poor foam appearance although the foaming ratio was high.

[Comparative Example 2]
The same procedure as in Example 6 was carried out except that a propylene polymer (PF814) different from the propylene polymer specified in the present invention was used instead of the propylene polymer (PP-1). A foamed molded product was obtained.
Table 3 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article that does not satisfy the configuration of the present invention had a poor foam appearance although the foaming ratio was high.

[Comparative Example 3]
In the same manner as in Example 1 except that a propylene polymer (PP-5) different from the propylene polymer specified in the present invention was used instead of the propylene polymer (PP-1), polypropylene was used. A system injection foam molded article was obtained.
Table 3 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article that does not satisfy the constitution of the present invention had large and non-uniform bubbles, and the appearance of the molded product was cloudy and a swirl mark was observed.

[Comparative Example 4]
In place of the propylene polymer (PP-1), the same procedure as in Example 6 was carried out except that a propylene polymer (PP-5) different from the propylene polymer specified in the present invention was used. A system injection foam molded article was obtained.
Table 3 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article that did not satisfy the constitution of the present invention had a low expansion ratio and the appearance of the molded product was cloudy on the surface, and swirl marks were observed.

[Comparative Example 5]
Instead of the propylene polymer (PP-1) 65 cm ³ , the same procedure as in Example 7 was used except that a propylene polymer (PP-5) 100 cm ³ different from the propylene polymer specified in the present invention was used. It carried out and obtained the polypropylene-type injection foaming molding.
Table 3 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.
The polypropylene-based injection-foamed molded article that does not satisfy the constitution of the present invention has foams with extremely uneven cell coalescence, and the appearance of the molded product has no gloss.

[Example 8]
Propylene polymer (PP-1) 60% by weight and commercially available propylene ethylene block copolymer (Nippon Polypro BC04G, MFR = 40 g / 10 min, Mw 185000, λmax = 1.0, MT = 0.4 cN) 40% % Tetrapropyl [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propione, which is a phenolic antioxidant, with respect to 100 parts by weight of the propylene-based resin component G] methane (trade name: IRGANOX 1010, manufactured by Ciba Specialty Chemicals) 0.05 parts by weight, tris (2,4-di-t-butylphenyl) phosphite (trade name: IRGAFOS) which is a phosphite antioxidant 168, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.05 parts by weight, and stearin as a neutralizing agent Mixing 0.05 parts by weight of calcium (trade name: calcium stearate, manufactured by Nippon Oil & Fats Co., Ltd.), mixing for 3 minutes at room temperature with a high-speed stirring mixer (Henschel mixer, trade name), and extrusion The mixture was melt kneaded with a machine to obtain pellets.

The resulting pellet blended with 5 parts by weight of a chemical foaming agent 30% masterbatch (Polyslen EE275F manufactured by Eiwa Kasei Co., Ltd., cracked gas amount 40 ml / g) is a maximum with a heating cylinder with a screw diameter of 50 mm and a mold clamping control mechanism. Using an injection molding machine with a clamping force of 300 tons, the temperature of each heating zone of the heating cylinder is set to 230 ° C., 230 ° C., 230 ° C., 210 ° C., and 180 ° C. in order from the tip to the back. the pressure and 9.8 MPa, injection in the mold cooling water temperature 40 ° C., in the cavity space of the mobile and the fixed type and the volume at 2.0mm is 160cm ^3, the foamed molded body material 160cm ³ were heated and melted Filled. The primary cooling was performed for 1 second after completion of the injection, and then the movable mold was retracted to expand the cavity volume and foam. Thereafter, secondary cooling was carried out for 20 seconds to obtain a polypropylene injection foam molded article.
Table 4 shows the evaluation results of the obtained polypropylene injection foam molding.
The polypropylene-based injection-foamed molded article satisfying the configuration of the present invention had uniform foam, good appearance of the molded product, and a high expansion ratio.

[Example 9]
The same procedure as in Example 8 was conducted except that the propylene resin component was changed to 30% by weight of a propylene polymer (PP-1) and 70% by weight of a commercially available propylene ethylene block copolymer (BC04G). An injection foam molding was obtained.
Table 4 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Example 10]
The same procedure as in Example 8 was conducted except that the propylene resin component was changed to 10% by weight of the propylene polymer (PP-1) and 90% by weight of the commercially available propylene ethylene block copolymer (BC04G). An injection foam molding was obtained.
Table 4 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Example 11]
The propylene resin component was 60% by weight of propylene polymer (PP-1) and 40% by weight of a commercially available propylene homopolymer (MA1B, Mw 216000, λmax = 1.0, MT = 0.5cN, manufactured by Nippon Polypro). Except for this, the same procedure as in Example 8 was performed to obtain a polypropylene-based injection-foamed molded article.
Table 4 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Example 12]
The same procedure as in Example 8 was conducted except that the propylene resin component was changed to 30% by weight of the propylene polymer (PP-1) and 70% by weight of the commercially available propylene homopolymer (MA1B). A molded body was obtained.
Table 4 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Example 13]
The same procedure as in Example 8 was conducted except that the propylene resin component was changed to 10% by weight of the propylene polymer (PP-1) and 90% by weight of the commercially available propylene homopolymer (MA1B). A molded body was obtained.
Table 4 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Comparative Example 6]
The same procedure as in Example 8 was conducted, except that the propylene resin component was changed to 100% by weight of a commercially available propylene ethylene block copolymer (BC04G), to obtain a polypropylene injection foam molded article.
Table 5 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Comparative Example 7]
The same procedure as in Example 8 was conducted, except that the propylene resin component was 100% by weight of a commercially available propylene homopolymer (MA1B), to obtain a polypropylene injection foamed molded article.
Table 5 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Comparative Example 8]
The same procedure as in Example 8 was carried out except that the propylene resin component was changed to 60% by weight of a propylene polymer (PF814) and 40% by weight of a commercially available propylene ethylene block copolymer (BC04G). A molded body was obtained.
Table 5 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

[Comparative Example 9]
The same procedure as in Example 8 was conducted except that the propylene resin component was changed to 30% by weight of a propylene polymer (PF814) and 70% by weight of a commercially available propylene ethylene block copolymer (BC04G). A molded body was obtained.
Table 5 shows the evaluation results of the obtained polypropylene-based injection-foamed molded article.

式中、ＰＰ系（Ｘ）はプロピレン系重合体（Ｘ）を、ＰＰ系（Ｙ）はプロピレン系重合体（Ｙ）をそれぞれ意味する。

In the formula, PP-based (X) means propylene-based polymer (X), and PP-based (Y) means propylene-based polymer (Y).

  A molded product not containing the propylene polymer (X) could not obtain a sufficient expansion ratio (Comparative Examples 6 and 7). When 10% by weight of the propylene polymer (X) is formulated, the expansion ratio is remarkably improved, and about 70% of the expansion ratio in the 100% by weight product of the propylene polymer (X) (Example 1) can be achieved (Examples). 10, 13). On the other hand, when a commercially available high melt tension PP was formulated, the foaming ratio was significantly improved, but the appearance deteriorated (Comparative Examples 8 and 9).

  The polypropylene-based injection-foamed molded article of the present invention has good injection-foaming moldability, is excellent in foaming and bubble uniformity, surface appearance, and can be significantly reduced in weight at a high foaming ratio. Automotive interior parts such as door trims, air-conditioner cases, air cleaner cases, automotive heat-resistant parts such as lamps, automotive exterior parts such as bumpers and back doors, industrial parts such as toiletries, washstands and toiletries It is extremely useful for such applications.

Claims (7)

Propylene polymer (X) 6 to 100% by weight satisfying the following requirements (i) to (vi) and a propylene polymer having a weight average molecular weight different from propylene polymer (X) of 50,000 to 800,000 (Y) A propylene resin composition comprising 0.05 to 10 parts by weight of a foaming agent with respect to 100 parts by weight of a propylene resin component composed of 0 to 94% by weight is formed by injection foam molding. A polypropylene-based injection-foamed molded article.
Requirement (i): Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is 0.01 g / 10 min or more and 100 g / 10 min or less.
Requirement (ii): The ratio (Q value) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 3.5 or more and 10.5 or less.
Requirement (iii): In the molecular weight distribution curve obtained by GPC, the ratio of the component having a molecular weight (M) of 2 million or more to the total amount is 0.4% by weight or more and less than 10% by weight.
Requirement (iv): In temperature rising elution fractionation (TREF) with orthodichlorobenzene (ODCB), the component eluted at a temperature of 40 ° C. or less is 3.0% by weight or less.
Requirement (v): The isotactic triad fraction (mm fraction) measured by 13C-NMR is 95% or more.
Requirement (vi): The strain hardening degree (λmax) in the measurement of elongational viscosity is 6.0 or more. The polypropylene-based injection-foamed molded article according to claim 1, wherein the propylene-based polymer (X) further satisfies the following requirement (vii).
Requirement (vii): ME (memory effect) satisfies the following relational expression.
(ME) ≧ −0.26 × log (MFR) +1.9
[In the formula, ME (memory effect) uses a melt indexer with an orifice of 8.00 mm in length and a diameter of 1.00 mmφ, sets the temperature in the cylinder to 190 ° C., applies a load, and the extrusion speed is 0 At 1 g / min, the polymer extruded from the orifice is quenched in ethanol, and the strand diameter of the extrudate is divided by the orifice diameter. ] The propylene-based polymer (X) further satisfies the following requirement (viii): The polypropylene-based injection-foamed molded product according to claim 1 or 2.
Requirement (viii): In the molecular weight distribution curve obtained by GPC, the common logarithm of the molecular weight corresponding to the peak position is Tp, and the common logarithm of the molecular weight at the position where the peak height is 50% is L ₅₀ and H ₅₀ (L ₅₀ Is lower molecular weight than Tp, H ₅₀ is higher molecular weight than Tp), and α and β are defined as α = H ₅₀ −Tp and β = Tp−L ₅₀ , respectively, α / β is larger than 0.9 , Less than 2.0.   The said foaming agent is at least 1 type chosen from a chemical foaming agent or a physical foaming agent, The polypropylene-type injection-foaming molding of any one of Claims 1-3 characterized by the above-mentioned. A method for producing the polypropylene-based injection foam molding according to any one of claims 1 to 4 by an injection foam molding method,
An injection step of injecting and filling the propylene-based resin composition into a mold cavity in a molten state or a semi-molten state; and a foaming step of foaming the propylene-based resin composition in the mold cavity. A method for producing a polypropylene-based injection-foamed molded article.   The injection foam molding method includes an injection step of injecting and filling a mold cavity with a molten or semi-molten propylene resin composition in an amount less than the volume of the mold cavity, and an expansion pressure by a foaming agent. The method for producing a polypropylene-based injection-foamed molded article according to claim 5, which is a short shot method comprising a foaming step of filling the voids.   In the injection foam molding method, the mold is composed of a fixed mold and a movable mold capable of moving forward and backward, and a mold cavity clearance smaller than the mold cavity clearance (t1) corresponding to the shape position of the final product. An injection step of injecting and filling a molten or semi-molten propylene-based resin composition into a mold cavity having (t0), and retracting the movable mold to the mold cavity clearance (t1), and by an expansion pressure by a foaming agent The method for producing a polypropylene-based injection-foamed molded article according to claim 5, which is a mold-opening injection molding method comprising a foaming step for filling a void in a mold cavity.

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