JP2019151858A - Manufacturing method of polypropylene resin foam molding material and molded body - Google Patents

Abstract

To provide a polypropylene resin composition for providing a foam molded body having uniform fine foam cells, good in extendability, and having improved surface appearance of the molded body, a foam sheet, and a molded product by heat molding using the same.SOLUTION: There is provided a polypropylene resin composition for foam molding containing polypropylene (X) of 10 to 99 wt.% ad a propylene block copolymer (Y) of 1 to 90 mass%, and having melting tension measured at 230°C (MT) of 1 g or more, and the number of gel with longer diameter of 0.5 mm or more when making a non-oriented film with thickness of 25 μm of 50/mor less.SELECTED DRAWING: None

Description

  The present invention relates to a polypropylene resin composition for foam molding, and more specifically, gives a film having a very small number of gels per unit area, has a high closed cell ratio, is dense, and has a uniform size. In addition, the present invention relates to a foam molded article or foam sheet produced using the resin composition, and the foam molded article or foam sheet was thermoformed. For molded products.

One of the important molding methods for polypropylene is foam molding. Various molded products obtained by extrusion foaming and injection foaming have excellent properties such as heat insulation, sound insulation, cushioning and energy absorption, and are used in a wide range of applications. In recent years, in particular, from the viewpoint of environmental problems, weight reduction of materials and reduction of environmental burden have become important development factors, and further improvement of foaming characteristics is desired for the resin as a raw material. .
In general, polypropylene has a linear molecular structure and a standard molecular weight distribution, and thus has low melt tension and is difficult to perform foam molding. In order to compensate for this drawback, various technological developments have been made in the past as methods for improving the melt tension of polypropylene.
One of the representative methods is a method of introducing a long chain branch by generating a radical. Long-chain branching refers to a branched structure with molecular chains having several tens or more main chain carbon atoms and several hundreds or more in molecular weight, and is considered to have an effect of improving melt tension. As specific methods, a method using high-energy ionizing radiation (see Patent Document 1), a method using organic peroxide (see Patent Document 2), and the like are disclosed.
However, the method using high energy ionizing radiation requires special equipment for using the radiation, and the manufacturing cost is inevitably high. In addition, because radicals generated by high-energy ionizing radiation remain, problems such as yellowing occur, and quality problems such as changes in physical properties over time and unstableness. ing. In addition, the method using organic peroxide has quality problems such as contamination, odor, and yellowing due to decomposition products of organic peroxide, and the organic oxide is unstable. There is a big problem in terms of safety at the time.

As another method for improving the melt tension of polypropylene, there is a method of introducing an extremely high molecular weight component. Specific methods include a method of producing an ultrahigh molecular weight component by multistage polymerization (see Patent Documents 3 and 4), a method of producing an ultrahigh molecular weight polyethylene component by preliminary polymerization (see Patent Document 5), and the like. It has been.
However, the polypropylene produced by such a method has a much lower melt tension than polypropylene having a long chain branch, and therefore the foaming properties are not satisfactory and the applicable range is limited. I have a problem.
In order to solve such problems and problems, development of a technique for forming a long chain branch without generating a radical has been advanced (see Patent Documents 6 to 9). In this technique, a macromonomer having a terminal unsaturated bond is produced by polymerizing a monomer using a metallocene catalyst having a specific structure, and copolymerized with propylene to form a long chain branch. By these methods, problems such as odor caused by radical generation could be solved. Even if it can be made high, even if the cell formation during foaming is good, the spreadability is low, so the cell breaks down during sheet formation, the appearance of the sheet surface deteriorates, or the fluidity becomes low There is a problem that the extrusion rate cannot be increased and productivity is deteriorated. In particular, it is a big problem that the formation of foamed cells and the prevention of cell breakage at the time of spreading cannot be achieved at a high extrusion rate and a high molding speed.

From the viewpoint of developing a resin composition suitable for foam molding, a method of blending a plurality of polypropylenes (see Patent Documents 10 to 14) is disclosed.
However, although the patent documents 10 to 14 disclose blends of various polypropylenes, it is difficult to say that sufficient foaming characteristics are obtained. In particular, there is no improvement for the problems such as insufficient melt tension, insufficient fluidity, and poor appearance that occur when introducing long-chain branches using a macromonomer. To reduce the cost.

  Under such circumstances, when the polypropylene resin is foam-molded, the present inventors further adhere the film to the surface of the molded body immediately after foam molding or by post-processing if the surface of the foam-molded body is significantly uneven. However, there are problems such as difficulty in adhesion and peeling of the film (= delamination), and even if you try to print directly on the surface of the product, the printing will be bad and the design will be reduced. There was a strong call for improvement of the defect.

Japanese Patent Laid-Open No. 62-121704 JP 2001-524565 A WO99 / 077752 JP 2001-335666 A WO97 / 14725 publication JP-T-2001-525460 JP 2009-275207 A JP 2009-293020 A JP 2009-299029 A JP 2001-226510 A JP 2002-356573 A JP 2010-121054 A JP 2009-275210 A JP 2011-068819 A JP 2013-199643 A Japanese Patent Laying-Open No. 2015-040213

  An object of the present invention is to provide a polypropylene resin composition having a high melt tension which can be suitably used for various moldings and has excellent physical properties of the product obtained in view of the current state of the prior art. In particular, in the field of foam molding, a polypropylene resin composition for obtaining a foam molded article having uniform and fine foam cells, good spreadability, and improved surface appearance of a molded article is provided and used. Another object is to provide a foamed sheet and a molded product thermoformed using the foamed sheet.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have reduced the number of gels of a specific size measured under a predetermined condition to a certain value or less, thereby performing such foam molding. It was found that the surface appearance of the foamed molded article prepared using the polypropylene resin composition for use was kept good, and the present invention was completed based on this finding.
In addition, regarding the relationship between the number of gels of a specific size measured under predetermined conditions in the polypropylene resin composition for foam molding and the surface appearance of the foam molded article, there is no description or suggestion in the publicly known literature. I want to state that it is not done.

That is, the present invention includes the following inventions.
[1] It contains 10 to 99% by weight of polypropylene (X) and 1 to 90% by weight of propylene-based block copolymer (Y), has a melt tension (MT) measured at 230 ° C. of 1 g or more, and has a thickness of 25 μm. A polypropylene resin composition for foam molding in which the number of gels having a major axis of 0.5 mm or more is 50 / m ² or less when an unstretched film is formed.
[2] The polypropylene resin composition for foam molding according to [1], wherein the number of gels having a major axis of 0.4 mm or more and less than 0.5 mm is 400 / m ² or less when an unstretched film having a thickness of 25 μm is used.
[3] When an unstretched film having a thickness of 25 μm is used, the number of gels having a major axis of 0.4 mm or more and less than 0.5 mm is 400 / m ² or less, and the number of gels having a major axis of 0.3 mm or more and less than 0.4 mm is included. The polypropylene resin composition for foam molding according to [1], which is 2000 pieces / m ² or less.
[4] The polypropylene resin composition for foam molding according to any one of [1] to [3], wherein a melt tension (MT) measured at 230 ° C. is 3 g or more.
[5] The polypropylene resin composition for foam molding according to any one of [1] to [4], wherein the melt tension (X) measured at 230 ° C. of the polypropylene (X) is 3 g or more.
[6] The polypropylene resin composition for foam molding according to any one of [1] to [4], wherein the polypropylene (X) satisfies the following characteristics (Xi) to (X-iv).
Characteristic (Xi): Long chain branching.
Characteristic (X-ii): Melt tension (MT) measured at 230 ° C. is 3 to 25 g.
Characteristic (X-iii): Melt flow rate (MFR) is more than 0.9 g / 10 min and not more than 15 g / 10 min.
Characteristic (X-iv): 25 degreeC xylene soluble component amount (CXS) is less than 5 wt% with respect to polypropylene (X) whole quantity.
[7] Propylene (co) polymer (Y-1) in which the propylene-based block copolymer (Y) may contain 10% by weight or less of a comonomer and propylene having an ethylene content of 11.0 to 38.0% by weight -It consists of an ethylene copolymer (Y-2), and when the total amount of the propylene-based block copolymer (Y) is 100 wt%, (Y-1) is 50 to 99 wt%, and (Y-2) is 1 to 1. The polypropylene resin composition for foam molding according to any one of [1] to [6], which is 50% by weight.
[8] The polypropylene resin composition for foam molding according to [7], wherein the propylene-based block copolymer (Y) is produced by sequential polymerization.
[9] Foam made of polypropylene (X) having a melt tension (230 ° C.) of 3 g or more and an unstretched film having a thickness of 25 μm and having a major axis of 0.5 mm or more and a number of gels of 10 pieces / m ² or less. Polypropylene resin for molding.
[10] The polypropylene resin for foam molding according to [9], wherein the number of gels having a major axis of 0.2 mm or more and less than 0.5 mm is 50 / m ² or less when an unstretched film having a thickness of 25 μm is used.
[11] When an unstretched film having a thickness of 25 μm is used, the number of gels having a major axis of 0.2 mm or more and less than 0.5 mm is 50 / m ² or less, and the number of gels having a major axis of 0.1 mm or more and less than 0.2 mm is included. The polypropylene resin for foam molding according to [9], which is 100 pieces / m ² or less.
[12] The polypropylene resin for foam molding according to any one of [9] to [11], wherein the polypropylene (X) satisfies the following characteristics (Xi) to (X-iv).
Characteristic (Xi): Long chain branching.
Characteristic (X-ii): Melt tension (MT) measured at 230 ° C. is 3 to 25 g.
Characteristic (X-iii): Melt flow rate (MFR) is more than 0.9 g / 10 min and not more than 15 g / 10 min.
Characteristic (X-iv): 25 degreeC xylene soluble component amount (CXS) is less than 5 wt% with respect to polypropylene (X) whole quantity.
[13] 100 parts by weight of the polypropylene resin composition for foam molding according to any one of [1] to [8] or the polypropylene resin for foam molding according to any one of [9] to [12] On the other hand, a polypropylene resin foam molding material containing 0.05 to 6.0 parts by weight of a foaming agent.
[14] A polypropylene resin foam molded article obtained by extruding the polypropylene resin foam molding material according to [13].
[15] A polypropylene resin laminated foam molded article obtained by co-extrusion of the polypropylene resin foam molded article according to [14] and a non-foamed layer made of a thermoplastic resin composition.
[16] The polypropylene resin laminated foam molded article according to [15], wherein the thermoplastic resin composition contains 50 parts by weight or less of an inorganic filler with respect to 100 parts by weight of the thermoplastic resin.
[17] A molded product obtained by thermoforming the polypropylene resin foam molded article or laminated foam molded article according to any one of [14] to [16].
[18] A molded product obtained by subjecting the polypropylene resin foam molding material according to [13] to any one of injection molding, thermoforming, blow molding or bead foam molding.
[19] The molded body according to any one of [14] to [16], which is a sheet.
[20] A foam sheet of the polypropylene resin composition for foam molding according to any one of [1] to [8] or the polypropylene resin for foam molding according to any one of [9] to [12]. Use for manufacturing.

The polypropylene resin composition for foam molding of the present invention has a very uniform cell formation during foam molding even under conditions where the extrusion rate is high and the molding speed is high. A foamed molded product having cells can be produced. In addition, it is possible to produce a foam sheet having a very high fluidity and spreadability and a beautiful appearance at a high extrusion rate. Moreover, while having such a high foaming characteristic, it has excellent draw-down resistance and good thermoformability.
The foamed molded body thus obtained has excellent appearance, thermoformability, impact resistance, lightness, rigidity, heat resistance, heat insulation, oil resistance, etc. It can be suitably used for vehicle interior materials such as food containers, automobile door trims, and automobile trunk mats, packaging, stationery, and building materials.

It is a figure explaining the conceptual diagram of CFC-FT-IR.

  Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example of the embodiments of the present invention, and the present invention is not limited to the following unless it exceeds the gist. The description is not limited.

The polypropylene resin composition for foam molding of the present invention (hereinafter sometimes referred to as a resin composition) comprises 10 to 99 wt% of polypropylene (X) and 1 to 90 wt% of a propylene-based block copolymer (Y). It is characterized by containing. It is preferable that the polypropylene (X) and the propylene-based block copolymer (Y) satisfy specific requirements and specific physical properties.
Below, polypropylene (X), a propylene-type block copolymer (Y), and the characteristic which they satisfy | fill are described in detail for every item.

I. Polypropylene (X)
The polypropylene (X) used in the present invention may be a propylene homopolymer or a propylene copolymer. In the case of a propylene copolymer, the comonomer is at least one olefin selected from the group consisting of ethylene and an α-olefin having 4 to 10 carbon atoms, and the content of the comonomer in polypropylene (X) is 3 wt% or less. It is. The polypropylene (X) of the present invention is preferably a propylene homopolymer because of its high heat resistance and rigidity.

Preferably, the polypropylene (X) in the present invention satisfies the following properties (X-i) to (X-iv).
Characteristic (Xi): Long chain branching.
Characteristic (X-ii): Melt tension (MT) measured at 230 ° C. is 3 to 25 g.
Characteristic (X-iii): Melt flow rate (MFR) is more than 0.9 g / 10 min and not more than 15 g / 10 min.
Characteristic (X-iv): 25 degreeC xylene soluble component amount (CXS) is less than 5 wt% with respect to polypropylene (X) whole quantity.

Among such polypropylenes (X), those satisfying the following characteristics (X-v) are more preferable, and those satisfying the following characteristics (X-vi) are most preferable.
Characteristic (Xv): The branching index g ^{′ at an} absolute molecular weight Mabs of 1 million is 0.3 or more and less than 1.0.
Characteristic (X-vi): Strain hardening degree (λmax) in measurement of extensional viscosity is 5-15.
Details will be described in order below.

I-1. Characteristic (Xi): Long chain branching Preferably, the polypropylene (X) according to the present invention has long chain branching. Long-chain branching refers to a branched structure of a molecular chain consisting of several tens or more main chain carbon atoms and several hundred or more in molecular weight, and the number of carbons formed by copolymerization with an α-olefin such as 1-butene. Is distinguished from several short chain branches.
There are several methods for examining whether or not there is long-chain branching in polypropylene, but the one based on the rheological characteristics of the resin as shown in the characteristics (X-ii) (X-vi) can be easily used. As a more rigorous identification method, there are a method using the relationship between molecular weight and viscosity, a method using ¹³ C-NMR, etc., as shown in the feature (Xv). Regarding the latter, Patent Document 7 and Macromol. Chem. Phys. 2003, vol. Refer to 204 and 1738 for detailed explanation.

I-2. Characteristic (X-ii): Melt tension (MT)
Preferably, the polypropylene (X) according to the present invention has a melt tension (MT) of 3 to 25 g as shown in the characteristic (X-ii). The melt tension (MT) in the present invention is a value measured under the following conditions.

[MT measurement conditions]
Measuring device: Capillograph 1B manufactured by Toyo Seiki Seisakusho Co., Ltd.
Capillary: 2.0mm diameter, 40mm length
Cylinder diameter: 9.55mm
Piston extrusion speed: 20 mm / min Take-up speed: 4.0 m / min (However, if MT is too high and the resin breaks, the take-up speed is lowered and the maximum take-up speed is measured.)
Temperature: 230 ° C

Melt tension (MT) is recognized as an important factor for foam molding, and many patent documents specify MT.
For example, Patent Document 7 discloses a propylene polymer having high MT and swell and excellent moldability. Regarding MT, there is a description of a preferable range in paragraph [0078], and the higher the better, the most preferable being 15 g or more. Therefore, there is no description in Patent Document 7 that suggests a specific MT value that is preferable in the present invention, and for the polypropylene having a long chain branch, the present invention that MT is relatively preferable from 3 g or higher Are fundamentally different in technical idea of the invention.
Patent Documents 8 and 9 disclose an extrusion foam molding resin composition and a polypropylene foam sheet, respectively. Descriptions relating to MT are described in paragraphs [0074] and [0076], respectively.
Patent Document 10 discloses a polypropylene resin foam produced by extrusion foaming using a mixture of a high MT polypropylene having a long chain branch and a low MT polypropylene. In this case as well, there is a detailed description in paragraph [0014], but it is described that MT is preferably higher, and there is no description that suggests a specific MT value that is preferable in the present invention.
Further, Patent Document 11 discloses a polypropylene resin extruded foam sheet in which a base resin is a mixture of a high MT polypropylene resin and a low MT polypropylene resin. Examples of high MT polypropylene resins are described in paragraph [0015], and have long chain branching or crosslinking, but as defined in claim 1 of the claims, MT is 10 cN or more. The higher description is preferable (1 g = 0.98 cN), and there is no description suggesting a specific MT value preferable in the present invention.
In addition, Patent Document 12 includes a low MFR polypropylene, a specific prescribed propylene / ethylene block copolymer, a polypropylene containing an olefin polymer having a very high intrinsic viscosity, and hydrogenation of a styrene / conjugated diene block copolymer. A polypropylene resin composition comprising a thermoplastic resin such as a product is disclosed. Although a polypropylene containing an olefin polymer having a very high intrinsic viscosity corresponds to a high MT polypropylene, this Patent Document 12 suggests a description regarding a long-chain branched polypropylene having a specific MT value preferable in the present invention. Nothing at all. In addition, the polypropylene containing the olefin polymer having an extremely high intrinsic viscosity disclosed in Patent Document 12 is difficult to disperse the olefin polymer having an extremely high intrinsic viscosity, the bright spot is poor, and the appearance of the molded product tends to be deteriorated. It also includes such problems.
Furthermore, Patent Document 13 discloses a polypropylene-based expanded foam film obtained by stretching a propylene resin composition comprising a polypropylene having a long chain branch, a propylene-based polymer, and a foaming agent in at least one direction. Yes. Also in this case, as described in paragraph [0072], higher MT is preferable, and there is no description suggesting a specific MT value preferable in the present invention.

Preferably, the polypropylene (X) according to the present invention has an MT of 3 to 25 g. About the minimum of MT, it is preferable that MT is 3 g or more. Thereby, the tension | tensile_strength which does not break in the case of foam cell formation is maintained, the raise of an open cell rate can be suppressed, a cell diameter can be kept small, and cell size can be made uniform. As for the upper limit of MT, MT is preferably 24 g or less, more preferably MT is 20 g or less, and most preferably 15 g or less. Thereby, the spreadability at the time of extrusion molding can be improved, the appearance of a sheet, a film, a molded body, and the like can be improved, bubble breakage due to poor spread can be prevented, and an increase in the open cell ratio can be suppressed.
Specific methods for controlling MT within the above range include a method for changing the number of long chain branches by adjusting the catalyst production method (particularly, the loading ratio of the complex), and within the range of characteristics (X-iii). There is a method for adjusting the MFR. Increasing the number of long chain branches or lowering MFR increases MT. On the other hand, the MT may be adjusted in the opposite direction to reduce the MT.

I-3. Characteristic (X-iii): MFR
Preferably, the polypropylene (X) according to the present invention has an MFR of more than 0.9 g / 10 minutes and not more than 15 g / 10 minutes as shown in the above property (X-iii).
MFR in the present invention is A method, condition M (230 ° C., 2.16 kg load) of JIS K7210: 1999 “Plastics—Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics”. It is a value measured according to.

MFR is the most basic factor in polypropylene molding. In the case of foam molding or extrusion molding, it is generally said that a relatively low value is preferred.
For example, in Patent Document 7, there is a description of a preferable range in paragraph [0037] of MFR, and it is described that a relatively low value is preferable in the case of extrusion foam molding, and the most preferable range is 1. It is described as 0 to 3.0 g / 10 min. Accordingly, Patent Document 7 does not include any description suggesting a specific MFR value that is preferable in the present invention, and is different from the present invention in which more than 0.9 g / 10 min and 15 g / 10 min or less are preferable. .
Moreover, in the said patent documents 8 and 9, although the description regarding MFR exists in a paragraph [0035] and [0037], respectively, it is described that a comparatively low value is preferable like the said patent document 7, and is the most preferable. The range is stated as 2-5 g / 10 min. Therefore, both patent documents do not have any description suggesting a specific MFR value that is preferable in the present invention.
Further, in Patent Document 10, there is no description regarding MFR in the detailed description, but the values (MI) of the examples are 1.8 and 3.0 g / 10 minutes (paragraph [0030]). There is no statement suggesting a preferred specific MFR value.
Moreover, in the said patent document 11, although there exists description about the MFR ratio of a high MT polypropylene resin and a low MT polypropylene resin, there is no detailed description regarding the value of MFR itself. The MFR value in the examples is 3.2 g / 10 min (paragraph [0052]), and there is no description suggesting a specific MFR value that is preferable in the present invention.
Moreover, in the said patent document 12, although the polypropylene containing the olefin polymer which has very high intrinsic viscosity corresponds to the polypropylene of high MT, the detailed description regarding the MFR exists in the paragraph [0047], and the most preferable range is It is described as 0.2 to 5.0 g / 10 min. In this patent document, there is no description suggesting a long-chain branched polypropylene having a specific MFR value preferable in the present invention.
Further, in the case of Patent Document 13, as described in paragraph [0034], the MFR is preferably low, and the most preferable range is described as 2 to 5 g / 10 min. There is no statement suggesting specific MFR values preferred in the present invention.

Preferably, the polypropylene (X) according to the present invention has an MFR of more than 0.9 g / 10 minutes and 15 g / 10 minutes or less. Regarding the lower limit of MFR, it is preferably 1 g / 10 min or more, more preferably 1.2 g / 10 min or more, and most preferably 1.5 g / 10 min or more. Thereby, the spreadability at the time of extrusion molding can be improved, the appearance of a sheet, a film, a molded body, and the like can be improved, bubble breakage due to poor spread can be prevented, and an increase in the open cell ratio can be suppressed. The upper limit of MFR is preferably 14 g / 10 min or less, more preferably 13 g / 10 min or less, still more preferably 12 g / 10 min or less, and most preferably 10 g / 10 min or less. Thereby, generation | occurrence | production of the part extended excessively at the time of foam cell formation can be suppressed, the raise of the open cell rate by bubble breaking can be prevented, a cell diameter can be kept small, and cell size can be made uniform.
As a specific method for adjusting the MFR to the above range, a method of changing the amount of hydrogen added during polymerization can be mentioned. Since hydrogen acts as a chain transfer agent in the polymerization of propylene, if the amount of hydrogen added is increased, the MFR increases. Conversely, if the amount added is decreased, the MFR can be decreased. The value of MFR relative to the hydrogen concentration inside the polymerization tank varies depending on the catalyst used and other polymerization conditions, but the relationship between the hydrogen concentration and MFR is determined in advance according to the catalyst type and other polymerization conditions, and the desired MFR value is determined. It is very easy for those skilled in the art to adjust the hydrogen concentration so as to obtain a value.

I-4. Characteristic (X-iv): 25 ° C. xylene-soluble component amount (CXS)
Preferably, the polypropylene (X) according to the present invention has a 25 ° C. xylene-soluble component amount (CXS) of less than 5 wt% as shown in the above property (X-iv) (provided that the total amount of polypropylene (X) is 100 wt%). CXS in the present invention is a value measured by the following procedure.

[CXS measurement procedure]
A 2 g sample is dissolved in 300 ml of p-xylene (containing 0.5 mg / ml BHT) at 130 ° C. to make a solution, and then left at 25 ° C. for 12 hours. Thereafter, the precipitated polymer is separated by filtration, p-xylene is evaporated from the filtrate, and further dried under reduced pressure at 100 ° C. for 12 hours to recover a 25 ° C. xylene-soluble component. The ratio [wt%] of the weight of the recovered component to the charged sample weight is defined as CXS.

CXS is a general index representing a low-crystalline polymer component, and by setting this value below a predetermined value, the content of the low-crystalline component in polypropylene (X) becomes high, and at the time of molding or product It is possible to suppress the occurrence of problems in itself. For example, it is possible to suppress the occurrence of a problem of eye smoke or smoke during extrusion foam molding, or the problem of stickiness of the surface of a sheet, film, or product. Preferably, the polypropylene (X) according to the present invention has a CXS of less than 5 wt%. CXS is preferably less than 3 wt%, more preferably less than 1 wt%, and most preferably less than 0.5 wt%. Although there is no restriction | limiting in particular about the lower limit of CXS, Preferably it is 0.01 wt% or more, More preferably, when it is 0.05 wt% or more, the effect of an additive will become easy to express.
As a specific method for adjusting CXS to the above range, a catalyst can be selected. The most important factor for determining CXS of polypropylene having a long chain branch is a catalyst, and a catalyst satisfying CXS may be selected from known catalysts. Specific examples of the catalyst will be described later.

I-5. Characteristic (Xv): Branch index g ^′
Preferably, the polypropylene (X) according to the present invention satisfies the characteristics (Xi) to (X-iv), but preferably satisfies the following characteristics (Xv).
Characteristic (Xv): The branching index g ^{′ at an} absolute molecular weight Mabs of 1 million is 0.3 or more and less than 1.0.

The branching index g ^′ is known as a more direct indicator for long chain branching. There is a detailed description in “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983). The definition of the branching index g ^′ is as follows.
Branch index g ^′ = [η] br / [η] lin
[Η] br: Intrinsic viscosity of polymer (br) having a long chain branched structure [η] lin: Intrinsic viscosity of linear polymer having the same molecular weight as polymer (br)

As is clear from the above definition, when a long chain branching structure exists, the branching index g ^′ takes a value smaller than 1, and the value of the branching index g ^′ decreases as the long chain branching structure increases. Since polypropylene generally has a molecular weight distribution, if a long-chain branched structure exists in a component having a considerably large molecular weight, it can efficiently promote entanglement and contribute to enhancing foaming characteristics. Therefore, among the polypropylenes (X) according to the present invention, those in which the value of the branching index g ^′ when the absolute molecular weight Mabs is 1 million are in a specific range are particularly preferable.
In order to know the value of the branching index g ^′ when the absolute molecular weight Mabs is 1 million, the value of the branching index g ^′ must be obtained as a function of the absolute molecular weight Mabs. Regarding this point, the following measurement method, analysis method, and calculation method are used in the present invention.

[Measuring method]
GPC: Alliance GPCV2000 (Waters)
Detector: Described in the order of connection Multi-angle laser light scattering detector (MALLS): DAWN-E (Wyatt Technology)
Differential refractometer (RI): attached to GPC Viscometer (Viscometer): attached to GPC Mobile phase solvent: 1,2,4-trichlorobenzene (Irganox 1076 added at a concentration of 0.5 mg / mL)
Mobile phase flow rate: 1 mL / min Column: Tosoh Corporation GMHHR-H (S) Two HT connections Sample injection part temperature: 140 ° C.
Column temperature: 140 ° C
Detector temperature: 140 ° C for all
Sample concentration: 1 mg / mL
Injection volume (sample loop volume): 0.2175 mL

[analysis method]
When calculating the absolute molecular weight (Mabs) obtained from the multi-angle laser light scattering detector (MALLS), the root mean square radius of inertia (Rg), and the intrinsic viscosity ([η]) obtained from the Viscometer, data processing attached to MALLS Calculation is performed using the software ASTRA (version 4.73.04) with reference to the following document.
References:
1. “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983. Chapter 1.)
2. Polymer, 45, 6495-6505 (2004).
3. Macromolecules, 33, 2424-2436 (2000)
4). Macromolecules, 33, 6945-6952 (2000)

[Calculation method of branching index g ′]
The branching index g ′ is a ratio of the intrinsic viscosity ([η] br) obtained by measuring a sample with the above Viscometer and the intrinsic viscosity ([η] lin) obtained separately by measuring a linear polymer ([[ η] br / [η] lin).
Here, as a linear polymer for obtaining [η] lin, a commercially available homopolypropylene (Novatec PP (registered trademark) grade name: FY6 manufactured by Nippon Polypro Co., Ltd.) is used. It is known as a Mark-Houwink-Sakurada formula that the logarithm of [η] lin of a linear polymer has a linear relationship with the logarithm of molecular weight, and [η] lin is The values are obtained by extrapolation as appropriate.

The polypropylene (X) according to the present invention preferably has a branching index g ^′ of 0.3 or more and less than 1.0 when the absolute molecular weight Mabs is 1,000,000. More preferably, they are 0.55 or more and 0.98 or less, More preferably, they are 0.75 or more and 0.96 or less, Most preferably, they are 0.78 or more and 0.95 or less.
When the branching index g ′ is in the above range, the degree of decrease in melt tension when kneading is repeated is small, and therefore the decrease in physical properties and moldability during material recycling in the production process is preferably small.
As a specific method for adjusting the branching index g ′ within the above range, a catalyst can be selected. The most important factor for determining the branching index g ′ of polypropylene having a long chain branch is a catalyst, and a catalyst satisfying the branching index g ′ may be selected from known catalysts. Specific examples of the catalyst will be described later.

I-6. Characteristic (X-vi): strain hardening degree (λmax) in measurement of extensional viscosity
Preferably, the polypropylene (X) according to the present invention satisfies the above-mentioned characteristics (X-i) to (X-iv), and preferably satisfies the characteristics (X-v). It is preferable to satisfy the characteristic (X-vi).
Characteristic (X-vi): Strain hardening degree (λmax) in measurement of extensional viscosity is 5-15.

In the calculation of λmax in the present invention, the value of extensional viscosity measured under the following conditions is used.
Apparatus: Ales manufactured by Rheometrics
Jig: EXTENSIONAL VISUALITY FIXTURE, manufactured by TA Instruments
Measurement temperature: 180 ° C
Strain rate: 0.1 / sec
Test piece preparation method: Press molding Test piece shape: Sheet of 18 mm x 10 mm, thickness 0.7 mm

Next, a method for calculating λmax from the obtained value of extensional viscosity will be described.
First, the time t (second) is plotted on the horizontal axis and the elongational viscosity η _E (Pa · second) is plotted on the logarithmic graph on the vertical axis, and the viscosity immediately before strain hardening is approximated by a straight line on the logarithmic graph. Specifically, first, the slope at each time when the extensional viscosity is plotted against time is obtained. In this case, considering the fact that the measurement data of the extensional viscosity is discrete, the slope of the adjacent data is obtained. Is used, and a moving average of several surrounding points is used.
The elongational viscosity is a simple increasing function in the low strain region, gradually approaches a constant value, and if there is no strain hardening, it agrees with the Truton viscosity after a sufficient amount of time. From about 1 strain amount (= strain rate × time), the extensional viscosity starts to increase with time. That is, the slope tends to decrease with time in the low strain region, but tends to increase from about 1 strain, and there is an inflection point on the curve when the extensional viscosity is plotted against time. . Therefore, a point where the slope of each time obtained above takes the minimum value in the range of the distortion amount of about 0.1 to 2.5 is obtained, and a tangent line is drawn at the point, and the straight line has a distortion amount of 4.0. Extrapolate until The maximum value (ηmax) of the extensional viscosity η _E until the strain amount becomes 4.0 is obtained, and the viscosity on the approximate straight line up to that time is η lin. ηmax / ηlin is defined as λmax (0.1).

The degree of strain hardening (λmax) is also recognized as an important factor for foam molding, and many patent literatures specify the degree of strain hardening.
For example, in Patent Document 7, regarding the degree of strain hardening (λmax), there is a description of a preferable range in paragraph [0066] in addition to claim 1 of the scope of claims. Is referred to as 15.0 or higher. Therefore, in Patent Document 7, there is no description that suggests a value of a specific degree of strain hardening (λmax) that is preferable in the present invention, and it is preferable that relatively low 5 to 15 is preferable as polypropylene having a long chain branch. The technical idea of the invention is fundamentally different from the invention.
Further, in Patent Documents 8 and 9, the descriptions regarding the strain hardening degree (λmax) are in paragraphs [0061] and [0063], respectively. There is no description suggesting the value of strain hardening degree (λmax).
In addition, Patent Document 12 does not include any suggestion regarding a long-chain branched polypropylene having a specific strain hardening degree (λmax) value that is preferable in the present invention.
Further, in the case of Patent Document 13, as described in paragraph [0059], it is preferable that the degree of strain hardening (λmax) is high, and a description suggesting a specific value of degree of strain hardening (λmax) that is preferable in the present invention. There is no.
In Patent Documents 10 and 11, there is no description of the strain hardening degree (λmax).

The polypropylene (X) according to the present invention preferably has a strain hardening degree (λmax) of 5 to 15. More preferably, the strain hardening degree (λmax) is 6 to 14.5, and further preferably 7 to 14. Among the polypropylenes (X) according to the present invention, those having a strain hardening degree (λmax) in this range are more preferable because the balance between spreadability and cell formation during foaming is particularly good.
Specific methods for controlling the strain hardening degree (λmax) within the above range include a method of changing the number of long-chain branches by adjusting the catalyst production method (particularly the loading ratio of the complex), and characteristics (X-iii). There is a method of adjusting the MFR within the range of When the number of long chain branches is increased or the MFR is lowered, the degree of strain hardening (λmax) increases. In order to lower the strain hardening degree (λmax), it may be adjusted in the opposite direction.

I-7. Other properties (X-vii): mm fraction The properties of the polypropylene (X) according to the present invention are as described above. Even more preferred.
Characteristic (X-vii): Isotactic triad fraction (mm fraction) determined by ¹³ C-NMR is 95% or more.

Here, the mm fraction indicates the abundance of two consecutive methyl groups in which the steric relationship between adjacent methyl groups is meso in the three chain of propylene units. The description in paragraphs [0053] to [0065] shall be followed. The measurement conditions for ¹³ C-NMR also follow JP 2009-275207 A.
The mm fraction is an index of stereoregularity, and a higher value means that propylene units are regularly arranged in the polymer chain, and the degree of crystallinity tends to increase. Accordingly, the higher the mm fraction, the higher the heat resistance and rigidity, so that it is preferable. In the present invention, the mm fraction is preferably 95% or more, more preferably 96% or more, and still more preferably 97% or more.
As a specific method for adjusting the mm fraction to the above range, a catalyst can be selected. The most important factor for determining the mm fraction of polypropylene having a long chain branch is a catalyst, and a catalyst satisfying the mm fraction may be selected from known catalysts. Specific examples of the catalyst will be described later.

II. Production method of polypropylene (X) The production method of polypropylene (X) in the present invention is not particularly limited as long as it satisfies the above-mentioned properties (X-i) to (X-iv). The preferred production method for satisfying all the conditions such as high stereoregularity, low low crystalline component amount, relatively wide molecular weight distribution, range of branching index g ′, high melt tension, etc. uses a combination of metallocene catalysts This method uses the macromer copolymerization method. As an example of such a method, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2009-57542 can be given.
This method produces a polypropylene having a long-chain branched structure using a catalyst in which a catalyst component having a specific structure having macromer-producing ability and a catalyst component having a specific structure having high molecular weight and macromer copolymerization ability are combined. According to this, industrially effective methods such as bulk polymerization and gas phase polymerization, particularly single-stage polymerization under practical pressure-temperature conditions, and using hydrogen as a molecular weight regulator. It is possible to produce a polypropylene having a long-chain branched structure having the desired physical properties.
In the past, it was necessary to increase the branching efficiency by lowering the crystallinity by using a polypropylene component having a low stereoregularity. However, in the above method, a polypropylene component having a sufficiently high stereoregularity is required. It can be introduced into the side chain by a simple method, and is preferred as the polypropylene resin (X) used in the present invention, which has high stereoregularity and low amount of low crystalline component (X-iv) and (X It is suitable for satisfying the characteristic of -v).
Moreover, if the said method is used, molecular weight distribution can be widened by using two types of catalysts from which a superposition | polymerization characteristic differs greatly, and it is required for the polypropylene (X) which has the long chain branched structure used for this invention (Xi). ) To (X-iii) can be satisfied at the same time, which is preferable.
Hereinafter, this method is selected as a specific example of the method for producing polypropylene (X) and will be described in detail.

II-1. Catalyst It is preferable to use a catalyst comprising the following catalyst components (A), (B) and (C).
Catalyst component (A): at least one component from component [A-1] which is a compound represented by the following general formula (a1), and component [A-2] which is a compound represented by the following general formula (a2) 2 or more transition metal compounds of Group 4 of the periodic table selected from at least one.
Component [A-1]: Compound represented by general formula (a1) Component [A-2]: Compound represented by general formula (a2) 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. Each of R ¹³ and R ¹⁴ independently represents an aryl group having 6 to 16 carbon atoms which may contain halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a plurality of heteroelements selected from these, Alternatively, it represents a heterocyclic group containing nitrogen, oxygen or sulfur having 6 to 16 carbon atoms. X ¹¹ and Y ¹¹ 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, oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, amino group, nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, alkylamide group having 1 to 20 carbon atoms, trifluoromethane A sulfonic acid group or a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms is represented. Q ¹¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, or 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, or a substituted 2-thienyl group. , A substituted 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 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. Among these, a methyl group and a trimethylsilyl group are preferable, and a methyl group is more 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.
As the aryl group having 6 to 16 carbon atoms which may contain halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a plurality of heteroelements selected from R ¹³ and R ¹⁴ , Within the range of 6 to 16, on the aryl cyclic skeleton, one or more hydrocarbon group having 1 to 6 carbon atoms, silicon-containing hydrocarbon group having 1 to 6 carbon atoms, halogen containing 1 to 6 carbon atoms You may have a hydrocarbon group etc. as a substituent.

R ¹³ and R ¹⁴ are preferably at least one of phenyl group, 4-methylphenyl group, 4-i-propylphenyl group, 4-t-butylphenyl group, 4-trimethylsilylphenyl group, 2,3- A dimethylphenyl group, a 3,5-di-t-butylphenyl group, a 4-phenyl-phenyl group, a chlorophenyl group, a naphthyl group, or a phenanthryl group, more preferably a phenyl group, a 4-i-propylphenyl group, 4 -T-butylphenyl group, 4-trimethylsilylphenyl group, 4-chlorophenyl group. Further, it is preferable that R ¹³ and R ¹⁴ are the same.

In the general formula (a1), X ¹¹ and Y ¹¹ are auxiliary ligands and react with the catalyst component (B) to generate an active metallocene having olefin polymerization ability. Therefore, as long as this object is achieved, X ¹¹ and Y ¹¹ are not limited in the type of ligand, and are independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms. A C1-C20 silicon-containing hydrocarbon group, a C1-C20 halogenated hydrocarbon group, a C1-C20 oxygen-containing hydrocarbon group, an amino group, or a C1-C20 nitrogen-containing hydrocarbon Group, an alkoxy group having 1 to 20 carbon atoms, an alkylamide group having 1 to 20 carbon atoms, a trifluoromethanesulfonic acid group, or a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms.

In the general formula (a1), Q ¹¹ is a binding group that bridges two conjugated five-membered rings, and is a divalent hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group having 1 to 20 carbon atoms. Either a silylene group or a germylene group which may be present is shown. When two hydrocarbon groups are present on the above-mentioned silylene group or germylene group, they may be bonded to each other to form a ring structure.
Specific examples of Q ¹¹ include alkylene groups such as methylene, methylmethylene, dimethylmethylene and 1,2-ethylene; arylalkylene groups such as diphenylmethylene; silylene groups; methylsilylene, dimethylsilylene, diethylsilylene, di ( n-propyl) silylene, di (i-propyl) silylene, alkylsilylene groups such as di (cyclohexyl) silylene, (alkyl) (aryl) silylene groups such as methyl (phenyl) silylene; arylsilylene groups such as diphenylsilylene; tetra An alkyl oligosilylene group such as methyldisilylene; a germylene group; an alkylgermylene group in which the silicon of the above-mentioned divalent hydrocarbon group having 1 to 20 carbon atoms is replaced with germanium; (alkyl) (aryl) germylene Group; arylgermylene group And so on. 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 more preferable.

Of the compounds represented by the general formula (a1), preferred compounds are specifically exemplified 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, dichloro [1,1′-dimethylsilylenebis {2- (2-benzofuryl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-methylphenyl) Nyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) -indenyl}] hafnium, dichloro [1 , 1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-trimethylsilylphenyl) -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, di Loro [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′-dimethyl Silylenebis {2- (2-furyl) -4- (2-phenanthryl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4- ( -Phenanthryl) -indenyl}] hafnium, 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-tert-butyl-2-furyl) -4- (1-naphthyl) -indenyl}] hafnium, Chloro [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-t-butyl-2-furyl) -4- (9-phenanthryl) -indenyl}] hafnium, and the like.

Of these, more preferred are dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylene. Bis {2- (5-methyl-2-furyl) -4- (4-methylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-trimethylsilylphenyl) -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- (2-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- ( 5-methyl-2-furyl) -4- (4-tert-butylphenyl) -indenyl}] hafnium.
More preferably, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2- (5-Methyl-2-furyl) -4- (4-i-propylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-Trimethylsilylphenyl) -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 independently represents a hydrocarbon group having 1 to 6 carbon atoms. R ²³ and R ²⁴ are each independently an aryl group having 6 to 16 carbon atoms which may contain halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a plurality of hetero elements selected from these. is there. 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. Represents a 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, or carbon It represents a silylene group or a germylene group, which may have a hydrocarbon group of 1 to 20. 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 may each independently contain halogen having 6 to 16 carbon atoms, preferably 6 to 12 carbon atoms, silicon, or a plurality of hetero elements selected from these. An 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.

X ²¹ and Y ²¹ are auxiliary ligands, and react with the catalyst component (B) to generate active metallocene having olefin polymerization ability. Therefore, as long as this object is achieved, X ²¹ and Y ²¹ are not limited to the type of ligand, and are independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms. A C1-C20 silicon-containing hydrocarbon group, a C1-C20 halogenated hydrocarbon group, a C1-C20 oxygen-containing hydrocarbon group, an amino group, or a C1-C20 nitrogen-containing hydrocarbon Group, an alkoxy group having 1 to 20 carbon atoms, an alkylamide group having 1 to 20 carbon atoms, a trifluoromethanesulfonic acid group, and a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms.

Q ²¹ is a binding group that bridges two conjugated five-membered rings, and may have a divalent hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group having 1 to 20 carbon atoms. A silylene group or a germylene group is shown. When two hydrocarbon groups are present on the silylene group or the germylene group, they may be bonded to each other to form a ring structure. A substituted silylene group or a substituted germylene group is preferred.

  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 the representative exemplary compounds are described below avoiding many complicated examples, and the present invention is not construed to be limited to these compounds, and various ligands, crosslinking groups, or auxiliary coordination It is obvious that children can be used arbitrarily.
Moreover, although the compound in which the central metal is hafnium has been described, a compound substituted for zirconium is similarly treated as disclosed in the present specification.

  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- ( -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)- -Hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (2-fluoro-4-biphenylyl) -4-hydroazurenyl}] 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}] huff Nitrogen, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (3-chloro-4-tert-butylphenyl) -4-hydroazulenyl}] 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-t-butylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′- (9-silafluorene-9,9-diyl) bis {2-ethyl-4- (4-chlorophenyl) -4-hydroazurenyl}] Funium, 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-hydroazulenyl}] 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-hydroazulenyl}] 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′-dimethyl. Silylenebis {2-ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4-hydroazuleni }] Hafnium, dichloro [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3,5-dichloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium .

  More preferably, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- Ethyl-4- (2-fluoro-4-biphenylyl) -4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4 -Hydroazulenyl}] hafnium, dichloro [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3,5-dichloro-4-trimethylsilylphenyl) -4-hydroazurenyl} ] Hafnium.

(2) Catalyst component (B)
The catalyst component (B) preferably used for producing the polypropylene resin (X) is an ion-exchange layered silicate.
(I) Types of ion-exchanged layered silicates Ion-exchanged layered silicates (hereinafter sometimes simply referred to as silicates) are surfaces in which ionic bonds and the like are stacked in parallel with each other with a binding force. This refers to a silicate compound having a crystal structure and containing exchangeable ions. 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 size, crystallinity, and dispersion state of these impurities, it may be preferable to pure silicate, and such a complex is also included in the catalyst component (B).
The silicate used in the present invention is not limited to a natural product, and may be an artificial synthetic product or may contain 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 smectite groups, vermiculite groups such as vermiculite, mica, illite, sericite, sea chlorite and other mica groups, attapulgite, sepiolite, palygorskite , Bentonite, pyrophyllite, talc, chlorite group, etc.
The silicate 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-exchange layered silicate can 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 for 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 addition, you may use what combined the following acids and salts as a processing agent. A combination of these acids and salts may also be used.

<Salt treatment>:
Ion-exchange 40% or more, preferably 60% or more of the exchangeable metal cations contained in the ion-exchange layered silicate before being treated with salts with cations dissociated from the salts shown below. Is preferred.
Salts used in such salt treatment for ion exchange are composed of at least one cation selected from the group consisting of an organic cation, an inorganic cation and a metal ion, and an organic anion and an inorganic anion. Examples thereof include salts composed of at least one anion selected from the group. For example, at least selected from the group consisting of a cation containing at least one atom selected from the group consisting of Group 1 to 14 atoms of the periodic table, a halogen anion, and an anion derived from an inorganic acid and an organic acid A preferred example is a compound composed of a kind of anion. Here, the anion derived from an acid is an anion in which at least one hydrogen cation is eliminated from the acid. For example, in the case of a monovalent inorganic acid such as HNO ₃ , the anion derived from the acid is NO ₃ ^— , and in the case of a trivalent inorganic acid such as H ₃ PO ₄ , the acid There are three types of anions derived from H ₂ PO ₄ ⁻ , HPO ₄ ²⁻ and PO ₄ ³⁻ . The same applies to anions derived from organic acids. More preferred is a compound in which the cation is a metal ion and the anion is an anion derived from an inorganic acid or a halogen anion.

Specific examples of such salts are LiF, LiCl, LiBr, LiI, Li ₂ SO ₄ , Li (CH ₃ COO), Li ₂ CO ₃ , LiHCO ₂ , Li ₂ C ₂ O ₄ , LiClO ₄ , Li _3. PO ₄ , CaCl ₂ , CaSO ₄ , CaC ₂ O ₄ , Ca (NO ₃ ) ₂ , MgCl ₂ , MgBr ₂ , MgSO ₄ , Mg ₃ (PO ₄ ) ₂ , Mg (ClO ₄ ) ₂ , MgC ₂ O ₄ , _{mg (NO 3) 2, mg} (CH 3 COO) 2 and the like.

_{Further, Ti (CH 3 COO) 4} , Ti (CO 3) 2, Ti (NO 3) 4, Ti (SO 4) 2, TiF 4, TiCl 4, Zr (CH 3 COO) 4, Zr (CO 3) ₂ , Zr (NO ₃ ) ₄ , Zr (SO ₄ ) ₂ , ZrF ₄ , ZrCl ₄ , Hf (CH ₃ COO) ₄ , Hf (CO ₃ ) ₂ , Hf (NO ₃ ) ₄ , Hf (SO ₄ ) _{2 , HfF 4, HfCl 4, V} (CH 3 COCHCOCH 3) 3, VOCl 3, VCl 3, VCl 4, VBr 3 , etc. may be mentioned.

Also, Cr (CH ₃ COCHCOCH ₃ ) ₃ , Cr (NO ₃ ) ₃ , Cr (ClO ₄ ) ₃ , CrPO ₄ , Cr ₂ (SO ₄ ) ₃ , CrF ₃ , CrCl ₃ , CrBr ₃ , CrI ₃ , Mn ( CH ₃ COO) ₂ , Mn (CH ₃ COCHCOCH ₃ ) ₂ , MnCO ₃ , Mn (NO ₃ ) ₂ , MnO, Mn (ClO ₄ ) ₂ , MnF ₂ , MnCl ₂ , Fe (CH ₃ COO) 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 and the} like.

In addition, Co (CH ₃ COO) 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 (CH ₃ COO) 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, and tetraphenylborate other than the anion 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. These adsorbed water and interlayer water are preferably removed and used 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 the removal is 3% by weight or less when the water content when dehydrating for 2 hours under the conditions of a temperature of 200 ° C. and a pressure of 1 mmHg is 0% by weight, It is preferably 1% by weight or less.

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

  The ion-exchange layered silicate can be treated with a catalyst component (C) of an organoaluminum compound, which will be described later, before formation of a catalyst or use as a catalyst, which is preferable. 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 prepolymerization or 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) is an organoaluminum compound. Organic aluminum compounds used as the catalyst component (C) has the general ^{_{formula: (AlR 31 q Z 3-}} q) a compound represented by _p is suitable. The compounds represented by this formula can be used alone, in combination of plural kinds or in combination. In this formula, R ³¹ 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 ³¹ 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 or alkylaluminum hydride having p = 1 and q = 3 is preferable. More preferably, R ³¹ is trialkylaluminum having 1 to 8 carbon atoms.

(4) Catalyst formation / preliminary polymerization In the catalyst, the catalyst components (A) to (C) are brought into contact with each other in the (preliminary) polymerization tank simultaneously or continuously, or once or multiple times. Can be formed.
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.
Before contacting the catalyst component (A) with the catalyst component (B), the catalyst component (A), the catalyst component (B), or both the catalyst component (A) and the catalyst component (B) C), or contacting the catalyst component (C) with the catalyst component (A) and the catalyst component (B), or contacting the catalyst component (A) and the catalyst component (B). Although it is possible to contact the catalyst component (C) after contacting, preferably, the catalyst component (C) is brought into contact with any one of the catalyst component (C) before contacting the catalyst component (A) and the catalyst component (B). Is the method.
Moreover, after contacting each component, it is possible to wash with an aliphatic hydrocarbon or an aromatic hydrocarbon solvent.

The usage-amount of catalyst component (A), (B) and (C) 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 1,000 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) with respect to the catalyst component (A) is preferably in the range of 0.01 to 5 × 10 ⁶ , particularly preferably 0.1 to 1 × 10 ⁴ in terms of the molar ratio of the transition metal. preferable.

The ratio of said component [A-1] (compound represented by general formula (a1)) and said component [A-2] (compound represented by general formula (a1)) used by this invention is a propylene type | system | group. Although it is arbitrary as long as the above properties of the polymer are satisfied, the molar ratio of the transition metal of [A-1] to the total amount of each component [A-1] and [A-2], preferably 0.30 or more 0.99 or less.
By changing this ratio, it is possible to adjust the balance between melt physical properties and catalyst activity. That is, from the component [A-1], a low molecular weight terminal vinyl macromer is produced, and from the component [A-2], a high molecular weight body 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 physical properties such as strain hardening degree, melt tension, and melt spreadability can be controlled.

In order to produce a higher strain-hardening propylene polymer, 0.30 or more is required,
Preferably it is 0.40 or more, More preferably, it is 0.5 or more. Further, the upper limit is 0.99 or less, and in order to efficiently obtain polypropylene resin (X) with high catalytic activity, it is preferably 0.95 or less, and more preferably 0.90 or less. .
In addition, by using component [A-1] within the above range, it is possible to adjust the balance between the average molecular weight and the catalytic activity with respect to the amount of hydrogen.

The catalyst according to the present invention is subjected to a prepolymerization treatment consisting of a small amount of polymerization by bringing the 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 physical 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 speed or in a constant pressure state, 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 catalyst component (B). Moreover, a catalyst 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.

II-2. Polymerization Method (1) Use of Catalyst / Propylene Polymerization As for the polymerization mode, if the olefin polymerization catalyst including the catalyst component (A), the catalyst component (B) and the catalyst component (C) and the monomer are in efficient contact, Any style can be adopted.
Specifically, a slurry polymerization method using an inert solvent, a so-called bulk polymerization method, a solution polymerization method using substantially no inert solvent as a solvent, or a gas without using a liquid solvent. For example, a gas phase polymerization method for maintaining the shape can be employed. Moreover, the method of performing continuous polymerization and batch type 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 the slurry polymerization method, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene, and toluene 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 a bulk polymerization method is used, it is preferably 40 ° C. or higher, more preferably 50 ° C. or higher. The upper limit is preferably 80 ° C. or lower, more preferably 75 ° C. or lower.
Furthermore, when using a gas phase polymerization method, it is preferably 40 ° C. or higher, more preferably 50 ° C. or higher. The upper limit is preferably 100 ° C. or lower, more preferably 90 ° C. or lower.
The polymerization pressure is preferably 1.0 MPa or more and 5.0 MPa or less. In particular, when a bulk polymerization method is used, 1.5 MPa or more is preferable, and 2.0 MPa or more is more preferable. The upper limit is preferably 4.0 MPa or less, more preferably 3.5 MPa or less.

Furthermore, when using vapor phase polymerization, 1.5 MPa or more is preferable, and 1.7 MPa or more is more preferable. Further, the upper limit is preferably 2.5 MPa or less, and more preferably 2.3 MPa or less.
Further, as a molecular weight regulator and for an activity improving effect, hydrogen is supplementarily used in a molar ratio of 1.0 × 10 ⁻⁶ or more and 1.0 × 10 ⁻² or less with respect to propylene. it can.

Also, by changing the amount of hydrogen used, in addition to the average molecular weight of the polymer to be produced, the molecular weight distribution, the deviation of the molecular weight distribution toward the high molecular weight side, very high molecular weight components, branching (amount, length, Distribution) can be controlled, whereby the melt properties characterizing polypropylene having a long chain branching structure such as MFR, strain hardening degree, melt tension MT, and melt spreadability can be controlled.
Therefore, hydrogen should be used in a molar ratio to propylene of 1.0 × 10 ⁻⁶ or more, preferably 1.0 × 10 ⁻⁵ or more, more preferably 1.0 × 10 ⁻⁴ or more. Is good. Moreover, regarding an upper limit, it is good to use at 1.0 * 10 ^<-2> or less, Preferably it is 0.9 * 10 ^<-2> or less, More preferably, it is 0.8 * 10 ^<-2> or less.

In addition to the propylene monomer, copolymerization using an α-olefin comonomer having 2 to 20 carbon atoms excluding propylene such as ethylene and / or 1-butene as a comonomer may be performed depending on the use.
Therefore, in order to obtain polypropylene (X) used in the present invention having a good balance between catalytic activity and melt properties, it is necessary to use ethylene and / or 1-butene at 15 mol% or less based on propylene. More preferably, it is 10.0 mol% or less, More preferably, it is 7.0 mol% or less.

  When propylene is polymerized using the catalyst and polymerization method exemplified here, one end of the polymer is mainly propenyl from the active species derived from the catalyst component [A-1] by a special chain transfer reaction generally called β-methyl elimination. The structure is shown and so-called macromers are produced. This macromer can generate a higher molecular weight and is taken into the active species derived from the catalyst component [A-2] having a better copolymerization property, and it is considered that the macromer copolymerization proceeds. Therefore, it can be considered that a comb-shaped chain is mainly used as a branched structure of a polypropylene resin having a long-chain branched structure.

III. Number of gels When the polypropylene resin composition for foam molding according to the present invention is an unstretched film having a thickness of 25 μm, the number of gels having a major axis of 0.5 mm or more is 50 / m ² or less. Preferably, when an unstretched film having a thickness of 25 μm is used, the number of gels having a major axis of 0.5 mm or more is 50 / m ² or less, and the number of gels having a major axis of 0.4 mm or more and less than 0.5 mm is 400 / m 2. ² or less. More preferably, when an unstretched film having a thickness of 25 μm is used, the number of gels having a major axis of 0.5 mm or more is 50 / m ² or less, and the number of gels having a major axis of 0.4 mm or more and less than 0.5 mm is 400 / m ^2. m ² or less, the number of gels less than the major diameter 0.3 mm 0.4 mm is 2000 / ^{m 2} or less.

When the polypropylene resin for foam molding according to the present invention is an unstretched film having a thickness of 25 μm, the number of gels having a major axis of 0.5 mm or more is 10 / m ² or less. Preferably, in the case of an unstretched film having a thickness of 25 μm, the number of gels having a major axis of 0.5 mm or more is 10 / m ² or less, and the number of gels having a major axis of 0.2 mm or more and less than 0.5 mm is 50 / m 2. ² or less. More preferably, when the non-stretched film has a thickness of 25 μm, the number of gels having a major axis of 0.5 mm or more is 10 / m ² or less, and the number of gels having a major axis of 0.2 mm or more and less than 0.5 mm is 50 / m ² or less, the number of gels less than the major diameter 0.1 mm 0.2 mm is 100 / ^{m 2} or less.

  The unstretched film can be produced with a conventional film molding apparatus using a polypropylene resin for foam molding, a polypropylene resin composition for foam molding, and other samples. For example, the sample can be prepared by putting it into a conventional extruder equipped with a T-die, performing extrusion under appropriate conditions, and taking it out with a conventional film take-up machine. The number of gels of the produced unstretched film can be counted by a conventional defect detector. It is convenient to count the number of gels at the center of the film between the take-up machine and the winder. It is recommended that the inspection width, the inspection length, and the number of inspections are appropriately set, and the average value obtained for each size category is calculated by converting the unit area. Details will be described in the following examples.

IV. Polypropylene resin for foam molding made of polypropylene (X) As described above, the polypropylene resin for foam molding of the present invention has a melt tension (230 ° C.) of 3 g or more, and has a predetermined range when it is an unstretched film having a thickness of 25 μm. The long diameter gel is made of polypropylene (X) having a predetermined number or less per unit area. And preferably, polypropylene (X) satisfy | fills said characteristic (Xi)-(X-iv). Additives, foaming agents, extrusion foaming, foamed sheets, multilayer foamed sheets, thermoformability, molded products, uses, etc. will be described together in the following description of the polypropylene resin composition for foam molding.

V. Propylene block copolymer (Y)
Although it does not specifically limit as a component (Y) mix | blended with polypropylene (X) which has the above-mentioned long chain branched structure, Propylene (co) polymer (Y-1) and propylene-ethylene copolymer (Y-2) It is preferable to use a propylene-based block copolymer (Y) consisting of More preferably, it is produced by performing multistage polymerization by a conventionally known sequential polymerization method.
The term block copolymer used here is different from a so-called (real) block copolymer or graft copolymer in which components polymerized at each stage are bonded by chemical bonding. Since the components produced in each step of multi-stage polymerization are not chemically bonded, in general, the difference in crystallinity, molecular weight, solubility in solvent, etc. is used for each component, so that fractionation of crystallinity is achieved. It is possible to separate each component produced in each step by a method such as molecular weight fractionation or solubility fractionation.
In addition, in the block copolymer (Y) obtained by a conventionally known sequential polymerization method, the existence of a long chain branched structure by a chemical bond such as the polypropylene (X) is not recognized with an analyzable accuracy.

1. Propylene Block Copolymer (Y) Production Method, Polymerization Catalyst Any catalyst can be used to produce the propylene block copolymer (Y), but the following properties (Yi) When producing propylene-ethylene copolymer (Y-2) satisfying (Yv) as a constituent component, it is preferable to use a Ziegler-Natta catalyst. In the case of using a Ziegler-Natta catalyst, a specific method for producing the catalyst is not particularly limited, but as an example, a catalyst disclosed in JP 2007-254671 A can be exemplified.
Specifically, as representative examples of the Ziegler-Natta catalyst suitable for the production of the propylene-based block copolymer (Y) of the present invention, the following constituents:
(ZN-1) a solid component containing titanium, magnesium, and halogen as essential components,
(ZN-2) an organoaluminum compound,
(ZN-3) an electron donor,
The catalyst which consists of can be mentioned.

(1) Solid component (ZN-1)
The solid component (ZN-1), which is a constituent of the Ziegler-Natta catalyst suitable for the production of the propylene-based block copolymer (Y) of the present invention, is titanium (ZN-1a), magnesium (ZN-1b), halogen (ZN-1c) is contained as an essential component, and an electron donor (ZN-1d) can be used as an optional component. Here, “containing as an essential component” indicates that any component may be included in any form within the range not impairing the effects of the present invention, in addition to the listed three components. . This will be described in detail below.

(ZN-1a) Titanium Any arbitrary titanium compound can be used as a titanium source. Typical examples include compounds disclosed in JP-A-3-234707. With respect to the valence of titanium, a titanium compound having any valence of tetravalent, trivalent, divalent, and zero can be used, but it is desirable to use a tetravalent titanium compound.

(ZN-1b) Magnesium Any magnesium compound can be used as the magnesium source. Representative examples include compounds disclosed in JP-A-234707. In general, magnesium chloride, diethoxymagnesium, metallic magnesium, and butylmagnesium chloride are often used.

(ZN-1c) Halogen As the halogen, fluorine, chlorine, bromine, iodine, and a mixture thereof can be used. Of these, chlorine is particularly preferred.

(ZN-1d) Electron Donor The solid component (ZN-1) may contain an electron donor as an optional component. Representative examples of the electron donor (ZN-1d) include compounds disclosed in JP-A No. 2004-124090. In general, organic acids and inorganic acids, and derivatives thereof (esters, acid anhydrides, acid halides, amides), ether compounds, ketone compounds, aldehyde compounds, alcohol compounds, amine compounds, It is desirable to use etc.
Among these, preferred are dibutyl phthalate, dibutyl phthalate, diisobutyl phthalate, phthalic acid ester compounds typified by diheptyl phthalate, phthalic acid halide compounds typified by phthaloyl dichloride, 2-n- Malonic acid ester compounds having one or two substituents at the 2-position such as butyl-diethyl malonate, one or two substituents at the 2-position such as 2-n-butyl-diethyl succinate, or 2 Succinic acid ester compounds having one or more substituents at each of the 3-position and 2-isopropyl-2-isobutyl-1,3-dimethoxypropane or 2-isopropyl-2-isopentyl-1,3-dimethoxypropane Aliphatic polyhydric ether compounds represented by 1,3-dimethoxypropane having one or two substituents at the 2-position , Polyvalent ether compounds having 9,9-bis radical of aromatic typified by (methoxymethyl) fluorene in the molecule, and the like.

(2) Organoaluminum compound (ZN-2)
As the organoaluminum compound (ZN-2), compounds disclosed in JP-A No. 2004-124090 can be used. In general, it is desirable to use a compound represented by the following general formula (5).
R ⁹ cAlXd (OR ¹⁰ ) e (5)
(In the general formula (5), R ⁹ represents a hydrocarbon group. X represents a halogen or a hydrogen atom. R ¹⁰ represents a hydrocarbon group or a bridging group by Al. C ≧ 1, 0 ≦ d. ≦ 2, 0 ≦ e ≦ 2, c + d + e = 3)

  Specific examples include trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum chloride, diethylaluminum ethoxide, methylalumoxane, and the like.

(3) Electron donor (ZN-3)
Examples of the electron donor (ZN-3) include an organosilicon compound (ZN-3a) having an alkoxy group or a compound (ZN-3b) having at least two ether bonds.

(ZN-3a) Organosilicon compound having alkoxy group Organosilicon compound having an alkoxy group (ZN-3a) which is a constituent component of a Ziegler-Natta catalyst suitable for the production of the propylene-based block copolymer (Y) according to the present invention ) May be the compounds disclosed in JP-A No. 2004-124090. In general, it is desirable to use a compound represented by the following general formula (3).
R ³ R ⁴ aSi (OR ⁵ ) b (3)
(In General Formula (3), R ³ represents a hydrocarbon group or a heteroatom-containing hydrocarbon group. R ⁴ is selected from the group consisting of a hydrogen atom, a halogen atom, a hydrocarbon group, and a heteroatom-containing hydrocarbon group. R ⁵ represents a hydrocarbon group, 0 ≦ a ≦ 2, 1 ≦ b ≦ 3, a + b = 3.

Specific examples include t-Bu (Me) Si (OMe) ₂ , t-Bu (Me) Si (OEt) ₂ , t-Bu (Et) Si (OMe) ₂ , t-Bu (n-Pr). _{Si (OMe) 2, c-} Hex (Me) Si (OMe) 2, c-Hex (Et) Si (OMe) 2, c-Pen 2 Si (OMe) 2, i-Pr 2 Si (OMe) 2, _{i-Bu 2 Si (OMe)} 2, i-Pr (i-Bu) Si (OMe) 2, n-Pr (Me) Si (OMe) 2, t-BuSi (OEt) 3, (Et 2 n) 2 _{Si (OMe) 2, Et 2} N-Si (OEt) 3, and the like.

(ZN-3b) Compound having at least two ether bonds As the compound having at least two ether bonds (ZN-3b), compounds disclosed in JP-A-3-294302 and JP-A-8-333413, etc. Can be used. In general, it is desirable to use a compound represented by the following general formula (4).
_{^{R 8 O-C (R 7}} ) 2 -C (R 6) 2 -C (R 7) 2 -OR 8 ... (4)
(In General Formula (4), R ⁶ and R ⁷ represent any free radical selected from the group consisting of a hydrogen atom, a hydrocarbon group, and a heteroatom-containing hydrocarbon group. R ⁸ represents a hydrocarbon group or a hetero group. Represents an atom-containing hydrocarbon group.)

  As specific examples, 2,2-diisopropyl-1,3-dimethoxypropane, 2,2-diisobutyl-1,3-dimethoxypropane, 2-isobutyl-2-isopropyl-1,3-dimethoxypropane, 2-isopropyl -2-isopentyl-1,3-dimethoxypropane, 2,2-dicyclopentyl-1,3-dimethoxypropane, 9,9-bis (methoxymethyl) fluorene, and the like.

(4) Prepolymerization The catalyst exemplified above may be prepolymerized before being used in the main polymerization. Prior to the polymerization process, a small amount of polymer is generated around the catalyst in advance, so that the catalyst becomes more uniform and the generation amount of fine powder can be suppressed.
As the monomer in the prepolymerization, compounds disclosed in JP-A No. 2004-124090 can be used. Specifically, ethylene, propylene, 3-methylbutene-1, 4-methylpentene-1, styrene, divinylbenzenes, and the like are particularly preferable.
The reaction conditions for the catalyst exemplified above and the above monomer are not particularly limited, but generally are preferably within the following ranges.
The prepolymerization amount is in the range of 0.001 to 100 g, preferably 0.1 to 50 g, more preferably 0.5 to 10 g, based on 1 g of the solid component (ZN-1). The reaction temperature during prepolymerization is -150 to 150 ° C, preferably 0 to 100 ° C. The reaction temperature during the prepolymerization is preferably lower than the polymerization temperature during the main polymerization. In general, the reaction is preferably carried out with stirring, and an inert solvent such as hexane or heptane can also be present.

(5) Sequential polymerization Next, the manufacturing method of the propylene-type block copolymer (Y) of this invention is explained in full detail.
The propylene-based block copolymer (Y) of the present invention is preferably a propylene-ethylene copolymer comprising a propylene (co) polymer (Y-1) and a propylene-ethylene copolymer (Y-2). In the production of such a propylene-based block copolymer (Y), two polymer components of a propylene (co) polymer (Y-1) and a propylene-ethylene copolymer (Y-2) are produced. There is a need. Propylene-based block copolymer (Y) inherently produced by neatly dispersing propylene-ethylene copolymer (Y-2) having relatively high molecular weight and low viscosity and MFR in propylene (co) polymer (Y-1) From the viewpoint of exhibiting the above performance, it is necessary to produce both the components by sequential polymerization.

Specifically, it is desirable to polymerize the propylene-ethylene copolymer (Y-2) in the second step after polymerizing the propylene (co) polymer (Y-1) in the first step. Although it is possible to reverse the order of production, the propylene-ethylene copolymer (Y-2) has an ethylene content of 11.0% by weight or more and 60% according to the definition of (Y-iv). Because it is a polymer with a crystallinity of less than 0.0% by weight and low crystallinity, if it is produced in the first step, it may cause production troubles such as adhering inside the polymerization tank or clogging the transfer pipe. High and less preferred.
When performing sequential polymerization, either a batch method or a continuous method can be used, but it is generally desirable to use a continuous method from the viewpoint of productivity.
In the case of the batch method, propylene (co) polymer (Y-1) and propylene-ethylene copolymer (Y-2) are individually separated using a single polymerization reactor by changing the polymerization conditions with time. Can be polymerized. As long as the effects of the present invention are not impaired, a plurality of polymerization reactors may be connected in parallel.
In the case of a continuous process, since it is necessary to polymerize propylene (co) polymer (Y-1) and propylene-ethylene copolymer (Y-2) separately, two or more polymerization reactors are connected in series. It is necessary to use equipment. For the polymerization reactor corresponding to the first step for producing the propylene (co) polymer (Y-1) and the polymerization reactor corresponding to the second step for producing the propylene-ethylene copolymer (Y-2), Although it must be in a serial relationship, a plurality of polymerization reactors may be connected in series and / or in parallel for each of the first step and the second step.

(6) Polymerization process Any polymerization process can be used.
The reaction phase may be a method using a liquid medium or a method using a gas medium. Specific examples include a slurry method, a bulk method, and a gas phase method. Although it is possible to use supercritical conditions as intermediate conditions between the bulk method and the gas phase method, they are substantially equivalent to the gas phase method, and are therefore included in the gas phase method without particular distinction. In the case of a multi-tank continuous polymerization process, a bulk polymerization reactor may be followed by a gas phase polymerization reactor. In this case, it will be referred to as a bulk method in accordance with the practice of the industry. In the case of the batch method, the first step may be performed by a bulk method, and the second step may be performed by a vapor phase method. This case is also referred to as a bulk method. As described above, the reaction phase is not particularly limited, but the slurry method has a problem that production costs are generally increased because of the use of an organic solvent such as hexane and heptane because there are many attached facilities. Therefore, it is more desirable to use a bulk method or a gas phase method.
Various processes have been proposed for the bulk method and the gas phase method. Although there is a difference in the stirring (mixing) method and the heat removal method, the present invention does not limit the particular process type in this respect.

(7) General polymerization conditions The polymerization temperature can be used without any particular problem as long as it is within a commonly used temperature range. Specifically, a range of 0 ° C to 200 ° C, preferably 40 ° C to 100 ° C can be used.
Although the polymerization pressure varies depending on the process to be selected, it can be used without any problem as long as it is in a pressure range usually used. Specifically, a range of greater than 0 to 200 MPa, preferably 0.1 to 50 MPa can be used. At this time, there is no problem even if an inert gas such as nitrogen coexists.
In the second step of producing the propylene-ethylene copolymer (Y-2), a polymerization inhibitor such as ethanol or oxygen can be added. When such a polymerization inhibitor is used, not only the polymerization amount in the second step can be easily controlled, but also the properties of the polymer particles can be improved.

(Y-1) produced in the previous stage of sequential polymerization is a propylene homopolymer or a propylene random copolymer obtained by copolymerizing a small amount of a comonomer without departing from the gist of the present invention. As the comonomer, an α-olefin having up to about 10 carbon atoms excluding 3 such as ethylene, butene and hexene is usually used.
Although there is no restriction | limiting in particular in the content of the said comonomer, It is preferable that it is 10 wt% or less, More preferably, it is 3 wt% or less, Most preferably, it is 1 wt% or less. The comonomer content is usually controlled by appropriately adjusting the amount ratio of the monomer supplied to the polymerization tank (eg, the amount ratio of ethylene to propylene). The copolymerization characteristics of the catalyst to be used may be examined in advance, and the monomer feed ratio may be adjusted so that the gas composition in the polymerization tank has a value corresponding to the desired comonomer content.

2. Properties of Propylene Block Copolymer (Y) As a result of many experimental studies, the present inventors have found that the propylene block copolymer (Y) blended with the polypropylene resin (X) has the following (Y-i It was found that the polypropylene (X) having the long-chain branched structure can suppress the formation of a structure formed under shear flow when having the characteristics of () to (Yv). This will be described in detail below.

2-1. Characteristic (Yi): Quantity ratio of (Y-1) and (Y-2) The weight ratio of (Y-1) and (Y-2) recommended in the present invention is 50 for (Y-1). It is -99 wt%, Preferably it is 55-97 wt%, More preferably, it is 60-95 wt%. Correspondingly, (Y-2) is 1 to 50 wt%, preferably 3 to 45 wt%, more preferably 5 to 40 wt%.
(However, regarding the weight ratio of (Y-1) and (Y-2), the total amount of the propylene-based block copolymer (Y) is 100 wt%)

When this propylene-based block copolymer (Y) is blended with polypropylene (X) having a long-chain branched structure, good extensibility is imparted, and compared with the case where component (X) is used alone, Advantages such as a wide temperature range that can be molded by this molding method, good appearance, and good mechanical properties such as impact properties are obtained. When the amount of the (Y-2) component is set to be equal to or higher than the lower limit of the above range, these advantages are easily obtained. On the other hand, the amount of the crystalline component (Y-1) is set to be lower than the upper limit of the above range. Can be kept high, and the heat resistance and rigidity of the composition can be kept good.
The weight ratio of the propylene (co) polymer (Y-1) and the propylene-ethylene copolymer (Y-2) is the production amount and propylene in the first step for producing the propylene (co) polymer (Y-1). -It controls by the manufacturing amount in the 2nd process which manufactures an ethylene copolymer (Y-2). For example, in order to increase the amount of propylene (co) polymer (Y-1) and reduce the amount of propylene-ethylene copolymer (Y-2), the second step while maintaining the production amount of the first step It is only necessary to decrease the production time of the second step, and to shorten the residence time in the second step or to lower the polymerization temperature. In addition, it can be controlled by adding a polymerization inhibitor such as ethanol or oxygen or increasing the amount of addition when it is originally added. The reverse is also true.

2-2. Characteristic (Y-ii): MFR
The recommended MFR range of the propylene-based block copolymer (Y) used in the present invention is in the range of 0.1 to 200 g / 10 minutes, preferably 0.2 to 190 g / 10 minutes, more preferably The range is 0.5 to 180 g / 10 minutes, particularly preferably 2.1 to 170 g / 10 minutes.
This is a normal range as the MFR range of the resin used for various moldings. By setting the range above the lower limit of this range, the load of the extruder can be properly maintained and the flow of the resin can be kept stable. In addition, by setting the upper limit or less, the neck-in at the time of extrusion molding can be reduced, and sheet take-up can be facilitated.
In addition, the measuring method of MFR is the same as the measuring method in the above-mentioned polypropylene (X).
Next, a method for controlling the MFR of the propylene-based block copolymer (Y) will be described. For the MFR (Y) of the propylene-based block copolymer (Y), the MFR (Y-1) of the propylene (co) polymer (Y-1) and the MFR of the propylene-ethylene copolymer (Y-2) ( Y-2) holds the following relational expression.
log [MFR (Y)] = W (Y−1) × log [MFR (Y−1)] + W (Y−2) × log [MFR (Y−2)]
(Where log is a logarithm with e as the base. W (Y-1) and W (Y-2) are propylene (co) polymers in the propylene-based block copolymer (Y), respectively. (Y-1) is a weight ratio of propylene-ethylene copolymer (Y-2), and a relationship of W (Y-1) + W (Y-2) = 1 is established.

This relational expression is an empirical expression called a logarithmic addition law of viscosity, and is used routinely in the industry. That is, the weight ratio of propylene (co) polymer (Y-1) to propylene-ethylene copolymer (Y-2), MFR (Y), MFR (Y-1), and MFR (Y-2) are independent. is not. Therefore, in order to control MFR (Y), it is only necessary to control the three factors of weight ratio of propylene-ethylene copolymer (Y-2), MFR (Y-1), and MFR (Y-2). For example, in order to increase MFR (Y), MFR (Y-1) may be increased or MFR (Y-2) may be increased. Further, when MFR (Y-2) is lower than MFR (Y-1), even if W (Y-1) is increased and W (Y-2) is decreased, MFR (Y) is increased. You can easily understand that you can. The reverse control method is the same.
Which of these methods is more preferable will be described. It is necessary to control MFR (Y-2) to a somewhat low value from the definition of (Yv) described later. When controlling MFR (Y), It is desirable to use a method for controlling the weight ratio of MFR (Y-1) and / or (Y-1) and (Y-2). Furthermore, since the weight ratio of (Y-1) to (Y-2) is limited by the above (Yi), it is most preferable to use a method of controlling MFR (Y-1).
As a method for controlling MFR (Y-1) and MFR (Y-2), a method using hydrogen as a chain transfer agent is the simplest. Specifically, when the concentration of hydrogen as a chain transfer agent is increased, the MFR (Y-1) of the propylene (co) polymer (Y-1) is increased. The reverse is also true. In order to increase the concentration of hydrogen in the polymerization tank, it is only necessary to increase the amount of hydrogen supplied to the polymerization tank. The same applies to the control of MFR (Y-2).

2-3. Characteristic (Y-iii): Melting point The melting point of the propylene-based block copolymer (Y) used in the present invention is preferably higher than 155 ° C from the viewpoint of maintaining the heat resistance of the sheet, and is 157 ° C or higher. Is more preferable. The upper limit of the melting point is not particularly limited, but it is practically difficult to produce a melting point exceeding 170 ° C.
The melting point was determined by using differential operation calorimetry (DSC), once the temperature was raised to 200 ° C. and the thermal history was erased, then the temperature was lowered to 40 ° C. at a temperature lowering rate of 10 ° C./min, and the temperature rising rate was again It is set as the temperature of the endothermic peak top when measured at 10 ° C./min.
Since the melting point of the propylene-based block copolymer (Y) is mainly determined by the melting point of the propylene (co) polymer (Y-1), when controlling the melting point of the propylene-based block copolymer (Y), It is preferable to control the melting point of the propylene (co) polymer (Y-1). The melting point of the propylene-based block copolymer (Y) is determined by the MFR (Y-1) and comonomer content of the propylene (co) polymer (Y-1). When MFR (Y-1) is increased, the melting point of (Y-1) is decreased, and even when the comonomer content is increased, the melting point of (Y-1) is decreased. It is easy for those skilled in the art to investigate the relationship between the MFR (Y-1) or comonomer content and the melting point in advance and adjust the MFR (Y-1) or comonomer content so as to obtain the desired melting point. .

2-4. Characteristics (Y-iv): Ethylene content in propylene-ethylene copolymer component (Y-2) In the present invention, the ethylene content in propylene-ethylene copolymer component (Y-2) is 11 to 38 wt%. It is preferable that the total amount of monomers constituting the component (Y-2) be 100 wt%. A more preferable range of the ethylene content in the propylene-ethylene copolymer component (Y-2) is 16 to 36 wt%, and more preferably 18 to 35 wt%.
The ethylene content in the propylene-ethylene copolymer component (Y-2) is usually controlled by appropriately adjusting the amount ratio of ethylene supplied to the polymerization tank to propylene. The copolymerization characteristics of the catalyst to be used may be examined in advance, and the monomer supply ratio may be adjusted so that the gas composition in the polymerization tank has a value corresponding to the desired ethylene content.
If the ethylene content is within the above range, the effect of suppressing the formation of the structure formed by the polypropylene (X) having a long-chain branched structure under shear flow appears. Become. About the reason, the present inventors are estimating as follows.
The propylene-based block copolymer (Y) according to the present invention has a function of inhibiting the polypropylene (X) having a long-chain branched structure from forming a unique structure under shear. Since the structure is a so-called shishi kebab structure (or a precursor thereof), a component having as low crystallinity as possible and a low mobility, that is, a molecular weight as high as possible in order to suppress the growth of the structure. Ingredients are considered preferred. However, if the ethylene content falls below this specified range, (Y-2) itself has crystallinity, and the formation of a shishi-kebab structure cannot be suppressed. On the other hand, when the ethylene content of (Y-2) is too high, the (Y-2) component forms a sea-island structure with the (Y-1) component and exists as a completely different phase. Therefore, it cannot act on the formation of the shishi-kebab structure. That is, the ethylene content in (Y-2) needs to be in a range that does not have much crystallinity while maintaining compatibility with the crystalline propylene component to some extent.

2-5. Characteristic (Yv): Intrinsic viscosity of propylene-ethylene copolymer component (Y-2) Propylene-ethylene copolymer component constituting propylene-based block copolymer (Y) blended with polypropylene (X) ( The intrinsic viscosity value of Y-2) measured using 135 ° C. decalin as a solvent is preferably 5.3 dl / g or more, more preferably 6.0 dl / g or more, and still more preferably 7.0 dl / g or more. Most preferably, it is 7.5 dl / g or more.

The propylene-based block copolymer (Y) according to the present invention has a function of inhibiting the polypropylene (X) having a long-chain branched structure from forming a unique structure in a shear field. The structure is a so-called shishi kebab structure (or a precursor thereof), and therefore, a component having as low a crystallinity as possible and a component having as low a mobility as possible to suppress the growth of the structure, that is, a component having a high molecular weight. Is considered preferable. By setting the intrinsic viscosity value to be equal to or higher than the lower limit of this range, the effect of suppressing the formation of shishi-kebab structure can be increased.
The upper limit need not be specified, but if it is set below the upper limit, gel generation can be suppressed, so that it is 15.0 dl / g or less, preferably 14.0 dl / g or less, more preferably 13.0 dl / g or less. Most preferably, it is 12.0 dl / g or less.
Here, the intrinsic viscosity is a value measured using an Ubbelohde capillary viscometer using a temperature of 135 ° C., decalin as a solvent. In order to determine the intrinsic viscosity of (Y-2), using the same method as described in the above CXS, the component (Y-2) is recovered as a 25 ° C. paraxylene-soluble component, and the intrinsic viscosity is measured. Assumed to be performed. However, when the ethylene content of the (Y-2) component is less than 15% by weight, it is difficult to sufficiently separate the (Y-2) component depending on the CXS method. In such a case, a small amount of the component (Y-1) in the course of sequential polymerization is withdrawn, the intrinsic viscosity is measured, and further, the intrinsic viscosity of the whole (Y) after the completion of sequential polymerization is measured. Suppose you want.
Intrinsic viscosity of component (Y-2) = [(Y) Intrinsic viscosity of entire component− {Intrinsic viscosity of component (Y−1)
× (Y-1) component weight fraction / 100}] / {(Y-2) component weight fraction / 100}

  The intrinsic viscosity [η] is an amount corresponding to the molecular weight, and the method of using hydrogen as a chain transfer agent is the simplest method for controlling the intrinsic viscosity [η] as in MFR. Specifically, when the concentration of hydrogen as a chain transfer agent is increased, the intrinsic viscosity [η] of the propylene-ethylene copolymer (Y-2) is decreased. The reverse is also true. In order to increase the concentration of hydrogen in the polymerization tank, it is sufficient to increase the amount of hydrogen supplied to the polymerization tank, and adjustment is very easy for those skilled in the art.

Here, as a method for determining the ratio of (Y-1) and (Y-2) in component (Y) and the ethylene content in (Y-2), conventionally known IR and NMR, or solubility fractionation It can be determined by an analysis method combining the method and the IR method.
In the present invention, various indices of the component (Y) are mainly determined by a combination of the cross fractionation method and the FT-IR method described below.

(1) Analytical device to be used (i) Cross fractionation device CFC T-100 (abbreviated as CFC) manufactured by Dia Instruments Co., Ltd.
(Ii) Fourier transform infrared absorption spectrum analysis FT-IR, Perkin Elmer 1760X
The fixed wavelength infrared spectrophotometer attached as a CFC detector is removed, and an FT-IR is connected instead, and this FT-IR is used as a detector. The transfer line from the outlet of the solution eluted from the CFC to the FT-IR is 1 m long, and the temperature is maintained at 140 ° C. throughout the measurement. The flow cell attached to the FT-IR has an optical path length of 1 mm and an optical path width of 5 mm, and the temperature is maintained at 140 ° C. throughout the measurement.
(Iii) Gel permeation chromatography (GPC)
The GPC column at the latter stage of the CFC is used by connecting three AD806MS manufactured by Showa Denko in series.

(2) CFC measurement conditions (i) Solvent: orthodichlorobenzene (ODCB)
(Ii) Sample concentration: 4 mg / mL
(Iii) Injection volume: 0.4 mL
(Iv) Crystallization: The temperature is lowered from 140 ° C. to 40 ° C. over about 40 minutes.
(V) Sorting method:
The fractionation temperature at the time of temperature-raising elution fractionation is 40, 100, and 140 ° C., and fractionation is performed in three fractions in total. The elution ratio (unit weight%) of the component eluting at 40 ° C. or lower (fraction 1), the component eluting at 40 to 100 ° C. (fraction 2), and the component eluting at 100 to 140 ° C. (fraction 3) is W40. , W100 and W140. W40 + W100 + W140 = 100. Moreover, each fractionated fraction is automatically transported to the FT-IR analyzer as it is.
(Vi) Solvent flow rate during elution: 1 mL / min

(3) Measurement conditions of FT-IR After elution of the sample solution from GPC at the latter stage of the CFC starts, FT-IR measurement is performed under the following conditions, and GPC-IR data is collected for each of the above-described fractions 1 to 3. .
A conceptual diagram of CFC-FT-IR is shown in FIG.
(I) Detector: MCT
(Ii) Resolution: 8 cm ⁻¹
(Iii) Measurement interval: 0.2 minutes (12 seconds)
(Iv) Number of integrations per measurement: 15 times

(4) Post-treatment and analysis of measurement results The elution amount and molecular weight distribution of the components eluted at each temperature are obtained using the absorbance at 2945 cm ⁻¹ obtained by FT-IR as a chromatogram. The elution amount is normalized so that the total elution amount of each elution component is 100%. Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene. The specific method is the same as described above.
The ethylene content distribution (distribution of ethylene content along the molecular weight axis) of each eluted component is the ratio of the absorbance of 2956 cm ⁻¹ and the absorbance of 2927 cm ⁻¹ obtained by GPC-IR, and is obtained by using polyethylene, polypropylene, or ¹³ Using ethylene-propylene-rubber (EPR) whose ethylene content is known by C-NMR measurement or the like and a mixture thereof, the ethylene content (% by weight) is determined by a calibration curve prepared in advance. Calculate by conversion.

(5) Propylene-ethylene copolymer content The recommended propylene-ethylene copolymer (Y-2) (hereinafter referred to as EP) content of the propylene-based block copolymer (Y) in the present invention is as follows. It is defined by the formula (I) and is obtained by the following procedure.
EP content (% by weight) = W40 × A40 / B40 + W100 × A100 / B100 + W140 × A140 / B140 (I)
W40, W100, and W140 are the elution ratios (unit weight%) in each of the above-described fractions. B40, B100, and B140 are the ethylene content (unit weight%) of EP contained in each fraction.
A method for obtaining A40, A100, A140, B40, B100, and B140 will be described later.
The meaning of the formula (I) is as follows. The first term on the right side of the formula (I) is a term for calculating the amount of EP contained in fraction 1 (portion soluble at 40 ° C.). When fraction 1 contains only EP and does not contain PP, W40 contributes to the EP content derived from fraction 1 in the whole as it is, but fraction 1 contains a small amount in addition to EP-derived components. Since components derived from PP (extremely low molecular weight components and atactic polypropylene) are also included, it is necessary to correct the portion. Therefore, by multiplying W40 by A40 / B40, the amount derived from the EP component in fraction 1 is calculated. For example, when the average ethylene content (A40) of fraction 1 is 30% by weight and the ethylene content (B40) of EP contained in fraction 1 is 40% by weight, 30/40 = 3/4 of fraction 1 (Ie 75% by weight) comes from EP and the remaining 1/4 comes from PP. Thus, the operation of multiplying A40 / B40 in the first term on the right side means that the contribution of EP is calculated from the weight% (W40) of fraction 1. The same applies to the second term on the right side, and for each fraction, the EP content is calculated by adding and calculating the EP contribution.

(I) As described above, the average ethylene contents corresponding to the fractions 1 to 3 obtained by CFC measurement are A40, A100, and A140, respectively (the unit is% by weight). A method for obtaining the average ethylene content will be described later.
(Ii) The ethylene content corresponding to the peak position in the differential molecular weight distribution curve of fraction 1 is defined as B40 (unit is% by weight). For fractions 2 and 3, it is considered that the rubber part is completely eluted at 40 ° C. and cannot be defined with the same definition, so in the present invention, it is defined as B100 = B140 = 100. B40, B100, and B140 are the ethylene content of EP contained in each fraction, but it is practically impossible to obtain this value analytically. The reason is that there is no means for completely separating and separating PP and EP mixed in the fraction. As a result of examination using various model samples, it was found that B40 can explain the effect of improving the material properties well by using the ethylene content corresponding to the peak position of the differential molecular weight distribution curve of fraction 1. It was. In addition, B100 and B140 have two reasons for having crystallinity derived from ethylene chain and that the amount of EP contained in these fractions is relatively smaller than the amount of EP contained in fraction 1. Therefore, both approaches to 100 are closer to the actual situation, and almost no errors occur in the calculation. Therefore, analysis is performed with B100 = B140 = 100.

(Iii) The EP content is determined according to the following formula.
EP content (% by weight) = W40 × A40 / B40 + W100 × A100 / 100 + W140 × A140 / 100 (II)
That is, W40 × A40 / B40, which is the first term on the right side of the formula (II), indicates the EP content (% by weight) having no crystallinity, and W100 × A100 / which is the sum of the second term and the third term. 100 + W140 × A140 / 100 indicates the EP content (% by weight) having crystallinity.
Here, average ethylene content A40, A100, A140 of each fraction 1-3 obtained by B40 and CFC measurement is calculated | required as follows.
Fraction 1 fractionated by the difference in crystal distribution is converted into a molecular weight distribution curve by a curve obtained by measuring the molecular weight distribution with a GPC column constituting a part of the CFC analyzer, and FT-IR connected after the GPC column. A corresponding distribution curve of the ethylene content is determined. The ethylene content corresponding to the peak position of the differential molecular weight distribution curve is B40.
Moreover, the sum total of the products of the weight ratio for each data point and the ethylene content for each data point, which are captured as data points during measurement, is the average ethylene content A40.

The significance of setting the three types of fractionation temperatures is as follows.
In the CFC analysis of the present invention, 40 ° C. means only a polymer having no crystallinity (for example, most of EP or extremely low molecular weight component and atactic component among propylene polymer components (PP)). It has the significance of being a temperature condition necessary and sufficient for fractionation. Further, 100 ° C. means a component that is insoluble at 40 ° C. but becomes soluble at 100 ° C. (for example, a component having crystallinity in EP due to a chain of ethylene and / or propylene, and low crystallinity) The temperature is necessary and sufficient to elute only PP). Furthermore, 140 ° C. is a component that is insoluble at 100 ° C. but becomes soluble at 140 ° C. (for example, a component having particularly high crystallinity in PP, and a component having extremely high molecular weight and ethylene crystallinity in EP ) Only, and the temperature is necessary and sufficient to recover the entire amount of the propylene-based block copolymer used for the analysis. Note that the EP component contained in W140 is extremely small and can be substantially ignored.
Ethylene content (% by weight) in EP = (W40 × A40 + W100 × A100 + W140 × A140) / [EP] (III)
However, [EP] is the EP content (% by weight) determined previously.
Of the EP, the ethylene content (E) (% by weight) of the portion having no crystallinity is approximated by the value of B40 since the elution of the rubber portion is almost completed at 40 ° C. or less.

However, in the analysis method based on the combination of the above-described cross fractionation method and FT-IR, the ethylene content of (Y-2) is less than 15 wt%, and there is no significant difference in crystallinity from (Y-1), and the fractionation by temperature However, accurate analysis becomes difficult in cases where this is not sufficient. In such a case, the component (Y-1) is withdrawn during the successive polymerization, the molecular weight (when comonomer is copolymerized, the comonomer content is also measured), and further calculated by material balance. , (Y-1) and (Y-2) by determining the quantity ratio, and by measuring the comonomer content of the entire component (Y) at the end of sequential polymerization, the following simple addition rule of weight: It is preferable to determine the comonomer content of the component (Y-2). When ethylene is used as a comonomer, the ethylene content of (Y-2) is determined by the following formula.
(Y-2) component ethylene content = [(Y) total ethylene content-{(Y-1) component ethylene content x (Y-1) component weight fraction / 100}] / {(Y-2 ) Component weight fraction / 100}

  Regarding other methods for obtaining the amount ratio of the component (Y-1) and the component (Y-2), when producing products having different average molecular weights of the component (Y-1) and the component (Y-2) (Y) After the completion of sequential polymerization, GPC measurement of the whole is performed, the obtained multimodal molecular weight distribution curve is peak-separated using commercially available data analysis software, and the weight ratio is calculated. It is also possible.

Incidentally, a polypropylene resin composition for injection foam molding comprising a propylene-ethylene block copolymer having the same characteristics as described above, another propylene polymer and a foaming agent is disclosed in JP 2010-150509 A. However, when the examples are scrutinized, the other polypropylene polymer uses a propylene-ethylene block copolymer having an MFR of 30 g / 10 min and has a long-chain branched structure disclosed in the present invention. No technical suggestions are given regarding the problem of solving the problems specific to polypropylene.
Japanese Patent Application Laid-Open No. 2010-121054 discloses a propylene-ethylene block copolymer (component B) having the same characteristics as described above, a crystalline polypropylene having a specific MFR (component A), and a specific intrinsic viscosity. Polypropylene polymer (component C) comprising olefin polymer and polypropylene satisfying the range, hydrogenated product of styrene / conjugated diene block copolymer, ethylene-α-olefin copolymer rubber, ethylene polymer resin A polypropylene resin composition with a kind of thermoplastic resin selected is disclosed as a composition suitable for foam blow molding, but even in this case, the problem peculiar to polypropylene having a long chain branched structure is solved. It is understood that there is no technical suggestion about the problem, and it is a technical category different from the present invention. It should.
Further, in Patent Document 10, a propylene homopolymer having an MFR of 10 to 1000 g / 10 min or a propylene-α-olefin copolymer having an α-olefin other than propylene of less than 1% by weight, 50 to 90% by weight, and a weight average It consists of 10 to 50% by weight of a propylene-α-olefin copolymer having a molecular weight of 500,000 to 10 million and an α-olefin content other than propylene of 1 to 15% by weight. A foamed sheet comprising a propylene-based resin composition part having a specific structure is disclosed, but even in this, a specific ultrahigh molecular weight propylene-ethylene copolymer component solves problems peculiar to polypropylene having a long chain branched structure. There is no technical suggestion regarding this issue. Further, when examining the examples, only 3 to 10% by weight of ethylene is disclosed as the α-olefin content of the component having a high molecular weight, and the (Y-2) component ethylene defined in the present invention is disclosed. The content is different. As will be specifically described later in Examples, when the ethylene content of the component (Y-2) is such a value, the polypropylene (X) having a long chain branched structure, which is the object of the present invention, is subjected to shearing. The effect of suppressing the shishi-kebab structure (or its precursor) to be formed is not observed.

VI. Polypropylene resin composition The polypropylene resin composition of the present invention contains 10 to 99% by weight of polypropylene (X) and 1 to 90% by weight of a propylene-based block copolymer (Y), and has a melt tension (MT) measured at 230 ° C. ) Is 1 g or more, and the number of gels having a major axis of 0.5 mm or more is 50 pieces / m ² or less when an unstretched film having a thickness of 25 μm is described above for polypropylene (X). The items are described in detail below in order.

VI-1. Production Method of Resin Composition Known methods can be used as the foam molding polypropylene resin and the foam molding polypropylene resin composition of the present invention. For example, a resin composition can be prepared by mixing a predetermined amount of each of polypropylene (X) and a propylene-based block copolymer (Y) and optional additives described later with a dry blend, a Henschel mixer, or the like. it can. These may be melt kneaded by a single screw extruder, a twin screw kneader, a kneader or the like.
At this time, in order to use for extrusion molding, it is preferable that the resin composition is melt-kneaded and pelletized. As a method of pelletizing the resin composition,
a. A mixture of polypropylene (X), propylene-based block copolymer (Y) and any additive is melt-kneaded and pelletized.
b. A mixture of polypropylene (X) and an optional additive is melt-kneaded and pelletized, and a polypropylene (X) composition pellet is further mixed with a propylene-based block copolymer (Y) and an optional additive, and then melted. Kneaded and pelletized.
b '. A mixture of the propylene-based block copolymer (Y) and an arbitrary additive is melt-kneaded and pelletized, and further mixed with polypropylene (X) and an optional additive, followed by melt-kneading.
c. A mixture of polypropylene (X) and an arbitrary additive and a mixture of propylene-based block copolymer (Y) and an arbitrary additive are each melt-kneaded to obtain each pellet, and each obtained Mix the pellets.
d. A mixture of polypropylene (X) and an arbitrary additive and a mixture of propylene-based block copolymer (Y) and an arbitrary additive are each melt-kneaded to obtain each pellet, and each obtained The pellets are mixed and further melt-kneaded to form pellets.
Such a method can be used.
Here, as a method for pelletizing the resin composition, “the mixture of polypropylene (X) and an arbitrary additive is melt-kneaded and pelletized” described in the above b, c and d. The polypropylene resin for foam molding of the invention can be prepared.

  Here, the polypropylene resin composition of the present invention has a melt tension (MT) measured at 230 ° C. of 1 g or more, preferably 3 g or more, but it is polypropylene (X) and a propylene-based block copolymer. It is the value measured using what melt-kneaded (Y). Therefore, when these are simply mixed and used, or polypropylene (X) and propylene-based block copolymer (Y) are mixed (dry blended) as in c, and both are extruded and foamed without melt kneading. When used as a composition, polypropylene (X), propylene-based block copolymer (Y), and optional components are separately melt-kneaded using the same composition, and MT is measured using the obtained pellets. The value thus obtained is defined as the MT value of the polypropylene resin composition for extrusion foaming. In this case, melt kneading is performed using the method described in the examples described later.

VI-2. Content of polypropylene (X) and propylene block copolymer (Y) The content of polypropylene (X) in the polypropylene resin composition of the present invention is 10 to 99 wt%. When a more preferable range is exemplified, the content of polypropylene (X) is more preferably 10 to 90 wt%, and still more preferably 15 to 80 wt%. Correspondingly, the content of the propylene-based block copolymer (Y) in the polypropylene resin composition is 1 to 90 wt%, preferably 10 to 90 wt%, more preferably 20 to 85 wt% (polypropylene (X)) And the total of the propylene-based block copolymer (Y) is 100 wt%).
By setting the content of polypropylene (X) having a long chain branch to be equal to or higher than the lower limit of the above range, an increase in the open cell ratio of the foamed molded product can be suppressed, and the drawdown can be reduced during thermoforming. . By setting the content of polypropylene (X) to be equal to or lower than the upper limit of the above range, it is possible to maintain high ductility, improve the appearance of the sheet or film, increase the amount of extrusion, and improve productivity. The content of the polypropylene (X) and the propylene-based block copolymer (Y) can be adjusted to a desired content by adjusting the blend amount ratio when making the resin composition.

VI-3. MFR
Preferably, the polypropylene resin composition of the present invention has an MFR of 0.1 to 20 g / 10 min. When a more preferable range is exemplified, the MFR is more preferably 1 to 15 g / 10 minutes, further preferably 2 to 10 g / 10 minutes, and most preferably 3 to 8 g / 10 minutes. By setting the MFR to be equal to or higher than the lower limit of this range, it is possible to improve spreadability, improve the appearance of the sheet or film, increase the amount of extrusion, and improve productivity. By setting the MFR to be equal to or lower than the upper limit of this range, it is possible to suppress an increase in the open cell ratio of the foamed molded product, to keep the bubble size uniform, and to suppress drawdown during thermoforming.
There are several ways to adjust the MFR within the above range. For example, the MFR of the polypropylene resin composition can be adjusted by adjusting the MFR of polypropylene (X) or the propylene-based block copolymer (Y). Moreover, when MFR of polypropylene (X) and a propylene-type block copolymer (Y) differs, MFR of a polypropylene resin composition can be adjusted also by changing the compounding quantity of both. For example, when the MFR of polypropylene (X) is higher than the MFR of propylene-based block copolymer (Y), increasing the blending amount of polypropylene (X) increases the MFR of the polypropylene resin composition.

VI-4. Melt tension (MT)
The polypropylene resin composition of the present invention must have a melt tension (MT) measured at 230 ° C. of 1 g or more. Preferably it is 1.5 g or more, more preferably 2 g or more, most preferably 3 g or more, preferably 20 g or less, more preferably 15 g or less, and most preferably 10 g or less. Here, MT of a polypropylene resin composition is a value obtained using the same measuring method as the melt tension (MT) of the characteristic (X-ii) of polypropylene (X). By setting the MT to be equal to or higher than the lower limit of the above value, it is possible to keep the formation and growth of the cells at the time of foaming well, suppress the increase of the open cell ratio, and make the cell size uniform. By setting MT below the upper limit of the above value, the spreadability can be improved, the appearance of the sheet or film can be improved, the amount of extrusion can be increased, and the productivity can be improved.
There are several ways to adjust MT within the above range. For example, the MT of polypropylene (X) may be changed, or it can be adjusted by changing the blending amount of polypropylene (X) and propylene block copolymer (Y). Generally, when the content of polypropylene (X) is increased, the MT of the resin composition can be increased.

VI-5. Propylene (co) polymer (H)
In particular, in fields where high melt tension is required, such as foam molding, it is required to use a resin composition having a high melt tension by further diluting with another resin from the viewpoint of achieving both physical properties of the product and economy. There are many cases.
In the polypropylene resin composition of the present invention, the constituent components polypropylene (X) and propylene-based block copolymer (Y) are responsible for improving the foaming performance of each, and the resin that inhibits them. Dilution inhibits the effect of the present invention.
Therefore, it is preferable to use other resins for dilution as long as the effects of the present invention are not significantly impaired. In the polypropylene resin composition of the present invention, the polypropylene (X) and the propylene-based block copolymer (Y) are organically influenced to express a high effect on foaming performance. Even if diluted, it is easy to maintain a high effect.

In the present invention, a preferable resin used for dilution for improving economic efficiency while maintaining foaming performance is at least selected from the group consisting of a propylene homopolymer, or ethylene and an α-olefin having 4 to 10 carbon atoms. When the propylene (co) polymer (H) is a copolymer of one kind of olefin and propylene and the propylene (co) polymer (H) is a copolymer, ethylene in the propylene (co) polymer (H) and α- A propylene (co) polymer (H) having an olefin content of more than 0 and 3 wt% or less is preferred.
This is a dilution of the propylene (co) polymer (H) having the same performance as the propylene (co) polymer (Y-1) contained in the propylene-based block copolymer (Y), which is a constituent of the present invention. If used as a material, the content of the propylene-ethylene copolymer (Y-2) in the polypropylene (X) and the propylene-based block copolymer (Y) in the diluted resin composition is determined by the resin of the present invention. This is based on the fact that the foaming characteristics are not deteriorated when it can be maintained within the range of the composition.
On the other hand, when other propylene-based block copolymers or polyethylene resins that do not satisfy the requirements of the propylene-based block copolymer (Y) according to the present invention are used as a diluent, they are propylene-based block copolymers ( Since the improvement effect of the propylene-ethylene copolymer (Y-2) in Y) may be hindered and the effects of the present invention may be significantly hindered, care must be taken in the selection of the diluent.
Whether or not the effect of the present invention is remarkably hindered is, for example, whether or not the open cell ratio shows a value about three times that when the diluent is used and when the diluent is not used. Can be.

  The blending amount of the propylene (co) polymer (H) is preferably 0.1 to 1000 parts by weight, more preferably 1 to 500 parts by weight, still more preferably 10 to 300 parts by weight with respect to 100 parts by weight of the polypropylene resin composition. Part. The content of the polypropylene (X) in the diluted resin composition and the propylene-ethylene copolymer (Y-2) in the propylene-based block copolymer (Y) can be maintained within the prescribed range of the polypropylene resin composition. The range is preferable, and the proportion of (Y-2) in the polypropylene resin composition is preferably 0.01 to 47.5 wt%, more preferably 1 to 36 wt%, based on the total amount of X, Y and H Further, it is preferable to determine the blending amount of the propylene (co) polymer (H) so as to be 4 to 25.5 wt%.

VI-6. Additives Various additives can be blended as optional components in the polypropylene resin composition of the present invention. Specifically, antioxidants, ultraviolet absorbers, light stabilizers, metal deactivators, stabilizers, neutralizers, lubricants, antistatic agents, antifogging agents, used as conventional polyolefin resin compounding agents, Various additives such as a nucleating agent, a peroxide, a filler, an antibacterial and antifungal agent, and a fluorescent brightening agent can be added as long as the effects of the present invention are not impaired. The amount of these additives is generally 0.0001 to 3 wt%, preferably 0.001 to 1 wt% in 100 wt% of the resin composition.

First, the antioxidant will be described.
Oxidative degradation of polyolefin is a radical chain reaction via peroxide radicals and hydroperoxide compounds generated by the action of heat, light, mechanical force, metal ions, etc. and oxygen, and is generally called auto-oxidation. . Antioxidants are used to suppress this auto-oxidation, and there are three types of phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants depending on where they act in the chain reaction. It is common to be separated.
A phenolic antioxidant is a radical scavenger, and since radicals generated by reaction with peroxide radicals and the like are relatively stable, the radical concentration in the system can be lowered. In general, a substituted phenol compound, particularly a substituted phenol compound having a bulky substituent at the ortho position is used.

Hereinafter, typical compounds are exemplified as the phenolic antioxidant.
In the monophenol type compound, 2,6-di-t-butyl-4-methylphenol (common name: BHT), tocopherol (vitamin E), n-octadecyl-3- (4′-hydroxy-3 ′, 5 ′) -Di-t-butylphenyl) propionate (trade name: Irganox 1076, Sumilizer BP-76) can be exemplified.
Among the bisphenol type compounds, 2,2′-methylenebis (4-methyl-6-tert-butylphenol) (trade name: Sumilizer MDP-S), 1,1-bis (2′-methyl-4′-hydroxy-5) '-T-Butylphenyl) butane (trade name: Sumilizer BBM-S, Adekastab AO-40), 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) Propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane (trade names: Smither GA-80, Adeka Stab AO-80) can be exemplified.
Among the triphenol type compounds, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane (trade name: ADK STAB AO-30), 1,3,5-trimethyl-2 , 4,6-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (trade name: Irganox 1330, Adeka Stab AO-330), Tris- (3,5-di-t-butyl-4- Hydroxybenzyl) -isocyanurate (trade name: Irganox 3114, Adeka Stab AO-20), 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate (trade name: Sumilyzer) BP-179, Cyanox 1790), tris- (3,5-di-tert-butyl-4-hydroxyphenyl) -isocyanu Over door (trade name: Keminokkusu 314) can be exemplified.
Examples of the tetraphenol type compound include tetrakis {methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate} methane (trade name: Irganox 1010).

  The phosphorus-based antioxidant has an action of reducing the hydroperoxide compound and is also called a hydroperoxide decomposing agent. Although it has an antioxidant effect by itself, when used in combination with the above-mentioned phenolic antioxidant, a synergistic effect is generated and the antioxidant effect is further enhanced. Therefore, both are usually used in combination. This synergistic effect occurs because the phenolic antioxidant regenerates by reducing the phenoxy radical species generated by the reaction between the phenolic antioxidant and the radical species involved in autoxidation by the phosphorus antioxidant. It is believed that.

Hereinafter, typical compounds are exemplified as the phosphorus-based antioxidant.
Among the phosphite-type compounds, tris (2,4-di-t-butylphenyl) phosphite (trade name: Irgafos 168, Sumilizer P-16, Adekastab 2112), trisnonylphenyl phosphite (trade name: Sumilyzer TNP, Adekastab) 1178), tris (mixed, mono-dinonylphenyl phosphite) (trade name: ADK STAB 329K), tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene diphosphonite (common name: P-EPQ) and cyclic neopentanetetraylbis (2,6-di-t-butyl-4-methylphenyl phosphite) (trade name: ADK STAB PEP-36).

Sulfur-based antioxidants, like phosphorus-based antioxidants, have the effect of reducing hydroperoxide compounds and are also called hydroperoxide decomposing agents. This is also said to have a synergistic effect in combination with a phenolic antioxidant as well as a phosphorus antioxidant.
Hereinafter, typical compounds are exemplified as the sulfur-based antioxidant.
In the sulfide type compound, dilauryl-3,3′-thio-dipropionate (common name: DLTDP), di-myristyl-3,3′-thio-dipropionate (common name: DMTDP), distearyl-3,3′-thio- Examples thereof include dipropionate (common name: DSTDP), pentaerythritol-tetrakis- (3-laurylthio-propionate) (trade name: Sumilizer TP-D, ADK STAB AO-412S).

Next, the ultraviolet absorber and the light stabilizer will be described.
Additives for suppressing photodegradation are ultraviolet absorbers and light stabilizers. When polypropylene is exposed to ultraviolet rays, radicals are generated and auto-oxidation occurs. The ultraviolet absorber has an action of suppressing generation of radicals by absorbing ultraviolet rays, and the light stabilizer has an action of capturing and inactivating radicals generated by ultraviolet rays.
The ultraviolet absorber is a compound having an absorption band in the ultraviolet region, and triazole, benzophenone, salicylate, cyanoacrylate, nickel chelate, inorganic fine particle, and the like are known. Of these, the triazole type is most widely used.
Hereinafter, typical compounds are exemplified as the ultraviolet absorber.
Among triazole-based compounds, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole (trade name: Sumisorb 200, TinuvinP), 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole (Trade names: Sumisorb 340, Tinuvin 399), 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole (trade names: Sumisorb 320, Tinuvin 320), 2- (2′-hydroxy) -3 ′, 5′-di-t-amylphenyl) benzotriazole (trade names: Sumisorb 350, Tinuvin 328), 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5 Chlorobenzotriazole (trade name: Sumisorb 300, Tinuvin 326) wear.
Examples of benzophenone-based compounds include 2-hydroxy-4-methoxybenzophenone (trade name: Sumisorb 110) and 2-hydroxy-4-n-octoxybenzophenone (trade name: Sumisorb 130).
Examples of salicylate compounds include 4-t-butylphenyl salicylate (trade name: Seesorb 202). Examples of cyanoacrylate compounds include ethyl (3,3-diphenyl) cyanoacrylate (trade name: Seesorb 501). Examples of the nickel chelate compound include nickel dibutyldithiocarbamate (trade name: Antigen NBC). Examples of inorganic fine particle compounds include TiO ₂ , ZnO ₂ , and CeO ₂ .

The light stabilizer is generally a hindered amine compound and is called HALS. HALS has a 2,2,6,6-tetramethylpiperidine skeleton and cannot absorb ultraviolet rays, but suppresses photodegradation by various functions. The main functions are said to be three of: scavenging radicals, decomposing hydroxy peroxide compounds, and capturing heavy metals that accelerate the decomposition of hydroxy peroxides.
Hereinafter, typical compounds are exemplified as HALS.
In the sebacate type compound, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (trade name: ADK STAB LA-77, Tinuvin 770), bis (1,2,2,6,6-pentamethyl- 4-piperidyl) sebacate (trade name: Tinuvin 765) can be exemplified.
Among the butanetetracarboxylate type compounds, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (trade name: ADK STAB LA-57), tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (trade name: ADK STAB LA-52), 1,2,3,4-butanetetra Condensation product of carboxylic acid with 2,2,6,6-tetramethyl-4-piperidinol and tridecyl alcohol (trade name: Adeka Stab LA-67), 1,2,3,4-butanetetracarboxylic acid and 1, A condensate of 2,2,6,6-pentamethyl-4-piperidinol and tridecyl alcohol (trade name: Adeka Stab LA-62) can be exemplified. .
Examples of the succinic polyester type compound include a condensation polymer of succinic acid and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine.
In the triazine type compound, N, N′-bis (3-aminopropyl) ethylenediamine · 2,4-bis {N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino } -6-Chloro-1,3,5-triazine condensate (trade name: Chimassorb 199), poly {6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2 , 4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino} (trade name: Chimassorb 944) ), Poly (6-morpholino-s-triazine-2,4-diyl) {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-teto Lamethyl-4-piperidyl) imino} (trade name: Chimasorb 3346).

Some other additives are also exemplified.
A lubricant is an additive used to improve moldability and fluidity, and has the effect of reducing the frictional force between polymer molecules and the frictional force between the polymer and the inner wall of the molding machine in a molding machine or extruder. . Compounds used as lubricants include hydrocarbon compounds such as paraffin and wax, alcohols such as stearyl alcohol and propylene glycol, higher fatty acid esters such as n-butyl stearate, higher fatty acid amides such as oleic acid amide and stearic acid amide, stear Examples include higher fatty acid salts such as calcium phosphate, partial esters of polyhydric alcohols such as stearic acid monoglyceride, and silicone oil.
Among these, specific examples of the higher fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, and behenic acid amide. The fatty acid amide compound may have a substituent on the alkyl chain or N. Examples of the fatty acid amide compound having a substituent include hydroxy stearic acid amide, N-oleyl palmitic acid amide, N-stearyl oleic acid amide, N-stearyl erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, Can be mentioned.

The stabilizer is an additive for polyvinyl chloride (PVC) in the first place, and is used for the purpose of preventing degradation of hydrochloric acid (HCl) from PVC. Some of the various stabilizers also have a function as a neutralizing agent, and thus may be used as an additive for polyolefins.
A neutralizing agent is a compound used to neutralize chlorine components derived from Ziegler catalysts used in the production of polyolefins. As the neutralizing agent, a carboxylate having a neutralizing ability is often used, but an inorganic compound having a chlorine ion capturing ability can also be used. Both are compounds used as stabilizers. Basically, when using a metallocene catalyst that does not contain a chlorine atom, it is an additive that is not originally necessary, but since chlorine is a chemical species that easily contaminates, it is used for insurance from the viewpoint of stable production. It is often done.
Hereinafter, typical compounds are exemplified as the neutralizing agent.
Examples of the carboxylate type compound include calcium stearate and zinc stearate. Examples of inorganic compounds include hydrotalcite and inclusions of aluminum hydroxide and lithium carbonate (trade name: Mizukarak).

VII. Extrusion Foam Molding, Polypropylene Foam Sheet, Thermoformed Body The foam resin for foam molding and the polypropylene resin composition for foam molding of the present invention can be used for extrusion molding, injection molding, thermo molding, calender molding, press molding, and the like. However, it is particularly suitable for various types of extrusion foaming because it has excellent bubble retention and has good melt tension and good spreadability. The type of extrusion foaming used is not particularly limited.
Typical extrusion foam molding includes foam molding by foam sheet molding, foam film molding, foam blow molding, bead foam molding, and the like. In the case of foam sheet molding, a known combination of an extruder and a die can be used.
The extruder may be uniaxial or biaxial. The die may be a T die or a circular shape (circular). The same applies to foam film formation. In the case of foam film formation, stretching may be further performed. As the stretching method, a known method can be used without limitation. For example, a tubular method, a tenter type stretching method, a roll stretching method, a pantograph type batch stretching method, and the like can be exemplified. Also in the case of foam blow molding, a known method may be used. Specific examples include a direct blow molding machine and an accumulative blow molding machine.
Details will be described in order below.

VII-1. Foaming agent When performing extrusion foaming using the polypropylene resin composition of the present invention, it is necessary to use a foaming agent. At this time, the type of the foaming agent is not particularly limited, and a known foaming agent used for plastics, rubber, and the like can be used. There are no particular restrictions on the type of foaming agent, and any type such as a physical foaming agent, a degradable foaming agent (chemical foaming agent), or a microcapsule containing a thermal expansion agent may be used.

Specific examples of physical blowing agents include aliphatic hydrocarbons such as propane, butane, pentane and hexane, alicyclic hydrocarbons such as cyclopentane and cyclohexane, chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane, and dichloromethane. Difluoromethane, chloromethane, dichloromethane, chloroethane, dichlorotrifluoroethane, dichlorofluoroethane, chlorodifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, trichlorotrifluoroethane, dichlorotetrafluoroethane Illustrative of halogenated hydrocarbons such as chloropentafluoroethane and perfluorocyclobutane, inorganic gases such as water, carbon dioxide and nitrogen Rukoto can. These compounds may be used alone or in combination with a plurality of compounds.
Among these, aliphatic hydrocarbons such as propane, butane, and pentane and carbon dioxide are preferable because they are inexpensive and have high solubility in the polypropylene resin (X). In particular, when carbon dioxide gas is used, supercritical conditions of 7.4 MPa or more and 31 ° C. or more are more preferable because the state of diffusion and solubility in the polymer is excellent.

When a physical foaming agent is used, a bubble regulator can be used as necessary. Examples of the air conditioner include inorganic decomposable foaming agents such as ammonium carbonate, sodium bicarbonate, ammonium bicarbonate and ammonium nitrite, azo compounds such as azodicarbonamide, azobisisobutyronitrile and diazoaminobenzene, N, N′- Nitroso compounds such as dinitrosopentanemethylenetetramine and N, N'-dimethyl-N, N'-dinitrosotephthalamide, benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, p, p'-oxybisbenzenesulfonyl semicarbazide, p- Degradable foaming agents such as toluenesulfonyl semicarbazide, trihydrazinotriazine, barium azodicarboxylate, inorganic powders such as talc and silica, acid salts such as polyvalent carboxylic acids, reaction of polyvalent carboxylic acids with sodium carbonate or sodium bicarbonate Examples of mixtures etc. It is possible. These bubble regulators may be used alone or in combination.
When using the cell regulator, the blending amount of the cell regulator is 0.01 to 5 wt.% Pure with respect to a total of 100 parts by weight of the polypropylene (X) and the propylene-based block copolymer (Y). It is preferable to set the range of parts.

Specific examples of degradable foaming agents (chemical foaming agents) include a mixture of sodium bicarbonate and an organic acid such as citric acid, an azo foaming agent such as azodicarbonamide and barium azodicarboxylate, and N, N′-dinitrosopentamethylene. Nitroso blowing agents such as tetramine, N, N′-dimethyl-N, N′-dinitrosotephthalamide, sulfohydrazide blowing agents such as p, p′-oxybisbenzenesulfonyl hydrazide, p-toluenesulfonyl semicarbazide, tri And hydrazinotriazine.
The blending amount of the foaming agent is preferably in the range of 0.05 to 6.0 parts by weight, more preferably 0.000 parts by weight with respect to 100 parts by weight in total of the polypropylene (X) and the propylene-based block copolymer (Y). 05 to 3.0 parts by weight, more preferably 0.5 to 2.5 parts by weight, and particularly preferably 1.0 to 2.0 parts by weight.

VII-2. Polypropylene Resin Foam Molded Article The polypropylene resin foam molded article of the present invention is produced by using the polypropylene resin for foam molding and the polypropylene resin composition for foam molding of the present invention. In the present invention, the shape and molding method of the polypropylene resin foam molding are not limited. The polypropylene resin foam molded article of the present invention is preferably a sheet, but the thickness of the foamed sheet is preferably about 0.3 mm to 10 mm. More preferably, it is 0.5 mm to 5 mm.
Polypropylene-based foamed sheets are secondarily processed by thermoforming, and are widely used in industry mainly in various containers. Polypropylene-based foam sheets are widely used in various applications with the advantage of being lightweight.
Here, since the polypropylene foam sheet contains many bubbles (cells) in the sheet, if the cells are rough or irregular, they appear on the surface of the sheet, which deteriorates the surface appearance and has a commercial value. It will decline. Furthermore, when thermoforming is performed, it is necessary to heat the mold sufficiently to transfer the mold, but in the foamed sheet, the cell also expands when heated. As a result, if the foam cell is rough, the surface tends to deteriorate, and if the foam cell is not uniform, the sheet is torn during heating.
In order to solve these problems, it is considered necessary to form a foam cell having a high closed cell ratio, a dense and uniform size. By using the composition, these are realized, and as the foam sheet, a sheet having excellent appearance and high thermoformability can be obtained.

VII-3. Polypropylene resin multilayer foam sheet When producing a polypropylene resin foam sheet, a multilayer foam sheet may be used.
Specifically, the foamed layer using the polypropylene resin for foam molding or the polypropylene resin composition for foam molding of the present invention and the non-foamed layer made of the thermoplastic resin composition may be coextruded. At this time, a known co-extrusion method using a feed block or a multi-die using a plurality of extruders can be used.
The non-foamed layer used in the polypropylene resin multilayer foamed sheet using the polypropylene resin for foam molding or the polypropylene resin composition for foam molding of the present invention for the foamed layer may be provided on any surface of the foamed layer, It can also be set as the structure (sandwich structure) which made the foaming layer exist between non-foaming layers.

The thickness of the polypropylene resin multilayer foam sheet is not particularly limited, but is preferably about 0.3 mm to 10 mm. More preferably, it is 0.5 mm-5 mm.
Moreover, the thickness of the non-foamed layer in the polypropylene-based multilayer foamed sheet is 1 to 50% of the total thickness of the obtained polypropylene-based multilayer foamed sheet, more preferably 5 to 20 so as not to hinder the growth of bubbles in the foamed layer. It is desirable to form so that it may become%.

  The polypropylene resin multilayer foam sheet provided with a non-foamed layer is excellent in strength, and at least the outer surface of the foamed layer is provided with a non-foamed layer, so that the surface smoothness and appearance are also excellent. Become. Furthermore, by using a functional thermoplastic resin for the non-foamed layer, it is possible to easily combine the polypropylene-based multilayer foam sheet with additional functions such as antibacterial properties, soft feeling, and scratch resistance. preferable.

As the thermoplastic resin constituting the thermoplastic resin composition used for the non-foamed layer, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, and propylene-α can be used as long as the effects of the present invention are not impaired. -Olefin copolymers, polyolefins such as poly-4-methyl-pentene-1, olefinic elastomers such as ethylene-propylene elastomer, or other monomers copolymerizable therewith, such as vinyl acetate, vinyl chloride, (meta ) Copolymers and mixtures such as acrylic acid and (meth) acrylic acid esters can be selected.
Among these, polypropylene and propylene-α-olefin copolymers are preferable from the viewpoints of recyclability, adhesiveness, heat resistance, oil resistance, rigidity, and the like. As propylene-α-olefin copolymer, propylene-based block copolymer obtained by multi-stage polymerization of propylene (co) polymer and ethylene-propylene random copolymer using multiple or single polymerization tanks. Includes coalescence.
Among these, since the propylene-based block copolymer is excellent in the balance between rigidity and impact resistance, it is more preferable, and the propylene-based block copolymer (provided that the propylene-based block copolymer (Y) satisfies the requirements to be satisfied (however, When the polypropylene resin composition containing (Y) may be the same as or different from (Y) is used for the non-foamed surface layer, the obtained sheet has a good surface appearance and heat. Since it has the characteristic that the retainability of the cell at the time of shaping | molding is high, it is the most suitable. At this time, the content of the propylene-based block copolymer in the polypropylene resin composition used for the non-foamed surface layer is preferably 0.1 to 100% by weight.

In particular, when used as a thermoformed product, the rigidity of the molded product is very important. To improve this, a non-foamed layer is provided on the surface layer, and an inorganic filler is provided on the non-foamed layer. It is preferable to mix. In the thermoplastic resin composition used as the non-foamed layer, it is desirable to blend 50 parts by weight or less of the inorganic filler with respect to 100 parts by weight of the thermoplastic resin. When the amount exceeds 50 parts by weight, the surface of the sheet is liable to be damaged due to the occurrence of scraping at the die outlet.
Examples of the inorganic filler include talc, calcium carbonate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate and the like.

VII-4. Thermoformability Although the polypropylene foam sheet and the polypropylene multilayer foam sheet in the present invention have high thermoformability, they can be evaluated by performing a sag test. The sag test is a test method in which a sheet is heated with a heater as in thermoforming, and the behavior of the sheet at that time is observed. The behavior of the sheet in the sag test is as follows.
First, when the sheet is heated, it softens and expands, and the sheet once hangs down. During this time, the crystal melting is not yet sufficient, the extensibility is insufficient at the time of thermoforming, and the mold shape cannot be transferred sufficiently. When heating progresses and crystal melting is sufficient, the sheet once hung down contracts due to relaxation of residual stress during sheet forming, and stretches back to the position at the time of heating. At this time, the crystal is sufficiently melted and the residual stress is released, so that a molded body in which the mold is sufficiently transferred can be obtained at the time of thermoforming. As the heating further proceeds, the viscosity decreases as the sheet temperature rises and begins to sag due to its own weight or cell expansion, and eventually begins to open holes. If the hole is opened, it is of course impossible to obtain a molded body by thermoforming, and even if the hole is not opened, if the sag is large, it will be in contact with the mold and the molded body cannot be obtained.
In the above behavior, the range in which thermoforming is possible is within the range from time T1 when the sheet is stretched back to time T2 until the hole is opened. The wider the time width, the wider the moldable range. T2-T1 can be obtained and used for the evaluation of thermoformability. At this time, in this time range, the smaller the sag, the easier it is to perform thermoforming, and the larger molded body can be molded. Therefore, the sag amount D (T2) at T2 is divided by (T2-T1). Thus, it is defined as an average sag velocity VD [mm / s] in a moldable range, and this can also be used for evaluation of thermoformability.

As for the state of the foamed cell, a state where the size of the cell is small and dense, the size is uniform, and high independence is preferable. Specifically, the foam layer bubble diameter is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less. When the bubble diameter of the foamed layer greatly exceeds 500 μm, an appearance defect such as perforation may occur on the thermoformed article when the polypropylene foam sheet or the sheet is thermoformed, which is not preferable. In addition, let the bubble diameter of a foam layer be the value calculated | required using the optical microscope by the method as described in an Example.
The cell independence can be determined by the open cell ratio. The open cell ratio is preferably 30% or less, more preferably 20% or less, and still more preferably 15% or less. When the open cell ratio exceeds 30%, the expansion of the foamed cells in the foamed sheet does not occur during thermoforming, which may reduce the thickness of the thermoformed body, which is not preferable. Moreover, since it may lead also to the fall of the heat insulation performance of a thermoformed object, it is unpreferable.
In addition, let open-cell rate be the value calculated | required using the air pycnometer (made by Tokyo Science Co., Ltd.) by the method as described in an Example.

VII-5. Thermoformed body The thermoformed body of the present invention is obtained by thermoforming the above-mentioned polypropylene resin foam sheet or polypropylene resin multilayer foam sheet.
The thermoforming method is not particularly limited. For example, plug molding, matched molding, straight molding, drape molding, plug assist molding, plug assist reverse draw molding, air slip molding, snapback molding, reverse draw. Examples thereof include molding, free drawing molding, plug-and-ridge molding, and ridge molding.

VII-6. Applications The polypropylene resin foam molded article, foam sheet and thermoformed article of the present invention have uniform fine foam cells, and have appearance, thermoformability, impact resistance, light weight, rigidity, heat resistance, heat insulation, oil resistance. Therefore, it can be suitably used for food containers such as trays, dishes and cups, vehicle interior materials such as automobile door trims and automobile trunk mats, packaging, stationery and building materials.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

1. Measuring method of various physical properties The characteristics of the polypropylene resin composition comprising polypropylene (X), polypropylene (X) and a propylene-based block copolymer were measured by the following methods.
1.1. Melt flow rate (MFR)
Measured in accordance with JIS K7210: 1999, Method A, Condition M (230 ° C., 2.16 kg load). The unit is g / 10 minutes.
1.2. Melt tension (MT)
It measured on the following conditions using the Toyo Seiki Seisakusho Capillograph.
・ Capillary: Diameter 2.0mm, length 40mm
・ Cylinder diameter: 9.55mm
・ Piston extrusion speed: 20 mm / min ・ Pickup speed: 4.0 m / min ・ Temperature: 230 ° C.
When the MT is extremely high, the resin may break at a take-up speed of 4.0 m / min. In such a case, the take-up speed is lowered and the tension at the highest speed at which the take-up can be taken is MT. And The unit is gram.

1.3. Ratio of xylene-soluble components at C.25 ° C. (CXS)
CXS values were obtained using the following method.
A 2 g sample is dissolved in 300 mL of p-xylene (containing 0.5 mg / mL BHT) at 130 ° C. to make a solution, and then left at 25 ° C. for 12 hours. Thereafter, the precipitated polymer is separated by filtration, p-xylene is evaporated from the filtrate, and further dried under reduced pressure at 100 ° C. for 12 hours to recover a 25 ° C. xylene-soluble component. The ratio [wt%] of the weight of the recovered component to the charged sample weight is defined as CXS.
1.4. Branch index g '
Using a GPC equipped with a differential refractometer (RI), a viscosity detector (Viscometer), and a light scattering detector (MALLS) as detectors, a branching index g ′ when the absolute molecular weight Mabs was 1 million was determined. The specific measurement method, analysis method, and calculation method are as described above.
1.5. Strain hardening degree (λmax)
The elongational viscosity was measured using Ales manufactured by Rheometrics, and the strain hardening degree (λmax) was obtained from the result. The specific measurement method and calculation method are as described above.

1.6. Isotactic triad fraction (mm fraction), presence / absence of long-chain branching As described above, using JSX Corporation, GSX-400, FT-NMR, paragraphs [0025]-[ [0065]. The unit of mm fraction is%.
1.7. Melting point:
Using a differential operating calorimeter (DSC), once the temperature was raised to 200 ° C. and the heat history was erased, the temperature was lowered to 40 ° C. at a rate of 10 ° C./min, and again the temperature rising rate was 10 ° C./min. The temperature at the top of the endothermic peak was measured as the melting point.

1.8. Molecular weight distributions Mw / Mn and Mz / Mn:
It calculated | required by the following GPC measurement.
Apparatus: GPC manufactured by Waters (ALC / GPC 150C)
Detector: MIRAN 1A IR detector manufactured by FOXBORO (measurement wavelength: 3.42 μm)
Column: Showa Denko AD806M / S (3 in series)
-Mobile phase solvent: orthodichlorobenzene (ODCB)
・ Measurement temperature: 140 ℃
・ Flow rate: 1.0 ml / min
・ Injection volume: 0.2ml
Sample preparation: Prepare a 1 mg / mL solution using ODCB (containing 0.5 mg / mL BHT) and dissolve it at 140 ° C. for about 1 hour.
Conversion from the retention capacity obtained by GPC measurement to the molecular weight is performed using a calibration curve prepared in advance by standard polystyrene (PS). The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is created by injecting 0.2 mL of a solution dissolved in ODCB (containing 0.5 mg / mL BHT) so that each is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximation by the least square method.
In addition, 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

1.9. Ratio of propylene (co) polymer (Y-1) and propylene-ethylene copolymer (Y-2), ethylene content in Y-2 Combination of cross fractionation method and FT-IR method described in the specification The method was determined.

1.10. Intrinsic viscosity of propylene-ethylene copolymer (Y-2) 1.3. The intrinsic viscosity was measured using the CXS component of the propylene-based block copolymer (Y) obtained by the method described in 1. above. The intrinsic viscosity was measured using an Ubbelohde capillary viscometer at a temperature of 135 ° C. and a decalin solvent.

1.11. Characteristic evaluation of foam sheet The characteristic evaluation of the foam sheet was carried out by the following method.
1.11.1. Density A test piece was cut out from the foamed sheets obtained in Examples and Comparative Examples, and the test piece weight (g) was obtained by dividing by the volume (cm ³ ) determined from the outer dimensions of the test piece. The density was determined by measuring according to JIS K7222.
1.12. Foaming ratio A value obtained by dividing the density of the polypropylene resin 0.9 g / cm ³ by the density of the above-mentioned foamed sheet test piece was defined as the foaming ratio.
1.13. Appearance Evaluation of Sheet The evaluation of the appearance of the foam sheet was performed by evaluating the polypropylene resin foam sheets obtained in the respective Examples and Comparative Examples according to the following criteria.
A: There are very few thickness spots and it is smooth. There are no local irregularities on the surface and it is beautiful. Bubble shape is fine.
○: There are few thickness spots. There are almost no local irregularities on the surface. Bubble shape is uniform.
Δ: There are thick spots. Bubble shape is uniform, but local irregularities are seen.
X: There are many thickness spots. Bubbles are coalesced and there are local depressions.

1.14. Foamed layer cell diameter A 25 mm square sample was cut out from the foamed sheets obtained in the examples and comparative examples. Using a stereomicroscope (Nikon: SMZ-1000-2 type), the foam layer cross section is enlarged and projected, and from the number of bubbles and the bubble diameter in the cross section, the bubble diameter of the cross section in the extrusion direction and the cross section in the vertical direction are calculated. The average value was taken as the foam layer bubble diameter of the foam layer.
1.15. Open cell ratio Test pieces were cut out from the foamed sheets obtained in Examples and Comparative Examples, and measured according to the method described in ASTM D2856 using Air Pycnometer (manufactured by Tokyo Science Co., Ltd.).

2. Materials used 2.1. Polypropylene (X)
Polypropylene: X1 to X3 obtained in the following Production Examples 1 to 3, and homopolypropylene Dapploy (TM) WB140HMS: X4 manufactured by Borealis were used as polypropylene (X).

[Production Example 1: Production of polypropylene (X1)]
<Synthesis of catalyst component [A-1]>
Synthesis of dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl}] hafnium: (component [A-1] (complex 1 ) Synthesis):
(I) Synthesis of 4- (4-i-propylphenyl) indene To a 500 ml glass reaction vessel, 15 g (91 mmol) of 4-i-propylphenylboronic acid and 200 ml of dimethoxyethane (DME) were added, and 90 g of cesium carbonate ( 0.28 mol) and 100 ml of water were added, 13 g (67 mmol) of 4-bromoindene and 5 g (4 mmol) of tetrakistriphenylphosphinopalladium were added in this order, and the mixture was heated at 80 ° C. for 6 hours.
After allowing to cool, the reaction solution was poured into 500 ml of distilled water, transferred to a separatory funnel, and extracted with diisopropyl ether. The ether layer was washed with saturated brine and dried over sodium sulfate. Sodium sulfate was filtered, the solvent was distilled off under reduced pressure, and the residue was purified by a silica gel column to obtain 15.4 g (yield 99%) of 4- (4-i-propylphenyl) indene as a colorless liquid.

(Ii) Synthesis of 2-bromo-4- (4-i-propylphenyl) indene In a 500 ml glass reaction vessel, 15.4 g (67 mmol) of 4- (4-i-propylphenyl) indene, 7.2 ml of distilled water DMSO (200 ml) was added, and N-bromosuccinimide (17 g, 93 mmol) was gradually added thereto. The mixture was stirred at room temperature for 2 hours, poured into 500 ml of ice water, and extracted three times with 100 ml of toluene. The toluene layer was washed with saturated brine, 2 g (11 mmol) of p-toluenesulfonic acid was added, and the mixture was heated to reflux for 3 hours while removing moisture. The reaction mixture was allowed to cool, washed with saturated brine, and dried over sodium sulfate. Sodium sulfate was filtered, the solvent was distilled off under reduced pressure, and the residue was purified with a silica gel column to obtain 19.8 g (yield 96%) of 2-bromo-4- (4-i-propylphenyl) indene as a yellow liquid. .

(Iii) Synthesis of 2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indene To a 500 ml glass reaction vessel, 6.7 g (82 ml mol) of 2-methylfuran and 100 ml of DME were added. The solution was cooled to -70 ° C in a dry ice-methanol bath. 1 here
. A 59 mol / L n-butyllithium-n-hexane solution (51 ml, 81 mmol) was added dropwise, and the mixture was stirred for 3 hours. The solution was cooled to −70 ° C., and a solution of 20 ml (87 mmol) of triisopropyl borate and 50 ml of DME was added dropwise thereto. After dropping, the mixture was stirred overnight while gradually returning to room temperature.
The reaction solution was hydrolyzed with 50 ml of distilled water, and then a solution of 223 g of potassium carbonate and 100 ml of water and 19.8 g (63 mmol) of 2-bromo-4- (4-i-propylphenyl) indene were added in that order at 80 ° C. The mixture was heated and reacted for 3 hours while removing low-boiling components.
After allowing to cool, the reaction solution was poured into 300 ml of distilled water, transferred to a separatory funnel and extracted three times with diisopropyl ether. The ether layer was washed with saturated brine and dried over sodium sulfate. Sodium sulfate was filtered off, the solvent was distilled off under reduced pressure, and the residue was purified with a silica gel column to obtain 19.6 g of 2- (2-methyl-5-furyl) -4- (4-i-propylphenyl) indene as a colorless liquid ( Yield 99%).

(Iv) Synthesis of dimethylbis (2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl) silane In a 500 ml glass reaction vessel, 2- (5-methyl-2- Furyl) -4- (4-i-propylphenyl) indene (9.1 g, 29 mmol) and THF (200 ml) were added, and the mixture was cooled to -70 ° C in a dry ice-methanol bath. To this, 17 ml (28 mmol) of a 1.66 mol / L n-butyllithium-hexane solution was added dropwise and stirred as it was for 3 hours. The mixture was cooled to −70 ° C., 0.1 ml (2 mmol) of 1-methylimidazole and 1.8 g (14 mmol) of dimethyldichlorosilane were sequentially added, and 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, and sodium sulfate was added to dry the reaction solution. Sodium sulfate was filtered off, the solvent was distilled off under reduced pressure, and the residue was purified with a silica gel column, and dimethylbis (2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl) silane was diluted lightly. 8.6 g (88% yield) of a yellow solid was obtained.

(V) Synthesis of dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl}] hafnium In a 500 ml glass reaction vessel, 8.6 g (13 mmol) of dimethylbis (2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl) silane and 300 ml of diethyl ether were added, and -70 ° C. in a dry ice-methanol bath. Until cooled. Thereto was added dropwise 15 ml (25 mmol) of a 1.66 mol / L n-butyllithium-n-hexane solution, and the mixture was stirred for 3 hours. The solvent of the reaction solution was distilled off under reduced pressure, 400 ml of toluene and 40 ml of diethyl ether were added, and the solution was cooled to −70 ° C. in a dry ice-methanol bath. Thereto was added 4.0 g (13 mmol) of hafnium tetrachloride. Thereafter, the mixture was stirred overnight while gradually returning to room temperature.
The solvent was distilled off under reduced pressure, recrystallized with dichloromethane-hexane, and dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl]. )}] 7.6 g (yield 65%) of a hafnium racemate as yellow crystals was obtained.
The identification value by 1H-NMR about the obtained racemic body is described below.
¹ H-NMR (C ₆ D ₆ ) identification result Racemate: δ 0.95 (s, 6H), δ 1.10 (d, 12H), δ 2.08 (s, 6H), δ 2.67 (m, 2H) , Δ 5.80 (d, 2H), δ 6.37 (d, 2H), δ 6.74 (dd, 2H), δ 7.07 (d, 2H), δ 7.13 (d, 4H), δ 7.28 ( s, 2H), δ 7.30 (d, 2H), δ 7.83 (d, 4H).

<Synthesis of catalyst component [A-2]>
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. It carried out like.

<Synthesis of catalyst component (B)>
(I) Chemical treatment of ion-exchange layered silicate 96% sulfuric acid (668 g) was added to 2,264 g of distilled water in a separable flask, and then montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL: average particle size 19 μm) as a layered silicate. ) 400 g was added. The slurry was heated at 90 ° C. for 210 minutes. When 4,000 g of distilled water was added to the reaction slurry and filtered, 810 g of a cake-like solid was obtained.
Next, 432 g of lithium sulfate and 1,924 g of distilled water were added to the separable flask to make a lithium sulfate aqueous solution, and the entire amount of the cake-like solid was charged. The slurry was reacted at room temperature for 120 minutes. 4 L of distilled water was added to this slurry, followed by filtration, and further washing with distilled water to pH 5-6, followed by filtration to obtain 760 g of a cake-like solid.
The obtained solid was preliminarily dried overnight at 100 ° C. under a nitrogen stream, and then coarse particles of 53 μm or more were removed, followed by drying under reduced pressure at 200 ° C. for 2 hours to obtain 220 g of chemically treated smectite.
The obtained solid was preliminarily dried overnight at 100 ° C. under a nitrogen stream, and then coarse particles having a diameter of 53 μm or more were removed, followed by drying under reduced pressure at 200 ° C. for 2 hours to obtain 220 g of chemically treated smectite.
The composition of this chemically treated smectite is Al: 6.45 wt%, Si: 38.30 wt%, Mg: 0.98 wt%, Fe: 1.88 wt%, Li: 0.16 wt%, Al / Si = 0.175 [mol / mol].

<Preparation of prepolymerization catalyst 1>
i) Catalyst preparation and prepolymerization In a three-necked flask (volume: 1 L), 20 g of the chemically treated smectite obtained in the above catalyst component (B) was added, and heptane (132 mL) was added to form a slurry, which was then triisobutyl. Add aluminum (25 mmol: 68.0 mL of 143 mg / mL concentration of heptane solution) and stir for 1 hour, then wash with heptane until the residual liquid ratio becomes 1/100, and add heptane to a total volume of 100 mL. It was.
In another flask (volume: 200 mL), rac-dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) obtained by synthesis of the catalyst component [A-1] is used. ) -4- (4-i-propylphenyl) indenyl}] hafnium (180 μmol) was dissolved in toluene (42 mL) (Solution 1), and in another flask (volume 200 mL), the above catalyst component [A -2] dissolved in rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium (120 μmol) in toluene (18 mL). (Solution 2).
Triisobutylaluminum (0.84 mmol: 1.2 mL of a heptane solution with a concentration of 143 mg / mL) was added to a 1 L flask containing the chemically treated smectite, and then the above solution 1 was added and stirred at room temperature for 20 minutes. Thereafter, triisobutylaluminum (0.36 mmol: 0.50 mL of a heptane solution having a concentration of 143 mg / mL) was added, and then the above solution 2 was added and stirred at room temperature for 1 hour.
Thereafter, 338 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 the temperature at 40 ° C. for 4 hours. Thereafter, propylene feed was stopped and residual polymerization was carried out for 1 hour. After removing the supernatant of the resulting catalyst slurry by decantation, triisobutylaluminum (6 mmol: 17.0 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 1 hour to obtain 60.0 g of a dry prepolymerized catalyst. The prepolymerization magnification (a value obtained by dividing the amount of the prepolymerized polymer by the amount of the solid catalyst) was 2.00 g / g-catalyst.
Hereinafter, this is referred to as “preliminary polymerization catalyst 1”.

<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.
Hydrogen 6.8NL (0.61 g) and triisobutylaluminum (0.12 mol: 0.47 L of heptane solution with a concentration of 50 g / L) were added thereto, and the internal temperature was raised to 70 ° C. Next, 2.4 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 70 ° C.
After 2 hours, 100 ml of ethanol was injected, purged of unreacted propylene, and the inside of the autoclave was purged with nitrogen to terminate the polymerization.
The obtained polymer was dried at 90 ° C. under a nitrogen stream for 1 hour to obtain 16.9 kg of polymer PP-1. The catalytic activity was 7.0 kg-PP / g-catalyst.

<Granulation>
The 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate (trade name) is used with respect to 100 parts by weight of the polypropylene polymer PP-1 obtained by the above polymerization. : Cyanox 1790, manufactured by Nippon Cytec Industries, Ltd.) 0.05 parts by weight, Tris (2,4-di-t-butylphenyl) phosphite (trade name: IRGAFOS 168, manufactured by BASF Japan Ltd.), 0.10 parts by weight, Poly {6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) Imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino} (trade name: Chimassorb 944, BASF Japan Ltd.) (Company) 0.03 parts by weight and stearamide 0.09 parts by weight were mixed and stirred well, then melt kneaded at 220 ° C. using a twin screw extruder (Technobel KZW25TW-45MG-NH). The extruded strand was cut and pelletized to obtain polypropylene (X1).
The results of analyzing the obtained polypropylene X1 are shown in Table 1. As a result of ¹³ C-NMR measurement, it was confirmed that this polypropylene X1 had long chain branching. Further, the branching index g ′ is 0.88, which is a value smaller than 1, which indicates that this polypropylene X1 has long chain branching.

[Production Example 2: Production of polypropylene (X2)]
<Polymerization>
Except that the amount of hydrogen was 8.2 NL (0.73 g), the polymerization operation was performed in the same manner as in Production Example 1 to obtain 19.9 kg of polymer PP-2. The catalytic activity was 8.3 kg-PP / g-catalyst.
<Granulation>
Using the polymer PP-2 obtained by the above polymerization, granulation was carried out in the same manner as in Production Example 1 to obtain polypropylene X2.
Table 1 shows the result of analyzing the obtained polypropylene X2.

[Production Example 3: Production of polypropylene (X3)]
<Polymerization>
A polymerization operation was performed in the same manner as in Production Example 1 except that the amount of hydrogen was 9.7 NL (0.87 g), to obtain 23.1 kg of polymer PP-3. The catalytic activity was 9.6 kg-PP / g-catalyst.
<Granulation>
Using the polymer PP-3 obtained by the above polymerization, granulation was performed in the same manner as in Production Example 1 to obtain polypropylene X3.
The results of analyzing the obtained polypropylene X3 are shown in Table 1.

2.2. Propylene block copolymer (Y)
Y1 and Y2 obtained in the following Production Examples 4 and 5 were used as a polypropylene block copolymer (Y). Table 2 summarizes the properties.
[Production Example 4: Production of propylene-based block copolymer (Y1)]
1. Production of Solid Catalyst Component A 10 liter autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 2 liters of purified toluene was introduced. To this, 200 g of diethoxymagnesium Mg (OEt) ₂ and 1 liter of titanium tetrachloride were added at room temperature. The temperature was raised to 90 ° C. and 50 ml of n-butyl phthalate was introduced. Thereafter, the temperature was raised to 110 ° C. and the reaction was carried out for 3 hours. The reaction product was thoroughly washed with purified toluene.
Subsequently, the refined toluene was introduce | transduced and the whole liquid quantity was adjusted to 2L. 1 liter of titanium tetrachloride was added at room temperature, the temperature was raised to 110 ° C., and the reaction was carried out for 2 hours. The reaction product was thoroughly washed with purified toluene. Further, using purified n-heptane, toluene was replaced with n-heptane to obtain a slurry of a solid catalyst component.
A portion of this slurry was sampled and dried. As a result of analysis, the titanium content of the solid catalyst component was 2.7% by weight, and the magnesium content was 18% by weight. The average particle size of the solid catalyst component was 33 μm.

Next, a 20 liter autoclave equipped with a stirrer was sufficiently replaced with nitrogen, and 100 g of the solid catalyst component slurry was introduced as a solid catalyst component. Purified n-heptane was introduced to adjust the concentration of the solid catalyst component to 25 g / liter. 50 mL of silicon tetrachloride SiCl ₄ was added and reacted at 90 ° C. for 1 hour. The reaction product was thoroughly washed with purified n-heptane.
Thereafter, purified n-heptane was introduced to adjust the liquid level to 4 liters. Here, 30 ml of dimethyldivinylsilane, 30 ml of t-butylmethyldimethoxysilane (t-C ₄ H ₉ ) (CH ₃ ) Si (OCH ₃ ) _2, and n-heptane diluted solution of triethylaluminum Et ₃ Al are Et _3. 80 g of Al was added and reacted at 40 ° C. for 2 hours. The reaction product was thoroughly washed with purified n-heptane, and a portion of the resulting slurry was sampled and dried. Analysis, in the solid component, titanium _1.2% by weight and contained ₂ 8.8 _{wt% (t-C 4 H 9} ) (CH 3) Si (OCH 3).

Prepolymerization was performed by the following procedure using the solid component obtained above.
Purified n-heptane was introduced into the slurry, and the solid component concentration was adjusted to 20 g / liter. After cooling the slurry to 10 ° C., and 10g added n- heptane dilution of triethylaluminum _Et 3 Al as _Et 3 Al, were added over 4 hours propylene 280 g. After the supply of propylene was completed, the reaction was continued for another 30 minutes.
Next, the gas phase was sufficiently replaced with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was extracted from the autoclave and vacuum dried to obtain a solid catalyst component (catalyst 1). This solid catalyst component (Catalyst 1) contained 2.5 g of polypropylene per 1 g of the solid component. Analysis, in the polypropylene obtained by removing part of the solid catalyst component (catalyst 1), titanium _1.0% by weight, _{2 (t-C 4 H 9)} (CH 3) Si (OCH 3) 8.2 It was included by weight.

2. Production of propylene block copolymer Polymerization was carried out using a continuous reaction apparatus comprising two fluidized bed reactors having an internal volume of 2000 liters.
First, in a first reactor, a polymerization temperature of 65 ° C., a propylene partial pressure of 1.8 MPa (absolute pressure), and hydrogen as a molecular weight control agent are continuously added so that the molar ratio of hydrogen / propylene is 0.015. At the same time, triethylaluminum was supplied at 4.0 g / hr, and the catalyst 1 was supplied so that the polymerization rate of the monomer was 16 kg / hr. The powder polymerized in the first reactor (crystalline propylene polymer) is continuously withdrawn at a rate of 16 kg / hr so that the amount of powder held in the reactor is 40 kg, and continuously into the second reactor. Transferred (first stage polymerization step).

Next, in the second reactor, propylene and ethylene were continuously supplied at a polymerization temperature of 70 ° C. and a monomer pressure of 1.5 MPa so that the molar ratio of ethylene / propylene was 0.29. In addition, hydrogen as a molecular weight control agent is continuously supplied so that the molar ratio of hydrogen / propylene is 0.0008, and ethyl alcohol is 1.17 with respect to triethylaluminum supplied to the first reactor. It supplied so that it might become a double mole.
The powder polymerized in the second reactor is continuously withdrawn into the vessel so that the amount of powder retained in the reactor is 60 kg, and the reaction is stopped by supplying nitrogen gas containing moisture. A polymer was obtained (second stage polymerization step).

  With respect to 100 parts by weight of the resulting propylene / ethylene block copolymer powder, 0.2 parts by weight of “IRGASTAB FS 301 FF” (manufactured by BASF), 1,3,5-tris (2, 6-dimethyl-3-hydroxy-4-tertiarybutylbenzoyl) isocyanate (Songwon, trade name: SONGNOX1790) 0.1 parts by weight, 3,9-bis (2,6-di-tert-butyl-4-) Methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane (manufactured by ADEKA, trade name: ADK STAB PEP-36) 0.05 parts by weight, calcium stearate as neutralizing agent 0.03 weight part was added and it mixed for 5 minutes with the super mixer (made by Kawata Co., Ltd.).

Using the obtained blend, a propylene-based block copolymer (Y1) was obtained by an underwater cut granulation method under the following apparatus and conditions.
・ Twin screw extruder (Technobel KZW25TW-45MG-NH)
・ Aperture 30mm, L / D = 25 (PMS30-25 manufactured by IK Corporation)
・ Screw: Full flight CR2.0, Feed part groove depth 4mm + Dalmage ・ Screw speed: 60rpm
・ Set temperature: hopper sewage cooling, C1-C4 each 220, 200, 200, 200 ° C.
・ Die: Strand die ・ Granulation rate: 200 kg / hr
・ Cooling water temperature: 43 ℃
Screen mesh: BMT140ZZ (obtained from Ishikawa Wire Mesh Co., Ltd., special twill woven)

[Production Example 5: Production of propylene-based block copolymer (Y2)]
1. Of Production Example 4 of the solid catalyst component of the solid catalyst component _{preparation, (t-C 4 H 9} ) (CH 3) Si (OCH 3) instead of _{2, (i-Pr) 2} Si (OCH 3) 2 This was carried out according to Production Example 4 except that was used.

2. Production of propylene-based block copolymer Using the catalyst prepared above, the molar ratio of hydrogen / propylene in the first stage polymerization was 0.016 according to the production procedure of the propylene / ethylene block copolymer of Production Example 4 above. In addition, the first charge of ethyl alcohol was changed so that the hydrogen / propylene molar ratio in the second-stage polymerization was 0.00015, and the molar ratio of propylene and ethylene was 0.26. Propylene / ethylene block copolymer is produced at 1.19 moles relative to triethylaluminum supplied to the reactor, and the same granulation as in Production Example 4 is carried out to produce a propylene-based block copolymer (Y2). Got.

2.3. Polypropylene resin composition This is a blend of polypropylene (X) and propylene-based block copolymer (Y). The results are summarized in Table 3.

[Production Example 6]
Polypropylene X3 and propylene-based block copolymer Y1 are blended at 90:10 (weight ratio) and stirred thoroughly, then melt-kneaded using a single-screw extruder under the following conditions, and the extruded strand is cut with a fan cutter. To obtain a polypropylene resin composition A.
Extruder: Diameter 30 mm, L / D = 25 (IKG PMS30-25)
・ Screw: Full flight CR = 2.0, Feed part groove depth 4mm + Dalmage ・ Screw rotation speed: 60rpm
Set temperature: hopper water cooling, C1 / C2 / C3 / C4 = 220/200/200/200 ° C.
・ Die: 1mm diameter strand die

[Production Example 7]
A polypropylene resin composition B was obtained in the same manner as in Production Example 6 except that the polypropylene X3 and the propylene-based block copolymer Y1 were changed to 70:30 (weight ratio).

[Production Example 8]
A polypropylene resin composition C was obtained in the same manner as in Production Example 6 except that polypropylene X3 and propylene block copolymer Y1 were changed to 10:90 (weight ratio).

[Production Example 9]
A polypropylene resin composition D was obtained in the same manner as in Production Example 7 except that the propylene block copolymer was changed to Y2.

3. Production of unstretched film and counting of the number of gels [Example 1]
Using the polypropylene resin composition A, a film with a thickness of 25 μm was produced with a CF-350 type film molding apparatus manufactured by Create Plastic Co., Ltd., and the number of gels on the film was counted using a CCD defect detector (SCANTEC 7000) manufactured by Nagase Sangyo Co., Ltd. did. The details are shown below.
Polypropylene resin composition in a CR45-25 extruder (caliber 40 mm, L / D = 25) having a full flight metering type screw and a straight manifold type T die (350 type film die) having a width of 350 mm at the tip. Insert A. The setting condition of the extruder was the condition (3) shown in Table 4, and the screw rotation speed was 55 rpm. The molten resin from the T-die was taken out into a non-stretched film by a double chill roll type film take-up machine (CR-400 type) with a cooling roll temperature set to 40 ° C.
The number of gels was counted at the center of the film between the take-up machine and the winder using the above defect detector. The inspection width and inspection length were each 10 mm wide, 5 m long (inspection area 0.05 m ² ), the number of inspections was 600 times, and the average value obtained for each size classification was calculated by converting the unit area. The results are shown in Table 5.

[Example 2]
A film was prepared in the same manner as in Example 1 except that B was used as the polypropylene resin composition, and the number of gels was calculated. The results are shown in Table 5.

[Example 3]
A film was prepared in the same manner as in Example 1 except that C was used as the polypropylene resin composition and the setting condition of the extruder was changed to the condition (2) shown in Table 4, and the number of gels was calculated. The results are shown in Table 5.

[Comparative Example 1]
A film was prepared in the same manner as in Example 1 except that D was used as the polypropylene resin composition, and the number of gels was calculated. The results are shown in Table 5.

[Example 4]
A film was prepared in the same manner as in Example 1 except that polypropylene X1 was used instead of the polypropylene resin composition, and the setting condition of the extruder was changed to the condition (1) shown in Table 4, and the number of gels was calculated. . The results are shown in Table 6.

[Example 5]
A film was produced in the same manner as in Example 1 except that polypropylene X2 was used and the setting condition of the extruder was changed to the condition (2) shown in Table 4, and the number of gels was calculated. The results are shown in Table 6.

[Example 6]
A film was prepared in the same manner as in Example 1 except that polypropylene X3 was used and the setting condition of the extruder was changed to the condition (3) shown in Table 4, and the number of gels was calculated. The results are shown in Table 6.

[Comparative Example 2]
A film was produced in the same manner as in Example 4 except that polypropylene X4 was used. And the like holes in the film is free in the gel due to calculate the number of gels using the value of the largest test area test area of 0.05 m ² could be continuous measurement because it could not be secured (0.015 m ²⁾ . The results are shown in Table 6.

4). Production and evaluation of foam sheet using T-die [Example 7]
100 parts by weight of the polypropylene resin composition A and 0.5 parts by weight of a chemical foaming agent (trade name: Hydrocelol CF40E-J, manufactured by Nippon Boehringer Ingelheim Co., Ltd.) as a foam regulator are stirred and mixed uniformly with a ribbon blender. Was put into a single screw extruder having a barrel hole for injecting a physical foaming agent. Polypropylene resin foamed by injecting and kneading 0.35 parts by weight of liquefied carbon dioxide to 100 parts by weight of the mixture with 100 parts by weight of the mixture while plasticizing by heating and melting at the front stage of the extruder and decomposing the cell regulator. After forming the molding material, the polypropylene resin foam molding material was quickly cooled after the extruder and extruded from a T-die having a width of 750 mm and a lip width of 0.4 mm through a feed block.
At this time, using two single-screw extruders, propylene block copolymer resin (manufactured by Nippon Polypro Co., Ltd., grade name “BC3BRF”, MFR = 12 g / 10 min) was heated and melt extruded to both surfaces. A multilayer foam sheet having two types and three layers composed of a non-foamed layer, a foamed layer, and a non-foamed layer was laminated on the layers. The extruded multilayer foam sheet was first cooled on one side by a roll with a diameter of 80 mm installed in the immediate vicinity of the die, then cooled on both sides with three rolls with a diameter of 100 mm installed thereafter, and taken up at a constant speed by a pinch roll. .
The operating conditions of each extruder are as follows.
・ Extruder (foamed layer)
Diameter: 65 mm, L / D = 50, physical foaming agent inlet: L / D = 20 position Screw rotation speed: 75 rpm
Set temperature: C1 / C2-C4 / C5 / C6 to C9 = 180/240/190/175 ° C.
Discharge rate: Approximately 70kg / h
・ Extruder (non-foamed layer)
Aperture: 40 mm, L / D = 28
Screw rotation speed: 50rpm
Set temperature: C1 / C2 / C3 / C4 = 180/230/190/180 ° C.
-Feed block temperature: 175 ° C
-Die temperature: 175 ° C
・ Cooling roll temperature: 15 ℃
・ Pickup speed: 4.5m / min
The obtained multilayer foamed sheet has a layer configuration in which the thickness ratio of non-foamed layer: foamed layer: non-foamed layer is 4: 92: 4, the density is 0.30 g / cm ³ , and the foamed layer cell diameter is 80 μm. The appearance was good with a dense cell structure with an open cell rate of 8%. Table 7 shows the evaluation results of the foam sheet.

[Example 8]
A foamed sheet was produced in the same manner as in Example 7 except that B was used as the polypropylene resin composition.
The obtained multilayer foamed sheet has a layer configuration in which the thickness ratio of non-foamed layer: foamed layer: non-foamed layer is 4: 92: 4, the density is 0.30 g / cm ³ , the foamed layer has a bubble diameter of 90 μm, The appearance was good with a dense cell structure with an open cell ratio of 5%. Table 7 shows the evaluation results of the foam sheet.

[Example 9]
A foamed sheet was produced in the same manner as in Example 7, except that the polypropylene resin composition was changed to C.
The obtained multilayer foamed sheet has a layer configuration in which the thickness ratio of non-foamed layer: foamed layer: non-foamed layer is 4: 92: 4, the density is 0.31 g / cm ³ , and the foamed layer cell diameter is 120 μm. The appearance was good with a dense cell structure with an open cell rate of 7%. Table 7 shows the evaluation results of the foam sheet.

[Example 10]
A foamed sheet was produced in the same manner as in Example 8 except that the foamed layer was a single layered sheet without coextrusion of the non-foamed layer. The obtained single-layer foamed sheet had a good appearance having a dense cell structure with a density of 0.29 g / cm ³ , a foam layer cell diameter of 120 μm, and an open cell ratio of 14%. Table 7 shows the evaluation results of the foam sheet.

[Comparative Example 3]
A foam sheet was produced in the same manner as in Example 7, except that the polypropylene resin composition was changed to D. The obtained multilayer foamed sheet had a density of 0.37 g / cm ³ , a low foaming ratio, and an open cell ratio of 30%. The appearance of the foam sheet was confirmed to have local irregularities that seem to be caused by the gel in the foam layer. Table 7 shows the evaluation results of the foam sheet.

[Comparative Example 4]
A single-layer foamed sheet was produced in the same manner as in Example 10 except that the polypropylene resin composition was changed to D. The obtained single-layer foamed sheet had a density of 0.41 g / cm ³ , a low expansion ratio, and an open cell ratio of 44%. The appearance of the foam sheet was confirmed on the entire surface, which was thought to be caused by gel in the foam layer. Table 7 shows the evaluation results of the foam sheet.

5. Production and evaluation of foamed sheet using circular die [Example 11]
100 parts by weight of polypropylene X1 and 0.5 parts by weight of a chemical foaming agent (trade name: Hydrocerol CF40E-J, manufactured by Nippon Boehringer Ingelheim Co., Ltd.) as a bubble adjusting agent are stirred and mixed uniformly with a ribbon blender. Were put into tandem type extruders of 40 mm and 50 mm, respectively. The cylinder set temperature of the first stage extruder is set to 230 ° C., and the resin is heated and melted to be plasticized, and 0.99 parts by weight of isobutane is added to 100 parts by weight of the mixture while decomposing the bubble regulator. After a polypropylene resin foam molding material was injected and kneaded with a circular die attached to the tip of the extruder (set temperature 175 ° C., diameter 50 mm) , Gap = 0.75 mm), the polypropylene resin foam molding material was extruded into the atmosphere and foamed. The rotational speed of the first stage extruder was 90 rpm, and the rotational speed of the second stage extruder was 10 rpm.
The foam extruded from the die was passed through a cooling mandrel having a water temperature of 10 ° C. and having an outer diameter of 120 mm to cool the inner surface, and at the same time, air was blown from an air ring attached in the immediate vicinity of the die to cool the outer surface. Thereafter, the sheet was cut by a rotor cutter to form a sheet, the thickness was adjusted at the take-up roll speed, and the sheet was wound by a pinch roll and a take-up roll. The obtained foamed sheet had a density of 0.16 g / cm ³ , a foam layer bubble diameter of 100 μm, an open cell ratio of 10%, little corrugation, and good appearance. Table 8 shows the evaluation results of the obtained foamed sheet.

[Example 12]
A foamed sheet was produced in the same manner as in Example 11 except that the setting temperature of the second stage extruder was set to 180 ° C. for polypropylene X2. The obtained foamed sheet had a density of 0.16 g / cm ³ , a foam layer bubble diameter of 120 μm, an open cell ratio of 7%, little corrugation, and good appearance. Table 8 shows the evaluation results of the obtained foamed sheet.

[Example 13]
A foam sheet is produced in the same manner as in Example 11 except that the injection amount of polypropylene is X3 and the amount of isobutane injected is 0.80 parts by weight with respect to the polypropylene resin foam molding material, and the setting temperature of the second stage extruder is 175 ° C. did. The obtained foamed sheet had a density of 0.20 g / cm ³ , a foam layer bubble diameter of 120 μm, an open cell ratio of 10%, no corrugation, and a good appearance. Table 8 shows the evaluation results of the obtained foamed sheet.

[Comparative Example 5]
A foam sheet was produced in the same manner as in Example 11 except that polypropylene was changed to D. The obtained foam sheet had a density of 0.20 g / cm ³ , a foam layer bubble diameter of 100 μm, an open cell ratio of 10%, and no corrugation occurred, but local irregularities due to gel were observed. Table 8 shows the evaluation results of the obtained foamed sheet.

  By comparing Examples and Comparative Examples, the polypropylene resin for foam molding and the polypropylene resin composition for foam molding according to the present invention have excellent foaming properties, high thermoforming suitability for foamed sheets, and excellent appearance of the resulting container. It is clear.

The polypropylene resin for foam molding and the polypropylene resin composition for foam molding according to the present invention have excellent foaming characteristics, high thermoforming suitability of the foam sheet, and excellent appearance of the resulting container. It can be suitably used for food containers such as cups, vehicle interior materials such as automobile door trims and automobile trunk mats, packaging, stationery, and building materials, and has an extremely high industrial value.

Claims (7)

In the method for producing a polypropylene resin foam molding material by blending 0.05 to 6.0 parts by weight of a foaming agent with respect to 100 parts by weight of the resin composition,
As the resin composition,
10 to 99% by weight of polypropylene (X) produced by macromer copolymerization using a combination of metallocene catalysts and 1 to 90% by weight of propylene-based block copolymer (Y) produced by sequential polymerization,
Polypropylene (X) satisfies the following characteristics (Xi) to (X-iv),
Characteristic (Xi): Long chain branching.
Characteristic (X-ii): Melt tension (MT) measured at 230 ° C. is 3 to 25 g.
Characteristic (X-iii): Melt flow rate (MFR) exceeds 0.9 g / 10 min,
15 g / 10 min or less.
Characteristic (X-iv): 25 ° C. xylene soluble component amount (CXS) is polypropylene (X)
It is less than 5 wt% with respect to the total amount.
The propylene-based block copolymer (Y) may contain 10% by weight or less of a comonomer. The propylene (co) polymer (Y-1) and the ethylene content are 11.0 to 38.0% by weight.
When the total amount of the propylene-based block copolymer (Y) is 100% by weight, (Y-1) is 50 to 99% by weight, (Y-
2) is 1 to 50% by weight, and the MFR range of the propylene-based block copolymer (Y) is in the range of 2.1 to 170 g / 10 min.
The melt tension (MT) measured at 230 ° C. is 1 g or more,
A method comprising selecting a resin composition in which the number of gels having a major axis of 0.5 mm or more is 50 / m ² or less when an unstretched film having a thickness of 25 μm is used.   A polypropylene resin foam molded article obtained by extruding a foam molding material obtained by the production method according to claim 1.   A polypropylene resin laminate foam molded article obtained by coextrusion of the polypropylene resin foam molded article according to claim 2 and a non-foamed layer made of a thermoplastic resin composition.   The polypropylene resin laminate foam molded article according to claim 3, wherein the thermoplastic resin composition contains 50 parts by weight or less of an inorganic filler with respect to 100 parts by weight of the thermoplastic resin.   A molded article obtained by thermoforming the polypropylene resin foam molded article or laminated foam molded article according to any one of claims 2 to 4.   A molded product obtained by subjecting the foam molding material obtained by the production method according to claim 1 to any one of injection molding, thermoforming, blow molding or bead foam molding. It is a sheet form, The molded object as described in any one of Claims 2-4.

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