JP7328745B2 - Expandable polypropylene composition, injection foam molded article, and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an expandable polypropylene composition, an injection foam molded article, and a method for producing the same.

Polypropylene resin compositions are widely used in various industrial products due to their excellent properties. In particular, the injection foam molded product is useful as automobile interior parts, housings for electrical and electronic products, toys, daily necessities, miscellaneous goods, building material parts, packaging materials, etc. Such molded products have a light weight and a good surface appearance. are required to be good. In order to satisfy these properties, Patent Document 1 discloses a polypropylene component (A) containing at least a crystalline propylene/ethylene copolymer (77% by mass or more and 95% by mass or less) and an ethylene/1-octene random copolymer (B). A resin component containing 5% by mass or more and 13% by mass or less and 0% by mass or more and 10% by mass or less of an ethylene/1-butene random copolymer (C), and 0.1 part by mass or more per 100 parts by mass of the resin component It has been proposed to use a foamable resin composition containing 5 parts by mass or less of a foaming agent (D) and carry out injection foam molding by combining the counterpressure method and the core-back method. Further, in Patent Document 2, a linear propylene/ethylene block copolymer and a propylene-based polymer having specific MFR values, die swell ratios, elongational viscosities, and ratios of the first normal stress difference and the shear stress A polypropylene resin, a specific polymerization method, MFR, melting peak temperature, Mw / Mn, a propylene-ethylene block copolymer having a tan δ curve peak at 0 ° C. or less, an ethylene elastomer, and a foaming agent Injection foam molding using a polypropylene resin composition has been proposed. However, in the foamable resin composition used in such a method, it was necessary to previously melt-knead all components except for the foaming agent. Therefore, there are restrictions due to facilities, processes, personnel availability, raw material availability, etc., and there is a problem that it is not practical in fields that require systematic, stable low-cost, mass production. In Patent Document 3, a specific polypropylene resin having a long-chain branched structure and two types of specific propylene-ethylene block copolymers are combined in a specific proportion to form a polypropylene-based resin composition and a dry blend of a blowing agent. A method to do so is proposed. However, it is necessary to secure facilities and processes involved in the production of components having long-chain branched structures, and there are problems such as difficulty in obtaining raw materials.

Patent No. 3990236 JP 2012-1655 A JP 2014-141566 A

An object of the present invention is to provide an expandable polypropylene composition which gives an injection foamed article having excellent handleability and good appearance.

The above problems are solved by the present invention described below.
[1] 50 to 99 parts by weight of block polypropylene containing 5% by weight or more of ethylene as component (A1);
As component (B), 1 to 50 parts by weight of a masterbatch composition containing
Component (B1): a propylene (co)polymer containing 0-3% by weight of ethylene or one or more C4-C10-α-olefin-derived units, and Component (B2): 25-35% by weight of ethylene-derived units. and a foamable polypropylene composition comprising, as component (C), a blowing agent,
Requirements for:
1) MFR (230° C., load 2.16 kg) of component (A1) is 5 to 100 g/10 min;
2) The intrinsic viscosity of the component (A1) soluble in xylene is 0.5 to 5.9 dl/g.
3) MFR (230° C., load 2.16 kg) of component (B) is 5 to 30 g/10 min;
4) Mw of the xylene-insoluble portion of component (B) measured by GPC is 10×10 ⁴ to 30×10 ⁴ and Mw/Mn is 6 to 20.
5) The intrinsic viscosity of the component (B) soluble in xylene is 6.0 to 9.0 dl/g.
6) MFR (230 ° C., load 2.16 kg) of the composition excluding the component (C) from the expandable polypropylene composition is 5 to 100 g / 10 minutes.
7) the weight ratio of component (B1):component (B2) is 65-85:15-35;
An expandable polypropylene composition that satisfies
[2] The component (B) is
(i) a solid catalyst containing as an essential component an electron donor compound selected from magnesium, titanium, halogen, and succinate compounds;
The expandable polypropylene composition according to [1], which is a masterbatch composition obtained by polymerizing a monomer using a catalyst containing (ii) an organoaluminum compound; and (iii) an external electron donor compound.
[3] The composition according to [1] or [2], wherein the composition excluding the component (C) from the expandable polypropylene composition has an MFR (230° C., load 2.16 kg) of 10 to 70 g/10 min. An expandable polypropylene composition.
[4] The expandable polypropylene composition according to any one of [1] to [3], wherein the content of component (B) is 2 to 30 parts by weight.
[5] The expandable polypropylene composition according to [4], wherein the content of component (B) is 5 to 25 parts by weight.
[6] The expandable polypropylene composition according to any one of [1] to [5], containing 40 parts by weight or less of homopolypropylene (A2) with respect to the total of 100 parts by weight of components (A1) and (B). thing.
[7] The expandable polypropylene according to any one of [1] to [6], containing 40 parts by weight or less of additional elastomer (A3) with respect to a total of 100 parts by weight of components (A1) and (B). Composition.
[8] The expandable polypropylene composition according to any one of [1] to [7], which contains a filler (A4) of 40 parts by weight or less with respect to a total of 100 parts by weight of the components (A1) and (B). thing.
[9] Any one of [1] to [8], wherein the component (C) contains 0.1 to 5 parts by weight of a foaming agent with respect to a total of 100 parts by weight of the components (A1) and (B). An expandable polypropylene composition as described.
[10] An injection foam molded article comprising an injection step of injecting the expandable polypropylene composition according to any one of [1] to [9] into a cavity, and a foaming step of expanding the expandable polypropylene composition. manufacturing method.
[11] The expandable polypropylene composition is prepared and foamed without previously melt-kneading the components (A1) and (B), and optionally components (A2), (A3), and (A4). The method for producing an injection foam molded article according to [10], comprising the steps of:
[12] An injection foam molded article obtained by injection molding the expandable polypropylene composition according to any one of [1] to [9].

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an expandable polypropylene composition which gives an injection foamed article having excellent handleability and good appearance.

The present invention will be described in detail below. In the present invention, "X to Y" includes X and Y which are the end values.

1. Expandable polypropylene composition The expandable polypropylene composition of the present invention (hereinafter also simply referred to as "the composition of the present invention") is an impact-resistant polypropylene polymer component ( A), component (B) which is a masterbatch composition, and component (C) which is a foaming agent are included as essential components. Since the composition of the present invention uses a masterbatch composition, it is not necessary to previously melt-knead all the components except for the foaming agent, so that it is excellent in handleability and workability during molding. The MFR of the composition excluding the component (C) from the expandable polypropylene composition of the present invention, that is, the composition consisting of the component (A) and the component (B) is 5 to 100 g/10 at 230 ° C. and a load of 2.16 kg. minutes, preferably 10 to 70 g/10 minutes. When component (C) is included, it foams during the MFR measurement and it is not realistic to measure it accurately. Therefore, the MFR of the composition is generally evaluated with the composition excluding the foaming agent. . When the MFR value exceeds the upper limit, the foam tends to break during foam molding, and the appearance of the molded product after foam molding tends to be poor. Further, when the MFR value is less than the lower limit, the flowability is lowered, so that the processability of the expandable polypropylene composition is lowered.

1-1. Block polypropylene (component (A1))
The expandable polypropylene composition of the present invention contains an impact resistant polypropylene polymer defined in JIS K6921-1 as component (A). Block polypropylene (component (A1)) is one aspect of the impact resistant polypropylene polymer and is an essential component of component (A). Block polypropylenes include polymerized mixtures (also called HECO) obtained by polymerizing ethylene and one or more C3-C10-alpha olefins in the presence of propylene polymers. The block polypropylene of the present invention contains 5% or more by weight of ethylene-derived units. A block polypropylene containing 5% by weight of ethylene-derived units is a copolymer in which the weight ratio of ethylene-derived units to propylene-derived units is 5:95. The same applies to other copolymers. Although the upper limit of the ethylene-derived units is not limited, it is preferably 25% by weight or less. The masterbatch composition, which will be described later, is also a type of HECO, and due to the similarity of the polymer structure, it has the property of being uniformly mixed with the block polypropylene. However, it differs in composition from the block polypropylene.

1-2. Optional components In the composition of the present invention, as optional components of component (A), homopolypropylene (component (A2)), additional elastomer (component (A3)), filler (component (A4)), or a combination thereof may include

1) homopolypropylene (component (A2))
The composition of the present invention may contain, as an optional component (A), 40 parts by weight or less of homopolypropylene per 100 parts by weight of the components (A1) and (B) combined. A foamed molded article containing homopolypropylene has excellent rigidity. The upper limit of the homopolypropylene content is preferably 40 parts by weight or less, and the lower limit is preferably 1 part by weight or more. The homopolypropylene may contain from 0 to 2% by weight of ethylene-derived units.

2) Additional elastomer (component (A3))
The composition of the present invention may contain 40 parts by weight or less of an additional elastomer as an optional component of component (A) per 100 parts by weight of components (A1) and (B) combined. The added elastomer is a polymer having elasticity, and is added mainly for the purpose of improving the impact resistance of the material. The additional elastomer used in the present invention includes a copolymer of ethylene and α-olefin. Examples of α-olefins include α-olefins having 3 to 12 carbon atoms, and specific examples include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and the like. The add-on elastomer preferably has a lower density than the polymers of components (B1) and (B2). For example, although the density of the added elastomer is not limited, it is preferably 0.850 to 0.890 g/cm ³ , more preferably 0.860 to 0.880 g/cm ³ . Such additional elastomers can be prepared, for example, by polymerizing monomers using a homogeneous catalyst such as metallocene or half-metallocene, as described in JP-A-2015-113363. The MFR of the added elastomer is preferably 0.1 to 50 g/10 minutes at 190° C. and a load of 2.16 kg. The upper limit of the content of the added elastomer is preferably 40 parts by weight or less, more preferably 20 parts by weight or less, and even more preferably 15 parts by weight or less. The lower limit is preferably 1 part by weight or more, more preferably 2% by weight or more, and even more preferably 5 parts by weight or more.

3) Filler (component (A4))
The composition of the present invention may contain, as an optional ingredient of component (A), 40 parts by weight or less of a filler per 100 parts by weight of components (A1) and (B) combined. Fillers are added mainly for the purpose of improving the rigidity of materials, such as natural silicic acid or silicates such as talc, kaolinite, calcined clay, virophyllite, selinite, wollastonite; precipitated calcium carbonate, heavy carbonate; carbonates such as calcium and magnesium carbonate; hydroxides such as aluminum hydroxide and magnesium hydroxide; oxides such as zinc oxide and magnesium oxide; powdery fillers such as silicates; flake fillers such as mica; basic magnesium sulfate whiskers, calcium titanate whiskers, aluminum borate whiskers, sepiolite, PMF (Processed Mineral Filler), xonotlite, potassium titanate, and elestadite and balloon-like fillers such as glass balloons and fly ash balloons; inorganic fillers such as glass fibers; and organic fillers such as carbon fibers and cellulose fibers. In order to improve the dispersibility of these fillers, if necessary, the surface treatment of the fillers and the compositing of the fillers and resin (production of a filler masterbatch using polyolefin as a carrier) are performed. good too. At this time, the carrier contained in the masterbatch corresponds to another component described later. Among the fillers, plate-like fillers such as talc are preferable because they have good dispersibility as a component in the composition of the present invention, tend to improve the rigidity of the molded article, and are easily available. The plate-like inorganic filler preferably has an average particle size of 1 to 10 μm, more preferably 3 to 7 μm. The average particle size is measured according to JIS Z8825. A filler may be used individually by 1 type, and may use 2 or more types together.

1-3. Masterbatch composition (component (B))
The masterbatch composition contains the following ingredients.
Component (B1): a propylene (co)polymer containing 0-3% by weight of ethylene or one or more C4-C10-α-olefin-derived units, and Component (B2): 25-35% by weight of ethylene-derived units. Propylene-ethylene copolymer containing

(1) Component (B1): Propylene (co)polymer The propylene (co)polymer is a propylene homopolymer, or more than 0% by weight but not more than 3% by weight of ethylene or C4-C10-α-olefin (hereinafter (also called "comonomer") and propylene. Propylene homopolymer is preferred when rigidity and heat resistance are required in the final product. On the other hand, copolymers are preferred when flexibility and impact resistance are required. The upper limit of the content of comonomer-derived units is 3% by weight or less, preferably 2.8% by weight or less, and more preferably 2.5% by weight or less. If the amount exceeds the upper limit, the stiffness will decrease. Moreover, when the amount is 5.0% by weight or more, the production of the polymer becomes difficult. Although there is no lower limit for the presence of comonomer-derived units, it is preferably 0.5% by weight or more, more preferably 1.0% by weight or more. As the comonomer, ethylene or C4-C8-α-olefins are preferred, and ethylene is more preferred, in terms of availability and the like.

(2) Component (B2): Propylene-Ethylene Copolymer The propylene-ethylene copolymer used in the present invention contains 25 to 35% by weight of ethylene-derived units. If the content of the ethylene-derived units exceeds this range, the affinity between the component (B1) and the component (B2) in the masterbatch composition is impaired, and the foam tends to break during foam molding. Decrease in physical appearance. From this point of view, the upper limit of the content of ethylene-derived units is preferably 33% by weight or less. The lower limit of the content is preferably 27% by weight or more.

(3) Composition ratio The weight ratio of component (B1) to component (B2) is 65-85:15-35. If the amount of component (B2) exceeds this upper limit, production becomes difficult, and if it is less than the lower limit, the effect of improving the external appearance of a foam molded article is reduced. From this point of view, the ratio is preferably 65-75:25-35, more preferably 67-73:27-33.

(4) Characteristics 1) MFR
The MFR of the masterbatch composition at 230° C. and a load of 2.16 kg is 5 to 30 g/10 minutes. When the MFR is within this range, excellent fluidity can be imparted to the expandable polypropylene composition. However, if the value of MFR exceeds the upper limit, the foam tends to break during foam molding, and the appearance of the molded product after foam molding tends to be poor. Further, when the MFR value is less than the lower limit, the flowability is lowered, so that the processability of the expandable polypropylene composition is lowered. In addition, it has poor dispersibility with the component (A1), and may adversely affect the appearance of the foam molded product. From this point of view, the MFR is preferably 5-15 g/10 min, more preferably 7-12 g/10 min.

2) Mw and Mw/Mn of XI
The Mw/Mn measured by GPC of the xylene insolubles (XI) of the masterbatch composition is 6-20. Xylene insolubles are the crystalline component in the composition. Mw is preferably in a relatively low range of 10×10 ⁴ to 30×10 ⁴ . When the molecular weight is low and Mw/Mn, which is an index of the molecular weight distribution, is in a wide range of 6 to 20, the melt tension and extensional viscosity are improved by the high-molecular-weight component, and the fluidity is improved by the low-molecular-weight component. achieved. As a result, a foam-molded article with good appearance can be obtained which is resistant to foam breakage during foam-molding. From this point of view, the Mw is preferably 12×10 ⁴ to 28×10 ⁴ . The Mw/Mn is preferably 7-20, more preferably 8-20, and even more preferably 9-20. Mw and Mw/Mn of XI are determined by obtaining a component insoluble in xylene at 25° C. and measuring the component by GPC (gel permeation chromatography).

3) XSIV
The intrinsic viscosity (XSIV) of the xylene solubles (XS) of the masterbatch composition is also an indicator of the molecular weight of the non-crystalline components in the composition. XSIV is obtained by obtaining a component soluble in xylene at 25° C. and measuring the intrinsic viscosity of the component by a conventional method. In the present invention, XSIV is 6.0-9.0 dl/g. When XSIV is within this range, the melt tension and elongational viscosity are increased, and the appearance of the foam molded product can be improved. From this point of view, the intrinsic viscosity is preferably 6.0 to 8.0 dl/g.

(5) Production method The masterbatch composition may be produced by any method, but the raw material monomer for component (B1) and the raw material monomer for component (B2) are mixed with (i) magnesium, titanium, halogen, and internal electron donors. It is preferably obtained by a method comprising the step of polymerizing using a solid catalyst containing a succinate-based compound as a body, (ii) an organoaluminum compound, and (iii) an external electron donor compound.

1) Solid catalyst (component i)
Component (i) can be prepared by known methods such as contacting a magnesium compound, a titanium compound and an electron donor compound with each other.

A tetravalent titanium compound represented by the general formula: Ti(OR) _g X _4-g is suitable as the titanium compound used for preparing component (i). In the formula, R is a hydrocarbon group, X is a halogen, and 0≤g≤4. Titanium _compounds , _{more specifically titanium} tetrahalides such as _{TiCl 4} , TiBr _{4 and} TiI _{4 ; 9} ) trihalogenated alkoxy _titanium such _{as Cl3} , Ti( _OC2H5 ) _Br3 , Ti( _OisoC4H9 ) _Br3 ; Ti( _{OCH3 ) 2Cl2 ,} Ti( _OC2H5 ) _{2Cl 2} , Ti(O _n -C ₄ H ₉ ) ₂ Cl ₂ , Ti(OC ₂ H ₅ ) ₂ Br ₂ ; Ti(OCH ₃ ) ₃ Cl, Ti(OC ₂ H ₅ ) ₃ Cl , Ti(O _n -C ₄ H ₉ ) ₃ Cl, Ti(OC ₂ H ₅ ) ₃ Br; Ti(OCH ₃ ) ₄ , Ti(OC ₂ H ₅ ) ₄ , Ti( and tetraalkoxytitanium such as O _n -C ₄ H ₉ ) ₄ . Preferred among these are halogen-containing titanium compounds, particularly titanium tetrahalides, and more particularly preferred is titanium tetrachloride.

Magnesium compounds used for the preparation of component (i) include magnesium compounds having a magnesium-carbon bond or magnesium-hydrogen bond, such as dimethylmagnesium, diethylmagnesium, dipropylmagnesium, dibutylmagnesium, diamylmagnesium, dihexylmagnesium, di Decylmagnesium, ethylmagnesium chloride, propylmagnesium chloride, butylmagnesium chloride, hexylmagnesium chloride, amylmagnesium chloride, butylethoxymagnesium, ethylbutylmagnesium, butylmagnesium hydride and the like. These magnesium compounds can be used, for example, in the form of complex compounds with organoaluminum or the like, and may be liquid or solid. Further suitable magnesium compounds include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride; magnesium methoxy chloride, magnesium ethoxy chloride, magnesium isopropoxy chloride, magnesium butoxy chloride, magnesium octoxy chloride; alkoxy magnesium halides; aryloxy magnesium halides such as phenoxy magnesium chloride, methylphenoxy magnesium chloride; alkoxy magnesium halides such as ethoxy magnesium, isopropoxy magnesium, butoxy magnesium, n-octoxy magnesium, 2-ethylhexoxy magnesium; magnesium, allyloxymagnesium such as dimethylphenoxymagnesium; and magnesium carboxylates such as magnesium laurate and magnesium stearate.

Electron donor compounds used in the preparation of component (i) are commonly referred to as "internal electron donors". In the present invention, it is preferred to use an internal electron donor that gives a broad molecular weight distribution. Generally, it is known that the molecular weight distribution can be widened by carrying out polymerization in multiple stages, but when the molecular weight of XI is low, it is difficult to widen the molecular weight distribution. However, by using a specific internal electron donor, it is possible to widen the molecular weight distribution even when the molecular weight of XI is low. The composition polymerized using the catalyst is a composition having the same molecular weight distribution obtained by pellet or powder blending the polymer polymerized using another catalyst, and a composition having the same molecular weight distribution obtained by further multistage polymerization. It exhibits excellent fluidity and large melt tension and elongational viscosity compared to others. This is because, in the composition produced using the catalyst, the high-molecular-weight component and the low-molecular-weight component are united in a state close to the molecular level, but the latter resin composition is not mixed in a state close to the molecular level. This is thought to be due to the fact that they only show the same molecular weight distribution apparently. However, it is not realistic to verbalize this in the claims. Preferred internal electron donors are described below.

Preferred internal electron donors in the present invention are succinate compounds. In the present invention, the succinate compound refers to diesters of succinic acid or substituted succinic acid diesters. The succinate compound will be described in detail below. A succinate compound preferably used in the present invention is represented by the following formula (I).

wherein the groups R ₁ and R ₂ are the same or different from each other and optionally containing heteroatoms, C ₁ -C ₂₀ linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkyl is an aryl group; the groups R ₃ to R ₆ are the same or different from each other and are hydrogen or C ₁ to C ₂₀ linear or branched alkyl, alkenyl, cycloalkyl, aryl, optionally containing heteroatoms; The groups R ₃ -R ₆ which are arylalkyl or alkylaryl groups and which are attached to the same or different carbon atoms may be joined together to form a ring.

R ₁ and R ₂ are preferably C ₁ -C ₈ alkyl, cycloalkyl, aryl, arylalkyl and alkylaryl groups. Particular preference is given to compounds in which R ₁ and R ₂ are selected from primary alkyl, especially branched primary alkyl. Examples of suitable R ₁ and R ₂ groups are C ₁ -C ₈ alkyl groups, eg methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, 2-ethylhexyl. Ethyl, isobutyl and neopentyl are particularly preferred.

One preferred group of compounds represented by formula (I) is a branched alkyl, cycloalkyl, aryl, arylalkyl, wherein R ₃ -R ₅ are hydrogen and R ₆ has 3-10 carbon atoms. , and alkylaryl groups. Preferred specific examples of such monosubstituted succinate compounds are diethyl-sec-butylsuccinate, diethylthexylsuccinate, diethylcyclopropylsuccinate, diethylnorbonylsuccinate, diethylperhydrosuccinate, diethyl Trimethylsilyl succinate, diethyl methoxy succinate, diethyl-p-methoxyphenyl succinate, diethyl-p-chlorophenyl succinate, diethyl phenyl succinate, diethyl cyclohexyl succinate, diethyl benzyl succinate, diethyl cyclohexyl Methyl succinate, diethyl-t-butyl succinate, diethyl isobutyl succinate, diethyl isopropyl succinate, diethyl neopentyl succinate, diethyl isopentyl succinate, diethyl (1-trifluoromethylethyl) succinate , diethylfluorenylsuccinate, 1-ethoxycarbodiisobutylphenylsuccinate, diisobutyl-sec-butylsuccinate, diisobutylthexylsuccinate, diisobutylcyclopropylsuccinate, diisobutylnorbonylsuccinate, diisobutylperihydro Succinate, diisobutyltrimethylsilylsuccinate, diisobutylmethoxysuccinate, diisobutyl-p-methoxyphenylsuccinate, diisobutyl-p-chlorophenylsuccinate, diisobutylcyclohexylsuccinate, diisobutylbenzylsuccinate, diisobutylcyclohexylmethyl succinate, diisobutyl-t-butyl succinate, diisobutyl isobutyl succinate, diisobutyl isopropyl succinate, diisobutyl neopentyl succinate, diisobutyl isopentyl succinate, diisobutyl (1-trifluoromethylethyl) succinate, diisobutyl fluorenyl succinate, dineopentyl-sec-butyl succinate, dineopentyl thexyl succinate, dineopentyl cyclopropyl succinate, dineopentyl norbornyl succinate, dineopentyl perhydrosuccinate , dineopentyltrimethylsilylsuccinate, dineopentylmethoxysuccinate, dineopentyl-p-methoxyphenylsuccinate, dineopentyl-p-chlorophenylsuccinate, dineopentylphenylsuccinate, dineopentylcyclohexylsuccinate dineopentyl benzyl succinate, dineopentyl cyclohexyl methyl succinate, dineopentyl-t-butyl succinate, dineopentyl isobutyl succinate, dineopentyl isopropyl succinate, dineopentyl neopentyls succinate, dineopentyl isopentyl succinate, dineopentyl (1-trifluoromethylethyl) succinate, and dineopentyl fluorenyl succinate.

Another preferred group of compounds within formula (I) are _{C 1} -C _{20 linear} or a branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, or alkylaryl group. Particular preference is given to compounds in which two radicals different from hydrogen are attached to the same carbon atom. Specifically, it is a compound in which R ₃ and R ₄ are groups different from hydrogen, and R ₅ and R ₆ are hydrogen atoms. Preferred examples of such disubstituted succinates are diethyl-2,2-dimethylsuccinate, diethyl-2-ethyl-2-methylsuccinate, diethyl-2-benzyl-2-isopropylsuccinate, diethyl -2-cyclohexylmethyl-2-isobutylsuccinate, diethyl-2-cyclopentyl-2-n-butylsuccinate, diethyl-2,2-diisobutylsuccinate, diethyl-2-cyclohexyl-2-ethylsuccinate diethyl-2-isopropyl-2-methylsuccinate, diethyl-2-tetradecyl-2-ethylsuccinate, diethyl-2-isobutyl-2-ethylsuccinate, diethyl-2-(1-trifluoro methyl ethyl)-2-methylsuccinate, diethyl-2-isopentyl-2-isobutylsuccinate, diethyl-2-phenyl-2-n-butylsuccinate, diisobutyl-2,2-dimethylsuccinate, diisobutyl-2-ethyl-2-methylsuccinate, diisobutyl-2-benzyl-2-isopropylsuccinate, diisobutyl-2-cyclohexylmethyl-2-isobutylsuccinate, diisobutyl-2-cyclopentyl-2-n- Butyl succinate, diisobutyl-2,2-diisobutylsuccinate, diisobutyl-2-cyclohexyl-2-ethylsuccinate, diisobutyl-2-isopropyl-2-methylsuccinate, diisobutyl-2-tetradecyl-2- Ethyl succinate, diisobutyl-2-isobutyl-2-ethylsuccinate, diisobutyl-2-(1-trifluoromethylethyl)-2-methylsuccinate, diisobutyl-2-isopentyl-2-isobutylsuccinate , Diisobutyl-2-phenyl-2-n-butylsuccinate, Dineopentyl-2,2-dimethylsuccinate, Dineopentyl-2-ethyl-2-methylsuccinate, Dineopentyl-2-benzyl-2-isopropyls Succinate, Dineopentyl-2-cyclohexylmethyl-2-isobutylsuccinate, Dineopentyl-2-cyclopentyl-2-n-butylsuccinate, Dineopentyl-2,2-diisobutylsuccinate, Dineopentyl-2-cyclohexyl-2 - ethylsuccinate, dineopentyl-2-isopropyl-2-methylsuccinate, dineopentyl-2-tetradecyl-2-ethylsuccinate, dineopentyl-2-isobutyl-2-ethylsuccinate, dineopentyl-2-( 1-trifluoromethylethyl)-2-methylsuccinate, dineopentyl-2-isopentyl-2-isobutylsuccinate, and dineopentyl-2-phenyl-2-n-butylsuccinate.

Furthermore, compounds in which at least two groups different from hydrogen are attached to different carbon atoms are also particularly preferred. Specifically, it is a compound in which R ₃ and R ₅ are groups different from hydrogen. In this case, R ₄ and R ₆ may be a hydrogen atom or a group different from hydrogen, but one of them is preferably a hydrogen atom (trisubstituted succinate). Preferred specific examples of such compounds are diethyl-2,3-bis(trimethylsilyl)succinate, diethyl-2,2-sec-butyl-3-methylsuccinate, diethyl-2-(3,3,3- trifluoropropyl)-3-methylsuccinate, diethyl-2,3-bis(2-ethylbutyl)succinate, diethyl-2,3-diethyl-2-isopropylsuccinate, diethyl-2,3-diisopropyl-2 -methylsuccinate, diethyl-2,3-dicyclohexyl-2-methyldiethyl-2,3-dibenzylsuccinate, diethyl-2,3-diisopropylsuccinate, diethyl-2,3-bis(cyclohexylmethyl ) succinate, diethyl-2,3-di-t-butylsuccinate, diethyl-2,3-diisobutylsuccinate, diethyl-2,3-dineopentylsuccinate, diethyl-2,3-diiso Pentylsuccinate, diethyl-2,3-(1-trifluoromethylethyl)succinate, diethyl-2,3-tetradecylsuccinate, diethyl-2,3-fluorenylsuccinate, diethyl-2-isopropyl -3-isobutylsuccinate, diethyl-2-tert-butyl-3-isopropylsuccinate, diethyl-2-isopropyl-3-cyclohexylsuccinate, diethyl-2-isopentyl-3-cyclohexylsuccinate, diethyl -2-tetradecyl-3-cyclohexylmethylsuccinate, diethyl-2-cyclohexyl-3-cyclopentylsuccinate, diisobutyl-2,3-diethyl-2-isopropylsuccinate, diisobutyl-2,3-diisopropyl-2 -methylsuccinate, diisobutyl-2,3-dicyclohexyl-2-methylsuccinate, diisobutyl-2,3-dibenzylsuccinate, diisobutyl-2,3-diisopropylsuccinate, diisobutyl-2,3- bis(cyclohexylmethyl)succinate, diisobutyl-2,3-di-t-butylsuccinate, diisobutyl-2,3-diisobutylsuccinate, diisobutyl-2,3-dineopentylsuccinate, diisobutyl-2, 3-diisopentylsuccinate, diisobutyl-2,3-(1-trifluoromethylethyl)succinate, diisobutyl-2,3-tetradecylsuccinate, diisobutyl-2,3-fluorenylsuccinate, diisobutyl -2-isopropyl-3-isobutylsuccinate, diisobutyl-2-tert-butyl-3-isopropylsuccinate, diisobutyl-2-isopropyl-3-cyclohexylsuccinate, diisobutyl-2-isopentyl-3-cyclohexyls succinate, diisobutyl-2-tetradecyl-3-cyclohexylmethylsuccinate, diisobutyl-2-cyclohexyl-3-cyclopentylsuccinate, dineopentyl-2,3-bis(trimethylsilyl)succinate, dineopentyl-2,2-sec- Butyl-3-methylsuccinate, Dineopentyl-2-(3,3,3-trifluoropropyl)-3-methylsuccinate, Dineopentyl-2,3-bis(2-ethylbutyl)succinate, Dineopentyl-2, 3-Diethyl-2-isopropylsuccinate, Dineopentyl-2,3-diisopropyl-2-methylsuccinate, Dineopentyl-2,3-dicyclohexyl-2-methylsuccinate, Dineopentyl-2,3-dibenzyls Succinate, Dineopentyl-2,3-diisopropylsuccinate, Dineopentyl-2,3-bis(cyclohexylmethyl)succinate, Dineopentyl-2,3-di-t-butylsuccinate, Dineopentyl-2,3-diisobutyls Succinate, Dineopentyl-2,3-dineopentyl succinate, Dineopentyl-2,3-diisopentyl succinate, Dineopentyl-2,3-(1-trifluoromethylethyl)succinate, Dineopentyl-2,3 -tetradecylsuccinate, dineopentyl-2,3-fluorenylsuccinate, dineopentyl-2-isopropyl-3-isobutylsuccinate, dineopentyl-2-tert-butyl-3-isopropylsuccinate, dineopentyl-2 - isopropyl-3-cyclohexylsuccinate, dineopentyl-2-isopentyl-3-cyclohexylsuccinate, dineopentyl-2-tetradecyl-3-cyclohexylmethylsuccinate, dineopentyl-2-cyclohexyl-3-cyclopentylsuccinate be.

Among the compounds of formula (I), compounds in which some of the groups R ₃ to R ₆ are joined together to form a ring can also preferably be used. Compounds listed in JP-A-2002-542347 as such compounds, for example, 1-(ethoxycarbonyl)-1-(ethoxyacetyl)-2,6-dimethylcyclohexane, 1-(ethoxycarbonyl)-1-( ethoxyacetyl)-2,5-dimethylcyclopentane, 1-(ethoxycarbonyl)-1-(ethoxyacetylmethyl)-2-methylcyclohexane, 1-(ethoxycarbonyl)-1-(ethoxy(cyclohexyl)acetyl)cyclohexane can be mentioned. In addition, cyclic succinate compounds such as diisobutyl 3,6-dimethylcyclohexane-1,2-dicarboxylate and diisobutyl cyclohexane-1,2-dicarboxylate disclosed in WO 2009/069483 are also suitable. can be used for As examples of other cyclic succinate compounds, compounds disclosed in WO 2009/057747 are also preferred.

In compounds of formula (I), when the groups R ₃ to R ₆ contain heteroatoms, the heteroatoms may be Group 15 atoms, including nitrogen and phosphorus atoms, or Group 16 atoms, including oxygen and sulfur atoms. preferable. Compounds in which groups R ₃ to R ₆ contain group 15 atoms include compounds disclosed in JP-A-2005-306910. On the other hand, compounds in which groups R ₃ to R ₆ contain Group 16 atoms include compounds disclosed in JP-A-2004-131537.

In addition, an internal electron donor that gives the same molecular weight distribution as the succinate compound may be used. Examples of such internal electron donors include diphenyldicarboxylic acid esters described in JP-A-2013-28704, cyclohexene dicarboxylic acid esters described in JP-A-2014-201602, and JP-A-2013-28705. dicycloalkyldicarboxylic acid esters, diol dibenzoate described in Japanese Patent No. 4959920, and 1,2-phenylene dibenzoate described in International Publication No. 2010/078494.

2) organoaluminum compounds (component ii)
Organoaluminum compounds of component (ii) include:
trialkylaluminum such as triethylaluminum, tributylaluminum;
Trialkenyl aluminum such as triisoprenyl aluminum:
dialkylaluminum alkoxides such as diethylaluminum ethoxide and dibutylaluminum butoxide;
alkylaluminum sesquialkoxides such as ethylaluminum sesquiethoxide, butylaluminum sesquibutoxide;

partially halogenated aluminum alkyls such as alkylaluminum dihalogenides such as ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromide and the like;
dialkylaluminum hydride such as diethylaluminum hydride, dibutylaluminum hydride;
partially hydrogenated aluminum alkyls such as alkylaluminum dihydrides such as ethylaluminum dihydride, propylaluminum dihydride;
Partially alkoxylated and halogenated aluminum alkyls such as ethylaluminum ethoxychloride, butylaluminum butoxychloride, ethylaluminum ethoxybromide.

3) electron donor compound (component iii)
The electron donor compounds of component (iii) are commonly referred to as "external electron donors". Organosilicon compounds are preferred as such electron donor compounds. Preferred organosilicon compounds include the following.
trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-amylmethyldiethoxysilane, diphenyldimethoxysilane, phenylmethyl Dimethoxysilane, diphenyldiethoxysilane, bis-o-tolyldimethoxysilane, bis-m-tolyldimethoxysilane, bis-p-tolyldimethoxysilane, bis-p-tolyldiethoxysilane, bisethylphenyldimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane silane, cyclohexylmethyldimethoxysilane, cyclohexylmethyldiethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, t-butyltriethoxysilane, thexyltrimethoxysilane, n-butyltriethoxysilane, iso- butyltriethoxysilane, phenyltriethoxysilane, γ-aminopropyltriethoxysilane, chlorotriethoxysilane, ethyltriisopropoxysilane, vinyltributoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, 2-norbornanetrimethoxysilane , 2-norbornanetriethoxysilane, 2-norbornanemethyldimethoxysilane, ethyl silicate, butyl silicate, trimethylphenoxysilane, methyltriallyloxysilane, vinyltris(β-methoxyethoxysilane), vinyltriacetoxysilane, dimethyl Tetraethoxydisiloxane.

among others ethyltriethoxysilane, n-propyltriethoxysilane, n-propyltrimethoxysilane, t-butyltriethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-butylethyldimethoxysilane, t-butylpropyldimethoxysilane, t-butyl t-butoxydimethoxysilane, t-butyltrimethoxysilane, i-butyltrimethoxysilane, isobutylmethyldimethoxysilane, i-butylsec-butyldimethoxysilane, ethyl (perhydroisoquinoline 2- yl)dimethoxysilane, bis(decahydroisoquinolin-2-yl)dimethoxysilane, tri(isopropenyloxy)phenylsilane, thexyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltri butoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, i-butyl i-propyldimethoxysilane, cyclopentyl t-butoxydimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexyl i-butyldimethoxysilane, cyclopentyl i -butyldimethoxysilane, cyclopentylisopropyldimethoxysilane, di-sec-butyldimethoxysilane, diethylaminotriethoxysilane, tetraethoxysilane, tetramethoxysilane, isobutyltriethoxysilane, phenylmethyldimethoxysilane, phenyltriethoxysilane, bis-p-tolyl Dimethoxysilane, p-tolylmethyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylethyldimethoxysilane, 2-norbornanetriethoxysilane, 2-norbornanemethyldimethoxysilane, diphenyldiethoxysilane, methyl (3,3,3-trifluoropropyl) Dimethoxysilane, ethyl silicate and the like are preferred.

4) Polymerization The raw material monomer is brought into contact with the catalyst prepared as described above to polymerize. At this time, it is preferable to first perform prepolymerization using the catalyst. Prepolymerization is a step of forming a polymer chain in the solid catalyst component, which will serve as a foothold for subsequent main polymerization of the raw material monomers. Prepolymerization can be performed by a known method. Prepolymerization is usually carried out at 40° C. or lower, preferably 30° C. or lower, more preferably 20° C. or lower.
Next, the prepolymerized catalyst is introduced into the polymerization reaction system to carry out the main polymerization of the raw material monomers. In the main polymerization, it is preferable to polymerize the raw material monomer of component (B1) and the raw material monomer of component (B2) using two or more reactors. The polymerization may be carried out in liquid phase, gas phase or liquid-gas phase. The polymerization temperature is preferably normal temperature to 150°C, more preferably 40°C to 100°C. The polymerization pressure is preferably in the range of 3.3-6.0 MPa when carried out in the liquid phase, and in the range of 0.5-3.0 MPa when carried out in the gas phase. Conventional molecular weight modifiers known in the art such as chain transfer agents (eg, hydrogen or ZnEt ₂ ) may be used.

Also, a polymerization vessel having a gradient of monomer concentration and polymerization conditions may be used. Such a polymerization vessel can be used, for example, with at least two connected polymerization zones and can polymerize the monomers by gas phase polymerization. Specifically, in the presence of a catalyst, a monomer is supplied and polymerized in a polymerization region composed of an ascending pipe, a monomer is supplied and polymerized in a descending pipe connected to the ascending pipe, and the ascending pipe and the descending pipe are used. is circulated to recover the polymer product. The method comprises means for wholly or partially preventing the gas mixture present in the riser from entering the downcomer. Also, a gas or liquid mixture is introduced into the downcomer having a different composition than the gas mixture present in the riser. As the above polymerization method, for example, the method described in JP-T-2002-520426 can be applied.

1-4. Blowing Agent The expandable polypropylene composition of the present invention contains a blowing agent. As the foaming agent, either a decomposition type foaming agent or a solvent type foaming agent can be used. A decomposable foaming agent is a compound that decomposes under the cylinder temperature conditions of an injection molding machine to generate gases such as carbon dioxide gas and nitrogen gas. Both inorganic and organic types can be used as the decomposable foaming agent. Further, a known foaming aid such as an organic acid that promotes gas generation may be used in combination.

Examples of inorganic decomposable foaming agents include sodium hydrogen carbonate, sodium carbonate, ammonium hydrogen carbonate, ammonium carbonate, ammonium nitrite, citric acid, and sodium citrate. Examples of organic decomposable blowing agents include N-nitroso compounds such as N,N'-dinitrosoterephthalamide and N,N'-dinitrosopentamethylenetetramine; azodicarbonamide, azobisisobutyronitrile, and azocyclohexyl. azo compounds such as nitriles, azodiaminobenzene, and barium azodicarboxylate; Sulfonyl hydrazide compounds; azide compounds such as calcium azide, 4,4'-diphenyldisulfonyl azide, p-toluenesulfonyl azide, and the like.

Among these foaming agents, carbonates such as sodium hydrogencarbonate or hydrogencarbonates are used from the viewpoint of less environmental impact, safety, and stabilization of foam cells. is preferred, and in that case, an organic carboxylic acid may be used in combination as a foaming aid.

A solvent-based blowing agent is a substance that is injected into a blowing agent-free composition through the cylinder portion of an injection molding machine and evaporates in the injection mold to function as a blowing agent. Low boiling point aliphatic hydrocarbons such as propane, butane, neopentane, heptane, isoheptane, isohexane and hexane, and low boiling point fluorine-containing hydrocarbons represented by freon gas can be used. Alternatively, an inert gas such as nitrogen or carbon dioxide can be pressurized and used as a supercritical fluid blowing agent.

The foaming agent used in the expandable polypropylene composition of the present invention can be added in the form of a foaming agent masterbatch using polyolefin as a carrier. Examples of the polyolefin include polypropylene, polyethylene, polystyrene and the like. The carrier contained in the masterbatch corresponds to other components described later. The content of the decomposition type foaming agent or solvent type foaming agent contained in the foaming agent masterbatch is usually 5 to 50% by weight, preferably 10 to 40% by weight, and commercially available products can be used as they are. The amount of the foaming agent added is usually 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight, and 0.5 ~1 part by weight is more preferred. Furthermore, within this range, the optimum amount is selected in consideration of the amount of generated gas, expansion ratio and the like. The expansion ratio is preferably 1.4 to 3, more preferably 1.5 to 2.8, even more preferably 1.5 to 2.5. An expandable polypropylene composition within this range provides a foam with uniform cell diameters and uniformly dispersed cells.

1-5. Other Ingredients The composition of the present invention contains antioxidants, chlorine absorbers, heat stabilizers, light stabilizers, UV absorbers, internal lubricants, external lubricants, antiblocking agents, antistatic agents, antifog agents, crystals. Conventional additives commonly used in olefin polymers such as nucleating agents, flame retardants, dispersants, copper inhibitors, neutralizers, plasticizers, crosslinkers, peroxides, oil extenders and other organic and inorganic pigments. agents may be added. The amount of each additive to be added may be a known amount.

In addition, the composition of the present invention may be used in addition to polypropylene or the additional elastomer, such as a styrene-based elastomer, a vinyl chloride-based elastomer, a urethane-based elastomer, an ester-based elastomer, an amide-based elastomer, etc., as long as the effects of the present invention are not impaired. It may contain a plastic elastomer. Only one kind of the resin or elastomer may be used, or two or more kinds thereof may be used. The content may be a known amount.

1-6. Composition ratio of components (A1) and (B) The weight blending ratio of the block polypropylene and the masterbatch composition is "50 to 99": "50 to 1", preferably "70 to 98": "30". ~2", more preferably "75-95": "25-5".

2. Method for producing the composition of the present invention The expandable polypropylene composition of the present invention can be produced by any method. For example, the expandable polypropylene composition of the present invention can be produced by dry-blending components (A) to (C) and optional components as necessary and melt-kneading them. Kneading is preferred. When component (A) is previously melt-kneaded, a part or all of component (B) may be melt-kneaded together. However, without adding the component (B) to the pre-kneading with (A), the pre-kneaded component (A), the component (B), and the component (C) are dry-blended and then subjected to injection foam molding. If you provide it, you can improve your work efficiency.

When a decomposable foaming agent is used, the foamable polypropylene composition of the present invention is produced by melt-kneading a part or all of component (A) and component (B) to produce a non-foamable polypropylene composition. and a blowing agent. The dry blend may be melt-kneaded in an extruder attached to a foam molding machine before molding. As described above, a foaming agent masterbatch using polyolefin as a carrier may be used as the foaming agent.

When a solvent-type foaming agent is used, the foaming polypropylene composition can be produced by preparing the non-foaming polypropylene composition and mixing it with the solvent-type foaming agent in an injection molding machine as described above. At this time, a foaming agent masterbatch containing polyolefin or the like as a carrier may be added as a foaming agent.

Melt-kneading conditions are not particularly limited, but the cylinder temperature is preferably 180 to 250°C. The composition of the present invention thus obtained is preferably in the form of pellets. Alternatively, the composition of the present invention can be prepared by metering a dry blend of the above components into an injection molding machine and kneading in a melt kneading section (cylinder). The propylene-ethylene copolymer component of the masterbatch composition exists dispersedly in a matrix containing a propylene (co)polymer as a main component, and the effect of the present invention is exhibited by forming the phase structure. However, since both the masterbatch composition and the block polypropylene forming the matrix are HECO, it is difficult to specifically specify the phase structure.

3. Injection Foam Molding A foam can be produced by foaming the expandable polypropylene composition of the present invention. The foam is preferably manufactured by injection foam molding, which combines an injection process and a foaming process. Injection foam molding can be broadly classified into a method that does not change the volume of the cavity and a method that changes it. The former is a method in which a mold cavity is filled with an expandable polypropylene composition, and the blowing agent is vaporized inside the molded body due to the pressure drop caused by the shrinkage of the polymer to cause foaming. The latter is a method of expanding the volume of the cavity by core-backing the mold or moving a slide core or the like in the mold during or after filling the cavity with the expandable polypropylene composition. be. In the latter case, it is preferable to expand the volume of the cavity faster than the expansion speed of the expandable polypropylene composition. The injection conditions are preferably a cylinder temperature of 190-230° C., a mold temperature of 20-50° C., and an injection speed of 30-300 mm/sec. In injection foam molding, it is preferable to use a counter-pressure method in which gas is previously injected into the mold cavity in order to prevent bubble breakage. The gas injection pressure is preferably 0.3-2 MPa, more preferably 0.3-1 MPa.

1. Production of Masterbatch Composition (Component (B)) A solid catalyst component was prepared according to the preparation method described in the example of JP-A-2011-500907. Specifically, a solid catalyst component was prepared as follows.
Into a nitrogen-purged 500 mL four-necked round bottom flask, 250 mL of _TiCl4 was introduced at 0.degree. While stirring, 10.0 g of microspherical MgCl ₂ .1.8C ₂ H ₅ OH and 9.1 mmol of diethyl-2,3-(diisopropyl)succinate were added. MgCl ₂ .1.8C ₂ H ₅ OH was prepared according to the method described in Example 2 of US Pat. No. 4,399,054, but instead of rotating at 10,000 rpm, it was run at 3000 rpm. The temperature of the contents was raised to 100°C and held for 120 minutes. Agitation was then stopped, the solid product was allowed to settle, and the supernatant liquid was siphoned off. The following procedure was then repeated twice: 250 mL of fresh TiCl ₄ was added, the mixture was allowed to react at 120° C. for 60 minutes, and the supernatant was siphoned off. The solid was washed six times with anhydrous hexane (6 x 100 mL) at 60°C.

The above solid catalyst was mixed with triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (DCPMS) in amounts such that the weight ratio of TEAL to solid catalyst was 18 and the weight ratio of TEAL/DCPMS was 10 at room temperature for 5 minutes. made contact. Prepolymerization was carried out by keeping the resulting catalyst system in suspension in liquid propylene at 20° C. for 5 minutes.

The obtained prepolymer was introduced into the first-stage polymerization reactor to obtain a propylene homopolymer. Thereafter, after purging unreacted monomers from the obtained polymer, the polymer was introduced into the second-stage polymerization reactor to obtain a copolymer (ethylene-propylene copolymer). During the polymerization, temperature and pressure were controlled and hydrogen was used as a molecular weight regulator. As for the ratio of polymerization temperature and reactants, in the first-stage reactor, the polymerization temperature and hydrogen concentration are 70° C. and 0.83 mol %, respectively, and in the second-stage reactor, the polymerization temperature, hydrogen concentration, and C2/( C2+C3) were respectively at 80° C., 100 mol ppm, 0.24 molar ratio. Also, the residence time distribution in the first stage and the second stage was adjusted so that the amount of the copolymer component was 30% by weight. The obtained polypropylene polymer was blended with 0.2% by weight of B225 manufactured by BASF as an antioxidant and 0.05% by weight of calcium stearate manufactured by Tannan Chemical Industry Co., Ltd. as a neutralizer, and mixed with a Henschel mixer. After stirring and mixing for 1 minute, extruded at a cylinder temperature of 230 ° C. with a single screw extruder (NVC manufactured by Nakatani Kikai Co., Ltd.) with a screw diameter of 50 mm, after cooling the strand in water, cut with a pelletizer and pelletized was obtained.

The obtained masterbatch composition (B-1) had an MFR of 10 g/10 min at 230° C. and a load of 2.16 kg, Mw of XI was 13×10 ⁴ , Mw/Mn of XI was 13, and XSIV was 7 dl/g. , the weight ratio of component (B1) to component (B2) was 70:30, and the ethylene-derived units contained in component (B2) was 30% by weight.

2. Production of Expandable Polypropylene Composition (1) Block Polypropylene (Component (A1))
A solid catalyst of Ti and diisobutyl phthalate as an internal donor on _MgCl2 was prepared by the method described in Example 5 of EP 728769. Next, using the solid catalyst, triethylaluminum (TEAL) as an organoaluminum compound, and dicyclopentyldimethoxysilane (DCPMS) as an external electron donor compound, the weight ratio of TEAL to the solid catalyst is 20, and the weight ratio of TEAL/DCPMS of 10 at 12° C. for 24 minutes. Prepolymerization was carried out by keeping the resulting catalyst system in suspension in liquid propylene at 20° C. for 5 minutes. The obtained prepolymer is introduced into the first-stage polymerization reactor of a polymerization apparatus equipped with two-stage polymerization reactors in series to produce a propylene homopolymer. A copolymer was produced. During the polymerization, temperature and pressure were controlled and hydrogen was used as a molecular weight regulator.

As for the ratio of the polymerization temperature and the reactants, in the first stage reactor, the polymerization temperature and hydrogen concentration are 70 ° C. and 1.73 mol ppm, respectively, and in the second stage reactor, the polymerization temperature, hydrogen concentration, C2 / ( C2+C3) were respectively at 80° C., 2.04 mol %, 0.46 mol ratio. Also, the residence time distribution in the first stage and the second stage was adjusted so that the amount of the copolymer component was 30% by weight. The resulting block polypropylene (A1-1) had an MFR of 30 g/10 min at 230° C. and a load of 2.16 kg. The ethylene-derived units of the polymer were 47% by weight, the total ethylene-derived units as component (A1) was 12.2% by weight, and the XSIV was 2.2 dL/g.

(2) homopolypropylene (component (A2))
A propylene homopolymer (A2-1) having an MFR of 1750 g/10 min at 230°C and a load of 2.16 kg and a xylene-soluble content of 2.3% by weight; A propylene homopolymer (A2-2) having a xylene soluble content of 1.5% by weight was used for 10 minutes.

(3) Additional elastomer (component (A3))
Engage 8100 manufactured by Dow Chemical Company (190° C., MFR at 2.16 kg load, 1 g/10 min, density 0.870 g/cm ³ , A3-1) was used.

(4) filler (component (A4)
UNI05 (talc with an average particle size of 5 μm, A4-1) manufactured by Neolite Kosan Co., Ltd. was used.

(5) foaming agent (component (C)
A foaming agent masterbatch (Panthlen H3510, C-1 manufactured by Eiwa Kasei Kogyo Co., Ltd.) of sodium hydrogen carbonate (sodium hydrogen carbonate content=25% by weight) with low-density polyethylene as a carrier was used as the polyolefin component.

[Examples 1 to 4]
Each component of component (A) shown in Table 1 was blended, and 0.05 part by weight of calcium stearate manufactured by Tannan Chemical Industry Co., Ltd. and 0.05 part by weight of B225 manufactured by BASF were added to a total of 100 parts by weight. 20 parts by weight were added. These formulations were melt-kneaded at a die temperature of 220° C. using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd., model number TEX30α) to obtain pellets. The resulting pellets were dry-blended with component (B) and component (C) blowing agent masterbatch to obtain an expandable polypropylene composition. At that time, the blending amount of component (C) was adjusted so as to be 3 parts by weight with respect to the total of 100 parts by weight of component (A1) and component (B). After the obtained expandable polypropylene composition was melt-kneaded in the cylinder of an injection foam molding machine, injection foam molding was performed to produce a foam molded article, which was evaluated by the method described later.

<Molding conditions>
Molding machine: J220EL III manufactured by Japan Steel Works, Ltd.
Screw diameter 53mm, screw stroke 210mm, plasticizing capacity 228kg/h
Molding temperature: 200°C
Mold temperature: 40°C
Foam molding size: (TD) 20 cm x (MD) 40 cm
Molded body thickness before foaming: 1.5 mm
Foam molded body thickness: 2.5 mm
Foaming ratio: 1.67 times Injection speed: 80 mm/sec Cooling time: 30 sec Holding pressure time: None Counter pressure Gas (Air) injection pressure: 1 MPa
Counter pressure Gas (Air) injection time: 1.3 seconds Core back amount (first stage): 0.2 mm
Core back speed (1st stage): 480 mm/sec Core back amount (2nd stage): 1.1 mm
Core back speed (second stage): 2.5 mm/sec

[Example 5]
The components (A) and (B) shown in Table 1 are blended, and 0.05 parts by weight of calcium stearate manufactured by Tannan Chemical Industry Co., Ltd. and B225 manufactured by BASF are added as additives to a total of 100 parts by weight. 0.20 parts by weight was added. These blends were melt-kneaded at a die temperature of 220° C. using a twin-screw extruder (model number TEX-30α manufactured by JSW Co., Ltd.) to obtain pellets. The obtained pellets were dry-blended with a blowing agent masterbatch as component (C) to obtain an expandable polypropylene composition. At that time, the blending amount of component (C) was adjusted so as to be 3 parts by weight with respect to the total of 100 parts by weight of components (A1) and (B). Using the obtained expandable polypropylene composition, a foam molded article was produced in the same manner as in Example 1 and evaluated by the method described later.

[Comparative Example 1]
Each component shown in Table 1 was blended, and in the same manner as in Example 1, a foam molded article for comparison was produced and evaluated.

[Comparative Example 2]
The master batch except that the hydrogen concentration in the first stage reactor was changed to 0.24 mol%, and the hydrogen concentration and C2 / (C2 + C3) in the second stage reactor were changed to 150 mol ppm and 0.27 mol ratio, respectively. A comparative masterbatch composition (B-2) was obtained in the same manner as the composition (B-1). Using this, each component shown in Table 1 was blended, and in the same manner as in Example 1, a foam molded article for comparison was produced and evaluated. The obtained masterbatch composition (B-2) had an MFR of 1 g/10 min at 230° C. and a load of 2.16 kg, Mw of XI was 35×10 ⁴ , Mw/Mn of XI was 14, and XSIV was 7. The weight ratio of (B1) to component (B2) was 70:30, and the ethylene-derived units contained in component (B2) was 32% by weight.

[Comparative Example 3]
Comparison in the same manner as the production of the masterbatch composition (B-1), except that the hydrogen concentration in the first-stage reactor was changed to 0.81 mol% and the hydrogen concentration in the second-stage reactor was changed to 300 mol ppm. to obtain a masterbatch composition (B-3) for Using this, each component shown in Table 1 was blended, and in the same manner as in Example 1, a foam molded article for comparison was produced and evaluated. The obtained masterbatch composition (B-3) had an MFR of 10 g/10 min at 230° C. and a load of 2.16 kg, Mw of XI was 13×10 ⁴ , Mw/Mn of XI was 13, and XSIV was 5. The weight ratio of (B1) to component (B2) was 70:30, and the ethylene-derived units contained in component (B2) was 30% by weight.

3. Evaluation method [MFR]
According to JIS K7210-1, for polypropylene under conditions of temperature 230 ° C and load 2.16 kg based on JIS K6921-2, for polyethylene based on JIS K6922-2, temperature 190 ° C and load 2.16 kg was measured under the conditions of
[Proportions of ethylene-derived units and copolymer components in HECO]
A sample dissolved in a mixed solvent of 1,2,4-trichlorobenzene/deuterated benzene was measured using a Bruker AVANCE III HD400 ( ¹³ C resonance frequency of 100 MHz) at a measurement temperature of 120° C., a flip angle of 45 degrees, and a pulse interval. ^{A 13} C-NMR spectrum was obtained under the conditions of 7 seconds, 20 Hz sample rotation, and 5000 integrations. Using the spectrum obtained above, the component as HECO ( The total ethylene-derived unit amount (% by weight) contained in A1) or component (B) was determined.
Except for using the integrated intensity _T'ββ obtained by the following formula instead of the integrated intensity _Tββ obtained above, the calculation was performed in the same manner as for the total ethylene-derived unit amount, and the copolymer component contained in HECO The amount of ethylene-derived units (% by weight) was determined.
T' _ββ = 0.98 x S _αγ x A/(1-0.98 x A)
where A=S _αγ /(S _αγ +S _αδ )
Proportion of copolymer components contained in HECO (% by weight) = total amount of ethylene-derived units/(amount of ethylene-derived units in copolymer component/100)

[Collection of xylene solubles]
2.5 g of the polymer was placed in a flask containing 250 mL of o-xylene (solvent), and stirred using a hot plate and a reflux apparatus at 135° C. for 30 minutes while purging with nitrogen to completely dissolve the composition. After that, cooling was performed at 25° C. for 1 hour. The resulting solution was filtered using filter paper. 100 mL of the filtrate after filtration was collected, transferred to an aluminum cup or the like, evaporated to dryness at 140° C. while purging with nitrogen, and allowed to stand at room temperature for 30 minutes to obtain xylene solubles (XS). The vessel was then kept under vacuum in an oven at 80° C. until a constant weight was obtained, after which the weight of polymer soluble in xylene at room temperature was determined. The weight percent of polymer soluble in xylene relative to total polymer was calculated and taken as the amount of xylene solubles at 25°C.
[XSIV]
Using the above xylene solubles as a sample, the intrinsic viscosity was measured in tetrahydronaphthalene at 135° C. using an automatic capillary viscometer (SS-780-H1, manufactured by Shibayama Scientific Instruments Co., Ltd.).

[Collection of xylene-insoluble matter]
When the xylene soluble matter was filtered as described above, acetone was added to the residue remaining on the filter paper (mixture of xylene insoluble matter and solvent) and filtered. Evaporate to dryness in a drying oven to obtain xylene insolubles (XI).
[Mw and Mw/Mn of xylene insolubles]
Using the above xylene-insoluble matter as a sample, weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) were measured as follows.
PL GPC220 manufactured by Polymer Laboratories was used as an apparatus, 1,2,4-trichlorobenzene containing an antioxidant was used as a mobile phase, and UT-G (1) and UT-807 (1) manufactured by Showa Denko K.K. were used as columns. A series connection of two UT-806Ms was used, and a differential refractometer was used as a detector. In addition, the same solvent as the mobile phase was used as the solvent for the sample solution of the xylene-insoluble matter, and the sample concentration was 1 mg/mL. 500 μL of the sample solution thus obtained was injected into the column and measured at a flow rate of 1.0 mL/min, a temperature of 145° C., and a data acquisition interval of 1 second. A polystyrene standard sample (shodex STANDARD, manufactured by Showa Denko KK) with a molecular weight of 5,800,000 to 7,450,000 was used to calibrate the column using a cubic approximation. The Mark-Houwink-Sakurada coefficients are K=1.21×10 ⁻⁴ , α=0.707 for the polystyrene standard sample, and K=1.37×10 ⁻⁴ , α=0.707 for the polypropylene-based polymer. 0.75 was used.

[Cell morphology (internal void)]
An injection foam molded product (20 cm×40 cm) was cut in the thickness direction at a length of 10 cm, and the cross section was observed. The presence or absence of internal voids having a size of 1 mm or more in the foam layer was evaluated according to the following criteria.
a: None b: Some c: Multiple

[Hike]
The presence or absence of surface irregularities (sink marks) on the injection foam molded product (20 cm×40 cm) was visually observed.
a: None b: Some c: Multiple

The injection foam molded articles of Examples 1 to 5 obtained using the composition of the present invention had good appearance without internal voids or sink marks. On the other hand, Comparative Example 1 obtained using a composition not containing component (B), Comparative Example 2 obtained using a comparative masterbatch composition (B-2) having an MFR outside the range of the present invention, XSIV The injection foam molded article of Comparative Example 3, which was obtained using the comparative masterbatch composition (B-3) in which the was outside the scope of the present invention, had internal voids and sink marks, and was inferior in appearance.

Claims (9)

50 to 99 parts by weight of block polypropylene containing 5% by weight or more of ethylene as component (A1);
As component (B), 1 to 50 parts by weight of a masterbatch composition containing
Component (B1): a propylene (co)polymer containing 0-3% by weight of ethylene or one or more C4-C10-α-olefin-derived units, and Component (B2): 25-35% by weight of ethylene-derived units. a propylene-ethylene copolymer comprising
For a total of 100 parts by weight of components (A1) and (B),
1 to 40 parts by weight of homopolypropylene as component (A2),
1 to 40 parts by weight of additional elastomer as component (A3),
An expandable polypropylene composition containing more than 0 parts by weight and 40 parts by weight or less of a filler as component (A4) and a blowing agent as component (C),
Requirements for:
1) MFR (230° C., load 2.16 kg) of component (A1) is 5 to 100 g/10 min;
2) The intrinsic viscosity of the component (A1) soluble in xylene is 0.5 to 5.9 dl/g.
3) MFR (230° C., load 2.16 kg) of component (B) is 5 to 30 g/10 min;
4) Mw of the xylene-insoluble portion of component (B) measured by GPC is 10×10 ⁴ to 30×10 ⁴ and Mw/Mn is 6 to 20.
5) The intrinsic viscosity of the component (B) soluble in xylene is 6.0 to 9.0 dl/g.
6) MFR (230 ° C., load 2.16 kg) of the composition excluding the component (C) from the expandable polypropylene composition is 5 to 100 g / 10 minutes.
7) the weight ratio of component (B1):component (B2) is 65-85:15-35;
An expandable polypropylene composition that satisfies The component (B) is
(i) a solid catalyst containing as an essential component an electron donor compound selected from magnesium, titanium, halogen, and succinate compounds;
(ii) an organoaluminum compound; and (iii) a masterbatch composition obtained by polymerizing a monomer using a catalyst comprising an external electron donor compound,
The expandable polypropylene composition of claim 1. The expandable polypropylene composition according to claim 1 or 2, wherein the MFR (230°C, load 2.16 kg) of the expandable polypropylene composition excluding the component (C) is 10 to 70 g/10 minutes. . The expandable polypropylene composition according to any one of claims 1 to 3, wherein the content of component (B) is 2 to 30 parts by weight. The expandable polypropylene composition according to claim 4, wherein the content of component (B) is 5 to 25 parts by weight. The expandable polypropylene according to any one of claims 1 to 5, wherein the component (C) contains 0.1 to 5 parts by weight of a foaming agent with respect to the total of 100 parts by weight of the components (A1) and (B). Composition. A method for producing an injection foam molded article, comprising an injection step of injecting the expandable polypropylene composition according to any one of claims 1 to 6 into a cavity, and a foaming step of expanding the expandable polypropylene composition. The component (A1), the component (B ), the component (A2), the component (A3), the component (A4), and the component (C) are dry blended to prepare the expandable polypropylene composition, and the composition is 8. The method for producing an injection foam molded article according to claim 7 , comprising a step of melting and foaming the . An injection foam molded article obtained by injection molding the expandable polypropylene composition according to any one of claims 1 to 6 .