JP2000159922A - Production of pre-expanded particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a pre-expanded particles excellent in productivity, heat resistance, mechanical strengths, impact strength, lightness or the like by melt- kneading a specific propylene-based polymer composition with a foaming agent, extruding the kneaded product from an extruder while releasing the pressure to provide a foamed strand, and cutting the obtained strand. SOLUTION: A resin composition containing a propylene-based polymer composition, and a foaming agent are melt-kneaded by an extruder at high temperature under high pressure, and the kneaded product is extruded from the extruder while releasing the pressure to provide a foamed strand, and cutting the obtained strand to provide the objective foamed particles. The propylene- based polymer composition consists essentially of (A) a propylene homopolymer or a propylene-olefin copolymer containing >=50 wt.% propylene polymer unit, having 0.2-10 dl/g intrinsic viscosity measured in tetralin at 135 deg.C, and (B) 0.01-5.0 pts.wt. ethylene homopolymer or ethylene-olefin copolymer containing >=50 wt.% ethylene unit, having 15-100 dl/g intrinsic viscosity measured in tetralin at 135 deg.C based on 100 pts.wt. component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a non-crosslinked propylene-based heavy-duty molded article having excellent productivity, heat resistance, mechanical strength, impact resistance, light weight and economical efficiency. The present invention relates to a method for producing pre-expanded particles using a united composition.

[0002]

2. Description of the Related Art A method is known in which pre-expanded thermoplastic resin particles containing a foaming agent are heated and molded in a mold to obtain a molded article having a desired shape. In particular, a molded article using a polypropylene resin as the base resin has an excellent balance of heat resistance, mechanical strength, and impact resistance.

However, in order to produce pre-expanded particles for obtaining an in-mold molded article of a polypropylene resin, conventionally,
The method comprises a step of granulating a polypropylene resin, a step of impregnating a foaming agent under pressure, and a step of producing pre-expanded particles by depressurizing foaming. For this reason, there has been a problem that the equipment becomes large, the acquisition cost thereof becomes high, and a large installation area is required. In addition, because of the batch type, not only the productivity is poor, but also the expansion ratio between the product obtained at the end of pre-expansion and the product obtained at the beginning differs, making it difficult to maintain uniform quality. Was.
Furthermore, when trying to obtain a large amount of pre-expanded particles, it is necessary to repeat the above-described series of steps, particularly heating,
Since the cooling operation has to be performed every time, there is a drawback that the thermal efficiency is very poor and the energy consumption is enormous.

[0004]

Various proposals have hitherto been made to improve such disadvantages. For example,
JP-A-60-168610, JP-A-59-6702
No. 2, JP-A-59-85724 proposes a method of performing all or a part of the above-mentioned steps in a continuous manner. However, even with these methods, the size of the equipment is still inevitable, and the installation place of the equipment is limited, and the molded article using the pre-expanded particles obtained in this way still has a high cost.

On the other hand, JP-A-6-234878 discloses that an extruder has a melt strength of 5 to 40 cN in the presence of a foaming agent.
Of extruding polypropylene resin and cutting foam strands to obtain pre-expanded particles (extruded foam bead method)
The method is relatively excellent in terms of productivity because the above-mentioned pre-expanded particle production step can be simplified to one step to enable continuous production. Also, since the polypropylene resin is not crosslinked, the recyclability is also good. However, the polypropylene resin used in this method is a polymer in which a part of a polymer chain is branched, and to obtain such a polymer, after polymerization of propylene, irradiation with an electron beam or specific irradiation is performed. It must be treated with an organic peroxide. Therefore, expensive processing equipment for that purpose is required, and precise control must be performed so as not to crosslink, so that the price of the raw material resin increases, and the total cost of the molded article is not necessarily reduced.

An object of the present invention is to provide a method for producing pre-expanded particles having uniform and dense foam cells at a low cost.

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that a high molecular weight ethylene (co) polymer having a specific intrinsic viscosity and a propylene (co) polymer having a specific intrinsic viscosity The present inventors have found that the above-mentioned problems can be solved by an extruded foamed bead method using a propylene-based polymer composition containing a polymer and the present invention, and have accomplished the present invention.

[0008]

Means for Solving the Problems The present invention provides the following (a):
A resin composition containing a propylene-based polymer composition containing (b) as a main component and a foaming agent are melt-kneaded under high temperature and high pressure in an extruder, and extruded from an extruder while releasing the pressure to form a foamed strand. A method for producing pre-expanded particles, characterized in that the expanded strand is cut into expanded particles. (A) a propylene homopolymer or a propylene-olefin copolymer containing 50% by weight or more of propylene polymerized units having an intrinsic viscosity of 0.2 to 10 dl / g measured in tetralin at 135 ° C. (collectively, , "Propylene (co) polymer"). (B) An ethylene homopolymer or ethylene polymer unit having an intrinsic viscosity of 15 to 100 dl / g measured in tetralin at 135 ° C. per 100 parts by weight of the component (a)
0.01 to 5.0 parts by weight of an ethylene-olefin copolymer containing 0% by weight or more (collectively referred to as "ethylene (co) polymer").

The propylene polymer composition is used in an amount of 0.01 to 1 mol of the transition metal compound catalyst component and the transition metal atom.
Periodic Table of １０００1000 Mole (1991 Version), Group 1 and 2
A catalyst for the production of a polyolefin comprising a combination of an organometallic compound of a metal selected from the group consisting of metals belonging to Group 12, Group 12 and Group 13 and 0 to 500 moles of an electron donor per mole of a transition metal atom; In the presence of the preactivated catalyst containing the ethylene (co) polymer as the component (b) supported on the catalyst, propylene is polymerized alone or propylene and an olefin other than propylene are copolymerized. It is preferable to produce the propylene (co) polymer of the component (a).

The blowing agent used in the present invention has a boiling point of-
It is preferably at least one compound selected from the group consisting of hydrocarbons having a temperature of 50 to 100 ° C, halogenated hydrocarbons having a boiling point of -50 to 100 ° C, and inorganic gas.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION (b) of a propylene polymer composition
The ethylene (co) polymer as a component has an intrinsic viscosity measured in tetralin at 135 ° C. (hereinafter, measurement of intrinsic viscosity is as follows:
All were performed with the same solvent and measurement temperature. ) Is 15-100
dl / g, preferably 17 to 50 dl / g. As described above, since it is necessary to increase the intrinsic viscosity to 15 dl / g or more, the ethylene (co) polymer of the component (b) has an ethylene polymerized unit of 50% by weight or more from the viewpoint of the efficiency of increasing the molecular weight. Is preferred. That is, an ethylene homopolymer or an ethylene-olefin copolymer containing 50% by weight or more, preferably 70% by weight or more, particularly preferably 90% by weight or more of ethylene polymer units is suitable. In addition, a mixture of two or more kinds may be used.

When the intrinsic viscosity of the ethylene (co) polymer of the component (b) is less than 15 dl / g, the bubble diameter of the obtained pre-expanded particles tends to be non-uniform, and in some cases, the cells are broken to open cells. Increase. Further, a molded article using such pre-expanded particles has impaired appearance due to sink marks and dimensional shrinkage. The upper limit of the intrinsic viscosity is not particularly limited, but if the difference between the intrinsic viscosity of the propylene (co) polymer of the component (a) and the intrinsic viscosity of the propylene (co) polymer is large, the propylene (co) Dispersion of the ethylene (co) polymer of the component (b) in the coalesce becomes worse,
As a result, the strength at the time of melting does not increase, and the effect of improving the moldability becomes insufficient. Further, from the viewpoint of production efficiency, the upper limit of the intrinsic viscosity of the ethylene (co) polymer is preferably about 100 dl / g.

When the component (b) is an ethylene copolymer, the olefin other than ethylene copolymerized with ethylene is not particularly limited, but an olefin having 3 to 12 carbon atoms is preferably used. Specifically, propylene,
Examples thereof include 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1-pentene. There may be more than one species.

The density of the ethylene (co) polymer of the component (b) is not particularly limited, but is specifically 0.88.
Those having about 0 to 0.980 g / cm ³ are preferable.

The propylene (co) polymer of the component (a) constituting the propylene polymer composition has an intrinsic viscosity of 0.2 to 10 dl / g, preferably 0.5 to 8 dl / g.
g, more preferably from 1.0 to 5.0 dl / g of crystalline propylene (co) polymer, less than 0.2 dl / g or more than 10 dl / g, the moldability of the pre-expanded particles Worsens. The propylene (co) polymer is a propylene homopolymer or a propylene-olefin random copolymer or a propylene-olefin block copolymer containing 50% by weight or more, preferably 70% by weight or more of propylene polymerized units. Considering that the pre-expanded particles can be fused to each other during in-mold molding and that the temperature during in-mold foaming does not need to be too high, a propylene-olefin random unit having a propylene polymerized unit content of 80 to 99% by weight is considered. Copolymers are particularly preferred. These polymers may be not only one kind but also a mixture of two or more kinds.

When the component (a) is a propylene copolymer, the olefin other than propylene to be copolymerized with propylene is not particularly limited, but an olefin having 2 to 12 carbon atoms is preferably used. Specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, 3-
Examples thereof include methyl-1-pentene, and the number of these olefins may be one or more.

There is no particular limitation on the stereoregularity of the propylene (co) polymer of component (a).
Any propylene (co) polymer may be used. Specifically, the isotactic pentad fraction (mmmm) measured by ¹³ C-NMR (nuclear magnetic resonance spectrum) is 0.80 to 0.99, preferably 0.85 to 0.99. A propylene (co) polymer is used.

Isotactic pentad fraction (mmm
m) refers to ¹³ C-NMR proposed by A. Zambelli et al. (Macromolecules 6 , 925 (1973)).
Is the isotactic fraction in pentad units in the polypropylene molecular chain, as determined by the method of A. Samberg (AZ
ambelli) et al. (Macromolecules 8 , 687 (197
5) Determined according to the attributions made. Specifically, o-
Using a solution having a polymer concentration of 20% by weight in a mixed solvent of dichlorobenzene / brominated benzene = 8/2 by weight,
It is determined by measuring at 7.20 MHz and 130 ° C. As a measuring device, for example, JEOL-GX
A 270 NMR measurement device (manufactured by JEOL Ltd.) is used.

In the present invention, between the melt tension MS (unit: cN) at 230 ° C. of the propylene polymer composition and its intrinsic viscosity [η _I ] (unit: dl / g), log (MS)> It is preferable to have a relationship represented by 4.24 × log [η _I ] -1.10. Melt tension MS
When the particle size is small, it is difficult to hold a foaming agent (including a component generated by the decomposition of the foaming agent) in the molten resin. Be a body. The upper limit is not particularly limited, but if the melt tension MS is too large, it becomes difficult to produce pre-expanded particles having a high expansion ratio.

Here, the melt tension MS at 230 ° C.
Was heated to 230 ° C. in an apparatus using a melt tension tester type 2 (manufactured by Toyo Seiki Seisaku-sho, Ltd.), and the molten propylene polymer composition was heated to a diameter of 2.095 mm. A value obtained by extruding from a nozzle into the atmosphere at 23 ° C. at a speed of 20 mm / min to form a strand, and measuring the tension of the filamentous propylene-based polymer composition when the strand is taken off at a speed of 3.14 m / min (unit: c)
N).

In the propylene polymer composition used in the present invention, it is preferable that the ethylene (co) polymer of the component (b) is dispersed as fine particles in the composition. The ethylene (co) polymer has a number average particle diameter of 1 to 5000 nm.
Is preferable, and the range of 10 to 500 nm is particularly preferable.

As a method for producing the propylene-based polymer composition used in the present invention, any production method may be employed, but a catalyst preactivated by ethylene or a mixture of ethylene and other olefins may be used. A method of polymerizing propylene alone or propylene and an olefin other than propylene in the presence is preferred.

In the present invention, the term "pre-activation" means to pre-activate a catalyst for producing polyolefin before conducting propylene homopolymerization or copolymerization of propylene with another olefin. The polymerization is carried out by polymerizing ethylene alone or copolymerizing ethylene with other olefins in the presence of a catalyst for use, and supporting a small amount of an ethylene (co) polymer on the catalyst. Prior to supporting the ethylene (co) polymer, prepolymerization with propylene alone or a mixture of propylene and other olefins is performed to support a small amount of the propylene (co) polymer for the purpose of increasing the polymerization efficiency. It is desirable. At this time, a polymer of an olefin other than propylene may be supported by prepolymerization instead of or in addition to the propylene (co) polymer.

That is, a preferred preactivation catalyst in the present invention is a transition metal compound catalyst component containing a titanium compound or the like, a periodic table (1991 edition) Group 1 of 0.01 to 1000 mol per mol of transition metal atom. 0 to 1 mol of an organometallic compound of a metal selected from the group consisting of metals belonging to Group 2, 12 and 13 and transition metal atoms.
A catalyst for polyolefin production comprising a combination of 500 mol of an electron donor, and 0.01-100 g per gram of a transition metal compound catalyst component in the catalyst supported on the catalyst.
A propylene (co) polymer having an intrinsic viscosity of less than 15 dl / g;
1 to 5000 g of an ethylene (co) polymer having an intrinsic viscosity of 15 to 100 dl / g.

In the above-mentioned preactivated catalyst for olefin (co) polymerization, any of the known catalyst components mainly composed of the transition metal compound catalyst component proposed for polyolefin production can be used as the transition metal compound catalyst component. Can also be used. Among them, a titanium-containing solid catalyst component is preferably used in industrial production.

As the titanium-containing solid catalyst component, a titanium-containing solid catalyst component containing a titanium trichloride composition as a main component (JP-B-56-3356, JP-B-59-2857)
No. 3, JP-B-63-66323, and the like, and a titanium-containing supported catalyst component in which titanium tetrachloride is supported on a magnesium compound and titanium, magnesium, halogen, and an electron donor are essential components (Japanese Patent Application Laid-Open No. Sho 62-63). -10481
0, Japanese Patent Application Laid-Open No. 62-104811, Japanese Patent Application Laid-Open
JP-A-2-104812, JP-A-57-63310, JP-A-57-63311, JP-A-58-83
006, JP-A-58-138712) and the like, and any of these can be used.

As a transition metal compound catalyst component other than the above, a transition metal compound having at least one π-electron conjugated ligand usually called a metallocene can also be used. The transition metal at this time is Zr, Ti, Hf, V, N
It is preferable to select from b, Ta and Cr.

Specific examples of the π-electron conjugated ligand include η-
A ligand having a cyclopentadienyl structure, an η-benzene structure, an η-cycloptatetrienyl structure, or an η-cyclooctatetraene structure may be mentioned, and particularly preferred is an η-cyclopentadienyl structure. Ligand.

Examples of the ligand having an η-cyclopentadienyl structure include a cyclopentadienyl group, an indenyl group, a fluorenyl group and the like. These groups include hydrocarbon groups such as alkyl groups, aryl groups and aralkyl groups, silicon-substituted hydrocarbon groups such as trialkylsilyl groups, halogen atoms, alkoxy groups, aryloxy groups, chain and cyclic alkylene groups, and the like. It may be replaced.

When the transition metal compound contains two or more π-electron conjugated ligands, two of the π-electron conjugated ligands may be an alkylene group, a substituted alkylene group, a cycloalkylene group, a substituted cycloalkylene group. , A substituted alkylidene group, a phenyl group, a silylene group, a substituted dimethylsilylene group, a germyl group, or the like. The transition metal catalyst component at this time includes, in addition to having at least one π-electron ligand as described above, a hydrocarbon group such as an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group, and a silicon-substituted hydrocarbon group. , An alkoxy group, an aryloxy group, a substituted sulfonato group, an amidosilylene group, an amidoalkylene group and the like. Note that a divalent group such as an amidosilylene group or an amidoalkylene group may be bonded to a π-electron conjugated ligand.

As described above, π which is usually called metallocene
The transition metal compound catalyst component having at least one electron conjugated ligand can be used by being supported on a fine particle carrier. As such a particulate carrier, an inorganic or organic compound having a particle diameter of 5 to 300 μm, preferably 10 to 200 μm, is used. Among them, the inorganic compound is SiO.
₂ , Al ₂ O ₃ , MgO, TiO ₂ , ZnO and the like or a mixture thereof. Among these, SiO ₂ or A
Those containing l ₂ O ₃ as a main component are preferred. The organic compound used for the carrier includes ethylene, propylene,
-Carbon number of 2-1 such as butene and 4-methyl-1-pentene;
And a polymer or copolymer of styrene or a styrene derivative.

As the organometallic compound, a periodic table (199)
1 year version) Compounds having an organic group of a metal selected from the group consisting of metals belonging to Group 1, Group 2, Group 12 and Group 13, such as organic lithium compounds, organic sodium compounds, organic magnesium compounds, Organic zinc compounds, organic aluminum compounds and the like can be mentioned, and one or more of these can be used in combination with the transition metal compound catalyst component.

In particular, when the general formula is AlR ¹ _p R ² _q X
_{3- (p + q)} (wherein, R ¹ and R ² are the same or different of a hydrocarbon group such as an alkyl group, a cycloalkyl group and an aryl group and an alkoxy group, X represents a halogen atom,
p and q represent an integer of 0 <p + q ≦ 3), and an organoaluminum compound represented by the formula (1) can be preferably used.

Specific examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, tri-i-butylaluminum, tri-n-hexylaluminum, tri-i-aluminum. Hexyl aluminum, trialkyl aluminum such as tri-n-octyl aluminum, diethyl aluminum chloride, di-n-propyl aluminum chloride, di-i
-Dialkylaluminum monohalides such as butylaluminum chloride, diethylaluminum bromide and diethylaluminum iodide; dialkylaluminum hydrides such as diethylaluminum hydride; alkylaluminum sesquihalides such as ethylaluminum sesquichloride; monoalkylaluminum dihalides such as ethylaluminum dichloride. In addition to the above, an alkoxyalkylaluminum such as diethoxymonoethylaluminum can also be mentioned, and among them, a trialkylaluminum or a dialkylaluminum monohalide can be suitably used.
These organoaluminum compounds are not only one kind but also two kinds.
Mixtures of more than one type can also be used.

Also, an aluminoxane compound can be used as the organometallic compound. Aluminoxane is an organoaluminum compound represented by the following general formula (1) or (2).

[0036]

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[0037]

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In the chemical formulas 1 and 2, R represents a carbon number of 1 to
6, preferably a hydrocarbon group of 1-4, specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group;
An alkenyl group such as an allyl group, a 2-methylallyl group, a propenyl group, an isopropenyl group, a 2-methyl-1-propenyl group and a butenyl group, a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group; And a compound such as an aryl group. Of these, particularly preferred is an alkyl group, and each R may be the same or different. p is 2 to 40
And preferably 6 to 30, particularly preferably 8 to 30.

As the organometallic compounds that can be used,
Further, a boron-based organometallic compound can also be mentioned. The boron-based organometallic compound is obtained by reacting a transition metal compound with an ionic compound containing a boron atom or a Lewis acid containing a boron atom. As the transition metal compound used at this time, those similar to the transition metal compound catalyst component used in producing the preactivated catalyst for olefin (co) polymerization can be used. And a transition metal compound catalyst component having at least one π-electron conjugated ligand usually referred to as a metallocene.

Specific examples of the ionic compound containing a boron atom include triethylammonium tetrakis (pentafluorophenyl) borate, tri-n-butylammonium tetrakis (pentafluorophenyl) borate, and trikis (tetrafluorophenyl) borate. Examples include phenyl ammonium, methyl ammonium tetrakis (pentafluorophenyl) borate, tridimethylammonium tetrakis (pentafluorophenyl) borate, and trimethylammonium tetrakis (pentafluorophenyl) borate.

As the boron atom-containing Lewis acid, compounds represented by the following general formula 3 can be used.

Embedded image BR ¹ R ² R ³ (wherein R ¹ , R ² and R ³ each independently represent a phenyl group which may have a substituent such as a fluorine atom or a fluorinated methyl group, or an alkyl Represents a group.)

Specific examples of the compound represented by the above general formula include tri (n-butyl) boron, triphenylboron, tris [3,5-bis (trifluoromethyl) phenyl] boron, tris (4-fluoro Methylphenyl)
Examples thereof include boron, tris (3,5-difluorophenyl) boron, tris (2,4,6-trifluorophenyl) boron, and tris (pentafluorophenyl) boron. Tris (pentafluorophenyl) boron is particularly preferred.

An electron donor is used as needed for the purpose of controlling the production rate and / or stereoregularity of the polyolefin. Examples of the electron donor include ethers, alcohols, esters, aldehydes, fatty acids, ketones, nitriles, amines, amides, ureas and thioureas, isocyanates, azo compounds, phosphines, and phosphines. Any one of oxygen, nitrogen, sulfur, and phosphorus in the molecule of phytes, phosphinites, hydrogen sulfide and thioethers, neoalcohols, etc.
Examples thereof include a compound having a species or two or more atoms, and an organosilicon compound.

As ethers, dimethyl ether,
Diethyl ether, di-n-propyl ether, di-n
-Butyl ether, di-i-amyl ether, di-n-
Pentyl ether, di-n-hexyl ether, di-i
-Hexyl ether, di-n-octyl ether, di-i
-Octyl ether, di-n-dodecyl ether, diphenyl ether, ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and the like, alcohols such as methanol,
Ethanol, propanol, butanol, pentanol, hexanol, octanol, 2-ethylhexanol, allyl alcohol, benzyl alcohol, ethylene glycol, glycerin, etc., and phenols such as phenol, cresol, xylenol, ethyl phenol, naphthol, etc. .

Examples of the esters include methyl methacrylate, methyl formate, methyl acetate, methyl butyrate, ethyl acetate, vinyl acetate, n-propyl acetate, i-propyl acetate, butyl formate, amyl acetate, and n-butyl acetate. Octyl acetate, phenyl acetate, ethyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, 2-ethylhexyl benzoate, methyl toluate, ethyl toluate, methyl anisate, Monocarboxylic acid esters such as ethyl anisate, propyl anisate, phenyl anisate, ethyl cinnamate, methyl naphthoate, ethyl naphthoate, propyl naphthoate, butyl naphthoate, 2-ethylhexyl naphthoate, and ethyl phenylacetate , Diethyl succinate, methyl malonate Aliphatic polycarboxylic acid esters such as butyl, diethyl butylmalonate, dibutyl maleate and diethyl butylmaleate, monomethyl phthalate, dimethyl phthalate, diethyl phthalate, di-n-propyl phthalate and mono-phthalate. n-butyl, di-n-butyl phthalate, di-i-butyl phthalate, di-n-heptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diethyl i-phthalate, i-
Dipropyl phthalate, dibutyl i-phthalate, di-2-ethylhexyl i-phthalate, diethyl terephthalate,
Aromatic polycarboxylic acid esters such as dipropyl terephthalate, dibutyl terephthalate, and di-i-butyl naphthalenedicarboxylate are exemplified.

Examples of aldehydes include acetaldehyde, propionaldehyde, and benzaldehyde, and examples of carboxylic acids include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, succinic acid, acrylic acid, maleic acid, valeric acid, and benzoic acid. Acids and acid anhydrides such as benzoic anhydride, phthalic anhydride and tetrahydrophthalic anhydride, and ketones such as acetone, methyl ethyl ketone, methyl-i-butyl ketone and benzophenone are exemplified.

Examples of the nitrogen-containing compound include nitriles such as acetonitrile and benzonitrile, methylamine, diethylamine, tributylamine, triethanolamine, β (N, N-dimethylamino) ethanol, pyridine, quinoline, α-picoline, , 4,6-trimethylpyridine, 2,2,5,6-tetramethylpiperidine,
2,2,5,5, tetramethylpyrrolidine, N, N,
Amines such as N ′, N′-tetramethylethylenediamine, aniline, dimethylaniline, formamide, hexamethylphosphoric triamide, N, N, N ′, N ′,
Amides such as N ″ -pentamethyl-N′-β-dimethylaminomethylphosphoric acid triamide, octamethylpyrophosphoramide, ureas such as N, N, N ′, N′-tetramethylurea, phenylisocyanate, toluyl Examples include isocyanates such as isocyanate and azo compounds such as azobenzene.

Examples of the phosphorus-containing compound include phosphines such as ethyl phosphine, triethyl phosphine, tri-n-octyl phosphine, triphenyl phosphine, and triphenyl phosphine oxide; dimethyl phosphite;
Phosphines such as di-n-octylphosphine, triphenylphosphine and triphenylphosphine oxide, dimethyl phosphite, di-n-octyl phosphite, triethyl phosphite, tri-n-butyl phosphite and triphenyl phosphite; Phosphites are exemplified.

Examples of the sulfur-containing compound include thioethers such as diethylthioether, diphenylthioether, and methylphenylthioether; ethylthioalcohol;
thioalcohols such as n-propylthioalcohol and thiophenol; and further, as an organosilicon compound, trimethylsilanol, triethylsilanol,
Silanols such as triphenylsilanol, trimethylmethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, diphenyldimethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, -I-propyldimethoxysilane, di-i-butyldimethoxysilane, diphenyldiethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane, phenyltriethoxysilane, ethyltriisopropoxysilane , Vinyltriacetoxysilane, cyclopentylmethyldimethoxysilane, cyclopentyltrimethoxysilane, dicyclopentyldimethoxy Silane, cyclohexyl methyl dimethoxy silane, cyclohexyl trimethoxy silane, dicyclohexyl dimethoxysilane, in the molecule such as 2-norbornyl methyl dimethoxy silane Si-O-C
Examples thereof include alkoxysilanes having a bond. These electron donors can be used alone or in combination of two or more.

The amount of the ethylene (co) polymer, which is the component (b) of the propylene polymer composition, per g of the transition metal compound catalyst component in the preactivated catalyst is 0.0
1 to 5,000 g, preferably 0.05 to 2,000
g, more preferably 0.1 to 1,000 g. The supported amount is 0.01 g per 1 g of the transition metal compound catalyst component.
If it is less than 1, the effect of improving the melt tension of the propylene polymer composition obtained using the preactivated catalyst is insufficient, and the effect of improving the moldability is insufficient. Also 5,000
If the amount exceeds 0 g, not only the improvement of those effects will not be remarkable but also the homogeneity of the propylene-based polymer composition may deteriorate, which is not preferable.

On the other hand, the propylene (co) polymer in the preactivation catalyst has an intrinsic viscosity of 15 dl / g as described above.
A smaller propylene (co) polymer, wherein the supported amount per gram of the transition metal compound catalyst component is 0.01 to 100.
The range of g is preferred. The propylene (co) polymer is incorporated as a part of the component (a) of the propylene polymer composition.

The pre-activated catalyst is preferably produced by the pre-activation treatment described below. That is, the transition metal compound catalyst component is added in an amount of 0.1 to 1 mol of the transition metal in the catalyst component.
01 to 1,000 mol, preferably 0.05 to 500 mol, of the organometallic compound and 0 to 1 mol of the transition metal
A catalyst for producing a polyolefin comprising a combination of an electron donor in an amount of from 0.001 to 5,000 mmol, in terms of transition metal atoms in the catalyst component, per liter of polymerization volume, It is preferably present in an amount of 0.01 to 1,000 mmol, and in the absence of a solvent or in the presence of up to 100 liters of a solvent per 1 g of the transition metal compound catalyst component, the required amount of propylene alone or propylene and other olefins is converted. The mixture is supplied and prepolymerized to produce 0.01 to 100 g of a propylene (co) polymer per 1 g of the transition metal compound catalyst component, and then a required amount of ethylene alone or a mixture of ethylene and another olefin is supplied. The pre-activated polymerization is performed, and the transition metal compound is used in an amount of 0.01 to 1 g per 1 g of the catalyst component.
By generating 5,000 g of an ethylene (co) polymer, the transition metal compound catalyst component is coated and supported with a propylene (co) polymer and an ethylene (co) polymer. In the present specification, the term “polymerization volume” refers to the volume of the liquid phase portion in the polymerization vessel in the case of liquid phase polymerization, and the volume of the gas phase portion in the polymerization vessel in the case of gas phase polymerization. Means

The amount of the transition metal compound catalyst component used is preferably within the above range in order to maintain an efficient and controlled polymerization reaction rate. Further, if the amount of the organometallic compound is too small, the polymerization reaction rate becomes too slow, and even if it is too large, a corresponding increase in the polymerization reaction rate cannot be expected. It is not preferable because the residual metal compound increases.
Further, when the amount of the electron donor is too large, the polymerization reaction rate is reduced.

The preactivation treatment can be performed in a liquid phase using a solvent as described above, or can be performed in a gas phase without using a solvent. If the solvent is used in an excessively large amount, not only a large reaction vessel is required, but also it is difficult to efficiently control and maintain the polymerization reaction rate. Examples of the solvent include aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane, isooctane, decane and dodecane; cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane; toluene, xylene and ethylbenzene. Aromatic hydrocarbons,
In addition, an inert solvent such as a gasoline fraction or a hydrogenated diesel oil fraction, or an olefin itself can be used.

The pre-activation treatment may be carried out in the presence of hydrogen, but has an intrinsic viscosity of 15 to 100 dl / g.
In order to produce a high molecular weight ethylene (co) polymer, it is preferable not to use hydrogen.

The pre-polymerization conditions of propylene alone or a mixture of propylene and other olefins in the pre-activation treatment are such that a propylene (co) polymer is produced in an amount of 0.01 g to 100 g per 1 g of the transition metal compound catalyst component. Well, usually under the temperature of -40 ℃ ~ 100 ℃,
Under a pressure of 0.1 MPa to 5 MPa, a polymerization reaction is performed for 1 minute to 24 hours by supplying 0.01 to 500 g of monomer per 1 g of the transition metal compound catalyst component. The preactivation polymerization conditions for ethylene alone or a mixture of ethylene and another olefin are as follows: the ethylene (co) polymer is used in an amount of 0.01 to 5,000 g, preferably 0.05 to 2,000 g, per gram of the transition metal compound catalyst component. 000 g, more preferably 0.1 g.
There is no particular limitation as long as the condition is such that it is produced in an amount of 1 to 1,000 g.
Under a relatively low temperature of about 40 ° C. to 30 ° C., more preferably about −40 ° C. to 20 ° C., 0.1 MPa to 5 MPa, preferably 0.2 MPa to 5 MPa, particularly preferably 0.3 M
Under the pressure of Pa to 5 MPa, the transition metal compound catalyst component 1
The polymerization reaction is carried out for 1 minute to 24 hours, preferably for 5 minutes to 18 hours, particularly preferably for 10 minutes to 12 hours, by supplying 0.01 to 10,000 g of the monomer per g.

Further, after the preactivation treatment, additional polymerization with propylene alone, a mixture of propylene and other olefins, or an olefin other than propylene is carried out for the purpose of suppressing a decrease in polymerization activity due to the preactivation treatment. The amount of the propylene (co) polymer or the olefin polymer other than propylene per 1 g of the transition metal compound catalyst component may be in the range of 0.01 to 100 g. In this case, the amount of the organometallic compound, the electron donor, the solvent, and the like can be used in the same range as in the preactivated polymerization using ethylene or a mixture of ethylene and other olefins. 0.005 to 10 mol, preferably 0.01 to 5
It is preferred to work in the presence of a molar electron donor. Also,
The reaction conditions are as follows: at a temperature of −40 to 100 ° C., 0.1
It is performed under a pressure of ５5 MPa for 1 minute to 24 hours.

The preactivated catalyst is used as it is as a catalyst for olefin (co) polymerization, or is used for polymerization for obtaining a propylene polymer composition further containing an additional organometallic compound and an electron donor. At this time, the amount of the additional organometallic compound used is 0.05 to 3,000 mol in total with the organometallic compound in the preactivation catalyst per 1 mol of the transition metal atom in the preactivation catalyst, preferably 0.
The amount of the additional electron donor is in the range of 1 to 1,000 mol, and the total amount of the additional electron donor and the electron donor in the preactivated catalyst is 0 to 5,000 mol, preferably 0 to 3,000 mol. It is better to be within the range.

If the total content of the organometallic compounds is too small, the polymerization reaction rate in the polymerization for obtaining the propylene-based polymer composition is too slow. On the other hand, if it is excessively large, the polymerization reaction rate is expected. Such an increase is not recognized, which is not only inefficient, but also unfavorably because the organometallic compound residue remaining in the propylene polymer composition finally obtained increases. Further, when the total content of the electron donor becomes excessive, the polymerization reaction rate is remarkably reduced.

As for the kind of the organometallic compound and the electron donor that are additionally used as necessary for the preactivation catalyst, the same organic metal compounds and electron donors as those already exemplified can be used. One type may be used alone, or two or more types may be used in combination. Further, they may be the same or different from those used in the preliminary activation treatment.

When adding the organometallic compound and the electron donor, the solvent, unreacted olefin, the organometallic compound and the electron donor which are present in the preactivated catalyst are removed by filtration or decantation. Alternatively, the solvent and unreacted olefin are removed by evaporation under reduced pressure distillation or an inert gas stream to form a powder, and then the obtained powder or a suspension obtained by adding a solvent to the powder is used. The suspension may be combined with an additional organometallic compound and optionally an electron donor to provide a catalyst for olefin (co) polymerization.

In the method for producing a propylene polymer composition, the amount of the olefin (co) polymerization catalyst used is 0.001 to 1,000 in terms of transition metal atoms in the catalyst per liter of polymerization volume. Mmol, preferably 0.
005-500 mmol. By setting the amount of the transition metal compound catalyst component in the above range, an efficient and controlled (co) polymerization reaction rate of propylene alone or a mixture of propylene and another olefin can be maintained.

In the polymerization of propylene alone or a mixture of propylene and another olefin to obtain a propylene-based polymer composition, a known olefin polymerization process can be used as the polymerization process. A slurry polymerization method in which olefin is polymerized in an inert solvent, a bulk polymerization method in which olefin itself is used as a solvent, a gas phase polymerization method in which olefin is polymerized in a gas phase, and a polyolefin formed by polymerization is in a liquid state. Or a polymerization process combining two or more of these processes.

When using any of the above polymerization processes, the polymerization conditions include a polymerization temperature of 20 to 120 ° C., preferably 30 to 100 ° C., and particularly preferably 40 to 100 ° C.
° C, the polymerization pressure is 0.1 to 5 MPa, preferably in the range of 0.3 to 5 MPa, continuous, semi-continuous,
Alternatively, the polymerization time in the range of about 5 minutes to 24 hours is employed in a batch manner. By employing the above polymerization conditions, a propylene (co) polymer, which is the component (a) of the propylene polymer composition, can be produced with high efficiency and a controlled reaction rate.

For controlling the molecular weight of the propylene (co) polymer, it is effective to use a molecular weight regulator such as hydrogen during the polymerization, and by adjusting the amount used, the intrinsic property of the propylene (co) polymer can be improved. The viscosity can be adjusted to suit the purpose of the present invention. After completion of the polymerization reaction, a propylene-based polymer composition can be obtained through post-treatment steps such as a known catalyst deactivation treatment step, a catalyst residue removal step, and a drying step, if necessary.

In the present invention, not only the propylene polymer composition can be used alone, but also other resins can be mixed with the propylene polymer composition.
Other resins include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, ethylene resins such as ethylene-vinyl acetate copolymer, and syndiotactic polypropylene. , Butene resin, cyclic olefin resin,
Examples thereof include a heat-softening resin such as a petroleum resin, a styrene-based resin, an acrylic-based resin, a fluorine-based resin, ethylene-propylene rubber, and ethylene-butene rubber, and not only one kind but also two or more kinds can be used. The compounding amount is preferably at most about 50 parts by weight based on 100 parts by weight of the propylene-based polymer composition.

Further, in addition to the above-mentioned components, the propylene-based polymer composition of the present invention may contain, as stabilizers, antioxidants, neutralizers, weathering agents, ultraviolet absorbers, and other additives such as antistatic agents. , Lubricants, flame retardants, colorants, and talc,
Inorganic fillers such as calcium carbonate and the like can be blended within a range that does not impair the purpose of the present invention.

For mixing the above-mentioned components, a conventional mixer such as a Henschel mixer (trade name) or a super mixer (trade name), a high-speed mixer, a ribbon blender or a tumbler may be used. . When melt kneading is required, a usual single screw extruder or twin screw extruder is used. The kneading temperature is generally from 190 to 300 ° C, preferably from 200 to 270 ° C, more preferably from 200 to 250 ° C.

The method for producing pre-expanded particles according to the present invention relates to a resin composition comprising the propylene polymer composition and other additives such as a resin, a heat stabilizer and an inorganic filler, if necessary.
(Hereinafter, referred to as “resin composition A”) and a foaming agent are melt-kneaded in an extruder under high temperature and high pressure, and the melt-kneaded product is released under pressure through a porous die or the like attached to the extruder tip. In this method, foamed strands are extruded from an extruder, and then the foamed strands are cut into pre-expanded particles.

In the production of the pre-expanded particles of the present invention,
When extruding the mixture of the resin composition A and the foaming agent while releasing the pressure from the inside of the extruder, foaming is performed by expanding the foaming agent in the molten mixture. If the viscosity is reduced, the foaming agent escapes without being retained in the molten mixture, resulting in insufficient foaming or an open-cell foam. Conversely, if the melt-kneading temperature is lowered in order to increase the viscosity of the molten mixture, the crystallization of the resin component proceeds, and foaming becomes insufficient or uniform foaming hardly occurs. Furthermore, because irregularities occur on the surface of the pre-expanded particles,
The filling of the pre-expanded particles into the mold is not performed smoothly.
The temperature range suitable for the foaming varies depending on the crystallization temperature and molecular weight of the resin used, and also varies depending on the amount of the foaming agent. Generally, when a resin having a low crystallization temperature and a small molecular weight is used, or when the amount of a foaming agent is large, the temperature suitable for extrusion foaming becomes low.

Examples of the extruder used for producing the pre-expanded particles include a one-stage type extruder and a two-stage type (tandem type) in which two extruders are connected in series. The two-stage method is particularly preferable for efficiently performing plasticization of the resin, mixing of the resin and the additive, and cooling of the resin, followed by extrusion to obtain a foam having uniform foam cells.

There are various methods for cutting the extruded foamed strand. A so-called hot-cut method, in which the foamed strand is cut while cooling while it is being foamed out of a porous die, has a shape of the obtained pre-expanded particles. It is preferable because it is rounded and can be smoothly filled into the mold.

As the foaming agent, inorganic gas, volatile foaming agent,
A decomposition type foaming agent or the like can be used. Inert gases such as carbon dioxide, nitrogen and water vapor can be used as the inorganic gas, and aliphatic hydrocarbons such as propane, n-butane, i-butane, pentane, cyclopentane and heptane as the volatile blowing agents And halogenated hydrocarbons such as trichlorofluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethane, tetrafluoroethane, and methyl chloride. Azodicarbonamide, dinitrosopentamethylenetetramine, sodium bicarbonate, citric acid, and the like can be used as the decomposition-type foaming agent, but inorganic gas and Volatile blowing agents are preferred. In particular, butane as a hydrocarbon, tetrafluoroethane as a halogenated hydrocarbon, and carbon dioxide as an inorganic gas are preferable in view of the quality and economic efficiency of the foamed molded article. In addition, these foaming agents can also be used in mixture.

In the case of a non-decomposable foaming agent having a low boiling point, the resin composition is usually melted in an extruder, and then the foaming agent is added through a barrel hole provided in the extruder. In the case of a decomposable foaming agent, it is preliminarily mixed with the resin composition and then introduced into an extruder.

In the present invention, a cell regulator (foam nucleating agent) may be added for the purpose of adjusting the size of the foam cell. Examples of the foam control agent include inorganic powders such as talc, silicon dioxide, titanium dioxide, calcium carbonate, and sodium bicarbonate, and citric acid, a mixture of sodium bicarbonate and citric acid, and the like. It can also be used. The blending amount of the cell regulator varies depending on the desired physical properties of the foam, but is generally about 0.01 to 3 parts by weight based on 100 parts by weight of the propylene-based polymer composition. Except when it is included).

The expansion ratio of the pre-expanded particles obtained in the present invention is not particularly limited, but is preferably 1.1 to 70 times, more preferably 5 to 60 times. If the expansion ratio is less than 1.1 times, the cushioning properties and the lightness are insufficient, which is not preferable in terms of economy. If it exceeds 70 times, the bubble diameter becomes too large, becomes distorted and non-uniform, and the mechanical strength is undesirably reduced.

The cell diameter of the pre-expanded particles is 50 to 20.
00 μm is preferred, and more preferably 100 to 1000
μm. If the bubble diameter is less than 50 μm, the heat resistance and mechanical strength are insufficient, and if it exceeds 2000 μm, the buffer characteristics deteriorate, which is not preferable.

The closed cell ratio of the pre-expanded particles is 50%.
Or more, more preferably 70% or more. If the closed cell ratio is less than 50%, the secondary foaming property during in-mold molding,
The buffer characteristics and mechanical strength are insufficient, which is not preferable.

The pre-expanded particles obtained as described above can be subjected to internal pressure application as required after normal curing, filled in a molding die, and subjected to heat expansion molding.

[0080]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. Definitions of terms used in Examples and Comparative Examples and measurement methods are as follows. —Propylene polymer composition— Intrinsic viscosity [η]: The intrinsic viscosity was measured in tetralin at 135 ° C. using an Ostwald viscometer (manufactured by Mitsui Toatsu Chemicals, Inc.) (unit: dl / g). . Comonomer polymerization unit content in the propylene-based polymer composition: measured by ¹³ C-NMR method (F, manufactured by JEOL Ltd.
It was calculated from the area of each peak (using a T-NMR spectrometer) (unit:% by weight).

-Pre-expanded particles-Expansion ratio: The density of the propylene polymer composition was 0.90.
It was determined from the following formula: g / cm ³ : expansion ratio (unit: times) = 0.90 / density of pre-expanded particles (unit: g / cm ³ ). The density of the pre-expanded particles was calculated from the weight and the volume determined by the submersion method. Average cell diameter: The cross section of the pre-expanded particles was photographed with a microscope equipped with a camera, the cell diameter was measured, and the average value of the measured cell diameter was calculated (unit: mm). Cell diameter distribution: The cell diameter was measured by the method described above, and A was obtained and evaluated by the following formula: A = maximum cell diameter / average cell diameter. ：: A is less than 2.0, ×: A
-2.0 or more -In-mold foam molded article- Density: The individual densities obtained by dividing the molded article into 20 were calculated from the weight and the volume obtained by the submersion method, and the average value was obtained and defined as the density (unit: g. cm ³ ). Density distribution: The density was determined by the above method, and B was determined and evaluated by the following equation: B = (maximum density-minimum density) / average density. ：: B is less than 0.10, ×:
B: 0.10 or more Properties: The surface appearance of the molded product and the fusion property between particles were visually evaluated. ：: The surface is smooth and the particles are well fused with each other. ×: Surface sink and deformation are observed, and the fusibility between the particles is poor.

Example 1 (1) Preparation of Transition Metal Compound Catalyst Component Decane 3 was prepared in a stainless steel reactor equipped with a stirrer.
7.5 liters, 7.14 kg of anhydrous magnesium chloride,
And 35.1 liters of 2-ethyl-1-hexanol were mixed, and heated and reacted at 140 ° C. for 4 hours with stirring to obtain a uniform solution. 1.67 kg of phthalic anhydride was added to the homogeneous solution, and the mixture was further stirred and mixed at 130 ° C. for 1 hour to dissolve phthalic anhydride in the uniform solution. After cooling the obtained homogeneous solution to room temperature (23 ° C.),
This homogenous solution was maintained at -20 ° C with titanium tetrachloride 200.
The whole amount was dropped into the liter over 3 hours. After the dropwise addition, the temperature was raised to 110 ° C over 4 hours, and when the temperature reached 110 ° C, 5.03 liters of di-i-butyl phthalate was added.
The reaction was carried out by stirring at 10 ° C. for 2 hours. After the reaction,
The solid part was collected by hot filtration, and the solid part was resuspended with 275 liters of titanium tetrachloride.
The reaction lasted for hours. After the completion of the reaction, a solid portion was collected again by hot filtration, and sufficiently washed with n-hexane until no free titanium was detected in the washing solution. continue,
The solvent was separated by filtration, and the solid portion was dried under reduced pressure to obtain a titanium-containing supported catalyst component (transition metal compound catalyst component) containing 2.4% by weight of titanium.

(2) Preparation of Pre-Activated Catalyst After replacing a stainless steel reactor having an inner volume of 30 liters with inclined blades with nitrogen gas, 18 liters of n-hexane, 60 mmol of triethylaluminum, and a titanium-containing carrier prepared as described in the preceding paragraph were used. After adding 150 g of the catalyst component (75.16 mmol in terms of titanium atoms), propylene 500 was added.
g was supplied and prepolymerization was performed at -2 ° C for 40 minutes. Separately, as a result of analyzing the polymer formed after the prepolymerization performed under the same conditions, 3.0 g of polypropylene was formed per 1 g of the titanium-containing supported catalyst component, and the intrinsic viscosity [η _A ] of the polypropylene was 2.80 dl. / G.

After the completion of the reaction time, unreacted propylene was discharged to the outside of the reactor, and the gas phase of the reactor was replaced with nitrogen once. Then, while maintaining the temperature in the reactor at -1 ° C, the reaction was continued. Ethylene was continuously supplied to the reactor for 4 hours so as to maintain the pressure in the vessel at 0.59 MPa, and preactivation polymerization was performed. Separately, as a result of analyzing the polymer formed after the preactivation polymerization performed under the same conditions, 50.6 g of the polymer was present per 1 g of the titanium-containing supported catalyst component, and the intrinsic viscosity [η _T ] of the polymer was 30. It was 5 dl / g.

Produced by preactivated polymerization with ethylene
Amount of polyethylene per gram of supported catalyst component containing titanium
(W_B) Is a titanium-containing supported catalyst after pre-activation treatment
Amount of polymer produced per gram of component (W_T) And after prepolymerization
Of propylene per gram of supported titanium-containing catalyst component
Production (W_A) Is obtained by the following equation. W_B= W_T-W_A In addition, the polymer produced by pre-activated polymerization with ethylene
Intrinsic viscosity of styrene [η _B] Is the poly
Intrinsic viscosity of propylene [η_A] And pre-activation
Intrinsic viscosity [η_T] From the following equation
Can be [Η_B] = ([Η_T] X W_T− [Η_A] X W_A) / (W_T-W
_A)

After completion of the reaction time, unreacted ethylene was discharged to the outside of the reactor, and the gas phase of the reactor was replaced with nitrogen once to obtain a preactivated catalyst slurry for producing a propylene polymer composition. However, separately from the calculation results by the above formula using the data of the pre-polymerization with propylene and the pre-activation polymerization with ethylene performed under the same conditions, the amount of polyethylene produced by the pre-activation polymerization with ethylene is 47.6 g per 1 g of the component, and the intrinsic viscosity [η _B ] was 32.2 dl / g. .

(3) Production of Propylene Polymer Composition After replacing a stainless steel polymerization vessel having an internal volume of 500 liters with a stirrer with nitrogen, n-hexane 240
1 liter, 780 mmol of triethylaluminum, 130 mmol of diisopropyldimethoxysilane, and 4.5 g of a titanium-containing supported catalyst component of the preactivated catalyst slurry obtained above were charged into the polymerization reactor.
Subsequently, after the temperature was raised to 60 ° C., the hydrogen concentration ratio and the ethylene concentration ratio with respect to the propylene concentration were both set to 0.0.
3 so that the gas phase pressure in the polymerization vessel is 0.7
While maintaining 9 MPa, propylene, hydrogen and ethylene were continuously supplied into the polymerization reactor for 3 hours to carry out copolymerization of propylene / ethylene. After the polymerization time, 1 liter of methanol was introduced into the polymerization vessel, and the catalyst was deactivated at 60 ° C.
After the unreacted gas is discharged, the solvent is separated and the polymer is dried to obtain an intrinsic viscosity of 2.19 dl /
g, a polymer 4 having an ethylene polymerization unit content of 3.4% by weight
3.2 kg were obtained. The obtained polymer is a propylene-based polymer composition having a polyethylene content of 0.50% by weight corresponding to the component (b) produced by the preactivation treatment, and a propylene / ethylene random copolymer corresponding to the component (a). The intrinsic viscosity of the polymer was 2.04 dl / g, and the content of ethylene polymerization units was 2.9% by weight.

(4) Production of Pre-expanded Particles 100 parts by weight of the propylene-based polymer composition and tetrakis [methylene-3- (3′-5′-di-tert-butyl-
4'-hydroxyphenyl) propionate] 0.3 parts by weight, 1,1,3-tris (2-methyl-5-t-butyl-4-hydroxyphenyl) butane 0.1 part by weight, tris (2,4- 0.01 part by weight of di-t-butylphenyl) phosphite and 0.1 part by weight of calcium stearate are mixed, and then a pellet-shaped resin composition A is formed using a granulator having a cylinder setting temperature of 230 ° C. and a screw diameter of 40 mm. I got

The resin composition A in the form of pellets was processed into pre-expanded particles by the following method. Table 1 shows the properties of the obtained pre-expanded particles. A 40 mmφ extruder (single screw extruder, L / D ratio 32) and a 50 mmφ extruder (single screw extruder, L / D ratio 2) having a barrel hole for blowing agent injection in the middle of the barrel
6), the resin composition A10
0 parts by weight of talc (average particle size 8μ)
m) in a proportion of 0.5 parts by weight was added to 15 kg /
At the time, butane is injected at 2.1 kg / hour as a foaming agent from a barrel hole of the 40 mmφ extruder at a rate of 2.1 kg / hour and melt-mixed. The temperature was adjusted so that the resin temperature would be reached, and then the foamed strand was extruded from a porous die (hole diameter: 1 mmφ, number of holes: 24) attached to the tip of a 50 mmφ extruder, and a rotary blade was brought into contact with the porous die and rotated. The foamed strand was cut by a strand cutter having the same to produce pre-expanded particles. The temperature of the 40 mmφ extruder is 235 ° C. in one zone, 205 ° C. in two zones, 185 ° C. in three zones, 185 ° C. in four zones, and the temperature of the extruder in one zone is 143 ° C. in one zone, 138 ° C. in two zones, three to five zones.
Zone 133 ° C., extruded resin temperature was 135 ° C. (extruded resin temperature was measured at a breaker plate section provided between a 50 mmφ extruder and a perforated die).

(5) Production of In-Mold Expanded Molded Product After maintaining the pre-expanded particles in a nitrogen pressurized atmosphere of 0.7 MPa for 1 day, the pre-expanded particles were filled in a molding die and heated with steam at 145 ° C. for 40 seconds. And processed into an in-mold foam molded article. Table 1 shows the properties of the obtained in-mold foam molded article.

(Example 2) (1) Preparation of transition metal compound catalyst component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of pre-activated catalyst A pre-activated catalyst slurry was obtained under the same conditions as in Example 1. (3) Production of propylene-based polymer composition A propylene-based polymer composition was produced under the same conditions as in Example 1 except that the hydrogen concentration ratio to the propylene concentration was changed to 0.04, and the intrinsic viscosity was measured. 2.05 g / dl,
Polymer having an ethylene polymerized unit content of 3.4% by weight
3 kg were obtained. The obtained polymer is a propylene-based polymer composition having a polyethylene content of 0.48% by weight corresponding to the component (b) produced by the preactivation treatment,
The intrinsic viscosity of the propylene / ethylene random copolymer corresponding to the component (a) was 1.90 g / dl, and the ethylene polymerization unit content was 2.9% by weight. (4) Production of Pre-expanded Particles A pellet-shaped resin composition A was obtained under the same conditions as in Example 1, and processed into pre-expanded particles under the same conditions as in Example 1. Table 1 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were processed into an in-mold expanded molded article under the same conditions as in Example 1. Table 1 shows the properties of the obtained in-mold foam molded article.

Comparative Example 1 (1) Preparation of Transition Metal Compound Catalyst Component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of preactivated catalyst The procedure was carried out except that the amount of polyethylene produced per gram of the transition metal compound catalyst component was changed from 47.6 g to 0.07 g by changing the conditions of the preactivated polymerization with ethylene. Under the same conditions as in Example 1, a preactivated catalyst slurry was obtained. (3) Production of Propylene Polymer Composition Under the same conditions as in Example 1, a polymer having an intrinsic viscosity of 2.04 dl / g and an ethylene polymerization unit content of 2.9% by weight was obtained.
The obtained polymer had a polyethylene content of 0.000 corresponding to the component (b) produced by the preactivation treatment.
73% by weight of a propylene polymer composition, wherein (a)
The intrinsic viscosity of the propylene / ethylene random copolymer corresponding to the component was 2.04 dl / g, and the ethylene polymerization unit content was 2.9% by weight.

(4) Production of Pre-expanded Particles A pellet-shaped resin composition A was obtained under the same conditions as in Example 1. Except that this resin composition A was changed such that the temperature of the 50 mmφ extruder was the lowest resin temperature (described in Table 1) at which the surface of the foamed particles did not have irregularities in the range of 130 to 150 ° C. In the same manner as in Example 1, it was processed into pre-expanded particles. Table 1 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were processed into an in-mold expanded molded article under the same conditions as in Example 1. Table 1 shows the properties of the obtained in-mold foam molded article.

Comparative Example 2 (1) Preparation of Transition Metal Compound Catalyst Component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of pre-activated catalyst Under the same conditions as in Comparative Example 1, a pre-activated catalyst slurry was obtained. (3) Production of propylene-based polymer composition Under the same conditions as in Example 2, a polymer having an intrinsic viscosity of 1.90 dl / g and an ethylene polymerization unit content of 2.9% by weight was obtained.
The obtained polymer had a polyethylene content of 0.000 corresponding to the component (b) produced by the preactivation treatment.
71% by weight of a propylene polymer composition, wherein (a)
The intrinsic viscosity of the propylene / ethylene random copolymer corresponding to the component was 1.90 dl / g, and the ethylene polymerization unit content was 2.9% by weight.

(4) Production of Pre-expanded Particles A pellet-shaped resin composition A was obtained under the same conditions as in Example 1. Except that this resin composition A was changed such that the temperature of the 50 mmφ extruder was the lowest resin temperature (described in Table 1) at which the surface of the foamed particles did not have irregularities in the range of 130 to 150 ° C. In the same manner as in Example 1, it was processed into pre-expanded particles. Table 1 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were processed into an in-mold expanded molded article under the same conditions as in Example 1. Table 1 shows the properties of the obtained in-mold foam molded article.

[0096]

[Table 1]

Example 3 (1) Preparation of Transition Metal Compound Catalyst Component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of Preactivated Catalyst A preactivated catalyst slurry was obtained under the same conditions as in Example 1. (3) Production of Propylene Polymer Composition The comonomer was changed from ethylene to 1-butene, the hydrogen concentration ratio and the 1-butene concentration ratio to the propylene concentration were changed to 0.035 and 0.05, and the polymerization time was reduced to 3.5 hours. A propylene-based polymer composition was produced under the same conditions as in Example 1 except for the change, and the intrinsic viscosity was 2.03 g /
40.6 g of a polymer having a dl and 1-butene polymerization unit content of 5.8% by weight was obtained. The obtained polymer is a propylene-based polymer composition having a polyethylene content of 0.53% by weight and produced by the preactivation treatment corresponding to the component (b), and the propylene / 1-butene random corresponding to the component (a). The intrinsic viscosity of the copolymer was 1.87 dl / g, and the content of 1-butene polymerized unit was 5.8% by weight.

(4) Production of Pre-Expanded Particles A pellet-shaped resin composition A was obtained under the same conditions as in Example 1. The butane injection amount of this resin composition A was 1.8 kg.
/ Hour, and change the temperature of the 50 mmφ extruder from 130 to 150
The pre-expanded particles were processed in the same manner as in Example 1 except that the resin temperature was changed so that the surface of the expanded particles did not have irregularities in the range of ° C. (described in Table 2). Table 2 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were processed into an in-mold expanded molded article under the same conditions as in Example 1. Table 2 shows the properties of the obtained in-mold foam molded article.

(Example 4) (1) Preparation of transition metal compound catalyst component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of Preactivated Catalyst A preactivated catalyst slurry was obtained under the same conditions as in Example 1. (3) Production of propylene-based polymer composition Using ethylene and 1-butene as comonomer, hydrogen concentration ratio to propylene concentration, ethylene concentration ratio and 1
-Butene concentration ratios of 0.04, 0.025 and 0.03
The propylene polymer composition was manufactured under the same conditions as in Example 1 except that the intrinsic viscosity was changed to 2.08.
g / dl, ethylene polymerized unit content 2.9% by weight, 1-
Polymer 41.9 having a butene polymerization unit content of 3.9% by weight
g was obtained. The obtained polymer had a polyethylene content of 0.1% by preactivation treatment corresponding to the component (b).
51% by weight of a propylene polymer composition, wherein (a)
The propylene / ethylene / 1-butene random copolymer corresponding to the component has an intrinsic viscosity of 1.93 dl / g, an ethylene polymerization unit content of 2.4% by weight, and a 1-butene polymerization unit content of 3.9% by weight. Met

(4) Production of Pre-Expanded Particles A pellet-shaped resin composition A was obtained under the same conditions as in Example 1. This resin composition A was charged with a butane injection amount of 1.5 kg.
/ Hour, and change the temperature of the 50 mmφ extruder from 130 to 150
The pre-expanded particles were processed in the same manner as in Example 1 except that the resin temperature was changed so that the surface of the expanded particles did not have irregularities in the range of ° C. (described in Table 2). Table 2 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were formed into an in-mold expanded molded article in the same manner as in Example 1 except that the temperature of steam was changed to 140 ° C. and the heating time was changed to 30 seconds. processed. Table 2 shows the properties of the obtained in-mold foam molded article.

Comparative Example 3 (1) Preparation of Transition Metal Compound Catalyst Component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of Preactivated Catalyst Under the same conditions as in Comparative Example 1, a preactivated catalyst slurry was obtained. (3) Production of propylene-based polymer composition A propylene-based polymer composition was produced under the same conditions as in Example 3, and had an intrinsic viscosity of 1.87 dl / g and a 1-butene polymerization unit content of 5.8% by weight. Was obtained. The obtained polymer was a propylene-based polymer composition having a polyethylene content of 0.00078% by weight, which was produced by the preactivation treatment corresponding to the component (b), and the propylene / 1-component corresponding to the component (a). The intrinsic viscosity of the butene random copolymer is 1.87 dl / g, and the 1-butene polymerization unit content is 5.87 dl / g.
It was 8% by weight.

(4) Production of Pre-Expanded Particles A pellet-shaped resin composition A was obtained under the same conditions as in Example 1. The butane injection amount of this resin composition A was 1.8 kg.
/ Hour, and change the temperature of the 50 mmφ extruder from 130 to 150
The pre-expanded particles were processed in the same manner as in Example 1 except that the resin temperature was changed so that the surface of the expanded particles did not have irregularities in the range of ° C. (described in Table 2). Table 2 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Molded Article Under the same conditions as in Example 1, it was processed into an in-mold foam molded article.
Table 2 shows the properties of the obtained in-mold foam molded article.

Comparative Example 4 (1) Preparation of Transition Metal Compound Catalyst Component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of pre-activated catalyst Under the same conditions as in Comparative Example 1, a pre-activated catalyst slurry was obtained. (3) Production of propylene-based polymer composition A propylene-based polymer composition was produced under the same conditions as in Example 4, and had an intrinsic viscosity of 1.93 dl / g, an ethylene polymerization unit content of 2.4% by weight, and -Butene polymerized unit content 3.
9% by weight of the polymer was obtained. The resulting polymer is (b)
It is a propylene-based polymer composition having a content of 0.00075% by weight of polyethylene produced by the preactivation treatment corresponding to the component. The intrinsic viscosity of the polypropylene corresponding to the component (a) is 1.93 dl / g, The polymerization unit content is 2.4% by weight, and the 1-butene polymerization unit content is 3.9.
% By weight.

(4) Production of Pre-expanded Particles A pellet-shaped resin composition A was obtained under the same conditions as in Example 1. This resin composition A was charged with a butane injection amount of 1.5 kg.
/ Hour, and change the temperature of the 50 mmφ extruder from 130 to 150
The pre-expanded particles were processed in the same manner as in Example 1 except that the resin temperature was changed so that the surface of the expanded particles did not have irregularities in the range of ° C. (described in Table 2). Table 2 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were formed into an in-mold expanded molded article in the same manner as in Example 1 except that the temperature of steam was changed to 140 ° C. and the heating time was changed to 30 seconds. processed. Table 2 shows the properties of the obtained in-mold foam molded article.

[0105]

[Table 2]

(Example 5) (1) Preparation of transition metal compound catalyst component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of preactivated catalyst The procedure was carried out except that the conditions of the preactivated polymerization with ethylene were changed to change the amount of polyethylene produced per gram of the transition metal compound catalyst component from 47.6 g to 71.6 g. Under the same conditions as in Example 1, a preactivated catalyst slurry was obtained.

(3) Production of Propylene Polymer Composition In a continuous horizontal gas phase polymerizer (length / diameter = 3.7) equipped with a stirrer having an internal volume of 110 liters and purged with nitrogen, polypropylene powder was added. 25 kg of the preactivated catalyst slurry as a titanium-containing supported catalyst component, and 0.62 g / h of triethylaluminum and diisopropyldimethoxysilane with respect to titanium atoms in the titanium-containing supported catalyst component. 90 and 15 were continuously supplied. Further, under the condition of a polymerization temperature of 70 ° C., hydrogen was added so that the ratio of the hydrogen concentration in the polymerization vessel to the propylene concentration was 0.0055, and propylene was further added so that the pressure in the polymerization vessel was maintained at 2.15 MPa. The mixture was supplied into a polymerization vessel to continuously perform propylene gas phase polymerization for 150 hours. During the polymerization period, the polymer was withdrawn at a rate of 11 kg / h from the polymerization vessel so that the level of the polymer held in the polymerization vessel was maintained at 60% by volume. The extracted polymer was subjected to a contact treatment at 100 ° C. for 30 minutes with a nitrogen gas containing 5% by volume of water vapor to obtain a polymer having an intrinsic viscosity of 1.98 dl / g. The obtained polymer is a propylene-based polymer composition having a polyethylene content of 0.40% by weight produced by the preactivation treatment corresponding to the component (b), and the intrinsic viscosity of the polypropylene corresponding to the component (a) is It was 1.86 dl / g.

(4) Preparation of pre-expanded particles 100 parts by weight of the propylene polymer composition was added to tetrakis [methylene-3- (3′-5′-di-t-butyl-4′-hydroxyphenyl) propionate. ] 0.
3 parts by weight, 1,1,3-tris (2-methyl-5-t-
Butyl-4-hydroxyphenyl) butane 0.1 part by weight, tris (2,4-di-t-butylphenyl) phosphite 0.01 part by weight, calcium stearate 0.1 part by weight.
1 part by weight, 1-butene polymer [MFR (measured at 190 ° C.)
4.0 g / 10 min, density 0.900 g / cm ³ , melting point 1
[04 ° C.], 10 parts by weight, and then pelletized resin composition A using a granulator having a cylinder set temperature of 230 ° C. and a screw diameter of 40 mm. This resin composition A is
The butane injection rate was changed to 1.8 kg / hour, and the temperature of the 50 mmφ extruder was changed in the range of 150 to 160 ° C. so as to become the lowest resin temperature (described in Table 3) at which unevenness does not occur on the surface of the foamed particles. Except for the above, it was processed into pre-expanded particles in the same manner as in Example 1. Table 3 shows the properties of the obtained pre-expanded particles.

(5) Production of In-Mold Expanded Molded Article The pre-expanded particles were subjected to in-mold foam molding in the same manner as in Example 1 except that the temperature of steam was changed to 153 ° C. and the heating time was changed to 45 seconds. It was processed into a compact. Table 3 shows the properties of the obtained in-mold foam molded article.

(Example 6) (1) Preparation of transition metal compound catalyst component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of pre-activated catalyst A pre-activated catalyst slurry was obtained under the same conditions as in Example 1. (3) Production of propylene-based polymer composition A propylene-based polymer composition was obtained under the same conditions as in Example 1.

(4) Production of pre-expanded particles 1-butene polymer was converted to low-density polyethylene [MFR (19
0 ° C) 7.0 g / 10 min, density 0.919 g / cm
Except having changed to ³ ], it carried out similarly to Example 5, and obtained the resin composition A of the pellet form. This resin composition A is
The butane injection rate was changed to 1.8 kg / hour, and the temperature of the 50 mmφ extruder was changed in the range of 130 to 150 ° C. so that the lowest resin temperature at which the surface of the foamed particles did not have irregularities (described in Table 3). Except for the above, it was processed into pre-expanded particles in the same manner as in Example 1. Table 3 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were processed into an in-mold expanded molded article under the same conditions as in Example 1. Table 3 shows the properties of the obtained in-mold foam molded article.

Comparative Example 5 (1) Preparation of Transition Metal Compound Catalyst Component Under the same conditions as in Example 1, a titanium-containing supported catalyst component was obtained. (2) Preparation of pre-activated catalyst A pre-activated catalyst slurry was obtained under the same conditions as in Comparative Example 2. (3) Production of propylene-based polymer composition A propylene-based polymer composition was obtained under the same conditions as in Comparative Example 1.

(4) Preparation of Pre-expanded Particles A pellet-shaped resin composition A was obtained in the same manner as in Example 6. This resin composition A was added at a butane injection rate of 1.8 kg /
Change the temperature of the extruder 50mmφ 130-150 ° C
Was processed into pre-expanded particles in the same manner as in Example 1 except that the resin temperature was changed so that the surface of the expanded particles did not have irregularities in the range (listed in Table 3). Table 3 shows the properties of the obtained pre-expanded particles. (5) Production of In-Mold Expanded Molded Article The pre-expanded particles were processed into an in-mold expanded molded article under the same conditions as in Example 1. Table 3 shows the properties of the obtained in-mold foam molded article.

[0114]

[Table 3]

[0115]

According to the present invention, pre-expanded particles having a uniform expansion ratio and a uniform cell diameter without coarse cells due to open cells can be obtained. By the pre-expanded particles, a foam molded article excellent in cushioning properties, heat insulation properties, mechanical strength, and the like, and particularly suitably used as a cushioning material, a heat insulating material, a packaging material, and the like is obtained. In addition, since this manufacturing method and process are simplified in a continuous manner, there is no need for a large-sized facility as in the past, or a special post-treatment facility such as electron beam irradiation, and the productivity and economy are excellent. I have.

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[Procedure amendment]

[Submission date] January 28, 2000 (2000.1.2
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Change

[Correction contents]

In the present invention, not only the propylene polymer composition can be used alone, but also other resins can be mixed with the propylene polymer composition.
As another resin, the propylene polymer composition of the present invention
Other than propylene polymers, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, linear ultra low density polyethylene, ethylene
Ethylene resin such as vinyl acetate copolymer, syndiotactic polypropylene, butene resin, cyclic olefin resin, petroleum resin, styrene resin, acrylic resin,
Fluorine resin, ethylene / propylene rubber, ethylene /
Butene rubber , ethylene / hexene rubber , ethylene / octane
Thermosoftening resins such as ethylene / higher olefin rubber such as ten rubber can be used, and not only one kind but also two or more kinds can be used. The blending amount is propylene polymer composition 1.
A maximum of about 50 parts by weight is preferable for 00 parts by weight.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction contents]

Further, in addition to the above-mentioned components, the propylene-based polymer composition of the present invention may contain, as stabilizers, antioxidants, neutralizers, weathering agents, ultraviolet absorbers, and other additives such as antistatic agents. , Lubricants, flame retardants, colorants, and talc,
Inorganic fillers such as calcium carbonate or organic fillers (eg
For example, wood flour, pulp, waste paper, synthetic paper, natural fibers, synthetic fibers
And the like can be blended in a range that does not impair the purpose of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) // (C08L 23/10 23:04) F term (Reference) 4F074 AA17 AA18 AA19 AA20 AA24 AB01 AB05 BA03 BA13 BA16 BA20 BA32. BC16B BC17B BC19B BC24B BC25B CA15A CA16A CA47C CB23C CB24C CB25C CB27C CB43C CB44C CB52C CB53C CB54C CB55C CB63C CB64C CB66 DACB 07 DA CB CB88 DA CB81C CB81C CB81C CB81C CB83C

Claims (3)

[Claims] 1. A resin composition containing a propylene-based polymer composition containing the following (a) and (b) as main components and a foaming agent are melt-kneaded at a high temperature and a high pressure by an extruder, and then the pressure is released. A method for producing pre-expanded particles, comprising extruding from an extruder to form expanded strands, and then cutting the expanded strands to form expanded beads. (A) a propylene homopolymer or a propylene-olefin copolymer containing 50% by weight or more of propylene polymerized units having an intrinsic viscosity of 0.2 to 10 dl / g measured in tetralin at 135 ° C. (collectively, , "Propylene (co) polymer"). (B) An ethylene homopolymer or ethylene polymer unit having an intrinsic viscosity of 15 to 100 dl / g measured in tetralin at 135 ° C. per 100 parts by weight of the component (a)
0.01 to 5.0 parts by weight of an ethylene-olefin copolymer containing 0% by weight or more (collectively referred to as "ethylene (co) polymer"). 2. The periodic table (1991 edition), Group 1 or 2, wherein the propylene-based polymer composition has a transition metal compound catalyst component of 0.01 to 1000 mol per mol of transition metal atom.
A catalyst for the production of a polyolefin comprising a combination of an organometallic compound of a metal selected from the group consisting of metals belonging to Group 12, Group 12 and Group 13 and 0 to 500 moles of an electron donor per mole of a transition metal atom; 2. Polymerization of propylene alone or propylene and an olefin other than propylene in the presence of a preactivated catalyst containing the ethylene (co) polymer as the component (b) according to claim 1 supported on the catalyst. 2. The method for producing pre-expanded particles according to claim 1, wherein the propylene (co) polymer of the component (a) is produced by copolymerizing (a). 3. The foaming agent is one or more compounds selected from the group consisting of hydrocarbons having a boiling point of -50 to 100 ° C., halogenated hydrocarbons having a boiling point of -50 to 100 ° C., and inorganic gases. The method for producing pre-expanded particles according to claim 1.