JP2002275324A - Polypropylene resin composition particles, modified polypropylene resin composition using the particles, foam comprising the composition, and method for producing the same - Google Patents

Abstract

(57) [Summary] (Modifications) [Problem] A modified polypropylene resin composition having an improved foaming property capable of preparing a foam having a high closed cell rate, and a polypropylene resin composition particle used as a raw material of the composition. I will provide a. A high-molecular-weight polyethylene (A) having an intrinsic viscosity [η] of 20 to 100 dl / g measured at 135 ° C. in tetralin and an intrinsic viscosity [η] measured at 135 ° C. of tetralin are used. Are polypropylene resin composition particles comprising 70 to 99.5 parts by weight of 4.0 to 12 dl / g, and the content of the particles through a 200 mesh by a standard sieve is 1% or less. And a 20-mesh residue of 5% or less. A blend of 100 parts by weight of the polypropylene resin composition particles and 0.01 to 5 parts by weight of a radical initiator (C) is mixed with 150 to 30 parts by weight of the mixture.
A modified polypropylene resin composition obtained by melt-kneading at 0 ° C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polypropylene resin composition particles, a modified polypropylene resin composition using the particles, a foam comprising the composition, and a method for producing the same. The present invention relates to a polypropylene resin composition particle capable of preparing a modified polypropylene resin composition, a modified polypropylene resin composition, a foam comprising the composition, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Foams made of thermoplastic resin are:
Generally, it is widely used as a heat insulating material, a cushioning material, a core material, a food container and the like because it is lightweight and has good heat insulating properties and good buffering property against external stress. In particular, polystyrene foam is conventionally used for trays for fresh foods, processed foods, and cups for cup ramen. However, polystyrene foams have recently been studied for alternatives to other resins due to environmental concerns. Above all, foams made of polypropylene resin have good chemical resistance, impact resistance and heat resistance, are excellent in food hygiene, and are easy to incinerate waste. The use as a tray is under consideration.

[0003] However, polypropylene resins are
Because it is a crystalline resin, the viscosity and melt tension at the time of melting are low, and there is no sudden increase in viscosity at the time of elongation deformation.When foaming this polypropylene resin, the expansion ratio is low, There was a problem that it was easily destroyed. For this reason, when the polypropylene-based resin is foamed, it has high closed-cell properties and excellent appearance,
It was difficult to obtain a low-density foam having excellent secondary workability. In addition, drawdown (sagging) when secondary processing by heating and softening a sheet of polypropylene resin
There was a problem that would occur.

As a method for improving the foaming property of a polypropylene resin, for example, as proposed in Japanese Patent Application Laid-Open No. Sho 61-152754, a foaming agent and a crosslinking assistant are added to a polypropylene resin to reduce the molecular weight. It has been attempted to increase the melt tension by cross-linking.
However, in this method, the melt tension of the polypropylene resin is not sufficiently improved or the viscosity during elongation deformation is insufficient, and a cross-linking aid that does not crosslink remains in such a polypropylene resin, resulting in a strong odor. Not suitable for food packaging applications.

A method of blending polyethylene with a polypropylene resin and foaming the blend has been proposed in Japanese Patent Publication No. 44-2574. However, in such a method, the effect of improving the melt tension of the polypropylene resin is small, and a foam excellent in secondary workability cannot be obtained. Further, Japanese Patent Laid-Open No. 10-2
No. 92069 describes that the melt tension is improved by melt-kneading a polypropylene (co) polymer containing a high-molecular-weight polyethylene and a radical initiator. However, this publication proposes only the result of improved melt tension, and what kind of state of polymerized particles is required to obtain a resin having characteristics suitable for foam molding. No suggestion is made. This publication does not describe anything about improving the drawdown property of the polypropylene resin.

The inventors of the present application have made intensive studies to solve the above problems, and have obtained polypropylene resin compositions having different melt tensions depending on the particle size distribution of the polypropylene resin composition particles containing high molecular weight polyethylene. When the polypropylene resin composition particles have a specific particle size distribution, the effect of improving the melt tension appears remarkably, and the production of a modified polypropylene resin composition using the polypropylene resin composition particles in a plant is easy. And completed the present invention.

[0007]

SUMMARY OF THE INVENTION The first object of the present invention is to solve the problems associated with the prior art as described above, and has an improved foaming property capable of preparing a foam having a high closed cell rate. It is another object of the present invention to provide a modified polypropylene resin composition, polypropylene resin composition particles as a raw material of the composition, a foam comprising the modified polypropylene resin composition, and a method for producing the same.

A second object of the present invention is to provide a modified polypropylene resin composition having high rigidity and excellent food hygiene properties, suitable for food trays and the like, and suitable for foam molding. A third object of the present invention is to provide a foam having excellent heat resistance, a high expansion ratio, a low density and a beautiful appearance, and a method for producing the same. A fourth object of the present invention is to provide a foam having improved drawdown properties and excellent secondary workability, and a method for producing the same.

[0009] A fifth object of the present invention is to provide a modified polypropylene resin composition having less trouble during production in a plant.

[0010]

SUMMARY OF THE INVENTION The polypropylene resin composition particles according to the present invention comprise 0.5 to 30 parts by weight of a high molecular weight polyethylene (A) having an intrinsic viscosity [η] of 20 to 100 dl / g measured at 135 ° C. in tetralin. Intrinsic viscosity [η] measured in tetralin at 135 ° C. is 4.0 to 12 dl / g
70 to 99.5 parts by weight of polypropylene (B) [the total amount of the component (A) and the component (B) is 100 parts by weight].
The particles are characterized in that 200% mesh passing through a standard sieve according to JIS Z8801 is 1% or less, and 20 mesh residue is 5% or less.

It is preferable that the high molecular weight polyethylene (A) is produced by prepolymerization at the time of producing the polypropylene (B). The polypropylene resin composition particles are preferably produced using a solid titanium catalyst component (a) prepared by contacting a liquid magnesium compound and a titanium compound.

The modified polypropylene resin composition according to the present invention comprises 100 parts by weight of the above-described polypropylene resin composition particles according to the present invention and 0.01 to 5 radical initiators (C).
It is characterized by being obtained by melt-kneading a blend with parts by weight at 150 to 300 ° C. The radical initiator (C) is preferably 2,5-dimethyl-2,5-di # (t-butylperoxy) hexane.

A foam according to the present invention is characterized by comprising the above-mentioned modified polypropylene resin composition according to the present invention. In the method for producing a foam according to the present invention, the above-mentioned mixture comprising the modified polypropylene resin composition according to the present invention and an organic blowing agent (D) and / or an inorganic blowing agent (E) is heated by an extruder. It is characterized in that it is extruded after melt-kneading and foamed.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The polypropylene resin composition particles according to the present invention, a modified polypropylene resin composition using the particles, a foam comprising the composition, and a method for producing the same will be specifically described below. First, among the raw materials of the modified polypropylene resin composition according to the present invention, the polypropylene resin composition particles according to the present invention, which are used as main components, will be described.

Polypropylene Resin Composition Particles The polypropylene resin composition particles according to the present invention are particles of polypropylene (B) containing a small amount of high molecular weight polyethylene (A). [High-Molecular-Weight Polyethylene (A)] The high-molecular-weight polyethylene (A) used in the present invention is an ethylene homopolymer or an ethylene / α-olefin copolymer obtained by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms. It is a polymer.

Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,
Examples thereof include 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.
Among them, α-olefins having 3 to 8 carbon atoms are preferred. These α-olefins can be used alone or in combination of two or more.

These α-olefins may form a random copolymer with ethylene, or may form a block copolymer. High molecular weight polyethylene (A)
Represents a structural unit derived from these α-olefins as 1
It may be contained in a proportion of 0 mol% or less, preferably 5% or less. The high molecular weight polyethylene (A) may contain a small amount of unsaturated α-olefin in addition to the above α-olefin.

Specific examples of such unsaturated α-olefins include 1,3-butadiene, 1,3-pentadiene,
1,4-pentadiene, 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 4-methyl-1,4-hexadiene,
5-methyl-1,4-hexadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 6-ethyl-1,6-octadiene, 6-propyl-1,6-octadiene, 6-butyl
-1,6-octadiene, 6-methyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7-
Ethyl-1,6-nonadiene, 6-methyl-1,6-decadiene,
7-methyl-1,6-decadiene, 6-methyl-1,6-undecadiene, 1,7-octadiene, 1,9-decadiene, isoprene, butadiene, ethylidene norbornene, vinyl norbornene, dicyclopentadiene, and other carbon atoms 4
To 20 diene compounds.

The high molecular weight polyethylene (A) contains 2 mol% of structural units derived from these unsaturated α-olefins.
Below, preferably, it may be contained in a proportion of 1% mol or less. High molecular weight polyethylene (A) used in the present invention
Has an intrinsic viscosity [η] measured in tetralin of 135 ° C. of 20 to 100 dl / g, preferably 25 to 60 dl / g.
g, more preferably in the range of 35 to 45 dl / g. In the present invention, the intrinsic viscosity [η] is 20 to 10
High molecular weight polyethylene (A) in the range of 0 dl / g
When the polypropylene resin composition particles prepared using the above are melt-mixed with the radical initiator (C), a melt tension effective for foaming is obtained, and a good appearance is obtained without generating a gel component. A foamed sheet can be obtained.

In producing the polypropylene resin composition particles according to the present invention, the high molecular weight polyethylene (A) is used in an amount of 0.5 to 0.5 parts by weight based on 100 parts by weight of the total amount of the high molecular weight polyethylene (A) and the polypropylene (B). It is used in a proportion of 30 parts by weight, preferably 5 to 20 parts by weight, more preferably 5 to 10 parts by weight. High molecular weight polyethylene (A)
Is used in a proportion within the above range, it is possible to obtain polypropylene resin composition particles having excellent fluidity and good foam stability after foam molding.

[Polypropylene (B)] The polypropylene (B) used in the present invention is a propylene homopolymer,
Or a propylene / α-olefin copolymer obtained by copolymerizing propylene with ethylene and / or an α-olefin having 4 to 20 carbon atoms. 4 to 2 carbon atoms
As the α-olefin of 0, specifically, 1-butene,
Examples thereof include 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. As the α-olefin to be copolymerized with propylene, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable. These α-olefins can be used alone or in combination of two or more.

These α-olefins may form a random copolymer with propylene, or may form a block copolymer. The polypropylene (B) may contain structural units derived from these α-olefins in a proportion of 5% or less, preferably 2% or less. The polypropylene (B) used in the present invention preferably has an intrinsic viscosity [η] measured in tetralin at 135 ° C. of preferably 4.
0 to 12 dl / g, more preferably 5.0 to 10 dl
/ G. In the present invention, when the polypropylene resin composition particles prepared using the polypropylene (B) having the intrinsic viscosity [η] in the range of 4.0 to 12 dl / g are melt-mixed with the radical initiator (C). Since the resulting modified polypropylene resin composition has an appropriate melt flow rate (MFR),
The drawdown property during foam molding can be suppressed, and the foam of the modified polypropylene resin composition can be industrially easily produced.

In producing the polypropylene resin composition particles according to the present invention, the polypropylene (B) is used in an amount of 70 to 99.5 parts by weight based on 100 parts by weight of the total of the high molecular weight polyethylene (A) and the polypropylene (B). Parts, preferably 80 to 95 parts by weight, more preferably 90 to 95 parts by weight. When the polypropylene (B) is used in a proportion within the above range, a low-density foam having high closed-cell properties and excellent appearance and secondary workability (for example, vacuum moldability) can be obtained from the obtained polypropylene resin composition particles. It becomes possible to mold.

[Polypropylene Resin Composition Particles] The polypropylene resin composition particles according to the present invention are used for producing the polypropylene (B) when producing high molecular weight polyethylene (B).
Is preferably produced by prepolymerizing For example, the polypropylene resin composition particles according to the present invention include (a) a solid titanium catalyst component containing magnesium, titanium, halogen and an electron donor as essential components, (b) an organoaluminum compound catalyst component,
And (c) preparing a high molecular weight polyethylene (B) by prepolymerization using an olefin polymerization catalyst comprising an electron donor catalyst component, then preparing a polypropylene (B), and preparing the obtained polypropylene resin composition. It can be obtained by granulating.

In the present invention, the polypropylene resin composition particles are prepared using a solid catalyst prepared by contacting a liquid magnesium compound having a reducing property or a non-reducing property with a titanium compound. Preferably, it is Examples of the reducing magnesium compound include a magnesium compound having a magnesium-carbon bond or a magnesium-hydrogen bond.

Specific examples of such reducing magnesium compounds include dimethyl magnesium, diethyl magnesium, dipropyl magnesium, dibutyl magnesium, diamil magnesium, dihexyl magnesium, didecyl magnesium, ethyl magnesium chloride, propyl chloride. Examples include magnesium, butyl magnesium chloride, hexyl magnesium chloride, amyl magnesium chloride, butyl ethoxy magnesium, ethyl butyl magnesium, butyl magnesium hydride, and the like. These magnesium compounds alone,
Alternatively, two or more kinds can be used in combination. In addition, these magnesium compounds may form a complex compound with an organometallic compound described later.

Specific examples of the non-reducing magnesium compound include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide and magnesium fluoride; methoxy magnesium chloride, ethoxy magnesium chloride, and isopropoxy magnesium chloride. Alkoxy magnesium halides such as butoxymagnesium chloride and octoxymagnesium chloride; aryloxymagnesium halides such as phenoxymagnesium chloride and methylphenoxymagnesium chloride; ethoxymagnesium, isopropoxymagnesium, butoxymagnesium, n-octoxymagnesium and 2-ethylhexoxy Alkoxymagnesium such as magnesium; aryloxymers such as phenoxymagnesium and dimethylphenoxymagnesium Gnesium; magnesium carboxylate such as magnesium laurate and magnesium stearate; These magnesium compounds can be used alone or in combination of two or more.

Among the above-mentioned magnesium compounds, magnesium compounds having no reducing property are preferable, and among them, halogen-containing magnesium compounds are more preferable, and magnesium chloride, alkoxymagnesium chloride,
Allyloxymagnesium chloride is particularly preferred. Specific examples of the titanium compound include a tetravalent titanium compound represented by the following formula.

Ti (OR)_gX_4-g (Wherein, R is a hydrocarbon group, X is a halogen atom
And g is 0 ≦ g ≦ 4. ) Such titanium compound
As a product, specifically, TiCl_Four, TiBr_Four, TiI_Fouretc
Of titanium tetrahalide; Ti (OCH_Three) Cl_Three, Ti (O
C_TwoH_Five) Cl_Three, Ti (On-C_FourH₉) Cl_Three, Ti (OC_TwoH _Five) B
r_Three, Ti (O-iso-C_FourH₉) Br_ThreeTrihalogenated alcohols such as
Xtitanium; Ti (OCH_Three)_TwoCl_Two, Ti (OC_TwoH_Five)_TwoC
l_Two, Ti (On-C_FourH₉)_TwoCl_Two, Ti (OC _TwoH_Five)_TwoBr_TwoEtc.
Dialkoxytitanium dihalide; Ti (OCH_Three)_ThreeCl,
Ti (OC_TwoH_Five)_ThreeCl, Ti (On-C_FourH₉)_ThreeCl, Ti (OC_Two
H _Five)_ThreeMonohalogenated trialkoxy titanium such as Br; T
i (OCH_Three)_Four, Ti (OC_TwoH_Five)_Four, Ti (On-C_FourH₉)_Four, T
i (O-iso-C_FourH₉)_Four, Ti (O-2-ethylhexyl)_FourTe
Examples include traalkoxy titanium.

The electron donor used in the preparation of the solid titanium catalyst component (a) includes alcohols, phenols, ketones, aldehydes, carboxylic acids, organic acid halides, esters of organic or inorganic acids, and ethers. Acid amide, acid anhydride, ammonia, amine, nitrile, isocyanate, nitrogen-containing cyclic compound, oxygen-containing cyclic compound, and the like. Of these, carboxylic acids, carboxylic anhydrides, carboxylic esters, carboxylic halides, alcohols, and ethers are preferably used.

Examples of alcohols include methanol, ethanol, propanol, butanol, pentanol, hexanol, 2-ethylhexanol, octanol, dodecanol, octadecyl alcohol, oleyl alcohol, benzyl alcohol, phenylethyl alcohol, cumyl Examples thereof include alcohols having 1 to 18 carbon atoms such as alcohol, isopropyl alcohol and isopropylbenzyl alcohol; and halogen-containing alcohols having 1 to 18 carbon atoms such as trichloromethanol, trichloroethanol and trichlorohexanol.

Examples of the phenols include phenols, cresols, xylenols, ethylphenols, propylphenols, nonylphenols, cumylphenols, naphthols and the like having 6 to 20 carbon atoms which may have a lower alkyl group. Phenols and the like can be mentioned. As ketones, specifically, acetone,
Examples thereof include ketones having 3 to 15 carbon atoms such as methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, and benzoquinone.

Specific examples of aldehydes include aldehydes having 2 to 15 carbon atoms such as acetaldehyde, propionaldehyde, octylaldehyde, benzaldehyde, tolualdehyde, naphthaldehyde and the like. Specific examples of the carboxylic acids include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, pivalic acid, acrylic acid, methacrylic acid, and crotonic acid; malonic acid,
Aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid and fumaric acid; aliphatic oxycarboxylic acids such as tartaric acid; cyclohexanemonocarboxylic acid, cyclohexenemonocarboxylic acid, cis-1,2-cyclohexane Dicarboxylic acid, cis-4-methylcyclohexene-
Alicyclic carboxylic acids such as 1,2-dicarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, anisic acid, p-tert-butylbenzoic acid, naphthoic acid, and cinnamic acid; phthalic acid;
Aromatic polycarboxylic acids such as isophthalic acid, terephthalic acid, naphthalic acid, trimellitic acid, hemimellitic acid, trimesic acid, pyromellitic acid, and melitic acid are exemplified.

As the carboxylic acid anhydrides, specifically, the acid anhydrides of the above carboxylic acids can be used. Specific examples of the organic acid halides include acid halides having 2 to 15 carbon atoms such as acetyl chloride, benzoyl chloride, toluic acid chloride, and anisic acid chloride.

Examples of esters of organic or inorganic acids include methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, and ethyl valerate. , Methyl chloroacetate, ethyl dichloroacetate, methyl methacrylate, ethyl crotonate, ethyl cyclohexanecarboxylate, dimethyl phthalate, diethyl phthalate, di-n-propyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di- n-amyl phthalate, diisoamyl phthalate, ethyl-n-butyl phthalate, ethyl isobutyl phthalate, ethyl-n-propyl phthalate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate , Cyclohexyl benzoate,
Phenyl benzoate, benzyl benzoate, methyl toluate, ethyl toluate, amyl toluate, ethyl ethyl benzoate, methyl anisate, ethyl anisate, ethyl ethoxy benzoate, γ-butyrolactone, δ-valerolactone, coumarin, phthalide And esters of organic or inorganic acids having 2 to 30 carbon atoms such as ethyl carbonate.

Specific examples of ethers include methyl ether, ethyl ether, isopropyl ether, butyl ether, amyl ether, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diamyl ether, diisoamyl ether,
Dineopentyl ether, dihexyl ether, dioctyl ether, methyl butyl ether, methyl isoamyl ether, ethyl isobutyl ether, 2,2-diisobutyl-1,3-dimethoxypropane, 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, 2,2-bis (cyclohexylmethyl) -1,3-dimethoxypropane, 2-isopropyl-2-3,7-dimethyloctyl-1,3-dimethoxypropane, 2,2-diisopropyl-1,3-dimethoxypropane, 2-
Isopropyl-2-cyclohexylmethyl-1,3-dimethoxypropane, 2,2-dicyclohexyl-1,3-dimethoxypropane, 2-isopropyl-2-isobutyl-1,3-dimethoxypropane, 2,2-diisopropyl-1, 3-dimethoxypropane, 2,2-dipropyl-1,3-dimethoxypropane, 2-isopropyl-2-cyclohexyl-1,3-dimethoxypropane,
Examples thereof include 2-isopropyl-2-cyclopentyl-1,3-dimethoxypropane, 2,2-dicyclopentyl-1,3-dimethoxypropane, and 2-heptyl-2-pentyl-1,3-dimethoxypropane.

A specific method for producing the solid titanium catalyst component (a) will be briefly described below with reference to several examples. (1) A method in which a solution comprising a magnesium compound, an electron donor, and a hydrocarbon solvent is contact-reacted with an organometallic compound to precipitate a solid, or a contact reaction is performed with a titanium compound while the solid is precipitated. (2) From a mixture of a magnesium compound, an electron donor, and optionally a solution containing a hydrocarbon solvent and an inorganic or organic carrier, prepare an inorganic or organic carrier on which a magnesium compound is supported, and then contact the titanium compound Method. (3) magnesium compound, titanium compound, electron donor,
A method of obtaining a solid titanium catalyst component (a) carrying magnesium and titanium by contacting a solution containing a hydrocarbon solvent with an inorganic or organic carrier in some cases. (4) A method of contacting a liquid state organomagnesium compound with a halogen-containing titanium compound. At this time, the electron donor is used once. (5) A method in which a liquid state organomagnesium compound is brought into contact with a halogen-containing compound and then brought into contact with a titanium compound. At this time, the electron donor is used once. (6) A method of reacting a liquid magnesium compound having no reducing ability with a liquid titanium compound, preferably in the presence of an electron donor, to precipitate a solid magnesium-titanium composite.

The electron donor is used in an amount of 0.01 to 5 mol, preferably 0.1 to 1 mol, and the titanium compound is used in an amount of 0.01 to 1000 mol, per 1 mol of the magnesium compound.
Preferably, it is used in an amount of 0.1 to 200 mol. In the solid titanium catalyst component (a), the halogen / titanium (atomic ratio) is about 2 to 200, preferably about 4 to 100, and the electron donor / titanium (molar ratio) is about 0.01.
-100, preferably about 0.2-10, and the magnesium / titanium (atomic ratio) is about 1-100, preferably about 2-50.

Such a solid titanium catalyst component (a)
Can be used alone, but can also be used by impregnating a porous substance such as an inorganic oxide or an organic polymer. Specific examples of such a porous inorganic oxide include SiO ₂ , Al ₂ O ₃ , MgO, TiO ₂ , ZrO
_2, SiO ₂ -Al ₂ O ₃ composite oxide, MgO-Al ₂ O ₃
A composite oxide, a MgO—SiO ₂ —Al ₂ O ₃ composite oxide, and the like can be given.

Specific examples of the porous organic polymer include polystyrene, styrene-divinylbenzene copolymer, styrene-n, n'-alkylenedimethacrylamide copolymer, and styrene-ethylene glycol dimethacrylate copolymer. Coalescence, polyethyl acrylate, methyl acrylate-divinylbenzene copolymer, ethyl acrylate
Divinylbenzene copolymer, polymethyl methacrylate,
Methyl methacrylate-divinylbenzene copolymer, polyethylene glycol dimethacrylate, polyacrylonitrile, acrylonitrile-divinylbenzene copolymer, polyvinyl chloride, polyvinylpyrrolidine, polyvinylpyridine, ethylvinylbenzene-divinylbenzene copolymer, polyethylene, Examples include polystyrene-based, polyacrylate-based, polyacrylonitrile-based, polyvinyl chloride-based, and polyolefin-based polymers represented by ethylene-methyl acrylate copolymer and polypropylene.

Of these porous substances, SiO ₂ , A
l ₂ O ₃ and a styrene-divinylbenzene copolymer are preferably used. The organoaluminum compound catalyst component (b) used together with the solid titanium catalyst component (a) in the present invention is a compound having at least one Al-carbon bond in the molecule. Typical examples are shown below by a general formula.

R ⁸ _m AlY _3-m R ⁹ R ¹⁰ Al—O—AlR ¹¹ R ¹² (wherein, R ^{8 to} R ¹² are a hydrocarbon group having 1 to 8 carbon atoms, and Y is halogen or hydrogen. Or an alkoxy group.
R ^{8 to} R ¹² may be the same or different. M is a number represented by 2 ≦ m ≦ 3. Specific examples of the organoaluminum compound include trialkylaluminums such as triethylaluminum, triisobutylaluminum and trihexylaluminum; dialkylaluminum hydrides such as diethylaluminum hydride and diisobutylaluminum hydride; and mixtures of triethylaluminum and diethylaluminum chloride. Mixtures of trialkylaluminums and dialkylaluminum halides; and alkylalumoxanes such as tetraethyldialumoxane and tetrabutyldialumoxane.

Of these organoaluminum compounds,
Trialkylaluminum, a mixture of a trialkylaluminum and a dialkylaluminum halide, and an alkylalumoxane are preferable, and particularly, triethylaluminum, triisobutylaluminum, a mixture of a triethylaluminum and diethylaluminum chloride, or tetraethyldialumoxane is preferable.

Specific examples of the external electron donor catalyst component (c) used together with the solid titanium catalyst component (a) and the organoaluminum compound catalyst component (b) in the present invention include a compound containing a nitrogen atom, , 2,6,6-tetramethylpiperidine, 2,6-dimethylpiperidine, 2,6-diethylpiperidine, 2,6-diisopropylpiperidine, 2,6-diisobutyl-4-methylpiperidine, 1,2,2,6 2,6-pentamethylpiperidine, 2,2,5,5-tetramethylpyrrolidine, 2,5-dimethylpyrrolidine, 2,5-diethylpyrrolidine, 2,5-diisopropylpyrrolidine, 1,2,2,5,5- Pentamethylpyrrolidine, 2,2,5-trimethylpyrrolidine, 2-methylpyridine,
3-methylpyridine, 4-methylpyridine, 2,6-diisopropylpyridine, 2,6-diisobutylpyridine, 1,2,4-trimethylpiperidine, 2,5-dimethylpiperidine, methyl nicotinate, ethyl nicotinate, nicotinic acid Amide, benzoic acid amide, 2-methylpyrrole, 2,5-dimethylpyrrole, imidazole, toluic acid amide, benzonitrile, acetonitrile, aniline, paratoluidine, orthotoluidine, metatoluidine, triethylamine, diethylamine, dibutylamine, tetramethylenediamine And tributylamine.

Compounds containing a sulfur atom include thiophenol, thiophene, ethyl 2-thiophenecarboxylate, ethyl 3-thiophenecarboxylate, 2-methylthiophene, methylmercaptan, ethylmercaptan, isopropylmercaptan, butylmercaptan, and diethylthioether. , Diphenylthioether, methylbenzenesulfonate, methylsulfite, ethylsulfite and the like.

Further, compounds containing an oxygen atom include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2-ethyltetrahydrofuran, 2,2,5,5-tetraethyltetrahydrofuran, 2,2,5,
5-tetramethyltetrahydrofuran, 2,2,6,6-tetraethyltetrahydropyran, 2,2,6,6-tetramethyltetrahydropyran, dioxane, dimethyl ether, diethyl ether, dibutyl ether diisoamyl ether,
Diphenyl ether, anisole, acetophenone, acetone, methyl ethyl ketone, acetylacetone, o-
Examples thereof include tolyl-t-butyl ketone, methyl-2,6-di-t-butylphenyl ketone, ethyl 2-furate, isoamyl 2-furate, methyl 2-furate, and propyl 2-furate.

Further, examples of the organosilicon compound include, for example, compounds represented by the following formula. 'In _4-n (wherein, R and R R _n Si (OR)' is a hydrocarbon group, 0 <n <
4. Specific examples of the organosilicon compound represented by the above general formula include trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, and diphenyldimethoxysilane. Ethoxysilane, bis-o-tolyldimethoxysilane, bis-m-tolyldimethoxysilane, bis-p-tolyldimethoxysilane, bis-p-tolyldiethoxysilane, bisethylphenyldimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane Methoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, decyltrimethoxysilane,
Decyltriethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, n-butyltriethoxysilane, phenyltriethoxysilane, γ-aminopropyltri Ethoxysilane, chlorotriethoxysilane, ethyltriisopropoxysilane, vinyltributoxysilane, ethyl silicate, butyl silicate, trimethylphenoxysilane, methyltriaryloxysilane, vinyltris (β-
Methoxyethoxysilane), vinyltriacetoxysilane, dimethyltetraethoxydisiloxane, and the like.

Organoaluminum compound catalyst component (b)
Is a molar ratio [(b) / Ti atom] per mole of Ti atom in the solid titanium catalyst component (a) in the range of 5 to 1000, and the external electron donor catalyst component (c) is an organoaluminum compound catalyst. The molar ratio per mole of component (b) [(c)
/ (B)] in the range of 0.002 to 0.5.

The particles of the polypropylene resin composition according to the present invention are preferably obtained by supplying each of the above-mentioned catalyst components and ethylene into a first polymerization vessel, preferably by prepolymerization without adding hydrogen, and then forming Without deactivating the catalyst, the polyethylene is preferably transferred from the first polymerization reactor to another polymerization reactor, and propylene and hydrogen or other α-olefin are fed into the polymerization reactor as needed, It can be prepared by performing main polymerization.

The polymerization temperature is usually -50 to 100 ° C., preferably 0 to 90 ° C. when performing slurry polymerization, and is usually 0 to 250 ° C. when performing solution polymerization. And preferably 20 to 200 ° C. When carrying out the gas phase polymerization method, it is desirable that the polymerization temperature is usually 0 to 120 ° C, preferably 20 to 100 ° C.

The polymerization pressure is usually from normal pressure to 100 kg / c.
m ² , preferably normal pressure to 50 kg / cm ² , and the polymerization reaction can be carried out by any of batch, semi-continuous and continuous methods. Further, the polymerization can be performed in two or more stages under different reaction conditions. The polypropylene resin composition particles according to the present invention prepared by the above-described method have a high molecular weight polyethylene (A) having an intrinsic viscosity [η] in the range of 20 to 100 dl / g measured at 135 ° C. in tetralin. 5 to 30 parts by weight and 135
The intrinsic viscosity [η] measured in tetralin at 4.0 ° C is 4.0 to 1
Polypropylene (B) in the range of 2 dl / g
99.5 parts by weight. However, the total amount of both components is 100 parts by weight.

The average particle diameter of the polypropylene resin composition particles according to the present invention prepared by the above method is 50 to 5
It is in the range of 00 μm, preferably 100-300 μm. In addition, a standard sieve of JIS Z8801
The 0 mesh passing amount is 1% or less, preferably 0.5% or less, and the 20 mesh residual amount is 5% or less, preferably 3% or less. Even in the same melt flow rate, the polypropylene resin composition particles within such a particle size range have a remarkably superior melt tension improving effect as compared with the polypropylene resin composition particles outside the above particle size range.

In the present invention, in order to measure the particle size of the polypropylene resin composition particles, a sieve on which 100 g of a sample is placed is passed through a Ro-Tap shaker (trade name: IIDA Seisakusho Co., Ltd.) using a standard sieve specified in JIS Z8801. )
) And driven for 30 minutes for sieving. The average particle diameter in the present invention is a value (μm) obtained by converting the amount of powder passing through a sieve into the particle diameter passing through 50% by weight.
Is the average particle size.

The polypropylene resin composition particles according to the present invention preferably use an olefin polymerization catalyst comprising a solid titanium catalyst component (a) prepared by contacting a liquid magnesium compound and a titanium compound. By producing it, spherical particles having a narrow particle size distribution and a uniform particle size can be obtained. The polypropylene resin composition particles (A) prepared using such an olefin polymerization catalyst have a narrow particle size distribution and contain almost no coarse particles.

The polypropylene resin composition particles according to the present invention may contain another resin or rubber as long as the object of the present invention is not impaired. In the production of the polypropylene resin composition particles according to the present invention, propylene or propylene and an α-olefin having 2 to 20 carbon atoms other than propylene are homopolymerized or copolymerized, and then the other resin or rubber is continuously produced. May be prepared.

Examples of the other resin or rubber include polyethylene; polyα-olefins such as polybutene-1, polyisobutene, polypentene-1 and polymethylpentene-1; ethylene / propylene having a propylene content of less than 75% by weight. Copolymer, ethylene / 1-butene copolymer,
A copolymer of ethylene or an α-olefin with another α-olefin, such as a propylene / 1-butene copolymer having a propylene content of less than 75% by weight;
Less than 5% by weight of ethylene / propylene / 5-ethylidene-2-
Copolymer of ethylene or α-olefin such as norbornene copolymer with other α-olefin and diene monomer; ethylene / vinyl chloride copolymer, ethylene / vinylidene chloride copolymer, ethylene / acrylonitrile copolymer Copolymer, ethylene / methacrylonitrile copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylamide copolymer, ethylene / methacrylamide copolymer, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, Ethylene / maleic acid copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / maleic anhydride copolymer, ethylene / acrylic acid metal salt Copolymer, ethylene / methacrylic acid metal salt copolymer, ethylene / styrene Copolymers of ethylene or α-olefins with vinyl monomers such as polymers, ethylene-methylstyrene copolymers, ethylene-divinylbenzene copolymers; polydiene-based copolymers such as polyisobutene, polybutadiene, and polyisoprene; A random copolymer of a vinyl monomer such as a styrene-butadiene random copolymer and a diene monomer; and a vinyl monomer and a diene monomer such as a block copolymer of styrene, butadiene and styrene. Block copolymer with vinyl monomer; styrene
Vinyl monomers such as hydrogenated butadiene random copolymers and hydrogenated diene monomer random copolymers; vinyl monomers such as hydrogenated styrene / butadiene / styrene block copolymers; Hydrogenated diene monomer / vinyl monomer block copolymer; vinyl monomer / diene monomer such as acrylonitrile / butadiene / styrene copolymer, methyl methacrylate / butadiene / styrene copolymer・ Vinyl monomer graft copolymer; Vinyl polymers such as polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl acetate, polyethyl acrylate, polybutyl acrylate, polymethyl methacrylate;
Examples thereof include vinyl copolymers such as acrylonitrile copolymer, vinyl chloride / vinyl acetate copolymer, acrylonitrile / styrene copolymer, and methyl methacrylate / styrene copolymer.

The amount of addition or polymerization of the other resin or rubber to the polypropylene resin composition particles of the present invention varies depending on the type of the other resin or the type of rubber. It is sufficient that the effect is not impaired, but usually it is preferably about 25% by weight or less. Further, the polypropylene resin composition particles according to the present invention, optionally, conventionally known antioxidants, ultraviolet absorbers, metal soaps, stabilizers such as hydrochloric acid absorbers,
Additives such as a nucleating agent, a lubricant, a plasticizer, a filler, a reinforcing agent, a pigment, a dye, a flame retardant, and an antistatic agent may be contained within a range that does not impair the object of the present invention.

Next, the modified polypropylene resin composition according to the present invention will be described. Modified polypropylene resin composition The modified polypropylene resin composition according to the present invention is prepared by melt-kneading the polypropylene resin composition particles, which are main raw materials, and a radical initiator (C) such as an organic peroxide. In the preparation thereof, a vinyl monomer may be used in combination.

Examples of such a vinyl monomer include vinyl chloride, vinylidene chloride, styrene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, Metal acrylate,
Metal methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylate such as glycyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacryl And methacrylic esters such as 2-ethylhexyl acid, stearyl methacrylate, and glycyl methacrylate.

[Radical initiator (C)] In the present invention, an organic peroxide is used as the radical initiator (C). The organic peroxide used in the present invention is an organic peroxide capable of melting a polypropylene resin composition particle to generate a radical starting point in a polypropylene resin in a molten state, for example, the following general formula: The compound shown by these can be mentioned.

R¹-OO-R^Two Where R¹And R^TwoIs CH_Three, 2-i-C_ThreeH₇OC
₆H_Four, C_TwoH_FiveCH (CH_Three), 4-CH_Three-C₆H_Four, Cl_ThreeC
C (CH_Three)_Two, C₇H₁₅, C-C₆H₁₁CH_Two, 3-t-C_FourH
₉-C₆H_Five, Cl_ThreeSi (CH_Two)_Three, C₆H_Five, CH_ThreeCH
(OCH_Three) CH_TwoCH_Two, C₆H_FiveOCH_TwoH_Two, C₆H_FiveC
H_Two, Z-C₈H₁₇CH = CH (CH_Two)₈, 2-CH_Three-C
₆H_Four, (CH_Three)_TwoCHCH_TwoCH (CH_Three), 3,4-di-CH
_Three-C₆H_Three, Cl_ThreeC, CH_TwoCH (Cl), ClCH_Two,
[C_TwoH_FiveOC (O)]_TwoCH (CH_Three), 3,5-di-CH_Three-
C₆H_Three, C₈H₁₇, C_TwoH_Five, C₁₈H₃₇, 2-oxo-1,3-di
Oxane-4-CH_Two, C_TwoH_FiveCH (Cl) CH_Two, 4-CH_Three
OC₆H_Four, I-C_FourH₉, CH_ThreeSO_TwoCH_TwoCH_Two, C₁₂
H_{twenty five}, C₆H_FiveCH (Cl) CH_Two, H_TwoC = CHCH_Two, 2
-Clc-C₆H_Ten, H_TwoC = C (CH_Three) CH_Two, C-C
H₆H₁₁, ClCH_TwoCH_Two, 4- [C₆H_Five-N = N] -C₆
H_FourCH_Two, Stearyl, 1-naphthyl, 4-t-C_FourH₉-C ₆
H_Ten, 2,4,5-tri-Cl-C₆H_Two, Cl (CH_Two)_Two, C
₁₄H₂₉, 9-florenyl, 4-NO_Two-C₆H_FourCH_Two, 2-i-
C_ThreeH₇-C₆H_Four, CH_ThreeOCH_TwoCH_Two, H_TwoC = C (CH
_Three), 3-CH_Three-C₆H_Four, BrCH_TwoCH_Two, 3-CH_Three-5-i
-C_ThreeH₇-C₆H _Three, Br_ThreeCCH_Two, C_TwoH_FiveOCH_TwoC
H_Two, HC_Two= CH, i-C_ThreeH₇, 2-C_TwoH_FiveCH (CH_Three)
-C₆H_Four, Cl_ThreeCCH_Two, C_FiveH₁₁, C-C₁₂H_{twenty three}, 4-t
-C_FourH₉-C₆H_Four, C₆H₁₃, C_ThreeH₇, CH_ThreeOCH_TwoCH
_Two, C₆H₁₃CH (CH_Three), CH_ThreeOC (CH_Three)_TwoCH_Two
CH_Two, C_ThreeH₇OCH_TwoCH_Two, CH_ThreeOCH_TwoCH (C
H_Three), 2-i-C_ThreeH₇-5-CH_Three-C-C₆H₉, C_FourH₉OC
H_TwoCH_Two, T-C_FourH₉, (CH_Three)_ThreeCCH_TwoSuch as monovalent
Group. Where i is iso and t is tertiary
, Z means cis, and c means cyclic.

Among these compounds, preferred compounds include 2,5-dimethyl-2,5-di # (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di # (t-butylperoxy). )
Hexin-3 and the like. Of these, 2,5-dimethyl-2,5-di # (t-butylperoxy) hexane is particularly preferred because of its excellent crosslinking effect. The organic peroxide comprises polypropylene resin composition particles 1
0.01-5 parts by weight, preferably 0.01-1 part by weight, and more preferably 0.04-0.
5 parts by weight, particularly preferably 0.05 to 0.2 parts by weight.

If the amount of the organic peroxide is less than 0.01 parts by weight, the modifying effect tends to be insufficient, while if it exceeds 5 parts by weight, a gel component may be formed or Not only does the viscosity of the polypropylene resin composition decrease greatly, impairing foaming properties and secondary processing properties, but also the degradation of organic peroxide impairs the food hygiene of the modified polypropylene resin composition, and causes problems such as discoloration and odor. Or

In the method for preparing the modified polypropylene resin composition according to the present invention, for example, first, the polypropylene resin composition particles, the radical initiator (C) and, if necessary, other additives are added to a ribbon blender or a tumbler blender. And a Henschel blender. Next, the mixture obtained as described above is melt-kneaded, whereby a modified polypropylene resin composition having excellent foaming properties can be obtained.

The apparatus used for melt kneading includes, for example, a kneader such as a co-kneader, a Banbury mixer, a Brabender, a single-screw extruder, a twin-screw extruder, a double-screw surface renewing machine, a double-screw multi-disc device, Or a vertical stirrer such as a double helical ribbon stirrer. Among these devices, a twin-screw extruder is particularly preferable because it can perform sufficient kneading and is excellent in productivity. Also,
The melt-kneading may be repeated a plurality of times in order to sufficiently uniformly mix the respective materials.

The heating temperature during the melt-kneading is 150 to
The temperature is 300 ° C, preferably 170 to 250 ° C, more preferably 180 to 220 ° C. Melting and kneading in this temperature range are preferable because the polypropylene resin composition pellets are sufficiently melted and the radical initiator (C) is completely decomposed to obtain a composition that does not change its properties during molding. The time for melt kneading is generally 10 seconds to 5 minutes, preferably 30 seconds to 60 seconds.

The modified polypropylene resin composition obtained as described above has a melt flow rate (MFR; ASTM).
D 1238, 230 ° C, load 2.16 kg) is usually 0.1 to 20 g /
The melt tension is 10 minutes, preferably 0.5 to 5 g / 10 minutes, and the melt tension (MT; the measuring method will be described later in Examples) is usually 1 to 30 g, preferably 5 to 30 g. MFR and MT of modified polypropylene resin composition
Within the above range, the drawdown property during foam molding is improved, and a foam having excellent secondary workability, for example, a foamed sheet can be produced.

Next, a foam according to the present invention and a method for producing the same will be described. Foam and Method for Producing the Foam The foam according to the present invention comprises the above-mentioned modified polypropylene resin composition according to the present invention. The modified polypropylene resin composition may be subjected to foam molding in a state of being simply mixed without being melt-kneaded, or a composition obtained by further melt-kneading as necessary.

The apparatus used for the melt kneading includes, for example, a kneader such as a co-kneader, a Banbury mixer, a Brabender, a single-screw extruder, a twin-screw extruder, a twin-screw surface renewing machine, and a twin-screw multi-disc machine. And a vertical stirrer such as a double helical ribbon stirrer. The following two methods can be mainly exemplified as a method for producing a foam according to the present invention. (1) A method in which the composition containing the modified polypropylene resin composition, the decomposable foaming agent, and if necessary, other additives obtained by the above method is melt-heated to foam-mold. (2) A method in which a volatile foaming agent is press-fitted into a molten modified polypropylene resin composition and then extruded by an extruder to obtain a foam.

In the method (1) for producing a foam, a decomposition-type foaming agent is used as the foaming agent. The decomposition-type blowing agent is a compound that generates a gas such as carbon dioxide gas and nitrogen gas when the blowing agent is decomposed, and may be an inorganic or organic blowing agent. An organic acid or the like that promotes generation may be used in combination. Specific examples of the inorganic decomposition type foaming agent include sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrite, citric acid, sodium citrate and the like.

Examples of the organic decomposition type blowing agent include N-nitroso compounds such as N, N'-dinitrosoterephthalamide and N, N'-nitrosopentamethylenetetramine;azodicarbonamide; Azo compounds such as azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate;
Sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, p, p'-oxybis (benzenesulfenyl hydrazide), diphenylsulfone-3,3'-disulfonyl hydrazide;
Azide compounds such as calcium azide, 4,4'-diphenyldisulfonyl azide, p-toluenesulfonyl azide and the like can be mentioned.

Of these decomposable foaming agents, carbonates or bicarbonates such as sodium bicarbonate are preferred. The addition amount (kneading amount) of the decomposable foaming agent may be appropriately selected depending on the type of the foaming agent and the target expansion ratio, but is usually preferably 0 to 100 parts by weight of the modified polypropylene resin composition. 0.01 to 5 parts by weight, more preferably 0.1 to 1 part by weight.

In order to control the cell diameter of the foam to an appropriate size, an organic carboxylic acid such as citric acid or a foam nucleating agent such as talc may be used in combination, if necessary. The foam nucleating agent used as needed is usually
For 100 parts by weight of the modified polypropylene resin composition,
It is used in a ratio of 0.01 to 2 parts by weight. In the method for producing a foam of the above (1), the modified polypropylene resin composition and the decomposable foaming agent are both supplied to a melt extruder, and the foaming agent is thermally decomposed while being melted and kneaded at an appropriate temperature to form a gas. Is generated, and the molten modified polypropylene resin composition containing this gas is discharged from a die, whereby a foam can be formed.

The melt-kneading temperature and the melt-kneading time in this method may be appropriately selected depending on the foaming agent to be used and the kneading conditions.
At 0 ° C., the melt-kneading time is 1 to 60 minutes. The above (2)
In the method for producing a foam, a volatile foaming agent can be used as the foaming agent.

Preferred volatile foaming agents include, for example, aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclobutane, cyclopentane and cyclohexane; chlorodifluoromethane, difluoro Methane, trifluoromethane, trichlorofluoromethane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, trichlorofluoromethane, chloromethane, chloroethane,
Dichlorotrifluoroethane, dichlorofluoroethane, chlorodifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane,
Halogenated hydrocarbons such as tetrachlorodifluoroethane, chloropentafluoroethane and perfluorocyclobutane; inorganic gases such as carbon dioxide, nitrogen and air; and water.

The addition amount (kneading amount) of such a volatile foaming agent varies depending on the type of the foaming agent and the target expansion ratio.
It is preferably in the range of 0.01 to 5 parts by weight, more preferably 0.1 to 2 parts by weight with respect to parts by weight. Further, in the method for producing a foam of the above (2), the modified polypropylene resin composition is melted in an extruder, a volatile foaming agent is press-fitted in the extruder, and the modified polypropylene resin in a molten state is maintained at a high pressure. The kneaded product of the modified polypropylene resin composition and the volatile foaming agent, which are kneaded with the resin composition and sufficiently kneaded, is extruded from a die.

The melt-kneading temperature and the melt-kneading time in this method may be appropriately selected depending on the foaming agent to be used and the kneading conditions, and vary depending on the type of the resin. The time is between 1 and 120 minutes. Also in the foam production methods (1) and (2), the melt is melted by an extruder, and a melt having foam cells is discharged from a T die or a cylindrical die, preferably by forming a sheet. It can be formed into a foam. When discharging from a cylindrical die, the cylindrical sheet is usually cut into one or a plurality of pieces, and then the smoothed sheet is taken out.

The foam according to the present invention obtained by the above-described method has a high density (ASTM D) because of its light weight, heat insulation, buffering of external stress or compressive strength. 1505) is preferably from 0.09 to 0.6 g / cm ³ , more preferably from 0.15 to 0.3 g / cm ³
Is more preferable. Therefore, the expansion ratio of the modified polypropylene resin composition is preferably from 1.3 to
The range is 10 times, particularly 1.6 to 6 times.

Further, the foam according to the present invention has a closed cell ratio of 50% or more in that it has suitable heat resistance, good cushioning of external force, and suitable compression strength characteristics. And more preferably 70% or more. In the method for producing a foam according to the present invention, the shapes that can be produced include sheet-like, board-like, plate-like, hollow, tube-like, bag-like, etc .; columnar, elliptical, prismatic, and strands. Various shapes such as column shape such as shape;

[0080]

The polypropylene resin composition particles according to the present invention are formed from polypropylene (B) containing a small amount of a specific high molecular weight polyethylene (A), so that the viscosity increases during elongation deformation and the melt tension is increased. Is high. Further, since the polypropylene resin composition particles according to the present invention have a uniform particle size and a narrow particle size distribution, they hardly contain fine powder or coarse particles. as a result,
Compared with polymer particles having a similar composition having a wide particle size distribution, they are more excellent in terms of the degree of increase in viscosity during elongation deformation and the magnitude of melt tension. Also, in the manufacturing process of the particles, trouble due to fine powder during drying (for example, dust explosion)
Can be prevented.

The modified polypropylene resin composition according to the present invention has a sharp increase in viscosity during elongation deformation, has a high melt tension, and has an appropriate melt flow rate. Suitable for use as a material. The foamed sheet produced from the modified polypropylene resin composition according to the present invention has low drawdown and good secondary moldability, and can be used to mass-produce trays and the like from the foamed sheet by hot-pressure pneumatic molding or vacuum molding. Can be.

The foam according to the present invention is lightweight, has high rigidity, is excellent in chemical resistance and food hygiene, is well-shaped, and has a beautiful appearance. It can be used for packaging fresh foods or processed foods, especially for cup ramen, ice cream containers, fish and meat trays.

[0083]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In addition, the physical property in an Example and a comparative example was measured by the following method. (1) Melt flow rate (MFR) The melt flow rate was measured at 230 ° C. under a load of 2.16 kg by a method specified in ASTM D1238. (2) Melt tension (MT) Melt tension measuring device [Toyo Seiki Seisakusho Co., Ltd.]
Using an orifice (L = 8.00 mm, D = 2.0
95mm), set temperature 230 ° C, piston descending speed 30
The winding load of the pulley with load cell detection was measured under the conditions of mm / min and a winding speed of 4 mm / min, and the measured load was used as the melt tension.

[0084]

Example 1 <Production of polypropylene resin composition particles (1)> [Preparation of solid titanium catalyst component] 7.14 g of anhydrous magnesium chloride, 37 ml of decane and 35.1 ml of 2-ethylhexyl alcohol were heated at 130 ° C for 2 hours. After performing the reaction to obtain a homogeneous solution, phthalic anhydride (1.
67 g was added, and the mixture was further stirred and mixed at 130 ° C. for 1 hour to dissolve phthalic anhydride in the homogeneous solution. Then
After cooling the homogeneous solution thus obtained to room temperature,
The whole amount was dropped into 200 ml of titanium tetrachloride kept at -20 ° C over 1 hour. After the charging, the temperature of the mixture was raised to 110 ° C. over 4 hours. When the temperature reached 110 ° C., 4.0 ml of isobutyl phthalate was added, and the mixture was stirred and maintained at the same temperature for 2 hours. After the completion of the reaction for 2 hours, a solid portion was collected by hot filtration, and the solid portion was collected for 275 m.
1 Titanium tetrachloride and then again at 110 ° C. for 2 hours.
The heating reaction was performed for hours. After the completion of the reaction, a solid portion was collected again by hot filtration, and the solution was heated at 110 ° C. in decane and hexane.
Washing was sufficiently performed until no free titanium compound was detected in the washing solution to obtain a solid titanium catalyst component composed of spherical particles. [Production of polypropylene resin composition particles (1)] In a polymerization tank having a content of 3000 liters, heptane 1180 liters and triethyl aluminum 148 were placed under a nitrogen atmosphere.
g, dicyclopentyldimethoxysilane (DCPM
S) 299 g and 78 g of the solid titanium corrosion medium component were charged. Under ethylene of 0.3 kg / cm ² (gauge) in the polymerization tank, the temperature was raised after ethylene was charged. Upper limit temperature 45 ° C
With the internal pressure of the polymerization tank being 3 kg / cm ² (gauge) at the upper limit, the planned amount of ethylene was continuously charged, and the reaction pressure was 3
The polymerization was continued for hours. Residual pressure in polymerization tank 1kg / cm
^When a part of the slurry in the polymerization tank was sampled and analyzed near ² (gauge), 1
The intrinsic viscosity [η] measured in tetralin at 35 ° C. is 35.
It was 0 dl / g.

Subsequently, the nitrogen in the polymerization tank was removed by a vacuum pump, and the temperature was raised while propylene was charged. The polymerization temperature was increased to 70 ° C., and the internal pressure was increased to 6 kg / cm ² (gauge). Under the above, propylene was continuously charged, and a predetermined amount of propylene was polymerized. After the completion of the polymerization, 144.3 ml of methanol was charged to stop the polymerization, and the resultant was purified and dried by a usual method to obtain 520 kg of a polymer.

The intrinsic viscosity [η] of the polypropylene part of the obtained polypropylene resin composition particles (1) measured in tetralin at 135 ° C. was 7.2 dl / g. From the infrared absorption measurement of the particles (1), The content of the structural unit derived from ethylene (hereinafter, referred to as ethylene content) is 7.0.
% By weight. As a result of measuring the particle size of the polypropylene resin composition particles (1) produced by the above method, the average particle size was 200 μm, and the 200 mesh passage was 0.1 μm.
It was 2%, and the 20 mesh residue was 0%. <Production of modified polypropylene resin composition (1)> 100 parts by weight of the polypropylene resin composition particles (1) obtained above and 2,5-dimethyl-2,5- as a radical polymerization initiator
0.08 parts by weight of di # (t-butylperoxy) hexane is co-directionally fully intermeshing type twin screw extruder [manufactured by Technovel Co., Ltd.
KZW25-30MG, screw diameter 31mmφ, L /
D = 30], melt-kneaded at a resin temperature of 210 ° C. and a screw rotation speed of 200 rpm (average residence time: 30 seconds), and melt-extruded to obtain pellets of the modified polypropylene resin composition (1).

This modified polypropylene resin composition (1)
, And MFR and melt tension were measured according to the above-mentioned method. Table 1 shows the results.

[0088]

Example 2 The procedure of Example 1 was repeated except that the polypropylene resin composition particles (1) having an ethylene content of 1.0% by weight determined by infrared absorption measurement were used instead of the polypropylene resin composition particles (1). Similarly, pellets of the modified polypropylene resin composition (2) were obtained.

The polyethylene obtained first at the time of producing the polypropylene resin composition particles (2) is as follows:
The intrinsic viscosity [η] measured in tetralin at 135 ° C. is 3
It was 5.0 dl / g. The intrinsic viscosity [η] of the polypropylene portion of the polypropylene resin composition particles (2) measured in tetralin at 135 ° C. was 7.2 dl / g.
Met.

Further, as a result of measuring the particle size of the polypropylene resin composition particles (2), the average particle size was 200 μm, the passing amount through 200 mesh was 0.2%, and the remaining portion through 20 mesh was 0%. . Using the pellets of the above modified polypropylene resin composition (2), MFR and melt tension were measured according to the above method. The results are shown in Table 1.

[0091]

Comparative Example 1 <Production of polypropylene resin composition particles (3)> [Preparation of solid titanium catalyst component] Steel ball 9 having a diameter of 12 mm 9
A vibration mill equipped with four crushing pots having a capacity of 4 liters and containing 4 kg was prepared. 300 g of magnesium chloride and 75 g of diisobutyl phthalate were added to each pot in a nitrogen atmosphere.
ml and 60 ml of titanium tetrachloride were added and pulverized for 40 hours.

Next, 100 g of the co-ground product obtained as described above was placed in a flask having a capacity of 2 liters, 600 ml of toluene was added thereto, and the mixture was stirred at 114 ° C. for 30 minutes. . Next, the remaining solid was washed three times with 1 liter of n-heptane at 20 ° C., and further dispersed in 1 liter of n-heptane to obtain a transition metal catalyst component slurry. And this slurry was vacuum-dried at 100 degreeC, and n-heptane was vaporized, and the solid titanium catalyst was obtained.

The solid titanium catalyst component obtained as described above contained 1.9% by weight of titanium and 14.2% by weight of diisobutyl phthalate. [Production of polypropylene resin composition (3)] Content 30
Under a nitrogen atmosphere, a heptane 11
80 liters, 148 g of triethylaluminum and 78 g of the above solid titanium catalyst component were charged. Under ethylene of 0.3 kg / cm ² (gauge) in the polymerization tank, the temperature was raised after ethylene was charged. When the upper limit temperature is 35 ° C and the internal pressure of the polymerization tank is 3
At the upper limit of kg / cm ² (gauge), the expected amount of ethylene was continuously charged, and the polymerization was continued for 3 hours including the residual pressure reaction. When a part of the slurry in the polymerization tank was sampled and analyzed near the residual pressure of 1 kg / cm ² (gauge) in the polymerization tank, the intrinsic viscosity [η] of the obtained polyethylene measured in tetralin at 135 ° C. was 35. 0.0 dl / g.

Subsequently, triethyl aluminum 148
g and dicyclopentyldimethoxysilane (DCPMS)
299 g was added to the polymerization tank, nitrogen in the polymerization tank was removed by a vacuum pump, and the temperature was increased while propylene was charged.
At a polymerization temperature of 70 ° C. and an internal pressure of 6 kg / cm ² (gauge) as the upper limit, propylene was continuously charged under a hydrogen-free concentration to cause a predetermined amount of propylene to undergo a polymerization reaction.

Then, after the polymerization was completed, methanol was added to 144.
The polymerization was terminated by charging 3 ml, and purified and dried by a usual method to obtain 500 kg of a powder polymer. Intrinsic viscosity [η] of the polypropylene part of the obtained polypropylene resin composition particles (3) measured in tetralin at 135 ° C.
Was 6.7 dl / g, and the ethylene content of the particles (3) determined by infrared absorption measurement was 0.9% by weight.

As a result of measuring the particle size of the polypropylene resin composition particles (3) produced by the above method, the average particle size was 200 μm, the passing through 200 mesh was 20%, and the residual 20 mesh was 0.1%. %Met. It was confirmed that fine particles and coarse particles were present in the particles (3). <Production of modified polypropylene resin composition (3)> Except that 0.08 part by weight of the radical initiator used in Example 1 was added to the above polypropylene resin composition particles (3), in the same manner as in Example 1. Thus, pellets of the modified polypropylene resin composition (3) were obtained.

This modified polypropylene resin composition (3)
, And MFR and melt tension were measured according to the above-mentioned method. The results are shown in Table 1.

[0098]

Comparative Example 2 The same procedure as in Comparative Example 1 was carried out except that the temperature at the time of charging ethylene was 50 ° C. to carry out the polymerization of ethylene.
Polypropylene resin composition particles (4) and pellets of the modified polypropylene resin composition (4) were prepared, and their MFR and melt tension were measured. The results are shown in Table 1.

The intrinsic viscosity [η] of the polyethylene obtained by polymerizing ethylene as described above in tetralin at 135 ° C. was 15 dl / g. The intrinsic viscosity [η] of the polypropylene part of the obtained polypropylene resin composition particles (4) measured in tetralin at 135 ° C. was 6.4 dl / g, which was determined from infrared absorption measurement of the particles (4). Ethylene content is 6.0% by weight
Met.

As a result of measuring the particle size of the polypropylene resin composition particles (4), it was found that the average particle size was 150 μm,
The 0 mesh passing amount was 20%, and the 20 mesh residual amount was 0.2%. From the catalyst particle size calculated backward from this powder, it is impossible to supply the catalyst with a catalyst supply pump in the production process due to partial large particle size particles.

[0101]

Example 3 100 parts by weight of pellets of the modified polypropylene resin composition (1) used in Example 1 and a blowing agent masterbatch [trade name: PE-RM410EN, manufactured by Dainichi Seika Co., Ltd., sodium bicarbonate / 3 parts by weight of citric acid] were mixed with a tumbler blender for 3 minutes.

Next, from this mixture, 80 mm
An annular foamed sheet having a thickness of 0.8 mm was formed using a 65 mm single screw extruder (L / D = 28) provided with a circular die of φ and a mandrel of 190 mmφ. The expansion ratio of the annular foam sheet in this manufacturing apparatus was 2.4. One corner of this annular foam sheet was cut open and taken out as a smooth sheet by a take-off machine.

The foaming ratio, appearance, cell shape and secondary formability (vacuum formability) of the obtained foamed sheet were evaluated according to the following methods. The results are shown in Table 2. (1) Sheet appearance The sheet appearance was visually evaluated according to the following evaluation criteria. <Evaluation Criteria for Sheet Appearance> ：: No unfoamed portion, unevenness, and corrugate are observed.

×: Unfoamed portions, irregularities, corrugates are seen. (2) Foaming Ratio M The apparent density (D) was calculated from the weight of the foamed sheet and the volume obtained by the submersion method, and the foaming ratio M was calculated from the true specific gravity (0.90) by the following formula. M = 0.90 / D (3) Cell shape As for the cell shape, the cross section of the foamed sheet was observed by an SEM photograph, and the state of air bubbles was observed. The case where adjacent air bubbles were independent of each other was evaluated as “independent”, and the case where adjacent air bubbles were connected was evaluated as “communication”. (4) Secondary workability 50 mm in diameter, 30 mm, 40 mm, 50 mm in depth
After the foamed sheet was heated at 160 ° C. for 1 minute using a mold capable of simultaneously vacuum forming the three cups, the hanging down distance (drawdown property) was measured by infrared rays. (The higher the numerical value, the worse the anti-drawdown property.) In addition, the shape of the molded cup was evaluated as good or poor, and the appearance of the cup was evaluated according to the following five grades.

5: very beautiful 4: beautiful but broken corners 3: slightly poor shape 2: poor shape and uneven thickness 1: breaking

[0106]

Example 4, Comparative Example 3 and Comparative Example 4 In Example 3, the modified polypropylene composition (2) was replaced with pellets of the modified polypropylene composition (1).
Example 3 except that the pellets were changed to (3) and (4).
In the same manner as in the above, a foamed sheet having a thickness of 0.8 mm was formed. Each of the obtained foam sheets was evaluated in the same manner as in Example 3. Table 2 shows the results.

[0107]

[Table 1]

[0108]

[Table 2]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Sasaki 1-6 Takasago, Takaishi-shi, Osaka, Japan Within Grand Polymer Co., Ltd. (72) Inventor Tadao Nariki 1-6 Takasago, Takaishi-shi, Osaka In Grand Polymer, Inc. (72) Inventor Naoya Akiyama 580-32 Nagaura, Sodegaura-shi, Chiba Prefecture Within Grand Polymer Co., Ltd. (72) Inventor Yoichi Wakita 580-32 Nagaura, Sodegaura-shi, Chiba Prefecture Within Grand Polymer Co., Ltd. (72) Invention Person Takayuki Yamada 580-32 Nagaura, Sodegaura-shi, Chiba F-term in Grand Polymer Co., Ltd. (reference) 4F070 AA14 AA15 GA05 GA08 GB07 4F074 AA17 AA24 CA22 DA02 4J002 BB032 BB121 EK036 FD146 GG01

Claims (7)

[Claims] 1. 0.5 to 30 parts by weight of a high molecular weight polyethylene (A) having an intrinsic viscosity [η] of 20 to 100 dl / g measured in tetralin at 135 ° C., and an intrinsic viscosity [η] measured in tetralin at 135 ° C. η] is 4.
0 to 12 dl / g polypropylene (B) 70 to 9
9.5 parts by weight [Total amount of component (A) and component (B) is 1
00 parts by weight], of which particles having a mesh passing through a 200-mesh by a standard sieve according to JIS Z8801 are 1% or less and a 20-mesh residual is 5% or less. A polypropylene resin composition particle characterized by the above-mentioned. 2. The polypropylene resin composition particles according to claim 1, wherein the high molecular weight polyethylene (A) is produced by prepolymerization at the time of producing the polypropylene (B). 3. The method according to claim 2, wherein the polypropylene resin composition particles are produced using a solid titanium catalyst component (a) prepared by contacting a liquid magnesium compound and a titanium compound. The polypropylene resin composition particles according to claim 1 or 2, wherein 4. A blend of 100 parts by weight of the polypropylene resin composition particles according to any one of claims 1 to 3 and 0.01 to 5 parts by weight of a radical initiator (C) is mixed with 150 to 30 parts by weight.
A modified polypropylene resin composition obtained by melt-kneading at 0 ° C. 5. The modified polypropylene resin according to claim 4, wherein said radical initiator (C) is 2,5-dimethyl-2,5-di # (t-butylperoxy) hexane. Composition. 6. A foam comprising the modified polypropylene resin composition according to claim 4 or 5. 7. A mixture comprising the modified polypropylene resin composition according to claim 4 and an organic foaming agent (D) and / or an inorganic foaming agent (E) is heated by an extruder, melt-kneaded and then extruded. And producing a foam.