JP2006241356A - Polypropylene resin composition for foam molding with T-die and foam molded body thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polypropylene-based resin composition for expansion molding, which has a low open-cell ratio in an addition system of an inorganic filler and has excellent expansion properties such as sheet appearance, etc., and its expansion molding. <P>SOLUTION: The polypropylene-based resin composition for expansion molding by a T die comprises (A) 5-40 wt% of a polyolefin component having 5-30g melt tension at 230°C, (B) 5-90 wt% of a polypropylene-based resin satisfying (1) 1.5-7.0g melt tension at 190°C, (2) 3-10g/10 minutes melt flow rate, (3) the ratio of a weight-average molecular weight (Mw) to a number-average molecular weight (Mn) of 5-8 and 950,000-2,000,000 Z average molecular weight (Mz) and (4) 2-7 seconds relaxation time (τ) at an angular frequency ω=0.1rad/second in a melt viscoelasticity behavior measured by using a rotary rheometer and (C) 5-25 wt% of an inorganic filler. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polypropylene resin composition for foam molding using a T-die and a foam molded body thereof.

  In recent years, with the spread of microwave ovens and the increase in convenience stores, the demand for containers for microwave ovens has increased. The container is required to have heat insulation, heat resistance, and oil resistance, and a polypropylene resin is one of the preferred materials. However, since it is a crystalline resin, the melt viscosity is extremely high above the melting point with respect to the crystalline melting point. There was a problem that it was lowered and foamed bubbles could not be held and easily broken. To solve this problem, high melt tension polypropylene with a branched chain added to linear polypropylene or a small amount of a high molecular weight component having a very high viscosity is used. A foam having an excellent rate) is obtained. On the other hand, talc is added to obtain container rigidity. However, since the open cell ratio is increased by the addition of talc, a molded product that can be satisfied only with a system that uses high melt tension polypropylene as the main raw material is obtained. There wasn't.

For example, Patent Documents 1 and 2 disclose a system in which talc is added to high melt tension polypropylene.
However, in the example of Patent Document 1, the closed cell ratio is as low as about 55 to 65%, and only a container having a non-uniform thickness and a poor mold reproducibility is obtained due to the progress of bubble breaking during thermoforming. Moreover, in the Example of patent document 2, the system which added talc (talc 10%) has an open cell ratio of about 15% with respect to 30 parts by weight of PF-814, which is a high melt tension polypropylene. . The effect is that the open cell ratio is high for the blending amount of PF-814, and the balance between foaming performance and cost is not obtained.
Therefore, there is a demand for a material that is a system in which a small amount of high melt tension polypropylene is added, has a low open cell ratio (high closed cell ratio), and has excellent foaming characteristics with excellent sheet appearance.
JP 2004-122717 A JP 2001-226510 A

  An object of the present invention is to provide a polypropylene resin composition for foam molding that has a low open cell ratio in an inorganic filler-added system and is excellent in foaming characteristics such as sheet appearance, and a foamed molded product thereof.

According to the present invention, the following polypropylene-based resin composition for foam molding and the foam-molded body thereof are provided.
1. A polypropylene resin composition for foam molding with a T-die comprising the following components (A), (B) and (C).
(A) Polyolefin component having a melt tension of 5 to 30 g at 230 ° C .: 5 to 40% by weight
(B) Polypropylene resin satisfying the following (1) to (4): 5 to 90% by weight
(1) Melt tension at 190 ° C. is 1.5 to 7.0 g
(2) Melt flow rate is 3 to 10 g / 10 min. (3) Ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) is 5 to 8, Z average molecular weight (Mz) is 950,000. ˜2 million (4) In melt viscoelastic behavior measured using a rotational rheometer, the relaxation time (τ) at an angular frequency ω = 0.1 rad / sec is 2 to 7 seconds (C) Inorganic filler: 5 25% by weight
2. Component (A) was obtained by producing a propylene polymer in the polymerization step in the presence of a pre-activated catalyst in which an ultrahigh molecular weight ethylene polymer was supported on a polymerization catalyst, and subsequently producing an olefin polymer. 2. The polypropylene resin composition for foam molding according to 1, which is an olefin multistage polymer.
3. 2. The polypropylene resin composition for foam molding according to 1, wherein the component (A) is a polypropylene resin into which a long chain branch obtained by irradiating ionizing radiation is introduced.
4). 2. The polypropylene resin composition for foam molding according to 1, wherein the component (A) is a propylene polymer composition obtained by contacting a polypropylene resin, an organosilicon compound and a high molecular weight acid-modified α-olefin polymer.
5. A) Component polymerizes or copolymerizes one or more monomers selected from ethylene, propylene, α-olefins having 4 to 20 carbon atoms, styrenes and cyclic olefins by a two-stage polymerization method in the presence of polyene. 2. The polypropylene resin composition for foam molding according to 1, which is a polyolefin resin obtained in the above manner.
6). (B) A catalyst comprising a solid catalyst component obtained by treating a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound with an ether and an electron acceptor and an organoaluminum compound as essential components The polypropylene resin composition for foam molding according to any one of 1 to 5, which is a polypropylene resin obtained by polymerizing propylene in the presence of.
7). (C) The polypropylene resin composition for foam molding according to any one of 1 to 6, wherein the component is talc having an average particle size of 30 μm or less measured by a laser method.
The foaming molding which satisfy | fills following (1) and (2) obtained by foam-molding the polypropylene resin composition for foam molding as described in any one of 8.1-7.
(1) Average cell diameter is 500 μm or less (2) Open cell ratio is 1 to 30%

According to the present invention, there are provided a polypropylene resin composition for foam molding which has a low open cell ratio in an inorganic filler addition system and is excellent in foaming characteristics such as sheet appearance, and a foamed molded article thereof. Therefore, according to the present invention, productivity can be improved and costs can be reduced.

Hereinafter, the components contained in the polypropylene resin composition of the present invention will be described.
(A) Polyolefin component Polyolefin resin having a melt tension of 5 to 30 g measured as a polyolefin component (A) (hereinafter referred to as (A) component) using a capilograph at a measurement temperature of 230 ° C. and a take-off speed of 3.1 m / min. Is used. If it is such a polyolefin-type resin, there will be no restriction | limiting in particular. If it is less than 5 g, the foaming characteristics are lowered (foaming ratio is lowered and the open cell ratio is increased), and the thermoformability may be lowered. If it exceeds 30 g, productivity may be lowered. Preferably, the melt tension is 7-25 g.
Suitable polyolefin resins include polypropylene resins (eg, homopolypropylene, block polypropylene, random polypropylene, random block polypropylene, etc.).

As the polyolefin component having such a predetermined melt tension, the following polyolefin resins can be used.
(1) An olefin multi-stage polymer obtained by producing a propylene polymer in a polymerization step and subsequently producing an olefin polymer in the presence of a pre-activated catalyst in which ultra high molecular weight polyethylene is supported on a polymerization catalyst. The high molecular weight polyethylene preferably has an intrinsic viscosity of 15 to 160 dl / g measured in tetralin at 135 ° C.
As the olefin polymerization catalyst, a catalyst component mainly composed of a transition metal compound catalyst component containing a titanium compound, preferably a titanium-containing solid catalyst component can be used, and an organic metal compound and an electron donor can be combined.
Details of the production method of this polymer are described in International Publication No. WO97 / 20869 (Japanese Patent Application No. 09-521155) and JP-A No. 2002-356601.

(2) Polypropylene resin introduced with long-chain branches obtained by irradiating ionizing radiation Polypropylene resin (for example, homopolypropylene, block polypropylene, random polypropylene, random block polypropylene, etc.) is irradiated with ionizing radiation. The obtained polypropylene resin can be used suitably. Examples of the ionizing radiation include α rays, β rays, γ rays, X rays, electron beams, and the like. Among these, an electron beam is preferable for practical use. The resin obtained by this method (ionizing radiation) has a free-end long-chain branched structure. As specific production conditions in the electron beam crosslinking method, the conditions described in JP-A-62-1121704 and JP-A-2-69533 can be used.
Examples of such commercially available resins include Profax PF-814, Pro-fax SD-632 (manufactured by Montel SDK Sunrise Co., Ltd., trade name), and the like.

(3) Propylene polymer composition obtained by contacting a polypropylene resin, an organosilicon compound and a high molecular weight acid-modified α-olefin polymer. As such a propylene polymer composition, for example, (a) 135 ° C, 100 parts by mass of polypropylene having an intrinsic viscosity [η] measured in tetralin of 0.7 to 5 dl / g,
(B) General formula (1)
_{X n SiY m (OR) 4-} (n + m) (1)
Wherein X is a substituent containing a group capable of reacting with a carboxylic acid or an anhydride thereof, Y is a hydrocarbon group, a hydrogen atom or a halogen atom, R is a hydrocarbon group, n is 1 to 3, m Represents an integer of 0 to 2, and (n + m) = 1 to 3.)
0.001 to 1 part by mass of an organosilicon compound represented by: and (c) 0.001 to 1% by mass of an acid derived from an erodible carboxylic acid and / or an anhydride thereof, and at 135 ° C. in tetralin A propylene polymer composition obtained by bringing 0.1 to 30 parts by mass of a modified α-olefin polymer having 2 to 20 carbon atoms having a measured intrinsic viscosity [η] of 0.7 dl / g or more is mentioned.

Examples of the organosilicon compound represented by the general formula (1) include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 4-aminobutyltriethoxysilane, and p-aminophenyltrimethoxysilane. .
The high molecular weight acid-modified α-olefin polymer preferably has an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 0.7 dl / g or more, and is an unsaturated carboxylic acid and / or anhydride thereof. It has been denatured. Specifically, as a high molecular weight acid-modified α-olefin polymer, modified with maleic anhydride, acrylic acid, methacrylic acid or the like having an intrinsic viscosity [η] measured in tetralin of 135 ° C. of 0.7 dl / g or more. And propylene polymer, 1-butene polymer, and the like.
Regarding other specific manufacturing conditions in this manufacturing method, the conditions described in JP-A-2004-75946 can be used.
By this method, a melt tension developing component having a branched structure is formed in the polymerization composition.

(4) Obtained by polymerizing or copolymerizing one or more monomers selected from ethylene, propylene, α-olefins having 4 to 20 carbon atoms, styrenes and cyclic olefins by a two-stage polymerization method in the presence of polyene. The resulting polyolefin resin (A) is obtained by a two-stage polymerization method in the presence of polyene (for example, 1,7-octadiene, 1,9-decadiene, 1,5-hexadiene, etc.), ethylene, propylene, carbon number 4 ~ 20 α-olefins (eg 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene etc.), styrenes (eg styrene, p-methylstyrene etc.) and cyclic olefins (eg And polyolefin resins obtained by polymerizing or copolymerizing one or more monomers selected from, for example, norbornene) Rukoto can. In this method, a melt tension developing component having a branched structure is formed in the resin.

  Specifically, in the presence of a catalyst in which a catalyst component including a transition metal compound of Group 4 of the periodic table having a cyclopentadienyl skeleton and a promoter component is combined, ethylene, propylene, and a carbon number of 4 to 20 a first polymerization step of polymerizing or copolymerizing one or more monomers selected from α-olefin, styrenes and cyclic olefins, and a homopolymer or a copolymer obtained in the first polymerization step, One or two selected from ethylene, propylene, α-olefins having 4 to 20 carbon atoms, styrenes and cyclic olefins in the presence of a polyene having at least two carbon-carbon double bonds polymerizable in one molecule It can manufacture from the manufacturing method including the 2nd polymerization process of copolymerizing the above monomer. The co-catalyst components used in this method include (i) aluminoxane, (ii) ionic compounds that can be converted to cations by reacting with the transition metal compounds, and (iii) clays, clay minerals, and ion-exchange layered compounds. At least one selected from among them can be used.

  Further, in the presence of a catalyst obtained by combining a titanium trichloride-based compound or a catalyst component containing titanium, magnesium and a halogen element as essential components and an organoaluminum compound, from ethylene, propylene and an α-olefin having 4 to 20 carbon atoms. A first polymerization step in which one or two or more selected monomers are polymerized or copolymerized, and a homopolymer or copolymer obtained in the first polymerization step can be polymerized in one molecule. Producing from a production method comprising a second polymerization step of copolymerizing one or two or more monomers selected from ethylene, propylene and an α-olefin having 4 to 20 carbon atoms in the presence of a polyene having at least two bonds. Can do. Examples of the organoaluminum compound include triethylaluminum, triisobutylaluminum, diethylaluminum monochloride, and the like.

  About the other specific manufacturing conditions in said manufacturing method, the conditions as described in an international publication 02/072649 pamphlet and Japanese Patent Application No. 2004-331795 can be used.

  The proportion of the component (A) in the resin composition of the present invention is 5 to 40% by weight, preferably 7 to 30% by weight. If it is less than 5%, the foaming characteristics are lowered (the open cell ratio is increased and the sheet appearance is deteriorated), and the thermoformability is also lowered. When it exceeds 40% by weight, productivity deteriorates.

(B) Polypropylene resin The polypropylene resin (B) (hereinafter referred to as component (B)) contained in the composition of the present invention satisfies the following (1) to (4).
(1) Melt tension at 190 ° C. is 1.5 to 7.0 g
(2) Melt flow rate (MFR) is 3 to 10 g / 10 minutes (3) Ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) is 5 to 8, Z average molecular weight (Mz) 950,000 to 2,000,000 (4) In the melt viscoelastic behavior measured using a rotary rheometer, the relaxation time (τ) at an angular frequency ω = 0.1 rad / sec is 2 to 7 seconds.

  In the above (1), if the melt tension is less than 1.5 g, the open cell ratio increases, the foam cell diameter increases, the mold reproducibility at the time of thermoforming deteriorates, etc., which is not preferable. On the other hand, if it exceeds 7.0 g, the high molecular weight component is increased, and the stretchability is lowered. The melt tension of the component (B) is preferably 1.5 to 3.5 g.

  In the above (2), if the MFR is less than 3 g / 10 minutes, the surface of the sheet becomes rough during foam molding, which is not preferable. On the other hand, if it exceeds 10 g / 10 minutes, the open cell ratio is undesirably increased. The MFR of the component (B) is preferably 4 g / 10 minutes to 7 g / 10 minutes.

  In the above (3), if the ratio (Mw / Mn) of Mw and Mn obtained from the molecular weight distribution curve measured by gel permeation chromatography is less than 5, the open cell ratio is undesirably high. On the other hand, if it exceeds 8, the surface of the sheet may be roughened due to the large amount of high molecular weight components during foam molding. (B) Mw / Mn of a component becomes like this. Preferably it is 5-7. Moreover, if Z average molecular weight is less than 950,000, tension | tensile_strength will become weak and it will break and it will be easy to become a continuous bubble. On the other hand, if it exceeds 2 million, there is a possibility that the sheet breaks if the appearance is bad due to the entanglement of high molecular weight components. The Mz of the component (B) is preferably 1 million to 2 million.

In the above (4), in the melt viscoelastic behavior obtained by measurement using the rotational rheometer of the component (B), if the relaxation time τ (second) at the angular frequency ω = 0.1 rad / second is less than 2 seconds, the tension Since the foaming cell is weak, the foamed cell tends to break up and become open bubbles. On the other hand, if it exceeds 7 seconds, the surface of the sheet may be roughened due to the large amount of high molecular weight components. The relaxation time τ (second) of the component (B) is preferably 2.0 seconds to 3.5 seconds.
Details of the relaxation time are described in the specification of Japanese Patent Application No. 2004-331795.

  The component (B) is preferably an essential component of a solid catalyst component obtained by treating a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound with an ether and an electron acceptor, and an organoaluminum compound. A polypropylene resin obtained by polymerizing propylene in the presence of a catalyst.

  Examples of the organoaluminum compound that reduces titanium tetrachloride in the solid catalyst component include (a) alkylaluminum dihalide, specifically, methylaluminum dichloride, ethylaluminum dichloride, and n-propylaluminum dichloride, (b) Alkylaluminum sesquihalides, specifically ethylaluminum sesquichloride, (ha) dialkylaluminum halides, specifically dimethylaluminum chloride, diethylaluminum chloride, di-n-propylaluminum chloride, and diethylaluminum bromide, ) Trialkylaluminum, specifically, trimethylaluminum, triethylaluminum, and triisobutylaluminum, (e) dialkylaluminum Um hydride, specifically, it may be mentioned diethyl aluminum hydride and the like. Here, “alkyl” is lower alkyl such as methyl, ethyl, propyl, butyl and the like. The “halide” is chloride or bromide, and the former is particularly common.

  The reduction reaction with an organoaluminum compound to obtain titanium trichloride is usually carried out in the temperature range of −60 to 60 ° C., preferably −30 to 30 ° C. The reduction reaction is preferably performed in an inert hydrocarbon solvent such as pentane, hexane, heptane, octane and decane.

Furthermore, it is preferable that the titanium trichloride obtained by the reduction reaction of titanium tetrachloride with an organoaluminum compound is further subjected to ether treatment and electron acceptor treatment.
Examples of the ether compound preferably used in the ether treatment of titanium trichloride include diethyl ether, di-n-propyl ether, di-n-butyl ether, diisoamyl ether, dineopentyl ether, di-n-hexyl ether, di- Examples include ether compounds in which each hydrocarbon residue is a chain hydrocarbon having 2 to 8 carbon atoms, such as n-octyl ether, di-2-ethylhexyl ether, methyl-n-butyl ether, and ethyl-isobutyl ether. Among them, it is particularly preferable to use di-n-butyl ether.

  As the electron acceptor used in the treatment of titanium trichloride, halogen compounds of elements of Group III to Group IV and Group VIII of the periodic table are preferable. Specifically, titanium tetrachloride, silicon tetrachloride, three Examples thereof include boron fluoride, boron trichloride, antimony pentachloride, gallium trichloride, iron trichloride, tellurium dichloride, tin tetrachloride, phosphorus trichloride, phosphorus pentachloride, vanadium tetrachloride, and zirconium tetrachloride. When preparing the solid catalyst component, the treatment with the ether compound of titanium trichloride and the electron acceptor may be performed using a mixture of both treatment agents, or after the treatment with one, the treatment with the other may be performed. Good. Among these, the latter is preferable, and it is more preferable to perform the electron acceptor treatment after the ether treatment.

  It is generally desirable to wash the titanium trichloride with a hydrocarbon prior to treatment with the ether compound and electron acceptor. The ether treatment of titanium trichloride is performed by bringing the titanium trichloride into contact with the ether compound. The treatment of titanium trichloride with an ether compound is advantageously performed by bringing both into contact in the presence of a diluent. As such a diluent, it is preferable to use an inert hydrocarbon compound such as hexane, heptane, octane, decane, benzene and toluene.

The amount of the ether compound used is generally in the range of 0.05 to 3.0 mol, preferably 0.5 to 1.5 mol, per 1 mol of titanium trichloride. Strictly speaking, titanium trichloride treated with an organoaluminum compound or an ether compound is a composition mainly composed of titanium trichloride.
As such a solid catalyst component, Solvay type titanium trichloride can be suitably used.

  Examples of the organoaluminum compound used together with the solid catalyst component include the same compounds as described above.

  The production method of this polypropylene is preferably a slurry polymerization method. The polymerization method may be performed in a single stage or in multiple stages. The structure is not particularly limited, and examples thereof include homopolypropylene, block polypropylene, random polypropylene, and random block polypropylene.

  By using a catalyst system composed of an organoaluminum compound and a titanium trichloride composition in the production of this polypropylene resin, the molecular weight distribution is broader than that of a catalyst system composed of an organomagnesium compound and a titanium tetrachloride composition. Polypropylene with a high content can be obtained.

  The proportion of component (B) in the resin composition of the present invention is 5 to 90% by weight, preferably 60 to 85% by weight. If it exceeds 90% by weight, the foaming characteristics are lowered, which is not preferable. On the other hand, less than 5% by weight is not preferable because the cost cannot be reduced.

(C) Inorganic filler As (C) component inorganic filler (hereinafter referred to as (C) component), talc, silica, calcium carbonate, clay, zeolite, alumina, barium sulfate, magnesium hydroxide and the like can be mentioned. Of these, talc is preferred because it provides a good balance between the appearance of the sheet and the mechanical properties. A suitable average particle diameter (measured by a laser method) of talc is 30 μm or less.

  The proportion of component (C) in the resin composition of the present invention is 5 to 25% by weight, preferably 10 to 20% by weight. If the filling amount is less than 5%, the contribution to the rigidity of the container is small, which is not preferable. On the other hand, if it exceeds 25%, the weight of the container becomes heavy and foam breakage occurs, resulting in poor heat insulation.

  The resin composition of this invention can contain another component in the range which does not impair the effect. The composition of the present invention can contain additives such as an antioxidant, a neutralizing agent, a flame retardant, and a crystal nucleating agent as necessary.

  The composition of the present invention can be produced by mixing each component by a usual method such as dry blending or melt-kneading in an extruder. The composition of the present invention can be formed into a sheet by foaming with a T-die after mixing the components. Further, the foamed sheet can be further thermoformed to obtain a molded body. The obtained molded body can be used for containers, stationery, returnable boxes and the like.

The foamed sheet is obtained by, for example, melting and kneading the polypropylene resin and the foaming agent as described above in an extruder, and then extruding and foaming the melt-kneaded product from a T die attached to the tip of the extruder. Manufactured.
In obtaining a foamed sheet from the resin composition of the present invention, additives such as a crystal nucleating agent, an ultraviolet absorber, an antioxidant, an antistatic agent, and a coloring agent can be added as necessary.

The molded body formed by foam molding of the composition of the present invention preferably satisfies the following (1) and (2).
(1) Average cell diameter is 500 μm or less (2) Open cell ratio is 1 to 30%
A foamed molded article satisfying the above (1) and (2) is preferable because it is excellent in heat insulation and container appearance. The average cell diameter can be adjusted by the type and addition amount of the foaming agent, the expansion ratio, and the like. A foam-molded composition of the present invention easily satisfies these conditions.

In obtaining the foamed sheet or other molded article of the present invention, an inorganic foaming agent, a volatile foaming agent, a decomposable foaming agent, or the like can be used as the foaming agent.
Examples of the inorganic foaming agent include carbon dioxide, air, and nitrogen. Examples of volatile blowing agents include propane, n-butane, i-butane, a mixture of n-butane and i-butane, chain aliphatic hydrocarbons such as pentane and hexane, and cyclic aliphatic carbonization such as cyclobutane and cyclopentane. Hydrogen etc. are mentioned. Examples of the decomposable foaming agent include azodicarbonamide, dinitrosopentamethylenetetramine, azobisisobutyronitrile, sodium bicarbonate and the like. These foaming agents can be mixed and used as appropriate.

  The foamed molded product of the present invention can be further thermoformed. As a thermoforming method, a general vacuum forming method, a pressure forming method, a vacuum pressure forming method, or the like is used. Thermoformed bodies obtained by these molding methods can be used in food containers, electronic material trays, and the like.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, measurement and evaluation of various properties of the resin and molded body obtained in each example were performed as follows.
(1) Melt tension (MT [unit: g])
Measurement was performed at a take-up speed of 3.1 m / min using a Capillograph 1C manufactured by Toyo Seiki Co., Ltd. The measurement temperature was 230 ° C for component (A) and 190 ° C for component (B).
For the measurement, an orifice having a length of 8 mm and a diameter of 2.095 mm was used.

(2) Molecular weight distribution (Mw / Mn) and Z average molecular weight (Mz)
The molecular weight distribution (Mw / Mn) was calculated from Mw and Mn in terms of propylene polymer measured by the gel permeation chromatography (GPC) method using the following apparatus and conditions. Mz was obtained by the same measurement.
GPC measurement device Column: TOSOGMMHHR-H (S) HT
Detector: RI detector for liquid chromatogram WATERS150C
Measurement conditions Solvent: 1,2,4-trichlorobenzene Temperature: 145 ° C

(3) Melt flow rate (MFR) (Unit: g / 10 min)
Based on JIS-K7210, the measurement was performed at a measurement temperature of 230 ° C. and a load of 2.16 kg.
(4) Relaxation time τ (unit: seconds)
A polypropylene resin was compression-molded by pressing at 220 ° C. for 3 minutes so as not to contain air bubbles, and a disk-shaped measurement sample having a thickness of 1 mm and a diameter of 25 mm was produced. For this sample, a rotational rheometer manufactured by Rheometrics, using a cone plate of 25 mmφ, a cone angle of 0.10 radians, a frequency dispersion of 0.01 to 100 rad / s at a temperature of 175 ° C. and a strain of 5%. The relaxation time τ at the angular frequency ω ₀ = 0.1 rad / sec when the measurement was performed was determined.
That is, the measured complex elastic modulus G ^{* (iω),} when defined in σ ^{* / γ *} by stress sigma ^* and strain gamma ^*, the following equation was determined.
G ^* (iω) = σ ^* / γ ^* = G ′ (ω) + iG ″ (ω)
τ (ω) = G ′ (ω) / ωG ″ (ω)
(Here, G ′ represents the storage elastic modulus and G ″ represents the loss elastic modulus.)

(5) Foaming ratio The specific gravity was calculated by dividing the weight of the obtained foamed sheet by the volume determined by the underwater substitution method, and the foaming ratio was calculated.
(6) Open cell ratio (%)
It measured using the air comparison type hydrometer 1000 type | mold (made by Tokyo Science).
(7) Sheet appearance The sheet surface was visually observed.
○ Excellent smoothness, △ Smoothness is slightly bad, × Smoothness is bad

(8) Thermoformability The shape of the tray obtained by vacuum forming using a tray mold was visually observed with a vacuum pressure thermoforming machine FK-0431-10 (manufactured by Asano Laboratories). The indirect heating temperature was 500 ° C. (up and down).
○ Excellent mold reproducibility, △ Mold reproducibility is somewhat poor, × Mold reproducibility is poor Mold reproducibility means that the container shape is the same as the mold.
When the open cell ratio is high, the bubble breakage progresses at the time of thermoforming, and at the time of shaping, the thickness becomes non-uniform when the sheet is stretched and the required container shape cannot be obtained.
(9) Average cell diameter Using a scanning electron microscope JSM-6100 (manufactured by JEOL Ltd.), observe the cross section of the sheet at a magnification of 70 times, and measure the diameter of 100 cells in the screen to obtain the average value. It was.

The following ingredients were used in each example.
Component (A): The following four types of resins were used.
(1) FB3312 (manufactured by JPP) (high molecular weight prepolymer)
(2) PF-814 (manufactured by Sun Allomer) (cross-linked electron beam)
(3) Silane-crosslinked polypropylene (Production Example 1)
(4) Propylene-based graft polymer (Production Example 2)

(B) Component The polypropylene produced in Production Examples 3 to 8 was used.

Component (C) Talc (Asada Flour Milling Co., Ltd., trade name JA-80R, average particle diameter measured by laser method is 10 μm)

Production Example 1: Silane-crosslinked polypropylene (component (A))
It was produced by the method described in Japanese Patent Application No. 2004-160665.

Production Example 2: Propylene-based graft polymer (component (A))
It was produced by the method described in Japanese Patent Application No. 2004-160665.

Production Example 3: Al-Ti catalyst system MFR7 (component (B))
(Preliminary polymerization)
A three-necked flask equipped with a stirrer with an internal volume of 5 liters was thoroughly dried and replaced with nitrogen gas, 4 liters of dehydrated heptane and 140 grams of diethylaluminum chloride were added, and the solid catalyst component (commercially available Solvay type trichloride) was added. 20 g of titanium catalyst (manufactured by Tosoh Finechem) was added. The internal temperature was kept at 20 ° C., and propylene was continuously introduced while stirring. After 80 minutes, stirring was stopped, and as a result, a prepolymerized catalyst component in which 0.8 g of propylene was polymerized per 1 g of the solid catalyst was obtained.

(Propylene polymerization)
A stainless steel autoclave with a stirrer with an internal volume of 10 liters was sufficiently dried and replaced with nitrogen gas, 6 liters of dehydrated heptane was added, and nitrogen in the system was replaced with propylene. Thereafter, the internal temperature was set to 60 ° C., 0.078 MPa of hydrogen was added, and propylene was introduced while stirring. After the system was stabilized at a total pressure of 0.78 MPa and 60 ° C., 150 ml of heptane slurry containing 0.75 g of the above prepolymerized catalyst component in terms of solid catalyst was added to initiate polymerization. After continuously supplying propylene for 4 hours from the start of polymerization, 50 ml of methanol was added to complete the polymerization, and the temperature was lowered and the pressure was released. The entire contents were transferred to a filtration tank with a filter, 100 ml of 1-butanol was added, and the mixture was stirred at 85 ° C. for 1 hour, followed by solid-liquid separation. Further, the solid part was washed twice with a mixed solution of 5 liters of heptane at 85 ° C. and 1 liter of distilled water, and vacuum dried to obtain 3.8 kg of a propylene polymer. The intrinsic viscosity [η] of this polymer measured in 135 ° C. tetralin was 1.87 dl / g.

To 100 parts by weight of the resulting propylene polymer, 0.1 parts by weight of Irganox 1010 as an antioxidant, 0.1 parts by weight of Irgafos 168 and 0.1 parts by weight of calcium stearate as a neutralizer are added and stirred. Thorough mixing was performed. Next, granulation (melt kneading) was performed using a TEM35B twin screw extruder (manufactured by Toshiba Machine) at a cylinder temperature of 200 ° C. and an extrusion rate of 30 kg / hr.
This polypropylene had an MT of 2.0 g, an MFR of 7.1 g / 10 min, τ of 3.4 seconds, a molecular weight distribution Mw / Mn of 6.7, and a Z average molecular weight (Mz) of 1.31 million.

Production Example 4: Al-Ti catalyst system MFR3 (component (B))
A stainless steel autoclave with a stirrer with an internal volume of 10 liters was sufficiently dried and replaced with nitrogen gas, 6 liters of dehydrated heptane was added, and nitrogen in the system was replaced with propylene. Thereafter, the internal temperature was 70 ° C., 0.069 MPa of hydrogen was added, and propylene was introduced while stirring. After the system was stabilized at a total pressure of 0.74 MPa and 70 ° C., 100 ml of a heptane slurry containing 0.50 g of the prepolymerized catalyst component produced in Production Example 3 in terms of solid catalyst was added to initiate polymerization. After continuously supplying propylene for 4 hours from the start of the polymerization, 50 ml of methanol was added to complete the polymerization, and the temperature was lowered and the pressure was released. The entire contents were transferred to a filtration tank with a filter, 100 ml of 1-butanol was added, and the mixture was stirred at 85 ° C. for 1 hour, followed by solid-liquid separation. Further, the solid part was washed twice with a mixed solution of 5 liters of heptane at 85 ° C. and 1 liter of distilled water, and vacuum dried to obtain 3.1 kg of a propylene polymer. The intrinsic viscosity [η] of this polymer measured in 135 ° C. tetralin was 2.04 dl / g. Various properties of the obtained polypropylene were measured in the same manner as in Production Example 3, and the results are shown in Table 1.

Production Example 5: Al-Ti catalyst system MFR9 (component (B))
The same procedure as in Production Example 3 was carried out except that the initial hydrogen tension was changed to 0.098 MPa in Production Example 3 to obtain 3.8 kg of a propylene polymer. This polymer had an intrinsic viscosity [η] measured in 135 ° C. tetralin of 1.66 dl / g. Various properties of the obtained polypropylene were measured in the same manner as in Production Example 3, and the results are shown in Table 1.

Production Example 6: Al-Ti catalyst system MFR4 (component (B))
The same procedure as in Production Example 3 was carried out except that the initial hydrogen tension was changed to 0.072 MPa in Production Example 3 to obtain 3.7 kg of a propylene polymer. The intrinsic viscosity [η] of this polymer measured in 135 ° C. tetralin was 1.98 dl / g. Various properties of the obtained polypropylene were measured in the same manner as in Production Example 3, and the results are shown in Table 1.

Production Example 7: Mg-Ti catalyst system MFR7 (component (B))
(Preparation of solid catalyst component)
160 g (1.4 mol) of diethoxymagnesium was charged into a three-neck flask with a stirrer having an internal volume of 5 liters substituted with nitrogen, and 500 ml of dehydrated heptane was further added. The mixture was heated to 40 ° C., 28.5 ml (225 mmol) of silicon tetrachloride was added, stirred for 20 minutes, and 127 mmol of diethyl phthalate was added. The temperature of the solution was raised to 80 ° C., and subsequently 461 ml (4.2 mol) of titanium tetrachloride was added dropwise using a dropping funnel. The internal temperature was set to 110 ° C. and the mixture was stirred for 2 hours to carry out the supporting operation. Thereafter, it was thoroughly washed with dehydrated heptane. Further, 768 ml (7 moles) of titanium tetrachloride was added, the internal temperature was set to 110 ° C., and the mixture was stirred for 2 hours to carry out the second loading operation. Thereafter, it was thoroughly washed with dehydrated heptane to obtain a solid catalyst component.

(Preliminary polymerization)
A heptane slurry containing 60 g (37.6 mmol-Ti) of the above solid catalyst component was put into a three-necked flask with a stirrer having an internal volume of 1 liter substituted with nitrogen, and dehydrated heptane was further added, It was 500 ml. This was stirred while controlling at 40 ° C., and 24.8 mmol of triethylaluminum and 6.2 mmol of cyclohexyldimethoxysilane were added. While maintaining the temperature at 40 ° C., a predetermined amount of propylene was absorbed for 120 minutes, the remaining propylene was replaced with nitrogen, and washed thoroughly with heptane to obtain 85 grams of a prepolymerized catalyst component (sealing amount: 0.43 grams − Polypropylene / gram solid Ti catalyst component).

(Propylene polymerization)
A stainless steel autoclave with a stirrer with an internal volume of 10 liters was sufficiently dried, and after substitution with nitrogen, 6 liters of dehydrated heptane were added. The autoclave temperature was warmed to 80 ° C. and 12 mmol of triethylaluminum was added followed by 1.2 mmol of cyclohexylmethyldimethoxysilane. Next, after introducing 0.03 MPa of hydrogen, propylene was introduced to make the total pressure 0.78 MPa. After the system was stabilized, 0.3 mmol of the above prepolymerized catalyst component per Ti was added to initiate polymerization. After 1 hour, 50 ml of methanol was charged into the system to complete the polymerization, and the temperature was lowered and the pressure was released. The contents were taken out, filtered, and dried for 12 hours under a dry nitrogen stream at 70 ° C. to obtain 2.4 kg of a propylene polymer. This polymer had an intrinsic viscosity [η] measured in 135 ° C. tetralin of 1.68 dl / g. Various properties of the obtained polypropylene were measured in the same manner as in Production Example 3, and the results are shown in Table 1.

Example 1
100 parts by weight of a pellet blend comprising 20% by weight of FB3312 as component (A), 70% by weight of polypropylene obtained from Production Example 3 as component (B), and 10% of talc as component (C) 0.4 parts by weight of a foaming agent (EE205, manufactured by Eiwa Kasei Kogyo Co., Ltd.) was dry blended. As the foam molding machine, TEM-41SS manufactured by Toshiba Machine Co., Ltd. was used. Molding was performed at a screw rotation speed of 100 rpm, a cylinder temperature of 210 ° C., a die temperature of 180 ° C., and a carbon dioxide injection rate of 120 g / hr. Regarding the foamed sheet obtained at a take-up speed of 2.5 m / min, the sheet surface appearance was visually observed. The expansion ratio was about 2 times. Further, the open cell ratio and average cell diameter of the obtained sheet were measured. Furthermore, thermoforming was performed using the obtained foamed sheet, and mold reproducibility was evaluated.

Example 2
(B) It carried out like Example 1 except having changed the component into the polypropylene of manufacture example 6. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 3
The same procedure as in Example 1 was performed except that PF-814 was changed to 10% by weight as the component (A), the polypropylene of Production Example 3 was changed to 75% by weight and the amount of talc was changed to 15% by weight as the component (B). The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 4
The same procedure as in Example 3 was performed except that the amount of each component in Example 3 was changed as shown in Table 2. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 5
(B) It carried out like Example 1 except having changed the component into the polypropylene of manufacture example 5. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 6
The same procedure as in Example 1 was performed except that the blending amounts of the components (B) and (C) were changed as shown in Table 2. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Examples 7 and 8
(A) It carried out like Example 1 except having changed the component into manufacture example 1 and the compounding quantity as shown in Table 2. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 9
(A) It carried out like Example 1 except having changed the component into manufacture example 2 and the compounding quantity as shown in Table 2. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 1
The same procedure as in Example 1 was performed except that the component (B) was changed to the polypropylene of Production Example 3 without using the component (A) and the blending amount was changed as shown in Table 2. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 2
The same procedure as in Example 1 was performed except that the component (B) was changed to the polypropylene of Production Example 4 and the blending amount was changed as shown in Table 2 without using the component (A). The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 3
(B) It carried out like Example 1 except having changed the component into the polypropylene of manufacture example 7. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 4
(B) It carried out like Example 1 except having changed the component into the polypropylene of manufacture example 4. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 5
In Example 3, it carried out like Example 3 except having changed the compounding quantity of Example 3 as shown in Table 2. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 6
In Example 7, it carried out like Example 7 except having changed (B) component into the polypropylene of manufacture example 7. FIG. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 7
In Example 9, it carried out like Example 9 except having changed the (B) component into the polypropylene of the manufacture example 7. The obtained foamed sheet was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

The foamed molded article obtained by the present invention is excellent in heat insulation, heat resistance and oil resistance, and can be suitably used as a food container, particularly a microwave oven container (tray, bowl, cup, etc.).

Claims (8)

A polypropylene resin composition for foam molding with a T-die comprising the following components (A), (B) and (C).
(A) Polyolefin component having a melt tension of 5 to 30 g at 230 ° C .: 5 to 40% by weight
(B) Polypropylene resin satisfying the following (1) to (4): 5 to 90% by weight
(1) Melt tension at 190 ° C. is 1.5 to 7.0 g
(2) Melt flow rate is 3 to 10 g / 10 min. (3) Ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) is 5 to 8, Z average molecular weight (Mz) is 950,000. ˜2 million (4) In melt viscoelastic behavior measured using a rotational rheometer, the relaxation time (τ) at an angular frequency ω = 0.1 rad / sec is 2 to 7 seconds (C) Inorganic filler: 5 25% by weight   Component (A) was obtained by producing a propylene polymer in the polymerization step in the presence of a pre-activated catalyst in which an ultrahigh molecular weight ethylene polymer was supported on a polymerization catalyst, and subsequently producing an olefin polymer. 2. The polypropylene resin composition for foam molding according to claim 1, which is an olefin multistage polymer.   The polypropylene resin composition for foam molding according to claim 1, wherein the component (A) is a polypropylene resin into which long chain branches obtained by irradiating ionizing radiation are introduced.   The polypropylene resin composition for foam molding according to claim 1, wherein the component (A) is a propylene polymer composition obtained by contacting a polypropylene resin, an organosilicon compound and a high molecular weight acid-modified α-olefin polymer. .   Component (A) is a polymerization or copolymerization of one or more monomers selected from ethylene, propylene, α-olefins having 4 to 20 carbon atoms, styrenes and cyclic olefins by a two-stage polymerization method in the presence of polyene. The polypropylene resin composition for foam molding according to claim 1, which is a polyolefin resin obtained by allowing the resin to be foamed.   (B) A catalyst comprising a solid catalyst component obtained by treating a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound with an ether and an electron acceptor and an organoaluminum compound as essential components The polypropylene resin composition for foam molding according to any one of claims 1 to 5, which is a polypropylene resin obtained by polymerizing propylene in the presence of.   The polypropylene resin composition for foam molding according to any one of claims 1 to 6, wherein the component (C) is talc having an average particle size of 30 µm or less as measured by a laser method. The foaming molding which satisfy | fills following (1) and (2) obtained by foam-molding the polypropylene resin composition for foam-molding as described in any one of Claims 1-7.
(1) Average cell diameter is 500 μm or less (2) Open cell ratio is 1 to 30%