JP2009241517A - Polypropylene based extrusion foamed article, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene based extrusion foamed article which can be manufactured by using a conventional extrusion-foaming apparatus, and has a high foaming magnification and a favorable surface appearance, and to provide its manufacturing method. <P>SOLUTION: After meltingly kneading a mixture containing a polypropylene based resin and a foaming material in an extruder, the mixture is extrusion-foamed from a die 150 to obtain an extrusion-foamed body. Then, the extrusion foamed article is molded before being crystallized, and solidified by cooling and this polypropylene based extrusion foamed article of a specified dimension is formed. The polypropylene based resin satisfies the following A and B, and when being extrusion foamed in a low pressure region, the nominal shear rate on the die wall surface at an area in a vicinity of the die outlet, and where the die clearance becomes minimum is from 10 s<SP>-1</SP>to 1,000 s<SP>-1</SP>, and the foaming magnification is 3 times or more. (A) By a capillary flow test with conditions of the measurement temperature at 210°C, and the shear rate at 1216 s<SP>-1</SP>, the pressure compensating value in the bar gray compensation is 4 MPa or higher. (B) The melt flow rate (MFR) is 0.5 g/10 minutes or higher. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polypropylene-based extruded foam molded body and a method for producing the same.

Conventionally, resin foam moldings are frequently used for the interior and exterior of automobiles and the interior and exterior of buildings such as houses. For example, in automobiles, boards and panels using resin foam moldings are used for interiors such as ceilings, doors, and floors facing indoor spaces, and exteriors such as cowls and bodies. Also, in housing facilities, resin foam molded bodies are used as building materials such as heat insulation boards for houses.
Polystyrene or the like has been used as a material for such a resin foam molding, but a polypropylene resin is suitable from the viewpoint of heat resistance, chemical resistance, and light weight.

However, since the polypropylene-based resin is inferior in foam moldability as compared with polystyrene, it is difficult to stably supply an extruded foam molded article having a foaming ratio exceeding 3 times in extrusion foam molding. In particular, linear polypropylene was poor in strain hardening of elongational viscosity, and adjacent bubble walls were easily broken in the foam molding process.
In view of this, a material has been developed in which a branched structure is imparted to the molecular chain of polypropylene to develop a high melt tension and to improve foam moldability (see, for example, Patent Document 1).

In addition, by optimizing the molecular weight and quantity ratio of the ultra-high molecular weight component, a polypropylene resin composition was invented that made it difficult to break the cell walls by generating a large extensional viscosity in the high-speed extension flow field of the bubble formation process. (For example, refer to Patent Document 2).
And according to the said polypropylene resin composition, the high foaming whose foaming magnification exceeds 10 times is obtained by the extrusion foaming molding using a supercritical carbon dioxide (for example, patent document 3).

On the other hand, in extrusion foam molding with polypropylene resin, the flow area at the die outlet is reduced so that sudden pressure reduction occurs at the die outlet in order to prevent foam destruction at the upstream of the die and the flow process after foaming. There is a need. For example, an extruded foam is disclosed in which a predetermined polypropylene resin is foamed at a shear rate of 600 s ⁻¹ or more on the die exit wall surface (see, for example, Patent Document 4).

Japanese Examined Patent Publication No. 7-45551 JP 2007-119760 A WO2006 / 118160 Japanese Patent Laid-Open No. 9-40796

  However, in Patent Document 1, since the polymer having a branched structure is easily broken, the viscoelastic property may be changed in the flow process in extrusion molding. In addition, there is a problem that a polymer having a branched structure is not suitable for recycling. In addition, because of the branched structure, it is effective for improving the drawability of the sheet by increasing the rise of the extension viscosity at a low strain rate, but it is effective for extension deformation under high speed that contributes to the destruction of bubbles. However, good characteristics were not always obtained.

In Patent Documents 2 and 3, although a high foam having a foaming ratio exceeding 10 times can be obtained, there is a problem that it is necessary to supply a large amount of a foaming agent at a high pressure, and the cost of capital investment becomes enormous.
And although the extrusion foam of patent document 4 has the closed cell rate of 60% or more, extrusion at a high shear rate was required.

  Further, when the flow path area at the die outlet is reduced, the shear rate of the die wall surface increases, melt fracture is likely to occur, and defective phenomena such as corrugated marks are likely to occur. That is, there exists a problem that the appearance defect of a foam tends to arise.

  An object of the present invention is to provide a polypropylene-based extruded foam molded article that can be produced using a conventional extrusion foaming apparatus and has a relatively high foaming ratio and good surface appearance, and a method for producing the same.

The method for producing a polypropylene-based extruded foamed product of the present invention includes a melt-kneading step in which a mixture containing a polypropylene-based resin and a foamed material is melt-kneaded in an extruder, and a composition melt-kneaded in this melt-kneading step. An extrusion foaming process for forming an extruded foam by extrusion foaming, and a mold molding process for producing a polypropylene-based extruded foam molding of a predetermined shape by molding the extruded foam formed in this extrusion foaming process The polypropylene resin is a pressure in Burgley correction in a capillary flow test under the conditions of (A) measurement temperature 210 ° C. and shear rate 1216 s ^−1. The correction value is 4 MPa or more, and (B) the melt flow rate (MFR) is 0.5 g / 10 min or more. In the process, the foamed material is contained in the polypropylene-based resin under the condition that the expansion ratio of the extruded foamed product is 3 times or more, and at least the inside of the extruded foamed product is crystallized in the mold forming step. Is molded by the mold, cooled and solidified, and then demolded to produce the polypropylene-based extruded foamed article.
Here, the capillary flow test is performed based on the provisions of “flow characteristic test method using capillary rheometer (JIS K 7199)”.
The shear rate here represents an apparent shear rate and can be determined from the diameter and flow rate of the capillary die.
The pressure correction value in the Bargley correction is the sum of pressure losses at the inlet and outlet of the capillary die. It is obtained by setting a plurality of ratios (L / D) of the diameter D of the capillary die and the length L of the capillary die and performing each test. When this pressure correction value is large, it indicates that the inlet pressure loss is large, and the resistance against the reduced flow at the inlet is large. That is, the elongational viscosity is large.

Specifically, for example, the pressure correction value is set by setting three types: a barrel diameter of 9.55 mm, a capillary die diameter of 1.0 mm, a capillary die inflow angle of 90 °, and an L / D of 30, 40, and 50. Can be sought. However, the present invention is not limited to these values, and it is sufficient that the inflow angle is 90 ° or more and the ratio of the diameter of the barrel and the capillary die is 8 or more.
When there is no measurement value at a shear rate of 1216S ^-1, by interpolation using the data of the pressure correction value at a shear rate of the upper and lower two adjacent points of the shear rate, the pressure at a shear rate of 1216S ^-1 A correction value may be calculated.

According to this invention, the polypropylene resin, which is the material of the polypropylene-based extruded foam molding, has a pressure correction value at a high shear rate of 1216 s ⁻¹ of 4 MPa or more, so that it is as high as when bubbles are formed. It can be said that the elongational viscosity is high under speed. That is, the bubbles are difficult to break. Therefore, a polypropylene-based extruded foam having a foaming ratio of 3 times or more is obtained, and before the extruded foam is cooled and crystallized, the foaming ratio does not change substantially and the predetermined mold is used. The mold can be molded into a shape, and the expansion of the use of the polypropylene-based extruded foam molding can be easily obtained.

Further, the melt flow rate (MFR) of the polypropylene resin was set to 0.5 g / 10 min or more. When the MFR is less than 0.5 g / 10 min, the fluidity of the resin is poor and the productivity is poor. That is, when the MFR of the resin is 0.5 g / 10 min or more, the production with an extruder can be easily performed. A more preferable range of MFR is 1 g / 10 min or more and 10 g / 10 min or less.
In addition, it should be noted that when the MFR exceeds 100 g / 10 min, the melt tension and viscosity of the polypropylene resin become low, and extrusion foaming may be difficult.

  As the polypropylene resin satisfying the above properties, a propylene-based multistage polymer, a propylene homopolymer, a copolymer of propylene and another olefin, or a blend of these is used.

The propylene-based multistage polymer includes the following component (P1) and component (P2).
(P1) A propylene homopolymer component having an intrinsic viscosity [η] of more than 10 dL / g measured in a tetralin solvent at 135 ° C. or a copolymer component of propylene and an α-olefin having 2 to 8 carbon atoms, 5-20 mass% is contained in the polymer.
(P2) Copolymerization of propylene homopolymer component having intrinsic viscosity [η] measured in tetralin solvent at 135 ° C. of 0.5 to 3.0 dL / g or propylene and α-olefin having 2 to 8 carbon atoms The coalescence component is contained in the total polymer in an amount of 80 to 95% by mass.
This propylene-based multistage polymer achieves a high melt tension by adding component (P1), that is, an ultrahigh molecular weight propylene polymer, and a linear propylene-based polymer whose viscoelastic properties are adjusted by adjusting the molecular weight distribution. It is a coalescence.

When the intrinsic viscosity of the component (P1) is 10 dL / g or less, the melt tension becomes insufficient and the desired foaming performance may not be obtained. Moreover, when the mass fraction of a component (P1) is smaller than 5 mass%, melt tension will become inadequate and desired foaming performance may not be obtained. On the other hand, if the mass fraction exceeds 20% by mass, so-called melt fracture may become severe, which may cause rough skin of the extruded foam and the product quality will be reduced.
As described above, the intrinsic viscosity of component (P1) is preferably more than 10 dL / g, more preferably in the range of 12 to 30 dL / g, and in the range of 13 to 18 dL / g. Is particularly preferred.
Moreover, it is preferable that the mass fraction of a component (P1) exists in the range of 8-18 mass%, and it is especially preferable that it exists in the range of 10-16 mass%.

When the intrinsic viscosity of the component (P2) is less than 0.5 dL / g, the melt tension becomes insufficient and the desired foaming performance may not be obtained. On the other hand, if it exceeds 3.0 dL / g, the viscosity is too high and a suitable extruded foam may not be formed.
Further, when the mass fraction of the component (P2) is less than 80% by mass, it may be difficult to carry out suitable foam molding. When the mass fraction exceeds 95% by mass, the melt tension becomes low. However, it may be difficult to form a suitable extruded foam.
The intrinsic viscosity of component (P2) is preferably in the range of 0.5 to 3.0 dL / g as described above, but more preferably in the range of 0.8 to 2.0 dL / g. More preferably, it is in the range of 1.0 to 1.5 dL / g.
Moreover, it is preferable that the mass fraction of a component (P2) exists in the range of 82-92 mass%, and it is especially preferable that it exists in the range of 84-90 mass%.

In the propylene-based multistage polymer used in the present embodiment, examples of the α-olefin having 2 to 8 carbon atoms constituting the copolymer component include ethylene and 1-butene which are α-olefins other than propylene. . Among these, it is preferable to use ethylene.
In the propylene-based multistage polymer, the relationship between the melt flow rate (MFR) at 230 ° C. and the melt tension (MT) at 230 ° C. preferably satisfies the following formula (I).

    log (MT)> − 1.33 log (MFR) +1.2 (I)

Here, when the relationship between the melt flow rate (MFR) at 230 ° C. and the melt tension (MT) at 230 ° C. does not satisfy the formula (I), it is difficult to perform extrusion foaming at a high magnification. It may become. The constant (1.2) is preferably 1.3 or more, and particularly preferably 1.4 or more.
In addition, what is necessary is just to make it contain 5-20 mass% of components (P1) so that a propylene type multistage polymer may have the relationship of above-mentioned Formula (I).

  In addition, the propylene-based multistage polymer has a storage elastic modulus slope on a high frequency side as a certain amount or more as dynamic viscoelasticity in a molten state (relation between angular frequency ω and storage elastic modulus G ′). Specifically, specifically, the storage elastic modulus G ′ (10) when the angular frequency is 10 rad / s (radians / second) and the storage elastic modulus G ′ (1) when the angular frequency is 1 rad / s. G ′ (10) / G ′ (1) is preferably 2.0 or more, and particularly preferably 2.5 or more. If this ratio G ′ (10) / G ′ (1) is smaller than 2.0, stability may be reduced when an external change such as stretching is applied to the extruded foam.

  Similarly, the propylene-based multistage polymer preferably has a storage elastic modulus slope on the low frequency side as a dynamic viscoelasticity in a molten state having a certain amount or less, specifically, an angular frequency. Is the ratio of the storage elastic modulus G ′ (0.1) when the angular frequency is 0.1 rad / s and the storage elastic modulus G ′ (0.01) when the angular frequency is 0.01 rad / s. 0.1) / G ′ (0.01) is preferably 6.0 or less, and particularly preferably 4.0 or less. If the ratio G ′ (0.1) / G ′ (0.01) exceeds 6.0, it may be difficult to increase the expansion ratio of the extruded foam under a low shear rate.

  Such a propylene-based multistage polymer uses an olefin polymerization catalyst composed of the following components (a) and (b) or the following components (a), (b) and (c) in a polymerization process of two or more stages. It can be produced by polymerizing propylene or copolymerizing propylene and an α-olefin having 2 to 8 carbon atoms.

(A) Solid catalyst component obtained by treating titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound with an ether compound and an electron acceptor (b) Organoaluminum compound (c) Cyclic ester compound

  In the solid catalyst component (a), as the organoaluminum compound for reducing titanium tetrachloride, for example, (a1) alkylaluminum dihalide, specifically, methylaluminum dichloride, ethylaluminum dichloride, and n-propylaluminum dichloride, (A2) alkylaluminum sesquihalide, specifically ethylaluminum sesquichloride, (a3) dialkylaluminum halide, specifically, dimethylaluminum chloride, diethylaluminum chloride, di-n-propylaluminum chloride, and diethylaluminum bromide (A4) trialkylaluminum, specifically, trimethylaluminum, triethylaluminum, and triisobutylaluminum, (a5) Alkylaluminum hydride, specifically, 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 for obtaining titanium trichloride is usually carried out in the temperature range of −60 to 60 ° C., preferably −30 to 30 ° C. If the temperature in the reduction reaction is lower than −60 ° C., a long time is required for the reduction reaction. On the other hand, if the temperature in the reduction reaction exceeds 60 ° C., excessive reduction may occur in some cases. The reduction reaction is preferably carried out in an inert hydrocarbon solvent such as pentane, heptane, octane and decane.

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, for example, diethyl ether, di-n-propyl ether, di-n-butyl ether, diisoamyl ether, dineopentyl ether, di-n-hexyl ether, Examples include ether compounds in which each hydrocarbon residue is a chain hydrocarbon having 2 to 8 carbon atoms such as di-n-octyl ether, di-2-ethylhexyl ether, methyl-n-butyl ether and ethyl-isobutyl ether. Of these, di-n-butyl ether is particularly preferred.

  As the electron acceptor used in the treatment of titanium trichloride, it is preferable to use halogen compounds of elements of Group III to Group IV and Group VIII of the Periodic Table. Specifically, titanium tetrachloride, Examples include silicon chloride, boron trifluoride, boron trichloride, antimony pentachloride, gallium trichloride, iron trichloride, tellurium dichloride, tin tetrachloride, phosphorus trichloride, phosphorus pentachloride, vanadium tetrachloride and zirconium tetrachloride. be able to.

  When preparing the solid catalyst component (a), the treatment with the ether compound of titanium trichloride and the electron acceptor may be performed using a mixture of both treatment agents, and after the treatment with one treatment agent, the other You may make it perform the process by the processing agent of. Of these, the latter is preferred, and treatment with an electron acceptor is further preferred after ether treatment.

  Prior to treatment with the ether compound and electron acceptor, it is preferred to wash the titanium trichloride with a hydrocarbon. The above-mentioned ether treatment with titanium trichloride is carried out by bringing titanium trichloride into contact with an ether compound, and the treatment of titanium trichloride with an ether compound is carried out by bringing them into contact with each other in the presence of a diluent. Is advantageous. As such a diluent, it is preferable to use an inert hydrocarbon compound such as hexane, heptane, octane, decane, benzene and toluene. In addition, it is preferable that the process temperature in an ether process is 0-100 degreeC. Moreover, it does not restrict | limit especially about processing time, Usually, it is performed in the range of 20 minutes-5 hours.

The amount of the ether compound used is generally 0.05 to 3.0 mol, preferably 0.5 to 1.5 mol per 1 mol of titanium trichloride. If the amount of the ether compound used is less than 0.05 mol, the stereoregularity of the produced polymer cannot be sufficiently improved, which is not preferable. On the other hand, if the amount of the ether compound used exceeds 3.0 mol, the stereoregularity of the produced polymer is improved, but the yield is lowered, which is not preferable. Strictly speaking, titanium trichloride treated with an organoaluminum compound or an ether compound is a composition containing titanium trichloride as a main component.
In addition, as such a solid catalyst component (a), Solvay type titanium trichloride can be suitably used.

What is necessary is just to use the thing similar to the organoaluminum compound mentioned above as an organoaluminum compound (b).
Examples of the cyclic ester compound (c) include γ-lactone, δ-lactone, ε-lactone, etc., and it is preferable to use ε-lactone.
By mixing the above components (a) to (c), an olefin polymerization catalyst for producing the propylene-based multistage polymer used in the present embodiment can be obtained.
In addition, when a propylene-type resin is manufactured with the catalyst which consists of these components (a)-(c), it is known that a polypropylene-type resin with comparatively high isotacticity will be obtained.

In order to obtain the propylene-based multistage polymer used in this embodiment, it is preferable to polymerize propylene or copolymerize propylene and an α-olefin having 2 to 8 carbon atoms in the absence of hydrogen among the two-stage polymerization methods. .
Here, “in the absence of hydrogen” means substantially in the absence of hydrogen, and includes not only the case where no hydrogen is present, but also the case where a very small amount of hydrogen is present (for example, about 10 molppm). . In short, even if hydrogen is contained in such an extent that the intrinsic viscosity [η] of the first-stage propylene-based polymer or propylene-based copolymer measured in a 135 ° C. tetralin solvent does not fall below 10 dL / g, It is included in the meaning of “in the presence”.

By carrying out polymerization of propylene or copolymerization of propylene and α-olefin in the absence of such hydrogen, the components (P1) and (P2) of the ultrahigh molecular weight propylene-based polymer, that is, the propylene-based multistage polymer, are obtained. ) Can be manufactured.
In the absence of hydrogen, the component (P1) has a raw material monomer as a polymerization temperature, preferably 20 to 80 ° C., more preferably 40 to 70 ° C., and a polymerization pressure, generally at normal pressure to 1.47 MPa, preferably 0. It is preferably produced by slurry polymerization under the condition of 39 to 1.18 MPa.

The component (P2) of the propylene-based multistage polymer is preferably produced after the second stage.
The production conditions for the component (P2) are not particularly limited except that the olefin polymerization catalyst described above is used, but the raw material monomer is preferably 20 to 80 ° C., more preferably 60 to 70 ° C. as the polymerization temperature. In general, the polymerization pressure is preferably from normal pressure to 1.47 MPa, preferably from 0.19 to 1.18 MPa, and polymerized under the presence of hydrogen as a molecular weight regulator.

  In the above-described production method, preliminary polymerization may be performed before the main polymerization. When the prepolymerization is carried out, the powder morphology can be maintained well. In general, the prepolymerization is generally a polymerization temperature, preferably 0 to 80 ° C, more preferably 10 to 60 ° C, and a polymerization amount as a solid catalyst. Preferably, 0.001 to 100 g, more preferably 0.1 to 10 g of propylene is polymerized or copolymerized with propylene and an α-olefin having 2 to 8 carbon atoms per 1 g of the component.

Moreover, what blended the propylene homopolymer and the propylene-alpha-olefin copolymer can be used as a polypropylene resin used by this invention.
Examples of the propylene-α-olefin copolymer include a propylene-based block copolymer, which can be produced by the production method described in JP-A No. 2003-286060.
That is, in the presence of an olefin polymerization catalyst composed of the following components [A], [B] and [C], propylene is polymerized or ethylene and propylene are copolymerized to give a polypropylene component having an ethylene content of 0 to 5% by mass. Alternatively, the propylene / ethylene copolymer component is formed in an amount of 1 to 25% by mass of the total polymerization amount, and ethylene and propylene are copolymerized to form the propylene / ethylene copolymer component in an amount of 99 to 75% by mass of the total polymerization amount. The ethylene content is 10 to 80% by mass of the total polymerization amount.

[A] Solid catalyst component obtained by reacting the following compounds (a), (b), (c) or the following compounds (a), (b), (c), (d) (a) Magnesium compound (b) ) Titanium tetrachloride (c) Dialkyl phthalate (the alkyl group represents a straight or branched hydrocarbon group having 3 to 20 carbon atoms)
(D) Silicon tetrachloride [B] Organoaluminum compound [C] Organosilicon compound represented by the following general formula (II) (R ¹ ) (R ² CH ₂ ) Si (OR ³ ) (OR ⁴ ) (II) )
[Wherein, R ¹ is an alicyclic hydrocarbon group having 3 to 12 carbon atoms, R ² is a branched hydrocarbon group having 3 to 20 carbon atoms, and R ³ and R ⁴ are each independent, Represents a hydrocarbon group having 1 to 20 carbon atoms]

The solid catalyst component [A] is a catalyst component containing titanium, magnesium, halogen, and an electron donating compound, and specifically, the compound (a), (b), (c) or the compound (a). , (B), (c), (d).
Although there is no restriction | limiting in particular as a magnesium compound (a), What is represented by the following general formula (III) can be used preferably.
MgR ⁵ R ⁶ (III)
In the above general formula (III), R ⁵ and R ⁶ represent a hydrocarbon group, OR ⁷ (R ⁷ is a hydrocarbon group) or a halogen atom. Here, as the hydrocarbon group of R ⁵ , R ⁶ and R ⁷ , an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, and 7 to 20 carbon atoms. Examples of the aralkyl group of R ⁵ and R ⁶ include chlorine, bromine, iodine and fluorine. R ⁵ , R ⁶ and R ⁷ may be the same or different.

Specific examples of the magnesium compound (a) represented by the above general formula (III) include dimethylmagnesium, diethylmagnesium, diisopropylmagnesium, dibutylmagnesium, dihexylmagnesium, dioctylmagnesium, ethylbutylmagnesium, diphenylmagnesium, dicyclohexylmagnesium. Alkyl magnesium and aryl magnesium such as butyl octyl magnesium; alkoxy magnesium such as dimethoxy magnesium, diethoxy magnesium, dipropoxy magnesium, dibutoxy magnesium, dihexyloxy magnesium, dioctoxy magnesium, diphenoxy magnesium, and dicyclohexyloxy magnesium; Allyloxymagnesium; ethylmagnesium chloride, butyl magne Alkyl magnesium halides such as um chloride, hexyl magnesium chloride, isopropyl magnesium chloride, isobutyl magnesium chloride, t-butyl magnesium chloride, phenyl magnesium bromide, benzyl magnesium chloride, ethyl magnesium bromide, butyl magnesium bromide, phenyl magnesium chloride, butyl magnesium iodide, Arylmagnesium halides; butoxymagnesium chloride, cyclohexyloxymagnesium chloride, phenoxymagnesium chloride, ethoxymagnesium bromide, butoxymagnesium bromide, ethoxymagnesium iodide and other alkoxymagnesium halides and allyloxymagnesium halides; magnesium chloride, magnesium bromide Examples thereof include magnesium halides such as nesium and magnesium iodide.
Among these magnesium compounds (a), magnesium halide, alkoxymagnesium, and alkylmagnesium halide can be preferably used. Of these, alkoxymagnesium is particularly preferable.
The magnesium compound (a) can be prepared from metallic magnesium or a compound containing magnesium.

The alkyl group of the dialkyl phthalate (c) is a linear hydrocarbon group or branched hydrocarbon group having 3 to 20 carbon atoms, specifically, an n-propyl group, an isopropyl group, an n-butyl group, Isobutyl group, t-butyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1,1-dimethylpropyl group, 1-methylpentyl group, 2-methylpentyl group, 3- Methylpentyl group, 4-methylpentyl group, 1-ethylbutyl group, 2-ethylbutyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group, 2-methylhexyl group, 3 -Methylhexyl group, 4-methylhexyl group, 2-ethylhexyl group, 3-ethylhexyl group, 4-ethylhexyl group, 2-methylpentyl group, 3-methylpentene Group, 2-ethylpentyl, 3-ethylpentyl group, and the like. Among these alkyl groups, a linear or branched aliphatic hydrocarbon group having 4 or more carbon atoms is preferable.
Specific examples thereof include di-n-butyl phthalate, diisobutyl phthalate, di-n-heptyl phthalate and the like. Of these, di-n-butyl phthalate and diisobutyl phthalate are particularly preferable. In addition, these compounds may be used alone or in combination of two or more.

  To the solid catalyst component [A], silicon tetrachloride (d) can be further added to the compounds (a), (b) and (c). Silicon tetrachloride (d) is used in such a ratio that the molar ratio to the magnesium compound (a) is usually 0.01 or more, preferably 0.10 or more. If this molar ratio is less than 0.01, the catalyst activity and stereoregularity may not be sufficiently improved, or the amount of fine powder in the produced polymer may increase.

  There is no restriction | limiting in particular as a method of making said each compound contact, What is necessary is just to make it contact by a well-known method. Examples thereof include methods described in JP-A-53-43094, JP-A-55-135102, JP-A-55-135103, JP-A-56-18606, and the like. Specifically, (1) a magnesium compound (a) or a complex compound of a magnesium compound (a) and a dialkyl phthalate (c), a dialkyl phthalate (c) and a grinding aid used as desired A method of pulverizing in the presence and reacting with titanium tetrachloride (b), (2) a liquid compound of magnesium compound (a) having no reducing ability and titanium tetrachloride (b), dialkyl phthalate (c) (3) a method in which titanium tetrachloride (b) is reacted with the product obtained in (1) or (2) above, (4) A method in which a dialkyl phthalate (c) and titanium tetrachloride (b) are further reacted with the product obtained in (1) or (2) above; (5) a magnesium compound (a) or a magnesium compound (a); Phthalic acid dial The complex compound with ru (c) is pulverized in the presence of a dialkyl phthalate (c), titanium tetrachloride (b), and a pulverization aid used as desired, and then silicon tetrachloride ( The method etc. which are processed by d) are mentioned.

In addition to these methods, JP-A-56-166205, JP-A-57-63309, JP-A-57-190004, JP-A-57-300407, JP-A-58- The solid catalyst component [A] can also be prepared by the method described in JP 47003A.
The amount of titanium tetrachloride (b) used is usually in the range of 0.5 to 100 mol, preferably 1 to 50 mol, per 1 mol of magnesium in the magnesium compound (a). The amount of dialkyl phthalate (c) used is usually 0.01 to 10 mol, preferably 0.05 to 0.15 mol, per 1 mol of magnesium in the magnesium compound (a). . Furthermore, when adding silicon tetrachloride (d), it is good to make the usage-amount into said ratio.

In the preparation of the solid catalyst component [A], the contact temperature of the compounds (a) to (d) is usually in the range of −20 to 200 ° C., preferably 20 to 150 ° C., and the contact time is usually 1 Minutes to 24 hours, preferably 10 minutes to 6 hours.
At this time, the contact procedure of the compounds (a) to (d) is not particularly limited. For example, each compound may be contacted in the presence of an inert solvent such as a hydrocarbon, or each compound may be previously contacted after being diluted with an inert solvent such as a hydrocarbon. Examples of the inert solvent include aliphatic hydrocarbons such as n-pentane, isopentane, n-hexane, n-heptane, n-octane and isooctane; aromatic hydrocarbons such as benzene, toluene and xylene, or a mixture thereof. Can be mentioned.
Further, in the preparation of the solid catalyst component [A], the titanium tetrachloride (b) is contacted twice or more, and is sufficiently supported on the magnesium compound (a) serving as a catalyst carrier.
The solid catalyst component [A] obtained by the above contact may be washed with an inert solvent such as hydrocarbon. Examples of the inert solvent include the same ones as described above. Further, the solid catalyst component [A] can be stored in a dry state, or can be stored in an inert solvent such as a hydrocarbon.

  As the organoaluminum compound [B], those containing an alkyl group, a halogen atom, a hydrogen atom or an alkoxy group, an aluminoxane and a mixture thereof can be preferably used. Specifically, trialkylaluminum such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum; dialkyl such as diethylaluminum monochloride, diisopropylaluminum monochloride, diisobutylaluminum monochloride, dioctylaluminum monochloride Examples include aluminum monochloride; alkylaluminum sesquihalides such as ethylaluminum sesquichloride; chain aluminoxanes such as methylaluminoxane. Among these organoaluminum compounds [B], trialkylaluminum having a lower alkyl group having 1 to 5 carbon atoms, particularly trimethylaluminum, triethylaluminum, tripropylaluminum and triisobutylaluminum are preferable. These organoaluminum compounds [B] may be used alone or in combination of two or more.

The organosilicon compound [C] is represented by the general formula (II).
Specific examples of R ¹ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a 1-norbornyl group, a 2-norbornyl group, and the like. A cyclohexyl group is preferred. Examples of R ² include isopropyl group, isobutyl group, sec-butyl group, t-butyl group, neopentyl group and the like, and isopropyl group is particularly preferable. R ³ and R ⁴ are alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, hexyl group, octyl group and cyclohexyl group, alkenyl groups such as allyl group, propenyl group and butenyl group. Group, aryl group such as phenyl group, tolyl group and xylyl group, aralkyl group such as phenethyl group and 3-phenylpropyl group. Among these, an alkyl group having 1 to 10 carbon atoms is particularly preferable.

Specific examples of the organosilicon compound [C] include cyclopropylisobutyldimethoxysilane, cyclopropylisopentyldimethoxysilane, cyclopropyl-2-methylbutyldimethoxysilane, cyclopropylneopentyldimethoxysilane, and cyclopropyl-2-methyl. Xyldimethoxysilane, cyclobutylisobutyldimethoxysilane, cyclobutylisopentyldimethoxysilane, cyclobutyl-2-methylbutyldimethoxysilane, cyclobutylneopentyldimethoxysilane, cyclobutyl-2-methylhexyldimethoxysilane, cyclopentylisobutyldimethoxysilane, cyclopentyliso Pentyldimethoxysilane, cyclopentyl-2-methylbutyldimethoxysilane, cyclopentylneopentyldimethoxy Silane, cyclopentyl-2-methylhexyldimethoxysilane, cyclohexylisobutyldimethoxysilane, cyclohexylisopentyldimethoxysilane, cyclohexyl-2-methylbutyldimethoxysilane, cyclohexylneopentyldimethoxysilane, cyclohexyl-2-methylhexyldimethoxysilane, cyclohex Butyl isobutyldimethoxysilane, cycloheptylisopentyldimethoxysilane, cycloheptyl-2-methylbutyldimethoxysilane, cycloheptylneopentyldimethoxysilane, cycloheptyl-2-methylhexyldimethoxysilane, cyclooctylisobutyldimethoxysilane, Cyclooctylisopentyldimethoxysilane, cyclooctyl-2-methylbutyldimethoxysilane, cycl Octylneopentyldimethoxysilane, cyclooctyl-2-methylhexyldimethoxysilane, 1-norbornylisobutyldimethoxysilane, 1-norbornylisopentyldimethoxysilane, 1-norbornyl-2-methylbutyldimethoxysilane, 1-nor Bornyl neopentyldimethoxysilane, 1-norbornyl-2-methylhexyldimethoxysilane, 2-norbornylisobutyldimethoxysilane, 2-norbornylisopentyldimethoxysilane, 2-norbornyl-2-methylbutyldimethoxysilane, 2 -Norbornyl neopentyl dimethoxysilane, 2-norbornyl-2-methylhexyl dimethoxysilane and the like. Of these, cyclopentylisobutyldimethoxysilane and cyclohexylisobutyldimethoxysilane are preferred.
These organosilicon compounds [C] may be used alone or in combination of two or more.

Although there is no restriction | limiting in particular about the usage-amount of said component [A]-[C], Solid catalyst component [A] is 0.0005-1 mmol normally per liter of reaction volume converted into a titanium atom. An amount that is in the range is used.
The organoaluminum compound [B] is used in such an amount that aluminum / titanium (atomic ratio) is usually in the range of 1 to 1,000, preferably 10 to 500.
When this atomic ratio deviates from the above range, the catalytic activity may be insufficient.
The organosilicon compound [C] is such that the organosilicon compound [C] / organometallic compound [B] (molar ratio) is usually in the range of 0.02 to 2.0, preferably 0.05 to 1.0. The correct amount is used. If this molar ratio deviates from the above range, sufficient catalytic activity may not be obtained.

  The propylene-based block copolymer used in the present application is preferably prepared by polymerizing propylene or copolymerizing ethylene and propylene in the first stage using the above-mentioned olefin polymerization catalyst, and the ethylene content is 0 to 5% by mass. Polypropylene component or propylene / ethylene copolymer component, preferably a polypropylene component having an ethylene content of 0% by mass, that is, a propylene homopolymer part is 1 to 25% by mass, preferably 5 to 20% by mass of the total polymerization amount. Then, in the second stage, ethylene and propylene are copolymerized, and the propylene / ethylene copolymer component, that is, the copolymerized portion is 99 to 75% by mass of the total polymerization amount, preferably 95 to 80%. A block copolymer having a mass% of ethylene and an ethylene content of 10 to 80% by mass, preferably 15 to 45% by mass, of the total polymerization amount is produced.

Furthermore, prepolymerization of olefins, preferably α-olefins, can be performed before forming the polypropylene component or propylene / ethylene copolymer component.
In the preliminary polymerization, the catalyst to be used is not particularly limited, but preferably, the above-described olefin polymerization catalyst is used. In this case, as an electron donating component, in addition to the organic compound [C], dicyclopentyldimethoxysilane, cyclopentylethyldimethoxysilane, cyclopentylisopropyldimethoxysilane, cyclopentyltertiarybutyldimethoxysilane, texylcyclopentyldimethoxysilane, texyl Cyclohexyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, ditertiarybutyldimethoxysilane, and the like can be used. Of these, dicyclopentyldimethoxysilane is preferred.
The α-olefin is not particularly limited, and specifically, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 3-methyl-1 -Pentene, 4-methyl-1-pentene, vinylcyclohexane and the like. Of these, ethylene and propylene are preferred. These α-olefins may be used alone or in combination of two or more.

In the prepolymerization, the α-olefin in the presence of the above components [A], [B] and [C] or other organosilicon compounds is usually used at a temperature in the range of 1 to 100 ° C. and normal pressure to 5 MPa (Gauge). The polymerization may be performed at a pressure of The polymerization time is 1 minute to 10 hours, preferably 10 minutes to 5 hours. The prepolymerization amount is usually 0.1 to 1,000% by mass, preferably 1.0 to 500% by mass, based on the solid catalyst component [A].
Furthermore, the olefin polymer obtained by prepolymerization can be used as a prepolymerization catalyst component. That is, the prepolymerization catalyst component can be used as an olefin polymerization catalyst component to produce a propylene-based block copolymer used in the present invention.

The method for producing a propylene-based block copolymer is not particularly limited with respect to the polymerization type, and can be applied to any of solution polymerization, slurry polymerization, gas phase polymerization, bulk polymerization, and the like. In addition, the polymerization method may be either batch polymerization or continuous polymerization. For example, in the case of producing in a continuous mode, the raw material propylene gas, the molecular weight regulator hydrogen gas and the catalyst are supplied to the former stage polymerization tank, and the propylene homopolymerization part is produced by controlling the polymerization amount by the polymerization time, and then the latter stage. Then, the block is obtained by adding the ethylene propylene gas, ethylene gas, hydrogen gas, and a catalyst as necessary to produce a copolymer part.
In the production of the copolymerization part, ethylene may be used alone, but if necessary, the α-olefin other than ethylene and propylene may be combined.
The conditions for propylene homopolymerization are not particularly limited as long as the above-mentioned polymerization amount can be obtained during polymerization, but the polymerization pressure is usually from atmospheric pressure to 8 MPa (Gauge), preferably from 0.2 to 5 MPa ( Gauge) and the polymerization temperature are usually selected appropriately in the range of 0 to 200 ° C, preferably 30 to 100 ° C. The polymerization time is usually about 5 minutes to 20 hours, preferably about 10 minutes to 10 hours.

  The conditions for copolymerization of ethylene and propylene are not particularly limited as long as the above-described ethylene content and polymerization amount can be obtained at the time of copolymerization, but the polymerization pressure is usually from atmospheric pressure to 8 MPa (Gauge), Preferably it is 0.2-5 Mpa (Gauge), and a polymerization temperature is 0-200 degreeC normally, Preferably it is suitably selected in the range of 20-100 degreeC. The polymerization time is usually about 1 minute to 20 hours, preferably about 1 minute to 10 hours. The ratio of ethylene to propylene to be supplied is 0.01 to 9, preferably 0.05 to 2.3 in terms of a molar ratio of ethylene / propylene.

In this invention, the polypropylene-based extruded foam is formed by extrusion foaming. In particular, a known extrusion foaming apparatus that is generally used can be used.
Specifically, the polypropylene-based resin and various additives described above are charged into an extrusion foaming apparatus, melt-kneaded, extruded into a low-pressure region and foamed to obtain a polypropylene-based extruded foam, but when extruded into a low-pressure region, The conditions are such that the apparent shear rate of the die wall surface in the region where the die clearance is minimum near the die exit is 10 s ^-1 or more and 1000 s ^-1 or less.
When the apparent shear rate is less than 10 s ⁻¹ , the productivity is poor, and when it exceeds 1000 s ⁻¹ , the surface characteristics of the extruded foam may be deteriorated. A more preferable range of the apparent shear rate is 30 ^-1 or more and 500 s ^-1 or less, and a further preferable range is 30 ^-1 or more and 300 s ^-1 or less.

As a means for foaming the polypropylene resin, a foam material is contained. Specifically, physical foaming in which a foaming gas as a foaming material is injected into a molten resin raw material, chemical foaming in which a foaming agent as a foaming material is mixed into the resin raw material, or the like can be employed.
Examples of the fluid to be injected by physical foaming include inert gases such as carbon dioxide and nitrogen.

As foaming agents used for chemical foaming, inorganic chemical foaming agents such as sodium bicarbonate and ammonium carbonate, and organic chemical foaming such as azodicarbonamide, azobisisobutyronitrile, N, N-dinitrosopentatetramine, etc. Agents. Of these, inorganic chemical foaming agents are preferred. For these inorganic chemical foaming agents, for example, foaming aids such as organic acids such as citric acid, talc, lithium carbonate, etc. are used as necessary to stably and uniformly make the foam of the extruded foam. A nucleating agent such as inorganic fine particles may be added.
In addition, when using an inorganic chemical foaming agent, a masterbatch of a polyolefin resin having a concentration of 10% by mass or more and 50% by mass or less is usually from the viewpoint of handleability, storage stability, and dispersibility in polypropylene resin. It is preferable to be used as What is necessary is just to select the addition amount of these inorganic type chemical foaming agents suitably by a kind and the density | concentration in a masterbatch. In general, it is preferably contained in the range of 0.1 to 40 parts by mass, more preferably in the range of 0.5 to 30 parts by mass with respect to 100 parts by mass of the polypropylene resin of the present invention. Can be selected.

These foam materials may be used alone or in combination of two or more.
The amount of the foam material used may be added to 1 g of polypropylene resin so that the amount of gas generated to generate bubbles is 7.0 × 10 ⁻⁵ mol or more and 1.5 × 10 ⁻³ mol or less. preferable. More preferably, it is 1.0 × 10 ⁻⁴ mol or more and 1.0 × 10 ⁻³ mol or less.
Specifically, when the above gas generation amount is applied in physical foaming using carbon dioxide, carbon dioxide is added to the resin raw material in an amount of 0.31% by mass to 6.2% by mass, more preferably 0.44% by mass to 4%. This is equivalent to dissolving 2% by mass or less.
Also in chemical foaming, it is preferable to adjust the addition amount of various chemical foaming agents so that the amount of gas generated in the extrusion process is the same as the range of the number of moles.

And when performing extrusion foaming, additives, such as antioxidant, a neutralizing agent, a flame retardant, can be used as needed. The blending amount of the additive is not particularly limited and can be adjusted as appropriate.
Further, silica, activated carbon, zeolite, silica gel, or fibrous activated carbon may be blended as the powdery or fibrous porous filler.
In addition, as a crystallization nucleating agent, talc, an organic carboxylate, an organic phosphate, or a sorbitol-based nucleating agent may be blended.

The polypropylene-based extruded foam thus obtained is excellent in heat insulation performance because the expansion ratio is 3 times or more.
Further, even when the apparent shear rate is low, a high-foamed body having a foaming ratio of 3 times or more can be produced, so that the clearance at the die exit can be widened. Therefore, a thick extruded foam can be formed and the surface appearance is good.
Furthermore, the polypropylene resin used in the present invention is excellent in recycling performance, and also has good chemical resistance and heat resistance. Therefore, a polypropylene-based extruded foam produced by molding a polypropylene resin as a material. The molded body is also excellent in recycling performance, chemical resistance and heat resistance. In addition, since the polypropylene resin is low in cost, the material cost can be reduced.
As described above, a polypropylene-based extruded foam molded body that is thick and has excellent recycling performance, chemical resistance, and heat resistance is highly useful as an interior / exterior material in the housing and automobile fields.
And since a well-known extrusion foaming apparatus can be used as it is, it is not necessary to invest in new equipment. Therefore, since there is no significant change in the manufacturing process, it can be easily implemented.

  In the polypropylene-based extruded foam of the present invention, the expansion ratio is preferably 3 to 10 times.

In the present invention, a polypropylene-based extruded foam having a foaming ratio of 3 times or more can be formed because it is used as the above-described polypropylene-based resin material. On the other hand, if the expansion ratio exceeds 10 times, formation at a low shear rate becomes difficult, and the surface appearance may be roughened.
Therefore, an extruded foam having an expansion ratio of 3 to 10 times is a high foam and a good surface appearance, and a polypropylene-based extruded foam having a good surface appearance by molding in the latter stage. can get.

  In the polypropylene-based extruded foam of the present invention, the die preferably has a slit-shaped or cylindrical flow path at the outlet.

The shape of the polypropylene-based extruded foam is determined by the shape of the die outlet formed in the die. The shape of the die outlet can be any shape such as a circle, a rhombus, a slit, or a cylinder, but among these, the adjustment of the thickness is easy, and from the point that the moldability is excellent, the slit or A cylindrical shape is preferred.
In addition, as a molding method of a foam, it is also possible to use a so-called strip-shaped converging body in which foams extruded from a plurality of die outlets are converged to form one foam. In this case, the shapes of the plurality of die outlets may all be the same, or a plurality of various shapes may be formed on one die.

  In the polypropylene-based extruded foam of the present invention, the minimum value of the die clearance at the portion where the die clearance is minimum in the vicinity of the die exit is preferably 1 mm or more.

In the conventional extrusion foam molding, when extruding from the extrusion foaming apparatus, it is necessary to rapidly reduce the pressure, and thus it is necessary to narrow the die clearance. That is, it was difficult to form a thick extruded foam.
According to this invention, since the minimum value of the die clearance is 1 mm or more, a thick extruded foam can be formed.

  In the polypropylene-based extruded foam of the present invention, the set temperature of the die is preferably 170 ° C. or higher and 210 ° C. or lower.

If the set temperature of the die is less than 170 ° C, extrusion may be difficult, and if it exceeds 210 ° C, the foaming performance of the resin raw material may be deteriorated.
Therefore, by setting the die set temperature at 170 ° C. or higher and 210 ° C. or lower, a polypropylene-based extruded foam having excellent moldability and a high expansion ratio can be obtained.

  The polypropylene-based extruded foam of the present invention is preferably extruded to have a thickness of 2 mm to 30 mm.

Conventionally, it has been difficult for polypropylene-based extruded foam to be highly foamed at a low shear rate. Therefore, it is necessary to reduce the clearance of the die, and the thickness is small.
According to this invention, the polypropylene-based extruded foam has a thickness of 2 mm or more and 30 mm or less. In addition, when extrusion foaming is performed with a die having a circular die outlet, a thick extruded foam having a diameter of 2 mm to 30 mm can be obtained.
Therefore, since the polypropylene-based extruded foam is thick or thick, it is useful to mold this extruded foam with a mold and use it as an interior / exterior material in the housing and automobile fields, as well as food trays, etc. It can be easily applied to other uses.
As described above, according to the present invention, it is possible to easily extrude a thick extruded foam having a good surface appearance. Therefore, by sandwiching the extruded foam plasticized in this heated state with a mold, it is complicated. An extruded foam molded body having a shape can be easily formed. In addition, by filling the mold with a skin material such as a nonwoven fabric or fabric in advance, it is possible to easily obtain a molded product with a decorated surface. At this time, an adhesive layer may be provided between the skin materials of the extrusion foamed molded article using coextrusion or the like. As the adhesive layer, unfoamed polypropylene can be used.
Further, if the extruded foam molded body has a multilayer structure by coextrusion with a non-foamed layer, a molded body having a multilayer structure including a foamed layer and a non-foamed layer can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, as a manufacturing apparatus for producing a polypropylene-based extruded foam molded article, an extrusion foaming apparatus and a mold molding apparatus that molds an extruded foam obtained by extrusion foaming with the extrusion foaming apparatus using a mold are provided. Use things. In addition, you may provide the conveying apparatus which conveys the extrusion foaming foamed with the extrusion foaming apparatus to a metal-molding apparatus as a manufacturing apparatus. Various configurations such as a roller conveyor can be used for the transport device. In addition, it is preferable to employ | adopt the structure for which a conveying apparatus does not cool an extrusion foam in the case of conveyance of an extrusion foam.
The mold forming apparatus forms an extruded foam into a desired shape by pressurization or suction using a mold, and various configurations can be used.

[Configuration of extrusion foaming equipment]
As the extrusion foaming apparatus used in the present invention, a known extrusion foaming apparatus capable of heating the resin raw material in a molten state, kneading while applying an appropriate shear stress, and performing extrusion foaming can be used. Further, as the extruder constituting the extrusion foaming apparatus, either a single screw extruder or a twin screw extruder can be used. Specifically, for example, a tandem extrusion foam molding apparatus connected to two extruders disclosed in JP-A-2004-237729 is exemplified.
In this embodiment, an extrusion foaming apparatus that performs extrusion foaming by physical foaming is used.
FIG. 1 is a schematic view schematically showing an extrusion foaming apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the extrusion foaming apparatus 100 includes a hopper 110 into which a resin raw material is charged, a cylinder 120 as an extruder for melting and kneading the resin raw material, and a gas introduction path 130 for introducing a blowing agent gas into the cylinder 120. And a gear pump 140 for extruding the resin raw material, a die 150 for forming an extruded foam, and a mold forming apparatus 160 for forming a mold.

The hopper 110 also functions as a measuring device, and can also measure at the same time as the resin raw material is charged.
The cylinder 120 is formed in a substantially cylindrical shape, and has a substantially columnar screw 121 having a diameter smaller than the inner diameter of the cylinder 120. The screw 121 has a spiral wing 122 on its outer peripheral surface, and is supported so as to be rotatable about the axis of the screw 121. As the screw 121 rotates inside the cylinder 120, the resin material in the cylinder 120 is melted and kneaded.
The extrusion temperature in the cylinder 120 may be set as appropriate, but for example, it is preferably set to 170 ° C. or higher and 230 ° C. or lower. If the extrusion temperature is less than 170 ° C, extrusion may be difficult, and if it exceeds 230 ° C, foaming performance may be reduced.

The gas introduction path 130 is a flow path connected to the inside of the cylinder 120 and introduces foaming gas. Examples of the foaming gas include inert gases such as carbon dioxide and nitrogen gas. By introducing the foaming gas, the resin raw material and the foaming gas are mixed in the cylinder 120.
The gear pump 140 adjusts the flow rate of the mixture of the resin raw material melted and kneaded in the cylinder 120 and the foaming gas, and stably pushes it out to the die 150.

The die 150 is formed by extruding a resin raw material into a desired shape. In this embodiment, the die shown in FIG. 2 was used.
2A and 2B are schematic views showing the shape of the die according to the present embodiment, in which FIG. 2A is a sectional view of the die, and FIG. 2B is a side view on the die outlet side.
As shown in FIGS. 2A and 2B, the die 150 has a cylindrical flow channel 151 having an annular cross section. The diameter of the ring on the die exit side of the flow channel 151 is preferably 4 mm or more and 1000 mm or less. When the diameter is less than 4 mm, they are integrated when extruded and foamed, and may not be formed into a cylindrical shape. If the diameter exceeds 1000 mm, stable continuous extrusion becomes difficult.

  In addition, the flow path 151 is formed in series inside the die 150 with the radius of the ring of the die outlet 151 </ b> A being larger than the radius of the ring of the die entrance. Further, the closer the channel 151 is to the die outlet 151A, the smaller the clearance becomes. Assuming that the site where the clearance is minimized is the minimum site S, the clearance at the minimum site S may be set as appropriate, but is preferably 1 mm or more. When the thickness is less than 1 mm, the surface appearance is deteriorated and it is difficult to obtain a foam having a sufficient thickness. A more preferable range of the clearance is 1 mm or more and 5 mm or less.

Here, the shear rate will be described.
The shear rate is an apparent shear rate on the channel wall surface, where Q is the volume flow rate, H is the clearance at the minimum site S of the cylindrical die 150, and r is the radius of the ring at the minimum site S. Is defined as:
γ = 6 × Q / πrH ²

Shear rate at the minimum region S of the die 150 is preferably 10s ^-1 or 1000 s ^-1 or less, more preferably 30s ^-1 or 500 s ^-1 or less. When the shear rate is less than 10 s ⁻¹ , the productivity is poor, and when it exceeds 1000 s ⁻¹ , the surface properties of the extruded foam deteriorate.
The temperature of the die 150 is preferably set to 170 ° C. or higher and 210 ° C. or lower. If the temperature of the die 150 is less than 170 ° C, extrusion may be difficult, and if it exceeds 210 ° C, the foaming performance of the resin raw material may be deteriorated.
The shear rate is preferably adjusted by selecting the resin flow rate and the cross-sectional area of the minimum portion of the die clearance.

  The mold forming apparatus 160 includes molds 161 and 162. In the present embodiment, the mold molding apparatus 160 exemplifies a shape for molding a polypropylene-based extruded foam molded body having a U-shaped cross section, for example, but is not limited thereto.

[Operation of manufacturing equipment]
Next, the operation of the manufacturing apparatus will be described.
First, the operation | movement at the time of implementing extrusion foaming with the extrusion foaming apparatus 100 is demonstrated.
The aforementioned polypropylene resin is put into the hopper 110.
The resin charged into the hopper 110 is supplied to the cylinder 120.
Inside the cylinder 120, the screw 121 rotates about the axis, so that the resin is melted and kneaded by the screw 121. At this time, since carbon dioxide is introduced as a foaming fluid from the gas introduction path 130, the resin and carbon dioxide are mixed.
The melt-kneaded resin and carbon dioxide mixture is pushed out of the cylinder 120 and introduced into the gear pump 140. The flow rate of the resin is adjusted by the gear pump 140 and pushed out to the die 150.

In the die 150, an extruded foam is formed by extruding a resin along the internal shape. The flow rate is adjusted so that the shear rate at the minimum clearance S near the outlet of the die 150 is in the range of 10 s ^{−1 to} 1000 s ⁻¹ . In the present embodiment, the adjustment is made to be, for example, 100 s ⁻¹ .
Then, the resin is extruded from the die 150 and foamed at the same time to form a foam, and a cylindrical extruded foam is obtained.

The extruded foam that has been extruded and foamed by the extrusion foaming apparatus 100 is immediately molded by the molds 161 and 162 of the mold molding apparatus 160. That is, when the extruded foam reaches a predetermined length as shown in FIG. 3A, the molds 161 and 162 are closed and the extruded foam is sandwiched as shown in FIG. The body is filled into a mold cavity configured with the molds 161 and 162 closed, and then molded. Then, the molds 161 and 162 are held closed, and the extruded foam is cooled and solidified in the molds 161 and 162. The mold temperature at this time is set to about 40 ° C., for example, and is cooled and solidified for about 30 seconds. Thereafter, as shown in FIG. 3C, the molds 161 and 162 are opened, and the extruded foam molded body 190 (see FIGS. 7 and 8) is taken out.
The time until this extruded foam is molded is the time from when it is extruded until it is cooled by the molds 161 and 162 and solidified. That is, when being molded by being supplied to the mold molding apparatus 160, at least the inside of the extruded foam is not cooled to the crystallization temperature, and the extruded foam almost eliminates cells depending on the mold shape during molding. What is necessary is just a state which can be deformed so that it may follow a metallic mold shape, without destroying. Specifically, when an extruded foam having a thickness of about 6 mm is molded into a flat plate having a thickness of 5 mm at room temperature, the mold can be molded with almost no expansion ratio within 60 seconds after being extruded and foamed. . That is, the expansion ratio of the obtained extrusion foamed molded article is 3 times or more, preferably 3 to 10 times.
In addition, although mold temperature should just be temperature below melting | fusing point of a resin raw material, Preferably it is 5 to 80 degreeC. The cooling time is usually 5 seconds or more and 5 minutes or less, preferably 10 seconds or more and 2 minutes or less. The molds 161 and 162 are preferably clamped quickly after the extruded foam is introduced into the mold molding apparatus 160. In addition, the shapes of the molds 161 and 162 are appropriately selected so as to obtain the desired shape of the extruded foam 190. It is preferable in terms of productivity to use a normal split mold.

[Effects of Embodiment]
As described above, in the present embodiment, the following operational effects can be achieved.
In the present embodiment, extrusion foaming is performed by using a known extrusion foaming apparatus 100 using the above-described polypropylene-based resin, with an apparent shear rate at a portion where the clearance near the exit of the die 150 is minimum being 10 s ^-1 or more and 1000 s ^-1 or less. . Thereby, a polypropylene-based extruded foam having an expansion ratio of 3 times or more is obtained.

In addition, since the polypropylene-based extruded foam 190 obtained after the mold forming in the latter stage is a high foam having a foaming ratio of 3 times or more, it has better heat insulation, its surface appearance is good, and the housing field In addition, it is highly useful as an interior / exterior material in the automobile field, as a tray for foods, etc., and can be easily applied to parts to other fields, thereby improving versatility.
Since this polypropylene-based extruded foam 190 uses a polypropylene-based resin as a material, it is excellent in heat resistance, chemical resistance and recycling performance. Further, since the polypropylene resin is low in cost, the cost of the material can be reduced.

Furthermore, extrusion foaming can produce a high foam having a foaming ratio of 3 times or more even when the apparent shear rate at the minimum portion S of the die clearance is a low shear rate of 10 s ^-1 or more and 1000 s ^-1 or less. it can. Therefore, since it is not necessary to increase the shear rate, the die clearance can be widely formed, and as a result, a thick extruded foam can be formed. For this reason, it is possible to produce a polypropylene-based extruded foamed molded body 190 having a desired shape by die molding in a state where at least the inside is not crystallized.

  In this embodiment, an extruded foam having a foaming ratio of 3 times or more can be produced with the known extrusion foaming apparatus 100. That is, it can be manufactured by a method similar to the conventional method. Therefore, there is no need for new capital investment, and since there is no significant change in the manufacturing method, there is no time and effort, and a sufficiently thick extruded foam that can be molded at a later stage can be easily manufactured. .

  In addition, since extrusion foaming is performed at a low shear rate, the occurrence of melt fracture and corrugated marks on the surface of the foam can be suppressed, and a foam having a good surface appearance can be provided.

  Conventionally, it was difficult to foam a polypropylene resin with nitrogen gas, but by setting an appropriate condition range using the above-mentioned polypropylene resin, it was possible to foam with nitrogen gas. .

[Modification of Embodiment]
In the above embodiment, a cylindrical die is used. However, the shape of the die can be a shape according to the purpose, and is not limited thereto.
For example, as shown in FIG. 4, a die 170 having a parallel tubular flow path having a slit-like cross section may be used. In this case, when the thickness of the slit at the portion T where the clearance near the die outlet 171 is minimum is H, the width of the slit at the die outlet 171 is W, and the volume flow rate is Q, the shear rate γ is defined as follows. .
γ = 6 × Q / (WH ² )

Further, as shown in FIG. 5, a die 180 having a circular channel having a circular cross section may be used. In this case, when the radius of the flow path of the portion U where the clearance near the die outlet 181 is minimum is r and the volume flow rate is Q, the shear rate γ is defined as follows.
γ = 4 × Q / (πr ³ )

  Furthermore, the die may have a conical flow path having a circular cross section, or a parallel tubular flow path having an arbitrary cross section. Thus, a die having a shape according to the purpose can be used.

In the above embodiment, a die having only one cylindrical outlet is used. However, by using a die having a plurality of outlets, a plurality of extruded foams are converged to form a single one. It is also possible to form a so-called strip-shaped bundle of two foams.
In this case, all of the plurality of outlet shapes may be the same shape, or each outlet may have a different shape, for example, a circular shape, a diamond shape, a slit shape, or the like. Moreover, even if it is the same circular shape, it can also be set as several types of circular shapes by changing the magnitude | size of each diameter.

  Moreover, in the said embodiment, although extrusion foaming was performed by physical foaming, it may be based on chemical foaming. In this case, it can be carried out by adding the aforementioned foaming agent or the like together with the resin raw material or by dry blending.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the content of an Example etc. at all.
<About resin>
In this example, the following four types of polypropylene resin compositions are used.

Resin A: Linear polypropylene Resin B: 70% by mass of resin A + 30% by mass of flexible polypropylene resin Resin C: Branched polypropylene (trade name “PF814”, manufactured by Basell)
Resin D: Linear polypropylene (trade name “VP103W”, manufactured by Prime Polymer Co., Ltd.)

[Production Method of Resin A (Propylene Multistage Polymer)]
(1) Preparation of prepolymerization catalyst component:
A 5-liter 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 g of diethylaluminum chloride were added, and a commercially available Solvay type titanium trichloride catalyst (Tosoh Corporation) was added. -20 g of Finechem Co., Ltd. was added. While maintaining this at 20 ° C. with stirring, propylene was continuously introduced. After 80 minutes, stirring was stopped to obtain a prepolymerized catalyst component in which 0.8 g of propylene was polymerized per 1 g of titanium trichloride catalyst.

(2) 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, propylene was introduced with stirring, and the system was stabilized at an internal temperature of 50 ° C. and a total pressure of 0.78 MPa. Then, 200 ml of heptane slurry containing 0.75 g of the prepolymerized catalyst component in terms of solid catalyst was added. The polymerization was started. Propylene was continuously supplied for 1.0 hour for polymerization to obtain a polymer (P1 component). As a result of sampling and analyzing a part thereof, the intrinsic viscosity was 15.4 dL / g. Thereafter, the internal temperature was lowered to 40 ° C. or lower, stirring was weakened, and depressurization was performed.
Again, the internal temperature was 65 ° C., 0.10 MPa of hydrogen was added, and propylene was introduced while stirring. While continuously supplying propylene at a total pressure of 0.78 MPa, polymerization was carried out at 65 ° C. for 4 hours to obtain a polymer (P2 component). At this time, as a result of sampling and analyzing a part of the polymer, the intrinsic viscosity was 3.31 dL / g.
After completion of the polymerization, 50 ml of methanol was added, and the temperature was lowered and the pressure was released. The entire contents were transferred to a filtration tank equipped 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 6 liters of heptane at 85 ° C. and vacuum-dried to obtain 3.3 kg of a propylene polymer.
As a result, the mass ratio of the polymer components of the polymer (P1) and the polymer (P2) is 15.3: 84.7, and the intrinsic viscosity of the polymer produced in the second stage is 1.13 dL / g.

[Method for producing flexible polypropylene resin (propylene-ethylene copolymer)]
(1) Preparation of magnesium compound After fully replacing the stainless steel catalyst reaction tank with nitrogen gas, 25 kg of ethanol, 1.6 kg of iodine and 16 kg of magnesium metal were added to the system under reflux conditions while stirring. Until the generation of hydrogen gas ceased, the reaction was performed under heating conditions to obtain a solid reaction product. The reaction liquid containing the solid reaction product was dried under reduced pressure to obtain a magnesium compound (diethoxymagnesium).
(2) Preparation of solid catalyst component In a catalytic reaction tank made of stainless steel having an internal volume of 500 liters sufficiently substituted with nitrogen gas, 16 kg of the magnesium compound obtained in (1) above, 80 liters of purified heptane, silicon tetrachloride 4 liters and 2.3 liters of di-n-butyl phthalate were charged. The system was maintained at 90 ° C., 77 liters of titanium tetrachloride was added with stirring, and the mixture was reacted at 110 ° C. for 2 hours. Then, the solid components were separated and washed with purified heptane at 80 ° C. Further, 122 liters of titanium tetrachloride was added and reacted at 110 ° C. for 2 hours, and then sufficiently washed with purified heptane to obtain a solid catalyst component.

(3) Preliminary polymerization In a polymerization reaction tank made of stainless steel with an internal volume of 80 liters sufficiently substituted with nitrogen gas, 4 kg of the solid catalyst component obtained in (2) above, 40 liters of purified heptane, 1.6 mol of triethylaluminum Then, 4.0 mol of cyclohexylmethyldimethoxysilane was charged, and the system was kept at 40 ° C., and propylene was continuously supplied for 2 hours while stirring. After stopping the supply of propylene, the temperature was kept at 40 ° C. for 30 minutes. Thereafter, it was washed with purified heptane to obtain a prepolymerized catalyst.
(4) Main polymerization After a 300 liter stainless steel autoclave reactor equipped with a stirrer was sufficiently replaced with nitrogen gas, 200 liters of liquid propylene, 120 mmol of triethylaluminum, and 0.012 mol of cyclohexylisobutyldimethoxysilane were added. The temperature in the reactor was raised to 55 ° C., and 0.16 mol% of hydrogen was supplied. Thereafter, 0.75 g of the titanium-containing polypropylene (preliminary polymerization catalyst) obtained by the preliminary polymerization of (3) above was added as a supported catalyst, and propylene was polymerized at 55 ° C. for 35 minutes.

Thereafter, ethylene was supplied and charged so that the ethylene gas concentration was 12.5 mol%. Supply was continued continuously so that the ethylene gas concentration was 12.5 mol%, and copolymerization of propylene and ethylene was performed at 55 ° C for 80 minutes. Thereafter, liquid propylene was evaporated to obtain white free flowing copolymer particles. The copolymer particles thus obtained had an ethylene content of 22.2% by mass, an MFR of 0.05 g / 10 min, and an amount of xylene-soluble components at room temperature (25 ° C.) of 54% by mass. .
Next, Irganox 1010 (Ciba Japan) 1500 ppm, Irgaphos 168 (Ciba Japan) 1000 ppm as an antioxidant, and DHT-4A (Kyowa) as a neutralizer were added to the obtained copolymer particles. Chemical Industry Co., Ltd.) 1500 ppm, and as a decomposing agent, Parkadox 14 (Kayaku Akzo Co., Ltd.) 400 ppm was mixed, and the same direction meshing twin screw extruder TEM35 (made by Kobe Steel Co., Ltd.) was used. The mixture was kneaded and granulated at a resin temperature of 250 ° C. to obtain pellets. The MFR of this pellet was 1.5 g / 10 minutes.

[Measurement method for physical properties, etc.]
(1) Pressure correction value:
The pressure correction value in the Bargley correction was measured for the four types of polypropylene resin compositions of the resins A to D. The pressure correction value in the Bargley correction can be measured based on a plastic flow characteristic test method using a capillary rheometer defined in “JIS K 7199”.
Specifically, with respect to the above-mentioned resin A, resin B, resin C, and resin D, capillograph type 1C (trade name, manufactured by Toyo Seiki Seisakusho Co., Ltd.) is used, and the respective shear pressure correction values are changed below. It measured on condition of this. The capillograph type 1C is widely used in related industries. When measurement is performed under the following conditions using this, the shear rate is 1216 s ⁻¹ .

Barrel diameter (inner diameter): 9.55 mm
Capillary diameter D: 1.0 mm
Piston extrusion speed: 100 mm / min
Measurement temperature: 210 ° C
Capillary diameter / length ratio L / D: 30/40/50

(2) Mass fraction of propylene polymer component (P1 component) and propylene polymer component (P2 component):
It calculated | required from the mass balance using the flowmeter integrated value of the propylene supplied continuously at the time of superposition | polymerization.
(3) Intrinsic viscosity [η]:
Measurements were made in a 135 ° C. tetralin solvent.
The intrinsic viscosity [η ₁ ] of the first stage (P1 component) of the propylene-based multistage polymer and the intrinsic viscosity [η _total ] of the entire propylene polymer are evaluated by sampling during the polymerization process. The intrinsic viscosity [η ₂ ] of the second stage (P2 component) was calculated by the following formula (IV).

[Η ₂ ] = ([η _total ] × 100− [η ₁ ] × W ₁ ) / W ₂ (IV)
[Η _total ]: The intrinsic viscosity of the entire propylene polymer (dL / g)
[Η ₁ ]: Intrinsic viscosity of P1 component (dL / g)
W ₁ : Mass fraction of P1 component (mass%)
W ₂ : P2 component mass fraction (% by mass)

(4) Melt flow rate (MFR):
In accordance with JIS K7210, the temperature was 230 ° C. and the load was 2.16 kgf (21.2 N).

(5) Foaming ratio:
The density was calculated by dividing the mass of the molded product by the volume determined by the submerging method, and calculated as the expansion ratio.

(6) Molding status:
The evaluation was based on whether or not the mold could be formed according to the shape of the mold.
○: Molded according to mold shape ×: Cannot be molded according to mold shape

[Evaluation of physical properties of resin]
FIG. 6 shows the result of measuring the pressure correction value of the above resin A, resin C, and resin D by the above method. FIG. 6 is a graph showing the relationship between the shear rate and the pressure correction value.

As shown in FIG. 6, the resin C and the resin D, which are conventional polypropylene resin compositions, have a shear rate of 1000 s ⁻¹ or less and the pressure correction value does not change significantly. On the other hand, the resin A has a shear rate of 1000 s ^-1 or less, and the pressure correction value increases rapidly. If the pressure correction value is large in the vicinity of 1000 s ⁻¹ , the elongation viscosity is high and the bubbles are not easily broken. Therefore, it can be said that the resin A has a higher elongation viscosity than the resins C and D, and a highly foamed foam can be obtained.

In addition, with respect to the above four types of resins, the measurement results of the pressure correction value (bargley correction) and the melt flow rate (MFR) at a shear rate of 1216 s ⁻¹ are shown below.

<Test 1>
As shown in Tables 2 and 3 below, a cylindrical extruded foam was formed with various chemical foaming agents using the four types of resins A to D, and after 30 seconds had elapsed, FIG. 7 and FIG. Was molded using a mold that was a flat dish-shaped molded body, and the molding situation and the appearance after molding were observed.

(1) Manufacturing apparatus and manufacturing conditions Extruder: Extruder manufactured by Mac International Associates (screw diameter: 45 mm)
Die: Cylindrical die (45 mm in diameter)
Extrusion amount: 10 kg / hr
Extruder: Cylinder set temperature 190 ° C
As a foaming agent, an inorganic chemical foaming agent “Polyslen EE405F” (trade name, manufactured by Eiwa Chemical Industry Co., Ltd.) (foaming agent A) or a foaming agent mainly composed of azodicarbonamide (foaming) with respect to 100 parts by mass of resin. Agent B) was contained in an appropriate amount (parts). The foaming agent B is a system in which 10 mL of liquid paraffin is added to 0.500 g of the foaming agent, and the amount of gas generated when the temperature is increased at a temperature increase rate of 2 ° C./min is 5 mL at 175 ° C. and 80 mL at 180 ° C. It is a foaming agent having gas generation characteristics.

(2) Manufacturing Method A mixture obtained by dry blending a resin raw material and a foaming agent is put into the hopper 110. And it sets to the predetermined | prescribed screw rotation speed of an extruder, fuse | melts a resin raw material within an extruder, is mixed with a foaming agent, and supplies a mixture to die | dye with fixed extrusion amount.
The supplied mixture was extruded vertically downward from the die 150 and foamed in the atmosphere. Then, the molds 161 and 162 are closed to sandwich the extruded foam, and the extruded foam is filled into a mold cavity configured with the molds 161 and 162 closed, and then molded. Then, the molds 161 and 162 are held closed, and the extruded foam is cooled and solidified in the molds 161 and 162. The mold temperature at this time was 40 ° C., and the solution was cooled and solidified for 30 seconds. Thereafter, the molds 161 and 162 are opened, and the extruded foam molded body 190 shown in FIGS. 7 and 8 is taken out. In addition, in this manufacturing method, since the chemical foaming agent is used, the gas introduction path 130 and the gear pump 140 shown in FIG. 1 are not attached.
The results are shown in Table 2 and Table 3 below.

As shown in Table 2, in Examples 1 to 9 using resins A and B, even when the wall shear rate was set to a low speed, the expanded foamed molded article had a foaming ratio exceeding 3 times, and the surface appearance was also good. It was good and the corners were firmly molded even after molding.
On the other hand, in Tables 1 to 4 in Table 3, sufficient foaming was not obtained. In Comparative Example 2, extrusion clearance foaming was performed by setting the die clearance as the wall surface shear rate recommended for the resin C, but sufficient foaming was not obtained, and the surface appearance was rough. In any of the comparative examples, the desired extruded foam having a sufficient thickness was not obtained, and the corner portion was not sufficiently molded in the mold molding, and the mold could not be molded.

  The polypropylene-based extruded foamed product of the present invention is excellent in light weight and heat insulation properties while taking advantage of the properties as a polypropylene-based resin, and is suitable for, for example, interior and exterior materials in the field of housing and automobiles, food trays, etc. It is.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows typically the extrusion foaming apparatus of one Embodiment of this invention. It is a schematic diagram which shows the shape of the die | dye concerning this embodiment, (A) is sectional drawing of die | dye, (B) is a side view by the side of die | dye exit. It is a schematic diagram which shows the metal mold | die shaping | molding apparatus concerning the said embodiment, (A) is sectional drawing of extrusion molding, (B) is sectional drawing of clamping, (C) Sectional drawing of the extrusion foaming molding after mold removal . It is a schematic diagram which shows the modification of die | dye concerning the said embodiment, (A) is sectional drawing of die | dye, (B) is a side view by the side of die | dye exit. It is a schematic diagram which shows the modification of die | dye concerning the said embodiment, (A) is sectional drawing of die | dye, (B) is a side view by the side of die | dye exit. The graph which shows the relationship between a shear rate and a pressure correction value. It is a perspective view which shows the setting dimension of the molded object to mold-mold. It is sectional drawing which shows the setting dimension of the molded object to mold-mold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Extrusion foaming apparatus 110 ... Hopper 120 ... Cylinder 130 ... Gas introduction path 140 ... Gear pump 150, 170, 180 ... Die 160 ... Mold molding apparatus 190 ... Polypropylene type extrusion foaming molding

Claims (10)

A melt-kneading process in which a mixture containing a polypropylene resin and a foam material is melt-kneaded in an extruder, and an extrusion foaming process in which the composition melt-kneaded in the melt-kneading process is extruded and foamed from a die to form an extruded foam. And a mold forming step of producing a polypropylene-based extruded foam molded body having a predetermined shape by molding the extruded foam formed in this extrusion foaming process, and a method for producing a polypropylene-based extruded foam molded body Because
The polypropylene-based resin has a pressure correction value of 4 MPa or more and a (B) melt flow rate (MFR) of 0 in a capillary flow test under the conditions of (A) a measurement temperature of 210 ° C. and a shear rate of 1216 s ^−1. .5 g / 10 min or more,
In the melt-kneading step, the foamed material is contained in the polypropylene resin under the condition that the expansion ratio of the extruded foamed molded article is 3 times or more,
In the molding step, at least the extruded foam before the inside is crystallized is molded by the mold, cooled and solidified, and then demolded to produce the polypropylene-based extruded foam. Method for producing a polypropylene-based extruded foam. A method for producing a polypropylene-based extruded foam molded article according to claim 1,
In the extrusion foaming step, when the composition is extruded and foamed, an apparent shear rate of the die wall surface at a portion where the die clearance is minimum in the vicinity of the die exit is set to 10 s ⁻¹ or more and 1000 s ⁻¹ or less. A method for producing a polypropylene-based extruded foam. It is a manufacturing method of the polypropylene-type extrusion foaming molding according to claim 1 or 2,
In the mold forming step, the extruded foam is molded within 60 seconds after the extrusion foaming step. A method for producing a polypropylene-based extruded foam molded product. A method for producing a polypropylene-based extruded foam molded body according to any one of claims 1 to 3,
A method for producing a polypropylene-based extruded foamed product, wherein the die has a slit or cylindrical outlet channel. A method for producing a polypropylene-based extruded foam molding according to any one of claims 1 to 4,
The set temperature of the die is 170 ° C. or higher and 210 ° C. or lower. A method for producing a polypropylene-based extruded foam molded product. A method for producing a polypropylene-based extruded foam molded body according to any one of claims 1 to 5,
In the extrusion foaming step, extrusion molding is performed into an extruded foam having a thickness of 2 mm or more and 30 mm or less. A method for producing a polypropylene-based extruded foam molding. A method for producing a polypropylene-based extruded foam molded body according to any one of claims 1 to 6,
In the melt-kneading step, the foamed material is contained in the polypropylene resin under the condition that the foaming ratio of the extruded foam is 3 times or more and 10 times or less. . A method for producing a polypropylene-based extruded foam molded body according to any one of claims 1 to 7,
The expansion ratio of the polypropylene-based extruded foam molded product is 3 times or more and 10 times or less. A polypropylene-based extruded foam molded article obtained by melt-kneading a mixture containing a polypropylene-based resin and a foamed material in an extruder, extruded and foamed from a die, and then molded into a predetermined shape by a mold,
The polypropylene-based resin has a pressure correction value of 4 MPa or more and a (B) melt flow rate (MFR) of 0 in a capillary flow test under the conditions of (A) a measurement temperature of 210 ° C. and a shear rate of 1216 s ^−1. .5 g / 10 min or more,
The polypropylene resin containing the foamed material was extruded and foamed under a condition that the expansion ratio was 3 to 10 times, and was molded by the mold and cooled and solidified at least before the inside was crystallized. A featured polypropylene-based extruded foam. The polypropylene-based extruded foam molded article according to claim 9,
A polypropylene-based extruded foamed product having a foaming ratio of 3 to 10 times.

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