JP2007119760A - Propylene-based polymer and molded foam product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a propylene-based polymer able to form a molded foam product having microcells in high expansion ratio. <P>SOLUTION: The polypropylene-based polymer has ≥0.1g/10 minutes melt flow rate (at 230°C, 2.16kg load) and satisfies equation (1) [wherein η<SB>e</SB>expresses viscosity of the propylene-based polymer, ε expresses a strain rate and η<SB>e</SB>is a measured value when ε is 10sec<SP>-1</SP>and 100sec<SP>-1</SP>]. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a propylene-based polymer and a foamed molded product.

  Propylene-based polymer foam products have been used in various fields, taking advantage of their heat resistance, oil resistance and environmental suitability. In the low foaming field where the foaming ratio is about 3 times, such as an extruded foam sheet, the foaming performance is improved by increasing the strain hardening property of the uniaxial elongational viscosity of the propylene polymer. On the other hand, in the high foaming field of several tens of times, the propylene-based polymer for ordinary foamed sheets is insufficient in foaming performance, and a polymer having excellent foaming performance is desired.

For such a material, for example, a copolymerization of a non-conjugated diene and propylene is disclosed (for example, see Patent Document 1). In addition, a technique for producing a long-chain branched PP is disclosed (for example, see Patent Documents 2-6). Furthermore, a method for imparting a high molecular weight component by prepolymerization is disclosed (for example, see Patent Documents 7 to 10).
However, polypropylene (PP) produced by these techniques has a large strain-hardening property of uniaxial elongation viscosity, and a low-foamed product with a foaming ratio of about 3 times can be molded, but a high foaming of about 30 times with carbon dioxide or the like. Failed to obtain a product.

Moreover, although the method (refer patent document 11) of blending the component from which molecular weight differs greatly is examined, the gel occurred frequently and was inferior to the commercial property as a foamed product.
Moreover, the method of providing a high molecular weight component by multistage polymerization is disclosed (for example, refer patent document 12-19).
In this technique, a method of applying a high molecular weight component using two or more polymerization tanks with an MgCl ₂ supported catalyst is performed.
However, the increase in the molecular weight of the high molecular weight component is insufficient, the strain hardening property of the uniaxial elongation viscosity is not greatly improved, and as a result, the foaming performance is not greatly improved as compared with general PP.
Japanese Patent Laid-Open No. 06-080729 Japanese translation of PCT publication No. 2002-542360 JP 2000-309670 A JP 2000-336198 A JP 2002-012717 A JP 2002-363355 A Special table 2002-509575 gazette JP-A-10-279632 JP-A-11-315178 JP 2000-143866 A JP 2002-309049 A JP 2001-247616 A JP 2001-048916 A JP 2001-055413 A JP 59-172507 A JP 05-239149 A JP 07-138323 A JP 11-228629 A JP 2000-226478 A

  The present invention has been made in view of the above problems, and a propylene-based polymer capable of obtaining a foamed molded body having high foaming and fine cells (for example, a foaming ratio of 30 times and a particle size of 100 μm or less). The purpose is to provide.

In order to achieve the above object, as a result of intensive studies, the present inventors have found that propylene-based polymers for the high foaming field have important properties different from general ones.
That is, in general, in the foam molding of a propylene-based polymer, it is said that the greater the strain hardening property of the uniaxial elongation viscosity obtained by a Meissner type apparatus or the like, the better the foam molding property. The strain rate measurable with a Meissner type apparatus or the like is a low speed region of about 3 sec ^{-1 at the} maximum. However, in foam molding in which a large amount of gas such as supercritical gas foam is dissolved, the strain rate at the time of cell growth is several hundred sec- ¹ or more, and the uniaxial elongation viscosity obtained by a Meissner type apparatus etc. Is not relevant.
As a result of extensive studies, the present inventors have found that there is a relationship between the elongation viscosity at the time of high-speed elongation obtained by the Cogswell method and the like and the moldability of foam molding in which a large amount of gas such as supercritical gas foaming is dissolved.

［式中、η_ｅはプロピレン系重合体の伸張粘度、εは歪速度である。η_ｅはεが１０ｓｅｃ^−１及び１００ｓｅｃ^−１での測定値である。］
２．前記プロピレン系重合体がプロピレン系多段重合体である１記載のプロピレン系重合体。
３．前記プロピレン系多段重合体が下記（Ａ）及び（Ｂ）を含む２記載のプロピレン系重合体。
（Ａ）１３５℃、テトラリン中での極限粘度［η］が１０ｄＬ／ｇ超のプロピレン単独重合体成分又はプロピレンと炭素数２〜８のα−オレフィンとの共重合体成分：２０〜３０重量％
（Ｂ）１３５℃、テトラリン中での極限粘度［η］が０．５〜３．０ｄＬ／ｇのプロピレン単独重合体成分又はプロピレンと炭素数２〜８のα−オレフィンとの共重合体成分：７０〜８０重量％
４．前記プロピレン系多段重合体が、１段階目の重合工程にて水素不存在下でプロピレンを重合又はプロピレンと炭素数２〜８のα−オレフィンを共重合させたものである３記載のプロピレン系重合体。
５．上記１〜４のいずれかに記載のプロピレン系重合体からなる、発泡倍率が３０倍以上の発泡成形体。 According to the present invention, the following propylene-based polymers and the like are provided.
1. A propylene polymer having a melt flow rate (230 ° C., load 2.16 kg) larger than 0.1 g / 10 min and satisfying the following formula (1).

[Where η _e is the extensional viscosity of the propylene polymer, and ε is the strain rate. eta _e is ε is measured at 10 sec ^-1 and 100 sec ^-1. ]
2. 2. The propylene polymer according to 1, wherein the propylene polymer is a propylene multistage polymer.
3. 3. The propylene polymer according to 2, wherein the propylene multistage polymer includes the following (A) and (B).
(A) Propylene homopolymer component having intrinsic viscosity [η] in tetralin of 135 ° C. or more than 10 dL / g or copolymer component of propylene and α-olefin having 2 to 8 carbon atoms: 20 to 30% by weight
(B) Propylene homopolymer component having intrinsic viscosity [η] in tetralin of 135 ° C. and 0.5 to 3.0 dL / g or copolymer component of propylene and α-olefin having 2 to 8 carbon atoms: 70-80% by weight
4). 4. The propylene-based heavy polymer according to 3, wherein the propylene-based multistage polymer is obtained by polymerizing propylene or copolymerizing propylene and an α-olefin having 2 to 8 carbon atoms in the absence of hydrogen in the first polymerization step. Coalescence.
5. A foamed molded article having a foaming ratio of 30 times or more, comprising the propylene-based polymer according to any one of 1 to 4 above.

  In the present invention, it is possible to provide a propylene-based polymer from which a foamed molded product having high foaming and fine cells can be obtained.

［式中、η_ｅはプロピレン系重合体の伸張粘度、εは歪速度である。η_ｅはεが１０ｓｅｃ^−１及び１００ｓｅｃ^−１での測定値である。］ Hereinafter, the propylene polymer of the present invention will be specifically described.
The propylene polymer of the present invention has a melt flow rate (MFR: 230 ° C., load 2.16 kg) larger than 0.1 g / 10 min and satisfies the following formula (1).

[Where η _e is the extensional viscosity of the propylene polymer, and ε is the strain rate. eta _e is ε is measured at 10 sec ^-1 and 100 sec ^-1. ]

  When MFR <0.1 g / 10 min, extrusion molding may be difficult. Preferably, 0.5 g / 10 minutes ≦ MFR ≦ 5 g / 10 minutes, and more preferably 1.0 g / 10 minutes ≦ MFR ≦ 2.0 g / 10 minutes.

When the relationship of the above formula (1) is not satisfied, a foamed product with a high expansion ratio having fine cells cannot be obtained.
5.6 which is a constant term in Formula (1) becomes like this. Preferably it is 5.8, More preferably, it is 6.0 or more. If it is less than 5.6, a foamed molded product having 30 times or more high foaming and a fine cell of 100 μm or less cannot be obtained.
0.8 which is a multiplier in the formula (1) is preferably 0.7. When the ratio is larger than 0.8, a foamed molded article having 30 times or more highly foamed and 100 μm or less fine cells cannot be obtained.

In the formula (1), the extensional viscosity (η _e ) and strain rate (ε) of the propylene polymer are values obtained by the Cogswell method. Details will be described in an embodiment described later. Incidentally, the extensional viscosity (eta _e) is strain rate (epsilon) is directed to the measurement of time is 10 sec ^-1 or more, in the actual measurement, the measurement for two points 10 sec ^-1 and 100 sec ^-1 do it.

Hereinafter, as an example of a method for producing the propylene-based polymer of the present invention, a method by a multistage polymerization method will be described.
Examples of the propylene polymer satisfying the requirements of MFR and formula (1) described above include propylene-based multistage polymers including the following (A) and (B).
(A) Propylene homopolymer component having intrinsic viscosity [η] in tetralin of 135 ° C. or more than 10 dL / g or copolymer component of propylene and α-olefin having 2 to 8 carbon atoms: 20 to 30% by weight
(B) Propylene homopolymer component having intrinsic viscosity [η] in tetralin of 135 ° C. and 0.5 to 3.0 dL / g or copolymer component of propylene and α-olefin having 2 to 8 carbon atoms: 70-80% by weight
This multi-stage polymer polymerizes propylene in two or more polymerization steps using the following components (a) and (b), or olefin polymerization catalysts consisting of the following components (a), (b) and (c). Alternatively, it can be produced by 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), examples of the organoaluminum compound that reduces titanium tetrachloride include (a) alkylaluminum dihalide, specifically, methylaluminum dichloride, ethylaluminum dichloride, and n-propylaluminum dichloride, (B) Alkyl aluminum sesquihalide, specifically, ethylaluminum sesquichloride, (c) Dialkylaluminum halide, specifically, dimethylaluminum chloride, diethylaluminum chloride, di-n-propylaluminum chloride, and diethylaluminum bromide (D) trialkylaluminum, specifically, trimethylaluminum, triethylaluminum, and triisobutylaluminum, (e) dialkyl Rumi bromide 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 to obtain titanium trichloride is usually carried out in the temperature range of −60 to 60 ° C., preferably −30 to 30 ° C. When the temperature is below the above temperature range, a long time is required for the reduction reaction, and when the temperature is above the temperature, it is not preferable because partial reduction occurs partially. 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 (a), the treatment with the ether compound of titanium trichloride and the electron acceptor may be carried out using a mixture of both treatment agents, and after treatment with one, treatment with the other. You may go. 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 treatment temperature in the ether treatment is preferably 0 to 100 ° C. Although it does not restrict | limit especially about processing time, Usually, it carries out in the range of 20 minutes-5 hours.

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. When the amount of the ether compound used is less than the above range, the stereoregularity of the produced polymer cannot be sufficiently improved, which is not preferable. Moreover, when the said range is exceeded, although the stereoregularity of a production | generation polymer can fully be improved, since a yield will fall, it is unpreferable. Strictly speaking, titanium trichloride treated with an organoaluminum compound or an ether compound is a composition mainly composed of titanium trichloride.
In the present invention, Solvay type titanium trichloride can be suitably used as such a solid catalyst component (a).

  Examples of the organoaluminum compound (b) include the same compounds as described above.

  Examples of the cyclic ester compound (c) include γ-lactone, δ-lactone, ε-lactone, and the like. Of these, ε-lactone is preferable.

  The olefin polymerization catalyst used in the production of the propylene polymer can be prepared by mixing the components (a) to (c).

In this production method, it is preferable to polymerize propylene or copolymerize propylene and an α-olefin having 2 to 8 carbon atoms in the absence of hydrogen in the first stage of the two or more polymerization steps.
By carrying out the polymerization of propylene or the copolymerization of propylene and α-olefin in the absence of such hydrogen, the ultrahigh molecular weight propylene polymer, that is, the component (A) in the multistage polymer of the present invention is produced. be able to. Moreover, in the manufacturing method of this invention, it is preferable to manufacture the (B) component of a multistage polymer in the 2nd stage or later. The reason for this will be described below.

  The propylene-based multistage polymer has a large molecular weight difference between a high molecular weight component and a low molecular weight component, and there is a problem in the amount of fish eye generated. Furthermore, when manufacturing by a continuous polymerization method, the composition unevenness between polymerization particles arises by residence time distribution, and the amount of fish eye generation | occurrence | production increases more. On the other hand, comparing the polymerization reaction rate in the high molecular weight component and the low molecular weight component, in other words, in the absence of hydrogen and in the presence of hydrogen, the latter is several times faster. Therefore, when this low molecular weight component polymerization reaction is performed in the first stage polymerization step, the polymerization reaction rate is remarkably increased without deactivation due to the polymerization history, so the residence time is shortened to adjust the reaction amount ratio. Need to do. As a result, the presence of catalyst particles that short-pass the first-stage polymerization reaction is increased, and the composition unevenness among the polymer particles becomes more intense than when the high-molecular weight component is polymerized in the first stage. This is because the composition unevenness significantly deteriorates the dispersibility of the high molecular weight component, impairs the effect of improving the melt tension, and may lower the foaming characteristics of the obtained propylene-based multistage polymer.

  Note that “in the absence of hydrogen” means substantially in the absence of hydrogen, and includes not only the case where no hydrogen is present at all, but also the case where a very small amount of hydrogen is present (for example, about 10 molppm). In short, even in the case where hydrogen is contained to the extent that the intrinsic viscosity of the first stage propylene polymer or propylene copolymer measured in 135 ° C. tetralin does not become 10 dL / g or less, “in the absence of hydrogen” Included in the meaning.

In the production method of the present invention, the production conditions for the component (A) are as follows. In the absence of hydrogen, the raw material monomer is the polymerization temperature, preferably 20 to 80 ° C., more preferably 40 to 70 ° C., and the polymerization pressure is generally It is preferably produced by slurry polymerization under conditions of normal pressure to 1.47 MPa, preferably 0.39 to 1.18 MPa.
In addition, the production conditions for the component (B) are not particularly limited except that the above olefin polymerization catalyst is used, but the raw material monomer is preferably 20 to 80 ° C., more preferably 60 to 70 ° C. as the polymerization temperature. The polymerization pressure is generally from atmospheric pressure to 1.47 MPa, preferably from 0.19 to 1.18 MPa, and it is preferable to carry out the polymerization under conditions where hydrogen as a molecular weight regulator exists.

Under the above conditions, by appropriately adjusting the reaction time and the like, in the first stage polymerization step, propylene homopolymer component having an intrinsic viscosity [η] in tetralin of 135 ° C. and greater than 10 dL / g, or propylene A copolymer component with an α-olefin having 2 to 8 carbon atoms is produced in an overall polymer in an amount of 20 to 30% by weight, and the intrinsic viscosity [η] in tetralin at 135 ° C. in the second stage polymerization step. The propylene homopolymer component having a molecular weight of 0.5 to 3.0 dL / g or the copolymer component of propylene and an α-olefin having 2 to 8 carbon atoms is produced in an amount of 70 to 80% by weight in the whole polymer.
In addition, it is preferable that (A) component is 22 to 28 weight% in all the polymers, and it is preferable that intrinsic viscosity [(eta)] is 12 to 18 dL / g.
Moreover, it is preferable that (B) component is 73 to 77 weight% in all the polymers, and it is preferable that intrinsic viscosity [(eta)] is 1.0-2.0 dL / g.

  In this production method, preliminary polymerization may be performed before the main polymerization. When the prepolymerization is performed, the powder morphology can be maintained well. In the prepolymerization, generally, the polymerization temperature is preferably 0 to 80 ° C., more preferably 10 to 60 ° C., and the polymerization amount is preferably 0.001 to 100 g, more preferably 0. It is preferable to polymerize 1 to 10 g of propylene or copolymerize propylene and an α-olefin having 2 to 8 carbon atoms.

In addition to the multistage polymer described above, examples of the propylene polymer of the present invention include the following.
1. 1. High molecular weight propylene polymer containing ultrahigh molecular weight polyethylene 2. A modified propylene polymer having a high molecular weight using a crosslinking peroxide; 3. High molecular weight one-side free-end long-chain branched propylene polymer and crosslinked propylene polymer by electron beam irradiation or the like A long-chain branched propylene polymer having a high molecular weight obtained by copolymerizing a non-conjugated diene or the like. In these propylene polymers, the MFR and the above formula (1) are adjusted by appropriately adjusting the blending amount of the additive, the processing time, and the like. Can be met.

The propylene-based polymer of the present invention can be molded by various molding methods such as extrusion molding, injection molding, foam molding, hollow molding and the like. Preferably, it shape | molds by foam molding, such as extrusion foam molding.
When foaming the propylene polymer of the present invention, various foaming agents such as carbon dioxide, butane, nitrogen, baking soda and the like can be used.
When injection-molding the multistage polymer or composition of the present invention, it is preferable to use supercritical carbon dioxide or supercritical nitrogen as a foaming agent.
Since the propylene-based polymer of the present invention is particularly excellent as a resin for high foam molding, the expansion ratio of the obtained injection foam molded article and extruded foam molded article can be 30 times or more. It is also possible to manufacture a foamed molded product of 30 times or less.

In forming the propylene-based polymer, additives such as an antioxidant, a neutralizing agent, a flame retardant and the like can be used as necessary. The ratio of the additive is not particularly limited and can be adjusted as appropriate.
Moreover, you may mix | blend a silica, activated carbon, a zeolite, a silica gel, or fibrous activated carbon as a powder or a fibrous porous filler.
Also, as a decomposable foaming agent, a bicarbonate such as sodium bicarbonate, an organic acid such as citric acid or a combination thereof, or an organic foaming agent such as azodicarbonamide or dinitrosopentamethylenetetramine may be blended. Good. These foaming agents can be used alone or in combination of two or more. Moreover, talc, sodium bicarbonate, citric acid, etc. can also be added as a bubble regulator.
Moreover, you may mix | blend talc, organic carboxylate, organic phosphate, and a sorbitol type | system | group nucleating agent as a crystallization nucleating agent.

Hereinafter, the present invention will be described more specifically with reference to examples.
In each example, the sample was evaluated or prepared by the following method.
(1) Weight fraction of the first stage propylene polymer component (component A) and the second stage propylene polymer component (component B) Material balance using flow meter integrated value of propylene continuously supplied during polymerization I asked for it.

(2) Intrinsic viscosity [η]
Performed at 135 ° C. in tetralin.
The intrinsic viscosity [η] ₂ of component B is a value calculated from the following formula.
[Η] ₂ = ([η] _total × 100− [η] ₁ × W ₁ ) / W ₂
[Η] _total : Intrinsic viscosity of the entire propylene polymer [η] ₁ : Intrinsic viscosity of component A W ₁ : Weight fraction (% by weight) of component A
W ₂ : Weight fraction of component B (% by weight)

(3) Melt flow rate (MFR)
According to JIS K7201, the measurement was performed at a temperature of 230 ° C. and a load of 2.16 kgf.
(4) Foaming ratio The foaming ratio of the foamed molded product was calculated by calculating the density by dividing the weight of the molded product by the volume determined by the submerging method.
(5) Average cell diameter of foam-molded article Measured according to ASDM D3576-3577.

(6) Production of propylene polymer pellets With respect to 100 parts by weight of the obtained propylene polymer, Irganox 1010 (trade name, manufactured by Ciba Specialty Chemicals) 0.15 parts by weight, Irgafos 168 ( 0.15 parts by weight of trade name, manufactured by Ciba Specialty Chemicals Co., Ltd., 0.06 parts by weight of calcium stearate, 0.06 parts by weight of DHT-4A (trade name, Kyowa Chemical Industry Co., Ltd.) In addition, they were mixed, melt kneaded and granulated at 230 ° C. with a Laboplast mill single screw extruder (20 mmφ) manufactured by Toyo Seiki Co., Ltd.

(7) Molding of foam molded product The foam molded product was obtained by simply extruding from the following injection molding machine using the pellets prepared in (5) above.
Molding machine: Japan Steel, J180EL-MuCell
Injection time: 5 seconds Cylinder set temperature: 180 ° C
Gas amount: 7wt% (carbon dioxide)
In addition, what mixed 0.5 part of foaming agents (Eiwa Chemical Co., Ltd. product, EE205) with respect to 100 weight part of said pellets was used.

［式中、τ_ｗはせん断応力（単位：Ｐａ）、γはせん断速度（単位：ｓｅｃ^−１）、ｎはｎ値、ΔＰ_ｅは入り口流入圧（単位：Ｐａ）である。］ (8) Calculation Method of Formula (1) 8-1 Cogswell Method Elongation Viscosity In formula (1), the elongation viscosity (η _e : unit: Pa · s) and strain rate (ε: unit: sec ⁻¹ ) of the propylene polymer. ) Is calculated by the following formulas (2) and (3), respectively.

Wherein, tau _w is the shear stress (unit: Pa), gamma is the shear rate ^{(unit: sec} -1), n is n value, the [Delta] P _e entrance inflow pressure (unit: Pa) is. ]

The shear stress and shear rate were 30/1, 40/1, 50/1 with a capillary rheometer (Capillograph 1B manufactured by Toyo Seiki Co., Ltd.) at a measurement temperature of 230 ° C. and an orifice (length / diameter: mm). Measurements were made using three tubes. The n value and the inlet inflow pressure were calculated as follows.
・ Calculation of inlet inflow pressure ΔPe Calculate the primary expression of capillary length and pressure loss from the data of three pressure loss at the same shear rate measured at each orifice, and the value (intercept) at 0 mm length is the inlet inflow pressure. ΔPe.
-Calculation of n value By subtracting the inlet inflow pressure from the pressure value of the orifice 50/1 (mm), the pressure required for the true flow was determined to determine the shear stress (Balay correction). The slope n was obtained by linearly approximating log (shear rate) and log (shear stress).

Example 1
(1) Prepolymerization A three-necked flask with an internal volume of 5 liters equipped with a stirrer was thoroughly dried and replaced with nitrogen gas. 20 g of a 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.

(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 while 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. The polymer production amount obtained from the propylene flow rate integrated value when propylene was continuously supplied for 1.7 hours was 1150 g. As a result of sampling and analyzing a part thereof, the intrinsic viscosity was 15.4 dL / g. It was. 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. Polymerization was carried out at 65 ° C. for 4 hours while continuously supplying propylene at a total pressure of 0.78 MPa. At this time, as a result of sampling and analyzing a part of the polymer, the intrinsic viscosity was 4.94 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 3.4 kg of a propylene polymer.
As a result, the weight ratio of the first stage and second stage polymerization components was 25.3: 74.7, and the intrinsic viscosity of the polymer produced in the second stage was 1.40 dL / g. I was asked.

(3) Granulation, foam molding, evaluation The above-mentioned additives were added to the obtained powdery propylene polymer, and pelletizing and foam molding were performed. Further, the high strain rate region pellets 100 g (epsilon is the case of 10 sec ^-1 and 100 sec ^-1) was measured elongation viscosity.
Table 1 shows the physical properties, resin characteristics, and properties of the foamed molded product of Example 1 and the polymers of Examples 2 and 3 and Comparative Examples 1 to 3 described later.

Example 2
Polymerization was carried out in the same manner as in Example 1 except that the polymerization time for the first stage was 1.4 hours in the propylene polymerization. As a result, 3.4 kg of a propylene polymer was obtained. At this time, the polymerization weight ratio of the first stage and the second stage is 22.2: 77.8, and the intrinsic viscosity of the polymer produced in the first stage is 15.8 dL / g. The intrinsic viscosity of the polymer produced in 1) was determined to be 1.42 dL / g.

Example 3
Polymerization was carried out in the same manner as in Example 1 except that the polymerization time for the first stage was 2.4 hours in the propylene polymerization. As a result, 3.5 kg of a propylene polymer was obtained. At this time, the polymerization weight ratio of the first stage and the second stage was 29.0: 71.0, and the intrinsic viscosity of the polymer produced in the first stage was 14.6 dL / g. The intrinsic viscosity of the polymer produced in 1) was determined to be 1.45 dL / g.

Comparative Example 1
Polymerization was carried out in the same manner as in Example 1 except that the propylene polymerization time was 1.0 hour in the first stage. As a result, 3.3 kg of a propylene polymer was obtained. The polymerization weight ratio of the first stage and the second stage at this time is 16.9: 83.1, and the intrinsic viscosity of the polymer produced in the first stage is 15.4 dL / g, and the second stage The intrinsic viscosity of the polymer produced in 1) was determined to be 1.38 dL / g.

Comparative Example 2
(1) Prepolymerization A prepolymerization catalyst component was obtained in the same manner as in Example 1 (1).

(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.
Subsequently, 0.01 MPa of hydrogen was introduced, and then propylene was introduced with stirring. After the system was stabilized at an internal temperature of 60 ° C. and a total pressure of 0.78 MPa, the prepolymerized catalyst component was converted into a solid catalyst. The polymerization was started by adding 400 ml of heptane slurry containing 1.5 grams. Propylene was continuously fed for 4 hours.
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 3.8 kg of a propylene polymer.
The intrinsic viscosity of this polymer was 4.1 dL / g.

Comparative Example 3
Polymerization was carried out in the same manner as in Example 1 except that the polymerization temperature of the first stage was 40 ° C., the polymerization time was 5.0 hours, and the polymerization time of the second stage was 3 hours. As a result, 2.4 kg of a propylene polymer was obtained. At this time, the polymerization weight ratio of the first stage and the second stage was 41.3: 58.7, and the intrinsic viscosity of the polymer produced in the first stage was 17.9 dL / g. The intrinsic viscosity of the polymer produced in 1) was determined to be 1.43 dL / g.

Example 4
(1) Prepolymerization A prepolymerization catalyst component was obtained in the same manner as in Example 1 (1).

(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 40 ° 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. The polymer production amount obtained from the propylene flow rate integrated value when propylene was continuously supplied for 2.2 hours was 1190 g. As a result of sampling and analyzing a part thereof, the intrinsic viscosity was 19.7 dL / g. It was. 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. Polymerization was carried out at 65 ° C. for 5.2 hours while continuously supplying propylene at a total pressure of 0.78 MPa. At this time, as a result of sampling and analyzing a part of the polymer, the intrinsic viscosity was 5.2 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 4.44 kg of a propylene polymer.
As a result, the weight ratio of the first stage and second stage polymerization components was 21.1: 78.9, and the intrinsic viscosity of the polymer produced in the second stage was 1.44 dL / g. I was asked.

(3) Granulation, foam molding, evaluation It carried out like Example 1 (3).
Table 2 shows the physical properties, resin characteristics, and properties of the foamed molded product of Example 4 and the polymers of Examples 5 and 6 described later.

Example 5
(1) Prepolymerization A prepolymerization catalyst component was obtained in the same manner as in Example 1 (1).

(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 65 ° 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. The polymer production amount obtained from the propylene flow rate integrated value when propylene was continuously supplied for 1.7 hours was 1190 g. As a result of sampling and analyzing a part thereof, the intrinsic viscosity was 12.1 dL / g. It was. 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. Polymerization was carried out at 65 ° C. for 5.1 hours while continuously supplying propylene at a total pressure of 0.78 MPa. At this time, as a result of sampling and analyzing a part of the polymer, the intrinsic viscosity was 3.63 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 4.44 kg of a propylene polymer.
As a result, the weight ratio of the first stage and second stage polymerization components was 21.1: 78.9, and the intrinsic viscosity of the polymer produced in the second stage was 1.39 dL / g. I was asked.

Example 6
(1) Prepolymerization A prepolymerization catalyst component was obtained in the same manner as in Example 1 (1).

(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 65 ° 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. The polymer production amount obtained from the integrated value of the propylene flow rate when propylene was continuously supplied for 2.2 hours was 1160 g. As a result of sampling and analyzing a part thereof, the intrinsic viscosity was 11.9 dL / g. It was. 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. Polymerization was performed at 65 ° C. for 3.5 hours while propylene was continuously supplied at a total pressure of 0.78 MPa. At this time, as a result of sampling and analyzing a part of the polymer, the intrinsic viscosity was 4.32 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 3.0 kg of a propylene polymer.
As a result, the weight ratio of the first stage and second stage polymerization components was 28.0: 72.0, and the intrinsic viscosity of the polymer produced in the second stage was 1.40 dL / g. I was asked.

  The propylene polymer of the present invention can be suitably used in the fields of foamed sheets, building materials, automobile members and the like because a molded body having fine cells can be obtained at a high expansion ratio (for example, 30 times or more).

Claims (5)

A propylene polymer having a melt flow rate (230 ° C., load 2.16 kg) larger than 0.1 g / 10 min and satisfying the following formula (1).

[Where η _e is the extensional viscosity of the propylene polymer, and ε is the strain rate. eta _e is ε is measured at 10 sec ^-1 and 100 sec ^-1. ]   The propylene-based polymer according to claim 1, wherein the propylene-based polymer is a propylene-based multistage polymer. The propylene-based polymer according to claim 2, wherein the propylene-based multistage polymer contains the following (A) and (B).
(A) Propylene homopolymer component having intrinsic viscosity [η] in tetralin of 135 ° C. or more than 10 dL / g or copolymer component of propylene and α-olefin having 2 to 8 carbon atoms: 20 to 30% by weight
(B) Propylene homopolymer component having intrinsic viscosity [η] in tetralin of 135 ° C. and 0.5 to 3.0 dL / g or copolymer component of propylene and α-olefin having 2 to 8 carbon atoms: 70-80% by weight   4. The propylene according to claim 3, wherein the propylene-based multistage polymer is obtained by polymerizing propylene or copolymerizing propylene and an α-olefin having 2 to 8 carbon atoms in the absence of hydrogen in the first polymerization step. Polymer. A foamed molded article comprising the propylene-based polymer according to any one of claims 1 to 4 and having an expansion ratio of 30 times or more.