Ultra-high molecular weight propylene polymers (copolymers)

Abstract

An ultra-high molecular weight propylene polymer (copolymer), which is a propylene homopolymer or a copolymer of propylene and 30 wt% or less of an alpha-olefin having 2 or 4 to 8 carbon atoms, and which has an intrinsic viscosity of greater than 20 dl / g as measured in a tetralin solvent at 135 DEG C.

Description

[0001] This application is a divisional application. The Chinese national application number of the application to which it is directed is 202080043566.6, the international application number is PCT / JP2020 / 023195, the application date is June 12, 2020, the date of entry into China is December 14, 2021, and the name of the invention is “Ultra-high molecular weight propylene polymer (copolymer)”. Technical Field

[0002] The present invention relates to an ultra-high molecular weight propylene polymer (copolymer). Background Art

[0003] High molecular weight propylene polymers are particularly useful as resin components of extrusion molded products (ordinary sheets, foamed sheets, blow molded products, etc.), and various studies have been conducted on the production of high molecular weight propylene polymers. For example, Patent Document 1 discloses a cross-linked ultra-high molecular weight olefin polymer having an intrinsic viscosity [η] of 5 to 50 dl / g measured in a decalin solvent at 135°C. However, the olefin polymer specifically disclosed in the examples is only polyethylene. Patent Document 2 discloses an ultra-high molecular weight propylene homopolymer having an intrinsic viscosity [η] of 7 dl / g or more and less than 25 dl / g measured using a decalin solution. In the examples of this document, a propylene polymer having [η] of 20.2 dl / g is disclosed. Patent Document 3 discloses an ultra-high molecular weight polypropylene having an intrinsic viscosity [η] of at least 5 dl / g measured using a decalin solution. In the examples of this document, a polypropylene having [η] of 20.25 dl / g is disclosed. Patent Document 4 discloses a polypropylene having an intrinsic viscosity [η] of 5 to 20 dl / g as measured in a tetralin solvent at 135°C.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1 Japanese Patent No. 5979985

[0007] Patent Document 2 Japanese Patent No. 5653761

[0008] Patent Document 3 Japanese Patent No. 3023382

[0009] Patent Document 4 Japanese Patent No. 6144045 Summary of the invention

[0010] Problems to be solved by the invention

[0011] Patent Document 1 does not specifically disclose a propylene polymer having a high [η] value. Patent Documents 2 and 3 disclose a propylene polymer having an [η] of about 20 dl / g, and the viscosity is a value measured using decalin as a solvent. It is obvious to a person skilled in the art that when the value of [η] measured using decalin as a solvent is converted to a value measured using tetralin as a solvent, the value becomes lower. Therefore, when the [η] recorded in Patent Documents 2 and 3 is converted to a value measured using tetralin as a solvent, it is less than 20 dl / g. As can be seen from the above, there has been no report to date of an ultra-high molecular weight propylene polymer having an [η] greater than 20 dl / g measured using tetralin as a solvent. In view of this situation, the subject of the present invention is to provide an ultra-high molecular weight propylene polymer.

[0012] Solutions to Solve Problems

[0013] The present inventors have found that the ultrahigh molecular weight polypropylene polymer can be produced by optimizing the polymerization catalyst or polymerization conditions, thereby completing the present invention. That is, the above-mentioned problems are solved by the following present invention.

[0014] [1] A propylene homopolymer or a copolymer of propylene and 30% by weight or less of an α-olefin having 2 or 4 to 8 carbon atoms, wherein the intrinsic viscosity measured in a tetralin solvent at 135°C is greater than 20 dl / g.

[0015] [2] The copolymer according to [1], wherein the α-olefin is ethylene.

[0016] [3] The copolymer according to [2], wherein the intrinsic viscosity is 23 dl / g or more and the ethylene content is 3 to 30% by weight.

[0017] [4] The copolymer according to [2] or [3], wherein

[0018] The melting point Tm (°C) of the copolymer determined by DSC at a heating rate of 10°C / min and the ethylene content C2 (wt%) in the copolymer satisfy the following formula (1):

[0019] Tm≥-3.4×C2+162...(1)

[0020] [5] A method for producing a polymer, which is the method for producing a polymer according to any one of [1] to [4], comprising the following steps:

[0021] Using (A) a solid catalyst containing magnesium, titanium, halogen and an electron donor compound as essential components,

[0022] (B) an organoaluminum compound, and

[0023] The catalyst (C) containing an external electron donor compound as required is prepared by polymerizing the corresponding monomers.

[0024] [6] A polypropylene resin composition comprising the polymer described in any one of [1] to [4], wherein:

[0025] The content ratio of the polymer is 0.1 to 20% by weight relative to the total weight of the resin components constituting the composition.

[0026] Effects of the Invention

[0027] According to the present invention, there is provided an ultra-high molecular weight propylene polymer. DETAILED DESCRIPTION

[0028] Hereinafter, the present invention will be described in detail. In the present invention, "X to Y" includes the end values ​​X and Y.

[0029] 1. Propylene polymer (copolymer)

[0030] (1) Intrinsic viscosity

[0031] The propylene homopolymer or copolymer of propylene and 30% by weight or less of an α-olefin having 2 or 4 to 8 carbon atoms (hereinafter collectively referred to as "propylene polymer (copolymer)") of the present invention has an intrinsic viscosity of more than 20 dl / g measured in a tetralin solvent at 135°C. The intrinsic viscosity is an indicator of molecular weight, and the propylene polymer (copolymer) of the present invention has an unprecedentedly high molecular weight. Since the melt tension of the resin composition containing the propylene polymer (copolymer) having a high intrinsic viscosity is also increased, it is possible to provide, for example, an excellent foam. From this viewpoint, the lower limit of the intrinsic viscosity is preferably greater than 23 dl / g. In addition, from the viewpoint of ease of manufacture, the upper limit of the intrinsic viscosity is preferably less than 50 dl / g.

[0032] (2) Comonomer Amount

[0033] In the case where the propylene polymer (copolymer) of the present invention is a copolymer, the amount of the comonomer is 30% by weight or less. When the amount of the comonomer is greater than this value, the crystallinity of the copolymer decreases, the powder performance of the polymer deteriorates, and therefore the manufacturing is difficult. From this point of view, the upper limit of the amount is preferably 25% by weight or less. On the other hand, the lower limit of the amount of the comonomer is not limited, preferably 3% by weight or more, and more preferably 5% by weight or more. The amount of the comonomer is the amount of the monomer-derived unit in the copolymer. The comonomer is an α-olefin having 2 or 4 to 8 carbon atoms. Among them, from the viewpoint of reactivity, an α-olefin having 2 carbon atoms, i.e. ethylene, is preferably used as a comonomer. By copolymerizing ethylene, the intrinsic viscosity of the propylene polymer can be further increased. Therefore, in one embodiment, the propylene polymer (copolymer) of the present invention is a copolymer having an intrinsic viscosity of more than 23dl / g and an ethylene content (the content ratio of ethylene-derived units) of 3 to 30% by weight.

[0034] (3)XI

[0035] The propylene polymer (copolymer) of the present invention preferably has 40% by weight or more of xylene insolubles, more preferably 50% by weight or more of xylene insolubles, further preferably 60% by weight or more of xylene insolubles, and particularly preferably 70% by weight or more of xylene insolubles (XI). XI is a crystalline component in the propylene polymer (copolymer). The upper limit of XI is not particularly limited.

[0036] (4) Melting point

[0037] The propylene polymer (copolymer) of the present invention preferably has a melting point of 100°C or more, more preferably 120°C or more, further preferably 140°C or more, and particularly preferably 150°C or more (Tm). The melting point is the temperature at which the heat of fusion generated by melting shows a maximum value, as observed by performing a second scan using DSC. The so-called second scan means heating a melted sample (resin), cooling it to crystallize it, keeping it at room temperature for 5 minutes, heating it for the second time, and performing thermal analysis. Specifically, the sample is heated to a temperature above the melting temperature (230°C), kept at this temperature for 5 minutes, cooled to 30°C at a cooling rate of 10°C / min, kept for 5 minutes, heated to 230°C at a heating rate of 10°C / min, and thermally analyzed.

[0038] The propylene copolymer of the present invention has the following characteristics: when the type and content of the comonomer are the same, it has a higher melting point than the existing copolymer. In particular, when the propylene copolymer of the present invention is a propylene-ethylene copolymer, the Tm (°C) and the ethylene content C2 (wt%) in the copolymer preferably satisfy the formula (1).

[0039] Formula (1): Tm≥-3.4×C2+162

[0040] (5) Properties, etc.

[0041] From the viewpoint of operability, etc., the propylene polymer (copolymer) of the present invention is preferably a powder. Moreover, the powder more preferably has a powder fluidity of 3.5 or less. Powder fluidity refers to the fluidity of a powdered polymer generated in a polymerization reactor, and is an indicator of the manufacturing stability of a polymer. Specifically, powder fluidity is a value obtained by quantifying the powder fluidity when a certain load is applied to a powder placed on a substrate for a certain period of time at a certain temperature and then the load is removed, and the powder is made to flow by tilting the substrate, etc. The lower the value of the powder fluidity, the better the powder fluidity and the better the manufacturing stability. The powder fluidity of the propylene polymer (copolymer) of the present invention is preferably 3.5 or less, more preferably 3.0 or less, and further preferably 2.0 or less.

[0042] The powder flowability is measured by the following method.

[0043] A frame with an opening of 5 cm in length x 5 cm in width x 1 cm in height was placed on the metal substrate (first substrate), and 5 g of polymer was laid in the frame as a sample. The second substrate was placed on the frame so that the pressure applied to the sample became uniformly 23 g / cm 2 After the sample in the frame was kept at 70° C. for 20 minutes, the frame and the second substrate were removed, and the first substrate on which the sample was placed was tilted to evaluate the degree of collapse of the sample using the following criteria.

[0044] 1. When the inclination is above 0° and less than 30°, all collapse

[0045] 2. When the inclination is more than 30° and less than 50°, all collapse

[0046] 3. When the inclination is more than 50° and less than 70°, all collapse

[0047] 4. When the inclination is more than 70° and less than 90°, all collapse

[0048] 5. Even if it tilts more than 90°, everything will not collapse

[0049] The first substrate and the second substrate are preferably made of stainless steel from the viewpoint of heat conductivity and rust resistance during repeated use. In addition, the first substrate preferably has a surface roughness (maximum roughness Ry) of 1 μm or less in order to eliminate the influence of friction with the powder.

[0050] 2. Manufacturing method

[0051] The propylene polymer (copolymer) of the present invention is preferably produced using (A) a solid catalyst containing magnesium, titanium, halogen and an electron donor compound as essential components, (B) an organic aluminum compound, and, if necessary, (C) a catalyst containing an external electron donor compound.

[0052] (1) Solid catalyst (component (A))

[0053] Component (A) can be prepared by a known method, for example, by contacting a magnesium compound, a titanium compound and an electron donor compound. The titanium compound used in the preparation of component (A) is preferably of the general formula: Ti(OR) g X 4-g A tetravalent titanium compound represented by . In the formula, R is a hydrocarbon group, X is a halogen, and 0≤g≤4. As titanium compounds, more specific examples include titanium tetrahalides such as TiCl4, TiBr4, and TiI4; Ti(OCH3)Cl3, Ti(OC2H5)Cl3, Ti(O n -C4H9)Cl3, Ti(OC2H5)Br3, Ti(OisoC4H9)Br3, etc.; Ti(OCH3)2Cl2, Ti(OC2H5)2Cl2, Ti(O n -C4H9)2Cl2, Ti(OC2H5)2Br2 and other dihalogenated alkoxytitanium; Ti(OCH3)3Cl, Ti(OC2H5)3Cl, Ti(O n -C4H9)3Cl, Ti(OC2H5)3Br and other monohalogenated trialkoxytitanium; Ti(OCH3)4, Ti(OC2H5)4, Ti(O n -C4H9)4 etc. Tetraalkoxytitanium etc. Among them, halogen-containing titanium compounds are preferred, especially titanium tetrahalides, and titanium tetrachloride is particularly preferred.

[0054] Examples of the magnesium compound include magnesium compounds having a magnesium-carbon bond or a magnesium-hydrogen bond, such as dimethyl magnesium, diethyl magnesium, dipropyl magnesium, dibutyl magnesium, dipentyl magnesium, dihexyl magnesium, didecyl magnesium, ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride, hexyl magnesium chloride, amyl magnesium chloride, butyl ethoxy magnesium, ethylbutyl magnesium, butyl magnesium hydride, etc. These magnesium compounds may be used in the form of complex compounds of organic aluminum or the like, and may be in liquid or solid form. More preferred magnesium compounds include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, and magnesium fluoride; alkoxymagnesium halides such as methoxymagnesium chloride, ethoxymagnesium chloride, isopropoxymagnesium chloride, butoxymagnesium chloride, and octyloxymagnesium chloride; allyloxymagnesium halides such as phenoxymagnesium chloride and methylphenoxymagnesium chloride; alkoxymagnesium such as ethoxymagnesium, isopropoxymagnesium, butoxymagnesium, n-octyloxymagnesium, and 2-ethylhexyloxymagnesium; dialkoxymagnesium such as dimethoxymagnesium, diethoxymagnesium, dipropoxymagnesium, dibutoxymagnesium, ethoxymethoxymagnesium, ethoxypropoxymagnesium, and butoxyethoxymagnesium; and allyloxymagnesium such as phenoxymagnesium and dimethylphenoxymagnesium.

[0055] The electron donor compound is generally referred to as an “internal electron donor compound.” In the present invention, the internal electron donor compound is preferably a compound having an ester skeleton represented by formula (I).

[0056] [Chemical formula 1]

[0057]

[0058] In the formula, R1 is independently a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms. The hydrocarbon group may have heteroatoms such as halogen, P, S, N, O, Si, etc., and may also form a ring. The definition of R2 is the same as that of R1, but R2 and R1 do not necessarily have the same structure. Furthermore, R1 and R2 may also be connected to form a ring.

[0059] A is a divalent cross-linking group. The chain length between the cross-linking bonds is preferably 1 to 10 atoms. In the case where A has a cyclic structure, the chain length refers to the number of atoms in the shortest sequence between the oxygen atoms bonded to A. A is preferably represented by -(ZR 3 m ) n -. Z is preferably C, Si, Ge, O, N, S or P. R 3 are independently hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, and may contain the above-mentioned heteroatoms, and may be multiple R 3 The two ions are fused to form one or more rings. m is a number corresponding to the valence of Z, and n is an integer from 1 to 10. For example, R 3 It can form aromatic ring, heterocyclic ring or alicyclic ring with Z. 3 m) n - When O, S and N are contained, they are not directly bonded to the oxygen atom of formula (I).

[0060] In the present invention, it is more preferred to use a carbamate compound as the internal electron donor compound. The carbamate compound is a compound having a carbamate skeleton and is represented by formula (II).

[0061] [Chemical formula 2]

[0062]

[0063] In the formula, R4 is independently a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms. The hydrocarbon group may have a heteroatom such as halogen, P, S, N, O, Si, and two R4s may be connected to form a ring. R5 has the same definition as R4, but R4 and R5 do not necessarily have the same structure.

[0064] A is as defined above, and Z is preferably C or Si, more preferably C. In particular, compounds having the following combination are preferred.

[0065] A: A divalent aromatic group which may have a substituent. Examples of the aromatic group include phenylene and naphthylene. In addition, examples of the substituent include linear or branched alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, butyl, and pentyl.

[0066] R4, R5: a linear or branched alkyl group having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, butyl, and pentyl.

[0067] Specifically, as the compound defined in formula (II), the compounds described in the specification of US Patent Application No. 2015 / 0266981 can be used.

[0068] (2) Organic aluminum compound (component (B))

[0069] Examples of the organoaluminum compound include the following compounds.

[0070] trialkylaluminum such as triethylaluminum and tributylaluminum;

[0071] Trienyl aluminums such as triisoprenylaluminum:

[0072] Dialkylaluminum alkoxides such as diethylaluminum ethoxide and dibutylaluminum butoxide;

[0073] Alkyl aluminum sesquialkoxides such as ethyl aluminum sesquiethoxy and butyl aluminum sesquibutoxide;

[0074] Partially halogenated alkylaluminums such as ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromide, diethylaluminum chloride, dipropylaluminum chloride, and dibutylaluminum chloride;

[0075] Dialkylaluminum hydrides such as diethylaluminum hydride and dibutylaluminum hydride; partially hydrogenated alkylaluminums such as ethylaluminum dihydride and propylaluminum dihydride, and alkylaluminum dihydride;

[0076] Partially alkoxylated and halogenated alkylaluminums such as ethoxyethylaluminum chloride, butoxybutylaluminum chloride, and ethoxyethylaluminum bromide.

[0077] (3) Electron donor compound (component (C))

[0078] The electron donor compound is also referred to as an “external electron donor compound.” As the external electron donor compound, an organic silicon compound is preferred, and specific examples thereof include the following compounds.

[0079] Trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, tert-butylmethyldimethoxysilane, tert-butylmethyldiethoxysilane, tert-amylmethyldiethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, diphenyldiethoxysilane, di-o-triyldimethoxysilane, di-m-triyldimethoxysilane, di-p-triyldimethoxysilane, di-p-triyldiethoxysilane, bis-ethylphenyldimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylmethyldimethoxysilane silane, cyclohexylmethyldiethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, tert-butyltriethoxysilane, tolyltrimethoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, phenyltriethoxysilane, γ-aminopropyltriethoxysilane, chlorotriethoxysilane, ethyltriethoxysilane Isopropoxysilane, vinyl tributoxysilane, cyclohexyl trimethoxysilane, cyclohexyl triethoxysilane, 2-norbornane trimethoxysilane, 2-norbornane triethoxysilane, 2-norbornane methyl dimethoxysilane, ethyl silicate, butyl silicate, trimethylphenoxysilane, methyl triallyloxysilane, vinyl tris (β-methoxyethoxysilane), vinyl triacetoxysilane, dimethyltetraethoxydisiloxane, methyl (3,3,3-trifluoro-n-propyl) dimethoxysilane, cyclohexyl ethyl dimethoxysilane, cyclopentyl-tert-butoxy dimethoxysilane, diisobutyl dimethyl Oxysilane, isobutylisopropyldimethoxysilane, n-propyltrimethoxysilane, di-n-propyldimethoxysilane, tolyltrimethoxysilane, tert-butylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butyl-tert-butoxydimethoxysilane, isobutyltrimethoxysilane, cyclohexylisobutyldimethoxysilane, di-sec-butyldimethoxysilane, isobutylmethyldimethoxysilane, bis(decahydroisoquinolin-2-yl)dimethoxysilane, diethylaminotriethoxysilane, dicyclopentyl-bis(ethylamino)silane, tetraethoxysilane, tetramethoxysilane, isobutyltriethoxysilane.

[0080] (4) Composition ratio

[0081] The composition ratio of components (A) to (C) is not limited, but the composition ratio of components (A) and (B) is adjusted so that the Al / Ti molar ratio is preferably 10 to 1000, more preferably 30 to 600. In addition, when component (C) contains silicon, the composition ratio of components (A) and (C) is adjusted so that the Si / Al molar ratio is preferably 0.01 to 1.5, more preferably 0.05 to 1.0.

[0082] (5) Aggregation

[0083] The raw material monomer is contacted with the catalyst prepared as described above and polymerized. At this time, the catalyst can also be used for prepolymerization. The so-called prepolymerization refers to the process of forming a polymer chain in the solid catalyst component as a foothold for the subsequent main polymerization of the raw material monomer. The prepolymerization can be carried out by a known method. The prepolymerization is usually carried out below 40°C, preferably below 30°C, and more preferably below 20°C. Next, the prepolymerized catalyst (prepolymerization catalyst) is introduced into the polymerization reaction system, and the main polymerization of the raw material monomer is carried out. The polymerization can be carried out in a liquid phase, in a gas phase, or in a liquid-gas phase. The polymerization temperature is preferably 0 to 90°C, more preferably 20 to 80°C. When carried out in a liquid phase, the polymerization pressure is preferably in the range of 0.8 to 6.0 MPa, and when carried out in a gas phase, it is preferably in the range of 0.5 to 3.0 MPa. In the present invention, a chain transfer agent (such as hydrogen or ZnEt2) and other commonly used molecular weight regulators known in the field can be used in trace amounts.

[0084] In addition, a polymer having a gradient of monomer concentration or polymerization conditions can also be used. In such a polymerizer, for example, a polymerizer connected to at least two polymerization zones can be used, and monomers are polymerized by gas phase polymerization. Specifically, in the presence of a catalyst, monomers are supplied to a polymerization zone consisting of an ascending tube for polymerization, and monomers are supplied to a downcomer connected to the ascending tube for polymerization, and the monomers are circulated in the ascending tube and the downcomer while the polymer product is recovered. The method is equipped with a device for preventing the gas mixture present in the ascending tube from entering the downcomer in full or in part. In addition, a gas or liquid mixture having a composition different from that of the gas mixture present in the ascending tube is introduced into the downcomer. As the above-mentioned polymerization method, for example, the method described in the Japanese Patent Publication No. 2002-520426 can be used.

[0085] 3. Purpose

[0086] Since the propylene polymer (copolymer) of the present invention has an extremely high molecular weight, the composition containing the polymer has high melt tension and die expansion. Therefore, the propylene polymer (copolymer) of the present invention is useful in the use of extrusion molded bodies (ordinary sheets, foamed sheets, blow molded bodies, etc.) or injection molded bodies. In addition, the propylene polymer (copolymer) of the present invention also has crystallinity and infusibility, so it is also useful as an organic filler. Therefore, the propylene polymer (copolymer) of the present invention can be used alone, or it can be used as an additive or additional component and used in combination with other resins to form a composition. The method of adding can use known methods such as melt mixing or solution mixing, multi-stage polymerization polymerization mixing. Furthermore, the composition can also be used as a masterbatch and combined with other polyolefins to form a secondary composition.

[0087] In the case of obtaining a composition containing a small amount of the propylene polymer (copolymer) of the present invention by polymerizing a blend, the propylene polymer (copolymer) of the present invention can be polymerized in the prepolymerization stage. Relative to the total weight of the resin component constituting the composition, the content ratio of the propylene polymer (copolymer) of the present invention in the composition is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and further preferably 1% by weight or more. Its upper limit is preferably 20% by weight or less, more preferably 15% by weight or less, and further preferably 10% by weight or less. When the ratio is less than 0.1% by weight, it is difficult to obtain the expected formability and physical properties, and when it is greater than 20% by weight, the fluidity of the composition may be reduced.

[0088] [Example]

[0089] [Example 1]

[0090] In a 300 mL four-necked round-bottom flask purged with nitrogen, 45 mL of toluene and 10.0 g of fine spherical Mg(OC2H5)2 were introduced at 5°C. While stirring, 28.7 ml of titanium tetrachloride was added dropwise over 10 minutes, and 11.3 mmol of 5-tert-butyl-3-methyl-1,2-phenylenebis(diethylcarbamate) (hereinafter also referred to as compound a) was added. The temperature was raised to 110°C and maintained for 120 minutes. Then, stirring was stopped, the solid product was allowed to settle, and the supernatant was sucked out. Then, it was washed 4 times with toluene (75 mL) at 90°C.

[0091] To the washed solid, 50 ml of toluene was added. 21 ml of titanium tetrachloride was added thereto, and the temperature was raised to 100°C and stirred for 90 minutes. Then, stirring was stopped, the solid product was allowed to settle, and the supernatant was sucked out. Next, it was washed 6 times with heptane (75 mL) at 40°C. The washed solid was dried under reduced pressure to obtain 7.6 g of solid catalyst component (A). The solid catalyst component contained 14.3% by weight of compound a, 14.0% by weight of Mg, and 4.0% by weight of Ti.

[0092] The autoclave reactor with a stirrer having an internal volume of 20L was fully vacuum dried and replaced with nitrogen. 52.8 mg of the solid catalyst component prepared in the reactor, as well as triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (DCPMS) were added in an amount of Al / Ti molar ratio of 150 and Si / Al molar ratio of 0.2. Next, 5.6 kg of propylene was added, the temperature of the autoclave was raised to 40°C, and polymerization was carried out at 40°C for 30 minutes. After the polymerization reaction was completed, the unreacted monomers were discharged to obtain 75 g of propylene homopolymer, which was evaluated. The results are shown in Table 1.

[0093] [Examples 2 and 3]

[0094] Except for changing the Al / Ti molar ratio and Si / Al molar ratio, polymerization was carried out in the same manner as in Example 1 to obtain a propylene homopolymer, and the evaluation was performed. The results are shown in Table 1. The Al / Ti molar ratio was changed by adjusting the amount of TEAL used. Next, the same process was carried out while changing the Al / Ti molar ratio.

[0095] [Example 4]

[0096] The polymerization was carried out in the same manner as in Example 1 except that triisobutylaluminum (TIBAL) was used instead of TEAL to obtain a propylene homopolymer, which was then evaluated. The results are shown in Table 1.

[0097] [Examples 5-6]

[0098] Except for changing the polymerization temperature and Si / Al molar ratio, polymerization was carried out in the same manner as in Example 1 to obtain a real propylene homopolymer, which was then evaluated. The results are shown in Table 1.

[0099] [Example 7]

[0100] The same method as in Example 1 was used to obtain a propylene-ethylene copolymer, and the results were evaluated, except that 5 kg of propylene was added to the reactor and ethylene gas was continuously supplied during the polymerization, the ethylene partial pressure was adjusted to be constant, and the polymerization was carried out at 40° C. for 30 minutes. The results are shown in Table 1.

[0101] [Examples 8 to 12]

[0102] Except for changing the Al / Ti molar ratio and the Si / Al molar ratio and adjusting the ethylene partial pressure so that the ethylene content in the polymer is the value shown in Table 1, polymerization was carried out in the same manner as in Example 7 to obtain a propylene-ethylene copolymer, which was then evaluated. The results are shown in Table 1.

[0103] [Example 13]

[0104] The polymerization was carried out in the same manner as in Example 10 except that diisopropyldimethoxysilane (DIPMS) was used as an external electron donor compound and the ethylene partial pressure was adjusted to obtain a propylene-ethylene copolymer, which was then evaluated. The results are shown in Table 1.

[0105] [Example 14]

[0106] The polymerization was carried out in the same manner as in Example 13 except that the ethylene partial pressure was adjusted without using an external electron donor compound to obtain a propylene-ethylene copolymer, which was then evaluated. The results are shown in Table 1.

[0107] [Example 15]

[0108] The polymerization was carried out in the same manner as in Example 10 except that the polymerization temperature was 70°C and the ethylene partial pressure was adjusted to obtain a propylene-ethylene copolymer, which was then evaluated. The results are shown in Table 1.

[0109] [Example 16]

[0110] The polymerization was carried out in the same manner as in Example 10 except that 100 cc of hydrogen was introduced into the reactor as a chain transfer agent and the ethylene partial pressure was adjusted to obtain a propylene-ethylene copolymer, which was then evaluated. The results are shown in Table 1.

[0111] [Comparative Example 1]

[0112] The solid catalyst component was prepared according to the method described in Example 1 of European Patent Gazette No. 674991. The solid catalyst was obtained by supporting diisobutyl phthalate as an internal electron donor of TiCl4 (titanium tetrachloride) on MgCl2 by the method described in the above patent gazette. Except for using the solid catalyst, polymerization was carried out in the same manner as in Example 5 to obtain a propylene homopolymer, which was then evaluated. The results are shown in Table 2.

[0113] [Comparative Example 2]

[0114] The solid catalyst prepared in Comparative Example 1, TEAL and DCPMS were added to the reactor in an amount of Al / Ti molar ratio of 150 and Si / Al molar ratio of 0.15. In the same manner as in Example 16, 900 cc of hydrogen was introduced into the reactor, ethylene was continuously supplied during the polymerization, and the ethylene partial pressure was adjusted to be constant. The polymerization temperature was set to 70°C and the polymerization time was set to 60 minutes to obtain a propylene-ethylene copolymer, which was evaluated. The results are shown in Table 2.

[0115] [Comparative Example 3]

[0116] With reference to the method described in Examples of JP-A-2011-500907, a solid catalyst component was prepared as follows.

[0117] In a 500 mL four-necked round-bottom flask purged with nitrogen, 250 mL of titanium tetrachloride was introduced at 0°C. While stirring, 10.0 g of fine spherical MgCl2·1.8C2H5OH and 9.1 mmol of diethyl-2,3-(diisopropyl)succinate were added. Fine spherical MgCl2·1.8C2H5OH was produced according to the method described in Example 2 of the specification of U.S. Patent No. 4,399,054, but the rotation speed was changed from 10000 rpm to 3000 rpm.

[0118] The temperature in the flask was raised to 100°C and maintained for 120 minutes. Then, stirring was stopped, the solid product was allowed to settle, and the supernatant was sucked off. Next, the following operation was repeated twice.

[0119] 250 mL of new titanium tetrachloride was added, the mixture was reacted at 120°C for 60 minutes, and the supernatant was removed by suction. The solid was washed 6 times with anhydrous hexane (6×100 mL) at 60°C.

[0120] Except for using the above solid catalyst, polymerization was carried out under the same conditions as in Example 5 to obtain a propylene homopolymer. The results are shown in Table 2.

[0121] [Comparative Example 4]

[0122] A propylene-ethylene copolymer was obtained and evaluated in the same manner as in Example 10 except that the catalyst prepared in Comparative Example 3 was used and the ethylene partial pressure was adjusted so that the ethylene content in the polymer would be the value shown in Table 2. The results are shown in Table 2.

[0123] [Comparative Examples 5 to 8]

[0124] The polymerization was carried out in the same manner as in Example 1 except that the polymerization conditions were changed as shown in Table 2 to obtain a propylene homopolymer, which was then evaluated. The results are shown in Table 2.

[0125] [Comparative Example 9]

[0126] A 6L autoclave with a stirrer was fully vacuum dried and purged with nitrogen. 97.8 mg of titanium trichloride catalyst (manufactured by Tosoh Finechem) and diethylaluminum chloride (DEAC) as an organic aluminum compound were added in an amount of Al / Ti molar ratio of 13. Next, 1.5 kg of propylene was added, the temperature of the autoclave was raised to 60°C, and polymerization was carried out at 60°C for 30 minutes. After the polymerization reaction was completed, the unreacted monomers were removed, 250 ml of isobutanol was added, and decalcification was carried out at 80°C for 1 hour. Then, the solid components were allowed to settle and the supernatant was sucked out. Then, it was washed twice with heptane (300 mL) at 80°C to obtain 73 g of propylene homopolymer, which was evaluated. The results are shown in Table 2.

[0127] [Comparative Example 10]

[0128] The polymerization was carried out in the same manner as in Comparative Example 9 except that the polymerization temperature was changed to 40°C to obtain a propylene homopolymer, which was then evaluated. The results are shown in Table 2.

[0129] [Table 1]

[0130]

[0131]

[0132]

[0133] [Example 17]

[0134] 1) Polypropylene resin composition

[0135] Using the solid catalyst containing compound a prepared in Example 1, polymerization was carried out according to the following method.

[0136] 〔Front stage polymerization〕

[0137] The reactor of the autoclave with a stirrer having an internal volume of 20L was fully vacuum dried and replaced with nitrogen. 59.3 mg of the solid catalyst component containing the prepared compound a, as well as TEAL and DCPMS were added in an amount of Al / Ti molar ratio of 150 and Si / Al molar ratio of 1.0. Next, 5.6 kg of liquefied propylene was added to the reactor, and ethylene gas was continuously supplied during the polymerization, and the ethylene partial pressure was adjusted to be constant, and the polymerization was performed at 40°C for 10 minutes. The propylene-ethylene copolymer of the present invention was obtained by adjusting the polymerization pressure. Then, the unreacted monomers were removed and the reaction vessel was fully replaced with nitrogen.

[0138] (Post-polymerization)

[0139] Next, TEAL and DCPMS were added to the reactor in an amount of Al / Ti molar ratio of 400 and Si / Al molar ratio of 0.05. 5.6 kg of liquefied propylene and hydrogen were added so that the hydrogen concentration in the liquid propylene was 0.7 mol%, the temperature of the autoclave was raised to 70°C, and polymerization (propylene polymerization) was carried out for 180 minutes. After the polymerization reaction was completed, the unreacted monomers were removed to obtain 4.6 kg of a powdered composition. The composition is a composition obtained by mixing the propylene-ethylene copolymer of the present invention and polypropylene polymerization. The physical properties of the composition are shown in Table 3. However, the intrinsic viscosity, the content ratio of ethylene-derived units, and the melting point of the propylene-ethylene copolymer of the present invention are the analysis results of the polymer obtained only after the front-stage polymerization under the same conditions. In addition, in the composition, the ratio of the propylene-ethylene copolymer of the present invention is calculated by the activity ratio with the front-stage polymerization.

[0140] To the composition obtained above, 0.2phr of B225 manufactured by BASF as an antioxidant and 0.1phr of calcium stearate manufactured by Tamnan Chemical Industry Co., Ltd. as a neutralizer were added, and stirred for 1 minute using a Henschel mixer to obtain a mixture. Next, the mixture was melt-kneaded using an extruder (manufactured by Technovel Co., Ltd., screw diameter 15mm, co-rotating twin-screw extruder) with a screw temperature set to 230°C. Next, the molten mixture was discharged from the extruder, cooled to form a strand, and the strand was cut to obtain a granular polypropylene resin composition.

[0141] 2) Formation of foam

[0142] 4 phr of CELLMIC MB3064 manufactured by Sankyo Chemical Industry Co., Ltd. was added as a foaming agent to the polypropylene resin composition obtained above, and dry-blended to obtain a foamable composition. Next, the foamable composition was used to form foam strands under the following conditions, and the obtained foam was evaluated.

[0143] Extruder: Single-screw extruder TP-15 manufactured by Thermo Plastics Industries, Ltd.

[0144] Die shape: wire drawing die

[0145] Mold size: 2mmφ

[0146] Extrusion rate: 500g / h

[0147] Screw shape: Full-thread screw

[0148] Screw speed: 40rpm

[0149] Cylinder set temperature: 210℃

[0150] Mold temperature setting: 180℃

[0151] Similarly, 6 phr of CELLMIC MB3064 manufactured by Sankyo Chemical Industry Co., Ltd. was added as a foaming agent to the polypropylene resin composition obtained in 1), and dry-blended to obtain a foamable composition. A foam was obtained using the foamable composition and evaluated as described above.

[0152] Similarly, the polypropylene resin composition obtained in 1) was heat-pressed at 230°C to obtain a non-foamed sheet (thickness 500 μm). This sheet was cut to prepare test pieces, and the rigidity was measured. The results are shown in Table 3.

[0153] [Table 3]

[0154]

[0155] The evaluation was carried out as follows.

[0156] [Content ratio of ethylene-derived units]

[0157] The propylene polymer (copolymer) sample was heat-pressed at 230°C to prepare a sheet with a thickness of 0.4 mm. The IR absorption spectrum of the sample to the air background was collected by Fourier transform infrared spectroscopy (FT-IR). The 760 cm-690 cm-1 absorption spectrum was corrected by using the thickness of the sheet. -1 The peak area of ​​ethylene derivative units was used to determine the content ratio (weight %) of ethylene derived units in the propylene polymer (copolymer). The data collection parameters were as follows.

[0158] Apodization: Cosine

[0159] Resolution: 2cm -1

[0160] [Polymer XI]

[0161] While stirring 0.1-0.5 g of the polymer, dissolve it in 250 mL of xylene at 135°C. After 30 minutes, cool the solution to 25°C while stirring, and then let it stand for 30 minutes. Filter the precipitate with filter paper, evaporate the solution in a nitrogen stream, and vacuum dry it at 80°C until the residue reaches a constant weight. In this way, calculate the weight % of the polymer soluble in xylene at 25°C. The amount of xylene insolubles (weight % of insoluble polymer in xylene at 25°C, XI) can be calculated by 100-"weight % of soluble polymer" and can be considered as the amount of crystalline components in the polymer.

[0162] [Intrinsic viscosity of polymer]

[0163] A sample of a propylene polymer (copolymer) was dissolved in tetralin at 135° C. to obtain a solution having a concentration of 0.01 wt %. The intrinsic viscosity of this solution was measured using a capillary automatic kinematic viscometer (SS-780-H1, manufactured by Shibayama Scientific Instruments Co., Ltd.).

[0164] [Powder fluidity]

[0165] A metal frame with an opening of 5 cm in length, 5 cm in width, and 1 cm in height was placed on the metal plate, and 5 g of polymer was laid in the metal frame as a sample. A 0.92 g metal cover was placed in the metal frame so that the pressure applied to the sample became uniformly 23 g / cm 2 After the sample in the metal frame is kept at 70°C for 20 minutes, the metal frame and the metal cover are removed, and the sample is placed on a metal plate and tilted. Five-level evaluation is performed no more than 4 times, and the average value is calculated.

[0166] 1. When the inclination is above 0° and less than 30°, all collapse

[0167] 2. When the inclination is more than 30° and less than 50°, all collapse

[0168] 3. When the inclination is more than 50° and less than 70°, all collapse

[0169] 4. When the inclination is more than 70° and less than 90°, all collapse

[0170] 5. Even if it tilts more than 90°, everything will not collapse

[0171] The metal plate, metal frame, and metal cover were made of SUS304 stainless steel, and the surface was polished (polished) with #400 to obtain a surface roughness (maximum roughness Ry) of 0.2 μm.

[0172] [Melting point of polymer]

[0173] The melting point of the polymer is measured by performing the second scan defined as above using a diamond DSC manufactured by Perkin Elmer.

[0174] [MFR]

[0175] The measurement was performed in accordance with JIS K7210-1 under the conditions of a temperature of 230° C. and a load of 2.16 kg.

[0176] [Melt tension]

[0177] The resin composition was melted at a temperature of 200° C. using a capillary rheometer (capillary FIG. 1D manufactured by Toyo Seiki Seisaku-sho, Ltd.) equipped with a cylindrical orifice having a length of 8.0 mm and a diameter of 2.095 mm and a flat upper surface. The molten resin composition was discharged from the orifice at a resin extrusion speed of 15 mm / min to form a strand. The strand was pulled at a pulling speed of 6.5 m / min using a rotating pulling device, and the melt tension (melt tension, unit is g weight) was measured.

[0178] [Appearance of foam]

[0179] The appearance of the foamed strands expanded to 3.0 times or more and 3.4 times or less was evaluated according to the following criteria.

[0180] A: The surface is smooth and the wire is straight

[0181] B: The surface is slightly concave or convex.

[0182] C: The surface is uneven and the wire material is undulating

[0183] [Independent bubbles]

[0184] The foamed strands expanded to 3.0 to 3.4 times were cut into 4 cm lengths with a razor, one side of which was immersed in a pigment ethanol solution for 30 seconds, and the closed cell properties were evaluated using the distance from the cut surface to the inside where the ethanol was most permeated (maximum coloring distance).

[0185] A: The maximum coloring distance is less than 2mm

[0186] B: The maximum coloring distance is greater than 2mm and less than 20mm

[0187] C: Maximum coloring distance is greater than 20mm

[0188] [rigidity]

[0189] The non-foamed sheet was punched out to have a length of 2.75 inches and a width of 1.5 inches, and five test pieces were prepared.

[0190] The rigidity of each test piece was measured at room temperature of 23° C. in accordance with JIS P8125 using a V-5 rigidity tester (model 150-B) manufactured by Taber Instruments Corporation. The measurement conditions at this time were as follows.

[0191] Measuring range: 50-500

[0192] Range Weight: 500 units

[0193] Warp angle: 15°

[0194] Measuring span: 5cm

[0195] Zoom ratio: 5 times

[0196] Keep time 1 minute

[0197] Measurement temperature: 23°C

[0198] For each test piece, the values ​​of the warping angles of 15° on the left and right were read, and the values ​​were averaged to determine the rigidity. Then, the rigidity of the non-foamed sheet was determined by the following formula.

[0199] E=9.83×T su / t 3

[0200] (E: sheet rigidity [MPa], T su : average value of rigidity [gf·cm], t: thickness of test piece [mm])

[0201] The larger the stiffness value, the higher the stiffness.

[0202] It is obvious that, when the content ratio of the ethylene-derived unit in the polymer is the same, the propylene-ethylene copolymer in the example having an intrinsic viscosity of more than 20 dl / g has better powder flowability than the propylene-ethylene copolymer in the comparative example having an intrinsic viscosity of 20 dl / g or less. In addition, it is obvious that the non-foamed sheet and foam obtained from the composition containing the propylene polymer (copolymer) of the present invention also have excellent properties.

Claims

1. A copolymer of propylene and 30% by weight or less of ethylene, wherein: The intrinsic viscosity measured in tetralin solvent at 135°C is 23 dl / g or more, The melting point Tm of the copolymer in degrees Celsius determined by DSC at a heating rate of 10°C / min and the ethylene content C2 in the copolymer in weight percent satisfy the following formula (1): Tm≥-3.4×C2+162...(1) The melting point Tm is obtained by using DSC at a heating rate of 10°C / min, and is the peak temperature of the melting curve observed in the second scan, and is the temperature at which the heat of melting generated by melting shows a maximum value. The xylene insoluble matter XI at 25°C is 70% by weight or more, The melting point Tm is 140° C. or higher.

2. The copolymer according to claim 1, wherein The intrinsic viscosity is 50 dl / g or less, and the ethylene content is 3 to 30% by weight.

3. A method for producing a copolymer, which is the method for producing a copolymer according to claim 1 or 2, wherein: It includes the following steps: Using (A) a solid catalyst containing magnesium, titanium, halogen and an electron donor compound as essential components, (B) an organoaluminum compound, and According to the required (C) catalyst containing an external electron donor compound, the corresponding monomer is polymerized to prepare, The electron donor compound is a compound having an ester skeleton represented by formula (I), [Chemical formula 1] In the formula, R1 and R2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms, and the hydrocarbon group may contain halogen, P, S, N, O, Si, or may form a ring; R1 and R2 may be connected to form a ring; A is a divalent cross-linking group, the chain length between the cross-linking bonds is 1 to 10 atoms, represented by -(ZR 3 m ) n -, Z is C, Si, Ge, O, N, S or P, R 3 Each independently represents hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, and may contain halogen, P, S, N, O, Si, and may be multiple R 3 fused to form one or more rings, m is a number corresponding to the valence of Z, n is an integer from 1 to 10, in -(ZR 3 m ) n - When O, S and N are contained, they are not directly bonded to the oxygen atom of formula (I).

4. The method for producing a copolymer according to claim 3, wherein The electron donor compound is a compound having a carbamate skeleton, represented by formula (II): [Chemical formula 2] In the formula, R4 and R5 are each independently a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms, the hydrocarbon group may contain halogen, P, S, N, O, Si, and two R4 may be connected to form a ring; A is as defined above, and Z is C or Si.

5. The method for producing a copolymer according to claim 4, wherein In the formula (II), A is a divalent aromatic group which may be substituted, R4 is a linear or branched alkyl group having 1 to 5 carbon atoms, and R5 is a linear or branched alkyl group having 1 to 5 carbon atoms.

6. A polypropylene resin composition, comprising the copolymer according to claim 1 or 2, wherein: The content ratio of the copolymer is 0.1 to 20% by weight relative to the total weight of the resin components constituting the composition.

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