JP2005097548A - Polypropylene resin and application of the resin to sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoforming polypropylene resin easily formable by sheet forming and thermoforming and having high rigidity, and provide a resin composition, a sheet made of the resin and a thermoformed product. <P>SOLUTION: The propylene polymer is composed of propylene and ethylene or a 4-20C α-olefin and has [1] the content of the structural unit derived from ethylene or the 4-20C α-olefin of 0.1-2.0 mol%, [2] the melt flow rate (230°C, 2.16 kg load) of 0.1-5.0 g/10 min, [3] the Mw/Mn ratio of 5.0-20 measured by a GPC method, and [4] the stereoregularity index [M<SB>5</SB>] of 0.960-0.990 calculated from Pmmmm and Pw absorption intensity values of<SP>13</SP>C-NMR spectrum. The sheet made of a resin composition containing the polymer has excellent rigidity, heat-resistance and thermoforming property and is suitable as a material for thermoformed products. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a propylene-based polymer, a resin composition containing the polymer, and a sheet and a thermoformed body comprising the same.

  Polypropylene sheets have characteristics such as high rigidity, high heat resistance, and recyclability, and therefore are widely used as various packaging materials such as food containers, industrial materials, and pharmaceuticals.

  In recent years, various studies have been made on sheet products to reduce the thickness, reduce the amount of filler, or expand the foam in order to protect the environment, reduce weight, and reduce costs. The current situation is.

  Known methods for improving the rigidity of sheet products include a method using a polypropylene resin having an increased isotactic mesopentad fraction and a method using a polypropylene resin composition to which a nucleating agent is added. (For example, described in JP-A-7-33920 and JP-A-2001-089122).

However, since the above-mentioned method has a secondary high melting point, as a result, the sheet preheating time in thermoforming becomes long, which adversely affects productivity.
JP 7-33920 A JP 2001-89122 A

  The problem to be solved by the present invention is to provide a polypropylene resin having excellent rigidity and heat resistance and also having excellent thermoformability, and a sheet and a thermoformed body made of the resin.

  As a result of intensive studies on the polypropylene resin to solve the above problems, the present inventors have found that the comonomer content in a specific range, the melt flow rate in a specific range, a specific molecular weight distribution, and a specific stereoregularity. A sheet comprising a combined propylene polymer, and a polypropylene resin composition containing a specific amount of the propylene polymer and polyethylene, have extremely excellent rigidity and heat resistance, and have good thermoformability, The thermoformed body obtained from the sheet has been found to be able to dramatically improve the rigidity and heat resistance compared to the conventional one, and the present invention has been completed.

  That is, the present invention includes the following propylene-based polymers (A), (A ′) and (A ″), a resin composition (B) containing the same, [in the following description, (A), (A ′) , (A ″), and (B) may be collectively referred to as polypropylene resin. And sheets and thermoformed bodies (C1) and (C2) comprising these.

(A) A propylene-based copolymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms, which simultaneously satisfies the following requirements [1] to [4].
[1] The content of the structural unit derived from ethylene or an α-olefin having 4 to 20 carbon atoms is in the range of 0.1 to 2.0 mol%,
[2] Its melt flow rate (230 ° C, 2.16kg load) is 0.1-5.0g / 10min,
[3] Mw / Mn measured by GPC method is 5.0-20,
[4] The value of the stereoregularity index [M ₅ ] determined by the following formula (Eq-1) from the absorption intensity of Pmmmm and Pw in the ¹³ C-NMR spectrum is in the range of 0.960 to 0.990,

(In the formula, [Pmmmm] indicates the absorption intensity derived from the methyl group of the third unit at the site where 5 units of the propylene unit are isotactically bonded, and [Pw] is the absorption intensity derived from the methyl group of the propylene unit. Is shown.)

(A ′) The propylene polymer (A), which has a melting point measured by DSC of 150.0 to 163.0 ° C. and a melt tension of 230 ° C. of 80 to 180 mN. [In the following description, these two requirements may be referred to as requirement [5] and requirement [6], respectively. ]
(A '') The propylene-based polymer (A '), which is a propylene-based polymer having a tensile modulus of elasticity of 1500 to 1900 MPa measured according to ASTM-D-882 and having a thickness of 0.6 mm. Coalescence. [In the following description, this requirement may be referred to as requirement [7]. ]
(B) the propylene polymer (A), (A ′) or (A ″) 70 to 98% by weight, and a polymer (Q) 2 to 30% by weight different from the propylene polymer; A polypropylene resin composition comprising:
(C1) A polypropylene sheet comprising the polypropylene resin (A), (A ′) or (A ″), or a molded article obtained by thermoforming the sheet.
(C2) A polypropylene sheet comprising the polypropylene resin composition (B), or a molded article obtained by thermoforming the sheet.

  The sheet made of the propylene polymer or resin composition of the present invention is excellent in rigidity, heat resistance and thermoformability, and can be suitably used as a material for thermoformed products.

  The polypropylene resin of the present invention is a propylene polymer (A) or a resin composition (B) containing the propylene polymer (A).

  The propylene-based polymer (A) of the present invention is a polymer containing propylene as a structural unit, and is a copolymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms. Here, examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1 -Tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like. Among these, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable. The content of structural units derived from these α-olefins is 0.1 to 2.0 mol%, preferably 0.2 to 0.8 mol% in the polypropylene resin.

  The melt flow rate (MFR) of the propylene polymer of the present invention is in the range of 0.1 to 5.0 g / 10 minutes, preferably 0.3 to 1.0 g / 10 minutes. Since the MFR is within this range, the extrudability in sheet forming is excellent.

  Next, the Mw / Mn measured by the GPC method of the propylene polymer (A) of the present invention is 5.0 to 20, preferably 7.0 to 14. Mw / Mn is an index indicating the molecular weight distribution, and if this value is within the above range, the polymer has a relatively wide molecular weight distribution, so that the melt tension is high and the drawdown property in thermoforming is low. It becomes good.

The value of the stereoregularity index [M ₅ ] determined by the following formula (Eq-1) from the Pmmmm and Pw absorption intensities in the ¹³ C-NMR spectrum of the propylene polymer (A) of the present invention is 0.960 to 0.990. Preferably it is 0.970-0.990. By setting it within this range, a highly rigid and heat-resistant sheet and a thermoformed article can be obtained.

  In the above formula (Eq-1), [Pmmmm] represents the absorption intensity derived from the methyl group of the third unit at the site where 5 units of the propylene unit are isotactically bonded, and [Pw] represents the propylene unit. Absorption intensity derived from a methyl group is shown.

  In a preferred embodiment of the propylene polymer (A) of the present invention, the melting point (Tm) measured by DSC is 150 to 163 ° C, preferably 157 to 162 ° C (requirement [5]). Conventionally used polypropylene sheets have a Tm of about 163 ° C., so the sheet preheating time in thermoforming does not become longer than before.

  In another preferred embodiment of the propylene polymer (A) of the present invention, the melt tension at 230 ° C. is 80 to 180 mN, preferably 90 to 180 mN (requirement [6]). By setting the melt tension within this range, the drawdown of the sheet in thermoforming is reduced and the deep drawability is improved.

  In the propylene polymer (A) of the present invention, in addition to the requirements [5] and [6] regarding the melting point and the melt tension, measurement is performed in accordance with ASTM-D-882 (tensile speed: 10 mm / min). In addition, it is preferable that the tensile elastic modulus of the 0.6 mm thick sheet has a characteristic of 1500 to 1900 MPa, preferably 1600 to 1900 MPa (requirement [7]). By setting it in this range, a highly rigid and highly heat-resistant sheet and a thermoformed article can be efficiently obtained.

The propylene-based polymer satisfying the ethylene or α-olefin content of 4 to 20 carbon atoms, MFR, Mw / Mn, [M ₅ ], Tm, etc. is a supported titanium catalyst, for example, a magnesium supported titanium catalyst. And copolymerization of propylene and the above-mentioned monomer is carried out by multistage polymerization of two or more stages.

  Examples of the magnesium-supported titanium-based catalyst include a catalyst containing a solid titanium catalyst component containing magnesium, titanium, halogen and an electron donor, an organometallic compound and an electron donor.

The stereoregularity of the propylene-based polymer is greatly influenced by the type of electron donor, and as an electron donor capable of obtaining high stereoregularity, an organosilicon compound is desirable, and the monomer insertion direction due to steric hindrance during polymerization is determined. As a result of regulation, the stereoregularity is improved.
The organosilicon compound used in the present invention is represented by the following general formula (I).

R ^a _n Si (OR ^b ) _4-n ---------- (I)
In the general formula (I), n is 1, 2 or 3, and when n is 1, ^Ra is a secondary or tertiary hydrocarbon group, and when n is 2 or 3, at least 1 of ^Ra One is a secondary or tertiary hydrocarbon group, R ^a may be the same or different, R ^b is a hydrocarbon group having 1 to 4 carbon atoms, and 4-n is 2 or When it is 3, R ^b may be the same or different.

  As the organosilicon compound represented by the general formula (I), when n is 1, for example, cyclopentyltrimethoxysilane, 2-methylcyclopentyltrimethoxysilane, 2,3-dimethylcyclopentyltrimethoxysilane, cyclopentyltrimethyl Examples include trialkoxysilanes such as ethoxysilane, iso-butyltriethoxysilane, t-butyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, 2-norbornanetrimethoxysilane, and 2-norbornanetriethoxysilane. it can.

  In the general formula (I), when n is 2, for example, dicyclopentyldiethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-amylmethyldiethoxysilane, dicyclohexyldimethoxysilane, cyclohexyl Examples thereof include dialkoxysilanes such as methyldimethoxysilane, cyclohexylmethyldiethoxysilane, and 2-norbornanemethyldimethoxysilane.

  In the general formula (I), when n is 3, tricyclopentylmethoxysilane, tricyclopentylethoxysilane, dicyclopentylmethylmethoxysilane, dicyclopentylethylmethoxysilane, dicyclopentylmethylethoxysilane, cyclopentyldimethylmethoxysilane, cyclopentyldiethyl And monoalkoxysilanes such as methoxysilane, cyclopentyldimethylethoxysilane, and trimethylmethoxysilane.

  Among these, dimethoxysilanes are preferable, and specifically, dicyclopentyldimethoxysilane, di-t-butyldimethoxysilane, di (2-methylcyclopentyl) dimethoxysilane, di (3-methylcyclopentyl) dimethoxysilane, di-t -Amyldimethoxysilane is preferred.

  Multi-stage polymerization is a polymerization method that broadens the molecular weight distribution by, for example, producing relatively high molecular weight polypropylene in the former stage polymerization and producing relatively low molecular weight polypropylene in the latter stage polymerization.

Specifically, in the case of two-stage polymerization, the polypropylene contained in the polypropylene finally obtained in the first stage has an intrinsic viscosity [η _1st ] of 3.0 to 4.5 dl / g, preferably 3.5 to 4.5 dl / g. In the polypropylene which is produced in an amount of 10 to 60% by weight, and then finally, in the second stage, polypropylene having an intrinsic viscosity [η _2nd ] of 0.1 to 5 dl / g, preferably 0.3 to 3 dl / g is finally obtained. Is produced in an amount of 90 to 40% by weight. At this time, the copolymerization is carried out at all stages or at any stage.

Thus, when the intrinsic viscosity [η _1st ] of the polypropylene polymerized in the previous stage is within the above range, the generation amount of fish eye (propylene lump etc.) is suppressed, and a sheet or thermoformed article having a good appearance is obtained. be able to.

  In the present invention, the above propylene polymers (A) to (A ″) may be combined with another polymer (Q) different from the polymer. That is, the propylene polymers (A) to (A '') described above may be used alone or in the form of a resin composition blended with the polymer (Q) [hereinafter, such a resin composition is used. It is called a polypropylene resin composition (B). ] Can also be used.

  The polypropylene resin composition (B) of the present invention is a resin composition of the above-described propylene polymers (A) to (A ″) and the polymer (Q), and the constituent ratio thereof is the polypropylene system. The polymer is 70 to 98% by weight, preferably 80 to 90% by weight, and the polymer (Q) is 2 to 30% by weight, preferably 10 to 20% by weight. A resin composition in this mixing ratio range is desirable because, as a result of the further improvement in drawability in thermoformability, the width of the sheet can be expanded and the productivity is improved and the impact resistance is also improved.

  Examples of the polymer (Q) include polyethylene; poly α-olefins such as polybutene-1, polyisobutene, polypentene-1 and polymethylpentene-1, ethylene / propylene copolymers having a propylene content of less than 75% by weight, ethylene Ethylene or α-olefin / α-olefin copolymer such as butene-1 copolymer, propylene / butene-1 copolymer with a propylene content of less than 75% by weight; ethylene / propylene with a propylene content of less than 75% by weight Ethylene such as propylene / 5-ethylidene-2-norbornene copolymer or α-olefin / α-olefin / diene monomer copolymer; vinyl monomer / diene monomer such as styrene / butadiene random copolymer Random copolymers; vinyl monomers, diene monomers, vinyl monomer blocks such as styrene / butadiene / styrene block copolymers Polymer; Hydrogenation (Styrene / Butadiene Random Copolymer), etc. (Vinyl Monomer / Diene Monomer Random Copolymer); Hydrogenation (Styrene / Butadiene / Styrene Block Copolymer), etc. (Vinyl monomer / diene monomer / vinyl monomer block copolymer).

  Of these polymers (Q), polyethylene is preferred. The usable polyethylene has an MFR (190 ° C., under a load of 2.16 kg) of 0.1 to 10 g / 10 min, preferably 0.1 to 5 g / 10 min. Specifically, a low-density polyethylene having a long chain branch produced by a high-pressure method, a low-density polyethylene having a linear molecular structure, a high-density polyethylene, or a mixture of two or more of them may be preferably used. it can.

  When a resin or rubber other than polyethylene is used as the polymer (Q), the amount added varies depending on the type of resin to be added or the type of rubber, as long as the object of the present invention is not impaired as described above. Usually, it is about 10% by weight or less in the propylene-based polymers (A) to (A ″).

  Further, when the sheets (C1) and (C2) are formed using the polypropylene resin of the present invention as a raw material, a filler may be added within a range not departing from the object of the present invention. Examples of fillers include talc, calcium carbonate, clay, mica, glass fiber, glass flake, glass beads, calcium silicate, silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, hydroxylation Aluminum, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, montmorillonite, bentonite, graphite, aluminum powder, molybdenum sulfide, boron fiber, silicon carbide fiber, polyester fiber and polyamide fiber Etc.

  The amount of filler added varies depending on the type of filler to be added, and may be in a range that does not impair the object of the present invention as described above, but is usually about 30% by weight or less in the propylene-based polymer or resin composition. It is.

  Further, when the sheet (C1) or (C2) is formed using the propylene polymer or resin composition of the present invention as a raw material, an antioxidant, an ultraviolet absorber, a metal soap, You may add additives, such as stabilizers, such as a hydrochloric acid absorber, a lubricant, a flame retardant, an antistatic agent, and a foaming agent.

  The amount of additive varies depending on the type of additive to be added, and may be in a range that does not impair the object of the present invention as described above, but is usually a propylene polymer (A) to (A '') or resin. It is about 3% by weight or less in the composition (B).

  A sheet made of a propylene-based polymer or resin composition having such physical properties or composition has high rigidity and heat resistance and good thermoformability. Usually, the propylene polymer or resin composition supplied to an extruder is extruded from a T-die attached to the tip of the extruder at a resin temperature of 170 to 280 ° C, preferably 200 to 250 ° C, and 30 ° C or higher. It is preferably taken off while being cooled by a cooling roll adjusted to a temperature of 60 ° C. to 90 ° C. It is desirable that the pulling speed is 0.2 to 10 m / min, and that the thickness of the sheet passed through the cooling roll is 0.1 to 10 mm. The present invention also includes a propylene sheet made from a mixture of the propylene polymer and the polypropylene resin composition.

  The polypropylene sheet includes unstretched sheets, multilayer sheets, uniaxial and biaxially stretched sheets. Examples of the stretching method include a sequential biaxial stretching method using a tenter method and a simultaneous biaxial stretching method using a tubular method.

  In the case where the polypropylene sheet is a multilayer sheet, the layer structure is not limited, and if at least one layer made of the propylene-based polymer or resin composition of the present invention is included, the thermoformability will be good. The multilayer sheet is, for example, one using the polypropylene resin or resin composition of the present invention for the core layer, a random PP having a low melting point for the skin layer, and improving heat sealability, and further, for the innermost layer. Examples thereof include a high-performance sheet using a gas barrier resin such as ethylene / vinyl alcohol resin.

  The polypropylene sheet has good productivity because it has a small drawdown and a short heating time in thermoforming such as vacuum forming and pressure forming. The obtained thermoformed product can be used for a wide range of applications as various packaging materials such as food containers, industrial materials, and pharmaceuticals.

  EXAMPLES Next, although this invention is demonstrated in detail based on an Example, this invention is not limited to those Examples. The measuring method of the physical property in an Example is as follows.

1) Melt flow rate (MFR)
According to ASTM-D1238, measurement was performed at 230 ° C. under a load of 2.16 kg.
2) Melt Tension Using a Capillograph 1C manufactured by Toyo Seiki Co., Ltd., the tension applied when the strand extruded at 230 ° C. and 15 mm / min was drawn at 15 m / min was measured as the melt tension.
Capillary shape: L = 8mm, D = 2.095mm
3) Mw and Mn
The measurement was performed by the GPC method under the following conditions.
Equipment: 150Cvtype manufactured by Waters, sample concentration: 7.5mg / 4ml, column: Shodex AD-806ms manufactured by Showa Denko KK, measurement temperature: 135 ° C, solvent: o-dichlorobenzene, polystyrene conversion

4) Intrinsic viscosity [η]
Measurements were made in a 135 ° C. tetralin solvent.
5) Isotactic pentad fraction ([M ₅ ])
^It was determined by the above formula (Eq-1) from the absorption intensity of Pmmmm and Pw in the ¹³ C-NMR spectrum. However, peak assignment was performed according to Polymer, 1993, Vol34, No14, 3129-3131.
6) Melting point
Using DSC, the melting heat peak at a heating rate of 10 ° C./min was taken as the melting point.

7) Tensile modulus
Measurement was performed under the following conditions in accordance with ASTM-D-882.
Specimen shape: Type 1 (thickness 0.6 mm), chuck interval: 100 mm, tensile speed: 10 mm / min
8) DuPont impact strength sheet thickness: 0.6mm, falling weight tip diameter: 1/2 inch φ, bearing diameter: 1/2 inch φ, temperature: 23 ° C
9) Deflection temperature under load
Measured according to ASTM-D-648. Load: 0.45MPa

10) Thermoformability (stretching time and 30mm stretching time )
The sheet formed by the sheet forming machine changes as shown in FIG. 1 in the preheating process of thermoforming. First, the sheet with both ends fixed is thermally expanded by the heating of the upper and lower heaters, and irregular wrinkles are formed (process 1). In addition, it sags once due to softening and thermal expansion (process 2), and when the entire sheet reaches the vicinity of the melting point, it shrinks due to residual stress and instantly stretches back (process 3). When heated further, the sheet melts completely and draws down due to its own weight (process 4). Usually, during steps 3 to 4, the sheet is fed onto a mold and shaped by vacuum suction or the like. Here, as the sheet 3 has a shorter turn-back time and is less likely to be drawn down, the thermoformability becomes better.
The time until this rebound and the time until 30 mm after the rebound were measured using a vacuum / pressure air forming machine manufactured by Asano Seisakusho under the following conditions.
Upper and lower heater temperature: 350 ° C, distance between upper and lower heaters: 200 mm, sheet size: 350 x 350 mm, sheet thickness: 0.6 mm

  A propylene polymer is a supported titanium catalyst (high stereoregularity catalyst) in which the electron donor is dicyclopentyldimethoxysilane. Random copolymerization with an ethylene constituent content of 0.6 mol% is obtained by two-stage polymerization. The molecular weight distribution was broadened by adjusting the high molecular weight polymer having an intrinsic viscosity [η] of 4.3 dl / g to 52% by weight and the low molecular weight material having an intrinsic viscosity [η] of 2.1 dl / g to 48% by weight. Using propylene / ethylene copolymer, 100% by weight of the copolymer, tetrakis [methylene-3 (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, a phenolic antioxidant 0.1 parts by weight (manufactured by Ciba Specialty Chemicals), 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite (Asahi Denka Kogyo Co., Ltd.), a phosphorus-based antioxidant ) 0.1 parts by weight, lactone-based antioxidant 0.02 part by weight of a reaction product of 3-hydroxy-5.7-t-butyl-furan-2-one and o-xylene (manufactured by Ciba Specialty Chemicals Co., Ltd.), calcium stearate (Nippon Yushi) as a neutralizing agent 0.1 parts by weight of Co., Ltd. was blended, and melt kneaded at a resin temperature of 230 ° C. using a single screw extruder, and granulated into pellets. Table 1 shows the measured physical properties of the obtained pellets.

  The pellet obtained above is supplied to a sheet molding machine, adjusted to a resin temperature of 270 ° C, extruded from a T die, and a cooling roll maintained at a temperature of 80 ° C is used to take a sheet having a thickness of 0.6 mm. Molded at 1.2 m / min. The mechanical properties and thermoformability of the obtained sheet were evaluated, and the results are shown in Table 1.

  Instead of the propylene-based polymer used in Example 1, a supported titanium-based catalyst in which the electron donor is dicyclopentyldimethoxysilane is used, and random copolymerization with an ethylene structural unit content of 0.4 mol% is two-stage polymerization To adjust the molecular weight distribution to 51 wt% for high molecular weight polymers with an intrinsic viscosity [η] of 4.3 dl / g and 49 wt% for low molecular weight materials with an intrinsic viscosity [η] of 2.2 dl / g to broaden the molecular weight distribution The same procedure as in Example 1 was conducted except that a propylene / ethylene copolymer was used. The results are also shown in Table 1.

  Instead of the propylene-based polymer used in Example 1, a supported titanium-based catalyst in which the electron donor is dicyclopentyldimethoxysilane is used, and random copolymerization with an ethylene structural unit content of 0.8 mol% is performed in two stages. Adjusts the molecular weight distribution so that the high molecular weight polymer with an intrinsic viscosity [η] of 4.2 dl / g is adjusted to 51 wt% and the low molecular weight polymer with an intrinsic viscosity [η] of 2.2 dl / g is adjusted to 49 wt%. The same procedure as in Example 1 was conducted except that a propylene / ethylene copolymer was used. The results are also shown in Table 1.

  Instead of the propylene polymer used in Example 1, 80% by weight of the same propylene polymer as in Example 1, 190 ° C., MFR measured under a load of 2.16 kg is 0.35 g / 10 min. Consists of 15% by weight of polyethylene (Mirason 102 manufactured by Mitsui Chemicals) and 5% by weight of high-density polyethylene (Hi-Zex 5202B manufactured by Mitsui Chemicals) with an MFR measured under the same conditions of 0.32 g / 10 min. This was carried out in the same manner as in Example 1 except that the resin composition used was used. The results are also shown in Table 1.

  Instead of the propylene polymer used in Example 1, a resin composition composed of 85% by weight of the same propylene polymer as in Example 1 and 15% by weight of the same high-density polyethylene as in Example 4 was used. Was carried out in the same manner as in Example 1. The results are also shown in Table 1.

[Comparative Example 1]
Instead of the propylene polymer used in Example 1, a supported titanium catalyst (medium stereoregular catalyst) in which the electron donor is cyclohexylmethyldimethoxysilane is used, and the intrinsic viscosity [η] is 3.7 by two-stage polymerization. Other than using propylene homopolymers with a molecular weight distribution of 50% by weight and a low molecular weight polymer with an intrinsic viscosity [η] of 2.6 dl / g adjusted to 50% by weight and a molecular weight distribution of 50% by weight. Was carried out in the same manner as in Example 1. This polymer corresponds to a conventionally used material. The results are also shown in Table 1.

[Comparative Example 2]
A high molecular weight polymer having an intrinsic viscosity [η] of 4.3 dl / g by two-stage polymerization using a supported titanium catalyst in which the electron donor is dicyclopentyldimethoxysilane instead of the propylene polymer used in Example 1. Was adjusted to an amount of 48% by weight and a propylene homopolymer having an expanded molecular weight distribution was used in the same manner as in Example 1 except that a low molecular weight material having an intrinsic viscosity [η] of 1.9 dl / g was adjusted to an amount of 48% by weight. I did it. The results are also shown in Table 1.

[Comparative Example 3]
Instead of the propylene homopolymer used in Comparative Example 1, 80% by weight of the same propylene homopolymer as in Comparative Example 1, 15% by weight of the same high-pressure low-density polyethylene as in Example 4, and the same high-density polyethylene as in Example 4 It carried out similarly to Example 1 except having used the resin composition comprised from 5 weight%. The results are also shown in Table 1.

  A sheet obtained from the propylene-based resin or resin composition of the present invention is excellent in rigidity, heat resistance, and thermoformability, and can be suitably used as a material for thermoformed products.

It is a figure which shows the change process of the forming sheet in the heating process at the time of vacuum forming.

Explanation of symbols

1 Process 1
2 Process 2
3 Process 3
4 Process 4

Claims (7)

A propylene-based polymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms,
[1] The content of the structural unit derived from ethylene or an α-olefin having 4 to 20 carbon atoms is in the range of 0.1 to 2.0 mol%,
[2] Its melt flow rate (230 ° C, 2.16kg load) is 0.1-5.0g / 10min,
[3] Mw / Mn measured by GPC method is 5.0-20,
[4] The value of the stereoregularity index [M ₅ ] determined by the following formula (Eq-1) from the Pmmmm and Pw absorption intensities in the ¹³ C-NMR spectrum is in the range of 0.960 to 0.990.

(In the formula, [Pmmmm] indicates the absorption intensity derived from the methyl group of the third unit at the site where 5 units of the propylene unit are isotactically bonded, and [Pw] is the absorption intensity derived from the methyl group of the propylene unit. Is shown.)
A propylene-based polymer (A) characterized by   The propylene polymer according to claim 1, wherein the melting point measured by DSC is 150.0 to 163.0 ° C, and the melt tension at 230 ° C is 80 to 180 mN.   The propylene-based polymer according to claim 2, wherein the tensile elastic modulus of the 0.6 mm-thick sheet measured in accordance with ASTM-D-882 (tensile speed: 10 mm / min) is 1500 to 1900 MPa. .   A polypropylene resin comprising 70 to 98% by weight of the propylene polymer according to any one of claims 1 to 3 and 2 to 30% by weight of a polymer (Q) different from the propylene polymer. Composition (B).   The polypropylene resin composition according to claim 4, wherein the polymer (Q) is polyethylene.   A polypropylene sheet comprising the propylene-based polymer according to any one of claims 1 to 3, or a molded article obtained by thermoforming the sheet.   A polypropylene sheet comprising the polypropylene resin composition according to claim 4 or 5, or a molded article obtained by thermoforming the sheet.

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