JP6842291B2 - Polypropylene composition and its manufacturing method, and polypropylene sheet - Google Patents

Description

The present invention relates to a polypropylene composition, a method for producing the polypropylene composition, and a polypropylene sheet composed of the polypropylene composition.

Polypropylene is inexpensive, has excellent rigidity, moisture resistance, and heat resistance, and is suitable as a material for sheets used in food packaging, fiber packaging, and the like. For example, a container made of polypropylene is used as a food container with heat resistance, but there is still a problem in terms of strength, and in order to make up for it, it is possible to increase the thickness or add many ribs. Problems such as increased costs and unsightly contents arise. In addition, transparency is required for food containers so that the contents can be confirmed, but polypropylene is a crystalline resin and becomes a translucent sheet as it is, so as a remedy, addition of a crystal nucleating agent It has been known. However, it is still difficult to obtain sufficient transparency.

In order to improve the transparency of a molded product of a polypropylene composition, for example, Patent Document 1 proposes a method of adding a crystal nucleating agent. Further, a method of stretching polypropylene is known as a method for improving the rigidity and transparency of polypropylene (Patent Document 2).

International Publication No. 2013/125504 Special Table 2004-517199

However, according to the findings of the present inventors, it is difficult to achieve high transparency, high rigidity, and good sheet formability (uniform stretchability) at the same time by the methods of Patent Documents 1 and 2.

An object of the present invention is to provide a polypropylene composition capable of obtaining a sheet having excellent sheet moldability, transparency and rigidity, a method for producing the polypropylene composition, and a polypropylene sheet made of the polypropylene composition. is there.

[1] It is composed of 30 to 70% by mass of a propylene homopolymer and 30 to 70% by mass of a propylene / ethylene random copolymer, has an ethylene content of 0.5% by mass or less, and has a molecular weight distribution (Mw / Mn) of 6 to 20%. , The amount of xylene insoluble content at 25 ° C. is 97 to 99% by mass, the stereoregularity (mm mm) of xylene insoluble content is 97.5 to 99.5%, and heating and cooling are performed so that the maximum heating temperature is gradually lowered. For 100 parts by mass of the polypropylene-based polymer whose melting curve by thermal analysis when reheated after being repeated a plurality of times satisfies the following conditions (B-i) to (B-iii), and the polypropylene-based polymer. A polypropylene composition containing 0.18 to 0.5 parts by mass of a crystal nucleating agent and having a melt flow rate of 1 to 10 g / 10 minutes.
(Bi) The melting peak temperature is 165 ° C. or higher.
(B-ii) The proportion of components having a melting temperature of 170 ° C. or higher is 10% or higher.
(B-iii) The proportion of components having a melting temperature of 160 ° C. or lower is 15% or more.
[2] A polypropylene sheet made of the polypropylene composition of the above [1].
[3] The method for producing the polypropylene composition of the above [1], wherein the polypropylene-based polymer is continuously subjected to two or more stages of polymerization steps by a multi-stage polymerization method, or one of the monomer concentration and the polymerization conditions. Alternatively, a method for producing a polypropylene composition, which is produced by using a polymer having both gradients, and the obtained polypropylene-based polymer is mixed with the crystal nucleating agent.
[4] In the polymerization step, a solid catalyst containing (A) an electron donor compound selected from magnesium, titanium, halogen, and a succinate compound as an essential component; (B) an organoaluminum compound; and (C) an external compound. The method for producing a polypropylene composition according to [3], which uses a catalyst containing an electron donor compound.

The polypropylene composition of the present invention has excellent sheet moldability, and a sheet having excellent transparency and rigidity can be obtained.

It is a graph which shows an example of the temperature pattern at the time of obtaining the final melting curve. This is an example of the final melting curve.

<Measurement method>
The values of each physical property in the present invention are as follows.
[Molecular weight distribution (Mw / Mn)]
The molecular weight distribution (Mw / Mn) of the polymer or copolymer is a value obtained by measuring the mass average molecular weight (Mw) and the number average molecular weight (Mn) by gel permeation chromatography and calculating Mw / Mn. ..
PL GPC220 manufactured by Polymer Laboratories is used as an apparatus, 1,2,4-trichlorobenzene containing an antioxidant is used as a mobile phase, and UT-G (1) and UT-807 (1) manufactured by Showa Denko Co., Ltd. are used as columns. ), UT-806M (2 pieces) connected in series, and a differential refractometer was used as a detector. The same solvent as the mobile phase was used as the solvent for the sample solution, and the sample was dissolved at a sample concentration of 1 mg / mL for 2 hours while shaking at a temperature of 150 ° C. to prepare a measurement sample. 500 μL of the sample solution thus obtained was injected into the column, and measurements were taken at a flow rate of 1.0 mL / min, a temperature of 145 ° C., and a data acquisition interval of 1 second. A polystyrene standard sample having a molecular weight of 580 to 7.45 million (Shodex STANDARD, manufactured by Showa Denko KK) was used for column calibration, and the column was calibrated by a cubic approximation. The Mark-Houkins coefficient is K = 1.21 × 10 ^-4 , α = 0.707 for polystyrene standard samples, K = for polypropylene homopolymers, propylene random copolymers, and polypropylene-based polymers. 1.37 × 10 ^-4 , α = 0.75 was used.

[Amount of xylene insoluble matter]
2.5 g of polymer was dissolved in 250 ml of xylene at 135 ° C. with stirring. After 20 minutes, the solution was cooled to 25 ° C. with stirring and then allowed to stand for 30 minutes. The precipitate was filtered through filter paper, the solution was evaporated in a stream of nitrogen and the residue was dried under vacuum at 80 ° C. until a constant weight was reached. In this way, the mass% of the polymer soluble in xylene at 25 ° C. was calculated. The amount of xylene insoluble (% by weight of the xylene-insoluble polymer at 25 ° C.) is determined by (% by weight of the 100-soluble polymer) and is considered to be the amount of the isotactic component of the polymer.
The xylene insoluble component was collected by thoroughly rinsing the xylene remaining in the precipitate with methanol and then drying at 80 ° C. under vacuum.
[Tacticity of xylene insoluble (three-dimensional regularity) mm mm]
The mmmm of the xylene insoluble component obtained by the above method was obtained by using JNM LA-400 (13C resonance frequency 100 MHz) manufactured by JEOL Ltd. for a sample dissolved in a mixed solvent of 1,2,4-trichlorobenzene / deuterated benzene. ^{13 From} the spectrum measured by the C-NMR method, the ratio of the intensity of the peak corresponding to the pentad having four consecutive meso (m) bond sequences of the propylene monomer was determined by A.I. It was determined according to the method described in Zambelli, Macromolecules, 6,925 (1973).
[Melt flow rate (MFR)]
The melt flow rate of the polypropylene composition is a value measured under the conditions of a temperature of 230 ° C. and a load of 21.18 N according to JIS K7210.

<Polypropylene composition>
The polypropylene composition of the present invention contains a polypropylene polymer and a crystal nucleating agent.
The polypropylene-based polymer is composed of a propylene homopolymer and a propylene / ethylene random copolymer. The propylene homopolymer is preferably 30 to 70% by mass, more preferably 40 to 70% by mass, and even more preferably 50 to 70% by mass with respect to the polypropylene-based polymer.

The polypropylene polymer has a Mw / Mn of 6 to 20 and has a relatively wide molecular weight distribution. When the Mw / Mn is at least the lower limit of the above range, excellent rigidity can be easily obtained in the molded product made of the polypropylene composition, and when it exceeds the upper limit, it becomes difficult to produce the polypropylene polymer.

The amount of xylene insoluble in the polypropylene polymer is 97 to 99% by mass. The xylene-insoluble component of the polypropylene polymer corresponds to a crystalline isotactic component. On the other hand, the component soluble in xylene contained in a small amount in the polypropylene-based polymer corresponds to an atactic component having no crystallinity, and has a lower molecular weight than the component insoluble in xylene. Therefore, the melting properties of the polypropylene composition and the physical properties of the molded product mainly depend on the components insoluble in xylene. The amount of xylene insoluble in the polypropylene-based polymer is 97 to 99% by mass, which means that the crystalline component of the polypropylene-based polymer is 97 to 99% by mass. When the crystalline component of the polypropylene-based polymer is less than 97% by mass, the rigidity of the molded product made of the polypropylene composition is particularly lowered.
The xylene insoluble component (crystallinity component) of the polypropylene-based polymer has a stereoregularity (mm mm) of 97.5 to 99.5%. If the mm mm is less than 97.5%, the rigidity and heat resistance of the molded product made of the polypropylene composition, particularly the heat resistance, are lowered.

The ethylene content in the polypropylene-based polymer is 0.5% by mass or less, preferably less than 0.3% by mass. The lower limit is more than 0% by mass, preferably 0.1% by mass or more. Transparency is improved by randomly copolymerizing ethylene with propylene. When the ethylene content in the polypropylene-based polymer is 0.5% by mass or less, excellent rigidity can be easily obtained in a molded product made of a polypropylene composition.

The polypropylene-based polymer has a melting curve obtained by thermal analysis when it is reheated after repeating heating and cooling a plurality of times so that the maximum heating temperature is gradually lowered (hereinafter, this melting curve is referred to as a "final melting curve". ) Satisfy the following conditions (B-i) to (B-iii).
(Bi) The melting peak temperature is 165 ° C. or higher. Preferably, the melting peak temperature is 167 ° C. or higher, more preferably 169 ° C. or higher. The melting peak temperature is substantially 186 ° C. or lower.
(B-ii) The proportion of components having a melting temperature of 170 ° C. or higher is 10% or higher. Preferably, the proportion of the component having a melting temperature of 170 ° C. or higher is 15% or higher, more preferably 20% or higher.
(B-iii) The proportion of components having a melting temperature of 160 ° C. or lower is 15% or more. Preferably, the proportion of the component having a melting temperature of 160 ° C. or lower is 18% or more, more preferably 20% or more.
When the melting peak temperature of the polypropylene-based polymer is less than 165 ° C., or the proportion of the components having a melting temperature of 170 ° C. or higher is less than 10%, the rigidity of the molded product made of the polypropylene composition becomes insufficient. Further, if the proportion of the components whose melting temperature is 160 ° C. or lower is less than 15%, the moldability becomes insufficient.

Here, the final melting curve will be described.
The final melting curve is obtained using a conventional differential thermal analyzer (DSC). Specifically, first, the measurement sample is once melted and then cooled. Next, as shown in FIG. 1, heating and cooling are repeated a plurality of times so that the maximum heating temperature is sequentially lowered, and then reheating is performed, and thermal analysis of the measurement sample at the time of the reheating is performed to obtain a final melting curve. obtain. The thermal analysis of the final melting curve is similar to that of a normal DSC and is simple.
FIG. 2 shows an example of the final melting curve. The peak temperature (Tmp) in this final melting curve is _defined as the melting peak temperature.
In the heat treatment in which heating and cooling are repeated multiple times so that the maximum heating temperature is gradually lowered, annealing of the measurement sample and crystallization by subsequent cooling are repeated sequentially from the high temperature, and as a result, crystals can be easily crystallized in order from the molecule with the fewest defects. Can be formed. In addition, crystals composed of defective molecules formed at a low temperature during cooling melt while being continuously heated and held at the maximum heating temperature until the maximum heating temperature becomes sufficiently low. Hereinafter, the heat treatment in which heating and cooling are repeated a plurality of times so that the maximum heating temperature is sequentially lowered is referred to as "repeated annealing treatment".
The heating and cooling in the iterative annealing, for example, heated at a constant heating rate until Ts _1, after holding the temperature was cooled to 20 ° C. at a constant cooling rate, then, Ts 1 _-5 [℃] (This temperature is _{defined as Ts 2.} ) The temperature is maintained at a constant temperature rise rate, and then cooled to 20 ° C. at a constant temperature decrease rate. Thereafter, the maximum heating temperature Ts _n during the n-th heating _{Ts 1 -5 × (n-1} ) repeating the heating and cooling such that the [° C.]. Repeating until Ts _n reaches 80 ° C. gives highly reliable results even for components with many defects.
Further, in the reheating when obtaining the final melting curve, in order to obtain the melting behavior of all the crystals obtained by annealing at each maximum heating temperature and crystallization during subsequent cooling, 20 at a constant heating rate. The temperature is raised from ° C to 200 ° C or higher. Crystals made up of molecules with few defects crystallized at high temperatures have a high melting point, while crystals made up of molecules with many defects crystallized at low temperatures have a low melting point, so the final melting curve reflects the distribution of defects in the sample.

The ratio of the components whose melting temperature is 170 ° C. or higher is the ratio of the melting enthalpy at 170 ° C. or higher to the total melting enthalpy obtained from the final melting curve. On the other hand, the ratio of the components whose melting temperature is 160 ° C. or lower is the ratio of the melting enthalpy at 160 ° C. or lower to the total melting enthalpy obtained from the final melting curve.
In each case, it is calculated as the ratio of the partial area to the total area of the melting peak on the baseline.

The MFR of the polypropylene composition of the present invention is 1 to 10 g / 10 minutes, preferably 2 to 7 g / 10 minutes. When the MFR is at least the lower limit of the above range, excellent moldability can be easily obtained when the polypropylene composition is molded into a sheet. If it is not more than the upper limit value, excellent secondary formability can be easily obtained when the sheet is thermoformed.

The polypropylene composition of the present invention contains a crystal nucleating agent. The addition of the crystal nucleating agent contributes to the improvement of transparency. Specific examples of the crystal nucleating agent will be described later.
The content of the crystal nucleating agent is 0.18 to 0.5 parts by mass, preferably 0.2 to 0.4 parts by mass, based on 100 parts by mass of the polypropylene polymer in the polypropylene composition. When the content of the crystal nucleating agent is 0.18 parts by mass or more, the transparency improving effect is excellent. Even if it exceeds 0.5 parts by mass, further improvement in transparency cannot be expected and the cost increases.

[Crystal nucleating agent]
The crystal nucleating agent is preferably selected from nonitol-based nucleating agents, sorbitol-based nucleating agents, phosphate ester-based nucleating agents, triaminobenzene derivative nucleating agents, carboxylic acid metal salt nucleating agents, and xylitol-based nucleating agents. In particular, for the purpose of improving transparency, it is more preferable to use a nonitol-based nucleating agent or a sorbitol-based nucleating agent.
Crystal nucleating agents having a nonitol-based structure include, for example, 1,2,3-trideoxy-4,6: 5,7-bis-[(4-propylphenyl) methylene] -nonitol, crystals having a xylitol-based structure. As nuclear agents, for example, bis-1,3: 2,4- (5', 6', 7', 8'-tetrahydro-2-naphthaldehyde benzylidene) 1-allylxylitol, bis-1,3: 2, 4- (3', 4'-Dimethylbenzylidene) 1-propylxylitol, as a crystal nucleating agent having a sorbitol-based structure, for example, bis-1,3: 2,4- (4'-ethylbendylidene) 1-allyl Sorbitol, bis-1,3: 2,4- (3'-methyl-4'-fluoro-benzylene) 1-propyl sorbitol, bis-1,3: 2,4- (3', 4'-dimethylbenzylene) 1'-Methyl-2'-propenyl sorbitol, bis-1,3,2,4-dibenzylidene 2', 3'-dibromopropyl sorbitol, bis-1,3,2,4-dibenzylidene 2'-bromo- 3'-Hydroxypropyl sorbitol, bis-1,3: 2,4- (3'-bromo-4'-ethylbenzylidene) -1-allyl sorbitol, mono 2,4- (3'-bromo-4'-ethyl Benzylidene) -1-allyl sorbitol, bis-1,3: 2,4- (4'-ethylbenzylidene) 1-allyl sorbitol, bis-1,3: 2,4- (3', 4'-dimethylbenzylidene) Examples thereof include 1-methylsorbitol, bis (p-methylbenzylene) sorbitol, 1,3: 2,4-bis-o- (4-methylbenzylidene) -D-sorbitol and the like.
Examples of nonitol-based commercially available crystal nucleating agents used in the composition of the present invention include Millad NX8000 (Milliken Japan), and sorbitol-based commercially available crystal nucleating agents include RiKAFAST R-1 (New Japan Chemical Co., Ltd.) and Millad 3988 (Milliken). Japan), Gelol E-200 (New Japan Chemical), Gelall MD (New Japan Chemical), etc. Examples of the phosphoric acid ester-based crystal nucleating agent include aluminum-bis (4,4', 6,6'-tetra-tert-butyl-2,2'-methylenediphenyl-phosphate) -hydroxydo. Examples of commercially available phosphoric acid ester-based crystal nucleating agents used in the composition of the present invention include Ascastab NA-21 (ADEKA) and Ascastab NA-71 (ADEKA). Examples of the triaminobenzene derivative crystal nucleating agent include 1,3,5-tris (2,2-dimethylpropanamide) benzene. Examples of commercially available triaminobenzene derivative crystal nucleating agents used in the composition of the present invention include IRGACLEAR XT386 (BASF Japan). Examples of the carboxylic acid metal salt nucleating agent include 1,2-cyclohexanedicarboxylate calcium salt and the like. Examples of commercially available carboxylic acid metal salt nucleating agents used in the composition of the present invention include Hyperform HPN-20E (Milliken Japan).
In particular, in order to maintain transparency after secondary processing (heating), it is preferable to use a nonitol-based nucleating agent, a sorbitol-based nucleating agent, or a phosphate ester-based nucleating agent.
These crystal nucleating agents can be used alone or in combination of two or more.

[Other additives]
The polypropylene composition of the present invention may contain additives other than the crystal nucleating agent as long as the effects of the present invention are not impaired.
Examples of other additives include antioxidants, neutralizers, chlorine absorbers, heat stabilizers, light stabilizers, UV absorbers, internal lubricants, external lubricants, antiblocking agents, antistatic agents, antifogging agents. , Flame retardants, dispersants, copper damage inhibitors, plasticizers, crosslinkers, peroxides, oil spreads and other conventional additives commonly used for polyolefins such as organic and inorganic pigments. The amount of each additive added may be a known amount.

[Manufacturing method of polypropylene composition]
The polypropylene composition of the present invention is obtained by producing a polypropylene-based polymer and mixing it with a crystal nucleating agent and, if necessary, other additives.
The propylene homopolymer is obtained by supplying a propylene monomer, a catalyst, and a molecular weight modifier, if necessary, to the reaction system and polymerizing the propylene monomer.
The propylene / ethylene random copolymer is obtained by supplying a propylene monomer, an ethylene monomer, a catalyst, and if necessary, a molecular weight modifier to the reaction system, and copolymerizing the propylene monomer and the ethylene monomer.
As the polymerization method, a known method such as a slurry process (polymerization in a liquid monomer) or a gas phase polymerization can be used.
A molecular weight modifier known in the art, such as a chain transfer agent (eg, hydrogen or ZnEt _{2), may be used.}
The polymerization temperature is preferably 40 to 100 ° C., more preferably 50 to 90 ° C., and even more preferably 60 to 90 ° C. When the polymerization temperature is less than the lower limit of the above range, the productivity and the stereoregularity of the obtained polypropylene are lowered.
The polymerization pressure is preferably in the range of 25 to 45 bar (2.5 to 4.5 MPa), more preferably 27 to 45 bar (2.7 to 4.5 MPa) when carried out in the liquid phase. When it is carried out in the gas phase, it is preferably in the range of 5 to 30 bar (0.5 to 3.0 MPa), more preferably 8 to 30 bar (0.8 to 3.0 MPa).

The polypropylene-based polymer is preferably obtained by a multi-stage polymerization method having two or more stages of polymerization, in which subsequent polymerization is carried out in the presence of a product formed during the immediately preceding polymerization reaction. Alternatively, it may be produced by melt-kneading a prepolymerized propylene homopolymer and a propylene / ethylene random copolymer.
The multi-stage polymerization method is preferable because a polypropylene-based polymer satisfying the above conditions (B-i) to (B-iii) can be easily obtained.
The number and order of the multi-stage polymerization are not particularly limited, and generally 2 to 5 stages are used, and an appropriate order is selected in consideration of productivity and the like. In the multi-stage polymerization method, the polymer obtained in both stages is formed by performing the second-stage polymerization by the catalyst dispersed in the polymer component formed in the first-stage polymerization. Disperses in a state close to the molecular level.
The polymerization step of each stage in the multi-stage polymerization method may be carried out by a slurry method in which an inert hydrocarbon such as hexane, heptane or kerosene or a liquefied α-olefin solvent such as propylene is present, or a vapor phase under no solvent. It may be carried out by a polymerization method, or these may be combined.
As the reactor in the polymerization step of each stage, for example, a stirring layer type reactor, a fluidized bed type reactor, a circulation type reactor and the like can be used, and any of continuous type, semi-batch type and batch type can be produced. ..
Further, in order to obtain a polypropylene-based polymer satisfying the above conditions (B-i) to (B-iii), a polymer having a gradient of monomer concentration and polymerization conditions may be used. In such a polymerizer, for example, one in which at least two polymerization regions are connected can be used, and the monomer can be polymerized by vapor phase polymerization. Specifically, in the presence of a catalyst, a monomer is supplied and polymerized in a polymerization region consisting of an ascending tube, and a monomer is supplied and polymerized by a descending tube connected to the ascending tube. The polymer product is recovered while circulating. This method comprises means to prevent the gas mixture present in the ascending tube from entering the descending tube in whole or in part. Also, a gas and / or liquid mixture having a composition different from that of the gas mixture present in the ascending tube is introduced into the descending tube. As the above polymerization method, for example, the method described in JP-A-2002-520426 can be applied.

When the polypropylene-based polymer of the present invention is produced by a multi-stage polymerization method, for example, a propylene homopolymer is produced in the first stage, and then a polymerization catalyst is further added in the presence of the propylene homopolymer in the second stage. A method of producing a propylene / ethylene random copolymer can be used without any problem.
For example, it is preferable to carry out the first step by the slurry method and the second step by the vapor phase polymerization method in that a copolymer having high solubility in propylene is easily produced. Further, it is preferable from the viewpoint of productivity that all the steps are carried out by the slurry method.

In the production of polypropylene-based polymers, it is preferable to carry out homopolymerization of propylene and copolymerization of propylene and ethylene using a catalyst component containing the following components (A), (B) and (C).
Component (A): A solid catalyst containing magnesium, titanium, halogen, and an electron donor compound selected from a succinate compound as an electron donor compound as an essential component.
(B) Component: Organoaluminium compound.
Component (C): External electron donor compound selected from silicon compounds.

[(A) component: solid catalyst]
The component (A) can be prepared by a known method, for example, by bringing a magnesium compound, a titanium compound and an electron donor compound into mutual contact.
As the titanium compound used for the preparation of the component (A), a tetravalent titanium compound represented by _{the general formula: Ti (OR) g} X _{4-g is suitable.} In the formula, R is a hydrocarbon group, X is a halogen, and 0 ≦ g ≦ 4. As titanium compounds, TiCl ₄ and more specifically, TiBr _4, titanium tetrahalides such as _{TiI 4; Ti (OCH 3)} Cl 3, Ti (OC 2 H 5) Cl 3, Ti (O n -C 4 H ₉ ) _{Trihalogenated alkoxytitanium such as Cl 3} , Ti (OC ₂ H ₅ ) Br ₃ , Ti (OisoC ₄ H ₉ ) Br ₃ ; Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl _{2, Ti (O n -C 4} H 9) 2 Cl 2, Ti (OC 2 H 5) 2 dihalogenated alkoxy titanium such as _{Br 2; Ti (OCH 3)} 3 Cl, Ti (OC 2 H 5) 3 Cl _{, Ti (O n -C 4 H} 9) 3 Cl, Ti (OC 2 H 5) monohalide trialkoxy titanium such as _{3 Br; Ti (OCH 3)} 4, Ti (OC 2 H 5) 4, Ti ( such as O _n -C ₄ tetraalkoxy titanium such as H _{9) 4} and the like. Among these, a halogen-containing titanium compound, particularly titanium tetrahalogenate, is preferable, and a more particularly preferable one is titanium tetrachloride.

Examples of the magnesium compound used for preparing the component (A) include magnesium compounds having a magnesium-carbon bond or a magnesium-hydrogen bond, such as dimethylmagnesium, diethylmagnesium, dipropylmagnesium, dibutylmagnesium, diamilmagnesium, dihexylmagnesium, and dihexylmagnesium. Examples thereof include decyl magnesium, ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride, hexyl magnesium chloride, amyl magnesium chloride, butyl ethoxymagnesium, ethyl butyl magnesium, and butyl magnesium hydride. These magnesium compounds can be used in the form of a complex compound with, for example, organoaluminum, and may be in a liquid state or a solid state. More suitable magnesium compounds include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride; magnesium methoxychloride, magnesium ethoxychloride, magnesium isopropoxychloride, magnesium butoxychloride, magnesium octoxychloride. Alkoxymagnesium halide; Allyloxymagnesium halides such as phenoxymagnesium chloride, methylphenoxymagnesium chloride; alkoxymagnesium such as ethoxymagnesium, isopropoxymagnesium, butoxymagnesium, n-octoxymagnesium, 2-ethylhexoxymagnesium; phenoxy Alyloxymagnesium such as magnesium and dimethylphenoxymagnesium; magnesium carboxylates such as magnesium laurate and magnesium stearate can be mentioned.

The electron donor compound used for the preparation of the component (A) is generally referred to as an "internal electron donor". In the present invention, it is preferable to use an internal electron donor that gives a wide molecular weight distribution. The composition polymerized using the catalyst is a composition having the same molecular weight distribution obtained by pelleting or powder blending a polymer polymerized using another catalyst, or by a multi-stage polymerization method, or by a monomer concentration or polymerization. It exhibits different properties from the composition having the same molecular weight distribution polymerized by the method using a polymerizer having a gradient of conditions. This is because the composition produced by using the catalyst is integrated with the high molecular weight component and the low molecular weight component in a state closer to the molecular level, but the latter resin composition is mixed in a state close to the molecular level. It is considered that they do not match and only apparently show the same molecular weight distribution. However, it is not realistic to express this in words in the claims. Hereinafter, preferred internal electron donors will be described.

(Internal electron donor)
The preferred internal electron donor in the present invention is a succinate compound. In the present invention, the succinate compound refers to a succinic acid diester or a substituted succinic acid diester. Hereinafter, the succinate compound will be described in detail. The succinate-based compound preferably used in the present invention is represented by the following formula (I).

In the formula, the groups R ₁ and R ₂ are linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, or alkyl of _{C 1 to} C ₂₀ , which are the same or different from each other and sometimes contain a heteroatom. Aryl groups; groups R _{3 to} R ₆ are linear or branched alkyl, alkenyl, cycloalkyl, aryl, of _{C 1 to} C ₂₀ , which are identical or different from each other and contain hydrogen or, in some cases, heteroatoms. _{Groups R 3 to} R ₆ , which are arylalkyl or alkylaryl groups and are bonded to the same carbon atom or different carbon atoms, may be bonded together to form a ring.

R ₁ and R ₂ are preferably C _1- C ₈ alkyl, cycloalkyl, aryl, arylalkyl, and alkylaryl groups. Compounds in which R ₁ and R ₂ are selected from primary alkyls, particularly branched primary alkyls, are particularly preferred. Examples of suitable R ₁ and R ₂ groups are C _1- C ₈ alkyl groups, such as methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, 2-ethylhexyl. Ethyl, isobutyl, and neopentyl are particularly preferred.

One of the preferred groups of compounds represented by formula (I) is branched alkyl, cycloalkyl, aryl, arylalkyl _{, where R 3 to} R ₅ are hydrogen and R _{6 has 3 to 10 carbon atoms.} , And an alkylaryl group. Preferred specific examples of such a monosubstituted succinate compound are diethyl-sec-butyl succinate, diethyl texyl succinate, diethyl cyclopropyl succinate, diethyl norbonyl succinate, diethyl perihydro succinate, diethyl. Trimethylsilyl succinate, diethyl methoxy succinate, diethyl-p-methoxyphenyl succinate, diethyl-p-chlorophenyl succinate, diethyl phenyl succinate, diethyl cyclohexyl succinate, diethyl benzyl succinate, diethyl cyclohexyl Methyl succinate, diethyl-t-butyl succinate, diethyl isobutyl succinate, diethyl isopropyl succinate, diethyl neopentyl succinate, diethyl isopentyl succinate, diethyl (1-trifluoromethyl ethyl) succinate , Diethylfluorenyl succinate, 1-ethoxycarbodiisobutylphenyl succinate, diisobutyl-sec-butyl succinate, diisobutyltexyl succinate, diisobutylcyclopropyl succinate, diisobutylnorbonyl succinate, diisobutylperihydro Succinate, diisobutyltrimethylsilyl succinate, diisobutylmethoxysuccinate, diisobutyl-p-methoxyphenyl succinate, diisobutyl-p-chlorophenyl succinate, diisobutylcyclohexylsuccinate, diisobutylbenzyl succinate, diisobutylcyclohexylmethyl Succinate, diisobutyl-t-butyl succinate, diisobutylisobutyl succinate, diisobutylisopropyl succinate, diisobutylneopentyl succinate, diisobutylisopentyl succinate, diisobutyl (1-trifluoromethylethyl) succinate, Diisobutylfluorenyl succinate, dineopentyl-sec-butyl succinate, dineopentyltexyl succinate, geneopentylcyclopropyl succinate, dineopentyl norbonyl succinate, dineopentyl perihydrosuccinate , Dineopentyltrimethylsilyl succinate, dineopentylmethoxysuccinate, geneopentyl-p-methoxyphenyl succinate, geneopentyl-p-chlorophenyl succinate, geneopentylphenyl succinate, genine Opentyl Cyclohexyl succinate, Dineopentyl benzyl succinate, Dineopentyl cyclohexylmethyl succinate, Dineopentyl-t-butyl succinate, Dineopentyl isobutyl succinate, Dineopentyl isopropyl succinate, Di Neopentyl neopentyl succinate, dineopentyl isopentyl succinate, dineopentyl (1-trifluoromethylethyl) succinate, dineopentyl fluorenyl succinate.

Another preferred group of compounds within the range of formula (I) is a _{linear C 1 to} C ₂₀ in which _{at least two groups from R 3 to} R ₆ differ from hydrogen and in some cases contain heteroatoms. Alternatively, it is selected from branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, or alkylaryl groups. A compound in which two groups different from hydrogen are bonded to the same carbon atom is particularly preferable. Specifically, it is a compound in which _{R 3} and R ₄ are different groups from hydrogen, and R ₅ and R _{6 are hydrogen atoms.} Preferred specific examples of such disubstituted succinates are diethyl-2,2-dimethylsuccinate, diethyl-2-ethyl-2-methylsuccinate, diethyl-2-benzyl-2-isopropylsuccinate, diethyl. -2-Cyclohexylmethyl-2-isobutyl succinate, diethyl-2-cyclopentyl-2-n-butyl succinate, diethyl-2,2-diisobutyl succinate, diethyl-2-cyclohexyl-2-ethyl succinate Nate, diethyl-2-isopropyl-2-methylsuccinate, diethyl-2-tetradecyl-2-ethylsuccinate, diethyl-2-isobutyl-2-ethylsuccinate, diethyl-2- (1-trifluoro) Methylethyl) -2-methylsuccinate, diethyl-2-isopentyl-2-isobutylsuccinate, diethyl-2-phenyl-2-n-butylsuccinate, diisobutyl-2,2-dimethylsuccinate, Diisobutyl-2-ethyl-2-methylsuccinate, diisobutyl-2-benzyl-2-isopropylsuccinate, diisobutyl-2-cyclohexylmethyl-2-isobutylsuccinate, diisobutyl-2-cyclopentyl-2-n- Butyl succinate, diisobutyl-2,2-diisobutyl succinate, diisobutyl-2-cyclohexyl-2-ethyl succinate, diisobutyl-2-isopropyl-2-methylsuccinate, diisobutyl-2-tetradecyl-2- Ethyl succinate, diisobutyl-2-isobutyl-2-ethyl succinate, diisobutyl-2- (1-trifluoromethylethyl) -2-methyl succinate, diisobutyl-2-isopentyl-2-isobutyl succinate , Diisobutyl-2-phenyl-2-n-butyl succinate, dineopentyl-2,2-dimethylsuccinate, dineopentyl-2-ethyl-2-methylsuccinate, dineopentyl-2-benzyl-2-isopropyls Xinate, Dineopentyl-2-cyclohexylmethyl-2-isobutyl succinate, Dineopentyl-2-cyclopentyl-2-n-butyl succinate, Dineopentyl-2,2-diisobutyl succinate, Dineopentyl-2-cyclohexyl-2 -Ethyl succinate, dineopentyl-2-isopropyl-2-methyl succinate, dineopentyl-2-tetradecyl-2-ethyl succine , Dineopentyl-2-isobutyl-2-ethyl succinate, dineopentyl-2- (1-trifluoromethylethyl) -2-methylsuccinate, dineopentyl-2-isopentyl-2-isobutyl succinate, dineopentyl It is -2-phenyl-2-n-butyl succinate.

Further, compounds in which at least two groups different from hydrogen are bonded to different carbon atoms are also particularly preferable. Specifically, it is _{a compound in which R 3} and R ₅ are different groups from hydrogen. In this case, R ₄ and R ₆ may be hydrogen atoms or groups different from hydrogen, but it is preferable that one of them is a hydrogen atom (trisubstituted succinate). Preferred specific examples of such compounds are diethyl-2,3-bis (trimethylsilyl) succinate, diethyl-2,2-sec-butyl-3-methylsuccinate, diethyl-2- (3,3,3-). Trifluoropropyl) -3-methylsuccinate, diethyl-2,3-bis (2-ethylbutyl) succinate, diethyl-2,3-diethyl-2-isopropylsuccinate, diethyl-2,3-diisopropyl-2 -Methyl succinate, diethyl-2,3-dicyclohexyl-2-methyldiethyl-2,3-dibenzylsuccinate, diethyl-2,3-diisopropylsuccinate, diethyl-2,3-bis (cyclohexylmethyl) ) Succinate, diethyl-2,3-di-t-butyl succinate, diethyl-2,3-diisobutyl succinate, diethyl-2,3-dineopentyl succinate, diethyl-2,3-diiso Pentyl succinate, diethyl-2,3- (1-trifluoromethylethyl) succinate, diethyl-2,3-tetradecyl succinate, diethyl-2,3-fluorenyl succinate, diethyl-2-isopropyl -3-Isobutyl succinate, diethyl-2-tert-butyl-3-isopropyl succinate, diethyl-2-isopropyl-3-cyclohexyl succinate, diethyl-2-isopentyl-3-cyclohexyl succinate, diethyl -2-Tetradecyl-3-cyclohexylmethyl succinate, diethyl-2-cyclohexyl-3-cyclopentyl succinate, diisobutyl-2,3-diethyl-2-isopropylsuccinate, diisobutyl-2,3-diisopropyl-2 -Methyl succinate, diisobutyl-2,3-dicyclohexyl-2-methylsuccinate, diisobutyl-2,3-dibenzylsuccinate, diisobutyl-2,3-diisopropylsuccinate, diisobutyl-2,3- Bis (cyclohexylmethyl) succinate, diisobutyl-2,3-di-t-butyl succinate, diisobutyl-2,3-diisobutyl succinate, diisobutyl-2,3-dineopentyl succinate, diisobutyl-2, 3-Diisopentyl succinate, diisobutyl-2,3- (1-trifluoromethylethyl) succinate, diisobutyl-2,3-tetradecyl succinate, diisobutyl-2,3-fluorenyl succinate , Diisobutyl-2-isopropyl-3-isobutyl succinate, diisobutyl-2-tert-butyl-3-isopropyl succinate, diisobutyl-2-isopropyl-3-cyclohexyl succinate, diisobutyl-2-isopentyl-3-3 Cyclohexyl succinate, diisobutyl-2-tetradecyl-3-cyclohexylmethyl succinate, diisobutyl-2-cyclohexyl-3-cyclopentyl succinate, dineopentyl-2,3-bis (trimethylsilyl) succinate, dineopentyl-2,2- sec-Butyl-3-methylsuccinate, dineopentyl-2- (3,3,3-trifluoropropyl) -3-methylsuccinate, dineopentyl-2,3-bis (2-ethylbutyl) succinate, dineopentyl- 2,3-Diethyl-2-isopropyl succinate, dineopentyl-2,3-diisopropyl-2-methyl succinate, dineopentyl-2,3-dicyclohexyl-2-methyl succinate, dineopentyl-2,3-di Benzyl succinate, dineopentyl-2,3-diisopropyl succinate, dineopentyl-2,3-bis (cyclohexylmethyl) succinate, dineopentyl-2,3-di-t-butyl succinate, dineopentyl-2,3- Diisobutyl succinate, geneopentyl-2,3-dineopentyl succinate, dineopentyl-2,3-diisopentyl succinate, dineopentyl-2,3- (1-trifluoromethylethyl) succinate, dineopentyl-2 , 3-Tetradecyl succinate, dineopentyl-2,3-fluorenyl succinate, dineopentyl-2-isopropyl-3-isobutyl succinate, dineopentyl-2-tert-butyl-3-isopropyl succinate, dineopentyl -2-Isopropyl-3-cyclohexyl succinate, dineopentyl-2-isopentyl-3-cyclohexyl succinate, dineopentyl-2-tetradecyl-3-cyclohexylmethyl succinate, dineopentyl-2-cyclohexyl-3-cyclopentyl succinate Nate.

Among the compounds of formula (I), a compound some are bonded to form a ring together of the radicals R ₃ to R ₆ may be also preferably used. As such compounds, the compounds listed in Special Table 2002-542347, for example, 1- (ethoxycarbonyl) -1- (ethoxyacetyl) -2,6-dimethylcyclohexane, 1- (ethoxycarbonyl) -1-( Ethoxyacetyl) -2,5-1 dimethylcyclopentane, 1- (ethoxycarbonyl) -1- (ethoxyacetylmethyl) -21methylcyclohexane, 1- (ethoxycarbonyl) -1- (ethoxy (cyclohexyl) acetyl) cyclohexane Can be mentioned. Alternatively, cyclic succinate compounds such as diisobutyl 3,6-dimethylcyclohexane-1,2-dicarboxylic acid and diisobutyl cyclohexane-1,2-dicarboxylic acid, as disclosed in WO 2009/069483, are also preferred. Can be used. As an example of other cyclic succinate compounds, the compounds disclosed in WO 2009/057747 are also preferred.

Among the compounds of formula (I), if the group R ₃ to R ₆ is a hetero atom, it heteroatom is 16 atoms containing Group 15 atom or an oxygen and sulfur atom containing nitrogen and phosphorus atoms preferable. Examples of the compound in which the groups R _{3 to} R ₆ contain a Group 15 atom include compounds disclosed in JP-A-2005-306910. On the other hand, groups _R 3 to R ₆ are Examples of the compound containing a Group 16 atom include compounds disclosed in JP-2004-131537.

In addition, an internal electron donor that gives a molecular weight distribution equivalent to that of the succinate compound may be used. Examples of such an internal electron donor include diphenyldicarboxylic acid esters described in JP2013-28704, cyclohexenedicarboxylic acid esters described in JP2014-2016002, and JP2013-28705. Dicycloalkyldicarboxylic acid ester, diol dibenzoate described in Japanese Patent No. 4959920, 1,2-phenylenedibenzoate described in International Publication No. 2010/078494.

[Component (B): Organoaluminium compound]
Examples of the organoaluminum compound as the component (B) include the following.
Trialkylaluminum such as triethylaluminum and tributylaluminum;
Trialkenyl aluminum such as triisoprenyl aluminum:
Dialkylaluminum alkoxides such as diethylaluminum ethoxide and dibutylaluminum butoxide;
Alkylaluminum sesquialkoxides such as ethylaluminum sesquiethoxydo and butylaluminum sesquibutoxide;
Partially halogenated alkylaluminum such as alkylaluminum dihalogenide such as ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromid;
Dialkylaluminum hydrides such as diethylaluminum hydride, dibutylaluminum hydride;
Partially hydrogenated alkylaluminum such as alkylaluminum dihydrides such as ethylaluminum dihydrides and propylaluminum dihydrides;
Partially alkoxylated and halogenated alkylaluminum such as ethylaluminum ethoxychloride, butylaluminum butokicyclolide, ethylaluminum ethoxybromid.

[Component (C): electron donor compound]
The electron donor compound of the component (C) is generally referred to as an "external electron donor". As such an electron donor compound, an organosilicon compound is preferable. Preferred organosilicon compounds include:
Trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-amylmethyldiethoxysilane, diphenyldimethoxysilane, phenylmethyl Dimethoxysilane, diphenyldiethoxysilane, biso-tolyldimethoxysilane, bism-tolyldimethoxysilane, bisp-tolyldimethoxysilane, bisp-tolyldiethoxysilane, bisethylphenyldimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane Silane, Cyclohexylmethyldimethoxysilane, Cyclohexylmethyldiethoxysilane, Ethyltrimethoxysilane, Ethyltriethoxysilane, Vinyltrimethoxysilane, Methyltrimethoxysilane, n-propyltriethoxysilane, Decyltrimethoxysilane, Decyltriethoxysilane, Phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, t-butyltriethoxysilane, texyltrimethoxysilane, n-butyltriethoxysilane, iso- Butyltriethoxysilane, phenyltriethoxysilane, γ-aminopropyltriethoxysilane, chlortriethoxysilane, ethyltriisopropoxysilane, vinyltributoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, 2-norbornantrimethoxysilane , 2-Norbornantriethoxysilane, 2-norbornanmethyldimethoxysilane, ethyl silicate, butyl silicate, trimethylphenoxysilane, methyltriallyloxysilane, vinyltris (β-methoxyethoxysilane), vinyltriacetoxysilane, dimethyl Tetraethoxydisiloxane.
Among them, ethyltriethoxysilane, n-propyltriethoxysilane, n-propyltrimethoxysilane, t-butyltriethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-butylethyldimethoxysilane, t-Butylpropyldimethoxysilane, t-butylt-butoxydimethoxysilane, t-butyltrimethoxysilane, i-butyltrimethoxysilane, isobutylmethyldimethoxysilane, i-butylsec-butyldimethoxysilane, ethyl (perhydroisoquinolin 2-) Il) dimethoxysilane, bis (decahydroisoquinolin-2-yl) dimethoxysilane, tri (isopropeniroxy) phenylsilane, texyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltri Butoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, i-butyl i-propyldimethoxysilane, cyclopentyl t-butoxydimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexyl i-butyldimethoxysilane, cyclopentyl i -Butyldimethoxysilane, cyclopentylisopropyldimethoxysilane, di-sec-butyldimethoxysilane, diethylaminotriethoxysilane, tetraethoxysilane, tetramethoxysilane, isobutyltriethoxysilane, phenylmethyldimethoxysilane, phenyltriethoxylan, bisp-tolyl Dimethoxysilane, p-tolylmethyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylethyldimethoxysilane, 2-norbornantriethoxysilane, 2-norbornanmethyldimethoxysilane, diphenyldiethoxysilane, methyl (3,3,3-trifluoropropyl) Dimethoxysilane, ethyl silicate and the like are preferable.

In the production of the polypropylene-based polymer, it is preferable to bring the raw material monomer into contact with the catalyst prepared as described above to polymerize. At this time, it is preferable to first perform prepolymerization using the catalyst. The prepolymerization is a step of forming a polymer chain as a foothold for the subsequent main polymerization of the raw material monomer in the solid catalyst component. Prepolymerization can be carried out by a known method. Prepolymerization is usually carried out at 40 ° C. or lower, preferably 30 ° C. or lower, and more preferably 20 ° C. or lower.
Next, the prepolymerized catalyst is introduced into the polymerization reaction system, and the main polymerization of the raw material monomer is carried out to produce a polypropylene-based polymer.

The polypropylene polymer thus obtained by polymerization, the crystal nucleating agent, and other additives as required are stirred with a Henschel mixer, brabender, etc., and then melt-blended at 180 ° C. to 280 ° C. using an extruder. By doing so, the polypropylene composition of the present invention can be obtained. The crystal nucleating agent and other additives may be added using a connected extruder after undergoing polymerization, residual monomer removal, and drying steps. Further, in the present invention, a so-called masterbatch in which a high-concentration crystal nucleating agent is melt-kneaded with a polypropylene-based polymer may be mixed with the polypropylene-based polymer at the time of sheet molding.

<Polypropylene sheet>
The polypropylene sheet of the present invention comprises the polypropylene composition of the present invention. The polypropylene sheet may be a single layer or a multi-layered laminate. The thickness of the polypropylene sheet is preferably 150 to 3000 μm, more preferably 150 to 2000 μm. If the thickness is less than 150 μm, the rigidity tends to be insufficient. If the rigidity is insufficient, it is not suitable for sheet materials used for food packaging and textile packaging. If the thickness exceeds 3000 μm, the cost simply increases, which is not realistic in the case of industrial mass production at low cost.

<Manufacturing method of polypropylene sheet>
The method for producing the polypropylene sheet of the present invention is not particularly limited. For example, it may be an unstretched sheet made of the polypropylene composition of the present invention, or a sheet obtained by biaxially stretching the unstretched sheet.
The unstretched sheet manufacturing step and the biaxial stretching step can be performed by using a known method.
The unstretched sheet can be produced by winding the resin melted by the extruder with a cooling roll. The T-die extrusion method is preferable as the melt extrusion method. Examples of the cooling step include widely known cooling methods such as water cooling, air cooling, rolls and belts, but it is preferable that the molten resin is uniformly and efficiently rapidly cooled for the purpose of obtaining transparency with a small amount of crystal nucleating agent. , Belt method (Patent No. 4237275), sleeve rubber roll method (Patent No. 4472018), swing roll method (Patent No. 4701067) and the like may be used in combination. The temperature of the molten resin in the extruder is preferably 200 to 250 ° C, and the cooling roll temperature is preferably 20 to 90 ° C.
The molding temperature when biaxially stretching the unstretched sheet is preferably 140 to 170 ° C, more preferably 150 to 165 ° C, still more preferably 155 to 160 ° C.

<Manufacturing method of secondary molded product made of polypropylene sheet>
The polypropylene sheet of the present invention can be easily processed into a container or a tray by a known thermoforming method such as vacuum forming, vacuum pressure forming, or thermoforming. The secondary molded product can be used as a lunch box container, a more prepared food tray, a heat insulating container, and the like. The thickness of the secondary molded product is preferably 150 to 1000 μm, more preferably 150 to 400 μm. If the thickness is less than 150 μm, the rigidity tends to be insufficient. If the rigidity is insufficient, it is not suitable for sheet materials used for food packaging and textile packaging. If the thickness exceeds 1000 μm, the cost will simply increase, which is not realistic for industrial mass production at low cost.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
<Measurement method / evaluation method>
[Ethethylene content in polypropylene polymer]
^{For the ethylene content in the polypropylene polymer, JNM LA-400 (13C} resonance frequency 100 MHz) manufactured by JEOL Ltd. was used for the sample dissolved in the mixed solvent of 1,2,4-trichlorobenzene / deuterated benzene. , ¹³ Calculated from the values measured by the C-NMR method.

[Analysis of final melting curve]
The analysis of the final melting curve was performed using a differential thermal analyzer (Diamond DSC manufactured by PerkinElmer).
In the repeated annealing treatment, the measurement sample was held at 220 ° C. for 5 minutes, cooled to 20 ° C. at 10 ° C./min, held for 5 minutes, and then heated to 175 ° C. at 10 ° C./min.
Then, after holding at 175 ° C. for 5 minutes, the mixture was cooled to 20 ° C. at 10 ° C./min, held for 5 minutes, and heated to 170 ° C. at 10 ° C./min.
After that, heating and cooling were repeated so that the maximum heating temperature was sequentially lowered by 5 ° C. At that time, the temperature rising rate was 10 ° C./min, and the minimum temperature was 20 ° C.
The maximum heating temperature was set to 80 ° C., and after holding for 5 minutes, the mixture was cooled to 20 ° C. at 10 ° C./min and held for 5 minutes to complete the repeated annealing treatment.
Then, it was reheated to 200 ° C. at 10 ° C./min, and the final melting curve at that time was analyzed in the same manner as in a normal differential thermal analysis.
In this way, the final melting curve in which the x-axis is the temperature (° C.) and the y-axis is the amount of heat absorbed by melting is obtained, and x ≦ 160 with respect to the total area surrounded by the final melting curve and the baseline. Find the ratio of the area surrounded by the final melting curve at (° C), the baseline, and the straight line at x = 160 (° C), and determine the ratio of melting enthalpy at 160 ° C or lower, that is, the component whose melting temperature is 160 ° C or lower. The ratio was used.
Similarly, the ratio of the area surrounded by the final melting curve at x ≧ 170 (° C.), the baseline, and the straight line at x = 170 (° C.) to the total area is determined, and the ratio of melting enthalpy at 170 ° C. or higher. That is, the ratio of the components having a melting temperature of 170 ° C. or higher was used.

[Rigidity (stiffness)]
The stiffness of the polypropylene sheet was measured according to JIS K7106. Using a stiff nestester (TB-150 manufactured by Taber), measurements were taken at room temperature (23 ° C.) in the pick-up direction (MD) and the vertical direction (TD) thereof, and the average value thereof was calculated. The larger the stiffness value, the better the rigidity.
[Haze]
The haze of the polypropylene sheet was measured according to ISO 14782 using a haze meter (HM-150, manufactured by Murakami Color Technology Laboratory Co., Ltd.). The smaller the haze value, the better the transparency.

[Production Example 1: Preparation of catalyst (S)]
A solid catalyst component was prepared according to the preparation method described in Examples of JP-A-2011-500907. Specifically, it is as follows.
_{250 mL of TiCl 4} was introduced at 0 ° C. into a 500 mL four-necked round bottom flask purged with nitrogen. While stirring, according to the method described in Example 2 of fine spherical MgCl ₂ · 1.8C ₂ H of 10.0g ₅ OH (USP-4,399,054, however operating at 3000rpm instead of 10000rpm production And 9.1 mmol of diethyl-2,3- (diisopropyl) succinate were added. The temperature was raised to 100 ° C. and held for 120 minutes. The stirring was then stopped, the solid product was allowed to settle and the supernatant was sucked out. The following operation was then repeated twice: 250 mL of fresh TiCl ₄ was added, the mixture was reacted at 120 ° C. for 60 minutes and the supernatant was sucked out. The solid was washed 6 times with anhydrous hexane (6 x 100 mL) at 60 ° C. to give a solid catalyst (1).
(Prepolymerization)
The mass ratio of TEAL to the solid catalyst (1) of the solid catalyst (1) obtained above, triethylaluminum (TEAL), and diisopropyldimethoxysilane (DIPMS) is 11, and the mass ratio of TEAL / DIPMS is 11. The contact was carried out at 12 ° C. for 24 minutes in an amount such that the amount was 3. The obtained catalyst system was prepolymerized by holding it in a suspended state in liquid propylene at 20 ° C. for 5 minutes to obtain a catalyst (S).

[Production Example 2: Preparation of catalyst (P)]
Solid catalyst components were prepared by the method described in Example 1 of European Patent No. 674991. The solid catalyst is obtained by supporting Ti and diisobutylphthalate as an internal donor on _{MgCl 2 by the method described in the above patent publication.}
(Prepolymerization)
The amount of the solid catalyst (2) obtained above and TEAL and cyclohexylmethyldimethoxysilane (CHMMS) such that the weight ratio of TEAL to the solid catalyst is 8 and the molar ratio of CHMMS / TEAL is 0.02. Then, they were contacted at −5 ° C. for 5 minutes. The obtained catalyst system was prepolymerized by holding it in a suspended state in liquid propylene at 20 ° C. for 5 minutes to obtain a catalyst (P).

[Polymerization method (G): Multistage polymerization method combining slurry method and gas phase polymerization method]
The first stage used a circulating liquid phase reactor, and the second stage used a fluidized bed vapor phase reactor to perform a multi-stage polymerization method. A catalyst, propylene and hydrogen were supplied to the first stage reactor to produce a propylene homopolymer. Propylene, ethylene and hydrogen were supplied to the second-stage reactor to obtain a polypropylene-based polymer composed of a propylene homopolymer and a propylene / ethylene random copolymer. The polymerization temperature of the first stage was 72 ° C., and the polymerization pressure was 3.0 MPa. The polymerization temperature of the second stage was 80 ° C., and the polymerization pressure was 1.7 MPa.

[Polymerization method (L): Multi-stage polymerization method by slurry method]
Both the first and second stages were subjected to a multi-stage polymerization method using a circulating liquid phase reactor. A catalyst, propylene and hydrogen were supplied to the first stage reactor to produce a propylene homopolymer. Propylene, ethylene and hydrogen were supplied to the second-stage reactor to obtain a polypropylene-based polymer composed of a propylene homopolymer and a propylene / ethylene random copolymer. The polymerization temperature of the first stage was 72 ° C., and the polymerization pressure was 3.0 MPa. The polymerization temperature of the second stage was 66 ° C., and the polymerization pressure was 2.7 MPa.

[Polymerization method (L'): Single-stage polymerization method by slurry method]
The single-stage polymerization method was carried out using a circulating liquid phase reactor. A catalyst, propylene and hydrogen were supplied to the reactor to obtain a propylene homopolymer, and ethylene was further supplied to obtain a propylene / ethylene random copolymer. The polymerization temperature was 72 ° C. and the polymerization pressure was 3.0 MPa.

[Examples 1 to 7, Comparative Examples 1 to 5]
The polymerization step was carried out under the conditions shown in Table 1 to obtain a polypropylene-based polymer.
With respect to 100 parts by mass of the obtained polypropylene-based polymer, as a crystal nucleating agent, a nonitol-based nucleating agent (manufactured by Milliken Japan, product name: Millad NX8000J) or a phosphoric acid ester-based nucleating agent (manufactured by ADEKA, product name: ADEKA STAB NA-21) was added so as to have the content shown in the table, and 0.24 parts by mass of an antioxidant (BASF B225) and 0.05 parts by mass of a neutralizing agent (calcium stearate) were added. The mixture was blended and melt-kneaded at 230 ° C. using an extruder to obtain a polypropylene composition.
The ethylene content, Mw / Mn, xylene insoluble content, xylene insoluble stereoregularity (mm mm) of the polypropylene polymer, the MFR of the polypropylene composition, and the content of the crystal nucleating agent in the obtained polypropylene composition are determined. It is shown in Table 1 (the same applies hereinafter).
In addition, the final melting curve of the polypropylene polymer was analyzed, and the melting peak temperature, the proportion of components having a melting temperature of 170 ° C. or higher, and the proportion of components having a melting temperature of 160 ° C. or lower were measured. The results are shown in Table 1 (the same applies hereinafter).

(Evaluation of sheet)
Using the obtained polypropylene composition, a biaxially stretched sheet was produced as follows.
First, a sheet was produced using a multi-layer sheet molding machine (manufactured by Thermo Plastic Industry Co., Ltd.) equipped with three extruders having a screw diameter of 25 mm and a T-die capable of stacking three layers. More specifically, the polypropylene composition was melted at 230 ° C. using all three extruders. The T-die having a width of 300 mm was set to 230 ° C., and both sides of the sheet were brought into close contact with the peripheral surface of the metal roll to cool the sheet and produce an unstretched sheet having a predetermined thickness.
Using the obtained unstretched sheet, the rigidity and haze of the polypropylene sheet were measured by the above method. These results are shown in Table 1 (the same applies hereinafter).

[Example 8: Manufacture of multilayer sheet]
In sheet molding using the above-mentioned multi-layer sheet molding machine, the surface layer is the material used in Example 1 (MFR = 3 g / 10 minutes), and the intermediate layer is the material used in Example 3 (MFR = 9 g / 10 minutes). An unstretched sheet having a layer ratio of 1: 5: 1 and a thickness of 0.2 mm was produced in two types and three layers by coextrusion. The other steps are the same as in the first embodiment. In Example 8, a material having a high MFR is used only in the intermediate layer as compared with Example 1, but this is an example in which in-process recycling using sheet scraps as recycled materials is assumed in practice.
The rigidity and haze of the polypropylene sheet were measured by the above method. The sheet formability was also evaluated. These results are shown in Table 1 (the same applies hereinafter).

As shown in Table 1, the polypropylene compositions of Examples 1 to 8 had good sheet moldability, low haze, excellent transparency, and excellent rigidity.
Compared with these, Comparative Example 1 in which the amount of xylene insoluble matter, xylene insoluble matter mmmm, and Mw / Mn of the polypropylene-based polymer are small is inferior in sheet rigidity, and Comparative Example 2 consisting of only a propylene / ethylene random copolymer is inferior. In the melting curve by thermal analysis, the condition (B-ii) could not be satisfied, and the rigidity of the sheet was inferior.
Further, in Comparative Example 3 in which the polypropylene-based polymer was made of a propylene homopolymer, the transparency of the sheet was inferior, and in Comparative Example 4 in which the ethylene content in the polypropylene-based polymer exceeded 0.5% by mass, the rigidity of the sheet was inferior. ..
Comparative Example 5 in which the content of the crystal nucleating agent is 0.15 parts by mass is Example 1 in which the content of the crystal nucleating agent is 0.35 parts by mass, or the content of the crystal nucleating agent is 0.25 parts by mass. The rigidity (stiffness) and transparency of the sheet were inferior to those of Example 5.

Claims (4)

It is composed of 30 to 70% by mass of a propylene homopolymer and 30 to 70% by mass of a propylene / ethylene random copolymer, has an ethylene content of 0.5% by mass or less, and has a molecular weight distribution (Mw / Mn) of 6 to 20, 25 ° C. The amount of xylene insoluble matter in the above is 97 to 99% by mass, the stereoregularity (mm mm) of the xylene insoluble matter is 97.5 to 99.5%, and heating and cooling are performed multiple times so that the maximum heating temperature is gradually lowered. A polypropylene polymer whose melting curve by thermal analysis when reheated after repetition satisfies the following conditions (B-i) to (B-iii).
And 0.18 to 0.5 parts by mass of crystal nucleating agent with respect to 100 parts by mass of the polypropylene-based polymer.
A polypropylene composition having a melt flow rate of 1 to 10 g / 10 minutes.
(Bi) The melting peak temperature is 165 ° C. or higher.
(B-ii) The proportion of components having a melting temperature of 170 ° C. or higher is 10% or higher.
(B-iii) The proportion of components having a melting temperature of 160 ° C. or lower is 15% or more. A polypropylene sheet comprising the polypropylene composition according to claim 1. The method for producing the polypropylene composition according to claim 1.
The polypropylene-based polymer is produced by a multi-stage polymerization method having two or more stages of polymerization steps in succession, or by using a polymer having one or both gradients of monomer concentration and polymerization conditions.
A method for producing a polypropylene composition, which comprises mixing the obtained polypropylene-based polymer with the crystal nucleating agent. In the polymerization step, a solid catalyst containing (A) an electron donor compound selected from magnesium, titanium, halogen, and a succinate compound as an essential component; (B) an organoaluminum compound; and (C) an external electron donor. The method for producing a polypropylene composition according to claim 3, wherein a catalyst containing a compound is used.

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