JP7799998B2 - Propylene polymer composition and molded article - Google Patents

Description

The present invention relates to a propylene-based polymer composition having a biomass content of 8.4 to 49% and a molded article thereof. More specifically, the present invention relates to a propylene-based polymer composition that gives a molded article having excellent rigidity and no cracking even when it contains biomass polyethylene. In the present invention, "crackable" means that the composition is broken into several parts when a force is applied. Furthermore, "not crackable" means any of the following:
(1) It does not split into several parts without creating fissures (cracks).
(2) A fissure (crack) forms, but it does not separate into several parts.

Propylene-based resins are characterized by their excellent rigidity, heat resistance, moldability, transparency, and chemical resistance, and are therefore widely used in a variety of applications, including various industrial materials, automobile-related parts, various medical and cosmetic containers, daily necessities, films, and fibers.
Meanwhile, environmental pollution caused by plastics has become a problem in recent years, and how to address this issue is a challenge. One solution is to use carbon-neutral plant-derived plastics (biomass plastics). Plant-derived polypropylene has also been considered, but is not currently on the market. Therefore, the addition of biomass polyethylene to polypropylene has been investigated (see, for example, Patent Documents 1 and 2).

However, the mixture obtained by mixing polypropylene and biomass polyethylene and then melt-kneading it has poor miscibility, and molded articles obtained from this mixture tend to crack. For this reason, there is a demand for polypropylene compositions that have excellent miscibility even when containing biomass polyethylene.

Japanese Patent Application Laid-Open No. 2019-34519 JP 2016-27171 A

In light of the current state of the art, the object of the present invention is to provide a propylene-based polymer composition with a biomass content of 8.4 to 49%, which produces molded articles that are excellent in rigidity and do not crack even when containing biomass polyethylene, and a molded article made from the same.

The present inventors have conducted extensive research and have found a propylene-based polymer composition having a biomass content of 8.4 to 49%, which, when used with a specific propylene-based polymer mixture, gives molded articles that are excellent in rigidity and do not crack even when containing biomass polyethylene, and a molded article thereof, and have completed the present invention.
That is, the present invention provides a propylene-based polymer composition having a biomass content of 8.4 to 49% as follows, and a molded article thereof.

[1] A propylene-based polymer composition containing 51 to 90 parts by weight of a propylene-based (co)polymer (a) satisfying the following conditions (Hi) to (Hv) and 10 to 49 parts by weight of a biomass polyethylene (b) satisfying the following condition (Li), totaling 100 parts by weight, and having a biomass degree of 8.4 to 49%.
(Hi) A metallocene-based propylene homopolymer or a metallocene-based propylene copolymer comprising propylene and an α-olefin content of less than 1% by weight.
(H-ii) The melt flow rate (hereinafter sometimes abbreviated as MFR) according to JIS K7210 (230°C, 2.16 kg load) is in the range of 0.5 to 100 g/10 min.
(H-iii) The melting peak temperature (Tm) is in the range of 135 to 165°C.
(H-iv) The molecular weight distribution (weight average molecular weight/number average molecular weight) is in the range of 1.5 to 4.0.
(Hv) The content of volatile components is 50 ppm by weight or less.
(Li) Low density polyethylene or linear low density polyethylene.
[2] A propylene-based polymer composition containing 0.01 to 0.6 parts by weight of a nucleating agent per 100 parts by weight of the propylene-based polymer composition according to [1].
[3] A molded article obtained using the propylene polymer composition according to [1] or [2].

Molded articles produced using the propylene-based polymer composition of the present invention, which has a biomass content of 8.4 to 49%, are useful because they contribute to reducing environmental impact and provide molded articles that are excellent in rigidity and do not crack, even when containing biomass polyethylene. Injection-molded articles are particularly useful.

FIG. 1 shows a diagram of a crack test in the MD and TD directions, which is carried out by making cuts in an injection test piece of 120 mm×120 mm×2 mm.

The propylene-based polymer composition of the present invention comprises 51 to 90 parts by weight of a propylene-based (co)polymer (a) satisfying the following conditions (Hi) to (Hv) and 10 to 49 parts by weight of a biomass polyethylene (b) satisfying the following condition (Li), totaling 100 parts by weight, and has a biomass degree of 8.4 to 49%, which contributes to reducing environmental load and is characterized by not decreasing performance.
(Hi) A metallocene-based propylene homopolymer or a metallocene-based propylene copolymer comprising propylene and an α-olefin content of less than 1% by weight.
(H-ii) The melt flow rate (MFR) according to JIS K7210 (230°C, 2.16 kg load) is in the range of 0.5 to 100 g/10 min.
(H-iii) The melting peak temperature (Tm) is in the range of 135 to 165°C.
(H-iv) The molecular weight distribution (weight average molecular weight/number average molecular weight) is in the range of 1.5 to 4.0.
(Hv) The content of volatile components is 50 ppm by weight or less.
(Li) Low density polyethylene or linear low density polyethylene.
The propylene polymer composition and molded article of the present invention will be described in detail below.

[1] Components constituting the propylene-based polymer composition (1) Propylene-based (co)polymer (a)

(i) α-Olefin of Propylene-Based (Co)polymer (a) The propylene-based (co)polymer (a) used in the propylene-based polymer composition of the present invention is preferably a metallocene-based propylene homopolymer, a metallocene-based propylene copolymer comprising propylene and an α-olefin in an amount of less than 1% by weight, or a mixture thereof.
From the viewpoint of rigidity, the propylene-based (co)polymer (a) is preferably a homopolymer, and from the viewpoint of transparency, a random copolymer composed of propylene and an α-olefin is desirable. The α-olefin used in the copolymerization includes α-olefins having 2 to 20 carbon atoms excluding propylene, such as ethylene, 1-butene, 1-hexene, and 1-octene. One or more types of α-olefins may be used as copolymerized with propylene. Of these, ethylene and 1-butene are preferred. Ethylene is more preferred. Furthermore, two or more types of these propylene-based polymers may be used in combination. Furthermore, from the viewpoint of rigidity, it is preferable that the α-olefin content is less than 1% by weight.

Specific examples of propylene-based copolymers include binary or ternary copolymers in which small amounts of any comonomer are combined, such as propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, and propylene-1-butene-1-octene copolymer.

The α-olefin content of the propylene (co)polymer (a) is preferably less than 1 wt %, more preferably less than 0.8 wt %, and even more preferably less than 0.5 wt %. When the α-olefin content is less than 1 wt %, the rigidity is improved and there is no risk of deformation when the containers are stacked.
Here, the contents of propylene and α-olefin are values measured by ¹³ C-NMR under the following conditions.
Apparatus: JEOL-GSX270 manufactured by JEOL Ltd.
Concentration: 300mg/2mL
Solvent: orthodichlorobenzene

(ii) Melt flow rate (MFR) of propylene (co)polymer (a)
The propylene (co)polymer (a) used in the present invention has a melt flow rate (MFR) in the range of 0.5 to 100 g/10 min, preferably 5 to 60 g/10 min, and more preferably 10 to 40 g/10 min, according to JIS K7210 (230°C, 2.16 kg load). A melt flow rate (MFR) of 0.5 g/10 min or more improves moldability and produces a satisfactory product. An MFR of 100 g/10 min or less improves mechanical strength.
The melt flow rate (MFR) can be easily adjusted by adjusting the temperature and pressure, which are polymerization conditions for the propylene (co)polymer (a), or by controlling the amount of hydrogen added in a method in which a chain transfer agent such as hydrogen is added during polymerization.

(iii) Stereoregularity of Propylene-Based (Co)polymer (a) When the propylene-based (co)polymer (a) used in the present invention is a propylene homopolymer, the isotactic pentad fraction is preferably 0.90 or more, more preferably 0.94 to 0.98. When the isotactic pentad fraction is 0.90 or more, the rigidity can be satisfactory.
Here, the isotactic pentad fraction is a value measured by the proton decoupling method using ¹³ C-NMR.

(iv) Catalyst for Propylene-Based (Co)polymer (a) The propylene-based (co)polymer (a) used in the present invention is a polymer produced using a metallocene catalyst as a polymerization catalyst. The use of a metallocene catalyst makes the polymer less susceptible to cracking when containing biomass polyethylene (b).

Metallocene-based propylene homopolymers are propylene homopolymers obtained by homopolymerizing propylene using a metallocene catalyst. Metallocene-based propylene copolymers are propylene copolymers obtained by copolymerizing propylene as the main component and ethylene as an α-olefin using a metallocene catalyst.

The metallocene catalyst is preferably a supported type.
A particularly preferred example of the supported metallocene catalyst is an ion-exchanged layered silicate in which the support also functions as a co-catalyst, which is obtained by combining the following components [A], [B], and, if necessary, the following component [C].

Component [A] Metallocene Complex: A transition metal compound of Groups 4 to 6 of the periodic table having at least one conjugated five-membered ring ligand
Component [B] Promoter: Ion-exchange layered silicate
Component [C] organoaluminum compound

Component [A] Metallocene Complex Specifically, the compound represented by the following formula [I] can be used as the component [A].
Q(C ₅ H _4-a R ¹ _a ) (C ₅ H _4-b R ² _b ) MXY...[I]
In formula [I], Q represents a linking group that bridges two conjugated five-membered ring ligands.
M represents a transition metal of Groups 4 to 6 of the periodic table, and among these, titanium, zirconium, and hafnium are preferred.
X and Y each independently represent hydrogen, halogen, a hydrocarbon group having 1 to 20 carbon atoms, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms, or a silicon-containing hydrocarbon group having 1 to 20 carbon atoms.

^R1 and ^R2 each independently represent a hydrocarbon group having 1 to 20 carbon atoms, a halogen, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, an aryloxy group, a silicon-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, a nitrogen-containing hydrocarbon group, or a boron-containing hydrocarbon group. Two adjacent ^R1s or two adjacent ^R2s may be bonded to form a _C4 to _C10 ring. In particular, it is preferable that they form a 6-membered ring or a 7-membered ring, which, together with the conjugated 5-membered ring, form an indene ring or an azulene ring.
a and b are integers satisfying 0≦a≦4 and 0≦b≦4.
Examples of the bonding group Q that bridges two conjugated five-membered ring ligands include an alkylene group, an alkylidene group, a silylene group, and a germylene group. These groups may have hydrogen atoms substituted with alkyl groups, halogens, etc. A silylene group is particularly preferred.

Specific preferred examples of the metallocene complex include the following compounds:
(1) Methylenebis(cyclopentadienyl)zirconium dichloride
(2) Methylene(cyclopentadienyl)(3,4-dimethylcyclopentadienyl)zirconium dichloride
(3) Isopropylidene(cyclopentadienyl)(3,4-dimethylcyclopentadienyl)zirconium dichloride
(4) Ethylene(cyclopentadienyl)(3,5-dimethylpentadienyl)zirconium dichloride
(5) Methylenebis(indenyl)zirconium dichloride
(6) Ethylenebis(2-methylindenyl)zirconium dichloride
(7) Ethylene 1,2-bis(4-phenylindenyl)zirconium dichloride
(8) Ethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride

(9) Dimethylsilylene(cyclopentadienyl)(tetramethylcyclopentadienyl)zirconium dichloride
(10) Dimethylsilylenebis(indenyl)zirconium dichloride
(11) Dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride
(12) Dimethylsilylene(cyclopentadienyl)(fluorenyl)zirconium dichloride
(13) Dimethylsilylene(cyclopentadienyl)(octahydrofluorenyl)zirconium dichloride
(14) Methylphenylsilylenebis[1-(2-methyl-4,5-benzo(indenyl)]zirconium dichloride
(15) Dimethylsilylenebis[1-(2-methyl-4,5-benzoindenyl)]zirconium dichloride
(16) Dimethylsilylenebis[1-(2-methyl-4H-azulenyl)]zirconium dichloride
(17) Dimethylsilylenebis[1-(2-methyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride
(18) Dimethylsilylenebis[1-(2-ethyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride
(19) Dimethylsilylenebis[1-(2-ethyl-4-naphthyl-4H-azulenyl)]zirconium dichloride

(20) Diphenylsilylenebis[1-(2-methyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride
(21) Dimethylsilylenebis[1-(2-methyl-4-(phenylindenyl))]zirconium dichloride
(22) Dimethylsilylenebis[1-(2-ethyl-4-(phenylindenyl))]zirconium dichloride
(23) Dimethylsilylenebis[1-(2-ethyl-4-naphthyl-4H-azulenyl)]zirconium dichloride
(24) Dimethylgermylenebis(indenyl)zirconium dichloride
(25) Dimethylgermylene(cyclopentadienyl)(fluorenyl)zirconium dichloride. Other preferred examples of Group 4, 5, and 6 transition metal compounds, such as titanium compounds and hafnium compounds, are similar to those listed above. These compounds may be used in combination with the catalyst component and catalyst of the present invention.

Component [B] Promoter (ion-exchange layered silicate)
The ion-exchangeable layered silicate is not limited to a naturally occurring one, but may also be an artificially synthesized product. Clay compounds can be used as the ion-exchangeable layered silicate, and specific examples of clay compounds include the following layered silicates described in "Clay Mineralogy" by Haruo Shiramizu, Asakura Shoten (1995):
(A) Kaolin group such as dickite, nacrite, kaolinite, anoxite, metahalloysite, and halloysite, whose main constituent layers are 1:1 type structures, and serpentine group such as chrysotile, lizardite, and antigorite.
(a) Smectite group such as montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stevensite, etc., vermiculite group such as vermiculite, mica group such as mica, illite, sericite, glauconite, attapulgite, sepiolite, palygorskite, bentonite, pyrophyllite, talc, chlorite group, which have a 2:1 type structure as their main constituent layer.

The silicate used in the present invention may be a layered silicate having a mixed layer of the above (a) and (b).
In the present invention, the silicate as the main component is preferably a silicate having a 2:1 type structure, more preferably a smectite group silicate, and particularly preferably montmorillonite.

The activity of these silicates can be improved by chemically treating them with an acid, a salt, an alkali, an oxidizing agent, a reducing agent, an organic solvent, or the like.
The acid treatment removes impurities on the surface of the ion-exchange layered silicate particles, exchanges interlayer cations, and also dissolves some or all of the cations such as Al, Fe, and Mg in the crystal structure.
The acid used in the acid treatment includes hydrochloric acid, nitric acid, sulfuric acid, etc., but inorganic acids are preferred, and sulfuric acid is particularly preferred.
The acid treatment conditions are not particularly limited, but are preferably conditions in which a 5 to 50 wt % aqueous acid solution is reacted at a temperature of 60 to 100°C for 1 to 24 hours, and the acid concentration may be changed during this period. After the acid treatment, washing is usually carried out. Washing is an operation in which the acid contained in the treatment system is separated and removed from the ion-exchanged layered silicate.

The salts used in the salt treatment are preferably selected to contain specific cations, preferably monovalent to tetravalent metal cations, and more preferably Li, Ni, Zn, or Hf cations.
Specific examples of salts include the following:
Examples _of compounds with a Li cation include LiCl, LiBr, _Li2SO4 , _Li3 ( _PO4 ), Li( _ClO4 ), _Li2 ( _C2O4 ), _LiNO3 , _Li ( _OOCCH3 ), and _{Li2 ( C4H4O4 )} .
Examples of those having Ni as a cation include _NiCO3 , Ni( _NO3 ) ₂ , _NiC2O4 , Ni( _ClO4 ) ₂ , _NiSO4 , _NiCl2 , _{and NiBr2} .
Examples of compounds with a Zn cation include Zn( _OOCH3 ) ₂ , Zn( _CH3COCHCOCH3 ) ₂ , _ZnCO3 , Zn( _NO3 ) ₂ , Zn( _ClO4 ) ₂ , _{Zn3 (PO4)2 , ZnSO4 , ZnF2} , ZnCl2, _ZnBr2 , _{and ZnI2} .
Examples of compounds having a cation of Hf include Hf( _OOCCH3 ) ₄ , Hf( _CO3 ) ₂ , Hf( _NO3 ) ₄ , Hf( _SO4 ) ₂ , _HfOCl2 , _HfF4 , _HfCl4 , _HfBr4 , and _HfI4 .

After chemical treatment, the material is dried. Generally, drying temperatures between 100 and 800°C are acceptable, and high temperatures that could cause structural destruction (for example, 800°C or higher, depending on the heating time) are not recommended. Even if the structure is not destroyed, the properties can change depending on the drying temperature, so it is preferable to change the drying temperature depending on the application. Drying times are typically between 1 minute and 24 hours, preferably between 5 minutes and 4 hours, and the atmosphere is dry air, dry nitrogen, dry argon, or under reduced pressure. There are no particular limitations on the drying method, and various methods are possible.

Component [C] Organoaluminum Compound The organoaluminum compound of component [C] is a component that is optionally used as needed, and is most preferably a compound represented by the following formula [II]:
(AlR ⁴ _p X _3-p ) _q ...[II]
In formula [II], ^R4 represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a halogen atom, a hydrogen atom, an alkoxy group, or an amino group, p represents an integer of 1 to 3, and q represents an integer of 1 or 2.
^R4 is preferably an alkyl group, and when X is an alkoxy group, it is preferably an alkoxy group having 1 to 8 carbon atoms, and when X is an amino group, it is preferably an amino group having 1 to 8 carbon atoms.
Of these, preferred are trialkylaluminums where p = 3 and q = 1 and dialkylaluminum hydrides where p = 2 and q = 1. More preferred are trialkylaluminums where R ⁴ has 1 to 8 carbon atoms.

Organoaluminum compounds can be used alone, in combination with other compounds, or in combination. Furthermore, organoaluminum compounds can be added not only during catalyst preparation, but also during prepolymerization or main polymerization.

(v) Method for Producing Propylene-Based (Co)polymer (a) Examples of methods for producing the propylene-based (co)polymer (a) include a slurry polymerization method using an inert solvent in the presence of the catalyst, a solution polymerization method, a gas phase polymerization method using substantially no solvent, and a bulk polymerization method using a polymerization monomer as a solvent.
For example, in the case of a slurry polymerization method, the polymerization can be carried out in an inert hydrocarbon or liquid monomer such as n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, cyclohexane, benzene, toluene, or xylene. The polymerization temperature is usually −80 to 150°C, preferably 40 to 120°C. The polymerization pressure is preferably 1 to 60 atmospheres (0.10 to 6.08 MPa), and the molecular weight of the resulting propylene (co)polymer (a) can be adjusted with hydrogen or other known molecular weight modifiers. The polymerization can be carried out by a continuous or batch reaction, and the conditions may be those typically used. Furthermore, the polymerization reaction may be carried out in one stage or multiple stages.
It is desirable to carry out a prepolymerization treatment before carrying out the main polymerization. As the monomer to be subjected to the prepolymerization, an α-olefin such as ethylene, propylene, 1-butene, or 1-hexene, a diene compound such as 1,3-butadiene, or a vinyl compound such as styrene or divinylbenzene can be used.
This prepolymerization is preferably carried out in an inert solvent under mild conditions, and is desirably carried out so as to produce 0.01 to 1,000 g, preferably 0.1 to 100 g, of polymer per 1 g of solid catalyst (total of component [A] and component [B]).

The polymerization reaction is carried out in the presence or absence of a solvent, such as an inert hydrocarbon such as butane, pentane, hexane, heptane, toluene, or cyclohexane, or a liquefied α-olefin. In the present invention, it is desirable to maximize the amount of polymer produced per solid catalyst (if the solid catalyst has been prepolymerized, this does not include the polymer produced in the prepolymerization). To maximize the amount of polymer produced, it is desirable to set both the polymerization temperature and pressure relatively high.

Typically, the polymerization temperature is selected from 60 to 90°C, and the polymerization pressure is selected from about 1.5 to 4 MPa. In particular, in the case of bulk polymerization, it is preferable that the polymerization temperature is selected from 60 to 80°C, and the polymerization pressure is selected from about 2.5 to 4 MPa in correlation with the temperature. On the other hand, in the case of gas-phase polymerization, it is preferable that the polymerization temperature is selected from 70 to 90°C, and the polymerization pressure is selected from about 1.5 to 4 MPa.
Furthermore, the polymer production amount per solid catalyst can be increased by extending the residence time of the solid catalyst, but an excessively long residence time affects productivity. A preferred residence time is 1 to 8 hours, more preferably 1 to 6 hours. It is desirable to set the polymerization conditions so that the polymer production amount per gram of solid catalyst including the carrier is 20 kg or more, preferably 25 kg or more, more preferably 30 kg or more.
Hydrogen may be present in the polymerization system as a molecular weight modifier. Furthermore, the polymerization may be carried out in multiple stages by changing the polymerization temperature, the concentration of the molecular weight modifier, etc.

In the present invention, after the completion of the polymerization, the obtained propylene (co)polymer (a) is preferably washed with an inert saturated hydrocarbon solvent such as propane, butane, pentane, hexane, or heptane, or a liquid α-olefin, more preferably with an inert hydrocarbon solvent having 3 or 4 carbon atoms or a liquid α-olefin.
The washing method is not particularly limited, and known methods such as decantation of the supernatant after contact treatment in a stirring tank, countercurrent washing, and separation from the washing liquid using a cyclone can be used.
A deactivator may be added before or at the same time as washing. The deactivator is not particularly limited, and examples thereof include water, alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone and methyl ethyl ketone, and mixtures thereof.

(vi) Melting peak temperature (Tm)
The melting peak temperature (Tm) of the propylene (co)polymer (a) used in the present invention is in the range of 135 to 165°C. When the melting peak temperature (Tm) is 135°C or higher, the rigidity and moldability are good, and when it is 165°C or lower, the impact resistance is good. The melting peak temperature (Tm) is preferably 138 to 160°C, more preferably 140 to 155°C.
Specifically, the melting peak temperature (Tm) is measured using a differential scanning calorimeter (DSC). A 5 mg sample is taken, held at 200°C for 5 minutes, crystallized at a temperature drop rate of 10°C/min to 40°C, and then melted at a temperature increase rate of 10°C/min. The peak position of the curve drawn when the sample is heated is taken as the melting peak temperature Tm (°C).
(vii) Molecular weight distribution (Mw/Mn) and weight average molecular weight (Mw) of the propylene (co)polymer (a)
The molecular weight distribution [weight average molecular weight (Mw)/number average molecular weight (Mn)] of the propylene (co)polymer (a) used in the present invention, as determined by gel permeation chromatography (GPC), is in the range of 1.5 to 4.0.
The lower limit of the molecular weight distribution is preferably 1.8 or more, more preferably 2.0 or more, and the upper limit is preferably 3.5 or less, more preferably 3.0 or less.
A lower limit of the molecular weight distribution of 1.5 or more is preferred because it broadens the range of conditions for producing and purifying the propylene (co)polymer (a), thereby improving production efficiency. On the other hand, an upper limit of 4.0 or less indicates that the molecular chain lengths are very uniform, which is preferred because it reduces the content of relatively low molecular weight components such as unreacted monomers, dimers, low molecular weight compounds, amorphous components, and oligomers, which are thought to cause the generation of volatile components.

The weight-average molecular weight (Mw) of the propylene-based (co)polymer (a) used in the present invention is preferably in the range of 100,000 to 600,000. A weight-average molecular weight Mw of 600,000 or less facilitates molding. On the other hand, a weight-average molecular weight Mw of 100,000 or more is practical because it reduces low-crystalline components, suppresses mold contamination, bleed-out, solvent elution, etc., and improves the impact resistance of molded products.

(viii) Average elution temperature (T ₅₀ ) and elution dispersity (σ) of the propylene (co)polymer (a)
The propylene (co)polymer (a) used in the present invention preferably has an average elution temperature (T ₅₀ ) of 90 to 105°C and an elution dispersity (σ) of 9°C or less.
Here, the average elution temperature is a value based on the elution curve of the polymer obtained by temperature rising elution fractionation using o-dichlorobenzene as a solvent, and represents the temperature at which the cumulative mass of the eluted polymer reaches 50% by mass. The elution dispersity is the value of σ when the cumulative mass elution amount I(t) is defined as being expressed by the following mathematical formula (1), assuming that the elution amount obtained by temperature rising elution fractionation follows a normal probability distribution with respect to the elution temperature.

...Equation (1)
Specifically, the dissolution dispersity is σ=T ₅₀ −T _15.9 , where T _15.9 indicates the temperature at which the cumulative mass becomes 15.9 mass %.
By setting the average elution temperature to 90 to 105° C., the molecular weight and melting point of the propylene-based (co)polymer (a) can be made appropriate for molding, thereby improving dimensional accuracy. When the average elution temperature is 90° C. or higher, the molecular weight and melting point of the propylene-based (co)polymer (a) do not become too low, and the dimensional accuracy of the molded product becomes good. When the average elution temperature is 105° C. or lower, the molecular weight and melting point of the propylene-based resin do not become too high, which is preferable.
Furthermore, by having an elution dispersity (σ) of 9° C. or less, it is possible to suppress elution of components due to an increase in temperature and to improve dimensional accuracy. The elution dispersity (σ) is more preferably 7° C. or less, and even more preferably 6° C. or less.
As such a propylene-based (co)polymer (a), commercially available products can be used, such as those available under the trade name WINTEC manufactured by Japan Polypropylene Corporation.

(vx) Volatile Component Content The volatile component content of the propylene (co)polymer (a) used in the present invention is 50 ppm by weight or less. If it is 50 ppm by weight or less, cleanliness is improved and cracking is reduced when the biomass polyethylene (b) is contained. It is preferably 30 ppm by weight or less, and more preferably 20 ppm by weight or less.
The content of volatile components (amount of oligomers having 30 or less carbon atoms) generated from the propylene-based (co)polymer (a) is measured by dynamic headspace (DHS)-GC/MS. The content of volatile components is the ratio of the content of volatile components to the propylene-based (co)polymer (a) (unit: ppm by weight). A specific measurement method is shown below.

(A) Measurement and Evaluation Overview A powder sample of propylene (co)polymer (a) is heated to 100°C, and the volatile components generated are collected at -150°C. Each volatile component is then separated, detected, and identified using a gas chromatograph (GC)/mass spectrometer (MS). A calibration curve is created by preparing a standard mixed solution of aliphatic linear hydrocarbons, in increments of two carbon atoms from 10 to 32, in n-heptane at a concentration of 1000 μg/ml, and measuring under the same conditions as the sample using gas chromatogram/mass spectrometry. Quantitative calculations are performed using n-eicosane as the standard.

(B) Apparatus and measurement method
(A) Heat expulsion (dynamic headspace) device:
Approximately 50 mg of a powder sample of propylene (co)polymer (a) was weighed out and packed into a heated expulsion tube (TDS tube manufactured by GERSTEL), and each end of the tube was filled with approximately 10 mg of quartz wool (GL Sciences, Cat. No. 3001-12404). The TDS tube was then placed in a 40°C heated extraction apparatus (TDS-A manufactured by GERSTEL), the inside of the tube was purged with helium, the temperature was raised to 100°C at a rate of 60°C/min, and the tube was heated at 100°C for 30 minutes. During this heating period, a GC injection port (CIS4 manufactured by GERSTEL) filled with TENAX was cooled to -150°C to collect volatile components generated from the sample. The collected components were vaporized by rapidly heating the collection section to 320°C and introduced into a GC column.
(a) Gas chromatograph (GC):
Agilent HP6890
Column: DB-5ms
Column temperature rise conditions: 40°C x 5 min - 10°C/min - 300°C x 15 min
(c) Mass spectrometer (MS):
Agilent Mass Sensitive Detector 5973N
The components to be measured are ionized by electron impact (EI).

(2) Biomass polyethylene (b)
Plant-derived ethylene, which is a raw material monomer for the biomass polyethylene (b) used in the present invention, can be obtained by fermenting plant materials such as sugarcane with microorganisms to produce ethanol, which is then heated in the presence of a catalyst to cause an intramolecular dehydration reaction.
Biomass polyethylene (b) is a polymer obtained by polymerizing a monomer containing plant-derived ethylene as a main component. The raw material monomer for biomass polyethylene (b) does not have to contain 100% plant-derived ethylene. This is because environmental impact can be reduced by using plant-derived ethylene as part of the monomer.
The biomass polyethylene (b) may be a homopolymer obtained by homopolymerizing plant-derived ethylene or a copolymer obtained by copolymerizing plant-derived ethylene with an α-olefin. The number of carbon atoms in the α-olefin is not particularly limited, but 1-butene, 1-hexene, or 1-octene is preferred. Furthermore, petroleum-derived ethylene may also be contained.

(i) Polyethylene of Biomass Polyethylene (b) Examples of polyethylene used as biomass polyethylene (b) include medium density polyethylene (MDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). These polyethylenes can be used alone or in combination of two or more.
The density of the medium density polyethylene is preferably 0.925 to 0.940 g/cm ³ , and within this range, the rigidity is improved, which is preferable.
Among the above polyethylenes, it is preferable to use at least one of low-density polyethylene and linear low-density polyethylene, as this will provide a sufficient transparency-improving effect.
The density of the low-density polyethylene is preferably 0.910 to 0.920 g/cm ³ , and more preferably 0.913 to 0.917 g/cm ^3. A density of 0.910 g/cm ³ or more is preferred because rigidity is improved, and a density of 0.920 g/cm ³ or less is preferred because transparency improvement effect is sufficient.
The density of the linear low-density polyethylene is preferably 0.895 to 0.925 g/cm ³ , and more preferably 0.900 to 0.917 g/cm ^3. A density of 0.895 g/cm ³ or more is preferred because rigidity is improved, and a density of 0.925 g/cm ³ or less is preferred because transparency improvement effect is sufficient.

The proportion of plant-derived carbon to the total carbon in biomass polyethylene (b) is called the biomass percentage, and can be determined by measuring the concentration of ^14C contained in biomass polyethylene (b). That is, while a certain percentage of ^14C is contained in the atmosphere, the carbon in petroleum-derived resins does not contain ^14C . Therefore, the biomass percentage can be determined by measuring the concentration of ^14C contained in biomass polyethylene (b). Specifically, if all the carbon in biomass polyethylene (b) is petroleum-derived, the biomass percentage is 0%, and if all the carbon in biomass polyethylene (b) is plant-derived, the biomass percentage is 100%. ASTM D6866 is an example of a test method for measuring the ^14C concentration.
The biomass polyethylene (b) preferably has a melt flow rate in the range of 0.21 to 72 g/10 min according to ASTM D1238 (190° C., 2.16 kg load).

The weight proportion of the biomass polyethylene (b) used in the propylene-based polymer composition of the present invention is 10 to 49 parts by weight, preferably 15 to 40 parts by weight. When the amount is 10 parts by weight or more, an environmental load reduction effect can be expected, and when the amount is 49 parts by weight or less, sufficient rigidity of the product can be obtained. (Here, a propylene-based polymer composition containing 51 to 90 parts by weight of the propylene-based (co)polymer (a) and 10 to 49 parts by weight of the biomass polyethylene (b) is 100 parts by weight.)
An example of such biomass polyethylene (b) is "Green PE" (trade name manufactured by Braskem).

(3) Biomass Degree The biomass degree (%) in the present invention is a numerical value calculated by the following formula.
Biomass ratio (%) = [{A × (B ÷ 100)} / C] × 100 Formula (1)
A: Weight of biomass polyethylene (b) B: Bio content (%) of biopolyethylene used
C: Weight of propylene-based polymer composition The bio content (%) of the biomass polyethylene (b) can be measured and calculated according to ASTM D6866.

(4) Nucleating Agent The propylene polymer composition of the present invention may contain a nucleating agent in an amount of preferably 0.01 to 0.6 parts by weight per 100 parts by weight of the propylene polymer composition.
Various common known nucleating agents can be used, such as sterically hindered amide compounds, metal salts of organic dicarboxylic acids, metal salts of organic monocarboxylic acids, sorbitol or its derivatives, nonitol or its derivatives, metal salts of diterpenic acids, or polymer nucleating agents.
Among these, it is particularly preferable to contain a nucleating agent represented by the following formula (1) in order to achieve transparency.

...(1)
(In the formula, n is an integer of 0 to 2; R ¹ to R ⁵ are each independently the same or different and represent hydrogen, halogen, alkyl having 1 to 20 carbon atoms, alkenyl having 2 to 20 carbon atoms, alkoxy having 1 to 20 carbon atoms, alkoxycarbonyl having 1 to 20 carbon atoms, or phenyl; and R ⁶ is alkyl having 1 to 20 carbon atoms.)
Among the nucleating agents represented by formula (1), a representative commercially available product is Milad NX8000J (manufactured by Milliken & Company). Its chemical structural formula is as shown in formula (1-1) below. The molecular weight of this nucleating agent is 484. This substance has the excellent characteristic of being extremely stable thermally and chemically, and therefore hardly undergoing thermal decomposition even at molding temperatures. This is highly preferable because it does not cause the problem of decomposition products bleeding out onto the surface of molded articles and deteriorating their appearance.

... (1-1)

The content of the nucleating agent represented by formula (1) contained in the propylene-based polymer composition of the present invention is preferably in the range of 0.1 to 0.6 parts by weight, more preferably 0.2 to 0.4 parts by weight, and even more preferably 0.3 to 0.4 parts by weight, per 100 parts by weight of the propylene-based polymer composition. When the content of the nucleating agent represented by formula (1) is 0.1 parts by weight or more, rigidity and transparency can be expected to be exhibited, while when it is 0.6 parts by weight or less, there is less concern about bleeding onto the surface of the molded article, which is advantageous in terms of cost-effectiveness (cost performance) in terms of rigidity and transparency, and elution.

(5) Other Additives In addition to the above-mentioned components, the propylene polymer composition of the present invention may contain additives such as various antioxidants used as stabilizers for propylene polymers, ultraviolet absorbers, light stabilizers, and neutralizers.
Specifically, examples of the antioxidant include phosphorus-based antioxidants such as bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, di-stearyl-pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite, and tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4'-biphenylene diphosphonite. antioxidants, phenolic antioxidants such as 2,6-di-t-butyl-p-cresol, tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene and tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, and thio antioxidants such as di-stearyl-β,β'-thio-di-propionate, di-myristyl-β,β'-thio-di-propionate and di-lauryl-β,β'-thio-di-propionate.

Examples of ultraviolet absorbers include 2-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole.

Light stabilizers include n-hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, 2,4-di-t-butylphenyl-3',5'-di-t-butyl-4'-hydroxybenzoate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, dimethyl succinate-2-(4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl)ethanol condensate, poly{[6-[(1,1,3,3-tetramethylbutyl)acetate] Examples of light stabilizers include N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazine condensate.

Further examples include amine-based antioxidants represented by the following formula (2) and formula (3), which have good resistance to NOx gas discoloration, lactone-based antioxidants such as 5,7-di-t-butyl-3-(3,4-di-methyl-phenyl)-3H-benzofuran-2-one, and vitamin E-based antioxidants such as those represented by the following formula (4).

... (2)

...(3)

...(4)

Examples of the neutralizing agent include metal fatty acid salts such as calcium stearate, zinc stearate, and magnesium stearate, hydrotalcite (trade name: DHT-4A, manufactured by Kyowa Chemical Industry Co., Ltd., a magnesium aluminum composite hydroxide salt represented by the following formula (5)), and Mizuka Lack (trade name, manufactured by Mizusawa Industrial Chemicals Co., Ltd., a lithium aluminum composite hydroxide salt represented by the following formula (6)).
Mg _1-x Al _x (OH) ₂ (CO ₃ ) _x/2・mH ₂ O…(5)
[In the formula, x is 0<x≦0.5, and m is a number of 3 or less.]
[ _Al2Li (OH) ₆ ] _nX・_mH2O ...(6)
[In the formula, X is an inorganic or organic anion, n is the valence of the anion (X), and m is 3 or less.]

In addition, various known additives, such as antistatic agents, lubricants, dispersants such as fatty acid metal salts, dyes, pigments, etc., can be added as long as they do not impair the objectives of the present invention.

Within the scope of the present invention, within the limits of not impairing the properties, functions, and other characteristics of the propylene-based polymer composition, 1 to 30 parts by weight of other polymers besides the propylene-based (co)polymer (a) and biopolyethylene (b), such as mono-, bi-, or terpolymers such as polyethylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-1-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, and acrylate polymer, can be added per 100 parts by weight of the propylene-based polymer composition. Similarly, it is also possible to blend elastomers such as natural rubber, butyl rubber, diene rubber, EPR, and EPDM. Furthermore, it is also possible to use general-purpose inorganic fillers such as talc, calcium carbonate, silica, alumina, gypsum, and mica in combination.

(6) Flexural Modulus of Propylene-Based Polymer Composition The flexural modulus of the propylene-based polymer composition used in the present invention is preferably in the range of 800 to 1500 MPa. When the flexural modulus is 800 MPa or more, the rigidity required to maintain the product characteristics and shape is obtained, and when it is 1500 MPa or less, the impact resistance is good. The flexural modulus is more preferably 1000 to 1500 MPa, still more preferably 1100 to 1450 MPa, and particularly preferably 1200 to 1400 MPa.

(7) Charpy Impact Strength of Propylene-Based Polymer Composition The Charpy impact strength of the propylene-based polymer composition used in the present invention is preferably 3.0 kJ/ ^m2 or more. When the Charpy impact strength is 3.0 kJ/ ^m2 or more, breakage of a molded article during transportation is suppressed. The Charpy impact strength is more preferably 3.5 kJ/ ^m2 or more, and even more preferably 4.0 kJ/ ^m2 or more.

(8) Haze of Propylene-Based Polymer Composition The haze of the propylene-based polymer composition used in the present invention at a product thickness of 2 mmt is preferably in the range of 50% or less. When the haze is 50% or less, the visibility of the contents improves and the design becomes better. The haze is more preferably 45% or less, and even more preferably 35% or less.

[2] Method for producing propylene-based polymer composition The propylene-based polymer composition of the present invention can be obtained by mixing predetermined amounts of the propylene-based (co)polymer (a), the biomass polyethylene (b), and, if necessary, other additives in a Henschel mixer (trade name), a super mixer, a ribbon blender, or the like, and then melt-kneading the mixture in a temperature range of 190 to 260°C using a conventional single-screw extruder, a twin-screw extruder, a Banbury mixer, a plavender, a roll, or the like.

[3] Molded Article Obtained Using Propylene-Based Polymer Composition To produce a molded article using the propylene-based polymer composition of the present invention, the propylene-based polymer composition is molded into a molded article having a desired shape by injection molding or the like.
The uses of the molded articles are not particularly limited, but they can be used in a wide variety of applications, such as various industrial materials, automobile-related parts, various containers for medical and cosmetic use, daily necessities, films and fibers.

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.
In the following examples and comparative examples, the physical properties of the propylene (co)polymer (a) and the propylene polymer composition were measured according to the following methods.
<1. Measurement method>

(1) Melt flow rate (MFR):
Measurement was carried out in accordance with JIS K7210 (230°C, 2.16 kg load).

(2) Calculation of the ethylene content of the propylene (co)polymer (a)
The ethylene content in the random copolymer was measured by infrared spectroscopy using a characteristic absorption band at 733 cm ^-1 , using an ethylene-propylene random copolymer whose composition had been verified by ^C -NMR as a standard material. The pellets were press-molded into a film with a thickness of approximately 500 μm.

(3) Measurement of molecular weight and molecular weight distribution:
The molecular weight distribution Mw/Mn of the propylene-based (co)polymer (a) was calculated by measuring the weight average molecular weight Mw and the number average molecular weight Mn by gel permeation chromatography (GPC) under the following conditions:
Apparatus: GPC (ALC/GPC 150C) manufactured by WATERS
Detector: FOXBORO MIRAN 1A IR detector (measurement wavelength: 3.42 μm)
Column: Showa Denko AD806M/S (3 columns in series)
Mobile phase solvent: o-dichlorobenzene Measurement temperature: 140°C
Flow rate: 1.0ml/min Injection volume: 0.2ml

(4) Melting peak temperature (melting point) (Tm, unit: ° C.):
Using a differential scanning calorimeter (DSC), a 5.0 mg sample was taken, the temperature was raised to 200°C once to erase the thermal history, and then the sample was held at 200°C for 5 minutes. The temperature was then lowered to 40°C at a rate of 10°C/min to crystallize the sample, and the temperature was then raised again at a rate of 10°C/min to melt the sample. The temperature at the top of the endothermic peak was taken as the melting peak temperature (melting point) (Tm).

(5) Volatile Component Content The volatile component content (amount of oligomers having 30 or less carbon atoms) generated from the propylene (co)polymer (a) was measured by dynamic headspace (DHS)-GC/MS. The volatile component content is the ratio of the amount of volatile components generated to the propylene polymer (a) (unit: ppm by weight). The measurement method is shown below.

(A) Measurement and Evaluation Overview A powder sample of propylene (co)polymer (a) was heated to 100°C, and the volatile components generated were collected at -150°C. Each volatile component was then separated, detected, and identified using a gas chromatograph (GC)/mass spectrometer (MS). A calibration curve was created by preparing a standard mixed solution of aliphatic linear hydrocarbons, in increments of two carbon atoms from 10 to 32, in n-heptane at a concentration of 1000 μg/ml, and measuring the solution under the same conditions as the sample using gas chromatogram/mass spectrometry. Quantitative calculations were performed using n-eicosane as the standard.

(B) Apparatus and Measurement Method (A) Heat Purging (Dynamic Headspace) Apparatus:
Approximately 50 mg of a powder sample of propylene-based (co)polymer (a) was weighed out and packed into a heated expulsion tube (TDS tube manufactured by GERSTEL), and both ends were filled with approximately 10 mg of quartz wool (GL Sciences, Cat. No. 3001-12404). The TDS tube was then placed in a 40°C heated extraction apparatus (TDS-A manufactured by GERSTEL), the inside of the tube was purged with helium, the temperature was raised to 100°C at a rate of 60°C/min, and the tube was heated at 100°C for 30 minutes. During this heating period, a GC injection port (CIS4 manufactured by GERSTEL) filled with TENAX was cooled to -150°C to collect volatile components evolved from the sample. The collected components were vaporized by rapidly heating the collection section to 320°C and introduced into a GC column.
(a) Gas chromatograph (GC):
Agilent HP6890
Column: DB-5ms
Column temperature rise conditions: 40°C x 5 min - 10°C/min - 300°C x 15 min
(c) Mass spectrometer (MS):
Agilent Mass Sensitive Detector 5973N
The components to be measured were ionized by electron impact (EI).

(6) Flexural Modulus: Measured in accordance with JIS K7171.

(7) Charpy Impact Strength Charpy impact strength at 23°C was measured in accordance with JIS K7111.
(8) Haze Value: Measured in accordance with JIS K7136 using a sheet piece having a thickness of 2 mm.

(9) Crack test in MD and TD directions Test pieces of 120 mm x 120 mm x 2 mm were injection molded (molding temperature: 200°C, mold temperature: 40°C), and a cut of about 3 cm in length was made in each piece with pruning shears so that the cut was 1.5 cm wide, as shown in Figure 1. The cut part was then bent by hand, and the cracking was evaluated according to the following criteria.
◎: No splits (fissures, cracks) or separation into several pieces even when bent more than 90 degrees (no splits)
○: Even when bent more than 90 degrees, a split (crack) occurs, but the film does not separate into several parts (does not split).
×: When bent more than 90 degrees, it separates into several parts (cracks).

<2. Resins and Additives>
2-1. Production of propylene (co)polymer (a) (1) Production Example 1
(i) Preparation of Catalyst The following operations were carried out under an inert gas atmosphere using deoxygenated and dehydrated solvents and monomers.
(ii) Chemical Treatment of Ion-Exchanged Layered Silicate Acid Treatment: 1,130 g of distilled water and 750 g of 96% sulfuric acid were placed in a separable flask, and the internal temperature was maintained at 90°C. 300 g of granulated smectite (Benclay SL, manufactured by Mizusawa Chemical Industries, Ltd.) having an average particle size of 25 μm was added thereto, and the mixture was allowed to react for 5 hours.
Washing: The solid was cooled to room temperature in 1 hour and washed with distilled water until the pH reached 3.69. The washing ratio was 1/10,000 or less (volume ratio). The solid at this stage was partially dried, and the elution rate by acid treatment was determined to be 33.5% by weight.
Salt treatment: 211 g of lithium sulfate monohydrate was dissolved in 521 g of distilled water, and 100 g (dry weight) of the solid obtained by the acid treatment was added thereto. The mixture was stirred at room temperature for 120 minutes. The resulting slurry was filtered, and 3,000 g of distilled water was added to the resulting solid, followed by stirring at room temperature for 5 minutes. The slurry was then filtered again. 2,500 g of distilled water was added to the resulting solid, and the solid was stirred for 5 minutes and filtered again. This procedure was repeated four more times. The resulting solid was pre-dried at 130°C for 2 days under a nitrogen stream, after which coarse particles of 53 μm or larger were removed. The solid was then further dried under reduced pressure at 200°C for 2 hours to obtain chemically treated smectite.
(iii) Silicate Activation Treatment 200 g of the above-mentioned chemically treated smectite was introduced into a 3 L glass reactor equipped with a stirring blade, and 750 ml of normal heptane and a heptane solution (500 mmol) of tri-normal octylaluminum were added thereto, followed by stirring at room temperature. After 1 hour, the mixture was washed with normal heptane (residual liquid rate less than 1%) (weight ratio of heptane to solid component) to adjust the slurry volume to 2000 mL.

(iv) Preparation of Prepolymerized Catalyst Next, 870 mL of a toluene slurry containing 3 mmol of (r)-dimethylsilylenebis[2-methyl-4-(4-chlorophenyl)-4H-azulenyl]zirconium dichloride and 42.6 mL of a heptane solution of triisobutylaluminum (15 mmol) were reacted at room temperature for 1 hour. The reaction mixture was added to the above-mentioned chemically treated smectite slurry and stirred for 1 hour. Subsequently, 2.1 L of normal heptane was introduced into a 10 L stirred autoclave that had been thoroughly purged with nitrogen and maintained at 40°C. The previously prepared montmorillonite/complex slurry was then introduced. Once the temperature stabilized at 40°C, propylene was fed at a rate of 100 g/hour, and the temperature was maintained. After 4 hours, the propylene feed was stopped, and the temperature was maintained for an additional 2 hours. About 3 L of the supernatant was removed from the recovered prepolymerized catalyst slurry, and 170 mL of a heptane solution of triisobutylaluminum (30 mmol) was added, followed by stirring for 10 minutes and heat treatment under reduced pressure at 40° C. This operation yielded a prepolymerized catalyst containing 2.30 g of polypropylene per 1 g of catalyst.

(V) Production of Propylene-Based Polymer Continuous production of a propylene-ethylene copolymer was carried out by a process incorporating a liquid-phase polymerization tank with an internal volume of 270 L equipped with a stirrer, a deactivation tank with an internal volume of 400 L, a deactivation and washing system consisting of a slurry circulating pump, a circulation line liquid classifier, a concentrator, a countercurrent pump and a washing liquid receiving tank, a high-pressure degassing system consisting of a double-pipe heat exchanger and a fluidized flash tank, and a post-treatment system including a low-pressure degassing tank and a dryer.
The prepolymerized catalyst prepared above was dispersed in liquid paraffin (manufactured by Tonen K.K. under the trade name "Whitelex 335") at a concentration of 15 wt% (relative to a total of 100 wt. parts of 15 wt. parts of prepolymerized catalyst and 85 wt. parts of liquid paraffin), and the resulting dispersion was introduced as a catalyst component into a liquid-phase polymerization vessel at a rate of 0.35 g/hr. Furthermore, liquid propylene was continuously fed into the polymerization vessel at a rate of 40 kg/hr, ethylene at a rate of 0.4 kg/hr, hydrogen at a rate of 0.25 g/hr, and triisobutylaluminum at a rate of 18 g/hr. Polymerization was carried out while maintaining the temperature inside the vessel at 70°C. A mixed slurry of polymer and liquid propylene was extracted from the liquid-phase polymerization vessel into a deactivation washing vessel at a rate of 12.0 kg/hr as polymer. The average residence time of the catalyst in the polymerization vessel was 1.3 hours. Ethanol was fed as a deactivator into the deactivation washing vessel at a rate of 21.0 g/hr. Liquid propylene was further supplied at 40 kg/hr, and the temperature inside the tank was maintained at 50°C by heating with a jacket. The polymer was extracted from the bottom of the classifier into a high-pressure degassing tank, then passed through a low-pressure degassing tank, and then dried in a dryer. The temperature inside the dryer was adjusted to 80°C and the residence time to 1 hour, and dry nitrogen at room temperature was flowed at a flow rate of 12 ^m3 /hr in the countercurrent direction to the powder flow. The dried polymer was removed from the hopper.
On the other hand, the liquid propylene separated from the polymer through the classifier and the concentrator was discharged into a washing liquid receiving tank at a rate of 40 kg/hr. The yield of the obtained polymer per gram of solid catalyst was 34.3 kg, the ethylene content was 0.8 wt%, MFR was 31 g/10 min, molecular weight distribution (Mw/Mn) was 2.4, Tm was 142°C, and the volatile component content was 5 ppm by weight.

(vi) Granulation: 100 parts by weight of the propylene-ethylene copolymer powder was blended with 0.03 parts by weight of a phenolic antioxidant, tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane (trade name: IRGANOX 1010, manufactured by BASF Japan Ltd.), and the mixture was mixed at room temperature for 3 minutes using a high-speed stirring mixer (trade name: Henschel Mixer), followed by melt-kneading in a nitrogen atmosphere using a twin-screw extruder to obtain pellets of the propylene-ethylene copolymer. The twin-screw extruder used was a KZW-25 manufactured by Technovel Co., Ltd., with a screw rotation speed of 400 RPM and kneading temperatures set at 80, 160, 210, and 230°C from the bottom of the hopper (hereafter, the same temperature from the die outlet).

(2) Production Example 2
(i) Synthesis of Complex 1 (Synthesis Example 1: Preparation of Component [A-1] (Complex 1))
Component [A-1] (Complex 1) was synthesized using rac-dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-i-propylphenyl)indenyl}]hafnium according to the method described in Synthesis Example 1 of JP-A 2012-149160.
(ii) Synthesis of Complex 2 (Synthesis Example 2: Preparation of Component [A-2] (Complex 2))
As component [A-2] (complex 2), rac-dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium was synthesized according to the method described in Example 7 of JP-A No. 11-240909.

(iii) Preparation of Catalyst (iii-1) Chemical Treatment of Layered Silicate 645.1 g of distilled water and 82.6 g of 98% sulfuric acid were added to a 1 L three-neck flask equipped with a stirring blade and a reflux device, and the mixture was heated to 95 ° C. 100 g of commercially available montmorillonite (manufactured by Mizusawa Industrial Chemicals, Ltd. under the trade name Benclay KK, Al = 9.78 wt%, Si = 31.79 wt%, Mg = 3.18 wt%, Al/Si (atomic ratio) = 0.320, average particle size 14 μm) was added, and the mixture was reacted at 95 ° C. for 320 minutes. After 320 minutes, 0.5 L of distilled water was added to stop the reaction, and 255 g of a cake-like solid was obtained by filtration.
1,545 g of distilled water was added to this cake to form a slurry, and the temperature was raised to 40° C. 5.734 g of lithium hydroxide monohydrate was added as a solid, and the mixture was reacted for 1 hour at 40° C. After 1 hour, the reaction slurry was filtered and washed three times with 1 L of distilled water, again yielding a cake-like solid.
The recovered cake was dried to obtain 80 g of chemically treated montmorillonite, which had a chemical composition of Al = 7.68 wt%, Si = 36.05 wt%, Mg = 2.13 wt%, Al/Si (atomic ratio) = 0.222, and Li = 0.53 wt%.

(iii-2) Preparation of propylene polymerization catalyst 150 kg of the chemically treated montmorillonite obtained as in (iii-1) above was placed in a reactor having an internal volume of ¹ m3, and 2,832 L of hexane was added to form a slurry, to which 74.4 kg (375 mol) of triisobutylaluminum was added over 85 minutes and stirred for 60 minutes. Thereafter, the mixture was washed with hexane by decantation until the washing ratio reached 1/32, and the total volume (amount of slurry) was adjusted to 900 L.
The slurry solution containing the chemically treated montmorillonite was kept at 50° C., and 0.65 kg of triisobutylaluminum (3.28 mol, 4.257 kg as a hexane solution with a concentration of 15.3 wt %) was added thereto.
After stirring for 5 minutes, 0.657 kg (0.81 mol) of rac-dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4-hydroazulenyl}]hafnium and 96 L of toluene were added, and stirring was continued for 60 minutes.
Thereafter, 9.758 kg (26.61 mol) of tri-normal-octylaluminum was added and stirred for 6 minutes, and then a separately prepared solution, that is, a solution prepared by adding 1.768 kg (1.89 mol) of rac-dichloro[1,1'-dimethylsilylenebis{2-(5-methyl-2-furyl)-4-(4-i-propylphenyl)indenyl}]hafnium to 0.064 kg of triisobutylaluminum (9.88 kg, 0.32 mol of a toluene solution with a concentration of 0.648 wt %) in 240 L of toluene in a separate vessel equipped with a stirrer, was added, and 100 L of toluene was added, and stirring was continued for a further 20 minutes.
Thereafter, 2387 L of hexane was added, the internal temperature of the reactor was raised to 40°C, and then 328.1 kg of propylene was fed over 240 minutes to carry out prepolymerization while maintaining the temperature at 40°C.
Thereafter, the propylene feed was stopped, and the residual polymerization was carried out at 40° C. for 80 minutes.
After completion of the residual polymerization, stirring was stopped, and the contents were allowed to settle and settle. The supernatant was removed so that the solution volume became 1500 L, and 12.7 kg of triisobutylaluminum was added, and 3974 L of hexane was added again, and after stirring, the contents were allowed to settle and settle, and the supernatant was removed so that the solution volume became 1500 L.
To this was added 8.9 kg of triisobutylaluminum (42.9 kg of a hexane solution with a concentration of 20.8% by weight) and 205 L of hexane.
The reaction mixture was then transferred to a dryer and dried at 40°C for 9 hours to obtain 465 kg of a prepolymerized catalyst (prepolymerized catalyst 1). The prepolymerization ratio (the value obtained by dividing the amount of the prepolymerized polymer by the amount of the solid catalyst) was 2.10.

(iv) Production of Propylene Polymer Liquefied propylene was continuously introduced into a 100 ^m3 stirred high-pressure reactor (L/D = 1.2) at flow rates of 20 T/hr, triisobutylaluminum at 80 kg/hr, hydrogen at 0.180 kg/hr, and prepolymerization catalyst 1 at 0.87 kg/hr (weight excluding prepolymer), and continuous polymerization was carried out while maintaining the temperature at 70±0.1°C and the polymer slurry concentration in the polymerization reactor at 40 wt%. The production rate of propylene homopolymer (powder) was 8.0 T/hr.
The obtained propylene homopolymer (powder) was thoroughly dried and then analyzed using the powder, and the results were as follows: ethylene content = 0 wt %, MFR = 33 g/10 min, molecular weight distribution (Mw/Mn) = 3.2, Tm = 154°C, and volatile component content = 5 ppm by weight.
The powder was granulated under the following granulation conditions to obtain pellets of propylene homopolymer.

(v) Granulation: 100 parts by weight of the propylene homopolymer powder were blended with 0.125 parts by weight of tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane (trade name: IRGANOX 1010, manufactured by BASF Japan Ltd.), which is a phenol-based antioxidant, and 0.125 parts by weight of tris(2,4-di-t-butylphenyl)phosphite (trade name: IRGAFOS 168, manufactured by BASF Japan Ltd.), which is a phosphite-based antioxidant. The mixture was mixed at room temperature for 3 minutes using a high-speed stirring mixer (trade name: Henschel mixer), and then melt-kneaded in a nitrogen atmosphere using a twin-screw extruder to obtain pellets of the propylene homopolymer. The twin-screw extruder used was a KZW-25 manufactured by Technobel Co., Ltd. The screw rotation speed was 400 RPM, and the kneading temperatures were set at 80, 160, 210, and 230°C from the bottom of the hopper (the same temperature was maintained from then until the die exit).

2-2. Production of propylene-based (co)polymers other than propylene-based (co)polymer (a) (1) Production Example 3
(i) Preparation of solid catalyst A 100-liter reactor equipped with a stirring blade, thermometer, jacket, and cooling coil was charged with 30 mol of Mg(OEt) ₂ , and then Ti(OBu) ₄ was charged so that the ratio of Ti(OBu) ₄ /Mg was 0.60 (m.r. (molar ratio)) relative to the magnesium in the charged Mg(OEt) _2. Furthermore, 19.2 kg of toluene (TOL) was charged, and the temperature was raised while stirring. After reacting at 139°C for 3 hours, the temperature was lowered to 130°C, and a toluene solution of MeSi(OPh) ₃ was added so that the ratio of MeSi(OPh) ₃ /Mg was 0.67 (m.r.) relative to the magnesium in the charged Mg(OEt) _2. The amount of toluene used here was 7.8 kg. After the addition was completed, the mixture was reacted at 130°C for 2 hours, then cooled to room temperature, and Si(OEt) ₄ was added. The amount of Si(OEt) ₄ added was adjusted so that the ratio of Si(OEt) ₄ /Mg was 0.056 (m.r.) relative to the magnesium in the Mg(OEt) ₂ previously charged.

Next, toluene was added to the resulting reaction mixture so that the magnesium concentration became 0.58 (mol/L-TOL). Furthermore, diethyl phthalate (DEP) was added so that the DEP/Mg ratio was 0.10 (m.r.) relative to the magnesium in the Mg(OEt) ₂ previously charged. The resulting reaction mixture was cooled to 10°C while continuing to stir, and TiCl ₄ was added dropwise over 2 hours to obtain a homogeneous solution. Note that TiCl ₄ was added so that the TiCl ₄ /Mg ratio was 4.0 (m.r.) relative to the magnesium in the Mg(OEt) ₂ previously charged. After the TiCl ₄ addition was completed, the mixture was heated to 15°C at 0.5°C/min while stirring and maintained at the same temperature for 1 hour. Next, the mixture was heated again to 50°C at 0.5°C/min and maintained at the same temperature for 1 hour. The mixture was then heated to 118°C at 1°C/min and maintained at the same temperature for 1 hour. After the treatment was completed, stirring was stopped, the supernatant liquid was removed, and the residue was washed with toluene to a residual liquid ratio of 1/73 (volume ratio of toluene/solid component) to obtain a slurry of the solid component.

Next, toluene and _TiCl4 were added to the slurry obtained here at room temperature. The _TiCl4 was adjusted so that _TiCl4 /Mg(OEt) ₂ = 5.0 (m.r.) relative to the magnesium in the Mg(OEt) ₂ that had been charged earlier. The toluene was also adjusted so that the _TiCl4 concentration was 2.0 (mol/L-TOL). The slurry was heated with stirring, and the reaction was carried out at 118°C for 1 hour. After the reaction was completed, the stirring was stopped, the supernatant liquid was removed, and the mixture was washed with toluene so that the residual liquid ratio was 1/150 (volume ratio of toluene/solid component), and a slurry of the solid component was obtained.

(ii) Preparation of Solid Catalyst Component (A) 400 g of the solid component obtained in (i) was transferred to another reactor equipped with a stirring blade, a thermometer, and a cooling jacket, and normal hexane was added to dilute the solid component to a concentration of 5.0 (g/L). While stirring the resulting slurry, trimethylvinylsilane, TEA, and TBMDES were added at 15°C. TEA represents triethylaluminum, TBMDES represents t-butylmethyldiethoxysilane, and t-butyl represents a tertiary butyl group. The amounts of TEA, trimethylvinylsilane, and TBMDES added were 0.475 g, 0.137 g, and 0.167 g, respectively, per gram of the solid component in the solid catalyst component (A). After the addition was completed, the mixture was maintained at 15°C for 1 hour while continuing to stir, and then the temperature was raised to 30°C and stirred at the same temperature for 2 hours. Next, the temperature was lowered again to 15°C, and while maintaining the same temperature, 4.8 kg of propylene gas was fed at a constant rate into the gas phase of the reactor over 8 hours to carry out prepolymerization. After the feed was completed, stirring was stopped, the supernatant liquid was removed, and the mixture was washed with normal hexane to obtain a slurry of solid catalyst component (A). The residual liquid rate was 1/12 (volume ratio of normal hexane/solid catalyst component (A)). The obtained solid catalyst component (A) had 12.0 g of propylene polymer per 1 g of solid catalyst component (A).

(iii) Production of Propylene-Ethylene Copolymer Continuous production of propylene-ethylene copolymer was carried out using a process incorporating a degassing system consisting of a double-pipe heat exchanger and a fluidized flash tank downstream of a 0.4 ^m3 liquid-phase polymerization vessel equipped with an agitator. Liquefied propylene, ethylene, hydrogen, TEA, and TBEDMS were continuously fed into the liquid-phase polymerization vessel. TBEDMS represents t-butylethyldimethoxysilane, and t-butyl represents a tertiary butyl group. The feed rates of liquefied propylene, TEA, and TBEDMS were 163 kg/hr, 8.86 g/hr, and 1.37 g/hr, respectively. Hydrogen and ethylene were fed to a gas-phase concentration of 6.15 mol% and 0.74 mol%, respectively. Furthermore, the solid catalyst component (A) obtained in (ii) above was fed so that the solid component contained in (A) was 0.13 g/hr. The liquid-phase polymerization vessel was cooled so that the polymerization temperature was 70°C. The slurry polymerized in this liquid-phase polymerization vessel was heated by a double-pipe heat exchanger and discharged into a fluidized flash vessel. The discharge rate of the slurry was adjusted so that the propylene-ethylene copolymer particles contained in the slurry were approximately 24 kg/hr. The average residence time of the propylene-ethylene copolymer particles in the liquid-phase polymerization vessel was 1.4 hours. Analysis of the discharged propylene-ethylene copolymer revealed that the MFR was 25.0 g/10 min, the ethylene content was 0.7 wt%, the molecular weight distribution (Mw/Mn) was 5.6, the Tm was 156°C, and the volatile component content was 130 ppm by weight.

(iv) Granulation 100 parts by weight of the propylene-ethylene copolymer powder were blended with 0.03 part by weight of tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane (trade name: IRGANOX 1010, manufactured by BASF Japan Ltd.), which is a phenol-based antioxidant, 0.03 part by weight of tris(2,4-di-t-butylphenyl)phosphite (trade name: IRGAFOS 168, manufactured by BASF Japan Ltd.), which is a phosphite-based antioxidant, and 0.05 part by weight of calcium stearate "CAST" (manufactured by NOF Corporation), which is a neutralizing agent, and the mixture was mixed at room temperature for 3 minutes using a high-speed stirring mixer (trade name: Henschel mixer), and then melt-kneaded in a nitrogen atmosphere using a twin-screw extruder to obtain pellets of the propylene-ethylene copolymer. The twin-screw extruder used was a KZW-25 manufactured by Technobel Co., Ltd. The screw rotation speed was 400 RPM, and the kneading temperatures were set at 80, 160, 210, and 230°C from the bottom of the hopper (the same temperature was maintained from then until the die exit).

2-3. Propylene (co)polymer (a)
(PP-1) Propylene-based resin obtained by polymerization in Production Example 1 (PP-2) Propylene-based resin obtained by polymerization in Production Example 2 2-4. Propylene-based (co)polymer other than propylene-based (co)polymer (a) (PP-3) Propylene-based resin obtained by polymerization in Production Example 3

2-5. Biomass polyethylene (b)
Low-density polyethylene (LDPE)
(PE-1) Product name “Green PE SPB608” manufactured by Braskem
Density: 0.915 g/cm ³ , melt flow rate according to ASTM D1238 (190°C, 2.16 kg load) is 30 g/10 min, bio content: 95% (all properties are listed in the manufacturer's catalogue).
Linear low density polyethylene (LLDPE)
(PE-2) Product name “Green PE SLL118” manufactured by Braskem
Density: 0.916 g/cm ³ , melt flow rate according to ASTM D1238 (190°C, 2.16 kg load) is 1 g/10 min, bio content: 87% (all properties are listed in the manufacturer's catalogue).
2-6. Biomass polyethylene other than biomass polyethylene (b) High density polyethylene (HDPE)
(PE-3) Braskem product name “Green PE SGM9450F”
Density: 0.952 g/cm ³ , melt flow rate according to ASTM D1238 (190°C, 5 kg load) is 0.33 g/10 min, bio content: 96% (all properties are listed in the manufacturer's catalogue).

2-6. Other Additives (A-1) Hindered phenol-based antioxidant "IR1010"tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxylphenyl)propionate]methane, manufactured by BASF Japan Ltd., trade name "IRGANOX1010".
(A-2) Phosphorus-based antioxidant "IF168" tris(2,4-di-t-butylphenyl)phosphite, manufactured by BASF Japan Ltd., trade name "IRGAFOS168".
(B-1) Neutralizer "CAST" calcium stearate, manufactured by NOF Corporation.
(N-1) Nucleating agent "NX8000J" 1,2,3-trideoxy-4,6:5,7-bis-[(4-propylphenyl)methylene]-nonitol, manufactured by Milliken & Company, trade name "Milad NX8000J".

3. Examples 1 to 7 and Comparative Examples 1 to 9
Each polymer (pellet) and additive were prepared in the blending ratio (parts by weight) shown in Table 1, dry-blended in a super mixer, and then melt-kneaded and pelletized in a nitrogen atmosphere at a die outlet temperature of 220°C using a TEM-35B twin-screw extruder manufactured by Toshiba Machine Co., Ltd. The resulting pellets were used to measure physical properties. The evaluation results are shown in Table 1.

As is clear from Table 1, Examples 1 to 7 contain the specified amounts of the propylene-based (co)polymer (a) and biomass polyethylene (b) according to the present invention, and are materials that can reduce environmental impact, have excellent rigidity, and are not prone to cracking. Example 1 contains a specified amount of LDPE as the biomass polyethylene (b), and is also found to be excellent in transparency. Example 2 has the same composition as Example 1, but the content of biomass polyethylene (b) LDPE is increased, and it is found that the impact strength is improved while the biomass content is increased, making it excellent from the perspective of environmental impact. Example 3 has the same composition as Example 1, but the content of biomass polyethylene (b) LDPE is reduced, and it is found to be even more excellent in rigidity and transparency than Example 1. Example 4 uses LLDPE as the biomass polyethylene (b), and although the content is the same as Example 1, both rigidity and impact strength are further improved from Example 1. In Examples 5 and 6, propylene homopolymer was used as the propylene-based (co)polymer (a), but by including LDPE or LLDPE as the biomass polyethylene (b), the high rigidity derived from the propylene homopolymer was maintained, and the impact strength was also high, preventing breakage, confirming the effect of the present invention. Example 7 has the same composition as Example 1 but does not include a nucleating agent, and although the rigidity and transparency are lower than in Example 1 which contains a nucleating agent, it is clear that the rigidity required for use as a product is still maintained.
On the other hand, Comparative Examples 1 and 2 have sufficient crack resistance, but the content of biomass polyethylene (b) LDPE is low, and they do not have a sufficient biomass content. Comparative Examples 3 and 4 contain a specified amount of high-density polyethylene (HDPE) as a biomass polyethylene other than the biomass polyethylene (b), but are very stiff and immediately separate into several parts when bent in a TD cracking test, i.e., they crack. Comparative Examples 5 to 8 use PP-3 as a propylene-based (co)polymer other than the propylene-based (co)polymer (a), but they contain a high content of volatile components and are inferior in cleanliness. Comparative Example 5 has a low biomass content, and Comparative Examples 6 and 8 are inferior to Examples 1 and 4, respectively, in the TD cracking test and crack easily. Comparative Example 9 uses only biomass polyethylene (b) LDPE, and although it has excellent crack resistance, it has extremely low rigidity and is unable to exhibit sufficient rigidity by itself.

The propylene-based polymer composition of the present invention produces molded articles that are excellent in rigidity and do not crack, even when containing biomass polyethylene. With a biomass content of 8.4 to 49%, it is useful for reducing environmental impact.

Claims (3)

A propylene-based polymer composition for injection molding contains 51 to 90 parts by weight of a propylene-based (co)polymer (a) satisfying the following conditions (Hi) to (Hv) and 10 to 49 parts by weight of a biomass polyethylene (b) satisfying the following condition (Li), with a total weight of 100 parts by weight, and has a biomass content of 8.4 to 49%.
(Hi) A metallocene-based propylene homopolymer or a metallocene-based propylene copolymer comprising propylene and an α-olefin content of less than 1% by weight.
(H-ii) The melt flow rate according to JIS K7210 (230°C, 2.16 kg load) is in the range of 0.5 to 100 g/10 min.
(H-iii) The melting peak temperature (Tm) is in the range of 135 to 165°C.
(H-iv) The molecular weight distribution (weight average molecular weight/number average molecular weight) is in the range of 1.5 to 4.0.
(Hv) The content of volatile components is 50 ppm by weight or less.
(Li) Low density polyethylene or linear low density polyethylene. A propylene polymer composition for injection molding, comprising 0.01 to 0.6 parts by weight of a nucleating agent per 100 parts by weight of the propylene polymer composition according to claim 1. A molded article obtained by using the propylene polymer composition for injection molding according to claim 1 or 2.