JP2003082178A - Polypropylene resin composition for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene resin composition for injection molding excellent in transparency and rigidity, and an injection molding form obtained by using the polypropylene resin composition. SOLUTION: This polypropylene resin composition for injection molding comprises 100 pts.wt. of a polypropylene resin (A), 0.001-5 pts.wt. of phosphites (B) represented by a specific formula and 0.01-2 pts.wt. of at least one kind of aromatic phosphate (C) represented by a specific formula, and the injection molding form is obtained by using the polypropylene resin composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene resin composition for injection molding and an injection molded article obtained by using the same. More specifically, the present invention relates to a polypropylene resin composition for injection molding, which has an excellent balance of transparency and rigidity, and an injection molded article obtained by using the same.

[0002]

BACKGROUND OF THE INVENTION Polypropylene resins are widely used for food containers, medical containers, containers, exterior parts for home appliances, automobile parts, etc. because they are excellent in rigidity, processing stability, moldability, etc. and are inexpensive. ing.

As an antioxidant for improving the processing stability of a resin, for example, JP-A-10-273494 describes phosphite esters having a specific structure. It is described that a polypropylene resin composition containing an ester and a nucleating agent may be added to the resin composition. However, in fields of application such as food containers, medical containers, and containers, improvement of the balance between transparency and rigidity, particularly improvement of transparency, has been desired.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polypropylene resin composition for injection molding, which has an excellent balance of transparency and rigidity, and an injection molded article obtained using the same.

[0005]

DISCLOSURE OF THE INVENTION In view of such circumstances, the present inventors have made earnest studies and, as a result, have found that a polyolefin-based resin having a constant blending amount and a specific phosphite ester having a blending amount within a specific range. And a polypropylene resin composition for injection molding containing at least one specific aromatic phosphoric acid ester having a compounding amount in a specific range and an injection-molded article obtained using the same have been found to be able to solve the above problems. The present invention has been completed.

That is, the present invention comprises 100 parts by weight of a polypropylene resin (A) and the following general formula (I): (In the formula, R ¹ , R ² , R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl having 6 to 12 carbon atoms. Group, an aralkyl group having 7 to 12 carbon atoms or a phenyl group, R ³ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, X represents a sulfur atom or a —CHR ⁶ — group (R ⁶ represents a hydrogen atom,
An alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms is shown. ), And n is 0 or 1. A is an alkylene group having 2 to 8 carbon atoms * -CO (R ⁷⁾ m-
Represents a group (R ⁷ represents an alkylene group having 1 to 8 carbon atoms, * represents a portion bonded to an oxygen atom, and m is 0 or 1). One of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ) 0.001 to 5 parts by weight of the phosphite ester (B) represented by the following general formula (II) (In the formula, R ⁸ represents a divalent hydrocarbon group having 1 to 10 carbon atoms, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and 1 represents 1 or 2.) A polypropylene-based resin composition for injection molding containing 0.01 to 2 parts by weight of at least one aromatic phosphoric acid ester (C) represented by 2) and an injection-molded article obtained by using the same. is there. Hereinafter, the present invention will be described in detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene resin (A) used in the present invention means a homopolymer of propylene, a copolymer of propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms, or a copolymer thereof. It is a mixture. Examples of the α-olefin having 4 to 20 carbon atoms include butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, decene-1 and the like. Is butene-1, hexene-1,
Octene-1, and these α-olefins may be used alone or in combination of two or more kinds.

Examples of the copolymer of propylene and ethylene and / or α-olefin having 4 to 20 carbon atoms include, for example, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1. Copolymers, propylene-hexene-1 copolymers, propylene-ethylene-hexene-1 copolymers and the like can be mentioned, preferably propylene-ethylene copolymers, propylene-
Butene-1 copolymer, propylene-ethylene-butene-
1 copolymer.

The polypropylene resin (A) is preferably a crystalline propylene homopolymer, a crystalline copolymer of propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms, or a mixture thereof. .

The term "crystalline" means that soluble in cold xylene (20 ° C. xylene) contained in a crystalline propylene homopolymer or a crystalline propylene / ethylene and / or a C4-20 α-olefin copolymer. It can be determined by the amount of parts (CXS). Cold xylene soluble part (CX
A large amount of S) indicates a large amount of amorphous (non-crystalline) portion and low crystallinity, and a small amount of cold xylene-soluble portion (CXS) indicates a small amount of amorphous (amorphous) portion and high crystallinity. Show. As a cold xylene soluble part (CXS),
From the viewpoint of rigidity, it is preferably 30% by weight or less, more preferably 20% by weight or less, particularly preferably 15% by weight or less.
It is less than or equal to weight%.

The crystalline copolymer of propylene and ethylene and / or α-olefin having 4 to 20 carbon atoms includes, for example, crystalline propylene-ethylene copolymer and crystalline propylene-butene-1 copolymer. , Crystalline propylene-ethylene-butene-1 copolymer, crystalline propylene-hexene-1 copolymer, crystalline propylene-ethylene-hexene-1 copolymer and the like, and preferably crystalline propylene-ethylene copolymer. A polymer, a crystalline propylene-butene-1 copolymer, and a crystalline propylene-ethylene-butene-1 copolymer.

Ethylene and / or C 4-20 α- in a crystalline copolymer of propylene and ethylene and / or C 4-20 α-olefin.
The content of olefin is not particularly limited, but is usually 0.
It is 5 to 15% by weight, and preferably 0.1 from the viewpoint of rigidity.
It is 5 to 5% by weight.

The intrinsic viscosity [η] of the polypropylene resin (A) used in the present invention is not particularly limited and is usually 0.5 to 4 dl / g, which is preferable from the viewpoint of moldability. It is 1 to 3 dl / g.

The polyolefin-based resin (A) according to the present invention may contain polyethylene, polybutene-1, styrene-based resin, ethylene / α-olefin as needed, as long as the object and effect of the present invention are not impaired. Polymer rubber,
A polyolefin-based polymer such as ethylene-propylene-diene copolymer rubber may be added.

The phosphite ester (B) used in the present invention is represented by the following general formula (I) (In the formula, R ¹ , R ² , R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl having 6 to 12 carbon atoms. Group, an aralkyl group having 7 to 12 carbon atoms or a phenyl group, R ³ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, X represents a sulfur atom or a —CHR ⁶ — group (R ⁶ represents a hydrogen atom,
An alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms is shown. ), And n is 0 or 1. A is an alkylene group having 2 to 8 carbon atoms * -CO (R ⁷⁾ m-
Represents a group (R ⁷ represents an alkylene group having 1 to 8 carbon atoms, * represents a portion bonded to an oxygen atom, and m is 0 or 1). One of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ) Are phosphorous acid esters.

In the phosphite ester (B) represented by the general formula (I), the substituents R ¹ , R ² , R ⁴ and R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Represents a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group.

Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, i-
Examples include propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, t-pentyl group, i-octyl group, t-octyl group, 2-ethylhexyl group, and the like, having 5 carbon atoms. Examples of the cycloalkyl group having 8 to 8 include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group, and examples of the alkylcycloalkyl group having 6 to 12 carbon atoms include a 1-methylcyclopentyl group and 1- Methylcyclohexyl group, 1-
Examples thereof include a methyl-4-i-propylcyclohexyl group, and examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, an α-methylbenzyl group, an α, α-dimethylbenzyl group and the like.

R ¹ , R ² and R ⁴ are preferably an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, and an alkylcycloalkyl group having 6 to 12 carbon atoms. Among them, R ¹ and R ⁴ are more preferably a t-alkyl group such as a t-butyl group, a t-pentyl group and a t-octyl group, a cyclohexyl group and a 1-methylcyclohexyl group.

More preferably, R ² is methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group,
an alkyl group having 1 to 5 carbon atoms such as t-pentyl group,
More preferred are methyl group, t-butyl group and t-pentyl group.

R ⁵ is preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms, and more preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, i-propyl group, n-butyl group,
i-butyl group, sec-butyl group, t-butyl group, t-
It is an alkyl group having 1 to 5 carbon atoms such as a pentyl group.

The substituent R ³ is a hydrogen atom or has 1 to 8 carbon atoms.
The alkyl group having 1 to 8 carbon atoms includes, for example, the same alkyl groups as described above. Preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,
More preferably, it is a hydrogen atom or a methyl group.

Further, the substituent X is two when n is 0.
Groups having a phenoxy group skeleton are directly bonded
When n is 1, a sulfur atom or -CHR⁶−
Group (R ⁶Is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or carbon
The cycloalkyl groups of the numbers 5 to 8 are shown. ) Is represented. -CH
R⁶-Group is a methylene group, an alkyl group having 1 to 8 carbon atoms, or
Is a methyl substituted with a cycloalkyl group having 5 to 8 carbon atoms.
Represents a len group, wherein the substituent R⁶1 to 8 carbon atoms
As an alkyl group of 5 to 8 carbon atoms
Are the same alkyl groups and cycloalkyl groups as described above.
Groups. As the substituent X, preferably n is 0 and
A group having two phenoxy group skeletons is directly bonded
Or n is 1 and a methylene group or a group
Chill group, ethyl group, n-propyl group, i-propyl group,
n-butyl group, i-butyl group, t-butyl group, etc. are substituted
It is a methylene group.

The substituent A is an alkylene group having 2 to 8 carbon atoms or a * -CO (R ⁷ ) m-group (wherein R ⁷ is an alkylene group having 1 to 8 carbon atoms, * is a portion which is bonded to an oxygen atom). And m is 0 or 1.).

Examples of the alkylene group having 2 to 8 carbon atoms include ethylene group, propylene group, butylene group,
Examples thereof include a pentamethylene group, a hexamethylene group, an octamethylene group, and a 2,2-dimethyl-1,3-propylene group, and a propylene group is preferable. Also * -COR
The * in the ⁷ -group indicates that the carbonyl group is the part that bonds to the oxygen atom of the phosphite group. Examples of the alkylene group having 1 to 8 carbon atoms in R ⁷ include methylene group, ethylene group, propylene group, butylene group, pentamethylene group, hexamethylene group, octamethylene group,
2,2-dimethyl-1,3-propylene group and the like can be mentioned. * -CO (R ⁷⁾ as preferably m- group, m is 0
In a * -CO- group or,, m is 1 as R ⁷ is ethylene _{* -CO (CH 2 CH 2)} - a group.

One of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms or an aralkyloxy group having 7 to 12 carbon atoms, and the other is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Represent

Here, examples of the alkyl group having 1 to 8 carbon atoms include the same alkyl groups as described above, and examples of the alkoxy group having 1 to 8 carbon atoms include, for example, an alkyl portion having 1 to 8 carbon atoms as described above. Examples of the aralkyloxy group having 7 to 12 carbon atoms include an alkoxy group which is the same alkyl as the alkyl of, and, for example, an aralkyloxy group having an aralkyl portion which is the same aralkyl as the aralkyl having 7 to 12 carbon atoms. .

The phosphite ester (B) used in the present invention is preferably the following compound 1. The structure of Compound 1 is shown in Formula (Formula 1). Compound 1: 2,4,8,10-tetra-t-butyl-6
-[3- (3-Methyl-4-hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,
3,2] Dioxaphosphine

[Chemical 1]

The blending amount of the phosphite ester (B) used in the present invention is 100% polypropylene resin (A).
The amount is 0.001 to 5 parts by weight, preferably 0.01 to 1 part by weight, based on parts by weight. If the blending amount is less than 0.001 part by weight, the effect as an antioxidant may be insufficient, and if it exceeds 5 parts by weight, the antioxidant effect on the polypropylene resin will be saturated, which is uneconomical. It just becomes.

The aromatic phosphates (C) used in the present invention are represented by the following general formula (II) (In the formula, R ⁸ represents a divalent hydrocarbon group having 1 to 10 carbon atoms, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and 1 represents 1 or 2)). These aromatic phosphate esters may be used alone or in combination of two or more.

In the aromatic phosphoric acid ester (C) represented by the general formula (II), the substituent R ⁸ represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and a divalent group having 1 to 10 carbon atoms. Examples of the hydrocarbon group include an alkylene group and an alkylidene group. As the alkylene group, for example, a methylene group,
Examples thereof include an ethylene group and a propylene group, and a methylene group is preferable. Examples of the alkylidene group include an ethylidene group, an n-propylidene group and an i-propylidene group, and an ethylidene group is preferable.

R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, which has 1 to 10 carbon atoms.
Examples of the hydrocarbon group of 10 include an alkyl group and a phenyl group. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and an n-
A butyl group, an i-butyl group, a sec-butyl group, a t-butyl group and the like can be mentioned, and preferably both R ⁹ and R ¹⁰ are t.
A butyl group. l is 1 or 2.

Examples of the aromatic phosphoric acid ester (C) represented by the general formula (II) include hydroxyaluminum-bis [2,2'-methylene-bis (4,6-dimethylphenyl) phosphate] and hydroxy. Aluminum-bis [2,2'-ethylidene-bis (4,6-dimethylphenyl) phosphate], hydroxyaluminum-bis [2,2'-methylene-bis (4,6-diethylphenyl) phosphate], hydroxy Aluminum-bis [2,2'-ethylidene-bis (4,6-diethylphenyl) phosphate], hydroxyaluminum-bis [2,2'-methylene-bis (4,6-di-t-butylphenyl) phosphite Fate], and hydroxyaluminum-bis [2,2′-ethylidene-bis (4,6-di-t-butyl) Butylphenyl) phosphate], hydroxy aluminum - bis [2,2'-methylene - bis (4-methyl -6-t-butylphenyl) phosphate], hydroxy aluminum - bis [2,
2'-ethylidene-bis (4-methyl-6-t-butylphenyl) phosphate], hydroxyaluminum-bis [2,2'-methylene-bis (4-ethyl-6-)
t-Butylphenyl) phosphate], hydroxyaluminium-bis [2,2′-ethylidene-bis (4-
Ethyl-6-t-butylphenyl) phosphate],
Hydroxyaluminum-bis [2,2'-methylene-
Bis (4-i-propyl-6-t-butylphenyl) phosphate], hydroxyaluminum-bis [2,2]
2'-ethylidene-bis (4-i-propyl-6-t-
Butylphenyl) phosphate] and the like, preferably hydroxyaluminum-bis [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate], and hydroxyaluminum-bis [2. , 2'-ethylidene-bis (4,6-di-t-butylphenyl) phosphate]. Further, these aromatic phosphoric acid esters may be used alone or in combination of two or more kinds.

As the aromatic phosphoric acid ester (C) used in the present invention, a commercially available product may be used, for example, hydroxyaluminum-bis [2,2'-methylene-bis (4,6-di-t). -Butylphenyl) phosphate]
And an aliphatic monocarboxylic acid lithium salt mixture having 8 to 20 carbon atoms (Asahi Denka Co., Ltd., trade name ADEKA STAB NA21)
Etc.

The amount of the aromatic phosphoric acid ester (C) used in the present invention is 100% of the polypropylene resin (A).
It is 0.01-2 parts by weight, preferably 0.05-1 part by weight, more preferably 0.05-0.
5 parts by weight. If the amount of the aromatic phosphate ester (C) is less than 0.01 part by weight, the transparency improving effect may be insufficient, and if it exceeds 2 parts by weight, the transparency improving effect on the polypropylene resin may be improved. Is saturated and becomes uneconomical.

The polypropylene resin composition for injection molding of the present invention contains the polypropylene resin composition as long as the object and effect of the present invention are not impaired.
Other additives such as a neutralizing agent, a weatherproofing agent, a flame retardant, an antistatic agent, a plasticizer, a lubricant, and a copper damage inhibitor may be added.

The method for producing the polypropylene resin composition for injection molding of the present invention is not particularly limited and may be a known method. For example, polypropylene resin (A), phosphite ester (B) ) And aromatic phosphoric acid ester (C), and further, the above-mentioned various additives to be added as needed, are mixed using a mixer such as a tumbler mixer, a Henschel mixer, a ribbon blender, and then a uniaxial extruder, Examples thereof include a method of melt-kneading with a twin-screw extruder, Banbury mixer or the like to make the mixture uniform.

The injection-molded article obtained by using the polypropylene resin composition for injection molding of the present invention can be used in fields of application where transparency and rigidity are required. Particularly preferred applications are food containers and medical containers. , A container.

[0038]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Physical properties of each item of Examples and Comparative Examples,
It measured according to the following method. (1) Intrinsic viscosity ([η]) (unit: dl / g) Using an Ubbelohde type viscosity system, the reduced viscosities were measured at three concentrations of 0.1, 0.2 and 0.5 dl / g. The intrinsic viscosity is described in “Polymer Solution, Polymer Experimental Studies 11” (198).
2 years Kyoritsu Shuppan Co., Ltd.) The calculation method described on page 491, that is, the reduced viscosity was plotted with respect to the concentration, and the concentration was extrapolated to zero. The measurement was performed at a temperature of 135 ° C. using tetralin as a solvent.

(2) Cold xylene-soluble part (CXS) (unit: wt%) 5 g of a sample was completely dissolved in 500 ml of boiling xylene, cooled to 20 ° C. and left for 4 hours. Then, this was separated into a precipitate and a solution by filtration, the solvent was removed from the filtrate, and the residue was dried under reduced pressure at 70 ° C. The weight of the dried residue was measured and the content was calculated.

(3) Ethylene content (unit: weight%) Polymer Analysis Handbook (1985, published by Asakura Shoten)
In accordance with the method described in the paragraph of "(i) Random copolymer" on page 256 of the above, it was measured using IR spectrum.

(4) Transparency (haze, unit:%) Measured according to JIS K7150. The test piece had a diameter of 300 mm and a thickness of 1 obtained by injection molding described later.
A disc-shaped injection-molded body of mm was cut into a 3 cm × 3 cm square at about 6 cm from the center point. The higher the haze value, the whiter the test piece looks like haze and the lower the transparency is.

(5) Flexural modulus (FM, unit: MPa) It was measured according to JIS K7203. A test piece obtained by injection molding described below was used, and the flexural modulus was measured under the following conditions. Measurement conditions Test piece thickness: 6.4 mm Span length: 100 mm Load speed: 2.5 mm / min Measurement temperature: 23 ° C. Bending elastic modulus is an index of rigidity. The larger the bending elastic modulus value, the better the rigidity. Indicates.

Reference Example 1 (1-1) Production of solid catalyst component (A) (a) Synthesis of organomagnesium compound 10 equipped with stirrer, reflux condenser, dropping funnel, thermometer
After replacing the 00 ml flask with argon, 32.0 g of ground magnesium for Grignard was added. Add 120 g of butyl chloride and 5 parts of dibutyl ether to the dropping funnel.
Charge 00 ml and add about 30 to the magnesium in the flask.
ml was added dropwise to start the reaction. After the reaction was started, the dropping was continued at 50 ° C. for 4 hours, and after the dropping was completed, the reaction was further conducted at 60 ° C. for 1 hour.
The reaction continued for an hour. Then, the reaction solution was cooled to room temperature,
The solid content was filtered off to obtain an organomagnesium compound solution.
The obtained organomagnesium compound solution was sampled, butylmagnesium chloride in the solution was hydrolyzed with 1N sulfuric acid, and the concentration was determined by backtitration with 1N sodium hydroxide aqueous solution (phenolphthalein was used as an indicator. Used), and the concentration was 2.1 mol / liter.

(B) Synthesis of solid product After replacing a 500 ml flask equipped with a stirrer and a dropping funnel with argon, 290 ml of hexane, 9.3 ml (9.3 g, 27 mmol) of tetrabutoxytitanium, and diisobutyl phthalate. 8.5 ml (8.8 g, 32 mmol) and 79.1 ml tetraethoxysilane (74.
4 g, 357 mmol) was added to make a uniform solution. Next, 189 ml of the organomagnesium compound solution synthesized in (a) above was added while keeping the temperature in the flask at 5 ° C.
It dripped gradually from the dropping funnel over 2 hours. After completion of dropping, the mixture was stirred at room temperature for 1 hour and then solid-liquid separated at room temperature.
Washing was repeated 3 times with 300 ml of hexane and 3 times with 300 ml of toluene, and then 270 ml of toluene was added to obtain a solid product slurry. A part of the solid product slurry was sampled and the composition was analyzed. As a result, the solid product contained 1.8% by weight of titanium atoms and 0.5% of phthalate ester.
% By weight, 30.7% by weight of ethoxy groups and 3.3% by weight of butoxy groups. The slurry concentration is
It was 0.140 g / ml.

(C) Synthesis of ester-treated solid After replacing a 200 ml flask equipped with a stirrer, dropping funnel, and thermometer with argon, 84 ml of the solid product slurry obtained in (b) above was charged, and further, 12.1 ml of the supernatant liquid was withdrawn and diisobutyl phthalate 7.8
ml (29 mmol) was added and the reaction was carried out at 95 ° C. for 30 minutes. After the reaction, solid-liquid separation was performed, and the obtained solid was toluene 5
It was washed twice with 9 ml.

(D) Synthesis of solid catalyst component (activation treatment) After the washing of the solid obtained in (c) above was completed, 15.3 ml of toluene and 0.66 m of diisobutyl phthalate were placed in the flask.
l (2.5 mmol), butyl ether 1.2 ml
(6.9 mmol), and titanium tetrachloride 23.4 ml
(0.213 mol) was added and the reaction was carried out at 95 ° C for 3 hours. After completion of the reaction, solid-liquid separation was carried out at the same temperature, and then washing with 59 ml of toluene was carried out twice at the same temperature. Then, 12.0 ml of toluene, 1.2 ml (6.9 mmol) of butyl ether, and 11.7 ml (0.106 ml) of titanium tetrachloride.
Mol) was added and the reaction was carried out at 95 ° C for 1 hour. After completion of the reaction, solid-liquid separation was performed at the same temperature, and then 59 m of toluene was added at the same temperature.
After being washed 3 times with 1 l, washed with 59 ml of hexane 3 times and further dried under reduced pressure to obtain 8.1 g of the solid catalyst component (A).
Got In the solid catalyst component (A), titanium atoms are 1.
It contained 4% by weight, 20.3% by weight of magnesium atom, 10.0% by weight of phthalic acid ester, and 62.6% by weight of halogen atom. Further, when the solid catalyst component (A) was observed with a stereoscopic microscope, it had good particle properties without fine powder.

(1-2) Polymerization of Crystalline Propylene-Ethylene Copolymer (PP1) (a) Preliminary Polymerization After sufficiently purified hexane was added to a reactor equipped with a stirrer, the system was sufficiently replaced with nitrogen. , Triethylaluminum (hereinafter abbreviated as TEA), cyclohexylethyldimethoxysilane (hereinafter abbreviated as CHEDMS) and the solid catalyst component (A) obtained in Reference Example 1 were added, and propylene was continuously added for 2 hours while maintaining 25 ° C. Was added to obtain a prepolymer slurry.

(B) Using a gas phase fluidized bed polymerization tank equipped with a main polymerization stirrer, a polymerization temperature of 80
° C., polymerization pressure 18kg / cm ² G, in the vapor phase ethylene concentration 2.5 vol. %, The hydrogen concentration is 2.7 vol. %, So that the prepolymer slurry, TEA, C
HEDMS (CHEDMS / TEA = 0.31 (mol /
Mol)) was supplied to perform continuous gas phase polymerization to obtain a crystalline propylene-ethylene copolymer (PP1) as a resin powder. The obtained crystalline propylene-ethylene copolymer (PP1) had an ethylene content of 4.4% by weight and CXS.
Was 3.5 wt% and the intrinsic viscosity [η] was 1.6 dl / g.

Reference Example 2 (2-1) Polymerization of crystalline propylene homopolymer (PP2) In (1-2) (b) main polymerization of Reference Example 1, the ethylene concentration in the gas phase was changed to zero, Hydrogen concentration is 3.87vo
l. A crystalline propylene homopolymer (PP2), which is a resin powder, was obtained in the same manner as in Reference Example 1 except that the content was changed to%.
The obtained crystalline propylene homopolymer (PP2) was C
XS 0.5% by weight, intrinsic viscosity [η] 1.3 dl / g
Met

Example 1 (1-1) Polypropylene Resin Composition for Injection Molding 80 parts by weight of the crystalline propylene-ethylene copolymer (PP1) obtained in Reference Example 1 and Reference Example 2 were obtained. 2,4,8,10-Tetra-t-butyl-6- [3 with respect to polypropylene-based resin powder (total 100 parts by weight) consisting of 20 parts by weight of crystalline propylene homopolymer (PP2).
-(3-Methyl-4-hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,3,2]
0.3 parts by weight of dioxaphosphepine (trade name: Sumilizer GP, manufactured by Sumitomo Chemical Co., Ltd.), and hydroxyaluminum-bis [2,2'-methylene-bis (4
6-di-t-butylphenyl) phosphate] and a lithium salt of an aliphatic monocarboxylic acid having 8 to 20 carbon atoms (Adeka Stab NA21, manufactured by Asahi Denka Co., Ltd.).
1 part by weight and 0.05 part by weight of calcium stearate as a neutralizing agent were further mixed and mixed with a Henschel mixer. The obtained mixture was melted and kneaded into pellets using a single screw extruder having a diameter of 40 mm (manufactured by Tanabe Seisakusho Co., Ltd.) at a set temperature of 220 ° C. and a screw rotation speed of 100 rpm.
The blending amount of each component of the obtained polypropylene resin composition is shown in Table 1.

(1-2) Injection-Molded Article Using the following apparatus, the pellets obtained by the melt-kneading were injection-molded to obtain an injection-molded article. Equipment: Sumitomo Heavy Industries Nestal Cycap 120t Molding temperature: 220 ℃ Mold setting temperature: 50 ℃

(1-3) Measurement of Physical Properties Using the obtained injection-molded article, the transparency (haze) and the flexural modulus were measured according to the methods described above. The obtained measurement results are shown in Table 2.

Example 2 Pellets were obtained in the same manner as in Example 1 except that the amount of the ADEKA STAB NA21 used in Example 1 was changed to 0.3 parts by weight, and the obtained pellets were injection-molded to obtain a pellet. The transparency (haze) and flexural modulus were measured using the injection-molded product. Table 1 shows the blending amount of each component of the obtained polypropylene resin composition, and Table 2 shows the obtained measurement results.

Comparative Example 1 The ADEKA STAB NA21 used in Example 1 was changed to pt-butyl aluminum benzoate, and the compounding amount was 0.1.
Pellets were obtained by the same method as in Example 1 except for changing to parts by weight, the obtained pellets were injection-molded, and the resulting injection-molded body was used to obtain transparency (haze) and flexural modulus. It was measured. Table 1 shows the blending amount of each component of the obtained polypropylene resin composition, and Table 2 shows the obtained measurement results.

Comparative Example 2 By the same method as in Example 1, except that the ADEKA STAB NA21 used in Example 1 was changed to pt-butyl aluminum benzoate and the compounding amount was changed to 0.3 part by weight. Pellets were obtained, the obtained pellets were injection-molded, and the resulting injection-molded body was used to measure transparency (haze) and flexural modulus. Table 1 shows the blending amount of each component of the obtained polypropylene resin composition, and Table 2 shows the obtained measurement results.

[0056]

[Table 1]

[0057]

[Table 2]

Examples 1 and 2 satisfying the requirements of the present invention
Is a polypropylene resin composition for injection molding, which has an excellent balance of transparency and rigidity, and an injection molded article obtained by using the same. On the other hand, Comparative Examples 1 and 2 which did not use the aromatic phosphoric acid ester (C), which is a requirement of the present invention, have low transparency.

[0059]

As described above in detail, according to the present invention, it is possible to obtain a polypropylene resin composition for injection molding which has an excellent balance of physical properties of transparency and rigidity and an injection molded article obtained by using the same.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Okawa             Sumitomo Chemical Co., Ltd. 1-5 Anezaki Kaigan, Ichihara City, Chiba Prefecture             Business F term (reference) 4F071 AA15X AA20 AA20X AA21X                       AC15 AE05 AH05 BA01 BB05                 4F206 AA11 JA07 JQ81                 4J002 BB121 BB141 BB151 EW047                       EW066 FD036 FD037 GG01

Claims (2)

[Claims] 1. A polypropylene resin (A) (100 parts by weight) and the following general formula (I): (In the formula, R ¹ , R ² , R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl having 6 to 12 carbon atoms. Group, an aralkyl group having 7 to 12 carbon atoms or a phenyl group, R ³ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, X represents a sulfur atom or a —CHR ⁶ — group (R ⁶ represents a hydrogen atom,
An alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms is shown. ), And n is 0 or 1. A is an alkylene group having 2 to 8 carbon atoms * -CO (R ⁷⁾ m-
Represents a group (R ⁷ represents an alkylene group having 1 to 8 carbon atoms, * represents a portion bonded to an oxygen atom, and m is 0 or 1). One of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ) 0.001 to 5 parts by weight of the phosphite ester (B) represented by the following general formula (II) (In the formula, R ⁸ represents a divalent hydrocarbon group having 1 to 10 carbon atoms, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and 1 represents 1 or 2. A polypropylene resin composition for injection molding, comprising 0.01 to 2 parts by weight of at least one aromatic phosphoric acid ester (C) represented by 2.). 2. An injection-molded article obtained by using the polypropylene resin composition for injection molding according to claim 1.