JPH10158330A - Polypropylene resin for injection molding container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene resin for injection molding containers, capable of readily providing containers having good transparency and thin wall thickness by constituting the polypropylene resin so as to have a prescribed melt flow, a prescribed isotactic index, a prescribed difference in molding shrinkage factor and a prescribed heat distortion temperature. SOLUTION: This polypropylene resin comprises a polypropylene polymer A. In the polymer A, (i) melt flow rate is 10-60g/10min and (ii) isotactic index is 85-99.5 and (iii) when molding shrinkage factor in injecting direction (vertical direction) of polypropylene resin in molding product is defined as L1 and molding shrinkage factor in the direction (lateral direction) perpendicular to the injecting direction is defined as L2, the absolute value of the difference LR in molding shrinkage factor calculated by the formula is -10% and heat distortion temperature of the polypropylene resin molding product is >=115 deg.C. Furthermore, the polymer A is preferably produced by using a catalyst for metallocene- based olefin polymerization and the polypropylene resin preferably contains a nucleating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin for an injection-molded container, and more particularly, to a polypropylene resin for an injection-molded container suitably used for producing a thin and thick food injection-molded container having good transparency.

[0002]

2. Description of the Related Art Conventionally, cup-shaped containers having a wall thickness of 2 mm or less have been used for dessert packaging of pudding, jelly and the like, which have been thin-walled injection-molded containers having good transparency. Containers for this purpose are required not to deform when the contents are heat-treated. In addition, when the molding shrinkage in the direction in which the resin is injected from the nozzle, that is, the injection direction (vertical direction), and the molding shrinkage in the direction orthogonal to the injection direction (horizontal direction) are significantly different from each other at the time of molding the container, the injection may occur. Since deformation occurs during molding, a good balance between the molding shrinkage in the vertical direction and the molding shrinkage in the horizontal direction is required.

[0003] However, the polypropylene resin conventionally used for cup-shaped containers does not always have a good balance between the molding shrinkage in the vertical direction and the molding shrinkage in the horizontal direction during molding of the container. Deformation sometimes occurred. Further, since the conventionally used polypropylene resin does not always have sufficient heat resistance, the container may be deformed during the heat treatment of the content.

[0004] Accordingly, a thin-walled injection-molded container having good transparency, particularly a cup-shaped container, has an excellent balance between the molding shrinkage in the vertical direction and the molding shrinkage in the horizontal direction when molded.
In addition, the appearance of a polypropylene resin for an injection molded container having good heat resistance has been desired.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to further improve the prior art as described above, and it is intended to reduce the molding shrinkage in the vertical direction when molding a thin-walled injection-molded container having good transparency, particularly a cup-shaped container. It is an object of the present invention to provide a polypropylene resin for an injection-molded container which has an excellent balance between the modulus and the molding shrinkage in the lateral direction and has a high heat distortion temperature.

[0006]

The polypropylene resin for an injection molded container according to the present invention is a polypropylene resin comprising a propylene polymer (A), wherein the propylene polymer (A) comprises (i)
Melt flow rate (ASTM D 1238, 230 ℃, load 2.16k
g) is in the range of 10 to 60 g / 10 minutes, (ii) the isotactic index (II) is in the range of 85 to 99.5, and (iii) the injection direction of the polypropylene resin in the polypropylene resin molded article ( L1)
When the molding shrinkage in the direction (lateral direction) perpendicular to the injection direction is L2, the molding shrinkage difference (LR) calculated by the formula LR [%] = [(L1−L2) × 100] / L1 ) Is 10% or less, and (iv) the heat distortion temperature of the polypropylene resin molded product is 115 ° C. or more.

[0007] The propylene polymer (A) is preferably produced using a metallocene olefin polymerization catalyst.
In addition to the propylene polymer (A), a crystal nucleating agent (B)
May be contained.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the polypropylene resin for an injection molded container according to the present invention will be specifically described.

The polypropylene resin for an injection-molded container according to the present invention comprises a propylene polymer (A) and, if necessary, additives such as a nucleating agent (B). Propylene polymer (A) The propylene polymer (A) used in the present invention is preferably a propylene homopolymer, but α-
The olefin may be copolymerized at a ratio of 3 mol% or less. The propylene polymer (A) is produced by various production methods, and particularly, polypropylene prepared using a metallocene-based olefin polymerization catalyst is preferable.

The propylene polymer (A) has a melt flow rate (ASTM D 1238, 230 ° C., load 2.16 kg) of 10
６０60 g / 10 min, preferably 20-60 g / 10 min. The polypropylene resin comprising the propylene polymer (A) having the above melt flow rate has excellent fluidity.

The propylene polymer (A) has an isotactic index (II) in the range of 85 to 99.5, preferably 90 to 99. When a polypropylene resin comprising the propylene polymer (A) having the above isotactic index is used, a container having excellent rigidity, heat resistance and transparency can be formed.

The above isotactic index (II)
Is a numerical value obtained by extracting 5 g of frozen and pulverized powder with n-heptane for 2 hours using a Soxhlet extractor, and converting the remaining amount of extraction to a value when the charged powder amount is 100.

In the polypropylene resin molded article injection-molded from the propylene polymer (A) used in the present invention, the molding shrinkage ratio in the injection direction (longitudinal direction) of the polypropylene resin is represented by L1, and the direction perpendicular to the injection direction (lateral direction). )
Assuming that the molding shrinkage is L2, the absolute value of the molding shrinkage difference (LR) calculated by the formula LR [%] = [(L1-L2) * 100] / L1 is 10% or less, preferably 5% or less. % Or less.

The heat distortion temperature of a polypropylene resin molded article injection-molded from the propylene polymer (A) is 1
15 ° C. or higher. In the present invention, the test piece obtained under the actual molding conditions may show the absolute value of the difference in the molding shrinkage and the heat deformation temperature. However, a propylene polymer (A) that satisfies the above conditions at a molding temperature as low as possible, for example, 200 ° C., is preferred.

The propylene polymer (A) as described above is
As described above, a metallocene-based olefin polymerization catalyst,
That is, a polymer prepared using a catalyst containing a metallocene compound is preferable. Examples of such a metallocene-based olefin polymerization catalyst include (a) a metallocene compound having a cyclopentadienyl skeleton, (b) (b-1) an organoaluminum compound, (b-2) an organoaluminum oxy compound, (b-3) at least one selected from a Lewis acid or an ionic compound containing a boron atom
Catalysts consisting of different cocatalyst components can be used.

(A) Metallocene Compound As the metallocene compound (a), for example, two ligands having a cyclopentadienyl skeleton represented by the following formula (I) are bonded via a divalent bonding group The used metallocene compound is used.

[0017]

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In the formula, M is a transition metal atom belonging to Groups IV to VIB of the periodic table, and specifically, zirconium, titanium, hafnium and the like. R ¹ , R ² , R ³ and R ⁴
Are each independently a hydrogen atom, a halogen atom such as chlorine,
1 to 20 carbon atoms which may have a halogen substituent
Hydrocarbon group, silicon-containing group, oxygen-containing group, sulfur-containing group, nitrogen-containing group or phosphorus-containing group. Note each other for example, two R ¹ as indicated by the same suffix may be be the same or different. R ¹ , R ² , R ^3, and R ⁴ may form a ring together with the carbon atom to which these groups are bonded by part of the groups adjacent to each other, or form a ring by bonding to each other Preferred combinations of the cases are indicated by the same suffix.

Examples of the hydrocarbon group having 1 to 20 carbon atoms include an alkyl group, a cycloalkyl group, an alkenyl group, an arylalkyl group, an aryl group and an araryl group, for example, groups such as methyl, ethyl, propyl and butyl. Is mentioned.

The ring formed by the bonding of the hydrocarbon groups includes a fused ring such as a benzene ring, a naphthalene ring, an acenaphthene ring and an indene ring, and the hydrogen atom of the fused ring is methyl, ethyl, n-propyl, Examples include groups substituted with an alkyl group such as iso-propyl, n-butyl, iso-butyl, and tert-butyl.

X ¹ and X ² may be the same or different, and each represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may be substituted by halogen,
It is an oxygen-containing group, a sulfur-containing group or a silicon-containing group.

Y is a divalent hydrocarbon group having 1 to 20 carbon atoms which may be substituted by halogen, a divalent silicon-containing group, a divalent germanium-containing group, a divalent tin-containing group,
-O -, - CO -, - S -, - SO -, - SO 2 -, -
NR ^5- , -P (R ⁵ )-, -P (O) (R ⁵ )-, -B
R ⁵ — or —AlR ⁵ — (wherein R ⁵ may be the same or different from each other, and may be a hydrogen atom, a halogen atom or a halogenated carbon atom having 1 to 20 carbon atoms as exemplified above. Is a hydrocarbon group.).

Hereinafter, specific examples of the metallocene compound represented by the formula (I) will be shown. rac-dimethylsilylenebis (2,3,
5-trimethylcyclopentadienyl) zirconium dichloride, rac-dimethylsilylenebis (2,4,7-trimethylcyclopentadienyl) zirconium dichloride, rac-
Dimethylsilylenebis (2-methyl-4-tert-butylcyclopentadienyl) zirconium dichloride and the like.

Further, there may be mentioned compounds in which zirconium in the compounds exemplified above is replaced with titanium or hafnium. In the present invention, among the metallocene compounds represented by the formula (I), a metallocene compound represented by the following general formula (II) or (III) is preferable.

[0025]

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In the formula, M, Y, X ¹ and X ² are the same as in the above formula (I). R ^{11 s} may be the same or different and are each a hydrocarbon group having 1 to 6 carbon atoms, and specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl Tert-butyl, n-pentyl, neopentyl, n-hexyl, cyclohexyl and the like; alkyl groups such as vinyl and propenyl; and the like. Of these, a primary alkyl group in which the carbon atom bonded to the indenyl group is preferred,
Further, an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group and an ethyl group are particularly preferable.

R ¹² , R ¹⁴ , R ¹⁵ and R ¹⁶ may be the same or different and are each a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 6 carbon atoms similar to R ¹¹ . R ¹³ may be the same or different from each other, and may be a hydrogen atom or an aryl group having 6 to 16 carbon atoms, specifically, phenyl, α-naphthyl, β-naphthyl, anthryl, phenanthryl, pyrenyl, acenaphthyl, phenalenyl, Aceanthrenyl, tetrahydronaphthyl,
Indanyl, biphenylyl and the like. Of these, phenyl, naphthyl, anthryl, and phenanthryl are preferred.

R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ may form a ring together with a carbon atom to which a part of the groups adjacent to each other is bonded. These aryl groups may be substituted with a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms similar to the above R ^{1 to} R ⁴ , or an organic silyl group.

As the metallocene compound represented by the above formula (II), specifically, rac-dimethylsilylenebis {1-
(2-methyl-4-phenylindenyl) zirconium dichloride, rac-dimethylsilylenebis 1- (2-methyl-4
-(Α-naphthyl) indenyl)｝ zirconium dichloride, rac-dimethylsilylenebis ｛1- (2-methyl-4,5-benzoindenyl)｝ zirconium dichloride and the like.

The metallocene compound represented by the above formula (II) can be obtained from Journal of Organome-tallic Chem. 288 (19)
85), pp. 63-67, European Patent Application 0,320,76.
It can be manufactured according to the description of No. 2 and Examples.

[0031]

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In the formula, M, Y, X ¹ and X ² are the same as in the above formula (I). R ²¹ and R ²² may be the same or different from each other, and among R ¹ or R ³ , R ²¹ is a hydrocarbon group having 1 to 20 carbon atoms, particularly methyl, ethyl or propyl. It is preferably 1 to 3 hydrocarbon groups. R ²² is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, particularly a hydrogen atom or methyl,
It is preferably a hydrocarbon group having 1 to 3 carbon atoms of ethyl and propyl.

R ²³ and R ²⁴ may be the same or different from each other, and are an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group as exemplified as R ^{1 to} R ⁴ . Among them, R ²³ is preferably a secondary or tertiary alkyl group.

Specific examples of the metallocene compound represented by the above general formula (III) include rac-dimethylsilylenebis {1- (2,7-dimethyl-4-i-propylindenyl)} zirconium dichloride and rac -Dimethylsilylene bis ｛1-
(2,7-dimethyl-4-t-butylindenyl)} zirconium dichloride.

Of these, i-propyl, se in the 4-position
Those having a branched alkyl group such as c-butyl and tert-butyl are particularly preferred. The metallocene compound represented by the above formula (III) can be synthesized from an indene derivative by a known method, for example, a method described in JP-A-4-268307.

In the present invention, the metallocene compound (a)
A C ₁ symmetric metallocene compound represented by the following formula (IV) can also be used.

[0037]

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Wherein M ¹ is Sc, Y, Ti, Zr, Hf or a lanthanide transition metal atom. R ³¹ , R ³² , R
³³ is independently a hydrocarbon group having 1 to 20 carbon atoms or an alkylsilyl group. ^{R 34, R 35, R 36} , R
³⁷ is each independently a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms or an alkylsilyl group. These R ³¹
Group adjacent to each other in to R ³⁷ may form a ring through a hydrocarbon group.

X ¹ and X ² are the same as in the above formula (I).
Y ¹ is an alkylene group, a silylene group, or a germylene group; R ³⁸ and R ³⁹ are each independently a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or an alkylsilyl group; A ring may be formed via a group.
n is 1, 2 or 3.

Specific examples of the above-mentioned hydrocarbon group and alkylsilyl group include the same groups as in the above formula (I).
As the C ₁ symmetric metallocene compound represented by the formula (IV), for example, when M ¹ is zirconium,
Isopropylidene (cyclopentadienyl) (methylcyclopentadienyl) zirconium dichloride, dimethylsilylene (tetramethylcyclopentadienyl) (3-
t-butylcyclopentadienyl zirconium) dichloride, isopropylidene (3-t-butylcyclopentadienyl) (fluorenyl) zirconium dichloride, and the like.

In the present invention, the metallocene compound (a) as described above is (b-1) an organoaluminum compound, (b-2) an organoaluminum oxy compound and (b-3) a Lewis acid containing a boron atom or Used together with at least one cocatalyst component (b) selected from ionic compounds.

(B-1) Organoaluminum Compound (b-1) The organoaluminum compound used in the present invention is:
For example, it is represented by the following equation (V).

[0043] In ^{_{R a n AlX 3-n ...}} (V) ( wherein, R ^a is a hydrocarbon group having 1 to 12 carbon atoms, specifically methyl, ethyl, n- propyl, isopropyl, isobutyl, An alkyl group such as pentyl, hexyl, octyl, cyclopentyl, cyclohexyl, phenyl and tolyl, a cycloalkyl group or an aryl group, X is a halogen atom or a hydrogen atom, and n is 1 to
3. (B-2) Organoaluminum oxy compound (b-2) The organoaluminum oxy compound may be a conventionally known aluminoxane.
It may be a benzene-insoluble organic aluminum oxy compound as exemplified in JP-A-7.

(B-3) A Lewis acid containing a boron atom or
Is a ionic compound (b-3) The Lewis acid or ionic compound containing a boron atom used in the present invention is represented, for example, by the following formula (VII).

BR ₃ ... (VII) In the formula (VII), R represents fluorine or fluorine, a methyl group,
It is a phenyl group which may have a substituent such as a trifluoromethyl group.

Examples of the ionic compound containing a boron atom include trialkyl-substituted ammonium salts, N, N-dialkylanilinium salts, dialkylammonium salts, and triarylphosphonium salts.

Examples of the ionic compound containing a boron atom include triphenylcarbenium tetrakis (pentafluorophenyl) boronate, N, N-dimethylaniliniumtetrakis (pentafluorophenyl) borate, and ferrocenium tetra (pentafluorophenyl) borate. Can also be mentioned.

Further, examples of the ionic compound containing a boron atom include salts of anions, borane, carborane complex compounds, salts of carborane anions, salts of metal carboranes, and metal borane anions.

In the present invention, the cocatalyst component (b) is
at least one selected from (b-1), (b-2) and (b-3)
A species may be used, and any one of (b-1), (b-2) and (b-3) may be used alone, or two or more of them may be used, or the respective components may be used in appropriate combination. .

Preparation of Propylene Polymer (A) In the present invention, when preparing the propylene polymer (A), the above-mentioned metallocene compound (a) and cocatalyst component (b) may be used as a catalyst. A solid catalyst in which some or all of these are supported on a carrier may be used.

In preparing the solid catalyst, the carrier has a particle size of 10 to 300 μm, preferably 20 to 200 μm.
m or granular or fine inorganic or organic compound is used. The support is preferably porous, and specifically has a specific surface area of 50 to 1000 m ² / g, preferably 100 to 700 m ³ / g, and a pore volume of 0.3 to 2.
It is preferably 5 cm ³ / g.

The solid catalyst can be prepared by mixing and contacting the metallocene compound (a), the cocatalyst component (b) and the carrier in an inert hydrocarbon solvent in any order.

In this solid catalyst, the metallocene compound (a) contained 5 × 10 ^-6 as a transition metal atom per 1 g of the carrier.
~ 5 × 10 ^-4 gram atoms, preferably 10 ^-5 to 2 × 10
^Preferably, it is carried in an amount of ^-4 gram atoms.

The cocatalyst component (b) contains 10 ^{-3 to} 5 × 10 ^-2 gram atoms as aluminum atoms per gram of the carrier,
Preferably in an amount of 2 × 10 ⁻³ to 2 × 10 ⁻² gram atoms,
5 × 10 ^{−8 to} 5 × 10 ⁻² gram atoms as boron atoms,
Preferably, the carrier is supported in an amount of 5 × 10 ^{−7 to} 5 × 10 ⁻³ gram atoms.

In the present invention, when propylene is polymerized using the above-mentioned catalyst, the catalyst may be used after preliminarily polymerizing olefins. In the present invention, when the propylene polymer (A) is prepared using the above-mentioned catalyst, the metallocene compound (a) is converted into a metallocene compound (a) having a concentration of 1 as a transition metal atom in the polymerization system.
0 ^-8 to 10 ^-3 gram atoms / liter, preferably 10 ^-7
Desirably, it is used in an amount of from 10 to 10 ^-4 gram atoms / liter.

When the organoaluminum compound (b-1) and / or the organoaluminumoxy compound (b-2) are used as the cocatalyst component (b), the aluminum in these compounds and the transition metal in the metallocene compound (a) are used. It is desirable to use the compound in such an amount that the atomic ratio (Al / transition metal) becomes 5 to 10000, preferably 10 to 5000.

The production process of the propylene polymer (A) used in the present invention is not particularly limited except that it is produced using the above-mentioned catalyst, and is obtained by polymerizing propylene by a known method. Can be Further, the polymerization may be performed in two or more stages under different reaction conditions.

Crystal Nucleating Agent (B) The polypropylene resin for an injection molded container according to the present invention may contain a crystal nucleating agent (B) in addition to the propylene polymer (A).

Preferred examples of the crystal nucleating agent (B) include branched olefin polymers such as poly-3-methyl-1-butene. Such a branched olefin polymer may be pre-polymerized and mixed with a propylene polymer, or may be contained as a prepolymer in the propylene polymer (A), for example.

Furthermore, various conventionally known nucleating agents can be used without any particular limitation. For example, phosphates such as sodium-2,2'-methylene-bis (4,6-di-t-butylphenyl) phosphate and sodium-2,2'-methylene-bis (4-t-butylphenyl) phosphate , Also 1,3,2,4-dibenzylidene sorbitol, 1,
3,2,4-di (p-methylbenzylidene) sorbitol, 1,3,
2,4-di (p-ethylbenzylidene) sorbitol, 1,3-p-
Sorbitol compounds such as chlorbenzylidene-2,4-p-methylbenzylidene sorbitol and 1,3,2,4-di (p-chlorobenzylidene) sorbitol can be mentioned.

Further, as the crystal nucleating agent (B), a metal salt of an aromatic carboxylic acid or an aliphatic carboxylic acid, specifically, aluminum benzoate, aluminum pt-butylbenzoate or sodium adipate, Sodium phenecarboxylate, sodium pyrrolecarboxylate and the like can be used. Further, an inorganic compound such as talc can be used.

The nucleating agent (B) as described above is used in an amount of 0.001 to 1 with respect to 100 parts by weight of the propylene polymer (A).
0 parts by weight, preferably 0.01 to 5 parts by weight, particularly preferably 0.1 to 3 parts by weight.

The polypropylene resin containing the crystal nucleating agent (B) as described above can reduce the size of crystal grains and increase the crystallization speed to enable high-speed molding. When a polypropylene resin containing a crystal nucleating agent (B) is used, an injection molded article having excellent heat resistance can be obtained.

Other Components In the polypropylene resin for an injection molded container according to the present invention,
If necessary, for example, conventionally known antioxidants, lubricants,
Additives such as an antistatic agent, an ultraviolet absorber, and a light stabilizer may be added as long as the object of the present invention is not impaired.

[0065]

According to the present invention, when an injection-molded article is manufactured using the polypropylene resin according to the present invention, the transparency is good and the balance between the vertical molding shrinkage and the horizontal molding shrinkage is improved. Since a molded product excellent in heat deformation temperature can be obtained, the molded product has a good shape as designed, and there is little possibility of deformation even if the package contents are heated in a later step. Therefore, a polypropylene resin suitable for manufacturing a cup-shaped container or the like is provided.

[0066]

EXPERIMENTAL EXAMPLES Hereinafter, the present invention will be described with reference to experimental examples, but the present invention is not limited to these experimental examples.

[0067]

Experimental Example 1 A propylene homopolymer [MFR (ASTM D 123) prepared using a metallocene-based olefin polymerization catalyst.
8,230 ° C, load 2.16 kg): 43 g / 10 min, isotactic index (II): 90.0, melting point: 154.4 ° C,
Crystallization temperature: 114.6 ° C., crystallization speed: 996 seconds; hereinafter abbreviated as (PP-1)], and injection molding under the following injection conditions, and square plates (120 m) having different injection molding temperatures.
mx 125 mm, thickness 2 mm). <Injection molding conditions>-Injection molding machine: manufactured by Toshiba Machine Co., Ltd., trade name IS100
G-3A ・ Molding temperature: 180 ° C, 200 ° C, 210 ° C, 240 ° C
Injection pressure: 1000 kg / cm ²・ Holding pressure: 700 kg / cm ²・ Injection speed: 70% ・ Mold temperature: 40 ° C. In addition, the vertical and horizontal molding of the square plate obtained by the above injection molding. Measure the shrinkage (L1, L2) as follows,
The absolute value of the difference in molding shrinkage (LR) was determined by the above-described formula. <Method of measuring molding shrinkage> 100 m above the surface of the above square plate mold
A mark of a cross is placed at the position of the vertex of the square of m × 100 mm, the distance between the vertices of the square in the flow direction of the resin in the mold is M1, and the distance between the vertices of the side in the direction perpendicular to the flow direction is M1. Is M2. The distance between the vertices of the squares in the flow direction of the resin of the cross mark transferred to the surface of the injection square plate molded product is S1, and the distance between the vertices of the sides in the direction perpendicular to the flow direction is S2. The molding shrinkage rates L1 and L2 were calculated by the following equations.

L1 = [(M1-S1) × 100] / M1 L2 = [(M2-S2) × 100] / M2 LR [%] = [(L1-L2) × 100] / L1 It is shown in the table.

The haze (transparency) and the heat distortion temperature (heat resistance) of the formed square plate were measured according to the following test methods. (1) Haze Haze as an index of transparency was measured according to ASTM D1003. (2) Heat deformation temperature (HDT) The heat deformation temperature was determined by conducting a test under the following conditions in accordance with ASTM D-648. <Test conditions> Test piece: 12.7 mm (thickness) x 6.4 mm (width) x 127 mm
(Length) Test load: 4.6 kg / cm ² The results are shown in Table 1.

The melting point, crystallization temperature and crystallization rate of the propylene homopolymer were measured according to the following methods. (1) Melting point, crystallization temperature Using a differential scanning calorimeter (DSC), the propylene homopolymer in a sample pan was heated to 200 ° C. at 20 ° C./min, and then kept at that temperature for 10 minutes. It is cooled to 30 ° C. at a rate of 10 ° C./min. 10 ° C / 30 ° C to 200 ° C
And the endothermic peak appearing at this time is defined as the melting point. When a plurality of peaks appear in any case, the highest peak is taken as the melting point or crystallization temperature. (2) Crystallization rate Using a sample having a thickness of about 0.2 mm formed by a press sheet method, a crystallization rate measuring device MK-701 manufactured by Kotaki Seisakusho.
After the sample was immersed in an oil bath at an oil bath temperature of 125 ° C., the time required for the amount of transmitted light to become の of the amount of transmitted light when crystallization was completed was defined as the crystallization speed.

[0071]

EXPERIMENTAL EXAMPLE 2 In Experimental Example 1, a propylene homopolymer [MFR (ASTM D 1238,230) prepared using a Ziegler-based olefin polymerization catalyst instead of (PP-1).
° C, load 2.16 kg): 44 g / 10 min, isotactic index (II): 96.0, melting point: 163.3 ° C, crystallization temperature: 116.3 ° C, crystallization rate: 520 seconds;
P-2), four types of square plates having different injection molding temperatures were prepared in the same manner as in Experimental Example 1. Hereinafter, haze and heat distortion temperature of the obtained square plate were measured in the same manner as in Experimental Example 1.

Table 1 shows the results.

[0073]

EXPERIMENTAL EXAMPLE 3 In Experimental Example 1, a propylene homopolymer [MFR (ASTM D 1238,230) prepared using a Ziegler-based olefin polymerization catalyst instead of (PP-1).
° C, load 2.16 kg): 2.77 g / 10 min, isotactic index (II): 98.4, melting point: 162.7 ° C, crystallization temperature: 115.0 ° C, crystallization rate: 852 seconds; (Abbreviated as (PP-3)) and the injection molding temperature was 2
Three types of square plates having different injection molding temperatures were prepared in the same manner as in Experimental Example 1, except that the temperature was changed to three types of 00 ° C, 230 ° C, and 260 ° C. Hereinafter, haze and heat distortion temperature of the obtained square plate were measured in the same manner as in Experimental Example 1.

Table 1 shows the results.

[0075]

Experimental Example 4 In Experimental Example 1, a propylene homopolymer [MFR (ASTM D 1238,230) prepared using a metallocene-based olefin polymerization catalyst instead of (PP-1).
° C, load 2.16 kg): 3.4 g / 10 min, isotactic index (II): 95.4, melting point: 155.0 ° C, crystallization temperature: 113.0 ° C, crystallization rate: 1500 seconds; (Abbreviated as (PP-4)) and the injection molding temperature was 2
Three types of square plates having different injection molding temperatures were prepared in the same manner as in Experimental Example 1, except that the temperature was changed to three types of 00 ° C, 230 ° C, and 260 ° C. Hereinafter, haze and heat distortion temperature of the obtained square plate were measured in the same manner as in Experimental Example 1.

Table 1 shows the results.

[0077]

[Table 1]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 5/098 C08K 5/521 5/521 C08L 23/10 C08L 23/10 B65D 1/00 A // B29K 23:00 B29L 22 : 00

Claims (3)

[Claims] 1. A polypropylene resin comprising a propylene polymer (A), wherein the propylene polymer (A) has (i) a melt flow rate (ASTM D 1238, 230 ° C., load 2.16 kg) of 10 to 60 g /
(Ii) isotactic index (I.
I.) is in the range of 85 to 99.5, and (iii) the molding shrinkage of the polypropylene resin molded product in the injection direction (longitudinal direction) of the polypropylene resin is L1, and the direction orthogonal to the injection direction (lateral direction). Where L2 is the molding shrinkage of
The absolute value of the molding shrinkage difference (LR) calculated by the formula LR [%] = [(L1−L2) × 100] / L1 is 10% or less, and (iv) the heat distortion temperature of the polypropylene resin molded product is A polypropylene resin for an injection molded container having a temperature of 115 ° C. or higher. 2. The polypropylene resin for an injection molded container according to claim 1, wherein the propylene polymer (A) is produced using a metallocene olefin polymerization catalyst. 3. The polypropylene resin for an injection molded container according to claim 1, wherein the polypropylene resin contains a nucleating agent (B) in addition to the propylene polymer (A). .