JP2003286377A - Polypropylene resin composition and stretched blow container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene resin composition having excellent stretchability and suitable for manufacturing a stretched blow container having high transparency and rigidity. <P>SOLUTION: The polypropylene resin composition is constituted of a polypropylene resin containing an α-olefin constituent unit and a nucleating agent. The polypropylene resin is characterized in that a melt flow rate is 10-80 (g/10 min), the content of an α-olefin unit is 0.4-5.0 wt.%, a fusion start temperature by DSC analysis is 90-150°C, a fusion completion temperature is 150-175°C and the difference between both temperatures is 30-85°C and preferably comprises a composition constituted of 5-95 wt.% of a propylene homopolymer and 5-95 wt.% of a propylene/α-olefin random copolymer. The stretched blow container molded from this resin composition is suitable as a packaging container because it has high transparency and rigidity and is reduced in wall thickness irregularity. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene resin composition having excellent stretch blow moldability and a stretch blow container obtained therefrom.

[0002]

BACKGROUND OF THE INVENTION Stretch blow containers made of polypropylene resin have been widely used as packaging containers for food and drink because of their excellent heat resistance, surface gloss, strength and rigidity. Since rigidity is particularly important as the physical property of the container, propylene homopolymer has been exclusively used as a raw material resin so far.

In order to manufacture a stretch blow container, a method in which polypropylene resin is melt-injection-molded to once form a preform, then the preform is longitudinally stretched with a stretching rod, and then a pressurized fluid is blown into the preform to laterally stretch is industrially used. Has been adopted as Since the temperature range in which the propylene homopolymer used as the raw material resin can be stretched is narrow, production control becomes difficult in the stretching step in which strict temperature control is performed. Therefore, if the stretching temperature range of the resin can be widened, the temperature can be adjusted more easily in the summer and winter, and at the same time, the production of a thin and uniform container can be facilitated.

Further, the stretch blow container made of polypropylene resin is not sufficiently transparent as compared with the container made of polyester resin. Therefore, if the transparency of the polypropylene resin container is improved, it is expected that the range of its application can be further expanded.

[0005]

Therefore, an object of the present invention is to provide a polypropylene resin composition which is excellent in stretchability and is suitable for producing a stretch blow container having high transparency and rigidity. Another object of the present invention is to provide a polypropylene resin stretch-blown container having high transparency and rigidity, and having less uneven thickness.

[0006]

That is, the present invention provides α-
A resin composition comprising a polypropylene resin (A) containing an olefin structural unit and a nucleating agent (B),
The polypropylene resin (A) has (1) a melt flow rate (MFR) of 5 to 80 (g / 10 minutes),
(2) The content of the α-olefin unit is 0.4 to 5.0% by weight, and (3) the melting start temperature (Ti) and the melting end temperature (Tf) at the melting peak measured by DSC analysis.
And 90 to 150 ° C. and 150 to 175 ° C., respectively, and (4) a polypropylene resin composition in which the difference between the melting start temperature (Ti) and the melting end temperature (Tf) is 30 to 85 ° C. .

A preferred embodiment of the polypropylene resin (A) is a composition comprising 5 to 95% by weight of a propylene homopolymer (A1) and 5 to 95% by weight of a propylene / α-olefin random copolymer (A2). I can list things. The propylene / α-olefin random copolymer (A2) preferably has a content of α-olefin units in the range of 0.5 to 5.0% by weight,
As a specific example of the copolymer, a propylene / ethylene random copolymer or a propylene / ethylene / 1-butene ternary random copolymer is desirable. Since such a polypropylene resin composition has good stretchability, it can be suitably used for producing a stretch blow container.

The present invention also relates to a stretch blow container made of such a polypropylene resin composition, and since the container has high transparency and rigidity, it is suitable as a packaging container.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Next, the polypropylene resin composition according to the present invention and the stretch blow container manufactured using the same will be specifically described.

Polypropylene Resin (A) The polypropylene resin (A) usable in the present invention contains propylene and α-olefin as its constituent units and has the properties and physical properties described below.

(Properties and Properties of Resin) First, ASTM D
According to -1238, the melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg is 5 to 8
0 (g / 10 minutes), preferably 8 to 60 (g / 10
Minutes), more preferably 10 to 50 (g / 10 minutes). The polypropylene resin having an MFR value in the above range maintains a good balance among injection moldability, stretch blow moldability and mechanical strength of a molded product.

Next, the ratio of the monomer units constituting the polypropylene resin is in the following range. That is, the content of the propylene unit is 95.0 to 99.6% by weight, preferably 96.0 to 99.5% by weight, and more preferably 97.
0-99.2% by weight, and the content of α-olefin units is 0.4-5.0% by weight, preferably 0.5-4.
It is 0% by weight, more preferably 0.8 to 3.0% by weight. Here, the total amount of propylene units and α-olefin units is 100% by weight, and the content of each unit can be measured by, for example, infrared absorption spectrum analysis. Such a monomer-structured polypropylene resin has an excellent balance of transparency, rigidity, and stretch blowability.

Furthermore, when the melting curve of this polypropylene resin (A) is measured by analysis using a differential scanning calorimeter (DSC), the melting peak appears first and the melting start temperature (Ti) and the melting peak end. The melting end temperature (Tf) is 90 to 150 ° C. and 150 to 175, respectively.
C, preferably 100-150 C and 155-1 respectively
75 ° C, more preferably 120-150 ° C and 1 each
It is in the range of 60 to 165 ° C. In addition, the melting start temperature (T
The temperature difference between i) and the melting end temperature (Tf) is 30 to 85.
° C, preferably 35 to 70 ° C, more preferably 40 to 6
It is in the range of 0 ° C.

The analysis by DSC is performed by once melting the sample under a nitrogen gas inflow, cooling it, and then heating it again at a temperature rising rate of 10 ° C./min. The melting start temperature (Ti) and the melting end temperature (Tf) are read from the chart in which the melting peak of the polypropylene resin measured during the temperature rising process is recorded.

Here, the melting start temperature (Ti) is the intersection of the straight line extending the low temperature side baseline to the high temperature side and the tangent line drawn on the low temperature side curve of the melting peak at the point where the gradient becomes maximum. It is represented by the temperature shown. In addition, the melting end temperature (T
f) is represented by the temperature indicated by the intersection of the straight line extending the high temperature side baseline to the low temperature side and the tangent line drawn on the high temperature side curve of the melting peak at the point where the slope is maximum. In addition,
When there are a plurality of melting peaks, the melting start temperature corresponding to the first melting peak is Ti of the resin, and the melting end temperature corresponding to the last melting peak is the Tf of the resin.

The temperature difference (° C.) between the melting start temperature (Ti) and the melting end temperature (Tf) of the melting peak is also referred to herein as the melting peak width, and the temperature corresponding to the apex of the melting peak is the melting point. I am calling. Since the melting peak reflects the melting behavior of the polypropylene resin, a wide melting peak width means a wide stretchable temperature range. Therefore, when the width of the melting peak is within the above-mentioned temperature range, the polypropylene resin is excellent in stretch blow moldability.

Further, this polypropylene resin (A)
Is the number average molecular weight (Mw) of its weight average molecular weight (Mw).
The ratio to n), that is, the value of Mw / Mn is preferably 1.5 to 7.0, and more preferably 2.0 to 5.0. The value of Mw / Mn is an index showing the width of the molecular weight distribution, and when the value is within the above range, the balance between stretch blow moldability and transparency is excellent.

Each value of Mw and Mn is measured by gel permeation chromatography (GPC) method. To give an example of the measuring method, Waters
Using a 150C type machine manufactured by Polymer Laboratories, a column Plmixed B manufactured by Polymer Laboratories was attached, and the measurement temperature was set to 1
A sample having a polymer concentration of 0.15% by weight is 400 μm at 35 ° C. and o-dichlorobenzene is used as a solvent.
l is supplied and measurement is performed. The values of Mw and Mn are calculated using a calibration curve prepared using standard polystyrene.

(Structure of Resin) The polypropylene resin (A) according to the present invention has a propylene unit and an α-olefin unit as its monomer structure, and the kind thereof is particularly limited as long as it satisfies the above-mentioned properties and physical properties. It is not limited. A preferred specific example of such a polypropylene resin is a composition composed of a propylene homopolymer (A1) and a propylene / α-olefin random copolymer (A2).

The propylene homopolymer (A1) preferably has a composition ratio of 5 to 5 in the composition.
95% by weight, more preferably 20 to 80% by weight, further preferably 30 to 50% by weight, and the propylene / α-olefin random copolymer (A2) is preferably 5 to 95% by weight.
%, More preferably 20 to 80% by weight, further preferably 50 to 70% by weight. Here, the total amount of both polymers is 100% by weight.

(Propylene homopolymer (A1)) As the propylene homopolymer, the MFR value measured under the same conditions as described above is preferably 5 to 80 (g / 10 minutes), more preferably 8 to 60 ( g / 10 min) of the polymer and the melting point measured by DSC analysis is preferably from 145 to 167 ° C., more preferably from 155-1.
It is a polymer in the range of 65 ° C.

(Propylene / α-olefin random copolymer (A2)) The propylene / α-olefin random copolymer has an α-olefin content of preferably 0.5 to 5.0% by weight, More preferably 1.0 to
It is a polymer of 4.5% by weight. The MFR value measured under the same conditions as described above is preferably 5 to 80 (g /
10 minutes), more preferably 8 to 60 (g / 10 minutes), and when such a copolymer is used, a resin composition having excellent stretch blow moldability can be obtained. The melting point measured by DSC analysis is preferably 120 to 160 ° C,
More preferably, it is in the range of 130 to 150 ° C., and when such a copolymer is used, a polypropylene resin composition having a high heat resistance of the container and a wide stretching temperature range during molding can be obtained.

As the α-olefin, ethylene or an α-olefin having 4 to 20 carbon atoms is preferable, and specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradodecene, 1-hexadodecene, 1-octadodecene, 1-eicosene and the like can be mentioned. Among these, ethylene and 4 to 4 carbon atoms
The α-olefin of 8 is preferable, and ethylene is particularly preferable.

Specific examples of the propylene / α-olefin random copolymer include propylene / ethylene random copolymer, propylene / 1-butene random copolymer,
Propylene / 1-pentene random copolymer, propylene / 1-hexene random copolymer, propylene / 1-
Octene random copolymer, propylene / ethylene / 1
-Butene random terpolymers may be mentioned.
Among these, propylene / ethylene random copolymer and propylene / ethylene / 1-butene random terpolymer are preferable.

(Method for producing resin) Such a propylene homopolymer and a propylene / α-olefin random copolymer are prepared in the presence of an olefin stereoregular polymerization catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. Then, propylene can be produced by polymerizing propylene in the presence of other α-olefin, if necessary. As an example of the polymerization catalyst, mention is made of a catalyst system comprising (A) a solid catalyst component containing magnesium, titanium, halogen and an electron donor as essential components, (B) an organoaluminum compound, and (C) an electron donor. You can Next, each component of this catalyst system will be described.

The magnesium compound used for the synthesis of the solid catalyst component may be a magnesium compound having a reducing ability such as an alkyl magnesium compound, an alkyl magnesium halide compound or a magnesium hydride compound, or a magnesium halide compound. Alternatively, a magnesium compound having no reducing ability such as an alkoxy magnesium halide compound, an allyloxy magnesium halide compound, or an alkoxy magnesium compound may be used. Among these magnesium compounds, magnesium compounds having no reducing property are preferable, and halogen-containing magnesium compounds such as magnesium chloride, alkoxy magnesium chloride, and aryloxy magnesium chloride are particularly preferable.

Examples of the titanium component include a tetravalent titanium compound represented by the following formula. Ti (OR) _n X _4-n (wherein R is a hydrocarbon group, X is a halogen atom, and n is a numerical value of 0 ≦ n ≦ 4)

As an example of such a titanium compound,
We can mention compound. (1) TiCl_Four, TiBr_Four, TiI_FourTetraha etc.
Trogened titanium compound (2) Ti (OCH_Three) Cl_Three, Ti (OC_TwoH₅) C
l_Three, Ti (O-n-C _FourH₉) Cl_Three, Ti (OC_Two
H₅) Br_Three, Ti (O-iso-C_FourH₉) Br_Threeetc
Trihalogenated alkoxy titanium compounds (3) Ti (OCH_Three)_TwoCl_Two, Ti (OC_TwoH₅)
_TwoCl_Two, Ti (O-n-C_FourH₉)_TwoCl_Two, Ti
(OC_TwoH₅)_TwoBr_TwoDialkoxy dialkoxy such as
Titanium compound

(4) Ti (OCH_Three)_ThreeCl, Ti (O
C_TwoH₅)_ThreeCl, Ti (O-n-C _FourH₉)_ThreeCl,
Ti (OC_TwoH₅)_ThreeMono halogenated trials such as Br
Coxititanium compound (5) Ti (OCH_Three)_Four, Ti (OC_TwoH₅)_Four, T
i (O-n-C_FourH₉) _Four, Ti (O-iso-C_FourH
₉)_Four, Ti (O-2-ethylhexyl)_FourTetra etc.
Alkoxy titanium compound

As the electron donor, alcohols, phenols, ketones, aldehydes, carboxylic acids,
Examples thereof include organic acid halides, organic acid or inorganic acid esters, ethers, acid amides, acid anhydrides, nitrogen-containing cyclic compounds such as ammonia, amines, nitriles and isocyanates, and oxygen-containing cyclic compounds. Among these, carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, carboxylic acid halides, alcohols and ethers can be preferably used.

As a method for preparing a solid catalyst component from the above components, for example, a solution of a magnesium compound is reacted with a solution titanium compound, preferably in the presence of an electron donor to precipitate a solid magnesium-titanium complex. The method of making it possible can be mentioned.

The organoaluminum compound used with the solid catalyst component is one having at least one Al-carbon bond in the molecule. Next, a typical example thereof is shown by a general formula. _{^{R 1 m AlY 3-m R}} 2 R 3 Al-O-Al R 4 R 5 ( ^wherein, R 1 to R ⁵ is a 1-8 hydrocarbon group with a carbon number, they are the same to each other May be present or different. Y represents a halogen atom, a hydrogen atom or an alkoxy group, and m is a number represented by 2 ≦ m ≦ 3.)

Specific examples of the organoaluminum compound include trialkylaluminums such as triethylaluminum, triisobutylaluminum and trihexylaluminum, dialkylaluminum hydrides such as diethylaluminum hydride and diisobutylaluminum hydride, and mixtures of triethylaluminum and diethylaluminum chloride. Examples thereof include a mixture of a trialkylaluminum and a dialkylaluminum halide, and an alkylalumoxane such as tetraethyldialumoxane and tetrabutyldialumoxane.

Of these organoaluminum compounds, trialkylaluminums, mixtures of trialkylaluminums and dialkylaluminum halides, alkylalumoxanes are preferred, especially triethylaluminum, triisobutylaluminum, mixtures of triethylaluminum and diethylaluminum chloride,
Alternatively, tetraethyl dialumoxane is preferred.

The following compounds can be used as examples of the external electron donor used together with the solid catalyst component and the organoaluminum compound. (1) A compound containing a nitrogen atom such as piperidine, pyrrolidine, pyridine and amine (2) A compound containing a sulfur atom such as thiophenol, thiophene and mercaptan (3) An oxygen atom such as furan, pyran, dioxane, ether and ketone compounds containing (4) general formula _{R n Si (OR ') 4} -n ( wherein, R
And R ′ are hydrocarbon groups, and n is a numerical value of 0 <n <4).

As for the composition ratio of the catalyst component, the molar ratio of the organoaluminum compound to the Ti atom (mol) in the solid catalyst component is in the range of 5 to 1000, and the external electron donor is the molar ratio to the organoaluminum compound (mol). The ratio is preferably in the range of 0.002 to 0.5.

The polymerization reaction can be carried out by liquid phase polymerization or gas phase polymerization, in which case any of batch system, semi-continuous system and continuous system can be adopted. The polymerization temperature is usually −50 to 100 ° C., preferably 0 to 90 ° C. when carrying out the slurry polymerization, and usually 0 to when carrying out the solution polymerization method.
It is desirable that the temperature is 250 ° C, preferably 20 to 200 ° C. When carrying out the gas phase polymerization method, the polymerization temperature is
It is usually 0 to 120 ° C., preferably 20 to 100 ° C. The polymerization pressure is usually from atmospheric pressure to 100 (kg
/ Cm ² ), preferably atmospheric pressure to 50 (kg / cm ² ). The polymerization reaction can also be carried out in two or more stages under different reaction conditions.

The propylene homopolymer and the propylene / ethylene random copolymer may be polymerized in separate polymerization apparatuses, and then the two may be mixed and, if necessary, melt-kneaded may be added. It is also possible to employ, for example, a multistage polymerization method in which a propylene homopolymer is produced in the first stage and then a propylene / ethylene random copolymer is polymerized in the second stage using a series of polymerization apparatuses.
Of these production methods, the latter multi-stage polymerization method is preferably adopted.

Nucleator (B) In the polypropylene resin composition of the present invention, a nucleator is blended with the above polypropylene resin in order to improve transparency and rigidity. As such a nucleating agent, a sorbitol compound, an organic phosphoric acid ester compound, a dicarboxylic acid and its metal salt, or a branched olefin polymer can be used. Next, each nucleating agent will be described.

(Sorbitol Nucleating Agent) As the sorbitol nucleating agent, the following compounds can be exemplified. (1) 1,3,2,4-dibenzylidene sorbitol,
1,3-benzylidene-2,4-p-methylbenzylidene sorbitol, 1,3-benzylidene-2,4-p-
Ethylbenzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-benzylidene sorbitol,
1,3-p-ethylbenzylidene-2,4-benzylidenesorbitol, 1,3-p-methylbenzylidene-
2,4-p-ethylbenzylidene sorbitol, 1,3
-P-Ethylbenzylidene-2,4-p-methylbenzylidene sorbitol

(2) 1,3,2,4-di (p-methylbenzylidene) sorbitol, 1,3,2,4-di (p-
Ethylbenzylidene) sorbitol, 1,3,2,4-
Di (pn-propylbenzylidene) sorbitol,
1,3,2,4-di (pi-propylbenzylidene)
Sorbitol, 1,3,2,4-di (pn-butylbenzylidene) sorbitol, 1,3,2,4-di (p-
s-Butylbenzylidene) sorbitol, 1,3,2
4-di (pt-butylbenzylidene) sorbitol,
1,3,2,4-di (p-methoxybenzylidene) sorbitol, 1,3,2,4-di (p-ethoxybenzylidene) sorbitol

(3) 1,3-benzylidene-2,4-p
-Chlorobenzylidene sorbitol, 1,3-p-chlorobenzylidene-2,4-benzylidene sorbitol,
1,3-p-chlorobenzylidene-2,4-p-methylbenzylidene sorbitol, 1,3-p-chlorobenzylidene-2,4-p-ethylbenzylidene sorbitol, 1,3-p-methylbenzylidene-2,4 -P-chlorobenzylidene sorbitol, 1,3-p-ethylbenzylidene-2,4-p-chlorobenzylidene sorbitol, 1,3,2,4-di (p-chlorobenzylidene)
Sorbitol

Among them, especially 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di (p-
Methylbenzylidene) sorbitol or 1,3-p-
Chlorbenzylidene-2,4-p-methylbenzylidene sorbitol is preferred.

(Organic Phosphate Ester Nucleating Agent) Examples of the organic phosphate ester nucleating agent include compounds represented by the following general formula (1) or (2).

[Chemical 1]

[0044]

[Chemical 2]

In the above formula, R ¹ is a divalent hydrocarbon group having 1 to 10 carbon atoms, R ² and R ³ are hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and R ² And R ³ may be the same or different, M is a metal atom having a valence of 1 to 3, n is an integer of 1 to 3, and m is 1 or 2.

Specific examples of the compound represented by the general formula (1) include sodium-2,2'-methylene-bis (4,4).
6-di-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis (4,6-di-t-)
Butylphenyl) phosphate, lithium-2,2 '
-Methylene-bis- (4,6-di-t-butylphenyl) phosphate, lithium-2,2'-ethylidene-bis (4,6-di-t-butylphenyl) phosphate, sodium-2 , 2'-ethylidene-bis (4-
i-Propyl-6-t-butylphenyl) phospha-
Lithium-2,2'-methylene-bis (4-methyl-6-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis (4-ethyl-6-t-butylphenyl) Phosphate,

Sodium-2,2'-butylidene-bis (4,6-di-methylphenyl) phosphate, sodium-2,2'-butylidene-bis (4,6-di-t)
-Butylphenyl) phosphate, sodium-2,
2'-t-octylmethylene-bis (4,6-di-methylphenyl) phosphate, sodium-2,2'-
t-octylmethylene-bis (4,6-di-t-butylphenyl) phosphate, calcium-bis- (2,
2'-methylene-bis (4,6-di-t-butylphenyl) phosphate), magnesium-bis [2,2 '
-Methylene-bis (4,6-di-t-butylphenyl)
Phosphate], barium-bis [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate], sodium-2,2′-methylene-bis (4
-Methyl-6-t-butylphenyl) phosphate,
Sodium-2,2'-methylene-bis (4-ethyl-
6-t-butylphenyl) phosphate,

Sodium-2,2'-ethylidene-bis (4-m-butyl-6-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis (4,4)
6-di-methylphenyl) phosphate, sodium-2,2'-methylene-bis (4,6-di-ethylphenyl) phosphate, potassium-2,2'-ethylidene-bis (4,6-) Di-t-butylphenyl) phosphate, calcium-bis [2,2'-ethylidene-bis (4,6-di-t-butylphenyl) phosphite
], Magnesium-bis [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphine
], Barium-bis [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphine
], Aluminum-tris [2,2′-methylene-bis (4,6-di-t-butylfel) phosphate]
And aluminum-tris [2,2'-ethylidene-
Bis (4,6-di-t-butylphenyl) phosphine
And a mixture of two or more thereof.

A hydroxyaluminum phosphate compound represented by the general formula (2) is also an organic phosphoric acid ester compound which can be used, in which both R ² and R ³ are t.
A compound represented by the general formula (3) which is a -butyl group (t-Bu) is preferable. Here, R ¹ is 2 having 1 to 10 carbon atoms.
It is a valent hydrocarbon group, and m is 1 or 2.

[Chemical 3]

A particularly preferred organic phosphate compound is a compound represented by the general formula (4). Where R
¹ is a methylene group or an ethylidene group. Specifically, hydroxyaluminum-bis [2,2'-methylene-bis (4,6-di-t-butyl) phosphate], and hydroxyaluminum-bis [2,2 '.
-Ethylidene-bis (4,6-di-t-butyl) phosphate].

[0051]

[Chemical 4]

(Dicarboxylic acid and metal salt thereof) Aliphatic dicarboxylic acid having 4 to 12 carbon atoms, for example, succinic acid,
Glutaric acid, adipic acid, suberic acid, sebacic acid,
And their Li, Na, Mg, Ca, Ba, Al salt etc. can be used.

Examples of aromatic carboxylic acids, aromatic dicarboxylic acids, and metal salts thereof include benzoic acid, p-isopropylbenzoic acid, ot-butylbenzoic acid, pt-butylbenzoic acid, Monophenylacetic acid, diphenylacetic acid, phenyldimethylacetic acid, phthalic acid and their Li, Na, Mg, Ca, Ba, Al salts can be used.

(Branched α-Olefin Polymer) Branched α
-Examples of olefin polymers include 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4, 4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3
Examples thereof include homopolymers of -ethyl-1-hexene, copolymers thereof, and copolymers thereof with other α-olefins. Particularly, a polymer of 3-methyl-1-butene is preferable.

[0055] The polypropylene resin composition according to the tree fat group formed product present invention is basically formed of a polypropylene resin and a nucleating agent.
The mixing ratio of the nucleating agent is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 0.5 parts by weight, based on 100 parts by weight of the polypropylene resin. When the nucleating agent is added within this range, the obtained resin composition exhibits good transparency and high rigidity.

This resin composition contains, if necessary, an antioxidant, a heat stabilizer, a weather stabilizer, an antistatic agent, a hydrochloric acid absorbent, an antifogging agent, within a range not departing from the object of the present invention.
Lubricants, slip agents, dyes, pigments, natural oils, synthetic oils, waxes, fillers and the like can be added.

As the antioxidant, known antioxidants can be used. Specifically, a hindered phenol type compound, a sulfur type compound, a lactone type compound, an organic phosphite type compound, an organic phosphonite type compound, or a combination of several kinds thereof can be used.

Examples of the lubricant include sodium, calcium and magnesium salts of saturated or unsaturated fatty acids such as lauric acid, palmitic acid, oleic acid and stearic acid, which may be used alone or in admixture of two or more. Can be used. The compounding amount of the lubricant is usually 0.1 to 3 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the polypropylene resin.

As the slip agent, an amide of a saturated or unsaturated fatty acid such as lauric acid, palmitic acid, oleic acid, stearic acid, erucic acid or hebenic acid, or these bisamides can be used. Among them, erucic acid amide And ethylenebis stearamide are preferred. The blending amount is 100% polypropylene resin.
The range of 0.01 to 5 parts by weight is preferable with respect to parts by weight.

In the production of the resin composition, first, a polypropylene resin, preferably a mixture of a propylene homopolymer and a propylene / α-olefin random copolymer, is added to a nucleating agent and, if necessary, an additive such as an antioxidant. And mix using a Henschel mixer, a V-type blender, a tumbler blender, a ribbon blender and the like. afterwards,
By melt-mixing using a single-screw extruder, a multi-screw extruder, a kneader, a Banbury mixer, etc., a composition in which the respective components are uniformly dispersed and mixed can be obtained.

[0061] Polypropylene resin kettle rolled Shin Bed B over container present invention is a container obtained by injection stretch blow molding the resin composition.

Explaining the concrete manufacturing method, first, a polypropylene resin composition is melted and injection-molded in a mold to form a preform. Then, while the preform is in a molten state or a softened state, or after the preform is once solidified and then reheated, the preform is forcibly longitudinally stretched using a stretching rod or the like. Then, by pressurizing a pressurized fluid into the preform, the preform is stretched in the lateral direction and formed into a container shape.

The melt injection temperature of the polypropylene resin composition is usually in the range of 180 to 270 ° C. The longitudinal stretching of the preform has a temperature of 110 to 150 ° C. and a magnification of 1.
It is usually carried out at 5 to 4.0 times, and the subsequent transverse stretching is usually carried out at a temperature of 110 to 165 ° C. and a magnification of 1.5 to 4.0 times.

Since the polypropylene resin composition of the present invention is excellent in stretchability during molding, it can be stretch-molded in a wide temperature range, and the thickness of the obtained container is thin and thin, and is transparent. Excellent in rigidity and rigidity. Further, this resin composition is excellent in food hygiene and easy to incinerate after use. Therefore, by utilizing its characteristics, it can be suitably used as a container for foods, seasonings, drinking water, cosmetics and the like.

[0065]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples.

The physical properties of the resins used in the examples and comparative examples, the physical properties of the molded containers, and the performance evaluation were performed according to the following methods. (1) Cut out a test piece for measuring rigidity from a rigid container, and use ASTM D-7
Bending rigidity (MPa) is measured according to the method of 90,
The rigidity of the container was evaluated based on this rigidity.

(2) Melt Flow Rate (MFR) According to ASTM D-1238, 230 ° C., load 2.
It was measured under the condition of 16 kg.

(3) Transparency (haze) A test piece for measuring haze was cut out from the container and A
It measured based on STM D-1003.

(4) Melting peak width and melting point A differential scanning calorimeter (DSC) was used to load 10 mg of a sample into a measurement container which had been replaced with nitrogen, and first heated to 240 ° C. to melt the sample, and then 10 ° C. The sample is cooled by lowering the temperature at a rate of / min. The temperature of this sample is again raised at a rate of 10 ° C./minute, and a DSC chart is obtained from the melting curve measured at that time.

The melting point of the obtained melting curve is defined as the intersection of the straight line obtained by extending the low temperature side baseline to the high temperature side and the tangent line drawn to the curve on the low temperature side of the melting peak at the point where the gradient becomes maximum. Ti). On the other hand, the temperature at the intersection of the straight line extending the high temperature side baseline to the low temperature side and the tangent line drawn at the point where the gradient of the high temperature side of the melting peak has the maximum was taken as the melting end temperature (Tf). Also, melting start temperature (Ti)
The temperature difference (° C.) between the melting point and the melting end temperature (Tf) was defined as the “melting peak width”, and the peak of the melting peak was displayed as the melting point.

(5) From the container manufactured by stretch blow molding to the upper part,
The sample was cut into the central part and the lower part, and the wall thickness was measured at each site. The deviation 2σ (%) of the thickness of each site is displayed as the thickness unevenness.

Example 1 <Production of Propylene Homopolymer> [Preparation of Solid Titanium Catalyst Component [A]] 7.14 kg (75 mol) of anhydrous magnesium chloride, 37.5 l of decane and 35.1 l of 2-ethylhexyl alcohol. (225 mol) was heated and reacted at 130 ° C. for 2 hours to form a uniform solution. Then, 1.67 kg of phthalic anhydride in this solution
(11.3 mol) was added, and the mixture was stirred and mixed at 130 ° C. for 1 hour to dissolve phthalic anhydride in the homogeneous solution.

After cooling the homogeneous solution thus obtained to room temperature, titanium tetrachloride 20 kept at -20.degree.
The total amount was added dropwise to 01 (180 mol) over 1 hour. After the dropping, the temperature of the obtained solution is 110 for 4 hours.
The temperature was raised to 110 ° C., and when it reached 110 ° C., 5.031 (18.8 mol) of diisobutyl phthalate was added. The mixture was stirred for another 2 hours at the above temperature. After the completion of the reaction for 2 hours, the solid part was collected by hot filtration, and the solid part was
After resuspended with 751 of titanium tetrachloride TiC1 _4, 2 hours again 110 ° C., heating was performed for the reaction. After completion of the reaction, the solid part is collected again by hot filtration and then at 110 ° C.
Washed with decane and hexane. This washing was performed until no titanium compound was detected in the washing liquid.

The solid titanium catalyst component synthesized as described above was obtained as a hexane slurry. A part of this catalyst was sampled and dried, and the dried product was analyzed and found to have a composition of 2.5 wt% titanium, 58 wt% chlorine, 18 wt% magnesium and 13.8 wt% diisobutylphthalate. It was

[Polymerization] A catalyst volume of 400 m was added to a 2001-volume autoclave which had been sufficiently replaced with nitrogen.
g, and then add triethylaluminum 3.5 ml, dicyclohexyldimethoxysilane 5 ml
Was added. 50 kg of liquefied propylene, and 9
0 liter of hydrogen was charged, and polymerization was carried out at 70 ° C. for 60 minutes under a pressure of 3.0 to 3.5 MPa. After completion of the polymerization, methanol was added to stop the polymerization, and unreacted propylene was purged to obtain a propylene homopolymer (PP-1). It was dried under vacuum at 80 ° C. for 6 hours.

The resulting propylene homopolymer (PP-
1) has MFR (230 ° C) of 30 (g / 10 minutes), M
The w / Mn was 5.0, and the n-decane-soluble content was 0.8% by weight.

<Production of Propylene-Ethylene Random Polymer (PP-2)> In the above-mentioned production of propylene homopolymer, 50 kg of liquid propylene and 0.8 kg of ethylene are pressed into the autoclave instead of 300 liters of liquid propylene. Was produced in the same manner as in the production of propylene homopolymer to produce a copolymer.

The propylene / ethylene random copolymer (PP-2) thus obtained had an MFR (230 ° C.) of 25 (g).
/ 10 min), and the ethylene content was 4.0% by weight.

<Production of Composition> 40 parts by weight of the propylene homopolymer (PP-1) obtained by the above method, 60 parts by weight of the propylene / ethylene random copolymer (PP-2), as a nucleating agent. Dibenzylidene sorbitol 250
0 ppm, and tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane (product of Nippon Ciba-Geigy, trade name Irganox 1010) 100 as an antioxidant.
0 ppm was mixed with a Henschel mixer. Then put into a twin-screw extruder (65 mmφ) and the resin temperature is 200 ° C.
And kneading was carried out under the condition of screw rotation speed of 200 rpm to obtain pellets of the composition.

The composition obtained had an MFR of 28 (g / 1
0 min), Mw / Mn of 5.0, melting point of 145 ° C. and 1
The melting peak width was 65 ° C and 45 ° C.

<Production of Preform for Stretch Blow Container>
The polypropylene resin composition pellets were supplied to an injection stretch blow molding machine (Nissei resin product trade name FE160), and the container (5
A preform for (00 ml volume) was molded.

<Production of Stretch Blow Container> Next, the preform was transferred to a stretch blow molding machine (product of Frontier Co., Ltd., trade name EFB2000), and the preform was heated to 135 ° C. in the mold. After that, it was stretched 2.8 times in the longitudinal direction using a stretching rod.

Then, 10 (kg
F / cm ² ) of pressurized air was blown into the preform to stretch it laterally 2.9 times, expand the preform into the shape of a bottle container having a capacity of 500 ml, and hold it for 10 seconds. afterwards,
Cool the container by injecting 5 ° C cooling air into the container,
The mold was opened and the bottle container was taken out.

The thickness of the obtained bottle container is about 1 mm,
The physical properties of the container and the unevenness of the wall thickness were measured, and the results are shown in Table 1.

(Example 2) Example 2 except that the mixing ratio of the propylene homopolymer (PP-1) and the propylene / ethylene random copolymer (PP-2) was changed to 50:50. The same procedure as in 1 was performed to obtain a composition pellet.

The composition has an MFR of 30 (g / 10 minutes), M
The w / Mn was 5.1, the melting points were 145 ° C and 160 ° C, and the melting peak width was 42 ° C. Further, for the obtained bottle container, the physical properties and thickness unevenness thereof are measured,
The results are also shown in Table 1.

Comparative Example 1 Propylene homopolymer (PP
-1) 100 parts by weight of dibenzylidene sorbitol 2500 ppm as a nucleating agent, and tetrakis [methylene-3- (3 ', 5'-di-t-] as an antioxidant.
Butyl-4'-hydroxyphenyl) propionate]
Methane (product of Nippon Ciba-Geigy, trade name Irganox 1010) 1000 ppm was added and mixed using a Henschel mixer. Then twin-screw extruder (65mm
φ) and kneaded at a resin temperature of 200 ° C. and a screw rotation speed of 200 rpm to obtain pellets of the composition.

The MFR of the composition was 30 (g / 10
Min), Mw / Mn was 5.0, the melting point was 160 ° C, and the melting peak width was 25 ° C. Then, a stretch-blown container was produced from this composition in the same manner as in Example 1, and its physical properties and uneven thickness were measured, and the results are shown in Table 1.

Comparative Example 2 100 parts by weight of a propylene / ethylene random copolymer (PP-2), 2500 ppm of dibenzylidene sorbitol as a nucleating agent, and tetrakis [methylene-3-3 as an antioxidant.
(3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane (product of Nippon Ciba-Geigy, trade name Irganox 1010) 1000 ppm
Was added and mixed using a Henschel mixer. Then, supply to a twin-screw extruder (65 mmφ) to obtain a resin temperature of
Kneading was performed under the conditions of ° C and a screw rotation speed of 200 rpm to obtain pellets.

The MFR of the obtained composition was 28 (g / 10
Min), Mw / Mn was 5.0, the melting point was 145 ° C., and the melting peak width was 25 ° C. Then, a stretch-blown container was produced from this composition in the same manner as in Example 1, and its physical properties and thickness unevenness were measured, and the measurement results are shown in Table 1.

(Comparative Example 3) A composition pellet was obtained in the same manner as in Example 1 except that dibenzylidene sorbitol as a nucleating agent was not added. A stretch-blown container was produced from this composition in the same manner as in Example 1, and its physical properties and uneven thickness were measured, and the measurement results are shown in Table 1.

[0092]

[Table 1]

* Melting point: The temperature corresponding to the apex of the melting peak was read from the DSC chart, and the temperature was taken as the melting point. When two melting points are displayed, it means that there are two melting peaks. ** Melting peak width: The value obtained by subtracting the melting start temperature (Ti) from the melting end temperature (Tf) was defined as the melting peak width (° C).

[0094]

The polypropylene resin composition of the present invention is
Since it exhibits excellent stretchability and has a wide stretching temperature range, temperature control during stretch blow molding is easy, and uniform stretching is possible, so that a container with less unevenness in thickness and thickness can be manufactured. Furthermore, the obtained container has good transparency, high rigidity, and excellent mechanical strength. Therefore, the container is suitable as a container for food and drink, cosmetics, pharmaceuticals, and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroki Aso             580-30 Nagaura, Sodegaura, Chiba Prefecture             Within Land Polymer F-term (reference) 3E033 BA16 CA05 CA07 CA18 CA20                       FA03                 4J002 BB12X BB14W EC056 EF066                       EF096 EF116 EG056 EG076                       EG106 EH126 EW046 FD206                       GG01

Claims (6)

[Claims] 1. A resin composition comprising a polypropylene resin (A) containing an α-olefin structural unit and a nucleating agent (B), wherein the polypropylene resin (A) comprises (1)
Melt flow rate (MFR) is 5-80 (g / 10
And the content of (2) α-olefin unit is 0.
4 to 5.0% by weight, and (3) the melting start temperature (Ti) and the melting end temperature (Tf) at the melting peak measured by DSC analysis are 90 to 150 ° C. and 150 to 1, respectively.
Exists in the range of 75 ° C., and (4) melting start temperature (T
The polypropylene resin composition, wherein the difference between i) and the melting end temperature (Tf) is 30 to 85 ° C. 2. The polypropylene resin (A) comprises 5 to 95% by weight of a propylene homopolymer (A1) and 5 to 9 of a propylene / α-olefin random copolymer (A2).
The polypropylene resin composition according to claim 1, wherein the polypropylene resin composition comprises 5% by weight. 3. The propylene / α-olefin random copolymer (A2), wherein the α-olefin unit content is 0.5 to 5.0% by weight. The polypropylene resin composition described. 4. The propylene / α-olefin random copolymer (A2) is a propylene / ethylene random copolymer or a propylene / ethylene / 1-butene ternary random copolymer. Item 4. The polypropylene resin composition according to Item 2 or 3. 5. The polypropylene resin composition according to any one of claims 1 to 4, wherein the resin composition is used for producing a stretch blow container. 6. A stretch blow container comprising the polypropylene resin composition according to any one of claims 1 to 4.