JP3385099B2 - Polypropylene film and sheet - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to a polypropylene-based film and sheet which is suitably used as a packaging material for industrial parts, has good moldability and appearance, and is excellent in rigidity, water vapor barrier property and heat resistance. [0002] Polypropylene films and sheets are lightweight, transparent, mechanically strong, heat resistant, chemically resistant,
Excellent in oil resistance, bending fatigue resistance, etc., and widely used as various packaging materials. In recent years, with the advancement of functions and cost reduction of these film products, there is a strong demand for improved properties of materials. Among these properties, as a method for improving rigidity, a method of adding a nucleating agent such as a metal salt of a carboxylic acid, a dibenzylidene sorbitol derivative, or a filler such as talc (Japanese Patent Publication No. 39-1809, JP And a method using polypropylene having a wide molecular weight distribution (JP-A-56-2307,
JP-A-59-172507 and JP-A-62-195007) have been proposed. As methods for improving rigidity and water vapor barrier properties, methods for increasing the stereoregularity of polypropylene (for example, JP-A-4-202505, JP-A-4-202510, etc.), and methods of blending petroleum resins (for example, JP-A-2-301435, JP-A-2-302445, etc.) have been proposed. [0003] However, the method of blending a nucleating agent, the method of broadening the molecular weight distribution, and the method of increasing stereoregularity all generate gels and fish eyes when processed into a film. There is a problem that the appearance is remarkably inferior and the commercial value is impaired. In addition, the method of compounding petroleum resin generates smoke significantly during molding,
There are problems such as chill roll contamination. The present invention has been made in view of such circumstances, and has as its object to provide a polypropylene-based film and sheet having good moldability and appearance, and having excellent rigidity, water vapor barrier properties, and heat resistance. . [0005] The present inventors have conducted intensive studies and as a result, have found that the above object can be achieved by blending high density polyethylene with specific polypropylene. Based on this, the present invention has been completed. That is, (A) 100 parts by weight of polypropylene having the following physical properties (i) to (vi), and (i) a portion insoluble in xylene extraction at 25 ° C. 98.0.
% By weight or more (ii) Isotactic pentad fraction 96.5%
(Iii) Isotactic average chain length of 90 or more (iv) Total amount of isotactic average chain length of 300 or more of each fraction by column fractionation method 10
(B) A polypropylene film and sheet formed by molding a composition comprising 0.1 to 40 parts by weight of a high-density polyethylene (B). Hereinafter, the present invention will be described specifically. The (A) polypropylene according to the present invention comprises:
A homopolymer of propylene or a random or block copolymer of propylene with 20% by weight or less of another α-olefin such as ethylene, butene-1, hexene-1, 4-methylpentene-1, and octene-1; However, it is necessary to have the following physical properties. The polypropylene according to the present invention comprises (i) 2
The xylene extraction-insoluble portion (hereinafter referred to as “XI”) at 5 ° C. is 98.0% by weight or more, and preferably 98.5% by weight.
% By weight, more preferably 99.0% by weight or more. When XI is less than 98.0% by weight, rigidity and heat resistance are poor. In addition, XI is a ratio of the polymer which is obtained by dissolving polypropylene once in ortho-xylene at 135 ° C., cooling to 25 ° C., and precipitating in terms of% by weight. Further, (ii) an isotactic pentad fraction (hereinafter referred to as “IP”) of the polypropylene of the present invention.
Should be 96.5% or more, preferably 96.8% or more, and particularly preferably 97.0% or more. If the IP is less than 96.5%, the rigidity and heat resistance are inferior. In addition, IP is an isotactic fraction in a pentad unit in a polypropylene molecular chain measured using nuclear magnetic resonance ( ¹³ C-NMR) using isotope carbon. The measuring method is described in A. Zambelli; Macr
omolecules, 6 , 925 (1973), ibid.
8 , 687 (1975) and 13 , 267 (19).
80). The polypropylene of the present invention has a (iii) average isotactic chain length (hereinafter referred to as “N”) of 90.
Above, preferably 100 or more, particularly preferably 110 or more. If N is less than 90, rigidity and heat resistance are inferior. Note that N represents the average length of the isotactic portion of the methyl group in the polypropylene molecule. C. Randall; P
oligomer Sequese Distributi
on, AcademicPress, New York
1977, Chapter 2). [0010] Specifically, polypropylene is 1,2,4
Dissolve in a mixed solvent of trichlorobenzene / heavy benzene by heating to a temperature of 130 ° C. so that the polymer concentration becomes 10% by weight. This solution is placed in a 10 mmφ glass sample tube, and the ¹³ C-NMR spectrum is measured in the same manner as in IP. FIG. 1 shows an example of this spectrum diagram. In FIG. 1, a is a spectrum of a methyl group region in polypropylene, and b is an enlarged view of the spectrum.
The spectrum is measured using a pentad unit, that is, five adjacent methyl groups as one unit, and the absorption peak varies depending on the isotacticity of the methyl group (there are ten structural types such as mmmm and mmmr). FIG.
b shows the correspondence between the absorption peak and the isotacticity. On the other hand, Shan-Nong is a polymerization theory.
ZHU, etc .; Polymer Journal, vo
l. 15, No. 12, p859-868 (1983)
There is a two-site model described in. The theory is based on the assumption that there are two types of active species at the time of polymerization: a catalyst side and a polymer terminal, and the catalyst side is called catalyst-controlled polymerization, and the other is called terminal-controlled polymerization (for details, see Junji Furukawa). Essences of Polymers and Topics 2, "Polymer Synthesis", P73, published by Kagaku Dojin (1986)). According to the above literature, the two-site model is eventually: α: the probability that the D-form and the L-form are added to the polymerization terminal by the catalyst-controlled polymerization (enantiomorphic process), that is, the index σ of the degree of disorder in the isotactic chain. : Probability of formation of a meso-form which is the same as the polymerized terminal by terminal dominant polymerization (Bernoulli process) ω: 10 types of isotactic strengths with different isotacticity in pentad units are theoretically calculated as the ratio of α sites it can. Then, α, σ, and ω are determined by the least squares method so that the intensity measured by NMR and the theoretical intensity match, and each pentad unit is determined by the following equation. [Table 1] Here, β = α (1−α). C. The definition formula of the average chain length (N) described in Randall's document; N = the number of chains of the meso-form / the number of units of the meso-form, and can be actually obtained by the following formula. N = 1 + (A ₁ + A ₂ + A ₃ ) /0.5 (A ₄ + A ₅ +
A ₆ + A ₇ ) Further, the total amount of the polypropylene of the present invention having an isotactic average chain length (hereinafter referred to as “N _f ”) of 300 or more of each fraction by (iV) column fractionation method is 10 or more. It must be at least 30% by weight, particularly preferably at least 50% by weight. When the total amount of _Nf is 300 or more is 1
If it is less than 0% by weight, the effect of improving rigidity, surface hardness and heat resistance is poor. Here, the column fractionation method means that the above-mentioned XI subjected to xylene extraction is dissolved in para-xylene at a temperature of 130 ° C., celite is added, and a temperature of 3 ° C. is added at a rate of 10 ° C./hour.
Lower to 0 ° C. and attach to Celite. Next, a method is used in which a column is filled with slurry-like celite, the temperature is increased stepwise from 30 ° C. to 2.5 ° C. using para-xylene as a developing solution, and polypropylene is fractionated. For more information, see Masahiro Kakug
o et al; Macromolecules, vo
l. 21, p314-319 (1988). N _f prep polypropylene is determined using the measurement method of the N. [0016] in minutes (A) formed of the present invention, Ma Guneshiu <br/> arm compound, titanium compound, the solid catalyst and a halogen-containing compound and an electron donating compound essential components, or a solid catalyst And the general formula: TiXa.Yb (wherein X
Is a halogen atom of Cl, Br, I, Y is an electron donating compound, a is 3 or 4, and b is an integer of 3 or less.) And then washed with a halogen-containing compound. And propylene homopolymer, propylene-ethylene copolymer or propylene-ethylene block copolymer obtained by polymerization using an improved solid catalyst component obtained by washing with a hydrocarbon. The high-density polyethylene (B) in the present invention is an ethylene homopolymer having a density of 0.94 g / cm ³ or more or a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymerization ratio of the α-olefin is usually at most 20% by weight. Specific examples of the α-olefin include propylene, 1-butene, 3-methyl 1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, vinylcyclo Pentane, vinylcyclohexane and the like. These α-olefins may be used alone or in combination of two or more. The compounding amount of the component (B) is 0.1 to 40 parts by weight with respect to 100 parts by weight of the component (A), and 0.5 to 30 parts by weight.
Part by weight is preferred, and 1 to 20 parts by weight is particularly preferred.
When the amount of the component (B) is less than 0.1 part by weight, the improvement of the properties becomes insufficient. On the other hand, if it exceeds 40 parts by weight, the rigidity and heat resistance decrease, which is not preferable. As a compounding method, in addition to the method of mixing the above resins, a method of directly mixing in a reactor by a multi-stage polymerization method (for example, Japanese Patent Publication No. 46-38247,
JP-B-47-8207) may be used. The propylene-based film and sheet of the present invention are obtained by extruding the above composition, and are suitably used for food packaging materials such as ice cream and desserts, and medical packaging materials. Incidentally, the composition of the present invention includes additives commonly used by those skilled in the art, such as antioxidants, weathering stabilizers, antistatic agents, lubricants, antiblocking agents, antifogging agents,
Pigments, plasticizers, softeners and the like can be appropriately compounded within a range that does not impair the purpose of the present invention. The present invention will be described in more detail with reference to the following examples. The MFR conforms to JIS K7210,
The measurement was performed under the conditions of Table 1 and Condition 14. Tensile test is JIS K71
Extrusion direction (MD) and cross direction (TD)
, The yield strength, the breaking strength and the breaking elongation were measured at a tensile speed of 500 mm / min. Young's modulus is JIS
The MD was measured under the conditions of a tensile speed of 5 mm / min in accordance with K7127. Blocking strength is size 20cm ×
Two 8 cm films were stacked, sandwiched between stainless steel flat plates (size: 10 cm × 8 cm), and further kept in an oven at a temperature of 40 ° C. with a load of 100 g / cm ² for 24 hours. ℃, relative humidity 50%
Condition in a constant temperature room. Next, the peel strength of the film under the condition of a tensile speed of 50 mm / min was measured and evaluated. The friction coefficient was measured for MD under the condition of a friction speed of 150 mm / min in accordance with JIS K7125. The water vapor transmission rate is 37.8 ° C according to ASTM E96.
The measurement was performed under the conditions of ° C and 90% relative humidity. Surface gloss is J
It conformed to IS K7105. The tear strength is JIS K7
The MD was measured according to M.128. The production examples of the used polypropylene are shown below. (A) Preparation of solid catalyst 56.8 g (597 mmol) of anhydrous magnesium chloride
Was added to 100 g (174 mmol) of absolute ethanol, 500 ml of petrolatum oil (CP15N) manufactured by Idemitsu Kosan Co., Ltd., and 500 silicone oil (KF96) manufactured by Shin-Etsu Silicone Co., Ltd.
The mixture was completely dissolved at 120 ° C. under a nitrogen atmosphere in a mixed solution of 100 ml. This mixture was stirred for 3 minutes at 3,000 rpm at 120 ° C. using a TK homomixer manufactured by Tokushu Kika Kogyo Co., Ltd. It was then transferred into 2 liters of anhydrous heptane with cooling, maintaining the temperature below 0 ° C., while maintaining stirring. The obtained white solid was sufficiently washed with anhydrous heptane and dried under vacuum at room temperature. 30 g of the obtained white solid was mixed with anhydrous heptane 2
The suspension was suspended in 00 ml, and 500 ml (4.5 mol) of titanium tetrachloride was added dropwise over 1 hour while stirring at 0 ° C. Next, when heating was started and the temperature reached 40 ° C., 4.96 g (17.8 mmol) of diisobutyl phthalate was added, and the temperature was raised to 100 ° C. in about 1 hour. 2 at 100 ° C
After reacting for an hour, a solid portion was collected by hot filtration. 500 ml of titanium tetrachloride (4.5 mol) was added to the obtained solid portion.
1) was added thereto, and the mixture was reacted at 120 ° C. for 1 hour with stirring. Then, a solid portion was collected by hot filtration again, and washed 7 times with 1 liter of hexane at 60 ° C. and 3 times with 1 liter of hexane at room temperature. (B) TiCl ₄ [C ₆ H ₄ (COO ⁱ C
Preparation of ₄ H ₉ ) ₂ ] 27.8 g of diisobutyl phthalate was added to a solution of 1 g of hexane containing 19 g (100 mmol) of titanium tetrachloride.
(100 mmol) was added dropwise over about 30 minutes while maintaining 0 ° C. After the completion of the dropwise addition, the temperature was raised to 40 ° C., and the reaction was performed for 30 minutes. After the reaction was completed, a solid portion was collected and hexane 500 m
After washing 5 times with 1 l, the desired product was obtained. (C) Preparation of polymerization catalyst component 20 g of the solid catalyst obtained in the above (a) was added to 300 parts of toluene.
of the TiC obtained in (b) above at 25 ° C.
5.2 g of 11 ₄ [C ₆ H ₄ (COO ⁱ C ₄ H ₉ ) ₂ ]
mol) for 1 hour to be supported. After the loading was completed, the solid portion was collected by hot filtration, and resuspended in 300 ml of toluene and 10 ml (90 mmol) of titanium tetrachloride.
The mixture was washed by stirring at 0 ° C. for 1 hour, and a solid portion was collected by hot filtration.
And washed three times with 500 ml of hexane at room temperature. [0025] obtained under prepolymerization nitrogen atmosphere, in a content volume of 3-liter autoclave, n- heptane 500 ml, triethyl aluminum 6.0 g (53 mmol), dicyclopentyldimethoxysilane 0.39 g (17 mmol), and (c) above 10 g of the polymerization catalyst component thus obtained is added, and 0 to 5
The mixture was stirred for 5 minutes in a temperature range of ° C. Next, polymerization catalyst component 1
Propylene was fed into the autoclave so that 10 g of propylene per g was polymerized, and prepolymerized for 1 hour in a temperature range of 0 to 5 ° C. The obtained prepolymerized solid catalyst component was washed three times with 500 ml of n-heptane and used for the following main polymerization. Main Polymerization Under a nitrogen atmosphere, 2.0 g of the prepolymerized solid catalyst component prepared as described above and 11.4 g of triethylaluminum (10
0 mmol), dicyclopentyldimethoxysilane.
84 g (30 mmol) were added, and then propylene and 4000 mol ppm of hydrogen relative to propylene were charged, and the temperature was raised to 70 ° C., and polymerization was performed for 1 hour. afterwards,
Unreacted propylene was removed to terminate the polymerization. As a result, 6.6 kg of polypropylene (hereinafter referred to as “PP-1”) having an MFR of 34.2 g / 10 minutes was obtained. In the above operations (a) to (c),
Preliminary polymerization and main polymerization are performed by performing only the operation (a), and M obtained by performing the polymerization at a molar ratio of dicyclopentyldimethoxysilane and triethylaluminum of 0.3.
Propylene having an FR of 7.6 g / 10 minutes (hereinafter referred to as “PP
-2 "). Further, for comparison, AA type titanium trichloride manufactured by Tosoh Akzo Co., Ltd., and diethylaluminum chloride were used as catalyst components, and the hydrogen concentration at the time of polymerization was adjusted. PP-a "). With respect to the above polypropylene, XI, I
P, N and _Nf were measured. Table 2 shows the results.
In addition, the measurement conditions of IP are as follows. Measuring instrument JNM-GSX400 manufactured by JEOL Co., Ltd. Measurement mode: Proton decoupling method Pulse width: 8.0 μs Pulse repetition time: 3.0 s Integration frequency: 20,000 times Solvent: 1,2,4-trichlorobenzene /
Mixed solvent of heavy benzene (75/25 wt%) Internal circulation: hexamethyldisiloxane Sample concentration: 300 mg / 3.0 ml Solvent measurement temperature: 120 ° C. As the high-density polyethylene, polyethylene having a density of 0.958 g / cm ³ obtained using a chromium catalyst (hereinafter referred to as “PE-1”), and a density obtained using a titanium catalyst being 0% .959 g / cm ³ (hereinafter referred to as “PE-2”) and polyethylene having a density of 0.956 g / cm ³ (hereinafter “PE-2”).
Of -3 "), the density containing butene-1 as a copolymerizable component with polyethylene (hereinafter referred to as" PE-4 ") is 0.946 g / cm ^3. Examples 1 to 7 and Comparative Examples 1 to 5 Polypropylene and high-density polyethylene and di-t-butyl-p whose type and amount are shown in Table 3
-Cresol 0.05% by weight, pentaerythrityl-
Using 0.10% by weight of tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenylpropionate) and 0.10% by weight of calcium stearate using a super mixer (Model SMV20) manufactured by Kawada Seisakusho Co., Ltd. The mixture was pelletized using a twin screw extruder (Model AS30) manufactured by Nakatani Machinery Co., Ltd. Each of the obtained pellets was formed using a 40 mmφT die forming machine manufactured by Yoshii Iron Works Co., Ltd. at a die temperature of 230.
A film having a thickness of 60 μm was produced at a temperature of 10 ° C. and a take-up speed of 10 m / min. The physical properties of each of the obtained films were measured. Table 3 shows the results. [Table 3] [Table 3] The film and sheet of the present invention have good moldability and appearance, and are excellent in rigidity, water vapor barrier property and heat resistance, so that they are particularly suitable as packaging materials for food, medical and industrial parts. Useful.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a nuclear magnetic resonance spectrum in a methyl region of polypropylene, where a is a spectrum diagram and b is an enlarged view thereof.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-59-22913 (JP, A) JP-A-5-9226 (JP, A) JP-A-3-153709 (JP, A) JP-A 62-1987 86039 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 23/00-23/36 C08F 4/64-4/69

Claims (1)

(57) [Claims] [Claim 1] (A) 100 parts by weight of polypropylene having the following physical properties (i) to (vi) ; 94
g / cm ³ or more of a high-density polyethylene formed from a composition comprising 0.1 to 40 parts by weight of a polypropylene film or sheet , wherein (A) is a magnesium compound, a titanium compound,
Gen-containing compounds and electron-donating compounds as essential components
Or a solid catalyst having the general formula: T
iXa.Yb (where X is a halogen atom of Cl, Br, I)
Y represents an electron donating compound, a represents 3 or 4,
b represents an integer of 3 or less, respectively)
After treatment with the compound, wash with a halogen-containing compound and further carbonize.
Using an improved solid catalyst component obtained by washing with a hydrogen compound
Polypropylene-based film obtained by polymerization
And sheets . (i) Xylene extraction insoluble portion at 25 ° C. 98.0
% By weight or more (ii) Isotactic pentad fraction 96.5%
(Iii) Average isotactic chain length of 90 or more (iv) Total amount of fractions having an average isotactic chain length of 300 or more of each fraction by column fractionation 10
Weight% or more