JP2687503B2 - Polypropylene composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polypropylene composition having excellent transparency, low temperature impact resistance, heat sealability and the like.

[Conventional technology]

As a method of improving low temperature impact resistance and heat sealability of polypropylene, a method of adding an ethylene / propylene copolymer or an ethylene / 1-butene copolymer to polypropylene is well known. However, this composition does not have sufficient transparency improving effect. Further, when formed into a film, heat sealing at a low temperature is possible, but there is a problem that the heat sealing strength decreases.

As a method of improving the transparency of polypropylene, a method of adding a propylene / 1-butene copolymer to polypropylene has been proposed (Japanese Patent Publication No. 57-2437).
Four). However, this composition is still desired to be improved in terms of low temperature impact resistance.

[Problems to be solved by the invention]

An object of the present invention is to solve the above problems and provide a propylene composition having excellent transparency, low temperature impact resistance, low temperature heat sealability, heat seal strength and the like.

[Means for solving the problem]

The present invention relates to (A) a highly crystalline propylene polymer 40 to
95% by weight, and (B) a repeating unit (a) derived from propylene, a repeating unit (b) derived from ethylene, and a repeating unit (c) derived from an α-olefin having 4 to 20 carbon atoms. A propylene-based copolymer, wherein (i) the repeating unit (a) derived from propylene is 40 to 80 mol%, and the repeating unit (b) derived from ethylene.
Is 2 to 40 mol%, and the repeating unit (c) derived from the α-olefin is 0 to 40 mol%, and 20
<(B + c) <60 mol%, and (ii) the intrinsic viscosity [η] measured in decalin at 135 ° C is
Polypropylene composition characterized in that it is in the range of 0.1 to 7 dl / g, and (iii) is composed of 5 to 60% by weight of a propylene-based copolymer having a crystallinity of 40% or less measured by X-ray diffractometry. It is a thing.

In the polypropylene composition of the present invention, the highly crystalline propylene polymer as the component (A) is a homopolymer of propylene, or propylene and 10 mol% or less of an α-olefin having 2 or 4 to 20 carbon atoms. Is a highly crystalline copolymer of MFR (L) [ASTM D123 (L)]
0.1 to 200g / 10min, preferably 0.3 to 100g / 10mi
It is preferable that the intrinsic viscosity [η] measured in decalin at 135 ° C. is 1.0 to 5.0 dl / g, preferably 1.2 to 4.0 dl / g.

Examples of the above α-olefin include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-heptene, 1-heptene, 1
-Octene, 1-nonene, 1-decene, 1-dodecene,
Examples include 1-tetradecene, 1-octadecene,
These can be copolymerized singly or in combination of two or more.

In the polypropylene composition of the present invention, the propylene-based copolymer as the component (B) has a propylene component (repeating unit (a) derived from propylene) of 40 to 80 mol%, preferably 50 to 80 mol%, more preferably Is 50 to 70 mol%, the ethylene component (the repeating unit (b) derived from ethylene) is 2 to 40 mol%, preferably 5 to 40 mol%, more preferably 10 to 35 mol%, and the number of carbon atoms is 4 0 to 40 mol%, preferably 10 to 35 mol%, more preferably 15 to 30 mol of α-olefin component (repeating unit (c) derived from α-olefin having 4 to 20 carbon atoms). % Range.

1 as an α-olefin having 4 to 20 carbon atoms
-Butene, 1-pentene, 1-hexene, 4-methyl-
1-Pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-octadecene, etc.
Those having 18 or less are preferable, and those having 4 to 10 carbon atoms are particularly preferable.

When the propylene component in the component (B) is more than 80 mol%, the melting point is high and the impact resistance and heat sealability are insufficient. When the propylene component is less than 40 mol%, the melting point,
The crystallinity is low and the blocking property is high. Also,
If the ethylene component in the component (B) exceeds 40 mol%, the polymer becomes non-uniform and the transparency becomes insufficient. When the ethylene content is less than 2 mol%, the melting point and crystallinity are high, and the impact resistance is insufficient. Further, when the content of the α-olefin component in the component (B) is more than 40 mol%, the melting point and the crystallinity are low and the blocking property becomes large. Here, the composition of the copolymer component is determined from the infrared absorption spectrum of the press film.

Component (B) of propylene-based copolymer in decalin 135
The intrinsic viscosity [η] measured in ° C is in the range of 0.1 to 7 dl / g, preferably 0.2 to 5 dl / g. This characteristic value is a scale showing the molecular weight of the propylene-based copolymer as the component (B), and by combining with other characteristic values, it serves to provide the propylene-based copolymer having the above-mentioned excellent properties.

The propylene copolymer as the component (B) has a crystallinity of 40% or less, preferably 30% or less, as measured by an X-ray diffraction method. This characteristic value is a measure showing that the propylene-based copolymer as the component (B) is excellent in impact resistance, and by combining with other characteristic values, it is possible to provide the propylene-based copolymer having the above-mentioned excellent properties. It is useful. The crystallinity is determined by X-ray diffraction measurement of a press sheet having a thickness of 1.5 mm 20 hours after the molding.

The polypropylene composition of the present invention contains the highly crystalline propylene polymer (A) in an amount of 40 to 95% by weight, preferably
50 to 90% by weight, and 5 to 60% by weight, preferably 10 to 50% by weight of the above-mentioned propylene-based copolymer (B) are blended. When the compounding ratio of the low crystalline propylene-based copolymer (B) is less than 5% by weight, the low temperature impact resistance and the heat sealability are not sufficiently improved, and when it exceeds 60% by weight, the heat resistance is deteriorated.

The polypropylene composition of the present invention contains the above-mentioned components (A) and (B) as essential components. However, other than these essential components, other resins and heat-resistant components may be used within the range not deviating from the object of the present invention. Stabilizers, weathering stabilizers, antistatic agents, slip agents, anti-blocking agents, anti-fog agents, lubricants, dyes, pigments, fillers, natural oils, synthetic oils, compounding agents such as waxes can be compounded. The mixing ratio is an appropriate amount.

Next, a method for producing the propylene-based copolymer as the component (B) will be described.

As described in JP-A-62-241910, a method for producing a propylene-based copolymer as the component (B) has a high stereoregularity containing magnesium, titanium, halogen and an electron donor as essential components. It can be produced by copolymerizing propylene, ethylene and an α-olefin having 4 to 20 carbon atoms in the presence of a catalyst formed from a titanium catalyst component, an organoaluminum compound catalyst component, and an electron donating catalyst component. it can.

The above-mentioned highly active, highly stereoregular solid titanium catalyst component used for the production of the component (B) contains magnesium, titanium, halogen and an electron donor as essential components, and the magnesium / titanium (atomic ratio) is Greater than 1, preferably 3 to 50, particularly preferably 6 to 30, halogen / titanium (atomic ratio) is preferably 4 to 100, particularly preferably 6 to 40, electron donor / titanium (molar ratio) is preferred. It is preferably in the range of 0.1 to 10, particularly preferably 0.2 to 6. Its specific surface area is preferably 3 m ² / g or more, more preferably 40 m ² / g
Above all, more preferably 100 to 800 m ² / g. The solid titanium catalyst component has an average particle size of, for example, 1 to 20.
0 μm, preferably 3 to 100 μm, particularly preferably 6 to 50 μm, and the geometric standard deviation of particle size distribution is, for example, less than 2.1, preferably 1.9 or less, more preferably
It is preferably 1.7 or less.

A titanium catalyst component that satisfies all of the above conditions is, for example, a method of forming a magnesium compound having an average particle size and particle size distribution, more preferably a shape in the above range, and then performing catalyst preparation, or It can be obtained by a method of bringing a liquid magnesium compound and a liquid titanium compound into contact with each other to form a solid catalyst having the above-mentioned particle properties. Such a method is disclosed in, for example, JP-A Nos. 55-135102 and 55-135103.
No. 56-811, No. 56-67311, No. 58-83006 and the like.

As the magnesium compound used for the preparation of the titanium catalyst component, magnesium oxide, magnesium hydroxide, hydrotalcite, magnesium carboxylate, alkoxy magnesium, allyloxy magnesium, alkoxy magnesium halide, allyloxy magnesium halide, magnesium dihalide, Examples thereof include organomagnesium compounds, reaction products of organomagnesium compounds with electron donors, halosilanes, alkoxysilanes, silanols, aluminum compounds and the like. The organoaluminum compound that may be used to prepare the titanium catalyst component can be selected from the organoaluminum compounds described below. Furthermore, examples of the halogen-containing silicon compound that may be used for preparing the titanium catalyst component include silicon tetrahalides, silicon alkoxy halides, silicon alkyl halides, and halopolysiloxanes.

Examples of titanium compounds used in the preparation of the titanium catalyst component include titanium tetrahalides, alkoxy titanium halides, allyloxy titanium halides, alkoxy titanium, allyloxy titanium, and the like, particularly titanium tetrahalide, especially titanium tetrachloride. Is preferred.

Electron donors that can be used to prepare the titanium catalyst component include alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic or inorganic acids, ethers, acid amides, alkoxysilanes of acid anhydrides. Examples thereof include oxygen-containing electron donors, nitrogen-containing electron donors such as ammonia, amines, nitriles and isocyanates.

The preferred organoaluminum compound catalyst component used in the production of the component (B) is an organoaluminum compound, and a compound having at least one aluminum-carbon bond in the molecule can be used.
(I) General formula R ¹ _m Al (OR ² ) _n H _p X _q (wherein R ¹ and R ² are hydrocarbon groups usually containing 1 to 15, preferably 1 to 4 carbon atoms, and are the same as each other. X may be halogen, m may be 0 <m ≦ 3, n may be 0 ≦ n <3, and p may be 0 ≦.
p <3, q is a number 0 ≦ q <3, and m + n +
p + q = a 3) an organoaluminum compound represented by, (ii) the general formula M ¹ AlR ¹ ₄ (M ¹ is here Li, Na, K, and the Periodic Table R ¹ is represented by the same) and the Examples thereof include complex alkyl products of a metal belonging to Group 1 and aluminum.

Examples of the organoaluminum compound belonging to the above (i) include a general formula R ¹ _m Al (OR ² ) _3-m (where R ¹ and R ² are the same as above. M is preferably a number of 1.5 ≦ m ≦ 3) there), the general formula R ¹ _m AlX _3-m (wherein R ¹ is as .X said halogen, m is preferably 0 <m <3), the general formula R ¹ _m AlH
_3-m (where R ¹ is the same as above. M is preferably 2 ≦ m <
3), the general formula R ¹ _m Al (OR ² ) _n X _q (where R ¹ and R
² is the same as above. X is halogen, m is 0 <m ≦ 3, 0 ≦
n <3, 0 ≦ q <3, and m + n + q = 3).

As the compound belonging to the above (ii), LiAl (C
_{2 H 5) 4, LiAl (} C 7 H 15) 4 etc. can be exemplified. Among these, it is particularly preferable to use trialkylaluminum, or a mixture of trialkylaluminum and alkylaluminum halide or aluminum halide.

Examples of the electron donor catalyst component used for producing the component (B) include amines, amides, ethers, ketones, nitriles, phosphines, stibines, arsines, phosphoramides and esters. , Thioethers, thioesters, acid anhydrides, acid halides, aldehydes, alcoholates, alkoxy (allyloxy) silanes, organic acids and amides of metals belonging to Groups 1 to 4 of the periodic table. And salt.

The propylene-based copolymer as the component (B) can be produced in the presence of a catalyst formed from the titanium catalyst component, the organoaluminum compound catalyst component of the above, and the electron donor catalyst component of the above, in an inert hydrocarbon solvent, Or propylene, ethylene and C4-20 without solvent
The above-mentioned α-olefin is copolymerized.
In this case, it is particularly preferable to employ a method in which the copolymerization reaction is carried out under the condition that the copolymer produced in an inert hydrocarbon solvent is dissolved.

When carrying out a copolymerization reaction, with respect to 1 g of the titanium catalyst component, 100 to 100,000 g, preferably 150 to 20,0
00 g, more preferably 200 to 10,000 g propylene,
It is desirable to copolymerize ethylene and an α-olefin having 4 to 20 carbon atoms.

When an inert solvent is used in the copolymerization reaction, 0.001 to 500 mmol, particularly preferably 0.
It is preferably 005 to 200 mmol, and the catalyst component of the organoaluminum compound has an Al / Ti (atomic ratio) of 0.1.
It is preferable to use it in a ratio such that it is from 1 to 1000, particularly preferably from 0.5 to 500. Further, the electron donor catalyst component may be supported on the titanium catalyst component of
It may be used in addition to the organoaluminum compound catalyst component of, or may be added to the polymerization system in a free state. In any case, the electron donor catalyst component is titanium atom 1
It may be present in an amount of 0.1 to 200 mol, particularly preferably 0.2 to 50 mol per mol.

As the inert hydrocarbon solvent used in the copolymerization reaction, propane, butane, n-pentane, isopentane,
Aliphatic hydrocarbons such as n-hexane, isohexane, n-heptane, n-octane, isooctane, n-decane, n-dodecane and kerosene, alicyclic carbonization such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane Examples thereof include hydrogen, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as methylene chloride, ethyl chloride, ethylene chloride and chlorobenzene. Among them, aliphatic hydrocarbons, especially carbon number 4 to 10 aliphatic hydrocarbons are preferred.

The copolymerization temperature can be appropriately selected, preferably about 20 to about 200 ° C., more preferably about 50 to about 180 ° C., and the pressure can also be appropriately selected, from atmospheric pressure to about 100 kg / cm ² , preferably from atmospheric pressure to about 100 kg / cm ² . It is preferable to carry out under a pressurized condition of about 50 kg / cm ² .

The molecular weight can be adjusted to some extent by changing the polymerization conditions such as the polymerization temperature and the proportion of the catalyst component used. However, it is most effective to add hydrogen to the polymerization system.

Since the polypropylene composition of the present invention has excellent transparency and low temperature impact resistance, it is suitable for use in molded articles such as bottles and other containers, and sheets. It also has excellent heat-sealing properties and can be heat-sealed at low temperatures.
Since it has excellent heat-sealing strength, it can be widely used as a molded product such as a packaging film in addition to the above-mentioned applications.

〔The invention's effect〕

According to the present invention, since a specific propylene-based copolymer is blended with a highly crystalline propylene polymer, a polypropylene composition excellent in transparency, low temperature impact resistance, low temperature heat sealability, heat seal strength and the like can be obtained. .

〔Example〕

 Hereinafter, examples of the present invention will be described.

Reference Example 1 Production of Propylene Copolymer (B) <Preparation of Titanium Catalyst Component> Anhydrous magnesium chloride 4.76 g (50 mmol), decane 25 ml
And 23.4 ml of 2-ethylhexyl alcohol (150mmo
l) After heating for 2 hours at 130 ° C to make a homogeneous solution,
1.11 g (7.5 mmol) of phthalic anhydride was added to this solution,
Stir and mix at 130 ° C. for another hour to dissolve phthalic anhydride in the homogeneous solution. The homogeneous solution thus obtained is cooled to room temperature and then poured into 200 ml (1.8 mol) of titanium tetrachloride kept at -20 ° C dropwise over 1 hour. After the injection was completed, the temperature of this mixed solution was raised to 110 ° C. over 4 hours, and when it reached 110 ° C., 2.68 ml (12.5 mmol) of diisobutyl phthalate was added, and the mixture was stirred for 2 hours.
Hold the temperature at 110 ° C for hours. After the completion of the reaction for 2 hours, a solid part was collected by hot filtration, and the solid part was resuspended in 200 ml of TiCl ₄ and then again heated at 110 ° C. for 2 hours.
After the completion of the reaction, the solid part is again collected by hot filtration, and thoroughly washed with decane and hexane at 110 ° C. until no free titanium compound is detected in the washing liquid.

The composition of the titanium catalyst component synthesized by the above manufacturing method is titanium 3.1% by weight, chlorine 56.0% by weight, magnesium 17.
0% by weight and 20.9% by weight of diisobutyl phthalate.

<Polymerization> Using a continuous polymerization reactor with an internal volume of 200, dehydrated and purified hexane was 100 / hr, ethylene was 0.5 kg / hr, propylene was 5.5 kg / hr, and 1-butene was 6.0 kg / hr. Also, hydrogen was supplied so that the gas phase concentration in the polymerization reactor would be 5 mol%, while the titanium catalyst component was converted to titanium atoms to 1.2 mmo.
l / hr, triisobutylaluminum 60 mmol / hr and diphenyldimethoxysilane 7.2 mmol / hr were supplied, and copolymerization was carried out under the conditions of a polymerization temperature of 70 ° C., a polymerization pressure of 2 kg / cm ² and a residence time of 1 hour. .

The physical properties of the obtained propylene / ethylene / 1-butene copolymer (hereinafter referred to as PEB-1) are as follows:
%, Ethylene content 14mol%, 1-butene content 22mol
%, Intrinsic viscosity [η] = 1.5 dl / g, crystallinity = 16%, melting point (Tm) = 64 ° C.

Example 1 30% by weight of PEB-1 described above and a highly crystalline propylene / ethylene random copolymer (MFR (L): 20 g / 10 min, ethylene content: 2.7 mol%, intrinsic viscosity [η]: 1.6 dl / g, Below PP-
70% by weight is mixed with a Henschel mixer, and then melt-kneaded in a single-screw extruder (set temperature: 230 ° C.) to obtain a composition I.
I got

Then, using the composition I, a test piece was molded by an injection molding machine. For this test piece, the initial flexural modulus,
IZOD impact strength and haze were measured by the following methods. The results are shown in Table 1.

(1) Initial flexural modulus (kgf / cm ² ): ASTM D790 (2) IZOD impact strength (kgcm / cm): ASTM D256 (with notch) (3) Haze (%): ASTM D1003 (2mm thickness) Comparative Example 1 Instead of PEB-1 used in Example 1, a low crystalline ethylene / 1-butene random copolymer produced according to Reference Example 1 (MFR (E): 3.6 g / 10 min, density: 0.886 g / cm ³ , melting point: 70 ° C., 1-butene content: 11 mol%, hereinafter referred to as EB-1) were used in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 Instead of PEB-1 used in Example 1, a low crystalline propylene / 1-butene random copolymer produced according to Reference Example 1 (MFR (L): 7.0 g / 10 min, density: 0.885 g / cm ³ ,
Melting point: 110 ° C., 1-butene content: 28 mol%, hereinafter referred to as PB-1) were used in the same manner as in Example 1. The results are shown in Table 1.

Example 2 20% by weight of PEB-1 used in Example 1 and a highly crystalline propylene / ethylene random copolymer (MFR (L): 6.5 g / 10 m)
in, ethylene content: 4.7 mol%, hereinafter referred to as PP-2) 80
% By weight with a Henschel mixer, and then the mixed composition is cast film molding machine with a width of 250 mm and a thickness of 50 μm.
A test film of was molded. The resin temperature during molding is
230 ℃, chill roll temperature is 20 ℃, screw rotation speed is 80 rpm
I went in.

The test film was measured for impact strength at 0 ° C., haze and heat seal strength by the following methods. The results are shown in Table 2.

(1) Impact strength (kg ・ cm / cm): ASTM D3420 (2) Haze (%): ASTM D1003 (3) Heat seal strength (g / 15mm width): Heat seal pressure; 2kg / cm ² heat seal time; 1 sec Tensile speed: 300 mm / min Comparative Example 3 The same procedure as in Example 2 was carried out except that EB-1 used in Comparative Example 1 was used instead of PEB-1 used in Example 2. The results are shown in Table 2.

Comparative Example 4 The procedure of Example 2 was repeated except that PB-1 used in Comparative Example 2 was used instead of PEB-1 used in Example 2. The results are shown in Table 2.

Claims (1)

(57) [Claims] 1. A highly crystalline propylene polymer 40 to 40
95% by weight, and (B) a repeating unit (a) derived from propylene, a repeating unit (b) derived from ethylene, and a repeating unit (c) derived from an α-olefin having 4 to 20 carbon atoms. A propylene-based copolymer, wherein (i) the repeating unit (a) derived from propylene is 40 to 80 mol%, and the repeating unit (b) derived from ethylene.
Is 2 to 40 mol%, and the repeating unit (c) derived from the α-olefin is 0 to 40 mol%, and 20
<(B + c) <60 mol%, and (ii) the intrinsic viscosity [η] measured in decalin at 135 ° C is
Polypropylene composition characterized in that it is in the range of 0.1 to 7 dl / g, and (iii) is composed of 5 to 60% by weight of a propylene-based copolymer having a crystallinity of 40% or less measured by X-ray diffractometry. Stuff.