JPS6347741B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyolefin compositions. More specifically, the present invention relates to a polyolefin composition which is a mixture of a high molecular weight polyolefin and a low molecular weight polyolefin and is excellent in rigidity, environmental cracking resistance, moldability, that is, flowability and balance effect. Generally, fluidity and balance effects are important in blow molding and extrusion molding of polyolefins. Generally, the higher the flow rate ratio (defined later), the better the fluidity and the higher the molding speed. However, in such a case, the balance effect generally becomes large, which has the drawback that the parison becomes thicker and thicker during blow molding, and edge tear occurs during extrusion sheet molding. Therefore, the present inventors investigated a polyolefin composition with excellent fluidity and low balance effect, and as a result, they identified the density, molecular weight, molecular weight ratio, blending ratio, etc. of the polyethylene to be mixed, and identified a catalyst for producing polyethylene. The inventors have discovered that a polyolefin composition with high fluidity and low ballast effect can be obtained by doing so, and the present invention has been achieved. The gist of the present invention is to use 30 to 60 parts by weight of polyolefin A having a density of 0.915 to 0.955 and a viscosity average molecular weight of 150,000 to 500,000;
Polyolefin A and polyolefin B are a reaction product of an oxygen-containing organic compound of magnesium and a titanium halide compound, or a reaction product of an oxygen-containing organic compound of magnesium and an oxygen-containing titanium compound. An ethylene homopolymer or a copolymer of ethylene and other α-olefins produced using a reaction product of an organic compound and an aluminum halide compound and a catalyst consisting of an organoaluminum compound is used, and (polyolefin A (viscosity average molecular weight of polyolefin B)/(viscosity average molecular weight of polyolefin B)
Melt index is 0.05 to 10 to 50
The polyolefin composition has an outflow ratio of 0.5 and 50 or more. To explain the present invention in detail, polyolefin A and polyolefin B mixed in the present invention are ethylene homopolymer or ethylene and other α
-It is a copolymer with olefin. Other α-olefins in the copolymer include propylene and butene-1, and those whose content is 5% by weight or less are usually used. Its physical properties are selected as follows. As polyolefin A, the density is 0.915~
0.955 and a viscosity average molecular weight of 150,000 to 500,000 is used. Particularly preferably 98 mol% of ethylene units
~99.9 mol% and 2 mol% of other α-olefin units
~0.1 mol% copolymer is used. Other α-olefins that are copolymer components include compounds represented by the general formula R-CH=CH ₂ (wherein R represents an alkyl group having 1 to 12 carbon atoms), such as propylene, butene-1, Examples include hexene-1,4-methylpentene-1. Ethylene content is 99.9
If the content of other α-olefins exceeds mol%
If it is less than 0.1 mol%, no improvement in moldability (fluidity) is observed, and environmental cracking resistance decreases, which is not preferable. If the ethylene content is less than 98 mol % and the other α-olefin content exceeds 2 mol %, the stiffness of the composition will decrease significantly, which is not preferable. The density is the value measured according to ASTM D1505, and the viscosity average molecular weight is the intrinsic viscosity measured in a tetralin solution at 130°C, [η] = 4.60 × 10 ^-4 × M ^0.725
([η] is the intrinsic viscosity and M is the viscosity average molecular weight). However, if the density is lower than this range, the stiffness of the composition will be too low, and if the viscosity average molecular weight is less than 150,000, the impact strength, tear strength, and environmental cracking resistance of the polyolefin composition will be low; If it exceeds this, the balance effect of the blend will increase, which is not preferable. The weight average molecular weight/number average molecular weight (measured by gel permeation chromatography) is preferably 2 to 8, and the melt index (according to the measurement method described later) is preferably 0.1 to 0.002. On the other hand, polyolefin B has a density of 0.940.
to 0.977, preferably 0.960 to 0.977, and a viscosity average molecular weight of 10,000 to 40,000, preferably 10,000 to 30,000. If the density is lower than this range, the rigidity of the composition will be insufficient, and if the viscosity average molecular weight is less than 10,000, the impact strength of the polyolefin composition will decrease,
If it exceeds 40,000, the moldability deteriorates, which is not preferable. The weight average molecular weight/number average molecular weight is 2~
5. The melt index is preferably 24-1300. If the weight average molecular weight/number average molecular weight exceeds this range, the balancing effect will become undesirable. Furthermore, in the present invention, (viscosity average molecular weight of polyolefin A)/(polyolefin B
(viscosity average molecular weight) of 10 to 50, preferably 15 to 45
shall be. If this ratio is less than 10, the fluidity of the polyolefin composition decreases, and if it exceeds 50, the impact strength of the polyolefin composition decreases, and the balancing effect increases, which is not preferable. Therefore, polyolefin A and polyolefin B used in the present invention are the reaction products (a) of an oxygen-containing organic compound of magnesium and a titanium halide compound, or a reaction product (a) of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and aluminum. It is produced using a catalyst consisting of a reaction product (b) with a halogen compound and an organoaluminum compound. By using polyolefins produced using these catalysts, polyolefin compositions with particularly excellent moldability can be obtained, and other catalysts such as titanium trichloride-alkyl aluminum, titanium tetrachloride-trialkoxyvanadyl- This is advantageous over the use of polyolefins made with alkyl aluminum systems, chromium oxide/silica-diethyl aluminum monoethoxide systems. To explain the catalyst used, the oxygen-containing organic compound of magnesium used in preparing the reaction product (a) is Mg(OR ¹ ) _n X ¹ _2-n
(In the formula, R ¹ represents an alkyl group, aryl group or cycloalkyl group, X ¹ represents a halogen atom,
m represents 1 or 2. ) Examples include magnesium diethoxide, magnesium dimethoxide, magnesium diphenoxide, magnesium monoethoxy chloride, magnesium monophenoxy chloride, magnesium monoethoxy bromide, magnesium monoethoxy iodide, and the like. The titanium halogen compound has the general formula TiX ² _o (OR ² ) _4-o (wherein, X ² represents a halogen atom, R ² represents an alkyl group, an aryl group, or a cycloalkyl group, and n represents 1 to 4 ), such as titanium tetrachloride,
Examples include titanium tetrahalides such as titanium tetrabromide and titanium tetraiodide, titanium monoethoxytrichloride, titanium monomethoxytribromo, and titanium diethoxydichloride. Among these, titanium tetrahalide is preferred. The reaction between the oxygen-containing organic compound of magnesium and the titanium halide compound is carried out at 50°C or higher in the presence or absence of an inert hydrocarbon solvent.
It is carried out by contact at a temperature of 200°C.
The reaction product is obtained as a precipitate, and unreacted substances are washed away with an inert hydrocarbon solvent. There is no particular limit to the atomic ratio of titanium to magnesium in the reaction ratio between the two, but if it is too large, titanium will be wasted, and if it is too small, the polymerization activity will decrease. So usually
It is preferable that the molar ratio of Ti/Mg is 0.1 to 100. Next, the oxygen-containing organic compound of magnesium used in preparing the reaction product (b) is:
Magnesium compounds of the general formula shown above may likewise be mentioned. ^The oxygen-containing organic compound ^of titanium has the general formula _Ti ^{(OR 3 )} _k (representing a number from 1 to 4), for example, tetraethoxytitanium,
Examples include tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetraphenoxy titanium, triethoxy monochloro titanium, tri-n-butoxy monochloro titanium, diethoxy dichloro titanium, tri-n-butoxy monobrom titanium, and the like. Among these, compounds with k of 3 or 4 are preferred. ^{The aluminum} _halogen compound has ^the general formula AlR ⁴ _p ), such as ethylaluminum dichloride, normal propylaluminum dichloride, ethylaluminum sesquichloride, diethylaluminum monochloride, and the like. Among these, compounds in which X ⁴ is chlorine and p is 1 are preferred. The reaction between the oxygen-containing organic compound of magnesium, the oxygen-containing organic compound of titanium, and the aluminum halide is carried out by first mixing the oxygen-containing organic compound of magnesium and the oxygen-containing organic compound of titanium and heating the mixture to 100°C to 160°C. Prepare a homogeneous liquid. If it is difficult to produce a uniform liquid, it is preferable to include alcohol.
Next, an inert hydrocarbon solvent is added to obtain an inert hydrocarbon solution. When alcohol is used, it is preferable to remove the alcohol by distillation or the like. When an aluminum halogen compound is added to the inert hydrocarbon solution obtained as above and reacted at room temperature to 100℃, the reaction product is obtained as a precipitate, and unreacted substances are washed with an inert hydrocarbon solvent. removed. The quantitative ratio of each component is the atomic ratio of titanium to magnesium (Ti/Mg),
The ratio (X/Mg+Ti) of the sum of gram equivalents of all halogens to the sum of gram equivalents of magnesium and titanium is preferably 1.0 to 10. Note that the total halogen herein refers to the halogen contained in the oxygen-containing organic compound of magnesium, the oxygen-containing organic compound of titanium, and the aluminum halogen compound. On the other hand, ^the organoaluminum compound used as a cocatalyst has the general formula AlR ⁵ _q X ⁵ _3-q (wherein R ⁵ represents an alkyl group, aryl group, or cycloalkyl group, represents a number from 1 to 3), such as triethylaluminum, tri-n-propyl aluminum, tri-n-butyl aluminum, triisobutyl aluminum, diethylaluminum monochloride, di-n-propyl aluminum monochloride, and the like. Ethylene homopolymers or copolymers of ethylene and other α-olefins can be produced by combining ethylene or ethylene with the reaction product (a) or (b) obtained as described above and an organoaluminum compound. other α
-Produced by polymerizing a mixture with olefins. Polymerization may be carried out by a conventional method, at a temperature of room temperature to 200°C in the presence or absence of an inert hydrocarbon solvent,
It is carried out at a pressure of normal pressure to 100 atmospheres in the presence of hydrogen or the like. The ratio of the reaction product (a) or (b) to the organoaluminum compound is usually selected from the range of 0.05 to 100, preferably 0.07 to 50 in terms of Al/Ti atomic ratio. However, polyolefin A and polyolefin B
The mixing ratio of polyolefin A is 30 to 60 parts by weight, preferably 35 to 55 parts by weight, and polyolefin B is 70 to 40 parts by weight, preferably 65 to 45 parts by weight, per 100 parts by weight of the composition. do. If the polyolefin A is less than 30 parts by weight and the polyolefin B is more than 70 parts by weight, the melt elasticity of the polyolefin composition will increase and the so-called balance effect will increase, making it undesirable for general blowing purposes. If the amount of polyolefin A is more than 60 parts by weight and the amount of polyolefin B is less than 40 parts by weight, the fluidity of the polyolefin composition decreases, which is not preferable. The mixing method is not particularly limited and any known method may be used. For example, a solution mixing method in which polyolefins A and B are dissolved individually or together in a solvent, mixed, and then precipitated, CIM (Continuos Intensive Mixer),
Examples include a continuous melt-kneading method using an FCM (Farrel Continuos Mixer) or a single-screw extruder, and a batch-type melt-kneading method using a Banbury mixer. Among these, mixing using a Banbury mixer is preferable in terms of uniformity of the blended polymer. Note that during mixing, stabilizers, colorants, fillers, and other additives may also be mixed. Therefore, in the present invention, polyolefin A and polyolefin B are mixed and the melt index is 0.05.
The polyolefin composition has an outflow ratio of 50 or more with a ratio of ~0.5. Here, the melt index (abbreviated as MI) is based on ASTM D-1238, 190℃, 2.16Kg
The value measured under load is in g/10 min, and the flow rate ratio is calculated using a melt indexing device based on ASTM D-1238 at shear stress values of 10 ⁶ dyne/cm ² and 10 ⁵ dyne/cm ^2. Outflow ratio (MI10 ⁶ /
MI10 ⁵ , abbreviated as FR). If the melt index exceeds 0.5, mechanical properties such as tensile strength and tear strength will decrease, and if FR is less than 50, moldability, that is, fluidity will decrease, which is not preferable. The composition of the present invention obtained as described above has excellent fluidity, has a small balancing effect, has high rigidity, and has excellent environmental cracking resistance. The resin is suitable for extrusion molding or blow molding. That is, the composition of the present invention has a large extrusion amount per rotational speed in an extruder, and in addition to high extrusion productivity, it also has a low balance effect, so when it is made into a general blow container by blow molding. It has the advantage that a thin product can be obtained, and in the case of extrusion sheet molding, no edge tear occurs. It is also particularly advantageous to have excellent environmental cracking resistance. Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In the following examples, the amount of extrusion molding as a measure of moldability was determined using a Brabender 21D single-screw extruder (diameter 19.1 mmφ, L/D = 21, compression ratio = 3).
Measure the extrusion amount using a full-flight screw (circular die with a diameter of 20 mmφ and a clearance of 0.5 mm) at a die temperature of 200°C and a rotation speed of 150 revolutions/min. The amount of extrusion molded per rotational speed was determined by dividing by . Environmental cracking resistance was measured by the bell telephone method described in ASTM D-1693. The time required for 5 out of 10 test pieces to break was expressed. Tensile impact strength is ASTM D-
Obtained using 1822L. Viscosity average molecular weight, MI, FR
was determined according to the method described above. The density (abbreviated as ρ) is
Measured according to ASTM D-1505. The ballast effect was measured using a Shimadzu flow tester with a diameter of 1 mm, L/D = 2, and an inflow angle to the nozzle.
Measurements were made at 190°C using a 30° nozzle. The value of the ballast effect (abbreviated as α) is expressed as the ratio of (cross-sectional area of the extruded object)/(cross-sectional area of the nozzle) at 190°C, and in particular, the value when the shear rate = 1000 sec ^-1 (abbreviated as α ₁₀₀₀ ) is It was also expressed. The smaller α ₁₀₀₀ , the smaller the balance effect. The weight average molecular weight/number average molecular weight (abbreviated as Mw/Mn) was determined by measuring the molecular weight distribution by gel permeation chromatography under the following conditions and calculating from the distribution. In addition, the molecular weight distribution was obtained by obtaining a calibration curve from the chromatographic count number to the viscosity average molecular weight of the fractionated polyethylene, and then using this calibration curve to obtain the distribution. Model: Waters Model 200 Chromatography Solvent: O-dichlorobenzene Column: Polystyrene gel GMS (Toyo Soda Co., Ltd., trademark) 4 main flow rate: 1 c.c./min Polyethylene concentration: 0.25 parts by weight % Charge amount: 2 c.c. Reference example Using any of the following catalyst systems A, B, C, D, or E, the partial pressure of ethylene is 5.0 Kg/cm ² , the partial pressure of hydrogen shown in Table 1, Polyethylene was polymerized at a temperature of 70 to 90°C to produce polyethylene having the physical properties shown in Table 1. (a) 10.0 g of Mg (OC ₂ H ₅ ) ₂ and 70 ml of TiCl ₄ at 130°C.
The reaction was allowed to proceed for 2 hours. After cooling, it was washed with n-hexane and the supernatant liquid was removed. After repeating this several times, a catalyst consisting of the obtained solid and triisobutylaluminum is obtained. (b) Mg (OC ₂ H ₅ ) ₂ 100 mmol and Ti
(OC ₄ H ₉ ) ₄ and 100 mmol were mixed at 150° C. for 3 hours to homogenize. After cooling, 500 ml of n-hexane was added, and while stirring thoroughly, 300 mmol of AlC ₂ H ₅ Cl ₂ was gradually added dropwise. A solid precipitate is formed from the beginning of dropping, but after dropping this slurry, 65
The mixture was aged for 2 hours at ℃ and further washed with n-hexane to remove the supernatant. A catalyst consisting of triisobutylaluminum and a solid obtained by repeated washing with n-hexane. (c) Commercially available titanium trichloride (manufactured by Toyo Stauffer Co., Ltd.)
A catalyst consisting of AA titanium trichloride) and triisobutylaluminum. (d) An equimolar mixture of titanium tetrachloride and tri-n-butoxyvanadyl VO(OC ₄ H ₉ ) ₃ was treated in cyclohexane at 60°C, and then ethylaluminum sesquichloride was added at 25°C to reduce the resulting solid. Triisobutylaluminum. (e) A catalyst in which chromium oxide is supported on silica and activated with dry air at 800°C for 1 hour, and diethylaluminum monoethoxide. Examples 1 to 8 and Comparative Examples 1 to 7 Using the polyolefin produced in the reference example, high molecular weight components (components A1 to 14) and low molecular weight components (components 1 to 8) were mixed in Banbury in the proportions shown in Table 2. Mixing using a mixer or using a solution was performed. Table 2 shows the results of measuring the physical properties of the obtained polyolefin composition. The details of the mixing method are as follows. Mixing using a Banbury mixer: Polyolefin powders A and B are mixed at a predetermined weight ratio, and the total amount of polyolefin powders A and B is 260 g. This mixed powder is placed in a Banbury mixer, and the mixer is sufficiently purged with nitrogen. Knead for 3 minutes at a rotation speed of 200 rpm and a shear rate of 420 sec ^-1 . Mixing by solution: Polyolefins A and B were charged in a predetermined weight ratio in a total amount of 300 g into a 5-pressure stirring tank. Charge 3.5 liters of toluene as a solvent. The inside of the stirring tank is replaced with nitrogen, and the temperature is raised to 180°C while stirring. Stir at 180°C for 2 hours to blend the polymer.
After cooling to below the boiling point, it is precipitated into methanol 20 to obtain a polymer.

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Claims (1)

[Claims] 1. Density 0.915 to 0.955, viscosity average molecular weight 150,000 to 50
30 to 60 parts by weight of polyolefin A having a weight average molecular weight/number average molecular weight of 2 to 6, and a density of 0.940 to 0.977,
Polyolefin ^A and polyolefin B have the general formula Mg(OR ¹ ) _n An oxygen-containing organic compound of magnesium represented by _2-o (wherein R ¹ represents an alkyl group, aryl group, or cycloalkyl group, X ¹ represents a halogen atom, and m represents 1 or 2) and the general formula
TiX ² _o (OR ² ) _4-o (wherein, X ² represents a halogen atom, R ² represents an alkyl group, aryl group, or cycloalkyl group, and n represents a number from 1 to 4) The reaction product with a titanium halogen compound or the above-mentioned oxygen-containing organic compound of magnesium with the general formula _Ti ( ^OR3 ) ^kX34 _-k (wherein ^R3 represents an alkyl group, an aryl group or a cycloalkyl group, X ³ represents a halogen atom, k represents a number from 1 to 4) and the general formula AlR ⁴ _p X ⁴ _3-p (wherein R ⁴ is an alkyl group or an aryl group) or a cycloalkyl group, X ⁴ represents a halogen atom, and p represents a number of 0<p<3), and a reaction product with an aluminum halogen compound represented by the general formula AlR ⁵ _q X ⁵ _3-q (wherein, R ⁵ represents an alkyl group, an aryl group, or a cycloalkyl group, X ⁵ represents a halogen atom, and q represents a number from 1 to 3). Using the produced ethylene homopolymer or copolymer of ethylene and other α-olefin, and (viscosity average molecular weight of polyolefin A)/(viscosity average molecular weight of polyolefin B)
Melt index is 0.05 to 10 to 50
A polyolefin composition having an outflow ratio of 0.5 and 50 or more.