JPS6367811B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ethylene polymer composition for pipes, and more specifically, it has specific physical properties such as low-temperature impact resistance,
This invention relates to an ethylene polymer composition for pipes that has excellent environmental stress cracking resistance (hereinafter abbreviated as ESCR), appearance, etc. Ethylene-based polymers have excellent corrosion resistance, insulation properties, piping workability, etc., and have thus far been widely used as materials for various pipes such as flexible electrical conduits.
The materials used for such pipes must have excellent low-temperature impact resistance, ESCR, compression recovery, etc., and must be able to be made thin in order to save resources. However, the various ethylene polymers for pipes that have been used in the past have not been able to fully satisfy the above-mentioned high performance requirements. Therefore, as a result of intensive research on pipe materials that satisfy the above performance, the present inventor discovered that a specific composition consisting of two types of ethylene polymers satisfies these required performances, and based on this knowledge, the present inventor The invention was completed. That is, the present invention provides (A) an intrinsic viscosity of 0.5 to 1.7 dl/
g, ethylene homopolymer or copolymer with a density of 0.960 to 0.980 g/cm ³ (hereinafter referred to as component (A)) 35
~70% by weight and (B) intrinsic viscosity 6~12dl/g, density
0.935-0.952g/ ^cm3 ethylene copolymer (hereinafter referred to as
(B) It is called component. ) 65 to 30% by weight, an ethylene polymer composition for pipes having an intrinsic viscosity of 3.7 to 4.5 dl/g and a density of 0.957 to 0.967 g/cm ³ . Component (A) of the present invention has an intrinsic viscosity (hereinafter abbreviated as [η]) of 0.5 to 1.7 dl/g, preferably 0.6 to 1.5 dl/g.
g, density 0.960 to 0.980 g/cm ³ , preferably 0.964 to
It is 0.978 g/cm ³ and is an ethylene homopolymer or a copolymer of ethylene and other monomers. In order to improve the low-temperature impact resistance of the composition of the present invention, it is preferable to use an ethylene homopolymer as component (A). In addition, when using a copolymer of ethylene and another monomer as component (A), α-olefin having 3 to 8 carbon atoms can be used as the monomer, such as propylene, butene-1, hexene-1, etc. 1, octene-1, etc. The content of other α-olefins in the copolymer should be less than 5% by weight. If the amount is 5% by weight or more, the low-temperature impact resistance of the composition cannot be sufficiently improved. If [η] of component (A) is less than 0.5 dl/g, the impact resistance of the composition will decrease, and if it exceeds 1.7 dl/g, the ESCR will decrease, which is not preferable. Furthermore, if the density of component (A) is less than 0.960 g/cm ³ , the impact resistance and ESCR of the composition will decrease. Next, as described above, the component (B) of the present invention is [η]
is an ethylene copolymer with a density of 6 to 12 dl/g and a density of 0.935 to 0.952 g/cm ³ . Here, as the ethylene copolymer, a copolymer of ethylene and α-olefin having 3 to 8 carbon atoms, such as propylene, butene-1, hexene-1, octene-1, etc., is used, and other α-olefin-containing copolymers are used. The amount is 0.1-10% by weight,
Preferably it should be between 0.3 and 5% by weight. If the content of other α-olefins is less than 0.1% by weight, the ESCR of the composition will decrease, while if it exceeds 10% by weight, compression recovery properties will decrease, which is not preferable. If [η] of component (B) is less than 6 dl/g, the ESCR of the composition will decrease, and if it exceeds 12 dl/g, the compatibility will be poor and the resulting composition will have poor appearance. . Moreover, if the density is less than 0.935 g/cm ³ , the compressibility of the composition decreases, making it difficult to reduce the thickness. On the other hand, when it exceeds 0.952 g/cm ³ , ESCR decreases. Regarding the blending ratio of the above-mentioned (A) component and (B) component in the composition of the present invention, the (A) component is 35 to 70% by weight, preferably 40 to 65% by weight, the (B) component is 65 to 30% by weight, Preferably it should be between 60 and 35% by weight. If the amount of component (A) exceeds 70% by weight, the resulting composition will have poor compatibility and the surface of the molded product will be defective.
Moreover, if it is less than 35% by weight, the fluidity will be significantly reduced and the appearance of the molded product will be poor, which is not preferable. Similarly, if the amount of component (B) is less than 30% by weight, the surface of the molded product will be poor due to poor compatibility. Moreover, if it exceeds 65% by weight, the fluidity of the composition will be significantly reduced and the appearance will be poor. The ethylene polymer composition obtained by blending components (A) and (B) as described above has an [η] of 3.0 to 4.6 dl/
g, preferably 3.5 to 4.5 dl/g, and the density is
It is 0.957 to 0.965 g/cm ³ . Here [η] is 3.0
If it is less than dl/g, the composition will have poor low temperature impact properties.
The ESCR will be lower, making thinning impossible. On the other hand, if it exceeds 4.6 dl/g, molding becomes difficult. Also, if the density is less than 0.957g/ ^cm3 ,
Compression resilience of the composition decreases, making it difficult to reduce the thickness, and if it exceeds 0.965 g/cm ³ , the ESCR decreases, which is not preferable. The compositions of the present invention can be manufactured by various methods. For example, there is a method in which components (A) and (B) are manufactured separately and then manufactured by a commonly used blending method, and a method in which they are manufactured continuously by a two-step polymerization method. Particularly preferred is the latter method, ie, the two-stage polymerization method. To explain the method for producing the composition of the present invention by a two-stage polymerization method, first, in the first stage polymerization, (A)
Manufacture the ingredients. The reaction temperature at this time is 70-95
℃ and reaction pressure of 0.5 to 15 Kg/cm ² are appropriate. Next, component (B) is produced by second stage polymerization. The reaction temperature at this time is the same as or lower than that in the first stage polymerization, and the pressure is 0.5 to 15 kg/cm ² . An ethylene polymer composition having the above-mentioned physical properties is produced by adjusting the method of supplying raw materials at each stage. The catalyst used in this two-step polymerization method is a catalyst whose main components are a solid catalyst component containing at least titanium, magnesium, and halogen, and an organic aluminum compound component. Here, the solid catalyst component containing at least titanium, magnesium and halogen is
It is a composite solid formed by contacting a magnesium compound and a halogen-containing titanium compound or an addition compound of this compound and an electron donor in a stepwise or primary manner, and various known solids can be used without particular limitation. be able to. For example, it can be obtained by reacting a magnesium compound and a chlorine-containing titanium compound in a hydrocarbon solvent with stirring. Some other manufacturing examples include JP-A-46-34092, JP-A-50-32270, JP-A-50-95382, JP-A-54-41985, JP-A-55
―729, JP-A-55-13709, JP-A-57-12006
There are methods disclosed in various publications such as JP-A-57-141409. Magnesium compounds that can be used in the production of solid catalyst components include various compounds that are commonly used as carriers for Ziegler-type catalysts. For example, magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride, magnesium hydroxide, magnesium oxide, magnesium sulfate, magnesium carbonate, hydroxymagnesium chloride, hydroxymagnesium bromide, hydroxymagnesium iodide, etc. Alkoxymagnesium such as halogenated hydroxymagnesium, methoxymagnesium, ethoxymagnesium, propoxymagnesium, butoxymagnesium, methoxymagnesium chloride, methoxymagnesium bromide, ethoxymagnesium chloride, ethoxymagnesium bromide, propoxymagnesium chloride, propoxymagnesium bromide, butoxymagnesium chloride, butoxy Alkoxymagnesium halides such as magnesium bromide, allyloxymagnesium halides such as allyloxymagnesium, allyloxymagnesium chloride, allyloxymagnesium bromide, methylmagnesium chloride, methylmagnesium bromide, ethylmagnesium chloride, ethylmagnesium bromide,
Examples include alkylmagnesium halides such as propylmagnesium chloride, propylmagnesium bromide, butylmagnesium chloride, butylmagnesium bromide, and mixtures thereof. Furthermore, although the magnesium compound described above can be used as it is, it is more preferable to use one modified with a silicon halide or the like.
For example, a mixture of magnesium dialkoxide and magnesium sulfate modified with silicon tetrachloride and alcohol can be suitably used (Japanese Patent Application Laid-open No. 40724/1983). The halogen-containing titanium compound that can be used for producing the solid catalyst component may be a halogenated compound of divalent, trivalent or tetravalent titanium. Examples of the halogen include bromine and iodine, but chlorine is particularly preferred. For example, titanium tetrachloride (TiCl ₄ ), titanium trichloride (TiCl ₃ ), adduct of titanium trichloride and aluminum chloride (TiCl ₃ 1/3AlCl ₃ ), dichloromethoxytitanium (CH ₃ OTiCl ₂ ), trichloroethoxytitanium (C ₂ H ₅ OTiCl ₃ ), trichloropropoxy titanium (C ₃ H ₇ OTiCl ₃ ), dichlorodipropoxy titanium ((C ₃ H ₇ O) ₂ TiCl ₂ ), dichlorodiethoxy titanium ((C ₂ H ₅ O) ₂ TiCl ₂ ), monochlorotriethoxytitanium ((C ₂ H ₅ O) ₃ TiCl), etc. In the solid catalyst component (A), the above compounds are desirably blended so that the halogen/titanium ratio is in the range of 3 to 200 (mole ratio) and the magnesium/titanium ratio is in the range of 3 to 90 (mole ratio). Next, the organoaluminum compound component is a compound having at least one aluminum-carbon bond in the molecule, for example, the general formula R ₃ Al, R ₂ AlX,
RAlX ₂ , R _{2 AlOR} , RAl(OR)X, R ₃ Al ₂ Or it may be different.Also,
X represents a halogen atom. ) may be used alone or in combination. Preferred examples of this compound include diethylaluminum monochloride, diisopropylaluminum monochloride, diisobutylaluminum monochloride, dioctylaluminum monochloride, ethylaluminum dichloride, isopropylaluminum dichloride, ethylaluminum sesquichloride, and the like. The amount of the organoaluminum compound component to be used should be 0.1 to 1000 times the amount of the titanium compound in the solid catalyst. Catalysts containing both of the above-mentioned components as main components usually have the ability to produce 80 to 400 g of ethylene polymer per 1 mg of titanium. Among the above-mentioned catalysts, especially JP-A-54-161691
No., JP-A-55-40724 and JP-A-55-149307
The catalysts disclosed in each of the publications of No. 1 are suitable. Furthermore, various polymerization methods such as suspension polymerization, solution polymerization, and gas phase polymerization can be applied, and the reaction can be carried out not only continuously but also batchwise. Furthermore, in carrying out the polymerization reaction, an inert solvent such as pentane, n-hexane, cyclohexane, heptane, benzene, toluene, etc. can be used. The ethylene polymer composition of the present invention has excellent low-temperature impact resistance, ESCR, compression recovery properties, appearance, etc. Therefore, this composition can be made thinner than conventional products when molded, and has sufficiently satisfactory physical properties even when it is about 0.8 to 0.9 times the thickness of conventional products (generally 1 to 3 mm thick). have. Therefore, the composition of the present invention can be very suitably used for pipes, especially for resin flexible electrical conduits. Next, the present invention will be explained by examples. Examples 1 to 3 and Comparative Examples 1 to 3 (1) Production of solid catalyst component 1.0 g (8.8 mmol) of magnesium diethoxide and 1.06 g (8.8 mmol) of commercially available anhydrous magnesium sulfate were suspended in 50 ml of n-heptane. let me,
Furthermore, 1.5 g (8.8 mmol) of silicon tetrachloride and 1.6 g (35.2 mmol) of ethanol were added and heated to 80°C.
A time reaction was performed. Next, 5 ml of titanium tetrachloride (45
mmol) and reacted at 98°C for 3 hours. After the reaction, the cooled stationary supernatant was removed by decanting.
Next, add 100ml of n-heptane and stir.
After washing operations of standing still and removing supernatant liquid three times, n
- 200ml of heptane was added to obtain a dispersion of solid catalyst components. The amount of titanium supported on this product was determined by a colorimetric method and was found to be 42 mg-Ti/g-support. (2) Production of ethylene polymer composition After purging a 7-volume stainless steel autoclave with dry nitrogen, 50% of dry hexane and 0.26 mmol of the solid catalyst component produced in (1) above (titanium concentration
0.096 mmol/), triethylaluminum
0.6 mmol and 7.2 mmol of diethylaluminum chloride were added. Next, hydrogen was metered so that the polyethylene had the intrinsic viscosity [η] shown in Table 1, and ethylene was continuously supplied so that the total pressure of the reactor was 8.3 Kg/cm ² G. The reaction was carried out with stirring for a minute to produce component (A) (first step). After cooling the reactor, degassing it and replacing it with dry nitrogen, add 2.3 ml of dry hexane, add hydrogen and 1-1 butene, raise the temperature to 80°C, continuously feed ethylene, and remove component (B). obtained (second stage). After the reaction was completed, the obtained ethylene polymer composition was washed, dried, granulated, and then processed into a pressed sheet or pipe and its physical properties were measured. The results are shown in Table 1. Example 4 (1) Production of catalyst 10.0 g (88 mmol) of magnesium diethoxide was dispersed in 150 ml of n-heptane, and 1.09 g (11 mmol) of silicon tetrachloride and isopropanol were dispersed.
1.32 g (22 mmol) was added at room temperature, the temperature was raised to 80°C, and the reaction was carried out for 2 hours. Next, 25 ml of titanium tetrachloride was added to this dispersion, and the reaction was further carried out at approximately 100°C for 3 hours. After cooling, the solution was washed with n-heptane until no free chlorine ions were detected, and finally, 2 portions of n-heptane were added to form a suspension. The titanium content of the solid component in this suspension is
It was 78mg-Ti/g-carrier. (2) Production of ethylene polymer composition In Example 1, the above solid catalyst component was
An ethylene polymer composition was obtained in the same manner as in Example 1, except that the material obtained in (1) was used and propylene was used in the prescribed amount shown in Table 1 instead of butene-1. The results are shown in Table 1. Example 5 In Example 4, the reaction temperature was set to 90°C in the first stage.
An ethylene polymer composition was obtained in the same manner as in Example 4, except that the temperature was 70°C in the second stage and that butene-1 was used in the prescribed amount in Table 1 instead of propylene. The results are shown in Table 1. Example 6 An ethylene polymer composition was obtained in the same manner as in Example 4, except that butene-1 was used in the predetermined amount shown in Table 1 together with ethylene in the first step. The results are shown in Table 1. Comparative Examples 4 to 6 Ethylene polymer compositions were obtained in the same manner as in Example 4, except that butene-1 was used in the prescribed amount shown in Table 1 instead of propylene. The results are shown in Table 1. Comparative Example 7 An ethylene polymer composition was obtained in the same manner as in Example 1, except that butene-1 was used in the prescribed amount in Table 1 together with ethylene in the first stage. The results are shown in Table 1.

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Claims (1)

[Claims] 1 (A) Intrinsic viscosity 0.5 to 1.7 dl/g, density 0.960 to
0.980 g/ ^cm3 of ethylene homopolymer or copolymer 35-70% by weight and (B) intrinsic viscosity 6-12 dl/
g, ethylene copolymer with density 0.935-0.952 g/ ^cm3
Intrinsic viscosity 3.7-4.5dl/g, consisting of 65-30% by weight
Ethylene polymer composition for pipes with a density of 0.957 to 0.965 g/ ^cm3 . 2 (B) Intrinsic viscosity 6-12 dl/g, density 0.935-0.952
g/cm ³ of ethylene copolymer has 3 to 8 carbon atoms.
The composition according to claim 1, which is a copolymer of olefin and ethylene. 3 (A) Intrinsic viscosity 0.5 to 1.7 dl/g, density 0.960 to
A patent consisting of an ethylene homopolymer of 0.980 g/cm ³ and (B) a copolymer of ethylene with an α-olefin having 3 to 8 carbon atoms and an intrinsic viscosity of 6 to 12 dl/g and a density of 0.935 to 0.952 g/cm ³ A composition according to claim 1.