JP3449027B2 - Hollow molded product made of olefin polymer composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow molded article made of an olefin polymer composition comprising a propylene-based block copolymer composition, and more particularly to a propylene-based block copolymer. The present invention relates to a hollow molded article made of a polymer composition and made of an olefin polymer composition which is extremely excellent in impact resistance, impact resistance to whitening, and appearance. 2. Description of the Related Art A composition using a conventional propylene-based block copolymer has many excellent properties such as rigidity, impact resistance, heat resistance, hygiene, moldability and the like. The hollow containers having a decorative property with an appearance, particularly a pearly feeling, have been demanded from the market. As a technique related to the hollow container having a decorative property having a pearly feeling, in a synthetic resin container having a pearl decoration effect to obtain an appearance similar to pearl luster, a mica-based or titanium-based material for providing a pearl decoration effect A pearl decoration in which a main body is constituted by an outer layer formed of a transparent synthetic resin mixed with a predetermined amount of pearl essence, and an inner layer formed of an opaque synthetic resin of a desired color laminated inside the outer layer. Container (JP-B-53-41596), low-density polyethylene or high-density polyethylene,
And an outer layer made of block polypropylene, a laminate having an inner layer containing a coloring agent in polypropylene, the outer layer surface is roughened, and the laminate,
Further, there is known a colored multilayer blow-molded container (JP-A-6-199333), which has an intermediate layer made of polypropylene, wherein at least one of the outer layer, the inner layer and the intermediate layer contains pearl essence. Have been. [0003] However, a container obtained by blow molding using a transparent synthetic resin into which a predetermined amount of the pearl essence is mixed and a layer in which at least one of the outer layer, the inner layer and the intermediate layer contains the pearl essence is used. However, there remains a problem that spider marks or weld marks are conspicuous and the appearance is not excellent. Further, there remains a problem that the hollow container is not economical because the expensive pearl essence is essential. SUMMARY OF THE INVENTION [0004] An object of the present invention is to provide rigidity, impact resistance, heat resistance, hygiene, and molding of a hollow molded article using a composition using a conventional propylene-based block copolymer. It is made of a specific propylene-based block copolymer composition from which spider marks or weld marks are inconspicuous, and a hollow molded article excellent in decorativeness and economic efficiency is obtained while making use of many excellent properties such as properties. An object of the present invention is to provide a hollow molded article made of an olefin polymer composition. [0005] The present invention has the following arrangement. (1) In a block copolymer comprising a propylene homopolymer component and an ethylene-propylene copolymer component, the intrinsic viscosity [η] _PP of the homopolymer component, the intrinsic viscosity [η] _RC of the copolymer component, and the weight of the homopolymer component And the weight of the copolymer component is W _PP and W _RC , respectively, the product of the intrinsic viscosity ratio of the copolymer component and the homopolymer component and the weight ratio of the homopolymer component and the copolymer component (([η] _RC / [η] _PP ) × (W _PP / W _RC )) is in the range of 0.2 to 2.0, and the ratio of the melt flow rate of the homopolymer component to the melt flow rate of the copolymer component is in the range of 0.3 to 4. A hollow molded article made of an olefin polymer composition using a propylene-based block copolymer composition [A] having a copolymer component [η] _RC of 6.5 or less. The present invention will be described in detail below. The constitutional feature of the propylene-based block copolymer composition [A] used in the present invention is a relational expression ([η] _RC / [η] _PP ) × (W _PP ) between the content of the homopolymer component and the copolymer component and the intrinsic viscosity.
/ W _RC) in the range of 0.2 to 2.0, more preferably in the range of 0.3 to 1.9, and the ratio of melt flow rate of the melt flow rate and a copolymer component of the homopolymer component 0. In the range of 3-4, more preferably 0.3-
3.5, the intrinsic viscosity [η] of the copolymer component
_RC is 6.5 or less, more preferably 5.0 or less. Propylene copolymer composition [A] in the above range
The hollow molded article using is excellent in decorativeness having a pearly feeling. If the ratio is outside the above range, for example, the ratio of intrinsic viscosity [η] _RC / [η] _PP of the homopolymer component and the copolymer component is largely out of the range of 0.2 to 2.0, the composition is used. Although the improvement in the impact whitening resistance of the hollow molded article was observed, it was inadequate, particularly the bending resistance to whitening was insufficient, and the hollow molded article using the composition did not have a pearly feeling. Not excellent. The content of each of the above components is preferably in the range of 30 wt% to 80 wt% of the copolymer component. More preferably, it is in the range of 35 wt% to 75 wt%. If the composition is out of the above range, the whitening resistance to impact and the whitening resistance to bending are insufficient. In particular, a hollow molded product using a composition much less than 30 wt% has insufficient impact resistance at low temperatures, and a composition exceeding 80 wt% has poor fluidity of powder produced by polymerization, and a propylene-based block. There is a problem in the production of the copolymer, and a hollow molded article using the composition has insufficient rigidity and a problem in shape retention. The ethylene content of the copolymer component is 25 watts in terms of excellent impact resistance, impact whitening resistance, and whitening resistance to bending.
It is preferably in the range of t% to 65% by weight. More preferably, it is in the range of 30 wt% to 65 wt%. Further, a propylene-based block copolymer composition in which the ethylene content of the copolymer component is within the above range is preferable in that a hollow molded article using the composition has a pearly appearance. In particular, a hollow molded product using a composition that greatly exceeds the range of 65% by weight has problems in pinch-off strength and weld strength, and has poor impact resistance. [0009] The melt flow rate of the propylene block copolymer composition [A] used in the present invention is 0.1 to 0.1 in terms of productivity and moldability of a hollow molded article using the composition.
4 g / 10 min is preferred, and more preferably 0.3 to 10 g / min.
2 g / 10 min. In the propylene-based block copolymer composition [A] used in the present invention, a homopolymer component is first formed from crystalline polypropylene, and the intrinsic viscosity ([η] _PP ) and melt flow rate (MFR _PP ) of the polymer component are determined. Measured directly. Subsequently, the intrinsic viscosity ([η] _RC ) and melt flow rate (M) of the copolymer component, which is a propylene-ethylene random copolymer, are formed.
FR _RC ) cannot be measured directly. Then, the intrinsic viscosity [η] _PP of the entire copolymer composition was measured, and the intrinsic viscosity ([η]
_WHOLE ) minus the homopolymer component's weight fraction multiplied by the homopolymer component's intrinsic viscosity [η] _PP , and dividing this by the total composition, that is, the copolymer component's fraction, gives the quotient of the copolymer portion. Viscosity [η] _RC is required. That is, it is obtained from the following (Equation 1). [Equation 1] The melt flow rate (MFR _RC ) of the copolymer component is determined by measuring the melt flow rate (MFR _WHOLE ) of the entire copolymer composition and the melt flow rate (MFR _PP ) of the homopolymer. More required. Equation 2 Wherein the fraction of the copolymer component (W _RC / 100)
Can be determined by a conventionally known infrared analysis method or the like. The propylene-based block copolymer composition [A] used in the present invention may be obtained by any method.
For example, a blend obtained by adding EPR having an intrinsic viscosity ratio defined in the present invention to a homopolymer may be used. Further, a blend in which an ethylene-propylene random copolymer polymerized using a titanium-containing solid catalyst component is added to a homopolymer may be used. However, the method of adding EPR is disadvantageous from the economical point of view such as the high price of EPR and the necessity of a blending step. The method of adding EPR is EPR.
There is a problem that the quality cannot be stabilized due to poor dispersibility. A preferred method for obtaining the propylene-based block copolymer of the present invention is a method for producing by a polymerization. The propylene-based block copolymer composition [A] of the present invention obtained by polymerization is preferable because it does not require EPR and thus is inexpensive, and does not require a blending step, so that a stable product can be obtained. Hereinafter, a production method by polymerization will be exemplified. The production method by polymerization of the propylene-based block copolymer composition (A) used in the present invention is carried out by polymerization using a solid catalyst containing titanium, magnesium, halogen and the like, a catalyst obtained by combining an organoaluminum compound and an organosilicon compound. You. That is, the amount of the olefin polymer produced by the preactivated catalyst treated with a small amount of olefin in the presence of the titanium-containing solid catalyst component, the organoaluminum compound and, if necessary, the electron donor is reduced to the titanium-containing solid catalyst component 1
The prepolymerization is carried out in an amount of 0.1 to 100 grams per gram, then the main polymerization of propylene in the presence of the organoaluminum and, if necessary, the electron donor in the presence of the preactivated catalyst, followed by It is preferable to perform random copolymerization of propylene and ethylene to obtain a propylene-based block copolymer powder. The organoaluminum and electron donor used in the preactivation and main polymerization may be the same or different types. As the titanium-containing solid catalyst in the above-mentioned method for producing a propylene-based block copolymer, any known one can be used as long as the titanium compound is supported on a magnesium compound. For example, a magnesium compound-alcohol solution is sprayed, the solid component is partially dried, and then the dried solid component is treated with a titanium halide and an electron donating compound to obtain a titanium-containing solid catalyst component (JP-A-3-119003). Is mentioned. Also, a titanium-containing solid catalyst component obtained by dissolving a magnesium compound in tetrahydrofuran / alcohol / electron donor and treating a magnesium carrier precipitated with TiCl ₄ alone or in combination with an electron donor with a titanium halide and an electron donating compound. (JP-A-4-103604). As the organoaluminum compound used in the polymerization of the present invention, the general formula is AlR ⁵ _M R ⁶ _N X _{3- (M + N)}
(Wherein R ⁵ and R ⁶ represent a hydrocarbon group or an alcohol group, X represents a halogen, and M and N represent 0 <M + N ≦ 3
Represents an arbitrary number. ) Can be used. Specifically, trimethyl aluminum, triethyl aluminum, tri-n-propyl aluminum, tri-n-butyl aluminum, tri-i-butyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride, methyl aluminum sesquichloride, di-n- Examples thereof include propylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum iodide, and ethoxydiethylaluminum. These organoaluminum compounds can be used alone or in combination of two or more. The organosilicon compounds used in the polymerization according to the present invention, the general formula ^{_{R 2 X R 3 Y Si (}} OR 4) Z ( wherein R ² _X, R
⁴ is a hydrocarbon group, R ³ is a hydrocarbon group or a hydrocarbon group containing a hetero atom, X + Y + Z = 4, 0 ≦ X ≦
2, 1 ≦ Y ≦ 3, 1 ≦ Z ≦ 3) can be used. Specifically, methyltrimethoxysilane, t
-Butyltrimethoxysilane, t-butyltriethoxysilane, phenyltriethoxysilane, methylethyldimethoxysilane, methylphenyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane,
Examples thereof include diisopropyldimethoxysilane, diisobutyldimethoxysilane, di-t-butyldimethoxysilane, diphenyldimethoxysilane, trimethylmethoxysilane, and trimethylethoxysilane. Preferred are diisobutyldimethoxysilane, diisopropyldimethoxysilane, di-t-butyldimethoxysilane and diphenyldimethoxysilane. These organosilicon compounds can be used alone or in combination of two or more. The polymerization of propylene for producing the homopolymer component of the propylene-based block copolymer of the present invention can be carried out by any of slurry polymerization, bulk polymerization and gas phase polymerization using the above-mentioned titanium-containing solid catalyst or the like. However, the polymerization method of the copolymer component in the latter stage is preferably a gas phase polymerization method. In a slurry polymerization method or a bulk polymerization method, a copolymer component is eluted in a solution, and it is difficult to continue stable operation, and the effect of the present invention is not sufficiently exerted. The improvement effect of the present invention is remarkable in a combination of a gas phase polymerization method and a gas phase polymerization method. The polymerization conditions vary depending on the type of polymerization. In the case of the gas phase polymerization method, a titanium-containing catalyst component, an organoaluminum component and an organosilicon compound are mixed at a polymerization temperature of 20 to 1 while mixing and stirring a fixed amount of powder.
Under conditions of 20 ° C., preferably 40 to 100 ° C., polymerization pressure atmospheric pressure to 100 kg / cm ² G, preferably 5 to 50 k
The homopolymer component is supplied under the conditions of g / cm ² G to polymerize the homopolymer component. It is effective to adjust the molecular weight of the homopolymer component by adding a molecular weight modifier such as hydrogen during polymerization. After the homopolymer component is polymerized, a part of the produced powder is extracted and used for measurement of intrinsic viscosity, measurement of MFR, and determination of polymerization yield per unit weight of catalyst. Subsequent to the polymerization of the homopolymer component, the copolymer component is heated at a polymerization temperature of usually 20 to 120 ° C., preferably 40 to 100 ° C., at a polymerization pressure of atmospheric pressure to 100 kg.
/ Cm ² G, preferably 5 to 50 kg / cm ² G, to produce a propylene-based random copolymer. The ethylene content in the copolymer component of the present invention is controlled by controlling the gas molar ratio of the ethylene monomer and the propylene monomer in the comonomer gas.
The ethylene content in the copolymer component is from 25 wt% to 65 w
Adjusted to t%. The weight of the copolymer component with respect to the weight of the homopolymer component can be adjusted to 30 wt% to 80 wt% by adjusting the polymerization time or using a polymerization activity regulator for a catalyst such as carbon monoxide or hydrogen sulfide. It is adjusted to become. In addition, the molecular weight of the copolymer component is adjusted during polymerization of the copolymer by adding a molecular weight regulator such as hydrogen so that the intrinsic viscosity and MFR of the copolymer component meet the requirements of the present invention. The polymerization may be any of a batch system, a non-continuous system, and a continuous system, but a continuous polymerization is industrially preferable. After completion of the main polymerization, the monomer can be removed from the polymerization system to obtain a particulate polymer. The obtained polymer is used for measurement of intrinsic viscosity, measurement of MFR, measurement of ethylene content, and determination of polymerization yield per unit weight of catalyst. The propylene-based block copolymer composition [A] used in the present invention may optionally contain additives used in polyolefins. For example, antioxidants, neutralizers, weathering agents, ultraviolet absorbers, antistatic agents, pigments (excluding pearl essence), crystal nucleating agents, olefin elastomers and rubbers, crystalline propylene homopolymer, crystalline propylene -Examples thereof include α-olefin copolymers, low-density polyethylene, linear low-density polyethylene, and high-density polyethylene. As a method for obtaining a hollow molded article using the propylene-based block copolymer composition [A] of the present invention, a direct blow molding method can be exemplified. As the direct blow molding method, the propylene-based block copolymer composition [A] is melt-extruded using an extruder to form a parison, and the parison is placed in a blow molding mold maintained at 60 ° C. or lower, and the parison is placed therein. To pressurized air (0.5 to 1
A molding method in which air pressure is applied until the shape is fixed by blowing MPa) can be exemplified. The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited by these specific examples. The characteristics used in the following Examples and Comparative Examples were evaluated by the following methods. (1) Melt flow rate (230 ° C; 21.18N)
(Hereinafter sometimes abbreviated as MFR): JIS K72
10 (1976) test conditions (unit: g / 10 min). (2) Intrinsic viscosity [η]: The viscosity determined when the polymer is in an extremely dilute state in a given solvent at a temperature determined for the polymer. In the case of the present invention, the viscosity was determined at 135 ° C. using tetralin (tetrachloronaphthalene) as a solvent and using an automatic viscosity meter AVS2 manufactured by Mitsui Toatsu Co. (unit: dl / g). (3) Impact resistance: 500 cc of water was put into a container, sealed and left in a low temperature room at 5 ° C. for 8 hours or more.
It was dropped on a concrete pavement from a height of 1.5 m, and the state of destruction was observed and evaluated. A to E in the evaluation results have the following meanings: A: The subject is not broken at all by 10 drops. B: 80% of the specimen does not break after 10 drops. C: The subject did not crack at all five times, and all were broken by ten times. D: 50% of the test object was cracked by dropping up to 5 times. E: All of the test pieces were broken by 1 to 3 drops. (4) Decorativeness: The appearance of the hollow molded container is visually determined. A: A pearly feeling is remarkably observed. B: A pearly feeling is observed. C: A pearly feeling is not seen only in a white feeling. (5) Impact whitening resistance: A container is laid horizontally in an environment of 20 to 25 ° C., and a gun barrel (190 g) having a tip radius of 6.35 mm is applied to the center of the body of the container to apply a load of 500 g. The diameter of a whitened surface generated around a dropping core from a height of 50 cm is measured. A: Scratches are seen in the hammer but no whitening is seen. B: Whitening of less than 8 mmφ occurs in the hammer. C: Whitening of 8 to 15 mmφ occurs in the hammer portion. D: Whitening exceeding 15 mmφ occurs in the striker portion. (6) Formability: A molten parison is extruded at a molding temperature of 200 ° C., a screw diameter of 50φ, and a screw rotation speed of 40 rpm (a die diameter of 21 mm and a core diameter of 19).
mm) The speed at which the parison hangs down to 12 cm and 50 cm is measured, and the difference is determined by the difference between the hang speeds (speed up to 50 cm / speed up to 12 cm). A: A material having a small drawdown and a speed difference of less than 5%. B: A material having a drawdown speed difference of 5 to 20%. C: A material having a drawdown speed difference of more than 20% (defective molding). (Examples 1 to 9 and Comparative Examples 1 to 9) 100 parts by weight of a propylene block copolymer having each melt flow rate and each ethylene composition shown in Tables 1 to 4 described below, and tris (2,4 -Di-t-butylphenyl) phosphite 0.05 parts by weight, tetrakis [methylene (3,5-di-
-t-butyl-4-hydroxyhydrocinnamate)] 0.05% by weight of methane and 0.1% of calcium stearate
Parts by weight using a Henschel mixer, 250 ° C
The mixture was melt-kneaded and extruded with an extruder set to give a pellet-shaped composition. The composition was subjected to a blow molding machine [SN
50A (manufactured by Placo Co.)], the extruder was set at a temperature of 200 ° C., and a parison was extruded. This parison was blown in a mold adjusted to 30 ° C. to form a hollow container (body of the body). (The average thickness is 0.8mm and the internal volume is 600ml)
Was molded. Tables 1 to 4 show the characteristics of the hollow container. In Examples 1 to 9 shown in Tables 1 and 2, a homopolymer component was obtained from a block copolymer comprising a propylene homopolymer component obtained by a gas phase polymerization method followed by an ethylene-propylene copolymer component. When the intrinsic viscosity [η] PP of the copolymer component and the intrinsic viscosity [η] RC of the copolymer component and the weight of the homopolymer component and the copolymer component are W _PP and W _RC , respectively, the intrinsic viscosity of the copolymer component and the homopolymer component is Product of the ratio and the weight ratio of the homopolymer component to the copolymer component [([η] RC / [η] PP) × (W
_PP / W _RC)] is in the range of 0.2 to 2.0, and the homopolymer component MFR (230 ℃; 21.18N) and MFR (230 ° C. copolymer component; ratio of 21.18 N) is 0 Within the range of 0.3 to 4.0, the [η] RC of the copolymer component is 6.5 or less, the ethylene content in the copolymer component is 25 to 65% by weight, and the weight of the copolymer component is 30 to 70%.
% By weight, MFR (230 ° C .; 21.18 N) 0.1 to
A hollow container obtained by a blow molding method using a propylene-based block copolymer composition of 4 g / 10 min is excellent in impact resistance, impact whitening resistance, moldability, and has an extremely decorative pearly feel. Has the appearance. On the other hand, in Comparative Examples 1 to 9 shown in Tables 3 and 4, the product of the ratio of the intrinsic viscosity of the copolymer component to the homopolymer component and the weight ratio of the homopolymer component to the copolymer component [([η] RC / [η] PP) × (W _PP / W _RC )] is 0.
It is a hollow container using a composition of less than 2 or more than 2, having no pearly appearance with excellent decorativeness, and not good impact whitening resistance. The olefin hollow molded article of the present invention has an economical effect such as rigidity, impact resistance, heat resistance, hygiene, moldability, etc., and a spear mark or a weld mark, and has a pearly appearance without being noticeable. , It can be usefully used for various purposes such as foods, daily necessities, general industrial products, and the like. [Table 1] [Table 2] [Table 3] [Table 4]

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 297/00-298/08

Claims (1)

(57) [Claims 1] In a block copolymer comprising a propylene homopolymer component and an ethylene-propylene copolymer component, the intrinsic viscosity [η] _PP of the homopolymer component and the intrinsic viscosity of the copolymer component [Η] When the weight of _RC and its homopolymer component and the weight of the copolymer component are W _PP and W _RC , respectively, the product of the ratio of the intrinsic viscosity of the copolymer component to the homopolymer component and the weight ratio of the homopolymer component to the copolymer component (([Η] _RC / [η] _PP ) × (W _PP / W _RC ))
Is in the range of 0.2 to 2.0, the ratio of the melt flow rate of the homopolymer component to the melt flow rate of the copolymer component is in the range of 0.3 to 4, and the [η] _{RC of the} copolymer component is A hollow molded article made of an olefin polymer composition comprising the propylene-based block copolymer composition [A], having a molecular weight of 6.5 or less.