JP2855459B2 - Ethylene polymer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ethylene polymer composition, and
The present invention relates to an ethylene polymer composition having improved properties such as gloss and moldability.

[Conventional technology]

As the linear polyethylene, high-density polyethylene,
There are medium-density polyethylene and linear low-density polyethylene, but these resins are widely used as molded products by injection molding, hollow molding, sheet molding, rotational molding, extrusion molding, film molding, etc. due to their unique properties. Has been provided. In many of these molding fields, a nucleating agent is added to the resin in order to improve the physical properties and moldability of the resin.

Especially in the field of molded products, product transparency, gloss,
It is known that benzylidene sorbitol or a specific nucleus-substituted product thereof is blended as a nucleating agent for the purpose of improving dimensional stability, rigidity, shortening a molding cycle by improving crystallization speed, and the like. (JP-A-58-17135, JP-A-58-219274,
JP-A-61-133252).

However, although these nucleating agents have the above-described effects, they have a relatively low molecular weight, and have problems such as stains on a mold during molding, odor and bleed-out in molded products due to their structures. On the other hand, as a method for solving these problems, there is a method using a compound having a relatively high molecular weight as a nucleating agent. For example, JP-A-1-242646 discloses that an ethylene polymer containing a highly crystalline 3-methyl-1-butene polymer has a high crystallization rate and solves the above problem as a nucleating agent. It is described that an improvement effect can be obtained.

[Problems to be solved by the invention]

JP-A-1-242646 describes various catalysts as Ziegler-Natta catalysts which give 3-methyl-1-butene polymers having a particularly high stereoregularity. 3-methyl-1-
Butene polymers are not particularly highly crystalline,
In addition, a masterbatch containing a 3-methyl-1-butene polymer is produced from a propylene polymer, and the resulting ethylene polymer composition has a reduced dispersibility in the ethylene polymer. In spite of the fact that the content of -methyl-1-butene was as high as 0.6% by weight, the crystallization temperature was slightly 4.4 times lower than that of the comparative example containing no 3-methyl-1-butene polymer. Only the temperature has risen. Therefore,
The effect of a nucleating agent generally required is insufficient, and at present, there is no complete method of using a compound having a relatively high molecular weight as a nucleating agent.

[Means for solving the problem]

In view of the present situation, the present inventors have conducted intensive studies to provide a nucleating agent using the above relatively high molecular weight compound,
When an ethylene copolymer containing 3-methyl-1-butene obtained by polymerization in the presence of a catalyst using a specific silicon compound is used, the content of 3-methyl-1-butene in the composition is low. Nevertheless, they have found that the above-mentioned nucleating agent effect is effectively exerted, and have completed the present invention.

That is, the present invention relates to the following (A) and (B) components: (A) linear polyethylene which is a copolymer of ethylene alone or a main component of ethylene and an α-olefin having 3 to 12 carbon atoms; (B) a solid titanium catalyst component containing halogen-containing magnesium, halogen-containing titanium and an electron-donating compound as essential components, an organoaluminum compound, and a general formula R ¹ R ² _3- nSi (OR ³ ) _n (where R ¹ is a branched hydrocarbon group; R ² and R ³ are each a branched or straight hydrocarbon group;
≦ n ≦ 3) 3-methyl-1-butene weight obtained by prepolymerizing 3-methyl-1-butene in the presence of a catalyst formed from an organosilicon compound represented by the formula: An ethylene copolymer having a combined content of 0.001 to 10% by weight and a melt flow rate equal to or higher than the melt flow rate of the component (A), and a 3-methyl-1-butene polymer content of 0.0001.
To 1% by weight of an ethylene polymer composition.

(A) Linear polyethylene In the present invention, the linear polyethylene of the component (A), which is blended with an ethylene copolymer containing 3-methyl-1-butene, comprises ethylene alone in the presence of a transition metal catalyst. Or ethylene and α- having 1 to 12 carbon atoms
It is obtained by copolymerizing with an olefin.

There are no particular restrictions on the catalyst and the polymerization method used in the production of the component (A). Examples of the catalyst include a Ziegler type catalyst, a Phillips type catalyst, and a Kaminski type catalyst. Slurry method, gas-phase fluidized bed method (for example, the method described in JP-A-59-23011), solution method, or high-pressure bulk polymerization method at a pressure of 200 kg / cm ² or more and a polymerization temperature of 150 ° C. or more. No.

The α-olefin used as a conomomer is a 1-olefin having 3 to 12 carbon atoms (R-CH = CH ₂ as a general formula).
And R represents an alkyl group), for example, propylene, butene-1, pentene-1, hexene-1,4-
Methylpentene-1,4-methylhexene-1,4,4-
Dimethylpentene-1, heptene-1, octene-1,
Nonene-1, decene-1 and the like, and preferably propylene, butene-1, hexene-1, 4-methylpentene-
1. Octin-1. The above α- as a comonomer
The olefin is not limited to one kind, but is
Preference is also given to multi-component copolymers of more than one type.

The component (A) of the present invention particularly has a density of 0.940 g.
Linear low-density polyethylene having a density of not more than / cm ³ is preferred.

(B) 3-methyl-1-butene-containing ethylene polymer 3-methyl-1 used as component (B) in the present invention
The ethylene copolymer containing -butene is produced by a method in which 3-methyl-1-butene is polymerized in advance using an ethylene polymerization catalyst, and then ethylene is polymerized.

The polymerization catalyst used for the polymerization of 3-methyl-1-butene is formed from a solid titanium catalyst component containing magnesium halide, titanium halide and an electron donating compound as essential components, and an organoaluminum compound and an organosilicon compound. A method using a catalyst to be used is preferred.

(Solid titanium catalyst component) Ethylene-3-methyl-1- as the component (B)
As the halogen-containing magnesium used for the solid titanium catalyst component used for producing the butene polymer or the ethylene copolymer, a dihalide is preferable, and magnesium chloride, magnesium bromide, and magnesium iodide can be used. Particularly preferred is magnesium chloride, and further desirably substantially anhydrous. The halogen-containing magnesium may be an electron-donating compound such as magnesium oxide, magnesium hydroxide, hydrotalcite, a carboxylate of magnesium, alkoxymagnesium, allyloxymagnesium, alkoxymagnesium halide, allyloxymagnesium halide, or an organic magnesium compound. , Halosilane, alkoxysilane, silanol, aluminum compound, titanium halide compound, titanium tetraalkoxide, or the like, may be halogen-containing magnesium.

Representative examples of the halogen-containing titanium include halogen compounds of trivalent and tetravalent titanium. A preferred halogen compound of titanium is a compound represented by the general formula Ti (OR) _n X _4-n (where R is a hydrocarbon residue having 1 to 10 carbon atoms, and X is a halogen). It is a tetravalent titanium halide compound in which n = 0, 1 or 2. Specifically, TiCl
₄ , Ti (OBu) Cl ₃ , Ti (OBu) ₂ Cl _{2 and the} like, and particularly preferred are titanium tetrahalides such as TiCl ₄ and Ti (OBu) Cl _{3 and} monoalkoxytrihalides. It is a titanium compound.

The electron donating compound is usually used as a modifier of a Ziegler type catalyst, and any compound can be selected and used for the purpose of the present invention. Preferred electron-donating compounds for use as so-called "internal donors" in the present invention are esters of polyfunctional compounds selected from the group consisting of polycarboxylic acids, polyhydric alcohols and hydroxy-substituted carboxylic acids.

Preferable examples of the ester of the polyfunctional compound include aliphatic and aromatic polycarboxylic acid esters. Particularly preferred is that at least one of the ester groups has 2 carbon atoms.
It is a diester of dicarboxylic acid which is the above alkyl group. Specific examples of preferable dicarboxylic acid esters include esters of phthalic acid, maleic acid, substituted malonic acid, and the like and alcohols having 2 or more carbon atoms, and particularly preferred are phthalic acid and alcohols having 4 or more carbon atoms. Diester.

(Organic Aluminum Compound) The aluminum compound used in the production of the ethylene polymer which is the component (B) used in the present invention has a general formula of AlR ′ _n X _3-n (where R ′ has 1 to 12 carbon atoms). And X represents a halogen or an alkoxy group, and n is 0 <n ≦ 3. Such organoaluminum compounds are specifically, for example, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, triisohexylaluminum, trioctylaluminum, Diethylaluminum hydride, diisobutylaluminum hydride, diethylaluminum monochloride, ethylaluminum sesquichloride, diethylaluminum monoethoxide and the like. Of course, two or more of these organoaluminum compounds can be used in combination. When such a catalyst is not used, a highly crystalline polymer cannot be obtained, and the effects of the invention cannot be obtained.

(Organosilicon compound) As the organosilicon compound, an organosilicon compound represented by the following formula is used.

R ¹ R ² _3- nSi (OR ³ ) _n (where R ¹ is a branched hydrocarbon group, R ² and R ³ are each a branched or linear hydrocarbon group, and n is 2 ≦ n ≦ 3 It is preferable that R ¹ is branched from a carbon atom adjacent to a silicon atom. In this case, the branching group is preferably an alkyl group, a cycloalkyl group or an aryl group (for example, a phenyl group or a methyl-substituted phenyl group). More preferred R ¹ is a carbon atom adjacent to a silicon atom, that is, the carbon atom at the α-position is a secondary or tertiary carbon atom. In particular, those having a structure in which three alkyl groups emerge from a carbon atom bonded to a silicon atom are preferable. The carbon number of R ¹ is usually 3-20, preferably 4-10. R ² is usually a branched or straight-chain aliphatic hydrocarbon group having 1 to 20, preferably 4 to 10 carbon atoms.
R ³ is usually an aliphatic hydrocarbon group, preferably an aliphatic hydrocarbon group having 1 to 4 carbon atoms.

(Polymerization) The polymerization method of the ethylene copolymer as the component (B) is as follows.
Generally, 3-dimethyl-
A preferred method is to polymerize 1-butene and subsequently polymerize ethylene.

The 3-methyl-1-butene-containing ethylene polymer as the component (B) has a 3-methyl-1-butene content of 0.00.
Those having 1 to 10% by weight and a melt flow rate equal to or higher than the melt flow rate of the component (A) are used in the present invention.

If the content of 3-methyl-1-butene is too small, the effect of the present invention is not exerted. If the content is too large, dispersibility in the component (A) deteriorates, which is not preferable.

Further, if the melt flow rate is lower than the melt flow rate of the component (A), the dispersibility in the component (A) is undesirably deteriorated.

(Composition) The mixing ratio of the component (B) is such that the content of 3-methyl-1-butene in the composition of the present invention is 0.0001 to 1% by weight, preferably
It may be determined so as to be 0.001 to 0.1% by weight. When the content of 3-methyl-1-butene is below this range, the nucleating agent effect, which is the object of the present invention, is insufficient. On the other hand, when the content exceeds this range, no further improvement effect is expected and economically. Disadvantageous.

Resin composition of the present invention, depending on the purpose and application other than the following components, various components conventionally used in this field, such as antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, crosslinking agents, Blowing agents, colorants, dispersants, fillers, antistatic agents, pigments, other nucleating agents, and the like can be added. The compounding method for producing the resin composition of the present invention is not particularly limited, and a known method can be used.

That is, after mixing the above components in a predetermined amount and passing through a commonly used mixer such as a Henschel mixer or a super mixer, a single screw kneader, a continuous melt kneading method using a twin screw kneader such as FMC or CIM, a roll or a banbury, etc. Is generally used. At the time of molding the composition of the present invention thus obtained, a molding temperature lower than the melting point of the 3-methyl-1-butene polymer contained in the conventionally known molding method, preferably at a lower molding temperature, Can be adopted. For example, typically, any of injection molding, hollow molding, extrusion molding, film molding, sheet molding, and rotational molding can be employed.

〔Example〕

Hereinafter, the resin composition of the present invention will be specifically described with reference to examples. However, the present invention is not limited to these embodiments without departing from the gist thereof.

In addition, the measuring method or definition of the physical property value shown in the Example is as follows.

(1) Melt flow rate (MFR): Conforms to JIS K6760.

(2) Density: According to JIS K6760 (density gradient tube method).

(3) Melting point and crystallization temperature: Measured by the DSC method as follows.

A 5 mg sample was taken out from a 1 mm thick sheet pressed at 160 ° C., set in a DSC device (manufactured by Perkin Elmer), heated to 160 ° C., and kept at this temperature for about 3 minutes. Cool down to 30 ° C at a rate of ℃ / min,
The onset temperature of the exothermic peak appearing during this crystallization was defined as the crystallization temperature.

Next, the temperature was raised from this state to 160 ° C. at a rate of 10 ° C./min, and the end temperature of the largest endothermic peak accompanying melting that appeared during this time was taken as the melting point.

(Production Example of 3-Methyl-1-butene-Containing Ethylene Polymer) Production Example 1 Preparation of Solid Catalyst Component A 500-ml glass three-necked flask equipped with a thermometer and a stirring bar was purged with nitrogen, and then 75 ml of a solid catalyst component was prepared. Purified heptane,
75 ml of titanium tetrabutoxide and 10 g of anhydrous magnesium chloride were added. The temperature of the flask was raised to 90 ° C., and magnesium chloride was completely dissolved over 2 hours. Next, the flask was cooled to 40 ° C., and 15 ml of methyl hydrogen polysiloxane was added to precipitate a magnesium chloride / titanium tetrabutoxide complex. After washing with purified heptane, 8.7 ml of silicon tetrachloride and 2.0 g of phthaloyl chloride were added, and the mixture was kept at 50 ° C. for 2 hours. Thereafter, the resultant was washed with purified heptane, 25 ml of titanium tetrachloride was further added, and the mixture was kept at 25 ° C. for 2 hours. This was washed with purified heptane to obtain a solid catalyst component. The titanium content in the solid catalyst component was 2.7% by weight.

3-Methyl-1-butene polymerization 500 ml purified heptane, 0.8 g solid catalyst component prepared above, 32 g 3
-Methyl-1-butene, 2 g of triisobutylaluminum and 0.6 g of tert-butylmethyldimethoxysilane were introduced and reacted at 50 ° C. for 3 hours. Thereafter, it was washed with purified heptane to remove unreacted portions.

The polymerization amount of 3-methyl-1-butene is per 1 g of the solid catalyst.
It was 25 g. The melting point of the polymer of 3-methyl-1-butene was 360 ° C.

Ethylene polymerization After sufficiently replacing the stirred autoclave having an internal volume of 3 with ethylene, sufficiently dehydrated n-heptane 1.5 was introduced, the temperature was maintained at 75 ° C, and the pressure was further increased to 7 kg / cm ^{2 with} ethylene. Then 0.38 g of triethylaluminum, 0.16 g of tert-butylmethyldimethoxysilane and the above 3-methyl-
780 g of 1-butene polymerized catalyst component (including 30 mg of solid catalyst component) was introduced, and polymerization was carried out at 75 ° C. for 3 hours while adjusting the hydrogen concentration in the gas phase to 45% by volume. Thereafter, ethylene was purged, and the polymerization was stopped by adding 10 ml of butanol, followed by filtration and drying to obtain 150 g of an ethylene copolymer powder.

This ethylene copolymer powder contained 5000 ppm of 3-methyl-1-butene, and had a melt flow rate of 50 g / 10 minutes. This was used as the component (B-1) for securing the required sample amount and used in the following experiments.

Production Example 2 Preparation of solid catalyst component Prepared in the same manner as in Production Example 1.

3-Methyl-1-butene polymerization Polymerization was carried out in the same manner as in Production Example except that tert-butylmethyldimethoxysilane was not used.

The polymerization amount of 3-methyl-1-butene is per 1 g of the solid catalyst.
It was 25 g. The melting point of the polymer of 3-methyl-1-butene was 298 ° C.

Ethylene Polymerization Polymerization was carried out in the same manner as in Production Example 1 except that tert-butylmethyldimethoxysilane was not used, and 143 g of an ethylene polymer powder was obtained. This ethylene copolymer powder contains 5200 ppm of 3-methyl-1-butene,
The melt flow rate was 58 g / 10 minutes. This is (B-
2) A necessary sample amount was secured as a component and used for the following experiments.

Production Example 3 Preparation of solid catalyst component Prepared in the same manner as in Production Example 1.

Ethylene polymerization The polymerization was carried out in the same manner as in Production Example 1 except that the 3-methyl-1-butene polymer was not contained, and 155 g of an ethylene copolymer powder was obtained.

The melt flow rate was 51 g / 10 minutes. This is (B
-3) A necessary sample amount was secured as a component and used in the following experiments.

(Production and Experiment of Ethylene Polymer Composition) Example 1, Comparative Examples 1-2 Melt flow obtained by a gas-phase polymerization process in the presence of a Ziegler-type catalyst as a linear polyethylene as the component (A). A linear low-density polyethylene granule (A-1) having a rate of 16 g / 10 minutes, a density of 0.921 g / cm ³ and a butene-1 copolymer component of 9.5% by weight was used.

In the above (A-1), the components (B) to (B-1)
(B-3) was added at the ratio shown in Table 1 and mixed with a Henschel mixer for 3 minutes, and then each was pelletized with a single-axis granulator, and these pellets were collected by Toshiba Machine Co., Ltd.
In-line screw injection molding machine "IS90B" and the first
Using the test piece and sheet mold shown in the figure, the cavity pressure detected from the strain gauge type load cell attached via the ejector pin of the mold is used for the injection molding measurement system "Mopack" manufactured by Nireco Co., Ltd.
220 ".

Here, the molten resin is filled into the cavity without changing the conditions of injection pressure setting 500 kg / cm ² , cylinder temperature setting 170 ° C., mold cooling water temperature 40 ° C., and with the speed of pressure decrease caused by crystallization solidification afterwards , Gate sealability or a guideline for the molding cycle. Time t ₅₀ from the time that specifically showing the maximum pressure to complete the filling until the pressure half (seconds)
Was compared. FIG. 2 schematically shows these measured values.

At the same time, the respective crystallization temperatures were also measured by the DSC method.

Further, an injection molded sheet having a thickness of 100 mm × 100 mm × 1 mm was obtained, and the transparency was measured by a haze meter and the gloss was measured by a gloss meter.

The transparency was also measured on a 1 mm thick compression molded sheet obtained at 160 ° C.

On the other hand, a compression molded sheet having a thickness of 2 mm was obtained at 160 ° C., and the bending rigidity was measured in accordance with ASTM D747.

 Table 1 shows the results.

Example 2, Comparative Examples 3 and 4 As the linear polyethylene as the component (A), a melt flow rate of 2.0 g / 10 min, a density of 0.921 g / obtained by a gas phase polymerization process in the presence of a Ziegler catalyst. cm3,
A linear low-density polyethylene granule (A-2) having a butene-1 content of 7.5% by weight as a copolymer component was used.

In the above (A-2), the components (B) to (B-1)
(B-3) was added at the ratio shown in Table 2, mixed with a Henschel mixer for 3 minutes, and each was pelletized with a single-axis granulator, and the pellets were “IPB10A” manufactured by Ishikawajima-Harima Heavy Industries, Ltd. (Screw diameter 40mmφ, die lip width 1.5m
m) at a molding temperature of 170 ° C and a cylindrical hollow bottle (internal volume 80
0 cc and a meat pressure of 0.5 mm).

Cut out the side from this cylindrical hollow bottle, JIS K7105
The transparency was measured in accordance with. The transparency was also measured for a 1 mm thick compression molded sheet obtained at 160 ° C. Further, at a molding temperature of 240 ° C., a bottle was molded in the same manner, and immediately after molding, the smell inside the bottle was smelled to determine the presence or absence of odor. Table 2 shows the results.

Example 3, Comparative Examples 5 to 6 As a linear polyethylene as the component (A), a melt flow rate of 1.0 g / 10 minutes and a density of 0.920 g / obtained by a gas phase polymerization process in the presence of a Ziegler-type catalyst. cm ³ ,
A linear low-density polyethylene granule (A-3) having a butene-1 content of 8.1% by weight as a copolymer component was used.

The component (B) is added to the component (A-3) as the component (B).
(B-3) was added at the ratio shown in Table 3, mixed for 3 minutes with a Henschel mixer, and then pelletized with a single-axis granulator, and these pellets were 40 mmφ manufactured by Tommy Machine Industry Co., Ltd.
Die temperature 20 by blown film molding machine
A film having a thickness of 30 μm was obtained at 0 ° C.

The transparency of this film was measured with a haze meter, and the gloss was measured with a gloss meter. Table 3 shows the results.

[Effect of the Invention] The ethylene polymer composition of the present invention is obtained by using an ethylene polymer containing 3-methyl-1-butene obtained by polymerizing in the presence of a specific catalyst, so that 3 The nucleating agent effect can be effectively obtained despite the extremely low content of -methyl-1-butene.

According to the composition of the present invention, the molding cycle can be shortened by improving the transparency, gloss and rigidity of the molded article and the crystallization speed, and the mold can be stained during molding, and the odor and bleeding of the molded article can be achieved. There is no problem such as out.

[Brief description of the drawings]

FIG. 1 is a side view and a top view showing a test piece and a sheet formed by injection molding. FIG. 2 is an explanatory diagram schematically showing a change in cavity pressure in injection molding.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryoichi Kitani 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Yuka Co., Ltd. In Yokkaichi Research Institute (56) References JP-A 1-311106 (JP, A) 1-229007 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 23/02-23/24 C08F 4/60-4/70

Claims (1)

(57) [Claims] 1. A composition comprising the following components (A) and (B):
An ethylene polymer composition having a methyl-1-butene polymer content of 0.0001 to 1% by weight. (A) Linear polyethylene which is a copolymer of ethylene alone or a main component of ethylene and an α-olefin having 3 to 12 carbon atoms. (B) a solid titanium catalyst component containing halogen-containing magnesium, halogen-containing titanium and an electron-donating compound as essential components, an organic aluminum compound, and a general formula R ¹ R ² _3- nSi (OR ³ ) _n (where R ¹ is a branched hydrocarbon group; R ² and R ³ are each a branched or straight hydrocarbon group;
≦ n ≦ 3) 3-methyl-1-butene obtained by prepolymerizing 3-methyl-1-butene in the presence of a catalyst formed from an organosilicon compound represented by the formula: An ethylene copolymer having a polymer content of 0.001 to 10% by weight and a melt flow rate equal to or higher than the melt flow rate of the component (A).