JPH0518863B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a propylene copolymer composition. More specifically, (A) the first step is the homopolymerization of propylene, the second step is the copolymerization of propylene and ethylene, which is a block copolymer of propylene and ethylene, and (B) the low density ethylene and α-olefin. An object of the present invention is to provide a propylene copolymer composition having excellent impact resistance and transparency. [Prior Art] The generally widely used "propylene homopolymer" (hereinafter referred to as "PP") does not necessarily have satisfactory impact resistance, and many attempts to improve it have been proposed. For example, a block copolymer obtained by block copolymerizing propylene and a small amount of ethylene is a typical example, and the impact resistance is greatly improved. However, simply using a block copolymer has disadvantages such as poor transparency and also causing a whitening phenomenon upon impact. Another method is to resin-blend a high-density ethylene polymer with PP, but the resulting composition not only has poor transparency but also poor compatibility between the two, resulting in a decrease in tensile elongation. Furthermore, in the proposed method of blending PP with a low-density ethylene polymer obtained by a so-called high-pressure method, the transparency of the resulting composition is quite good, but the effect of improving impact resistance is not sufficient. Not only that, but the tensile elongation also decreases. In addition, ethylene-propylene copolymer rubber (EPR), ethylene-propylene-diene ternary copolymer rubber (EPDM) and ethylene-butene-
A method of compounding a rubber-like material such as 1-copolymer rubber has also been proposed, but this method improves impact resistance,
Although tensile elongation and transparency are improved,
There is a severe decrease in rigidity, a decrease in heat resistance, and a large amount of solvent extraction, which poses food hygiene problems. Furthermore, since these rubber-like materials are generally supplied in the form of lumps or pellets, they tend to stick to each other during resin blending such as melt-kneading, resulting in problems such as poor workmanship. [Means for Solving the Problems] Based on the above, the present inventors have obtained a propylene-based polymer composition that does not have these problems and has an excellent balance in rigidity, impact resistance, and transparency. As a result of various studies, we found that (A) Propylene was polymerized alone in the first step, and then propylene and ethylene were copolymerized in the second step to achieve a melt flow rate (JIS K-7210 Table 1-Condition 14). According to the method, the propylene-ethylene block copolymer (hereinafter referred to as "block copolymer") was measured at a temperature of 230 DEG C. and a load of 2.16 kg, and the propylene-ethylene block copolymer (hereinafter referred to as "MFI") was 0.3 to 50 g/10 minutes. ) 100 parts by weight and (B) Melt flow rate (JIS K-7210 Table 1-
Measured according to the method of Condition 4 at a temperature of 190°C and a load of 2.16 kg, hereinafter referred to as "MI". ) is 0.1-30g/10min, and the density is 0.910
~0.930g/cm ³ copolymer of ethylene and α-olefin (hereinafter referred to as “ethylene copolymer”)
That's what it means. ) It has been discovered that a propylene copolymer composition consisting of 5 to 30 parts by weight not only has good impact resistance and transparency, but also has improved the above-mentioned problems, and has developed the present invention. reached. Hereinafter, the configuration of the present invention will be explained in more detail. (A) Block copolymer The block copolymer that is the object of the present invention
MFI is 0.3-50g/10min. This block copolymer is produced by block copolymerization of propylene and ethylene using a catalyst system (so-called Ziegler-Natsuta catalyst) obtained from a solid catalyst component containing a transition metal and an organoaluminium compound or an electron-donating organic compound thereof. It is obtained by polymerization. The solid catalyst component is widely known in the polymerization of propylene, and includes carriers such as titanium trichloride or its eutectic, and magnesium compounds (which may or may not be treated with other compounds in advance). Typical examples include trivalent or tetravalent titanium compounds or those obtained by treating these compounds with other compounds. The block copolymerization method involves polymerizing propylene alone in the first step, and then copolymerizing propylene and ethylene in the second step. The amount is 1-20% by weight. (B) Ethylene copolymer Furthermore, the ethylene copolymer used in the present invention has an MI of 0.1 to 30 g/10 minutes.
In addition, the density is 0.910-0.930g/ ^cm3 , especially
0.915 to 0.925 g/cm ³ is desirable. The ethylene copolymer contains a solid catalyst component containing transition metals such as titanium, chromium, vanadium, and zirconium (including those in which compounds of these transition metals are supported on a carrier such as a magnesium compound) and an organic aluminum compound. It is obtained by copolymerizing ethylene and α-olefin using a catalyst system in combination with ethylene and α-olefin. The α-olefin is generally an α-olefin having 3 to 12 carbon atoms,
Among these, those having 3 to 10 carbon atoms are preferred.
Representative examples of preferred α-olefins include propylene, butene-1, hexene-1,4-methylpentene-1, octene-1 and decene-1.
can be mentioned. (C) Production of composition (1) Composition ratio In producing the composition of the present invention, 100%
The composition ratio of the ethylene copolymer to the weight parts of the block copolymer is 5 to 30 parts by weight. (2) Method for producing the composition The purpose of the present composition can be achieved by uniformly mixing a block copolymer and an ethylene copolymer to form a propylene copolymer composition. Examples of the mixing method include melt-kneading using mixers commonly used in this field, such as open rolls, kneaders, Banbury mixers, and extruders. In addition, a more uniform propylene copolymer composition can be obtained by preparing a mixture of the two in advance by a dry blending method and melt-kneading this mixture. (3) Additives The composition of the present invention can be obtained by uniformly mixing a block copolymer and an ethylene copolymer by the method described above, but depending on the purpose of use of the composition, it may be added to light (ultraviolet rays). ), heat, oxygen and ozone stabilizers, flame retardants, lubricants, fillers, antistatic agents and antiblocking agents, and the resulting compositions are also encompassed by the present invention. . Since the composition obtained in the present invention has the above-mentioned excellent effects, it can be made into a film shape by molding methods such as extrusion molding, blow molding, and injection molding, which are practiced in the field of PP.
It can be formed into sheets, rods, pipes, containers, etc. The molded products obtained in this way can be used in a wide variety of fields, but typical applications include parts for vehicles such as automobiles, parts for electrical appliances, parts for machines, containers, and other daily necessities. Examples include miscellaneous goods. [Examples and Comparative Examples] Hereinafter, implementation of the present invention will be specifically described using Examples. In addition, in Examples and Comparative Examples, Izod impact strength was measured at 0° C. according to ASTM D-256. Tensile elongation was measured according to JIS K-6758. In addition, the extract can
It is the proportion (percentage) of the extract extracted by treating 5 g of the pulverized material obtained by grinding with a mill for 6 hours using boiling n-hexane,
Stiffness is JIS K-6758-
For pressed pieces obtained according to 1968,
Measured according to ASTM D-747-63. Furthermore,
Haze is measured using a haze meter (manufactured by Suga Test Instruments Co., Ltd., product name HGM-2D).
Measurements were made using a 0.4 mm press piece. The various propylene and ethylene block copolymers and ethylene and α-olefin copolymers used in the Examples and Comparative Examples were prepared in advance by the following methods. (A) Production example of block copolymer 1 Titanium trichloride (manufactured by Toyo Stouffer Co., Ltd., AA
(type) and 5 g of tributylamine were ground in advance for 20 hours using a vibrating ball mill to prepare a titanium trichloride composition. 18.6 g of this titanium trichloride composition and 30.0 g of diethylaluminum chloride were charged into a 100-liter autoclave, and then 30 kg of propylene and hydrogen were introduced into the first autoclave so that the hydrogen concentration in the liquid layer was 1600 ppm (mol). Polymerization was carried out in stages for 60 minutes at a temperature of 70°C. Subsequently, in the second step, ethylene was added at this temperature and copolymerization of propylene and ethylene was carried out for 13 minutes while injecting ethylene under pressure so that the ethylene partial pressure became 4.5 Kg/cm ² (gauge pressure). and ethylene monomer were discharged from the system to terminate the polymerization. The obtained unpurified fluff was washed twice with n-butyl alcohol at a temperature of 90°C, and then thoroughly dried. As a result, 17.2g
A white powdery polymer was obtained. The ethylene content of this copolymer is 8.6% by weight, and the MFI is
It was 6.7g/10 minutes. (B) Production of ethylene copolymer Production examples 2 to 4 Solid obtained by placing 50 g of anhydrous magnesium chloride and 5.0 g of titanium tetrachloride in a vibrating ball mill with an internal volume of 1 and co-milling for 20 hours. 3 catalyst components (the amounts used are shown in Table 1) and 0.4 g of triisobutylaluminum each.
The isobutane and α-olefin (types and amounts used are shown in Table 1) were introduced into the autoclave. Ethylene was introduced so that the ethylene partial pressure was 3 Kg/cm ² (gauge pressure) at a temperature of 60°C, hydrogen was added (the hydrogen partial pressure is shown in Table 1), and ethylene and α-
Copolymerization with olefin was carried out. The polymerization was then terminated by discharging the contained gas to the outside of the system. Each of the obtained copolymers of ethylene and α-olefin
Drying was performed at 60°C under reduced pressure for 12 hours. The yield of each copolymer is shown in Table 1.

[Table] Example 1, Comparative Examples 1 to 3 100 parts by weight of block copolymer and 10 parts by weight of polymer (a) and 0.1% by weight of lauryl stearyl thiodipropionate and 0.1% by weight of tetrakis as stabilizers [Methylene-3-(3',5'-di-
A mixture was prepared by dry blending tertiary-butyl-4'-hydroxyphenyl)propionate]methane and 0.2% by weight of calcium stearate for 2 minutes using a Henschel mixer. The resulting mixture was kneaded at a temperature of 230° C. using an extruder (diameter 30 mm) to form pellets. The obtained pellets were press-molded for 5 minutes at a temperature of 230° C. under a pressure of 50 kg/cm ² to prepare test pieces. Instead of polymer (a) used in Example 1
An ethylene homopolymer obtained by a high-pressure method (hereinafter referred to as "polymer (d)") having an MI of 7.0 g/10 min and a density of 0.910 g/cm ³ (hereinafter referred to as "polymer (d)") and a MI of
A high-density ethylene polymer (hereinafter referred to as "polymer (e)") with a density of 10.0 g/10 minutes and a density of 0.965 g/cm ³ was used except that 10 parts by weight of each of Comparative Example (3) was used. Dry blending was carried out as in Example 1.
(Comparative Example 1 is a block copolymer alone.) Stiffness, haze, 0 of each test piece obtained in Example 1 and Comparative Examples 1 to 3
Izot impact strength (notched) at °C,
Measurements of MFI, tensile elongation and amount of extractables were made. The results are shown in Table 2. Examples 2 to 5 In place of the polymer (a) used in Example 1, 5 parts by weight of copolymer (b) was blended (Example 2), 10
Dry blending and kneading were performed in the same manner, except that parts by weight were blended (Example 3), 20 parts by weight was blended (Example 4), and 10 parts by weight of copolymer (c) was blended (Example 5). After the preparation, a test piece was prepared. The results are shown in Table 2.

[Table] From the results of the above Examples and Comparative Examples, the composition obtained by the present invention not only has excellent impact resistance and transparency, but also has good stiffness and tensile elongation, and has excellent performance. It is clear that the amount of extraction by solvent is small, and the processability is also excellent. [Effects of the Invention] The composition obtained by the present invention not only has good impact resistance and transparency at low to normal temperatures, but is also excellent in the following points. (1) High stiffness and tensile elongation, and improved whitening. (2) Since the amount extracted by solvent is small, it does not cause food hygiene problems. (3) Not only can the composition be produced without the occurrence of mutual adhesion as in the case of using the above-mentioned rubber-like material, but also the processability in producing molded products is good.

Claims (1)

[Claims] 1 (A) In the first step, propylene is polymerized alone, and then in the second step, propylene and ethylene are copolymerized so that the melt flow rate (230°C, 2.16 kg) is 0.3 to 50 g/10 minutes,
Block copolymer of propylene and ethylene with an ethylene content of 1 to 20% by weight 100
Part by weight and (B) Melt flow rate (190℃, 2.16Kg) is 0.1
〜30g/10min, and the density is 0.910~0.930g/
A propylene copolymer composition comprising ⁵ to 30 parts by weight of an ethylene copolymer of ethylene and α-olefin having a molecular weight of 5 to 30 parts by weight.