JPH0354124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a propylene-ethylene random copolymer having excellent properties. Crystalline propylene/ethylene random copolymers containing a small proportion of ethylene are widely used and processed into various films, hollow bodies, injection molded products, and the like. In particular, in the film field, it is widely used as a variety of packaging materials because it has better heat sealability than propylene homopolymer. However, the propylene/ethylene random copolymers conventionally provided cannot necessarily be said to have sufficiently high impact strength. In addition, if we try to obtain a fluoropylene/ethylene random copolymer with high ethylene content and relatively low melting point and excellent heat sealability, it will become sticky and result in a product with poor commercial value.
A propylene/ethylene random copolymer with an ethylene content exceeding 5 mol % is not commercially available. As a result of various studies to obtain a random copolymer with even better properties, the inventors of the present invention found that compared to propylene/ethylene random copolymers that have the same ethylene content or the same melting point and have been used in practical use in the past. Transparency, heat sealability,
We have now discovered a random copolymer that has excellent physical properties such as stiffness, tensile strength, and improved impact strength. Therefore, the object of the present invention is to provide a material with excellent transparency, heat sealability, impact resistance, rigidity, tensile strength, etc.
An object of the present invention is to provide a novel propylene/ethylene random copolymer that exhibits less stickiness and stickiness when formed into a film. Another object of the present invention is to provide a propylene/ethylene random copolymer having good powder flowability, from which it has been difficult to obtain a polymer powder with good flowability. According to the present invention, (A) the total ethylene content is 3 to 12
mol%, (B) isolated ethylene content (E mol%)
2.0 to 10.0 mol%, (C) the amount of decane soluble portion (D weight %) is (0.6E + 2.0) to (0.6E + 6.0) weight %, (D) the intrinsic viscosity measured at 135°C in decalin [ A propylene/ethylene random copolymer having an intrinsic viscosity [η] D of 1.0 to 4.0 dl/g and (E) an intrinsic viscosity [η] _D of the decane-soluble portion measured at 135°C in decalin of 0.5 to 3.0 dl/g. is provided. The total ethylene content of the copolymer of the present invention is from 3 to 12
mol %, preferably 4 to 10 mol %. When the ethylene content is less than 3 mol%, the propylene random copolymer becomes inferior in transparency, heat sealability, and impact resistance; This results in poor sealing properties and impact resistance, and hollow molded bodies and injection molded bodies molded from the copolymer have poor transparency and impact resistance. In addition, the ethylene content is 12 mol%
If the propylene random copolymer exceeds Hollow molded bodies and injection molded bodies molded from such materials have poor heat resistance and rigidity. The total ethylene content is the value determined by C ¹³ NMR. Further, the isolated ethylene content (E mol%) of the copolymer of the present invention is 2.0 to 2.0.
The content is 10.0 mol%, particularly preferably in the range of 3.0 to 7.0 mol%. This typically results in a melting point (measured by differential scanning calorimetry) of the copolymer ranging from about 150° to about
It can vary in the range of 130°C. If the isolated ethylene content of the propylene random copolymer is less than the above range, the propylene random copolymer will have poor transparency, heat sealability and impact resistance, even if molded from the propylene random copolymer. The resulting film becomes inferior in transparency, heat sealability, and impact resistance, and the blow molded article and injection molded article formed from the copolymer are inferior in transparency and impact resistance. Furthermore, if the isolated ethylene content of the propylene random copolymer exceeds the above range, the heat resistance, rigidity, and blocking resistance will be poor, and for example, hollow molded articles molded from the propylene random copolymer and The injection molded product becomes inferior in heat resistance and rigidity. In the present invention, the isolated ethylene content is a value determined by C ¹³ NMR. The copolymers of the present invention can also be prepared at 135°C in decalin.
The intrinsic viscosity [η] measured at is 1.0 to 4.0 dl/
g, preferably in the range of 1.5 to 3.5 dl/g, and within this range, films, blow molded articles and blow molded articles formed from the propylene random copolymer exhibit excellent mechanical properties, If it is smaller than this value, mechanical properties cannot be obtained, and if it exceeds this value, moldability becomes poor. The copolymer of the present invention has an isolated ethylene content of E
When expressed as mol%, the amount of n-decane soluble portion (D weight%) is (0.6E+2.0) to (0.6E+6.0) weight%,
It is preferably in the range of (0.6E+2.5) to (0.6E+4.0)% by weight, and the intrinsic viscosity [η] _D measured at 135°C of the n-decane soluble portion in decalin is 0.5 to 3.0 dl/ g, preferably 0.8 to 2.5 dl/g. As mentioned above, the n-decane soluble portion is slightly larger than that of similar commercially available random copolymers, and because the intrinsic viscosity of the decane soluble portion is within the above range, the impact strength is improved. It is strong and has little stickiness even though it has a relatively high content of isolated ethylene, so it can be suitably used for molded products such as films. Even if the content of the n-decane soluble portion in the propylene random copolymer exceeds the above range, or even if the intrinsic viscosity of the n-decane soluble portion of the polymer is smaller than the above range, the copolymer When combined, heat resistance and rigidity become inferior, the surface becomes more sticky, and blocking resistance becomes inferior. Therefore, films molded from the propylene random copolymer have poor heat resistance and blocking resistance, and the surface becomes more sticky, and blow molded and injection molded products have poor heat resistance and blocking resistance. Rigidity becomes inferior. Further, even if the content of the n-decane soluble portion in the propylene random copolymer is smaller than the above range, or even if the intrinsic viscosity of the polymer of the n-decane soluble portion exceeds the above range, The copolymer becomes poor in impact resistance and heat sealability. Therefore, films formed from the propylene random copolymer have poor impact resistance and heat sealability, and blow molded articles and injection molded articles have poor impact resistance. Here, the n-decane soluble portion is calculated by adding 10 g of random copolymer to 1
After uniformly dissolving in n-decane by heating at 140°C for 2 hours, the precipitated solid part was left to cool overnight in a constant temperature bath at 23°C, and the precipitated solid part was obtained by over-separation at 23°C. The ratio can be determined by heating the n-decane solution under reduced pressure to remove the n-decane solvent and weighing the residue. In the present invention, the above characteristics (A) ~
It is possible to provide a propylene/ethylene random copolymer which is equipped with (E) and has extremely excellent fluidity. That is, (F) powder flowability index is 80 or more,
A copolymer powder preferably exhibiting a value of 90 or more can be provided. Such copolymer powders usually have a regular shape and are particularly low in stickiness. Because the above copolymer powder has good fluidity, when manufactured by slurry polymerization, it has the advantage that it is easy to dry and can be dried stably without any trouble, and it is also easy to handle and mold. Moreover, since powder molding is easy, if desired, it is possible to omit the usual pelletization and mold the powder into a final product as it is. Note that the powder fluidity index (F) here is a value measured using a powder tester manufactured by Hosokawa Powder Engineering Research Institute. The propylene/ethylene random copolymer of the present invention can be advantageously produced by the following method. For example, () magnesium, titanium,
It is formed from a highly active titanium catalyst component containing as essential components an ester of chlorine and phthalic acid with an alcohol having 2 or more carbon atoms, () trialkyl aluminum and () an organosilicon compound catalyst component having a Si-O-C bond. It can be produced by copolymerizing propylene and ethylene at a temperature of about 20°C to about 100°C using a catalyst. The component () contains amorphous magnesium chloride, and preferably has a specific surface area of about 40 to about
800 m ² /g, with a chlorine/titanium (atomic ratio) of about 5 to about 100, a phthalate/titanium (molar ratio) of about 0.2 to about 6, and a magnesium/titanium (molar ratio) of about 4 to about 50 and may contain other electron donors, functional groups, metals, elements, etc. The titanium catalyst component (A) preferably has a granular, regular shape with a particle size of about 1 to about 100 microns, and preferably has a narrow particle size distribution. In order to obtain a copolymer powder with particularly excellent powder fluidity, as such a titanium catalyst component, for example, JP-A-55-135102, JP-A-55-135103, JP-A-56-
811, Japanese Patent Application No. 56-181019, etc. can be used. Examples of esters of phthalic acid, which are essential components in the titanium catalyst component (), include diethyl phthalate, di-n-propyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, and di-n-hexyl phthalate. , n-octyl phthalate, 2-ethylhexyl phthalate, ethyl n-octyl phthalate, and the like. Trialkylaluminium () is, for example, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trin-
Hexylaluminum, tri-n-butylaluminum, etc. Representative examples of organosilicon compounds () include methyltrimethoxysilane, phenylmethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, vinyltributoxysilane, ethyl silicate, These include diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane. When producing the random copolymer, polymerization can be carried out in either a liquid phase or a gas phase. When carrying out liquid phase polymerization, an inert solvent such as hexane, heptane or kerosene may be used as the reaction medium, but propylene itself may also be used as the reaction medium. The amount of catalyst used is approximately 0.0001 titanium atoms per reaction volume.
to about 1.0 mmol, component () so that the amount of metal atoms in component () is about 1 to about 2,000 moles, preferably about 5 to about 500 moles, per 1 mole of titanium atoms in component (); () ingredients,
The amount of Si atoms in component () is about 0.001 to about 10 mol, preferably about 0.01 to about 2 mol, particularly preferably about 0.04 mol per mol of metal atom in component ().
Preferably, the amount is from about 1 mole to about 1 mole. These catalyst components (), (), and () may be brought into contact with each other during polymerization, or may be brought into contact with each other before polymerization. In this contacting before polymerization, only two arbitrary components may be freely selected and brought into contact, or a part of each component may be brought into contact with two or three components. Furthermore, each component may be brought into contact with each other before polymerization under an inert gas atmosphere or under an olefin atmosphere such as propylene. The copolymerization temperature is preferably about 20 to about 100
C., more preferably about 50 to about 80.degree. C., and the pressure is preferably normal pressure to about 50 kg/ ^cm.sup.2 , preferably about 2 to about 50 kg/ ^cm.sup.2 . The copolymerization is preferably carried out continuously. The limiting viscosity can also be adjusted advantageously by using hydrogen. Copolymerization can also be carried out in two or more polymerization stages with different reaction conditions. Example 1 [Preparation of highly active titanium catalyst component] 2.38 kg of anhydrous magnesium chloride, 12.5 kg of decane and 3.26 kg of 2-ethylhexyl alcohol were added to 130 kg of
After heating the reaction at ℃ for 2 hours to make a homogeneous solution, 0.56 kg of phthalic anhydride was added to this solution and heated at 130℃.
The mixture was further stirred and mixed for 1 hour to dissolve phthalic anhydride into the homogeneous solution. After the homogeneous solution thus obtained was cooled to room temperature, the entire amount was dropped into titanium tetrachloride 100 maintained at -20°C over 1 hour. After charging, the temperature of this mixed liquid was increased to 4.
The temperature was raised to 110°C over a period of time, and when it reached 110°C, 1.75 kg of diisobutyl phthalate was added, and the mixture was maintained at the same temperature for 2 hours with stirring. After 2 hours of reaction, the solid part was collected by heating, and this solid part was resuspended in 100% TiCl4, and then again suspended in 110% _TiCl4 .
The heating reaction is carried out for 2 hours at °C. After the reaction is completed, the solid portion is collected again by heating and thoroughly washed with decane and hexane at 110°C until no free titanium compound is detected in the washing liquid. The solid Ti catalyst component [A] synthesized by the above production method is stored as a hexane slurry, and a portion of it is dried for the purpose of examining the catalyst composition. The composition of the highly active titanium catalyst component [A] obtained in this way is titanium
2.8wt%, chlorine 55.0wt%, magnesium 18.0wt
% and diisobutyl phthalate 14.3% by weight. [Manufacture of propylene/ethylene random copolymer] [] Pretreatment of catalyst After charging purified hexane 50% to a 100% reactor purged with nitrogen, triethylaluminum
7.5mol, diphenyldimethoxysilane 1.5mol
and highly active titanium catalyst components in terms of titanium atoms.
After charging 0.75 mol, propylene was fed at a feed rate of 600/hour over 4 hours to polymerize 2.7 g of propylene per 1 g of the highly active titanium catalyst component. [] Production of propylene/ethylene random copolymer Using a polymerization system consisting of two 100 polymerization pots,
A copolymer was produced. The various catalyst components were fed only to the first stage. The feed ratios of the various catalyst components were such that the triethylaluminum/diphenyldimethoxysilane ratio was 10 (molar ratio) and the triethylaluminum/titanium atomic ratio in the highly active titanium catalyst component was 80 (molar ratio). The polymerization temperature was 60℃ in both reaction vessels, and the polymerization pressure was 7Kg/cm ²
G (first stage) was 5 Kg/cm ² G (second stage), and the residence time was 3 hours in both reaction vessels. The feed amount of propylene and ethylene is 4.1 kg/hour of propylene in the first stage as the first level.
1.9Kg/hour of propylene in the second stage, 0.12Kg/hour of ethylene in the first stage, 0.14Kg/hour of ethylene in the second stage
Kg/hour. In addition, as a second level, the propylene in the first stage is 4.1Kg/hour, and the propylene in the second stage is 1.0Kg/hour.
Kg/hour, ethylene in the first stage was 0.18Kg/hour, and ethylene in the second stage was 0.12Kg/hour. Table 1 shows the physical properties of the obtained polymer powder. The fluidity index of the obtained polymer powder was 96 at the first level and 93 at the second level. [Film Formation] Using a Modern Machinery 40m/m film forming machine, a 20μ thick film was drawn at a resin temperature of 230°C and water-cooled. A cast film with a thickness of 20μ was drawn using a Mitsubishi 65mm T die at a resin temperature of 260°C. A film with a thickness of 20 μm was drawn using a Modern Machinery 50 mm film forming machine at a resin temperature of 230°C and air cooling. Table 1 shows the impact strength of various films. Comparative Examples 1 and 2 Propylene-ethylene copolymerization was carried out at 50° C. using hexane as a solvent using a catalyst system consisting of titanium trichloride and diethylaluminum monochloride. By changing the feed ratio of propylene and ethylene, polymer powders with an isolated ethylene content of 3.2 mol% and a polymer powder with an isolated ethylene content of 4.4 mol% were obtained. Each of these liquidity indices is
They were 79 and 65. The results are shown in Table-1. Comparative Example 3 In Level-1 of Example 1, the triethylaluminum/diphenyldimethoxysilane ratio was 10
Propylene-ethylene copolymerization was carried out in the same manner except that the molar ratio was changed from (molar ratio) to 150 (molar ratio). The results are shown in Table-1. Comparative Example 4 Furthermore, in Level-1 of Example 1, the same procedure was carried out except that the ethylene supply amount in the first stage was 0.05 Kg/hour, and the ethylene supply amount in the second stage was 0.06 Kg/hour.
Propylene-ethylene copolymerization was carried out. The results are shown in Table-1. 【table】

Claims (1)

[Scope of Claims] 1 (A) Total ethylene content of 3 to 12 mol%, (B) Isolated ethylene content (E mol%) of 2.0 to 10.0 mol%, (C) Amount of n-decane soluble portion (D weight%) is (0.6E+
2.0) to (0.6E+6.0)% by weight, (D) Intrinsic viscosity measured at 135°C in decalin [η]
is 1.0 to 4.0 dl/g, and (E) has an intrinsic viscosity [η]D of 0.5 to 3.0 dl/g as measured at 135°C in decalin of the decane-soluble portion. Random copolymer. 2. (F) The copolymer according to claim 1, which has a powder fluidity index of 80 or more.