JPS6138927B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a propylene block copolymer composition having excellent low-temperature impact resistance and rigidity. Specifically, the present invention relates to a propylene block copolymer composition having a high melt flow index, excellent impact resistance, rigidity, and high elongation at break. Many studies have already been carried out on ways to solve the drawback of crystalline polypropylene being brittle at low temperatures. Among them, the method of copolymerizing propylene with olefin, especially ethylene, has been carried out on an industrial scale, and many products are already on the market. Supplied.
In particular, various methods using block copolymerization have been studied as preferred methods, and two-stage block copolymerization, three-stage block copolymerization, etc. are known (for example, JP-A No. 44-20621, JP-B No. 47-26190, Unexamined Japanese Patent Publication 1973
-45308, JP-A-142652, JP-A-55-
8011, JP-A-55-16048, JP-A-56-53118, etc.). On the other hand, there is a desire to shorten the cycle during molding or to reduce the amount of energy required, and in response, attempts are being made to improve flowability, but it is simply a matter of increasing the melt flow index. In other words, because it only lowers the molecular weight of the polymer, the impact resistance is greatly reduced, and it is said to have a large impact on the impact resistance of the molded product when it is actually made. The elongation at break (ASTMD638) is extremely small. Therefore, even if good results are obtained using the standard impact resistance testing methods such as Shapey impact strength (ASTMD256-56) and Dupont impact strength (JISK6718), if the elongation at break is small, the actual molded product may This results in poor impact resistance. Therefore, a copolymer with relatively high elongation is desired. As a result of various studies, the present inventors have discovered that a propylene block copolymer composition containing a specific copolymer in a specific ratio possesses the above-mentioned desirable physical properties, and has developed the present invention. completed. An object of the present invention is to provide a propylene block copolymer composition that has a relatively high melt flow index, high stiffness and impact resistance, and high elongation at break. That is, when the propylene block copolymer of the present invention is dissolved and separated with (A) a hydrocarbon having 6 to 20 carbon atoms, (1) it is soluble at 30°C;
60% by weight and 80-40% by weight of ethylene,
5 to 15 parts by weight of a copolymer portion A having an intrinsic viscosity (hereinafter simply referred to as intrinsic viscosity) ηA in a tetralin solution at 135°C of 2.0 to 7.0, (2) insoluble at 30°C and soluble at 110°C; , 5 to 30 parts by weight of a copolymer part B consisting of 90 to 70% by weight of propylene and 10 to 30% by weight of ethylene and having an intrinsic viscosity ηB of 0.4 to 3.0, and (3) insoluble at 30°C and 110°C However, it is insoluble, consists of 100-95% by weight of propylene and 0-5% by weight of ethylene, and has an intrinsic viscosity ηC of
The copolymer portion C is 60 to 90 parts by weight, and (B) ηA is larger than ηB and ηC. The composition of the present invention is completely dissolved in a hydrocarbon having 6 to 20 carbon atoms such as hexane, heptane, decane, etc., and the soluble portion (copolymer portion A) is separated when the temperature is lowered to 30°C. , further remove the insoluble part at 30℃
A soluble part (copolymer part B) extracted with the above hydrocarbons at 110°C and a part insoluble at 30°C and 110°C
Its characteristics can be clearly seen when it is divided into the above-mentioned hydrocarbon-insoluble portion (copolymer portion C), and the infrared absorption spectrum of each copolymer portion also has characteristics. That is, copolymer portion C is 997 cm ^-1 and 974 cm ^-1
The ratio of absorbance in the copolymer portion A is 0.8 to 0.995, which is a region with high stereoregularity, and the copolymer portion A has an absorbance ratio of 0.3 or less, which is a region with extremely low stereoregularity. In addition, the copolymer part B is 0.6~
0.9, which is a region with considerably high stereoregularity. The copolymer portion C of the composition of the present invention is a necessary portion for imparting high rigidity to the composition, and is a necessary portion for imparting high rigidity to the composition.
It is necessary that the amount is 60 to 90 parts by weight, preferably 70 to 85 parts by weight per 100 parts by weight. The intrinsic viscosity ηC of the part can be varied depending on the desired melt flow index range of the composition, and is from 0.4 to 3.0, preferably from 0.6 to 2.0. The higher the stereoregularity of the portion, the better, and the ratio of absorbance at 997 cm ^-1 and 974 cm ^-1 in the infrared absorption spectrum is 0.8 to 0.995, as described above. Copolymer portion A is a portion necessary for maintaining high impact resistance of the composition of the present invention, particularly at low temperatures, and has a relatively high ethylene content of 80 to 40% by weight. It is. If the ethylene content is outside this range, impact resistance will deteriorate. Therefore, this part preferably has low stereogenicity and has a limiting viscosity η
A is high, and the ratio of absorbance at 997 cm ^-1 and 974 cm ^-1 in the above infrared absorption spectrum is preferably 0.3 or less, and the limiting viscosity ηA is 2.0 to 7.0.
Particularly preferably 3.0 to 5.0. The presence of the copolymer moiety B significantly distinguishes the compositions of the invention from known compositions, with a propylene content of 90-70% by weight, preferably 85-75% and an ethylene content of 10% by weight. ~30% by weight, particularly preferably 15-25% by weight, and the ratio of absorbance at 997 cm ^-1 and 974 cm ^-1 in the infrared absorption spectrum is
It has a relatively high stereoregularity of 0.6 to 0.96. In addition, the intrinsic viscosity ηB of this part is 0.5 to 3.0
is preferred. Note that if the ethylene content is less than the above range, the elongation at break will be small. From the viewpoint of impact resistance, it is desirable that the intrinsic viscosity ηA of the copolymer portion A be larger than the intrinsic viscosity copolymers ηB and ηC of the other portions. The proportions of copolymer components A and B based on 100 parts by weight of the total composition are 5 to 15 parts by weight and 5 to 15 parts by weight, respectively.
30 parts by weight, preferably 5 to 15 parts by weight, and
10 to 25 parts by weight. It is preferable that the amount of copolymer component B be larger than that of copolymer component A from the viewpoint of obtaining a higher elongation at break. If the proportion of the copolymer portion C is less than the above range, the rigidity will decrease, and if it is greater than the above range, the impact resistance will decrease. Furthermore, if the proportion of the copolymer portion A is less than the above range, the impact resistance will be reduced, and if it is greater than the above range, the rigidity will be significantly reduced. The composition of the present invention can also be obtained by separately polymerizing the above-mentioned components and then mechanically mixing them, but preferably by polymerizing the same polymerization system but changing the polymerization conditions, so-called block co-polymerization. It can also be obtained by polymerization type polymerization, and the latter method is preferred. Preferred methods for producing the composition of the present invention include those specified by the following (a) catalyst, (b) polymerization method, (c) ethylene-propylene copolymerization method, and (d) polymer recovery method. That is, (a) anhydrous magnesium chloride and at least one selected from carboxylic esters, ethers, orthocarboxylic esters, and alkoxy silicones;
Using a catalyst consisting of a solid catalyst component obtained by contact treatment with a seed compound and then contact treatment with titanium halide and an organoaluminum compound,
(b) A bulk polymerization method using propylene itself as a solvent; (c)
Polymerization of propylene alone or copolymerization of a small amount of ethylene and propylene is carried out at a temperature of 50 to 80°C, and then the reaction ratio of ethylene and propylene is 20/80 to
After polymerization is carried out at 30 to 60°C under conditions of a 90/10 weight ratio, (d) unreacted monomers are removed by evaporation, filtered, or countercurrently washed with a propylene-based medium. This is a method to separate the The catalyst is anhydrous magnesium chloride and carboxylic acid ester, ether, orthocarboxylic acid ester,
It consists of a solid catalyst component obtained by contact treatment with one type of compound selected from alkoxy silicon and then contact treatment with titanium halide, and an organoaluminum compound. During the contact treatment with anhydrous magnesium chloride and one type of compound selected from carboxylic esters, ethers, orthocarboxylic esters, and alkoxy silicones, other compounds such as,
It is also possible to simultaneously contact organic compounds such as halogenated hydrocarbons, aromatic hydrocarbons, and alcohols, and inorganic compounds such as aluminum chloride, silica gel, and alumina. In addition, when carrying out a polymerization reaction using a catalyst consisting of the above-mentioned solid catalyst component and an organoaluminum compound, known stereoregularity improvers, for example,
It is more preferable to use esters, ethers, orthoesters, amine compounds, phosphorus compounds, etc. at the same time. Further, in order to maintain the catalytic activity, it is preferable to additionally charge a catalyst component, particularly an organoaluminum compound, during the polymerization. Further, when charging the catalyst component into the polymerization tank, it is preferable to disperse it in an inert organic solvent such as hexane, heptane, cyclohexane, toluene, xylene, or the like. Recovery of the polymer after completion of the polymerization is achieved by removing unreacted monomers by evaporation, filtering, or countercurrent washing with a medium containing propylene as a main component, followed by separation from the medium. At this time, it is also possible to add a compound that solubilizes the catalyst residue. By copolymerizing ethylene and propylene using a method that satisfies the four conditions (a), (b), (c), and (d) above, it is possible to achieve rigidity with high elongation at break and impact resistance. An excellent polymer composition is obtained. The present invention will be explained below with reference to Examples. In addition, the physical properties in Examples and Comparative Examples were measured as follows. (1) Intrinsic viscosity (η): Measured in a tetralin solution at 135°C. (2) Melt flow index (MI): JIS
Based on K7210. (230℃, load 2.16Kg) (3) Bending rigidity: ASTMD747 (20℃) (4) Dupont impact strength: According to JISK6718. (−
(10℃, 20℃) (5) Shalpy impact strength: ASTMD256 (-10
℃, 20℃) (6) Elongation at break: ASTMD638 Examples 1 to 5 (i) Synthesis of solid catalyst A solid catalyst is synthesized using a vibration mill that can be equipped with four crushing pots each having an internal volume of 4. In each pot under a nitrogen atmosphere, add 300 g of anhydrous magnesium chloride, 40 ml of ethyl orthoacetate, 60 ml of 1,2-dichloroethane and a grinding medium with a diameter of
A 12 mm steel ball weighing 9 kg was placed in a vibration mill and vibrated for 40 hours. Thoroughly dry 3 kg of the pulverized material obtained by the above method, place it in an autoclave with an internal volume of 50 kg in a nitrogen atmosphere together with 20 kg of titanium tetrachloride, and heat it at 80°C for 120 min.
Stir for a minute. Thereafter, it was allowed to stand and the supernatant liquid was removed. Then in the autoclave n-heptane 35
was added, stirred at 80°C for 15 minutes, left to stand, and washed to remove the supernatant liquid, which was repeated 7 times. Finally, 20% of n-heptane was added and stirred to form a solid catalyst slurry. A portion of it was sampled and the titanium content in the solid catalyst was analyzed.
Titanium was contained in the solid catalyst at 1.62% by weight. (ii) Polymerization reaction A jacketed autoclave with an internal volume of 100 was thoroughly dried, purged with nitrogen, and then purged with propylene, and then 25 kg of propylene was charged therein. 500 ml of n-heptane and diethylaluminium chloride in a flask with an internal volume of 1 that was purged with nitrogen.
4.8ml, methyl p-toluate 2.8ml and the above (i)
Add 1 g of the solid catalyst obtained in , stir for 1 minute,
Furthermore, 1 ml of triethylaluminum was added and the mixture was press-fitted into the above 100 autoclave. Next, a predetermined amount of hydrogen was charged, and then hot water was passed through the jacket to raise the internal temperature to 75°C to start polymerization. While keeping the internal temperature at 75℃, hydrogen was introduced to keep the hydrogen concentration constant, and to keep the catalyst activity constant, a solution of 3 ml of triethylaluminum dissolved in 57 ml of n-heptane was added at 0.5 ml/min. Polymerization was carried out for 2 hours while continuously pressurizing. Note that the hydrogen concentration was adjusted to a concentration that would yield a polymer having the intrinsic viscosity shown in column (1) of Table 1. Next, cold water was passed through the jacket to lower the internal temperature to 50°C, and 5 kg of liquid propylene was charged while purging the gas phase and lowering the hydrogen concentration. hydrogen concentration
When the concentration reached 0.5Vol%, charging of ethylene and hydrogen was started, and the gas phase concentration of ethylene and hydrogen was 40.5Vol each at a polymerization pressure of 29.6Kg/ ^cm2 gauge.
% and 0.5Vol% and polymerized for 7.5 minutes. Thereafter, the amount of ethylene charged was further increased, and polymerization was carried out for 2 minutes while maintaining the polymerization pressure at 32.5 Kg/cm ² gauge and the gas phase concentrations of ethylene and hydrogen at 48.5 Vol% and 0.4 Vol%, respectively. Immediately after the polymerization was completed, 50 ml of isopropanol was introduced under pressure to stop the reaction. Thereafter, the mixture was allowed to stand still to precipitate the polymer powder, and the supernatant propylene and ethylene were extracted. Next, 25 kg of propylene was introduced under pressure, and the mixture was stirred at 40°C for 10 minutes. After the mixture was allowed to stand still and the supernatant propylene was extracted, the remaining propylene was purged to obtain about 12 kg of a block copolymer composition. This powder was dried under reduced pressure at 60° C. and 150 mmHg for 10 hours, granulated with known additives, and its physical properties were measured by conventional methods. In addition, 10g of the above granulated pellets were added to n-decane.
The solution was dissolved in 300 ml and then cooled to 30°C to separate soluble and insoluble components. The insoluble matter was dispersed in n-decane at 110°C, filtered at 110°C, and separated into soluble and insoluble parts in n-decane at 110°C. From the soluble part, n
-Remove decane by vacuum distillation, and remove insoluble matter at 60°.
It was dried at 5 mmHg to obtain copolymer portion C. The intrinsic viscosity and the ratio of ethylene to propylene were measured for each part. The results are shown in Table 1. In addition, a drawing (solid line) shows the relationship between MI and elongation at break of the obtained copolymer composition.
Shown below. Comparative Examples 1 to 5 Using 10 g of titanium trichloride catalyst (TCY-24) manufactured by Marubeni Solve-A and 50 ml of diethylaluminium chloride as catalysts, a polymerization reaction was carried out in 100 ml of n-heptane using an autoclave with an internal volume of 300 ml. Ivy. Polymerization was continued for 2 hours at a polymerization pressure of 5 kg/cm ² gauge and a polymerization temperature of 70° C. while charging propylene and hydrogen. The hydrogen concentration during this time is shown in (I) in Table 1.
The concentration was adjusted to obtain a polymer having the intrinsic viscosity shown in the column. Next, the gas phase was purged while lowering the internal temperature to 55°C, and when the hydrogen concentration in the gas phase was reduced to 1 Vol% or less, hydrogen, ethylene, and propylene were charged, and the gas phase concentrations were 2.5 Vol% and 32 Vol%, respectively. , 65Vol%, and a total pressure of 2Kg/cm ² -gauge. The polymerization reaction was carried out under these conditions for 30 minutes, and then ethylene was injected at once to make the ethylene concentration 48 Vol, and the polymerization was carried out under these conditions for 20 minutes. Then charge 50 °C of methanol and 30 °C at 60 °C.
After stirring for a minute, 50% of water was added and stirred, and the aqueous layer was separated. Add 50% water to the heptane layer and add 2
After washing twice, it was over-dried. After that, Example 1~
After granulation in the same manner as in 5, the physical properties were measured and the particles were separated into each part. The results are shown in Table 1 and the drawing (dashed line).

【table】

[Table] As seen in Table 1 and the drawings, when the MI of the conventional block copolymer is relatively small, for example around 10, the elongation at break is almost the same as that of the block copolymer composition of the present invention. However, it decreases significantly as MI increases. However, in the block copolymer composition of the present invention, even if the MI increases, the elongation at break does not decrease much, and the practical physical properties are sufficiently satisfied.

[Brief explanation of the drawing]

The drawing shows the propylene block copolymer composition.
It is a diagram showing the relationship between MI and elongation at break (%), where the vertical axis shows elongation at break (%) and the horizontal axis shows MI. In addition, the solid lines in the figure are based on the example of the present invention, and the broken lines are based on the comparative example.

Claims (1)

[Claims] 1 (A) When dissolved and separated with a hydrocarbon having 6 to 20 carbon atoms, (1) it is soluble at 30°C, and propylene
5 to 15 parts by weight of a copolymer portion A consisting of 20 to 60% by weight and 80 to 40% by weight of ethylene, and having an intrinsic viscosity (hereinafter simply referred to as intrinsic viscosity) ηA of 2.0 to 7.0 in a tetralin solution at 135°C; (2) Insoluble at 30℃ and soluble at 110℃, propylene 90~
Consisting of 70% by weight and 10-30% by weight of ethylene,
Copolymer portion B5 having an intrinsic viscosity ηB of 0.4 to 3.0
~30 parts by weight, and (3) insoluble at 30°C and 110
Insoluble even at °C, propylene 100-95% by weight
and 0 to 5% by weight of ethylene, and 60 to 90 parts by weight of a copolymer portion C having an intrinsic viscosity ηC of 0.4 to 3.0, and (B) ηA is larger than ηB and ηC. A propylene block copolymer composition with high elongation. 2 The ratio of absorbance at 997 cm ^-1 and 974 cm ^-1 in the infrared absorption spectrum of copolymer portion C is 0.8
0.955, that of copolymer portion A is 0.3 or less, and that of copolymer portion B is 0.6 to 0.96. 3. The propylene block copolymer composition is prepared by contact-treating anhydrous magnesium chloride with at least one compound selected from carboxylic acid esters, ethers, orthocarboxylic acid esters, and alkoxy silicon, and then contact-treating with titanium halide. This is a bulk polymerization method using propylene itself as a solvent, using a catalyst consisting of a solid catalyst component and an organoaluminium compound, which can be obtained by polymerizing propylene alone or copolymerizing a small amount of ethylene and propylene.
Polymerization is carried out at a temperature of 50 to 80°C, then at 30 to 60°C under conditions where the reaction ratio of ethylene and propylene is 20/80 to 90/10 by weight, and unreacted monomers are removed by evaporation. 2. The propylene block copolymer composition according to claim 1, which is obtained by filtration or countercurrent washing with a medium containing propylene as a main component, followed by separation from the medium.