JP2818212B2 - New polypropylene sheet - Google Patents

Description

The present invention relates to a novel sheet of polypropylene. More specifically, the present invention relates to a sheet of polypropylene having high syndiotacticity.

(Prior art)

Syndiotactic polypropylene has been known for a long time, but the conventional method of low-temperature polymerization with a catalyst consisting of a vanadium compound, ether and organoaluminum is said to have poor syndiotacticity and elastomeric properties. But it was hard to say that it inherently characterizes syndiotactic polypropylene. On the other hand, JAEWEN et al. Discovered for the first time that a transition metal catalyst having an asymmetric ligand and a catalyst composed of aluminoxane could produce polypropylene with good tacticity such that the syndiotactic pentad fraction exceeded 0.7. (J.
Am. Chem. Soc., 1988, 110, 6255-6256).

[Problems to be solved by the invention]

On the other hand, one of the major uses of isotactic polypropylene is a sheet, which is used as a sheet having relatively good physical properties, but has a problem that the transparency is somewhat insufficient. A sheet was desired.

[Means for solving the problem]

Means for Solving the Problems The inventors of the present invention have solved the above problem and have intensively searched for a polyolefin sheet having excellent transparency.

That is, in the present invention, the syndiotactic pentad fraction is
Extrusion molding of polypropylene of 0.7 or more has a thickness of 0.0
It is a sheet with good transparency of 05 to 5 mm.

Examples of the catalyst used for producing syndiotactic polypropylene in the present invention include the compounds described in the above-mentioned documents.
Any material that can produce a polypropylene having a syndiotactic pentad fraction of 0.7 or more can be used.

As a transition metal catalyst having an asymmetric ligand, isopropyl (cyclopentadienyl-
Examples thereof include 1-fluorenyl) hafnium dichloride and isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride. The aluminoxane is represented by a general formula: (Wherein R is a hydrocarbon residue having 1 to 3 carbon atoms). Examples thereof include methylaluminoxane wherein R is a methyl group and n is 5 or more, preferably 10 or more. . The use ratio of the aluminoxane to the transition metal catalyst is 10 to 100,000,000 mole times, usually 50 to 500.
It is 0 mole times. The polymerization conditions are not particularly limited, and a solvent polymerization method using an inert catalyst, a bulk polymerization method substantially free of an inert medium, and a gas phase polymerization method can be used. Generally, the polymerization is carried out at a temperature of -100 to 200 ° C. and at a pressure of normal pressure to 100 kg / cm ² -G. Preferably, it is -100 to 100 ° C and normal pressure to 50 kg / cm ² . The preferred molecular weight is generally about 0.5 to 3.0 dl / g as the intrinsic viscosity measured with a 135 ° C. tetralin solution. The tacticity is 0.7 or more, preferably 0.8 or more, as a syndiotactic pentad fraction. 0.7
If it is smaller, the properties as crystalline polypropylene are not sufficient and the physical properties are poor, which is not preferable.

In the present invention, various known additives such as an antioxidant are added to the syndiotactic polypropylene synthesized by the above method, granulated as required, and then extruded to form a sheet. The method of forming the sheet is not particularly limited, and it is sufficient to use an apparatus provided with a die having a desired shape for forming a sheet in a usual extruder. At this time, since syndiotactic polypropylene has a relatively low crystallization rate, it is more preferable to use a nucleating agent or to devise cooling of the extruded sheet.

〔Example〕

 Hereinafter, the present invention will be described with reference to Examples.

Example 1 0.2 g of isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride obtained by lithiation of isopropylcyclopentadienyl-1-fluorene synthesized according to a conventional method, reaction with zirconium tetrachloride and recrystallization. And 30 g of methylaluminoxane manufactured by Toyo Akzo Co., Ltd. (polymerization degree: 16.1), polymerized in an autoclave with an internal volume of 200 at a polymerization pressure of 3 kg / cm ² -G at 20 ° C. for 2 hours, and then decalcified with methanol and methyl acetoacetate The mixture was treated, washed with an aqueous hydrochloric acid solution, and then filtered to obtain 5.6 kg of syndiotactic polypropylene. According to ¹³ C-NMR, the polypropylene had a syndiotactic pentad fraction of 0.935, an intrinsic viscosity measured at 135 ° C. of a tetralin solution at 1.45 dl / g, and M measured at 1,2,4-trichlorobenzene.
W / MN was 2.2. After adding a known stabilizer and 10/10000 talc to this polypropylene and granulating, the temperature was 210 ° C with a downward die in a 40 mmφ extruder and the screw rotation speed was 100 rp.
A sheet having a width of 400 mm and a thickness of 0.5 mm was prepared. The following physical properties of this sheet were measured.

Haze% ASTM D-1003 Yield stress kg / cm ² ASTM D-638 Elongation at break% ASTM D-638 Tensile modulus kg / cm ² ASTM D-638 Haze 15.5%, Yield stress 246 kg / cm ² , Break Time growth 6
The tensile modulus was 77% and the tensile modulus was 5900 kg / cm ² .

Comparative Example 1 The isotactic pentad fraction by ¹³ C-NMR was 0.1.
980 and the intrinsic viscosity measured with 135 ° C tetralin solution is
MW / MN measured with 2.20dl / g, 1,2,4-trichlorobenzene
Was 5.5, and was the same as Example 1 except that commercially available isotactic polypropylene was used. Haze 5
8.7%, yield point stress 326 kg / cm ² , elongation at break 954%, tensile modulus 10700 kg / cm ² . The strength is good, but the transparency is poor.

Comparative Example 2 Ethylene content by ¹³ C-NMR was 4.2 wt%, absorption of all methyl groups was 0.931 for 5 mm propylene chains aligned with mmmm, and intrinsic viscosity measured at 135 ° C. tetralin solution was 2.26. MW / MN measured with dl / g and 1,2,4-trichlorobenzene was 5.5. The procedure was the same as in Example 1 except that a commercially available propylene ethylene copolymer was used. Haze 36.5%, yield point stress 227kg / cm ² , elongation at break 912%,
The tensile modulus was 4,400 kg / cm ² . The transparency is better than the propylene homopolymer of Comparative Example 1, but the strength and the transparency are inferior to Example 1.

Example 2 By changing the polymerization conditions in Example 1, according to ¹³ C-NMR, the syndiotactic pentad fraction was 0.915, and the intrinsic viscosity measured at 135 ° C. tetralin solution was 1.71 dl / g, 1,2, , 4-
A syndiotactic polypropylene having a MW / MN of 1.9 measured in a trichlorobenzene solution was obtained, and a sheet was similarly prepared. The haze was 12.5%, the yield point stress was 226 kg / cm ² , the elongation at break was 720%, and the tensile modulus was 6100 kg / cm ² .

〔The invention's effect〕

The sheet of the present invention has relatively excellent strength and extremely excellent transparency, and is extremely valuable industrially.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-4928 (JP, A) JP-A-63-60726 (JP, A) JP-A-54-141854 (JP, A) JP-A-1- 182346 (JP, A) JP-A-1-110122 (JP, A) JP-A-2-41305 (JP, A) JP-A-62-294526 (JP, A) JP-A-60-135242 (JP, A) JP-A-61-189920 (JP, A) JP-A-3-149206 (JP, A) JP-A-3-81130 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 47/00-47/96 C08J 5/18 C08F 110/06

Claims (1)

(57) [Claims] (1) a syndiotactic pentad fraction of 0.7
The thickness obtained by extruding the above polypropylene is 0.005
Sheet with good transparency of ~ 5mm.