JPS58104906A - Polypropylene film having high rigidity - Google Patents

Abstract

PURPOSE:The titled film, prepared by using a specific polypropylene with a limited isotactic pentad fraction, capable of forming thin films, suitable for packaging materials for automatic packaging machines, and improving the operability. CONSTITUTION:A film, prepared by using a crystalline polypropylene having the relation between an isotactic pentad fraction (P) and a melt flow rate index (MFR) of the formula, 0.450-0.650 isotactic pentad fraction (P) and 0.750-0.900 isotactic pentad fraction (P) of extracts obtained by successively extracting with boiling n-hexane and boiling n-heptane and 3.0-6.0% total amount of the extracts, and obtained by the inflation method.

Description

[Detailed description of the invention] The present invention relates to a highly rigid polypropylene film.

Polypropylene molded products have excellent heat resistance, chemical resistance, and electrical properties, and the films in the molded products also have good rigidity, tensile strength, and optical properties.

However, depending on the specific use of the film, these properties may not be sufficient, which limits the expansion of specific uses. Particularly in terms of rigidity, polypropylene biaxially stretched film is inferior to cellophane and polyester films, so it is difficult to automatically wrap it in overlap packaging or twist packaging. Furthermore, the use of the film in connection with electrical articles has the disadvantage that it is prone to wrinkles due to its poor rigidity, and that workability is reduced if attempts are made to avoid wrinkles. Furthermore, if tensile strength can be improved along with rigidity, further thinning can be achieved.

Generally, crystalline polypropylene (hereinafter referred to as polypropylene)
As a method for improving the rigidity of, for example, paratertiary butylbenzoic acid aluminum salt or (lt
3), (2s4) There is a method of adding an organic nucleating agent such as dibenzylidene sorbitol, but this increases the cost and significantly reduces the physical properties of the surface, such as gloss, impact strength, and tensile elongation. There is a drawback. Another method for improving rigidity is to add various inorganic fillers such as talc, calcium carbonate, barium sulfate, mica, asbestos, and calcium silicate to polypropylene. However, the polypropylene film produced by this method has the drawback that the characteristics of the polypropylene molded product are not only lost in quantity and transparency, but also the same physical properties as in the case of adding an organic nucleating agent mentioned above are observed. accompanies.

The present inventors have intensively researched a method for improving the rigidity of a 1-polybo-1-pyrene film that does not have the drawbacks associated with the above methods. As a result, it is possible to use polypropylene having a limited isotactic pentad fraction and composition (extractable fraction) according to the present invention, which will be described later. The present invention was completed knowing that the following could be obtained. Such polypropylene is
It can be manufactured by the method described in the specification of Japanese Patent Application No. 1983 filed by the same applicant as the present application and filed in the same month as the present application.

As is clear from the above description, an object of the present invention is to provide a polypropylene film that has high rigidity and can be used in a wide range of specific applications. Other objectives will become apparent from the description below.

The present invention has an isotactic pentad fraction (P) and a melt flow rate index (VFR) of 1.0.
There is a relationship of 0≧P≧0.015/'ogMFR-1-0.955. The fraction (P) is 0.
450 to 0.650 and 0.750 to 0.900, and (1) is a high 1411 polypropylene film made of crystalline polypropylene in which the total amount of the extractable material of (2) is 3% to 6%.

The structure and effects of the present invention will be explained in detail below. Isotactic pentad fraction (Crow is the isotactic fraction of pentad units in the polypropylene molecular chain, macromoI!e cuJFes868) (1
975) K Measured based on published methods.

In this measurement method, curvature-NMR is used. P<0
, 01510g In the case of MFR-1-0,955, the desired high rigidity product cannot be obtained even if the above-mentioned conditions (1) and (2) are satisfied, and since P is a fraction, it is 1.00. is the upper limit. Next, several parts of boiling n-hexane extract are contained in crystalline polypropylene, and the nuclear fraction P of this substance can be varied by a wide range, for example from 0.30 to 0.70, by a propylene polymerization method. It can change. This extractable fraction in the polypropylene used in the present invention must have an internal pressure in the range of P 0.450 to 0.650.

Even if it is less than 0.4.50, the rigidity of the product of the present invention can be improved, but on the other hand, the effect of improving other physical properties of the product of the present invention, such as hardness, heat deformation humidity, etc., is insufficient.

Similarly, the fraction P of the boiling n-hexane extract refers to the portion of the extraction residue obtained by extracting the polypropylene used in the present invention with boiling n-hexane, which is further extracted. This extractable fraction in the polypropylene used in the present invention must have a P in the range of 0.7 i'+ 0 to 0.850.

Although the rigidity of the product of the present invention can be improved even if it is less than 0.750,
On the other hand, the product of the present invention has the same drawbacks as the above-mentioned boiled n-hebutane extract in other physical properties. Pigeon houses with P that is higher than those of the products of the present invention will have reduced punching impact strength and transparency as well as a decrease in extractables. The total extraction capacity of the sequential extracts with boiling n-hexane and boiling $n-hebutane should be 3.0 to 6.0% (by weight) based on the raw polypropylene. 3. If it is less than C1, the transparency, punching impact strength and stretchability will be reduced, and if it is more than 6.0, the stiffness training effect of the product of the present invention will be insufficient. The proportion of the boiling n-hexane extract in the total extracted water is not limited. However, the above-mentioned patent application was filed in 1982.
When nine polypropylene produced by the method of No. 1 is extracted sequentially with boiling n-hexane and boiling n-hebutane, the amount of the former extracted is usually 0.5 to 4% relative to the polypropylene.
．． The extraction amount of the latter is in the range of 2 to 4. Sequential extraction is performed as follows. That is, a granulated product made by mixing a small amount of heat stabilizer (for example, 0.1 part of 2,6-di-tert-butyl-para-cresol) with polypropylene powder and granulating it using an extruder is then processed using a pulverizer. The pulverized product was passed through a 20-mesh (Tyler) sieve, and 3 f of the 9 passages were first sieved with a 100-mesh sieve using a Soxhlet extractor.
of boiling n-hexane and then with 100-degree boiling n-hexane for 6 hours each, and each extracted fraction was precipitated, separated, dried, and weighed. According to the method of 71'j1MF RFiJI8K 7210, the measurement was carried out at 230°C and a load of 2,160 f÷.

"・1 The present invention can be widely applied to various types of polypropylene films, and can exhibit their high rigidity.

The highly rigid film of the present invention can be made thinner than conventional equivalent products, and can also be used as a packaging material for automatic packaging machines to improve workability.

The present invention will be explained below with reference to Examples. The methods for measuring various physical properties in each Example and Comparative Example were as follows.

Young's modulus A8TM 0888 (Kff/Shizu2) Tensile yield strength A8TM D882 (Kpf
/- Rehaze A8TM DIO03 (%) Punching impact strength A8TM D781 (~f-prepared) Example 1.2 Ratio examples 1 to 4 Polypropylene listed in Table 1 below 0 to 7 enol heat stabilizer each to .00-, calcium stearate 0,
005 rl and 0.01~ of silica fine powder are added,
Mix for 10 minutes at room temperature using a high-speed stirring mixer (Note: Hensier 1 (-- Lumixer-1 brand name), and mix #f.
l, *-X l”J-□l-Q % 40 m (
7) Granulation was performed using fQ m□□. Next, the granulated material was processed using a CYT film forming machine manufactured by Yamaguchi Seisakusho ■ at a temperature of 215° C. and a cooling water temperature of 20° C., with a fold of 150 mm and a thickness of 30 mm.
(7) n-7F'-'''1717F-''1-9 The film was then left in a constant temperature room with a room temperature of 23°C and a humidity of 501C for 72 hours to adjust its condition.

Then, physical property values were measured as shown in Table 1 below.

Table 1: Blown film production test As is clear from Table 1, the isotactic pentad fraction P in the total polymer and each extracted amount, and the total extracted amount were produced using polypropylene within the range of the present invention. Example 1
．． 2 inflation film, young car heavy bottom 4
It has excellent physical properties and maintains sufficient strength and transparency as a highly rigid polypropylene film. On the other hand, in each comparison where either the isotactic pentad fraction (three types) or the total extraction amount is outside the scope of the present invention, it is clear that one or more of the film physical properties are Inferior to inventions. In particular, even if the isotactic pentad fraction P in the total polymer and each extracted amount is within the range of the present invention,
In Comparative Example 3, in which the total extraction amount was insufficient, the Young's modulus and tensile yield strength were satisfactory, but the haze and punching impact strength were significantly inferior to the product of the present invention, and the isotactic pentad in a specific range It is clear that the coexistence of fractions, n-C, and n-07 extracts in amounts within a certain range is necessary. In addition, in Comparative Example 4, in contrast to Comparative Example 3, the total extraction amount is within the range of the present invention, but n-C and n-
Isotactic pentad fraction P relative to C1 extract
is out of scope. As a result, the Young's modulus and tensile yield strength are poorer than those of the respective implementations. On the other hand,
Contrary to the case of Comparative Example 3, the haze and punching impact strength were good.

Example 3.4 Comparative Examples 6 to 7 Each of the polypropylenes listed in Table 2 below was added with 0.005 to 0.005 of a phenolic heat stabilizer and 0.05 to 0.00 of calcium stearate.
005- and ultrafine silica (average particle size 0.I It
) 0.0025- was added and mixed at room temperature with a high-speed stirring mixer, and the mixture was granulated using an extrusion granulator with a diameter of 40-. Then what about the granules? - Extrusion using a die-type film forming machine at a resin temperature of 250°C and rapid cooling with a 20°C cooling roll to produce a sheet with a thickness of 1 inch.9. This sheet was heated with hot air at 150 C for 70 seconds, and then simultaneously stretched by a factor of 7 in both longitudinal and lateral directions at a speed of 5 centimeters/second using a biaxial stretching machine to obtain a biaxially stretched film with a thickness of 20 μm. The physical properties of this film are shown in Table 2.

Kancho Shitomo.

As is clear from Table 2, the isotactic pentad fraction P in the total polymer and each extract and the total extraction amount of the two in Example 3.4 were produced using polypropylene within the range of the present invention. The axially stretched film has excellent four physical properties including stretchability and Young's modulus, and maintains various strengths and transparency sufficient for a polypropylene high rigidity film. On the other hand, in each comparative side where the isotactic pentad fraction (3 types) or total extraction amount is outside the range of the present invention, one or more of the physical properties of the film clearly differs from the product of the present invention. Inferior. In particular, the comparative example film with insufficient total extractable amount was insufficient in stretchability and all film properties, and the polypropylene used for the product of the present invention contained a certain amount of n-C. It is clear that it is necessary to contain

that's all

Claims (1)

[Claims] (1) ■ Isotactic pentad fraction (Pl and melt flow rate index (MFR) are 1.00≧
There is a relationship of P≧0,015 log M P R+ 0.955, and the isotactic pentad fraction (P) of extracts extracted sequentially with boiling n-hexane and boiling n-hexane is 0.450, respectively. ~0.650, and 0.750 to 0.900, (2) A high rigidity polypropylene film made of crystalline polypropylene having a total amount of 3.0% to 6.0% of the extractables described in (2) above. (2) A blown polypropylene film made using the crystalline polypropylene of claim (1); (3) A high-rigidity polypropylene biaxial film made of the crystalline polypropylene of claim (1). Stretched film.