JPH01165645A - Production of polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the title highly crystalline composition without problems such as an odor and a decreased MW, by melt-mixing a specified crystalline propylene copolymer (or a product thereof treated with alcohol) with a crystalline PP and irradiating the mixture with a radiation. CONSTITUTION:30-0.01mol% alkenylchlorosilane (a) having at least one Si-Cl bond (e.g., vinyltrichlorosilane) is copolymerized with propylene (b) in the presence of a stereoregular polymerization catalyst (c), and the product is optionally treated with alcohol to obtain a crystalline propylene copolymer (or a product thereof treated with alcohol) (B) of an intrinsic viscosity <=10 (in a tetralin solution at 135 deg.C). A composition obtained by melt-mixing 100 pts.wt. crystalline PP (A) with 0.01-10 pts.wt. component B is irradiated with a radiation at several tens of rad to several tens of Mrad.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a polypropylene resin composition containing a silane compound. Specifically, the present invention relates to a method for producing a highly crystalline polypropylene resin composition, which comprises subjecting a mixture of polypropylene containing a silane compound in its main chain and polypropylene not containing the silane compound to a specific treatment.

[Prior Art] A method has already been proposed in which polypropylene is treated with a radical generator and crosslinked to improve its physical properties (for example, JP-A-61-16944).

[Problem that the invention seeks to solve]

The above method is relatively simple and has a large effect on improving physical properties, but since it uses peroxide, it inherently has problems with odor, a problem with molecular weight reduction due to decomposition of polypropylene, and the need to perform molding and crosslinking at the same time. have.

[Means for solving problems]

The present inventors have diligently searched for a method for producing a highly crystalline polypropylene resin composition that solves the above problems, and have completed the present invention.

That is, the present invention provides a high-density polymerization method characterized in that a molten mixture of a crystalline propylene copolymer obtained from alkenylchlorosilane and propylene using a stereoregular catalyst or an alcohol-treated product thereof and crystalline polypropylene is irradiated with radiation. This is a method for producing a crystalline polypropylene resin composition.

In the present invention, the method for producing a crystalline propylene copolymer obtained by using alkenylchlorosilane and propylene using a stereoregular catalyst includes, for example, U.S. Pat.
, 223,686, and the method can be used as is. As the alkenylchlorosilane, one having at least one 5i-C1 bond is used,
For example, vinyltrichlorosilane, allyltrichlorosilane, butenyltrichlorosilane, pentenyltrichlorosilane, and the 5i-Cj! of these monomers. Joining 1~
Examples include those in which two groups are substituted with alkyl groups or hydrogen. Since then, many catalysts with improved performance have been disclosed as stereoregular catalysts, and these can be used.In addition to the solvent method using an inert solvent, bulk polymerization methods and gas phase polymerization methods have been used as stereoregular catalysts. A polymerization method can also be used. Here, a preferred example of the stereoregular catalyst is a catalyst system consisting of a transition metal catalyst and an organometallic compound, and a titanium halide is preferably used as the transition metal catalyst. A catalyst system consisting of titanium trichloride obtained by reduction with or modified with an electron-donating compound, an organoaluminum compound and, if necessary, a stereoregularity improver such as an oxygen-containing organic compound, magnesium halide, etc. A transition metal catalyst obtained by supporting titanium halide on a carrier or a carrier treated with an electron-donating compound or a reaction product of magnesium chloride and alcohol is dissolved in a hydrocarbon solvent, and then a precipitant such as titanium tetrachloride is added. The transition metal catalyst and organoaluminum compound obtained by treatment with a hydrocarbon solvent, treated with an electron-donating compound such as an ester or ether as necessary, and then treated with titanium tetrachloride. Catalyst systems consisting of stereoregularity enhancers such as oxygen organic compounds are exemplified (various examples are described, for example, in the following literature: Ziegler-Natta
Catalystsand Polymerizat
ion by John Boor Jr. (Acad
emicPress), Journal of Ma
cromorecular Science-Revie
ws in Macromolecular Chess
istry and Physics.

C24(3), 355-385 (1984), C25
(1), 57B-597 (1985)).

Here, preferred examples of the stereoregularity improver or electron-donating compound include oxygen-containing compounds such as ethers, esters, orthoesters, and alkoxy silicon compounds.
Further, alcohols, aldehydes, water, etc. can also be used as electron-donating compounds.

As the organoaluminum compound, trialkylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, alkyl aluminum civalide can be used, and examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, hexyl group, etc. Examples of halides include chlorine, bromine, and iodine.

Here, the polymerization ratio of alkenylchlorosilane and propylene is not particularly limited as long as the resulting polymer maintains crystallinity, but usually alkenylchlorosilane is 30%
The catalyst activity during polymerization is mol% to 0.01 mol%.
Alternatively, it is preferable because it can be mixed with the crystalline polypropylene to be mixed and because the effect of improving physical properties is sufficient. The molecular weight of the polymer is not particularly limited, but it should be extremely high, for example, not more than 10 in intrinsic viscosity measured in a tetralin solution at 135°C.

In the present invention, the crystalline polypropylene to be mixed with the crystalline propylene copolymer obtained by using the above-mentioned alkenylchlorosilane and propylene using a stereoregular catalyst is not particularly limited, and as necessary, polymers of various molecular weights, Alternatively, random or block copolymers with other olefins such as ethylene can be used.6 The object of the present invention is to mix this alkenylchlorosilane and propylene with a crystalline propylene copolymer obtained using a stereoregular catalyst. The goal is to improve the physical properties of crystalline polypropylene, and its composition does not matter.

To obtain the crystalline polypropylene, it is sufficient to use the above-mentioned catalyst and polymerization method during polymerization, and many methods have already been proposed for producing copolymers. Copolymerization or so-called block copolymerization in which only propylene is first polymerized and then other olefins and propylene are polymerized may be used.

There is no particular restriction on the mixing ratio of the crystalline propylene copolymer obtained from alkenylchlorosilane and propylene using a stereoregular catalyst and the crystalline polypropylene, but usually alkenylchlorosilane and propylene are mixed with 100 parts by weight of crystalline polypropylene. The crystalline propylene copolymer obtained using a stereoregular catalyst weighs about 0.01 to 10 parts by weight. If it is less than 0.01 part by weight, there is no effect of improving the physical properties, and if it is added in excess of 10 parts by weight, the effect of improving the physical properties of crystalline polypropylene is not increased.

Furthermore, by copolymerizing so that the alkenylchlorosilane content in the polymer is extremely small, for example, 0.1 wt% or less, it is also possible not to mix polypropylene that does not contain alkenylchlorosilane. Furthermore, the copolymer of alkenylchlorosilane and propylene can be treated in advance with a lower alcohol such as methanol, ethanol, propatool, butanol, or the like.

Examples of the radiation used in the present invention include T-rays and electron beams, and the irradiation dose is several tens of rad to several tens of Mrad.
It is common to irradiate to a certain extent, and irradiating more than this has no particular effect, and below this, there is almost no effect.There is no particular restriction on the temperature during irradiation, and it is sufficient as long as it is below the heat resistance temperature of polypropylene. However, it is sufficient to do it at room temperature.

In the present invention, there is no particular restriction on the method of mixing the above-mentioned components, and they can be sufficiently mixed by a general method such as pre-mixing with a Henschel mixer, followed by melt-mixing and granulation with an extruder. At this time, it is of course possible to mix various known additives such as stabilizers.

〔Example〕

The present invention will be further explained with reference to Examples below.

Example 1 A vibratory mill equipped with four grinding pots each having an internal volume of 41 and containing 9 kg of steel balls each having a diameter of 12 m was prepared. 300g of magnesium chloride and 60al of tetraethoxysilane in each pot under nitrogen atmosphere! , α, α, α-Trichlorotoluene (45 jd) was added and the mixture was pulverized for 40 hours. 300 g of the thus obtained co-pulverized material was put into a 51 flask, and 1.511 g of titanium tetrachloride and 1.54 g of toluene were added. and 100℃
After stirring for 30 minutes, and then removing the supernatant, 1.51 liters of titanium tetrachloride and 1.51 liters of toluene were added again.
The mixture was stirred at 100° C. for 30 minutes, and then the supernatant was removed. Thereafter, the solid content was repeatedly washed with n-hexane to obtain a transition metal catalyst slurry. When a part of the sample was sampled and the titanium content was analyzed, the titanium content was 1.9 wt%.

In a pressure-resistant glass autoclave with an internal volume of 2001 d, 40+ d of toluene and 100 mg of the above transition metal catalyst were placed in a nitrogen atmosphere.
5 diethylaluminum chloride 0.128d, p-
Add 0.06 d of methyl toluate and 0.20 d of triethylaluminum, then press in 6.0 g of vinyltrichlorosilane, then charge propylene to 5 kg/C-, and keep the pressure constant at 70"C for 2 hours. The slurry was then taken out, filtered and dried to obtain 28 g of powder.The intrinsic viscosity (hereinafter abbreviated as η) measured with a tetralin solution at 135°C was determined using a differential thermal analyzer.
When the melting point and crystallization temperature were measured as the maximum peak temperature by increasing or decreasing the temperature at 0°C/sin, the obtained powder had an η of 1.61, a melting point of 156°C, and a crystallization temperature of 118°C. It was a certain crystalline polypropylene. According to elemental analysis, it contained 1.3@t% of vinyltrichlorosilane units.

Separately, propylene was polymerized, η = 1.65, and the extraction residual rate (hereinafter abbreviated as II) when extracted with a Soxhlet extractor. The powder weight after extraction/the powder weight before extraction was 100
A polypropylene having a percentage (expressed as a fraction) of 97.1% was obtained.

900 g of the polypropylene powder obtained here, 20 g of the above copolymer, a phenolic stabilizer in a weight ratio of 10/10,000 (to polypropylene), and calcium stearate in a weight ratio of 15/10,000 were added and granulated to obtain a mixture.

This mixture was then irradiated with 5 Mrad of T-rays.

Melt flow index (ML ASTM t11238 (230°C)) using a pellet irradiated with γ-rays
An injection sheet with a thickness of 1 m was made, and the bending stiffness (ASTM 0747-63 (20
°C)) was measured.

The results obtained are shown in the table.

Comparative Example 1 Physical properties were measured in the same manner as in Example 1 except that the copolymer of vinyltrichlorosilane and propylene was not used.

The results are shown in the table.

Example 2 The same procedure as Example 1 was carried out except that allyltrichlorosilane was used instead of vinyltrichlorosilane. The copolymer obtained here contained 2.3 wL% allyltrichlorosilane.
η was 1.34, and the melting point was 135°C.

The results are shown in the table.

Example 3 The same procedure as Example 1 was carried out except that after copolymerization, 40 methanol was pressurized into the reactor and the copolymer treated with alcohol was used.

The results are shown in the table.

〔Effect of the invention〕

By carrying out the method of the present invention, it is possible to produce a polypropylene resin composition with excellent physical properties, which is extremely valuable industrially.

Claims (1)

[Claims] 1. Highly crystalline polypropylene characterized by irradiating a molten mixture of a crystalline propylene copolymer obtained from alkenylchlorosilane and propylene using a stereoregular catalyst or an alcohol-treated product thereof and crystalline polypropylene with radiation. A method for producing a resin composition.