JPH0333138A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain a polypropylene resin composition improved in properties such as bending modulus, tensile yield strength and impact resistance by melt- mixing a crystalline polypropylene with a specified amount of a radiation- crosslinked propylene/alkenylsilane copolymer. CONSTITUTION:Propylene is copolymerized with an alkenylsilane (e.g. vinylsilane) in the presence of a catalyst comprising a transition metal compound (e.g. titanium trichloride) and an organometallic compound (e.g. triethylaluminum). The obtained copolymer is crosslinked by irradiation with a radiation (e.g. electron beams). 100 pts.wt. crosslinked propylene/alkenylsilane copolymer is melt-mixed with at least 0.01 pt.wt. crystalline polypropylene to produce a polypropylene resin composition. The crystalline polypropylene which can be used includes a copolymer of propylene with a small amount of ethylene or the like as well as a propylene homopolymer.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to polypropylene resin compositions.

Specifically, the present invention relates to a crystalline polypropylene resin m-acid formed by blending a specific crosslinked polypropylene.

[Prior art]

Crystalline polypropylene has relatively good rigidity, and copolymerized with other olefins such as ethylene is used in many applications as an inexpensive polymer with an excellent balance of rigidity and impact resistance. However, polypropylene has various problems such as a relatively low degree of crystallinity and not exhibiting excellent physical properties such as original stiffness and transparency, and in some cases, a long molding time. For this purpose, various nucleating agents have been added, and among them, the method of using a polymeric substance as a nucleating agent is extremely effective and excellent even in a small amount (Japanese Patent Laid-Open No. 60-139731. 61-16944 etc.)
However, the former has the problem that the polymeric substance that acts as a nucleating agent is expensive, and the latter has problems such as the complicated operation to obtain cross-linked polypropylene and the unique odor of cross-linked polypropylene. .

[Problem to be solved by the invention]

The above-mentioned method using cross-linked polypropylene is relatively inexpensive and effective, so if cross-linked polypropylene that is simple and free of the odor characteristic of cross-linked polymers can be obtained, it will be possible to widely improve the physical properties of crystalline polypropylene. It is expected that it will be possible.

(!I! Means for Solving the Problem) As a result of intensive search for a crystalline polypropylene resin composition that solved the above-mentioned problems, the present inventors found that the above-mentioned problems could be solved by using a specific polypropylene, and the present invention is presented. That is, the present invention has completed a polypropylene resin &Iltrium in which 100 parts by weight of crystalline polypropylene is melt-mixed with 0.01 parts by weight or more of a copolymer of propylene and alkenylsilane crosslinked by radiation irradiation. It is a thing.

The copolymer of alkenylsilane and propylene used in the present invention, which is obtained by polymerizing alkenylsilane and propylene in the presence of a transition metal compound and an organometallic compound, is disclosed in U.S. Pat. No. 3,223.686. The creation of an elastic copolymer by crosslinking a copolymer of ethylene, propylene, and alkenylsilane is described in Section 3, 64 of the same.
4.306, it is not known that crystalline propylene-alkenylsilane copolymers can be crosslinked by radiation. The alkenylsilane used for copolymerization in the present invention is an alkenylsilane containing at least one S Those having an i-tl bond are preferably used, for example, the general formula 11tc=cH-(C11g)a-5iHP
Examples include compounds represented by Rs-p (where n is 0-12, p is 1-3, and R is a hydrocarbon residue having 1 to 12 carbon atoms), specifically vinylsilane, allylsilane, butenylsilane. , pentenylsilane, or a compound in which H of one to three 5i-H bonds of these monomers is replaced with chloro.

In the present invention, the crystalline propylene-alkenylsilane copolymer is obtained by polymerization using a catalyst consisting of a transition metal compound and an organometallic compound. Many of the performance-improved catalysts disclosed for the polymerization of propylene can be used without difficulty.

As the polymerization method, in addition to a solvent method using an inert solvent, a bulk polymerization method and a gas phase polymerization method can also be employed. Here, as the catalyst consisting of a transition metal compound and an organometallic compound, a titanium halide is preferably used as the transition metal compound, and an organic aluminium compound is preferably used as the organometallic compound. A catalyst system consisting of titanium trichloride obtained by reducing with aluminum or modified with an electron-donating compound, an organoaluminium compound, and further an electron-donating compound such as an oxygen-containing organic compound as necessary, or a magnesium halide. A catalyst system consisting of a transition metal compound catalyst obtained by supporting titanium halide on a carrier such as or treated with an electron-donating compound, an organoaluminium compound, and an electron-donating compound such as an oxygen-containing organic compound as necessary. Alternatively, the reaction product of magnesium chloride and alcohol is dissolved in a hydrocarbon solvent, and then treated with a precipitant such as titanium tetrachloride to make it insoluble in the hydrocarbon solvent. treated with a compound,
Then, a transition metal compound catalyst and an organoaluminum compound obtained by a method such as treatment with titanium halide,
Catalyst systems made of electron-donating compounds such as oxygen-containing organic compounds are exemplified as necessary (for example, various examples are described in the following documents: Ziegler-Natt
a Catalysts and Polymeriz
ation by John Door Jr.
demic Press), Journal
of Macromorecular 5ienc
eReviews in Macromole
cular Chemistry and Phys
ics, C24(3) 355-385 (1984),
C25(1) 578597 (1985)).

As the electron-donating compound, oxygen-containing compounds such as ethers, esters, orthoesters, and alkoxy silicon compounds are generally preferred, and alcohols, aldehydes, water, and the like can also be used.

As an organoaluminum compound, trialkylalkξ
nium, dialkylalgonium halide, alkylaluminum sesquihalide, and alkylalnumium cybaride can be used. Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, and hexyl group, and as the halide, chlorine , bromine, and iodine.

There is no particular restriction on the polymerization ratio of alkenylsilane and propylene, but in order to easily adjust the degree of crosslinking to an appropriate range, alkenylsilane is usually 0.001 to 3.
About 0.7%, preferably 0.7%. Ol~5 mol%.

The molecular weight of the polymer is not particularly limited, but it is preferably about the same molecular weight as the crystalline polypropylene whose physical properties are to be improved by mixing. In some cases, polymerization may be performed in the same manner as crystalline polypropylene (composition, molecular weight, etc.) except that it does not contain alkenylsilane.

In the present invention, the crystalline propylene-alkenylsilane copolymer is irradiated with radiation prior to use. Examples of the radiation include α rays, β rays, T rays, X rays, neutron beams, and synchrotron radiation, but γ rays and electron beams are usually preferably used. The irradiation dose is usually several r
ad to several tens of Mrad, and although it varies depending on the alkenylsilane content, the usual guideline is that the gel fraction calculated as boiling xylene insoluble matter is 0.01 to 90.
It is about wtX, preferably about 0.1 to 40wtχ. If the gel fraction is too small, there will be no effect, and if the gel fraction is too large, when the composition is molded, spots will occur, which will not only spoil the appearance but also cause poor physical properties.

The proportion of the irradiated propylene copolymer to the crystalline polypropylene is 0.01 part by weight or more per 100 parts by weight of the crystalline polypropylene. More preferably, it is 0.1 part by weight or more; if it is less than 0.01 part by weight, the effect of improving physical properties is small, and the crosslinked polypropylene was obtained by the same polymerization except that it did not contain alkenylsilane. Although there is no upper limit because it has better physical properties than crystalline polypropylene, it is about 50 parts by weight in terms of improved physical properties and acid formability.

In the present invention, crystalline polypropylene refers not only to a homopolymer of propylene, but also to a degree that does not lose crystallinity (usually 10 wt% or less in random, 50 wt% in block)
Examples of copolymers obtained by random or Pronk copolymerization of propylene with other olefins such as ethylene, butene-1, pentene-1, hexene-1,2-methylpentene-1, etc. Not only are many polymers already known in the literature such as patents, but a wide variety are available on the market. Further, it can be produced in the same manner as the above-mentioned method for producing a polymer of propylene and alkenylsilane, except that alkenylsilane is not used.

[ A composition can be obtained by mixing with a Kisa-1 type blender or the like, and then melt-mixing with an extruder, roll, Banbury mixer, kneader, or the like.

〔Example〕

Example 1 A vibrating machine equipped with four crushing pots each having an internal volume of 42 and containing 9 kg of steel balls each having a diameter of 12 mm was prepared. 300 g of magnesium chloride, tetraethoxysilane 60-1α1 α, and α-trichlorotoluene 45- were added to each pot under a nitrogen atmosphere and pulverized for 40 hours. 300g of the thus obtained co-pulverized material was 5f1. of titanium tetrachloride in a flask of
．． 51, after adding 1.51 toluene, 3 at 100 °C
Stir for 0 minutes, then remove the supernatant, add 1.5 L of titanium tetrachloride and 1.51 toluene, and boil at 100°.
C for 30 minutes, the supernatant liquid was removed again, and the obtained solid content was repeatedly washed with n-hexane to obtain a transition metal catalyst slurry. A sample was taken and the titanium content was analyzed and found to be 1.9 wt%.

3 os of the above transition metal catalyst in an autoclave with an internal volume of 51
g, diethyl aluminum chloride 0.124 mff1
, 0.06 m of methyl toluate, triethylaluminum O, OBd were added, 1.5 kg of propylene, 10 g of nylsilane, and 1.4 Nffi of hydrogen were added and polymerized at 75°C for 2 hours. After 2 hours, unreacted monomers were purged to form a powder. was taken out, dried, and weighed to obtain 540 g of a copolymer containing 0.08 wt% of vinylsilane. This polymer was placed in a Soxhlet extractor and extracted with n-hebutane for 6 hours, and the ratio of the extraction residue to the weight of the extracted portion (hereinafter abbreviated as +1) was 96.4%. This powder was irradiated with an electron beam (750 KV) of 2 Mrad. The xylene soluble content of this treated product (the ratio of the extracted residue when the powder was put in a 100 mt wire mesh and extracted in boiling toxylene for 6 hours) was 4wtχ, and it was measured at 240"C using a differential thermal analyzer.
The crystallization temperature measured by heating for 10 minutes at 10"C/win and measuring was 126°C. Also, the melt flow index (measured at 230°C according to ASTM D-1238, expressed in g/Login). was 14.0.

Polypropylene JHH-G95 manufactured by Mitsui Toatsu Chemical Co., Ltd.
The following physical properties were measured for a composition obtained by adding 5 parts by weight of the above-mentioned crosslinked polypropylene and granulating it using an extruder.

Flexural modulus: kg/cj ASTM 0638
(23℃) Tensile yield strength: kg/c4 AST
M D638 (23°C) Also for propylene-ethylene copolymer, Izot (notched) impact strength = kg - cs+
/cj ASTM D256-56 (20℃, -10℃
) was also measured. The results are shown in Table 1.Also, we conducted a sensory test on this all-powerful product, but there was no off-odor.
It was the same.

Comparative Example 1 Physical properties were measured in the same manner as in Example 1 without using crosslinked polypropylene, and the results shown in Table 1 were obtained.

Example 2 Polypropylene block copolymer BJHH-G manufactured by Mitsui Toatsu Chemical Co., Ltd. was used as the crystalline polypropylene, and the crosslinked polypropylene obtained in Example 1 was melt-mixed in the same manner to obtain a polypropylene resin composition. When the physical properties of this composition were similarly measured, the results shown in Table 1 were obtained.

Comparative Example 2 Physical properties were measured in the same manner as in Example 2 without using crosslinked polypropylene, and the results shown in Table 1 were obtained.

Example 3 Example 1 except that allylsilane was used instead of vinylsilane
Crosslinked polypropylene was obtained in the same manner as above, and this polymer contained 0.1 wt.chi. of allylsilane, and the xylene extraction residue was 7 wt.%. The physical properties were similarly measured and the results are shown in Table 1.

Example 4 Polymerization was carried out in the same manner as in Example 1. After 2 hours of polymerization, the temperature was lowered to 50°C, ethylene was introduced so that the ethylene partial pressure was 8 kg/cd, and triethylaluminum was further added to 0.1 kg/cd.
Add 5 m of ethylene and polymerize at 50°C for 30 minutes while maintaining the ethylene partial pressure to have an ethylene content of 8.5 w, t% and a vinyl silane content of 0.
A polymer of 0.07 wt% was obtained.

This copolymer was irradiated with 2 Mrad of T-rays in the presence of oxygen. The proportion of xylene insoluble matter was 9 wt%.

The procedure was the same as in Example 2 except that this crosslinked polypropylene was used, except that the proportion of crosslinked polypropylene used was 10 parts by weight based on 90 parts by weight of the polypropylene block copolymer. The results of measuring the physical properties are shown in Table 1.

Example 5 The same procedure as in Example 4 was carried out except that the proportion of crosslinked polypropylene used was 1 part by weight based on 99 parts by weight of the polypropylene block copolymer. The results are shown in Table 1.

Table 1 [Effects of the Invention] The composition of the present invention is easy to produce and has excellent physical properties, so it is extremely valuable industrially.

Claims (1)

[Claims] 1. A polypropylene resin composition prepared by melt-mixing 0.01 part by weight or more of a copolymer of propylene and alkenylsilane crosslinked by radiation irradiation to 100 parts by weight of crystalline polypropylene.