JP3184574B2 - Method for producing polypropylene resin molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a molded article of polypropylene. More specifically, the present invention relates to a method for producing a crosslinked polypropylene molded article containing an inorganic filler using a specific copolymer.

[0002]

2. Description of the Related Art It is well known that an inorganic filler is mixed with polypropylene for the purpose of improving the rigidity and heat resistance of the polypropylene. It is also known to use a vinylsilane-propylene copolymer to improve the adhesion between the inorganic filler and the polypropylene and further improve the physical properties, and further to irradiate the obtained molded product with radiation to crosslink ( JP-A-3-72540).

[0003]

The above-mentioned method of crosslinking with a radiation using a vinylsilane copolymer is excellent in that it gives a molded article having good physical properties, but has a problem that the operation is complicated. .

[0004]

Means for Solving the Problems The present inventors diligently studied a molding method which solved the above-mentioned problems, and found that a specific method was extremely excellent, and completed the present invention.

Namely, the present invention provides (1) of propylene and the following
General formula (Formula 2)

Embedded image (Where n is 0 to 12, p is 1 to 3, and R is 1 to 12 carbon atoms.
Hydrocarbon residues. ) And pellets of a copolymer of an alkenyl silane represented by (2) polypropylene and Si-H groups
A method for producing a crosslinked polypropylene molded article, comprising: mixing a mixture of catalyst pellets capable of reacting to give Si radicals , wherein either one of the pellets contains an inorganic filler, followed by melt molding. It is.

[0006] alkenylsilane used in the present invention is a compound represented by the above following general formula (Formula 2).

Specifically, vinyl silane, allyl silane,
Butenyl silane and pentenyl silane can be exemplified.

In the present invention, a copolymer obtained by changing a part of propylene of a copolymer of propylene and alkenylsilane to another olefin and using a copolymer may be used. Penten-1,
Hexene-1, 2-methylpentene, heptene-1, octene
-1 and the like, and those copolymerized so as to be less than 10% by weight of the whole polymer can be used.

In the present invention, the copolymer of propylene and alkenylsilane can be produced by a bulk polymerization method or a gas phase polymerization method in addition to a solvent method using an inert solvent. Further, as a catalyst used for the production, it is common to use a catalyst comprising a transition metal compound and an organometallic compound, and titanium halide is preferably used as the transition metal compound, and an organoaluminum compound is preferably used as the organometallic compound. .

Specifically, titanium tetrachloride obtained by reducing titanium tetrachloride with metallic aluminum, hydrogen or organic aluminum is modified with an electron donating compound, an organic aluminum compound, and if necessary, an oxygen-containing organic compound. A catalyst system comprising an electron donating compound such as a compound, or a carrier such as magnesium halide or a transition metal compound catalyst obtained by supporting them with an electron donating compound and supporting a titanium halide, and an organoaluminum compound. A catalyst system comprising an electron-donating compound such as an oxygen-containing organic compound, or a reaction product of magnesium chloride and an alcohol in a hydrocarbon solvent, and then treating with a precipitant such as titanium tetrachloride to form a hydrocarbon solvent Insoluble in
A transition metal compound catalyst and an organoaluminum compound obtained by a treatment with an electron-donating compound such as an ester or an ether, if necessary, followed by a treatment with a titanium halide, and an electron-donating compound such as an oxygen-containing organic compound as necessary. Examples include catalyst systems composed of compounds (for example, various examples are described in the following literature. Ziegler-Natta).
Catalysts and Polymerization by John Boor Jr (Acade
mic Press), Journal of Macromorecular Science Revie
ws in Macromolecular Chemistry and Physics, C24 (3)
355-385 (1984) and C25 (1) 578-597 (1985)).

Alternatively, the polymerization can be carried out using a catalyst comprising a transition metal catalyst soluble in a hydrocarbon solvent and an aluminoxane.

As the electron-donating compound, oxygen-containing compounds such as ethers, esters, orthoesters and alkoxysilicon compounds can be preferably exemplified, and alcohols, aldehydes, water and the like can also be used.

As the organoaluminum compound, trialkylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, and alkylaluminum dihalide can be used. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. Illustrative examples of the halide include chlorine, bromine and iodine. Aluminoxane, which is an oligomer to a polymer obtained by reacting the above-mentioned organoaluminum with water or water of crystallization, can also be used.

Here, the polymerization ratio of alkenylsilane and propylene is not particularly limited, but is usually about 0.001 to 30 mol%, preferably 0.1 to 10 mol%.
It is.

The molecular weight of the polymer is not particularly limited, but is preferably about the same as or less than the molecular weight of the polypropylene used as a mixture. As a preferable molecular weight, the intrinsic viscosity measured with a tetralin solution at 135 ° C. is 0.
It is about 1 to 10 dl / g .

In the present invention, it is also possible to mix (1) the pellets of the copolymer of propylene and alkenylsilane with the polypropylene described below, wherein 0 to 95% by weight of the propylene-alkenylsilane copolymer is converted to polypropylene. Can be changed. At this time, it is preferable that the alkenylsilane content in the pellets is about 0.01 to 2.

In the present invention, any polypropylene may be used as long as it is a crystalline polypropylene, and not only homopolymers of propylene but also copolymers of propylene with α-olefins such as ethylene, butene and hexene. It may be a polymer or a so-called propylene block copolymer in which propylene is first polymerized substantially and then ethylene and propylene are polymerized. The molecular weight of the polypropylene is 0.1 to 10 d in terms of intrinsic viscosity measured with a tetrahydronaphthalene solution at 135 ° C.
It is generally about 1 / g .

In the present invention, the catalyst may be Si—H
Any substance that reacts with a group to give a Si radical may be used, and examples thereof include compounds of transition metals such as rhodium and titanium, amines, peroxides, diazo compounds, and the like. Particularly, triphenylphosphine complex of rhodium chloride, titanium Acid esters are preferably used.

The ratio of the catalyst to polypropylene is generally such that the catalyst concentration in the pellets is about 1 to 10,000 ppm, and the catalyst concentration after mixing the two types of pellets is 0.1 to 1000 ppm. It is common to make it.

In the present invention, the inorganic filler is not particularly limited, and various known fillers used for improving the physical properties of polypropylene can be used, such as talc, kaolin, mica, calcium carbonate, calcium silicate, calcium sulfate, calcium sulfite, glass Etc. are available. There is no particular limitation on the particle size of these fillers, or the shape of fibers, scales, whiskers, etc., and various sizes and shapes can be used depending on the purpose. Prior to use, the surface of the filler may be treated with a coupler. The proportion of the inorganic filler in the total composition may be determined according to the purpose, but is usually 5 to 100 parts by weight of the total mixture.
90 parts by weight.

The inorganic filler can be mixed with either one or both of the pellets produced prior to molding. Particularly, when the inorganic filler is mixed with a pellet containing a copolymer of propylene and alkenylsilane, the inorganic filler can be mixed with the copolymer. Good and preferred filler contact.

There are no particular restrictions on the method of mixing the above components or mixing with known additives such as antioxidants, ultraviolet absorbers, lubricants, antistatic agents, and other nucleating agents that are added as necessary. The components of the respective pellets are mixed with a Henschel mixer, a V-type blender or the like, and then melt-mixed with an extruder, a roll, a Banbury mixer, a kneader or the like, and granulated once to form pellets.

The two types of pellets thus obtained are then mixed and molded by a method such as extrusion molding, injection molding, press molding, etc., to obtain a crosslinked molded product. The molding temperature is not particularly limited and can be at a normal molding temperature.
0-300 ° C.

[0024]

The present invention will be further described with reference to examples.

Example 1 A vibrating mill equipped with four 4-liter crushing pots containing 9 kg of steel balls having a diameter of 12 mm and having a capacity of 4 liters is prepared. 300 g of magnesium chloride, 112 ml of diisobutyl phthalate and 60 ml of titanium tetrachloride were put in each pot under a nitrogen atmosphere, and pulverized for 40 hours. 300 g of the co-ground product thus obtained was placed in a 5-liter flask, and 3 liters of toluene were added.
For 30 minutes, and then the supernatant was removed. Again, 3 liters of toluene was added, and the mixture was stirred at 80 ° 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. A part of the sample was analyzed for titanium content.
%Met.

In a 5-liter autoclave, under a nitrogen atmosphere, 40 ml of toluene, 100 mg of the above transition metal catalyst, 0.1 ml of dimethylcyclohexyldimethoxysilane and 0.20 ml of triethylaluminum were placed, and 1.5 kg of propylene was added.
After adding 40 g of vinyl silane and pressing in 1N liter of hydrogen,
Polymerization was performed at 75 ° C. for 2 hours. After the polymerization, unreacted propylene was purged, and the powder was taken out and filtered and dried to obtain 890 g of powder. The same reaction was repeated to obtain about 2.5 kg of a polymer.

The intrinsic viscosity of this polymer measured with a tetralin solution at 135 ° C. is 1.68 dl / g , and the melting point and crystallization temperature are raised or lowered at 10 ° C./min using a differential thermal analyzer. When measured as the maximum peak temperature, the melting point was 159 ° C and the crystallization temperature was 119 ° C. According to elemental analysis, it contained 1.1 wt% of a vinylsilane unit.

The above copolymer 5 was added to 100 parts by weight of a block copolymer of propylene and ethylene having an ethylene content of 7.5 wt%.
Parts by weight, white mica (Kuraray Mica 3
00w) was previously treated with 3-aminopropyltriethoxysilane in water-ethanol and thoroughly dried, and 30 parts by weight were added and mixed, and then mixed and granulated by an extruder. On the other hand, 1 part by weight of a triphenylphosphine complex of rhodium chloride was added to 100 parts by weight of the block copolymer and mixed to obtain a pellet in the same manner. Next, 95 parts by weight of the filler-containing pellets and 5 parts by weight of the catalyst-containing pellets were mixed and molded by an injection molding machine of FKS 55-1, manufactured by Komatsu Ltd. for measuring physical properties of 2 mm and 1 mm in thickness. Was obtained.

When the physical properties of this molded product were measured, the flexural modulus (kg / cm ² : ASTM D790 (23 ° C.)) was 19,500.
kg / cm ² , tensile yield strength (kg / cm ² : ASTM D638 (23
° C.)) is 375 kg / cm ^2, Izod (notched) impact strength (kg · cm / cm: ASTM D256 (23 ℃, -10 ℃)) , respectively 9.5, was 5.3 kg · cm / cm.

Comparative Example 1 The same procedure as in Example 1 was carried out except that molding was performed without using a pellet containing a catalyst, and the flexural modulus was 17,500 kg / c.
m ² , tensile yield strength was 345 kg / cm ² , and Izod (notched) impact strength was 4.5 and 2.8 kg · cm / cm, respectively.

Example 2 Copolymer of propylene and vinylsilane obtained in Example 1 10
A molded product was obtained in the same manner as in Example 1 except that 0 part by weight and 30 parts by weight of talc were mixed to form a pellet and used as one component, and the physical properties were measured. The flexural modulus was 23500 kg / c.
m ² , tensile yield strength was 425 kg / cm ² , and Izod (notched) impact strength was 8.6 and 3.9 kg · cm / cm, respectively.

Comparative Example 2 The same procedure as in Example 2 was carried out except that molding was performed without using a pellet containing a catalyst, and the flexural modulus was 18,500 kg / c.
m ² , tensile yield strength was 401 kg / cm ² , and Izod (notched) impact strength was 6.1 and 2.0 kg · cm / cm, respectively.

[0033]

By carrying out the method of the present invention, a cross-linked molded article having good physical properties can be easily obtained, which is extremely valuable industrially.

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Claims (1)

(57) [Claims] 1. A (1) of propylene and the following general formula (Formula 1) ## STR1 ## (Where n is 0 to 12, p is 1 to 3, and R is 1 to 12 carbon atoms.
Hydrocarbon residues. ) And pellets of a copolymer of an alkenyl silane represented by (2) polypropylene and Si-H groups
A method for producing a crosslinked polypropylene molded article, comprising: mixing a mixture of catalyst pellets capable of reacting to give Si radicals , wherein either one of the pellets contains an inorganic filler, followed by melt molding. .