JP3169415B2 - Method for producing crosslinked polyolefin molded article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a crosslinked polyolefin molded article. Specifically, the present invention relates to a method for producing a crosslinked polyolefin molded article, comprising treating a polyolefin having a specific three-dimensional structure by a specific method.

[0002]

2. Description of the Related Art Syndiotactic polypropylene has been known for a long time, but recently syndiotactic polypropylene having extremely high stereoregularity can be obtained by using a catalyst comprising a special metallocene compound and an aluminoxane. Discovered (Japanese Patent Laid-Open No. 2-4130
3). On the other hand, the present inventors have already reported a method of treating a copolymer of olefin and vinylsilane with a catalyst as a method for efficiently cross-linking a polyolefin to improve physical properties (Japanese Patent Application Laid- Open No. 3-106951 ).

[0003]

The syndiotactic polyolefin having high stereoregularity is excellent in transparency and excellent in balance between rigidity and impact resistance. However, the solvent resistance, especially the solvent resistance to a high-temperature organic solvent. There is a problem that the properties are inferior to those of isotactic polyolefin. Further, even if an attempt is made to apply the above method to improve the solvent resistance by crosslinking, it is difficult to produce a copolymer with a vinylsilane having a syndiotactic structure, and there is a problem that the crosslinking reaction does not easily proceed. .

[0004]

Means for Solving the Problems The present inventors have solved the above-mentioned problems and have intensively searched for a syndiotactic polyolefin having excellent solvent resistance and completed the present invention.

That is, the present invention comprises a copolymer of allylsilane and olefin having a syndiotactic structure and a copolymer of ethylene, propylene and alkadiene. Tan attributed to copolymers of alkadiene and alkadiene
Those for which the peak of δ is not observed are the rhodium salts and
General formula (Formula 2)

Embedded image (Wherein R ¹ and R ² are the same or different and have 1 to 12 carbon atoms
Hydrogen residue, n is an integer of 0 to 3, M is titanium, zirconium
Metal selected from hafnium. )
Table 4. A method for producing a crosslinked polyolefin molded article, comprising contacting with a catalyst selected from an alkoxy compound of a Group IVB metal .

In the present invention, examples of the allylsilane include an allylsilane in which three hydrogen atoms and an allyl group are bonded to silicon, and a compound in which one to three hydrogen atoms are substituted with an alkyl residue having one to ten carbon atoms. Is exemplified.

In the present invention, examples of the olefin include α-olefins having 3 to 25 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene,
-Octene, 1-nonene, 1-decene, 1-hexadecene, 1-octadecene and other linear α-olefins, as well as 3-methyl-1-butene, 4-methyl-1-pentene, 4,4-dimethyl Branched α-olefins such as pentene can also be exemplified.

As a catalyst used for producing a copolymer of an allylsilane and an olefin having a syndiotactic structure, JAEWEN et al., J. Am. Chem. Soc., 1988, 110,
The compounds described in 6255-6256 are known. These catalysts are also effective for synthesizing a polymer having a syndiotactic structure of another α-olefin (Polymer Bullet)
In 25,567 (1991)), even if the catalyst has a different structure, it can produce a polypropylene with a syndiotactic pentad fraction of 0.7 or more obtained by homopolymerization of propylene. If available.

Specifically, there is exemplified a catalyst comprising isopropyl (cyclopentadienyl-1-fluorenyl) hafnium dichloride or isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride and aluminoxane described in the above literature. You. Here, as the aluminoxane, those having two kinds of structures represented by the following general formulas 3 and 4 (where R is a hydrocarbon residue having 1 to 3 carbon atoms and n is an integer of 1 to 50) are known. Any of these can be used, and in particular, methylaluminoxane in which R is a methyl group and n is 5 or more, preferably 10 or more is used.

[0010]

Embedded image

[0011]

Embedded image The use ratio of the aluminoxane to the transition metal compound is 10 to 100,000,000 times, usually 50 to 5000 times.

The polymerization conditions are not particularly limited, and a solvent polymerization method using an inert medium, 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 . Preferably, it is -100 to 100 ° C and normal pressure to 50 kg / cm ² . The preferred molecular weight is generally about 0.1 to 3.0 dl / g as the intrinsic viscosity measured in a 135 ° C. tetralin solution.

In the present invention, the polymerization ratio of allylsilane is preferably 0.001 to 5 mol%, more preferably 0.01 to 2 mol%, of the allylsilane in the copolymer. Is mixed with an olefin and polymerized.

Further, it is also possible to copolymerize the above-mentioned other olefins in a quantitative ratio as long as the obtained copolymer maintains a syndiotactic structure. Block copolymerization can also be performed.

The copolymer of ethylene, propylene and alkadiene used in the present invention must be well compatible with the copolymer of olefin and allylsilane having the above-mentioned syndiotactic structure. Preferably the chains are racemic. The degree of this racem is represented by a continuous racemic fraction of two or three propylene when six monomer units in the polymer chain are observed, and the structure can be known by ¹³ C-NMR. .
For example, Polymer, 1988, vo, reported by Asakura et al.
See l29 2208 for details. The molecular weight of the copolymer is 0.1 to 20 dl / g , preferably about 0.5 to 10 dl / g , as the intrinsic viscosity measured with a tetralin solution at 135 ° C.

As a catalyst suitable for producing the copolymer, a polymer having a highly syndiotactic structure and a good copolymerizability with ethylene when the above-mentioned propylene is polymerized. And the like. Specifically, the above-mentioned catalyst system is used, and the above-mentioned conditions can be used as it is for the polymerization conditions.

As the alkadiene, a non-conjugated alkadiene having 5 to 20 carbon atoms is preferably used.
Those in which the heavy bond is not at the terminal or substituted by an alkyl group are preferred, and in addition to linear ones, cyclic dienes can also be used. Specifically, 4-methyl-1,4-pentadiene, 5-methyl-1,5-hexadiene, 1,4-hexadiene, 1,6-octadiene and the like are exemplified, and the content of the alkadiene in the copolymer is from 0.001 to 0.001. It is about 10% by weight, preferably about 0.01 to 5% by weight.

In the present invention, the copolymer of allylsilane and olefin having the syndiotactic structure and the copolymer of ethylene, propylene and alkadiene have a quantitative ratio of 30.
/ 70 to 98/2, more preferably about 45/55 to 95/5. If it is less than 30/70, the rigidity is poor, and if it exceeds 98/2, the impact resistance is poor.

The above two components can be mixed using a kneader capable of excellent mixing. Further, it can be produced by a so-called block copolymerization method in which olefin and allylsilane are first polymerized and then ethylene, propylene and alkadiene or further allylsilane are copolymerized, but in order to achieve the object of the present invention, a copolymer is required. Need to be further kneaded.

As the kneader used for mixing the above two components, a kneader capable of relatively strong kneading is preferably used, and an extruder provided with a twin screw, a Banbury kneader, and the like can be used. Kneading temperature is 150 ~ 3
50 ° C., preferably 180 to 300 ° C., the degree of kneading is determined by measuring the glass transition temperature by analysis of dynamic viscoelasticity, and the degree to which the transition attributed to the copolymer of ethylene, propylene and alkadiene is no longer observed It is necessary to

Here, no transition is observed, for example,
The peak of tan δ attributed to a copolymer of ethylene, propylene and alkadiene as measured by dynamic mechanical thermal analysis is about 1/3 or less before mixing.

The mixture thus obtained is then melted by heating and molded. There is no particular limitation on the method of molding by heating and melting, and any method such as ordinary extrusion molding, injection molding, blow molding, and press molding may be used.

The catalyst used in the present invention includes:
Rhodium salts such as a triphenylphosphine complex of rhodium chloride, or an alkoxy compound of a Group IVB metal represented by the following general formula 5 , such as a titanate ester
Der Ru.

[0024]

Embedded image (In the formula, R ¹ and R ² are the same or different hydrocarbon residues having 1 to 12 carbon atoms, n is an integer of 0 to 3, and M is a metal selected from titanium, zirconium and hafnium.)

The contact with the catalyst is carried out by mixing the above catalyst with a copolymer of propylene, ethylene and alkadiene to form a catalyst-containing component, mixing with a copolymer of allylsilane when melting by heating, and molding by injection molding and press molding. Alternatively, the molding is carried out by dissolving the above-mentioned catalyst in a solvent described below and immersing the molded product previously formed by the above-mentioned molding method continuously or batchwise in the solution. When molding by heating and melting at the same time as mixing with the catalyst, the catalyst concentration in the entire composition should be 1 to 10,000p
It is about pm. As the solvent used, specifically, a hydrocarbon compound having 1 to 20 carbon atoms and a halogenated hydrocarbon compound can be used, and in particular, a halogenated hydrocarbon compound,
Aromatic hydrocarbon compounds are preferably used. Specific examples include benzene, toluene, xylene, ethylbenzene, dichloromethane, chloroform, dichloroethane, trichloroethane, perchloroethane and the like. The concentration of the catalyst when used in a solution is about 0.000001 to 1000 g / liter, usually about 0.00001 to 10 g / liter.

The preferred contact time varies depending on the concentration of the catalyst, the temperature of the catalyst solution, the shape of the copolymer, the concentration of allylsilane in the copolymer, and the like, but is usually several minutes to several tens of hours. The temperature at the time of immersion needs to be 50 ° C. or lower, and if it is higher than 50 ° C., the molded product is undesirably deformed. Usually, it is carried out at normal temperature to 50 ° C. At this time, it is of course possible to stir to assist dispersion of the catalyst.

The molding was then withdrawn from the catalyst solution and
It is heated to a temperature of not less than the melting point and below the melting point. The higher the heating temperature, the faster the reaction proceeds, but usually at about 80 to 120 ° C for 1 minute to
It takes about 10 hours.

[0028]

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

EXAMPLE 1 Isopropyl (cyclopentadienyl-1-fluorenyl) zirconium obtained by lithiation of isopropylcyclopentadienyl-1-fluorene synthesized according to a conventional method, reaction with zirconium tetrachloride and recrystallization. Using 2 mg of dichloride and 0.6 g of methylaluminoxane manufactured by Tosoh Akzo Co., Ltd. (degree of polymerization 16.1), put 10 g of allyldimethylsilane in a 2-liter autoclave, charge propylene, and polymerize at 20 ° C., polymerization pressure 3 kg / cm Polymerization was performed at 20 ° C for 2 hours while adding propylene so as to obtain ^2- G, then decalcified with methanol and methyl acetoacetate, washed with aqueous hydrochloric acid, filtered, and filtered to obtain 85 g of syndiotactic polypropylene copolymer. A coalescence was obtained. This operation was repeated to obtain about 500 g of a copolymer.

This polypropylene is about ¹³ C-NMR
The peak observed at 20.2 ppm is 0.85 of the total peak intensity attributed to the propylene methyl group, has a syndiotactic structure, and has an allyldimethylsilane content of 1.2 mol%.
Met. The intrinsic viscosity measured with a tetralin solution at 135 ° C. is 1.28 dl / g , and the ratio (MW / MN) of the weight average molecular weight to the number average molecular weight measured with 1,2,4-trichlorobenzene is 2.
Was 2.

Using the above catalyst, propylene was added in an amount of 0.5 kg / cm
² -G added further 3kg ethylene / cm ² -G, 5-methyl -
Add 10 g of 1,5-hexadiene to obtain a copolymer of ethylene, propylene and 5-methyl-1,5-hexadiene.
Manufactured at 20 ° C. The yield of this copolymer was 25 g, the ethylene content was 28% by weight, the 5-methyl-1,5-hexadiene content was 0.7% by weight, and the intrinsic viscosity was 0.79 dl / g . Further, the same operation was performed to obtain about 200 g of a copolymer. 30 parts by weight of this copolymer and 70 parts by weight of the copolymer of allyldimethylsilane were mixed with a 30 mmφ extruder (Ikegai PCM30) manufactured by Ikegai Iron Works Co., Ltd. to obtain a composition. The physical properties of this composition were as follows. Flexural rigidity is 4300 kg / cm ² , tensile yield strength is 148 kg / cm ² , elongation is 340%, Izod impact strength is 49 and 37 (23 ° C and -10 ° C respectively) kg · cm / cm
And the haze was 62%. The glass transition temperature measured by DMA was a single peak at -1.8 ° C.

The molded product was prepared by dissolving a triphenylphosphine complex of rhodium chloride at a concentration of 0.1 g / liter.
Then, it was immersed in a toluene solution at 20 ° C. for 20 hours, then taken out of the solution and heated at 100 ° C. for 3 hours. The ratio of the extraction residue extracted with boiling xylene for 12 hours after the treatment was 95.5 wt%, whereas that before the treatment was 0.5 wt%, and the physical properties were as follows. The flexural rigidity is 4800 kg / cm ² , the tensile yield strength is 159 kg / cm ² , the elongation is 260%, the Izod impact strength is 55 and 45 (23 ° C and -10 ° C respectively) kg · cm / cm, and the haze is It was 63%. This crosslinked molded article did not deform even in toluene at 80 ° C., but the molded article before contact with the catalyst was completely dissolved.

[0033]

According to the present invention, a crosslinked polyolefin molded article having a syndiotactic structure having excellent solvent resistance can be obtained, which is extremely valuable industrially.

Claims (1)

(57) [Claims] The present invention comprises a copolymer of allylsilane and olefin having a syndiotactic structure and a copolymer of ethylene, propylene and alkadiene, and after hot melt molding, the dynamic viscoelasticity of ethylene, propylene and alkadiene is analyzed. Those having no tan δ peak attributed to the copolymer were treated with rhodium salt and the following general formula (Chemical Formula 1).
1) [Formula 1] (Wherein R ¹ and R ² are the same or different and have 1 to 12 carbon atoms
Hydrogen residue, n is an integer of 0 to 3, M is titanium, zirconium
Metal selected from hafnium. )
Table IV A method for producing a crosslinked polyolefin molded article, comprising contacting with a catalyst selected from alkoxy compounds of Group IVB metals .