JPH069789A - Cross-linked polyolefin molding and its production - Google Patents

Abstract

PURPOSE:To provide a cross-linked polyolefin molding excellent in solvent resistance and also in impact resistance. CONSTITUTION:The polyolefin molding is produced by bringing an alkenylsilane- olefin copolymer into contact with a polyalkadiene and a catalyst. The molding is also produced by thermally melt molding a mixture comprising the copolymer, the polyalkadiene, and the catalyst and thermally treating the resulting molding at its distortion temp. or lower or exposing it to radiation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crosslinked polyolefin molding and a method for producing the same. Specifically, it relates to a crosslinked polyolefin molded product obtained by subjecting a specific copolymer, a polyalkadiene, and a catalyst to a contact treatment. The present invention also relates to a method for producing a crosslinked polyolefin molded product by subjecting a molded product composed of a specific copolymer, polyalkadiene, and a catalyst to heat treatment or irradiation with radiation.

[0002]

2. Description of the Related Art Crosslinking has been widely carried out for the purpose of improving mechanical properties of polyolefins, solvent resistance, heat resistance and the like. Various methods have already been proposed as cross-linking methods. A method in which a bifunctional monomer and a radical generator are mixed and heated and melted, and a monomer having a hydrolyzable group such as an alkoxysilane is used together. A method of polymerizing and molding, and then hydrolyzing with boiling water or the like to crosslink (JP-A-58-11724).
4), a method of irradiating with radiation to crosslink is well known. There is also a method proposed by the present inventors for treating a copolymer of alkenylsilane with a catalyst (Japanese Patent Application No. 1-241911).

[0003]

Although the heat resistance is considerably improved even when the crosslink density is small, the crosslink density is further improved in order to use a crosslinked molded article as a structure or to improve the solvent resistance at high temperature. Is desired.

[0004]

[Means for Solving the Problems] The present inventors have completed the present invention by intensively examining a crosslinked polyolefin molded article having excellent physical properties by solving the above problems.

That is, the present invention is a crosslinked polyolefin molded article obtained by contacting a copolymer of an alkenylsilane and an olefin, a polyalkadiene and a catalyst. In addition, a cross-linking method characterized in that after a mixture consisting of an alkenylsilane / olefin copolymer, a polyalkadiene and a catalyst is heated and melt-molded, heat treatment is carried out below the deformation temperature of the molded product, or the molded product is irradiated with radiation. It is a manufacturing method of a polyolefin molding.

In the present invention, an alkenylsilane having at least one Si--H bond is preferably used, and for example, a compound represented by the following general formula (Formula 1),

[0007]

Embedded image H ₂ C═CH— (CH ₂ ) _n —SiH _P R _3-P (wherein n is 0 to 12, p is 1 to 3 and R is a hydrocarbon residue having 1 to 12 carbon atoms). ) Can be exemplified, and specifically, vinyl silane,
Examples thereof include allylsilane, butenylsilane, pentenylsilane, and compounds in which H of some Si—H bonds of these monomers is replaced with chlorine.

As the olefin, a compound represented by the following general formula (Formula 2),

[0009]

Embedded image H ₂ C═CH—R (wherein R is hydrogen or a hydrocarbon residue having 1 to 12 carbon atoms.)
Can be exemplified, and specifically, ethylene, propylene, butene
In addition to α-olefins such as -1, pentene-1, hexene-1, 2-methylpentene, heptene-1, and octene-1, styrene and its derivatives are also exemplified.

In the present invention, the copolymer of olefin and alkenylsilane can be produced by a bulk polymerization method or a gas phase polymerization method in addition to the solvent method using an inert solvent. As the catalyst used for production, a catalyst composed of a transition metal compound and an organometallic compound is generally used, and a 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 organoaluminum compound, and if necessary, an oxygen-containing organic compound. Such as a catalyst system composed of an electron donating compound, a carrier such as magnesium halide, or a transition metal compound catalyst obtained by supporting titanium halide on the carrier treated with an electron donating compound and an organoaluminum compound, if necessary. A catalyst system consisting of an electron-donating compound such as an oxygen-containing organic compound or a reaction product of magnesium chloride and an alcohol is dissolved in a hydrocarbon solvent and then treated with a precipitating agent such as titanium tetrachloride to form a hydrocarbon solvent. Insolubilize, treat with electron donating compounds such as ester and ether if necessary, then Examples include catalyst systems comprising a transition metal compound catalyst and an organoaluminum compound obtained by a method of treatment with titanium rogenide, and optionally an electron-donating compound such as an oxygen-containing organic compound (see, for example, various references below. An example is given of: Ziegler-Natta Ca
talysts and Polymerization by John Boor Jr (Academi
c Press), Journal of Macromorecular Science Reviews
in Macromolecular Chemistry and Physics, C24 (3) 355
-385 (1984), C25 (1) 578-597 (1985)).

Alternatively, the polymerization can be carried out by using a transition metal catalyst soluble in a hydrocarbon solvent and a catalyst composed of 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 methyl group, ethyl group, propyl group, butyl group and hexyl group. Examples of the halide include chlorine, bromine and iodine. Further, an aluminoxane which is an oligomer or a polymer obtained by reacting the above organoaluminum with water or crystal water can also be used.

The alkenylsilane and the olefin are polymerized in a proportion of 0.1 to 30 mol%, preferably 0.
It is 5 to 10 mol%. When it is used as a mixture with another olefin polymer, it is 1 to 20 mol%.

The molecular weight of the polymer is not particularly limited, but from the viewpoint of improving the physical properties of the molded product, the higher the molecular weight, the higher the degree of crosslinking can be achieved with a small alkenylsilane content. Also, in terms of moldability, if the molecular weight is too high, the moldability will deteriorate. Therefore, the intrinsic viscosity measured with a tetralin solution at 135 ° C is preferably 0.5 to
It is about 10, particularly preferably about 1.0 to 5.0.

A graft copolymer obtained by graft-polymerizing an alkenylsilane on a polyolefin (for example, the following mixed polyolefin can be used) can be used for the purpose of the present invention. There is no particular limitation as to the method for grafting alkenylsilane on the polymer, and the method and conditions used for ordinary graft copolymerization can be used. Normally, the polyolefin and alkenylsilane used are radical initiator Graft copolymerization can be easily carried out by heating above the decomposition temperature of.

In the present invention, the following polyolefins may be mixed and used, if desired. The polyolefin used as a mixture with the above copolymer, if necessary, is an olefin represented by the above general formula (formula 2), specifically ethylene, propylene, butene-1, pentene-1, hexene.
-1,2-methylpentene, heptene-1, octene-1, and other α-olefins, homopolymers of styrene or its derivatives, random copolymers of each other, or olefins alone, or small amounts of other Examples thereof include so-called block copolymers produced by copolymerizing with an olefin and then copolymerizing two or more kinds of olefins.

Methods for producing these polyolefins are already known and various brands are available on the market. It can also be produced by the same method as the method for producing a copolymer of olefin and alkenylsilane except that alkenylsilane is not used.

In the present invention, examples of the polyalkadiene include polybutadiene, polyisoprene, polychloroprene, and the like.
Those to which H group, carboxylic acid group, etc. are added, or copolymers of butadiene, isoprene, chloroprene, etc. with other olefins, such as styrene-butadiene rubber, acrylonitrile-butadiene rubber, or ethylene-propylene-alkadiene copolymer Although examples thereof include coalesce, particularly polybutadiene, polyisoprene, polychloroprene, polybutadiene having an OH group, a carboxylic acid group, etc. added to the terminal, styrene-butadiene rubber, acrylonitrile-butadiene rubber and the like have a high content of alkadiene. Those are preferably used.

The ratio of the polyalkadiene to the alkenylsilane / olefin copolymer is usually 0.1 to 60 parts by weight, preferably 1.0 to 40 parts by weight, per 100 parts by weight of the alkenylsilane / olefin copolymer. is there. If it is less than this, the improvement effect is small, and if it is more than this, the rigidity becomes poor, which is not preferable.

The above-mentioned alkenylsilane / olefin copolymer, polyalkadiene and, if necessary, the polyolefin to be mixed are not particularly limited, and they may be mixed in a powder state by a conventional method and used as they are.
Further, it is melt-kneaded and granulated. Molding is carried out prior to contact with the catalyst described below, or it is contacted with the catalyst simultaneously with molding. Examples of the molding method include injection molding, extrusion molding and press molding. The alkenylsilane concentration in the mixture is 0.01 to 20 mol%, preferably 0.1 to 20 mol%.
When mixed so as to be 10 mol%, a crosslinked polyolefin having a high concentration of crosslinking points can be obtained.

In the present invention, as the catalyst, a rhodium salt such as a triphenylphosphine complex of rhodium chloride, or an alkoxy compound of a metal of Group IVB of the periodic table represented by the following general formula (Formula 3) such as a titanate ester is used. It is preferably exemplified.

[0024]

Embedded image R ¹ _n M (OR ² ) _4-n (wherein 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 titanium). , A metal selected from zirconium and hafnium.).

In the present invention, the molded product is then contact-treated with a catalyst. The contact treatment method is also not particularly limited, but it is common to contact the molded product with a catalyst solution. After contact with the catalyst solution, the crosslinking reaction can be promoted by taking it out of the solution and heating it. The contact treatment temperature is generally from room temperature to the melting point of the polymer, and it is preferable to contact the catalyst solution at room temperature to 100 ° C. In the absence of solvent, it is common to heat to 50 to 160 ° C. Further, as a method of contacting with the catalyst at the same time as molding, a catalyst is allowed to coexist during mixing, or a mixture containing a copolymer of alkenylsilane and a mixture containing a catalyst without containing a copolymer of alkenylsilane. Can be prepared in advance, and then the two can be mixed, heated, melted and molded.

As the solvent used here, specifically, a hydrocarbon compound having 1 to 20 carbon atoms and a halogenated hydrocarbon compound can be used, and particularly, a halogenated hydrocarbon compound,
Aromatic hydrocarbon compounds are preferably used. Specifically, benzene, toluene, xylene, ethylbenzene,
Dichloromethane, chloroform, dichloroethane, trichloroethane, perchloroethane etc. are exemplified and usually
It is used by dissolving it so that the catalyst concentration becomes 0.1 to 10,000 ppm.

The proportion of the catalyst used in the case of heating and melting and contacting with the catalyst is such that the catalyst concentration in the entire mixture is 1 to
It is preferably 10000 ppm, especially 10 to 5000 ppm. When the alkenylsilane concentration in the mixture is 0.01 to 20 mol%, preferably 0.1 to 10 mol%, a crosslinked polyolefin molded product having a high concentration of crosslinking points can be obtained.

The above-mentioned alkenylsilane / olefin copolymer, polyalkadiene, catalyst and, if necessary, the hot-melt mixing method of the polyolefin to be mixed are not particularly limited, and they are mixed in a powder state by a usual method and molded as they are. Alternatively, the pellet containing the catalyst and the pellet containing the copolymer of alkenylsilane (if the copolymer of the alkenylsilane and the catalyst are contained in the same pellet, crosslinking proceeds during granulation, resulting in poor moldability. ) Can be produced and then both can be mixed and molded. Although the reason is unknown, the presence of the polyalkadiene suppresses the progress of cross-linking when the copolymer of the catalyst and the alkenylsilane is melted by heating, and facilitates heat-melt molding. Examples of the molding method include injection molding, extrusion molding, and press molding, but it is particularly effective when applied to extrusion molding and injection molding. The molding temperature is not particularly limited as long as it is a temperature at which the polymer flows and is equal to or lower than the decomposition temperature, and molding can be performed at a normal molding temperature. Specifically, 150-300 ℃
It is common to do in.

In the present invention, the heat-melted molded product can be further heat-treated to further promote crosslinking. As for the heating temperature, a higher temperature is preferable as long as the molded product is not deformed, because a molded product having a high crosslinking density can be obtained by a heat treatment in a short time. The heating temperature is usually 80 to 17
The temperature is 0 ° C. and the heating time is several minutes to several hundred hours. When a copolymer of propylene and alkenylsilane is used, heating at 155 ° C for 1 hour is sufficient.

In the present invention, it is also possible to further crosslink by irradiating the heat-melted molded product with radiation. Here, examples of the radiation include electron beams, γ rays, X rays, and ultraviolet rays. Irradiation is performed after forming a desired molded article from the mixture of the above-mentioned alkenylsilane copolymer, polyalkadiene and catalyst. As the radiation source, γ rays and X rays are preferable from the viewpoint of transparency, and the irradiation dose is
It is usually about 0.1 to 100 Mrad, preferably about 1 to 50 Mrad. The irradiation temperature is not particularly limited, and it is possible to carry out at a relatively high temperature because the crosslinking is partially progressed by the above-mentioned heat-melt molding, and at a high temperature, quenching of radicals after irradiation becomes unnecessary. It is usually carried out at room temperature to 170 ° C.

[0031]

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

Example 1 A vibration mill equipped with four grinding pots having an inner volume of 4 liters and containing 9 kg of steel balls having a diameter of 12 mm was prepared. In each pot under a nitrogen atmosphere, 300 g of magnesium chloride, 60 ml of tetraethoxysilane and 45 of α, α, α-trichlorotoluene
ml was added and crushed for 40 hours. Co-ground product 300 thus obtained
In a 5 liter flask, add 1.5 liters of titanium tetrachloride and 1.5 liters of toluene, and add 30 liters at 100 ° C.
After stirring for a minute, the supernatant was removed. Add again 1.5 liters of titanium tetrachloride and 1.5 liters of toluene,
The mixture was stirred at 100 ° C for 30 minutes, and the supernatant was removed. Then, 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%.

40 ml of toluene, 100 mg of the above transition metal catalyst, 0.128 ml of diethylaluminum chloride, 0.06 ml of methyl p-toluate and 0.20 ml of triethylaluminum were placed in an autoclave having an internal volume of 5 liters under a nitrogen atmosphere, and 1.5 kg of propylene and 80 g of vinylsilane were added. In addition, hydrogen
After 0.5 N liter was injected under pressure, polymerization was carried out at 75 ° C. for 2 hours. After the polymerization, unreacted propylene was purged, the powder was taken out, filtered and dried to obtain 480 g of powder.

The powder obtained had an intrinsic viscosity (hereinafter abbreviated as η) of 2.35 measured with a tetralin solution at 135 ° C.
The melting point and crystallization temperature were measured as the maximum peak temperature by raising or lowering the temperature at 10 ° C / min using a differential thermal analyzer. Melting point 156 ° C, crystallization temperature 120 ° C
Was a crystalline propylene copolymer. According to elemental analysis, it contained 1.3 wt% of vinylsilane unit.

300 g of the obtained copolymer was added with polybutadiene (
100 g of Nipol BR1220 (trade name, manufactured by Nippon Zeon Co., Ltd.) was added, mixed with an extruder of 20 mmφ and then press-molded to obtain a molded product having a thickness of 1 mm. This molded product was dipped in a toluene solution in which n-butyl titanate was dissolved to a concentration of 10 g / liter to impregnate it, and treated at 80 ° C. for 2 hours. Then, the molded product was taken out of the solution and treated at 120 ° C. for 3 hours. This molded product was not deformed at 200 ° C. at all, the extraction residue ratio extracted with boiling xylene for 12 hours was 95%, and the weight increase of the molded product after extraction was only 15%.

The following physical properties of the molded product were measured. Flexural rigidity: kg / cm ² ASTM
D747 (23 ℃) Tensile yield strength: kg / cm ² ASTM
D638 (23 ℃) Izod (with notch) Impact strength: kg ・ cm / cm ASTM
D256 (20 ℃, -10 ℃) Flexural rigidity 16500kg / cm ² , Tensile yield strength 320kg / c
m ² , Izod impact strength is 55, 35 kgcm / cm respectively
Met.

Comparative Example 1 A molded product obtained by molding and crosslinking in the same manner as in Example 1 without using polybutadiene was evaluated in the same manner.
Although it did not deform even at 00 ° C, the ratio of the extraction residue extracted with boiling xylene for 12 hours was 94%, and the weight increase of the molded product after extraction was 95%. In addition, the flexural rigidity of the molded product is 20.
400 kg / cm ^2, the tensile yield strength is 405kg / cm ^2, an Izod impact strength was respectively 8, 2kg · cm / cm.

Example 2 A propylene copolymer having an allylsilane content of 0.25 wt% was prepared by polymerizing in the same manner as in Example 1 except that 1 g of allylsilane was used instead of vinylsilane. The η of the copolymer was 1.85, the melting point was 158 ° C., the crystallization temperature was 115 ° C., and the extraction residue ratio after extraction with boiling n-heptane for 6 hours was 96.8%.
Using 500g of this powder, replace the polybutadiene with styrene butadiene rubber (Nipol 15
07) A molded product was produced in the same manner as in Example 1 except that 100 g was used, and was treated in the same manner as in Example 1. The physical properties of the molded product were as follows. Bending rigidity is 16000 kg / cm ² , tensile yield strength is 310 kg / cm ² , and Izod impact strength is respectively.
It was 65 and 41 kg.cm/cm. The molded product was not deformed at 200 ° C. at all, and the extraction residue ratio after extraction with boiling xylene for 12 hours was 92%, and the weight increase of the molded product after extraction was only 35%.

Example 3 To 300 g of the copolymer obtained in Example 1, 100 g of polybutadiene (manufactured by Nippon Zeon Co., Ltd., Nipol BR1220 trade name) was added, and 20 mm
Pellets containing 10000ppm of triphenylphosphine complex of rhodium chloride prepared separately by mixing with φ extruder (commercial isotactic polypropylene, manufactured by Mitsui Toatsu Chemicals, Inc., Mitsui Noblene JHH-G and rhodium chloride) Manufactured by melting and mixing the triphenylphosphine complex of 1.) at 100: 1 and manufactured by Komatsu Ltd. (FKS5
A molded product was manufactured by the injection molding machine of 5-1). This molded product
It heat-processed at 155 degreeC for 2 hours. The physical properties of this molded product were as follows. Flexural rigidity 17,000 kg / cm ² , tensile yield strength 320 kg / cm ² , Izod impact strength 54,
It was 39 kg · cm / cm.

This molded product did not deform at 200 ° C. at all, and the extraction residue ratio after extraction with boiling xylene for 12 hours was 99.
%, And the increase in the weight of the molded product after extraction was only 18%. The injection molded product was extracted with boiling xylene for 12 hours, and the ratio of the extraction residue was 35%, and there was no problem in molding.

Comparative Example 2 A molded product obtained by molding and crosslinking in the same manner as in Example 1 without using polybutadiene was evaluated in the same manner.
Although it did not deform even at 00 ° C, the ratio of the extraction residue extracted with boiling xylene for 12 hours was 94%, and the weight increase of the molded product after extraction was 95%. In addition, the flexural rigidity of the molded product is 20.
The tensile yield strength was 500 kg / cm ² , the tensile yield strength was 415 kg / cm ² , and the Izod impact strength was 8, 2 kg · cm / cm ² , respectively.

Example 4 Using 500 g of the copolymer obtained in Example 2, styrene-butadiene rubber (manufactured by Nippon Zeon Co., Ltd.) was used instead of polybutadiene.
A molded product was prepared in the same manner as in Example 3 except that 100 g of Nipol 1507) was used, and was treated in the same manner as in Example 3. The physical properties of the molded product were as follows. Flexural rigidity is 16300 kg / cm
² , the tensile yield strength was 330 kg / cm ² , and the Izod impact strengths were 62 and 45 kg · cm / cm ² , respectively.

The molded product did not deform at 200 ° C. at all,
The ratio of the extraction residue extracted with boiling xylene for 12 hours was 99%, and the weight increase of the molded product after extraction was only 16%.
Incidentally, the ratio of the extraction residue extracted with boiling xylene for 12 hours before irradiation with γ-rays was 41%, and there was no problem in molding.

Example 5 The molded product obtained in Example 3 was further irradiated with γ-rays at 5 Mrad / h and 1 Mrad.
After irradiation, the physical properties were measured and the bending rigidity was 17100 kg /
cm ² , tensile yield strength was 340 kg / cm ² , and Izod impact strength was 52 and 38 kg · cm / cm, respectively.

This molded product did not deform even at 200 ° C.,
The ratio of the extraction residue extracted with boiling xylene for 12 hours was 99%, and the weight increase of the molded product after extraction was only 12%.
The injection molded product was extracted with boiling xylene for 12 hours, and the ratio of the extraction residue was 35%, and there was no problem in molding.

Comparative Example 3 A molded product obtained by molding and crosslinking in the same manner as in Example 5 without using polybutadiene was evaluated in the same manner.
Although it did not deform even at 00 ° C, the ratio of the extraction residue extracted with boiling xylene for 12 hours was 93%, and the weight increase of the molded product after extraction was 85%. In addition, the flexural rigidity of the molded product is 20.
000 kg / cm ² , tensile yield strength was 410 kg / cm ² , and Izod impact strength was 7 and 2 kg · cm / cm, respectively.

Example 6 As in Example 5, except that 500 g of the copolymer powder obtained in Example 2 was used, and 100 g of styrene-butadiene rubber (Nipol 1507, manufactured by Nippon Zeon Co., Ltd.) was used instead of polybutadiene. When a molded product was prepared as described above and treated in the same manner as in Example 5, the physical properties of the molded product were as follows. The flexural modulus was 16200 kg / cm ² , the tensile yield strength was 320 kg / cm ² , and the Izod impact strengths were 62 and 44 kg · cm / cm, respectively.

The molded product did not deform at 200 ° C. at all,
The ratio of the extraction residue extracted with boiling xylene for 12 hours was 98%, and the weight increase of the molded product after extraction was only 15%.
Incidentally, the ratio of the extraction residue extracted with boiling xylene for 12 hours before irradiation with γ-rays was 41%, and there was no problem in molding.

[0049]

Industrial Applicability The molded product of the present invention is a crosslinked polyolefin molded product having excellent solvent resistance and impact resistance and is industrially extremely valuable.

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Claims (4)

[Claims] 1. A crosslinked polyolefin molded article obtained by subjecting a copolymer of an alkenylsilane and an olefin, a polyalkadiene, and a catalyst to a contact treatment. 2. A crosslinked polyolefin molded article obtained by contact-treating a molded article composed of an alkenylsilane / olefin copolymer and a polyalkadiene with a catalyst. 3. A crosslinked polyolefin molded article, which comprises subjecting a mixture of an alkenylsilane / olefin copolymer, a polyalkadiene and a catalyst to heat-melt molding and then heat-treating at a temperature not higher than the deformation temperature of the molded article. Method. 4. A process for producing a crosslinked polyolefin molded product, which comprises subjecting a molded product to irradiation with radiation after a mixture comprising an alkenylsilane / olefin copolymer, a polyalkadiene and a catalyst is heated and melt-molded.