JPH03106951A - Production of crosslinked polyolefin - Google Patents

Abstract

PURPOSE:To carry out the crosslinking simply and easily in a short time and prevent the deformation of a molded article by crosslinking a copolymer of an alkenylsilane and an olefin in the presence of a hydrosilylation catalyst. CONSTITUTION:0.001-30mol% alkenylsilane and an olefin are copolymerized in the presence of a Ziegler-Natta catalyst comprising a transition metal catalyst and an organometallic compd. The resulting copolymer is crosslinked with 0.00001wt.% or higher (based on the olefin in the copolymer) hydrosilylation catalyst such as a triphenylphosphine complex of rhodium, a group VIII metal catalyst, e.g. chloroplatinic acid (salt), a radical initiator, e.g. an azo compd., and an amine, e.g. triethylamine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing crosslinked polyolefins. Specifically, the present invention relates to a method for producing a crosslinked polyolefin in which a main chain containing a polymer of alkenylsilane and olefin is treated with a specific compound.

[Conventional technology]

Crosslinking reactions are carried out for the purpose of improving the physical properties of polyolefins. However, in α-olefins such as polypropylene, depolymerization of the main chain takes priority over crosslinking reactions, so simply generating radicals by decomposing peroxide or irradiating with radiation does not cause crosslinking reactions. , rather the decomposition progresses and the molecular weight decreases. For this reason, it is common practice to graft a monomer, such as alkoxyvinylsilane, which can undergo a crosslinking reaction upon hydrolysis, onto a polyolefin, and then crosslink it (for example, JP-A-117244-1983). [Problems to be Solved by the Invention] Polymers obtained by grafting alkoxyvinylsilane onto polyolefins have a certain effect on improving physical properties through crosslinking of polyolefins, but the process of assembling the grafted polymers is complicated, and the essence of the reaction is difficult. Due to these problems, it is unavoidable that physical properties deteriorate due to cleavage of the main chain, and it is also difficult to introduce various comonomers into the main chain. To deal with this, it is known to introduce vinylsilane into the main chain and then crosslink with water (for example, U.S. Pat. No. 3,223,686), but the crosslinking reaction with water is relatively slow to proceed and takes a long time. There were problems such as exposure to heat and deformation of the precept-shaped objects due to exposure to high temperatures.

[Means to solve the problem]

The present inventors have earnestly searched for a method for producing crosslinked polyolefins that solves the above problems, and have completed the present invention. That is, the present invention is a method for producing a crosslinked polyolefin, which comprises treating a copolymer of alkenylsilane and olefin with a hydrosilylation catalyst. The present invention is also a method for producing a crosslinked polyolefin, characterized in that a mixture of an alkenylsilane-olefin copolymer and a polyolefin is treated with a hydrosilylation catalyst.

In the present invention, the copolymer of alkenylsilane and olefin can be obtained by polymerizing olefin and alkenylsilane using a so-called Ziegler-Natta catalyst consisting of a transition metal catalyst and an organometallic compound.
An example is disclosed in No. 223-686. Furthermore, a graft copolymer obtained by graft polymerization of polyolefin by heat treatment with alkenylsilane in the presence of a radical polymerization initiator such as peroxide may also be used. As the alkenylsilane, those having at least one Si-H bond are preferably used,
For example, general 2〇zC=CH-(CHz)*-SiH
Examples include compounds represented by J3-r (in the formula, n is 0 to 12, p is 1 to 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 1 to 3 Si-H bonds of these heptanomers is replaced with chloro. Examples of olefins include compounds represented by the general formula 1hC=CH-R (wherein R is a hydrocarbon residue having 1 to 12 carbon atoms), specifically ethylene, propylene, butene-1, pentene-1 ,
In addition to α-olefins such as hexene-1, 2-methylpentene, heptene-1, and octene-1, styrene or derivatives thereof are also exemplified.

In the present invention, for the copolymer of olefin and alkenylsilane, the catalyst consisting of TiCI and triethyl aluminum described in the above-mentioned US patent can also be used, but it is more preferable to use various highly active polyolefins that have been developed since then. The catalyst provided is utilized. 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 composed of a transition metal compound and an organometallic compound, a titanium halide is preferably used as the transition metal compound, and an organoaluminum compound is preferably used as the organometallic compound. For example, titanium trichloride obtained by reducing titanium tetrachloride with metallic aluminum, hydrogen, or organic aluminum 5nium is modified with an electron-donating compound, and an organic aluminum ξnium compound,
Furthermore, if necessary, a catalyst system consisting of an electron-donating compound such as an oxygen-containing organic compound, or a transition metal compound obtained by supporting titanium halide on a carrier such as magnesium halide, or a carrier treated with an electron-donating compound. A catalyst system consisting of a catalyst and an organoaluminum compound, and if necessary an electron-donating compound such as an oxygen-containing organic 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 used. By treatment, it becomes insolubilized in hydrocarbon solvents, and if necessary, esters,
Catalyst system consisting of a transition metal compound catalyst obtained by treatment with an electron-donating compound such as ether, followed by treatment with titanium halide, an organoaluminum compound, and if necessary an electron-donating compound such as an oxygen-containing organic compound. (For example, various examples are described in the following documents, Ziegler-Natta Ca
Talysts and Polyserization
n by John Boor Jr.
c Press), Journal of Macro
molecular science reviews
in Macromolecular Chemist
ry and Physics, C24(3) 355
-385 (1984), C25 (1) 578-59
7 (1985)). Alternatively, polymerization can also be carried out using a catalyst consisting of a transition metal catalyst soluble in a hydrocarbon solvent and aluminoxane.

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 the organic argonium compound, trialkyl aluminum, dialkyl aluminum halide, alkylaluminum sesquihalide, alkylaluminium dihalide can be used, and the alkyl group includes methyl group, ethyl group, proyl group, butyl group, hexyl group, etc. are exemplified, and chlorine, bromine, and iodine are exemplified as halides.

In addition, as aluminoxane, oligomers obtained by reacting the above-mentioned organoaluminum with water or water of crystallization are used.
It is a bolimar.

There is no particular restriction on the polymerization ratio of arvinylsilane and olefin;
It is approximately mol χ, preferably 0.1 to 10 mol χ.

There is no particular restriction on the molecular weight of the polymer, but if it is intended to improve the physical properties by mixing, it is preferable that the molecular weight is the same as or lower than that of the polyolefin. In some cases, it may be used by performing the same polymerization as polyolefin (composition, molecular weight, etc.) except that it contains alkenylsilane. For example, block copolymerization may be performed to copolymerize alkenylsilane only in the first stage or only in the second stage. May be polymerized.

There are no particular restrictions on the method of grafting alkenylsilane to polyolefin, and the methods and conditions used for ordinary graft copolymerization can be used. Usually, the method and conditions used for graft copolymerization are heated to a temperature higher than the decomposition temperature of the radical initiator in the presence of the polyolefin and alkenylsilane used. This allows easy graft copolymerization.

The polyolefins used in the present invention include olefins represented by the general formula 1{2C=CH-R (wherein R is a hydrocarbon residue having 1 to 12 carbon atoms), specifically ethylene, propylene, butene-1, In addition to α-olefins such as bentene-1, hexene-1, 2-methylpentene, hebutene-1, and octene-1, not only homopolymers of styrene or its derivatives but also random copolymers of each other,
Alternatively, a so-called block copolymer, which is produced by first copolymerizing a certain olefin alone or with a small amount of other olefins, and then copolymerizing two or more types of olefins, is exemplified. It is particularly effective to apply the method of the present invention to α-olefins such as propylene or copolymers thereof, which are difficult to crosslink when used alone. Methods for producing these polyolefins are already known, and various brands are available on the market. Further, it can be produced in the same manner as the above-mentioned method for producing a polymer of olefin and 7-rukenylsilane except that alkenylsilane is not used.

In the present invention, the copolymer of alkenylsilane and olefin is usually mixed with a polyolefin that does not contain alkenylsilane, or only the copolymer of alkenylsilane is used without mixing polyolefin that does not contain alkenylsilane. can. The ratio of the alkenylsilane and olefin copolymer used in a mixture depends on the alkenylsilane content in the copolymer, but the ratio of the copolymer in the mixture is usually 0.1stX or more. Preferably, 0.005w of alkenylsilane is present in the polyolefin when treated with a hydrosilylation catalyst.
T! It is preferable to make it exist to some extent.

During mixing, it is possible to use various known additives and there are no particular limitations.

In the present invention, the hydrosilylation catalyst is not particularly limited, and any known hydrosilylation catalyst can be used, such as a triphenylphosphine complex of rhodium, a metal catalyst of Group I of the periodic table such as chloroplatinic acid or its salt (organosilicon compound), etc. 's Chemistry, Makoto Kumada et al., published by Kagaku Doujin, page 165),
Examples include radical initiators such as azo compounds and akines such as triethylamine. Since the hydrosilylation reaction is relatively fast, the reaction proceeds sufficiently at a temperature around room temperature, but it is possible to complete the reaction in a single hour by heating the polyolefin to a temperature higher than the glass transition temperature of the polyolefin. In addition, noble metal catalysts have extremely high activity and can proceed with crosslinking with a small amount of catalyst, and if dispersion is sufficient, 0.0% relative to polyolefin.
The reaction proceeds sufficiently even at about 00001wtX. The crosslinking reaction is usually carried out after the copolymer is shaped, but if the degree of crosslinking is relatively low, the shaping can also be carried out after the crosslinking reaction. Contact is generally carried out by dissolving the hydrosilylation catalyst in a solvent that is relatively compatible with the polyolefin, and crosslinking is carried out by immersing the compound in the solution of the hydrosilylation catalyst and heating if necessary. . Further, in the case of a product having a low alkenylsilane content, it is possible to crosslink it by heating and melting it after mixing with a catalyst, and by doing so, it is also possible to produce a crosslinked polyolefin or a shaped polyolefin containing a crosslinked polyolefin all at once.

The crosslinking reaction can be carried out in an inert gas atmosphere or in the presence of oxygen, and the environment can be selected depending on the purpose.

〔Example〕

The present invention will be further explained by showing examples below. 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 m is prepared. 300 g of magnesium chloride, 60 W1 of tetraethoxysilane, and 45-α,α,α-trichlorotoluene were placed in each pot under a nitrogen atmosphere, and the mixture was pulverized for 40 hours. 300 g of the co-pulverized material obtained in this way was put into a 51 flask, and titanium tetrachloride 1
．． 52 and toluene 1.52 and ioo'c 3
The mixture was stirred for 0 minutes, and then the supernatant liquid was removed. Add 1.5l of titanium tetrachloride and 1.5j2 of toluene again,
The mixture was stirred at 0'C for 30 minutes, and then the supernatant was removed.
Thereafter, the solid content was washed repeatedly 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 200 d, under a nitrogen atmosphere, 40 ml of toluene, 50 ml of the above transition metal catalyst, 0.128 d of diethylargonium chloride, 0.06 d of methyl p-toluate, and 0.0 ml of triethyl algonium chloride.
Add 201, then vinyl silane 4. After compressing Og, charge propylene to 5 kg/cj, and
Polymerization was carried out at a constant pressure for 2 hours at °C. Thereafter, the slurry was taken out, filtered and dried to obtain 43 g of powder. The intrinsic viscosity (hereinafter abbreviated as η) was measured with a tetralin solution at 135°C, and the melting point and crystallization temperature were measured as the maximum peak temperature by increasing or decreasing the temperature at 10"C/sin using a differential thermal analyzer. However, the obtained powder had a η of 1.6 l, a melting point of 156°C, and a crystallization temperature of 118°C.
It was a crystalline polypropylene. According to elemental analysis, it contained 11% by weight of vinylsilane units.

Add 0.1 phenolic antioxidant to the obtained copolymer.
wt! The sheet was then press-molded to make a sheet with a thickness of IIIal, which was then placed in a solution of triphenylphosphine complex of IImg rhodium chloride dissolved in 10ld of toluene and treated at 60°C for 20 hours. After that, the sheet was taken out and extracted with boiling xylene for 12 hours, and the insoluble content was 95-t2. When the formed sheet was directly extracted with boiling xylene for 12 hours, the insoluble content was 0.2wtχ. Comparative Example 1 Polymerized in the same manner as in Example 1 without copolymerizing vinylsilane, with η of 1.60, melting point of 158°C, crystallization temperature of 110°C, extraction when extracted with ln-heptane at boiling point of 110°C for 6 hours. Obtaining polypropylene with a residual ratio of 96.8X,
The same procedure as in Example 1 was carried out. When extracted with boiling xylene for 12 hours, the insoluble content was 0.6 wtχ.

Example 2 The same procedure as in Example 1 was carried out by mixing the copolymer of brobylene and vinylsilane obtained in Example 1 and the polypropylene obtained in Comparative Example 1 at a ratio of 1:10. When extracted with boiling xylene for 12 hours, the insoluble content was 4htχ.

Example 3 The procedure of Example 1 was repeated except that chloroplatinic acid (TV) was used instead of the rhodium catalyst. The insoluble matter extracted with boiling xylene for 12 hours was 96 x.

Example 4 Polymerization was performed using 0.4 g of allylsilane instead of vinylsilane to produce 1 to. A polypropylene copolymer of 13wtX was produced. The copolymer has a η of 1.58, a melting point of 158°C, a crystallization temperature of 118°C, and a ratio of extraction residue when extracted with boiling n-heptane for 6 hours is 96.2.
It was χ. To 100 g of this powder was added a triphenylphosphine complex of sulfur chloride at 1 mH, and after mixing well, it was shaped into a sheet at 230°C. When extracted with boiling xylene for 12 hours, the insoluble content was 21wtχ.

Comparative Example 2 The same procedure as in Example 4 was repeated except that no rhodium catalyst was used, and the insoluble matter was extracted with boiling xylene for 12 hours, and the insoluble content was 0.6 wtX.

〔Effect of the invention〕

Claims (1)

[Claims] 1. A method for producing a crosslinked polyolefin, which comprises treating a copolymer of alkenylsilane and olefin with a hydrosilylation catalyst. 2. A method for producing a crosslinked polyolefin, which comprises treating a mixture of an alkenylsilane and olefin copolymer and a polyolefin with a hydrosilylation catalyst.