JPS6295303A - Novel ethylene copolymer - Google Patents

Abstract

PURPOSE:To provide a novel copolymer composed of ethylene unit, styrene comonomer unit and ethylenic unsaturated monomer unit at specific ratios and having effectively improved properties required for the modification of electrically conductive material, foamed material and polymer, etc. CONSTITUTION:A copolymer having a density of 0.860-0.970g/cm<3> and a melt index of 0.05-100g/10min can be produced by high-pressure radical polymerization of 85.0-99.995(mol)% ethylene unit, 0.005-5%, preferably 0.01-2% styrene comonomer unit of formula (R1 is 3-5C alkenyl; R2 is H, Cl or 1-2C alkyl) (e.g. allylstyrene, isopropenylstyrene, 4-styryl-1-butene, etc.) and 0-10% ethylenic unsaturated monomer unit (e.g. propylene, butene-1, etc.) usually under 500-4,000kg/cm<2> pressure at 50-400 deg.C.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a novel ethylene copolymer.

More specifically, the present invention provides an ethylene copolymer useful for modifying polymers such as electrical insulation materials, foam materials, and engineering plastics.

(Prior art) Olefin polymers, especially ethylene polymers, propylene polymers, etc., have excellent mechanical properties, processability, electrical properties, and other properties, and are economically inexpensive, so they are used as electrical insulating materials and foamed materials. It is used in a variety of fields as raw materials and processed products such as films, pipes, and containers.

Furthermore, olefin copolymers in which functional groups are introduced into the olefin polymer are also well known in order to improve the performance of the olefin polymer.

For example, polyethylene itself has low dielectric loss and high dielectric strength, and when cross-linked, its heat resistance is greatly improved and is used as an excellent insulating material. It is desired to improve the performance as an insulator.

As an attempt to improve the above-mentioned dielectric strength, a method of introducing an aromatic ring into an ethylene polymer has been proposed.

l) A method of blending aromatic polymers such as polystyrene with polyethylene or olefin polymers (Japanese Patent Publication No. 38-20
No. 717, JP-A-50-142651, JP-A-52-
54187) 2) A method of blending a block copolymer of styrene and conjugated dienes with polyethylene (Japanese Unexamined Patent Publication No. 52-41884) 3) A method of graft polymerizing styrene with polyethylene (Japanese Patent Publication No. 54-18760) Publication) 4) Method of impregnating polyethylene with electrical insulating oil (Japanese Patent Application Laid-Open No. 49-33938
(No. Publication), etc., have been disclosed.

However, none of the above methods has been able to reach a sufficient amount of K to improve dielectric strength.
In method 1), the compatibility between polyethylene or polyolefin and styrene polymer is poor. Method 2) results in a decrease in heat resistance and deterioration in extrusion processability. Method 3) improves the breaking strength of polyethylene against impact voltage in the high temperature range, instead of requiring complicated equipment and processes such as graft polymerization of styrene onto pre-crosslinked polyethylene. It has the disadvantage that its breaking strength under impact voltage is inferior to that of untreated raw polyethylene.

Although method 4) is an adequate method, the insulating oil may bleed when used for a long time or due to changes in the environment, and its effectiveness is inferior to the above three methods. First, there is a desire for materials that are stable over a long period of time and have higher dielectric strength.

Furthermore, one of the important properties of electrical insulating materials, particularly resins for electrical cables, is that they have excellent crosslinking properties. However, with conventional polyethylene resins, when trying to increase the molding speed to improve productivity, the gel fraction decreases because the crosslinking speed is not sufficient, and therefore the molding speed is naturally limited, and it is difficult to increase the molding speed. is difficult.

In addition, in conventional polyethylene resins for power cables, the gel fraction does not improve unless the amount of crosslinking agent is added, and the heat deformation rate at high temperatures above the melting point increases significantly. There is a strong need for sexual improvement.

In the field of foam materials, polyethylene foam has the advantage of being highly elastic and has a large strain recovery capacity even against repeated stress, but mold foam molding can produce simple shapes such as plate-like objects. In bead foam molding (a method of foam molding using pre-expanded particles and steam heating), which can only form foams with complex shapes, the gas diffusion during foaming is rapid, so the molding conditions are It was difficult to set up, and it was not possible to mold it widely.

It is also possible to blend particles pre-foamed by impregnating polystyrene and polyethylene with a foaming agent, which are good for bead foam molding, and foam molding, but such molding methods tend to cause the fusion of different types of beads. Unfortunately, it is impossible to produce a practical foam molded product.

In recent years, a method for producing expandable polyethylene beads has been proposed which can improve the above-mentioned drawbacks, prevent the escape of the blowing agent, and obtain a foam with a high magnification.

For example, 1) polyethylene particles, styrene monomer, and polymerization catalyst are dispersed in an aqueous medium, a gaseous or liquid physical blowing agent is normally pressurized into this, and styrene is suspended and polymerized under heat and pressure to improve foaming properties. 2) Disperse polyethylene particles, styrene monomer, and polymerization catalyst in an aqueous medium and heat. A method of impregnating styrene-modified polyethylene particles obtained after turbidity polymerization under pressure with a physical blowing agent (Japanese Patent Publication No. 52-10150, Japanese Unexamined Patent Publication No. 1983-1983)
-85187, Japanese Patent Publication No. 49-97884) 3) A method of producing a porous material by immersing a foaming agent into a polyolefin resin in which styrene is graft-polymerized by irradiation with ionizing radiation (Japanese Patent Publication No. 44-19382) Although a number of methods have been proposed, such as No. 1 (Japanese Patent Publication No. 1), all of them require complicated processes and equipment.

Furthermore, in the production of crosslinked foams, it is absolutely necessary to shorten the molding time in order to increase productivity.

Conventionally, known methods for shortening molding time include lowering the decomposition temperature of the crosslinking agent and blowing agent and increasing the decomposition rate. For the latter, it has been proposed that the molding temperature be increased.

However, when a crosslinking agent and a blowing agent having a low decomposition temperature are used, decomposition is likely to occur during the kneading operation for producing an ethylene copolymer composition for crosslinking and foaming, making stable extrusion over a long period of time difficult. Furthermore, there is the problem that the expansion ratio of the foam after molding fluctuates. iTh, a crosslinking agent with a low decomposition temperature, is chemically unstable and is inconvenient to handle.

Furthermore, if the molding temperature is raised to speed up the decomposition rate of the crosslinking agent and blowing agent, scorching may occur in the molded product.
Since the temperature difference between the skin and the interior becomes significant, the distribution of the degree of crosslinking causes disadvantages such as fluctuations in physical properties and narrow molding range, and there is a desire to develop resins with excellent crosslinking properties.

In addition, styrene craft is used as a modifier for making mixed compositions of resins such as polyphenylene ether and polycarbonate, that is, resins called engineering plastics, and olefin resins, or as a modifier for the impact resistance and processability of engineering plastics. Polyolefins or styrene polymers are often used (JP-A-58-7448, JP-A-58-98359).
However, since enes, engineering plastics, and olefin polymers inherently have problems such as poor compatibility, further improvements are desired.

(Problems to be Solved by the Invention) In view of the above-mentioned points, the present invention has been made as a result of intensive studies and has found that the performance required for the above-mentioned electrical insulating materials, foamed materials, and modification of polymers, etc., does not cause the conventional problems. The object of the present invention is to provide a new ethylene copolymer that can improve the performance of the ethylene copolymer more effectively.

(Means for Solving the Problem) The present invention provides 850 to 99.995 moles of ethylene units, 0.005 to 5 moles of comonomer units represented by the following formula (I), and ethylenically unsaturated monomers. The present invention provides a novel ethylene copolymer containing 0 to 10 molar units, having a density of 0860 to 0.970 g/cd, and a melt index of 0.05 to 100 g/lo min.

The comonomer represented by the above formula (I) includes allylstyrene, methylallylstyrene, ethylallylstyrene, chloroallylstyrene, ingropenylstyrene, methylisopropenylstyrene, chloroisopropenylstyrene, 4-styryl-1 -Butene, 4-methylstyryl-
1-butene, 4-ethylstyryl-1-butene, 4-chlorostyryl-1-butene, 3-styryl-1-butene, 2-styryl-1-butene, 5-styryl-1-heptene, 5-methylstyryl -1-heptene, 5-chlorostyryl-1-heptene, etc.

These comonomers are synthesized, for example, as follows.

Allyl styrene is obtained by reacting styrene bromide with magnesium metal to create a so-called ``GIJ'' compound, which is then reacted with allyl bromide. It is obtained by dehydrogenating ethylisopropylbenzene obtained by reacting inopropenylstyrene and propylene. 4-Styryl-1-butene is obtained by reacting vinylbenzyl chloride with metallic magnesium to produce a Grignard compound, and reacting this with allyl bromide.

The content of the comonomer in the copolymer is 0.005 to 5 mol per unit, preferably 0.01
~2 molar ratio is appropriate.

When the above-mentioned comonomer dispersion is less than 0,005 mol, there is almost no modification effect of the ethylene copolymer, and 5 mol φ
If it exceeds 100%, it becomes economically expensive, and especially in high-pressure radical polymerization, the amount of fiber/cal consumed increases, and the advantage of industrial production is lost.

Further, the ethylenically unsaturated monomers of the present invention include propylene, butene-],]hexene-14-methylpentene-1
, octene-1, decene], olefins having 3 to 10 carbon atoms, styrene, vinyl esters of C2 to C3 alkanecarboxylic acids, methyl acrylic acid or methacrylate, acrylic acid or ethyl methacrylate, Acrylic acid or methacrylic acid esters such as propyl acrylate or methacrylate, glycidyl acrylate or glycidyl methacrylate; ethylenically unsaturated substances such as acrylic acid, methacrylic acid, maleic acid, fumaric acid 2 and maleic anhydride; It is at least one selected from the group of carboxylic acids or their anhydrides, ethylenically unsaturated carboxylic acid amides such as acrylamide, methacrylic acid amide, maleic acid amide, and fumaric acid amide.

The content of the ethylenically unsaturated carmer is used in the range of 0 to 10 mol, preferably 0 to 7 mol, more preferably θ to 5 mol.

The ethylene copolymer of the present invention can be produced using known methods such as ionic polymerization using a Ziegler type catalyst or radical polymerization under high pressure. Preferably legal.

For example, in ionic polymerization using a Ziegler type catalyst, a solid catalyst component containing a small amount of tomomagnesium and titanium, such as magnesium metal, magnesium hydroxide, magnesium carbonate, magnesium oxide, etc., and a metal selected from silicon, aluminum, and calcium and a magnesium atom are used. double salts, double oxides, carbonates, chlorides, hydroxides, etc., as well as these inorganic solid compounds, are treated or reacted with oxygen-containing compounds, sulfur-containing compounds, aromatic hydrocarbons, and halogen-containing substances. In the presence of a catalyst in which a titanium compound is supported on an inorganic solid compound containing magnesium by a known method and an organoaluminum compound is combined, polymerization is carried out in the same manner as the polymerization reaction of olefins using a normal Ziegler type catalyst. It can be obtained by doing.

That is, all reactions are carried out in the absence of oxygen, water, etc., in a gas phase or in the presence of an inert solvent, with the monomer itself still being used as a solvent. The polymerization conditions for the above olefin are a temperature of 20 to 300°C, preferably 40 to 200°C, and a pressure of normal pressure to 70ky/, ffl-9. Preferably 2 to 60 kg/d - chill in the evening. Although the molecular weight can be adjusted to some extent by changing polymerization conditions such as polymerization temperature and catalyst molar ratio, it is effectively carried out by adding hydrogen to the polymerization system. Great hydrogen concentration,
A two-stage or more multi-stage polymerization reaction with different polymerization conditions such as polymerization temperature can also be carried out without any hindrance.

- 10,000, Radical polymerization method under high pressure means polymerization pressure of 5
00-4000kg/ffl, preferably 100
0-3500 to 9/cd, reaction temperature 50-40
The monomers are reacted simultaneously or stepwise in a seed or back reactor under conditions of preferably 100-350°C, in the presence of a free radical catalyst and a chain transfer agent, and if necessary auxiliaries. A method of contacting and polymerizing.

The free radical catalysts include the customary initiators such as peroxides, hydroperoxides, azo compounds, amine oxide compounds, oxygen, and the like.

As a chain transfer agent, hydrogen, propylene, butene-1
, C5-C20 or higher saturated aliphatic hydrocarbons and... rogane-substituted hydrocarbons, such as methane, ethane, propane, butane, inobutane, n-hexane, n-
Hebutane, cycloparaffins, chloroform and carbon tetrachloride, C7 to C20 or higher saturated aliphatic alcohols such as methanol, ethanol, propatool and isopropanol, C7 to C20 or higher saturated aliphatic carbonyl compounds, For example, carbon dioxide,
Included are acetone and methyl ethyl ketone as well as aromatic compounds, side-lighting compounds such as toluene, diethylbenzene and xylene.

(Function and effects of the invention) The ethylene copolymer of the present invention produced as described above,
In particular, ethylene copolymers prepared by high-pressure radical polymerization are less susceptible to tree phenomenon due to contamination of foreign matter such as catalyst residues than those produced by ionic polymerization as electrical insulating materials, and can significantly improve dielectric strength. In addition, crosslinking properties can be significantly improved.

Furthermore, the ethylene copolymer of the present invention is an excellent material as a modifier for foaming materials and polymers. Other olefin polymers (including copolymers)
, Polyac IJ O nitrile, polyamide, polycarbonate, ABS resin, polystyrene, polyphenylene oxide, polyvinyl alcohol resin, vinyl chloride resin, vinylidene chloride resin, thermoplastic resin such as polyester steel fat, petroleum resin, coumaroinodene resin and phenol. Heat curing of resin, melamine resin, etc.! 4tt fat, ethylene-propylene copolymer rubber (EPR).

EPDM, etc.), 5BRSNBR, butadiene rubber, IkoR, chloroprene rubber, isoprene rubber, styrene-butadiene-styrene-bronok copolymer, and other synthetic rubbers or natural rubbers.

In addition, in the present invention, organic/inorganic fillers, antioxidants, lubricants, various organic/inorganic pigments, ultraviolet inhibitors,
Additives such as antistatic agents, dispersants, copper damage inhibitors, neutralizing agents, foaming agents, plasticizers, antifoaming agents, flame retardants, crosslinking agents, flowability improvers, weld strength improvers, and nucleating agents are added. I don't mind if you do that.

(Example) Examples are shown below.

Example 1 A metal autoclave type reactor with an internal volume of 3.8 tons and equipped with a stirrer was sufficiently purged with nitrogen and ethylene, and then 1650 g of ethylene and 340 g of n-hexane as a chain transfer agent were added.
g, allyl styrene/・1 g, and further charged 58 m9 of jitter/yari-butyl peroxide, which is a polymerization initiator, temperature: 170°C, pressure: 1600 kg/c++I
, polymerization was carried out for 1 hour.

The resulting polymer was dissolved in heated carbon tetrachloride, poured into a large amount of acetone, reprecipitated, and distributed separately. After repeating this procedure several times, it was purified by washing with acetone and vacuum drying. The amount of polymer produced was 195J. Also JI
Measured according to SK 6760, the melt index is 1.1/10 minutes, and the density is 0.931. ! ? /l
-i.

The obtained polymer was molded into a 7-plate having a thickness of about 500 μm by heating and compression, and the ethylene copolymer of the present invention was confirmed by infrared spectroscopic analysis. Figure 1 shows its infrared absorption spectrum. This spectrum includes absorptions seen in ordinary polyethylene, as well as K 913cm-' and 1640cm-
Absorption due to allyl group is seen at ', and 1 512 cm
-', 806 cm-' absorption due to the aromatic ring can be seen. Furthermore, the absorption caused by vinyl occlusion at 903 cm-' and 1632 cm-', which was observed in the infrared spectrum of the allylstyrene monomer, almost completely disappeared. From these results, allylstyrene is copolymerized with ethylene to produce a polymer with the following structure.

Analysis by 13C-NMR revealed that the content of allylstyrene units copolymerized in the obtained polymer was 0.31 molar. In addition, as a result of examining the intramolecular distribution of allylstyrene units by the same analysis, it was found that when ethylene units are represented by E and allylstyrene units are represented by A, 1/V-E-A-Es
-ψ-, E-A-A-E-8~, -Hair E-A to A-
They combine in the form A-Eφ^, and the proportion of each is 9.
3%, 7%, and 0%, and they are copolymerized almost randomly.

The average molecular weight of the obtained polymer was determined by the intrinsic viscosity method in decalin and was found to be 37,000.

Example 2 Polymerization and purification analysis of the resulting polymer were carried out in the same manner as in Example 1, except that 1 g of allylstyrene and 20 g of diternary butylperoquinde were charged.

The amount of polymer produced was 257 g, the tart index of the obtained polymer was 3.1 g/10 min, and the density was 0.9319.
/d, the content of allylstyrene units copolymerized in the polymer was 0.006 molar. The average molecular weight determined by the intrinsic viscosity method was 37,000.

Example 3 After a metal autoclave type reactor with an internal volume of 0.321 and a stirrer was sufficiently purged with nitrogen and ethylene, 120I ethylene, 359 allylstyrene, and benzene as a chain transfer agent were charged with IOF, and further polymerization was started. 20~ of tertiary butyl peroxyacetate as an agent was charged, and polymerization was carried out at a temperature of 135 DEG C., a pressure of 1.000 kg/d, and a time of 1 hour.

Purification 1 analysis of the produced polymer was carried out in the same manner as in Example 1.The amount of produced polymer was 13&, the melt index of the obtained polymer was 10.2&/10 minutes, the density was 0.9399/d, and the average molecular weight was I got it for 35,000. The content of allylstyrene units copolymerized in the obtained polymer was 41 moles. Moreover, the intramolecular distribution of allylstyrene units is -E -A -EVV-1-NSA-E -A -A
-E~ to -M-E-A-A-A-A-E□, and the proportions of τ are 71%, 29%, and 0%, respectively, and they are copolymerized almost randomly.

Example 4 4-styryl-1-butene was used instead of allylstyrene.
! ? Polymerization and purification and analysis of the resulting polymer were carried out in the same manner as in Example 1, except that 15 μm of 37091 di-tert-butyl peroxide and n-hexane were charged.

The amount of polymer produced was 1639, the melt index of the obtained polymer was 1.6 g/10 min, and the density was 0.930.
It was 9/d.

FIG. 2 shows the infrared absorption spectrum of the obtained polymer. In this spectrum, in addition to the absorptions seen in ordinary polyethylene, absorptions due to butenyl groups are seen at 913 cm-' and 1640α-1, and absorption due to aromatic rings is seen at 1607 cm-'. Also, the letter 903m-' seen in the infrared absorption spectrum of 4-styryl-1-butene monomer
absorption and the shoulder of 1632α-1 have completely disappeared. From these results, 4-styryl-1-butene is copolymerized with ethylene to produce a polymer with the following structure.C-C,-C=C13C-NMR analysis reveals that 4-styryl-1-butene is copolymerized with ethylene. The content of 4-styryl-1-butene units copolymerized with is 03
It was in charge of 2 moles. Also, according to the same analysis, 1-styryl-
As a result of examining the intramolecular distribution of 1-butene units, the table shows E for ethylene units and P for 4-phenyl-1-butene.+-/V-E-P-EW%/, -E-P-P-E ^ha^
, E-P-P-P-E- are bonded in proportions of 94, 6, and 0, respectively, and are almost randomly copolymerized.

The average molecular weight of the obtained polymer according to the intrinsic viscosity method was 37.
,000.

Example 5 4-styryl-1-butene was used instead of allylstyrene.
Polymerization and purification and analysis of the resulting polymer were carried out in the same manner as in Example 1, except that 9 mg of ditertiary-butyl peroxide was charged.

The amount of polymer produced was 261 g, the tart index of the obtained polymer was 2.89 / 10 minutes, and the density was 0.93.
197d, 4-styryl-1- copolymerized in the polymer
The content of butene units was 0.06 molar. The average molecular weight determined by the intrinsic viscosity method was 37,000.

Example 6 4-styryl-1-butene was used instead of allylstyrene.
．． 5,? Polymerization and purification and analysis of the resulting polymer were carried out in the same manner as in Example 3, except that 10 liters of tert-butyl peroxyacetate were charged.

The amount of polymer produced was 20 g, the melt index of the obtained polymer was 8.1/10 minutes, and the density was 0.9379/d.
, the average molecular weight was 36.000. The content of 4-styryl-1-butene units copolymerized in the obtained polymer was 37 molar, and the intramolecular distribution of 4-styryl-1-butene units was E-P-E, E- P-P-EAAJ-1-E
-P-P-P-E bonding ratios are 74, 26, and 0, respectively, and the copolymerization is almost random.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the results of the infrared absorption spectrum of Example 1, and FIG. 2 is a diagram showing the results of the infrared absorption spectrum of Example 4. Teshin ■ne Ichimasa W4 1986 211 left day

Claims (3)

[Claims] (1) Ethylene units 85.0 to 99.995 mol% and the following formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (
I) Comonomer unit represented by [wherein R_1 represents a linear or branched alkenyl group having 3 to 5 carbon atoms, R_2 represents a hydrogen atom, a chlorine atom, or an alkyl group having 1 to 2 carbon atoms] 0. 005 to 5 mol%, and a density of 0.860 to 0.860, containing 0 to 10 mol% of ethylenically unsaturated monomer units.
0.970g/cm^3, melt index 0.0
A novel ethylene copolymer with a yield of 5 to 100 g/10 min. (2) A patent characterized in that the monomer represented by the formula (I) is at least one comonomer selected from the group of allylstyrene, isopropenylstyrene, and 4-styryl-1-butene. A novel ethylene copolymer according to claim 1. (3) The pressure of the ethylene copolymer is 500 to 4000 k.
3. The novel ethylene copolymer according to claim 1 or 2, which is a copolymer obtained by high-pressure radical polymerization at a temperature of 50 to 400°C.